Presidential Young Investigator Award:  Dynamic Properties  of Concentrated Suspensions (REU Supplement)
{'Code': '07020000', 'Directorate': {'Abbreviation': 'ENG', 'LongName': 'Directorate For Engineering'}, 'Division': {'Abbreviation': 'CBET', 'LongName': 'Div Of Chem, Bioeng, Env, & Transp Sys'}}
{'SignBlockName': 'Mihail Roco', 'PO_EMAI': None, 'PO_PHON': None}
Narrative: The use of concentrated suspensions of non-colloidal                 particles in such diverse applications as the flow of blood in                  arteries and artificial organs and of coal-oil slurries in mixed                fuel furnaces makes the detailed understanding of their properties              imperative.  Several aspects of the behavior exhibited by these                 types of suspensions which are, as yet, poorly understood are being             investigated.                                                                                                                                                   SHEAR INDUCED MIGRATION:                                                                                                                                        It has been shown that when concentrated suspensions of non-                    colloidal particles are sheared, the particles will drift across                streamlines due to gradients in concentration.  The mechanism                   proposed as an explanation for this migration suggests that shear               induced migration may arise from gradients in shear stress as well.             Preliminary experiments provide indirect evidence for this source of            particle drift; however, the results to date are far from                       conclusive.  Experiments aimed at proving or disproving the                     existence of migrations arising from gradients in shear stress are              being conducted.                                                                                                                                                THE EFFECT OF SURFACE ROUGHNESS ON SUSPENSION RHEOLOGY:                                                                                                         Recent work has demonstrated that the behavior of a concentrated                suspension of non-colloidal particles is critically dependent on the            surface properties of the particles.  This is primarily due to the              closeness of the approach of the particle surfaces in a suspension              undergoing shear.  Preliminary analysis suggests that the most                  significant non-Newtonian properties manifested by these suspensions            result from the presence of a small degree of surface roughness on              these particles.  Using both experimental and numerical simulation,             it is being attempted to quantify the relationship between surface              roughness and the rheological properties of concentrated                        suspensions.                                                                                                                                                    FLOW INDUCED MICROSTRUCTURE IN CONCENTRATED SUSPENSIONS:                                                                                                        The microstructure of a suspension plays a critical role in                     determining important rheological properties.  While much progress              has been made in determining the microstructure in dilute systems,              for concentrated suspensions it remains poorly understood.  A key               question that is as yet unanswered is the degree to which particles             aggregate in concentrated suspensions of non-colloidal particles.               Numerical simulations suggest that the lubrication forces between               interacting particles may lead to the formation of large structures             in concentrated suspensions; however, the formation of aggregates               should be a strong function of particle surface properties and the              existence of large aggregates has yet to be confirmed                           experimentally.  Using a novel experimental technique, it is being              attempted to determine the degree of aggregation by measuring both              the particle distribution function and particle velocity                        distribution of a concentrated suspension of non-colloidal spheres              undergoing simple shear flow.  Eventually, this study will be                   expanded to include the complete determination of the microstructure            of concentrated suspensions as a function of the flow geometry,                 particle surface properties such as surface roughness, and particle             shape.
{'FirstName': 'David', 'LastName': 'Leighton', 'PI_MID_INIT': 'T', 'PI_SUFX_NAME': None, 'PI_FULL_NAME': 'David T Leighton', 'EmailAddress': 'dtl@nd.edu', 'NSF_ID': '000242327', 'StartDate': '07/01/1987', 'EndDate': None, 'RoleCode': 'Principal Investigator'}
{'Name': 'University of Notre Dame', 'CityName': 'NOTRE DAME', 'ZipCode': '465565708', 'PhoneNumber': '5746317432', 'StreetAddress': '940 GRACE HALL', 'StreetAddress2': None, 'CountryName': 'United States', 'StateName': 'Indiana', 'StateCode': 'IN', 'CONGRESSDISTRICT': '02', 'CONGRESS_DISTRICT_ORG': 'IN02', 'ORG_UEI_NUM': 'FPU6XGFXMBE9', 'ORG_LGL_BUS_NAME': 'UNIVERSITY OF NOTRE DAME DU LAC', 'ORG_PRNT_UEI_NUM': 'FPU6XGFXMBE9'}
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[{'Code': '136000', 'Text': 'EWFD-Eng Workforce Development'}, {'Code': '141500', 'Text': 'PMP-Particul&MultiphaseProcess'}]
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