text:
Targeting Erosion Control: Adoption of Erosion Control Practices. A Report from a National Research Project.
ERIC Educational Resources Information Center
West, Peter; And Others
Research analyzed adoption of erosion control practices by farm operators in two counties in each of four states: Alabama, Missouri, Tennessee, and Washington. Analysis was based on farm survey data and technical and financial assistance information from county Soil Conservation Service (SCS) and Agricultural Stabilization and Conservation Serviceģ
Erosion Control Progress in the HUA IDAHO SNAKE-PAYETTE RIVERS --HUA WATER QUALITY PROJECT FINAL REPORT
O'Laughlin, Jay
Erosion Control Progress in the HUA IDAHO SNAKE-PAYETTE RIVERS -- HUA WATER QUALITY PROJECT FINAL water quality within the HUA used in #12;2 -- Erosion Control IDAHO SNAKE-PAYETTE RIVERS -- HUA WATER QUALITY PROJECT FINAL REPORT this 8-year project was improved erosion control methods. Erosion control
NSDL National Science Digital Library
This lesson will discuss erosion control practices in the agricultural and construction environments. The impact of erosion management practices will be demonstrated with exercises using a USLE calculator.
Erosion by water: vegetative control
Technology Transfer Automated Retrieval System (TEKTRAN)
Vegetation controls erosion by dissipating the erosive forces of rainfall and runoff (erosivity - the strength of the forces causing erosion) and by reducing the susceptibility of soil to erosion (erodibility - how easily soil can be detached and transported). Vegetation alters the partitioning of r...
Controlled ultrasonic tissue erosion
NASA Astrophysics Data System (ADS)
Cain, Charles
Controlled ultrasonic tissue erosion has many clinical applications, including the placement of very precise sharply defined perforations in biological interfaces and membranes with focused ultrasound. With carefully chosen acoustic parameters, tissue can be rapidly eroded away at a constant etching rate. The maximum erosion rate for minimal propagated energy is obtained by using very short high intensity pulses. The etching rate is higher with shorter pulse durations. For short pulses less than 10 cycles of the drive frequency, an optimum pulse repetition rate exists which maximizes the etching rate. Higher gas saturation in the surrounding medium reduces the etching rate and reduces the spatial sharpness of the holes produced. Most of the erosion appears to be produced in the first several cycles of the therapy pulse. For example, a series of short (about 3 cycles) focused pulses of 2100 W/cm2 (Isppa) at 788 kHz can erode a very well defined 2 mm diameter hole in a 1 mm thick sample of fresh pork atrial posterior wall in about 1 min at the optimum pulse repetition rate (about 18 kHz). Controlled ultrasonic tissue erosion may provide an effective image guided noninvasive tool in treatment of neonatal patients with hypoplastic left heart syndrome. Without the mixing of oxygenated blood across perforations placed in the atrial septum, these infants do not survive.
Weathering and Erosion Video Project
NSDL National Science Digital Library
Amber Thibedeau
Using a digital video recorder, 6th grade students will create an informational video that teaches 4th grade (or 5th as an FCAT review) students about weathering and erosion using images from around the school and local areas. This will most likely be a long-term project, depending on how many digital video recorders and computers are available.
Lincoln Park shoreline erosion control project: Monitoring for surface substrate, infaunal bivalves and eelgrass, 1993
L. D. Antrim; R. M. Thom; W. W. Gardiner
In 1988, the US Army Corps of Engineers and the City of Seattle placed material on the upper beach at Lincoln Park, in West Seattle, Washington. The fill served to mitigate shoreline erosion that had caused undercutting and collapse of the seawall in several places. A series of pre- and post-construction studies have been conducted to assess the impacts to
Projected changes in US rainfall erosivity
NASA Astrophysics Data System (ADS)
Biasutti, M.; Seager, R.
Downscaled rainfall projections from 21 climate models from the CMIP5 (Coupled Model Intercomparison Project Phase 5) archive are used to estimate future changes in rainfall erosivity in the continental Unites States. To estimate erosivity from rainfall in the absence of sub-hourly data, we have used both daily rainfall values and the modified Fournier index - which is based on monthly rainfall accumulation - and derived the scaling relationship between rainfall and erosivity from observational estimates of both. The expectation of overall increase in erosivity is confirmed by these calculations, but a quantitative assessment is marred by large uncertainties. Specifically, the uncertainty in the method of estimation of erosivity is more consequential than that deriving from the spread in climate simulations and leads to changes of uncertain sign in parts of the southwest and Texas. We suggest that progress can be made by establishing a more reliable functional relationship between daily rainfall and erosivity.
Lincoln Park shoreline erosion control project: Monitoring for surface substrate, infaunal bivalves and eelgrass, 1993
Antrim, L.D.; Thom, R.M.; Gardiner, W.W. [Battelle/Marine Sciences Lab., Sequim, WA (United States)
In 1988, the US Army Corps of Engineers and the City of Seattle placed material on the upper beach at Lincoln Park, in West Seattle, Washington. The fill served to mitigate shoreline erosion that had caused undercutting and collapse of the seawall in several places. A series of pre- and post-construction studies have been conducted to assess the impacts to marine biota of fill placement and movement of surface substrate. This study was designed to monitor infaunal bivalves and eelgrass from intertidal areas in and adjacent to the area of original fill placement. Findings from this survey were compared to previous survey results to determine (1) if recruitment of infaunal bivalves to the fill area has occurred, (2) if infaunal bivalve densities outside the fill area are stable, and (3) if eelgrass distribution and abundance have remained stable along the adjacent shoreline. To maximize comparability of findings from this survey with previous studies, sampling techniques, transects, and tidal elevations were consistent with previous studies at this site.
The International Erosion Control Society - Photo Gallery
NSDL National Science Digital Library
Users can access photographs of various forms of erosion, erosion damage, and "before and after" photos showing how the problem was brought under control. Each photograph is accompanied by a description of the activity which is taking place.
Using Compost for Erosion Control and RevegetationĀ
Mukhtar, Saqib
slope erosion by reducing water-flow velocity and the volume of sediment coming off the slope. *Associate Professor and Extension Agricultural Engineering Specialist ? Waste Management PREPARED IN COOPERATION WITH THE TEXAS COMMISSION... agricultural lands. Research reports from academia, the EPA, state departments of transportation (DOTs) and other sources suggest that compost can be effective in controlling erosion from construction sites, including road rights-of-way, general construction...
Modifying Erosion Control Structures for Ecological Benefits
Technology Transfer Automated Retrieval System (TEKTRAN)
Edge-of-field water control structures known as drop pipes are widely employed to control gully erosion, particularly along incised streams. Previous research showed that incidental habitats created by installation of these structures supplemented stream corridors by supporting large numbers of inv...
Erosion Control for Local Roads
Minnesota, University of
Triangular Silt Dikes Chapter 6 - Sediment Control During Construction . . . 5 7 Biorolls Inlet Protection Perimeter Control Sediment Basins Sediment Traps Silt Curtain Silt Fence Standpipes Treatment Basins - NURP
Aging effects of environmental factors on rolled erosion control productsĀ
Khanna, Sumee
This thesis presents a study made on erosion control blankets with respect to their aging and longevity. Erosion control blankets have been relied upon increasingly in recent times replacing the old and traditional methods ...
Geospatial application of the Water Erosion Prediction Project (WEPP) model
Technology Transfer Automated Retrieval System (TEKTRAN)
The Water Erosion Prediction Project (WEPP) model is a process-based technology for prediction of soil erosion by water at hillslope profile, field, and small watershed scales. In particular, WEPP utilizes observed or generated daily climate inputs to drive the surface hydrology processes (infiltrat...
The comparison of various approach to evaluation erosion risks and design control erosion measures
NASA Astrophysics Data System (ADS)
Kapicka, Jiri
In the present is in the Czech Republic one methodology how to compute and compare erosion risks. This methodology contain also method to design erosion control measures. The base of this methodology is Universal Soil Loss Equation (USLE) and their result long-term average annual rate of erosion (G). This methodology is used for landscape planners. Data and statistics from database of erosion events in the Czech Republic shows that many troubles and damages are from local episodes of erosion events. An extent of these events and theirs impact are conditional to local precipitation events, current plant phase and soil conditions. These erosion events can do troubles and damages on agriculture land, municipally property and hydro components and even in a location is from point of view long-term average annual rate of erosion in good conditions. Other way how to compute and compare erosion risks is episodes approach. In this paper is presented the compare of various approach to compute erosion risks. The comparison was computed to locality from database of erosion events on agricultural land in the Czech Republic where have been records two erosion events. The study area is a simple agriculture land without any barriers that can have high influence to water flow and soil sediment transport. The computation of erosion risks (for all methodology) was based on laboratory analysis of soil samples which was sampled on study area. Results of the methodology USLE, MUSLE and results from mathematical model Erosion 3D have been compared. Variances of the results in space distribution of the places with highest soil erosion where compared and discussed. Other part presents variances of design control erosion measures where their design was done on based different methodology. The results shows variance of computed erosion risks which was done by different methodology. These variances can start discussion about different approach how compute and evaluate erosion risks in areas with different importance.
7 CFR 3201.68 - Erosion control materials.
Code of Federal Regulations, 2014 CFR
...2014-01-01 2014-01-01 false Erosion control materials. 3201.68 Section...PROCUREMENT Designated Items ¦ 3201.68 Erosion control materials. (a) Definition...or other sites to prevent wind or water erosion of loose earth surfaces, which may...
7 CFR 3201.68 - Erosion control materials.
Code of Federal Regulations, 2013 CFR
...2013-01-01 2013-01-01 false Erosion control materials. 3201.68 Section...PROCUREMENT Designated Items ¦ 3201.68 Erosion control materials. (a) Definition...or other sites to prevent wind or water erosion of loose earth surfaces, which may...
7 CFR 3201.68 - Erosion control materials.
Code of Federal Regulations, 2012 CFR
...2012-01-01 2012-01-01 false Erosion control materials. 3201.68 Section...PROCUREMENT Designated Items ¦ 3201.68 Erosion control materials. (a) Definition...or other sites to prevent wind or water erosion of loose earth surfaces, which may...
Technology Transfer Automated Retrieval System (TEKTRAN)
Even though new models, such as WEPS, simulate wind erosion processes, one must still rely upon the model user to optimize the design of control systems. In this report, we suggest how processes can influence selection and design of erosion controls. When macro roughness is not fully armored, larg...
Fallout radionuclide-based techniques for assessing the impact of soil conservation measures on erosion control and soil quality: an overview of the main lessons learnt under an FAO/IAEA Coordinated Research Project.
Dercon, G; Mabit, L; Hancock, G; Nguyen, M L; Dornhofer, P; Bacchi, O O S; Benmansour, M; Bernard, C; Froehlich, W; Golosov, V N; Haciyakupoglu, S; Hai, P S; Klik, A; Li, Y; Lobb, D A; Onda, Y; Popa, N; Rafiq, M; Ritchie, J C; Schuller, P; Shakhashiro, A; Wallbrink, P; Walling, D E; Zapata, F; Zhang, X
This paper summarizes key findings and identifies the main lessons learnt from a 5-year (2002-2008) coordinated research project (CRP) on "Assessing the effectiveness of soil conservation measures for sustainable watershed management and crop production using fallout radionuclides" (D1.50.08), organized and funded by the International Atomic Energy Agency through the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture. The project brought together nineteen participants, from Australia, Austria, Brazil, Canada, Chile, China, Japan, Morocco, Pakistan, Poland, Romania, Russian Federation, Turkey, United Kingdom, United States of America and Vietnam, involved in the use of nuclear techniques and, more particularly, fallout radionuclides (FRN) to assess the relative impacts of different soil conservation measures on soil erosion and land productivity. The overall objective of the CRP was to develop improved land use and management strategies for sustainable watershed management through effective soil erosion control practices, by the use of ╣│?Cs (half-life of 30.2 years), ▓╣?Pb(ex) (half-life of 22.3 years) and ?Be (half-life of 53.4 days) for measuring soil erosion over several spatial and temporal scales. The environmental conditions under which the different research teams applied the tools based on the use of fallout radionuclides varied considerably--a variety of climates, soils, topographies and land uses. Nevertheless, the achievements of the CRP, as reflected in this overview paper, demonstrate that fallout radionuclide-based techniques are powerful tools to assess soil erosion/deposition at several spatial and temporal scales in a wide range of environments, and offer potential to monitor soil quality. The success of the CRP has stimulated an interest in many IAEA Member States in the use of these methodologies to identify factors and practices that can enhance sustainable agriculture and minimize land degradation. PMID:22336567
Robotic weld overlay coatings for erosion control
NASA Astrophysics Data System (ADS)
Levin, B. F.; Dupont, J. N.; Marder, A. R.
Research is being conducted to develop criteria for selecting weld overlay coatings for erosion mitigation in circulated fluidized beds. Twelve weld overlay alloys were deposited on 1018 steel substrates using plasma arc welding. Ten samples from each coating were prepared for erosion testing. All selected coatings were erosion tested at 400C and their erosion resistance and microstructure evaluated. Steady state erosion rates were similar for several weld overlay coatings (Ultimet, Inconel-625, Iron-Aluminide, 316L SS, and High Chromium Cast Iron) and were considerably lower than the remaining coating evaluated. These coatings had different base (Co, Fe, Ni-base). No correlations were found between room temperature microhardness of the weld overlay coatings and their erosion resistance at elevated temperature, although this criteria is often thought to be an indicator of erosion resistance. It was suggested that the coatings that showed similar erosion rates may have similar mechanical properties such as fracture strength, toughness and work hardening rates at this temperature. During the past quarter, Iron-Aluminide, Inconel-625, and 316L SS coatings were selected for more detailed investigations based upon the preliminary erosion test results. Microhardness tests were performed on eroded samples to determine the size of the work hardened zone and change in coatings hardness due to erosion. The work hardened zone was correlated with erosion resistance of the coatings. Additional Iron-Aluminide, Inconel-625, and 316L SS coatings were deposited on 1018 steel substrates.
Geospatial application of the Water Erosion Prediction Project (WEPP) model
Technology Transfer Automated Retrieval System (TEKTRAN)
At the hillslope profile and/or field scale, a simple Windows graphical user interface (GUI) is available to easily specify the slope, soil, and management inputs for application of the USDA Water Erosion Prediction Project (WEPP) model. Likewise, basic small watershed configurations of a few hillsl...
Poplars and willows for soil erosion control in New Zealand
A. G Wilkinson
Poplars (Populus) and willows (Salix) are exotic to New Zealand and have been introduced and cultivated over the last 160 years, for soil erosion control on pastoral hill country, riverbank protection, shade, windbreaks and woodlot forestry. During the 1960s and 1970s over two million poplars were planted in government-subsidised erosion control schemes. Planting techniques and patterns are discussed. This type
18 CFR 1304.202 - General sediment and erosion control provisions.
Code of Federal Regulations, 2014 CFR
...2014-04-01 false General sediment and erosion control provisions. 1304.202 Section... ¦ 1304.202 General sediment and erosion control provisions. (a) During construction...activities, TVA shall require that appropriate erosion and sediment control measures be...
18 CFR 1304.202 - General sediment and erosion control provisions.
Code of Federal Regulations, 2013 CFR
...2012-04-01 true General sediment and erosion control provisions. 1304.202 Section... ¦ 1304.202 General sediment and erosion control provisions. (a) During construction...activities, TVA shall require that appropriate erosion and sediment control measures be...
18 CFR 1304.202 - General sediment and erosion control provisions.
Code of Federal Regulations, 2012 CFR
...2012-04-01 false General sediment and erosion control provisions. 1304.202 Section... ¦ 1304.202 General sediment and erosion control provisions. (a) During construction...activities, TVA shall require that appropriate erosion and sediment control measures be...
18 CFR 1304.202 - General sediment and erosion control provisions.
Code of Federal Regulations, 2011 CFR
...2011-04-01 false General sediment and erosion control provisions. 1304.202 Section... ¦ 1304.202 General sediment and erosion control provisions. (a) During construction...activities, TVA shall require that appropriate erosion and sediment control measures be...
NSDL National Science Digital Library
PALS-Performance Assessment Links in Science
Students will design and conduct an open-ended investigation using a variety of earth materials to answer a question posed by the teacher: How does the erosion of sand compare with the erosion of gravel? After producing evidence that addresses this question, they will generate their own question that could be answered with further scientific inquiry.
International Erosion Control Association www.ieca.org
Ma, Lena
, agricultural science, or marine science.) Applicant must have a cumulative undergraduate GPA of 2.75 (on a 4.0. Applicant must have a career direction related to the erosion and sediment control industry. (Possible
Approaches to controlling erosion in rural areas
George Fleming
The intensive utilization of rural areas for the settlement of expanding populations and for the increased production of food and timber can lead to acute sediment erosion problems when careful planning is not implemented. The conservation of soil resources, while at the same time permitting their maximum developŁ ment for man, calls for research which integrates all the factors relating
Implementation of Channel-Routing Routines in the Water Erosion Prediction Project (WEPP) Model
Technology Transfer Automated Retrieval System (TEKTRAN)
The Water Erosion Prediction Project (WEPP) model is a process-based, continuous-simulation, watershed hydrology and erosion model. It is an important tool for water erosion simulation owing to its unique functionality in representing diverse landuse and management conditions. Its applicability is l...
Cover crops for erosion control in bioenergy hardwood plantations
Malik, R.K.; Green, T.H.; Mays, D. [Alabama A& M Univ., Normal, AL (United States)] [and others
The use of cover crops between tree rows has been suggested as a means of reducing soil erosion in short-rotation woody crops (SRWC) plantations for bioenergy production. This study is designed to test whether cover crops could reduce erosion without significantly reducing the growth and biomass yield of sweetgum (Liquidambar styraciflua L.) planted as the SRWC at a 1.5 X 3 in spacing. Four cover crops, winter rye grass (Lolium multigeonum L., a winter annual grass); tall fescue (Fescuta eliator L., a winter perennial grass); crimson clover (Trifolium incarnatum L., a winter annual legume); and interstate sericea (Lespedeza ameata L., a growing season perennial legume), are tested at two different strip widths (1.22 and 2.44 m) as well as a control with complete competition control. Small berms were built to direct runoff to a sediment fence installed at the down slope ends of each plot. Soil erosion is measured by sediment accumulation near the fence. Height, ground-line diameter and crown width of trees were measured on a monthly basis. During the first growing season all cover crops reduced growth of trees. There were some significant differences among cover crop regimes. Slight differences in soil erosion were detected during the first growing season. The control plots lost more soil per hectare than cover crops, however, strip widths and cover crops did not show any significant difference.
A comparison of erosion and water pollution control strategies for an agricultural watershed
Tony Prato; Hongqi Shi
The effectiveness and efficiency of two erosion control strategies and one water pollution control (riparian) strategy are compared for Idaho's Tom Beall watershed. Erosion control strategies maximize annualized net returns per hectare on each field and restrict field erosion rates to no more than 11.2 or 16.8 tons per hectare. The riparian strategy uses good vegetative cover on all fields
The Daily Erosion Project - lessons learned by expanding a statewide erosion and runoff model beyond state boundaries
NASA Astrophysics Data System (ADS)
Gelder, Brian; James, David; Herzmann, Daryl; Scott, Victoria; Cruse, Richard; Laflen, John; Flanagan, Dennis; Frankenberger, Jim; Opsomer, Jean
The Daily Erosion Project (DEP) model is an extension of the Iowa Daily Erosion Project (IDEP) 2.0 model to additional states in the US, initially Kansas and Minnesota. DEP provides comprehensive and dynamic estimates of sediment delivery, soil erosion, and hill slope runoff for agricultural land areas across the area of interest. The integration of high spatial and temporal resolution precipitation and climate data, high resolution LiDAR topography, spatially variable soil properties from current SSURGO information, remotely sensed crop rotation and residue management data, provides increased spatial resolution of runoff and erosion estimates over IDEP 1.0, the previous version derived from land management survey data. The reasoning used to define a representative measurement unit, subcatchments of Hydrologic Unit Code (HUC) 12 watersheds (each approximately 1000 hectares) throughout the modeled area along with methods used to incorporate disparate LiDAR datasets as well as varying crop rotations and management practices and their effects on model accuracy will be discussed.
Water Erosion Prediction Project (WEPP) ¢Development History, Model Capabilities and Future Enhancements
Technology Transfer Automated Retrieval System (TEKTRAN)
The Water Erosion Prediction Project (WEPP) was initiated in August 1985 to develop new generation water erosion prediction technology for use by federal agencies involved in soil and water conservation and environmental planning and assessment. Developed by USDA-ARS as a replacement for empirically...
Erosion control on steep slopes following pipeline construction
Zellmer, S.D.; Taylor, J.D.; Conte, D.J.; Gaynor, A.J.
Replicated plots to compare the effectiveness of eight erosion-control methods, representing a wide range of economic cost, were established during cleanup operations over the pipeline and on the working side of an ROW on a 23% slope in southwestern Pennsylvania. Precipitation, runoff volume, and sediment yield were determined for 45 precipitation events, and vegetative cover was measured by the point-intercept method four times during the 18-month study. Differences in sediment yield were observed between eight erosion-control methods tested and their ROW locations, but total plant cover was not influenced by method or location. The combination of material and installation costs for each method was estimated. Combined economic and environmental data indicated straw mulch at 3.35 Mg ha/sup -1/ (1.5 ton acre/sup -1/) was the most effective of the methods tested. 9 refs., 6 tabs.
System and method for controlling erosion of a shoreline
Ingersoll, R.W.
This patent describes a system for controlling erosion of the slope between the waterline of a shoreline. The system comprises an elongated conduit; means to pivotably secure the conduit to the shoreline approximately at the waterline; a plurality of individual armor bags attached to the conduit; and means for filling all of the individual armor bags with a grout material whereby the armor bags when filled with the grout material will be positioned as a unit onto the slope below the waterline.
Soil Erosion and Sediment Production on Watershed Landscapes: Processes and Control
Soil Erosion and Sediment Production on Watershed Landscapes: Processes and Control Authors: Peter Erosion and Sediment Production on Watershed Landscapes: Processes, Prevention, and Control #12;Authors, Scientific and Cultural Organizations (UNESCO). ISBN 978-92-9089-190-1- Soil Erosion and Sediment Production
Control of Eolian soil erosion from waste site surface barriers
Ligotke, M.W.
Physical models were tested in a wind tunnel to determine optimum surface-ravel admixtures for protecting silt-loam soil from erosion by, wind and saltating, sand stresses. The tests were performed to support the development of a natural-material surface barrier for and waste sites. Plans call for a 2-m deep silt-loam soil reservoir to retain infiltrating water from rainfall and snowmelt. The objective of the study was to develop a gravel admixture that would produce an erosion-resistant surface layer during, periods of extended dry climatic stress. Thus, tests were performed using simulated surfaces representing dry, unvegetated conditions present just after construction, after a wildfire, or during an extended drought. Surfaces were prepared using silt-loam soil mixed with various grades of sand and Travel. Wind-induced surface shear stresses were controlled over the test surfaces, as were saltating, sand mass flow rates and intensities. Tests were performed at wind speeds that approximated and exceeded local 100-year peak gust intensities. Surface armors produced by pea gravel admixtures were shown to provide the best protection from wind and saltating sand stresses. Compared with unprotected silt-loam surfaces, armored surfaces reduced erosion rates by more than 96%. Based in part on wind tunnel results, a pea gravel admixture of 15% will be added to the top 1 in of soil in a prototype barrier under construction in 1994. Field tests are planned at the prototype site to provide data for comparison with wind tunnel results.
Global carbon export from the terrestrial biosphere controlled by erosion.
Galy, Valier; Peucker-Ehrenbrink, Bernhard; Eglinton, Timothy
Riverine export of particulate organic carbon (POC) to the ocean affects the atmospheric carbon inventory over a broad range of timescales. On geological timescales, the balance between sequestration of POC from the terrestrial biosphere and oxidation of rock-derived (petrogenic) organic carbon sets the magnitude of the atmospheric carbon and oxygen reservoirs. Over shorter timescales, variations in the rate of exchange between carbon reservoirs, such as soils and marine sediments, also modulate atmospheric carbon dioxide levels. The respective fluxes of biospheric and petrogenic organic carbon are poorly constrained, however, and mechanisms controlling POC export have remained elusive, limiting our ability to predict POC fluxes quantitatively as a result of climatic or tectonic changes. Here we estimate biospheric and petrogenic POC fluxes for a suite of river systems representative of the natural variability in catchment properties. We show that export yields of both biospheric and petrogenic POC are positively related to the yield of suspended sediment, revealing that POC export is mostly controlled by physical erosion. Using a global compilation of gauged suspended sediment flux, we derive separate estimates of global biospheric and petrogenic POC fluxes of 157(+74)(-50) and 43(+61)(-25) megatonnes of carbon per year, respectively. We find that biospheric POC export is primarily controlled by the capacity of rivers to mobilize and transport POC, and is largely insensitive to the magnitude of terrestrial primary production. Globally, physical erosion rates affect the rate of biospheric POC burial in marine sediments more strongly than carbon sequestration through silicate weathering. We conclude that burial of biospheric POC in marine sediments becomes the dominant long-term atmospheric carbon dioxide sink under enhanced physical erosion. PMID:25971513
A Comparison of Erosion and Water Pollution Control Strategies for an Agricultural Watershed
NASA Astrophysics Data System (ADS)
Prato, Tony; Shi, Hongqi
The effectiveness and efficiency of two erosion control strategies and one water pollution control (riparian) strategy are compared for Idaho's Tom Beall watershed. Erosion control strategies maximize annualized net returns per hectare on each field and restrict field erosion rates to no more than 11.2 or 16.8 tons per hectare. The riparian strategy uses good vegetative cover on all fields adjacent to the creek and in noncropland areas and the resource management system that maximizes annualized net returns per hectare on remaining fields. The Agricultural Nonpoint Source Pollution model is used to simulate the levels and concentrations of sediment, nitrogen, phosphorus, and chemical oxygen demand at the outlet of the watershed. Erosion control strategies generate less total erosion and water pollution but are less efficient than the riparian strategy. The riparian strategy is less equitable for farmers than the erosion control strategies.
Wetland Platform Erosion by Wave Action and its Implications for Future Mitigation Projects in South Louisiana
NASA Astrophysics Data System (ADS)
Wilson, C.; Allison, M.
The transition of marshland to open water in south Louisiana continues at an alarming rate, and freshwater diversions and marsh restoration projects have been implemented or are planned to address this loss. This project examines the magnitude and impact of wave-induced subaqueous platform erosion that occurs during and following subsidence of the subaerial marsh. Study and control sites have been chosen in Breton Sound, where an existing freshwater diversion project (Caernarvon) has been operational since 1991; Barataria Bay, where the Davis Pond diversion has been active since 2003; and the Deltas National Wildlife Refuge (DNWR), where marshes are still receiving significant freshwater and sediment from the Mississippi River. Study grids are established along marsh fringes in bay-fronting, gulf-fronting, and interior ponds that have a variety of orientations and open water fetch to predominant wave attack and in recent years (since the 1930s) have shown significant wetland loss. Subaqueous platform elevation and stratigraphy are examined with vibracores and transit elevation transects and detailed bathymetric maps of the 1 km grids are also made with an Odom Hydrotrak HT100 fathometer. Preliminary results suggest that the overall magnitude of wave-induced erosion is extreme (deflation of 1-1.5 m) in Barataria Bay sites, but may not be as great a magnitude in Breton Sound or the DNWR sites. Shoreline orientation to wave attack, the composition and resistance to wave re-working of the underlying sediment, or the presence of submerged aquatic vegetation (SAV) that serves to stabilize the substrata may help explain the resultant site to site variability. Predominant in many sites, once the aerial marsh has submerged, a portion of the peat deposits is preserved below more recent onlapping bay bottom sediments.
Shoreline erosion control structure: Application of wastewater sludge ash
Hannan, A.; Khanbilvardi, R.M.
Disposal of sludge from sewage treatment plant presents a rapidly growing problem in metropolitan areas in the US. Approximately 1,000 dry tons of sludge per day is disposed of in New York State alone. Incineration of sludge is a common practice to reduce its volume, however the final ash remaining for disposal after the burning process is considerably high. This paper details the outcome of the laboratory and field studies those were conducted to evaluate the suitability of incinerator ash as an aggregate for use in shoreline erosion control structure. The field study was done for twelve months. In the field study 108 ash mixed blocks were compared with 108 non-ash blocks. Every month 9 ash blocks and 9 non-ash blocks were taken out from the bay for chemical and physical tests. The results show that the ash blocks behaved just like the non-ash blocks. No adverse environmental impacts were observed. So, ash can be used in making blocks, which can be used, for shoreline erosion structures.
Field studies of beach cones as coastal erosion control/reversal devices for areas with significant oil and gas activities. Technical progress report, April--June 1992 and Project status report, June 1992
Not Available
A field demonstration/study of a novel shoreline erosion protection device called beach cones is planned. These patented, fiberglass- reinforced concreted devices are to be deployed in a number of geometric patterns at seven location in the Bastian Bay area of Western Plaquemines Parish. The purpose of the work described in this report was to evaluate the proposed study`s impact on living and non-living shellfish resources within each of the project`s seven separate Study Areas. Major accomplishments for this reporting period were as follows: aerial photographs of the experimental sites were taken; all permit applications were filed; information was submitted for the Environmental Report; several reconnaissance trips to the experimental sites were made; meetings were held among all participating organizations to further plan the research; permit was obtained from the US Army Corps of Engineers; test sites were surveyed by the Xavier University contingent; survey data were taken at all sites; the Oyster Assessment was completed; permit was obtained from the State of Louisiana Department of Natural Resources; and initial survey data were finalized at all sites.
Beach erosion control study at Pass Christian. [using remote sensors and satellite observation
NASA Technical Reports Server (NTRS)
The methods of measuring the existence of erosion and the effects of sand stabilization control systems are described. The mechanics of sand movement, the nature of sand erosion, and the use of satellite data to measure these factors and their surrogates are discussed using the locational and control aspects of aeolian and litoral erosion zones along the sand beach of the Mississippi coast. The aeolian erosion is highlighted due to the redeposition of the sand which causes high cleanup costs, property damage, and safety and health hazards. The areas of differential erosion and the patterns of beach sand movement are illustrated and the use of remote sensing methods to identify the areas of erosion are evaluated.
76 FR 68745 - Notice of Intent To Update the Upland Erosion Control and Revegetation and Maintenance Plan and...
Federal Register 2010, 2011, 2012, 2013, 2014
...Erosion Control and Revegetation and Maintenance Plan and the Wetland and Waterbody Construction and Mitigation Procedures and Request...Erosion Control, Revegetation and Maintenance Plan (Plan) and Wetland and Waterbody Construction and Mitigation Procedures...
Technology Transfer Automated Retrieval System (TEKTRAN)
The Water Erosion Prediction Project (WEPP) model is a process-based, distributed parameter, continuous simulation computer program for estimation of runoff, soil loss and sediment yield from fields and small watersheds. In addition to having large databases for application to a multitude of U.S. s...
Robotic weld overlay coatings for erosion control. Quarterly technical progress report, January 1994--March 1994
Levin, B.F.; Dupont, J.N.; Marder, A.R.
The erosion of materials by the impact of solid particles has received increasing attention during the past twenty years. Recently, research has been initiated with the event of advanced coal conversion processes in which erosion plays an important role. The resulting damage, termed Solid Particle Erosion (SPE), is of concern primarily because of the significantly increased operating costs which result in material failures. Reduced power plant efficiency due to solid particle erosion of boiler tubes and waterwalls has led to various methods to combat SPE. One method is to apply coatings to the components subjected to erosive environments. Protective weld overlay coatings are particularly advantageous in terms of coating quality. The weld overlay coatings are essentially immune to spallation due to a strong metallurgical bond with the substrate material. By using powder mixtures, multiple alloys can be mixed in order to achieve the best performance in an erosive environment. However, a review of the literature revealed a lack of information on weld overlay coating performance in erosive environments which makes the selection of weld overlay alloys a difficult task. The objective of this project is to determine the effects of weld overlay coating composition and microstructure on erosion resistance. These results will lead to a better understanding of erosion mitigation in circulated fluidized beds.
Technology Transfer Automated Retrieval System (TEKTRAN)
Use of anionic polyacrylamide (PAM) as an erosion control soil amendment has been studied at the USDA-ARS National Soil Erosion Research Lab since the early 1990's. An initial field experiment in Indiana using simulated rainfall on a sloping silt loam soil found that 20 kg ha-1 of PAM could reduce s...
Use of calliandra¢Napier grass contour hedges to control erosion in central Kenya
S. D. Angima; D. E. Stott; M. K. OÆNeill; C. K. Ong; G. A. Weesies
Contour hedgerow systems consisting of various combinations of tree and grass species can be used on sloping lands to minimize erosion, restore fertility, and improve crop productivity, but there is need to evaluate the effectiveness of each system for its suitability at any locality as effective erosion control. The objectives of this study were to determine the amount of soil
Control and evaluation of particle impact conditions in a sand erosion test facility
Y. I Oka; M Nishimura; K Nagahashi; M Matsumura
For the prediction of actual damage to plant component materials and for making the erosion mechanisms clear, it is important to control and to evaluate the particle impact conditions in a testing facility. A sand blast type erosion test rig, which can achieve the particle impact velocities up to 135ms?1 and a wide range of impact angles has been constructed.
Controls on erosion intensity in the Yangtze River basin tracked by UPb detrital zircon dating
Clift, Peter
Controls on erosion intensity in the Yangtze River basin tracked by UŁPb detrital zircon dating May 2014 Available online 29 May 2014 Keywords: Yangtze River Sediments Detrital zircons Erosion. In this study we used UŁPb dating of zircon grains from the modern main stream and major tributaries to identify
Does Rock Mass Strength Control the Rate of Alpine Cliff Erosion?
NASA Astrophysics Data System (ADS)
Moore, J. R.; Sanders, J. W.; Dietrich, W. E.; Glaser, S. D.
Collapse of cliff faces by rockfall is a primary mode of bedrock erosion in alpine environments and plays a controlling role in mass removal from these systems. In this work we investigate the influence of rock mass strength on the retreat rate of alpine rock slopes. To quantify rockwall competence we employed the Slope Mass Rating (SMR) geomechanical strength index, which combines numerous factors that affect the strength of a rock mass, such as intact rock strength, joint frequency, joint condition, and more. The magnitude of cliff retreat was calculated by estimating the volume of talus at the toe of each rockwall and projecting that material back onto the cliff face, while accounting for the loss of production area as talus buries the base of the wall. Selecting sites within basins swept clean by advancing LGM glaciers allowed us to estimate the time period over which talus accumulation occurred (i.e. the production time). Dividing the magnitude of normal cliff retreat by the production time, we calculated erosion rates for each site. Our study area included a portion of the Sierra Nevada from Yosemite National Park in the south to Lake Tahoe in the north. Rockwall recession rates determined for 40 alpine cliffs in this region varied from 0.02 to 1.22 mm/year, with an average value of 0.28 mm/year. We found good correlation between rockwall recession rate and SMR that is best characterized by an exponential decrease in erosion rate with increasing rock mass strength. Analysis of the individual components of the SMR reveals that joint orientation (with respect to the cliff face) is the most important parameter affecting the rockwall erosion rate. The complete SMR score, however, best synthesizes the lithologic variables that contribute to the strength and erodibility of these rock slopes. Our data reveal no strong independent correlation between the measured rockwall retreat rate and environmental attributes (such as site elevation, aspect, cliff slope length, and cliff slope angle), suggesting that rock mass strength is the dominant parameter controlling the rate of cliff erosion in our study area.
Hardin, D.S. [Bechtel Savannah River Inc., Savannah River Site, Aiken, SC (United States); Carnes, W.S. [Westinghouse Savannah River Co., Aiken, SC (United States)
Project management controls are utilized to enhance the probability that a project will be successful. The control system used by a project manager can take many forms and can be applied at different times to varying degrees on a given project depending upon its complexity. The Consolidated Incineration Facility (CIF) is one project of many at the Savannah River Site (SRS). The United States Department of Energy Order 4700.1 is a project management system that is applied on a site-wide basis, thus including the CIF. The control system required by this order is proceduralized to ensure that it is applied in a consistent manner and will produce reliable results. These results provide the project manager with a correlation of both costs and schedule within the defined scope to adequately asses the status of the project. This is an iterative process and can be simply stated: plan, actual, variance, corrective action, prediction, and revision. This paper presents the basis for the project management controls applied at the Savannah River Site.
Hardin, D.S. (Bechtel Savannah River Inc., Savannah River Site, Aiken, SC (United States)); Carnes, W.S. (Westinghouse Savannah River Co., Aiken, SC (United States))
Project management controls are utilized to enhance the probability that a project will be successful. The control system used by a project manager can take many forms and can be applied at different times to varying degrees on a given project depending upon its complexity. The Consolidated Incineration Facility (CIF) is one project of many at the Savannah River Site (SRS). The United States Department of Energy Order 4700.1 is a project management system that is applied on a site-wide basis, thus including the CIF. The control system required by this order is proceduralized to ensure that it is applied in a consistent manner and will produce reliable results. These results provide the project manager with a correlation of both costs and schedule within the defined scope to adequately asses the status of the project. This is an iterative process and can be simply stated: plan, actual, variance, corrective action, prediction, and revision. This paper presents the basis for the project management controls applied at the Savannah River Site.
Bedload transport controls intra-event bedrock erosion
NASA Astrophysics Data System (ADS)
Beer, A. R.; Turowski, J. M.
Fluvial bedrock incision constrains the pace of mountainous landscape evolution. Fluvial erosion processes have been described with incision models that are widely applied in river reach and catchment scale studies. However, so far, no linked field data set at the process scale had been published that allows to assess model requirements and adequacy. Here, we evaluate the predictive power of various incision models on data on hydraulics, bedload transport and erosion recorded on an artificial bedrock slab installed in a steep mountain stream for a single bedload transport event. The influence of transported bedload on erosion rate (the "tools effect") is shown to be dominant while other effects are of minor importance. Hence, a simple temporal distributed incision model in which erosion rate is proportional to bedload transport rate is proposed for transient local studies. This model can be site-calibrated with temporally lumped bedload and erosion data and its applicability can be assessed by visual inspection of the study site. Basic discharge-based models like derivatives of the stream power model family however, are adequate to reproduce the overall trend of the observed erosion rate, at least for the event on hand. This is relevant for long-term studies of e.g. landscape evolution with no interest in transient local behaviour.
Gullying and erosion control 507 Copyright 2006 John Wiley & Sons, Ltd. Earth Surf. Process. Landforms 31, 507525 (2006)
Pederson, Joel L.
Gullying and erosion control 507 Copyright ® 2006 John Wiley & Sons, Ltd. Earth Surf. Process Gullying and erosion control at archaeological sites in Grand Canyon, Arizona Joel L. Pederson1 *, Paul A, USA Abstract Gully erosion of cultural sites in Grand Canyon National Park is an urgent management
NSDL National Science Digital Library
Richard A. McLaughlin
This homepage of Dr. Richard A. McLaughlin at North Carolina State University includes a four-part tutorial about soil erosion and mitigation. Slide presentations include an introduction to the factors that lead to soil erosion, a general discussion of soil characteristics and susceptibility to erosion, an overview of the formation of rills and gullies, and some examples of sediment transport dynamics and erosion reduction techniques. The site also features short videos that show tests of erosion control methods in an artificial environment.
Stubble Mulch Management for Water Conservation and Erosion Control on Hardlands of the Southern Great Plains.
Johnson, Wendell C. (Wendell Clifford); Van Doren, C. E.; Whitfield, Charles J. (Charles James)
LIBRARY A; & k!. COLl EGF f STUBBLE MULCH MANAGEMENT for Water Conservation and Erosion Control on Hardlands of the Southern Great Plains in cooperation with the UNITED STATES DEPARTMENT OF AGRICULTURE [Blank Page in Original Bulletin... STUBBLE MULCH MANAGEMENT For Water Conservation and Erosion Control Hardlands the Southern Great Plains CHARLES J. WHITFIELD, C. E. VAN DOREN and WENDELL JOHNSON* L EARNING to farm the heavy soils of the Southern Great Plains successfully has been...
Technology Transfer Automated Retrieval System (TEKTRAN)
The Water Erosion Prediction Project (WEPP) model was tested using data from a detailed field-scale study conducted on experimental plots in the Apennines Mountain Range, Northern Italy. Runoff, soil water and sediment data, together with weather information, were automatically collected on a contin...
George M. Kaminsky; Guy Gelfenbaum
The Southwest Washington Coastal Erosion Study is a five-year, multi-disciplinary research project designed to build a knowledge foundation as a sound basis for addressing coastal management objectives. The purpose of the Study is to gain an understanding of a regional coastal sediment system, the Columbia River littoral cell, in order to support local, state, and federal decision-making in land-use planning,
Device Oriented Project Controller
Dalesio, Leo; Kraimer, Martin
This proposal is directed at the issue of developing control systems for very large HEP projects. A de-facto standard in accelerator control is the Experimental Physics and Industrial Control System (EPICS), which has been applied successfully to many physics projects. EPICS is a channel based system that requires that each channel of each device be configured and controlled. In Phase I, the feasibility of a device oriented extension to the distributed channel database was demonstrated by prototyping a device aware version of an EPICS I/O controller that functions with the current version of the channel access communication protocol. Extensions have been made to the grammar to define the database. Only a multi-stage position controller with limit switches was developed in the demonstration, but the grammar should support a full range of functional record types. In phase II, a full set of record types will be developed to support all existing record types, a set of process control functions for closed loop control, and support for experimental beam line control. A tool to configure these records will be developed. A communication protocol will be developed or extensions will be made to Channel Access to support introspection of components of a device. Performance bench marks will be made on both communication protocol and the database. After these records and performance tests are under way, a second of the grammar will be undertaken.
The contribution of mulches to control high soil erosion rates in vineyards in Eastern Spain
NASA Astrophysics Data System (ADS)
CerdÓ, Artemi; Jordßn, Antonio; Zavala, Lorena; Josķ Marquķs, MarĒa; Novara, Agata
Soil erosion take place in degraded ecosystem where the lack of vegetation, drought, erodible parent material and deforestation take place (Borelli et al., 2013; Haregeweyn et al., 2013; Zhao et al., 2013). Agriculture management developed new landscapes (Ore and Bruins, 2012) and use to trigger non-sustainable soil erosion rates (Zema et al., 2012). High erosion rates were measured in agriculture land (CerdÓ et al., 2009), but it is also possible to develop managements that will control the soil and water losses, such as organic amendments (Marquķs et al., 2005), plant cover (Marquķs et al., 2007) and geotextiles (Gimķnez Morera et al., 2010). The most successful management to restore the structural stability and the biological activity of the agriculture soil has been the organic mulches (GarcĒa Orenes et al; 2009; 2010; 2012). The straw mulch is also very successful on bare fire affected soil (Robichaud et al., 2013a; 2013b), which also contributes to a more stable soil moisture content (GarcĒa-Moreno et al., 2013). The objective of this research is to determine the impact of two mulches: wheat straw and chipped branches, on the soil erosion rates in a rainfed vineyard in Eastern Spain. The research site is located in the Les Alcusses Valley within the Moixent municipality. The Mean annual temperature is 13 ║C, and the mean annual rainfall 455 mm. Soil are sandy loam, and are developed at the foot-slope of a Cretaceous limestone range, the Serra Grossa range. The soils use to be ploughed and the features of soil erosion are found after each thunderstorm. Rills are removed by ploughing. Thirty rainfall simulation experiments were carried out in summer 2011 during the summer drought period. The simulated rainfall lasted during 1 hour at a 45 mmh-1 intensity on 1 m2 plots (CerdÓ and Doerr, 2010; CerdÓ and Jurgensen 2011). Ten experiments were carried out on the control plots (ploughed), 10 on straw mulch covered plots, and 10 on chipped branches covered soil. The results show that the soil erosion is reduced by 10 on straw mulch covered soils and by 4 on chipped branches covered soil. Acknowledgements The research projects GL2008-02879/BTE, LEDDRA 243857 and RECARE supported this research. References Borrelli, P., Mõrker, M., Sch³tt, B. 2013. Modelling post-tree-haversting soil erosion and sediment deposition potential in the Turano River Basin (Italian Central Apennine). Land Degradation & Development, DOI 10.1002/ldr.2214 CerdÓ, A., Flanagan, D.C., le Bissonnais, Y., Boardman, J. 2009. Soil erosion and agriculture Soil and Tillage Research 106, 107-108. DOI: 10.1016/j.still.2009.1 CerdÓ, A., Morera, A.G., BodĒ, M.B. 2009. Soil and water losses from new citrus orchards growing on sloped soils in the western Mediterranean basin. Earth Surface Processes and Landforms 34, 1822-1830. GarcĒa-Moreno, J., Gordillo-Rivero, ┴.J., Zavala, L.M., Jordßn, A., Pereira, P. 2013. Mulch application in fruit orchards increases the persistence of soil water repellency during a 15-years period. Soil and Tillage Research 130, 62-68. GarcĒa-Orenes, F., CerdÓ, A., Mataix-Solera, J., Guerrero, C., BodĒ, M.B., Arcenegui, V., Zornoza, R. & Sempere, J.G. 2009. Effects of agricultural management on surface soil properties and soil-water losses in eastern Spain. Soil and Tillage Research 106, 117-123. 10.1016/j.still.2009.06.002 GarcĒa-Orenes, F., Guerrero, C., Roldßn, A.,Mataix-Solera, J., CerdÓ, A., Campoy, M., Zornoza, R., Bßrcenas, G., Caravaca. F. 2010. Soil microbial biomass and activity under different agricultural management systems in a semiarid Mediterranean agroecosystem. Soil and Tillage Research 109, 110-115. 10.1016/j.still.2010.05.005. GarcĒa-Orenes, F., Roldßn, A., Mataix-Solera, J., CerdÓ, A., Campoy, M., Arcenegui, V., Caravaca, F. 2012. Soil structural stability and erosion rates influenced by agricultural management practices in a semi-arid Mediterranean agro-ecosystem. Soil Use and Management 28, 571-579. DOI: 10.1111/j.1475-2743.2012.00451.x Gimķnez Morera, A., Ruiz Sinoga, J.D. y CerdÓ, A.
Technology Transfer Automated Retrieval System (TEKTRAN)
Fish were sampled by backpack electroshocker from Little Topashaw Creek, MS to evaluate the effectiveness of bank stabilization structures constructed of large woody debris in reducing erosion and improving aquatic habitat. Specific details of project design and of physical habitat and morphology o...
Agriculture and stream water quality: A biological evaluation of erosion control practices
David R. Lenat
Agricultural runoff affects many streams in North Carolina. However, there is is little information about either its effect on stream biota or any potential mitigation by erosion control practices. In this study, benthic macroinvertebrates were sampled in three different geographic areas of North Carolina, comparing control watersheds with well-managed and poorly managed watersheds. Agricultural streams were characterized by lower taxa
Environmental evaluation of flue gas desulfurization gypsum as a BMP for erosion control
Technology Transfer Automated Retrieval System (TEKTRAN)
Flue Gas Desulfurization Gypsum (FGDG) is produced from pollution control systems reducing sulfur dioxide emissions from thermo-electric coal-fired power plants. Natural gypsum and FGDG both have been shown to be useful in control of soil erosion. However, concerns have been raised recently by envir...
An improved spark erosion machine control unit for cutting of hard metals
G. N. Payne
A control circuit for a wire spark erosion machine for precise cutting of hard metals is described. It is well suited to construction by a small electronics laboratory and the description includes all safety and cut-out controls that are required.
Erosion risk assessment of controlled burning of grasses established on steep slopes
NASA Astrophysics Data System (ADS)
Gyasi-Agyei, Yeboah
It is a standard practice to establish grasses on steep slopes (batters) of embankments and cuttings to minimise erosion problems. However, the increase in grass density (high biomass) on the steep slopes poses a greater risk of fire. Controlled burning is a common fuel hazard reduction program employed to minimise the fire risks. The increased risk of erosion on the steep slopes after controlled burning has received little attention if any. This paper assesses the erosion risks associated with controlled burning of grasses established on steep slopes. Grasses, with and without the aid of waste ballast rock mulch, were established on 10 m wide railway embankment batter experiment plots. Two-and-a-half years after the grass establishment, selected plots were controlled burned. Runoff and soil loss from the experimental plots were monitored throughout the 3Į-year period of the experiment. After one year the grass cover on the burned plots has hardly exceeded 60%, far below the average pre-burn levels of about 80%. All treatments achieved an incredible soil loss reduction of over 95% (compared with the bare scenario) without controlled burning at the end of the 3Į-year period. This percentage value was decreased numerically by 14 where controlled burning was implemented. Compared with the 100% grass cover treatment, runoff rates tripled while erosion rates increased by nine-fold for the waste ballast treatment, and 17-fold for the non-waste ballast treatment, during the first year following controlled burning.
US Army Corps of Engineers
TRUCKEE MEADOWS FLOOD CONTROL PROJECT, NEVADA DRAFT GENERAL REEVALUATION REPORT May 2013 #12;#12;Truckee Meadows Flood Control Project, Nevada Draft General Reevaluation Report May 2013 Prepared by U Meadows Flood Control Project, Nevada 5/15/2013 Draft General Reevaluation Report EXECUTIVE SUMMARY
Er:YAG laser irradiation to control the progression of enamel erosion: an in situ study.
Scatolin, R S; Colucci, V; Lepri, T P; Alexandria, A K; Maia, L C; Galo, R; Borsatto, M C; Corona, S A M
This in situ study evaluated the effect of Er:YAG laser irradiation in controlling the progression of enamel erosion-like lesions. Fifty-six enamel slabs (330 KHN?▒?10Ā%) with one fourth of the surface covered with resin composite (control area) were submitted to initial erosion-like lesion formation with citric acid. The slabs were divided into two groups: irradiated with Er:YAG laser and non-irradiated. Fourteen volunteers used an intraoral palatal appliance containing two slabs, in two phases of 5Ādays each. During the intraoral phase, in a crossed-over design, half of the volunteers immersed the appliance in citric acid while the other half used deionized water, both for 5Āmin, three times per day. Enamel wear was determined by an optical 3D profilometer. ANOVA revealed that when deionized water was used as immersion solution during the intraoral phase, lower values of wear were showed when compared with the groups that were eroded with citric acid, whether irradiated or non-irradiated with Er:YAG laser. When erosion with citric acid was performed, Er:YAG laser was not able to reduce enamel wear. Small changes on enamel surface were observed when it was irradiated with Er:YAG laser. It may be concluded that Er:YAG laser irradiation did not reduce the progression of erosive lesions on enamel submitted to in situ erosion with citric acid. PMID:24985348
Erosion control on a steeply sloped pipeline right-of-way in southwestern Pennsylvania
Zellmer, S.D.; Edgar, D.E. (Argonne National Lab., IL (USA)); Isaacson, H.R. (Gas Research Inst., Chicago, IL (USA))
The results of precipitation on steeply sloped pipeline rights-of-way (ROWs) during the time between ROW rehabilitation and the establishment of a dense, self-sustaining vegetative ground cover can cause locally severe soil erosion. This erosion results in elevated sediment loads in receiving streams and increases the difficulty and costs of ROW maintenance. A field study was completed that compared the environmental effectiveness of nine treatments on a 28% ROW slope in southwestern Pennsylvania. The six erosion-control methods investigated in the study, selected to represent a wide range in material type and installation cost, were (1) heavy application of straw mulch, (2) light application of straw mulch, (3) processed wood fiber, (4) chemical soil binder, (5) paper strips in netting, and (6) light straw mulch with a tacking agent. Each of the test plots also received the basic treatment of limestone, fertilizer, and a seed mixture commonly used to rehabilitate ROWs in the region. Precipitation, runoff volumes, and sediment yields were measured on each of 51 plots for 45 precipitation events during the 18-month study. Vegetation data were collected by the point-intercept method four times during the study to determine the amount of plant cover and species composition. Differences in sediment yield were observed among methods and between ROW location, but plant cover development was not influenced by erosion-control method or location. The relationship between environmental and cost data indicated that, of the six erosion-control methods tested, a light application of straw mulch was the most effective erosion-control treatment. 19 refs., 2 figs., 6 tabs.
Comprehensive Erosion and Sediment Control Training Program for Engineers, Architects and Planners.
ERIC Educational Resources Information Center
Porter, Harry L., Jr.
This program training text was designed to provide uniform instruction to the engineer, architect, planner, and others who will be helping to implement an erosion and sediment control program. Although tailored for use in Virginia, the basic principles covered are universal, and the material is adaptable to meet the needs in any State. The 11ģ
Does Rock Mass Strength Control the Rate of Alpine Cliff Erosion?
J. R. Moore; J. W. Sanders; W. E. Dietrich; S. D. Glaser
Collapse of cliff faces by rockfall is a primary mode of bedrock erosion in alpine environments and plays a controlling role in mass removal from these systems. In this work we investigate the influence of rock mass strength on the retreat rate of alpine rock slopes. To quantify rockwall competence we employed the Slope Mass Rating (SMR) geomechanical strength index,
An Economic Analysis of USDA Erosion Control Programs: A New Perspective. Agricultural Economic Report No. 560.
ERIC Educational Resources Information Center
Strohbehn, Roger, Ed.
A study analyzed the total (public and private) economic costs and benefits of three U.S. Department of Agriculture erosion control programs. These were the Conservation Technical Assistance Program, Great Plains Conservation Program, and Agricultural Conservation Program. Significant efforts at funding for current programs were directed toģ
Erosion control practices integrated with polyacrylamide for nutrient reduction in rill irrigation runoff
Technology Transfer Automated Retrieval System (TEKTRAN)
The objective of this research was to assess soil conservation practices for improving water quality of return flows from rill irrigation in the Yakima River Basin, Washington, by combining patch application of polyacrylamide (PAM) with an additional erosion control practice. A two-year field study ...
Technology Transfer Automated Retrieval System (TEKTRAN)
The erosion control effectiveness of no-till(NT) crops and grass buffer strips studies at MAFES, Holly Springs, MS on idle land being returned to row-crop production provided useful information related to the potential return to row-crop production of land previously in the conservation reserve prog...
Soil erosion and sediment control laws. A review of state laws and their natural resource data requirements
NASA Technical Reports Server (NTRS)
Klein, S. B.
Twenty states, the District of Columbia, and the Virgin Islands enacted erosion and sediment control legislation during the past decade to provide for the implementation or the strengthening of statewide erosion and sediment control plans for rural and/or urban lands. That legislation and the state programs developed to implement these laws are quoted and reviewed. The natural resource data requirements of each program are also extracted. The legislation includes amendments to conservation district laws, water quality laws, and erosion and sediment control laws. Laws which provides for legislative review of administrative regulations and LANDSAT applications and/or information systems that were involved in implementing or gathering data for a specific soil erosion and sediment control program are summarized as well as principal concerns affecting erosion and sediment control laws.
Coastal erosion and sea level rise: Implications for ocean beach and San Francisco's westside transport project
Peter J. Wilcoxen
One of the consequences of sea level rise resulting from the greenhouse effect is increased coastal erosion. This article discusses a model of erosion that can be used to estimate the response of beaches to sea level rise. The model is applied to Ocean Beach, California, with particular attention to the consequences of accelerated erosion for the San Francisco Westside
Chosing erosion control nets. Can't you decide? Ask the lab.
NASA Astrophysics Data System (ADS)
Simkova, Jana; Jacka, Lukas
Geotextiles (GTXs) have been used to protect steep slopes against soil erosion for about 60 years and many products have become available. The choice of individual product is always based on its ratio of cost versus effectiveness. Generally applicable recommendations for specific site conditions are missing and testing the effectiveness of GTXs in the field is time consuming and costly. Due to various site conditions, results of numerous case-studies cannot be generalized. One of the major and site-specific factors affecting the erosion process, and hence the effectiveness of GTXs, is the soil. This study aimed to determine the rate of influence of three natural erosion control nets on the volume and velocity of surface runoff caused by rainfall. The nets were installed on slope under laboratory conditions and then exposed to simulated rainfall. An impermeable plastic film was used as a substrate instead of soil to simulate non-infiltrating conditions. A comparison of the influence of tested GTX samples on surface runoff may indicate to their erosion control effect. Thus, the results could help with choosing a particular product. Under real conditions, the effect of erosion control nets would be increased by the infiltration capacity of the soil, equally for all samples. Therefore, the order of effectiveness of the samples should stay unchanged. To validate this theory, a field experiment was carried out where soil loss was recorded along with runoff characteristics. The data trends of discharge culmination under natural conditions were similar to trends under laboratory conditions and corresponded to soil loss records.
Tempo-spatial downscaling of multiple GCMs projections for soil erosion risk analysis at El Reno, Oklahoma, USA
Technology Transfer Automated Retrieval System (TEKTRAN)
Proper spatial and temporal treatments of climate change scenarios projected by General Circulation Models (GCMs) are critical to accurate assessment of climatic impacts on natural resources and ecosystems. For accurate prediction of soil erosion risk at a particular farm or field under climate cha...
Sedimentation in three small erosion control reservoirs in northern Mississippi
Technology Transfer Automated Retrieval System (TEKTRAN)
The water storage capacity and dam integrity of thousands of flood control reservoirs built since 1950 are potentially compromised by excessive impounded sediments. The fate of these structures depends on the amount and characteristics of this accumulated material. To aid in understanding the scop...
Controlled ultrasound tissue erosion: The role of dynamic interaction between insonation and microbubble activity
Xu, Zhen; Fowlkes, J. Brian; Rothman, Edward D.; Levin, Albert M.; Cain, Charles A.
Previous studies showed that ultrasound can mechanically remove tissue in a localized, controlled manner. Moreover, enhanced acoustic backscatter is highly correlated with the erosion process. ōInitiationö and ōextinctionö of this highly backscattering environment were studied in this paper. The relationship between initiation and erosion, variability of initiation and extinction, and effects of pulse intensity and gas saturation on time to initiation (initiation delay time) were investigated. A 788-kHz single-element transducer was used. Multiple pulses at a 3-cycle pulse duration and a 20-kHz pulse repetition frequency were applied. ISPPA values between 1000 and 9000 W/cm2 and gas saturation ranges of 24%¢28%, 39%¢49%, and 77%¢81% were tested. Results show the following: (1) without initiation, erosion was never observed; (2) initiation and extinction of the highly backscattering environment were stochastic in nature and dependent on acoustic parameters; (3) initiation delay times were shorter with higher intensity and higher gas saturation (e.g., the mean initiation delay time was 66.9 s at ISPPA of 4000 W/cm2 and 3.6 ms at ISPPA of 9000 W/cm2); and (4) once initiated by high-intensity pulses, the highly backscattering environment and erosion can be sustained using a significantly lower intensity than that required to initiate the process. PMID:15704435
Coastal erosion and sea level rise: implications for Ocean Beach and San Francisco's Westside Transport Project
Wilcoxen, P.J.
One of the consequences of sea level rise resulting from the greenhouse effect is increased coastal erosion. This article discusses a model of erosion that can be used to estimate the response of beaches to sea level rise. The model is applied to Ocean Beach, California, with particular attention to the consequences of accelerated erosion for the San Francisco Westside Sewer Transport. Results obtained show that erosion produced by accelerated sea level rise could cause substantial damage to the structure. Large expenditures on beach nourishment will be required to protect the transport and recreational value of the beach. 12 references, 9 figures, 5 tables.
Managing the Arroyo Seco for Flood Prevention, Erosion Control, Waterway and Habitat Restoration
Sanchez, L; Wang, C; Laurant, J
One of the most important tasks for a site facility manager is to ensure that appropriate channel erosion controls are applied to on-site drainage channels. These erosion controls must minimize risks to the public and structures. Water and sediment loads commonly originate from off-site sources and many of the traditional reactionary measures (installing rip-rap or some other form of bed or bank armor) simply transfer or delay the problem. State and federal agency requirements further complicate the management solution. One case in point is the Arroyo Seco, an intermittent stream that runs along the southwest corner of the Lawrence Livermore National Laboratory (LLNL) in Livermore, California. In 2001, LLNL contracted Questa Engineering Corporation to conduct hydraulic, geomorphic, and biological investigations and to prepare an alternatives and constraints analysis. From these investigations, LLNL has selected a water management plan that encompasses overall flood prevention, erosion control, and waterway and habitat restoration and enhancement elements. The most unique aspect of the Arroyo Seco management plan is its use of non-traditional and biotechnical techniques.
[Mechanisms of grass in slope erosion control in Loess sandy soil region of Northwest China].
Zhao, Chun-Hong; Gao, Jian-En; Xu, Zhen
By adopting the method of simulated precipitation and from the viewpoint of slope hydrodynamics, in combining with the analysis of soil resistance to erosion, a quantitative study was made on the mechanisms of grass in controlling the slope erosion in the cross area of wind-water erosion in Loess Plateau of Northwest China under different combinations of rainfall intensity and slope gradient, aimed to provide basis to reveal the mechanisms of vegetation in controlling soil erosion and to select appropriate vegetation for the soil and water conservation in Loess Plateau. The grass Astragalus adsurgens with the coverage about 40% could effectively control the slope erosion. This grass had an efficiency of more than 70% in reducing sediment, and the grass root had a greater effect than grass canopy. On bare slope and on the slopes with the grass plant or only the grass root playing effect, there existed a functional relation between the flow velocity on the slopes and the rainfall intensity and slope gradient (V = DJ(0.33 i 0.5), where V is flow velocity, D is the comprehensive coefficient which varies with different underlying surfaces, i is rainfall intensity, and J is slope gradient). Both the grass root and the grass canopy could markedly decrease the flow velocity on the slopes, and increase the slope resistance, but the effect of grass root in decreasing flow velocity was greater while the effect in increasing resistance was smaller than that of grass canopy. The effect of grass root in increasing slope resistance was mainly achieved by increasing the sediment grain resistance, while the effect of canopy was mainly achieved by increasing the slope form resistance and wave resistance. The evaluation of the soil resistance to erosion by using a conceptual model of sediment generation by overland flow indicated that the critical shear stress value of bare slope and of the slopes with the grass plant or only the grass root playing effect was 0.533, 1.672 and 0.925 Pa, respectively. PMID:23717998
Assessment of the role of bottomland hardwoods in sediment and erosion control
Molinas, A.; Auble, Gregor T.; Segelquist, C.A.; Ischinger, Lee S.
Drainage and clearing of bottomland hardwoods have long been recognized by the U.S. Environmental Protection Agency (EPA) and the U.S. Fish and Wildlife Service (Service) as important impacts of Federal water projects in the lower Mississippi River Valley. More recently, the water quality impacts of such projects (e.g., increases in sediments, nutrients, and pesticides) have also become of concern. In 1984, in an effort to better define problems concerning wetland losses and water degradation, EPA initiated a cooperative project with the Western Energy and Land Use Team (now the National Ecology Research Center) of the Service. Three phases of the project were identified: 1. To collect existing literature and data; 2. To select, develop, and test the utility of methods to quantify the relationships between land use, cover types, soils, hydrology, and water quality (as represented by sediment); and 3. To apply selected methodologies to several sites within the Yazoo Basin of Mississippi to determine the, potential effectiveness of various management alternatives to reduce sediment yield, increase sediment deposition, and improve water quality. Methods development focused on linking a simulation of water and sediment movement to a computerized geographic information system. We had several objectives for the resulting model. We desired that it should: 1. Estimate the importance of bottomland and hardwoods as a cover type that performs the functions of erosion and sediment control, 2. Simulate effects of proportions of ' various cover types and their specific spatial configurations, 3. Be applicable to moderately large spatial areas with minimal site-specific calibration, 4. Simulate spatial patterns of sediment loss-gain over time, and 5. Represent both sediment detachment and transport. While it was recognized that impacts and management alternatives could be sorted roughly into landscape measures and channel measures, the decision was made to focus study efforts mainly on landscape measures. Landscape measures include altered drainage and flooding patterns, altered cover types (e.g., conversion of bottomland hardwoods to agricultural crops, reforestation of cropland to bottomland hardwoods, and creation of riparian buffer strips), altered cropping and tillage patterns, altered routing of water, and creation of buffer strips along wetlands and channel margins. Channel measures include vegetative bank stabilization, grade control structures, and regulation of channel water volume and velocity. During the first year of the study, EPA decided not to fund the third phase of the project. This required considerable rescoping of the project with the result that application of the sediment mobilization, routing, and deposition models to various management alternatives and portions of the Yazoo Basin was somewhat restricted. We believe, however, that this report will provide a good understanding of the various modes of sediment mobilization, transport, and deposition within the Yazoo Basin, as well as of the role of bottomland hardwoods. The model developed in this study could be applied to a variety of management or mitigation alternatives prior to implementation to determine their relative effectiveness. Policy, political, and socio-economic consequences of any proposed management/mitigation practice, however, must ultimately be taken into consideration by those charged with management of water resources within the Yazoo Basin before any practice is implemented. This study makes no effort to judge the feasibility of management alternatives in this regard.
Biodiversity in riverbank techniques for erosion control: assessment of animal and plant species diversity along a natural gradient.
Paris-Sud XI, Universitķ de
Biodiversity in riverbank techniques for erosion control: assessment of animal and plant species * Corresponding author: firstname.lastname@example.com Keywords: beetles, biodiversity, ecological restoration, plant.). However, whether such installations can accommodate natural biodiversity has not been well assessed
Meta-analysis of the effects of plant roots in controlling concentrated flow erosion rates
NASA Astrophysics Data System (ADS)
Vannoppen, Wouter; Poesen, Jean; Vanmaercke, Matthias; De Baets, Sarah
Vegetation is often used in ecological restoration programs to control various soil erosion processes. During the last two decades several studies reported on the effects of plant roots in controlling concentrated flow erosion rates. However a global analysis of the now available data on root effects is still lacking. Yet, a meta-data analysis will contribute to a better understanding of the soil-root interactions as our capability to assess the effectiveness of roots in reducing soil erosion rates due to concentrated flow in different environments remains difficult. The objectives of this study are therefore i) to provide a state of the art on studies quantifying the effectiveness of roots in reducing soil erosion rates due to concentrated flow; and ii) to explore the overall trends in erosion reduction as a function of the root (length) density, root system architecture and soil texture, based on a global analysis of published research data. We therefore compiled a dataset of measured relative soil detachment rates (RSD) for the root density (RD; 822 observations) as well as the root length density (RLD; 274 observations). Non-linear regression analyses showed that decreases in RSD as a function of RD and RLD could be best described with the Hill curve model. However, a large proportion of the variability in RSD could not be attributed to RD or RLD, resulting in a relatively low predictive accuracy of the Hill curve model with model efficiencies of 0.11 and 0.17 for RD and RLD respectively. Considering root architecture and soil texture yielded a better predictive model especially for RLD with ME of 0.37 for fibrous roots in a non-sandy soil. The unexplained variance is to a large extent attributable to measuring errors and differences in experimental set ups that could not be explicitly accounted for (e.g. tested plant species, soil and flow characteristics). However, using a Monte Carlo simulation approach, we were able to establish relationships that allow assessing the likely erosion-reducing effects of plant roots, while taking these uncertainties into account. Our analyses further showed that compared to RD, RLD is a much more suitable variable to estimate RSD, because it is indirectly correlated to root system architecture.
Project test plan for runoff and erosion on fine-soil barrier surfaces and rock-covered side slopes
Walters, W.H.; Hoover, K.A.; Cadwell, L.L.
Pacific Northwest Laboratory (PNL) and Westinghouse Hanford Company are working together to develop protective barriers to isolate near-surface radioactive waste. The purpose of the barriers is to protect defense wastes at the US Department of Energy's (DOE) Hanford Site from infiltration of precipitation, biointrusion, and surficial erosion for up to 10,000 years without the need for long-term monitoring, maintenance, or institutional control. The barriers will be constructed of layered earth and rock material designed to direct surface and groundwater pathways away from the buried waste. To address soil erosion as it applies to barrier design and long-term stability, a task designed to study this problem has been included in the Protective Barriers Program at PNL. The barrier soil-erosion task will investigate the ability of the soil cover and side slopes to resist the erosional and destabilizing processes from externally applied water. The study will include identification and field testing of the dominant processes contributing to erosion and barrier failure. The effects of rock mulches, vegetation cover on the top fine-grained soil surface, as well as the stability of rock armoring on the side slopes, will be evaluated. Some of the testing will include the effects of animal intrusion on barrier erosion, and these will be coordinated with other animal intrusion studies. 6 refs., 4 figs., 1 tab.
Quality Control Mini Culture Project
Vardeman, Stephen B.
IE 361 Quality Control Mini Culture Project "ROBUST ENGINEERING" For: Dr. Vardeman By: Jason as the products quality get farther away from the target value. The traditional control limits were defined main types of quality in a product. These types are (1) customer quality and (2) engineered quality
Costs and benefits of urban erosion and sediment control: The North Carolina experience
NASA Astrophysics Data System (ADS)
Paterson, Robert G.; Luger, Michael I.; Burby, Raymond J.; Kaiser, Edward J.; Malcom, H. Rooney; Beard, Alicia C.
The EPAÆs new nonpoint source pollution control requirements will soon institutionalize urban erosion and sediment pollution control practices nationwide. The public and private sector costs and social benefits associated with North CarolinaÆs program (one of the strongest programs in the country in terms of implementation authority, staffing levels, and comprehensiveness of coverage) are examined to provide general policy guidance on questions relating to the likely burden the new best management practices will have on the development industry, the likely costs and benefits of such a program, and the feasibility of running a program on a cost recovery basis. We found that urban erosion and sediment control requirements were not particularly burdensome to the development industry (adding about 4% on average to development costs). Public-sector program costs ranged between 2.4 and 4.8 million in fiscal year 1989. Our contingent valuation survey suggests that urban households in North Carolina are willing to pay somewhere between 7.1 and 14.2 million a year to maintain current levels of sediment pollution control. Our benefit-cost analysis suggests that the overall ratio is likely to be positive, although a definitive figure is elusive. Lastly, we found that several North Carolina localities have cost recovery fee systems that are at least partially self-financing.
Project resources planning and control
NASA Technical Reports Server (NTRS)
Sibbers, C. W.
This report contains instructional guidelines for the resources planning and control of research and development (R&D) projects managed by NASA's Langley Research Center (LaRC). Although written to serve primarily as a practical guide and reference for those LaRC personnel who perform resources planning, analysis, control, and reporting functions, it should also be meaningful to other NASA personnel who are directly or indirectly involved in or affected by these functions, especially project technical managers whose responsibilities include resources management. Certain sections should help Contractor personnel to better understand what resources information must usually be submitted on LaRC projects and what use is made of such information. The Project Manager of a large R&D project typicaly receives support from an Analyst in the area of resources management. The Analyst provides assistance in four functional areas: Planning, Analysis/Control, Administration, and Reporting. Each of these functions are discussed in detail. Examples of techniques used effectively on LaRC projects have been included where applicable. A considerable amount of information has been included on the use of Performance Measurement (Earned Value) Systems for contract cost control and reporting as little information is currently available on this subject in NASA publications.
Direct and indirect impacts of climate change on soil erosion and land degradation in Mediterranean watersheds: a presentation of the ERLAND project
NASA Astrophysics Data System (ADS)
Nunes, JoŃo. Pedro; Corte-Real, JoŃo.; Keizer, Jan Jacob; Abrantes, Nelson; Cķsar Lima, J·lio; Roebeling, Peter; Sampaio, Elsa; Santos, JoŃo.; Eufķmia Varela, Maria
This presentation will describe the recently-approved ERLAND project (2010-2013), whose main aim is to estimate the impacts of climate change on soil erosion in representative Portuguese agroforestry watersheds, due to changes in rainfall, runoff generation and vegetation cover. Soil erosion is a critical driver for desertification in Mediterranean regions, degrading the soil's capacity to sustain vegetation under marginal climatic conditions. An increase in climatic aridity, caused by global climate change, could lead to increases or decreases in erosion, depending on the interaction between lower rainfall and lower vegetation biomass productivity The main objective of ERLAND is to characterize the most important impacts climate change could cause on different erosive processes within Mediterranean catchments, and help define the costs and benefits of different adaptation options. The project explicitly addresses important limitations of similar past studies, such as: (i) lack of appropriate downscaling of climate change scenarios; (ii) focus on hillslope or, in rare instances, channel processes, ignoring gully erosion; or (iii) lack of sufficient erosion data for the proper evaluation of the erosion models used in these assessments. The main analysis tool will be a new vegetation, runoff and erosion model, built by joining together existing and widely tested concepts to simulate vegetation, hydrology and erosion. It will aim at the continuous simulation of sediment detachment and transport within catchments, using a detailed simulation of spatial patterns while simplifying the simulation of temporal patterns, allowing for a multi-year application. The project will focus on two catchments, corresponding to typical combinations of climate and land cover/use under humid and dry climate conditions: in northern Portugal, eucalypt/pine commercial forestry combined with annual cultures or vineyards; in southern Portugal, extensive cork oak forestry (montado) associated with annual cultures or pastures. Data on climate, vegetation, hydrology and soil erosion will be collected at different spatial scales (hillslope, gullies, catchment), to allow for a correct calibration of the model in simulating the most important erosive processes for current conditions. Climate change scenarios for 2071-2100 will be downscaled for the study areas based on existing regional climate models through a statistical approach. Results are expected to provide insights on the erosive impacts of changes in key erosive factors, i.e.: rainfall regime, vegetation cover (including increased wildfire frequency), soil moisture and hydrological regimes. Impacts will be assessed in terms of soil loss at the slope scale, gully erosion processes and catchment sediment yield. Scenarios for land-use change and agroforestry adaptation due to climate change will also be developed and tested using the model. ERLAND will represent one of the few studies performed for Mediterranean conditions, and explicitly including gully erosion and sediment connectivity.
Erosion controls on the metamorphic core complex dynamics and its relationship with syn- rift basin evolution
NASA Astrophysics Data System (ADS)
Wang, Kun; Burov, Evgueni; Gumiaux, Charles; Chen, Yan; Zhao, Liang
The wide rifting evolves towards asymmetric extensional thinning of the entire crust and development of different characteristic features such as basins, half-grabens and metamorphic core complexes (MCC). In this context, formation of supra-detachment basins is also a common feature, along with the exhumation of metamorphic rocks and considerable displacements along the hanging wall. Initiation, geometry and mechanisms of metamorphic core complexes have been already largely debated on the basis field observations, analog and numerical models. For example, it has been well demonstrated that strain softening favors asymmetric deformation and accounts for different styles of brittle and ductile strain localization. However, the temporal and spatial relations between the dome formation and basin evolution are still poorly understood. In particular, most of the existing numerical models predict a topographical depression above the metamorphic dome, whereas in nature dome formation often corresponds to a topographical uplift. To explain these phenomena, we have integrated surface erosion, sedimentary processes and strain softening into a state-of-the-art 2-D numerical thermo-mechanical model of MCC development. In the numerical experiments, we first reproduce formation of a univergent MCC by implementing strain softening and testing a large spectrum of lithospheric structures. In the next series of experiments we apply erosion/sedimentation and test model sensitivity to different erosion parameters. The results show two distinctive stages of MCC dynamics and syn-rift basin development. One single broad basin forms above the dome and is divided onto an inactive basin located at the distal detachment and an active supradetachment basin that deepens with further extension, characterized by crustal necking and dome amplificationduring the MCC formation. It is noteworthy that without strain softening, erosion at of the rift flanks mayresult in complete burial of the dome below the sedimentary cover. The experiments also demonstrate strong dependence of the system evolution on the initial thermo-rheological structure. The geometry and topography of the rift system is largely controlled by syn-extensional erosion that also strongly affects vertical and lateral movements during the rifting phase. The predicted rift dynamics can be compared to the case of the wide rift system of the eastern part of North China Craton.
Ecosystem services in Mediterranean river basin: climate change impact on water provisioning and erosion control.
Bangash, Rubab F; Passuello, Ana; Sanchez-Canales, MarĒa; Terrado, Marta; L¾pez, Alfredo; Elorza, F Javier; Ziv, Guy; Acu±a, Vicenń; Schuhmacher, Marta
The Mediterranean basin is considered one of the most vulnerable regions of the world to climate change and such changes impact the capacity of ecosystems to provide goods and services to human society. The predicted future scenarios for this region present an increased frequency of floods and extended droughts, especially at the Iberian Peninsula. This paper evaluates the impacts of climate change on the water provisioning and erosion control services in the densely populated Mediterranean Llobregat river basin of. The assessment of ecosystem services and their mapping at the basin scale identify the current pressures on the river basin including the source area in the Pyrenees Mountains. Drinking water provisioning is expected to decrease between 3 and 49%, while total hydropower production will decrease between 5 and 43%. Erosion control will be reduced by up to 23%, indicating that costs for dredging the reservoirs as well as for treating drinking water will also increase. Based on these data, the concept for an appropriate quantification and related spatial visualization of ecosystem service is elaborated and discussed. PMID:23660520
Materials for Advanced Turbine Engines (MATE). Project 4: Erosion resistant compressor airfoil coating
NASA Technical Reports Server (NTRS)
Rashid, J. M.; Freling, M.; Friedrich, L. A.
The ability of coatings to provide at least a 2X improvement in particulate erosion resistance for steel, nickel and titanium compressor airfoils was identified and demonstrated. Coating materials evaluated included plasma sprayed cobalt tungsten carbide, nickel carbide and diffusion applied chromium plus boron. Several processing parameters for plasma spray processing and diffusion coating were evaluated to identify coating systems having the most potential for providing airfoil erosion resistance. Based on laboratory results and analytical evaluations, selected coating systems were applied to gas turbine blades and evaluated for surface finish, burner rig erosion resistance and effect on high cycle fatigue strength. Based on these tests, the following coatings were recommended for engine testing: Gator-Gard plasma spray 88WC-12Co on titanium alloy airfoils, plasma spray 83WC-17Co on steel and nickel alloy airfoils, and Cr+B on nickel alloy airfoils.
Potential controls of alluvial bench deposition and erosion in southern Piedmont streams, Alabama (USA)
NASA Astrophysics Data System (ADS)
Haney, Nicholas R.; Davis, Lisa
Benches are bank-attached channel deposits occurring at an elevation between the channel bed and top of banks. Their occurrence in a variety of geologic and hydrologic settings has led to confusion about the mechanisms driving their formation, which in turn contributes to difficulty identifying the active floodplain, bankfull stage, and the determination of environmental flows in some rivers. Hydrodynamic modeling software (River 2D), in combination with sediment particle size analysis and total station topographic surveys, was used to simulate flow conditions needed to erode and deposit the D84, D50, and D15 particle sizes of concave and lateral benches in two rivers (Talladega and Hillabee creeks) in Alabama. Results suggest that bench erosion requires flows at least 150% larger than benchfull stage at the Talladega site, while the Hillabee site experienced erosion at all discharges meeting and exceeding benchfull flow stage, likely owing to its overall smaller sediment particle sizes. At both sites, the presence of vegetation increased the bench area subjected to deposition but, somewhat counterintuitively, also helped influence the location of erosion by limiting flow vectors. In contrast with previous research findings, the occurrence of reverse flow was neither sustained nor widespread at either site. These findings provide new insight into alluvial benches, suggest that the study benches are relatively stable features under the prevailing hydrologic regime, and that in some temperate climate settings, such as the southern Piedmont, localized hydraulic controls on bench formation can be superseded in importance by hydrologic flow regime, even in the case of concave benches and where flow regulation is not a factor.
Influence of Gully Erosion Control on Amphibian and Reptile Communities Within Riparian Zones of Channelized Streams
Technology Transfer Automated Retrieval System (TEKTRAN)
Riparian zones of streams in northern Mississippi have been impacted by agriculture, channelization, channel incision, and gully erosion. Gully erosion is the most severe form of erosion and has resulted in the fragmentation of remnant riparian zones within agricultural watersheds. One widely used c...
Influence of gully erosion control on amphibian and reptile communities within riparian zones of channelized streams
Technology Transfer Automated Retrieval System (TEKTRAN)
Riparian zones of streams in northern Mississippi have been impacted by agriculture, channelization, channel incision, and gully erosion. Gully erosion is the most severe form of erosion and has resulted in the fragmentation of remnant riparian zones within agricultural watersheds. One widely used c...
Fluor Fernald - Project Controls Process
This paper will look at the project controls process Fluor has developed to ensure cleanup can be declared and verified by the contract in the shortest time possible. In November 2000 the Department of Energy and Fluor Fernald entered into a closure contract that incentivized Fluor Fernald to reduce the cost and schedule of the cleanup. Original schedule estimates to
Fluor Fernald - Project Controls Process
Reed, C.W. [Fluor Fernald, Inc., P.O. Box 538704, Cincinnati, OH 45253 (United States)
This paper will look at the project controls process Fluor has developed to ensure cleanup can be declared and verified by the contract in the shortest time possible. In November 2000 the Department of Energy and Fluor Fernald entered into a closure contract that incentivized Fluor Fernald to reduce the cost and schedule of the cleanup. Original schedule estimates to complete the job went well beyond 2010. In 2002 the Department of Energy (DOE) renegotiated the contract with emphasis on completing the cleanup by December 2006. This model for site closure was developed and has worked effectively to move the project through the cleanup phase, to change a culture and set in motion the steps necessary to declare closure and ultimately leave the project in a timely manner. It is Fluor's goal to complete the project safely, ahead of schedule and cost estimates thereby maximizing profit for company shareholders. This paper will demonstrate the successful implementation for an integrated project management system that has been proven and used on the Fluor Fernald project. The objective is to summarize the approach used at Fernald in setting forth those management processes to accelerate schedule and reduce cost while managing the project safely. (authors)
Soil tillage conservation and its effect on erosion control, water management and carbon sequestration
NASA Astrophysics Data System (ADS)
Rusu, Dr.; Gus, Dr.; Bogdan, Dr.; Moraru, Dr.; Pop, Dr.; Clapa, Dr.; Pop, Drd.
The energetic function of the soil expressed through the potential energy accumulated through humus, the biogeochemical function (the circuit of the nutrient elements) are significantly influenced by its hydrophysical function and especially by the state of the bedding- consolidation, soil capacity of retaining an optimal quantity of water, and then its gradual disponibility for plant consumption. The understanding of soil functions and management including nutrient production, stocking, filtering and transforming minerals, water , organic matter , gas circuit and furnishing breeding material, all make the basis of human activity, Earth's past, present and especially future. The minimum tillage soil systems - paraplow, chisel or rotary grape - are polyvalent alternatives for basic preparation, germination bed preparation and sowing, for fields and crops with moderate loose requirements being optimized technologies for: soil natural fertility activation and rationalization, reduction of erosion, increasing the accumulation capacity for water and realization of sowing in the optimal period. By continuously applying for 10 years the minimum tillage system in a crop rotation: corn - soy-bean - wheat - potato / rape, an improvement in physical, hydro-physical and biological properties of soil was observed, together with the rebuilt of structure and increase of water permeability of soil. The minimum tillage systems ensure an adequate aerial-hydrical regime for the biological activity intensity and for the nutrients solubility equilibrium. The vegetal material remaining at the soil surface or superficially incorporated has its contribution to intensifying the biological activity, being an important resource of organic matter. The minimum tillage systems rebuild the soil structure, improving the global drainage of soil which allows a rapid infiltration of water in soil. The result is a more productive soil, better protected against wind and water erosion and needing less fuel for preparing the germination bed. Presently it is necessary a change concerning the concept of conservation practices and a new approach regarding the control of erosion. The real conservation of soil must be expanded beyond the traditional understanding of soil erosion. The real soil conservation is represented by carbon management. We need to focus to another level concerning conservation by focusing on of soil quality. Carbon management is necessary for a complex of matters including soil, water management, field productivity, biological fuel and climatic change. Profound research is necessary in order to establish the carbon sequestration practices and their implementation impact.
Soil tillage conservation and its effect on erosion control, water management and carbon sequestration
NASA Astrophysics Data System (ADS)
Rusu, T.; Gus, P.; Bogdan, I.; Moraru, P.; Pop, A.; Clapa, D.; Pop, L.
The energetic function of the soil expressed through the potential energy accumulated through humus, the biogeochemical function (the circuit of the nutrient elements) are significantly influenced by its hydrophysical function and especially by the state of the bedding- consolidation, soil capacity of retaining an optimal quantity of water, and then its gradual disponibility for plant consumption. The understanding of soil functions and management including nutrient production, stocking, filtering and transforming minerals, water , organic matter, gas circuit and furnishing breeding material, all make the basis of human activity, Earth's past, present and especially future. The minimum tillage soil systems - paraplow, chisel or rotary grape - are polyvalent alternatives for basic preparation, germination bed preparation and sowing, for fields and crops with moderate loose requirements being optimized technologies for: soil natural fertility activation and rationalization, reduction of erosion, increasing the accumulation capacity for water and realization of sowing in the optimal period. By continuously applying for 10 years the minimum tillage system in a crop rotation: corn - soy-bean - wheat - potato / rape, an improvement in physical, hydro-physical and biological properties of soil was observed, together with the rebuilt of structure and increase of water permeability of soil. The minimum tillage systems ensure an adequate aerial-hydrical regime for the biological activity intensity and for the nutrients solubility equilibrium. The vegetal material remaining at the soil surface or superficially incorporated has its contribution to intensifying the biological activity, being an important resource of organic matter. The minimum tillage systems rebuild the soil structure, improving the global drainage of soil which allows a rapid infiltration of water in soil. The result is a more productive soil, better protected against wind and water erosion and needing less fuel for preparing the germination bed. Presently it is necessary a change concerning the concept of conservation practices and a new approach regarding the control of erosion. The real conservation of soil must be expanded beyond the traditional understanding of soil erosion. The real soil conservation is represented by carbon management. We need to focus to another level concerning conservation by focusing on of soil quality. Carbon management is necessary for a complex of matters including soil, water management, field productivity, biological fuel and climatic change.
Cropping systems and control of soil erosion in a Mediterranean environment
NASA Astrophysics Data System (ADS)
Cosentino, Salvatore; Copani, Venera; Testa, Giorgio; Scalici, Giovanni
The research has been carried out over the years 1996-2010 in an area of the internal hill of Sicily region (Enna, c.da Geracello, 550 m a. s. l. 37░ 23' N. Lat, 14░ 21' E. Long) in the center of Mediterranean Sea, mainly devoted to durum wheat cultivation, using the experimental plots, established in 1996 on a slope of 26-28%, equipped to determine surface runoff and soil losses. The establishment consists of twelve plots, having 40 m length and 8 m width. In order to study the effect of different field crop systems in controlling soil erosion in slopes subjected to water erosion, the following systems were studied: permanent crops, tilled annual crops, no-tilled annual crops, set-aside. The used crops were: durum wheat, faba bean, rapeseed, subterranean clover, Italian ryegrass, alfalfa, sweetvetch, moon trefoil, barley, sweet sorghum, sunflower. The results pointed out that the cropping systems with perennial crops allowed to keep low the soil loss, while annual crop rotation determined a high amount of soil loss. Sod seeding showed promising results also for annual crop rotations.
Robotic weld overlay coatings for erosion control. Quarterly progress report, October 1993--December 1993
Levin, B.F.; DuPont, J.N.; Marder, A.R.
Research is being conducted to develop criteria for selecting weld overlay coatings for erosion mitigation in Circulated Fluidized Beds. Twelve weld overlay alloys were deposited on 1018 steel substrates using plasma arc welding. Ten samples from each coating were prepared for erosion testing. All selected coatings were erosion tested at 400C and their erosion resistance and microstructure evaluated. Steady state erosion rates were similar for several weld overlay coatings (Ultimet, Inconel-625, Iron-Aluminide, 316L SS, and High Chromium Cast Iron) and were considerably lower than the remaining coating evaluated. These coatings had different base (Co, Fe, Ni-base). No correlations were found between room temperature microhardness of the weld overlay coatings and their erosion resistance at elevated temperature, although this criteria is often thought to be an indicator of erosion resistance. It was suggested that the coatings that showed similar erosion rates may have similar mechanical properties such as fracture strength, toughness and work hardening rates at this temperature. During the past quarter, Iron-Aluminide, Inconel-625, and 316L SS coatings were selected for more detailed investigations based upon the preliminary erosion test results. Microhardness tests were performed on eroded samples to determine the size of the work hardened zone and change in coatings hardness due to erosion. The work hardened zone was to correlated with erosion resistance of the coatings. Additional Iron-Aluminide, Inconel-625, and 316L SS coatings were deposited on 1018 steel substrates.
Robotic weld overlay coatings for erosion control. Quarterly technical progress report, July--September, 1994
Levin, B.F.; Dupont, J.N.; Marder, A.R.
Research is presently being conducted to develop a criteria for selecting weld overlay coatings for erosion mitigation in Circulated Fluidized Beds. Initially, eleven weld overlay alloys were selected for erosion testing based upon a literature review. All eleven coatings were deposited on 1018 steel substrates using the plasma arc welding process. Ten samples from each coating were prepared for erosion testing. All selected coatings were erosion tested at 400 C and their erosion resistance was evaluated by determining the steady state erosion rate. In addition, the microstructure of each coating was characterized before and after the erosion tests. No correlations were found between room temperature hardness of the weld overlay coatings and their erosion resistance at elevated temperature. It was suggested that weld overlays mechanical properties such as fracture strength, toughness and work hardening rates may contributed to their erosion resistance. During the previous two quarters the microhardness tests were performed on the eroded samples in order to determine the size of the work hardened zone and the change in the coatings hardness due to erosion. As a result of these measurements it was established that one group of coatings deformed plastically, while another did not. In addition, the measurements of the weld overlays microhardness at 400 C were made. The coatings microhardness at 400 C was plotted versus their volume erosion rates. During the last quarter, erosion tests were performed for Inconel-625, 316L SS, and Iron-Aluminide wrought alloys in order to compare their erosion behavior with similar weld overlays. The results of microhardness profile measurements for all weld overlay coatings were analyzed. The factors that contribute to the erosion resistance of the coatings that deformed plastically are discussed in this progress report.
Combined Wind and Water Erosion Modeling
Technology Transfer Automated Retrieval System (TEKTRAN)
Current soil erosion prediction technologies in the United States for water and wind erosion are vastly different. An effort is underway to create a combined process-based water and wind erosion model, based upon the technologies in the USDA Water Erosion Prediction Project (WEPP) and Wind Erosion P...
Altomare, A.; Ma, J.; Guarino, M.P.L.; Cheng, L.; Rieder, F.; Ribolsi, M.; Fiocchi, C.; Biancani, P.; Harnett, K.; Cicala, M.
Background A distinction between symptomatic non-erosive reflux disease (NERD) and erosive esophagitis (EE) patientsis supported by the presence of inflammatory response in the mucosa of EE patients, leading to a damage of mucosal integrity. To explore the underlying mechanism of this difference we assessed inflammatory mediators in mucosal biopsies from EE and NERD patients and compared them to controls. Methods Nineteen NERD patients, fifteen EE patients and sixteen healthy subjects underwent endoscopy after a 3-week washout from PPI or H2 antagonists. Biopsies obtained from the distal esophagus, were examined by quantitative real-time polymerase chain reaction (qPCR) and multiplex ELISA for selected chemokines and lyso-PAF acetyltransferase (LysoPAF-AT), the enzyme responsible for production of platelet activating factor (PAF). Results Expression of LysoPAF-AT and multiple chemokines was significantly increased in mucosal biopsies derived from EE patients, when compared to NERD patients and healthy controls. Upregulated chemokines included interleukin 8, eotaxin-1, -2 and -3, macrophage inflammatory protein-1? (MIP-1?) and monocyte chemoattractant protein-1 (MCP-1). LysoPAF-AT and the chemokine profile in NERD patients were comparable to healthy controls. Conclusions Levels of selected cytokines and Lyso-PAF AT were significantly higher in the esophageal mucosa of EE patients compared to NERD and control patients. This difference may explain the distinct inflammatory response occurring in EE patientsÆ mucosa. In contrast, since no significant differences existed between the levels of all mediators in NERD and control subjects, an inflammatory response does not appear to play a major role in the pathogenesis of the abnormalities found in NERD patients. PMID:22734465
Robotic weld overlay coatings for erosion control. Quarterly technical progress report, October 1994--December 1994
Levin, B.F.; Dupont, J.N.; Marder, A.R.
Research is presently being conducted to develop a criteria for selecting weld overlay coatings for erosion mitigation in Circulated Fluidized Beds. Initially, eleven weld overlay alloys were selected for erosion testing based upon a literature review. All eleven coatings were deposited on 1018 steel substrates using the plasma arc welding process. Ten samples from each coating were prepared for erosion testing. The coating deposition and sample preparation procedures were described in the second quarterly report. All selected coatings were erosion tested at 400{degree}C and their erosion resistance was evaluated by determining the steady state erosion rate. In addition, the microstructure of each coating was characterized before and after the erosion tests. The results of the tests are discussed in the third quarterly report. No correlations were found between room temperature hardness of the weld overlay coatings and their erosion resistance at elevated temperature. During the last quarter tensile tests were performed at 400{degree}C for the Ultimet, Inconel-625, 316L SS, C-22, and Stellite-6 wrought alloys. The erosion tests for these materials at 400{degree}C are in progress. The results of mechanical and erosion tests will be used to correlate mechanical properties of selected wrought alloys such as tensile toughness, ductility, strain hardening coefficient and yield strength to their erosion resistance at 400{degree}C. Also, the erosion behavior of the wrought alloys compared with similar weld alloys will be analyzed. The experimental procedure and results of the tensile tests are presented in this progress report.
Polymer particle erosion controlling drug release. I. Factors influencing drug release and characterization of the release mechanism.
Zuleger, S; Lippold, B C
The present study deals with controlled drug delivery from hydrocolloid tablets by polymer particle erosion. The influence of excipients and formulation factors on the dissolution behaviour of the methyl hydroxyethyl cellulose (MHEC)-tablets is investigated. Linear drug release with low susceptibility to hydrodynamic stress is obtained. The use of drugs with higher solubility leads to a slight acceleration of the release due to the contribution of diffusion to the release process. Higher drug loading and consequently lower polymer content expedites dissolution as well as changes in the tablets' geometry resulting in enlarged release surfaces. Furthermore, alterations of the composition of the dissolution medium affect drug release. However, neither viscosity grade nor the particle size of the polymer or compaction pressure has a marked impact on the dissolution. Investigations to clarify the mechanism of polymer particle erosion include erosion studies and the comparison of different batches of MHEC, of products from different manufacturers and of fibrous trial products. There is evidence that the insoluble fibres within the water soluble MHEC are responsible for the occurrence of polymer particle erosion by disturbing swelling and formation of a thick coherent gel layer and thus, causing erosion of the hydrocolloid tablet with synchronous drug release. PMID:11292550
Multidimensional visualization of project control data
Anthony D. Songer; Benjamin Hays; Christopher North
The construction industry produces voluminous quantitative data. Much of this data is created during the controls phase of projects and relates to cost, schedule, and administrative information. Recent storage and processing advances in computers as well as display capabilities afforded by computer graphics increase the opportunity to monitor projects fundamentally different from existing project control systems. However, changes in project
Robotic weld overlay coatings for erosion control. Quarterly technical progress report, January 1995--March 1995
Levin, B.F.; Dupont, J.N.; Marder, A.R.
Research is presently being conducted to develop a criteria for selecting weld overlay coatings for erosion mitigation in Circulated Fluidized Beds. During the last two quarters tensile tests were performed at 400{degrees}C for the Ultimet, Inconel-625, 316L SS, C-22, and Stellite-6 wrought alloys. Also, the erosion tests for these materials at 400{degrees}C were completed. The results of mechanical and erosion tests are used to correlate mechanical properties of selected wrought alloys such as tensile toughness, ductility, strain hardening coefficient and yield strength to their erosion resistance at 400{degrees}C. Preliminary results of correlations between erosion resistance of wrought alloys at 400{degrees}C and their mechanical properties are presented in this progress report.
NSDL National Science Digital Library
In this environmental science activity (page 3 of the PDF), leaners will identify and explain the causes of erosion. They will observe the effects of erosion on the surrounding area and further explore examples of erosion online. An extension activity allows learners to make a hands-on model of soil erosion. Though this was created as a pre-visit activity for a workshop about water flow and erosion, it makes a great stand-alone activity as well!
Trends in project cost control systems
SN Nandi; BK Dutta
The salient features of a cost control approach that could make it effective in an engineering plant construction project environment have been analysed. Various project cost control approaches (pre-and post-network based ones along with PERT\\/COST) are reviewed. The trends indicate that future project cost control will be more decentralised but more closely integrated in terms of achieving total project objectives.
UMTRA Project document control system manual
Not Available
This manual defines the Project Document Control System (PDCS) operated by the US DOE Uranium Mill tailings Remedial Action (UMTRA) project Office. The purpose of the PDCS is to provide an active and continuing program for acquiring, controlling, retaining, retrieving, retiring and disposing of all UMTRA Project documents. The PDCS also provides guidance and coordination in transferring documents by various UMTRA Projection document control centers to a central location.
Open Innovation and the Erosion of the Traditional Information Systems Project's Boundaries
NASA Astrophysics Data System (ADS)
Elbanna, Amany
This paper examines the notion of open innovation and its implication on information systems management. It investigates a project of an enterprise resource planning system implementation in an international organization to unravel the resemblance with the open innovation model. The study shows that the conceptualization of ERP project as an open innovation could reveal the complex architecture of today's organization from which the ERP project cannot be isolated. It argues that the traditional boundaries around IS projects are dissolving and the relationship between what used to be outside and what used to be inside the project is increasingly blurred. The study calls for a different perspective of project management that goes beyond single and multiple project management to scan the open space of innovation and actively look for partners, competitors, and collaborators.
Influence of Gully Erosion Control on Amphibian and Reptile Communities within Riparian Zones of Channelized Streams
Technology Transfer Automated Retrieval System (TEKTRAN)
Riparian zones of streams in northwestern Mississippi have been impacted by agriculture, channelization, channel incision, and gully erosion. Riparian gully formation has resulted in the fragmentation of remnant riparian zones within agricultural watersheds. One widely used conservation practice for...
Holocene Fire, Climate and Erosion in the Jemez Mountains, New Mexico: Natural and Anthropogenic Controls
NASA Astrophysics Data System (ADS)
Meyer, G. A.; Fitch, E. P.
Ponderosa pine and mixed-conifer forests in the Jemez Mountains have been ravaged by extensive severe fires in the last two decades, which burned almost 1000 km2, roughly 30% of this middle-elevation range. Tree-ring fire history reconstructions indicate that a low-severity fire regime characterized the ca. 400 years before Euroamerican settlement, and that fuel buildup from fire suppression and land-use impacts contributed to increased fire severity in recent years. In order to better understand natural variability, climatic influences, and erosional effects of wildfire activity since ~5000 cal yr BP, we identified and 14C-dated fire-related alluvial deposits in the 2002 Lakes Fire area in the southwestern Jemez Mountains. These deposits indicate that most late Holocene fire-related erosional events were relatively minor, consistent with the low-severity burns that dominate the tree-ring record, but larger debris flows also occurred, suggesting at least small areas of high-severity fire. Although changes in postfire sedimentation are not so clearly related to millennial-scale Holocene climatic changes as in the Northern Rocky Mountains, peaks in fire-event probability correspond with severe regional multidecadal droughts ca. 1800 and 375 cal yr BP. Local microclimatic controls on vegetation, soils, and post-fire sedimentation are also evident. Relatively dense mixed-conifer stands including Douglas-fir typify moister north-facing basins, where soils are apparently thicker and more permeable than on southerly aspects. Alluvial fans of these basins are dominated by fire-related deposits (77% of measured stratigraphic thickness), thus we interpret that little erosion occurs in the absence of wildfires. Holocene fire-related events from north slopes are also of somewhat lower frequency, and possibly of higher severity. In contrast, in ponderosa pine-dominated south-facing basins, fire-related deposits make up only 39% of measured fan deposits. On drier south aspects, thin soils, large areas of steep exposed bedrock, and sparser vegetation allow greater runoff and sediment in the absence of fire, making for a lesser relative importance of fire in erosion. The lack of exposed and dated deposits older than 5000 cal yr BP, even where fan feeder channels were incised to bedrock in debris-flow and flood events after the 2002 Lakes Fire, indicates that most stored alluvium was scoured from these channels in the middle Holocene, possibly from more severe fires and postfire erosion. It also suggests that erosional response after the Lakes Fire was at least locally greater than at any time in the last 5000 yr, possibly from the combined influence of fire suppression and recent warming and severe drought. However, expansion of this small study area would allow a clearer view of fire-climate-erosional linkages in the Jemez Mountains, and the degree to which modern climatic warming and anthropogenic impacts have heightened severe fire activity.
Straw Blankets Sewn With Recycled Plastic Threads for Erosion and Urban Sediments Control
Terezinha Cßssia de Brito GalvŃo; Aloisio Rodrigues Pereira; Arnaldo Teixeira Coelho; Paula Rodrigues Pereira; Joaquim Fernandes Teixeira Coelho
Soil erosion, transport and deposition of sediments represent invisible threats that along time can affect negatively the\\u000a existing infrastructure of roads and dams, and the quality of air and water resources. In the last decades, a great number\\u000a of researches were devoted to study erosion and sediments transportation processes. However, they addressed mostly areas of\\u000a agriculture, water impoundments for dams,
WEPPCAT: An Online tool for assessing and managing the potential impacts of climate change on sediment loading to streams using the Water Erosion Prediction Project (WEPP) Model
WEPPCAT is an on-line tool that provides a flexible capability for creating user-determined climate change scenarios for assessing the potential impacts of climate change on sediment loading to streams using the USDA?s Water Erosion Prediction Project (WEPP) Model. In combination...
Assessment of gas turbine erosion. Volume 1. Assessment of available erosion data
Boericke, R.R.; Grey, D.A; Spriggs, R.R.; Hantman, R.G.; Kuo, J.T.; Tabakoff, W.; Hamed, A.
This project was designed to address the question of gas turbine tolerance in the particle laden environment of pressurized fluidized bed (PFB) combustion gas. The project objectives were to investigate previous gas turbine erosion tests, to design a turbine erosion test facility and to plan a long range test program for commercializing this gas turbine application. This first volume of a two volume report reviews experience in the US and Australia on gas turbine erosion in a pressurized fluidized bed-type environment. From this literature search it was concluded that successful operation of PFB powered turbines is obtainable. However, there is insufficient data available at this time to permit a prediction of turbine life to be made in this type of erosive/corrosive environment. Therefore, three types of erosion/corrosion experiments must be performed to completely establish turbine capabilities in particulate laden environments. The first should consist of well controlled experiments where the effects of blade shape, blade size, particle size, gas velocity, and other controllable parameters are established over a wide range. The second set of experiments should consist of combined erosion/corrosion rig experiments in which candidate materials will be screened for relative performance under a simulated PFBC environment. The final and critical experiment should be the testing of the proposed gas turbine under actual operating conditions for extended periods. (LCL)
Barrier erosion control test plan: Gravel mulch, vegetation, and soil water interactions
Waugh, W.J.; Link, S.O. (Pacific Northwest Lab., Richland, WA (USA))
Soil erosion could reduce the water storage capacity of barriers that have been proposed for the disposal of near-surface waste at the US Department of Energy's Hanford Site. Gravel mixed into the top soil surface may create a self-healing veneer that greatly retards soil loss. However, gravel admixtures may also enhance infiltration of rainwater, suppress plant growth and water extraction, and lead to the leaching of underlying waste. This report describes plans for two experiments that were designed to test hypotheses concerning the interactive effects of surface gravel admixtures, revegetation, and enhanced precipitation on soil water balance and plant abundance. The first experiment is a factorial field plot set up on the site selected as a soil borrow area for the eventual construction of barriers. The treatments, arranged in a a split-split-plot design structure, include two densities of gravel admix, a mixture of native and introduced grasses, and irrigation to simulate a wetter climate. Changes in soil water storage and plant cover are monitored with neutron moisture probes and point intercept sampling, respectively. The second experiment consists of an array of 80 lysimeters containing several different barrier prototypes. Surface treatments are similar to the field-plot experiment. Drainage is collected from a valve at the base of each lysimeter tube, and evapotranspiration is estimated by subtraction. The lysimeters are also designed to be coupled to a whole-plant gas exchange system that will be used to conduct controlled experiments on evapotranspiration for modeling purposes. 56 refs., 6 figs., 8 tabs.
[Anti-erosion effect of hedgerows in hillside croplands of Danjiangkou based on the evaluation with water erosion prediction project (WEPP) model].
Xiong, Qin-xue; Liu, Zhang-yong; Yao, Gui-zhi; Li, Ben-zhou
Based on the data of field experiments on the hillside croplands of Danjiangkou, Hubei Province of China, the input files of crop characters, management measures, slope gradient and length, and soil properties for running WEPP model (Hillslope version) were established. Combining with the local weather data, a simulation study with the model was made on the runoff and soil loss of the croplands protected by four kinds of hedgerows (Amorpha fruticosa, Lonicera japonica, Hemerocallis fulva, and Poa sphondylodes) in Danjiangkou area. The resulted showed that WEPP model could accurately simulate the anti-erosion effect of hedgerows in hillside farmlands in the study area. Using this model not only reduced test number, but also saved time and effort, being able to provide scientific basis for the popularization and application of hedgerows. Among the four hedgerows, Amorpha fruticosa had the best anti-erosion effect. According to the simulation, the optimal planting density of A. fruticosa hedgerows in the farmlands was 1 m x 15 m at slope gradient 5 degrees, 1 m x 10 m at slope gradient 15 degrees, and 1 m x 3 m at slope gradient 25 degrees. PMID:21265164
NASA Technical Reports Server (NTRS)
2003-01-01[figure removed for brevity, see original site] The impact crater in this THEMIS image is a model illustration to the effects of erosion on Mars. The degraded crater rim and several landslides observed in crater walls is evidence to the mass wasting of materials. Layering in crater walls also suggests the presence of materials that erode at varying rates.Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.Image information: VIS instrument. Latitude 31.6, Longitude 44.3 East (315.7 West). 19 meter/pixel resolution.
Effective and low cost erosion control of inactive coal storage piles
D. E. Simmons; G. M. Degenhardt; R. W. Jones
Erosion of coal stockpiles by wind and rain cost utilities thousands of dollars each year in lost fuel, coal pile maintenance and environmental equipment. The main problem at Nelson Unit 6 was loss due to frequent and heavy rains. Average yearly rainfall in that part of Louisiana is 56''. There is a definite ''rainy season'' in the winter months and
Evaluating Material Properties to Optimize Wood Strands for Wind Erosion Control
Technology Transfer Automated Retrieval System (TEKTRAN)
Wind erosion is a widespread problem in much of the western United States due to arid conditions and persistent winds. Fugitive dust from eroding land poses a risk to both environmental quality and human health. Since the advent of the Clean Air Act in 1971, ambient air quality standards have been ...
Use of cover crops in short rotation hardwood plantations to control erosion
R. K. Malik; T. H. Green; G. F. Brown; D. Mays
This study was designed to test whether the cultivation of cover crops between tree rows in short-rotation woody crop (SRWC) plantations could reduce erosion. Sweetgum (Liquidambar styraciflua L.) seedlings were planted as the SRWC at a 1.5ū3Ām spacing. Four cover crops, annual ryegrass (Lolium multiflorum L. a winter annual grass); tall fescue (Festuca arundinacea L. a cool-season perennial grass); crimson
An investigation of bergmounds as analogs to erosion control factors on protective barriers
Chamness, M.A.
Included in several of the final disposal strategies proposed in the Interim Hanford Waste Management Plan (DOE-RL 1986a) is design of a protective barrier to isolate the underlying waste sites from the environment. The conceptual protective barrier design requires a fine-grained sediment to retain precipitation near the top of the barrier where evapotranspiration can recycle the moisture back into the atmosphere. The design incorporates gravel into the topsoil as one way to reduce its erosion. Information is needed to determine the optimal ratio of gravel to topsoil needed to reduce erosion without significantly reducing evapotranspiration, and its effect on erosion. Bergmounds are mounds with a gravelly surface that were formed about 13,000 years ago and represent natural analogs to the topsoil portion of the protective barrier. The primary goal of this study was to identify characteristics of bergmounds and the effects of these characteristics, especially the gravelly surface, on the amount and rate of erosion. A secondary goal was to apply a technique normally used to estimate vegetation cover to measure percent gravel cover, and to compare this technique with particle size distribution based on weight percent. Four bergmounds were investigated for this study, two in a windy site and two in a more sheltered site. Each bergmound was sampled in eight locations. Two methods were used to estimate the amount of surface gravel: the ocular point-intercept method which estimates the percent gravel cover, and sieved samples of the surface sediments which measure the percent gravel by weight. Holes were dug at each bergmound`s eight sampling sites to examine and sample the subsurface sediments.
NASA Technical Reports Server (NTRS)
[figure removed for brevity, see original site]The ejecta surrounding the crater (off image to the left) in this image has undergone significant erosion by the wind. The wind has stripped the surface features from the ejecta and has started to winnow away the ejecta blanket. Near the margin of the ejecta the wind is eroding along a radial pattern -- taking advantage of radial emplacement. Note the steep margin of the ejecta blanket. Most, if not all, of the fine ejecta material has been removed and the wind in now working on the more massive continuous ejecta blanket. Image information: VIS instrument. Latitude 12.5, Longitude 197.4 East (162.6 West). 37 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.
Chronic erosion in Wissant Bay coast, northern France - Causes and trials of management projects
NASA Astrophysics Data System (ADS)
Sedrati, M.; Anthony, E. J.
Cape Gris Nez to the southwest and Cape Blanc Nez to the northeast limit's Wissant Bay. This extreme northern coast of France, facing the Dover Strait, is one of the most rapidly eroding sector of coast in France. Shoreline retreat has exceeded 250 m in the last fifty years in the central and western parts of the bay, while the eastern sector of the bay is now a zone of accretion, after being a sand-starved zone in the past, when the western sector was either stable or in accretion. The reasons for these changes are still not clear. They seem to involve interactions between a nearshore sand bank and the activity of current gyres related to the projecting headland of Cape Gris Nez, beach rotation processes and human activities, notably past aggregate extraction from the nearshore sand bank which acted hitherto as both a dissipater of incident storm wave energy and as a coastal sand source. The aim of this paper to contribute to the understanding of these long-term changes and investigate the mechanisms of this mildly embayed coast evolution. To this end, 10-years of topographic profile data throughout the bay were analysed and confronted with offshore wave data. This analysis complements a previous analytical effort that determined gross rates of annual shoreline retreat by time slices of several decades from the careful interpretation of long series of ortho-rectified aerial photographs. The overall data suggest chronic sand bleeding from the western sector of the beach and longshore transport to the east, within a framework of what appears to be an ongoing beach rotation process within a dominant longshore sediment transport cell between the headland of Cape Gris Nez and the bold chalk cliffs of Cape Blanc Nez. Retreat of the beach-dune barrier in the western sector of Wissant Bay poses a threat in the coming years as there is a likelihood of storm breaching of the narrow dune barrier. Face to this critical situation, a proper management strategy involving a good understanding and an integrated view of beach and coastal dynamics, as well as defence strategies covering not only the beaches but also the dunes and the nearshore zone must be applied. This can only be effectively done within the framework of the immediate implementation of Integrated Coastal Zone Management.
Micro-Management of Lighting Controls Projects
Clark, W. H.
A common lighting project is to evaluate a block of rooms for savings and payback from the use of photocells or occupancy sensors. The designer counts the fixtures to be controlled, calculates the watts used and then the expected savings...
Technology Transfer Automated Retrieval System (TEKTRAN)
Wind erosion refers to the detachment, transport and deposition of sediment by wind. It is a dynamic, physical process where loose, dry, bare soils are transported by strong winds. Wind erosion is a soil degrading process that affects over 500 million ha of land worldwide and creates between 500 an...
Technology Transfer Automated Retrieval System (TEKTRAN)
Irrigation is essential for global food production. However, irrigation erosion can limit the ability of irrigation systems to reliably produce food and fiber in the future. The factors affecting soil erosion from irrigation are the same as rainfallŚwater detaches and transports sediment. However, t...
Erosion control on a steeply sloped pipeline right-of-way in southwestern Pennsylvania: Final report, June 1984--April 1988
Zellmer, S.D.; Taylor, J.D.
Soil erosion by precipitation on steeply sloped pipeline rights-of-way (ROWs) in the period between ROW rehabilitation and development of a dense, self-sustaining vegetative ground cover can cause locally severe soil losses, elevated sediments loads in receiving streams, and increase difficulty and cost of ROW maintenance. This field study, funded by the Gas Research Institute and conducted by Argonne National Laboratory, compared the environmental effectiveness of nine treatments (six methods and three controls) on a 23% ROW slope in southwestern Pennsylvania. Replicated plots were established, immediately after ROW cleanup, over the pipeline and on the working side of the ROW. The six prevegetation methods represented a wide range of material and installation costs. Precipitation, runoff volumes, and sediment yields were measured at each of 51 plots for 45 precipitation events during the 18-month study. Vegetation data were collected by the point-intercept method four times during the study to determine the amount of plant cover and species composition. Differences in sediment yield were observed among methods and between ROW locations, but plant cover development was not influenced by method or location. The relationship between environmental and cost data indicated that, of the six erosion control methods tested, straw mulch applied at the rate of 3.35 metric tons per hectare (1.5 tons/acre) was the most effective. 38 refs., 6 figs., 14 tabs.
Cate, H. J. Ten Bruggen
Five hundred and fifty-five acid workers were examined between March 1962 and October 1964. One hundred and seventy-six (31Ę7%) were affected by industrial dental erosion at the first examinations. In 33 cases (6Ę0%) the dentine was affected. During the period of the survey, 66 (20Ę4%) of 324 workers examined more than once showed evidence that erosion was progressing. The prevalence and incidence of erosion were highest among battery formation workers, lower among picklers, and least among other processes covered by the survey. The age of workers did not appear to influence their susceptibility to erosion. The habit of working with the lips slightly parted had little effect. Erosion superimposed upon attrition predisposed to more severe loss of tooth structure than either operating alone. Little inconvenience or functional disability was suffered by acid workers due to erosion. Twenty-seven (23Ę7%) of 114 erosions were considered to be disfiguring. Regular dental treatment was sought less by acid workers than by controls, and the oral hygiene of the latter was superior. There was no evidence to show any difference between caries experience among acid workers and controls. Calculus and periodontal disease were more prevalent among acid workers than among controls, but it was not possible to attribute this to the working environment. Black staining in iron picklers was considered to be due to the working environment. The use of closed acid containers or lip extraction on open acid vats prevented significant atmospheric contamination and diminished the prevalence of erosion. The use of wall fans and detergent foaming agents was helpful. Images PMID:5723349
Assessment of Soil Moisture and Fixatives Performance in Controlling Wind Erosion of Contaminated Soil at the Hanford Site
Lagos, L.E.; Gudavalli, R.K. [Applied Research Center, Florida International Univ., Miami, FL (United States)
During the remediation of burial grounds at the US Department of Energy's (DOE's) Hanford Site in Washington State, the dispersion of contaminated soil particles and dust is an issue that is faced by site workers on a daily basis. This contamination issue is even more of a concern when one takes into account the semi-arid characteristics of the region where the site is located. To mitigate this problem, workers at the site use a variety of engineered methods to minimize the dispersion of contaminated soil and dust particles. Once such methods is the use of water and/or suppression agents (fixatives) that stabilizes the soil prior to soil excavation, segregation, and removal activities. A primary contributor to the dispersion of contaminated soil and dust is wind soil erosion. The erosion process occurs when the wind speed exceeds a certain threshold value (threshold shear velocity), which depends on a number of factors including wind force loading, particle size, surface soil moisture, and the geometry of the soil. Thus under these circumstances the mobility of contaminated soil and generation and dispersion of particulate matter are significantly influenced by these parameters. Wind tunnel experiments were conducted at the Florida International University's Applied Research Center (FIU-ARC) to evaluate the effectiveness of three commercially available fixatives in controlling the mobility of soil particles on soil mounds when exposed to varying wind forces. The fixatives tested included: (1) a calcium chloride solution; (2) a petroleum hydrocarbon emulsion; and 3) a synthetic organic. As an initial step, approximately 500 lbs of uncontaminated soil was obtained from the Hanford Reservation in Washington State. Soil samples were placed in an open-loop, low speed wind tunnel and exposed to wind forces ranging from 10 to 30 miles per hour (mph). Wind erosion controlling capabilities of commercially available fixatives and soil moisture were tested at a laboratory scale. Soil samples with varying moisture (W/W %) content and soil samples treated with fixatives, selected from a wide range of commercially available products, were exposed to a wind speeds ranging from 10 - 30 miles per hour (MPH). During these experiments, amount of soil displaced due to the wind forces, the amount of airborne particulates generated, and the moisture loss were measured to better understand the performance of selected fixatives and soil moisture. Results obtained during the study showed that there is a significant reduction in wind erosion and airborne particles generation by increasing the soil moisture for the velocities tested. Similar trend was observed when the soil samples treated with fixatives were exposed to the same range of velocities (10 - 30 MPH). (authors)
Analysis/control of in-bed tube erosion phenomena in the fluidized bed combustion system. Final technical report
Lee, Seong W.
Research is presented on erosion and corrosion of fluidized bed combustor component materials. The characteristics of erosion of in-bed tubes was investigated. Anti-corrosion measures were also evaluated.
Contour Ripping and Composted Dairy Manure for Erosion Control on Fort Hood Military Installation, TexasĀ
Prcin, Lisa J.
Members, William E. Fox Charles T. Hallmark Dennis W. Hoffman Head of Department, Steven G. Whisenant May 2009 Major Subject: Rangeland Ecology and Management iii iii ABSTRACT Contour Ripping and Composted Dairy Manure for Erosion... the efforts of many. I must thank Dr. Dennis Hoffman; I will be eternally grateful to you for allowing me the opportunity to gain experience in this field and for taking a chance on me when I knew next to nothing about rangeland re-vegetation and even less...
Knox, A.; Paller, M.; Dixon, K.
The final project report for SEED SERDP ER - 2134 describes the development of permeable active amendment concrete (PAAC), which was evaluated through four tasks: 1) development of PAAC; 2) assessment of PAAC for contaminant removal; 3) evaluation of promising PAAC formulations for potential environmental impacts; and 4) assessment of the hydraulic, physical, and structural properties of PAAC. Conventional permeable concrete (often referred to as pervious concrete) is concrete with high porosity as a result of an extensive and interconnected void content. It is made from carefully controlled amounts of water and cementitious materials used to create a paste that forms a coating around aggregate particles. The mixture has a substantial void content (e.g., 15% - 25%) that results in a highly permeable structure that drains quickly. In PAAC, the aggregate material is partly replaced by chemically-active amendments that precipitate or adsorb contaminants in water that flows through the concrete interstices. PAAC combines the relatively high structural strength, ample void space, and water permeability of pervious concrete with the contaminant sequestration ability of chemically-active amendments to produce a new material with superior durability and ability to control contaminant mobility. The high surface area provided by the concrete interstices in PAAC provides significant opportunity for contaminants to react with the amendments incorporated into the concrete matrix. PAAC has the potential to immobilize a large variety of organic and inorganic contaminants by incorporating different active sequestering agents including phosphate materials (rock phosphate), organoclays, zeolite, and lime individually or in combinations.
Interactive control of minerals, wildfire, and erosion on soil carbon stabilization in conifer ecosystems of the western U.S.
NASA Astrophysics Data System (ADS)
Rasmussen, C.
Answering the question of what controls the fate and stabilization of organic carbon in forest soils is central to understanding the role of western US ecosystems in mitigating climate change, optimizing forest management, and quantifying local and regional terrestrial carbon budgets. Over half of forest soil C is stored belowground, stabilized by a number of separate, but interacting physical, chemical and biological mechanisms. Here we synthesize data from a series of field and laboratory studies focused on identifying mineral, physical, and landscape position controls on belowground C stabilization mechanisms in western U.S. conifer ecosystems. Results from these studies demonstrate an important for role for short-range-order Fe- and Al-oxyhydroxides and Al-humus complexes in C stabilization, and that the soil mineral assemblage moderates C cycling via control on partitioning of C into physical fractions ("free", "occluded", "mineral") with varying MRT and chemistry. Measures of occluded fraction chemical composition by 13C-NMR indicate this fraction is 2-5 times more enriched in pyrogenic C than the bulk soil and that this fraction is on the order of ~25 to 65% charred materials. Radiocarbon analyses of a large set of conifer soil samples from California and Arizona further indicate the occluded fraction is generally older than either the free light or mineral fraction. In particular, soil C in convergent, water and sediment gathering portions of the landscape are enriched in long MRT charred materials. These results indicate an important role for the interaction of soil mineral assemblage, wildfire, and erosion in controlling belowground C storage and stabilization in western conifer forests. Drought and wildfire are expected to increase with climate change and thus may exert significant control on belowground C storage directly through biochemical and physical changes in aboveground biomass, production of charred materials, and indirectly via post-fire physical erosion and redistribution of C-rich sediment across the landscape.
Effects of erosion control structures along a portion of the northern Chesapeake Bay shoreline
Zabawa, C.F.; Kerhin, R.T.; Bayley, S.
A 6.500-meter reach of western Chesapeake Bay shoreline (lower Mayo Peninsula) lost about 1.1??106 cubic meters of sediment (equivalent to 170 cubic meters lost per meter of shoreline) between 1846 and 1932, when the first aerial photographs show the shoreline already substantially protected by a system of groins and intermittent bulkheading. These structures have eliminated the fastland as a source of erodable material, and have starved the supply of sand for littoral drift, thus limiting the extent of the beaches to the remaining groin fields. Volumes of sediment involved in these impacts are small in the overall sediment budget. Bulkheads produce no deficit in the budget since scouring of the beaches on their seaward sides makes up for the decreased erosion of protected fastland. Groins trap little of the potential littoral drift (computed to be about 104 cubic meters per meter of shoreline per year). The sand supply in the remaining beaches is nearly equivalent to the annual loss of sediment from the entire shoreline system due to the long-term rate of erosion of the shoreline and nearshore between 1846 and 1932. ?? 1981 Springer-Verlag New York Inc.
Couplages Tectonique -Erosion Berger, 2008
Demouchy, Sylvie
Couplages Tectonique -Erosion Berger, 2008 #12;Couplages Tectonique -Erosion #12;Couplages Tectonique -Erosion #12;Couplages Tectonique -Erosion #12;Couplages Tectonique -Erosion #12;Couplages Tectonique -Erosion #12;Couplages Tectonique -Erosion #12;Couplages Tectonique -Erosion #12;Couplages
Links between erosion, runoff variability and seismicity in
Lin, Andrew Tien-Shun
.............................................................. Links between erosion, runoff ............................................................................................................................................................................. The erosion of mountain belts controls their topographic and structural evolution1Ł3 and is the main source of sediment delivered to the oceans4 . Mountain erosion rates have been estimated from current relief
The spatiotemporal control of erosion and molecular release from micropatterned poly(ethylene glycol)-based hydrogel.
Yonet-Tanyeri, Nihan; Rich, Max H; Lee, Minkyung; Lai, Mei-Hsiu; Jeong, Jae Hyun; DeVolder, Ross J; Kong, Hyunjoon
Hydrogels have been extensively studied as a carrier of various hydrophilic molecular compounds and cells for local delivery and subsequent controlled release. One of key design parameters in the hydrogel assembly is an ability to control spatiotemporal gel degradation, in order to tailor release rates of multiple drugs and also regulate phenotypic activities of co-cultured cells. To achieve this goal, this study presents a simple but innovative implantable, microfabricated hydrogel patch that undergoes micropatterned surface erosion at controlled rates and subsequently discharges two molecular compounds of interests at desired rates. This device was prepared by first fabricating a non-degradable poly(ethylene glycol) dimethacrylate (PEGDMA) hydrogel patch containing micro-pockets of controlled spacing and subsequently filling micro-pockets with a hydrogel of poly(ethylene imine) (PEI) and PEG diacrylate (PEGDA) that was tailored to degrade at controlled rates. Separate incorporation of vascular endothelial growth factor (VEGF)121 and VEGF165, known to orchestrate vascular development, into the PEI-PEGDA gel and PEGDMA hydrogel resulted in enhanced neovascularization at the implantation sites due to bimodal, sequential release of two VEGF isoforms. We believe that the hydrogel patch fabricated in this study will be highly useful to better understand a broad array of complex biological processes and also improve the efficacy of molecular cargos in varied applications. PMID:23886733
Tank Waste Remediation System Projects Document Control Plan
Slater, G.D.; Halverson, T.G.
The purpose of this Tank Waste Remediation System Projects Document Control Plan is to provide requirements and responsibilities for document control for the Hanford Waste Vitrification Plant (HWVP) Project and the Initial Pretreatment Module (IPM) Project.
Measurement of the fluorescence of crop residues: A tool for controlling soil erosion
NASA Technical Reports Server (NTRS)
Daughtry, C. S. T.; Mcmurtrey, J. E., III; Chappelle, E. W.; Hunter, W. J.
Management of crop residues, the portion of a crop left in the field after harvest, is an important conservation practice for minimizing soil erosion and for improving water quality. Quantification of crop residue cover is required to evaluate the effectiveness of conservation tillage practices. Methods are needed to quantify residue cover that are rapid, accurate, and objective. The fluorescence of crop residue was found to be a broadband phenomenon with emission maxima at 420 to 495 nm for excitations of 350 to 420 nm. Soils had low intensity broadband emissions over the 400 to 690 nm region for excitations of 300 to 600 nm. The range of relative fluorescence intensities for the crop residues was much greater than the fluorescence observed of the soils. As the crop residues decompose their blue fluorescence values approach the fluorescence of the soil. Fluorescence techniques are concluded to be less ambiguous and better suited for discriminating crop residues and soils than reflectance methods. If properly implemented, fluorescence techniques can be used to quantify, not only crop residue cover, but also photosynthetic efficiency in the field.
Modeling erosion and sediment control practices in RUSLE 2.0: A management approach for natural gas well sites in Denton County, TX, USA
Technology Transfer Automated Retrieval System (TEKTRAN)
Sediment yields from natural gas well sites can be substantial and warrant consideration of appropriate erosion and sediment control Best Management Practices(BMPs). Version 2 of the Revised Universal Soil Loss Equation (RUSLE 2.0) was used to predict sediment yields and evaluate the efficiency of ...
Rainfall Energy Variability across Pennsylvania: Impacts on Construction Site Erosion Control Practices Aigul Allison and Shirley E. Clark, Ph.D., P.E., D WRE
Clark, Shirley E.
Rainfall Energy Variability across Pennsylvania: Impacts on Construction Site Erosion Control Equation (USLE), such as RUSLE or RUSLE 2, where: A = RK(LS)CP Where R = rainfall energy, K = soil coefficient. If data is available, the USLE rainfall energy (R) can be derived from the estimated rainfall
Recurrent erosion of the cornea
N. Brown; A. Bron
Altogether, 80 patients aged between 24 and 73 years with recurrent erosion of the cornea have been studied and compared with a control group of 200. The patients' erosions were divisible into macroform and microform types. The macroform occurred in 10%, the microform in 56%, and both types in the same patients in 31%. The macroform was more commonly related
77 FR 47063 - Notice of Availability of Draft Revisions; Upland Erosion Control, Revegetation, and Maintenance...
Federal Register 2010, 2011, 2012, 2013, 2014
...Revegetation, and Maintenance Plan; Wetland and Waterbody Construction and Mitigation...Revegetation, and Maintenance Plan (Plan) and Wetland and Waterbody Construction and Mitigation...duration of project-related disturbance on wetlands and waterbodies. Attached to this...
Technology Transfer Automated Retrieval System (TEKTRAN)
Degradation of aquatic habitats, especially warmwater streams in agricultural landscapes is a pervasive problem. Although projects to rehabilitate stream ecosystems have become quite numerous, reports of effectiveness based on monitoring data are rare. Some workers suggest that rehabilitation effort...
NSDL National Science Digital Library
David Tenenbaum
This Why Files article considers beach erosion. Topics covered are: the nature and extent of beach losses, the role of beaches in protecting coasts, some measures -good and bad- to prevent coastal erosion, predicted effects of global warming and sea-level changes on beaches and the impact of melting ice sheets on global ocean volume. Some glaciologists using new calculations, think that instead of possibly collapsing in 100 years, as was considered possible 10 years ago, that the West Antarctic Ice Sheet is more likely to collapse in perhaps 5,000 years at the soonest. Five scientists were interviewed for this article.
Do erosion rates control the long-term carbon isotope mass balance?
NASA Astrophysics Data System (ADS)
Shields-Zhou, G. A.
The long-term marine carbon isotope record responds to changes in the proportional burial rates of organic carbon relative to carbonate carbon on a global scale. For this reason, high ?13C values in marine carbonate rocks are normally interpreted to reflect faster rates of organic burial and increased atmospheric oxygenation. Geochemical redox tracers fail to support this paradigm for sustained deviations from the long-term ?13C mean, indicating perhaps that proportionally high organic burial may be associated with lower overall flux rates. Here I propose that ~107-108 year trends in average ?13C, as with seawater 87Sr/86Sr, are driven by changes in the balance between volcanism and denudation (~uplift). In other words, high proportional organic burial may be related to increases in the net CO2 flux (= organic carbon burial + Ca-Mg silicate weathering) relative to the carbonate weathering flux. According to this model, high baseline ?13C values will be associated with periods of heightened volcanic activity and/or diminished tectonic uplift. Conversely, lower baseline ?13C values can be related to times when the global carbon cycle was dominated by carbonate and oxidative weathering due to high rates of physical erosion. Shorter 105-106 year positive ?13C excursions have also been interpreted as the 'smoking gun' to extreme oxygenation events. However, large increases in organic burial are difficult to sustain under steady-state conditions without very high volcanic fluxes, indicating that some of these excursions might be better explained by transient changes to the isotopic composition of carbon sources and sinks.
Using soil erosion models for global change studies
J. Williams; K. King; M. Nearing
Future changes in climate and atmospheric carbon dioxide concentration will change the hydrologic cycle, affecting important soil-plant-water interactions, which in turn affect soil erosion rates. This report describes major soil erosion models which include Environmental Policy Integrated Climate (EPIC); Water Erosion Prediction Project (WEPP); Wind Erosion Prediction System (WEPS); and the Climate generator Model (CLIGEN).
Using Thermochronology to Understand Orogenic Erosion
Jellinek, Mark
Using Thermochronology to Understand Orogenic Erosion Peter W. Reiners and Mark T. Brandon, geomorphology, tectonics Abstract Erosion of orogenic mountain ranges exhumes deeply buried rocks and controls weathering, climate, and sediment production and transport at a variety of scales. Erosion also affects
Field studies of beach cones as coastal erosion control/reversal devices for areas with significant oil and gas activities
Not Available
A field demonstration/study of a novel shoreline erosion protection device called beach cones is planned. These patented, fiberglass- reinforced concreted devices are to be deployed in a number of geometric patterns at seven location in the Bastian Bay area of Western Plaquemines Parish. The purpose of the work described in this report was to evaluate the proposed study's impact on living and non-living shellfish resources within each of the project's seven separate Study Areas. Major accomplishments for this reporting period were as follows: aerial photographs of the experimental sites were taken; all permit applications were filed; information was submitted for the Environmental Report; several reconnaissance trips to the experimental sites were made; meetings were held among all participating organizations to further plan the research; permit was obtained from the US Army Corps of Engineers; test sites were surveyed by the Xavier University contingent; survey data were taken at all sites; the Oyster Assessment was completed; permit was obtained from the State of Louisiana Department of Natural Resources; and initial survey data were finalized at all sites.
NASA Astrophysics Data System (ADS)
Ristroph, Leif; Moore, M. N. J.; Childress, Stephen; Shelley, Michael; Zhang, Jun
Erosion by flowing fluids carves the striking landscapes imprinted on the Earth and on the surfaces of our neighboring worlds. In these processes, solid boundaries both influence and are shaped by the surrounding fluid, but the emergence of morphology as a result of this interaction is not well understood. We study the coevolution of shape and flow in the context of clay bodies immersed in fast flowing water. Although commonly viewed as a smoothing process, we discover that erosion sculpts surprisingly sharp points and corners that persist as the body shrinks. These features result from a natural tendency to form surfaces that erode uniformly, and we argue that this principle may also apply to the more complex scenarios that occur in nature.
If states in the Corn Belt adopt varying soil loss limits as a part of a nonpoint source of water pollution control program will there be adverse economic consequences. If so, what types of impacts would be felt and would they be severe. The objective of this analysis was focused...
Environmental Impact Statement Truckee Meadows Flood Control Project
US Army Corps of Engineers
DRAFT Environmental Impact Statement for the Truckee Meadows Flood Control Project Nevada General 2013 #12;#12;DRAFT Environmental Impact Statement for the Truckee Meadows Flood Control Project Nevada
Project W-058 monitor and control system logic
This supporting document contains the printout of the control logic for the Project W-058 Monitor and Control System, as developed by Programmable Control Services, Inc. The logic is arranged in five appendices, one for each programmable logic controller console.
Construction Project Control in Virtual Reality: A Case Study
Guo-Cheng Li; Lie-Yun Ding; Jing-Tao Wang
The construction process is a very complex undertaking. Achieving an effective control for the construction project is very difficult. A Virtual Construction Project Control System (VCPCS) is presented in this study and applied to a practical construction project in Shanghai, China, say, Chia-Tai Mall. VCPCS is the first Virtual Reality (VR) system for a large-scale real construction project in China.
A Statistical Project Control Tool for Engineering Managers
NASA Technical Reports Server (NTRS)
Bauch, Garland T.
This slide presentation reviews the use of a Statistical Project Control Tool (SPCT) for managing engineering projects. A literature review pointed to a definition of project success, (i.e., A project is successful when the cost, schedule, technical performance, and quality satisfy the customer.) The literature review also pointed to project success factors, and traditional project control tools, and performance measures that are detailed in the report. The essential problem is that with resources becoming more limited, and an increasing number or projects, project failure is increasing, there is a limitation of existing methods and systematic methods are required. The objective of the work is to provide a new statistical project control tool for project managers. Graphs using the SPCT method plotting results of 3 successful projects and 3 failed projects are reviewed, with success and failure being defined by the owner.
Application of video-cameras for quality control and sampling optimisation of hydrological and erosion measurements in a catchment
NASA Astrophysics Data System (ADS)
Lora-Millßn, Julio S.; Taguas, Encarnacion V.; Gomez, Jose A.; Perez, Rafael
Long term soil erosion studies imply substantial efforts, particularly when there is the need to maintain continuous measurements. There are high costs associated to maintenance of field equipment keeping and quality control of data collection. Energy supply and/or electronic failures, vandalism and burglary are common causes of gaps in datasets, reducing their reach in many cases. In this work, a system of three video-cameras, a recorder and a transmission modem (3G technology) has been set up in a gauging station where rainfall, runoff flow and sediment concentration are monitored. The gauging station is located in the outlet of an olive orchard catchment of 6.4 ha. Rainfall is measured with one automatic raingauge that records intensity at one minute intervals. The discharge is measured by a flume of critical flow depth, where the water is recorded by an ultrasonic sensor. When the water level rises to a predetermined level, the automatic sampler turns on and fills a bottle at different intervals according to a program depending on the antecedent precipitation. A data logger controls the instruments' functions and records the data. The purpose of the video-camera system is to improve the quality of the dataset by i) the visual analysis of the measurement conditions of flow into the flume; ii) the optimisation of the sampling programs. The cameras are positioned to record the flow at the approximation and the gorge of the flume. In order to contrast the values of ultrasonic sensor, there is a third camera recording the flow level close to a measure tape. This system is activated when the ultrasonic sensor detects a height threshold, equivalent to an electric intensity level. Thus, only when there is enough flow, video-cameras record the event. This simplifies post-processing and reduces the cost of download of recordings. The preliminary contrast analysis will be presented as well as the main improvements in the sample program.
Effect of erosion-control structures on sediment and nutrient transport, Edgewood Creek drainage, Lake Tahoe basin, Nevada, 1981-83
Garcia, K.T.
Three sites in the Edgewood Creek basin with a combined drainage area of about 1.2 sq mi were selected to assess the effect of erosion-control structures along Nevada State Highway 207, on sediment and nutrient transport. The flow at site one is thought to have been largely unaffected by urban development, and was completely unaffected by erosion control structures. The flow at site two was from a basin affected by urban development and erosion control structures. Site three was downstream from the confluence of streams measured at sites one and two. Most data on streamflow and water quality were collected between June 1981 and May 1983 to assess the hydrologic characteristics of the three sites. As a result of the erosion control structures, mean annual concentrations of total sediment were reduced from about 24,000 to about 410 mg/l at site two and from about 1,900 to about 190 ml/l at site three. Sediment loads were reduced from about 240 to about 10 tons/year at site two and from about 550 to about 110 tons/year at site three. At site one, in contrast, mean concentrations and loads remained low throughout the study period. At site two, sediment particle size changed from predominately coarse prior to construction, to predominately fine thereafter; at site three, it changed from about half coarse sediments to predominately fine. Mean concentration and loads of total iron also were significantly reduced after construction at sites two and three, whereas mean concentrations of nitrogen and phosphorus species did not change appreciably. (Author 's abstract)
The evolution of soft solutions for coastal erosion control: A study of the development of inflatable sand & water-filled geotextile devices
Sample, J.W.
The Dutch people are the first known to have employed sand-filled containers in erosion control. The myriad of enormous dikes surrounding Holland provide continuous protection to a nation which is sited largely below sea level. The earliest fabric material used in containment of sand for the construction of dikes and levees was a burlap type material which had severe limitations. The problem has been primarily related to the inadequacies of the fabric materials containing the sand fill. A comparable analogy exists in the aerospace industry. Incredible achievements in high speed flight which have been accomplished in the last thirty years were previously impossible due to the inadequacies of the aircraft construction materials available in the first half of the twentieth century. It is of particular interest to note that many of the {open_quotes}Space Age{close_quote} materials originally conceived through these initial alliances were later incorporated by entrepreneurs and private industry into applications and products far beyond the initial scope of their creators. The combination of high strength materials such as woven multifilament dacron thread, extrusion coated with poly vinyl chloride (PVC Plastic) has resulted in the development of heretofore unknown materials known as {open_quotes}Geotextiles{close_quotes}. Geotextile materials are high strength fabrics which have been specifically created for use in, on, under and around the earth. They incorporate exceptional strength with unique abrasion, puncture and ultraviolet resistance characteristics previously not available. The application of these space age geotextiles in the field of coastal erosion control has resulted in the development of a multitude of patented sand and water-filled erosion control devices which provide significant levels of storm protection for coastal homes and properties. This paper reviews the evolutionary development of sand and water filled systems for erosion control.
Response of stream macroinvertebrate assemblages to erosion control structures in a wastewater dominated urban stream in the southwestern U.S
S. Mark Nelson
Effects of stream erosion control structures on aquatic macroinvertebrates were studied (2000¢2009) in a wastewater dominated\\u000a drainage (Wash) in Las Vegas, Nevada. Mainstem sites with and without structures, wastewater treatment plant outfalls, a reference\\u000a site above treatment plant inputs, and tributary sites were sampled. Ordination suggested hydrology and channel characteristics\\u000a (current velocity, stream depth, and width), and water quality (conductivity)
Research progress on the effects of soil erosion on vegetation
Juying Jiao; Houyuan Zou; Yanfeng Jia; Ning Wang
The relationship between vegetation and soil erosion deserves attention due to its scientific importance and practical applications. A great deal of information is available about the mechanisms and benefits of vegetation in the control of soil erosion, but the effects of soil erosion on vegetation development and succession is poorly documented. Research shows that soil erosion is the most important
NASA Technical Reports Server (NTRS)
2006-01-014 June 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows layered, light-toned, sedimentary rocks that have been exposed by erosion in Coprates Chasma, one of the many chasms which comprise the Valles Marineris trough system on Mars. Location near: 13.1oS, 65.0oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Autumn
A method to measure clinical erosion: the effect of orange juice consumption on erosion of enamel
N. X. West; A. Maxwell; J. A. Hughes; D. M. Parker; R. G. Newcombe; M. Addy
Objective: Acidic soft drinks are frequently implicated in dental erosion, but there are limited supporting data. Research is problematic due to the insidious nature of erosion and accuracy in assessing tissue loss. The aim of this study was to develop and validate, using a negative control, a model to accurately measure erosion in situ due to a single aetiological agent
Greenidge Multi-Pollutant Control Project
Daniel Connell
The Greenidge Multi-Pollutant Control Project was conducted as part of the U.S. Department of Energy's Power Plant Improvement Initiative to demonstrate an innovative combination of air pollution control technologies that can cost-effectively reduce emissions of SO{sub 2}, NO{sub x}, Hg, acid gases (SO{sub 3}, HCl, and HF), and particulate matter from smaller coal-fired electric generating units (EGUs). There are about 400 units in the United States with capacities of 50-300 MW that currently are not equipped with selective catalytic reduction (SCR), flue gas desulfurization (FGD), or mercury control systems. Many of these units, which collectively represent more than 55 GW of installed capacity, are difficult to retrofit for deep emission reductions because of space constraints and unfavorable economies of scale, making them increasingly vulnerable to retirement or fuel switching in the face of progressively more stringent environmental regulations. The Greenidge Project sought to confirm the commercial readiness of an emissions control system that is specifically designed to meet the environmental compliance requirements of these smaller coal-fired EGUs by offering a combination of deep emission reductions, low capital costs, small space requirements, applicability to high-sulfur coals, mechanical simplicity, and operational flexibility. The multi-pollutant control system includes a NO{sub x}OUT CASCADE{reg_sign} hybrid selective non-catalytic reduction (SNCR)/in-duct SCR system for NO{sub x} control and a Turbosorp{reg_sign} circulating fluidized bed dry scrubbing system (with a new baghouse) for SO{sub 2}, SO{sub 3}, HCl, HF, and particulate matter control. Mercury removal is provided as a co-benefit of the in-duct SCR, dry scrubber, and baghouse, and by injection of activated carbon upstream of the scrubber, if required. The multi-pollutant control system was installed and tested on the 107-MW{sub e}, 1953-vintage AES Greenidge Unit 4 by a team including CONSOL Energy Inc. as prime contractor, AES Greenidge LLC as host site owner, and Babcock Power Environmental Inc. as engineering, procurement, and construction contractor. About 44% of the funding for the project was provided by the U.S. Department of Energy, through its National Energy Technology Laboratory, and the remaining 56% was provided by AES Greenidge. Project goals included reducing high-load NO{sub x} emissions to {le} 0.10 lb/mmBtu; reducing SO{sub 2}, SO{sub 3}, HCl, and HF emissions by at least 95%; and reducing Hg emissions by at least 90% while the unit fired 2-4% sulfur eastern U.S. bituminous coal and co-fired up to 10% biomass. This report details the final results from the project. The multi-pollutant control system was constructed in 2006, with a total plant cost of $349/kW and a footprint of 0.4 acre - both substantially less than would have been required to retrofit AES Greenidge Unit 4 with a conventional SCR and wet scrubber. Start-up of the multi-pollutant control system was completed in March 2007, and the performance of the system was then evaluated over an approximately 18-month period of commercial operation. Guarantee tests conducted in March-June 2007 demonstrated attainment of all of the emission reduction goals listed above. Additional tests completed throughout the performance evaluation period showed 96% SO{sub 2} removal, 98% mercury removal (with no activated carbon injection), 95% SO{sub 3} removal, and 97% HCl removal during longer-term operation. Greater than 95% SO{sub 2} removal efficiency was observed even when the unit fired high-sulfur coals containing up to 4.8 lb SO{sub 2}/mmBtu. Particulate matter emissions were reduced by more than 98% relative to the emission rate observed prior to installation of the technology. The performance of the hybrid SNCR/SCR system was affected by problems with large particle ash, ammonia slip, and nonideal combustion characteristics, and high-load NO{sub x} emissions averaged 0.14 lb/mmBtu during long-term operation. Nevertheless, the system has reduced the unit's overall NO{sub x} emiss
Large Scale Predictions of Potential Post-fire Erosion
NASA Astrophysics Data System (ADS)
Miller, M. E.; MacDonald, L. H.
High-severity wildfires are of increasing concern because of their potential for initiating flash floods and surface erosion, degrading water quality, and reducing reservoir capacity. In many areas fire suppression has increased fuel accumulations and hence the potential for high-severity wildfires. Land management agencies are undertaking programs to reduce fuel loadings and the associated risk of high-severity wildfires, but the areas needing treatment greatly exceed the available funding. It is therefore necessary to determine which areas should have a higher priority for such treatments. Similarly, when wildfires do occur there is an immediate need to determine which areas should have the highest priority for post-fire rehabilitation treatments. One criterion for allocating treatments is the potential risk of post-fire erosion, but to be effective this assessment needs to be carried out at a broad scale. This paper presents a procedure and initial results for predicting spatially-explicit, post-fire erosion risks at the hillslope scale for forest and shrub lands across the western U.S. Our approach utilizes existing physical models and datasets in a GIS framework. The model for predicting erosion is GeoWEPP, the Geographical interface for the Water Erosion Prediction Project (WEPP). The primary inputs for GeoWEPP include climate, topography, soils, and land cover/land use. Daily climate inputs were generated with Cligen, which is a stochastic weather generator distributed with WEPP. A 30-m digital elevation model, STATSGO-derived soils data, and vegetation cover were obtained from the U.S. Forest Service's LANDFIRE project. Since recent research has shown that percent ground cover is a dominant control on post-fire erosion rates, we generated a spatially-explicit map of post-fire ground cover by first using historic weather data to determine the 1000-hr fuel moisture values when fuel conditions were at 98-100% ERC (Energy Released Component). These fuel moisture values were fed into FOFEM (First Order Fire Effects Model) to obtain spatially-explicit predictions of percent ground cover, and this provided the additional land cover/land use information needed by GeoWEPP. The predicted erosion rates are comparable to measured values in the Colorado Front Range, but are much too high for the higher rainfall areas along the Pacific Coast. This pattern indicates that precipitation is having a pre-dominant effect on predicted post-fire erosion rates, especially in areas that are projected to burn at low severity. Hence the predicted erosion rates will be most useful in relative terms at the local and possibly regional scale, while comparisons between regions may be of more limited validity.
A comparative study of toluidine blue-mediated photodynamic therapy versus topical corticosteroids in the treatment of erosive-atrophic oral lichen planus: a randomized clinical controlled trial.
Jajarm, Hasan Hoseinpour; Falaki, Farnaz; Sanatkhani, Majid; Ahmadzadeh, Meysam; Ahrari, Farzaneh; Shafaee, Hooman
Recently, photodynamic therapy (PDT) has been suggested as a new treatment option that is free from side effects for erosive-atrophic oral lichen planus (OLP). The purpose of this study was to compare the effect of toluidine blue-mediated photodynamic therapy (TB-PDT) with local corticosteroids on treatment of erosive-atrophic OLP. In this randomized clinical trial, 25 patients with keratotic-atrophic-erosive oral lichen planus were allocated randomly into two groups. Group 1 (experimental): topical application of toluidine blue with micropipette was applied, and after 10Āmin, the patients were treated with a 630-nm GaAlAs laser (power density: 10ĀmW/cm(2)) during two visits. Group 2 (control) used mouthwash diluted with dexamethasone (tab 0/5 in 5Āml water) for 5Āmin, and then, it was spat out, and after 30Āmin, the mouth was rinsed with 30 drops of nystatin 100,000 units for 5Āmin and again spat out. Demographic data, type, and severity of the lesions and pain were recorded before and after treatment and then at the 1-month follow-up visit. Response rate was defined based on changes in intensity of the lesions and pain. In the experimental and control groups, sign scores of changes significantly reduced after treatment respectively (p?=?0.021) and (p?=?0.002), but between the two groups, no significant difference was observed (p?=?0.72). In the experimental (p?=?0.005) and control groups (p?=?0.001), the intensity of lesions significantly reduced after treatment and there was a significant difference between the two groups (p?=?0.001). The mean amount of improvement in pain was significantly greater in the control group compared with the experimental group (p?0.001) (??=?0.05). Our study showed that TB-PDT with laser was effective in the management of OLP. PMID:25487185
Bondugula, Srikant
to follow the original schedule or plan, inadvertently increasing the overall project cost. Many deterministic project control methods have been proposed by various researchers for calculating optimal resource schedules considering the time-cost as well...
NSDL National Science Digital Library
This brief article discusses the effect of soil and sediment erosion and its significance in social and economic aspects. The methods of measuring erosion and knowledge of past erosion rates are also briefly discussed to use as a predictor of future erosion rates.
Efficacy and safety of esomeprazole compared with omeprazole in GERD patients with erosive esophagitis: a randomized controlled trial
Joel E. Richter; Peter J. Kahrilas; John Johanson; Paul Maton; Jeffrey R. Breiter; Clara Hwang; Victoria Marino; Bernard Hamelin; Jeffrey G. Levine
OBJECTIVE:In patients with gastroesophageal reflux disease (GERD), esomeprazole, the S-isomer of omeprazole, has demonstrated pharmacological and clinical benefits beyond those seen with the racemic parent compound. This study was designed to further evaluate the efficacy and tolerability of esomeprazole relative to that of omeprazole in healing erosive esophagitis and resolving accompanying symptoms of GERD.METHODS:Esomeprazole 40 mg was compared with omeprazole
Administrative Leadership as Projection, Social Control, and Action.
ERIC Educational Resources Information Center
Reed, Donald B.
Over the past 50 years, theoretical and methodological problems have plagued the study of leadership. This paper, proposing an alternative theory, argues that leadership has three fundamental components: projection and social control, which are linked by action. Projection is the visualization of a project to be completed. Educationalģ
Self-Correcting HVAC Controls Project Final Report
Fernandez, Nicholas; Brambley, Michael R.; Katipamula, Srinivas; Cho, Heejin; Goddard, James K.; Dinh, Liem H.
This document represents the final project report for the Self-Correcting Heating, Ventilating and Air-Conditioning (HVAC) Controls Project jointly funded by Bonneville Power Administration (BPA) and the U.S. Department of Energy (DOE) Building Technologies Program (BTP). The project, initiated in October 2008, focused on exploratory initial development of self-correcting controls for selected HVAC components in air handlers. This report, along with the companion report documenting the algorithms developed, Self-Correcting HVAC Controls: Algorithms for Sensors and Dampers in Air-Handling Units (Fernandez et al. 2009), document the work performed and results of this project.
The Research on Informatization of Construction Project Cost Control
Wang Fei; Yan Juwei; Shen Bing; Huang Weijian
At present most of the domestic cost of construction enterprises still remain in control of the extensive experience of management, various business agency cost data is quite scattered, decision-makers can not have real-time dynamic cost of the project. In the information age, the use of informatization on the method of construction project costs of dynamic control is particularly important. The
Analysis and countermeasures of project cost control in construction enterprises
Xue Ai
Project cost of construction enterprises includes direct costs and indirect costs. The absence of segregation in responsibilities, the barriers exits in cost information transmitting, lack of cost control criteria, the low technological level of construction workers, lack of cost analysis and evaluation mechanism are the main problems exit in project cost control of construction enterprises. The paper puts forward countermeasures
Mechanisms of polymer degradation and erosion
Achim G÷pferich
The most important features of the degradation and erosion of degradable polymers in vitro are discussed. Parameters of chemical degradation, which is the scission of the polymer backbone, are described such as the type of polymer bond, pH and copolymer composition. Examples are given how these parameters can be used to control degradation rates. Degradation leads finally to polymer erosion,
A device for the partial removal of erosion products in stormwater runoff has been developed. The swirl concentrator as an erosion control device has been designed to concentrate the heavier soils from large flows. The concentrated underflow of up to 14 percent of the flow can be...
The Amount of Control in Offshore Software Development Projects: An Investigation of Twelve Projects
Robert Hartmann; Martin Wiener; Ulrich Remus
This paper investigates the amount of control, defined as the variety of mechanisms and their intensity of exercise in various offshore software development (OSD) projects. Using a comparative case study approach, we propose ten propositions refining the relationship between influencing factors and the amount of control. Our results confirm existing findings such as the positive relationship between project complexity\\/size and
Guidance and Control Software Project Data - Volume 1: Planning Documents
NASA Technical Reports Server (NTRS)
Hayhurst, Kelly J. (Editor)
The Guidance and Control Software (GCS) project was the last in a series of software reliability studies conducted at Langley Research Center between 1977 and 1994. The technical results of the GCS project were recorded after the experiment was completed. Some of the support documentation produced as part of the experiment, however, is serving an unexpected role far beyond its original project context. Some of the software used as part of the GCS project was developed to conform to the RTCA/DO-178B software standard, "Software Considerations in Airborne Systems and Equipment Certification," used in the civil aviation industry. That standard requires extensive documentation throughout the software development life cycle, including plans, software requirements, design and source code, verification cases and results, and configuration management and quality control data. The project documentation that includes this information is open for public scrutiny without the legal or safety implications associated with comparable data from an avionics manufacturer. This public availability has afforded an opportunity to use the GCS project documents for DO-178B training. This report provides a brief overview of the GCS project, describes the 4-volume set of documents and the role they are playing in training, and includes the planning documents from the GCS project. Volume 1 contains five appendices: A. Plan for Software Aspects of Certification for the Guidance and Control Software Project; B. Software Development Standards for the Guidance and Control Software Project; C. Software Verification Plan for the Guidance and Control Software Project; D. Software Configuration Management Plan for the Guidance and Control Software Project; and E. Software Quality Assurance Activities.
Rainfall profile characteristics in erosive and not-erosive events
NASA Astrophysics Data System (ADS)
Todisco, Francesca
In a storm the rainfall rate shows fluctuations with showers, low rain periods or rainless periods that follow one another at short or long time intervals. The intra-storm rainfall variations and event profile have been proved to have an important influence and exert a fundamental control in many field and research areas among which in runoff generation and soil erosion (Dunkerley, 2012; Frauenfeld and Truman, 2004; Mermut et al., 1997; Parsons and Stone 2006; Ran et al, 2012; Watung et al. 1996;). In particular the possibility to incorporate into simulated rain events pre-determined intensity variations, have recently driven more investigation on the effect of further intra-storm properties on the hydrograph and on the soil loss dynamic such as the position among the rainfall of the maximum rainfall intensity and of the rainless intervals (Dunkerley, 2008, 2012; El-Jabi and Sarraf, 1991; Parsons and Stone 2006; Ran et al, 2012). The objective of this paper is to derive the statistical expressions for the time distribution of erosive and not-erosive rainfalls and to describe the rainfall factors that influence the time distribution characteristics and that characterize an erosive event compared to a not erosive event. The analysis is based on the database of the experimental site of Masse (Central Italy): event soil loss and runoff volume from bare plot and climatic data, at 5 min time interval for the 5-years period 2008-2012 (Bagarello et al., 2011, Todisco et al., 2012). A total of 228 rainfall events were used in which the rainfall exceed 1 mm, 60 of which erosive. The soil is a Typic Haplustept (Soil Survey Staff, 2006) with a silty-clay-loam texture. The runs theory (Yevjevich, 1967) were applied to the rainfall events hyetograph to select the heavier ones named storms. The sequential periods with rainfall intensity above a threshold are defined as heavy intensity in series and called runs. All the rainfall events characterized by at least one run were considered as a heavy storm and included in the analysis. The rainfall event is defined as a sequence of rainless and rainy periods defined as burst. The statistical expressions for the time distribution of erosive and not-erosive rainfalls were derived and the rainfall factors that influence the time distribution characteristics and that characterize an erosive event compared to a not erosive event were identified. The time distribution of erosive and not erosive storms have been expressed as cumulative percentages of storm rainfall and storm duration to make valid comparisons between storms and to simplify analysis presentation of data. The time distribution models presented as probability distributions, provide quantitative measures of both the inter-storm variability and the general characteristics of the time sequence of precipitation in storms. Other characteristics derived and analyzed, that are pertinent in classification of storms, include the number and the duration of individual runs in the total storm period, the total severity of the runs, the location of the heaviest run in the storm period, the percentage of the total storm period that had occurred at the start and end of this run, the percentage of the total storm rainfall preceding the heaviest run, the percentage of the total storm rainfall occurring at the heaviest run, the percentage of total storm rainfall occurring at the shower that contain the heaviest run, the percentage of the total storm period during which rain actually fell. The results obtained should aid the hydrologist in design problems or other application such as: the design of experiments for soil erosion study corresponding with the comparable measures of natural events (Agassi et al., 1999; Dunkerley, 2008; Kinnell, 2005; Mathys et al., 2005;) both in intra-storm dynamic and overall characteristics (Hanke et al., 2004); or the extrapolation of the erosive event inter-storm characteristics in which the time distribution is a pertinent factor.
Project W-049H instrument and control Acceptance Test Procedure
Carrigan, M.C.
The purpose of this Acceptance Test Procedure (ATP) for the Project W-049H, Treated Effluent Disposal Facility, is to verify that the instrument and control systems have been installed in accordance with the design documents and function as required by the project criteria. The instrument and control system includes three operator control stations, modems, and general purpose LAN interface cabinets in the Effluent Treatment Facility control room; two pump stations; disposal station pumping building; and all local control units installed in the fold. Testing will be performed using actual signals when available and simulated signals when actual signals are unavailable.
Technology Transfer Automated Retrieval System (TEKTRAN)
This manuscript is a chapter for the Encyclopedia of Soils in the Environment on Wind Erosion. The chapter includes discussion of the wind profile, modes of particle transportation, soil surface conditions, effect of vegetation, wind erosion modeling, sampling, use of radioisotope tracers to estimat...
NSDL National Science Digital Library
Abbey Payeur
This activity is a field investigation where students find real-life examples of erosion in their school surroundings. Students will extend what they learned during stream table lessons about erosion, deposition, deltas, meandering streams, and dams.
Relationship of runoff, erosion and sediment yield to weather types in the Iberian Peninsula
NASA Astrophysics Data System (ADS)
Nadal-Romero, E.; Gonzßlez-Hidalgo, J. C.; Cortesi, N.; Desir, G.; G¾mez, J. A.; Lasanta, T.; LucĒa, A.; MarĒn, C.; MartĒnez-Murillo, J. F.; Pacheco, E.; RodrĒguez-Blanco, M. L.; Romero DĒaz, A.; Ruiz-Sinoga, J. D.; Taguas, E. V.; Taboada-Castro, M. M.; Taboada-Castro, M. T.; ┌beda, X.; Zabaleta, A.
Precipitation has been recognized as one of the main factors driving soil erosion and sediment yield (SY), and its spatial and temporal variability is recognized as one of the main reasons for spatial and temporal analyses of soil erosion variability. The weather types (WTs) approach classifies the continuum of atmospheric circulation into a small number of categories or types and has been proven a good indicator of the spatial and temporal variability of precipitation. Thus, the main objective of this study is to analyze the relationship between WTs, runoff, soil erosion (measured in plots), and sediment yield (measured in catchments) in different areas of the Iberian Peninsula (IP) with the aim of detecting spatial variations in these relationships. To this end, hydrological and sediment information covering the IP from several Spanish research teams has been combined, and related with daily WTs estimated by using the NMC/NCAR 40-Year Reanalysis Project. The results show that, in general, a few WTs (particularly westerly, southwesterly and cyclonic) provide the largest amounts of precipitation; and southwesterly, northwesterly and westerly WTs play an important role in runoff generation, erosion and sediment yield as they coincide with the wettest WTs. However, this study highlights the spatial variability of erosion and sediment yield in the IP according to WT, differentiating (1) areas under the influence of north and/or north-westerly flows (the north coast of Cantabria and inland central areas), (2) areas under the influence of westerly, southwesterly and cyclonic WTs (western and southwestern IP), (3) areas in which erosion and sediment yield are controlled by easterly flows (Mediterranean coastland), and (4) lastly, a transitional zone in the inland northeast Ebro catchment, where we detected a high variability in the effects of WTs on erosion. Overall results suggest that the use of WTs derived from observed atmospheric pressure patterns could be a useful tool for inclusion in future projections of the spatial variability of erosion and sediment yield, as models capture pressure fields reliably.
Proceedings, 2001National Conference on Beach Preservation Technology, pp. 274-283 COASTAL INLET BANK EROSION
US Army Corps of Engineers
BANK EROSION William C. Seabergh 1 Abstract: Much focus is placed on beach erosion on the open coast erosion. These shorelines lie adjacent to coastal inlets and extend around the inlet from the ocean to bay shoreline develop inner-bank erosion in the absence of preventive measures. Many mature projects show eroded
15 CFR 923.25 - Shoreline erosion/mitigation planning.
Code of Federal Regulations, 2014 CFR
...2014-01-01 2014-01-01 false Shoreline erosion/mitigation planning. 923.25 Section...Management Areas ¦ 923.25 Shoreline erosion/mitigation planning. (a) The...control, or lessen the impact of, shoreline erosion, including potential impacts of...
15 CFR 923.25 - Shoreline erosion/mitigation planning.
Code of Federal Regulations, 2013 CFR
...2013-01-01 2013-01-01 false Shoreline erosion/mitigation planning. 923.25 Section...Management Areas ¦ 923.25 Shoreline erosion/mitigation planning. (a) The...control, or lessen the impact of, shoreline erosion, including potential impacts of...
15 CFR 923.25 - Shoreline erosion/mitigation planning.
Code of Federal Regulations, 2012 CFR
...2012-01-01 2012-01-01 false Shoreline erosion/mitigation planning. 923.25 Section...Management Areas ¦ 923.25 Shoreline erosion/mitigation planning. (a) The...control, or lessen the impact of, shoreline erosion, including potential impacts of...
15 CFR 923.25 - Shoreline erosion/mitigation planning.
Code of Federal Regulations, 2011 CFR
...2011-01-01 2011-01-01 false Shoreline erosion/mitigation planning. 923.25 Section...Management Areas ¦ 923.25 Shoreline erosion/mitigation planning. (a) The...control, or lessen the impact of, shoreline erosion, including potential impacts of...
Erosion and Sedimentation as Part of the Natural System1
Standiford, Richard B.
Erosion and Sedimentation as Part of the Natural System1 Robert B. Howard2 1 Presented Forest and Range Experiment Station, Forest Service, U.S. Department of Agriculture; 1982. 403 Erosion of erosion or sedimentation however differs from one environment to another. Various factors control
The management submodel of the Wind Erosion Prediction System
Technology Transfer Automated Retrieval System (TEKTRAN)
The Wind Erosion Prediction System (WEPS) is a process-based, daily time-step, computer model that predicts soil erosion via simulation of the physical processes controlling wind erosion. WEPS is comprised of several individual modules (submodels) that reflect different sets of physical processes, ...
NASA Technical Reports Server (NTRS)
Falco, L.; Cushini, A.
Apparatus for measuring the resistance of materials to erosion is examined and a scheme for standardization of the test parameters is described. Current materials being used for protecting aircraft parts from erosion are surveyed, their chief characteristics being given. The superior properties of urethane coatings are pointed out. The complete cycle for painting areas subject to erosion is described.
The following is a final report for the Clear Lake Basin 2000 project. All of the major project construction work was complete and this phase generally included final details and testing. Most of the work was electrical. Erosion control activities were underway to prepare for the rainy season. System testing including pump stations, electrical and computer control systems was conducted. Most of the project focus from November onward was completing punch list items.
Improving soil bioengineering techniques to control erosion and sedimentation within the context of torrential Mediterranean climate: a French-Canadian experience
NASA Astrophysics Data System (ADS)
Rey, Freddy; Louis, Sķverine; Burylo, Mķlanie; Raymond, Pierre
On marly eroded terrains of the French Southern Alps, many researches are undertaken in order to better understand the role of vegetation and bioengineering works on erosion and sedimentation control. To this view, the eroded marly gullies of the French Southern Alps are an experimental design where an original French strategy of rehabilitation, developed by scientists from Irstea (ex-Cemagref), has been tested since 2002. It is comprised of the construction of bioengineering works, namely of "brush layers and brush mats of cuttings on deadwood microdams", and implements the use of willow cuttings (Salix purpurea and S. incana). The main objective of these works is to sustainably trap and retain marly sediment, by checking their performance (growth and survival of the cuttings, sediment trapping) in a mountainous and Mediterranean climate. In Canada, several private companies have developed their own knowledge and expertise in the conception and building of bioengineering works for erosion control, especially in the context of hilly and mountainous landscapes and climates. Therefore, it was decided to use the competence and expertise of Terra Erosion Control Ltd., a Canadian company, in the French torrential Mediterranean climate. Ten modalities were tested, the aims being to develop and/or to modify existing designs of current techniques, to experiment with other live cuttings (Populus nigra) and rooted species (Alnus spp. and Hippophae spp.), to evaluate and compare the potential use of different organic soil amendments in order to increase beneficial soil microorganisms and finally, to evaluate the potential use of specialized tools and equipment in order to increase the efficiency of the installation for vegetation establishment and sediment trapping, while decreasing the implementation costs. The experimental design was installed in March 2011 and the early observations in Spring 2012 showed that: 1/ most of the cuttings and the plants resisted to burial and to drought conditions; in particular, the structures using wooden boards instead of locally harvested logs appeared to be holding up well; 2/ designs of current techniques with vertical cuttings were better for resprouting and sediment trapping; 3/ 0.8m live cuttings of Populus nigra may represent an alternative to Salix spp., but resprout appeared lower; 4/ it was not possible to evaluate the performance of rooted species (Alnus spp. and Hippophae spp.); therefore more experiment is needed, especially with longer plants; 5/ organic soil amendments may increase vegetation development (BRF > fertilizer > compost > mixes). By comparing the results with similar sites used as benchmarks, installed since 2002, further observations in the spring of 2013 will allow us to evaluate the efficiency of the different modalities to improve vegetation establishment and sediment trapping.
Supporting the Future Air Traffic Control Projection Process
Davison, H. J.
In air traffic control, projecting what the air traffic situation will be over the next 30 seconds to 30 minutes is a key process in identifying conflicts that may arise so that evasive action can be taken upon discovery ...
This report presents results of the Mine Waste Technology Program Activity III, Project 8, Underground Mine Source Control Demonstration Project implemented and funded by the U. S. Environmental Protection Agency (EPA) and jointly administered by EPA and the U. S. Department of E...
Projective synchronization in fractional order chaotic systems and its control
Chunguang Li
The chaotic dynamics of fractional (non-integer) order systems have begun to attract much attention in recent years. In this paper, we study the projective synchronization in two coupled fractional order chaotic oscillators. It is shown that projective synchronization can also exist in coupled fractional order chaotic systems. A simple feedback control method for controlling the scaling factor onto a desired value is also presented.
MILA Antenna Control Unit Replacement Project
NASA Technical Reports Server (NTRS)
Bresette, Jeremy
The Air to Ground Subsystem (AGS) Antenna Control Units at the MILA Ground Network Tracking Station are at end-of-life and are being replaced. AGS consists of two antennas at MILA (Quad-Helix and Teltrac). Software was taken from the existing Subsystem Controller and modified for the Antenna Control Unit (ACU). The software is capable of receiving and sending commands to and from the ACU. Moving the azimuth clockwise, counterclockwise, moving the elevation up or down, turning servo power on and off, and inputting azimuth and elevation angles are commands that the antenna can receive.
Project impact analysis as an optimal control problem
Anandalingam, G.
This paper analyzes the effects of a major investment project on a multi-sector less developed economy. Single investment projects with external effects reaching across the entire economy are frequently encountered in developing countries. This study concentrates on the Mahaweli Ganga Development Project in Sri Lanka, a multi-dam irrigation and hydroelectric power project. The Mahaweli Project calls for an annual investment level, in 1970 prices, of Rs 2200 million (US $150 million) over a period of six years, which is 50 percent of the annual expenditure of the government. The project would thus require a large fraction of total investment over a medium term planning period and would materially alter the existing supply and demand for major goods and services. The project is sufficiently large that its effect is economy-wide. The model we use is a dynamic input-output optimizing model having the mathematical structure of an Optimal Control problem.
Supporting the Future Air Traffic Control Projection Process
NASA Technical Reports Server (NTRS)
Davison, Hayley J.; Hansman, R. John, Jr.
In air traffic control, projecting what the air traffic situation will be over the next 30 seconds to 30 minutes is a key process in identifying conflicts that may arise so that evasive action can be taken upon discovery of these conflicts. A series of field visits in the Boston and New York terminal radar approach control (TRACON) facilities and in the oceanic air traffic control facilities in New York and Reykjavik, Iceland were conducted to investigate the projection process in two different ATC domains. The results from the site visits suggest that two types of projection are currently used in ATC tasks, depending on the type of separation minima and/or traffic restriction and information display used by the controller. As technologies improve and procedures change, care should be taken by designers to support projection through displays, automation, and procedures. It is critical to prevent time/space mismatches between interfaces and restrictions. Existing structure in traffic dynamics could be utilized to provide controllers with useful behavioral models on which to build projections. Subtle structure that the controllers are unable to internalize could be incorporated into an ATC projection aid.
Guidance and Control Software Project Data - Volume 3: Verification Documents
NASA Technical Reports Server (NTRS)
Hayhurst, Kelly J. (Editor)
The Guidance and Control Software (GCS) project was the last in a series of software reliability studies conducted at Langley Research Center between 1977 and 1994. The technical results of the GCS project were recorded after the experiment was completed. Some of the support documentation produced as part of the experiment, however, is serving an unexpected role far beyond its original project context. Some of the software used as part of the GCS project was developed to conform to the RTCA/DO-178B software standard, "Software Considerations in Airborne Systems and Equipment Certification," used in the civil aviation industry. That standard requires extensive documentation throughout the software development life cycle, including plans, software requirements, design and source code, verification cases and results, and configuration management and quality control data. The project documentation that includes this information is open for public scrutiny without the legal or safety implications associated with comparable data from an avionics manufacturer. This public availability has afforded an opportunity to use the GCS project documents for DO-178B training. This report provides a brief overview of the GCS project, describes the 4-volume set of documents and the role they are playing in training, and includes the verification documents from the GCS project. Volume 3 contains four appendices: A. Software Verification Cases and Procedures for the Guidance and Control Software Project; B. Software Verification Results for the Pluto Implementation of the Guidance and Control Software; C. Review Records for the Pluto Implementation of the Guidance and Control Software; and D. Test Results Logs for the Pluto Implementation of the Guidance and Control Software.
Evaluation of the Serum Zinc Level in Erosive and Non-Erosive Oral Lichen Planus
Gholizadeh, N.; Mehdipour, M.; Najafi, Sh.; Bahramian, A.; Garjani, Sh.; Khoeini Poorfar, H.
Statement of Problem: Lichen planus is a chronic inflammatory immunologic-based disease involving skin and mucosa. This disease is generally divided into two categories: erosive and non-erosive. Many etiologic factors are deliberated regarding the disease; however, the disorders of immune system and the role of cytotoxic T-lymphocytes and monocytes are more highlighted. Zinc is an imperative element for the growth of epithelium and its deficiency induces the cytotoxic activity of T-helper2 cells, which seems to be associated with lichen planus. Purpose: This study was aimed to evaluate the levels of serum zinc in erosive and non-erosive oral lichen planus (OLP) and to compare it with the healthy control group to find out any feasible inference. Materials and Method: A total of 22 patients with erosive oral lichen planus, 22 patients with non erosive OLP and 44 healthy individuals as the control group were recruited in this descriptive-comparative study. All the participants were selected from the referees to the department of oral medicine, school of dentistry, Tabriz University of Medical Sciences. Serum zinc level was examined for all the individuals with liquid-stat kit (Beckman Instruments Inc.; Carlsbad, CA). Data were analyzed by adopting the ANOVA and Tukey tests, using SPSS 16 statistical software. Results: The mean age of patients with erosive and non-erosive LP was 41.7 and 41.3 years, respectively. The mean age of the healthy control group was 34.4 years .The mean serum zinc levels in the erosive and non erosive lichen planus groups and control groups were 8.3 (1.15), 11.15 (0.92) and 15.74 (1.75) ?g/dl respectively. The difference was statistically significant (p< 0.05). Conclusion: The serum zinc levels were decreased in patients with erosive oral lichen planus. This finding may probably indicate the promising role of zinc in development of oral lichen planus. PMID:24883340
Soil Erosion Protection Potential of Young Paulownia Plantation
NASA Astrophysics Data System (ADS)
Stepchich, Avgusta; Djodjov, Christo
Soil erosion is removal of soil and rock particles by water, wind, ice and gravity. It is widely recognized as a global soil threat. Soils impacted by different forms of erosion cover large areas around the world. While landscape, soil and climate conditions trigger soil erosion processes, the vegetation cover reduces the soil erosion risk. About 60 % of the area of agricultural land in Bulgaria is under erosion risk, which necessitates implementation of series of measures for soil erosion control. The aim of this study is to determine the erosion protection potential and the loss of soil nutrients of young Paulownia plantation. Field experiments have been set up under unirrigated conditions at the experimental field for soil erosion studies of the N. Poushkarov Institute of Soil Science, Agrotechnology and Plant Protection near Suhodol. The local soils are Chromic Luvisols, moderately eroded. The altitude is 750 m and the slope gradient is 80. The experiment consists of four field plots for soil erosion studies, three of which planted with Paulownia Bellissima and a reference one with bare soil. The plants have been planted at a distance of 2 m between adjacent rows and 1 m between each two plants within the row. The size of each field plot is 32 m2 (4 m width and 8 m length). The plots are equipped with containers for collecting the surface runoff caused by erosive rainfall events. Biometrics, including the root-striking of the plants, their growth in height, foliage cover (projection) and stem diameter, was studied from May 13th to October 21st. The data reported cover the results from the studies during the first vegetation period after planting in the Spring of 2013. During the year four erosive rainfalls were observed with a total amount of 79.2 mm, resulting to a total amount of soil loss of 772 kg/ha from a planted plot and 551 kg/ha from bear soil. The total surface runoff is 156.7 m3/ha from planted plot and 153.1 m3/ha from bare soil. The total losses of N-NO3- are 0.994 kg/ha from plated plots and 0.718 kg/ha from bare soils and the losses of N-NH4+ are respectively 0.042 and 0.117 kg/ha. The results from biometrics showed that 58 % of the plants were found to have stroken roots; an average growth of 0.3 m and a mean increase in the number of leaves with 3 were recorded. The results reported here show that the losses of soil and nutrients from the field plots planted with Paulownia Bellissima are about 40 % higher than these from the plot with bare soil. This discouraging result needs further experimental and theoretical analyses. The research throughout the following years will give further information about the soil erosion protection potential of young Paulownia plantation.
Controlled Hydrogen Fleet and Infrastructure Demonstration Project
Dr. Scott Staley
This program was undertaken in response to the US Department of Energy Solicitation DE-PS30-03GO93010, resulting in this Cooperative Agreement with the Ford Motor Company and BP to demonstrate and evaluate hydrogen fuel cell vehicles and required fueling infrastructure. Ford initially placed 18 hydrogen fuel cell vehicles (FCV) in three geographic regions of the US (Sacramento, CA; Orlando, FL; and southeast Michigan). Subsequently, 8 advanced technology vehicles were developed and evaluated by the Ford engineering team in Michigan. BP is Ford's principal partner and co-applicant on this project and provided the hydrogen infrastructure to support the fuel cell vehicles. BP ultimately provided three new fueling stations. The Ford-BP program consists of two overlapping phases. The deliverables of this project, combined with those of other industry consortia, are to be used to provide critical input to hydrogen economy commercialization decisions by 2015. The program's goal is to support industry efforts of the US President's Hydrogen Fuel Initiative in developing a path to a hydrogen economy. This program was designed to seek complete systems solutions to address hydrogen infrastructure and vehicle development, and possible synergies between hydrogen fuel electricity generation and transportation applications. This project, in support of that national goal, was designed to gain real world experience with Hydrogen powered Fuel Cell Vehicles (H2FCV) 'on the road' used in everyday activities, and further, to begin the development of the required supporting H2 infrastructure. Implementation of a new hydrogen vehicle technology is, as expected, complex because of the need for parallel introduction of a viable, available fuel delivery system and sufficient numbers of vehicles to buy fuel to justify expansion of the fueling infrastructure. Viability of the fuel structure means widespread, affordable hydrogen which can return a reasonable profit to the fuel provider, while viability of the vehicle requires an expected level of cost, comfort, safety and operation, especially driving range, that consumers require. This presents a classic 'chicken and egg' problem, which Ford believes can be solved with thoughtful implementation plans. The eighteen Ford Focus FCV vehicles that were operated for this demonstration project provided the desired real world experience. Some things worked better than expected. Most notable was the robustness and life of the fuel cell. This is thought to be the result of the full hybrid configuration of the drive system where the battery helps to overcome the performance reduction associated with time related fuel cell degradation. In addition, customer satisfaction surveys indicated that people like the cars and the concept and operated them with little hesitation. Although the demonstrated range of the cars was near 200 miles, operators felt constrained because of the lack of a number of conveniently located fueling stations. Overcoming this major concern requires overcoming a key roadblock, fuel storage, in a manner that permits sufficient quantity of fuel without sacrificing passenger or cargo capability. Fueling infrastructure, on the other hand, has been problematic. Only three of a planned seven stations were opened. The difficulty in obtaining public approval and local government support for hydrogen fuel, based largely on the fear of hydrogen that grew from past disasters and atomic weaponry, has inhibited progress and presents a major roadblock to implementation. In addition the cost of hydrogen production, in any of the methodologies used in this program, does not show a rapid reduction to commercially viable rates. On the positive side of this issue was the demonstrated safety of the fueling station, equipment and process. In the Ford program, there were no reported safety incidents.
ANG coal gasification project management control system report. [Great Plains project
Not Available
Much time, money and effort has been spent in the forefront of this project for project controls. The work breakdown structure for the systems has been custom designed. The systems, both manual and computerized, have been well scrutinized and chosen by ANG to represent the most cost effective and efficient way of controlling a project the magnitude of $1.5 billion. These systems have been developed in a manner so that information can be gathered as detailed or as summarized as necessary, and in the most timely and expeditious ways.
Cultivating Systemic Capacity: The Rhode Island Tobacco Control Enhancement Project
Paul Florin; Carolyn Celebucki; John Stevenson; Jasmine Mena; Dawn Salago; Andrew White; Betty Harvey; Marianela Dougal
This paper describes the Rhode Island Tobacco Control Enhancement Project (TCEP), a state-university-community technical assistance system. TCEP was developed under the auspices of the Rhode Island Department of Health's Tobacco Control program and was designed to build capacity among nine community-based organizations to mount comprehensive tobacco control interventions in five diverse communities within the state. This paper: (1) provides a
Apollo Soyuz Test Project photographic processing control plan
NASA Technical Reports Server (NTRS)
Lockwood, H. E.
The laboratory controls to be used within the photographic technology division (PTD) for processing original space flight films exposed on the Apollo Soyuz Test Project mission are specified. The sensitometric exposures to be used by PTD for certifying processes, for exposing Houston Controls, and for preflight and postflight exposures on original films as well as procedures for film certification are described. Processing conditions used to achieve each control and processing machine operating parameters are included.
Overview of NASA's Thermal Control Technology Development Project
NASA Technical Reports Server (NTRS)
Stephan, Ryan A.
NASA?s Constellation Program included the Orion, Altair, and Lunar Surface Systems project offices. The first two elements, Orion and Altair, were planned to be manned space vehicles while the third element was much broader and included several sub-elements including Rovers and a Lunar Habitat. The planned missions involving these systems and vehicles included several risks and design challenges. Due to the unique thermal operating environment, many of these risks and challenges were associated with the vehicles? thermal control system. NASA?s Exploration Technology Development Program (ETDP) consisted of several technology development projects. The project chartered with mitigating the aforementioned thermal risks and design challenges was the Thermal Control System Development for Exploration Project. These risks and design challenges were being addressed through a rigorous technology development process that was planned to culminate with an integrated thermal control system test. Although these Constellation elements have been cancelled or significantly changed, the thermal technology development process is being continued within a new program entitled Enabling Technology Development and Demonstration (ETDD). The current paper summarizes the development efforts being performed by the technology development project. The development efforts involve heat acquisition and heat rejection hardware including radiators, heat exchangers, and evaporators. The project has also been developing advanced phase change material heat sinks and performing a material compatibility assessment for a promising thermal control system working fluid. The to-date progress and lessons-learned from these development efforts will be discussed throughout the paper.
Overview of NASA's Thermal Control System Development for Exploration Project
NASA Technical Reports Server (NTRS)
Stephan, Ryan A.
NASA's Constellation Program includes the Orion, Altair, and Lunar Surface Systems project offices. The first two elements, Orion and Altair, are manned space vehicles while the third element is broader and includes several sub-elements including Rovers and a Lunar Habitat. The upcoming planned missions involving these systems and vehicles include several risks and design challenges. Due to the unique thermal environment, many of these risks and challenges are associated with the vehicles' thermal control system. NASA's Exploration Systems Mission Directorate (ESMD) includes the Exploration Technology Development Program (ETDP). ETDP consists of several technology development projects. The project chartered with mitigating the aforementioned risks and design challenges is the Thermal Control System Development for Exploration Project. The risks and design challenges are addressed through a rigorous technology development process that culminates with an integrated thermal control system test. The resulting hardware typically has a Technology Readiness Level (TRL) of six. This paper summarizes the development efforts being performed by the technology development project. The development efforts involve heat acquisition and heat rejection hardware including radiators, heat exchangers, and evaporators. The project has also been developing advanced phase change material heat sinks and performing assessments for thermal control system fluids.
Irsogladine maleate and rabeprazole in non-erosive reflux disease: A double-blind, placebo-controlled study
Suzuki, Takayoshi; Matsushima, Masashi; Masui, Aya; Tsuda, Shingo; Imai, Jin; Nakamura, Jun; Tsukune, Yoko; Uchida, Tetsufumi; Yuhara, Hiroki; Igarashi, Muneki; Koike, Jun; Mine, Tetsuya
AIM: To evaluate the efficacy of adding irsogladine maleate (IM) to proton-pump inhibitor (PPI) therapy in non-erosive reflux disease (NERD) treatment. METHODS: One hundred patients with NERD were recruited and randomized to receive rabeprazole plus IM (group I) or rabeprazole plus placebo (group P). The efficacy of the treatment was assessed using the Frequency Scale for the Symptoms of Gastroesophageal Reflux Disease (FSSG) and the short form (SF)-36 quality of life questionnaires after four weeks of treatment. We also assessed whether patients with NERD with minimal changes (grade M) had different responses to the therapies compared with patients who did not have minimal changes (grade N). RESULTS: Group I and group P showed significant improvements in their FSSG scores after the treatment (from 17.9 ▒ 7.9 to 9.0 ▒ 7.6, and from 17.7 ▒ 7.3 to 11.2 ▒ 7.9, respectively, P = 0.0001), but there was no statistically significant difference between the FSSG scores in group I and those in group P. Subgroup analysis showed that significant improvements in the FSSG scores occurred in the patients in group I who had NERD grade N (modified Los Angeles classification) (7.8 ▒ 7.4 vs 12.5 ▒ 9.8, P = 0.041). The SF-36 scores for patients with NERD grade N who had received IM and rabeprazole were significantly improved in relation to their vitality and mental health scores. CONCLUSION: The addition of IM to rabeprazole significantly improves gastroesophageal reflux disease symptoms and the quality of the lives of patients with NERD grade N. PMID:25945018
NSDL National Science Digital Library
In this multi-station lab, learners conduct a series of experiments to explore the processes and effects of weathering and erosion. Using the results from these explorations, learners design and conduct an experiment comparing the rate of erosion in different biomes. Use this activity to teach weathering and erosion, and also to illustrate how scientists often use the results of one experiment to inspire another. This activity is intended to be conducted over multiple meetings.
Numerical simulation of the erosion in the 90░ elbow
NASA Astrophysics Data System (ADS)
Deng, Yunzhong; Liu, Yinhe; Chen, Jianying; Zhang, Yongjian
In the process of natural gas transportation, cement production and coal-fired power, the gas-solid two-phase flow exists widely in pipelines. The existence of solid particles may cause the erosion of the pipeline, especially in the elbow of the pipeline. Equations used to predict erosion rate are usually obtained from well-controlled experimental tests for solid particles carried in a gas or liquid flow. The particle impact speed and impact angle affect the erosion process and are two major parameters in most erosion equations. In this paper, the erosion of 90░ elbow was studied by using Computational Fluid Dynamics (CFD), Discrete Particle Model (DPM) and erosion equations. The maximum erosion rate and the erosion position were reported. Particle size does not influence the erosion rate when particle size is bigger than a certain degree. When the mass ratio of sand loading to fluid is less than 1, erosion ratio is proportional to the loading mass. The erosion rate is lower for larger radius elbow, and the erosion rate is greatly declined by using the plugged tee instead of an elbow.
NASA Technical Reports Server (NTRS)
2003-01-01[figure removed for brevity, see original site] Released 22 April 2003Streamlined buttes and mesas are left as remnants of an erosive wind that has carried away sediments and even the rim of a small crater. Two wind directions are apparent in the buttes and mesas that cross each other at 90 degrees. Small dark dunes wind their way between the remnant towers, indicating that the work of the wind is an ongoing process.Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.Image information: VIS instrument. Latitude 5.3, Longitude 350.1 East (9.9 West). 19 meter/pixel resolution.
Overview of NASA's Thermal Control System Development for Exploration Project
NASA Technical Reports Server (NTRS)
Stephan, Ryan A.
The now-cancelled Constellation Program included the Orion, Altair, and Lunar Surface Systems project offices. The first two elements, Orion and Altair, were planned to be manned space vehicles while the third element was much more diverse and included several sub-elements. Among other things, these sub-elements were Rovers and a Lunar Habitat. The planned missions involving these systems and vehicles included several risks and design challenges. Due to the unique thermal operating environment, many of these risks and challenges were associated with the vehicles thermal control system. NASA s Exploration Technology Development Program (ETDP) consisted of various technology development projects. The project chartered with mitigating the aforementioned thermal risks and design challenges was the Thermal Control System Development for Exploration Project. These risks and design challenges were being addressed through a rigorous technology development process that was planned to culminate with an integrated thermal control system test. Although the technologies being developed were originally aimed towards mitigating specific Constellation risks, the technology development process is being continued within a new program. This continued effort is justified by the fact that many of the technologies are generically applicable to future spacecraft thermal control systems. The current paper summarizes the development efforts being performed by the technology development project. The development efforts involve heat acquisition and heat rejection hardware including radiators, heat exchangers, and evaporators. The project has also been developing advanced phase change material heat sinks and performing a material compatibility assessment for a promising thermal control system working fluid. The to-date progress and lessons-learned from these development efforts will be discussed throughout the paper.
Erosion and Sediment Damages and Economic Impacts of Potential 208 Controls: A Summary of Five Watershed Studies in TexasĀ
Taylor, C. R.; Reneau, D. R.; Harris, B. L.
consequences of various sedimentation control options. These topics were joined in the studies because they deal with different facets of the same problem. Unlike some potential pollutants, soil particles transported from a farmer's field that may become a...
D. J. Hanslow; A. Gissing
Approximately two thirds of the NSW open ocean coastline is characterised by sandy beaches. These beaches are highly dynamic, undergoing continual cycles of erosion and accretion in response to the variation of tides, wind and waves. In many places existing foreshore development has been built within the active beach system and is at risk from coastal erosion. With current predictions
Coastal Erosion Online Discussion
NSDL National Science Digital Library
Sheila Roberts
The students are given the following: Read the articles below about erosion along the Lake Erie shoreline and discuss them. What causes the erosion? What can be done to prevent erosion? Should people be allowed to build structures to protect their property from erosion? Should people be allowed to live along the shoreline in high erosion areas? Students are expected to have completed the coastal erosion module (read text book, view powerpoint lecture and take a quiz) and read articles regarding coastal erosion along the Lake Erie coastline. In the online discussion, students must show that they understand coastal processes, the impact of man made structures on coastal processes, and can apply their values as they discuss what should be done, if anything, to reduce the impact of coastal erosion. Teaching Tips Adaptations that allow this activity to be successful in an online environment This was designed as an online activity. I have also used it in face-to-face courses (students participate in online discussion prior to in-class discussion). Elements of this activity that are most effective This gets students thinking about how what they learn in class can be used to solve real problems faced by the local community and/or the world. Although some students propose impractical solutions, they are at least thinking. Recommendations for other faculty adapting this activity to their own course: Find local issues and/or global issues that show how geology can be used to solve problems.
Introduction to tillage erosion
Technology Transfer Automated Retrieval System (TEKTRAN)
Tillage as a source of erosion Tillage erosion is the downslope movement of soil by tillage. During tillage, soil is lifted and gravity moves soil downslope. Soil movement by tillage increases with slope steepness. However, net soil transport by tillage is determined by the change in slope. Soil mov...
William C. Seabergh
Much focus is placed on beach erosion on the open coast. However, coastal processes often occur on sandy shorelines interior to inlets that can lead to severe erosion. These shorelines lie adjacent to coastal inlets and extend around the inlet from the ocean to bay. In particular, an examination of coastal inlets with jetties or terminal groins that are connected
Environmental Impact Statement Truckee Meadows Flood Control Project
US Army Corps of Engineers
DRAFT Environmental Impact Statement for the Truckee Meadows Flood Control Project Nevada General Reevaluation Report Volume I Ł Draft Environmental Impact Statement prepared by U.S. Army Corps of Engineers Sacramento District May 2013 #12;#12;DRAFT Environmental Impact Statement for the Truckee Meadows Flood
TRUCKEE MEADOWS FLOOD CONTROL PROJECT, NEVADA 17 December 2013
US Army Corps of Engineers
TRUCKEE MEADOWS FLOOD CONTROL PROJECT, NEVADA 17 December 2013 ABSTRACT: The Truckee Meadows Flood economically infeasible. In 1996, local communities requested that flooding problems in Truckee Meadows-sensitive, and technically feasible flood risk management and related recreation for the Cities of Reno and Sparks, Nevada
Instrumentation and control for Rajasthan Atomic Power Project: construction aspect
Rama Rao; V. V. K
The construction aspects of instrumentation and control systems for ; Rajasthan Atomic Power Project are described. Total quantities of instruments, ; stainless steel tubing and fittings, copper tubing, cabling and junctions for ; RAPP-1 are given. The costs for equipment and installation are mentioned. All ; instruments are inspected, tested and calibrated before installation. Schedules ; of installation with respect
Erosion of soil organic carbon: implications for carbon sequestration
Van Oost, Kristof; Van Hemelryck, Hendrik; Harden, Jennifer W.
Agricultural activities have substantially increased rates of soil erosion and deposition, and these processes have a significant impact on carbon (C) mineralization and burial. Here, we present a synthesis of erosion effects on carbon dynamics and discuss the implications of soil erosion for carbon sequestration strategies. We demonstrate that for a range of data-based parameters from the literature, soil erosion results in increased C storage onto land, an effect that is heterogeneous on the landscape and is variable on various timescales. We argue that the magnitude of the erosion term and soil carbon residence time, both strongly influenced by soil management, largely control the strength of the erosion-induced sink. In order to evaluate fully the effects of soil management strategies that promote carbon sequestration, a full carbon account must be made that considers the impact of erosion-enhanced disequilibrium between carbon inputs and decomposition, including effects on net primary productivity and decomposition rates.
Potential for monitoring soil erosion features and soil erosion modeling components from remotely sensed data
NASA Technical Reports Server (NTRS)
Langran, K. J.
Accurate estimates of soil erosion and its effects on soil productivity are essential in agricultural decision making and planning from the field scale to the national level. Erosion models have been primarily developed for designing erosion control systems, predicting sediment yield for reservoir design, predicting sediment transport, and simulating water quality. New models proposed are more comprehensive in that the necessary components (hydrology, erosion-sedimentation, nutrient cycling, tillage, etc.) are linked in a model appropriate for studying the erosion-productivity problem. Recent developments in remote sensing systems, such as Landsat Thematic Mapper, Shuttle Imaging Radar (SIR-B), etc., can contribute significantly to the future development and operational use of these models.
33 CFR 263.23 - Small flood control project authority (Section 205).
Code of Federal Regulations, 2010 CFR
...2010-07-01 2010-07-01 false Small flood control project authority (Section 205...OF DEFENSE CONTINUING AUTHORITIES PROGRAMS Flood Control Policy ¦ 263.23 Small flood control project authority (Section...
33 CFR 263.23 - Small flood control project authority (Section 205).
Code of Federal Regulations, 2011 CFR
...2011-07-01 2011-07-01 false Small flood control project authority (Section 205...OF DEFENSE CONTINUING AUTHORITIES PROGRAMS Flood Control Policy ¦ 263.23 Small flood control project authority (Section...
Plant materials and amendments for controlling wind and water erosion on a fly ash disposal area: TVA Colbert Fossil Plant, Alabama
Maddox, J.J.; Behel, D.; Soileau, J.M.; Kelsoe, J.
Fly ash disposal sites adjacent to fossil fueled generating plants are subject to wind and water erosion which increases the operation and maintenance costs. Gullies and unstable areas in the disposal sites require expensive leveling and filling practices. Test evaluated both warm- and cool-season cover crops established by either sod or seed. Amendments to the ash consisted of composted poultry litter (CPL), soil, soil+CPL, fertilizer and beneficial soil microbes including mycorrhizal fungi. Turf sods (419 Bermuda, Emerald zoysia, and Raleigh St. Augustine) were compared in greenhouse and field studies. Six legumes and 12 grass species were tested in the greenhouse as seeded cover crops using similar amendments and raw poultry litter (PL). Legumes grew better with CPL and Boil amendments and grasses grew better on PL and soil amendments possibly due to differences in N requirements and N supply. Cool season crops generally grew faster than warm season species in the greenhouse tests. Amendments should be mixed with the FA to ameliorate the effects of boron and salt toxicity and to increase the water holding capacity. Bermuda sod grew faster than either St, Augustine or Emerald zoysia, but requires more water. A microbial amendment increased dry matter yields of bermuda sod 2 to 3 times after 40 to 60 days over unamended controls. Microbial amendments may be justified on an economic and sustainable basis. A field study is assessing the environmental and cultural requirements to grow a cover crop on an annual basis.
Comparison of growth performance of Lolium perenne L., Dactylis glomerata L. and Agropyron elongatum (Host.) P. Beauv. for erosion control in Turkey.
G÷kbulak, Ferhat
This study was carried out in plastic containers to compare growth performances of perennial ryegrass, orchardgrass and tall wheatgrass to be given priority in revegetation studies in Turkey. Three pre-germinated seeds of each grass species were planted separately into the soil in the black plastic containers. Seedlings were harvested 2, 4 and 6 months after planting pre-germinated seeds and measured for percentage of seedling emergence, rooting depth, height growth, leaf and tiller development and shoot and root weights. Germination percentage was 97.8% for perennial ryegrass, 64.1% for orchardgrass and 11.6% for tall wheatgrass and perennial ryegrass had the greatest whereas tall wheatgrass had the lowest seedling emergence. Two months old rooting depth was 25.66 cm for perennial ryegrass, 20.56 cm for orchardgrass and 30.10 cm for tall wheatgrass. At the end of the study, perennial ryegrass developed about 104 tillers per plant while they were 21.4 and 36.6 tillers per plant for orchardgrass and tall wheatgrass, respectively. Orchardgrass produced greater shoot and root biomasses than tall wheatgrass and similar to perennial ryegrass. All these meant that perennial ryegrass had a better growth performance than orchardgrass and tall wheatgrass to be used for erosion control. PMID:12974411
Issues of upscaling in space and time with soil erosion models
NASA Astrophysics Data System (ADS)
Brazier, R. E.; Parsons, A. J.; Wainwright, J.; Hutton, C.
Soil erosion - the entrainment, transport and deposition of soil particles - is an important phenomenon to understand; the quantity of soil loss determines the long term on-site sustainability of agricultural production (Pimental et al., 1995), and has potentially important off-site impacts on water quality (Bilotta and Brazier, 2008). The fundamental mechanisms of the soil erosion process have been studied at the laboratory scale, plot scale (Wainwright et al., 2000), the small catchment scale (refs here) and river basin scale through sediment yield and budgeting work. Subsequently, soil erosion models have developed alongside and directly from this empirical work, from data-based models such as the USLE (Wischmeier and Smith, 1978), to æphysics or process-based' models such as EUROSEM (Morgan et al., 1998) and WEPP (Nearing et al., 1989). Model development has helped to structure our understanding of the fundamental factors that control soil erosion process at the plot and field scale. Despite these advances, however, our understanding of and ability to predict erosion and sediment yield at the same plot, field and also larger catchment scales remains poor. Sediment yield has been shown to both increase and decrease as a function of drainage area (de Vente et al., 2006); the lack of a simple relationship demonstrates complex and scale-dependant process domination throughout a catchment, and emphasises our uncertainty and poor conceptual basis for predicting plot to catchment scale erosion rates and sediment yields (Parsons et al., 2006b). Therefore, this paper presents a review of the problems associated with modelling soil erosion across spatial and temporal scales and suggests some potential solutions to address these problems. The transport-distance approach to scaling erosion rates (Wainwright, et al., 2008) is assessed and discussed in light of alternative techniques to predict erosion across spatial and temporal scales. References Bilotta, G.S. and Brazier, R.E., 2008. Understanding the influence of suspended solids on water quality and aquatic biota. Water Research, 42(12): 2849-2861. de Vente, J., Poesen, J., Bazzoffi, P., Van Ropaey, A.V. and Verstraeten, G., 2006. Predicting catchment sediment yield in Mediterranean environments: the importance of sediment sources and connectivity in Italian drainage basins. Earth Surface Processes And Landforms, 31: 1017-1034. Morgan, R.P.C. et al., 1998. The European soil erosion model (EUROSEM): a dynamic approach for predicting sediment transport from fields to small catchments. Earth Surface Processes And Landforms, 23: 527-544. Nearing, M. A., G. R. Foster, L. J. Lane, and S. C. Finkner. 1989. A process-based soil erosion model for USDA Water Erosion Prediction Project technology. Trans. ASAE 32(5): 1587-1593. Parsons, A.J., Brazier, R.E., Wainwright, J. and Powell, D.M., 2006a. Scale relationships in hillslope runoff and erosion. Earth Surface Processes and Landforms, 31(11): 1384-1393. Parsons, A.J., Wainwright, J., Brazier, R.E. and Powell, D.M., 2006b. Is sediment delivery a fallacy? Earth Surface Processes and Landforms, 31(10): 1325-1328. Pimental, D. et al., 1995. Environmental and economic costs of soil erosion and conservation benefits. Science, 267:1117-1122. Wainwright, J., Parsons, A.J. and Abrahams, A.D., 2000. Plot-scale studies of vegetation, overland flow and erosion interactions: case studies from Arizona and New Mexico. Hydrological Processes, 14(16-17): 2921-2943. Wischmeier, W.H. and Smith, D.D., 1978. Predicting rainfall erosion losses - a guide for conservation planning., 537.
Fluvial Erosion Measurements of Streambank Using Photo-Electronic Erosion Pins (peep)
NASA Astrophysics Data System (ADS)
Sutarto, T.; Papanicolaou, T.; Wilson, C. G.; Bertrand, F.
Cohesive streambank erosion is characterized by two main mechanisms, fluvial entrainment of individual particles and bank failure due to gravity (Thorne, 1980). In this study, the relative importance of fluvial erosion (compared to mass failure) was determined in two reaches from different locations of the Clear Creek Watershed (CCW). The main goal of the project was the identification of the key erosion process at each site. Beyond the distinguished flow conditions (hydraulic forces), different stream orders, and land-use, no further attempts were made to identify other key driving agents behind the erosion, such subaerial processes (e.g., seepage, freeze/thaw) acting at the cohesive riverbanks (Lindow et al., 2009). Erosion lengths up to 38 cm were detected. The bank erosion monitoring at high resolution intervals due to the PEEPS allowed for better characterization the fluvial erosion occurring at this site and develop a correspondence between sedigraphs and hydrographs. .Similar statistical methods were used at both sites to support our findings. The moving average identified the dominant trend of the data and the variability of the erosion lengths at the two sites. Further, the use of the Shewhart Charts allowed us to detect the critical erosion events during the period of observation. Finally the overall performance of the PEEPs was evaluated during this study. A correlation analysis was conducted between the direct measurements of traditional methods (e.g., erosion pins, geodetical surveys, measure tape) and the automated data recorded by the PEEP. The maximum error between manual and automated measurements of the exposed length of the PEEPs was less than 27%. The error between the channel survey and the automated PEEP measurements was less than 14%.
Erosion dynamics of a wet granular medium.
Lefebvre, Gautier; Jop, Pierre
Liquid may give strong cohesion properties to a granular medium, and confer a solidlike behavior. We study the erosion of a fixed circular aggregate of wet granular matter subjected to a flow of dry grains inside a half-filled rotating drum. During the rotation, the dry grains flow around the fixed obstacle. We show that its diameter decreases linearly with time for low liquid content, as wet grains are pulled out of the aggregate. This erosion phenomenon is governed by the properties of the liquids. The erosion rate decreases exponentially with the surface tension while it depends on the viscosity to the power -1. We propose a model based on the force fluctuations arising inside the flow, explaining both dependencies: The capillary force acts as a threshold and the viscosity controls the erosion time scale. We also provide experiments using different flowing grains, confirming our model. PMID:24125259
Erosion dynamics of a wet granular medium
Gautier Lefebvre; Pierre Jop
Liquid may give strong cohesion properties to a granular medium, and confer a solid-like behavior. We study the erosion of a fixed circular aggregate of wet granular matter subjected to a flow of dry grains inside a half-filled rotating drum. During the rotation, the dry grains flow around the fixed obstacle. We show that its diameter decreases linearly with time for low liquid content, as wet grains are pulled-out of the aggregate. This erosion phenomenon is governed by the properties of the liquids. The erosion rate decreases exponentially with the surface tension while it depends on the viscosity to the power -1. We propose a model based on the force fluctuations arising inside the flow, explaining both dependencies: the capillary force acts as a threshold and the viscosity controls the erosion time scale. We also provide experiments using different flowing grains confirming our model.
Seepage Erosion Impacts on Edge-of-Field Gully Erosion
Technology Transfer Automated Retrieval System (TEKTRAN)
Studies have found that the dominant source of sediment in streams can be from bank erosion. Subsurface flow contributes directly to bank failure by seepage erosion and soil-pipe erosion and indirectly by the impact of increased soil water pressures on loss of soil shear strength. Seepage erosion in...
A Rangeland Hydrology and Erosion Model for Developing Ecological Site Descriptions
NASA Astrophysics Data System (ADS)
Nearing, M. A.; Hernandez, M.; Armendariz, G.; Barker, S.; Williams, C. J.
Predicting soil erosion is common practice in natural resource management for assessing the effects of management practices and control techniques of soil productivity, sediment delivery and off site water quality. The Rangeland Hydrology and Erosion Model (RHEM) was designed for this purpose. RHEM is an event-based model that estimates runoff, erosion, and sediment delivery rates and volumes at the spatial scale of the hillslope and the temporal scale of as single rainfall event. It represents erosion processes under normal and fire-impacted rangeland conditions. Moreover, it adopts a new splash erosion and thin sheet -flow transport equation developed from rangeland data, and it links the model hydrologic and erosion parameters with rangeland plant community by providing a new system of parameter estimation equations based on 204 plots at 49 rangeland sites distributed across 15 western U.S. states. Testing was done using long-term runoff and erosion data from small semi-aridland catchments. One of our goals with this project is to develop a framework for incorporating key ecohydrologic information/relationships in Ecological Site Descriptions and thereby enhanced utility of Ecological Site Descriptions s for guiding management. These key ecohydrologic relationships govern the ecologic resilience of the various states and community phases on many rangeland ecological sites and are strongly affected by management practices, land use, and disturbances. However, ecohydrologic data and relationships are often missing in Ecological Site Descriptions and resilience-based state-and-transition models. In this study we applied the RHEM model to data from multiple points in several ecological sites in Arizona, New Mexico, and Utah to assess the utility of the model for informing these Ecological Site Descriptions.
Water droplet erosion mechanisms of Ti-6Al-4V
NASA Astrophysics Data System (ADS)
Kamkar Zahmatkesh, Niloofar
Water impingement erosion of materials can be a life-limiting phenomenon for the components in many erosive environments. For example, aircraft body exposed to rain, steam turbine blade, and recently in gas turbine coupled with inlet fogging system. The last is the focus of this study. Inlet fogging system is the most common method used to augment gas turbine output during hot days; high ambient temperature causes strong deterioration of the engine performance. Micro-scaled droplets introduced into the inlet airflow allow the cooling of entering air as well as intercooling the compressor (overspray) and thus optimizes the output power. However, erosion damage of the compressor blades in overspray stage is one of the major concerns associated with the inlet fogging system. The main objective of this research work (CRIAQ MANU419 project) is to understand the erosion induced by water droplets on Titanium alloy to eventually optimize the erosion resistance of the Ti-based compressor blade. Therefore, characterization of the water droplet erosion damage on Ti-6Al-4V receives the major importance. The influence of base material microstructure and impact parameters were considered in erosion evaluation in present study. This work covers the characterization of the erosion damage on Ti-6Al-4V alloy in two parts: - The water droplet erosion damage through a novel experimental approach. The collected data were processed both qualitatively and quantitatively for multi-aspects damage study. - The influence of impact velocity on erosion in an attempt to represent the in-service conditions.
Conventional and anti-erosion fluoride toothpastes: effect on enamel erosion and erosion-abrasion.
Ganss, C; Lussi, A; Grunau, O; Klimek, J; Schlueter, N
New toothpastes with anti-erosion claims are marketed, but little is known about their effectiveness. This study investigates these products in comparison with various conventional NaF toothpastes and tin-containing products with respect to their erosion protection/abrasion prevention properties. In experiment 1, samples were demineralised (10 days, 6 ū 2 min/day; citric acid, pH 2.4), exposed to toothpaste slurries (2 ū 2 min/day) and intermittently stored in a mineral salt solution. In experiment 2, samples were additionally brushed for 15 s during the slurry immersion time. Study products were 8 conventional NaF toothpastes (1,400-1,490 ppm F), 4 formulations with anti-erosion claims (2 F toothpastes: NaF + KNO(3) and NaF + hydroxyapatite; and 2 F-free toothpastes: zinc-carbonate-hydroxyapatite, and chitosan) and 2 Sn-containing products (toothpaste: 3,436 ppm Sn, 1,450 ppm F as SnF(2)/NaF; gel: 970 ppm F, 3,030 ppm Sn as SnF(2)). A mouth rinse (500 ppm F as AmF/NaF, 800 ppm Sn as SnCl(2)) was the positive control. Tissue loss was quantified profilometrically. In experiment 1, most NaF toothpastes and 1 F-free formulation reduced tissue loss significantly (between 19 and 42%); the Sn-containing formulations were the most effective (toothpaste and gel 55 and 78% reduction, respectively). In experiment 2, only 4 NaF toothpastes revealed significant effects compared to the F-free control (reduction between 29 and 37%); the F-free special preparations and the Sn toothpaste had no significant effect. The Sn gel (reduction 75%) revealed the best result. Conventional NaF toothpastes reduced the erosive tissue loss, but had limited efficacy regarding the prevention of brushing abrasion. The special formulations were not superior, or were even less effective. PMID:22156703
NASA Technical Reports Server (NTRS)
Baughman, J. R.; Spies, R.
Study of impact erosion in the operation of turbomachinery is undertaken to predict the results for particular designs. The test program investigates the effects of turbine stator blade shape, rotor blade shape, and variations in test conditions.
Bolleter, Jim Mason
ABSTRACT Galveston Island and Erosion. (May 1985) Jim Mason Bolleter, B. S. , Texas AM University Chairman of Advisory Committee: Dr. A. R. Benton Jr. Mid-term changes in the beach vegetation line on Galveston Island, I as well as the erosional effects... of recent hurri canes and tropical . storms, wer e documented with multi -date aerial photography. While ~ localized accretion has occurred on East Beach due to the shadowing effect of the South Jetty, West beach has fluctuated between erosion Major...
Finite Convergence of a Subgradient Projections Method with Expanding Controls
Censor, Yair, E-mail: email@example.com [University of Haifa, Department of Mathematics (Israel); Chen Wei, E-mail: email@example.com [Massachusetts General Hospital and Harvard Medical School, Department of Radiation Oncology (United States); Pajoohesh, Homeira, E-mail: email@example.com [City University of New York, Department of Mathematics, Medgar Evers College (United States)
We study finite convergence of the modified cyclic subgradient projections (MCSP) algorithm for the convex feasibility problem (CFP) in the Euclidean space. Expanding control sequences allow the indices of the sets of the CFP to re-appear and be used again by the algorithm within windows of iteration indices whose lengths are not constant but may increase without bound. Motivated by another development in finitely convergent sequential algorithms that has a significant real-world application in the field of radiation therapy treatment planning, we show that the MCSP algorithm retains its finite convergence when used with an expanding control that is repetitive and fulfills an additional condition.
NIF Projects Controls and Information Systems Software Quality Assurance Plan
Fishler, B
Quality achievement for the National Ignition Facility (NIF) and the National Ignition Campaign (NIC) is the responsibility of the NIF Projects line organization as described in the NIF and Photon Science Directorate Quality Assurance Plan (NIF QA Plan). This Software Quality Assurance Plan (SQAP) is subordinate to the NIF QA Plan and establishes quality assurance (QA) activities for the software subsystems within Controls and Information Systems (CIS). This SQAP implements an activity level software quality assurance plan for NIF Projects as required by the LLNL Institutional Software Quality Assurance Program (ISQAP). Planned QA activities help achieve, assess, and maintain appropriate quality of software developed and/or acquired for control systems, shot data systems, laser performance modeling systems, business applications, industrial control and safety systems, and information technology systems. The objective of this SQAP is to ensure that appropriate controls are developed and implemented for management planning, work execution, and quality assessment of the CIS organization's software activities. The CIS line organization places special QA emphasis on rigorous configuration control, change management, testing, and issue tracking to help achieve its quality goals.
Technology Transfer Automated Retrieval System (TEKTRAN)
Row-cropping and grazing in riparian areas have altered the natural hydrologic cycle and accelerated stream incision and bank erosion. In incised streams, bank erosion can typically contribute 50 to 90% of the stream's sediment and phosphorus load. In this northeast Iowa project, stream bank erosion...
Controls on decadal erosion rates in Qilian Shan: Re-evaluation and new insights into landscape evolution in north-east Tibet
NASA Astrophysics Data System (ADS)
Yizhou, Wang; Huiping, Zhang; Dewen, Zheng; Wenjun, Zheng; Zhuqi, Zhang; Weitao, Wang; Jingxing, Yu
Available data from the Qilian Shan in north-east Tibet suggested that decadal-scale erosion rates were closely correlated with local topographic gradient, but not with climatic factors. However, a climatic change to more arid condition was proposed to explain the discrepancy between short-term and long-term erosion rates. In order to re-evaluate the topographic, tectonic and climatic influences on erosion, we adopted five parameters (slope, mean local relief, historical cumulative seismic moment, runoff coefficient of variation and fault density) to study 11 drainage basins in north-east Tibet. Our results showed that terrain gradient, rock fracture density and rainstorm intensity had strong influence on erosion rates while 60-year cumulative seismic moments of historical earthquakes showed weaker correlations. There was a spatial variation in the erosional mechanisms across the basin, with detachment-limited dominance around the ridges (slope > 20░) and deposition dominant in the flat areas. The variation may lead to the discrepancy between short-term and long-term erosion rates. In general, our study supports the æbath-tubÆ model for low relief intermountain basins, hence providing new insights into the landscape evolution of the Qilian Shan in northeastern Tibetan Plateau.
Panagos, Panos; Ballabio, Cristiano; Borrelli, Pasquale; Meusburger, Katrin; Klik, Andreas; Rousseva, Svetla; Tadi?, Melita Per?ec; Michaelides, Silas; HrabalĒkovß, Michaela; Olsen, Preben; Aalto, Juha; Lakatos, M¾nika; Rymszewicz, Anna; Dumitrescu, Alexandru; BeguerĒa, Santiago; Alewell, Christine
Rainfall is one the main drivers of soil erosion. The erosive force of rainfall is expressed as rainfall erosivity. Rainfall erosivity considers the rainfall amount and intensity, and is most commonly expressed as the R-factor in the USLE model and its revised version, RUSLE. At national and continental levels, the scarce availability of data obliges soil erosion modellers to estimate this factor based on rainfall data with only low temporal resolution (daily, monthly, annual averages). The purpose of this study is to assess rainfall erosivity in Europe in the form of the RUSLE R-factor, based on the best available datasets. Data have been collected from 1541 precipitation stations in all European Union (EU) Member States and Switzerland, with temporal resolutions of 5 to 60 min. The R-factor values calculated from precipitation data of different temporal resolutions were normalised to R-factor values with temporal resolutions of 30 min using linear regression functions. Precipitation time series ranged from a minimum of 5 years to a maximum of 40 years. The average time series per precipitation station is around 17.1 years, the most datasets including the first decade of the 21st century. Gaussian Process Regression (GPR) has been used to interpolate the R-factor station values to a European rainfall erosivity map at 1 km resolution. The covariates used for the R-factor interpolation were climatic data (total precipitation, seasonal precipitation, precipitation of driest/wettest months, average temperature), elevation and latitude/longitude. The mean R-factor for the EU plus Switzerland is 722 MJ mm ha(-1) h(-1) yr(-1), with the highest values (>1000 MJ mm ha(-1) h(-1) yr(-1)) in the Mediterranean and alpine regions and the lowest (<500 MJ mm ha(-1) h(-1) yr(-1)) in the Nordic countries. The erosivity density (erosivity normalised to annual precipitation amounts) was also the highest in Mediterranean regions which implies high risk for erosive events and floods. PMID:25622150
Greenridge Multi-Pollutant Control Project Preliminary Public Design Report
Daniel P. Connell
The Greenidge Multi-Pollutant Control Project is being conducted as part of the U.S. Department of Energy's Power Plant Improvement Initiative to demonstrate an innovative combination of air pollution control technologies that can cost-effectively reduce emissions of SO{sub 2}, NO{sub x}, Hg, acid gases (SO{sub 3}, HCl, and HF), and particulate matter from smaller coal-fired electrical generating units (EGUs). The multi-pollutant control system includes a hybrid selective non-catalytic reduction (SNCR)/in-duct selective catalytic reduction (SCR) system to reduce NOx emissions by {ge}60%, followed by a Turbosorp{reg_sign} circulating fluidized bed dry scrubber system to reduce emissions of SO{sub 2}, SO{sub 3}, HCl, and HF by {ge}95%. Mercury removal of {ge}90% is also targeted via the co-benefits afforded by the in-duct SCR, dry scrubber, and baghouse and by injection of activated carbon upstream of the scrubber, as required. The technology is particularly well suited, because of its relatively low capital and maintenance costs and small space requirements, to meet the needs of coal-fired units with capacities of 50-300 MWe. There are about 440 such units in the United States that currently are not equipped with SCR, flue gas desulfurization (FGD), or mercury control systems. These smaller units are a valuable part of the nation's energy infrastructure, constituting about 60 GW of installed capacity. However, with the onset of the Clean Air Interstate Rule, Clean Air Mercury Rule, and various state environmental actions requiring deep reductions in emissions of SO{sub 2}, NO{sub x}, and mercury, the continued operation of these units increasingly depends upon the ability to identify viable air pollution control retrofit options for them. The large capital costs and sizable space requirements associated with conventional technologies such as SCR and wet FGD make these technologies unattractive for many smaller units. The Greenidge Project aims to confirm the commercial readiness of an emissions control system that is specifically designed to meet the environmental compliance requirements of these smaller coal-fired EGUs. The multi-pollutant control system is being installed and tested on the AES Greenidge Unit 4 (Boiler 6) by a team including CONSOL Energy Inc. as prime contractor, AES Greenidge LLC as host site owner, and Babcock Power Environmental Inc. as engineering, procurement, and construction contractor. All funding for the project is being provided by the U.S. Department of Energy, through its National Energy Technology Laboratory, and by AES Greenidge. AES Greenidge Unit 4 is a 107 MW{sub e} (net), 1950s vintage, tangentially-fired, reheat unit that is representative of many of the 440 smaller coal-fired units identified above. Following design and construction, the multi-pollutant control system will be demonstrated over an approximately 20-month period while the unit fires 2-4% sulfur eastern U.S. bituminous coal and co-fires up to 10% biomass. This Preliminary Public Design Report is the first in a series of two reports describing the design of the multi-pollutant control facility that is being demonstrated at AES Greenidge. Its purpose is to consolidate for public use all available nonproprietary design information on the Greenidge Multi-Pollutant Control Project. As such, the report includes a discussion of the process concept, design objectives, design considerations, and uncertainties associated with the multi-pollutant control system and also summarizes the design of major process components and balance of plant considerations for the AES Greenidge Unit 4 installation. The Final Public Design Report, the second report in the series, will update this Preliminary Public Design Report to reflect the final, as-built design of the facility and to incorporate data on capital costs and projected operating costs.
Erosion and the rocks of Venus
NASA Technical Reports Server (NTRS)
Sagan, C.
Photographs of the surface of Venus returned by the Venera 9 and 10 spacecraft have revealed the presence of smooth and angular rockline forms. Two mechanisms previously suggested (Sagan, 1975) for erosion of crater ramparts on the surface of Venus might also explain the erosion of rocks. Chemical weathering by the hydrochloric, hydrofluoric, and sulfuric acids present in the atmosphere of Venus may have been sufficient to erode angular projections of silicous rocks. Alternatively, the contours of rocks containing such low-melting materials as NaOH, KOH, HgS and KNO2 may have softened as the result of exposure to the high surface temperatures of the planet.
Towards a national-scale understanding of soil erosion in the UK: Building a national soil erosion database
NASA Astrophysics Data System (ADS)
Benaud, Pia; Carvalho, Jason; Truckell, Ian; Rickson, Jane; Anderson, Karen; Quine, Timothy; Brazier, Richard
The United Kingdom has a rich dataset of soil erosion observations, which have been collected using a wide range of methodologies, across various spatial and temporal scales. Yet, whilst observations of soil erosion have been carried out along-side agricultural development and intensification, understanding whether or not the UK has a soil erosion problem remains a question to be answered. Furthermore, although good reviews of existing soil erosion rates exist, there isn't a single resource that brings all of this work together. The following work seeks remedy this situation through collating all available, UK-based, soil erosion datasets into a spatially explicit database, describing soil erosion at the national scale. Soil erosion occurs through a complex series of processes, consequently, capturing the full extent of soil erosion requires utilising a suite of techniques across varying spatial and temporal scales, and a wide range of soil types and land management practices. However, preliminary analysis of the geodatabase has highlighted the ad hoc and biased nature of previous soil erosion studies. Exploring the spatial distribution of the datasets has identified a general trend towards conducting erosion studies at locations known to erode. Furthermore, many of the studies use a single research method and are thus unable to capture all erosion processes or pathways. For example, whilst volumetric surveys can quantify soil loss via large rills and gullies, such methods cannot quantify the less-visible, diffuse erosion processes due to sheetwash, wind or tillage (for example). Collating and visualising all UK-based soil erosion datasets has been a useful exercise, however, it has highlighted many shortfalls within existing soil erosion research. The database, therefore, cannot be used to make an unbiased assessment of UK erosion rates. As such, there is a strong argument for a replicable and robust national soil erosion monitoring program to be carried out along-side the proposed sustainable intensification of agriculture. Furthermore, due to the variability in methods used, scales of understanding and units of the data that has been collected, the database justifies further work to develop an understanding of the compatibility of erosion data that were collected using different techniques at different scales of interest. The collation of soil erosion data into the database is an on-going, open-access project and resource; consequently, any researchers wishing to contribute are encouraged to get in touch, especially if they hold existing datasets that may be added to the geodatabase.
Removing erosion control projects increases bank swallow ( Riparia riparia) population viability modeled along the Sacramento River, California, USA
Evan H. Girvetz
Spatially-explicit population viability analysis (PVA) is a powerful method for modeling the extinction risk of populations that show variation over space and time. It is especially effective for comparing relative effect of different management scenarios on population dynamics. Here, I present a habitat patch-based PVA for a population of the California state-listed threatened bank swallow (Riparia riparia) nesting along the
Forests and Soil Erosion across Europe
NASA Astrophysics Data System (ADS)
Bathurst, J. C.
Land use and climate change threaten the ability of Europe's forests to provide a vital service in limiting soil erosion, e.g. from forest fires and landslides. However, our ability to define the threat and to propose mitigation measures suffers from two deficiencies concerning the forest/erosion interface: 1) While there have been a considerable number of field studies of the relationship between forest cover and erosion in different parts of Europe, the data sets are scattered among research groups and a range of literature outlets. There is no comprehensive overview of the forest/erosion interface at the European scale, essential for considering regional variations and investigating the effects of future changes in land use and climate. 2) Compared with forest/water studies, we have a poorer quantitative appreciation of forest/erosion interactions. In the forest/water area it is possible to make quantitative statements such as that a 20% change in forest cover across a river catchment is needed for the effect on annual water yield to be measurable or that a forested catchment in upland UK has an annual water yield around 15% lower than an otherwise comparable grassland catchment. Comparable statements are not yet possible for forest/erosion interactions and there are uncertainties in the mathematical representation of forest/erosion interactions which limit our ability to make predictions, for example of the impact of forest loss in a given area. This presentation therefore considers the next step in improving our predictive capability. It proposes the integration of existing research and data to construct the "big picture" across Europe, i.e. erosion rates and sediment yields associated with forest cover and its loss in a range of erosion regimes (e.g. post-forest fire erosion or post-logging landslides). This would provide a basis for generalizations at the European scale. However, such an overview would not form a predictive capability. Therefore it is also necessary to identify a range of predictive methods, from empirical guidelines to computer models, which can be recommended for applications such as extrapolating from the local to the regional scale and for planning mitigation strategies. Such developments could help improve efficiency in the integrated management of forest, soil and water resources, benefit local engineering projects ranging from hazard mitigation plans to road culvert design, contribute to the implementation of the EU Water Framework Development, form a more objective basis for cost/benefit analysis of proposed management actions and help in putting a value on forest services.
Material control and surveillance for high frequency access vaults project
Longmire, V. L. (Victoria L.); Stevens, R. S. (Rebecca S.); Martinez, B. J. (Benny J.); Butler, G. W. (Gilbert W.); Huang, J. Y. (John Y.); Pickett, C. (Chris); Younkin, J. (James); Dunnigan, Janelle; Gaby, Jane; Lawson, R. (Roger)
The 'Material Control and Surveillance for High Frequency Access Vaults' project sponsored by United States Department of Energy's Office of Security Policy, Policy Integration and Technical Support Program (SO-20.3) focuses on enhancing nuclear materials control and surveillance in vaults that are frequently accessed. The focus of this effort is to improve materials control and accountability (MC&A) while decreasing the operational impact of these activities. Los Alamos and Y-12 have developed a testbed at the Los Alamos National Laboratory for evaluating and demonstrating integrated technologies for use in enhancing materials control and accountability in active nuclear material storage vaults. An update will be provided on the new systems demonstrated in the test-bed including a 'confirmatory cart' for expediting the performance of inventory and radio-frequency actuated video that demonstrates the concept of automated data entry for materials moving between MBA's. The United States Department of Energy's Office of Security Policy, Policy Integration and Technical Support Program (SO-20.3) has sponsored a project where nuclear material inventory, control and surveillance systems are evaluated, developed, and demonstrated in an effort to provide technologies that reduce risk, increase material assurance, and provide cost-efficient alternatives to manpower-intensive physical inventory and surveillance approaches for working (high-frequency-access) vaults. This Fiscal Year has been largely focused on evaluating and developing components of two sub-systems that could be used either separately in nuclear material vaults or as part of a larger integrated system for nuclear materials accountability, control and surveillance.
Bank erosion events and processes in the Upper Severn basin
NASA Astrophysics Data System (ADS)
Lawler, D. M.; Couperthwaite, J.; Bull, L. J.; Harris, N. M.
This paper examines river bank retreat rates, individual erosion events, and the processes that drive them in the Upper Severn basin, mid-Wales, UK. Traditional erosion pin networks were used to deliver information on patterns of downstream change in erosion rates. In addition, the novel automatic Photo-Electronic Erosion Pin (PEEP) monitoring system was deployed to generate near-continuous data on the temporal distribution of bank erosion and accretion: this allowed focus on the magnitude and timing of individual erosional and depositional events in relation to specific flow episodes. Erosion dynamics data from throughout the Upper Severn basin are combined with detailed information on bank material properties and spatial change in channel hydraulics derived from direct field survey, to assess the relationships between flow properties and bank erosion rates. Results show that bank erosion rates generally increase downstream, but relate more strongly to discharge than to reach-mean shear stress, which peaks near the basin head. Downstream changes in erosion mechanisms and boundary materials, across the upland/lowland transition (especially the degree of development of composite bank material profiles), are especially significant. Examples of sequences of bank erosion events show how the PEEP system can (a) quantify the impact of individual, rather than aggregated, forcing events, (b) reveal the full complexity of bank response to given driving agents, including delayed erosion events, and (c) establish hypotheses of process-control in bank erosion systems. These findings have important implications for the way in which bank erosion problems are researched and managed. The complex responses demonstrated have special significance for the way in which bank processes and channel-margin sediment injections should be handled in river dynamics models.
The Large Synoptic Survey Telescope project management control system
NASA Astrophysics Data System (ADS)
Kantor, Jeffrey P.
The Large Synoptic Survey Telescope (LSST) program is jointly funded by the NSF, the DOE, and private institutions and donors. From an NSF funding standpoint, the LSST is a Major Research Equipment and Facilities (MREFC) project. The NSF funding process requires proposals and D&D reviews to include activity-based budgets and schedules; documented basis of estimates; risk-based contingency analysis; cost escalation and categorization. "Out-of-the box," the commercial tool Primavera P6 contains approximately 90% of the planning and estimating capability needed to satisfy R&D phase requirements, and it is customizable/configurable for remainder with relatively little effort. We describe the customization/configuration and use of Primavera for the LSST Project Management Control System (PMCS), assess our experience to date, and describe future directions. Examples in this paper are drawn from the LSST Data Management System (DMS), which is one of three main subsystems of the LSST and is funded by the NSF. By astronomy standards the LSST DMS is a large data management project, processing and archiving over 70 petabyes of image data, producing over 20 petabytes of catalogs annually, and generating 2 million transient alerts per night. Over the 6-year construction and commissioning phase, the DM project is estimated to require 600,000 hours of engineering effort. In total, the DMS cost is approximately 60% hardware/system software and 40% labor.
The cost control of communication construction projects: Case study of Zhejiang Post and Telecommunication Construction Corporation
Zheng Ye; Da-jia Mao
With the increasing competition of communication industry, how to improve the economic efficiency of construction project has been a very urgent task for the communication construction enterprises. This article first posts the importance of cost control in communication construction project. Then further applications are integrated in the cost control of construction projects to Taizhou project department in the sample enterprise,
Research on target cost control of construction project based on goal programming
H. Zhao; G. He
Target cost control of construction projects is an important part of project management, and it plays a crucial role on the benefit of construction projects. In this paper, the issue about target cost control on the early stage of construction projects has been explored further. Firstly, this paper elaborates on determination principles and measurement methods of target cost of construction
Cost and time control of construction projects: inhibiting factors and mitigating measures in practice
Yakubu Adisa Olawale; Ming Sun
Despite the availability of various control techniques and project control software many construction projects still do not achieve their cost and time objectives. Research in this area so far has mainly been devoted to identifying causes of cost and time overruns. There is limited research geared towards studying factors inhibiting the ability of practitioners to effectively control their projects. To
Human Connectome Project Informatics: Quality control, database services, and data visualization
įž ┼ ę┘ū ų įž Human Connectome Project Informatics: Quality control, database services, and data Project Informat- ics: Quality control, database services, and data visualization, NeuroImage (2013), doi ACCEPTED MANUSCRIPT 1 Human Connectome Project Informatics: quality control, database services, and data
A wood-strand material for wind erosion control: effects on total sediment loss, PM10 vertical flux, and PM10 loss
Technology Transfer Automated Retrieval System (TEKTRAN)
Wind erosion is a widespread problem in much of the western United States due to arid conditions and persistent winds. Fugitive dust emitted from eroding land poses a risk to both environmental quality and human health. The Clean Air Act, established in 1971, was revised in 1987 to include ambient a...
Highly erodible terrain in agriculture land against chipped pruned branches. Or how to stop the soil erosion with low investment
NASA Astrophysics Data System (ADS)
CerdÓ, A.
The session on "Soil erosion and sediment control with vegetation and bioengineering on severely eroded terrain" pays special attention to the severe soil erosion suffered on steep slopes and erodible parent materials and soils. Within the last 20 years, in the Mediterranean lands, the citrus orchards were reallocated on steep slopes due to the urban development and better climatic and management conditions of the new plantations. The lack of vegetation cover on the new slope plantations of citrus resulted in high erosion rates. Those non-sustainable soil losses were measured by means of rainfall simulation experiments, Gerlach collectors, geomorphological transect and topographical measurements. The October 2007 and October 2008 rainy periods resulted in sheet, rill and gully erosion. Some recently planted orchards (2005) had the first pruning season in 2008. The pruned chipped branches reduced the soil losses to 50 % of the expected, although the litter (pruned branches) covered 4.67 % of the soil. This is why a research was developed by means of simulated rainfall experiments to determine the vegetation cover (litter, mainly leaves) to protect the soil to reach a sustainable erosion rate. Rainfall simulation experiments at 43 mm h-1 where performed on 1 m2 plots covered with 0, 3, 7, 15, 30, 45, 60, 80 and 100 % litter cover (pruned chipped branches) to determine the sustainable litter cover to avoid the soil losses. The results show that more that 45 % litter cover almost reduces the soil losses to negligible rates. The results confirm that 4 % of vegetation cover reduces the soil losses to 50 %. Key words: Agriculture land, erodible terrain, land management, citrus, erosion, Spain, Valencia, herbicides. Acknowledgements, We thanks the financial support of the Ministerio de Ciencia e Innovaci¾n by means of the project CGL2008-02879/BTE, "PERDIDA DE SUELO EN NUEVAS EXPLOTACIONES CITRICOLAS EN PENDIENTE. ESTRATEGIAS PARA EL CONTROL DE LA EROSION HIDRICA"
NASA Technical Reports Server (NTRS)
2005-01-0130 April 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows wind-eroded sedimentary rocks in Tithonium Chasma, one of the troughs of the Valles Marineris system. The winds responsible for the majority of the erosion blew from the northeast (upper right), creating yardangs (wind erosion ridges) with their tapered ends pointing downwind. Location near: 4.6oS, 88.3oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Winter
NSDL National Science Digital Library
Bill Dupre
Students are presented with a real-life problem of flooding and erosion in the town of Simonton. They must use historical dischage data to determine the future risk of flooding. They must also use historical map data to asses the risk of future losses due to erosion. Using these data, they must dertermine the feasibility of levee systems proposed by the Corp of Engineers. Lastly, they must discuss their assumption and possible sources of error. Has minimal/no quantitative component Uses geophysics to solve problems in other fields
Effects of topsoiling on rates of erosion and erosion processes in coal mine spoil banks in Utrillas, Teruel, Spain
Josķ M. Nicolau
Runoff production and soil erosion, produced by energetic Mediterranean storms, are amongst the first environmental impacts of opencast mining activity and amongst the main limiting factors in achieving self-sustaining reclaimed landscapes in Teruel. This paper aims to understand the geomorphological response of topsoiled and overburden-covered banks. This is considered essential in improving soil management and designing accurate erosion control plans.
Erosion modelling towards, and sediment transport modelling in unnavigable watercourses in Flanders, Belgium
NASA Astrophysics Data System (ADS)
Ferket, B.; Van De Broek, M.; Van Hoestenberghe, T.; Degerickx, J.; De Sutter, R.; Govers, G.; Dezillie, N.; Deproost, P.
Antea Group and KULeuven were awarded a project in Flanders to identify the regions exporting high sediment loads to unnavigable watercourses and the sedimentation zones within them. Two types of models are applied: hydrological sediment export models (SEM) and hydraulic sediment transport models (STM). The influence of erosion control measures on sediment export as well as river engineering measures needs to be taken into account. A concept will be developed to connect the SEM and STM, enabling the sediment to be routed from upstream to the sedimentation zones. Results of the study will be used by the Flemish government to plan erosion control measures, estimate future sedimentation volumes, steer sedimentation and optimize river engineering and dredging works. Finally, model results could also be used to obtain better insights to the re-suspension risks of contaminated sediment in watercourses.
Assessment of Rainfall, Erosivity, Runoff and Erosion in the Area
Richner, Heinz
Assessment of Rainfall, Erosivity, Runoff and Erosion in the Area North and West of Mount Kenya of the road is private land and does hardly suffer of soil loss and land degradation whilst the other side of the road is over grazed public Maasai land, susceptible to erosion. 1 Centre for Development
Erosive Potential of Oral Care Products
A. Lussi; E. Hellwig
Seven oral care products and orange juice as a positive control were tested for the erosive potential by immersing each enamel specimen (10 per group) into solutions of the various products for 10 and 20 min. Before and after the experiment Knoop surface hardness (SMH) was measured. The enamel microstructure before and after immersion was assessed by scanning electron microscopy
Influence of human saliva on the development of artificial erosions.
Hellwig, E; Lussi, A; Goetz, F
It was hypothesized that saliva from patients with erosion exhibits lower protective efficacy compared to saliva from patients without erosion, based on in vitro enamel softening studies. A total of 645 enamel specimens were distributed among seven experimental groups. Saliva was gathered from each of 10 volunteers without clinical signs of dental erosion and from 10 patients exhibiting severe erosive defects. Aliquots of 50 ml of saliva from each patient were mixed with sour drops or citric acid, respectively. Pooled saliva, sour drops and citric acid mixed with water served as controls. The enamel specimens were soaked in the respective mixture for 5 min and were subsequently incubated in pure saliva for 2 min. This cycle was repeated three times, then the specimens were kept in 100 ml of saliva for 8 h. Surface microhardness was evaluated at the beginning of the experiment and after each cycle. During the experiments, microhardness decreased significantly in all groups except for the pure saliva group. For sour drops and citric acid mixed with saliva from patients without erosion, the final microhardness was higher compared to the mixture of the two erosive compounds with saliva from patients with erosion. The storage of saliva for 8 h resulted in a certain amount of rehardening, with the highest level of rehardening being observed in the group that was least demineralized (sour drops plus saliva from patients without erosion). It is concluded that salivary components play a crucial role in the development of dental erosion. PMID:23838437
IT project management control and the Control Objectives for IT and related Technology (CobiT) framework
Edward W. N. Bernroider; Milen Ivanov
Motivated by scarce academic consideration of project management control frameworks, this article explores usage, value and structure of frameworks with a focus on the popular Control Objectives for IT and related Technology (CobiT) construct. We attempt to add to an empirically validated structure of internal control over IT project management by including CobiT's views on the intended domain of content.
Interdigital erosions - tinea pedis?
Orgaz-Molina, Jacinto; Orgaz-Molina, Maria Carmen; Cutugno, Marilena; Arias-Santiago, Salvador
Interdigital erosions are frequently due to tinea pedis. However, other infectious conditions, such as candidiasis, erythrasma or bacterial infections, can generate lesions that cannot be differentiated at the clinical level. Microbiological tests are therefore necessary. This clinical case shows a man with interdigital lesions of 10 months of evolution that are not responding to antifungal treatment. PMID:23210102
Bioengineering applied to erosion and stability control in the North Apennines (Emilia-Romagna Region, Italy): a check about critical aspects of the works.
NASA Astrophysics Data System (ADS)
Selli, Lavinia; Cavazza, Claudio; Pavanelli, Donatella
Because of its geological structure, in the Emilia-Romagna Region over 32,000 landslides have been identified. Several works have been made in order to control mass movement's dynamics and to secure of Reno and Lamone Mountain Basin Rivers, the road network and near by villages and towns. Most of the control works dealt with bioengineering practices: palisades piles, geotextiles, seedings, surface flow control works, dikes within main drainage ditches. In order to check about critical aspects related to the use of these techniques in the Apennines, a survey in this basins was designed with specific interest in the several kinds of works realised, in which plant species were mostly used and in the factors that affected the success or failure of the works. Territory encompasses steep slopes covered with woods to low reliefs covered with grasslands. It is characterized by prevailing clays, inducing instability, and arenaceous lithology with impermeable soils; drainage density is quite high and hillsides suffer extensive and severe erosion and slope stability problems. Chestnut woods mainly represent land use at higher altitudes, while coppice, pastures and crops are present on milder hillsides. The remaining part of the basin is covered by vineyards, orchards, ponds and urban areas, which are basically located in the valley floor. Precipitation events mainly consist of rainfall ranging between 950-1015 mm per year; few snowfalls occur during winter and a long dry season lasts from June until September. We have analyzed 187 works designed mainly for the consolidation of slope instabilities through a widespread enhancement of the vegetation cover. The surveyed works are classified as a function of their building features: it can be seen that cribwalls and palisades are by far the most common types, being the 24% and the 34% respectively of the works. As far as the most adopted plant species, they were silver willow (Salix alba), Spanish Broom (Spartium Junceum) and purple willow (Salix purpurea). Only the 25% of the interventions was accomplished by the use of secondary plant species, as tamarisk (Tamarix spp.,) blackthorn (Prunus spinosa) , whitethorn (Crataegus spp.), sea-buckthorn (Hipphopae rhamnoides), wild pear (Pyrus pyraster), cottonwood (Populus nigra), eglantine (Rosa spp.), goat-willow (Salix caprea) and cornel (Cornus sanguinea). Better results were achieved with Spanish Broom, a very rural plant that can effectively colonise even poor soils like badlands; as a matter of fact, more than the 75% of the interventions had positive outcomes The efficacy of the consolidation work by the presence of living structures point out an increase of the stability of those interventions older than 4 years, with taking root species present from 54% to 78%. So far, the construction and the reliability of the works have been monitored, in order to capture critical aspects for the success of works and to build a geo-referenced data base of the existing works and their status.
The Role of Preferential Flow Through Soil-Pipes on Ephemeral Gully Erosion
Technology Transfer Automated Retrieval System (TEKTRAN)
Estimates by the USDA for 17 States suggest that ephemeral gully erosion ranges from 18 to 73% of the total erosion with a median of 35%. Concentrated flow is generally considered the controlling process and subsurface flow is often overlooked. Pipe-erosion may occur with no visible evidence until p...
An open trial of topical tacrolimus for erosive oral lichen planus
Lynne Morrison; F. James Kratochvil; Annalisa Gorman
Erosive oral lichen planus is a chronic, painful disease that is frequently refractory to treatment. We describe 6 patients with erosive oral lichen planus, not responsive to topical steroids, who showed substantial improvement with the use of topical tacrolimus ointment 0.1%. This medication was well tolerated and appears to be effective in controlling erosive oral lichen planus. (J Am Acad
The Role of Vegetation for Reducing Wind Erosion on Military Lands
Technology Transfer Automated Retrieval System (TEKTRAN)
It is well known that vegetation (kind, amount, position) reduces wind erosion. Control and prediction of wind erosion requires knowledge of the effectiveness of surface vegetation. Knowing the role of vegetation in reducing wind erosion enhances effective management of military lands. The purpos...
A study on the erosion of Niigata Beach from ERTS-A imagery
NASA Technical Reports Server (NTRS)
Maruyasu, T.
Coastal erosion of Niigata Beach, Japan as a result of construction works is discussed. The application of ERTS-1 imagery for defining and monitoring the extent of the erosion is described. The contribution of ERTS-1 data to studies leading to effective erosion control methods are reported.
Overview of the management submodel in the Wind Erosion Prediction System
Technology Transfer Automated Retrieval System (TEKTRAN)
The Wind Erosion Prediction System (WEPS) is a process-based, daily time-step, computer model that predicts soil erosion via simulation of the physical processes controlling wind erosion. WEPS is comprised of several individual modules (submodels) that reflect different sets of physical processes, ...
Riebe et al., p. 1 Appendix 1. Cosmogenic Nuclide Methods and Erosion Rate Data
Kirchner, James W.
Riebe et al., p. 1 Appendix 1. Cosmogenic Nuclide Methods and Erosion Rate Data (Supplemental information for "Minimal climatic control on erosion rates in the Sierra Nevada, California") Clifford S-catchment erosion rates, (2) the cosmogenic nuclide production rates that we used, (3) our cosmogenic nuclide
Discussion of internal erosion modeling
Technology Transfer Automated Retrieval System (TEKTRAN)
Internal erosion is one common mode of dam failure. Internal erosion occurs when water flows through a cavity, crack, and/or other continuous opening within the embankment, detaching material. The detachment of material (erosion) results in expansion of the continuous flow path, increased discharg...
78 FR 64909 - Southwestern Region: Invasive Plant Control Project, Carson and Santa Fe National Forests, New...
Federal Register 2010, 2011, 2012, 2013, 2014
...EIS) for controlling invasive plants in the Carson...Management Indicator Species population trend for...identified in the 2005 Invasive Plant Control Project...herbicides to control invasive species, remains the...
Cavitation erosion of cobalt based STELLITE alloys, cemented carbides and surface treated low alloy steels
C. J. Heathcock; A. Ball; B PROTHEROE
Results are given for erosion-resistance tests involving several STELLITE alloys, cemented carbides and surface-treated alloy steels. It is shown that the cobalt-rich, solid-solution phase of the STELLITE alloys is the basis of their erosion resistance, while the erosion of cemented carbides is predominantly controlled by the binder phase. It is also found that nickel-based tungsten carbides are more erosion-resistant than
Analysis/control of in-bed tube erosion phenomena in the fluidized bed combustion (FBC) system. Technical progress report No. 12
Lee, S.W.
This technical report summarizes the research work performed and progress achieved during the period of July 1, 1995 to October 30, 1995. The characteristics of resistant coatings were determined and related to metal wastage of in-bed tubes in FBC under various laboratory test conditions, The tests were conducted at high impact velocity, 30 m/s, and short exposure time (4 hours) to minimize oxidation of surrounding surface specimens. No oxidation layer founded on the worn surfaces of AISI 1018 carbon steel, The eroded surfaces and cross sections of coatings tested at high velocity were investigated, The surfaces of coating specimens were eroded through a combined mechanism of brittle and ductile modes, These mechanical properties of materials are strongly dependent on the composition and microstate of materials, rather than to their hardness, For high velocity testing, all of the coatings exhibited {open_quotes}brittle behavior{close_quotes}, i.e., the erosion rate at shallow angles was higher than at steep angles and maximum erosion rate at impact angle of 90{degrees}. Tests will be continued and compared with erosion test results for different thermal sprayed coatings.
Toward a more holistic perspective of soil erosion: Why aeolian research needs to explicitly consider fluvial processes and interactions
NASA Astrophysics Data System (ADS)
Field, Jason P.; Breshears, David D.; Whicker, Jeffrey J.
Soil erosion is driven by not only aeolian but also fluvial transport processes, yet these two types of processes are usually studied independently, thereby precluding effective assessment of overall erosion, potential interactions between the two drivers, and their relative sensitivities to projected changes in climate and land use. Here we provide a perspective that aeolian and fluvial transport processes need to be considered in concert relative to total erosion and to potential interactions, that relative dominance and sensitivity to disturbance vary with mean annual precipitation, and that there are important scale-dependencies associated with aeolian-fluvial interactions. We build on previous literature to present relevant conceptual syntheses highlighting these issues. We then highlight relative investments that have been made in soil erosion and sediment control by comparing the amount of resources allocated to aeolian and fluvial research using readily available metrics. Literature searches suggest that aeolian transport may be somewhat understudied relative to fluvial transport and, most importantly, that only a relatively small number of studies explicitly consider both aeolian and fluvial transport processes. Numerous environmental issues associated with intensification of land use and climate change impacts depend on not only overall erosion rates but also on differences and interactions between aeolian and fluvial processes. Therefore, a more holistic viewpoint of erosional processes that explicitly considers both aeolian and fluvial processes and their interactions is needed to optimize management and deployment of resources to address imminent changes in land use and climate.
Integrated Project Scheduling and Staff Assignment with Controllable Processing Times
Framinan, Jose M.
This paper addresses a decision problem related to simultaneously scheduling the tasks in a project and assigning the staff to these tasks, taking into account that a task can be performed only by employees with certain skills, and that the length of each task depends on the number of employees assigned. This type of problems usually appears in service companies, where both tasks scheduling and staff assignment are closely related. An integer programming model for the problem is proposed, together with some extensions to cope with different situations. Additionally, the advantages of the controllable processing times approach are compared with the fixed processing times. Due to the complexity of the integrated model, a simple GRASP algorithm is implemented in order to obtain good, approximate solutions in short computation times. PMID:24895672
Integrated project scheduling and staff assignment with controllable processing times.
Fernandez-Viagas, Victor; Framinan, Jose M
This paper addresses a decision problem related to simultaneously scheduling the tasks in a project and assigning the staff to these tasks, taking into account that a task can be performed only by employees with certain skills, and that the length of each task depends on the number of employees assigned. This type of problems usually appears in service companies, where both tasks scheduling and staff assignment are closely related. An integer programming model for the problem is proposed, together with some extensions to cope with different situations. Additionally, the advantages of the controllable processing times approach are compared with the fixed processing times. Due to the complexity of the integrated model, a simple GRASP algorithm is implemented in order to obtain good, approximate solutions in short computation times. PMID:24895672
Soil erosion and agricultural sustainability
Montgomery, David R.
Data drawn from a global compilation of studies quantitatively confirm the long-articulated contention that erosion rates from conventionally plowed agricultural fields average 1¢2 orders of magnitude greater than rates of soil production, erosion under native vegetation, and long-term geological erosion. The general equivalence of the latter indicates that, considered globally, hillslope soil production and erosion evolve to balance geologic and climate forcing, whereas conventional plow-based agriculture increases erosion rates enough to prove unsustainable. In contrast to how net soil erosion rates in conventionally plowed fields (?1 mm/yr) can erode through a typical hillslope soil profile over time scales comparable to the longevity of major civilizations, no-till agriculture produces erosion rates much closer to soil production rates and therefore could provide a foundation for sustainable agriculture. PMID:17686990
Soil erosion in Iran: Issues and solutions
NASA Astrophysics Data System (ADS)
Hamidreza Sadeghi, Seyed; CerdÓ, Artemi
Iran currently faces many soil erosion-related problems (see citations below). These issues are resulted from some inherent characteristic and anthropogenic triggering forces. Nowadays, the latter plays more important rule to accelerate the erosion with further emphasis on soil erosion-prone arid and semi arid regions of the country. This contribution attempts to identify and describe the existing main reasons behind accelerated soil erosion in Iran. Appropriate solutions viz. structural and non-structural approaches will be then advised to combat or minimise the problems. Iran can be used as a pilot research site to understand the soil erosion processes in semiarid, arid and mountainous terrain and our research will review the scientific literature and will give an insight of the soil erosion rates in the main factors of the soil erosion in Iran. Key words: Anthropogenic Erosion, Land Degradation; Sediment Management; Sediment Problems Acknowledgements The research projects GL2008-02879/BTE, LEDDRA 243857 and PREVENTING AND REMEDIATING DEGRADATION OF SOILS IN EUROPE THROUGH LAND CARE (RECARE)FP7-ENV-2013- supported this research. References Aghili Nategh, N., Hemmat, A., & Sadeghi, M. (2014). Assessing confined and semi-confined compression curves of highly calcareous remolded soil amended with farmyard manure. Journal of Terramechanics, 53, 75-82. Arekhi, S., Bolourani, A. D., Shabani, A., Fathizad, H., Ahamdy-Asbchin, S. 2012. Mapping Soil Erosion and Sediment Yield Susceptibility using RUSLE, Remote Sensing and GIS (Case study: Cham Gardalan Watershed, Iran). Advances in Environmental Biology, 6(1), 109-124. Arekhi, S., Shabani, A., Rostamizad, G. 2012. Application of the modified universal soil loss equation (MUSLE) in prediction of sediment yield (Case study: Kengir Watershed, Iran). Arabian Journal of Geosciences, 5(6), 1259-1267.Sadeghi, S. H., Moosavi, V., Karami, A., Behnia, N. 2012. Soil erosion assessment and prioritization of affecting factors at plot scale using the Taguchi method. Journal of Hydrology, 448, 174-180. Asadi, H., Moussavi, A., Ghadiri, H., Rose, C. W. 2011. Flow-driven soil erosion processes and the size selectivity of sediment. Journal of Hydrology, 406(1), 73-81. Asadi, H., Raeisvandi, A., Rabiei, B., Ghadiri, H. 2012. Effect of land use and topography on soil properties and agronomic productivity on calcareous soils of a semiarid region, Iran. Land Degradation & Development, 23(5), 496-504. Ayoubi, S., Ahmadi, M., Abdi, M. R., Abbaszadeh Afshar, F. 2012. Relationships of< sup> 137 Cs inventory with magnetic measures of calcareous soils of hilly region in Iran. Journal of environmental radioactivity, 112, 45-51. Ayoubi, S., Mokhtari Karchegani, P., Mosaddeghi, M. R., Honarjoo, N. 2012. Soil aggregation and organic carbon as affected by topography and land use change in western Iran. Soil and Tillage Research, 121, 18-26. Emadodin, I., Bork, H. R. 2012. Degradation of soils as a result of long-term human-induced transformation of the environment in Iran: an overview. Journal of Land Use Science, 7(2), 203-219. Emadodin, I., Narita, D., Bork, H. R. 2012. Soil degradation and agricultural sustainability: an overview from Iran. Environment, Development and Sustainability, 14(5), 611-625. Haddadchi, A., Nosrati, K., Ahmadi, F. 2014. Differences between the source contribution of bed material and suspended sediments in a mountainous agricultural catchment of western Iran. CATENA, 116, 105-113. Heshmati, M., Arifin, A., Shamshuddin, J., Majid, N. M. 2012. Predicting N, P, K and organic carbon depletion in soils using MPSIAC model at the Merek catchment, Iran. Geoderma, 175, 64-77. Jafari, R., Bakhshandehmehr, L. 2013. Quantitative mapping and assessment of environmentally sensitive areas to desertification in central Iran. Land Degradation & Development.DOI: 10.1002/ldr.2227 Kavian, A., Azmoodeh, A., Solaimani, K. 2014. Deforestation effects on soil properties, runoff and erosion in northern Iran. Arabian Journal of Geosciences, 7(5), 1941-1950. Khaledi Darvishan, A., Sadeghi,
Seismicity, seismology and erosion
NASA Astrophysics Data System (ADS)
Hovius, Niels; Meunier, Patrick; Burtin, Arnaud; Marc, Odin
At the interface of geomorphology and seismology, patterns of erosion can be used to constrain seismic processes, and seismological instruments to determine geomorphic activity. For example, earthquakes trigger mass wasting in proportion to peak ground velocity or acceleration, modulated by local geologic and topographic conditions. This geomorphic response determines the mass balance and net topographic effect of earthquakes. It can also be used to obtain information about the distribution of seismic slip where instrumental observations are not available. Equally, seismometers can register the signals of geomorphic processes, revealing their location, type and magnitude. The high temporal resolution of such records can help determine the exact meteorological conditions that gave rise to erosion events, and the interactions between individual surface processes during such events. We will illustrate this synergy of disciplines with examples from active mountain belts around the world, including Taiwan, Japan, Papua New Guinea and the Alps.
Landslides, earthquakes, and erosion
NASA Astrophysics Data System (ADS)
Malamud, Bruce D.; Turcotte, Donald L.; Guzzetti, Fausto; Reichenbach, Paola
This paper relates landslide inventories to erosion rates and provides quantitative estimates of the landslide hazard associated with earthquakes. We do this by utilizing a three-parameter inverse-gamma distribution, which fits the frequency-area statistics of three substantially 'complete' landslide-event inventories. A consequence of this general distribution is that a landslide-event magnitude mL=log NLT can be introduced, where NLT is the total number of landslides associated with the landslide event. Using this general distribution, landslide-event magnitudes mL can be obtained from incomplete landslide inventories, and the total area and volume of associated landslides, as well as the area and volume of the maximum landslides, can be directly related to the landslide-event magnitude. Using estimated recurrence intervals for three landslide events and the time span for two historical inventories, we estimate regional erosion rates associated with landslides as typically 0.1-2.5 mm year -1. We next give an empirical correlation between the earthquake magnitude, associated landslide-event magnitude, and the total volume of associated landslides. Using these correlations, we estimate that the minimum earthquake magnitudes that will generate landslides is M=4.3▒0.4. Finally, using Gutenberg-Richter frequency-magnitude statistics for regional seismicity, we relate the intensity of seismicity in an area and the magnitude of the largest regional earthquakes to erosion rates. We find that typical seismically induced erosion rates in active subduction zones are 0.2-7 mm year -1 and adjacent to plate boundary strike-slip fault zones are 0.01-0.7 mm year -1.
Rainfall kinetic energy controlling erosion processes and sediment sorting on steep hillslopes: A case study of clay loam soil from the Loess Plateau, China
NASA Astrophysics Data System (ADS)
Wang, L.; Shi, Z. H.; Wang, J.; Fang, N. F.; Wu, G. L.; Zhang, H. Y.
Rainfall kinetic energy (KE) can break down aggregates in the soil surface. A better understanding of sediment sorting associated with various KEs is essential for the development and verification of soil erosion models. A clay loam soil was used in the experiments. Six KEs were obtained (76, 90, 105, 160, 270, and 518 J m-2 h-1) by covering wire screens located above the soil surface with different apertures to change the size of raindrops falling on the soil surface, while maintaining the same rainfall intensity (90 ▒ 3.5 mm h-1). For each rainfall simulation, runoff and sediment were collected at 3-min intervals to investigate the temporal variation of the sediment particle size distribution (PSD). Comparison of the sediment effective PSD (undispersed) and ultimate PSD (dispersed) was used to investigate the detachment and transport mechanisms involved in sediment mobilization. The effective-ultimate ratios of clay-sized particles were less than 1, whereas that of sand-sized particles were greater than 1, suggesting that these particles were transported as aggregates. Under higher KE, the effective-ultimate ratios were much closer to 1, indicating that sediments were more likely transported as primary particles at higher KE owing to an increased severity of aggregate disaggregation for the clay loam soil. The percentage of clay-sized particles and the relative importance of suspension-saltation increased with increasing KE when KE was greater than 105 J m-2 h-1, while decreased with increasing KE when KE was less than 105 J m-2 h-1. A KE of 105 J m-2 h-1 appeared to be a threshold level beyond which the disintegration of aggregates was severe and the influence of KE on erosion processes and sediment sorting may change. Results of this study demonstrate the need for considering KE-influenced sediment transport when predicting erosion.
Hiromu Isaka [Kansai Electric Power Company (Japan); Masatsugu Tsutsumi; Tadashi Shiraishi [Mitsubishi Heavy Industries Ltd. (Japan); Hiroyuki Kobayashi [Japan Atomic Power Company (Japan)
The authors performed experimental study for the purpose of the following two items from a viewpoint of cavitation erosion of a cylindrical orifice in view of a problem at the letdown orifice in PWR (Pressurized Water Reactor). 1. To get the critical cavitation parameter of the cylindrical orifice to establish the design criteria for prevention of cavitation erosion, and 2. to ascertain the erosion rate in such an eventuality that the cavitation erosion occurs with the orifice made of stainless steel with precipitation hardening (17-4-Cu hardening type stainless steel), so that we confirm the appropriateness of the design criteria. Regarding the 1. item, we carried out the cavitation tests to get the critical cavitation parameters inside and downstream of the orifice. The test results showed that the cavitation parameter at inception is independent of the length or the diameter of the orifice. Moreover, the design criteria of cavitation erosion of cylindrical orifices have been established. Regarding the 2. item, we tested the erosion rate under high-pressure conditions. The cavitation erosion actually occurred in the cylindrical orifice at the tests that was strongly resemble to the erosion occurred at the plant. It will be seldom to reproduce resemble cavitation erosion in a cylindrical orifice with the hard material used at plants. We could establish the criteria for preventing the cavitation erosion from the test results. (authors)
Transforming Creative Potential in Project Networks: How TV Movies Are Produced under Network-Based Control
Stephan Manning; J÷rg Sydow
Project networks have been identified as dynamic, yet relatively stable organizational forms in project-based creative industries. They materialize in longer-term actor relationships which are actualized by and institutionalized through particular projects. This article examines how project networks transform creative potential for and beyond particular projects. The transformation process is enabled and constrained by the dialectic of network-based control which refers
Eolian erosion of the Martian surface. I - Erosion rate similitude
NASA Technical Reports Server (NTRS)
Iversen, J. D.; White, B. R.; Greeley, R.; Pollack, J. B.
A similitude parameter is derived which is based on theoretical considerations of erosion due to sand in saltation. This parameter has been used to correlate wind tunnel experiments of particle flow over model craters. The characteristics of the flow field in the vicinity and downstream of a crater are discussed and it is shown that erosion is initiated in areas lying under a pair of trailing vortices. The erosion rate parameter is used to calculate erosion rates on Mars, reported in Part 2, to be published later.
The economics of tobacco control: evidence from the International Tobacco Control (ITC) Policy Evaluation Project.
Tauras, John A; Chaloupka, Frank J; Quah, Anne Chiew Kin; Fong, Geoffrey T
Over the past few decades, the importance of economic research in advancing tobacco control policies has become increasingly clear. Extensive research has demonstrated that increasing tobacco taxes and prices is the single most cost-effective tobacco control measure. The research contained in this supplement adds to this evidence and provides new insights into how smokers respond to tax and price changes using the rich data on purchase behaviours, brand choices, tax avoidance and evasion, and tobacco use collected systematically and consistently across countries and over time by the International Tobacco Control (ITC) Project. The findings from this research will help inform policymakers, public health professionals, advocates, and others seeking to maximise the public health and economic benefits from higher taxes. PMID:24500268
Guidance and Control Software Project Data - Volume 4: Configuration Management and Quality Assurance Documents
NASA Technical Reports Server (NTRS)
Hayhurst, Kelly J. (Editor)
The Guidance and Control Software (GCS) project was the last in a series of software reliability studies conducted at Langley Research Center between 1977 and 1994. The technical results of the GCS project were recorded after the experiment was completed. Some of the support documentation produced as part of the experiment, however, is serving an unexpected role far beyond its original project context. Some of the software used as part of the GCS project was developed to conform to the RTCA/DO-178B software standard, "Software Considerations in Airborne Systems and Equipment Certification," used in the civil aviation industry. That standard requires extensive documentation throughout the software development life cycle, including plans, software requirements, design and source code, verification cases and results, and configuration management and quality control data. The project documentation that includes this information is open for public scrutiny without the legal or safety implications associated with comparable data from an avionics manufacturer. This public availability has afforded an opportunity to use the GCS project documents for DO-178B training. This report provides a brief overview of the GCS project, describes the 4-volume set of documents and the role they are playing in training, and includes configuration management and quality assurance documents from the GCS project. Volume 4 contains six appendices: A. Software Accomplishment Summary for the Guidance and Control Software Project; B. Software Configuration Index for the Guidance and Control Software Project; C. Configuration Management Records for the Guidance and Control Software Project; D. Software Quality Assurance Records for the Guidance and Control Software Project; E. Problem Report for the Pluto Implementation of the Guidance and Control Software Project; and F. Support Documentation Change Reports for the Guidance and Control Software Project.
The Monitoring Erosion of Agricultural Land and spatial database of erosion events
NASA Astrophysics Data System (ADS)
Kapicka, Jiri; Zizala, Daniel
In 2011 originated in The Czech Republic The Monitoring Erosion of Agricultural Land as joint project of State Land Office (SLO) and Research Institute for Soil and Water Conservation (RISWC). The aim of the project is collecting and record keeping information about erosion events on agricultural land and their evaluation. The main idea is a creation of a spatial database that will be source of data and information for evaluation and modeling erosion process, for proposal of preventive measures and measures to reduce negative impacts of erosion events. A subject of monitoring is the manifestations of water erosion, wind erosion and slope deformation in which cause damaged agriculture land. A website, available on http://me.vumop.cz, is used as a tool for keeping and browsing information about monitored events. SLO employees carry out record keeping. RISWC is specialist institute in the Monitoring Erosion of Agricultural Land that performs keeping the spatial database, running the website, managing the record keeping of events, analysis the cause of origins events and statistical evaluations of keeping events and proposed measures. Records are inserted into the database using the user interface of the website which has map server as a component. Website is based on database technology PostgreSQL with superstructure PostGIS and MapServer UMN. Each record is in the database spatial localized by a drawing and it contains description information about character of event (data, situation description etc.) then there are recorded information about land cover and about grown crops. A part of database is photodocumentation which is taken in field reconnaissance which is performed within two days after notify of event. Another part of database are information about precipitations from accessible precipitation gauges. Website allows to do simple spatial analysis as are area calculation, slope calculation, percentage representation of GAEC etc.. Database structure was designed on the base of needs analysis inputs to mathematical models. Mathematical models are used for detailed analysis of chosen erosion events which include soil analysis. Till the end 2012 has had the database 135 events. The content of database still accrues and gives rise to the extensive source of data that is usable for testing mathematical models.
NASA Technical Reports Server (NTRS)
2004-01-0124 June 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the results of erosion acting upon a layer of material in the south polar region of Mars. The elliptical pit in the lower left corner of the image was once buried beneath this eroding layer, as well. The processes that eroded the material, and the composition of the material, are unknown. The image is located near 80.7oS, 300.9oW, and covers an area about 3 km (1.9 mi) wide. Sunlight illuminates this scene from the top.
NASA Technical Reports Server (NTRS)
2004-01-0109 August 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the effects of severe wind erosion of layered sedimentary rock in the Aeolis region of Mars. The sharp ridges formed by wind movement from the lower left (southwest) toward top/upper right (northeast) are known as yardangs. The dark patches in the lower half of the image are sand dunes. This scene is located near 5.0oS, 203.7oW, and covers an area about 3 km (1.9 mi) across. Sunlight illuminates the terrain from the left/upper left.
Effective Monitoring and Control of Outsourced Software Development Projects
NASA Astrophysics Data System (ADS)
Ponisio, Laura; Vruggink, Peter
In our study of four outsourcing projects we discover mechanisms to support managerial decision making during software development processes. We report on Customer Office, a framework used in practice that facilitates reasoning about projects by highlighting information paths and making co-ordination issues explicit. The results suggest a key role of modularisation and standardisation to assist in value creation, by facilitating information flow and keeping the overview of the project. The practical implications of our findings are guidelines for managing outsourcing projects such as to have a modularised view of the project based on knowledge domains and to standardise co-ordination operations.
DiMES divertor erosion experiments on DIII-D
Whyte, D.G. [Institut National de la Recherche Scientifique, Varennes, PQ (Canada); Brooks, J.N. [Argonne National Lab., IL (United States); Wong, C.P.C.; West, W.P. [General Atomics, San Diego, CA (United States); Bastasz, R.; Wampler, W.R. [Sandia National Labs., Albuquerque, NM (United States); Rubinstein, J. [Illinois Univ., Urbana, IL (United States)
The DiMES (Divertor Material Evaluation Studies) mechanism allows insertion of material samples to the lower divertor floor of the DIII-D tokamak. The main purpose of these studies is to measure erosion rates and redeposition mechanisms under tokamak divertor plasma conditions in order to obtain a physical understanding of the erosion/redeposition processes and to determine its implications for fusion power plant plasma facing components. Thin metal films of Be, W, V, and Mo, were deposited on a Si depth-marked graphite sample and exposed to the steady-state outer strike point on DIII-D. A variety of surface analysis techniques are used to determine the erosion/redeposition of the metals and the carbon after 5--15 seconds of exposure. These short exposure times ensure controlled exposure conditions and the extensive array of DIII-D divertor diagnostics provide a well characterized plasma for modeling efforts. Erosion rates and redeposition lengths are found to decrease with the atomic number of the metallic species, as expected. Under these conditions, the peak net erosion rate for carbon is {approximately} 4 nm/s, with the erosion following the ion flux profile. Comparisons of the measured carbon erosion with REDEP code calculations show good agreement for both the absolute net erosion rate and its spatial variation. Measured erosion rates of the metals are smaller than predicted for sputtering from a bare metal surface, apparently due to effects of carbon deposition on the metal surface. Visible spectroscopic measurements of singly ionized Be have determined that the erosion process reaches steady-state during the exposure.
Dental erosions in subjects living on a raw food diet.
Ganss, C; Schlechtriemen, M; Klimek, J
The aim of the study was to investigate the frequency and severity of dental erosions and its association with nutritional and oral hygiene factors in subjects living on a raw food diet. As part of a larger dietary study 130 subjects whose ingestion of raw food was more than 95% of the total food intake were examined. The median duration of the diet was 39 (minimum 17, maximum 418) months. Before the clinical examination, the participants answered questionnaires and recorded their food intake during a 7-day period. Dental erosions were registered using study models. As a control 76 sex- and age-matched patients from our clinic were randomly selected. The raw food diet records showed the median daily frequency of ingesting citrus fruit to be 4.8 (minimum 0.5, maximum 16.1). The median intake of fruit was 62% (minimum 25%, maximum 96%) of the total, corresponding to an average consumption of 9.5 kg of fruit (minimum 1.5, maximum 23.7) per week. Compared to the control group subjects living on a raw food diet had significantly (p=0.001) more dental erosions. Only 2.3% of the raw food group (13.2% of the controls) had no erosive defects, whereas 37.2% had at least one tooth with a moderate erosion (55.2% of the controls) and 60.5% had at least one tooth with a severe erosion (31.6% of the controls). Within the raw food group no significant correlation was found between nutrition or oral health data and the prevalence of erosions. Nevertheless, the results showed that a raw food diet bears an increased risk of dental erosion compared to conventional nutrition. PMID:9831783
Low frequency cavitation erosion
NASA Astrophysics Data System (ADS)
Pardue, Sally J.; Chandekar, Gautam
Damage of diesel engine piston sleeve liners due to cavitation of the coolant fluid can be severe. Coolant fluid additives are used to inhibit cavitation damage, and are evaluated by industry suppliers using ASTM G32-98 Standard Test Method for Cavitation Erosion Using Vibratory Apparatus. The ASTM G32-98 test procedure uses an ultrasonic horn at 20 kHz to vibrate a test button in the coolant. The test button mass loss and surface appearance are studied to sort the performance of new coolant additives. Mismatch between good lab performers and actual engine test runs has raised concerns over the current lab test. The frequency range of the current test has been targeted for investigation. A low frequency, less than 2000 Hz, test rig was built to explore the cavitation damage. The test system did produce cavitation on the surface of the test button for a period of 36 h, with minimal mass loss. The test rig experienced cyclic fatigue when test times were extended. The work is now focusing on designing a better test rig for long duration tests and on developing numerical models in order to explore the effects of cavitation excitation frequency on surface erosion.
Amy J. C. Trappey; Tzu-An Chiang; Sam Ke
This research develops an intelligent workflow management system (IWMS) to efficiently and effectively manage complex processes of projects, control project flows, and allocate available resources for project execution dynamically across organizational boundaries. Process logics are embedded in predicate (IF-THEN) rules that can be activated when condition is met to drive workflows. In this paper, an expert system inference engine is
The measure of national infrastructure project performance auditing risk's controllability: Based on Chinese experiences empirical study
Liu Ai Dong; Zhao Jin Ling
The performance auditing of national infrastructure project is the important regulatory measure to improve the project's performance, and risk aversion of audit could improve the auditing's quality effectively. The paper conducted investigation in-depth based on the existing research, designed a set of measuring scale for national infrastructure project performance auditing risk's controllability, conducted the crossed empirical study taking 248 effective
Project Controls to Minimize Cost and Schedule Overruns: A Model, Research Agenda, and Initial Results
Ford, David N.
1 of 27 Project Controls to Minimize Cost and Schedule Overruns: A Model, Research Agenda been successfully applied to the study of projects for many years. While this modeling has clearly defined the structures which create project dynamics, it has been less helpful in providing explicit
The Role of Perceived Control, Attention-Shaping, and Expertise in IT Project Risk Assessment
Stephen Du; Mark Keil; Lars Mathiassen; Yide Shen; Amrit Tiwana
This study investigates how individuals assess risks in IT development projects under different conditions. We focus on three conditions: the perceived control over the IT project, the use of an attention-shaping tool, and the expertise of the individual conducting the assessment. A role-playing experiment was conducted including 102 practitioners with high expertise in IT projects and 105 university students with
Experiments for understanding soil erosion processes
NASA Astrophysics Data System (ADS)
Seeger, Manuel
Soil erosion processes are usually quantified by observation and measurement of their related forms. Rill, and gullies, moulds or sediment sinks are often used to estimate the soil loss. These forms are generally related directly to different types of processes, thus are also used to identify the dominant processes on a certain type of land-use. Nevertheless, the direct observation of erosion processes is constrained by their temporal and spatial erratic occurrence. As a consequence, the process understanding is generally deduced by analogies. Another possibility is to reproduce processes in experiments in both, the lab and in the field. Laboratory experiments are implemented when we want to have full control over all parameters we think are relevant for the process in our focus. So are very useful for identification of parameters influencing processes and their intensities, but also as physical models of the processes and process interactions in our focus. Therefore, we can use them to verify our concepts, and to define relevant parameters. Field experiments generally only simulate with controlled driving forces, this is the rain or the runoff, but dealing with the uncertainty of our study object, the soil. This enables two things: 1) similar as with lab experiments, we are able to identify processes and process interactions and so, to get a deeper understanding of soil erosion; 2) experiments are suitable for providing data about singular processes in the field and thus, to provide data suitable for model parametrisation and calibration. These may be quantitative data about erodibility or soil resistance, sediment detachment or transport. The Physical Geography Group at Trier University has a long lasting experience in the application of experiments in soil erosion research in the field, and has become lead in the further development conception and of devices and procedures to investigate splash detachment and initial transport of soil particles by wind and water, rill erosion and the transport of fine and coarse sediments. Herein, rainfall simulations are one of our principal methods, as they can be used easily to study splash processes and to get data about soil erodibility. But therefore, measurements need to be comparable and the methodology very well established and documented. The incorporation of wind into rainfall events, as they usually appear in nature, is a challenge in field experimentation, which has been tackled in cooperation with colleagues from Basel (Switzerland). So, we are one of the few groups in the world able to use a low cost, but efficient rainfall-wind simulator in the field. In addition, to cover erosion processes by concentrated flow, a methodology has been developed for field measurement of erosion processes. In this context, we are focusing now also on the development of sensors to understand the movement of coarse particles (as pebbles) in concentrated flow and to investigate their influence on soil erosion. With this contribution, I would like to promote the use of experiments for soil erosion research, and to provide information and expertise on the design and application of lab and field experiments on all partial processes of soil erosion.
Assessment of the use of sediment fences for control of erosion and sediment phosphorus loss after potato harvesting on sloping land.
Vinten, A J A; Loades, K; Addy, S; Richards, S; Stutter, M; Cook, Y; Watson, H; Taylor, C; Abel, C; Baggaley, N; Ritchie, R; Jeffrey, W
In humid temperate areas, after harvest of potatoes, it is difficult to prevent soil erosion and diffuse pollution. In some autumn weather conditions, in-field mitigation such as cultivation or sowing are not possible, while edge of field measures can be costly and inflexible. We have assessed the potential of modified sediment fences, widely used on building sites, for erosion mitigation post-harvest of potato crops. Field scale assessments were conducted on fields in the Lunan catchment, eastern Scotland. Sediment retention was estimated by two methods: a topographic survey method using a hand held Real Time Kinematic Global Positioning System (RTK-GPS), and direct measurement of sediment depth using a graduated cane. In the 2010/11 trial the main fence comprised 70 m of entrenched fine mesh (0.25 mm) and coarser mesh (4mm) fabric pinned to a contour fence near the base of the field. This retained an estimated 50.9 m(3) (80.2 tonnes) of sediment, with weighted mean total P (TP) content of 0.09 % in the<2mm soil fraction. In the 2011/12 trial, the main 146 m fence was of intermediate mesh size (1.2mm). The fence was partitioned into nine upslope plots, with 3 replicates of each of 3 cultivation methods: T1 (full grubbing--a light, tined cultivator), T2 (partial grubbing) and T3 (no grubbing). Average plot slopes ranged from 9.9 to 11.0 %. The amounts of TP accumulating as sediment at the fences were: 9.3 (sd = 7.8), 11.8 (sd = 10.2) and 25.7 (sd = 5.8)kg P/ha of upslope plot for the T1, T2 and T3 treatments respectively. PMID:24012897
Reprint of: Assessment of the use of sediment fences for control of erosion and sediment phosphorus loss after potato harvesting on sloping land.
Vinten, A J A; Loades, K; Addy, S; Richards, S; Stutter, M; Cook, Y; Watson, H; Taylor, C; Abel, C; Baggaley, N; Ritchie, R; Jeffrey, W
In humid temperate areas, after harvest of potatoes, it is difficult to prevent soil erosion and diffuse pollution. In some autumn weather conditions, in-field mitigation such as cultivation or sowing are not possible, while edge of field measures can be costly and inflexible. We have assessed the potential of modified sediment fences, widely used on building sites, for erosion mitigation post-harvest of potato crops. Field scale assessments were conducted on fields in the Lunan catchment, eastern Scotland. Sediment retention was estimated by two methods: a topographic survey method using a hand held Real Time Kinematic Global Positioning System (RTK-GPS), and direct measurement of sediment depth using a graduated cane. In the 2010/11 trial the main fence comprised 70 m of entrenched fine mesh (0.25 mm) and coarser mesh (4mm) fabric pinned to a contour fence near the base of the field. This retained an estimated 50.9 m(3) (80.2 tonnes) of sediment, with weighted mean total P (TP) content of 0.09 % in the<2mm soil fraction. In the 2011/12 trial, the main 146 m fence was of intermediate mesh size (1.2mm). The fence was partitioned into nine upslope plots, with 3 replicates of each of 3 cultivation methods: T1 (full grubbing--a light, tined cultivator), T2 (partial grubbing) and T3 (no grubbing). Average plot slopes ranged from 9.9 to 11.0 %. The amounts of TP accumulating as sediment at the fences were: 9.3 (sd=7.8), 11.8 (sd=10.2) and 25.7 (sd=5.8)kg P/ha of upslope plot for the T1, T2 and T3 treatments respectively. PMID:24200093
Krovi, Venkat
THE SMART CAR PROJECT: A CASE STUDY IN COMPUTER-MEDIATED CONTROL by O. Daniel Gott A project autonomy into human/robot interaction. We chose to examine two sets of tasks to help enhance a remote a mobile robot system (a 1/10 scale remote control truck equipped with Basic Stamp 2 microprocessors
A test bed for the future access control system:the AD Project
L Scibile
This paper describes the design, management and development of the new access control system for the Antiproton Deceleration experimental area, called the AD Project. As this project includes all the elements for the industrial evolution of the present access control system it is an ideal test bed for future access systems. The adoption of new technologies and techniques are described,
Know Your Enemy: The Use of Molecular Ecology in the Onopordum Biological Control Project
Experience has repeatedly shown that accurate identification of the target weed(s) for a biological control project is critical to the success of a biological control project. This is particularly true where the weed may comprise different biotypes or be part of a species complex, where hybridisation is suspected or where the agent - host plant relationship is very tight. Molecular
Is splash erosion potential species specific? Measuring of splash erosion potential under forest in different succession stages along a biodiversity gradient in the humid subtropics
NASA Astrophysics Data System (ADS)
Gei▀ler, C.; K³hn, P.; Scholten, T.
It is widely accepted that (forest) vegetation is a key control for the type and intensity of soil erosion. The current paradigm is that natural or quasi-natural vegetation protects the soil from erosion and that agricultural vegetation or land use generally enhances erosion. The latter was in focus of most research during the last decades and less interest was paid on natural systems, which are more difficult to study. Nevertheless, afforestation is widely used as a measure of soil protection against soil erosion. Rainfall can be highly erosive particularly in the humid subtropics. Regarding climate change, also precipitation regime may change in direction to even more severe storms and higher rainfall intensities; it is a research field of growing importance. Key mechanisms of a vegetation cover in reducing or enhancing erosion are modifications of drop-size distribution, retention of raindrop impact on the soil and changes in amount and spatial distribution of rainfall at the ground surface. Controlling determinants are rainfall intensity, drop size distribution, drop fall velocity, height of the canopy as well as density of the canopy, crown and leaf traits, LAI and coverage by a litter layer. Large drops are supposed to be significant sources of splash detachment in forests (Brandt 1989; Vis 1986). However, the mechanisms of reducing (or enhancing?) splash detachment under forest in relation to species richness and species composition are not well understood. Some studies indicate that raindrop impact is species specific (Calder 2001; Nanko et al. 2006) and some neglect the effects of species specific impacts (Foot & Morgan 2005). Our research uses different methods of rainfall characterization (splash cups, tipping-bucket rain gauge, laser distrometer) to reveal the described mechanisms from the canopy through different vegetation layers to the ground. First results of splash cup measurements (revised after Ellison 1947) show that sand loss under vegetation is 2.5 times higher than in open field despite the fact that only 60 percent of open field rainfall reaches the ground. The results also indicate that sand loss is a function of the age of the specific forest stand and the variability of sand loss under different species with respect to space and time. These and future results will help managing afforestation projects in giving implications which of the species (resp. species compositions) may reduce most effectively potential splash erosion. References: Brandt, C. J. (1989): The size distribution of throughfall drops under vegetation canopies. Catena 16, p. 507-524. Calder, I. R. (2001): Canopy processes: implications for transpiration, interception and splash induced erosion, ultimately for forest management and water resources. Plant Ecology 153, p. 203-214. Ellison, W. D. (1947): Soil Erosion Studies - Part II. Soil Detachment Hazard by Raindrop Splash. Agricultural Engineering 28, p. 197-201. Foot, K.; Morgan, R. P. C. (2005): The role of leaf inclination, leaf orientation and plant canopy architecture in soil particle detachment by raindrops. Earth Surface Processes and Landforms 30, p. 1509-1520. Nanko, K.; Hotta, N. & Suzuki, M. (2006): Evaluating the influence of canopy species and meteorological factors on throughfall drop size distribution. Journal of Hydrology 329, p. 422-431. Vis, M. (1986): Interception, drop size distributions and rainfall kinetic energy in four colombian forest ecosystems. Earth Surface Processes and Landforms 11, p. 591-603.
Adaptation of Rhizome Connections in Drylands: Increasing Tolerance of Clones to Wind Erosion
Yu, Fei-Hai; Wang, Ning; He, Wei-Ming; Chu, Yu; Dong, Ming
Background and Aims Wind erosion is a severe stress for plants in drylands, but the mechanisms by which plants withstand erosion remain largely unknown. Here, the hypothesis is tested that maintaining rhizome connections helps plants to tolerate erosion. Methods Five transects were established across an inland dune in Inner Mongolia, China, and measurements were made of leaf number, biomass per ramet and rhizome depth of Psammochloa villosa in 45 plots. In 40 ū 40 cm plots of P. villosa on another dune, the top 15 or 30 cm of sand was removed for 1Ę5 or 3 months to simulate short- and long-term moderate and severe erosion, respectively, with untreated plots as controls, and the rhizomes at the edges of half of the plots were severed to mimic loss of rhizome connections. Key Results Leaf number and biomass per ramet showed quadric relationships with rhizome depth; when rhizomes were exposed to the air, the associated ramets either died or became very weak. Ramet number, leaf number and biomass per plot decreased with increasing erosion severity. Rhizome connections did not affect these traits under control or short-term erosion, but increased them under long-term erosion. Conclusions Rhizome connections alleviated the negative effects of erosion on P. villosa, very likely because the erosion-stressed ramets received water and/or photosynthates translocated from those connected ramets that were not subject to erosion. This study provides the first evidence that maintaining rhizome connections helps plants to tolerate erosion in drylands. PMID:18621966
Coastal Change Along the Shore of Northeastern South Carolina: The South Carolina Coastal Erosion Study
Barnhardt, W. A., (Edited By)
The U.S. Geological Survey, in cooperation with the South Carolina Sea Grant Consortium, conducted a 7-year, multi-disciplinary study of coastal erosion in northeastern South Carolina. The main objective was to understand the geologic and oceanographic processes that control sediment movement along the region's shoreline and thereby improve projections of coastal change. The study used high-resolution remote sensing and sampling techniques to define the geologic framework and assess historic shoreline change. Based on these findings, oceanographic-process studies and numerical modeling were carried out to determine the rates and directions of sediment transport along South Carolina's Grand Strand.
The Horton (1945) infiltration model of surface runoff and erosion is shown to be of much more limited geomorphic application than has been recognised hitherto. It is most applicable to clay badlands with low infiltration capacities and little weathered cover, and is one end-member of a wide spectrum of erosion models. The other end-member applies to slopes with high infiltration
Technology Transfer Automated Retrieval System (TEKTRAN)
The erosion process involves detachment of soil particles from a soil surface and transport of these particles from their first location. The main agents that loosen, break down, and carry the soil particles are wind and water. Wind and water erosion processes have traditionally been separately stu...
Spent Nuclear Fuel Project document control and Records Management Program Description
The Spent Nuclear Fuel (SNF) Project document control and records management program, as defined within this document, is based on a broad spectrum of regulatory requirements, Department of Energy (DOE) and Project Hanford and SNF Project-specific direction and guidance. The SNF Project Execution Plan, HNF-3552, requires the control of documents and management of records under the auspices of configuration control, conduct of operations, training, quality assurance, work control, records management, data management, engineering and design control, operational readiness review, and project management and turnover. Implementation of the controls, systems, and processes necessary to ensure compliance with applicable requirements is facilitated through plans, directives, and procedures within the Project Hanford Management System (PHMS) and the SNF Project internal technical and administrative procedures systems. The documents cited within this document are those which directly establish or define the SNF Project document control and records management program. There are many peripheral documents that establish requirements and provide direction pertinent to managing specific types of documents that, for the sake of brevity and clarity, are not cited within this document.
Physical modeling and monitoring of the process of thermal-erosion of an ice-wedge during a partially-controlled field experiment (Bylot Island, NU, Canada)
NASA Astrophysics Data System (ADS)
Godin, E.; Fortier, D.
Syngenetic ice-wedges polygons are widespread periglacial features of the Arctic. On Bylot Island, Nunavut, Canada, numerous thermo-erosion gullies up to several 100's m in length developed in polygonal wetlands during the last decades. These gullies contributed to drainage of these wetlands and changed dramatically local ecological conditions. Concentrated and repeated snowmelt surface runoff infiltrated frost cracks, where convective heat transfer between flowing water and ice initiated piping in ice wedges leading to the rapid development of tunnels and gullies in the permafrost (Fortier D. et al., 2007). We conducted field experiments to quantify the convection process and speed of ice wedges ablation. The experiments were accomplished between the 23/06/2013 and the 05/07/2013 over A; an exposed sub-horizontal ice-wedge surface and B; a tunnel in an ice-wedge crack. The ice was instrumented with graduated sticks to calculate the ice ablation following the flow of a defined amount of water. A fixed quantity of water obtained from a nearby waterfall was diverted over the ice through a PVC pipe. Water temperature Wt (K), quantity Wq (L s-1 or m3 s-1), ice ablation rate Iar (m s-1) and convective heat transfer coefficient ? (W m-2 K) were obtained during the 5 experiments. The objective of this paper is to quantify the heat transfer process from field measurements from an ice wedge under ablation and to compare with coefficients from previous researches and in the literature. For each experiment with the ice-surface scenario, water temperature varied between 280 K and 284 K. Discharge varied between 0.0001 and 0.0003 m3 s-1. Ablation rate varied between 1.8 * 10-5 and 0.0004 m s-1. Heat transfer coefficient varied between 706 and 11 655 W m-2 K and between 54 and 4802 W of heat was transferred to ice. For each experiment with the tunnel scenario, water temperature was 284 K ū 1 K. Discharge was 0.0002 m3 s-1. Ablation rate varied between 0.0001 and 0.0003 m s-1. Heat transfer coefficient varied between 2644 and 7934 W m-2 K and between 1791 and 5374 W of heat was transferred to ice. Water temperature exiting the tunnel was less than 279 K. Both contexts of experimentation are occurring frequently during gully development. A small input of water over exposed massive-ice can erode significant volume of ice-wedges ice, thermally and mechanically. Empiric determination of the heat transfer coefficient using the parameters measured in the field will provide a better understanding of water temperature and discharge relative importance in the thermo-erosion of ice. Fortier, D., Allard, M., et al. (2007). "Observation of rapid drainage system development by thermal erosion of ice wedges on Bylot island, Canadian Arctic Archipelago." Permafrost and Periglacial Processes 18(3): 229-243.
Reduction of Gun Erosion and Correlation of Gun Erosion Measurements
NASA Technical Reports Server (NTRS)
Bogdanoff, Dave; Wercinski, Paul (Technical Monitor)
Gun barrel erosion is serious problem with two-stage light gas guns. Excessive barrel erosion can lead to poor or failed launches and frequent barrel changes, with the corresponding down time. Also, excessive barrel erosion can limit the maximum velocity obtainable by loading down the hydrogen working gas with eroded barrel material. Guided by a CFD code, the operating conditions of the Ames 0.5-inch gun were modified to reduce barrel erosion. The changes implemented included: (1) reduction in the piston mass, powder mass and hydrogen fill pressure; and (2) reduction in pump tube volume, while maintaining hydrogen mass. The latter change was found, in particular, to greatly reduce barrel erosion. For muzzle velocity ranges of 6.1 - 6.9 km/sec, the barrel erosion was reduced by a factor of 10. Even for the higher muzzle velocity range of 7.0 - 8.2 km/sec, the barrel erosion was reduced by a factor of 4. Gun erosion data from the Ames 0.5-inch, 1.0-inch, and 1.5-inch guns operated over a wide variety of launch conditions was examined and it was found that this data could be correlated using four different parameters: normalized powder charge energy, normalized hydrogen energy density, normalized pump tube volume and barrel diameter. The development of the correlation and the steps used to collapse the experimental data are presented. Over a certain parameter range in the correlation developed, the barrel erosion per shot is found to increase very rapidly. The correlation should prove useful in the selection of gun operating conditions and the design of new guns. Representative shapes of eroded gun barrels are also presented.
Project: Driver and controller for a thermoelectric cooler
the temperature Ł heating or cooling. Obviously, these one- directional control Methods are not the most efficient solutions. Based on one of the three thermoelectric phenomena Ł the Peltier effect Ł bi-directional control
A revealed preference approach to estimating supply curves for ecosystem services: use of auctions to set payments for soil erosion control in Indonesia.
Jack, B Kelsey; Leimona, Beria; Ferraro, Paul J
To supply ecosystem services, private landholders incur costs. Knowledge of these costs is critical for the design of conservation-payment programs. Estimating these costs accurately is difficult because the minimum acceptable payment to a potential supplier is private information. We describe how an auction of payment contracts can be designed to elicit this information during the design phase of a conservation-payment program. With an estimate of the ecosystem-service supply curve from a pilot auction, conservation planners can explore the financial, ecological, and socioeconomic consequences of alternative scaled-up programs. We demonstrate the potential of our approach in Indonesia, where soil erosion on coffee farms generates downstream ecological and economic costs. Bid data from a small-scale, uniform-price auction for soil-conservation contracts allowed estimates of the costs of a scaled-up program, the gain from integrating biophysical and economic data to target contracts, and the trade-offs between poverty alleviation and supply of ecosystem services. Our study illustrates an auction-based approach to revealing private information about the costs of supplying ecosystem services. Such information can improve the design of programs devised to protect and enhance ecosystem services. PMID:18983597
Soil erosion in developing countries: A politicoeconomic explanation
NASA Astrophysics Data System (ADS)
Thapa, Gopal B.; Weber, Karl E.
Soil erosion is accelerating in developing countries of Asia, Africa, and Latin America. It has threatened the livelihood of millions of peasants, for agriculture is their economic mainstay. A probe into the forces causing erosion reveals that the eliteÆs resolve to accumulate ever more wealth and to maintain, consolidate, or expand their sociopolitical power and the necessity of the poor to fulfill their requirements of food, fuelwood, and fodder are the two major factors accelerating soil erosion. Unless the vast masses of poor people are integrated into the national mainstream through the implementation of equitable and redistributive development policies, it is impossible to control the accelerating rate of soil erosion and thus to achieve the objective of sustainable development.
An holistic approach to beach erosion vulnerability assessment.
Alexandrakis, George; Poulos, Serafim ?
Erosion is a major threat for coasts worldwide, beaches in particular, which constitute one of the most valuable coastal landforms. Vulnerability assessments related to beach erosion may contribute to planning measures to counteract erosion by identifying, quantifying and ranking vulnerability. Herein, we present a new index, the Beach Vulnerability Index (BVI), which combines simplicity in calculations, easily obtainable data and low processing capacity. This approach provides results not only for different beaches, but also for different sectors of the same beach and enables the identification of the relative significance of the processes involved. It functions through the numerical approximation of indicators that correspond to the mechanisms related to the processes that control beach evolution, such as sediment availability, wave climate, beach morhodynamics and sea level change. The BVI is also intended to be used as a managerial tool for beach sustainability, including resilience to climate change impact on beach erosion. PMID:25123815
The SECAD project - vulnerability reduction via propulsion control logic
A. Pisano; C. E. Frankenberger
Digital propulsion controls provide the foundation for adding capabilities beyond normal control functions to enable the next level of increased survivability for both war-time and peace-time damage scenarios. Propulsion is a critical system for any platform, providing electrical and hydraulic power, ECS (environmental control system) air as well as thrust. If the vulnerability of propulsion systems can be reduced, the
Gatto, L.W. (Army Cold Regions Research and Engineering Lab., Hanover, NH (United States). Geological Sciences Branch)
River and lake bank erosion is caused by multiple processes and influenced by many conditions that interact in complex ways. Their importance will vary spatially and temporally due in large part to regional and seasonal differences in climate, hydrology and soils. In cold areas, these normally complex interactions are further complicated because the same process or condition may cause erosion at one time and prevent erosion at another. Bank sediments when frozen may be more resistant to erosion than when unfrozen. However, during the process of freezing, soil structure can be disrupted and sediment pore water can be drawn to the freezing zone within the soil; ice formation may make bank sediment more susceptible to erosion during spring thaw. Ice that has been forced onto and piled upon a shore by wind or thermal expansion can cause considerable localized damage and yet can also protect shores against winter waves and nearshore currents. Ice push can form sediment ramparts that protect the toe of a bank. Spray from winds and waves can freeze to banks, covering them with a protective layer of ice. When river or lake water levels are high enough, however, ice can erode banks by shoving, gouging and disrupting bank sediment. This paper reviews the state of knowledge regarding the importance of cold regions factors in determining the erodibility and erosion of bank sediments. Ongoing investigations to improve methods of erosion prediction in cold climates will also be detailed.
Runoff and inter-rill erosion at the micro-plot scale following wildfire: comparing simulated and natural rainfall conditions
Maruxa Malvar; JoŃo. Pedro Nunes; Peter Robichaud; Jan Jacob Keizer
Post-fire erosion has been an important issue in recent years due to the increasing number of fires. Monitoring post-fire erosion in this study is part of the EROSFIRE project (POCI\\/AGR\\/60354\\/2004), funded by the Portuguese Foundation for Science and Technology (FCT). Overall, the project will evaluate the suitability of rainfall simulation experiments (RSE's) to assess and model soil erosion hazard in
Impact of Precipitation Changes on Runoff and Soil Erosion in Korea using CLIGEN and WEPP
Technology Transfer Automated Retrieval System (TEKTRAN)
The quality of spatially and temporally distributed weather information is critical in soil erosion model results because of the primary influence of rainfall on runoff and soil movement. Detailed climate data for the Water Erosion Prediction Project (WEPP) model can be generated by a climate genera...
Does WEPP meet the specificity of soil erosion in steep mountain regions?
Technology Transfer Automated Retrieval System (TEKTRAN)
We chose the USDA-ARS-WEPP model (Water Erosion Prediction Project) to describe the soil erosion in the Urseren valley (Central Switzerland) as it seems to be one of the most promising models for steep mountain environments. Crucial model parameters were determined in the field (slope, plant species...
Cropping and tillage systems effects on soil erosion under climate change in Oklahoma
Technology Transfer Automated Retrieval System (TEKTRAN)
Soil erosion under future climate change is very likely to increase due to projected increases in frequency and magnitude of heavy storms. The objective of this study is to quantify the effects of common cropping and tillage systems on soil erosion and surface runoff during 2010-2039 in central Okl...
Effects of cropping and tillage systems on soil erosion under climate change in Oklahoma
Technology Transfer Automated Retrieval System (TEKTRAN)
Soil erosion under future climate change is very likely to increase due to projected increases in frequency and magnitude of heavy storms. The objective of this study is to quantify the effects of common cropping and tillage systems on soil erosion and surface runoff during 2010-2039 in central Okl...
Potential change in soil erosion trend and risk during 2010-2039 in central Oklahoma, USA
Technology Transfer Automated Retrieval System (TEKTRAN)
The potential for global climate changes to increase risk of soil erosion is clear, but quantitative analysis of this risk is limited due to high spatial and temporal variability in projected climate change scenarios. For accurate prediction of soil erosion risk under climate change, climate chang...
Technology Transfer Automated Retrieval System (TEKTRAN)
Control of soil erosion and associated nonpoint source pollution is essential to improving water quality. The use of compost or mulch blankets as a soil cover can help control soil erosion and provide sustainable alternatives to disposal for many biomass resources. To effectively utilize compost a...
Cavitation erosion size scale effects
NASA Technical Reports Server (NTRS)
Rao, P. V.; Buckley, D. H.
Size scaling in cavitation erosion is a major problem confronting the design engineers of modern high speed machinery. An overview and erosion data analysis presented in this paper indicate that the size scale exponent n in the erosion rate relationship as a function of the size or diameter can vary from 1.7 to 4.9 depending on the type of device used. There is, however, a general agreement as to the values of n if the correlations are made with constant cavitation number.
Experimental evidence for bedrock erosion by suspended sediment
NASA Astrophysics Data System (ADS)
Scheingross, J. S.; Brun, F.; Lo, D. Y.; Omerdin, K.; Lamb, M. P.
Fluvial bedrock incision influences channel evolution and sets the pace of landscape lowering. Bedrock incision often occurs via abrasion, and existing theory is divided on the erosional efficiency of sediment transported in suspension versus bed load, due in part to a lack of data to test model predictions. This represents a major knowledge gap as suspended sediment can account for the majority of the total fluvial sediment load, and untested models make opposite predictions of bedrock erosion in steep channels and during large floods. We performed controlled abrasion mill experiments examining suspended and bed load erosion, making use of an erodible polyurethane foam substrate as a bedrock analog to overcome previous experimental limitations and allow for measureable suspension erosion. Our results show foam erodes similar to natural rock, where erodibility is a function of tensile strength and density. To explore the role of the mode of sediment transport on erosion, we varied sediment size from gravel (42 mm diameter) to medium sand (0.4 mm diameter), while holding fixed hydraulics, sediment load, and substrate strength. Under these conditions, volumetric erosion rates decreased across the bed load (~101 - 103 cm3/hr) to suspended load (~0.01 - 100 cm3/hr) transition due to lower near-bed sediment concentrations (~25 g/l vs. 115 g/l), slower settling velocity (0.09 m/s vs. 0.49 m/s), and viscous damping of impacts (for particle Stokes numbers less than ~75) for suspended particles. Our results provide direct experimental evidence of erosion by suspended load, and upscaling results to field scale shows suspension erosion can outpace bed load erosion by up to a factor ~4 during large floods which suspend coarse sand and gravel, and where suspended sediment dominates the total load. These results imply that suspension erosion may also dominate on very steep slopes where commonly used bedrock incision models (which ignore suspension erosion) predict zero erosion. For small floods and low sloping channels where suspension is limited to sand, suspension erosion will have a reduced role because of comparatively low impact energies and viscously damped collisions.
Vibration control with adaptive structures: MAVO FASPAS project review
NASA Astrophysics Data System (ADS)
Hanselka, Holger; Melz, Tobias; Drossel, Welf-Guntram; Sporn, Dieter; Sch÷necker, Andreas; Poignķ, Axel
The mission of the Fraunhofer Gesellschaft, one of the biggest research facilities in Germany, is to identify technologies with a high impact potential for commercial applications and to take all necessary steps to successfully promote them by performing cooperative industrial research activities. One of these technologies is called smart structures, also known as adaptive structures. Most recently, Fraunhofer decided to strategically extend its portfolio to include this technology and summarize its R&D activities in the FIT (Fraunhofer Innovation Topics) ADAPTRONIK. To improve Fraunhofer's competencies in adaptronics, especially with respect to system design and implementation, the Fraunhofer internal project MAVO FASPAS was launched in 2003. Now, after 3 years of work, the project comes to a close. This article discusses some major project results.
The interaction between soil erosion and soil organisms in temperate agroecosystems: nematode redistribution in tramlines
NASA Astrophysics Data System (ADS)
Baxter, Craig; Rowan, John S.; McKenzie, Blair M.; Neilson, Roy
Arable agriculture presents a unique set of challenges, and one of the most important is soil erosion. Whilst policy and practice look towards sustainable intensification of production to ensure food security, fundamental gaps in our understanding still exist. The physical processes involved in the detachment, transport and deposition of soil are well characterised but further research considering chemical and nutrient transport, fertiliser and pesticide losses, and environmental impacts to downstream environments is still required. Furthermore the interaction between soil erosion and soil organisms have largely been ignored, even though soil organisms serve a myriad of functions essential in the provision of soil ecosystem goods and services. Here we present the findings of a field-scale experiment into soil biotic redistribution undertaken at the James Hutton Institute's Balruddery Farm, Scotland (Link Tramlines Project XDW8001). Farm vehicle-tyre wheelings left in arable fields (tramlines) to enable crop spraying during the crop growth cycle have been identified as key transport pathways for sediment and associated nutrients. We tested the hypothesis that soil organisms were also transported by tramline erosion. During the winter of 2012/13 an experiment was undertaken to measure soil organism export from unbound hillslope plots subject to four different tramline treatments set out in a randomised block design. We used soil nematodes as a model organism as they are ubiquitous and sensitive to disturbance and an established indicator taxa of biological and physico-chemical changes in soil. Tramline treatments included a control tyre (conventional tractor tyre), a control tyre with a sown tramline, a low pressure tyre with sown tramline, and a control tyre with a spiked harrow. Post-event sampling of rainfall events was undertaken, and a range of variables measured in the laboratory. The spiked harrow treatment produced the greatest overall reductions in nematode export with 95% less nematodes exported, compared with the control treatment. We observed wholesale non-selective transport of all nematode trophic groups present in the soil. The findings of this experiment are twofold. Firstly, we demonstrate that soil organisms are transported by erosion processes and confirm that tramlines are key hydrological pathways. Secondly, we highlight practical on-farm solutions that have potential to decrease soil organism losses. These results provide important baseline information to improve our understanding of soil erosion impacts to the wider soil ecosystem. The results help to inform soil and water conservation measures for sustainable agriculture.
Critical issues in process control system security : DHS spares project.
Hernandez, Jacquelynne; McIntyre, Annie; Henrie, Morgan
The goals of this event are: (1) Discuss the next-generation issues and emerging risks in cyber security for control systems; (2) Review and discuss common control system architectures; (3) Discuss the role of policy, standards, and supply chain issues; (4) Interact to determine the most pertinent risks and most critical areas of the architecture; and (5) Merge feedback from Control System Managers, Engineers, IT, and Auditors.
Hydraulic wellbore erosion while drilling
Chemerinski, B. [British Borneo Exploration, Houston, TX (United States); Robinson, L. [OGCI, Houston, TX (United States)
This article is the first to identify nozzle hydraulic effects in a field evaluation of hole erosion. Common practice normally identifies annular velocity as the culprit for excessive hole washout. But field tests in this article clearly identify excessive nozzle hydraulics as the cause for hole erosion. Both oil-based and water-based drilling fluids were used during the field test. The primary contribution of this study is a simple guideline to assist drillers in preventing excessive hole erosion. This article describes drilling conditions and caliper logs, and discusses sequences of events that could explain the observations. Some preliminary guidelines are presented so that drillers can prevent erosion of the wellbore from high shear rates at bit nozzles.
Lithosphere erosion atop mantle plumes
NASA Astrophysics Data System (ADS)
Agrusta, R.; Arcay, D.; Tommasi, A.
Mantle plumes are traditionally proposed to play an important role in lithosphere erosion. Seismic images beneath Hawaii and Cape Verde show a lithosphere-asthenosphere-boundary (LAB) up to 50 km shallower than the surroundings. However, numerical models show that unless the plate is stationary the thermo-mechanical erosion of the lithosphere does not exceed 30 km. We use 2D petrological-thermo-mechanical numerical models based on a finite-difference method on a staggered grid and marker in cell method to study the role of partial melting on the plume-lithosphere interaction. A homogeneous peridotite composition with a Newtonian temperature- and pressure-dependent viscosity is used to simulate both the plate and the convective mantle. A constant velocity, ranging from 5 to 12.5 cm/yr, is imposed at the top of the plate. Plumes are created by imposing a thermal anomaly of 150 to 350 K on a 50 km wide domain at the base of the model (700 km depth); the plate right above the thermal anomaly is 40 Myr old. Partial melting is modeled using batch-melting solidus and liquidus in anhydrous conditions. We model the progressive depletion of peridotite and its effect on partial melting by assuming that the melting degree only strictly increases through time. Melt is accumulated until a porosity threshold is reached and the melt in excess is then extracted. The rheology of the partially molten peridotite is determined using viscous constitutive relationship based on a contiguity model, which enables to take into account the effects of grain-scale melt distribution. Above a threshold of 1%, melt is instantaneously extracted. The density varies as a function of partial melting degree and extraction. Besides, we analyze the kinematics of the plume as it impacts a moving plate, the dynamics of time-dependent small-scale convection (SSC) instabilities developing in the low-viscosity layer formed by spreading of hot plume material at the lithosphere base, and the resulting thermal rejuvenation of the lithosphere. The onset time and the vigor of SSC and, hence, the new equilibrium thermal state of the lithosphere atop the plume wake depends on the Rayleigh number (Ra) in the unstable layer at the base of the lithosphere, which is controlled by the temperature anomaly and rheology in the plume-fed layer. For vigorous, hot plumes, SSC onset times do not depend on plate velocity. For more sluggish plumes, SSC onset times decrease with increasing plate velocity. This behavior is explained by differences in the thermal structure of the lithosphere, due to variations in the spreading behavior of the plume material at the lithosphere base. Reduction of the viscosity in partial molten areas and decrease in density of the depleted residuum enhance the vigor of small-scale convection in the plume-fed low-viscosity layer at the lithosphere base, leading to more effective erosion of the base of the lithosphere.
Determination of riverbank erosion probability using Locally Weighted Logistic Regression
NASA Astrophysics Data System (ADS)
Ioannidou, Elena; Flori, Aikaterini; Varouchakis, Emmanouil A.; Giannakis, Georgios; Vozinaki, Anthi Eirini K.; Karatzas, George P.; Nikolaidis, Nikolaos
Riverbank erosion is a natural geomorphologic process that affects the fluvial environment. The most important issue concerning riverbank erosion is the identification of the vulnerable locations. An alternative to the usual hydrodynamic models to predict vulnerable locations is to quantify the probability of erosion occurrence. This can be achieved by identifying the underlying relations between riverbank erosion and the geomorphological or hydrological variables that prevent or stimulate erosion. Thus, riverbank erosion can be determined by a regression model using independent variables that are considered to affect the erosion process. The impact of such variables may vary spatially, therefore, a non-stationary regression model is preferred instead of a stationary equivalent. Locally Weighted Regression (LWR) is proposed as a suitable choice. This method can be extended to predict the binary presence or absence of erosion based on a series of independent local variables by using the logistic regression model. It is referred to as Locally Weighted Logistic Regression (LWLR). Logistic regression is a type of regression analysis used for predicting the outcome of a categorical dependent variable (e.g. binary response) based on one or more predictor variables. The method can be combined with LWR to assign weights to local independent variables of the dependent one. LWR allows model parameters to vary over space in order to reflect spatial heterogeneity. The probabilities of the possible outcomes are modelled as a function of the independent variables using a logistic function. Logistic regression measures the relationship between a categorical dependent variable and, usually, one or several continuous independent variables by converting the dependent variable to probability scores. Then, a logistic regression is formed, which predicts success or failure of a given binary variable (e.g. erosion presence or absence) for any value of the independent variables. The erosion occurrence probability can be calculated in conjunction with the model deviance regarding the independent variables tested. The most straightforward measure for goodness of fit is the G statistic. It is a simple and effective way to study and evaluate the Logistic Regression model efficiency and the reliability of each independent variable. The developed statistical model is applied to the Koiliaris River Basin on the island of Crete, Greece. Two datasets of river bank slope, river cross-section width and indications of erosion were available for the analysis (12 and 8 locations). Two different types of spatial dependence functions, exponential and tricubic, were examined to determine the local spatial dependence of the independent variables at the measurement locations. The results show a significant improvement when the tricubic function is applied as the erosion probability is accurately predicted at all eight validation locations. Results for the model deviance show that cross-section width is more important than bank slope in the estimation of erosion probability along the Koiliaris riverbanks. The proposed statistical model is a useful tool that quantifies the erosion probability along the riverbanks and can be used to assist managing erosion and flooding events. Acknowledgements This work is part of an on-going THALES project (CYBERSENSORS - High Frequency Monitoring System for Integrated Water Resources Management of Rivers). The project has been co-financed by the European Union (European Social Fund - ESF) and Greek national funds through the Operational Program "Education and Lifelong Learning" of the National Strategic Reference Framework (NSRF) - Research Funding Program: THALES. Investing in knowledge society through the European Social Fund.
P. Gillette; C. Haquin; E. Lķcorchķ; D. Touchard; J. F. Denis; F. Gougnaud; J. F. Gournay; Y. Lussignol; P. Mattei; J. Hosselet; C. Maazouzi; C. Olivetto
The Spiral2 project consists of a new facility to provide high intensity rare ions beams. It is based on a primary beam driver accelerator (RFQ followed by a superconducting linac) and a rare ion production process delivering the beam either to a low energy experimental area or to the existing Ganil facility. From October this year, one ion source coupled
Skills Conversion Project, Chapter 8, Pollution Control. Final Report.
ERIC Educational Resources Information Center
National Society of Professional Engineers, Washington, DC.
The Skills Conversion Project conducted by the National Society of Professional Engineers sought to study the transition mechanisms required to transfer available technical manpower from aerospace and defense industries into other areas of employment in private industry and public service. Fourteen study teams assessed the likelihood of futureģ
N. P. Woodruff; F. H. Siddoway
ABSTRACT The amount of erosion, E, expressed in tons per acre per annum, that will occur from a given agricultural field can be expressed in terms of equivalent variables as: E = , is field length along the prevailing wind erosion direction, and V is equivalent quantity of vegetative cover. The 5 equivalent variables are obtained,by grouping,some,and,converting,others of the,11 primary
Cavitation erosion behaviour of niobium
S. F. Brunatto; A. N. Allenstein; C. L. M. Allenstein; A. J. A. Buschinelli
Cavitation erosion behaviour of niobium was investigated by means of a 20kHz ultrasonic vibrator at peak-to-peak amplitude of 50?m, aiming to determine the niobium potential as a material for the manufacturing of hydraulic machine components. The study was emphasized for the three first cavitation stages of the cumulative erosion¢time curve. The modification of the niobium surface morphology as a function
CRC handbook of coastal processes and erosion
Komar, P.D.
This text includes the following contents: Beach Processes - Erosion - An Introduction. Edge Waves and the Configuration of the Shoreline. Morphodynamics of Beaches and Surf Zones in Australia. The Erosion of Siletz Spit, Oregon. Barrier Islands. Patterns and Prediction of Shoreline Change. Models for Beach Profile Response. Erosion on the Great Lakes Due to Changes in the Water Level. Coastal Erosion in Response to the Construction of Jetties and Breakwaters. Computer Models of Shoreline Changes. Principles of Beach Nourishment. Processes of Sea Cliff and Platform Erosion. Beach Processes and Sea Cliff Erosion in San Diego County, California. Erosion of the United States Shoreline. Index.
Climate Change Effects on the Sacramento Basin's Flood Control Projects ANN DENISE FISSEKIS
Lund, Jay R.
Climate Change Effects on the Sacramento Basin's Flood Control Projects By ANN DENISE FISSEKIS B of Climate Change on Storms...............................................33 Effects of Climate Change Appendix A: Climate Change Scenario Effects on New Bullards Bar................73 Appendix B: Climate
Special projects undertaken by the Air Pollution Technology Branch of NRMRL's Air Pollution Prevention and Control Division in Research Triangle Park, NC, include the Orimulsion Research Study, Real-Time Monitoring of Dioxins and Other Trace Organics, and Environmental Technology...
NASA Astrophysics Data System (ADS)
Herman, Frķdķric; Beyssac, Olivier; Lane, Stuart; Brughelli, Mattia; Leprince, Sebastien; Brun, Fanny
Most mountain ranges on Earth owe their morphology to the action of glaciers and icecaps over the last few million years. Our current understanding of how glaciers have modified mountainous landforms has mainly been driven through landscape evolution models. These have included an array of erosion laws and mainly progressed through the implementation of various levels of sophistication regarding ice dynamics, subglacial hydrology or thermodynamics of water flow. However, the complex nature of the erosion processes involved and the difficulty of directly examining the ice-bedrock interface of contemporary glaciers has precluded the establishment of a prevailing erosion theory. Here we quantify the spatial variations in ice sliding velocity and erosion rate of a fast-flowing Alpine glacier in New Zealand during a 5-month period. By combining high resolution 3D measurements of surface velocity from optical satellite imagery with the quantification of both the production and provenance of sediments by the glacier, we show that erosion rates are proportional to sliding velocity raised to a power of about two. This result is consistent with abrasion theory. Given that the ice sliding velocity is a nonlinear function of ice thickness and ice surface slope, the response of glacial erosion to precipitation changes is highly nonlinear. Finally, our ability to constrain the glacial abrasion law present opportunities to further examine the interaction between glaciation and mountain evolution.
Ontology-based intelligent decision support agent for CMMI project monitoring and control
Chang-shing Lee; Mei-hui Wang; Jui-jen Chen
This paper presents an ontology-based intelligent decision support agent (OIDSA) to apply to project monitoring and control of capability maturity model integration (CMMI). The OIDSA is composed of a natural language processing agent, a fuzzy inference agent, and a performance decision support agent. All the needed information of the OIDSA, including the CMMI ontology and the project personal ontology, is
Optimal timing control in game modeling of an energy project infrastructure
Andrey A. Krasovskii; Ivan V. Matrosov; Alexander M. Tarasyev
The purpose of this paper is to study an optimal infrastructure of a system of international gas pipelines competing for a gas market. We suggest a game-dynamic model of the operation of several interacting gas pipeline projects treated as players in the game. The model treats the projectsÆ commercialization times as major playersÆ controls. Current quantities of gas supply are
Exploiting cryptography for privacy-enhanced access control: A result of the PRIME Project
Claudio Agostino Ardagna; Jan Camenisch; Markulf Kohlweiss; Ronald Leenes; Gregory Neven; Bart Priem; Pierangela Samarati; Dieter Sommer; Mario Verdicchio
We conduct more and more of our daily interactions over electronic me- dia. The EC-funded project PRIME (Privacy and Identity Management for Europe) envisions that individuals will be able to interact in this information society in a secure and safe way while retaining control of their privacy. The project had set out to prove that existing privacy-enhancing technologies allow for
Projective and lag synchronization of a novel hyperchaotic system via impulsive control
NASA Astrophysics Data System (ADS)
Chen, Juan; Liu, Hui; Lu, Jun-an; Zhang, Qunjiao
Recently, Yang, Zhang, and Chen (2009) have proposed a novel hyperchaotic system. This paper studies the projective and lag synchronization of this novel hyperchaotic system using an impulsive control technique. Some sufficient conditions of projective and lag synchronization of such new system are derived from strict mathematical theories. Numerical examples are worked through for illustrating the main results.
Integrated computer control system CORBA-based simulator FY98 LDRD project final summary report
R M Bryant; F W Holloway; P J Van Arsdall
The CORBA-based Simulator was a Laboratory Directed Research and Development (LDRD) project that applied simulation techniques to explore critical questions about distributed control architecture. The simulator project used a three-prong approach comprised of a study of object-oriented distribution tools, computer network modeling, and simulation of key control system scenarios. This summary report highlights the findings of the team and provides
Attitude and articulation control solutions for Project Galileo
NASA Technical Reports Server (NTRS)
Rasmussen, R. D.; Brown, T. K.
Design problems and the solutions adopted for them in the attitude and articulation control subsystem for the Galileo spacecraft are discussed as an illustration of the application of dual-spin control to an interplanetary spacecraft. Following a review of the baseline design of the Galileo system and mission, consideration is given to problems encountered in the areas of autonomous attitude determination, attitude control, spacecraft dynamics and software margins. Design issues raised by subsequent changes in spacecraft configuration are also indicated. It is pointed out that although difficulties associated with control system complexity in a dual-spin interplanetary spacecraft have been satisfactorily resolved for the Galileo mission, the future application of dual spin in interplanetary flight is in doubt.
Glacier Erosion and Response to Climate in Chilean Patagonia
NASA Astrophysics Data System (ADS)
Koppes, M.; Hallet, B.; Stewart, R.
A vibrant dimension in current research on landscape evolution is the potential impact of climate change on erosion rates due to differences in efficiency of glacial and non-glacial erosion processes. The climate-sensitive rate and spatial distribution of erosion can be as important as the tectonic environment in determining the development of mountain ranges. To evaluate properly how glacial erosion influences orogenic processes and reflects climate variability, it is necessary to understand how ice dynamics control erosion rates. The Patagonian Andes are a unique laboratory for documenting glacial erosion in a range of precipitation and thermal regimes, as zonal atmospheric circulation in the region creates strong latitudinal gradients. We will present relevant findings from two tidewater glaciers in Chilean Patagonia: San Rafael glacier, which drains the northern portion of the North Patagonian Icefield (46.6S, 74W), and Marinelli glacier, the largest glacier in the Cordillera Darwin of Tierra del Fuego (54.6S, 69W). Both glaciers have been in steady retreat during the latter half of the 20th century, and both calve into a fjord or lagoon, which provides an efficient trap for the sediment eroded by the glacier and deposited at the calving front. The reconstructed flux of ice into the glaciers is compared to the retreat of the ice fronts and to the sediment flux to examine the influence of ice dynamics on the rate of glacier erosion. NCEP-NCAR Reanalysis climate data, adjusted to local conditions by correlation with automatic weather stations installed at the glacier termini and coupled to a model of orographic enhancement of precipitation over the glacier basin, were used to reconstruct the daily precipitation input into and ablation output from the glaciers during the last 50 years. The sediment flux out of the glaciers during this period was calculated from acoustic reflection profiles of the sediments accumulated in the proglacial fjords, and used to infer erosion rates. Preliminary results indicate 1) that high rates of retreat of the ice front occur during years in which the total input of snow into the glacier is balanced by the total ablation, and hence the residual flux of ice at the terminus is insufficient to compensate for the calving, and 2) that the highest basin- wide erosion rates reflect years in which total ice accumulation is lower and retreat rates are high. Interestingly, basin-wide erosion rates from these glaciers are up to an order of magnitude higher than long- term exhumation rates derived from detrital apatite thermochronometry in the basins, indicating that current rates of erosion far exceed long-term rates, and are reflective of periods of warming climate and enhanced glacial retreat.
An Economic Analysis of Erosion and Sediment Damage in the Lower Running Draw Watershed
Reneau, D. R.; Taylor, C. R.; Harris, B. L.; Lacewell, R. D.; Mueller, P. E.
of a study on the economic impact of implementing potential agricultural NPS pollution controls in Lower Running Water Draw watershed. The study focuses on: (a) the effects of erosion control on farm income, (b) off-site sediment damages...
An Economic Analysis of Erosion and Sedimentation in Lavon Reservoir WatershedĀ
Taylor, C. R.; Reneau, D. R.; Harris, B. L.
potential agricultural NPS pollution controls in the watershed above Lavon Reservoir. The study focuses on: (a) effects of erosion controls on farm income, (b) off-side sediment damages in the watersheds; (c) costs of administering and enforcing alternative...
An Economic Analysis of Erosion and Sediment Damage in the Lower Running Draw WatershedĀ
Reneau, D. R.; Taylor, C. R.; Harris, B. L.; Lacewell, R. D.; Mueller, P. E.
of a study on the economic impact of implementing potential agricultural NPS pollution controls in Lower Running Water Draw watershed. The study focuses on: (a) the effects of erosion control on farm income, (b) off-site sediment damages...
Combating dephasing decoherence by periodically performing tracking control and projective measurement
Zhang Ming [College of Mechatronics and Automation, National University of Defense Technology, Changsha, 410073 (China); Key Laboratory of Systems and Control, Chinese Academy of Sciences, Beijing, 100080 (China); Dai Hongyi [College of Science, National University of Defense Technology, Changsha, 410073 (China); Xi Zairong [Key Laboratory of Systems and Control, Chinese Academy of Sciences, Beijing, 100080 (China); Xie Hongwei; Hu Dewen [College of Mechatronics and Automation, National University of Defense Technology, Changsha, 410073 (China)
We propose a scheme to overcome phase damping decoherence by periodically performing open loop tracking control and projective measurement. Although it is impossible to stabilize a qubit subject to Markovian dynamics only by open loop coherent control, one can attain a 'softened' control goal with the help of periodical projective measurement. The 'softened' control objective in our scheme is to keep the state of the controlled qubit to stay near a reference pure state with a high probability for a sufficiently long time. Two suboptimal control problems are given in the sense of trace distance and fidelity, respectively, and they are eventually reduced to the design of a period T. In our scheme, one can choose the period T as long as possible if the 'softened' control goal is attained. This is in contrast to the observation that quantum Zeno effect takes place only if measurements are performed in a very frequent manner, i.e., the period T must be extremely small.
Public Information Campaign: Soil Erosion, Conservation, and Watershed Health
NSDL National Science Digital Library
Kathryn Szramek
Students in groups of two create a 4-minute educational video, brochure, and poster on an aspect of soil erosion, soil conservation, and/or watershed health for agricultural regions within the midwestern states. This is a half term project and the materials are presented in a forum towards the end of the semester. The project is aimed to help students learn to pitch science to a wide audience and provide practice (indirectly) applying scientific principles to conservation efforts.
Human induced prehistoric and historical soil erosion and landscape development in Southwestern USA
NASA Astrophysics Data System (ADS)
Dotterweich, Markus; Ivester, Andrew H.; Hanson, Paul R.; Daniel, Larsen; Dye, David H.; Foster, Thomas H., II
The significance of soil erosion due to pre-historic land use and possible feedback mechanisms had been hardly recognized in the Southeastern USA. Here, the agricultural practices only began in the second half of the Holocene. Sedentary hunters and gatherers started to domesticate squash and sunflowers. Associated with the expansion of maize cultivation in the Mississippian period between AD 800 and 1100, significant forest clearings took place on the river floodplains. During this time, central settlements with up to 30,000 residences existed and the surrounding ridge and furrow fields extended to up to 30 ha. It is still open to question why these groups already declined in the 14/15th centuries already before the arrival of the Europeans. However, around AD 1540 the conquistador de Soto still reports extended fields with intensive cultivation of maize in the uplands of Northern Mississippi. Despite of this intensive land use by Native Americans, current research gives no indication that these activities had any significant impact on river channel form. Also, no clear evidence exists for distinct channel change occurring in response to any sort of middle Holocene Hypsithermal, Medieval warm period, or the Little Ice Age. We will present results of a project which aims to explore erosion forms, colluvial sediments and buried soils in selected 0-order and 1st-order watersheds in the southeastern USA in order to gain, solidify, and evaluate general data on soil erosion during the Native American land use period and its respective long-term effects on the environment. This will be achieved by 1) recording the stratigraphy of colluvial and alluvial sediments and buried soils, 2) mapping the extent of erosional and colluvial forms, 3) analyzing chemical and physical soil and sediment properties, 4) establishing chronological control using various dating techniques including radiocarbon and OSL dating, and 5) quantifying soil erosion using hillslope sediments. The gathered data will be used to i) compare the spatial extent of prehistoric and historic erosion and the short-term and long-term pedological and geomorphological effects of subtle soil erosion against extreme events, ii) assess the feedback-mechanisms of soil erosion on soil fertility and measurable land use changes in prehistorical and historical times, and (iii) estimate the long term effects of soil erosion and sediment deposition on archaeological features. The outcome will provide a decisive step forward to gather new qualitative and quantitative information on soil erosion during the Native American land use period to be able to achieve a better understanding of the long-term human induced landscape evolution in the uplands of the Southeastern USA and deliver data for a better predicting of landscape evolution to future climatic shifts in precipitation regimes.
Carbon Erosion in the Great Karoo Region of South Africa
NASA Astrophysics Data System (ADS)
Krenz, Juliane; Greenwood, Philip; Kuhn, Brigitte; Foster, Ian; Boardman, John; Meadows, Mike; Kuhn, Nikolaus
Work undertaken in the seasonally arid upland areas of the Great Karoo region of South Africa has established a link between land degradation and overgrazing which began in the second half of the 18th century when European farmers first settled the area. Ongoing land use change and shifting rainfall patterns resulted in the development of badlands on foot slopes of upland areas, and gully systems on valley bottoms. As a consequence of agricultural intensification and overgrazing, accompanied by a higher water demand, many small reservoirs were constructed, most of which are now in-filled with sediment. The deposited material serves as an environmental archive by which land use change over the last 100 years can be analysed, but with a particular focus on erosion and deposition of soil-associated carbon (C). It is assumed that erosion caused an initial flush of carbon rich soil which was subsequently buried and stored off-site. Despite this assumption, however the net-effect of erosion on carbon dioxide emissions is still unknown. In this project, preliminary results are presented from an investigation to determine whether land degradation in the Karoo has resulted in a shift from a net sink of C to a net source of C. Firstly, a high resolution digital elevation model was generated and erosion modelling was then employed to create an erosion risk map showing areas most prone to erosion. Information from the model output then served as the basis for ground-truthing and on-site erosion mapping. Secondly, sediment deposits from silted reservoirs were analysed for varying physicochemical parameters, in order to reconstruct spatial patterns of erosion and deposition. Analysis of total carbon (TC) content revealed a sharp decrease with decreasing depth. This provisionally suggests that land degradation during and after post-European settlement probably led to accelerated erosion of the relatively fertile surface soils. This presumably resulted in the rapid in-filling of many reservoirs with carbon-rich surface material seen today. The decline of C sinks in degraded rangelands here and possibly elsewhere raises the question whether past soil erosion may have had a greater attenuating effect on GHG emissions than modeled scenarios of present emissions suggest.
Market-based collaborative control of distributed multiple product development projects
NASA Astrophysics Data System (ADS)
Lee, Yonghan; Kumara, Soundar R. T.
Due to the widespread availability of the Internet large scale distributed projects in manufacturing are becoming popular. We present a distributed, collaborative, and adaptive control approach for distributed multiple product development projects (DMPDP), which is a representative project environment in modern e-enterprises. In DMPDP environment, multiple project groups share and compete for limited resources to achieve their own goals. On the other hand, the shared resource divisions try to utilize their resources efficiently. We suggest that this kind of situation can be well modeled and efficiently solved by using two novel approaches: multiagent based information infrastructure and market-based control mechanism. In this paper, we formalize the DMPDP control problem, and propose a market-based negotiation mechanism called sequential market clearing (SMC) protocol. For clear presentation, some of information system design and implementation issues are also presented.
Laboratory Projects in Developing Inexpensive Control System Experiments
, but if you do that add some interesting disturbances (e.g., a half-filled bottle of water at the pendulum tip in each case? What type of motor should be used? DC motor? Stepper motor? For each case how expensive another source). Controlling water level would likely be a convenient approach. What actuator should
Fuzzy discriminant analysis based feature projection in myoelectric control
Rami N. Khushaba; Adel Al-Jumaily; Ahmed Al-Ani
The myoelectric signal (MES) from human muscles is usually utilized as an input to the controller of a multifunction prosthetic hand. In such a system, a pattern recognition approach is usually employed to discriminate between the MES from different classes. Since the MES is recorded using multi channels, the feature vector size can become very large. In order to reduce
Voice Controlled Retrieval System EECS 452: Senior Design Project
Hero, Alfred O.
for robotic aid system for the disabled and elderly. The concept is that the user will command the robot to retrieve an object via voice command, and the robot will autonomously navigate its current environment returning the desired object to the user. Our system includes: Ę Remote controlled tank as the robot
Bondugula, Srikant
progress and progress measurements. The controller is then formulated for iteratively calculating the optimal resource allocation schedule that minimizes either the EAC or both the EAC and EDAC together using the evolutionary optimization algorithm...
Controlled landfill project: Mountain View, California. Annual report, January-December 1982
T. A. Bonham; R. E. Van Heuit; W. M. Carroll; M. Donch
This project studied the effects of leachate recirculation and added water, buffer and sludge on enhancing the generation and improving the recovery of landfill gas. It evaluated the various techniques by providing individual control cells for the demonstration of enhancement methods. The study also documents landfill gas productions from a controlled volume at field scale. Results from this study provide
Evaluation of the USDA Northeast Area-wide Tick Control Project by Meta-analysis
Technology Transfer Automated Retrieval System (TEKTRAN)
As part of the Northeast Area-wide Tick Control Project (NEATCP), meta-analyses were performed using pooled data on the extent of tick-vector control achieved through seven concurrent studies, conducted within five states, using USDA æ4-PosterÆ devices to deliver targeted-acaricide to white-tailed d...
Teaching about Hazard Identification and Injury Control: A Student-Based Project Focusing on Pedestrian Safety.
ERIC Educational Resources Information Center
Wojtowicz, G. Greg; DesLauriers, Karen
Students learn to practice safe behavior most effectively when they are actively involved in the process of identifying and controlling hazards. This article focuses on a problem faced by many urban-based schools--pedestrian safety. Hazard identification projects can be used to train students to develop practical, effective hazard controls. Theģ
The United States Department of Agriculture northeast area-wide tick control project - history and protocol
Technology Transfer Automated Retrieval System (TEKTRAN)
This manuscript summarizes the history of development of the ARS-patented æ4-PosterÆ Deer Treatment Bait Station technology for the control of ticks feeding on white-tailed deer and other wild ungulates, provides the rationale for its use in the USDA Northeast Area-wide Tick Control Project, and des...
Function Projective Synchronization of Chaotic Systems via Nonlinear Adaptive-Impulsive Control
NASA Astrophysics Data System (ADS)
Wu, Ranchao; Cao, Dongxu
In this paper, function projective synchronization of chaotic systems is investigated through nonlinear adaptive-impulsive control. To achieve synchronization, suitable nonlinear continuous and impulsive controllers are designed, according to invariant principle of impulsive dynamical systems. Sufficient conditions are given to ensure the synchronization. Numerical simulation results show the effectiveness of the proposed scheme.
Kato, Melissa Thiemi; MagalhŃes, Ana Carolina; Rios, Daniela; Hannas, Angķlica Reis; Attin, Thomas; Buzalaf, MarĒlia Afonso Rabelo
Objective: This in situ study evaluated the protective effect of green tea on dentin erosion (ERO) and erosion-abrasion (ABR). Material and methods: Ten volunteers wore intraoral palatal appliances with bovine dentin specimens subjected to ERO or ERO + toothbrushing abrasion performed immediately (ERO+I-ABR) or 30 min after erosion (ERO+30-min-ABR). During 2 experimental 5-day crossover phases, the volunteers rinsed with green tea or water (control, 1 min) between each erosive (5 min, cola drink) and abrasive challenge (30 s, toothbrushing), 4x/day. Dentin wear was measured by profilometry. Results: The green tea reduced the dentin wear significantly for all conditions compared to control. ERO+I-ABR led to significantly higher wear than ERO, but it was not significantly different from ERO+30-min-ABR. ERO+30-min-ABR provoked significant higher wear than ERO, only for the placebo treatment. Conclusions: From the results of the present study, it may be concluded that green tea reduces the dentin wear under erosive/abrasive conditions. PMID:20027426
Controlling Spin-Spin Network Dynamics by Repeated Projective Measurements
NASA Astrophysics Data System (ADS)
Bretschneider, Christian O.; ┴lvarez, Gonzalo A.; Kurizki, Gershon; Frydman, Lucio
We show that coupled-spin network manipulations can be made highly effective by repeated projections of the evolving quantum states onto diagonal density-matrix states (populations). As opposed to the intricately crafted pulse trains that are often used to fine-tune a complex networkÆs evolution, the strategy hereby presented derives from the ōquantum Zeno effectö and provides a highly robust route to guide the evolution by destroying all unwanted correlations (coherences). We exploit these effects by showing that a relaxationlike behavior is endowed to polarization transfers occurring within a N-spin coupled network. Experimental implementations yield coupling constant determinations for complex spin-coupling topologies, as demonstrated within the field of liquid-state nuclear magnetic resonance.
The Adjustment of the Blue Nile Geodetic Control Project
Wallace H. Blackwell
The adjustment of the Ethiopian survey data was performed by methods developed and in current use by the U.S. Coast and Geodetic Survey. The basic level network furnished control for a least-squares solution of reciprocal zenith distance observations, after which a least- squares adjustment of the horizontal directions was made. Laplace azimuths and invar-taped bases were held fixed. Tellurometer lengths
Instrumentation and control standardization in the ITER project
J. Y. Journeaux; D. Joonekindt; W. D. Klotz; P. Mõkijõrvi; A. Wallander; I. Yonekawa
The ITER instrumentation and control (I&C) system is the term encompassing all hardware and software required to operate ITER. It has two levels of hierarchy: the central I&C systems and the plant systems I&C. The plant systems I&C consists of thousands of computers processing hundreds of thousands of signals. The plant systems I&C, being the hardware interfacing layer for operating
Cotton-based hydromulches versus conventional hydromulches and blankets: Erosion and grass establishment
Technology Transfer Automated Retrieval System (TEKTRAN)
One commonly used means of reducing the impact of erosion from steep slopes while vegetation is being established is with erosion control products such as roll-out blankets and/or hydromulches. Roll-out blankets are commonly made of wheat straw, coconut husks, or fiberized wood, while the most preva...
Pore water effects on soil erodibility and its implication in ephemeral gully erosion modeling
Technology Transfer Automated Retrieval System (TEKTRAN)
Ephemeral gully erosion is the main source of sediment from the agricultural landscape, unfortunately, it has been overlooked in traditional soil erosion assessment. Field observations, and subsequent support from controlled lab experiments, have shown the linkage between transient soil hydraulic co...
Composite Erosion by Computational Simulation
NASA Technical Reports Server (NTRS)
Chamis, Christos C.
Composite degradation is evaluated by computational simulation when the erosion degradation occurs on a ply-by-ply basis and the degrading medium (device) is normal to the ply. The computational simulation is performed by a multi factor interaction model and by a multi scale and multi physics available computer code. The erosion process degrades both the fiber and the matrix simultaneously in the same slice (ply). Both the fiber volume ratio and the matrix volume ratio approach zero while the void volume ratio increases as the ply degrades. The multi factor interaction model simulates the erosion degradation, provided that the exponents and factor ratios are selected judiciously. Results obtained by the computational composite mechanics show that most composite characterization properties degrade monotonically and approach "zero" as the ply degrades completely.
Inverting the Pendulum Using Fuzzy Control (Center Director's Discretionary Fund (Project 93-02)
NASA Technical Reports Server (NTRS)
Kissel, R. R.; Sutherland, W. T.
A single pendulum was simulated in software and then built on a rotary base. A fuzzy controller was used to show its advantages as a nonlinear controller since bringing the pendulum inverted is extremely nonlinear. The controller was implemented in a Motorola 6811 microcontroller. A double pendulum was simulated and fuzzy control was used to hold it in a vertical position. The double pendulum was not built into hardware for lack of time. This project was for training and to show advantages of fuzzy control.
A Manual of Mosquito Control Projects and Committee Assignments for 4-H and Scouts Biology Class Projects, Organized Community Service Programs, and Individuals Interested in Environmental Management.
ERIC Educational Resources Information Center
Hart, Richard A.
The mosquito control projects presented in this manual were prepared from an educational viewpoint and are intended for use by students in 4-H and Scouts and as a supplement to high school and college biology course work. The major emphasis of the projects is on integrated pest management, an approach utilizing cost-effective control methods whichģ
Hexapartite safeguards project team 3: material accounting and control questionnaire
Swindle, D.W. Jr.
Information provided in this report reflects the current design and operating procedures for the GCEP. However, since the installation is currently under construction, facility design and operating procedures discussed in this report are subject to change. Where applicable, the responses are based on material control and accounting practices of the Portsmouth Gaseous Diffusion Plant's (GDP) operating contractor (Goodyear Atomic Corporation). These practices meet US Department of Energy (DOE) standards and are assumed to be the reference practices for the GCEP. This report covers data collection and record keeping actions of the operator.
National Ignition Facility Project Completion and Control System Status
Van Arsdall, P J; Azevedo, S G; Beeler, R G; Bryant, R M; Carey, R W; Demaret, R D; Fisher, J M; Frazier, T M; Lagin, L J; Ludwigsen, A P; Marshall, C D; Mathisen, D G; Reed, R K
The National Ignition Facility (NIF) is the world's largest and most energetic laser experimental system providing a scientific center to study inertial confinement fusion (ICF) and matter at extreme energy densities and pressures. Completed in 2009, NIF is a stadium-sized facility containing a 1.8-MJ, 500-TW 192-beam ultraviolet laser and target chamber. A cryogenic tritium target system and suite of optical, X-ray and nuclear diagnostics will support experiments in a strategy to achieve fusion ignition starting in 2010. Automatic control of NIF is performed by the large-scale Integrated Computer Control System (ICCS), which is implemented by 2 MSLOC of Java and Ada running on 1300 front-end processors and servers. The ICCS framework uses CORBA distribution for interoperation between heterogeneous languages and computers. Laser setup is guided by a physics model and shots are coordinated by data-driven distributed workflow engines. The NIF information system includes operational tools and a peta-scale repository for provisioning experimental results. This paper discusses results achieved and the effort now underway to conduct full-scale operations and prepare for ignition.
Design of a semi-autonomous boat for measurements of coastal sedimentation and erosion
NASA Astrophysics Data System (ADS)
Smith, D.; Cross, L.; Rivet, J.; Hall, S.
Measurement of sediment deposition and erosion in coastal areas is a challenge due to soft shifting sediments, but is critical to assessing loss or restoration of coastal sediments and wetlands. The aim of this project was to design and construct a semi-autonomous boat with water depth measuring capabilities. It was intended to map the depth of coastal wetlands to determine erosion rates and assess coastal restoration effects. Depth-measuring equipment was incorporated into an autonomous pontoon boat powered by solar panels. The propulsion system consisted of two paddlewheels and two-way motors to allow movement and positioning for measurements. Modifications included a lightweight, hard coating on the pontoons and powder-coating the frame to extend their usable life. A microcontroller controlled the boat and captured depth data from sensors and location data with a GPS system. The depth measuring system consisted of a pulley and counter system that completed each measurement in less than 45 seconds. This allowed the boat to take approximately 400 measurements per day. Net accuracy was approximately 3 cm in the tested configuration. The boat can continually measure the depth of specified areas in the wetlands; with this data, the change in depth can be monitored to see the effects of restoration projects.
Near-Bank Flow and Flood Induced Bank Erosion Processes Revealed by Application of Advanced Acoustic Techniques on a Mega-River
NASA Astrophysics Data System (ADS)
Leyland, J.; Parsons, D. R.; Darby, S. E.; Hackney, C. R.; Best, J.; Aalto, R. E.; Nicholas, A. P.
Bank erosion processes are a key component of river morphodynamics, controlling rates of channel shift and ultimately governing floodplain system dynamics and sedimentology. Near-bank flow fields and the interactions of turbulent fluid flows in the near-bank zone with mechanisms of bank failure and erosion styles are presently poorly understood. Recent research has suggested that bank erosion and the type of failure mechanism can play an important role in protecting the bank toe from further erosion, notably through increased near-bank roughness and the resultant reduction in near-bank flow velocity and shear stress. An improved understanding of these interactive near-bank processes is essential if we are to improve our ability to predict bank erosion and channel morphodynamics. In this study we present a series of high-resolution multibeam sonar repeat near-bank surveys and acoustic Doppler profiles (acquired as part of the NERC funded STELAR-S2S project: www.stelar-s2s.org), from the monsoonal Mekong River in SE Asia. These data are the first to simultaneously capture detailed bank topography and near-bank flow processes of a mega-river during high flow conditions. Data is presented from a range of channel morphologies and includes a variety of geotechnical bank failure styles. The results show how systematic quantification of bank roughness over bank lengths of several channel widths can be used to quantify hydraulic roughness and how such information can be used to parameterise bank erosion models. Furthermore, the evolution and role of slumped material at the bank toe is also examined during the monsoonal flood. The methods, estimates of error and implications of the results for the morphodynamic function of large river systems will be discussed.
A test bed for the future access control system the AD Project
Scibile, L
This paper describes the design, management and development of the new access control system for the Antiproton Deceleration experimental area, called the AD Project. As this project includes all the elements for the industrial evolution of the present access control system it is an ideal test bed for future access systems. The adoption of new technologies and techniques are described, and the benefits and the shortfalls are highlighted. The open redundant architecture solution, based on a PROFIBUS network and standard industrial components (HP-UNIX, Siemens S7 PLC, Siemens Industrial PC, door locks), guarantees reliability, safety and optimal integration. The project team took advantage of the Goal Directed Project Management technique and managed to define a clear and effective strategy.
Rainfall erosivity in New Zealand
NASA Astrophysics Data System (ADS)
Klik, Andreas; Haas, Kathrin; Dvorackova, Anna; Fuller, Ian
Rainfall and its kinetic energy expressed by the rainfall erosivity is the main driver of soil erosion processes by water. The Rainfall-Runoff Erosivity Factor (R) of the Revised Universal Soil Loss Equation is one oft he most widely used parameters describing rainfall erosivity. This factor includes the cumulative effects of the many moderate-sized storms as well as the effects oft he occasional severe ones: R quantifies the effect of raindrop impact and reflects the amopunt and rate of runoff associated with the rain. New Zealand is geologically young and not comparable with any other country in the world. Inordinately high rainfall and strong prevailing winds are New Zealand's dominant climatic features. Annual rainfall up to 15000 mm, steep slopes, small catchments and earthquakes are the perfect basis for a high rate of natural and accelerated erosion. Due to the multifacted landscape of New Zealand its location as island between the Pacific and the Tasmanian Sea there is a high gradient in precipitation between North and South Island as well as between West and East Coast. The objective of this study was to determine the R-factor for the different climatic regions in New Zealand, in order to create a rainfall erosivity map. We used rainfall data (breakpoint data in 10-min intervals) from 34 gauging stations for the calcuation of the rainfall erosivity. 15 stations were located on the North Island and 19 stations on the South Island. From these stations, a total of 397 station years with 12710 rainstorms were analyzed. The kinetic energy for each rainfall event was calculated based on the equation by Brown and Foster (1987), using the breakpoint precipitation data for each storm. On average, a mean annual precipitation of 1357 mm was obtained from the 15 observed stations on the North Island. Rainfall distribution throughout the year is relatively even with 22-24% of annual rainfall occurring in spring , fall and winter and 31% in summer. On the South Island the mean annual rainfall amounts to 2027 mm and therefore is higher than on the North Island. A high east-to-west gradient can be seen with the lowest rainfall along the east coast and in Inland and the highest values in the Souther Alps. The temporal variation throughout the year is very low. In each season between 24 (winter) and 26% (summer) of precipitation is observed. Like the precipitation P the range of rainfall erosivity R varies greatly and is higher on the South Island than on the North Island. The results show that precipitation between 720 (Napier) and 2730 mm.a-1 (Mt. Ruapehu) delivered R-factors between 477 and 3592 MJ.mm.ha-1.h-1. For 14 stations a good regression between rainfall and R was obtained. On the South Island corresponding mean annual rainfall between of 429 and 4300 mm produces erosivities between 252 and 10850 MJ.mm.ha-1.h-1. Again lowest R-factors occur in Inland South Island around Alexandra which is also the driest region of New Zealand. Highest values are found in the Southern Alps and the West Coast between Arthur's Pass and Fjordland. Based on the erosivity calculations the nine climatic regions can be aggregated into four erosivity regions.
NASA Technical Reports Server (NTRS)
2003-01-01[figure removed for brevity, see original site] Released 20 June 2003The dissected and eroded channel observed in this THEMIS image taken of plains materials southwest of the volcano Elysium Mons shows typical erosional islands and depositional features. The interesting thing about this channel is that it appears to start out of nowhere. The MOLA context image shows that the channel originates from a fissure within the ground, whose origin is likely volcanic, but may also be related to volatile processes.Image information: VIS instrument. Latitude 19.5, Longitude 126.8 East (233.2 West). 19 meter/pixel resolution.Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.
Deposition + Erosion = Textures
NASA Technical Reports Server (NTRS)
2003-01-01[figure removed for brevity, see original site] Released 7 May 2003Toward the westernmost extent of the Medusae Fossae Formation, a 5000+ km long belt of eroding sediments, the interleaving of erosional surfaces produces dramatic textural variations. In the lower third of this image, the cross-hatched MFF layer is being stripped back from a surface that was already heavily eroded before the MFF layer was deposited. Also, note the sinuous and, in places, dendritic ridges that are either linear dunes or inverted channels.Image information: VIS instrument. Latitude -3.9, Longitude 154.1East (205.9). 19 meter/pixel resolution.Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.
Post-wildfire erosion and mass movement in British Columbia: site-scale soil changes and catchment-scale processes
NASA Astrophysics Data System (ADS)
Jordan, Peter
Following the severe 2003 wildfire season in British Columbia, a number of damaging debris flow and flood incidents occurred. Such events had not previously been documented in Canada. The British Columbia Forest Service began a process to analyse risks of post-wildfire natural hazards, including a 3-year research project to study processes in several wildfires which occurred in 2007. The research project, and associated risk analysis work, includes: - mapping of soil and vegetation burn severity; - extent and persistence of water repellency in burned areas; - monitoring the effectiveness of straw mulching treatments to reduce runoff and erosion; - rainfall simulation experiments to study overland flow generation and soil erosion; - streamflow, suspended sediment, and bedload monitoring on adjacent burned and unburned catchments; - investigation of post-wildfire debris flow events. The study area is in a moist, snow-dominated, heavily forested, mountain landscape. Runoff in this region is dominated by spring snowmelt, and by long-duration, low-intensity rainfalls. High-intensity rainfalls occur rarely, but are less dominant in the hydrologic cycle than at lower latitudes. Since the study began, no high-intensity rainfalls exceeding about the 2-year return period have occurred in the study area. The project includes measurements ranging in scale from 1 m2 plots, to small tributary catchments (50 ha), to a large catchment (26 km2). Results to date show that increases in sediment yield at the catchment scale have been barely detectable, and are less than those caused by erosion from roads used for salvage logging. Although erosion on small plots is significantly increased in severely burned areas, sediment yield measured in instrumented catchments decreases downstream, illustrating the importance of ephemeral flow pathways and intermediate storage. Sometimes debris flows are triggered by increased surface runoff in headwater areas, resulting in a very high sediment yield which is derived mainly from previously stored channel sediment. Several debris flows have occurred in one of the burned areas under study, as well as in earlier burns in the region. Most of these have occurred in steep, dissected terrain which was subject to debris flows before fire, although old logging roads were responsible for one notable event. Increased snow accumulation and more rapid snowmelt in burned areas have been responsible for some debris flows, as have autumn rain-on-snow storms. These observations suggest that engineering treatments, such as road deactivation and improved drainage control, may be at least as important as broadcast erosion control treatments for reducing risks from post-wildfire mass movement.
Task analysis of nuclear-power-plant control-room crews: project approach methodology
D. Burgy; C. Lempges; A. Miller; L. Schroeder; H. Van Cott; B. Paramore
A task analysis of nuclear-power-plant control-room crews was performed by General Physics Corporation and BioTechnology, Inc., for the Office of Nuclear Regulatory Research. The task-analysis methodology used in the project is discussed and compared to traditional task-analysis and job-analysis methods. The objective of the project was to conduct a crew task analysis that would provide data for evaluating six areas:
Modeling fluvial erosion on regional to continental scales
Alan D. Howard; William E. Dietrich; Michele A. Seidl
The fluvial system is a major concern in modeling landform evolution in response to tectonic deformation. Three stream bed types (bedrock, coarse-bed alluvial, and fine-bed alluvial) differ in factors controlling their occurrence and evolution and in appropriate modeling approaches. Spatial and temporal transitions among bed types occur in response to changes in sediment characteristics and tectonic deformation. Erosion in bedrock
A simplified close range photogrammetric technique for soil erosion assessment
Technology Transfer Automated Retrieval System (TEKTRAN)
Surface reconstruction using digital photogrammetry offers a great advantage for soil erosion research. The technology can be cumbersome for field application as it relies on the accurate measurement of control points often using a survey grade instruments. Also, even though digital photogrammetry h...
WinDAM C earthern embankment internal erosion analysis software
Technology Transfer Automated Retrieval System (TEKTRAN)
The USDA has partnered with landowners to build rural flood control dams. Overtopping and internal erosion are the causes of most dam failures. To estimate the peak discharge associated with a dam incident, the USDA-NRCS, -ARS, and Kansas State University have collaboratively developed software. ...
A unified relation for cavitation erosion
NASA Technical Reports Server (NTRS)
Veerabhadra Rao, P.; Buckley, D. H.; Matsumura, M.
A power-law relationship between the average erosion rate and cumulative erosion is presented. Data analyses from Venturi, magnetostriction, and liquid-impingement devices conform to this unified relation. A normalization technique is also suggested for prediction purposes.
The conceptual framework of the International Tobacco Control (ITC) Policy Evaluation Project
Fong, G T; Cummings, K M; Borland, R; Hastings, G; Hyland, A; Giovino, G A; Hammond, D; Thompson, M E
This paper describes the conceptual model that underlies the International Tobacco Control Policy Evaluation Project (ITC Project), whose mission is to measure the psychosocial and behavioural impact of key policies of the Framework Convention on Tobacco Control (FCTC) among adult smokers, and in some countries, among adult non?smokers and among youth. The evaluation framework utilises multiple country controls, a longitudinal design, and a pre?specified, theory?driven conceptual model to test hypotheses about the anticipated effects of specific policies. The ITC Project consists of parallel prospective cohort surveys of representative samples of adult smokers currently in nine countries (inhabited by over 45% of the world's smokers), with other countries being added in the future. Collectively, the ITC Surveys constitute the first?ever international cohort study of tobacco use. The conceptual model of the ITC Project draws on the psychosocial and health communication literature and assumes that tobacco control policies influence tobacco related behaviours through a causal chain of psychological events, with some variables more closely related to the policy itself (policy?specific variables) and other variables that are more downstream from the policy, which have been identified by health behaviour and social psychological theories as being important causal precursors of behaviour (psychosocial mediators). We discuss the objectives of the ITC Project and its potential for building the evidence base for the FCTC. PMID:16754944
Erosion wear in coal utilization
This book discusses the properties of coal mineral matter abrasion and particle impaction erosion wear in those power plants using coal. Its main thrust is to provide remedial measures for these problems, Since coal is such a soft, flow-strength material, its wear-causing characteristics depend largely on the presence of abrasive mineral species. This book conveniently examines and classifies these minerals
Ferrofluids prepared by spark erosion
NASA Astrophysics Data System (ADS)
Berkowitz, A. E.; Walter, J. L.
Spark erosion was used to prepare ferrofluids from metallic alloy particles. The particles are mostly <100 ┼ diameter and are enmeshed in the organic reaction products of the spark discharge in the organic dielectric liquid. The preparation, structural characterization and magnetic properties of these particles are discussed.
Bellman Jr., Robert; Levy, Alan
The removal of material from the surface of a ductile metal by small impacting particles is a design concern to the builders of synthetic fuels plants that utilize pulverized coal to produce gaseous forms of fuel. A series of room temperature experiments was conducted to determine the mechanism of material removal when an erosive particle stream impacts on a ductile metal surface. 1100-0 and 7075-T6 aluminum were used for the target and 600 {micro}m SiC particles moving at a velocity of 100 fps in air for the eroding stream. It was determined that a combined forging-extrusion mechanism at produces small, highly distressed platelets of tarrget material that are knocked off the surfce by succeeding particle impacts is responsible for erosion at both low and high impingement angles. The larrge strains that produce the platelets occur in a thin surface region which is heated near or to the annealing temperature of the metal as a result of adiabatic shear deformation. This hard, sub-surface layer, once formed, increases the efficiency of platelet formation at the surface and the erosion rate increases to a constant level. This propos mechanism is a significant departure from previously believed micromachining mechanism of erosion of ductile metals.
The global control of silicate weathering rates and the coupling with physical erosion: new insights from rivers of the Canadian Shield
NASA Astrophysics Data System (ADS)
Millot, Romain; Gaillardet, Jķr¶me; Duprķ, Bernard; AllĶgre, Claude Jean
The chemical evolution of the surface of the Earth is controlled by the interaction of rainwaters, the atmosphere and the continental crust. That is the main reason why the knowledge of the parameters that control chemical denudation on Earth is of crucial importance. We report chemical and isotopic analyses for river waters from the Canadian Shield in order to estimate chemical weathering fluxes. We present a comparison of the chemical composition and Sr isotopic composition of a set of rivers sampled in the Slave Province (Northwest Territories, Canada) and in the Grenville Province (Quķbec, Canada). The surface waters of these high latitude catchments are very dilute, with the Slave rivers about three times more concentrated than the Grenville rivers. A detailed analysis of the Sr isotopic composition and chemical signature of these rivers shows that silicate weathering reactions are not the only mechanisms that control solute concentrations. An atmospheric component, constituted by the dissolution of evaporite and carbonate aerosols, is necessary to explain the dispersion of chemical ratios such as Ca/Na, Mg/Na, Sr/Na and Cl/Na. These aerosols probably have a local origin. Chemical denudation rates for the Slave Province are four times lower than those found in the Grenville Province (0.35 and 1.55 tons/km 2/yr respectively). Compared to a panel of surface waters from other shield areas of the world, the Slave Province appears to have the lowest chemical denudation rate in the world. In a chemical weathering rate vs. temperature plot, shield rivers define a triangular relationship, hot climate being able to produce the most variable denudation rates. But no simple relationship between chemical weathering rates and temperature or runoff is observed, in contrast to rivers draining basaltic areas. We show that a global power law (0.66 exponent) exists between chemical denudation rates and physical denudation rates, indicating that the shield areas with low mechanical denudation (such as the Slave Province or Cameroon) have also low chemical denudation rates. These results give importance to physical denudation in determining the chemical weathering rates of silicates. We think that any further modeling on Earth's long term climate will have to take into account this fundamental coupling between mechanical and chemical weathering fluxes.
ErosionŚdiagnosis and risk factors
A. Lussi; T. Jaeggi
Dental erosion is a multifactorial condition: The interplay of chemical, biological and behavioural factors is crucial and\\u000a helps explain why some individuals exhibit more erosion than others. The erosive potential of erosive agents like acidic drinks\\u000a or foodstuffs depends on chemical factors, e.g. pH, titratable acidity, mineral content, clearance on tooth surface and on\\u000a its calcium-chelation properties. Biological factors such
Implantation and erosion of nitrogen in tungsten
NASA Astrophysics Data System (ADS)
Meisl, G.; Schmid, K.; Encke, O.; H÷schen, T.; Gao, L.; Linsmeier, Ch
Nitrogen puffing is routinely applied in nuclear fusion plasma experiments with tungsten walls to control the amount of power emitted from the plasma by radiation. However, as nitrogen is retained in significant amounts in tungsten it adds some complexity to the plasma-wall interaction. Basic questions concerning the interaction of nitrogen with tungsten, namely the energy and temperature dependent retention of nitrogen implanted into tungsten and the erosion of the formed tungsten nitride by deuterium, are still open. To address these questions, laboratory experiments with a mass-filtered ion source and sample analysis with in situ x-ray photoelectron spectroscopy (XPS) and nuclear reaction analysis were performed. The results of the implantation and erosion measurements were interpreted by means of simulations with a Monte-Carlo code describing the interaction of energetic particles with matter in the binary collision approximation. This required the development of a forward calculation, converting the simulated depth profiles into XPS intensity ratios. With appropriate settings, the experimental implantation and erosion results at ambient temperature are well described by the simulations. However, for increased temperatures it has been observed that there is an unexpected difference between implanting nitrogen into tungsten before heating the sample and implantation into a heated sample. The application of the developed forward calculation is not limited to the problems presented in this work but can be applied especially to all kind of XPS sputter-depth profiling measurements. Finally, simulations with the previously validated Monte-Carlo code are used to extrapolate the presented results on nitrogen retention to energies and particle compositions relevant for fusion experiments. These simulations make quantitative predictions on nitrogen retention in tungsten and on relevant time scales. The simulations also show that recoil implantation of nitrogen by deuterium significantly increases the effective implantation depth of nitrogen.
Farmers' identification of erosion indicators and related erosion damage in the Central Highlands of Kenya
Barrack Ouma Okoba; Geert Sterk
Most soil and water conservation planning approaches rely on empirical assessment methods and hardly consider farmers' knowledge of soil erosion processes. Farmers' knowledge of on-site erosion indicators could be useful in assessing the site-specific erosion risk before planning any conservation measures. The aims of this study were to identify erosion indicators based on the farmers' knowledge and assess relevance of
Technology Transfer Automated Retrieval System (TEKTRAN)
Determination of a practical threshold for separating erosive and non-erosive rainfall events can reduce the amount of work necessary to read rainfall charts and to calculate rainfall erosivity. The objective of this study was to develop a method of determining practical thresholds for erosive rain...
Comparison of Inconel 625 and Inconel 600 in resistance to cavitation erosion and jet impingement erosion
H. X. Hu; Y. G. Zheng; C. P. Qin
Liquid droplet erosion (LDE), which often occurs in bellows made of nickel-based alloys, threatens the security operation of the nuclear power plant. As the candidate materials of the bellows, Inconel 600 and Inconel 625 were both tested for resistance to cavitation erosion (CE) and jet impingement erosion (JIE) through vibratory cavitation equipment and a jet apparatus for erosion-corrosion. Cumulative mass
Modeling fluvial erosion on regional to continental scales
NASA Technical Reports Server (NTRS)
Howard, Alan D.; Dietrich, William E.; Seidl, Michele A.
The fluvial system is a major concern in modeling landform evolution in response to tectonic deformation. Three stream bed types (bedrock, coarse-bed alluvial, and fine-bed alluvial) differ in factors controlling their occurrence and evolution and in appropriate modeling approaches. Spatial and temporal transitions among bed types occur in response to changes in sediment characteristics and tectonic deformation. Erosion in bedrock channels depends upon the ability to scour or pluck bed material; this detachment capacity is often a power function of drainage area and gradient. Exposure of bedrock in channel beds, due to rapid downcutting or resistant rock, slows the response of headwater catchments to downstream baselevel changes. Sediment routing through alluvial channels must account for supply from slope erosion, transport rates, abrasion, and sorting. In regional landform modeling, implicit rate laws must be developed for sediment production from erosion of sub-grid-scale slopes and small channels.
Soil Erosion. LC Science Tracer Bullet.
ERIC Educational Resources Information Center
Buydos, John F., Comp.
Soil erosion is the detachment and movement of topsoil or soil material from the upper part of the soil profile. It may occur in the form of rill, gully, sheet, or wind erosion. Agents of erosion may be water, wind, glacial ice, agricultural implements, machinery, and animals. Soil conservation measures require a thorough understanding of theģ
Computer simulations and physical modelling of erosion
Franklin, W. Randolph
Computer simulations and physical modelling of erosion C.S. Stuetzle, J. Gross, Z. Chen, B. Cutler in 2 disciplines. 2 / 10 #12;Problem and goals Validation of Erosion Models for Levee Overtopping Levee terrain, a.k.a. soil, Ę better modeling of local erosion in terrain and earthen structures such as levees
Erosion Processes, Sediment Transport and Hydrological Responses Due to Land Use Changes in Serbian Ski Resorts
NASA Astrophysics Data System (ADS)
Ristic, R.; Radic, B.; Vasiljevic, N.; Nikic, Z.; Malusevic, I.
The construction or improvement of Serbian ski resorts provoked intensive erosion processes, sediment transport and hydrological responses due to land use changes, affecting the surrounding environment and even endangering the functionality of the built objects. The dominant disturbing activities (clear cuttings, trunk transport, machine grading of slopes, huge excavations, and access road construction) were followed by the activities during skiing and non skiing periods (skiing, usage of snow groomers, moving of vehicles and tourists, forestry activities and overgrazing). These activities put a lot of pressure on the environment, including the removal or compaction of the surface soil layer, the reduction of the infiltration capacity, the destruction or degradation of the vegetation cover, the intensifying of the surface runoff and the development of erosion processes. The most affected ski runs were surveyed (scale 1:1000) and all damages were mapped and classified during the summers of 2007-2010. The development of rills and gullies was measured at experimental plots (100x60 m), and the survey data were entered into a GIS application. The area sediment yield and the intensity of erosion processes were estimated on the basis of the "Erosion Potential Method"(EPM). The changes in hydrological conditions were estimated by comparing the computed values of maximal discharges in the conditions before and after massive activities in the ski resorts, as well as by using the local hydrological records. The determination of maximal discharges was achieved using a combined method: the synthetic unit hydrograph (maximum ordinate of unit runoff, qmax) and the Soil Conservation Service (SCS, 1979) methodology (deriving effective rainfall, Pe, from total precipitation, Pb). The determination was performed for AMC III (Antecedent Moisture Conditions III: high water content in the soil and significantly reduced infiltration capacity). The computations of maximal discharges were based on the regional analysis of lag time (Risti?, 2003), the internal daily distribution of precipitation (Jankovi?,1994) and the classification of soil hydrologic groups for runoff curve numbers (CN) determination (?orovi?, 1984). The applied restoration and erosion control measures have stopped the degradation processes and helped to rehabilitate the appearance and functions of the landscape. The findings of this survey highlight the importance of considering geomorphic and hydrological factors under the conditions of significant changes in land usage. The results of this investigation can contribute to the improvement of planning processes and the implementation of development projects in ski areas.
Soil coverage evolution and wind erosion risk on summer crops under contrasting tillage systems
NASA Astrophysics Data System (ADS)
Mendez, Mariano J.; Buschiazzo, Daniel E.
The effectiveness of wind erosion control by soil surface conditions and crop and weed canopy has been well studied in wind tunnel experiments. The aim of this study is to assess the combined effects of these variables under field conditions. Soil surface conditions, crop and weed coverage, plant residue, and non-erodible aggregates (NEA) were measured in the field between the fallow start and the growth period of sunflower (Helianthus annuus) and corn (Zea mays). Both crops were planted on a sandy-loam Entic Haplustoll with conventional-(CT), vertical-(VT) and no-till (NT) tillage systems. Wind erosion was estimated by means of the spreadsheet version the Revised Wind Erosion Equation and the soil coverage was measured each 15 days. Results indicated that wind erosion was mostly negligible in NT, exceeding the tolerable levels (estimated between 300 and 1400 kg ha-1 year-1 by Verheijen et al. (2009)) only in an year with high climatic erosivity. Wind erosion exceeded the tolerable levels in most cases in CT and VT, reaching values of 17,400 kg ha-1. Wind erosion was 2-10 times higher after planting of both crops than during fallows. During the fallows, the soil was mostly well covered with plant residues and NEA in CT and VT and with residues and weeds in NT. High wind erosion amounts occurring 30 days after planting in all tillage systems were produced by the destruction of coarse aggregates and the burying of plant residues during planting operations and rains. Differences in soil protection after planting were given by residues of previous crops and growing weeds. The growth of weeds 2-4 weeks after crop planting contributed to reduce wind erosion without impacting in crops yields. An accurate weeds management in semiarid lands can contribute significantly to control wind erosion. More field studies are needed in order to develop management strategies to reduce wind erosion.
Contributions and Concerns of Concentrated Flow Erosion and Assessment Technologies in Watershed Systems
NASA Astrophysics Data System (ADS)
Bingner, R. L.; Momm, H. G.; Wells, R. R.; Dabney, S. M.
Concentrated runoff increases erosion and efficiently transfers sediment and associated agrichemicals from upland areas to stream channels. Ephemeral gully erosion on cropland in the U.S. may contribute 40% of the sediment delivered to the edge of the field. Typically, conservation practices developed for sheet and rill erosion are also expected to treat ephemeral gully erosion, but technology and tools do not exist to account for the separate benefits and effects of practices on various sediment sources. Practices specifically developed to treat ephemeral gully erosion need further testing, when used in conjunction with sheet and rill erosion control practices. Without improved research studies, subjective observations will continue to be used to satisfy quality criteria in lieu of scientifically defensible, quantitative methods to estimate the impact of gully erosion. Some of the more important limiting components are the identification of and relationships for: (1) ephemeral gully width; (2) soil resistance to gully erosion including a definition for non-erosive layers; (3) the effect of root mass and above ground vegetation on erosion resistance; (4) ephemeral gully networks; and (5) the effect of subsurface flow on ephemeral gullies. Currently, these components are represented through widely divergent to non-existent algorithms. The U.S. Department of Agriculture's AnnAGNPS pollutant loading model has been developed to determine the effects of conservation management plans and provide sediment tracking from all sources within the watershed, including ephemeral gullies. Enhanced technology is also needed to identify where ephemeral gullies may form in the watershed using remote sensing technology. Developing enhanced technology and research for concentrated flow assessments is critical for developing and testing conservation practices specifically designed for gully erosion control. This study will describe the current state of concentrated flow assessment and modeling technologies and research needed to provide effective tools to conservation management planners.
Effect of wind averaging time on wind erosivity estimation
Technology Transfer Automated Retrieval System (TEKTRAN)
The Wind Erosion Prediction System (WEPS) and Revised Wind Erosion Equation (RWEQ) are widely used for estimating the wind-induced soil erosion at a field scale. Wind is the principal erosion driver in the two models. The wind erosivity, which describes the capacity of wind to cause soil erosion is ...
Modeling the erosion risk potential induced by terraces and their condition in a highly dynamic watershed close to the Three-Gorges-Dam
NASA Astrophysics Data System (ADS)
Sch÷nbrodt, S.; Behrens, T.; Imbery, S.; Scholten, T.
Globally, the Three-Gorges Ecosystem is currently one of the most anthropogenic influenced regions. Due to the Three-Gorges Dam large areas in the upper catchment of the Yangtze and its major tributaries become inundated. Consequently, high land-use dynamic with resettlements, construction of infrastructure, and new land reclamation for smallholder agriculture and cash crops characterize this area. Therefore, ecological impacts are expected in an unforeseeable dimension. Soil loss is one of the major threats and its control an enormous challenge. Even existing erosion control measures like dry-stone walling bench terraces have to be adapted to this new situation in order to keep their effectiveness. In the highly dynamic watershed of the Xiangxi, a first class tributary to the Yangtze, this study aims to assess and predict the spatial and temporal varying dam-caused soil erosion risk potential. Using a multi-level and multi-scale approach this study seeks to develop an integrative data-based methodology for soil erosion assessment by means of GIS-based erosion modeling using relevant digital terrain data, field investigations and remote sensing. The different scales considered cover the Xiangxi watershed (3.100 km▓), the highly dynamic backwater area (500 km▓), and two micro-scale study sites (3 km▓ and 88 km▓) subject to flooding and high land-use dynamic. Central features of the Xiangxi watershed are steep slopes artificially fractured by terraces. A preliminary erosion survey has shown a strong connection of the frequency and intensity of erosion and the quality of terrace-maintenance. Terraces with wall disorders and technically poor constructed design show higher soil loss and runoff than well-maintained terraces. Their condition is regarded as a driving erosion factor. Therefore, a conceptual Terrace-Condition-Erosion model (TerraCE) was developed in order to assess to what extent soil erosion depends on the quality of terraces. Central aspects are the distance to the inundated area, to the road network, and to the settlements. Four classes of terrace-maintenance are analyzed: well-maintained (20 %), badly-maintained (48 %), partially collapsed (15 %), and completely collapsed (6 %). Unterraced farmland (7 %) is regarded as an extra class. First results of TerraCE indicate that with increasing distance from the highly dynamic inundated area and the main roads the better is the quality of terrace-maintenance with less wall disorders and less soil erosion potential. It is concluded that the construction of infrastructure and the artificially fluctuating water level at the dam lead to a degradation of terraces within close distances to the Xiangxi and the main road network. Terraced farmland that is more remote to the main transportation routes seems to be less influenced by the high land-use dynamic. The mean distance of (a) well-/badly-maintainedand(b)partially-/completely collapsed terraces from the Xiangxi is(a) 613.8 m with SD 318.2 m/474.4 m with SD 291.6 m and (b) 208.6m with SD 292.1 m/127.6 m with SD 81.7 m. In average, unterraced farmland is 261.9 m (SD 286.2 m) located from the new shoreline of the Xiangxi. By combining the model results with DEM-analysis and remote sensing data a high-resolution soil erosion risk model will be computed using spatial regression approaches. It aims to assess the soil erosion as a function of natural factors and anthropogenic impacts in an increasingly complex system. Especially against the background of global change and the increasing demand for water and energy the study aims at enhancing the understanding of the ecological consequences of large dam projects.
Modelling of thruster plume induced erosion
NASA Astrophysics Data System (ADS)
Alred, John; Boeder, Paul; Mikatarian, Ron; Pankop, Courtney; Schmidl, William
One source of external induced contamination on the International Space Station (ISS) is thruster plume exhausts. The contamination from these plumes onto ISS sensitive surfaces is due to liquid drops of unreacted or partially reacted propellants. However, the drag acceleration of these particles (drops) from the exhaust gases produces high velocity (~km/s) drops that will mechanically damage surfaces in the exhaust. Previous space flight experiments on the Space Shuttle Orbiter which studied thruster plume induced contamination also demonstrated the pitting nature of these particles. The External Contamination/Plasma Team of the Boeing ISS Program Office in Houston has developed an approach to modeling the mechanical erosion on surfaces due to the impact of particles in thruster plumes. This approach melds damage simulation data from a smooth particle hydrodynamics (SPH) code from Los Alamos National Laboratory (LANL) into Boeing's own contamination computer tool (NASAN-II). The Boeing team has conducted several analyses simulating bipropellant thruster droplets impacting ISS sensitive surfaces. Computational results of various thrusters firing onto the ISS, at different build-stages, were completed and show a concern for particular solar array orientations during attitude control firings. Mitigation techniques for minimizing the erosion effects have also been determined and are presented.
Assessing Vegetation Cover Dynamics Induced by Policy-Driven Ecological Restoration and Implication to Soil Erosion in Southern China
Zhang, Jien; Wang, Tianming; Ge, Jianping
In the aftermath of the severe droughts and floods at the end of the 20th century, the Chinese government launched several ecological restoration projects, including the Natural Forest Protection Program in 1998 and the Grain-for-Green Program in 1999, to promote afforestation and reforestation to reduce surface runoff and consequent soil erosion nationwide. However, it is still unclear how vegetation has changed in southern China since the launch of these programs. In this study, we used the MODIS Enhanced Vegetation Index (EVI) to analyze the vegetation cover dynamics in southern China from 2000 to 2009 and evaluate the resulting effects of controlling soil erosion. Our observations indicate that 5.3% of the study area significantly increased and 0.98% significantly decreased in EVI value (p < 0.05). The spring EVI had largest increase in space. The conversions of croplands on steep slopes to forests resulting from national policies led to significant increases in EVI. The increase in EVI was not driven by annual average temperature and annual precipitation. By referencing ecological restoration statistical data and field observations, we showed that ecological restoration programs significantly improved vegetation cover in southern China. Increase in the area of farmland-converted forestlands has reduced soil erosion based upon monitoring sediment yields at hydrologic stations in the Yangtze River. This study displays the spatial patterns of trend in vegetation growth since the beginning of the 21st century in southern China and highlights the important role of ChinaÆs afforestation program. PMID:26115116
Assessing Vegetation Cover Dynamics Induced by Policy-Driven Ecological Restoration and Implication to Soil Erosion in Southern China.
Zhang, Jien; Wang, Tianming; Ge, Jianping
In the aftermath of the severe droughts and floods at the end of the 20th century, the Chinese government launched several ecological restoration projects, including the Natural Forest Protection Program in 1998 and the Grain-for-Green Program in 1999, to promote afforestation and reforestation to reduce surface runoff and consequent soil erosion nationwide. However, it is still unclear how vegetation has changed in southern China since the launch of these programs. In this study, we used the MODIS Enhanced Vegetation Index (EVI) to analyze the vegetation cover dynamics in southern China from 2000 to 2009 and evaluate the resulting effects of controlling soil erosion. Our observations indicate that 5.3% of the study area significantly increased and 0.98% significantly decreased in EVI value (p < 0.05). The spring EVI had largest increase in space. The conversions of croplands on steep slopes to forests resulting from national policies led to significant increases in EVI. The increase in EVI was not driven by annual average temperature and annual precipitation. By referencing ecological restoration statistical data and field observations, we showed that ecological restoration programs significantly improved vegetation cover in southern China. Increase in the area of farmland-converted forestlands has reduced soil erosion based upon monitoring sediment yields at hydrologic stations in the Yangtze River. This study displays the spatial patterns of trend in vegetation growth since the beginning of the 21st century in southern China and highlights the important role of China's afforestation program. PMID:26115116
Ontology-based Intelligent Decision Support Agent for CMMI Project Monitoring and Control
Chang-Shing Lee; Mei-Hui Wang; Jui-Jen Chen; Chin-Yuan Hsu
This paper presents an ontology-based intelligent decision support agent (OIDSA) to apply to project monitoring and control (PMC) of capability maturity model integration (CMMI). The OIDSA is composed of three agents, namely a natural language processing agent, a fuzzy inference agent and a performance decision support agent. All the needed information is stored into an ontology repository, including the CMMI
The Santa Margarita River Arundo donax Control Project: Development of Methods and Plant Community Response1
Dawn M. Lawson; Jesse A. Giessow; Jason H. Giessow
A large-scale effort to control the aggressively invasive exotic species Arundo donax in the Santa Margarita River watershed in California's south coast ecoregion was initiated in 1997. The project was prompted by the need for Marine Corps Base Camp Pendleton to address impacts to habitat for federally-listed endangered species and wetlands regulated by the Army Corps of Engineers. As of
Project EARTH-13-DP1: Understanding biological processes controlling metal isotopes in the oceans
Henderson, Gideon
Project EARTH-13-DP1: Understanding biological processes controlling metal isotopes in the oceans) on different plankton, diatoms, and other biological materials. Techniques using isotopic labelling of metals onto surfaces may also lead to isotopic fractionation, leading to isotopic shifts in the remaining
University of Nevada Las Vegas Arduino Project Report: Fan Speed Control as a Function of Thermistor
Kachroo, Pushkin
University of Nevada Las Vegas Arduino Project Report: Fan Speed Control as a Function, and an arduino board. The arduino board is programmed to read the analog input, the thermistor, and respond by the arduino that will decrease the speed of the fan. Furthermore, if the temperature goes up, the resistance
Testing for supply-limited chemical erosion in field measurements of soil production and chemical depletion
NASA Astrophysics Data System (ADS)
Ferrier, K.; Riebe, C. S.; Hahm, W. J.; Kirchner, J. W.
Quantifying the controls on chemical erosion rates in eroding landscapes is of wide interest because chemical erosion influences nutrient supply, landscape evolution, soil production, and Earth's long-term climate. Several field studies have suggested that chemical erosion rates increase in proportion to the rates that minerals are supplied to the regolith, a condition known as supply-limited chemical erosion. This condition, if broadly applicable, implies strong tectonic control of silicate weathering rates and hence Earth's long-term climate. While it is plausible that chemical erosion rates should scale with supply rates, attempts to test whether chemical erosion rates are in fact supply-limited at any given site are hampered by several difficulties. For instance, the quantities that are most frequently used to test for supply limitation (i.e., rates of chemical erosion and denudation in regolith-based studies, and fluxes of sediment and solutes in river-based studies) are artifactually correlated, which complicates attempts to regress one variable against another. Here we present a statistical method for testing for supply-limited chemical erosion, and we apply this method to a number of published datasets. Our results suggest that many datasets are inadequate for determining whether chemical erosion in regolith is or is not supply-limited, largely because the uncertainties on the regression parameters are large. This in turn suggests that new measurements across a wide range of supply rates are needed to determine the strength of tectonic controls on chemical erosion, and, ultimately, to test hypotheses about feedbacks between surface processes, silicate weathering, and the long-term evolution of Earth's climate.
Auditory cortex controls sound-driven innate defense behaviour through corticofugal projections to inferior colliculus
Xiong, Xiaorui R.; Liang, Feixue; Zingg, Brian; Ji, Xu-ying; Ibrahim, Leena A.; Tao, Huizhong W.; Zhang, Li I.
Defense against environmental threats is essential for animal survival. However, the neural circuits responsible for transforming unconditioned sensory stimuli and generating defensive behaviours remain largely unclear. Here, we show that corticofugal neurons in the auditory cortex (ACx) targeting the inferior colliculus (IC) mediate an innate, sound-induced flight behaviour. Optogenetic activation of these neurons, or their projection terminals in the IC, is sufficient for initiating flight responses, while the inhibition of these projections reduces sound-induced flight responses. Corticocollicular axons monosynaptically innervate neurons in the cortex of the IC (ICx), and optogenetic activation of the projections from the ICx to the dorsal periaqueductal gray is sufficient for provoking flight behaviours. Our results suggest that ACx can both amplify innate acoustic-motor responses and directly drive flight behaviours in the absence of sound input through corticocollicular projections to ICx. Such corticofugal control may be a general feature of innate defense circuits across sensory modalities. PMID:26068082
Scanning-electron-microscope study of normal-impingement erosion of ductile metals
NASA Technical Reports Server (NTRS)
Brainard, W. A.; Salik, J.
Scanning electron microscopy was used to characterize the erosion of annealed copper and aluminum surfaces produced by both single- and multiple-particle impacts. Macroscopic 3.2 mm diameter steel balls and microscopic, brittle erodant particles were projected by a gas gun system so as to impact at normal incidence at speeds up to 140 m/sec. During the impacts by the brittle erodant particles, at lower speeds the erosion behavior was similar to that observed for the larger steel balls. At higher velocities, particle fragmentation and the subsequent cutting by the radial wash of debris created a marked change in the erosion mechanism.
Quantitative Assessment of Agricultural Runoff and Soil Erosion Using Mathematical Modeling
Arhonditsis, George B.
control measures, such as management practices for soil and water conservation and changes in land usesQuantitative Assessment of Agricultural Runoff and Soil Erosion Using Mathematical Modeling non- point source nutrient loading from agricultural watersheds of the Mediterranean region
Southwest Washington Coastal Erosion Study
NSDL National Science Digital Library
The Columbia River is experiencing a far too common problem of disastrous coastal erosion that has been causing grave concern in its community. Because of this, the US Geological Survey Coastal and Marine Geology Program and the Washington Department of Ecology created the Southwest Washington Coastal Erosion Study to predict management scale coastal change, and provide "coastal communities with decision support tools for integrating scientific research with coastal decision making and long-term land use planning efforts." Visitors can discover the study's approach, findings, and participants. The lengthy, informative research link provides information about the study's five key components: coastal change, sediment budget, coastal processes, predictive modeling, and management support. The authors are currently compiling the data collected. Presently, researchers can find data about the beach profiles and the shorelines. The website offers a great, thorough glossary to assist users with unfamiliar terminology. This site is also reviewed in the June 11, 2004 _NSDL Physical Sciences Report_.
BCAUS Project description and consideration of separation of data and control
NASA Technical Reports Server (NTRS)
Bush, Joy L.; Weaver, Steven J.
The commonly stated truths that data may be segregated from program control in generic expert system shells and that such tools support straightforward knowledge representation were examined. The ideal of separation of data from program control in expert systems is difficult to realize for a variety of reasons. One approach to achieving this goal is to integrate hybrid collections of specialized shells and tools instead of producing custom systems built with a single all purpose expert system tool. Aspects of these issues are examined in the context of a specific diagnostic expert system application, the Backup Control Mode Analysis and Utility System (BCAUS), being developed for the Gamma Ray Observatory (GRO) spacecraft. The project and the knowledge gained in working on the project are described.
Ultrasonic cavitation erosion of nodular cast iron with ferrite-pearlite microstructure.
Mitelea, Ion; Bordea?u, Ilare; Pelle, Marius; Cr?ciunescu, Corneliu
The cavitation erosion of ductile cast iron with ferrite-pearlite microstructure was analyzed based on ultrasonic experiments performed according to ASTM G32-2010 and the resistance was compared to the C45 steel with similar hardness. The microstructural observation of the surface for different exposure times to the ultrasonic cavitation reveals the fact that the process initiates at the nodular graphite-ferrite interface and is controlled by micro-galvanic activities and mechanical factors. The cavitation erosion resistance was evaluated based on the evolution of the mean depth erosion and the mean depth erosion rate as a function of the cavitation time. The cavitation erosion rate of the cast iron is up to 1.32 times higher than the one of the C 45 steel with similar hardness. This is explained by the occurrence of stress concentrators due to the expulsion of the graphite from the metallic matrix. PMID:25465881
Cavitation erosion of cobalt based STELLITE alloys, cemented carbides and surface treated low alloy steels
Heathcock, C.J. (Cape Town, Univ., Rondebosch, Republic of South Africa); Ball, A.
Results are given for erosion-resistance tests involving several STELLITE alloys, cemented carbides and surface-treated alloy steels. It is shown that the cobalt-rich, solid-solution phase of the STELLITE alloys is the basis of their erosion resistance, while the erosion of cemented carbides is predominantly controlled by the binder phase. It is also found that nickel-based tungsten carbides are more erosion-resistant than those based on cobalt. It is demonstrated for the case of the low-alloy steels that surface treatment can improve their erosion rates, and that application of a proprietary nitrocarburizing method to the same steels results in a similar performance improvement only after the initial loss of the compound layer.
Effect of endurance training on dental erosion, caries, and saliva.
Frese, C; Frese, F; Kuhlmann, S; Saure, D; Reljic, D; Staehle, H J; Wolff, D
The aim of this investigation was to give insights into the impact of endurance training on oral health, with regard to tooth erosion, caries, and salivary parameters. The study included 35 triathletes and 35 non-exercising controls. The clinical investigation comprised oral examination, assessment of oral status with special regard to caries and erosion, saliva testing during inactivity, and a self-administered questionnaire about eating, drinking, and oral hygiene behavior. In addition, athletes were asked about their training habits and intake of beverages and sports nutrition. For saliva assessment during exercise, a subsample of n?=?15 athletes volunteered in an incremental running field test (IRFT). Athletes showed an increased risk for dental erosion (P?=?0.001). No differences were observed with regard to caries prevalence and salivary parameters measured during inactivity between athletes and controls. Among athletes, a significant correlation was found between caries prevalence and the cumulative weekly training time (r?=?0.347, P?=?0.04). In athletes after IRFT and at maximum workload, saliva flow rates decreased (P?=?0.001 stimulated; P?=?0.01 unstimulated) and saliva pH increased significantly (P?=?0.003). Higher risk for dental erosions, exercise-dependent caries risk, and load-dependent changes in saliva parameters point out the need for risk-adapted preventive dental concepts in the field of sports dentistry. PMID:24917276
Impact of Climate Change on Inland Northwest Soil Erosion Under Various Land Management Practices
NASA Astrophysics Data System (ADS)
Farrell, P.; Abatzoglou, J. T.; Brooks, E. S.
Changes in climate are hypothesized to have a multitude of impacts on the agricultural productivity of the inland Northwest of the United States. Much of the agricultural land in the region is composed of winter wheat and is managed under various tilling practices. Soil erosion under these various tilling practices and climate could be detrimental to the agricultural economy of the region and food security. We explore the susceptibility of the agricultural land of the region to erosion impacts under future climate scenarios using a two-pronged approach using the Water Erosion Prediction Project (WEPP) model. First, we assess the sensitivity of soil erosion to changes in climate variables including precipitation, temperature and precipitation intensity. This sensitivity analysis is done across several geographic regions, different hill slopes, soil types and land management practices. Secondly, we use downscaled climate projections from 20 climate models for the mid-21st century to develop probabilistic estimates of changes in soil erosion across the region. These projected changes are further contextualized using the sensitivity experiments. Finally, we examine whether changes in erosion due to climate change may be partially offset by changes in land management.
Trend analyses of sediment data for the DEC project
Rebich, Richard Allen
Daily stream discharge, suspended-sediment concentration, and suspended-sediment discharge data were collected at eight sites in six watersheds of the Demonstration Erosion Control project in the Yazoo River Basin in north-central Mississippi during the period July 1985 through September 1991. The project is part of an ongoing interagency program of planning, design, construction, monitoring, and evaluation to alleviate flooding, erosion, sedimentation, and water-quality problems for watersheds located in the bluff hills upstream of the Mississippi River alluvial plain. This paper presents preliminary results of trend analyses for stream discharge and sediment data for the eight project sites. More than 550 stream discharge measurements and 20,000 suspended-sediment samples have been collected at the eight sites since 1985.
Resilient Propulsion Control Research for the NASA Integrated Resilient Aircraft Control (IRAC) Project
NASA Technical Reports Server (NTRS)
Guo, Ten-Huei; Litt, Jonathan S.
Gas turbine engines are designed to provide sufficient safety margins to guarantee robust operation with an exceptionally long life. However, engine performance requirements may be drastically altered during abnormal flight conditions or emergency maneuvers. In some situations, the conservative design of the engine control system may not be in the best interest of overall aircraft safety; it may be advantageous to "sacrifice" the engine to "save" the aircraft. Motivated by this opportunity, the NASA Aviation Safety Program is conducting resilient propulsion research aimed at developing adaptive engine control methodologies to operate the engine beyond the normal domain for emergency operations to maximize the possibility of safely landing the damaged aircraft. Previous research studies and field incident reports show that the propulsion system can be an effective tool to help control and eventually land a damaged aircraft. Building upon the flight-proven Propulsion Controlled Aircraft (PCA) experience, this area of research will focus on how engine control systems can improve aircraft safe-landing probabilities under adverse conditions. This paper describes the proposed research topics in Engine System Requirements, Engine Modeling and Simulation, Engine Enhancement Research, Operational Risk Analysis and Modeling, and Integrated Flight and Propulsion Controller Designs that support the overall goal.
Soil erosion estimation based on rainfall disaggregation
NASA Astrophysics Data System (ADS)
Jebari, S.; Berndtsson, R.; Olsson, J.; Bahri, A.
SummarySoil loss estimation remains one of the most difficult research tasks all over the world. Current simulation tools are still not detailed enough to allow for realistic scenarios to handle soil erosion problems. A common problem is the lack of rainfall data at a sufficient level of detail. The present study uses a cascade disaggregation model to generate short time scale rainfall data, needed to calculate the erosivity index in erosion modeling. The model is used to determine the spatial soil loss rate by the Revised Universal Soil Loss Equation and a GIS approach. Comparison between observed and generated data in terms of erosive rainfall characteristics shows that the erosivity factor is over-estimated. This is caused by an over-estimation of short rainfall events. Consequently, different duration limits beyond which erosive events could be considered within the generated series were used to estimate the model performance curve. This provided a suitable duration limit needed to reproduce the observed erosivity. The results showed that generated series only considering rainfall events superior than 90 min are appropriate. This procedure provides a soil loss rate less than 10% under-estimation. Moreover, using Masson, Wischmeier-Smith's and recent erosion limit intervals gave a realistic spatial erosion distribution. The results are promising and can be used to better manage erosion-prone soils.
Observe river erosion creating waterfalls and chasms
NSDL National Science Digital Library
TERC. Center for Earth and Space Science Education
In this resource about river erosion, students are presented with an animation and accompanying text. The resource explains and reveals how, over time, moving water can erode the rock in a river's bed and banks. The opening scenario is that of a small waterfall with a plunge pool at the bottom of the fall. Eventually, the action of the water as it churns gravel and sand about at the foot of the fall causes the plunge pool to grow, the rock above it to collapse, and the waterfall to extend. Movie controls allow students to pause or replay the animation or to step through it one frame at a time. Copyright 2005 Eisenhower National Clearinghouse
Standiford, Richard B.
THE WILDCAT-SAN PABLO CREEK FLOOD CONTROL PROJECT AND ITS IMPLICATIONS FOR THE DESIGN OF ENVIRONMENTALLY SENSITIVE FLOOD MANAGEMENT PLANS1 A. L. Riley 2 1 Presented at the California Riparian Systems type of joint federal and local flood control project on Wildcat and San Pablo Creeks in North Richmond
Project W-211, initial tank retrieval systems, retrieval control system software configuration management plan
This Software Configuration Management Plan (SCMP) provides the instructions for change control of the W-211 Project, Retrieval Control System (RCS) software after initial approval/release but prior to the transfer of custody to the waste tank operations contractor. This plan applies to the W-211 system software developed by the project, consisting of the computer human-machine interface (HMI) and programmable logic controller (PLC) software source and executable code, for production use by the waste tank operations contractor. The plan encompasses that portion of the W-211 RCS software represented on project-specific AUTOCAD drawings that are released as part of the C1 definitive design package (these drawings are identified on the drawing list associated with each C-1 package), and the associated software code. Implementation of the plan is required for formal acceptance testing and production release. The software configuration management plan does not apply to reports and data generated by the software except where specifically identified. Control of information produced by the software once it has been transferred for operation is the responsibility of the receiving organization.
Fate of 90Sr and U(VI) in Dounreay sediments following saline inundation and erosion.
Eagling, Jane; Worsfold, Paul J; Blake, William H; Keith-Roach, Miranda J
There is concern that sea level rise associated with projected climate change will lead to the inundation, flooding and erosion of soils and sediments contaminated with radionuclides at coastal nuclear sites, such as Dounreay (UK), with seawater. Here batch and column experiments were designed to simulate these scenarios and sequential extractions were used to identify the key radionuclide solid phase associations. Strontium was exchangeable and was mobilised rapidly by ion exchange with seawater Mg(2+) in both batch and column experiments. In contrast, U was more strongly bound to the sediments and mobilisation was initially limited by the influence of the sediment on the pH of the water. Release was only observed when the pH increased above 6.9, suggesting that the formation of soluble U(VI)-carbonate species was important. Under dynamic flow conditions, long term release was significant (47%), but controlled by slow desorption kinetics from a range of binding sites. PMID:23541149
Sandstorms and eolian erosion on Mars.
NASA Technical Reports Server (NTRS)
Sagan, C.
Erosion rates are calculated for Mars from first principles and calibrated from wind tunnel experiments. The deduced abrasion rates are higher than eolian erosion rates on the earth because of the higher threshold velocities on Mars but lower than the total erosion rates on the earth because of the absence of aqueous erosion processes on contemporary Mars. The high erosion rates imply that, for scale lengths of less than a few hundred kilometers, Mars may be viewed only part way back to its ancient history. Because the meteorology of Mars is position-dependent, erosion rates may vary greatly from place to place. Martian sandstorms may be characterized by frequent grain-grain collisions, and the grain velocities and cloud height may approach values implied by the Maxwell-Boltzmann velocity distribution.
Connecting Surface Planting with Subsurface Erosion Due to Groundwater Flow
NASA Astrophysics Data System (ADS)
Reardon, M.; Curran, J. C.
Bank erosion and failure is a major contributor of fine sediment to streams and rivers, and can be driven by subsurface flow. In restoration projects, vegetation is often planted on banks to reduce erosion and stabilize the banks. However, the relationship between subsurface flow, erosion and vegetation remains somewhat speculative. A comparative study quantified the effect of surface planting on subsurface erosion and soil strength. Six 32-gallon containers were layered with a sandy loam overlying a highly conductive sand layer and a confining clay. Three treatments were applied in pairs: switchgrass (Panicum virgatum L.), sod (turf-type tall fescue and Kentucky bluegrass mix), and no vegetation. After a vegetation establishment period, the 2, 10, and 100 year rainfalls were simulated. Samples collected from ports in the containers were analyzed for subsurface drainage volume and suspended sediment concentration. After all rainfall simulations, a sediment core was taken from each container to measure shear strength and root density. Results indicate the relative benefits of vegetative planting to reduce subsurface erosion during storms and enhance soil strength. Switchgrass reduced the total amount of sediment removed from containers during all three storms when compared to the sod and during the 10 and 100 year storms when compared to the bare ground. Results from the volume analysis were more variable. Switchgrass retained the greatest volume of water from the 100 year storm event, but also released the largest fraction of water in the 2 and 10 year storms. Both sod and switchgrass planting considerably increased the time required for the soil samples to fail despite reducing the shear stress at failure. Where switchgrass grew long, woody roots, the sod developed a dense mat of interconnected thin roots. We suspect the different root patterns between sod and switchgrass to be a dominant factor in the response of the different containers.
The objective of this study was to demonstrate the effectiveness of surface mined land reclamation measures in establishing surface water infiltratin control to prevent or reduce pollution from acid mine drainage. The Dents Run watershed, located in Monongalia County, West Virgin...
Philip Morris's Project Sunrise: weakening tobacco control by working with it
McDaniel, P A; Smith, E A; Malone, R E
Objective To analyse the implications of Philip Morris USA's (PM's) overtures toward tobacco control and other public health organisations, 1995¢2006. Data sources Internal PM documents made available through multi?state US attorneys general lawsuits and other cases, and newspaper sources. Methods Documents were retrieved from several industry documents websites and analysed using a case study approach. Results PM's Project Sunrise, initiated in 1995 and proposed to continue through 2006, was a long?term plan to address tobacco industry delegitimisation and ensure the social acceptability of smoking and of the company itself. Project Sunrise laid out an explicit divide?and?conquer strategy against the tobacco control movement, proposing the establishment of relationships with PM?identified ōmoderateö tobacco control individuals and organisations and the marginalisation of others. PM planned to use ōcarefully orchestrated effortsö to exploit existing differences of opinion within tobacco control, weakening its opponents by working with them. PM also planned to thwart tobacco industry delegitimisation by repositioning itself as ōresponsibleö. We present evidence that these plans were implemented. Conclusion Sunrise exposes differences within the tobacco control movement that should be further discussed. The goal should not be consensus, but a better understanding of tensions within the movement. As the successes of the last 25 years embolden advocates to think beyond passage of the next clean indoor air policy or funding of the next cessation programme, movement philosophical differences may become more important. If tobacco control advocates are not ready to address them, Project Sunrise suggests that Philip Morris is ready to exploit them. PMID:16728753
Aeolian Induced Erosion and Particle Entrainment
NASA Technical Reports Server (NTRS)
Saint, Brandon
The Granular Physics Department at The Kennedy Space Center is addressing the problem of erosion on the lunar surface. The early stages of research required an instrument that would produce erosion at a specific rate with a specific sample variation. This paper focuses on the development and experimental procedures to measure and record erosion rates. This was done with the construction of an open air wind tunnel, and examining the relationship between airflow and particle motion.
Erosion processes in granular flows: insights from laboratory experiments
NASA Astrophysics Data System (ADS)
Farin, Maxime; Mangeney, Anne; Roche, Olivier
Experimental granular column collapse were conducted over an inclined channel covered by an erodible bed of granular material in order to reproduce at laboratory scale erosion processes of natural flows propagating over deposits formed by earlier events. The studied control parameters were the slope angle, the aspect ratio (i.e. height over length), the volume and the shape of the granular column released, and the thickness and compaction of the erodible bed. The results show that erosion processes affect the flow runout distance over a critical slope angle ?c that depends on the column volume, aspect ratio, and shape. For slope higher than ?c, the granular avalanche excavates the erodible layer immediately at the flow front, behind which waves traveling downstream are observed and help entraining grains from the erodible bed. Erosion efficiency (i.e. maximal depth and duration of excavation, waves dimensions) is shown to increase as the slope angle and the column's volume increase. It is also dependent on the aspect ratio and on the nature of the erodible bed: the maximal excavation depth and the duration of the excavation decrease as the degree of compaction of the erodible granular bed increases. Erosion processes notably increase granular flows runout distance at inclinations close to the repose angle of the grains, in particular for columns of small aspect ratio. We demonstrate, however, that the flow runout distance observed on an erodible bed cannot be reproduced on a rough bed by simply adding the entrained volume of erodible bed to the initial column volume.
Wasbash River Coal Gasification Repowering Project simulator control logic, design and check-out
Schafer, M.; Broeker, L. [PSI Energy, Plainfield, IN (United States); Craddock, D. [DMCI, Charlottesville, VA (United States); Salm, R. [Power Safety International, Lynchburg, VA (United States)
PSI Energy is using real-time, dynamic simulation of the Wabash River Coal Gasification Repowering Project (WRCGRP). The simulator, which was configured by Power Safety International, DMCI and Trax, uses modular modeling based process models to stimulate ICDAS hardware. The authors are using the simulator to concentrate on many critical areas including: control philosophy verification, plant design, operating procedures, operator training and controls checkout. The simulator is saving costs and time. This paper will discuss the simulator and the benefits the authors are realizing from it.
Sorbent injection into a slipstream baghouse for mercury control: Project summary
Jeffrey S. Thompson; John H. Pavlish; Lucinda L. Hamre; Melanie D. Jensen; David Smith; Steve Podwin; Lynn A. Brickett
A project led by the Energy and Environmental Research Center to test and demonstrate sorbent injection as a cost-effective mercury control technology for utilities burning lignites has shown effective mercury capture under a range of operating conditions. Screening, parametric, and long-term tests were carried out at a slipstream facility representing an electrostatic precipitator¢activated carbon injection¢fabric filter configuration (called a TOXECONÖ
The Design of an Object-Oriented, Distributable Camera Control System for the Ultracam Project
Chris Tierney; Steven Beard
Recent experience of camera systems, at the UKATC and elsewhere, has centred around a familiar vxWorks\\/VME-based architecture utilizing SDSU camera control hardware. In these systems, tight coupling between the host vxWorks software and low-level DSP code has greatly increased the software effort required to maintain and upgrade such systems. The Ultracam project will use updated hardware and a software design
Implementing the theories: A fully integrated project control system that`s implemented and works
Using the theories presented in DOE Orders 4700.1, 1332.1A, and Notice 4700.5 as the basis for system design, the Fernald Environmental Restoration Management Corporation (FERMCO) has developed and implemented a Project Control System (PCS) that complies with requirements and provides DOE and FERMCO management with timely performance measurement information. To this extent, the FERMCO PCS probably is similar to the
Autocyclic erosion in tidal marshes
NASA Astrophysics Data System (ADS)
Singh Chauhan, Poornendu P.
A common mode whereby destruction of coastal lowlands occurs is frontal erosion. The edge cliffing, nonetheless, is also an inherent aspect of salt marsh development in many northwest European tidal marshes. Quite a few geomorphologists in the earlier half of the past century recognized such edge erosion as a definite repetitive stage within an autocyclic mode of marsh growth. A shift in research priorities during the past decades (primarily because of coastal management concerns, however) has resulted in an enhanced focus on sediment-flux measurement campaigns on salt marshes. This, somewhat "object-oriented" strategy hindered any further development of the once-established autocyclic growth concept, which virtually has gone into oblivion in recent times. This work makes an attempt to resurrect the notion of autocyclicity by employing its premises to address edge erosion in tidal marshes. Through a review of intertidal morphosedimentology the underlying framework for autocyclicity is envisaged. The phenomenon is demonstrated in the Holocene salt marsh plain of Moricambe basin in NW England that displays several distinct phases of marsh retreat in the form of abandoned clifflets. The suite of abandoned shorelines and terraces has been identified in detailed field mapping that followed analysis of topographic maps and aerial photographs. Vertical trends in marsh plain sediments are recorded in trenches for signs of past marsh front movements. The characteristic sea level history of the area offers an opportunity to differentiate the morphodynamic variability induced in the autocyclic growth of the marsh plain in scenarios of rising and falling sea level and the accompanied change in sediment budget. The ideas gathered are incorporated to construct a conceptual model that links temporal extent of marsh erosion to inner tidal flat sediment budget and sea level tendency. The review leads to recognition of the necessity of adopting an holistic approach in the morphodynamic investigations where marshes should be treated as a component within the "marsh-mudflat system" as each element apparently modulates evolution of the other, with an eventual linkage to subtidal channels.
Erosive arthritis in relapsing polychondritis.
Jawad, A. S.; Burrel, M.; Lim, K. L.; Scott, D. G.
We report the case history of a 57 year old man who has suffered from typical deforming, relapsing polychondritis for 13 years. He has also developed erosive destructive seronegative polyarthritis involving some of his distal interphalangeal, proximal interphalangeal, metacarpophalangeal, intercarpal, wrist, intertarsal and metatarsophalangeal joints. The distribution of joint involvement in the small joints of the hands and feet is asymmetrical. Both hips and knee joints have also been involved necessitating bilateral total hip and right total knee replacement. The articular associations with relapsing polychondritis are discussed. Images Figure 1 Figure 2 Figure 3 PMID:2235813
Coastal Erosion: Where's the Beach?
NSDL National Science Digital Library
This data tip from Bridge, the Ocean Sciences Education Teacher Resource Center archive, explores erosion and accretion of coastal sediments, the two processes that keep our beaches in a constant state of change. Both natural and not-so-natural factors influencing these processes are discussed. Learners can view a variety of weblinks on the topic and conduct their own beach profile investigation, or access profile data from a 1999 Ocean City, Maryland beach and plot the changes over time for a graphic illustration of these processes.
Erosion Modeling Analysis for SME Tank Cavity
Previous computational work to evaluate erosion in the DWPF Slurry Mix Evaporator vessel has been extended to address the potential for the erosion to accelerate because of changes to the tank bottom profile. The same erosion mechanism identified in the previous work, abrasive erosion driven by high wall shear stress, was applied to the current evaluation. The current work extends the previous analysis by incorporating the observed changes to the tank bottom and coil support structure in the vicinity of the coil guides. The results show that wall shear on the tank bottom is about the same magnitude as found in previous results. Shear stresses in the eroded cavities are reduced compared to those that caused the initial erosion to the extent that anticipated continued erosion of those locations is minimal. If SR operations were continued at an agitator speed of 130 rpm, the edge of the existing eroded cavities would probably smooth out, while the rate of erosion at the bottom of the cavity would decrease significantly with time. Further, reducing the agitator speed to 103 rpm will reduce shear stresses throughout the bottom region of the tank enough to essentially preclude any significant continued erosion. Because this report is an extension to previously documented work, most background information has been omitted. A complete discussion of the motivation for both the analysis and the modeling is provided in Lee et al., ''Erosion Modeling Analysis for Modified DWPF SR Tank''.
Comparison of erosion and channel characteristics
Parker, Gene W.
Erosion was observed at 33 percent of 22,495 bridge sites in nine States. Among sites with erosion, 56 percent were associated with skewed flows, curved channels, or a combination of these two conditions, and at 18 percent of the sites, channels were straight with steep bank angles. The remaining 26 percent are sites with observable erosion at piers or abutments on straight channels. Comparison of the sites with erosion to channel bed-material indicate that 44 percent of the single-span sites had gravel-size or smaller bed material and 70 percent of the multiple-span sites had gravel-size or smaller bed material.
High temperature erosion of nickel alloys
Zhou, J. [Prairie View A and M Univ., Prairie View, TX (United States). Dept. of Mechanical Engineering
High temperature erosion behavior was studied on three commercial nickel alloys, Inconel 718, Inconel 601 and Inconel X-750, using a vertical sand-blast type of erosion test rig. Effect of temperature on erosion was investigated by varying test temperature in six steps from ambient up to 800 C. Other erosion variables investigated included impingement angle, changed from 10{degree} to 90{degree}, and impingement velocity, covered a range of 40 to 90 m/s. Extensive studies on erosion surface morphological features were done on eroded or eroded-corroded specimen surfaces using scanning electron microscopy. Thermogravimetric analysis and scratch test revealed corrosion rate, characteristics of oxide scale formed at high temperature, and some effects of corrosion on erosion. It was found that variation of erosion rate with temperature was directly related to temperature-dependent mechanical property changes of the materials. The mechanisms of the high-temperature erosion were analyzed based on test results. It was observed that erosion was dominant in temperature range up to 800 C, while corrosion played increased roles in upper portion of the temperature range tested.
Modeling aeolian erosion in presence of vegetation
NASA Astrophysics Data System (ADS)
Dupont, S.; Bergametti, G.; Simoļns, S.
Semiarid landscapes are characterized by vegetated surfaces. Understanding the impact of vegetation on aeolian soil erosion is important for reducing soil erosion or limiting crop damage through abrasion or burial. In the present study, a saltation model fully coupled with a large-eddy simulation airflow model is extended to vegetated landscapes. From this model, the sensitivity of sand erosion to different arrangements and type of plants (shrub versus tree) representative of semiarid landscapes is investigated and the wind erosion reduction induced by plants is quantified. We show that saltation processes over vegetated surfaces have a limited impact on the mean wind statistics, the momentum extracted from the flow by saltating particles being negligible compared to that extracted by plants. Simulated sand erosion patterns resulting from plant distribution, i.e., accumulation and erosion areas, appear qualitatively consistent with previous observations. It is shown that sand erosion reduction depends not only on vegetation cover but also on plant morphology and plant distribution relative to the mean wind direction. A simple shear stress partitioning approach applied in shrub cases gives similar trends of sand erosion reduction as the present model following wind direction and vegetation cover. However, the magnitude of the reduction appears significantly different from one approach to another. Although shrubs trap saltating particles, trees appear more efficient than shrubs to reduce sand erosion. This is explained by the large-scale sheltering effect of trees compared to the local shrub one.
Soil erosion-vegetation interactions in Mediterranean-dry reclaimed mining slopes
NASA Astrophysics Data System (ADS)
Moreno de las Heras, Mariano; Merino-MartĒn, Luis; Espigares, TĒscar; Nicolau, Josķ M.
Mining reclamation in Mediterranean-dry environments represents a complex task. Reclaimed mining slopes are particularly vulnerable to the effects of accelerated soil erosion processes, especially when these processes lead to the formation of rill networks. On the other hand, encouraging early vegetation establishment is perceived as indispensable to reduce the risk of degradation in these man-made ecosystems. This study shows a synthesis of soil erosion-vegetation research conducted in reclaimed mining slopes at El Moral field site (Teruel coalfield, central-east Spain). Our results highlight the role of rill erosion processes in the development of reclaimed ecosystems. Runoff routing is conditioned by the development of rill networks, maximizing the loss of water resources at the slope scale by surface runoff and altering the spatial distribution of soil moisture. As a result, the availability of water resources for plant growth is drastically reduced, affecting vegetation development. Conversely, vegetation exerts a strong effect on soil erosion: erosion rates rapidly decrease with vegetation cover and no significant rill erosion is usually observed after a particular cover threshold is reached. These interactive two-way vegetation-soil erosion relationships are further studied using a novel modeling approach that focuses on stability analysis of water-limited reclaimed slopes. Our framework reproduces two main groups of trends along the temporal evolution of reclaimed slopes: successful trends, characterized by widespread vegetation development and the effective control of rill erosion processes; and gullying trends, characterized by the progressive loss of vegetation and a sharp logistic increase in erosion rates. This stability-analysis also facilitates the determination of threshold values for both vegetation cover and rill erosion that drive the long-term reclamation results, assisting the identification of critical situations that require specific human interventions to ensure the long-term sustainability of the restored ecosystems.
Controlled Hydrogen Fleet and Infrastructure Demonstration and Validation Project: Fall 2006 Progress Update
Wipke, K.; Welch, C.; Thomas, H.; Sprik, S.; Gronich, S.; Garbak, J.
The U.S. Department of Energy (DOE) initiated the Controlled Hydrogen Fleet and Infrastructure Demonstration and Validation Project through a competitive solicitation process in 2003. The purpose of this project is to conduct an integrated field validation that simultaneously examines the performance of fuel cell vehicles and the supporting hydrogen infrastructure. Four industry teams have signed cooperative agreements with DOE and are supporting plans for more than 130 fuel cell vehicles and 20 hydrogen refueling stations over the 5-year project duration. This paper provides a status update covering the progress accomplished by the demonstration and validation project over the last six months; the first composite data products from the project were published in March 2006. The composite data products aggregate individual performance into a range that protects the intellectual property of the companies involved, while publicizing the progress the hydrogen and fuel cell industry is making as a whole relative to the program objectives and timeline. Updates to previously published composite data products, such as on-road fuel economy and vehicle/infrastructure safety, will be presented along with new composite data products, such as fuel cell stack efficiency and refueling behavior.
Some practical examples of cavitation erosion and their prevention
NASA Technical Reports Server (NTRS)
Conn, A. F.
The problem of failures caused by cavitation erosion are discussed. The concepts of intensity of erosion, erosion strength, and the time dependence of erosion rate are analyzed. The relation of these parameters to system variables such as pressure and velocity, and to the properties of materials are investigated. Using several examples of actual cavitation erosion, methods of prevention and their limitations are examined.
Prediction of erosiveness and rate of development of new erosions in early rheumatoid arthritis
T T M÷tt÷nen
Fifty eight patients suffering from a recent onset of rheumatoid arthritis (RA) were studied. Fifty six patients were followed up for 24 months and two for 18 months. Erosions were detected in 17 patients at the onset and at the end of the follow up period the number of patients with erosions was 44. The erosiveness in the joint groups
A seepage erosion sediment transport function and geometric headcut relationships for predicting seepage erosion undercutting
Technology Transfer Automated Retrieval System (TEKTRAN)
Seepage erosion is an important factor in hillslope instability and failure. However, predicting erosion by subsurface flow or seepage and incorporating its effects into stability models remain a challenge. Limitations exist with all existing seepage erosion sediment transport functions, including n...
Quantifying accelerated soil erosion through ecological site-based assessments of wind and water erosion
Technology Transfer Automated Retrieval System (TEKTRAN)
This work explores how organising soil erosion assessments using established groupings of similar soils (ecological sites) can inform systems for managing accelerated soil erosion. We evaluated aeolian sediment transport and fluvial erosion rates for five ecological sites in southern New Mexico, USA...
QUANTIFYING ACCELERATED SOIL EROSION THROUGH ECOLOGICAL SITE- BASED ASSESSMENTS OF WIND AND WATER EROSION contact: Nicholas Webb phone: 575-646-3584 email: email@example.com web: http change and intensification have resulted in accelerated rates of soil erosion in many areas of the world
Soil water erosion on Mediterranean vineyards. A review based on published data
NASA Astrophysics Data System (ADS)
Prosdocimi, Massimo; CerdÓ, Artemi; Tarolli, Paolo
Soil water erosion on cultivated lands is a severe threat to soil resources in the world (Leh et al., 2013; Zhao et al., 2013). In particular, Mediterranean areas deserve a particular attention because of their edaphic, topographic and climatic conditions. Among the cultivated lands, concerns have arisen about vineyards because, aside representing one of the most important crop in terms of income and employment, they also have proven to be the form of agricultural land that causes one of the highest soil losses (Tropeano et al., 1984; Leonard and Andrieux, 1998; Ferrero et al., 2005; CerdÓ et al., 2007; Blavet et al., 2009; CasalĒ et al., 2009; Novara et al., 2011; MartĒnez Casasnovas et al., 2013; Ruiz Colmenero et al., 2013; Tarolli et al., 2014). Although the topic of soil water erosion on vineyards has been studied, it still raises uncertainties. These are due to the i) high complexity of processes involved, ii) different methodologies used to analyze them and iii) analyses carried out at different spatial and temporal scales. At this regard, this work aims to evaluate the impact of factors controlling erosion such as rainfall characteristics, topography, soil properties and soil and water conservation techniques. Data derived from experimental plots have been reviewed. At first, what emerges is the difficulty of comparing erosion rates obtained with different methodologies and at different spatial scales. Secondly, all the factors demonstrate to have a strong impact on soil erosion but a 'general rule' upon which to consider one factor always predominant over the others does not come out. Therefore, this work supports the importance of monitoring soil water erosion by field measurements to better understand the relationship between the factors. Variables like rainfall characteristics, topography and soil properties are much more difficult to modify than the soil and water management techniques. Hence, future researches are needed to both recommend the best soil and water management techniques to the farmers and implement soil erosion mitigation policies at appropriate spatial scales. Acknowledgements The RECARE project is funded by the European Commission FP7 program, ENV.2013.6.2-4 "Sustainable land care in Europe". References Blavet, D., De Noni, G., Le Bissonnais, Y., Leonard, M., Maillo, L., Laurent, J.Y., Asseline, J., Leprun, J. C., Arshad, M. A., Roose, E.: Effect of land use and management on the early stages of soil water erosion in French Mediterranean vineyards, Soil & Tillage Research, 106, 124-136, 2009. Brenot, J., Quiquerez, A., Petit, C., Garcia, J.-P., Davy, P.: Soil erosion rates in Burgundian vineyards, Bolletino della SocietÓ Geologica Italiana, Volume Speciale 6, 169-174, 2006. CasalĒ, J., Gimķnez, R., De Santisteban, L., Alvarez-Mozos, J., Mena, J., Del Valle de Lersundi, J.: Determination of long-term erosion rates in vineyards of Navarre (Spain) using botanical benchmarks, Catena, 78, 12-19, doi:10.1016/ j.catena.2009.02.015, 2009. CerdÓ, A., Doerr, S. H.: Soil wettability, runoff and erodibility of major dry-Mediterranean land use types on calcareous soils, Hydrological Processes, 21, 2325-2336, doi: 10.1016/j.catena.2008.03.010, 2007. Ferrero, A., Usowicz, B., Lipiec, J.: Effects of tractor traffic on spatial variability of soil strength and water content in grass covered and cultivated sloping vineyard, Soil & Tillage Research, 84, 127-138, 2005. Leh, M., Bajwa, S., Chaubey, I.: Impact of land use change on erosion risk: and integrated remote sensing geographic information system and modeling methodology, Land Degradation & Development, 24, 409- 421, doi 10.1002/ldr.1137, 2013. Leonard, J., Andrieux, P.: Infiltration characteristics of soils in Mediterranean vineyards in southern France, Catena, 32, 209-223, 1998. Martinez-Casasnovas, J. A., Ramos, M. C., Benites, G.: Soil and water assessment tool soil loss simulation at the sub-basin scale in the Alt PenedĶs-Anoia vineyard region (NE Spain) in the 2000s, Land Degradation & Development, doi: 10.1002/ldr.2
Impact erosion of planetary atmospheres
NASA Astrophysics Data System (ADS)
Shuvalov, Valery
The problem of planetary atmospheres evolution due to impacts of large cosmic bodies was investigated by Ahrens, O'Keefe, Cameron, Hunten and others. These studies were focused mainly on the atmosphere growth under impact devolatilization and atmosphere losses due to escape of high velocity ejecta. Most of the results concerning atmosphere erosion were based on assumption that atmosphere itself does not influence significantly on the ejecta evolution. However more detailed investigations show that atmospheric drag is important at least for 1-10km impactors. From the other hand the theory of large explosions in an exponential atmosphere is not applicable in the case under consideration because of the influence of a trail created during the body flight through the atmosphere. In the present study the problem of 1-10km asteroid impacts against the Earth is investigated with the use of multi-material hydrocode SOVA. This code is similar to the widely used CTH system and allows to model all stages of the impact (penetration into the atmosphere, collision with the ground surface covered by water basin, ejecta evolution). The air mass ejected from each altitude depending on impactor size and velocity is determined. Apart from the impacts into the present-day atmosphere, the erosion of the dense Proto-Atmosphere is also considered.
An estimation method of the direct benefit of a waterlogging control project applicable to the changing environment
NASA Astrophysics Data System (ADS)
Zengmei, L.; Guanghua, Q.; Zishen, C.
The direct benefit of a waterlogging control project is reflected by the reduction or avoidance of waterlogging loss. Before and after the construction of a waterlogging control project, the disaster-inducing environment in the waterlogging-prone zone is generally different. In addition, the category, quantity and spatial distribution of the disaster-bearing bodies are also changed more or less. Therefore, under the changing environment, the direct benefit of a waterlogging control project should be the reduction of waterlogging losses compared to conditions with no control project. Moreover, the waterlogging losses with or without the project should be the mathematical expectations of the waterlogging losses when rainstorms of all frequencies meet various water levels in the drainage-accepting zone. So an estimation model of the direct benefit of waterlogging control is proposed. Firstly, on the basis of a Copula function, the joint distribution of the rainstorms and the water levels are established, so as to obtain their joint probability density function. Secondly, according to the two-dimensional joint probability density distribution, the dimensional domain of integration is determined, which is then divided into small domains so as to calculate the probability for each of the small domains and the difference between the average waterlogging loss with and without a waterlogging control project, called the regional benefit of waterlogging control project, under the condition that rainstorms in the waterlogging-prone zone meet the water level in the drainage-accepting zone. Finally, it calculates the weighted mean of the project benefit of all small domains, with probability as the weight, and gets the benefit of the waterlogging control project. Taking the estimation of benefit of a waterlogging control project in Yangshan County, Guangdong Province, as an example, the paper briefly explains the procedures in waterlogging control project benefit estimation. The results show that the waterlogging control benefit estimation model constructed is applicable to the changing conditions that occur in both the disaster-inducing environment of the waterlogging-prone zone and disaster-bearing bodies, considering all conditions when rainstorms of all frequencies meet different water levels in the drainage-accepting zone. Thus, the estimation method of waterlogging control benefit can reflect the actual situation more objectively, and offer a scientific basis for rational decision-making for waterlogging control projects.
E. Petersen; J. Ali-Adeeb; T. Cerling; M. Chan; D. Chapman; L. Cohen; M. Davis; D. Chapmandearing; S. Hill; S. Hynek; L. Millward; S. O'Grady; L. Richards; K. Solomon; S. Sampson; J. Schafer; L. Zanno; E. Zipser
Project WEST (Water, the Environment, Science, and Teaching) is a graduate student fellowship program funded by a GK-12 grant from the National Science Foundation. WEST links the University of Utah, the Utah Museum of Natural History, and the Salt Lake City school district in enhancing inquiry based science teaching in grades 4, 8, and 9 and the interdisciplinary training of
Storm water control plan for the Lower East Fork Poplar Creek Operable Unit, Oak Ridge, Tennessee
This document provides the Environmental Restoration Program with information about the erosion and sediment control, storm water management, maintenance, and reporting and record keeping practices to be employed during Phase II of the remediation project for the Lower East Fork Poplar Creek (LEFPC) Operable Unit.
Advanced emissions control development project. Final report, November 1, 1993--February 29, 1996. Phase I
Farthing, G.A.
The primary objective of the Advanced Emissions Control Development Program (AECDP) is to develop practical, cost-effective strategies for reducing the emissions of air toxics from coal-fired boilers. Ideally, the project aim is to effectively control air toxic emissions through the use of conventional flue gas cleanup equipment such as electrostatic precipitators (ESPs), fabric filters (baghouses), and wet flue gas desulfurization. B&W`s Clean Environment Development Facility (CEDF) and the AECDP equipment combined to form a state-of-the-art facility for integrated evaluation of combustion and post-combustion emissions control options. Phase I activities were primarily directed at providing a reliable, representative test facility for conducting air toxic emission control development work later in the project. This report summarizes the AECDP Phase I activities which consisted of the design, installation, shakedown, verification, and air toxics benchmarking of the AECDP facility. The AECDP facility consists of an ESP, pulse-jet baghouse, and wet scrubber. All verification and air toxic tests were conducted with a high sulfur, bituminous Ohio coal. In order to successfully apply the results of the program to utility systems, the relationship between the performance of the CEDF/AECDP test equipment and commercial units had to be established. The first step in the verification process was to validate that the flue gas treatment devices - boiler/convection pass simulator, ESP, baghouse, and wet SO{sub 2} scrubber - operate in a manner representative of commercial units.
Predicting coastal cliff erosion using a Bayesian probabilistic model
Hapke, C.; Plant, N.
Regional coastal cliff retreat is difficult to model due to the episodic nature of failures and the along-shore variability of retreat events. There is a growing demand, however, for predictive models that can be used to forecast areas vulnerable to coastal erosion hazards. Increasingly, probabilistic models are being employed that require data sets of high temporal density to define the joint probability density function that relates forcing variables (e.g. wave conditions) and initial conditions (e.g. cliff geometry) to erosion events. In this study we use a multi-parameter Bayesian network to investigate correlations between key variables that control and influence variations in cliff retreat processes. The network uses Bayesian statistical methods to estimate event probabilities using existing observations. Within this framework, we forecast the spatial distribution of cliff retreat along two stretches of cliffed coast in Southern California. The input parameters are the height and slope of the cliff, a descriptor of material strength based on the dominant cliff-forming lithology, and the long-term cliff erosion rate that represents prior behavior. The model is forced using predicted wave impact hours. Results demonstrate that the Bayesian approach is well-suited to the forward modeling of coastal cliff retreat, with the correct outcomes forecast in 70-90% of the modeled transects. The model also performs well in identifying specific locations of high cliff erosion, thus providing a foundation for hazard mapping. This approach can be employed to predict cliff erosion at time-scales ranging from storm events to the impacts of sea-level rise at the century-scale. ?? 2010.
Determination of critical soil water content and matric potential for wind erosion
Kristine Bolte; Peter Hartmann; Heiner Fleige; Rainer Horn
PurposeĀĀSoil strength and thus stability concerning wind erosion are controlled by the soil water content. The concept of soil critical\\u000a water content (?crit.) for deflation was extended to include matric potential (?crit.) as well. The focus of this paper is to quantify the ?crit. and ?crit. as the upper boundary for wind erosion or as the lower boundary for soil
Sensitivity Analysis of a process based erosion model using FAST
NASA Astrophysics Data System (ADS)
Gabelmann, Petra; Wienh÷fer, Jan; Zehe, Erwin
Erosion, sediment redistribution and related particulate transport are severe problems in agro-ecosystems with highly erodible loess soils. They are controlled by various factors, for example rainfall intensity, topography, initial wetness conditions, spatial patterns of soil hydraulic parameters, land use and tillage practice. The interplay between those factors is not well understood. A number of models were developed to indicate those complex interactions and to estimate the amount of sediment which will be removed, transported and accumulated. In order to make use of physical-based models to provide insight on the physical system under study it is necessary to understand the interactions of parameters and processes in the model domain. Sensitivity analyses give insight in the relative importance of model parameters, which in addition is useful for judging where the greatest efforts have to be spent in acquiring or calibrating input parameters. The objective of this study was to determine the sensitivity of the erosion-related parameters in the CATFLOW model. We analysed simulations from the Weiherbach catchment, where good matches of observed hydrological response and erosion dynamics had been obtained in earlier studies. The Weiherbach catchment is located in an intensively cultivated loess region in southwest Germany and due to the hilly landscape and the highly erodible loess soils, erosion is a severe environmental problem. CATFLOW is a process-based hydrology and erosion model that can operate on catchment and hillslope scales. Soil water dynamics are described by the Richards equation including effective approaches for preferential flow. Evapotranspiration is simulated using an approach based on the Penman-Monteith equation. The model simulates overland flow using the diffusion wave equation. Soil detachment is related to the attacking forces of rainfall and overland flow, and the erosion resistance of the soil. Sediment transport capacity and sediment deposition are related to overland flow velocity using the equation of Engelund and Hansen and the sinking velocity of grain sizes, respectively. The sensitivity analysis was performed based on virtual hillslopes similar to those in the Weiherbach catchment. We applied the FAST-method (Fourier Amplitude Sensitivity Test), which provides a global sensitivity analysis with comparably few model runs. We varied model parameters in predefined and, for the Weiherbach catchment, physically meaningful parameter ranges. Those parameters included rainfall intensity, surface roughness, hillslope geometry, land use, erosion resistance, and soil hydraulic parameters. The results of this study allow guiding further modelling efforts in the Weiherbach catchment with respect to data collection and model modification.
Generalized projective synchronization of the fractional-order chaotic system using adaptive fuzzy sliding mode control
NASA Astrophysics Data System (ADS)
Wang, Li-Ming; Tang, Yong-Guang; Chai, Yong-Quan; Wu, Feng
An adaptive fuzzy sliding mode strategy is developed for the generalized projective synchronization of a fractional-order chaotic system, where the slave system is not necessarily known in advance. Based on the designed adaptive update laws and the linear feedback method, the adaptive fuzzy sliding controllers are proposed via the fuzzy design, and the strength of the designed controllers can be adaptively adjusted according to the external disturbances. Based on the Lyapunov stability theorem, the stability and the robustness of the controlled system are proved theoretically. Numerical simulations further support the theoretical results of the paper and demonstrate the efficiency of the proposed method. Moreover, it is revealed that the proposed method allows us to manipulate arbitrarily the response dynamics of the slave system by adjusting the desired scaling factor ?i and the desired translating factor ?i, which may be used in a channel-independent chaotic secure communication.
Application of ERTS-1 imagery to detecting and mapping modern erosion features, and to monitoring erosional changes, in southern Arizona
NASA Technical Reports Server (NTRS)
Morrison, R. B. (principal investigator); Cooley, M. E.
The author has identified the following significant results. ERTS-1 multispectral images have been used, without additional data, to prepare three maps at 1:1 million scale of the 18,000 sq. mi. project area: (1) modern (post-1890 A. D.) arroyos and channels; (2) types of stream channels; and (3) potential erodibility of soils; surficial deposits, and bedrock. Also completed was the collection and compilation of ground truth geologic, soil, and hydrologic data. Field studies to obtain ground control for the photointerpretive mapping include: (1) measurements, at many sites, of the depth, width, and channel characteristics of arroyos and gullies, and cross profiles of stream channels, flood plains, and Holocene terraces; and (2) stratigraphic measurements of the Holocene alluvial deposits. Significant conclusions from these extensive stratigraphic studies are: Slow deposition of sediment was the dominant process on stream lowlands throughout the project area for at least 2000 years prior to 1890 A.D. The deposition was broken by only two relatively brief and minor erosional episodes of regional importance, when channels no more than a third of the depth of modern channels were cut. The modern erosion has produced within about 80 years substantially more and larger arroyos than any erosion episode during the last 2000 years, and the end is not in sight.
Distribution automation and control support; Analysis and interpretation of DAC working group results for use in project planning
NASA Technical Reports Server (NTRS)
Klock, P.; Evans, D.
The Executive Summary and Proceedings of the Working Group Meeting was analyzed to identify specific projects appropriate for Distribution Automation and Control DAC RD&D. Specific projects that should be undertaken in the DAC RD&D program were recommended. The projects are presented under broad categories of work selected based on ESC's interpretation of the results of the Working Group Meeting. Some of the projects are noted as utility industry projects. The ESC recommendations regarding program management are presented. Utility versus Government management responsibilities are noted.
Soil erosion potential of reclaimed mined lands
D. M. Hartley; G. E. Schuman
Runoff and erosion from three mulch treatments were measured on a surface coal mine near Hanna, Wyoming. Treatments included no mulch, standing grain mulch and crimped straw mulch. Treatments were subjected to artificial rainfall generated by a portable rainfall simulator during three successive growing seasons. Soil loss data indicate a peak in erosion hazard during the summer following seeding of
Past, Present, Future Erosion at Locke Island
Bjornstad, Bruce N.
This report describes and documents the erosion that has occurred along the northeast side of Locke Island over the last 10 to 20 years. The principal cause of this erosion is the massive Locke Island landslide complex opposite the Columbia River along the White Bluffs, which constricts the flow of the river and deflects the river's thalweg southward against the island.
Technology Transfer Automated Retrieval System (TEKTRAN)
Traditionally gully erosion has been identified with the dissection of the landscape in agricultural settings, but it is also recognized as a prevalent erosion feature in earthen dam auxiliary spillways and embankments. Flows through earthen spillways and over dam embankments, due to large rainfall...
A rangeland hydrology and erosion model
Technology Transfer Automated Retrieval System (TEKTRAN)
Soil loss rates on rangelands are considered one of the few quantitative indicators for assessing rangeland health and conservation practice effectiveness. An erosion model to predict soil loss specific for rangeland applications is needed because existing erosion models were developed from cropland...
Tools for Ephemeral Gully Erosion Process Research
Technology Transfer Automated Retrieval System (TEKTRAN)
Techniques to quantify ephemeral gully erosion have been identified by USDA Natural Resources Conservation Service (NRCS) as one of gaps in current erosion assessment tools. One reason that may have contributed to this technology gap is the difficulty to quantify changes in channel geometry to asses...
Progress and problems in erosion prediction
NASA Technical Reports Server (NTRS)
Heymann, F. J.
Methods for predicting erosion resulting from repeated localized impulsive loadings, such a impacts from droplets or in cavitation flow from microjets and bubbles, are examined. The parameters which determine the adequacy of a component to resist the loads put upon it are identified. The development of erosion rate models is discussed. The expected accuracy of the prediction and the sources of error are analyzed.
Bile-induced acute erosive gastritis
N. S. Mann
Intragastric administration of whole bile-produced acute erosive gastritis in rats. Concomitant intragastric administration of prostaglandin E2, Cholestyramine and an antacid (Maalox) was effective in preventing this type of acute erosive gastritis. The protective effect of prostaglandin E2- in this regard was significantly more marked as compared to Cholestyramine and Maalox.
This report describes the development and initial testing of the Watershed Erosion and Sediment Transport (WEST) Model. It is a deterministic conceptual model which operates in two phases. In the first one, hydrological and erosion processes associated with the land surfaces of a...
Potential for seepage erosion of landslide dam
Meyer, W.; Schuster, R.L.; Sabol, M.A.
The failure potential of the debris-avalanche dam at Castle Lake near Mount St. Helens, Washington, by three processes of seepage erosion (1) Heave; (2) piping; and (3) internal erosion, is examined. Results indicated that the dam is stable against piping but potentially locally unstable against heave. -from Authors
Improvement in the control aspect of laser frequency stabilization for SUNLITE project
NASA Technical Reports Server (NTRS)
Zia, Omar
Flight Electronics Division of Langley Research Center is developing a spaceflight experiment called the Stanford University and NASA Laser In-Space Technology (SUNLITE). The objective of the project is to explore the fundamental limits on frequency stability using an FM laser locking technique on a Nd:YAG non-planar ring (free-running linewidth of 5 KHz) oscillator in the vibration free, microgravity environment of space. Compact and automated actively stabilized terahertz laser oscillators will operate in space with an expected linewidth of less than 3 Hz. To implement and verify this experiment, NASA engineers have designed and built a state of the art, space qualified high speed data acquisition system for measuring the linewidth and stability limits of a laser oscillator. In order to achieve greater stability and better performance, an active frequency control scheme requiring the use of a feedback control loop has been applied. In the summer of 1991, the application of control theory in active frequency control as a frequency stabilization technique was investigated. The results and findings were presented in 1992 at the American Control Conference in Chicago, and have been published in Conference Proceedings. The main focus was to seek further improvement in the overall performance of the system by replacing the analogue controller by a digital algorithm.
An experimental comparison of gross and net erosion of Mo in the DIII-D divertor
NASA Astrophysics Data System (ADS)
Stangeby, P. C.; Rudakov, D. L.; Wampler, W. R.; Brooks, J. N.; Brooks, N. H.; Buchenauer, D. A.; Elder, J. D.; Hassanein, A.; Leonard, A. W.; McLean, A. G.; Okamoto, A.; Sizyuk, T.; Watkins, J. G.; Wong, C. P. C.
Experimental observation of net erosion of molybdenum being significantly reduced compared to gross erosion in the divertor of DIII-D is reported for well-controlled plasma conditions. For the first time, gross erosion rates were measured by both spectroscopic and non-spectroscopic methods. In one experiment a net erosion rate of 0.73 ▒ 0.03 nm/s was measured using ion beam analysis (IBA) of a 1 cm diameter Mo-coated sample. For a 1 mm diameter Mo sample exposed at the same time the net erosion rate was higher at 1.31 nm/s. For the small sample redeposition is expected to be negligible in comparison with the larger sample yielding a net to gross erosion estimate of 0.56 ▒ 12%. The gross rate was also measured spectroscopically (386 nm MoI line) giving 2.45 nm/s ▒ factor 2. The experiment was modeled with the REDEP/WBC erosion/redeposition code package coupled to the ITMC-DYN mixed-material code, with plasma conditions supplied by the OEDGE code using Langmuir probe data input. The code-calculated net/gross ratio is =0.46, in good agreement with experiment.
Animal-powered tillage erosion assessment in the southern Andes region of Ecuador
NASA Astrophysics Data System (ADS)
Dercon, G.; Govers, G.; Poesen, J.; Sßnchez, H.; Rombaut, K.; Vandenbroeck, E.; Loaiza, G.; Deckers, J.
While water erosion has been the focus of past research in the Andes, former studies show that soil erosion could also be related to the methods used in cultivating the fields. The main objective of the present study was to assess (i) tillage erosion caused by the traditional animal-powered "yunta" or ard plough in the Andes and the factors controlling the process and (ii) the implications for soil conservation. Erosion rates were experimentally measured on 27 sites, having slopes from ca. 0% to 60% and soils ranging from Andosols to Cambisols, in the Andes region of Ecuador (Gima, Azuay). Different tillage methods were assessed: (i) tillage parallel to the contour lines ('Paralelo') and (ii) tillage at an angle with the contour lines. Statistical analysis points out that erosion caused by animal-powered tillage is gravity-driven. A strong correlation exists between slope and downslope displacement: furthermore, tillage depth and initial soil condition are important. For the 'Paralelo' tillage method the tillage transportation coefficient ( k) is below 100 kg m - 1 Tillage Pass - 1 , for the combined 'Arado'-'Cruzado' tillage method k may exceed 300 kg m - 1 . Tillage erosion is responsible for the reduction of the slope between the contour strips over a relatively short time period of 20 years, resulting in the formation of terraces and therefore the reduction of the water erosion risk. However, at the same time it may negatively affect soil quality.
Improvement in cavitation erosion resistance of AISI 316L stainless steel by friction stir processing
NASA Astrophysics Data System (ADS)
Hajian, M.; Abdollah-zadeh, A.; Rezaei-Nejad, S. S.; Assadi, H.; Hadavi, S. M. M.; Chung, K.; Shokouhimehr, M.
Commercial AISI 316L plates with the initial grain size of 14.8 ?m were friction stir processed (FSP) with different processing parameters, resulting in two fine-grained microstructures with the grain sizes of 4.6 and 1.7 ?m. The cavitation erosion behavior, before and after FSP, was evaluated in terms of incubation time, cumulative mass loss and mean depth of erosion. A separate cavitation erosion test was performed on the transverse cross section of a FSP sample to reveal the effect of grain structure. It was observed that FSP samples, depending on their grain size, are at least 3-6 times more resistant than the base material against cavitation erosion. The improvement in cavitation erosion resistance is attributed to smaller grain structure, lower fraction of twin boundaries, and favorable crystallographic orientation of grains in FSP samples. The finer the grain size, the more cavitation erosion resistance was achieved. Moreover, the microstructures of eroded surfaces were studied using a scanning electron microscope equipped with EBSD, and an atomic force microscope. The mechanisms controlling the cavitation erosion damage in friction stir processed AISI 316L are also discussed.
Effect of Rainfall-moving Direction on Slope Runoff and Soil Erosion
NASA Astrophysics Data System (ADS)
Wang, F.; Ran, Q.
Although topographic characteristics is one of the factors controlling hillslope erosion, the current understanding of the impacts of rainfall-moving direction is far from thorough. In this study, a series of laboratory experiments were conducted to evaluate the effect of rainfall-moving direction and rainfall intensity on runoff generation and soil erosion.3D laser scanner were also used to monitor the slope surface changing. Runoff and sediment samples were taken at 1-min intervals. The results showed that there is one peak sediment concentration in upstream-moving rainfall events but two in downstream-moving rainfall events. Surface sealing greatly affected the sediment grading at the beginning of runoff, which results in less soil erosion. Because of the fully developed crust, the discharge peak occurred after the erosion peak in upstream-moving rainfall events, while two peaks occurred at the same time in downstream conditions. The erosion of downstream moving rainfall events were higher than upstream moving rainfall events under same condition. This study give a better understanding of hillslope erosion and crust development, which will improve the technology of water and soil conservation and numerical erosion simulation
Cumulative Effective Stream Power and Bank Erosion on the Sacramento River, California, USA
NASA Astrophysics Data System (ADS)
Larsen, Eric W.; Fremier, Alexander K.; Greco, Steven E.
Bank erosion along a river channel determines the pattern of channel migration. Lateral channel migration in large alluvial rivers creates new floodplain land that is essential for riparian vegetation to get established. Migration also erodes existing riparian, agricultural, and urban lands, sometimes damaging human infrastructure (e.g., scouring bridge foundations and endangering pumping facilities) in the process. Understanding what controls the rate of bank erosion and associated point bar deposition is necessary to manage large alluvial rivers effectively. In this study, bank erosion was proportionally related to the magnitude of stream power. Linear regressions were used to correlate the cumulative stream power, above a lower flow threshold, with rates of bank erosion at 13 sites on the middle Sacramento River in California. Two forms of data were used: aerial photography and field data. Each analysis showed that bank erosion and cumulative effective stream power were significantly correlated and that a lower flow threshold improves the statistical relationship in this system. These correlations demonstrate that land managers and others can relate rates of bank erosion to the daily flow rates of a river. Such relationships can provide information concerning ecological restoration of floodplains related to channel migration rates as well as planning that requires knowledge of the relationship between flow rates and bank erosion rates.
Quantifying Ground-Water Savings Achieved by Salt-Cedar Control Measures: A Demonstration Project
NASA Astrophysics Data System (ADS)
Butler, J. J.; Kluitenberg, G. J.; Whittemore, D. O.; Healey, J. M.; Zhan, X.
Consumption of ground water by phreatophytes in riparian corridors is thought to be one factor responsible for stream-flow reductions in western Kansas and elsewhere. Extensive phreatophyte-control measures, primarily focusing on invasive species such as salt cedar and Russian olive, are being considered in response to concerns about the impact of phreatophytes on surface-and ground-water resources. At present, there is no generally accepted means of quantifying the ground-water savings that might be gained through these control measures. Micrometeorological methods are often not appropriate for this application because their fetch requirements are too large for narrow riparian corridors. Recently, an approach based on diurnal fluctuations in the water table has been shown to have potential for quantifying ground-water consumption by phreatophytes. A demonstration project is underway to examine the utility of this method for assessing ground-water savings achieved through phreatophyte-control measures. This project is being carried out at a research site in a region of salt-cedar infestation along the Cimarron River in southwestern Kansas. The site has been subdivided into four areas of approximately four hectares each in which different salt-cedar control measures will be applied. Control measures will not be used in one area so that data unaffected by those measures can be obtained throughout the project. Wells equipped with submersible pressure sensors have been installed to monitor water-table responses in the vicinity of the most common phreatophyte communities at the site. A neutron access tube has been emplaced adjacent to each well so that water content in the vadose zone can also be monitored. Changes in water-content profiles will be used to estimate specific yield, a critical parameter in the proposed methodology. A weather station has also been installed on site to monitor meteorological conditions and provide reference ET estimates. Water-level data collected prior to any control activities clearly indicate that the magnitude of the water-table fluctuations is highly dependent on the apparent vitality of the phreatophyte community in the vicinity of each well. After the control measures have been applied, water-level data from the treated areas will be compared to data from the untreated area. That comparison should enable quantification of reductions in ground-water consumption produced by those measures.
Erosion testing of hard materials and coatings
Hawk, Jeffrey A.
Erosion is the process by which unconstrained particles, usually hard, impact a surface, creating damage that leads to material removal and component failure. These particles are usually very small and entrained in fluid of some type, typically air. The damage that occurs as a result of erosion depends on the size of the particles, their physical characteristics, the velocity of the particle/fluid stream, and their angle of impact on the surface of interest. This talk will discuss the basics of jet erosion testing of hard materials, composites and coatings. The standard test methods will be discussed as well as alternative approaches to determining the erosion rate of materials. The damage that occurs will be characterized in genera1 terms, and examples will be presented for the erosion behavior of hard materials and coatings (both thick and thin).
33 CFR 263.23 - Small flood control project authority (Section 205).
Code of Federal Regulations, 2012 CFR
...viability of the plan and the attainment of benefits from the plan. Consideration of land enhancement shall be in accordance with EM 1120-2-109. (e) Limitation on erosion protection. This authority shall not be used for protecting against bank...
Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Current and advanced act control system definition study. Volume 2: Appendices
NASA Technical Reports Server (NTRS)
Hanks, G. W.; Shomber, H. A.; Dethman, H. A.; Gratzer, L. B.; Maeshiro, A.; Gangsaas, D.; Blight, J. D.; Buchan, S. M.; Crumb, C. B.; Dorwart, R. J.
The current status of the Active Controls Technology (ACT) for the advanced subsonic transport project is investigated through analysis of the systems technical data. Control systems technologies under examination include computerized reliability analysis, pitch axis fly by wire actuator, flaperon actuation system design trade study, control law synthesis and analysis, flutter mode control and gust load alleviation analysis, and implementation of alternative ACT systems. Extensive analysis of the computer techniques involved in each system is included.
Erosion rates along fault scarps and rift-shoulder environments in central and northern Kenya: Insights from new 10Be-derived basin-wide erosion rates
NASA Astrophysics Data System (ADS)
Torres-Acosta, V.; Strecker, M. R.; Schildgen, T. F.; Wittmann, H.; Scherler, D.; Bookhagen, B.
The Kenya Rift is typical example of an active continental rift zone and is a fundamental part of the East African Rift system. The rift valley plays a central role in archiving the relationships between sedimentation, erosion, and climate in the region. However, the links between surface processes (i.e., erosion, sedimentation) and tectonic setting are currently poorly understood. In this study we analyze to what degree tectono-geomorphic setting and/or climatic characteristics control erosion rates in the region. We extract morphometric characteristics of the rift flanks and the plateau surface from SRTM 90-m resolution digital elevation data. We rely on calibrated, satellite-derived Tropical Rainfall Measurement Mission (TRMM 2B31) rainfall to characterize the different climatic compartments throughout the study region. We calculate specific stream power amounts using integrated rainfall as discharge amounts. Next, we analyze the relation between cosmogenic radionuclide (CRN) basin-wide erosion rates and climatic and geomorphic parameters. We determined erosion rates from twenty-six river sand samples acquired from along the flanks of the Elgeyo Escarpment (northern section of western rift flank), the Nguruman Escarpment (southern section of western flank), the Tirr Tirr Plateau (north), the Kapute Plains, and the Suguta Valley. Catchment-wide erosion rates range from 0.001 to 0.1 mm/y across the different climatic compartments. Comparisons to catchment climate and topographic characteristics suggest that more than 60% of variation in erosion can be explain by specific stream power amounts using rainfall as discharge component. The catchment-averaged normalized channel steepness index, which doesn't take into account variations in precipitation, explains only 42% of the variation in erosion rates. These observations demonstrate that the strong spatial variations in erosion rates are largely controlled by both catchment morphology and climatic gradients. In addition to our assessments of the relationships between modern erosion, precipitation, and catchment morphology, we aim to place these analyses in a broader geologic context of the evolution of the Kenya Rift. To do this, we will compare results presented here to exhumation rates derived from low-temperature thermochronology data (apatite (U-Th)/He and apatite fission track) to assess the longer-term tectonic and climatic controls on landscape evolution in this environment.
Erosion rates and erosion patterns of Neogene to Quaternary stratovolcanoes in the Western Cordillera of the Central Andes: An SRTM DEM based analysis
NASA Astrophysics Data System (ADS)
Karßtson, D.; Telbisz, T.; W÷rner, G.
Erosion patterns and rates of 33 stratovolcanoes in the arid to hyperarid Central Andean Volcanic Zone (14░S to 27░S) have been constrained by morphometric modelling. All selected volcanoes belong to the short-lived, symmetrical, circular andesitic stratocone type, with ages spanning 14 Ma to recent. Starting from the initial, youthful volcano morphology of this type, represented in our study by Parinacota volcano, and comparing reconstructed volumes of progressively eroded volcanoes, such a time span allows us to infer long-term erosion rates. Typical erosion rates of < 10 to 20 m/Ma have been obtained for the Altiplano-Puna Plateau. Lowest erosion rates typify the hyperarid Puna plateau (7-9 m/Ma), while somewhat higher values (13-22 m/Ma) are recorded for volcanoes in the more humid South Peru, suggesting climatic control on differences in erosion rates. By contrast, much higher short-term erosion rates of 112 to 66 m/Ma, decreasing with age, are found for young (Late Quaternary) volcanoes, which indicates that juvenile volcanoes erode more rapidly due to their unconsolidated cover and steeper slopes; surface denudation slows down to approximately one tenth of this after a few Ma. An inverse correlation is observed between the degree of denudation (defined as volume removed by erosion/original volume) and edifice height from base to top after erosion. This relationship is independent of climate and original edifice elevation. The degree of denudation vs. volcano age provides a rough morphometric tool to constrain the time elapsed since the extinction of volcanic activity. This method can, however, only be applied to the volcanoes of the Altiplano (i.e. under uniform, long-term arid climate) with an uncertainty of ~ 1 Ma. Finally, an erosional pathway is suggested for volcanoes of the Altiplano-Puna preserving a peculiar "edelweiss" valley pattern related to glaciations. This pattern may have overprinted previous drainages and resulted in a discontinuous height reduction of the degrading stratovolcanoes.
Measuring software development characteristics in the local environment. [considering project requirements for spacecraft control
NASA Technical Reports Server (NTRS)
Basili, V. R.; Zelkowitz, M. V.
In a brief evaluation of software-related considerations, it is found that suitable approaches for software development depend to a large degree on the characteristics of the particular project involved. An analysis is conducted of development problems in an environment in which ground support software is produced for spacecraft control. The amount of work involved is in the range from 6 to 10 man-years. Attention is given to a general project summary, a programmer/analyst survey, a component summary, a component status report, a resource summary, a change report, a computer program run analysis, aspects of data collection on a smaller scale, progress forecasting, problems of overhead, and error analysis.
Spatial variability of erosion rates inferred from the frequency distribution of cosmogenic 3He in olivines from Hawaiian river sediments
NASA Astrophysics Data System (ADS)
Gayer, Eric; Mukhopadhyay, Sujoy; Meade, Brendan J.
To constrain the spatial distribution of erosion rates in the Waimea river watershed, on the western side of the island of Kauai, Hawaii, we calculate the frequency distribution of cosmogenic 3He concentrations ([ 3He] c) from helium isotopic measurements in olivine grains from a single sample of river sediment. Helium measurements were made in 26 aliquots of ś 30 olivine grains each. The average [ 3He] c from the 26 aliquots was used to estimate a basin-wide average erosion rate of 0.056 mm/yr, a value that is similar to erosion rates obtained from geochemical analyses of river sediments from tectonically stable landforms. However, forward models of cosmogenic nuclide production and sediment generation rates are inconsistent with the hypothesis that the observed [ 3He] c frequency distribution is the result of a homogeneous, basin wide, erosion rate. Instead, a distribution of erosion rates, from ś 0 to 4 mm/yr, may account for the observed frequency distribution. The distribution of erosion rates can be modeled by both non-linear slope- and curvature-dependent erosion rates with power law exponents ranging from 2.0 to 2.5. However, the spatial distribution of cosmogenic nuclides for slope- and curvature-dependent erosion rates are distinct, and we propose strategies to test further the extent to which erosion rates are controlled by the macroscale topographic features. These results demonstrate that the observed frequency distribution of cosmogenic nuclide concentrations in river sediments, combined with numerical modeling of erosion rates, can provide constraints on both the spatial variability of erosion rates in a drainage basin and the form of parameterized erosion laws.
Widespread late Cenozoic increase in erosion rates across the interior of eastern Tibet constrained by detrital low-temperature thermochronometry
NASA Astrophysics Data System (ADS)
Duvall, Alison R.; Clark, Marin K.; Avdeev, Boris; Farley, Kenneth A.; Chen, Zhengwei
New detrital low-temperature thermochronometry provides estimates of long-term erosion rates and the timing of initiation of river incision from across the interior of the Tibetan Plateau. We use the erosion history of this region to evaluate proposed models of orogenic development as well as regional climatic events. Erosion histories of the externally drained portion of the east-central Tibetan Plateau are recorded in modern river sands from major rivers across a transect that spans >750 km and covers a region with no published thermochronometric ages. Individual grains from eight catchments were analyzed for apatite (U-Th)/He and fission track thermochronometry. A wide distribution in ages that, in most cases, spans the entire Cenozoic and Late Mesozoic eras requires a long period of slow or no erosion with a relative increase in erosion rate toward the present. We apply a recently developed methodology for inversion of detrital thermochronometric data for three specified erosion scenarios: constant erosion rate, two-stage erosion history, and three-stage erosion history. Modeling results suggest that rates increase by at least an order of magnitude between 11 and 4 Ma following a period of slow erosion across the studied catchments. Synchroneity in accelerated erosion across the whole of the Tibetan Plateau rather than a spatial or temporal progression challenges the widely held notion that the plateau evolved as a steep, northward-propagating topographic front, or that south to north precipitation gradients exert a primary control on erosion rates. Instead, we suggest that accelerated river incision late in the orogen's history relates to regional-scale uplift that occurred in concert with eastern expansion of the plateau.
Southwest Washington coastal erosion workshop report 2000
Gelfenbaum, Guy, (Edited By); Kaminsky, George M.
This report is a compilation of abstracts that correspond to oral presentations and posters presented at the fifth principal investigators workshop of the Southwest Washington Coastal Erosion Study. The workshop was held November 15 - 17, 2000 at the Department of Ecology headquarters building in Olympia, WA. For the fourth consecutive year in November, the workshop convened the entire multi-disciplinary group of scientists and engineers working on the Study or on related projects within the Columbia River littoral cell (CRLC) (Figures 1 and 2). The workshop participants are listed in the List of Attendees section towards the end of this report. The purpose of this workshop was to bring all Study investigators and associated engineers and scientists together to discuss recent work, ongoing tasks, and future research plans in the CRLC. Investigators were asked to present recent data, preliminary interpretations, and research results to invoke discussion and correlation with parallel scientific efforts. The abstracts compiled in this report represent a wealth of information on the CRLC, but because much of the work is in progress, the reader is advised that the information provided herein is preliminary and subject to change.
Gender Differences in Hypertension Control Among Older Korean Adults: Korean Social Life, Health, and Aging Project
Chu, Sang Hui; Baek, Ji Won; Kim, Eun Sook; Stefani, Katherine M.; Lee, Won Joon; Park, Yeong-Ran; Youm, Yoosik; Kim, Hyeon Chang
Objectives: Controlling blood pressure is a key step in reducing cardiovascular mortality in older adults. Gender differences in patientsÆ attitudes after disease diagnosis and their management of the disease have been identified. However, it is unclear whether gender differences exist in hypertension management among older adults. We hypothesized that gender differences would exist among factors associated with hypertension diagnosis and control among community-dwelling, older adults. Methods: This cross-sectional study analyzed data from 653 Koreans aged ?60 years who participated in the Korean Social Life, Health, and Aging Project. Multiple logistic regression was used to compare several variables between undiagnosed and diagnosed hypertension, and between uncontrolled and controlled hypertension. Results: Diabetes was more prevalent in men and women who had uncontrolled hypertension than those with controlled hypertension or undiagnosed hypertension. High body mass index was significantly associated with uncontrolled hypertension only in men. Multiple logistic regression analysis indicated that in women, awareness of oneÆs blood pressure level (odds ratio [OR], 2.86; p=0.003) and the number of blood pressure checkups over the previous year (OR, 1.06; p=0.011) might influence the likelihood of being diagnosed with hypertension. More highly educated women were more likely to have controlled hypertension than non-educated women (OR, 5.23; p=0.013). Conclusions: This study suggests that gender differences exist among factors associated with hypertension diagnosis and control in the study population of community-dwelling, older adults. Education-based health promotion strategies for hypertension control might be more effective in elderly women than in elderly men. Gender-specific approaches may be required to effectively control hypertension among older adults. PMID:25652709