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Coagulation of Dust Particles in Argon Plasma of RF Discharge
Mankelevich, Yu. A.; Olevanov, M. A.; Pal, A. F.; Rakhimova, T. V.; Ryabinkin, A. N.; Serov, A. O. [Lomonosov Moscow State University Skobeltsyn Institute of Nuclear Physics, 1(2), Leninskie gory, GSP-1, Moscow 119991 (Russian Federation); Filippov, A. V. [Troitsk Institute for Innovation and Fusion Research, Troitsk 142190, Moscow region (Russian Federation)
The experiments on coagulation of poly-disperse particles with various size distributions injected into the argon plasma of the magnetron radio-frequency discharge are discussed. The experiments were carried out under the conditions similar to those using dusty plasma for technology applications. Within the created theory the threshold behavior of the coagulation process was explained for the first time, the estimation of the critical particle size for onset of a fast coagulation was made, and the analytical calculation of the coagulation rate of dust particles was performed. The proposed coagulation mechanism makes it possible to describe the typical features of coagulation processes observed in experiments and to explain the effects of attraction and coalescence of highly negatively charged microns size particles.
Histology assessment of bipolar coagulation and argon plasma coagulation on digestive tract
Garrido, Teresa; Baba, Elisa R; Wodak, Stephanie; Sakai, Paulo; Cecconello, Ivan; Maluf-Filho, Fauze
AIM: To analyze the effect of bipolar electrocoagulation and argon plasma coagulation on fresh specimens of gastrointestinal tract. METHODS: An experimental evaluation was performed at Hospital das Clinicas of the University of São Paulo, on 31 fresh surgical specimens using argon plasma coagulation and bipolar electrocoagulation at different time intervals. The depth of tissue damage was histopathologically analyzed by single senior pathologist unaware of the coagulation method and power setting applied. To analyze the results, the mucosa was divided in superficial mucosa (epithelial layer of the esophagus and superficial portion of the glandular layer of the stomach and colon) intermediate mucosa (until the lamina propria of the esophagus and until the bottom of the glandular layer of the stomach and colon) and muscularis mucosa. Necrosis involvement of the layers was compared in several combinations of power and time interval. RESULTS: Involvement of the intermediate mucosa of the stomach and of the muscularis mucosa of the three organs was more frequent when higher amounts of energy were used with argon plasma. In the esophagus and in the colon, injury of the intermediate mucosa was frequent, even when small amounts of energy were used. The use of bipolar electrocoagulation resulted in more frequent involvement of the intermediate mucosa and of the muscularis mucosa of the esophagus and of the colon when higher amounts of energy were used. In the stomach, these involvements were rare. The risk of injury of the muscularis propria was significant only in the colon when argon plasma coagulation was employed. CONCLUSION: Tissue damage after argon plasma coagulation is deeper than bipolar electrocoagulation. Both of them depend on the amount of energy used. PMID:25031789
Trimming a Metallic Biliary Stent Using an Argon Plasma Coagulator
Rerknimitr, Rungsun, E-mail: email@example.com; Naprasert, Pisit; Kongkam, Pradermchai; Kullavanijaya, Pinit [Faculty of Medicine, Chulalongkorn University, Gastroenterology Unit, Department of Internal Medicine (Thailand)
Background. Distal migration is one of the common complications after insertion of a covered metallic stent. Stent repositioning or removal is not always possible in every patient. Therefore, trimming using an argon plasma coagulator (APC) may be a good alternative method to solve this problem. Methods. Metallic stent trimming by APC was performed in 2 patients with biliary Wallstent migration and in another patient with esophageal Ultraflex stent migration. The power setting was 60-100 watts with an argon flow of 0.8 l/min. Observations. The procedure was successfully performed and all distal parts of the stents were removed. No significant collateral damage to the nearby mucosa was observed. Conclusions. In a patient with a distally migrated metallic stent, trimming of the stent is possible by means of an APC. This new method may be applicable to other sites of metallic stent migration.
[Anesthesia for argon plasma coagulation therapy through the tracheostomy site].
Nakamura, Shinji; Nishiyama, Tomoki; Hanaoka, Kazuo
We experienced a case of argon plasma coagulation (APC) therapy for bronchial obstruction. A 54-year-old man was scheduled for APC therapy for bronchial obstruction using bronchoscope via a tracheostoma. The patient had received left upper lobectomy four years before and laryngectomy and tracheotomy two years before. Anesthesia was induced with droperidol 2.5 mg, and gradual administration of fentanyl (total 125 microg) and midazolam (total 1 mg). Surgery was completed in 15 minutes under spontaneous breathing of air. In APC therapy, we cannot administer oxygen for fear of argon-ignited intratracheal combustion. Using small doses of droperidol, fentanyl, and midazolam, we could successfully anesthetize a patient for APC therapy through the tracheostomy site under spontaneous respiration with air. PMID:16296370
Rectal ulcer: Due to ketoprofen, argon plasma coagulation and prostatic brachytherapy.
Koessler, Thibaud; Servois, Vincent; Mariani, Pascale; Aubert, Emilie; Cacheux, Wulfran
Prostatic brachytherapy with permanent seed implants is a recent and safe radiation therapy technique associated with radiation-induced digestive disease. Argon plasma coagulation procedure is a validated modality in the management of haemorrhagic radiation proctitis, which is known to occasionally induce chronic rectal ulcers. We report here an original case report of an acute painful rectal ulcer as a consequence of the combination of short-term therapy with non-steroidal anti-inflammatory drugs therapy, prostatic brachytherapy with malposition of seed implants and argon plasma coagulation procedure in a patient with haemorrhagic radiation proctitis. The description of this clinical observation is essential to recommend the discontinuation of non-steroidal anti-inflammatory drugs therapy and the control of the position of seed implants in case of prostatic brachytherapy before argon plasma coagulation for radiation-induced proctitis. PMID:25493041
Rectal ulcer: Due to ketoprofen, argon plasma coagulation and prostatic brachytherapy
Koessler, Thibaud; Servois, Vincent; Mariani, Pascale; Aubert, Emilie; Cacheux, Wulfran
Prostatic brachytherapy with permanent seed implants is a recent and safe radiation therapy technique associated with radiation-induced digestive disease. Argon plasma coagulation procedure is a validated modality in the management of haemorrhagic radiation proctitis, which is known to occasionally induce chronic rectal ulcers. We report here an original case report of an acute painful rectal ulcer as a consequence of the combination of short-term therapy with non-steroidal anti-inflammatory drugs therapy, prostatic brachytherapy with malposition of seed implants and argon plasma coagulation procedure in a patient with haemorrhagic radiation proctitis. The description of this clinical observation is essential to recommend the discontinuation of non-steroidal anti-inflammatory drugs therapy and the control of the position of seed implants in case of prostatic brachytherapy before argon plasma coagulation for radiation-induced proctitis. PMID:25493041
Coagulation of dust grains in the plasma of an RF discharge in argon
Mankelevich, Yu. A.; Olevanov, M. A.; Pal', A. F.; Rakhimova, T. V.; Ryabinkin, A. N.; Serov, A. O. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation); Filippov, A. V. [Troitsk Institute for Innovation and Fusion Research (Russian Federation)
Results are presented from experimental studies of coagulation of dust grains of different sizes injected into a low-temperature plasma of an RF discharge in argon. A theoretical model describing the formation of dust clusters in a low-temperature plasma is developed and applied to interpret the results of experiments on the coagulation of dust grains having large negative charges. The grain size at which coagulation under the given plasma conditions is possible is estimated using the developed theory. The theoretical results are compared with the experimental data.
Argon Plasma Coagulation for Extraction of an Impacted Trapezoid Basket in the Pancreatic Duct
Purohit, Treta; Garg, Mrinal; Kulkarni, Abhijit
We performed endoscopic retrograde cholangiopancreatography (ERCP) with sphincterotomy for pancreatic stent placement on a 55-year-old woman with a dilated pancreatic duct, pancreatic duct stone, and chronic pancreatitis. During follow-up ERCP, the lithotripter traction wire fractured during electrohydraulic lithotripsy and mechanical lithotripsy. Multiple attempts using standard techniques to clear the lithotripter and stone failed. Argon plasma coagulation (APC) was used to ablate 2 of the lithotripter wires, and the lithotripter was disengaged from the stone and removed. PMID:26157943
Treatment of tracheal mucoepidermoid carcinoma by argon plasma coagulation during pregnancy.
Kesrouani, Assaad; Dabar, Georges; Rahal, Samir; Ghorra, Claude
Mucoepidermoid carcinoma of the tracheobronchial tree is a rare airway tumor (<1% of all lung tumors). In adults, the majority of primary tracheal tumors are malignant. Management during pregnancy is complex and requires weighing maternal and fetal prognosis. Reported cases describe surgical resection following cesarean section. We report the first case to be treated by Argon-Plasma Coagulation (APC) in pregnancy. A 35-year-old Caucasian woman G1P0, at 27 weeks of gestation was admitted to the emergency department because of hemoptysis and severe dyspnea. Bronchoscopy and biopsies diagnosed primary tracheal mucoepidermoid carcinoma. Following an episode of tracheal bleeding, she was intubated. After thorough explanations to the family and obtaining informed consent, therapeutic bronchoscopy, under general anesthesia using a rigid bronchoscope, was performed. The tumor was cored out with the tip of the bronchoscope and removed with an alligator forceps. The tumor bed was coagulated with APC. The obstetrical team was ready to intervene in case of maternal emergency. Immediate follow-up was good, and she left the hospital 4 days later. She delivered at 39 weeks of gestation by cesarean section because of dystocia. Five years later, the patient is doing well without any signs or symptoms of recurrence. Pediatric follow-up is normal. Argon Plasma Coagulation for treatment of mucoepidermoid tracheal carcinoma is feasible during pregnancy. Reporting this case could lead to less aggressive management of mucoepidermoid carcinoma in pregnant patients. PMID:26011218
Endoscopic trimming of an embedded distally migrated metallic rectal stent with argon plasma coagulation.
Molina-Infante, Javier; Mateos-Rodriguez, Jose Maria; Fernandez-Bermejo, Miguel; Perez-Gallardo, Belen; Hernandez-Alonso, Moises
There is little experience regarding the use of argon plasma coagulation (APC) to trim malpositioned or migrated, endoscopic, metallic, self-expanding, colorectal stents. We report a case of a distally migrated, uncovered rectal stent complicated with several ulcerations because of impaction against the rectal wall and embedment within the healthy mucosa distal to the neoplasm. Endoscopic en bloc removal was not possible because of diffuse tumoral ingrowth. By using a second generation APC device (60 W, 0.6 L/min), the stent was trimmed allowing access to the back wall, which was tailored after digging up the embedded wires with gentle traction of the stent. Complete extraction of the protruding end of the stent by a 2.5 cm, fully covered pseudoepithelization tissue, was carried out through a flexible overtube. This is the first report of APC endoscopic transection of a long embedded segment from a distally migrated colorectal stent. PMID:20393326
Effective treatment of solitary rectal ulcer syndrome using argon plasma coagulation.
Waniczek, Dariusz; Rdes, Jerzy; Rudzki, Marek K; Piecuch, Jerzy; Rubicz, Nina; Arendt, Jerzy
Solitary rectal ulcer syndrome (SRUS) is a chronic, multiform, non-cancerous disorder of the rectum, the final diagnosis of which is based upon histopathological criteria. This disorder is often accompanied by latent proctoptosis. We present a patient who (in 1996) was the first case in which argon plasma coagulation (APC) was used for SRUS treatment. In the years 2004-2005 the same patient underwent 15 APC sessions (at monthly intervals) obtaining full recovery from SRUS, although she had been treated unsuccessfully for 17 years prior to that. Six-year observation did not show any relapse. Local therapy with APC seems to be an important alternative in SRUS treatment without prolapse of the rectum and could become a basic method for bleeding treatment in SRUS. PMID:25276257
Eradication of Barrett's mucosa with argon plasma coagulation and acid suppression: immediate and mid term results
J-L Van Laethem; M Cremer; M O Peny; M Delhaye; J Devière
Background—Intestinal metaplastic mucosa in Barrett's oesophagus can be replaced by squamous epithelium after mucosal thermal ablation associated with acid suppression therapy.Aims—To assess whether restoration of squamous epithelium can be obtained after ablation of Barrett's oesophagus using argon plasma coagulation (APC) associated with proton pump inhibitor (PPI) therapy.Methods—Thirty one patients with Barrett's oesophagus received APC. Omeprazole (40 mg\\/day) was given from
Argon Plasma Coagulation Therapy Versus Topical Formalin for Intractable Rectal Bleeding and Anorectal Dysfunction After Radiation Therapy for Prostate Carcinoma
Yeoh, Eric, E-mail: firstname.lastname@example.com [Department of Radiation Oncology, Royal Adelaide Hospital, Adelaide (Australia); School of Medicine, University of Adelaide, Adelaide (Australia); Tam, William; Schoeman, Mark [School of Medicine, University of Adelaide, Adelaide (Australia); Department of Gastroenterology, Royal Adelaide Hospital, Adelaide (Australia); Moore, James; Thomas, Michelle [School of Medicine, University of Adelaide, Adelaide (Australia); Department of Colorectal Surgery, Royal Adelaide Hospital, Adelaide (Australia); Botten, Rochelle; Di Matteo, Addolorata [Department of Radiation Oncology, Royal Adelaide Hospital, Adelaide (Australia)
Purpose: To evaluate and compare the effect of argon plasma coagulation (APC) and topical formalin for intractable rectal bleeding and anorectal dysfunction associated with chronic radiation proctitis. Methods and Materials: Thirty men (median age, 72 years; range, 49-87 years) with intractable rectal bleeding (defined as ?1× per week and/or requiring blood transfusions) after radiation therapy for prostate carcinoma were randomized to treatment with APC (n=17) or topical formalin (n=13). Each patient underwent evaluations of (1) anorectal symptoms (validated questionnaires, including modified Late Effects in Normal Tissues–Subjective, Objective, Management, and Analytic and visual analogue scales for rectal bleeding); (2) anorectal motor and sensory function (manometry and graded rectal balloon distension); and (3) anal sphincteric morphology (endoanal ultrasound) before and after the treatment endpoint (defined as reduction in rectal bleeding to 1× per month or better, reduction in visual analogue scales to ?25 mm, and no longer needing blood transfusions). Results: The treatment endpoint was achieved in 94% of the APC group and 100% of the topical formalin group after a median (range) of 2 (1-5) sessions of either treatment. After a follow-up duration of 111 (29-170) months, only 1 patient in each group needed further treatment. Reductions in rectal compliance and volumes of sensory perception occurred after APC, but no effect on anorectal symptoms other than rectal bleeding was observed. There were no differences between APC and topical formalin for anorectal symptoms and function, nor for anal sphincteric morphology. Conclusions: Argon plasma coagulation and topical formalin had comparable efficacy in the durable control of rectal bleeding associated with chronic radiation proctitis but had no beneficial effect on anorectal dysfunction.
FVII Dependent Coagulation Activation in Citrated Plasma by Polymer Hydrogels
Kofinas, Peter
FVII Dependent Coagulation Activation in Citrated Plasma by Polymer Hydrogels Brendan J. Casey in this activation. Experiments utilizing coagulation factor depleted and inhibited plasmas indicated that FVII, FX a critical correlation between polymer microstructure and FVII activation. Introduction Blood coagulation
Coagulation of dust particles in a plasma
Horanyi, M.; Goertz, C.K. (Arizona Univ., Tucson (USA) Iowa Univ., Iowa City (USA))
The electrostatic charge of small dust grains in a plasma in which the temperature varies in time is discussed, pointing out that secondary electron emission might introduce charge separation. If the sign of the charge on small grains is opposite to that on big ones, enhanced coagulation can occur which will affect the size distribution of grains in a plasma. Two scenarios where this process might be relevant are considered: a hot plasma environment with temperature fluctuations and a cold plasma environment with transient heating events. The importance of the enhanced coagulation is uncertain, because the plasma parameters in grain-producing environments such as a molecular cloud or a protoplanetary disk are not known. It is possible, however, that this process is the most efficient mechanism for the growth of grains in the size range of 0.1-500 microns. 9 refs.
Coagulation of dust particles in a plasma
NASA Technical Reports Server (NTRS)
Horanyi, M.; Goertz, C. K.
The electrostatic charge of small dust grains in a plasma in which the temperature varies in time is discussed, pointing out that secondary electron emission might introduce charge separation. If the sign of the charge on small grains is opposite to that on big ones, enhanced coagulation can occur which will affect the size distribution of grains in a plasma. Two scenarios where this process might be relevant are considered: a hot plasma environment with temperature fluctuations and a cold plasma environment with transient heating events. The importance of the enhanced coagulation is uncertain, because the plasma parameters in grain-producing environments such as a molecular cloud or a protoplanetary disk are not known. It is possible, however, that this process is the most efficient mechanism for the growth of grains in the size range of 0.1-500 microns.
Coagulation Factor XIIIa Substrates in Human Plasma
Nikolajsen, Camilla Lund; Dyrlund, Thomas F.; Poulsen, Ebbe Toftgaard; Enghild, Jan J.; Scavenius, Carsten
Coagulation factor XIII (FXIII) is a transglutaminase with a well defined role in the final stages of blood coagulation. Active FXIII (FXIIIa) catalyzes the formation of ?-(?-glutamyl)lysine isopeptide bonds between specific Gln and Lys residues. The primary physiological outcome of this catalytic activity is stabilization of the fibrin clot during coagulation. The stabilization is achieved through the introduction of cross-links between fibrin monomers and through cross-linking of proteins with anti-fibrinolytic activity to fibrin. FXIIIa additionally cross-links several proteins with other functionalities to the clot. Cross-linking of proteins to the clot is generally believed to modify clot characteristics such as proteolytic susceptibility and hereby affect the outcome of tissue damage. In the present study, we use a proteomic approach in combination with transglutaminase-specific labeling to identify FXIIIa plasma protein substrates and their reactive residues. The results revealed a total of 147 FXIIIa substrates, of which 132 have not previously been described. We confirm that 48 of the FXIIIa substrates were indeed incorporated into the insoluble fibrin clot during the coagulation of plasma. The identified substrates are involved in, among other activities, complement activation, coagulation, inflammatory and immune responses, and extracellular matrix organization. PMID:24443567
Nanoparticle coagulation in fractionally charged and charge fluctuating dusty plasmas
Nunomura, Shota; Kondo, Michio [Research Center for Photovoltaics, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568 (Japan); Shiratani, Masaharu; Koga, Kazunori; Watanabe, Yukio [Department of Electronics, Graduate School of Information Science and Electrical Engineering, Kyushu University, Fukuoka 819-0395 (Japan)
The kinetics of nanoparticle coagulation has been studied in fractionally charged and charge fluctuating dusty plasmas. The coagulation occurs when the mutual collision frequency among nanoparticles exceeds their charging and decharging/neutralization frequency. Interestingly, the coagulation is suppressed while a fraction (several percent) of nanoparticles are negatively charged in a plasma, in which stochastic charging plays an important role. A model is developed to predict a phase diagram of the coagulation and its suppression.
Plasma parameters in 40 MHz Argon discharge
NASA Astrophysics Data System (ADS)
Azooz, A. A.; Cakir, S.; Bleej, D. A.
Experimental data related to 40 MHz Argon plasma parameters in the RF power and pressure ranges of 25-200 W and 0.2-0.5 Torr are presented. Electron temperatures are obtained using both double probe and optical spectroscopy methods. Acceptable consistency between results is obtained. Double probe method is also used to obtain the plasma electron density. At any particular pressure value, the effect of increasing RF power seems to be restricted to increasing plasma electron density rather than affecting the plasma electron temperatures. Signature of the Paschen law effect is reflected on the relation between pressure and electron plasma density.
Diamond film growth argon-carbon plasmas
Gruen, Dieter M. (Downers Grove, IL); Krauss, Alan R. (Naperville, IL); Liu, Shengzhong (Canton, MI); Pan, Xianzheng (Wuhan Hubei, CN); Zuiker, Christopher D. (LaGrange, IL)
A method and system for manufacturing diamond film. The method involves forming a carbonaceous vapor, providing a gas stream of argon, hydrogen and hydrocarbon and combining the gas with the carbonaceous vapor, passing the combined carbonaceous vapor and gas carrier stream into a chamber, forming a plasma in the chamber causing fragmentation of the carbonaceous and deposition of a diamond film on a substrate.
Contact activation of blood-plasma coagulation
NASA Astrophysics Data System (ADS)
Golas, Avantika
Surface engineering of biomaterials with improved hemocompatibility is an imperative, given the widespread global need for cardiovascular devices. Research summarized in this dissertation focuses on contact activation of FXII in buffer and blood plasma frequently referred to as autoactivation. The extant theory of contact activation imparts FXII autoactivation ability to negatively charged, hydrophilic surfaces. According to this theory, contact activation of plasma involves assembly of proteins comprising an "activation complex" on activating surfaces mediated by specific chemical interactions between complex proteins and the surface. This work has made key discoveries that significantly improve our core understanding of contact activation and unravel the existing paradigm of plasma coagulation. It is shown herein that contact activation of blood factor XII (FXII, Hageman factor) in neat-buffer solution exhibits a parabolic profile when scaled as a function of silanized-glass-particle activator surface energy (measured as advancing water adhesion tension t°a=g° Iv costheta in dyne/cm, where g°Iv is water interfacial tension in dyne/cm and theta is the advancing contact angle). Nearly equal activation is observed at the extremes of activator water-wetting properties --36 < t°a < 72 dyne/cm (O° ? theta < 120°), falling sharply through a broad minimum within the 20 < t°a < 40 dyne/cm (55° < theta < 75°). Furthermore, contact activation of FXII in buffer solution produces an ensemble of protein fragments exhibiting either procoagulant properties in plasma (proteolysis of blood factor XI or prekallikrein), amidolytic properties (cleavage of s-2302 chromogen), or the ability to suppress autoactivation through currently unknown biochemistry. The relative proportions of these fragments depend on activator surface chemistry/energy. We have also discovered that contact activation is moderated by adsorption of plasma proteins unrelated to coagulation through an "adsorption-dilution" effect that blocks FXII contact with hydrophobic activator surfaces. The adsorption-dilution effect explains the apparent specificity for hydrophilic activators pursued by earlier investigators. Finally a comparison of FXII autoactivation in buffer, serum, protein cocktail, and plasma solutions is shown herein. Activation of blood plasma coagulation in vitro by contact with material surfaces is demonstrably dependent on plasma-volume-to-activator-surface-area ratio. However, activation of factor XII dissolved in buffer, protein cocktail, heat-denatured serum, and FXI deficient plasma does not exhibit activator surface-area dependence. Instead, a highly-variable burst of procoagulant-enzyme yield is measured that exhibits no measurable kinetics, sensitivity to mixing, or solution-temperature dependence. Thus, FXII activation in both buffer and protein-containing solutions does not exhibit characteristics of a biochemical reaction but rather appears to be a "mechanochemical" reaction induced by FXII molecule interactions with hydrophilic activator particles that do not formally adsorb blood proteins from solution. Results strongly suggest that activator surface-area dependence observed in contact activation of plasma coagulation does not solely arise at the FXII activation step of the intrinsic pathway.
Transition radiation energy loss in inductively coupled argon plasma
Yuping Ren; J. D. Long; S. Xu
This work studies the transition radiation energy loss in inductively coupled argon plasma. Energy loss channels due to ionization, momentum transfer, and radiation are investigated in argon plasma bounded by a cylindrical metal vessel. Radiation energy is calculated using the electron energy distribution function diagnosed by a Langmuir probe and the emission cross section. The measured electron energy is found
Neutral density profiles in argon helicon plasmas
Amy M. Keesee
A diode laser-based laser-induced fluorescence (LIF) diagnostic has been developed that can measure three species; argon neutrals, argon ions, and helium neutrals. This diagnostic has been combined with passive emission spectroscopy and a neutral argon collisional-radiative (CR) model to measure ground state radial density profiles of argon atoms in a helicon source. We have found the ground state neutral argon
Characterization and literature review of bowel perforation injuring using argon beam coagulation
NASA Astrophysics Data System (ADS)
Barnes, Kelli S.; Merchel, Renée. A.; Taylor, Kenneth D.
INTRODUCTION: Argon Beam Coagulation (ABC®) technology is used in conjunction with the ConMed ABCFlex® Probe to provide non-contact hemostasis, coagulation, and tissue devitalization during endoscopic procedures. ABC provides a superficial tissue effect; however, there is a risk of bowel perforation. To better understand the settings that lead to perforation, this study reviews the literature and provides an ex vivo characterization of the ABCFlex Probe tissue effect at different settings when used at small distances. METHODS: Depth of thermal tissue effect was characterized to determine the effect of three parameters: power (W), distance from probe tip to tissue (mm) and application duration (s). 3 ABCFlex Probes were used to create 15 samples on ex vivo porcine small intestine for each combination of parameters. The depth of tissue effect for each sample was measured using a light microscope. RESULTS: Depth of tissue effect increases as power and application time increases. An increase of distance from the probe tip to the tissue results in a decrease in depth of tissue effect from a near contact to 1mm distance. Depth of tissue effect doesn't significantly change from 1mm to 3mm distance. CONCLUSION: ABCFlex Probe can be used to achieve hemostasis in endoscopic procedures. Increasing power and application time increases the depth of thermal effect while increasing distance from the probe time to the surface of the tissue decreases the depth of tissue effect.
[Treatment of diffuse diabetic maculopathy with "grid pattern argon laser coagulation"].
Nawrocki, J; Nawrocka, Z; Swietliczko, I
Sixty eyes of 42 patients with diffuse diabetic macula edema were treated with argon laser in a "grid pattern" mode. The eyes were divided into three groups according to the preoperative visual acuity. In the first group with a preoperative visual acuity of below 0.1 (23 eyes), after 6 months of follow-up, 5 eyes improved in function by at least two lines on a Snellen chart. In the second group with an initial visual acuity of 0.2-0.4 (20 eyes) 5 eyes showed improvement and in the group with a pretreatment visual acuity of 0.5 or more (17 eyes) 6 eyes improved in function. In the first group, the visual acuity did not worsen; in the second group it worsened in 4 eyes. Two eyes in the third group showed a worse visual acuity after treatment. Similar results were found after 1 year of follow-up (27 eyes). After a 2-year follow-up (13 eyes) 9 eyes had a stable visual acuity compared to the preoperative visual acuity. Even though the number of cases with a long follow-up was relatively small, our results show clearly that early application of argon laser coagulation for diffuse macular edema allows stabilization to be achieved and, in some cases, even improvement in the visual acuity. PMID:1786914
Line ratio diagnostics in helium and helium seeded argon plasmas
R F Boivin; S D Loch; C P Ballance; D Branscomb; M S Pindzola
We investigate the potential use of line ratio diagnostics to evaluate electron temperature in either helium or helium seeded argon plasmas. Plasmas are produced in a helicon plasma source. A rf compensated Langmuir probe is used to measure both the electron temperature and plasma density while a spectrometer is used to measure He I line intensities from the plasma. For
ECR Plasma Sterilisation, Argon and Nitrogen Treated Plasma
NASA Astrophysics Data System (ADS)
Helhel, Selcuk; Oksuz, Lutfi; Cerezci, Osman; Rad, Abbas Y.
ECR type plasma system was built to produce plasma in axial direction. Plasma was initiated in a specially designed Nickel - Chrome cylindrical vacuum tube which is being driven through dielectric window by 2.45GHz commercial magnetron source. Tube is also surrounded by a coil driving 150ADC to generate approximately 875Gauss magnetic field at the center. Langmuir probe and ICCD for optical spectrometry were used to characterize internal parameters like electron density, electron temperature and different characteristics of the plasma. Bacillus Subtilis var nigar, bacillus Stearothermophilus, bacillus pumilus E601, Escherichia coli and staphylococcus aureus type bacteria were selected as a reference. Each is resistant for different actions while the Bacilus cereus is the most resistant bacteria for microwave interaction. This study presents the effect of system on used bacteria. Those are gram positive and gram negative bacteria that refers to structure of cell wall. The sterilization efficacy of Argon type ECR plasma was found to be over 99, 5% in Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis (vegetative cell), Bacillus cereus (vegetative cell), Bacillus pumilus and Escherichia coli. System response type is less than 2 minutes.
Properties of radio-frequency heated argon confined uranium plasmas
NASA Technical Reports Server (NTRS)
Pure uranium hexafluoride (UF6) was injected into an argon confined, steady state, rf-heated plasma within a fused silica peripheral wall test chamber. Exploratory tests conducted using an 80 kW rf facility and different test chamber flow configurations permitted selection of the configuration demonstrating the best confinement characteristics and minimum uranium compound wall coating. The overall test results demonstrated applicable flow schemes and associated diagnostic techniques were developed for the fluid mechanical confinement and characterization of uranium within an rf plasma discharge when pure UF6 is injected for long test times into an argon-confined, high-temperature, high-pressure, rf-heated plasma.
Electron temperature measurements in an argon\\/cesium plasma diode
Michael J. Ward
Line intensity measurements in an argon\\/cesium plasma diode were made at various locations within the discharge, yielding a spatially resolved electron temperature distribution. This device operated at 0.9 Torr argon, 0.04 Torr cesium, and at a current density of 1.05 mA\\/sq cm. Observations of the spectral line intensities of the 6P greater than nS and 6P greater than nD transitions
Effect of argon addition on plasma parameters and dust charging in hydrogen plasma
Kakati, B., E-mail: firstname.lastname@example.com; Kausik, S. S.; Saikia, B. K. [Centre of Plasma Physics-Institute for Plasma Research, Nazirakhat, Sonapur, Kamrup 782402, Assam (India); Bandyopadhyay, M.; Saxena, Y. C. [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India)
Experimental results on effect of adding argon gas to hydrogen plasma in a multi-cusp dusty plasma device are reported. Addition of argon modifies plasma density, electron temperature, degree of hydrogen dissociation, dust current as well as dust charge. From the dust charging profile, it is observed that the dust current and dust charge decrease significantly up to 40% addition of argon flow rate in hydrogen plasma. But beyond 40% of argon flow rate, the changes in dust current and dust charge are insignificant. Results show that the addition of argon to hydrogen plasma in a dusty plasma device can be used as a tool to control the dust charging in a low pressure dusty plasma.
The influence of riboflavin photochemistry on plasma coagulation factors
Larrea, Luis; Calabuig, María; Roldán, Vanesa; Rivera, José; Tsai, Han-Mou; Vicente, Vicente; Roig, Roberto
Studies with riboflavin in the 1960s showed that it could be effective at inactivating pathogens when exposed to light. The principal mode of action is through electron transfer reactions, most importantly in nucleic acids. This suggested that it could act as a photosensitizer useful in the inactivation of pathogens found in blood products. Objective To study the influence of photo-inactivation with riboflavin on the coagulation factors of plasma. Methods The photo-inactivation procedure of riboflavin plus light was applied. Fifty isogroup pools of two plasmas were made from 100 U of plasma that were derived from whole blood products that had previously been held overnight. Pools were split into two bags. One of them was photo-inactivated, and post inactivation samples were obtained. The second bag was not photo-inactivated and samples were taken. Total protein, fibrinogen, FII, FV, FVII, FVIII, FIX, FX, FXI, FXIII, antithrombin III, PC, PS, ?-2 antiplasmin and vWF:Ag, the multimeric structure of vWF and ADAMTS-13 were analyzed. Results In plasma, the proteins most sensitive to photo-inactivation were fibrinogen, FXI, FVIII, FV, and FIX (33%, 32%, 30%, 18% and 18% loss, respectively). Coagulation inhibitors, PS, antithrombin III and PC showed little decrease (all 2%). Retention of vWF and ADAMTS-13 were 99% and 88%, respectively. Conclusions As with other pathogen reduction procedures for plasma products, treatment with riboflavin and UV light resulted in reduction in the activity levels of several pro-coagulant factors. Coagulation inhibitors are well preserved. PMID:19782644
Generation of argon-ion mixed silicon plasmas forming argon encapsulated silicon clusters
T. Kaneko; H. Takaya; R. Hatakeyama
An inductively coupled argon (Ar) plasma is superimposed on a silicon (Si) plasma generated by an electron beam gun in order to realize the formation of gas-atom encapsulated Si cage clusters. The Si clusters, which are formed and deposited on a substrate, are analyzed by laser-desorption time-of-flight mass spectrometry and are found to have the mass spectra of not only
Argon and Arcal.37 plasma characteristics in a TIG configuration
NASA Astrophysics Data System (ADS)
Mougenot, J.; Gonzalez, J. J.; Freton, P.; Cressault, Y.
In a previous paper (Mougenot 2013 J. Phys. D: Appl. Phys. 46 135206), a 3D model based on the @Saturne software was presented in argon gas and the results compared with the literature results. This paper extends the analysis from pure argon and shows the influence of added helium on plasma and weld pool properties. The influence of vapours coming from the plasma interaction with the anode material is shown in Arcal.37 gas (composed of 30% argon and 70% helium), showing the necessity to consider their presence. The importance of the forces acting on the weld pool is illustrated and analysed. The Marangoni effect is the major force acting on the weld pool leading to plasma cooling, an increase in the width of the weld pool and a reduction in its depth.
Behavior of Excited Argon Atoms in Inductively Driven Plasmas
Laser induced fluorescence has been used to measure the spatial distribution of the two lowest energy argon excited states, 1s{sub 5} and 1s{sub 4}, in inductively driven plasmas containing argon, chlorine and boron trichloride. The behavior of the two energy levels with plasma conditions was significantly different, probably because the 1s{sub 5} level is metastable and the 1s{sub 4} level is radiatively coupled to the ground state but is radiation trapped. The argon data is compared with a global model to identify the relative importance of processes such as electron collisional mixing and radiation trapping. The trends in the data suggest that both processes play a major role in determining the excited state density. At lower rfpower and pressure, excited state spatial distributions in pure argon were peaked in the center of the discharge, with an approximately Gaussian profile. However, for the highest rfpowers and pressures investigated, the spatial distributions tended to flatten in the center of the discharge while the density at the edge of the discharge was unaffected. The spatially resolved excited state density measurements were combined with previous line integrated measurements in the same discharge geometry to derive spatially resolved, absolute densities of the 1s{sub 5} and 1s{sub 4} argon excited states and gas temperature spatial distributions. Fluorescence lifetime was a strong fi.mction of the rf power, pressure, argon fraction and spatial location. Increasing the power or pressure resulted in a factor of two decrease in the fluorescence lifetime while adding Cl{sub 2} or BCl{sub 3} increased the fluorescence lifetime. Excited state quenching rates are derived from the data. When Cl{sub 2} or BCl{sub 3} was added to the plasma, the maximum argon metastable density depended on the gas and ratio. When chlorine was added to the argon plasma, the spatial density profiles were independent of chlorine fraction. While it is energetically possible for argon excited states to dissociate some of the molecular species present in this discharge, it does not appear to be a significant source of dissociation. The major source of interaction between the argon and the molecular species BCl{sub 3} and Cl{sub 2} appears to be through modification of the electron density.
This chapter reports on the efforts of the USEPA to study conventional and enhanced coagulation for the control of disinfection by-products (DBPs) in drinking water. It examines the control of DBPs like trihalomethanes, haloacetic acids and the surrogate total organic halide in t...
Transport coefficients of helium and argon-helium plasmas
Anthony B. Murphy
Calculated values of the viscosity, thermal conductivity, and electrical conductivity of helium, and mixtures of argon and helium, at high temperatures are presented. In addition, combined ordinary, pressure, and thermal diffusion coefficients are given for the mixtures. The calculations, which assume local thermodynamic equilibrium, are performed for atmospheric pressure plasmas in the temperature range from 300 to 30000 K. The
Supersonic Argon Flow In An Arc Plasma Source
Izrar, B.; Dudeck, M. [Laboratoire d'Aerothermique, 1C avenue de la Recherche Scientifique, 45071 Orleans cedex (France); Andre, P. [Laboratoire des Arc Electriques et des Plasmas Thermiques, LAEPT, Universite Blaise Pascal, 24 av. des landais, 63177 Aubiere cedex (France); Elchinger, M. F.; Aubreton, J. [Institut des Procedes Appliques aux Materiaux, Faculte des sciences de Limoges, 123 avenue Albert Thomas, 87060 Limoges cedex (France)
The plasma properties inside a D.C. arc-jet operating with argon is analysed by means of a continuum description taking into account non equilibrium ionization processes and dissipative effects. The relaxation of the different physical processes inside the nozzle and the evolution of the Mach number are aanalysed.
Laser induced fluorescence in a pulsed argon plasma
Earl Scime; Costel Biloiu; Christopher Compton; Forrest Doss; Daniel Venture; John Heard; Edgar Choueiri; Rostislav Spektor
A time-resolved laser induced fluorescence (LIF) technique for pulsed argon plasmas is described. A low power, tunable diode laser pumps a three level Ar II transition sequence at a wavelength of 668.6138 nm. With a standard LIF system designed for steady-state plasmas (e.g., 4 kHz optical chopper, 20 kHz band-width detector, and a lock-in amplifier), we demonstrate that the evolution
Temperature Profiles in Argon Induction Plasmas: Theory and Experiment
H. U. Eckert; D. C. Pridmore-Brown
A comparison is made between recent temperature measurements of argon induction plasmas which include cases of annular geometry and calculations based on the one-dimensional Elenbaas-Heller equation. Exact numerical solutions, as well as approximate closed-form solutions derived from a two-zone model are used. Good agreement is obtained for the central portion of the plasma column with the exact method for all
Resonance broadening of argon lines in a micro-scaled atmospheric pressure plasma jet (argon ?APPJ)
NASA Astrophysics Data System (ADS)
Pipa, A. V.; Ionikh, Yu. Z.; Chekishev, V. M.; Dünnbier, M.; Reuter, S.
Optical emission from atmospheric pressure micro-jet operating with pure argon (argon ?APPJ) flow has been detected with a moderate resolution spectrometer. Large broadening of the several argon (Ar) lines has been observed in the near infrared spectral region. This effect was attributed to resonance broadening of the s2 (Paschen notation) level in 3p54s configuration. In the present work, corresponding line profiles are suggested for plasma diagnostics. For this, a general case of resonance broadening coefficient of noble gases is discussed. As broadening reflects the Ar density, and the static gas pressure of the jet is in equilibrium with the ambient, the local gas temperature can be inferred. An estimation of gas temperature from the width of the 750 nm Ar line is in agreement with rotational temperature of OH radicals determined from the A2?+ ? X2? (0, 0) band. At low temperatures (300-600 K) and at partial Ar pressure near atmospheric, the resonance width of the suggested lines is very sensitive to small temperature variations. High temperature sensitivity and large width make the resonance broadened lines very attractive for diagnostics of low temperature discharges at elevated pressure, e.g., as they are used in plasma-medicine.
Flush-mounted probe diagnostics for argon glow discharge plasma
Xu, Liang, E-mail: firstname.lastname@example.com; Cao, Jinxiang; Liu, Yu; Wang, Jian; Du, Yinchang; Zheng, Zhe; Zhang, Xiao; Wang, Pi [Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhang, Jin; Li, Xiao; Qin, Yongqiang; Zhao, Liang [Science and Technology on Space Physics Laboratory, Beijing 100076 (China)
A comparison is made between plasma parameters measured by a flush-mounted probe (FP) and a cylindrical probe (CP) in argon glow discharge plasma. Parameters compared include the space potential, the plasma density, and the effective electron temperature. It is found that the ion density determined by the FP agrees well with the electron density determined by the CP in the quasi-neutral plasma to better than 10%. Moreover, the space potential and effective electron temperature calculated from electron energy distribution function measured by the FP is consistent with that measured by the CP over the operated discharge current and pressure ranges. These results present the FP can be used as a reliable diagnostic tool in the stable laboratory plasma and also be anticipated to be applied in other complicated plasmas, such as tokamaks, the region of boundary-layer, and so on.
XUV radiation from gaseous nitrogen and argon target laser plasmas
NASA Astrophysics Data System (ADS)
Vrba, P.; Vrbová, M.; Br?ža, P.; Pánek, D.; Krej?í, F.; Kroupa, M.; Jak?bek, J.
Laser plasma created in gaseous target is studied as a source of radiation in the "water window" wavelength range. Plasma is created by focusing an 800 mJ/7 ns Nd:YAG laser pulse into the gas-puff target. Using nitrogen gas results in emission of an intense quasi-monochromatic radiation with the wavelength 2.88 nm, corresponding to the quantum transition 1s2p ? 1s2 of helium -like nitrogen ion. The emission spectrum with argon target covers all the water window range. Laboratory and computer experiments have been performed for both target gases. The spatial distributions of emitted energy in the water window spectral range were compared. The total emitted energy with argon was one order higher than with nitrogen.
Langmuir Probe Measurements of an Expanding Argon Plasma
NASA Astrophysics Data System (ADS)
Cao, Xiaogang; Xia, Yuxi; Chen, Bingzhou; Tian, Shuping; Wang, Chunling; Yang, Dangxiao; Xue, Xiaoyan; Zhang, Weiwei; Wang, Jianqiang; Gou, Fujun; Zhu, Zichuan; Ou, Wei; Chen, Shunli
In this work, we studied the effects of the discharge current, gas flow rate and vessel pressure on the electron temperature and density of Ar plasma by Langmuir probe measurement. The argon plasma was created by a one-cathode arc source. The experimental results show that with increasing discharge current and gas flow rate, the electron temperature and density increase. It is found that when the discharge current is 70 A, 90 A and 110 A at an argon flow rate of 2000 sccm, the electron densities at about 0.186 m distance from the nozzle are 13.00×1018 m?3, 14.04×1018 m?3 and 15.62×1018 m?3, and the electron temperatures are 0.38 eV, 0.58 eV and 0.71 eV, respectively. The positive I-V characteristic is explained.
Numerical Modeling of an RF Argon-Silane Plasma with Dust Particle Nucleation and Growth
NASA Astrophysics Data System (ADS)
Girshick, Steven; Agarwal, Pulkit
We have developed a 1-D numerical model of an RF argon-silane plasma in which dust particles nucleate and grow. This model self-consistently couples a plasma module, a chemistry module and an aerosol module. The plasma module solves population balance equations for electrons and ions, the electron energy equation under the assumption of a Maxwellian velocity distribution, and Poisson's equation for the electric field. The chemistry module treats silane dissociation and reactions of silicon hydrides containing up to two silicon atoms. The aerosol module uses a sectional method to model particle size and charge distributions. The nucleation rate is equated to the rates of formation of anions containing two Si atoms, and a heterogeneous reaction model is used to model particle surface growth. Aerosol effects considered include particle charging, coagulation, and particle transport by neutral drag, ion drag, electric force, gravity and Brownian diffusion. Simulation results are shown for the case of a 13.56 MHz plasma at a pressure of 13 Pa and applied RF voltage of 100 V (amplitude), with flow through a showerhead electrode. These results show the strong coupling between the plasma and the spatiotemporal evolution of the nanoparticle cloud.
Comparison of local tumor recurrence following excision with the CO2 laser, Nd:YAG laser, and Argon Beam Coagulator.
Lanzafame, R J; Qiu, K; Rogers, D W; Naim, J O; Caldwell, F C; Perry, F; Hall, D; Hinshaw, J R
This study compares the incidence of local tumor recurrence following primary excision with the CO2 laser, Nd:YAG laser (contact), Argon Beam Coagulator, or electrocautery. One hundred eight Fisher 344 rats with R3230AC mammary tumors (1.6 +/- 0.04 [SD] cm diameter) were used. All animals were randomized into groups of similar tumor size. In groups C and CS, excision was performed with a Sharplan 1060 CO2 laser (TEMoo, 25 W, continuous wave [CW], 0.2-mm spot size). Wounds in group CS were "sterilized" (0.5-mm spot size, 25 W, CW) by gently heating the wound without causing blanching or charring. In group N, a 0.4-mm contact Laser Blade and a Cooper 8000 Nd:YAG laser at 20 W CW was used. In groups SA1 and SA2, tumors were excised with the scalpel, and hemostasis and wound "sterilization" were accomplished with the Bard System 6000 Argon Beam Coagulator (ABC) at 40 W and 4 liters/min argon gas flow in SA1 and 12 liters/min in SA2. In group E, excision was accomplished at 40 W blend mode, 10 W spray mode. In group EA, excision was accomplished at 60 W cutting current, and hemostasis was achieved with the ABC. The animals were examined for evidence of recurrence for 34 days postoperatively. Mortalities were excluded from analysis. The incidence of recurrence was 11/14 (79%) in C, 6/16 (38%) in CS, 10/14 (71%) in SA1, 6/13 (46%) in SA2, 6/15 (40%) in N, 7/10 (70%) in EA, and 3/15 (20%) in E. Group E is statistically different (P less than .01) from groups EA, C, and SA1. Group C was different (P less than .01) from groups E, CS, and N. These results demonstrate an inverse relationship between tumor recurrence and local thermal effects at the surgical site. The ABC did not increase tumor recurrence. Contact YAG surgery was similar to CO2 laser excision and "sterilization." An attempt to study the influence of gas flow and pressure on local tumor recurrence and metastases should be made. PMID:3230999
Nanopillar ITO electrodes via argon plasma etching
Van Dijken, Jaron G.; Brett, Michael J. [Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 2V4 (Canada); Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 2V4 (Canada) and NRC-National Institute for Nanotechnology, Edmonton, Alberta T6G 2M9 (Canada)
The authors demonstrate the formation of vertically aligned indium tin oxide (ITO) nanopillars by exposing planar ITO films to Ar plasma, the conditions of which determine the size, spacing, and aspect ratio of the pillars. Annealing in air and forming gas is used to recover and optimize the optical transmittance and electrical conductivity of the nanopillar films. The final product is an ITO film whose superior optical transmittance and strong electrical conductivity combine with its robust columnar morphology and processing scalability to make it suitable for use in highly absorbing organic solar cells.
Matthews, L. S.; Land, V.; Hyde, T. W., E-mail: firstname.lastname@example.com [Center for Astrophysics, Space Physics, and Engineering Research, Baylor University, Waco, TX 76798-7316 (United States)
Combining a particle-particle, particle-cluster, and cluster-cluster agglomeration model with an aggregate charging model, the coagulation and charging of dust particles in plasma environments relevant for protoplanetary disks have been investigated, including the effect of electron depletion in high dust density environments. The results show that charged aggregates tend to grow by adding small particles and clusters to larger particles and clusters, and that cluster-cluster aggregation is significantly more effective than particle-cluster aggregation. Comparisons of the grain structure show that with increasing aggregate charge the compactness factor, {phi}{sub {sigma}}, decreases and has a narrower distribution, indicating a fluffier structure. Neutral aggregates are more compact, with larger {phi}{sub {sigma}}, and exhibit a larger variation in fluffiness. Overall, increased aggregate charge leads to larger, fluffier, and more massive aggregates.
Plasma core reactor simulations using RF uranium seeded argon discharges
NASA Technical Reports Server (NTRS)
Roman, W. C.
An experimental investigation was conducted using the United Technologies Research Center (UTRC) 80 kW and 1.2 MW RF induction heater systems to aid in developing the technology necessary for designing a self-critical fissioning uranium plasma core reactor (PCR). A nonfissioning, steady-state RF-heated argon plasma seeded with pure uranium hexafluoride (UF6) was used. An overall objective was to achieve maximum confinement of uranium vapor within the plasma while simultaneously minimizing the uranium compound wall deposition. Exploratory tests were conducted using the 80 kW RF induction heater with the test chamber at approximately atmospheric pressure and discharge power levels on the order of 10 kW. Four different test chamber flow configurations were tested to permit selection of the configuration offering the best confinement characteristics for subsequent tests at higher pressure and power in the 1.2 MW RF induction heater facility.
Plasma core reactor simulations using RF uranium seeded argon discharges
NASA Technical Reports Server (NTRS)
Roman, W. C.
Experimental results are described in which pure uranium hexafluoride was injected into an argon-confined, steady-state, RF-heated plasma to investigate characteristics of plasma core nuclear reactors. The 80 kW (13.56 MHz) and 1.2 MW (5.51 MHz) rf induction heater facilities were used to determine a test chamber flow scheme which offered best uranium confinement with minimum wall coating. The cylindrical fused-silica test chamber walls were 5.7-cm-ID by 10-cm-long. Test conditions included RF powers of 2-85 kW, chamber pressures of 1-12 atm, and uranium hexafluoride mass-flow rates of 0.005-0.13 g/s. Successful techniques were developed for fluid-mechanical confinement of RF-heated plasmas with pure uranium hexafluoride injection.
Changes in Dietary Fat Content Rapidly Alters the Mouse Plasma Coagulation Profile without Affecting Relative Transcript Levels of Coagulation Factors
van Diepen, Janna A.; Verhoef, Daniël; Voshol, Peter J.; Reitsma, Pieter H.; van Vlijmen, Bart J. M.
Background Obesity is associated with a hypercoagulable state and increased risk for thrombotic cardiovascular events. Objective Establish the onset and reversibility of the hypercoagulable state during the development and regression of nutritionally-induced obesity in mice, and its relation to transcriptional changes and clearance rates of coagulation factors as well as its relation to changes in metabolic and inflammatory parameters. Methods Male C57BL/6J mice were fed a low fat (10% kcal as fat; LFD) or high fat diet (45% kcal as fat; HFD) for 2, 4, 8 or 16 weeks. To study the effects of weight loss, mice were fed the HFD for 16 weeks and switched to the LFD for 1, 2 or 4 weeks. For each time point analyses of plasma and hepatic mRNA levels of coagulation factors were performed after overnight fasting, as well as measurements of circulating metabolic and inflammatory parameters. Furthermore, in vivo clearance rates of human factor (F) VII, FVIII and FIX proteins were determined after 2 weeks of HFD-feeding. Results HFD feeding gradually increased the body and liver weight, which was accompanied by a significant increase in plasma glucose levels from 8 weeks onwards, while insulin levels were affected after 16 weeks. Besides a transient rise in cytokine levels at 2 weeks after starting the HFD, no significant effect on inflammation markers was present. Increased plasma levels of fibrinogen, FII, FVII, FVIII, FIX, FXI and FXII were observed in mice on a HFD for 2 weeks, which in general persisted throughout the 16 weeks of HFD-feeding. Interestingly, with the exception of FXI the effects on plasma coagulation levels were not paralleled by changes in relative transcript levels in the liver, nor by decreased clearance rates. Switching from HFD to LFD reversed the HFD-induced procoagulant shift in plasma, again not coinciding with transcriptional modulation. Conclusions Changes in dietary fat content rapidly alter the mouse plasma coagulation profile, thereby preceding plasma metabolic changes, which cannot be explained by changes in relative expression of coagulation factors or decreased clearance rates. PMID:26176620
Generation of argon-ion mixed silicon plasmas forming argon encapsulated silicon clusters
Kaneko, T.; Takaya, H.; Hatakeyama, R. [Department of Electronic Engineering, Tohoku University, Sendai 980-8579 (Japan)
An inductively coupled argon (Ar) plasma is superimposed on a silicon (Si) plasma generated by an electron beam gun in order to realize the formation of gas-atom encapsulated Si cage clusters. The Si clusters, which are formed and deposited on a substrate, are analyzed by laser-desorption time-of-flight mass spectrometry and are found to have the mass spectra of not only pure Si cluster (Si{sub n}; n=1-17) but also Si cluster doped with Ar atom (ArSi{sub n}; n=10-20) in the case that the large amount of Ar ions is generated in addition to the Si plasma. Together with the analysis of x-ray photoelectron spectroscopy, it is revealed that the Ar atom is included in the Si cluster, forming the structure of endohedral Ar at Si{sub n} complexes. Furthermore, the mass spectrum of Ar at Si{sub n} indicates the existence of the magic numbered cluster size n=15, 16 similar to the metal encapsulated Si clusters.
Effect of the levitating microparticle cloud on radiofrequency argon plasma
Mitic, S.; Pustylnik, M. Y.; Klumov, B. A.; Morfill, G. E. [Max-Planck-Institut fuer Extraterrestrische Physik, Giessenbachstrasse 1, 85741, Garching (Germany)
The effect of a levitating cloud of microparticles on the parameters of a radiofrequency (RF) plasma has been studied by means of two experimental techniques. Axial distributions of 1s excited states of argon were measured by a self-absorption method. A correction of a standard self-absorption method for the extinction of the light by the levitating microparticles is proposed. In addition the electron temperature was estimated using the optical emission spectroscopy. Measurements at the same discharge conditions in a microparticle-free discharge and discharge, containing a cloud of levitating microparticles, revealed the non-local influence of the microparticle cloud on the discharge plasma. The most probable cause of this influence is the disturbance of the ionization balance by the levitating microparticles.
Characterization of SF6/Argon Plasmas for Microelectronics Applications
This report documents measurements in inductively driven plasmas containing SF{sub 6}/Argon gas mixtures. The data in this report is presented in a series of appendices with a minimum of interpretation. During the course of this work we investigated: the electron and negative ion density using microwave interferometry and laser photodetachment; the optical emission; plasma species using mass spectrometry, and the ion energy distributions at the surface of the rf biased electrode in several configurations. The goal of this work was to assemble a consistent set of data to understand the important chemical mechanisms in SF{sub 6} based processing of materials and to validate models of the gas and surface processes.
Atmospheric Pressure Humid Argon DBD Plasma for the Application of Sterilization -Measurement and Simulation of Hydrogen, Oxygen, and Hydrogen
Paris-Sud XI, Université de
,3-7]; investigation of argon plasma 'cleaning' of surfaces has also been made [8-9]. In additionAtmospheric Pressure Humid Argon DBD Plasma for the Application of Sterilization - Measurement. The results of experiments on the use of post-discharge effluent gas of humid argon plasma for sterilization
Nonthermal atmospheric argon plasma jet effects on Escherichia coli biomacromolecules.
Hosseinzadeh Colagar, Abasalt; Memariani, Hamed; Sohbatzadeh, Farshad; Valinataj Omran, Azadeh
Nonthermal atmospheric plasma jet, a promising technology based on ionized gas at low temperatures, can be applied for disinfection of contaminated surfaces. In this study, Escherichia coli cells and their macromolecules were exposed to the nonthermal atmospheric argon plasma jet for different time durations. Total protein, genomic DNA, and malondialdehyde (MDA) levels of E. coli were assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining; agarose gel electrophoresis; and measurement of absorbance at 534 nm, respectively. After exposure, the spectroscopic results of liquid samples indicated that the survival reduction of E. coli can reach to 100 % in an exposure time of 600 s. Moreover, inactivation zones of E. coli, DNA degradation, and MDA levels were significantly increased. Additionally, banding patterns of total protein were changed and amino acid concentrations increased following ninhydrin test. The experimental results suggest that the nonthermal plasma could serve as an effective instrument for both sterilizing E. coli and degrading macromolecules from the surface of the objects being sterilized. PMID:23982422
Activated plasma coagulation ?-Factor XII-induced vasoconstriction in rats
Papageorgiou, Peter C.; Yeo, Erik L.; Backx, Peter H.; Floras, John S.
By inducing BK (bradykinin)-stimulated adrenomedullary catecholamine release, bolus injection of the ?-fragment of activated plasma coagulation Factor XII (?-FXIIa) transiently elevates BP (blood pressure) and HR (heart rate) of anaesthetized, vagotomized, ganglion-blocked, captopril-treated bioassay rats. We hypothesized that intravenous infusion of ?-FXIIa into intact untreated rats would elicit a qualitatively similar vasoconstrictor response. BN (Brown Norway) rats received for 60 min either: (i) saline (control; n=10); (ii) ?-FXIIa (85 ng/min per kg of body weight; n=9); or (iii) ?-FXIIa after 2ADX (bilateral adrenalectomy; n=9). LV (left ventricular) volume and aortic BP were recorded before (30 min baseline), during (60 min) and after (30 min recovery) the infusion. TPR (total peripheral resistance) was derived from MAP (mean arterial pressure), SV (stroke volume) and HR. Saline had no haemodynamic effects. ?-FXIIa infusion increased its plasma concentration 3-fold in both groups. In adrenally intact rats, ?-FXIIa infusion increased MAP by 6% (5±2 mmHg) and TPR by 45% (0.50±0.12 mmHg/ml per min), despite falls in SV (?38±8 ?l) and HR [?18±5 b.p.m. (beats/min)] (all P<0.05). In 2ADX rats, ?-FXIIa had no HR effect, but decreased SV (?89±9 ?l) and MAP (?4±1 mmHg), and increased TPR by 66% (0.59±0.15 mmHg/ml per min) (all P<0.05). After infusion, adrenally intact rats exhibited persistent vasoconstriction (MAP, 10±1 mmHg; TPR, 0.55±0.07 mmHg/ml per min; both P<0.05), whereas in 2ADX rats, MAP remained 5±1 mmHg below baseline (P<0.05) and TPR returned to baseline. End-study arterial adrenaline (epinephrine) concentrations in the three groups were 1.9±0.6, 9.8±4.1 and 0.6±0.2 nmol/l respectively. Thus, in neurally intact lightly anaesthetized untreated rats, ?-FXIIa infusion induces both adrenal catecholamine-mediated and adrenally independent increases in peripheral resistance. PMID:22216926
Development of a microplate coagulation assay for Factor V in human plasma
Derek Tilley; Irina Levit; John A Samis
Background Factor V (FV) in its activated form, FVa, is a critical regulator of thrombin generation during fibrin clot formation. There\\u000a is a need of a simple, fast, and inexpensive microplate-based coagulation assay to measure the functional activity of FV in\\u000a human plasma. The objective of this study was to develop a microplate-based assay that measures FV coagulation activity during\\u000a clot
Elastic and Transport Cross Sections for Argon and Carbon in Hydrogen Plasmas
NASA Astrophysics Data System (ADS)
Schultz, David; Krstic?, Predrag
The elastic transport processes of argon and carbon in the hydrogen plasma is of fundamental importance in a variety of plasma environments. Thus, hydrogen argon-mixtures are utilized in plasma processing and in low pressure discharges. Argon is also useful as an impurity ion tracer in a magnetic fusion plasmas. On the other hand, interest in the carbon transport stems from the ubiquity of graphite used as a plasma facing material in many present and planned fusion devices. By utilizing the fully quantum approach, we have calculated accurate elastic differential and integral scattering cross sections as well as the transport coefficients for hydrogen (deuterium, tritium) ions colliding with argon and carbon in the center of mass energy 0.1-100 eV. Momentum transfer and viscosity were extended to higher collision energies (up to 10 keV) using classical methods. Results were compared with previously recommended values.
Common versus noble Bacillus subtilis differentially responds to air and argon gas plasma.
Winter, Theresa; Bernhardt, Jörg; Winter, Jörn; Mäder, Ulrike; Schlüter, Rabea; Weltmann, Klaus-Dieter; Hecker, Michael; Kusch, Harald
The applications of low-temperature plasma are not only confined to decontamination and sterilization but are also found in the medical field in terms of wound and skin treatment. For the improvement of already established and also for new plasma techniques, in-depth knowledge on the interactions between plasma and microorganism is essential. In an initial study, the interaction between growing Bacillus subtilis and argon plasma was investigated by using a growth chamber system suitable for low-temperature gas plasma treatment of bacteria in liquid medium. In this follow-up investigation, a second kind of plasma treatment-namely air plasma-was applied. With combined proteomic and transcriptomic analyses, we were able to investigate the plasma-specific stress response of B. subtilis toward not only argon but also air plasma. Besides an overlap of cellular responses due to both argon and air plasma treatment (DNA damage and oxidative stress), a variety of gas-dependent cellular responses such as growth retardation and morphological changes were observed. Only argon plasma treatments lead to a phosphate starvation response whereas air plasma induced the tryptophan operon implying damage by photooxidation. Biological findings were supported by the detection of reactive plasma species by optical emission spectroscopy and Fourier transformed infrared spectroscopy measurements. PMID:23794223
Properties of a capillary discharge-produced argon plasma waveguide for shorter wavelength source application
NASA Astrophysics Data System (ADS)
Sakai, Shohei; Higashiguchi, Takeshi; Bobrova, Nadezhda; Sasorov, Pavel; Miyazawa, Jun; Yugami, Noboru; Sentoku, Yasuhiko; Kodama, Ryosuke
We report the operation of a discharge-produced argon (Ar) plasma waveguide in an alumina (Al2O3) capillary to guide a 1016-W/cm2 ultrashort laser pulse for shorter wavelength light sources at high repetition rate operation. The electron density in the plasma channel was measured to be 1 × 1018 cm-3. Modeling with a one-dimensional magnetrohydrodynamic code was used to evaluate the degree of ionization of Ar in the preformed plasma channel. The observed spectrum of the laser pulse after propagation in the argon plasma waveguide was not modified and was well reproduced by a particle in cell simulation.
Properties of a capillary discharge-produced argon plasma waveguide for shorter wavelength source application.
Sakai, Shohei; Higashiguchi, Takeshi; Bobrova, Nadezhda; Sasorov, Pavel; Miyazawa, Jun; Yugami, Noboru; Sentoku, Yasuhiko; Kodama, Ryosuke
We report the operation of a discharge-produced argon (Ar) plasma waveguide in an alumina (Al(2)O(3)) capillary to guide a 10(16)-W/cm(2) ultrashort laser pulse for shorter wavelength light sources at high repetition rate operation. The electron density in the plasma channel was measured to be 1 × 10(18) cm(-3). Modeling with a one-dimensional magnetrohydrodynamic code was used to evaluate the degree of ionization of Ar in the preformed plasma channel. The observed spectrum of the laser pulse after propagation in the argon plasma waveguide was not modified and was well reproduced by a particle in cell simulation. PMID:22047296
A piezoelectric quartz crystal sensor for the determination of coagulation time in plasma and whole blood
Tzong-Jih Cheng; Hsein-Chang Chang; Tsun-Mei Lin
A Piezoelectric Quartz Crystal (PQC) system possessing an adequate sensitivity to a slight viscosity change is employed to monitor the blood coagulation. In the case of an anticoagulated plasma specimen, prothrombin time (PT) was determined by the PQC sensor on the basis of the introduction of tissue thromboplastin (TF) and calcium ion. Discussing the PQC data statistically, we found that
Methylmethacrylate bone cement surface does not promote platelet aggregation or plasma coagulation in vitro
Aleš Blinc; Mojca Boži?; Rok Vengust; Mojca Stegnar
Leakage of viscous bone cement into venous blood possibly resulting in pulmonary embolism may occur during percutaneous vertebroplasty. Our aim was to study if bone cement surface or cement liquid component could induce platelet aggregation or plasma coagulation in vitro. Two types of commonly used methyl-methacrylate bone cement, Palacos R (Heraeus Kulzer, Germany) and Vertebroplastic TM (DePuy, Acro Med, England),
Multidimensional Simulation of Plasma in Argon through a Shock in Hypersonic Flow
Alonso, Juan J.
Multidimensional Simulation of Plasma in Argon through a Shock in Hypersonic Flow Amrita K. Lonkar in gases at hypersonic speeds. A plasma is composed of multiple species in thermo-chemical nonequlibrium of hypersonics in the past quarter century. Rocket- powered launch vehicles typically achieve hypersonic speeds
Polydiagnostic calibration performed on a low pressure surface wave sustained argon plasma
N. de Vries; J. M. Palomares; E. I. Iordanova; E. M. van Veldhuizen; J. J. A. M. van der Mullen
The electron density and electron temperature of a low pressure surface wave sustained argon plasma have been determined using passive and active (laser) spectroscopic methods simultaneously. In this way the validity of the various techniques is established while the plasma properties are determined more precisely. The electron density, ne, is determined with Thomson scattering (TS), absolute continuum measurements, Stark broadening
The response of the inductively coupled argon plasma to solvent plasma load: spatially resolved maps of electron density obtained from the intensity of one argon line
NASA Astrophysics Data System (ADS)
Weir, D. G. J.; Blades, M. W.
A survey of spatially resolved electron number density ( ne) in the tail cone of the inductively coupled argon plasma (ICAP) is presented: all of the results of the survey have been radially inverted by numerical, asymmetric Abel inversion. The survey extends over the entire volume of the plasma beyond the exit of the ICAP torch; It extends over distances of z = 5-25 mm downstream from the induction coil, and over radial distances of ± 8 mm from the discharge axis. The survey also explores a range of inner argon flow rates ( QIN), solvent plasma load ( Qspl) and r.f. power: moreover, it explores loading by water, methanol and chloroform. Throughout the survey, ne was determined from the intensity of one, optically thin argon line, by a method which assumes that the atomic state distribution function (ASDF) for argon lies close to local thermal equilibrium (LTE). The validity of this assumption is reviewed. Also examined are the discrepancies between ne from this method and ne from Stark broadening measurements. With the error taken into account, the results of the survey reveal how time averaged values of ne in the ICAP respond over an extensive, previously unexplored range of experimental parameters. Moreover, the spatial information lends insight into how the thermal conditions and the transport of energy respond. Overall, the response may be described in terms of energy consumption along the axial channel and thermal pinch within the induction region. The predominating effect depends on the solvent plasma load, the solvent composition, the robustness of the discharge, and the distribution of solvent material over the argon stream.
Atmospheric Pressure Cold Argon/Oxygen Plasma Jet Assisted by Preionization of Syringe Needle Electrode
NASA Astrophysics Data System (ADS)
Qian, Muyang; Ren, Chunsheng; Wang, Dezhen; Feng, Yan; Zhang, Jialiang
An atmospheric pressure nonequilibrium argon/oxygen plasma jet assisted by the preionization of syringe needle electrode discharge is reported. With the syringe needle plasma as its pre-ionization source, the hybrid barrier-jet was shown to generate uniform discharge with a lower breakdown voltage and a relatively low gas temperature varying from 390 K to 440 K, even when the vol.% oxygen in argon was up to 6%. Utilizing the actinometry method, the concentration of atomic oxygen was estimated to be about in an orders of magnitude of 1017 cm-3. The argon/oxygen plasma jet was then employed to clean out heat transfer oil, with a maximum cleaning rate of 0.1 mm/s achieved.
Introduction of argon beam coagulation functionality to robotic procedures using the ABC D-Flex probe: equivalency to an existing laparoscopic instrument
NASA Astrophysics Data System (ADS)
Merchel, Renée. A.; Barnes, Kelli S.; Taylor, Kenneth D.
INTRODUCTION: The ABC® D-Flex Probe utilizes argon beam coagulation (ABC) technology to achieve hemostasis during minimally invasive surgery. A handle on the probe allows for integration with robotic surgical systems and introduces ABC to the robotic toolbox. To better understand the utility of D-Flex, this study compares the performance of the D-Flex probe to an existing ABC laparoscopic probe through ex vivo tissue analysis. METHODS: Comparisons were performed to determine the effect of four parameters: ABC device, tissue type, activation duration, and distance from tissue. Ten ABC D-Flex probes were used to create 30 burn samples for each comparison. Ex vivo bovine liver and porcine muscle were used as tissue models. The area and depth of each burn was measured using a light microscope. The resulting dimensional data was used to correlate tissue effect with each variable. RESULTS: D-Flex created burns which were smaller in surface area than the laparoscopic probe at all power levels. Additionally, D-Flex achieved thermal penetration levels equivalent to the laparoscopic probe. CONCLUSION: D-Flex implements a small 7F geometry which creates a more focused beam. When used with robotic precision, quick localized superficial hemostasis can be achieved with minimal collateral damage. Additionally, D-Flex achieved equivalent thermal penetration levels at lower power and argon flow-rate settings than the laparoscopic probe.
Comparison of functional aspects of the coagulation cascade in human and sea turtle plasmas.
Soslau, Gerald; Wallace, Bryan; Vicente, Catherine; Goldenberg, Seth J; Tupis, Todd; Spotila, James; George, Robert; Paladino, Frank; Whitaker, Brent; Violetta, Gary; Piedra, Rotney
Functional hemostatic pathways are critical for the survival of all vertebrates and have been evolving for more than 400 million years. The overwhelming majority of studies of hemostasis in vertebrates have focused on mammals with very sparse attention paid to reptiles. There have been virtually no studies of the coagulation pathway in sea turtles whose ancestors date back to the Jurassic period. Sea turtles are often exposed to rapidly altered environmental conditions during diving periods. This may reduce their blood pH during prolonged hypoxic dives. This report demonstrates that five species of turtles possess only one branch of the mammalian coagulation pathway, the extrinsic pathway. Mixing studies of turtle plasmas with human factor-deficient plasmas indicate that the intrinsic pathway factors VIII and IX are present in turtle plasma. These two factors may play a significant role in supporting the extrinsic pathway by feedback loops. The intrinsic factors, XI and XII are not detected which would account for the inability of reagents to induce coagulation via the intrinsic pathway in vitro. The analysis of two turtle factors, factor II (prothrombin) and factor X, demonstrates that they are antigenically/functionally similar to the corresponding human factors. The turtle coagulation pathway responds differentially to both pH and temperature relative to each turtle species and relative to human samples. The coagulation time (prothrombin time) increases as the temperature decreases between 37 and 15 degrees C. The increased time follows a linear relationship, with similar slopes for loggerhead, Kemps ridley and hawksbill turtles as well as for human samples. Leatherback turtle samples show a dramatic nonlinear increased time below 23 degrees C, and green turtle sample responses were similar but less dramatic. All samples also showed increased prothrombin times as the pH decreased from 7.8 to 6.4, except for three turtle species. The prothrombin times decreased, to varying extents, in a linear fashion relative to reduced pH with the rate of change greatest in leatherbacks>green>loggerhead turtles. All studies were conducted with reagents developed for human samples which would impact on the quantitative results with the turtle samples, but are not likely to alter the qualitative results. These comparative studies of the coagulation pathway in sea turtles and humans could enhance our knowledge of structure/function relationships and evolution of coagulation factors. PMID:15325341
Measurement of plasma decay processes in mixture of sodium and argon by coherent microwave scattering
Zhang Zhili [Mechanical, Aerospace and Biomedical Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States); Shneider, Mikhail N. [Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States)
This paper presents the experimental measurement and computational model of sodium plasma decay processes in mixture of sodium and argon by using radar resonance-enhanced multiphoton ionization (REMPI), coherent microwave Rayleigh scattering of REMPI. A single laser beam resonantly ionizes the sodium atoms by means of 2+1 REMPI process. The laser beam can only generate the ionization of the sodium atoms and have negligible ionization of argon. Coherent microwave scattering in situ measures the total electron number in the laser-induced plasma. Since the sodium ions decay by recombination with electrons, microwave scattering directly measures the plasma decay processes of the sodium ions. A theoretical plasma dynamic model, including REMPI of the sodium and electron avalanche ionization (EAI) of sodium and argon in the gas mixture, has been developed. It confirms that the EAI of argon is several orders of magnitude lower than the REMPI of sodium. The theoretical prediction made for the plasma decay process of sodium plasma in the mixture matches the experimental measurement.
Surface-mediated molecular events in material-induced blood-plasma coagulation
NASA Astrophysics Data System (ADS)
Chatterjee, Kaushik
Coagulation and thrombosis persist as major impediments associated with the use of blood-contacting medical devices. We are investigating the molecular mechanism underlying material-induced blood-plasma coagulation focusing on the role of the surface as a step towards prospective development of improved hemocompatible biomaterials. A classic observation in hematology is that blood/blood-plasma in contact with clean glass surface clots faster than when in contact with many plastic surfaces. The traditional biochemical theory explaining the underlying molecular mechanism suggests that hydrophilic surfaces, like that of glass, are specific activators of the coagulation cascade because of the negatively-charged groups on the surface. Hydrophobic surfaces are poor procoagulants or essentially "benign" because they lack anionic groups. Further, these negatively-charged surfaces are believed to not only activate blood factor XII (FXII), the key protein in contact activation, but also play a cofactor role in the amplification and propagation reactions that ultimately lead to clot formation. In sharp contrast to the traditional theory, our investigations indicate a need for a paradigm shift in the proposed sequence of contact activation events to incorporate the role of protein adsorption at the material surfaces. These studies have lead to the central hypothesis for this work proposing that protein adsorption to hydrophobic surfaces attenuates the contact activation reactions so that poorly-adsorbent hydrophilic surfaces appear to be stronger procoagulants relative to hydrophobic surfaces. Our preliminary studies measuring the plasma coagulation response of activated FXII (FXIIa) on different model surfaces suggested that the material did not play a cofactor role in the processing of this enzyme dose through the coagulation pathway. Therefore, we focused our efforts on studying the mechanism of initial production of enzyme at the procoagulant surface. Calculations for the amounts of FXIIa generated at material surfaces in plasma using a mathematical model for measured coagulation responses indicate that the relative contributions of the individual pathways of enzyme generation are similar at both hydrophilic and hydrophobic surfaces, only the amounts of enzyme generated scale with surface energy and area of the activating surface. Further, from direct measurement of enzyme activation at test surfaces we observed that contact activation reactions are not specific to negatively-charged hydrophilic surfaces. Rather, the molecular interactions are attenuated at hydrophobic surfaces due to protein adsorption so that poorly-adsorbent hydrophilic surfaces exhibit an apparent specificity for contact activation reactions. Preliminary studies were preformed to assay the plasma coagulation response to low-fouling surfaces prepared by either grafting poly(ethylene glycol) chains or using zwitterions. Results indicate that poly(ethylene glycol)-modified surfaces are significantly weaker procoagulants than surfaces containing zwitterions underscoring a need to specifically evaluate the coagulation response despite similarities in observed protein adsorption to both surfaces. In summary, our studies demonstrate a need to incorporate protein-adsorption competition at procoagulant surfaces into the mechanism of contact activation to account for the observed moderation of FXII activation by blood proteins unrelated to the plasma coagulation cascade.
Nucleation of silicon nanocrystals in a remote plasma without subsequent coagulation
NASA Astrophysics Data System (ADS)
Do?an, Ilker; Weeks, Stephen L.; Agarwal, Sumit; van de Sanden, Mauritius C. M.
We report on the growth mechanism of spherical silicon nanocrystals in a remote expanding Ar plasma using a time-modulated SiH4 gas injection in the microsecond time range. Under identical time-modulation parameters, we varied the local density of the SiH4 gas by changing its stagnation pressure on the injection line over the range of 0.1-2.0 bar. We observed that nanocrystals were synthesized in a size range from ˜2 to ˜50 nm with monocrystalline morphology. Smaller nanocrystals (˜2-6 nm) with narrower size distributions and with higher number densities were synthesized with an increase of the SiH4 gas-phase density. We related this observation to the rapid depletion of the number density of the molecules, ions, and radicals in the plasma during nanocrystal growth, which can primarily occur via nucleation with no significant subsequent coagulation. In addition, in our remote plasma environment, rapid cooling of the gas in the particle growth zone from ˜1500 to ˜400 K significantly reduces the coalescence rate of the nanoparticles, which makes the coagulation process highly unlikely. Our observations on nanocrystal formation via nucleation indicated that subsequent coagulation for further growth is not always an essential step on nanoparticle formation.
Test of an argon cusp plasma for tin LPP power scaling
NASA Astrophysics Data System (ADS)
McGeoch, Malcolm W.
Scaling the power of the tin droplet laser-produced-plasma (LPP) extreme ultraviolet (EUV) source to 500W has eluded the industry after a decade of effort. In 2014 we proposed [2] a solution: placing the laser-plasma interaction region within an argon plasma in a magnetic cusp. This would serve to ionize tin atoms and guide them to a large area annular beam dump. We have since demonstrated the feasibility of this approach. We present first results from a full-scale test plasma at power levels relevant to the generation of at least 200W, showing both that the argon cusp plasma is very stable, and that its geometrical properties are ideal for the transport of exhaust power and tin to the beam dump.
Characteristics of argon plasma waveguide produced by alumina capillary discharge for short wavelength laser application
NASA Astrophysics Data System (ADS)
Higashiguchi, Takeshi; Bobrova, Nadezhda; Sasorov, Pavel; Sakai, Shohei; Sentoku, Yasuhiko; Kodama, Ryosuke; Yugami, Noboru
We have reported the argon (Ar) plasma waveguide produced in an alumina (Al2O3) capillary discharge and used to guide ultrashort laser pulses at intensities of the order of 1016 W/cm2. The electron density in the plasma waveguide was measured to be 1×1018 cm-3, in agreement with one-dimensional magnetrohydrodynamic (MHD) simulations. The MHD code was also used to evaluate the degree of ionization of argon (Ar) in the preformed plasma waveguide. The maximum ion charge state of Ar3+ in capillary discharge was measured and obtained in the MHD simulations. The spectrum of the propagated laser pulse in the Ar plasma waveguide was not modified and was well reproduced by a particle-in-cell simulations under initial ion charge state of Ar3+ in the preformed plasma waveguide. The optimum timing for the laser pulse injection was around 150 ns after initiation of a discharge with a peak current of 200 A.
Inactivation of human immunodeficiency virus by gamma radiation and its effect on plasma and coagulation factors
Hiemstra, H.; Tersmette, M.; Vos, A.H.; Over, J.; van Berkel, M.P.; de Bree, H. (Central Laboratory of The Netherlands, Red Cross Blood Transfusion Service, Amsterdam (Netherlands))
The inactivation of HIV by gamma-radiation was studied in frozen and liquid plasma; a reduction of the virus titer of 5 to 6 logs was achieved at doses of 5 to 10 Mrad at -80 degrees C and 2.5 Mrad at 15 degrees C. The effect of irradiation on the biologic activity of a number of coagulation factors in plasma and in lyophilized concentrates of factor VIII (FVIII) and prothrombin complex was examined. A recovery of 85 percent of the biologic activity of therapeutic components present in frozen plasma and in lyophilized coagulation factor concentrates was reached at radiation doses as low as 1.5 and 0.5 Mrad, respectively. As derived from the first-order radiation inactivation curves, the radiosensitive target size of HIV was estimated to be 1 to 3 MDa; the target size of FVIII was estimated to be 130 to 160 kDa. Gamma radiation must be disregarded as a method for the sterilization of plasma and plasma-derived products, because of the low reduction of virus infectivity at radiation doses that still give acceptable recovery of biologic activity of plasma components.
Impacts of leukocyte filtration and irradiation on coagulation factors in fresh frozen plasma
This study aimed to compare and analyze the changes in the coagulation factors in fresh frozen plasma (FFP) prior to and following leukocyte filtration and irradiation. In total, 30 bags of FFP from healthy donors were processed: One-third of the FFP of each bag was left within the original bag (the A group), the other two-thirds of the FFP of each bag were passed through a disposable leukocyte filter, then divided equally into two parts. One of these was designated as the B group, and the other was designated the C group (subjected to 30 Gy irradiation). All samples were analyzed to evaluate 16 coagulation indicators. Analysis of variance revealed that there were statistically significant differences in the levels of fibrinogen (FbgC) and coagulation factor VIII (FVIII:C) among the groups (P=0.044 and P=0.015, respectively); the Dunnett's t-test revealed that there was a statistically significant difference in the level of FbgC between the A and B groups (P=0.025), and there was a statistically significant difference in the level of FVIII:C between the A and C groups (P=0.009); while the remaining 14 coagulation parameters were not significantly different among the groups. Although the levels of FbgC and FVIII:C in the FFP were reduced following treatment, this would not affect the clinical effect of the FFP. PMID:25574241
Ionic Wind Phenomenon and Charge Carrier Mobility in Very High Density Argon Corona Discharge Plasma
NASA Astrophysics Data System (ADS)
Nur, M.; Bonifaci, N.; Denat, A.
Wind ions phenomenon has been observed in the high density argon corona discharge plasma. Corona discharge plasma was produced by point to plane electrodes and high voltage DC. Light emission from the recombination process was observed visually. The light emission proper follow the electric field lines that occur between point and plane electrodes. By using saturation current, the mobilities of non-thermal electrons and ions have been obtained in argon gas and liquid with variation of density from 2,5 1021 to 2 1022 cm-3. In the case of ions, we found that the behaviour of the apparent mobility inversely proportional to the density or follow the Langevin variation law. For non-thermal electron, mobility decreases and approximately follows a variation of Langevin type until the density <= 0,25 the critical density of argon.
Properties of a capillary discharge-produced argon plasma waveguide for shorter wavelength source application
Sakai, Shohei; Miyazawa, Jun [Department of Advanced Interdisciplinary Sciences, Center for Optical Research and Education (CORE), and Optical Technology Innovation Center (OpTIC), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Higashiguchi, Takeshi; Yugami, Noboru [Department of Advanced Interdisciplinary Sciences, Center for Optical Research and Education (CORE), and Optical Technology Innovation Center (OpTIC), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Japan Science and Technology Agency, CREST, 4-1-8 Honcho, Kanagawa, Saitama 332-0012 (Japan); Bobrova, Nadezhda; Sasorov, Pavel [Institute for Theoretical and Experimental Physics, B. Cheremushkinskaya str. 25, 117218 Moscow (Russian Federation); Sentoku, Yasuhiko [Department of Physics, University of Nevada, Mail Stop 220, Reno, Nevada 89506 (United States); Kodama, Ryosuke [Japan Science and Technology Agency, CREST, 4-1-8 Honcho, Kanagawa, Saitama 332-0012 (Japan); Graduate School of Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan)
We report the operation of a discharge-produced argon (Ar) plasma waveguide in an alumina (Al{sub 2}O{sub 3}) capillary to guide a 10{sup 16}-W/cm{sup 2} ultrashort laser pulse for shorter wavelength light sources at high repetition rate operation. The electron density in the plasma channel was measured to be 1 x 10{sup 18} cm{sup -3}. Modeling with a one-dimensional magnetrohydrodynamic code was used to evaluate the degree of ionization of Ar in the preformed plasma channel. The observed spectrum of the laser pulse after propagation in the argon plasma waveguide was not modified and was well reproduced by a particle in cell simulation.
Chemical and physical changes in surface of Argon plasma treated cotton fabrics
S. Inbakumar; A. Anukaliani
Hydrophilic cotton fabrics were exposed by low-pressure DC glow discharge plasma in argon atmosphere. The influence of different operating parameters such as treatment time, discharge potential, and operating pressure on the chemical and physical properties of the cotton fabrics is studied. Surface analysis and characterization of the plasma-treated cotton fabrics is performed using vertical wicking experiments, X-ray photoelectron spectroscopy, scanning
Modelling of an inductively coupled plasma torch with argon at atmospheric pressure
NASA Astrophysics Data System (ADS)
Bahouh, Hanene; Rebiai, Saida; Rochette, David; Vacher, Damien; Dudeck, Michel
A fluid dynamic model is used to simulate the electromagnetic field, fluid flow and heat transfer in an inductively coupled plasma torch working at atmospheric pressure for argon plasma. The numerical simulation is carried out by using the finite element method based on COMSOL software. The two-dimensional profiles of the electric field, temperature, velocity and charged particle densities are demonstrated inside the discharge region. These numerical results are obtained for a fixed flow rate, frequency and electric power.
Spatio-temporal dynamics of a pulsed microwave argon plasma: ignition and afterglow
NASA Astrophysics Data System (ADS)
Carbone, Emile; Sadeghi, Nader; Vos, Erik; Hübner, Simon; van Veldhuizen, Eddie; van Dijk, Jan; Nijdam, Sander; Kroesen, Gerrit
In this paper, a detailed investigation of the spatio-temporal dynamics of a pulsed microwave plasma is presented. The plasma is ignited inside a dielectric tube in a repetitively pulsed regime at pressures ranging from 1 up to 100 mbar with pulse repetition frequencies from 200 Hz up to 500 kHz. Various diagnostic techniques are employed to obtain the main plasma parameters both spatially and with high temporal resolution. Thomson scattering is used to obtain the electron density and mean electron energy at fixed positions in the dielectric tube. The temporal evolution of the two resonant and two metastable argon 4s states are measured by laser diode absorption spectroscopy. Nanosecond time-resolved imaging of the discharge allows us to follow the spatio-temporal evolution of the discharge with high temporal and spatial resolution. Finally, the temporal evolution of argon 4p and higher states is measured by optical emission spectroscopy. The combination of these various diagnostics techniques gives deeper insight on the plasma dynamics during pulsed microwave plasma operation from low to high pressure regimes. The effects of the pulse repetition frequency on the plasma ignition dynamics are discussed and the plasma-off time is found to be the relevant parameter for the observed ignition modes. Depending on the delay between two plasma pulses, the dynamics of the ionization front are found to be changing dramatically. This is also reflected in the dynamics of the electron density and temperature and argon line emission from the plasma. On the other hand, the (quasi) steady state properties of the plasma are found to depend only weakly on the pulse repetition frequency and the afterglow kinetics present an uniform spatio-temporal behavior. However, compared to continuous operation, the time-averaged metastable and resonant state 4s densities are found to be significantly larger around a few kHz pulsing frequency.
Excited level populations and excitation kinetics of nonequilibrium ionizing argon discharge plasma of atmospheric pressure
Akatsuka, Hiroshi [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, 2-12-1-N1-10, O-Okayama, Meguro-ku, Tokyo 152-8550 (Japan)
Population densities of excited states of argon atoms are theoretically examined for ionizing argon plasma in a state of nonequilibrium under atmospheric pressure from the viewpoint of elementary processes with collisional radiative model. The dependence of excited state populations on the electron and gas temperatures is discussed. Two electron density regimes are found, which are distinguished by the population and depopulation mechanisms for the excited states in problem. When the electron impact excitation frequency for the population or depopulation is lower than the atomic impact one, the electron density of the plasma is considered as low to estimate the population and depopulation processes. Some remarkable characteristics of population and depopulation mechanisms are found for the low electron density atmospheric plasma, where thermal relaxation by atomic collisions becomes the predominant process within the group of close-energy states in the ionizing plasma of atmospheric pressure, and the excitation temperature is almost the same as the gas temperature. In addition to the collisional relaxation by argon atoms, electron impact excitation from the ground state is also an essential population mechanism. The ratios of population density of the levels pairs, between which exists a large energy gap, include information on the electron collisional kinetics. For high electron density, the effect of atomic collisional relaxation becomes weak. For this case, the excitation mechanism is explained as electron impact ladderlike excitation similar to low-pressure ionizing plasma, since the electron collision becomes the dominant process for the population and depopulation kinetics.
Observations of neutral depletion and plasma acceleration in a flowing high-power argon helicon plasma
Denning, C. Mark; Wiebold, Matt; Scharer, John E. [Electrical and Computer Engineering Department, University of Wisconsin-Madison, Engineering Research Building, 1500 Engineering Dr., Madison, Wisconsin 53704 (United States)
Neutral depletion effects are observed in a steady-state flowing argon helicon plasma with a magnetic nozzle for high rf input powers (up to 3 kW). Noninvasive diagnostics including 105 GHz microwave interferometry and optical spectroscopy with collisional-radiative modeling are used to measure the electron density (n{sub e}), electron temperature (T{sub e}), and neutral density (n{sub n}). A region of weak neutral depletion is observed upstream of the antenna where increasing rf power leads to increased electron density (up to n{sub e}=1.6x10{sup 13} cm{sup -3}) while T{sub e} remains essentially constant and low (1.7-2.0 eV). The downstream region exhibits profound neutral depletion (maximum 92% line-averaged ionization), where T{sub e} rises linearly with increasing rf power (up to 4.9 eV) and n{sub e} remains constrained (below 6.5x10{sup 12} cm{sup -3}). Flux considerations indicate accelerated plasma flow (Mach 0.24) through the antenna region due to an axial pressure gradient with reduced collisional drag from neutral depletion.
Surface modification of ultra-high molecular weight polyethylene (UHMWPE) by argon plasma
NASA Astrophysics Data System (ADS)
Liu, Hengjun; Pei, Yanan; Xie, Dong; Deng, Xingrui; Leng, Y. X.; Jin, Yong; Huang, Nan
In this work, argon (Ar) plasma generated by microwave electron cyclotron resonance (MWECR) has been used to modify the UHMWPE in order to increase the wear resistance. The results showed that the wettability, anti-scratch and wear resistance of UHMWPE treated by the Ar plasma had been improved, comparing with native UHMWPE. The FTIR and XPS spectra indicated the improvement of wettability should come from the oxygen based functional groups generated on the surface of UHMWPE. The improvement of anti-scratch and wear resistance may come from the enhancement of crosslinking of UHMWPE by Ar plasma treatment.
Experimental Investigation of Laser-sustained Plasma in Supersonic Argon Flow
Sperber, David; Eckel, Hans-Albert [DLR - German Aerospace Center, Institute of Technical Physics, Stuttgart (Germany); Moessinger, Peter [University of Applied Sciences, Faculty of Mechanical Engineering, Esslingen (Germany); Fasoulas, Stefanos [University of Stuttgart, Institute of Space Systems, Stuttgart (Germany)
Laser-induced energy deposition is widely discussed as a flow control technique in supersonic transportation. In case of thermal laser-plasma upstream of a blunt body, a substantial adaptation of shock wave geometry and magnitude of wave drag is predicted. Related to the research on laser supported detonation, the paper describes the implementation of laser-sustained plasma in a supersonic Argon jet. The stable plasma state is generated by the intersection of a Q-switched Nd:YAG-laser and a continuous wave CO{sub 2}-laser beams, for ignition and maintenance of the plasma respectively. A miniature supersonic Ludwieg tube test facility generates a supersonic jet at velocities of Mach 2.1. Modifications of the flow and plasma conditions are investigated and characterized by Schlieren flow visualisation, laser energy transmission and plasma radiation measurements. The results include the discussions of the flow field as well as the required laser and gas parameters.
Analysis of low alloy and stainless steels by inductively coupled argon plasma spectrometer: Final report
Reimer, H.
Eleven elements in low alloy and stainless steels were analyzed using separate sampling and excitation analysis (SSEA). This solid sampling device is used in conjunction with an inductively coupled argon plasma (ICAP) optical emission spectrometer. Samples are eroded by a controlled spark, and the metal aerosol caused by the erosion is swept into an argon plasma to be excited. This short study was undertaken to provide an alternate method of analysis in case of instrument failure during the usual procedure employed in the laboratory. Accuracy and precision studies also were performed. Precision was determined by analyzing the same sample 11 times. Five certified standards used as samples were analyzed to determine accuracy. The precision and confidence intervals were calculated. The precision as percent relative standard deviation ranged from 8.4 percent for aluminum at a concentration of 0.008 percent to 0.48 percent at 27 percent for chromium. 1 ref., 3 tabs.
Plasma Diagnostics on a Pulsed Argon ICP Source
Dejoseph Jr.; Wei Guo
A planar inductively coupled plasma (ICP) source is characterized using current and voltage probes, a commercially-built Langmuir probe system, and a fast photomultiplier with narrow band filter. The rf supply operates at 13.56 MHz and can be 100% power modulated to allow pulsed operation of the source. By digitally recording long current and voltage waveforms and using accurate phase correction
Application of a hybrid collisional radiative model to recombining argon plasmas
D. A. Benoy; J. A. M. van der Mullen; B. van der Sijde; D. C. Schram
A collisional radiative model, in which a hybrid cut-off technique is used, is applied to recombining plasmas to study the atomic state distribution (ASDF) and the recombination coefficient. Computations of the ASDF using semi-empirical rate coefficients of Vriens and Smeets (V-S) and Drawin (D) are compared with experimental values measured at various positions in a free expanding argon arc jet.
Comparison of atmospheric-pressure helium and argon plasmas generated by capacitively coupled radio-frequency discharge
Li, S.-Z.; Lim, J.-P.; Kang, Jung G.; Uhm, Han S. [State Key Laboratory of Materials Modification by Laser, Ion and Electron Beams and Department of Physics, Dalian University of Technology, Dalian 116024 (China); Department of Molecular Science and Technology, Ajou University, San 5 Wonchon-Dong, Youngtong-Gu, Suwon 443-749 (Korea, Republic of)
In this paper, the electrical discharge characteristics of plasmas generated in coaxial cylindrical electrodes capacitively powered by a radio-frequency power supply at atmospheric pressure are investigated with respect to helium and argon gases. The electrical discharge parameters, voltage (V), current (I), and power (P), are measured for both helium and argon plasmas, and the electron temperatures and electron densities for them are evaluated by means of the equivalent circuit model and the power balance equation. By comparison of the discharge characteristics of the helium and argon plasmas, it is found that the discrepant macroscopic characteristics of helium and argon plasma, viz., current and voltage characteristics and current and power characteristics, are owed to their own intrinsic microscopic parameters of the helium and argon atoms, such as the first excited energy, the ionization energy, the total cross section, and the atom mass. Furthermore, the influences of the additive gas, oxygen gas, on the electrical discharge characteristics are also investigated in the helium and argon plasmas, which are closely related to the electron temperature of plasmas.
Two-dimensional argon metastable density measurements in a radio frequency plasma reactor by planar laser-induced Jluorescence imaging
Zachariah, Michael R.
Two-dimensional argon metastable density measurements in a radio frequency plasma reactor by planar American Institute of Physics. INTRODUCTION Low-pressure, radio-frequency (rf) plasmas are used ex at developing a better understanding of the chemistry and physics in these plasmas. The majority of gas
Ion Transport in Chlorine\\/Argon ECR Plasma
M. Lampe; G. Joyce; R. F. Fernsler; W. M. Manheimer; S. P. Slinker
We have used the quasineutral particle simulation code QUASI-rz (which includes Monte Carlo and Langevin representations of the relevant charged-neutral and charged-charged collision processes) to study transport and distributions of various species in an axisymmetric ECR reactor, operating with pressures on the order of a few mTorr and plasma density up to the order of 10^12 cm-3. In this high-density
Ion Transport in Chlorine/Argon ECR Plasma*
NASA Astrophysics Data System (ADS)
Lampe, M.; Joyce, G.; Fernsler, R. F.; Manheimer, W. M.; Slinker, S. P.
We have used the quasineutral particle simulation code QUASI-rz (which includes Monte Carlo and Langevin representations of the relevant charged-neutral and charged-charged collision processes) to study transport and distributions of various species in an axisymmetric ECR reactor, operating with pressures on the order of a few mTorr and plasma density up to the order of 10^12 cm-3. In this high-density electronegative plasma, ion-ion Coulomb collisions play an important role, since positive and negative ions are driven in opposite directions by the potential gradients, but are strongly coupled by collisions. The velocity distributions of both negative and positive ions are significantly isotropized as a result of ion-ion collisions, and negative ions also contribute to the heating of all heavy species. The kinetics of the plasma is spatially varying and is controlled by the interplay of species transport and a number of processes, including dissociative recombination of Cl_2^+ ions, recombination and collisional detachment of Cl^ ions, and wall recombination of atomic Cl. Densities and distribution functions of various species will be shown, at different locations in the reactor and for operating times up to 500 msec. *Work sponsored by the Office of Naval Research
Comparison between experiment and simulation for argon inductively coupled plasma
NASA Astrophysics Data System (ADS)
Gao, Fei; Zhao, Shu-Xia; Li, Xiao-Song; Wang, You-Nian
In order to include the nonlocal characteristics of electrons and investigate the inductively coupled plasma (ICP) resources more completely, we have developed a hybrid Monte Carlo (MC)/fluid hybrid model and calculated the axial and radial distributions of electron density, electron temperature, plasma potential, and electron energy distribution functions (EEDFs) of Ar discharge in a planar ICP. Furthermore, to make the model more practical, we still incorporate the effects of metastable atoms, whose sets of rate coefficients and density are, respectively, calculated through the electron MC part and fluid module. Besides, the corresponding Langmuir probe measurements are used to compare these data to validate the simulated results. Under all the selected discharge powers and pressures, the theoretically simulated and experimentally measured quantity profiles agree reasonably with each other, embodied in the generally identical magnitude ranges and spatial distributions. Furthermore, the interpretations about their detailed differences are given, which are based on the designs of both experimental schematic and model configuration. The analysis implements that the inclusions of electron-electron collision and a neutral density distribution into the hybrid model are likely to improve the comparison between the model predictions and experiment diagnostics. Furthermore, the evolution of plasma parameters and EEDFs with discharge conditions is discussed.
Investigating the effect of Argon Pressure on DC and High Power Magnetron Plasmas
NASA Astrophysics Data System (ADS)
Bernales, Baysha; Bolat, Rustem; Anders, Andre; Slack, Jonathan; PAG Team; EETD Team
Smart Glass is fabricated by depositing thin films of specialized material onto a transparent substrate. When a potential is applied across the surface of the Smart Glass, it changes its optical properties. Direct Current Magnetron Sputtering (DCMS) and High Power Impulse Magnetron Sputtering (HiPIMS) are two methods of PVD that are used to fabricate this material. In previous research, it has been noted that magnetron plasmas have localized ionization zones that rotate clockwise in DCMS and counterclockwise in HiPIMS. Not much is known about what causes the change in rotation. This research seeks to investigate what occurs during the first moments of plasma evolution. Both DC and high power magnetron plasmas were observed as Argon pressure was varied. It was found that pressure had a very pronounced effect on the floating-point potential signal that was received from the probes placed in the plasma. It was found that when a high-pressure jet of Argon was injected into the system, that the rotation pattern of the DC magnetron plasma was disrupted. It was also found that at certain pressures, the voltage signal was less indicative of azimuthal rotation and more indicative of z-direction breathing modes.
Electrical Aspects of Argon Micro-Cell Plasma with Applications in Bio-Medical Technology
NASA Astrophysics Data System (ADS)
Horiuchi, Yasuhiro; van Dijk, Jan; Makabe, Toshiaki
Argon micro-cell plasma (MCP) is believed to be a viable tool for performing micro-surgery. The non-thermal nature of the discharge allows an effective treatment of pathological tissue without causing thermal damage to its surroundings. This bio-medical application imposes a number of design challenges on the plasma configuration which we will address by computer-aided source design. In this contribution we present a numerical study with the Relaxation ConTinuum model (RCT) [1-2] of the characteristics of an atmospheric argon MCP which is maintained by an RF source. The focus will be on the influence of the geometry and the externally applied RF amplitude and frequency on the plasma properties. In particular, attention will be paid to the effect of pulsed-mode operation on the gas temperature. In addition, the influence of the frequency and the field in the wall sheath on the losses of the plasma species to the cell walls by drift-diffusion processes will be considered. [1] K. Okazaki, T. Makabe and Y. Yamaguchi, Appl. Phys. Lett. (54), 1742 (1989) [2] T. Makabe, "Advances in Low Temperature RF Plasmas" Elsevier, (2002)
Kinetic simulations of argon dusty plasma afterglow including metastable atom kinetics
Alexandrov, A. L., E-mail: firstname.lastname@example.com; Schweigert, I. V.; Ariskin, D. A. [Siberian Branch of the Russian Academy of Sciences, Institute of Theoretical and Applied Mechanics (Russian Federation)
The afterglow of a dusty plasma of rf discharge in argon is simulated by the particle-in-cell-Monte Carlo collision (PIC-MCC) method. The experimental observation that heavy dust contamination of plasma leads to an anomalous increase in the electron density at the beginning of afterglow is explained by release of electrons from the dust surface. Under the assumption that the floating potential of particles is in equilibrium with plasma conditions, the fast cooling of electrons in afterglow plasma due to a rapid escape of hot electrons from the volume leads to a decrease in the magnitude of the floating potential and hence to a loss of charge by dust. The intensive desorption of electrons from nanoparticles is the origin of anomalous behavior of the electron density. At the next stage of afterglow, when the electrons become cool, the plasma decay is defined by ambipolar diffusion. The effect of metastable argon atoms is also considered. Additional ionization due to metastable atom collisions affects the electron temperature but does not change the behavior of the electron density qualitatively.
Characteristics of argon plasma waveguide produced by alumina capillary discharge for short wavelength laser application
Higashiguchi, Takeshi; Yugami, Noboru [Department of Advanced Interdisciplinary Sciences, Center for Optical Research and Education (CORE), and Optical Technology Innovation Center (OpTIC), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Japan Science and Technology Agency, CREST, 4-1-8 Honcho, Kanagawa, Saitama 332-0012 (Japan); Bobrova, Nadezhda; Sasorov, Pavel [Institute for Theoretical and Experimental Physics, B. Cheremushkinskaya Str. 25, 117218 Moscow (Russian Federation); Sakai, Shohei [Department of Advanced Interdisciplinary Sciences, Center for Optical Research and Education (CORE), and Optical Technology Innovation Center (OpTIC), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Sentoku, Yasuhiko [Department of Physics, University of Nevada, Mail Stop 220, Reno, Nevada 89506 (United States); Kodama, Ryosuke [Japan Science and Technology Agency, CREST, 4-1-8 Honcho, Kanagawa, Saitama 332-0012 (Japan); Graduate School of Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan)
We have reported the argon (Ar) plasma waveguide produced in an alumina (Al{sub 2}O{sub 3}) capillary discharge and used to guide ultrashort laser pulses at intensities of the order of 10{sup 16} W/cm{sup 2}. The electron density in the plasma waveguide was measured to be 1x10{sup 18} cm{sup -3}, in agreement with one-dimensional magnetrohydrodynamic (MHD) simulations. The MHD code was also used to evaluate the degree of ionization of argon (Ar) in the preformed plasma waveguide. The maximum ion charge state of Ar{sup 3+} in capillary discharge was measured and obtained in the MHD simulations. The spectrum of the propagated laser pulse in the Ar plasma waveguide was not modified and was well reproduced by a particle-in-cell simulations under initial ion charge state of Ar{sup 3+} in the preformed plasma waveguide. The optimum timing for the laser pulse injection was around 150 ns after initiation of a discharge with a peak current of 200 A.
A new air-cooled argon/helium-compatible inductively coupled plasma torch.
Miyahara, Hidekazu; Iwai, Takahiro; Kaburaki, Yuki; Kozuma, Tomokazu; Shigeta, Kaori; Okino, Akitoshi
A new inductively coupled plasma (ICP) torch with an air-cooling system has been designed and developed for both argon and helium plasma. The same torch and impedance-matching network could be used to generate stable Ar- and He-ICP. The torch consists of three concentric quartz tubes. The carrier gas, plasma gas, and cooling gas flow through the intervals between each tube. In an experiment, it was found that Ar-ICP could form a stable plasma under the following conditions: RF power of 1 kW, plasma gas flow rate of 11 L min(-1), and cooling gas flow rate of 20 L min(-1). For He-ICP, an input RF power of 2 kW, which is two-times higher than that of a conventional He-ICP, could be constantly applied to the plasma with plasma gas and cooling gas flow rates of 15 and 20 L min(-1), respectively. Using this torch, it is possible to realize lower plasma gas consumption for Ar- and He-ICP and a high-power drive for He-ICP. It has been found that the air-cooling gas stabilizes the shape of the plasma due to the pressure difference between the cooling gas and the plasma gas. PMID:24521909
Normal and abnormal evolution of argon metastable density in high-density plasmas
NASA Astrophysics Data System (ADS)
Seo, B. H.; Kim, J. H.; You, S. J.
A controversial problem on the evolution of Ar metastable density as a function of electron density (increasing trend versus decreasing trend) was resolved by discovering the anomalous evolution of the argon metastable density with increasing electron density (discharge power), including both trends of the metastable density [Daltrini et al., Appl. Phys. Lett. 92, 061504 (2008)]. Later, by virtue of an adequate physical explanation based on a simple global model, both evolutions of the metastable density were comprehensively understood as part of the abnormal evolution occurring at low- and high-density regimes, respectively, and thus the physics behind the metastable evolution has seemed to be clearly disclosed. In this study, however, a remarkable result for the metastable density behavior with increasing electron density was observed: even in the same electron density regime, there are both normal and abnormal evolutions of metastable-state density with electron density depending on the measurement position: The metastable density increases with increasing electron density at a position far from the inductively coupled plasma antenna but decreases at a position close to the antenna. The effect of electron temperature, which is spatially nonuniform in the plasma, on the electron population and depopulation processes of Argon metastable atoms with increasing electron density is a clue to understanding the results. The calculated results of the global model, including multistep ionization for the argon metastable state and measured electron temperature, are in a good agreement with the experimental results.
Reduction of a collisional-radiative mechanism for argon plasma based on principal component analysis
NASA Astrophysics Data System (ADS)
Bellemans, A.; Munafò, A.; Magin, T. E.; Degrez, G.; Parente, A.
This article considers the development of reduced chemistry models for argon plasmas using Principal Component Analysis (PCA) based methods. Starting from an electronic specific Collisional-Radiative model, a reduction of the variable set (i.e., mass fractions and temperatures) is proposed by projecting the full set on a reduced basis made up of its principal components. Thus, the flow governing equations are only solved for the principal components. The proposed approach originates from the combustion community, where Manifold Generated Principal Component Analysis (MG-PCA) has been developed as a successful reduction technique. Applications consider ionizing shock waves in argon. The results obtained show that the use of the MG-PCA technique enables for a substantial reduction of the computational time.
Effect of the electron energy distribution on total energy loss with argon in inductively coupled plasmas
NASA Astrophysics Data System (ADS)
Kim, June Young; Kim, Young-Cheol; Kim, Yu-Sin; Chung, Chin-Wook
The total energy lost per electron-ion pair lost ?T is investigated with the electron energy distribution function (EEDF). The EEDFs are measured at various argon powers in RF inductively coupled plasma, and the EEDFs show a depleted distribution (a discontinuity occurring at the minimum argon excitation threshold energy level) with the bulk temperature and the tail temperature. The total energy loss per electron-ion pair lost ?T is calculated from a power balance model with the Maxwellian EEDFs and the depleted EEDFs and then compared with the measured ?T from the floating probe. It is concluded that the small population of the depleted high energy electrons dramatically increases the collisional energy loss, and the calculated ?T from the depleted EEDFs has a value that is similar to the measured ?T.
Polydiagnostic calibration performed on a low pressure surface wave sustained argon plasma
NASA Astrophysics Data System (ADS)
de Vries, N.; Palomares, J. M.; Iordanova, E. I.; van Veldhuizen, E. M.; van der Mullen, J. J. A. M.
The electron density and electron temperature of a low pressure surface wave sustained argon plasma have been determined using passive and active (laser) spectroscopic methods simultaneously. In this way the validity of the various techniques is established while the plasma properties are determined more precisely. The electron density, ne, is determined with Thomson scattering (TS), absolute continuum measurements, Stark broadening and an extrapolation of the atomic state distribution function (ASDF). The electron temperature, Te, is obtained using TS and absolute line intensity (ALI) measurements combined with a collisional-radiative (CR) model for argon. At an argon pressure of 15 mbar, the ne values obtained with TS and Stark broadening agree with each other within the error bars and are equal to (4 ± 0.5) × 1019 m-3, whereas the ne value (2 ± 0.5) × 1019 m-3 obtained from the continuum is about 30% lower. This suggests that the used formula and cross-section values for the continuum method have to be reconsidered. The electron density determined by means of extrapolation of the ASDF to the continuum is too high (~1020 m-3). This is most probably related to the fact that the plasma is strongly ionizing so that the extrapolation method is not justified. At 15 mbar, the Te values obtained with TS are equal to 13 400 ± 1100 K while the ALI/CR-model yields an electron temperature that is about 10% lower. It can be concluded that the passive results are in good or fair agreement with the active results. Therefore, the calibrated passive methods can be applied to other plasmas in a similar regime for which active diagnostic techniques cannot be used.
Argon Micro-Cell Plasma with Applications in Bio-Medical Technology
NASA Astrophysics Data System (ADS)
van Dijk, Jan; Horiuchi, Yasuhiro; Makabe, Toshiaki
In bio-medical technology, plasmas have recently been acknowledged as a viable instrument for performing micro-surgery. This in-vivo application obviously demands strict compatibility with the human tissue which is to be treated. That in turn imposes strict requirements on the pressure (1 atmosphere) and gas temperature (37 C) in which the plasma operates. In addition, the plasma source must be compact and reliable, while the plasma species should not poison the body fluids with which they are in contact. In this contribution we will discuss the plasma-physical and electrical properties of an RF-operated argon micro-cell plasma (MCP) configuration which is believed to be able to meet these design restrictions. Results of a numerical study with the help of the two-dimensional Relaxation ConTinuum (RCT) model [1-2] will be presented. We shall focus on the spatial variation of the feed gas temperature for various plasma operating conditions. Special attention will be paid to the volumetric and surface heating mechanisms. [1] T. Makabe, N. Nakano and Y. Yamaguchi, Phys. Rev. A (45), 2520 (1992) [2] T. Makabe, "Advances in Low Temperature RF Plasmas" Elsevier, (2002)
Effects of substrate bias and argon flux on the structure of titanium nitride films deposited by filtered cathodic arc plasma
Y. J. Zhang; P. X. Yan; Z. G. Wu; W. W. Zhang; G. A. Zhang; W. M. Liu; Q. J. Xue
High-quality titanium nitride (TiN) films with nano-structure were prepared at ambient temperature on (111) silicon substrates by filtered cathodic arc plasma (FCAP) technology with an in-plane S filter. The effects of substrate bias and argon flux on the crystal grain size, roughness and preferred orientation were systematically investigated. It was found that the substrate bias and argon flux can affect
Laser-Induced Fluorescence for Sheath Characterization in Low-Density Argon Plasmas
NASA Astrophysics Data System (ADS)
Englesbe, Alexander C.; Sawlani, Kapil U.; Foster, John E.
Laser-induced fluorescence (LIF) spectroscopy has become a standard non-intrusive diagnostic technique for determining the energies and concentrations of ion and neutral species in plasmas. A limitation of this technique, however, is the small signal-to-noise ratio incurred when interrogating relatively low-density plasmas. This problem is exacerbated when examining regions such as the sheath at an electrode immersed in the plasma. If ion energetics within the sheath are of interest, then in principle thicker sheaths are desirable in that for a given laser spot size, the potential structure can be inferred with high resolution. We present a methodology for accomplishing LIF in the sheath of a low-temperature argon plasma with an electron density of the order 107 -108 cm-3. This diagnostic is being developed for the purpose of studying the effect of secondary electron emission on sheath potential behavior in low-density plasmas. The plasma in this study is produced in a multipole ring-cusp ion source. A tunable diode laser excites the Ar II transition at 668.61 nm, which fluoresces at 442.72 nm. The LIF measurements of the ion density are corroborated with electrostatic probes at fixed locations, and the ion velocity distribution within the sheath is determined. Laser-induced fluorescence (LIF) spectroscopy has become a standard non-intrusive diagnostic technique for determining the energies and concentrations of ion and neutral species in plasmas. A limitation of this technique, however, is the small signal-to-noise ratio incurred when interrogating relatively low-density plasmas. This problem is exacerbated when examining regions such as the sheath at an electrode immersed in the plasma. If ion energetics within the sheath are of interest, then in principle thicker sheaths are desirable in that for a given laser spot size, the potential structure can be inferred with high resolution. We present a methodology for accomplishing LIF in the sheath of a low-temperature argon plasma with an electron density of the order 107 -108 cm-3. This diagnostic is being developed for the purpose of studying the effect of secondary electron emission on sheath potential behavior in low-density plasmas. The plasma in this study is produced in a multipole ring-cusp ion source. A tunable diode laser excites the Ar II transition at 668.61 nm, which fluoresces at 442.72 nm. The LIF measurements of the ion density are corroborated with electrostatic probes at fixed locations, and the ion velocity distribution within the sheath is determined. Work supported by AFOSR Grant No. FA9550-09-1-0695.
Excitation temperature measurements in an argon-CO{sub 2} thermal plasma
Maouhoub, E.; Coitout, H.; Parizet, M.J.
The CO{sub 2} molecule is used in several plasma processes and is of special interest in the thermal treatment of organic waste. The excitation temperature is measured in an argon-CO{sub 2} thermal plasma by optical emission spectroscopy. The theoretical calculations of concentration used to determine excitation temperature and also the numerical Abel inversion are presented. The effect of CO{sub 2} molecule upon this plasma is studied as a function of the Ar-CO{sub 2} mixture composition and discharge current. The excitation temperature is ranging from 7,000 K to 11,000 K, and excitation temperature gradient from 200 K/mm to 600 K/mm.
A radio-frequency nonequilibrium atmospheric pressure plasma operating with argon and oxygen
NASA Astrophysics Data System (ADS)
Moravej, M.; Yang, X.; Hicks, R. F.; Penelon, J.; Babayan, S. E.
A capacitively coupled, atmospheric pressure plasma has been developed that produces a high concentration of reactive species at a gas temperature below 300 °C. The concentration of ground-state oxygen atoms produced by the discharge was measured by NO titration, and found to equal 1.2 vol %, or 1.2+/-0.4×1017 cm-3, using 6.0 vol % O2 in argon at 150 W/cm3. The ozone concentration determined at the same conditions was 4.3+/-0.5×1014 cm-3. A model of the gas phase reactions was developed and yielded O atom and O3 concentrations in agreement with experiment. This plasma source etched Kapton® at 5.0 ?m/s at 280 °C and an electrode-to-sample spacing of 1.5 cm. This fast etch rate is attributed to the high O atom flux generated by the plasma source.
The role of visible and resonance radiation in the energy balance of LTE plasma in argon
NASA Astrophysics Data System (ADS)
Golubovskii, Yu B.; Maiorov, V. A.; Gorchakov, S.; Uhrlandt, D.
Energy losses due to radiation in an LTE arc plasma in argon are investigated in the temperature range from 5000 to 15?000 K. Calculations of the radiation transport require us to know the absorption spectra; for that purpose, free–free, bound–free and bound–bound transitions are taken into account. The energy losses due to resonance transitions with large absorption coefficients are analyzed. The transport of visible radiation with small absorption coefficients is calculated by accurate integration over a whole spectrum. The resonance radiation transport in LTE plasma is described by the Biberman–Holstein equation, which is usually used in non-equilibrium plasma. As the temperature grows, radiation processes become the main channel of energy losses. It is shown that, despite the resonance radiation being trapped, the energy losses due to resonance radiation escape can achieve 10% of the total radiation losses.
Molecular ion formation in decaying plasmas produced in pure argon and krypton
NASA Astrophysics Data System (ADS)
Grössl, M.; Langenwalter, M.; Helm, H.; Märk, T. D.
The formation of molecular ions Ar2+ and Kr2+ in decaying plasmas of the respective rare gases is studied at pressures between 0.2 and 3 Torr at room temperature. Measurements of the decay of He2+ in He are made to test the experimental technique used. The reaction rate coefficient for the process Ar+(2P3/2)+2 Ar?Ar2++Ar is found to be (2.35±0.2)×10-31 cm6 s-1. The corresponding reaction rate coefficient in krypton is found to be (2.2±0.2)×10-31 cm6 s-1. Using a recently proposed reaction model [Helm and Varney (1978)] for the excited fine structure state (2P1/2), the pressure dependence of the reaction rate coefficient describing the destruction Ar+(2P1/2)+2Ar?products is calculated. The pressure dependence and magnitude of the coefficient found are in agreement with the experimental findings of Liu and Conway (1975) for the above process. The process could not be studied experimentally in our system due to the low density of Ar+(2P1/2) in our discharge. The low density is inferred indirectly and the process responsible for the fast removal of the excited ion species in the argon plasma is regarded to be the superelastic collision process with slow plasma electrons Ar+(2P1/2)+e?Ar+(2P3/2)+e+0.18 eV for which a rate coefficient ?10-7 cm3 s-1 is estimated. At late times in the afterglow a significant source of ionization is observed in argon. This source is consistent with ionizing collisions of metastable argon atoms. Its importance increased with pressure since the diffusive loss of metastable atoms becomes insignificant as the pressure is raised.
Investigation of forbidden transitions in argon ions. [in laboratory plasma for solar corona simulation
NASA Technical Reports Server (NTRS)
Jalufka, N. W.
An attempt has been made to observe the visible forbidden argon coronal lines at 553.6 nm (Ar X), 691.7 nm (Ar XI), 847.6 nm (Ar XIII), and 441.2 nm (Ar XIV) in a deuterium-argon plasma produced in a large theta pinch. The electron temperature (250 eV) and the electron density (5 by 10 to the 16th power per cu cm) were measured by Thomson scattering of ruby laser radiation. This temperature is adequate to produce ionization stages up to Ar XIV, as was verified by photographic observation of Ar XIV lines. No line corresponding to the coronal lines was observed from the high-temperature plasma, but lines with wavelengths very nearly identical to those of two of the forbidden transitions were observed; these lines were due to allowed transitions of Ar II in a cooler portion of the plasma. Calculation of rate coefficients in the Coulomb-Born approximation shows that for laboratory experiments, electron collisions are much more important than radiative decay in depopulating the upper state of the forbidden lines.
Argon–oxygen dc magnetron discharge plasma probed with ion acoustic waves
Saikia, Partha, E-mail: firstname.lastname@example.com; Saikia, Bipul Kumar; Goswami, Kalyan Sindhu [Centre of Plasma Physics, Institute for Plasma Research, Nazirakhat, Sonapur, Kamrup, Assam 782 402 (India); Phukan, Arindam [Madhabdev College, Narayanpur, Lakhimpur, Assam 784164 (India)
The precise determination of the relative concentration of negative ions is very important for the optimization of magnetron sputtering processes, especially for those undertaken in a multicomponent background produced by adding electronegative gases, such as oxygen, to the discharge. The temporal behavior of an ion acoustic wave excited from a stainless steel grid inside the plasma chamber is used to determine the relative negative ion concentration in the magnetron discharge plasma. The phase velocity of the ion acoustic wave in the presence of negative ions is found to be faster than in a pure argon plasma, and the phase velocity increases with the oxygen partial pressure. Optical emission spectroscopy further confirms the increase in the oxygen negative ion density, along with a decrease in the argon positive ion density under the same discharge conditions. The relative negative ion concentration values measured by ion acoustic waves are compared with those measured by a single Langmuir probe, and a similarity in the results obtained by both techniques is observed.
Waves generated in the vicinity of an argon plasma gun in the ionosphere
NASA Technical Reports Server (NTRS)
Cahill, L. J., Jr.; Arnoldy, R. L.; Lysak, R. L.; Peria, W.; Lynch, K. A.
Wave and particle observations were made in the close vicinity of an argon plasma gun carned to over 600 km altitude on a sounding rocket. The gun was carned on a subpayload, separated from the main payload early in the flight. Twelve-second argon ion ejections were energized alternately with a peak energy of 100 or 200 eV. They produced waves, with multiple harmonics, in the range of ion cyclotron waves, 10 to 1000 Hz at rocket altitudes. Many of these waves could not be identified as corresponding to the cyclotron frequencies of any of the ions, argon or ambient, known to be present. In addition, the wave frequencies were observed to rise and fall and to change abruptly during a 12-s gun operation. The wave amplitudes, near a few hundred Hertz, were of the order of O. 1 V/m. Some of the waves may be ion-ion hybrid waves. Changes in ion populations were observed at the main payload and at the subpayload during gun operations. A gun-related, field-aligned, electron population also appeared.
Spectroscopic study of a long high-electron-density argon plasma column generated at atmospheric pressure
Li Shouzhe; Huang Wentong; Wang Dezhen [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, and School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023 (China)
A stable plasma column is generated in a quartz tube using a pair of hollow electrodes driven by a sinusoidal power supply of 45 kHz at atmospheric pressure in argon. Two distinct operating modes (low-current and high-current modes) are identified through observing its discharge phenomena, measuring its electrical characteristics, and determining the gas temperatures by spectroscopic diagnosis of Q branch of UV OH spectrum. The electron density in the high-current mode is diagnosed by Stark broadening and is found to be two orders higher than that in low-current mode.
Thermodynamic properties and transport coefficients of arc lamp plasmas: argon, krypton and xenon
NASA Astrophysics Data System (ADS)
Murphy, Anthony B.; Tam, Eugene
Calculated values of the density, specific heat, enthalpy, viscosity, thermal conductivity and electrical conductivity of thermal plasmas formed from three gases used in arc lamps, krypton, argon and xenon, are presented. The calculations, which assume local thermodynamic equilibrium, were performed for pressures from 1 to 100 atm and for the temperature range 300-30?000 K. The results were compared with those of previously published studies. Some discrepancies were found for krypton and xenon; these are attributed to the improved values of the collision integrals used here in calculating the transport coefficients.
Effect of neutral gas heating in argon radio frequency inductively coupled plasma
NASA Astrophysics Data System (ADS)
Chin, O. H.; Jayapalan, K. K.; Wong, C. S.
Heating of neutral gas in inductively coupled plasma (ICP) is known to result in neutral gas depletion. In this work, this effect is considered in the simulation of the magnetic field distribution of a 13.56 MHz planar coil ICP. Measured electron temperatures and densities at argon pressures of 0.03, 0.07 and 0.2 mbar were used in the simulation whilst neutral gas temperatures were heuristically fitted. The simulated results showed reasonable agreement with the measured magnetic field profile.
Determination of trace impurities in uranium hexafluoride by an inductively coupled argon plasma spectrometer
Short, B.W.; Spring, H.S.; Grant, R.L.
A procedure has been developed to determine 21 trace impurity elements in uranium hexafluoride, using inductively coupled argon plasma emission spectrometry (ICAP). The method consists of a liquid-liquid extraction to separate uranium from the trace impurities with a mixture of tri-(2-ethyl-hexyl)-phosphate (TEHP) and heptane. The raffinate containing the elements is subsequently analyzed by ICAP. The impurity elements which can be analyzed by this method are: Al, B, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Na, Ni, Pb, Sb, Sn, Ti, V and Zn.
Numerical simulations of a nonequilibrium argon plasma in a shock-tube experiment
NASA Technical Reports Server (NTRS)
Cambier, Jean-Luc
A code developed for the numerical modeling of nonequilibrium radiative plasmas is applied to the simulation of the propagation of strong ionizing shock waves in argon gas. The simulations attempt to reproduce a series of shock-tube experiments which will be used to validate the numerical models and procedures. The ability to perform unsteady simulations makes it possible to observe some fluctuations in the shock propagation, coupled to the kinetic processes. A coupling mechanism by pressure waves, reminiscent of oscillation mechanisms observed in detonation waves, is described. The effect of upper atomic levels is also briefly discussed.
Theoretical study of nanoparticle formation in thermal plasma processing: Nucleation, coagulation and aggregation
NASA Astrophysics Data System (ADS)
Mendoza Gonzalez, Norma Yadira
This work presents a mathematical modeling study of the synthesis of nanoparticles in radio frequency (RF) inductively coupled plasma (ICP) reactors. The purpose is to further investigate the influence of process parameters on the final size and morphology of produced particles. The proposed model involves the calculation of flow and temperature fields of the plasma gas. Evaporation of raw particles is also accounted with the particle trajectory and temperature history calculated with a Lagrangian approach. The nanoparticle formation is considered by homogeneous nucleation and the growth is caused by condensation and Brownian coagulation. The growth of fractal aggregates is considered by introducing a power law exponent Df. Transport of nanoparticles occurs by convection, thermophoresis and Brownian diffusion. The method of moments is used to solve the particle dynamics equation. The model is validated using experimental results from plasma reactors at laboratory scale. The results are presented in the following manner. First, use is made of the computational fluid dynamics software (CFD), Fluent 6.1 with a commercial companion package specifically developped for aerosols named: Fine Particle Model (FPM). This package is used to study the relationship between the operating parameters effect and the properties of the end products at the laboratory scale. Secondly, a coupled hybrid model for the synthesis of spherical particles and fractal aggregates is developped in place of the FPM package. Results obtained from this model will allow to identify the importance of each parameter in defining the morphology of spherical primary particles and fractal aggregates of nanoparticles. The solution of the model was made using the geometries and operating conditions of existing reactors at the Centre de Recherche en Energie, Plasma et Electrochimie (CREPE) of the Universite de Sherbrooke, for which experimental results were obtained experimentally. Additionally, this study demonstrates the importance of the flow and temperature fields on the growth of fractal particles; namely the aggregates.
Theoretical study on the electron energy distribution function and electron transport parameters of argon plasma
NASA Astrophysics Data System (ADS)
Zhang, Yachun; He, Xiang; Chen, Jianping; Lu, Jian; Ni, Xiaowu; Shen, Zhonghua
Fluid model of argon plasma require the input of transport parameters that depend on the electron energy distribution function (EEDF). The EEDF and electron transport parameters of reduced field and electric field frequency in argon plasma are investigated by solving the Boltzmann equation with the two-term approximation. It is found that the EEDF closes to Druyvesteyn distribution and decreases sharply after several eV when the reduced field is less than 10Td. The low energy part of EEDF flats with the reduced field, and the high energy tail of EEDF increases with the reduced field. The EEDF approaches to dual temperature Maxwellian distribution when the reduced field is larger than 50Td. When the reduced field is larger than 300Td, the high energy tail of EEDF decreases more slowly than Maxwellian distribution, and the shape of EEDF tends to concave. The electron mobility decreases with the reduced field, and tends to a const . The electron diffusion coefficient increases with the reduced field, but exists a local minimum at 50Td. The relationship between EEDF and electric field frequency shows that the EEDF approaches to Maxwellian distribution in a high frequency field because of the collision with electrons and neutral particles. In this case, the electron mobility and diffusion coefficient are complex number, and the imaginary parts raise with the field frequency. The absolute value of transport parameters decrease with the field frequency.
Diagnostics of the influence of levitating microparticles on the radiofrequency argon plasma
NASA Astrophysics Data System (ADS)
Pustylnik, Mikhail Y.; Mitic, Slobodan; Klumov, Boris A.; Morfill, Gregor E.
The effect of a levitating cloud of microparticles on the parameters of a radiofrequency (RF) plasma has been studied by means of two experimental techniques. Axial distributions of 1 s excited states of argon were measured by a self-absorption method. A correction of a standard self-absorption method for the extinction of the light by the levitating microparticles is proposed. In addition the electron temperature was estimated using the optical emission spectroscopy. Measurements at the same discharge conditions in a microparticle-free discharge and discharge, containing a cloud of levitating microparticles, revealed the non-local influence of the microparticle cloud on the discharge plasma. The most probable cause of this influence is the disturbance of the ionization balance by the levitating microparticles.
Deposition of a-SiC:H using organosilanes in an argon/hydrogen plasma
Maya, L.
Selected organosilanes were examined as precursors for the deposition of amorphous hydrogenated silicon carbide in an argon/hydrogen plasma. Effect of process variables on the quality of the films was established by means of FTIR, Auger spectroscopy, XPS, XRD, chemical analysis, and weight losses upon pyrolysis. For a given power level there is a limiting feeding rate of the precursor under which operation of the system is dominated by thermodynamics and leads to high quality silicon carbide films that are nearly stoichiometric and low in hydrogen. Beyond that limit, carbosilane polymer formation and excessive hydrogen incorporation takes place. The hydrogen content of the plasma affects the deposition rate and the hydrogen content of the film. In the thermodynamically dominated regime the nature of the precursor has no effect on the quality of the film, it affects only the relative utilization efficiency.
Microwave diagnostic for the determination of the electron temperature of a low density shock-heated argon plasma
NASA Technical Reports Server (NTRS)
Schneider, C. P.; Exberger, R. J.
The diffraction, defocusing and beam bending effects of microwaves transmitted through a bounded shock-heated argon plasma with low electron density are investigated with the purpose of developing an accurate method for electron temperature (Te) determination. This report describes the evaluation technique and presents results for an argon plasma with pressure between 3 and 10 torr, and T2 between 5500 and 9500 K. The electron temperature values obtained have a range of uncertainty between -20% and +10% only. The electron temperature is equal or lower by approximately 1000 K in comparison to the heavy particle temperature (T2).
Ontogenetic variation of metalloproteinases and plasma coagulant activity in venoms of wild Bothrops atrox specimens from Amazonian rain forest
Jorge Luis López-Lozano; Marcelo Valle de Sousa; Carlos André O Ricart; Carlos Chávez-Olortegui; Eladio Flores Sanchez; Emiro G Muniz; Paulo F Bührnheim; Lauro Morhy
A comparative study of venoms from juvenile, sub-adult and adult wild Bothrops atrox specimens captured in Manaus region (Brazil) was performed. All venoms tested had acidic pH (5.5) and the human plasma coagulant activity was higher in venoms from juvenile and sub-adult specimens than in adults. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) showed that the most intense bands in adult
Simulation of DBD plasma actuators, and nanoparticle-plasma interactions in argon-hydrogen CCP RF discharges
NASA Astrophysics Data System (ADS)
Mamunuru, Meenakshi
The focus of this work is modeling and simulation of low temperature plasma discharges (LTPs). The first part of the thesis consists of the study of dielectric barrier (DBD) plasma actuators. Use of DBD plasma actuators on airfoil surfaces is a promising method for increasing airfoil efficiency. Actuators produce a surface discharge that causes time averaged thrust in the neutral gas. The thrust modifies the boundary layer properties of the flow and prevents the occurrence of separation bubbles. In simulating the working of an actuator, the focus is on the spatial characteristics of the thrust produced by the discharge over very short time and space scales. The results provide an understanding of the causes of thrust, and the basic principles behind the actuator operation. The second part of this work focusses on low pressure plasma discharges used for silicon nanoparticle synthesis. When reactive semiconductor precursor gases are passed through capacitively coupled plasma (CCP) radio frequency (RF) reactors, nano sized particles are formed. When the reactors are operated at high enough powers, a very high fraction of the nanoparticles are crystallized in the chamber. Nanoparticle crystallization in plasma is a very complex process and not yet fully understood. It can be inferred from experiments that bulk and surface processes initiated due to energetic ion impaction of the nanoparticles are responsible for reordering of silicon atoms, causing crystallization. Therefore, study of plasma-particle interactions is the first step towards understanding how particles are crystallized. The specific focus of this work is to investigate the experimental evidence that hydrogen gas presence in argon discharges used for silicon nanocrystal synthesis, leads to a superior quality of nanocrystals. Influence of hydrogen gas on plasma composition and discharge characteristics is studied. Via Monte Carlo simulation, distribution of ion energy impacting particles surface is studied. It is seen that hydrogen ions cause a reduction in particle floating potential, thereby lowering the ion impaction energies. The hydrogen ion current is also effective in delivering increased number of atomic H radicals to the particle surface, which are known to promote particle crystallization. The work therefore sheds light on the ways in which trace amount of hydrogen gas participates in silicon nanoparticle crystallization in argon silane plasma.
Temporally and spatially resolved characterization of microwave induced argon plasmas: Experiment and modeling
Baeva, M., E-mail: email@example.com; Andrasch, M.; Ehlbeck, J.; Loffhagen, D.; Weltmann, K.-D. [INP Greifswald, Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany)
Experiments and modeling of the plasma-microwave interaction have been performed in a coaxial microwave plasma source at a field frequency of 2.45 GHz generating argon plasmas at pressures of 20 and 40 millibars and a ratio of flow rate to pressure of 0.125 sccm/Pa. The incident microwave power between 100?W and 300?W is supplied in a regime of a pulse-width modulation with cycle duration of 110?ms and a power-on time of 23?ms. The experiments are based on heterodyne reflectometry and microwave interferometry at 45.75?GHz. They provide the temporal behaviour of the complex reflection coefficient, the microwave power in the plasma, as well as the electron density in the afterglow zone of the discharge. The self-consistent spatially two-dimensional and time-dependent modeling complements the analysis of the plasma-microwave interaction delivering the plasma and electromagnetic field parameters. The consolidating experimental observations and model predictions allow further characterizing the plasma source. The generated plasma has a core occupying the region close to the end of the inner electrode, where maximum electron densities above 10{sup 20}?m{sup ?3} and electron temperatures of about 1?eV are observed. Due to a longer outer electrode of the coaxial structure, the plasma region is extended and fills the volume comprised by the outer electrode. The electron density reaches values of the order of 10{sup 19}?m{sup ?3}. The heating of the gas occurs in its great part due to elastic collisions with the plasma electrons. However, the contribution of the convective heating is important especially in the extended plasma region, where the gas temperature reaches its maximum values up to approximately 1400?K. The temporally and spatially resolved modeling enables a thorough investigation of the plasma-microwave interaction which clearly shows that the power in-coupling occurs in the region of the highest electron density during the early stage of the discharge. In the steady state phase, however, the power in-coupling occurs close to the source walls where the electron density is significantly lower than on the discharge axis.
Temporally and spatially resolved characterization of microwave induced argon plasmas: Experiment and modeling
NASA Astrophysics Data System (ADS)
Baeva, M.; Andrasch, M.; Ehlbeck, J.; Loffhagen, D.; Weltmann, K.-D.
Experiments and modeling of the plasma-microwave interaction have been performed in a coaxial microwave plasma source at a field frequency of 2.45 GHz generating argon plasmas at pressures of 20 and 40 millibars and a ratio of flow rate to pressure of 0.125 sccm/Pa. The incident microwave power between 100 W and 300 W is supplied in a regime of a pulse-width modulation with cycle duration of 110 ms and a power-on time of 23 ms. The experiments are based on heterodyne reflectometry and microwave interferometry at 45.75 GHz. They provide the temporal behaviour of the complex reflection coefficient, the microwave power in the plasma, as well as the electron density in the afterglow zone of the discharge. The self-consistent spatially two-dimensional and time-dependent modeling complements the analysis of the plasma-microwave interaction delivering the plasma and electromagnetic field parameters. The consolidating experimental observations and model predictions allow further characterizing the plasma source. The generated plasma has a core occupying the region close to the end of the inner electrode, where maximum electron densities above 1020 m-3 and electron temperatures of about 1 eV are observed. Due to a longer outer electrode of the coaxial structure, the plasma region is extended and fills the volume comprised by the outer electrode. The electron density reaches values of the order of 1019 m-3. The heating of the gas occurs in its great part due to elastic collisions with the plasma electrons. However, the contribution of the convective heating is important especially in the extended plasma region, where the gas temperature reaches its maximum values up to approximately 1400 K. The temporally and spatially resolved modeling enables a thorough investigation of the plasma-microwave interaction which clearly shows that the power in-coupling occurs in the region of the highest electron density during the early stage of the discharge. In the steady state phase, however, the power in-coupling occurs close to the source walls where the electron density is significantly lower than on the discharge axis.
Large Amplitude Shear Alfvén Waves and a Local Density Perturbation in an Argon Plasma
NASA Astrophysics Data System (ADS)
Palmer, Nathan E.; Gekelman, Walter
Large amplitude shear Alfvén waves (B_wave/B0 ~ 10-3) and the propagation of a local density perturbation have been studied using a diverse combination of diagnostics in the Large Plasma Device at UCLA. The waves are launched from an inductive antenna that drives current along the the background magnetic field (B_0), and they propagate along the axis of a 9m long, 0.5m diameter cylindrical argon plasma. Typical plasma parameters are n_e=1.4×10^12 cm-3, T_e=4 eV, T_i=1 eV, and B_0=1500 G. Laser-induced fluorescence (LIF) measurements at many spatial locations give a detailed description of the ion motion---i.e., the time-resolved 2D ion velocity distributions in several planes perpendicular to B_0. These are combined with extensive probe measurements of B_wave to compute E_wave, which includes a B-field-aligned component. The velocity distributions and wave field measurements are further correlated with probe measurements of n_e, T_e, and ion saturation current to track the density perturbation near the center of the wave pattern and yield a detailed picture of the wave-particle interaction as well as the overall evolution of the plasma.
Modelling of carbon dust formation by cluster growth in argon plasmas
NASA Astrophysics Data System (ADS)
Bonnin, X.; Lombardi, G.; Hassouni, K.; Michau, A.; Bénédic, F.; Arnas, C.
In tokamaks with carbon plasma-facing components, one can observe the presence of nano-sized dust particles. Understanding such dust particle formation is a prerequisite to any attempt to limit or avoid this dust that may be responsible for tritium retention and pollution of the plasma. We report on coupled modeling of carbon chemistry and dust particle nucleation, growth, and transport in a plasma discharge. The chemical model used for carbon cluster dust growth is described in detail. The results are consistent with measurements made at LPIIM from low-pressure argon DC discharges in a stainless steel reactor with a graphite cathode [C. Arnas, C. Dominique, P. Roubin et al., J. Nucl. Mater. 337-339 (2005) 69], serving as a proxy for the tokamak plasma edge. The time evolution of the 'large' dust particles consists of a nucleation phase followed by an accretion phase. These reach a dust grain size of 40 nm on a timescale comparable to the experimental observations (minutes to hours).
Modeling the effect of dust on the plasma parameters in a dusty argon discharge under microgravity.
Akdim, M R; Goedheer, W J
A dusty radio-frequency argon discharge is simulated with the use of a two-dimensional fluid model. In the model, discharge quantities, such as the fluxes, densities, and electric field are calculated self-consistently. The charge and density of the dust are calculated with an iterative method. During the transport of the dust, its charge is kept constant in time. The dust influences the electric potential distribution through its charge and the density of the plasma through recombination of positive ions and electrons on its surface. Results are presented for situations in which the dust significantly changes the discharge characteristics, both by a strong reduction of the electron density and by altering the electric potential by its charge. Simulations for dust particles having a radius of 7.5 microm show that a double space charge layer is created around the sharp boundary of the dust crystal. A central dust-free region (void) is created by the ion drag force. Inside this void a strong increase of the production of argon metastables is found. This phenomenon is in agreement with experimental observations, where an enhanced light emission is seen inside the void. PMID:16241359
Scanning-electron-microscopy study of argon-plasma-treated and untreated peel-test Kevlar 49/epoxy laminates
Ingraham, J.A.; Walton, J.; Pruneda, C.O.; Morgan, R.J.
It is concluded that a 200-watt RF argon plasma treatment of Kevlar fibers for four minutes increases the fiber/epoxy interfacial bonding. However, as a consequence of this increase in fiber-matrix bonding, the fiber is readily fibrillated during laminate deformation and failure.
This limited project was conducted to determine the usefulness of the D.C. argon plasma for the analysis of wastewater. Seven priority pollutant elements, arsenic (As), beryllium (Be), cadmium (Cd), chromium (Cr), nickel (Ni), lead (Pb), and thallium (Tl), were selected for use i...
Dynamics of plasma expansion and shockwave formation in femtosecond laser-ablated aluminum plumes in argon gas at atmospheric pressures
Harilal, S. S.
in argon gas at atmospheric pressures Alexander Miloshevsky, Sivanandan S. Harilal, Gennady Miloshevsky formation in fs-pulse and ns-pulse laser ablated Al plumes in an ambient gas at atmospheric pressures. VC plasma expansion into a background gas at atmospheric pressure is cru- cial for many engineering
Development of a diffuse air-argon plasma source using a dielectric-barrier discharge at atmospheric pressure
Tang Jie; Jiang Weiman; Zhao Wei; Wang Yishan; Li Shibo; Wang Haojing [State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an 710119 (China)] [State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an 710119 (China); Duan Yixiang [State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an 710119 (China) [State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an 710119 (China); Research Center of Analytical Instrumentation, Sichuan University, Chengdu 610064 (China)
A stable diffuse large-volume air plasma source was developed by using argon-induced dielectric-barrier discharges at atmospheric pressure. This plasma source can be operated in a filamentary discharge with the average areal power density of 0.27 W/cm{sup 2} and the gas temperature of 315{+-}3 K. Spatial measurement of emission spectrum and temperature indicates that this plasma is uniform in the central region along the transverse direction. It is also found that the formation of diffuse air plasma mainly lies in the creation of sufficient seed electrons by the Penning effect through collisions between two argon or nitrogen metastables at low electric fields.
Exploring the electron density in plasmas induced by extreme ultraviolet radiation in argon
NASA Astrophysics Data System (ADS)
van der Horst, R. M.; Beckers, J.; Osorio, E. A.; Banine, V. Y.
The new generation of lithography tools use high energy EUV radiation which ionizes the present background gas due to photoionization. To predict and understand the long term impact on the highly delicate mirrors, it is essential to characterize these kinds of EUV-induced plasmas. We measured the electron density evolution in argon gas during and just after irradiation by a short pulse of EUV light at 13.5?nm by applying microwave cavity resonance spectroscopy. Dependencies on EUV pulse energy and gas pressure have been explored over a range relevant for industrial applications. Our experimental results show that the maximum reached electron density depends linearly on pulse energy. A quadratic dependence caused by photoionization and subsequent electron impact ionization by free electrons is found from experiments where the gas pressure is varied. This is demonstrated by our theoretical estimates presented in this manuscript as well.
Exploring the electron density in plasmas induced by extreme ultraviolet radiation in argon
van der Horst, R M; Osorio, E A; Banine, V Y
The new generation of lithography tools use high energy EUV radiation which ionizes the present background gas due to photoionization. To predict and understand the long term impact on the highly delicate mirrors It is essential to characterize these kinds of EUV-induced plasmas. We measured the electron density evolution in argon gas during and just after irradiation by a short pulse of EUV light at 13.5 nm by applying microwave cavity resonance spectroscopy. Dependencies on EUV pulse energy and gas pressure have been explored over a range relevant for industrial applications. Our experimental results show that the maximum reached electron density depends linearly on pulse energy. A quadratic dependence - caused by photoionization and subsequent electron impact ionization by free electrons - is found from experiments where the gas pressure is varied. This is demonstrated by our theoretical estimates presented in this manuscript as well.
Effect of dielectric wall temperature on plasma plume in an argon atmospheric pressure discharge
Song, Jian; Huo, Yuxin; Wang, Youyin; Yu, Daren, E-mail: firstname.lastname@example.com [School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Tang, Jingfeng; Wei, Liqiu [Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, Harbin 150001 (China)
In this letter, the effect of the dielectric wall temperature on the length and volume of an atmospheric pressure plasma jet (APPJ) is investigated using a single-electrode configuration driven with an AC power supply. To distinguish the APPJ status from the argon flow rate, the three modes, laminar, transition, and turbulent, are separated. When the dielectric wall is heated, the APPJ length and volume are enhanced. Also, the transition regions remarkably expand over a large range of flow rates. The results indicate that different factors contribute to the expansion of the transition region. The increase in the radial and axial velocities is the main cause of the expansion of the transition region to the low-velocity region. The expansion to the high-velocity region is dominantly induced by a change in the viscosity.
Energy spectrum of argon ions emitted from Filippov type Sahand plasma focus
Mohammadnejad, M.; Pestehe, S. J.; Mohammadi, M. A. [Department of Atomic and Molecular Physics, Faculty of Physics, University of Tabriz, Postal Code 5166614766, Tabriz (Iran, Islamic Republic of) [Department of Atomic and Molecular Physics, Faculty of Physics, University of Tabriz, Postal Code 5166614766, Tabriz (Iran, Islamic Republic of); Research Institute for Applied Physics and Astronomy, University of Tabriz, Tabriz (Iran, Islamic Republic of)
The energy and flux of the argon ions produced in Sahand plasma focus have been measured by employing a well-designed Faraday cup. The secondary electron emission effects on the ion signals are simulated and the dimensions of Faraday cup are optimized to minimize these effects. The measured ion energy spectrum is corrected for the ion energy loss and charge exchange in the background gas. The effects of the capacitor bank voltage and working gas pressure on the ion energy spectrum are also investigated. It has been shown that the emitted ion number per energy increases as the capacitor bank voltage increases. Decreasing the working gas pressure leads to the increase in the number of emitted ion per energy.
Energy spectrum of argon ions emitted from Filippov type Sahand plasma focus.
Mohammadnejad, M; Pestehe, S J; Mohammadi, M A
The energy and flux of the argon ions produced in Sahand plasma focus have been measured by employing a well-designed Faraday cup. The secondary electron emission effects on the ion signals are simulated and the dimensions of Faraday cup are optimized to minimize these effects. The measured ion energy spectrum is corrected for the ion energy loss and charge exchange in the background gas. The effects of the capacitor bank voltage and working gas pressure on the ion energy spectrum are also investigated. It has been shown that the emitted ion number per energy increases as the capacitor bank voltage increases. Decreasing the working gas pressure leads to the increase in the number of emitted ion per energy. PMID:23902061
Ionization in inductively coupled argon plasmas studied by optical emission spectroscopy
Lee, Young-Kwang; Chung, Chin-Wook [Department of Electrical Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of)
Contribution of stepwise ionization to total ionization was experimentally investigated in low-pressure inductively coupled argon plasmas. In the pressure range 3-50 mTorr, optical emission spectroscopy was employed to determine metastable fractions (metastable density relative to ground state density) by measuring the emission intensity of selected lines. The measured metastable fractions were in good agreement with the calculation, showing a dependence on the discharge pressure. The rate of stepwise ionization was estimated from the excited level densities (measurements and model predictions) and their ionization rate coefficients. It is observed that at relatively low discharge pressures (<10 mTorr) the ionization is mainly provided by the direct ionization, whereas at higher pressure the stepwise ionization is predominant with increasing absorbed power.
Application of a hybrid collisional radiative model to recombining argon plasmas
NASA Astrophysics Data System (ADS)
Benoy, D. A.; van der Mullen, J. A. M.; van de Sanden, M. C. M.; van der Sijde, B.; Schram, D. C.
A collisional radiative model, in which a hybrid cut-off technique is used, is applied to recombining plasmas to study the atomic state distribution (ASDF) and the recombination coefficient. Computations of the ASDF using semi-empirical rate coefficients of Vriens and Smeets (V-S) and Drawin (D) are compared with experimental values measured at various positions in a free expanding argon arc jet. Apart from the shock position, where the calculated results are too low, the model calculations are higher than the experimental results. The volumetric recombination coefficient has a Te exp -4 and a Te exp -4.8 dependence when semiempirical rate coefficients of, respectively, V-S and D are used. The differences between the models based on the rate coefficients of V-S and D indicate that the recombination flow is sensitive to the low temperature behavior of the rate coefficients.
Flow of a thermally nonequilibrium argon plasma in the arc of a plasmatron with expansion into a vacuum chamber
I. G. Panevin; A. S. Vojnovskij; A. G. Kostylev; V. V. Novomlinskij
Subsonic and supersonic flows of an argon plasma in a plasmatron and an adjacent vacuum chamber are investigated experimentally and analytically for pressures of 10 exp 2 - 10 exp 4 Pa and a current of 800 A. The parameters of the electric arc plasma are calculated by using a single-fluid two-temperature model based on a full system of Navier-Stokes
Direct solid atomic emission spectrometric analysis of metal samples by an argon microwave plasma torch coupled to spark ablation
U. Engel; A. Kehden; E. Voges; J. A. C. Broekaert
Spark ablation has been combined to microwave plasma torch atomic emission spectrometry for the direct analysis of compact metallic samples. The material is ablated by a medium voltage spark (450 V, 370 Hz) in a point-to-plane configuration and swept into a 100-W, 2.45-GHz argon microwave discharge. The microwave plasma is observed end-on and the radiation analysed with a polychromator. The
Effects of MASP-1 of the Complement System on Activation of Coagulation Factors and Plasma Clot Formation
Hess, Katharina; Ajjan, Ramzi; Phoenix, Fladia; Dobó, József; Gál, Péter; Schroeder, Verena
Background Numerous interactions between the coagulation and complement systems have been shown. Recently, links between coagulation and mannan-binding lectin-associated serine protease-1 (MASP-1) of the complement lectin pathway have been proposed. Our aim was to investigate MASP-1 activation of factor XIII (FXIII), fibrinogen, prothrombin, and thrombin-activatable fibrinolysis inhibitor (TAFI) in plasma-based systems, and to analyse effects of MASP-1 on plasma clot formation, structure and lysis. Methodology/Principal Findings We used a FXIII incorporation assay and specific assays to measure the activation products prothrombin fragment F1+2, fibrinopeptide A (FPA), and activated TAFI (TAFIa). Clot formation and lysis were assessed by turbidimetric assay. Clot structure was studied by scanning electron microscopy. MASP-1 activated FXIII and, contrary to thrombin, induced FXIII activity faster in the Val34 than the Leu34 variant. MASP-1-dependent generation of F1+2, FPA and TAFIa showed a dose-dependent response in normal citrated plasma (NCP), albeit MASP-1 was much less efficient than FXa or thrombin. MASP-1 activation of prothrombin and TAFI cleavage were confirmed in purified systems. No FPA generation was observed in prothrombin-depleted plasma. MASP-1 induced clot formation in NCP, affected clot structure, and prolonged clot lysis. Conclusions/Significance We show that MASP-1 interacts with plasma clot formation on different levels and influences fibrin structure. Although MASP-1-induced fibrin formation is thrombin-dependent, MASP-1 directly activates prothrombin, FXIII and TAFI. We suggest that MASP-1, in concerted action with other complement and coagulation proteins, may play a role in fibrin clot formation. PMID:22536427
Effect of process parameters on properties of argon–nitrogen plasma for titanium nitride film deposition
Saikia, Partha; Kakati, Bharat [Centre of Plasma Physics, Institute for Plasma Research, Nazirakhat, Sonapur-782 402, Kamrup, Assam (India)] [Centre of Plasma Physics, Institute for Plasma Research, Nazirakhat, Sonapur-782 402, Kamrup, Assam (India)
In this study, the effect of working pressure and input power on the physical properties and sputtering efficiencies of argon–nitrogen (Ar/N{sub 2}) plasma in direct current magnetron discharge is investigated. The discharge in Ar/N{sub 2} is used to deposit TiN films on high speed steel substrate. The physical plasma parameters are determined by using Langmuir probe and optical emission spectroscopy. On the basis of the different reactions in the gas phase, the variation of plasma parameters and sputtering rate are explained. A prominent change of electron temperature, electron density, ion density, and degree of ionization of Ar is found as a function of working pressure and input power. The results also show that increasing working pressure exerts a negative effect on film deposition rate while increasing input power has a positive impact on the same. To confirm the observed physical properties and evaluate the texture growth as a function of deposition parameters, x-ray diffraction study of deposited TiN films is also done.
Improving Resolution of Confocal Laser Induced Fluorescence in Argon Helicon Plasma
NASA Astrophysics Data System (ADS)
Soderholm, Mark; Vandervort, Robert; Scime, Earl; McKee, John; McCarren, Dustin
Laser Induced Fluorescence (LIF) provides measurements of flow speed, temperature and when absolutely calibrated, density of ions or neutrals in a plasma. Traditionally, laser induced fluorescence requires two ports on a plasma device. One port is used for laser injection and the other is used for fluorescence emission collection. Traditional LIF is tedious and time consuming to align. These difficulties motivate the development of an optical configuration that requires a single port and remains fully aligned at all times; confocal LIF. Our confocal optical design employs a single two inch diameter lens to both inject the laser light and collect the stimulated emission from an argon plasma. A dichroic mirror is used to separate the injected laser light from the collected emission. The measurement location is scanned radially by manually adjusting the final focusing lens position. In the initial version of the confocal optical system, measurements were poorly resolved radially because they were integrated over a fairly large path length (~4 cm) centered at the focal point. Here we present collected data from a modified configuration that significantly improves the special resolution of confocal measurements. The confocal measurements are compared to traditional, two-port, LIF measurements over the same radial range.
Secondary electron emission induced by fast argon neutrals and its effects on rf plasmas
NASA Astrophysics Data System (ADS)
Bojarov, Aleksandar; Radmilovic-Radjenovic, Marija; Petrovic, Zoran Lj.
In this paper we have examined a dual-frequency rf discharge in argon that is strongly affected by the secondary emission of electrons from the electrodes. We have used implicit ``Particle In Cell'' code as a tool for investigation of different electrode surface conditions that define the secondary emission. For precise description of the secondary emission we use analytic formulas suggested by Phelps and Petrovic (Plasma Sources Sci. Technol 8, R21, 1999). Two surface conditions, atomically ``clean'' and ``dirty,'' describe the secondary emission as a function of the energy of impacting ion or atom on the electrode. In dual-frequency discharges one of the electrodes usually has some voltage bias, thus leading to greater production of fast neutrals on its side. Since on the biased electrode ion and neutral fluxes are greater than on the powered electrode, the secondary emission from biased electrode has a greater effect on the plasma. Results from our simulations show that secondary emitting fast neutrals can greatly affect the plasma, especially in discharges with intense production of neutrals in the sheath. We conclude that for precise description of rf discharges a realistic modeling of the secondary emission induced by ions and fast neutrals is necessary.
Vacuum ultraviolet photon fluxes in argon-containing inductively coupled plasmas
NASA Astrophysics Data System (ADS)
Radovanov, S. B.; Persing, H. M.; Wang, S.; Culver, C. L.; Boffard, J. B.; Lin, C. C.; Wendt, A. E.
Vacuum ultraviolet (VUV) photons emitted from excited atomic states are ubiquitous in material processing plasmas. Damage of materials is induced by energy transfer from the VUV photons to the surface, causing disorder in the surface region, surface reactions, and affecting bonds in the material bulk. Monitoring of the surface flux of VUV photons from inductively coupled plasmas (ICP) and its dependence on discharge parameters is thus highly desirable. Results of non-invasive, direct windowless VUV detection using a photosensitive diode will be presented. Relative VUV fluxes were also obtained using a sodium salicylate coating on the inside of a vacuum window, converting VUV into visible light detected through the vacuum window. The coating is sensitive to wavelengths in the range 80-300 nm, while the photodiode is only sensitive to wavelengths below 120 nm. In argon the VUV emissions are primarily produced by spontaneous decay from 3p5 4 s resonance levels (1s2,1s4) and may be reabsorbed by ground state atoms. Real-time resonance level concentrations were measured and used to predict the VUV photon flux at the detector for a range of different ICP pressures, powers, and for various admixtures of Ar with N2, and H2. Vacuum ultraviolet (VUV) photons emitted from excited atomic states are ubiquitous in material processing plasmas. Damage of materials is induced by energy transfer from the VUV photons to the surface, causing disorder in the surface region, surface reactions, and affecting bonds in the material bulk. Monitoring of the surface flux of VUV photons from inductively coupled plasmas (ICP) and its dependence on discharge parameters is thus highly desirable. Results of non-invasive, direct windowless VUV detection using a photosensitive diode will be presented. Relative VUV fluxes were also obtained using a sodium salicylate coating on the inside of a vacuum window, converting VUV into visible light detected through the vacuum window. The coating is sensitive to wavelengths in the range 80-300 nm, while the photodiode is only sensitive to wavelengths below 120 nm. In argon the VUV emissions are primarily produced by spontaneous decay from 3p5 4 s resonance levels (1s2,1s4) and may be reabsorbed by ground state atoms. Real-time resonance level concentrations were measured and used to predict the VUV photon flux at the detector for a range of different ICP pressures, powers, and for various admixtures of Ar with N2, and H2. This work was supported in part by NSF grant PHY-1068670.
Drugs Modifying Nitric Oxide Metabolism Affect Plasma Cholesterol Levels, Coagulation Parameters, Blood Pressure Values and the Appearance of Plasma Myocardial Necrosis Markers in Rabbits: Opposite Effects of L-NAME and Nitroglycerine
Arnaldo Pinelli; Silvio Trivulzio; Livio Tomasoni; Boris Bertolini; Sergio Brenna; Edgardo Bonacina; Roberto Accinni
Various experiments have shown that decreased nitric oxide values alter plasma lipid levels or coagulation parameters or blood pressure values or cause myocardial necrosis phenomena, but it is not clear whether these alterations are reciprocally connected, or whether nitric oxide changes are involved in the appearance of some coronary disease risk factors (lipid, coagulation, blood pressure alterations) and myocardial necrosis.
Determining the effect of freezing on coagulation testing: comparison of results between fresh and once frozen-thawed plasma.
Gosselin, Robert C; Dwyre, Denis W
The accuracy of the results from coagulation testing can be affected by numerous preanalytic and analytic variables including the stability of the citrated sample at room temperature. Samples not tested within 2-4?h of collection should be processed and frozen for later analysis. As limited data exist about the impact of freezing samples on coagulation testing, we sought to evaluate the effect of freezing on coagulation testing. Plasma samples into 3.2% sodium citrate tubes, centrifuged to yield platelet-poor plasma, were evaluated for prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen, D-dimer, antithrombin (AT) activity, factors V, VII, VIII, IX, lupus anticoagulant and anti-Xa measurements for both unfractionated and low-molecular-weight heparins. Samples were then frozen at -70°C for at least 1 week and testing was repeated using the same lot of material. All tests strongly correlated (R?>?0.85) between fresh and frozen sample results. Using paired t test analysis, significant differences between fresh and frozen tested plasma existed for PT, APTT, factors V, VIII and AT. Significant differences existed between fresh and frozen lupus anticoagulant ratios (lupus anticoagulant screen but not lupus anticoagulant confirm), and single centrifugation process underestimated the presence of lupus anticoagulant as compared to double centrifugation processing. Freezing significantly affects the results for PT, APTT, factors V and VIII activity, and AT activity, although these differences were not considered to be clinically significant. Double centrifugation is required for accurate lupus anticoagulant testing, regardless of whether platelet-poor plasma is achieved with single centrifugation. PMID:25202883
Correlations between plasma variables and the deposition process of Si films from chlorosilanes in low pressure RF plasma of argon and hydrogen
NASA Technical Reports Server (NTRS)
Avni, R.; Carmi, U.; Grill, A.; Manory, R.; Grossman, E.
The dissociation of chlorosilanes to silicon and its deposition on a solid substrate in a RF plasma of mixtures of argon and hydrogen were investigated as a function of the macrovariables of the plasma. The dissociation mechanism of chlorosilanes and HCl as well as the formation of Si in the plasma state were studied by sampling the plasma with a quadrupole mass spectrometer. Macrovariables such as pressure, net RF power input and locations in the plasma reactor strongly influence the kinetics of dissociation. The deposition process of microcrystalline silicon films and its chlorine contamination were correlated to the dissociation mechanism of chlorosilanes and HCl.
Measurements of the populations of metastable and resonance levels in the plasma of an RF capacitive discharge in argon
NASA Astrophysics Data System (ADS)
Vasilieva, A. N.; Voloshin, D. G.; Kovalev, A. S.; Kurchikov, K. A.
The behavior of the populations of two metastable and two lower resonance levels of argon atoms in the plasma of an RF capacitive discharge was studied. The populations were measured by two methods: the method of emission self-absorption and the method based on measurements of the intensity ratios of spectral lines. It is shown that the populations of resonance levels increase with increasing power deposited in the discharge, whereas the populations of metastable levels is independent of the RF power. The distribution of the populations over energy levels is not equilibrium under these conditions. The population kinetics of argon atomic levels in the discharge plasma is simulated numerically. The distribution function of plasma electrons recovered from the measured populations of atomic levels and numerical simulations is found to be non-Maxwellian.
Spatially resolved measurement of hydroxyl radical (OH) concentration in an argon RF plasma jet by planar laser-induced fluorescence
NASA Astrophysics Data System (ADS)
Vorá?, J.; Obrusník, A.; Procházka, V.; Dvo?ák, P.; Talába, M.
A spatially resolved two-dimensional quantitative measurement of OH concentration in an effluent of a radio-frequency-driven atmospheric pressure plasma jet ignited in argon is presented. The measurement is supported by a gas dynamics model which gives detailed information about the spatially resolved gas composition and temperature. The volume in which the OH radicals were found and partially also the total amount of OH radicals increase with the argon flow rate, up to a value for which the flow becomes turbulent. In the turbulent regime, both the emission from the jet and the OH concentration are confined to a smaller volume. The maximum concentration of about 5.4 × 1021 m-3 is reached at the tip of the visible discharge at the flow rate of 0.6 slm and high driving powers. An increase in hydroxyl concentration due to admixing of humid ambient air to the argon flow was observed.
The inactivation of Staphylococcus aureus biofilms using low-power argon plasma in a layer-by-layer approach.
Traba, Christian; Liang, Jun F
The direct application of low power argon plasma for the decontamination of pre-formed Staphylococcus aureus biofilms on various surfaces was examined. Distinct chemical/physical properties of reactive species found in argon plasmas generated at different wattages all demonstrated very potent but very different anti-biofilm mechanisms of action. An in-depth analysis of the results showed that: (1) the different reactive species produced in each plasma demonstrated specific antibacterial and/or anti-biofilm activity; and (2) the commonly associated etching effect could be manipulated and even controlled, depending on the experimental conditions. Under optimal experimental parameters, bacterial cells in S. aureus biofilms were killed (> 99.9%) by plasmas within 10 min of exposure and no bacteria nor biofilm regrowth from argon discharge gas treated biofilms was observed for 150 h. The decontamination ability of plasmas for the treatment of biofilm related contaminations on various materials was confirmed and an entirely novel layer-by-layer decontamination approach was designed and examined. PMID:25569189
Continuum emission-based electron diagnostics for atmospheric pressure plasmas and characteristics of nanosecond-pulsed argon plasma jets
NASA Astrophysics Data System (ADS)
Park, Sanghoo; Choe, Wonho; Kim, Holak; Park, Joo Young
Electron diagnostics based on electron–neutral atom (e–a) bremsstrahlung in the UV and visible range emitted from atmospheric pressure plasmas is presented. Since the spectral emissivity of the e–a bremsstrahlung is determined by electron density (ne) and mean electron temperature (Te) representing the Maxwellian electron energy distribution, their diagnostics is possible. As an example, emission spectra measured from capacitive discharges are presented, which show good agreement with the theoretically calculated emissivity of the e–a bremsstrahlung. For a single pin electrode nanosecond-pulsed plasma jet (n-PPJ) in argon, we investigate the electron properties and the temporal behavior of the positive streamers. Streamers with many branches are clearly observed inside the dielectric tube, while a few main streamers propagate outside the tube along the jet axis. A two-dimensional (2D) measurement of the time-averaged Te distribution was developed using a commercial digital camera and optical band pass filters based on the emissivity ratio of two wavelengths of the e–a bremsstrahlung. The viable measurement range of Te is 0.5–7?eV for the choice of two wavelengths of 300s and 900s?nm and 0.5–4?eV for two wavelengths of 400s and 900s?nm, which are uncontaminated by the atomic and/or molecular spectra. The 2D Te distribution obtained using 514.5 and 632.8?nm emissions helps to reveal the role of electrons in streamer characteristics in the argon n-PPJ. Time-averaged Te of 2.0?eV and 1.0?eV inside and outside the tube, respectively, were measured. The streamer dynamics of the n-PPJ is shown to be dependent on Te.
Characterization of Modified Tapioca Starch in Atmospheric Argon Plasma under Diverse Humidity by FTIR Spectroscopy
NASA Astrophysics Data System (ADS)
Deeyai, P.; Suphantharika, M.; Wongsagonsup, R.; Dangtip, S.
Tapioca is economical crop grown in Thailand and continues to be one of the major sources of starch. Nowadays, tapioca starch has been widely used in industrial applications, however the native form of starch has limited the applications. Thus scientists try to modify the properties of starch for increasing the stability of the granules, pastes to low pH, heat, and shear during the food process. We modify the tapioca starch by plasma treatment under an argon atmosphere. The degree of modification is determined by following water content in the starch granules. The tablet samples of native starch are also prepared and compared with the plasma treated starch. Before plasma treatment, the starch tablets are stored under three different relative humilities (RH) including 11%, 68%, and 78%RH, respectively. The samples are characterized using FTIR spectroscopy associated with the degree of cross-linking. The results show that the water molecules are engulfed into the starch structure in two ways, a tight bond and a weak absorption of water molecules which is represented at two wave number of 1630 cm-1 and 3272 cm-1, respectively. The degree of cross-linking can be identified from the relative intensity of these two peaks with the C—O—H peak at 993 cm-1. The results show that the degree of cross-linking increase in the plasma treated starch. The degree of cross-linking of the treated starch with high relative humidity is less than that of the treated starch with low relative humidity.
Comparison of the transport properties of two-temperature argon plasmas calculated using different methods
NASA Astrophysics Data System (ADS)
Zhang, X. N.; Li, H. P.; Murphy, A. B.; Xia, W. D.
Two main methods have been used to calculate the transport properties of two-temperature (2-T) plasmas in local chemical equilibrium: the method of Devoto (method B), in which coupling between electrons and heavy species is neglected, and the method of Rat et al (method C), in which coupling is included at the cost of a considerable increase in complexity. A new method (method A) has recently been developed, based on the modified Chapman–Enskog solution of the species Boltzmann equations. This method retains coupling between electrons and heavy species by including the electron–heavy-species collision term in the heavy-species Boltzmann equation. In this paper, the properties of 2-T argon plasmas calculated using the three methods are compared. The viscosity, electrical conductivity and translational thermal conductivity obtained using all three methods are very similar. method B does not allow a complete set of species diffusion coefficient to be obtained. It is shown that such a set can be calculated using method A without any significant loss of accuracy. Finally, it is important to note that, by using the physical fact that the mass of heavy particles is much larger than that of electrons (i.e. me?<< mh), the complexity of calculations using method A is not increased compared with method B; that is to say, the calculation procedure is much simpler than with method C.
Spatially resolved Langmuir probe diagnostics in a capacitively coupled radio frequency argon and oxygen plasma
NASA Astrophysics Data System (ADS)
Küllig, C.; Wegner, Th; Meichsner, J.
Axial and radial profiles of the positive ion saturation current were measured by Langmuir probe diagnostics in a capacitively coupled radio frequency (RF) plasma in argon and oxygen. Under certain conditions these profiles provide the spatial density distribution of the positive ions, which corresponds approximately to the electron density in the electropositive plasma. Particularly in oxygen at low RF power a peak in the ion saturation current appears in the radial direction at the electrode boundary. The axial position s at the maximum ion saturation current depends on total pressure with s ? p?1/3, which reveals the pressure dependence of a collisional RF sheath. Furthermore, Langmuir probe characteristics were evaluated in terms of the Druyvesteyn method to determine the radial behavior of the electron energy probability function (EEPF). From the EEPF the radially resolved effective electron temperature and electron density were calculated. The radial electron density profile from the Langmuir probe was numerically integrated to calculate a line integrated electron density for comparison with the measured line integrated density from 160 GHz microwave interferometry. The integration over the Langmuir probe density results in a line integrated density, which amounts to 40% of the line integrated density from microwave interferometry.
The Mechanisms of Coagulation.
ERIC Educational Resources Information Center
Kurtz, Richard; Jesty, Jolyon
Several topics such as heart disease, strokes, biochemical reactions, blood components, and genetics can be related to blood clotting. Introduces a simple, safe and inexpensive hands-on demonstration using bovine (cattle) blood plasma of normal and abnormal coagulation. (ZWH)
New structures for argon-ion laser performance in low pressure discharge plasmas
J. Salk
Argon low pressure arc discharge that is plane-shape stabilized is examined with emphasis on increasing the efficiency of this system as compared to argon-ion lasers with cylindrical, wall-stabilized discharge. Laser power output with cylindrical hollow cathode discharge at higher neutral gas densities and electron energy is considered along with argon low pressure discharge before and between linear formed anodes. The
E-H mode transition in low-pressure inductively coupled nitrogen-argon and oxygen-argon plasmas
Lee, Young Wook; Lee, Hye Lan; Chung, T. H. [Department of Physics, Dong-A University, Busan 604-714 (Korea, Republic of)
This work investigates the characteristics of the E-H mode transition in low-pressure inductively coupled N{sub 2}-Ar and O{sub 2}-Ar discharges using rf-compensated Langmuir probe measurements and optical emission spectroscopy (OES). As the ICP power increases, the emission intensities from plasma species, the electron density, the electron temperature, and the plasma potential exhibit sudden changes. The Ar content in the gas mixture and total gas pressure have been varied in an attempt to fully characterize the plasma parameters. With these control parameters varying, the changes of the transition threshold power and the electron energy distribution function (EEDF) are explored. In N{sub 2}-Ar and O{sub 2}-Ar discharges at low-pressures of several millitorr, the transition thresholds are observed to decrease with Ar content and pressure. It is observed that in N{sub 2}-Ar plasmas during the transition, the shape of the EEDF changes from an unusual distribution with a flat hole near the electron energy of 3 eV in the E mode to a Maxwellian distribution in the H mode. However, in O{sub 2} -Ar plasmas, the EEDFs in the E mode at low Ar contents show roughly bi-Maxwellian distributions, while the EEDFs in the H mode are observed to be nearly Maxwellian. In the E and H modes of O{sub 2}-Ar discharges, the dissociation fraction of O{sub 2} molecules is estimated using optical emission actinometry. During the E-H mode transition, the dissociation fraction of molecules is also enhanced.
Determination of rare earth elements in geological materials by inductively coupled argon plasma\\/atomic emission spectrometry
J. G. Crock; F. E. Lichte
Inductively coupled argon plasma\\/optical emission spectrometry (ICAP\\/OES) is useful as a simultaneous, multielement analytical technique for the determination of trace elements in geological materials. A method for the determination of trace-level rare earth elements (REE) in geological materials using an ICAP 63-channel emission spectrometer is described. Separation and preconcentration of the REE and yttrium from a sample digest are achieved
Behavior of the 398.4nm Hg II Spectral Line in the Helium and Argon Plasmas
NASA Astrophysics Data System (ADS)
Skocic, M.; Burger, M.; Gavrilov, M.; Bukvic, S.; Djenize, S.
The astrophysically important 398.4 nm Hg II spectral line was investigated in the laboratory helium and argon plasmas. The mercury atoms were sputtered from the amalgamated gold cylindrical plates located in the homogenous part of the pulsed discharge. We have found that strong intensity of the 398.4 nm Hg II line is due to excessively high density of the helium metastable atoms.
Preliminary Study on Applications of an Atmospheric-Pressure Argon Plasma Discharge With a Single-Electrode Configuration
Wen-Tong Huang; Shou-Zhe Li
An atmospheric-pressure (AP) argon plasma discharge generated in a single-electrode configuration with the power supply operating at a frequency of 45 kHz is employed to perform some applications, such as the treatment of the interior surface of a medical infusion tube, hydrophilic modification of insulator surface, hardening of metal surface, and acidification treatment of water. It is shown that the
Zinc, lead and copper in human teeth measured by induced coupled argon plasma atomic emission spectroscopy (ICP-AES)
L. T Chew; D. A Bradley; Amin Yusoff Mohd; Maah Mohd Jamil
Inductively Coupled Argon Plasma Atomic Emission Spectroscopy (ICP-AES) has been used to determine Pb, Zn and Cu levels in 47 exfoliated human teeth (all of which required extraction for orthodontic reasons). Lead concentrations for the group were 1.7 ?g (g tooth mass)?1 to 40.5 ?g (g tooth mass)?1, with a median of 9.8 (g (g tooth mass)?1. A median lead level in
Velocity distribution function of sputtered gallium atoms during inductively coupled argon plasma treatment of a GaAs surface
Emilie Despiau-Pujo; Pascal Chabert; Raphaeel Ramos; Gilles Cunge; Nader Sadeghi
A GaN laser diode at 403.3 nm is used to measure the velocity distribution function (vdf) of Ga atoms sputtered from a radio-frequency biased GaAs substrate in a low pressure inductively coupled plasma (ICP) argon discharge. To investigate both perpendicular (V{sub z} normal to wafer) and longitudinal (V parallel to wafer) velocity components, laser induced fluorescence (LIF) measurements are performed
Comparison of functional aspects of the coagulation cascade in human and sea turtle plasmas
Gerald Soslau; Bryan Wallace; Catherine Vicente; Seth J. Goldenberg; Todd Tupis; James Spotila; Robert George; Frank Paladino; Brent Whitaker; Gary Violetta; Rotney Piedra
Functional hemostatic pathways are critical for the survival of all vertebrates and have been evolving for more than 400 million years. The overwhelming majority of studies of hemostasis in vertebrates have focused on mammals with very sparse attention paid to reptiles. There have been virtually no studies of the coagulation pathway in sea turtles whose ancestors date back to the
Assessment of the roles of various inactivation agents in an argon-based direct current atmospheric pressure cold plasma jet
Zhang Qian; Wang Ruixue [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Sun Peng; Feng Hongqing; Liang Yongdong [College of Engineering, Peking University, Beijing 100871 (China); Zhu Weidong [Department of Applied Science and Technology, Saint Peter's College, New Jersey 07031 (United States); Becker, Kurt H. [Department of Applied Physics, Polytechnic Institute of New York University, New York 11201 (United States); Zhang Jue; Fang Jing [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); College of Engineering, Peking University, Beijing 100871 (China)
Three types of gases, pure argon (99.999%), argon with 2% oxygen, and argon with 2% oxygen and 10% nitrogen were used as operating gases of a direct current atmospheric pressure cold plasma jet to inactivate Staphylococcus aureus (S. aureus) suspended in a liquid. The inactivation efficacies for the plasma jets operating in the three gases decrease from Ar/O{sub 2}(2%) to Ar/O{sub 2}(2%)/N{sub 2}(10%) to pure Ar. Optical emission spectroscopy, electron spin resonance spectroscopy, high performance liquid chromatography, and atomic absorption spectrophotometry were employed to identify and monitor the reactive species in the plasma-liquid system for the three operating gases and revealed the presence of O, {sup 1}O{sub 2}, OH, NO, H{sub 2}O{sub 2}, O{sub 3}, and NO{sub 3}{sup -}/NO{sub 2}{sup -} as well as Cu{sup +}/Cu{sup 2+}. The S. aureus inactivation results indicate that atomic oxygen (O) is the key inactivation agent, while other species play a lesser role in the inactivation progress studied here.
Analysis of tungsten carbide coatings by infrared laser-induced argon spark with inductively coupled plasma atomic emission spectrometry
NASA Astrophysics Data System (ADS)
Kanický, V.; Otruba, V.; Mermet, J.-M.
Infrared laser ablation was studied for application to the analysis of plasma-sprayed tungsten carbide/cobalt coatings. The potential of the laser induced argon-spark (LINA-Spark™), as a sample introduction device in inductively coupled plasma atomic emission spectrometry was studied. The use of an IR laser along with defocusing led to laser-induced microplasma-based ablation. The mass ablation rate, represented by the ICP emission intensity per laser beam unit area, exhibited a flat increase in the irradiance range 2-250 GW/cm 2. A low slope (0.5) of this dependence in log-log scale gave evidence of plasma shielding. The steep increase in the measured acoustic signal when focused in front of the sample, i.e. in argon, indicated a breakdown of argon. Consequently, considerably lower ICP emissions were observed within the same range of irradiance. The cobalt/tungsten line intensity ratio in the ICP was practically constant from 1.5 up to at least 250 GW/cm 2. Acceptable precision (R.S.D.<5%) was obtained without internal standardization for irradiance between 2 and 8 GW/cm 2. Optimization of the laser pulse energy, repetition rate, beam focusing and sample displacement during interaction led to the linearization of dependences of signal vs. cobalt percentage, at least up to the highest studied value of 23% Co.
Control of core argon impurity profile by ECH in KSTAR L-mode plasmas
NASA Astrophysics Data System (ADS)
Hong, Joohwan; Lee, Seung Hun; Kim, Juhyung; Seon, C. R.; Lee, S. G.; Park, G. Y.; Lee, K. D.; Henderson, S. S.; Lee, H. Y.; Park, Jae Sun; Jang, Juhyeok; Jang, Siwon; Jeon, Taemin; O'Mullane, M.; Choe, Wonho
Experiments on trace argon impurity transport in L-mode discharges were performed on Korea superconducting tokamak advanced research (KSTAR) with electron cyclotron resonance heating (ECH). Ar emission was measured by soft x-ray (SXR) arrays and vacuum UV (VUV) diagnostics. A significant reduction in the core Ar emissivity was observed with core ECH. The reduction was the largest with on-axis heating and became smaller with outward heating positions. The diffusivity and convection velocity of Ar were obtained by analysis of the SXR data with the SANCO impurity transport code for the on-axis ECH and the non-ECH shots. In the on-axis ECH case, both diffusivity and convection velocity increased. Furthermore, the convection changed its direction from inward to outward in the plasma core (r/a < 0.3), resulting in a hollow profile of the total Ar density. Together with the reduction in the SXR signals, the hollow impurity profile in the core and the reversal of the convection velocity consistently confirm that ECH can reduce impurity accumulation in the core region. Neoclassical impurity transport and linear stability of micro-turbulence were calculated and discussed in relation to the possible transport mechanism.
Determination of inorganic contaminants in glue by inductively coupled argon plasma optical emission spectrometry.
Matoso, Erika; Cadore, Solange
A closed vessel method using a microwave oven was developed for the determination of As, B, Ba, Bi, Cd, Cr, Cu, Fe, Hg, Ni, Pb, Se, Sn and Sb by Inductively Coupled Argon Plasma Optical Emission Spectrometry (ICP OES). The method was applied to samples of polyvinyl acetate-based glue in water emulsions. Parameters such as wavelength, nebulization pressure and RF power were optimized and the residual acidity after the digestion process was determined. The addition of internal standards was evaluated and the accuracy of the proposed method was verified with addition and recovery experiments and also with certified reference materials, achieving good results. Using a nebulization flow rate of 0.73 L min(-1)and a RF power of 1200 W it was possible to obtain adequate values for limit of detection and limit of quantification as well as recovery values in the range of 80-106%, for all the analytes. The analysis of coloured glue samples (white, black, blue, yellow, red and green), widely used by children, showed no contamination by the elements studied. PMID:21376954
Elevated plasma factor VIII coagulant activity presenting with thrombophlebitis of the deep dorsal vein of the penis.
Shen, Heng-Li; Liu, Shih-Ping; Wang, Sho-Mon; Tsay, Woei; Hsieh, Ju-Ton
A 55-year-old man started to suffer from severe penile pain 2 days after engaging in sexual intercourse in the woman-on-top position. A fixed, 2-cm long, cord-like lesion was found on the dorsal midline of his penis which was in a partially tumescent state. Ultrasonography showed part of the deep dorsal vein was obstructed by a hyperechoic mass. Laboratory tests revealed elevated plasma factor VIII coagulant activity. The patient received thrombophlebectomy of the deep dorsal penile vein. Pathology reported venous thrombosis with eosinophilic and lymphocytic infiltration of the venous wall. At the outpatient follow up, painful thrombophlebitic veins at the previous i.v. accesses were noted on his left arm. He has received long-term warfarin control as suggested by hematologists. This patient represents the first reported case of deep dorsal penile thrombophlebitis associated with elevated plasma factor VIII coagulant activity, which is an independent risk factor of recurrent venous thromboembolism and superficial thrombophlebitis. PMID:17645617
Continuous wave cavity ring down spectroscopy measurements of velocity distribution functions of argon ions in a helicon plasma.
Chakraborty Thakur, Saikat; McCarren, Dustin; Carr, Jerry; Scime, Earl E
We report continuous wave cavity ring down spectroscopy (CW-CRDS) measurements of ion velocity distribution functions (VDFs) in low pressure argon helicon plasma (magnetic field strength of 600 G, T(e) ? 4 eV and n ? 5 × 10(11) cm(-3)). Laser induced fluorescence (LIF) is routinely used to measure VDFs of argon ions, argon neutrals, helium neutrals, and xenon ions in helicon sources. Here, we describe a CW-CRDS diagnostic based on a narrow line width, tunable diode laser as an alternative technique to measure VDFs in similar regimes but where LIF is inapplicable. Being an ultra-sensitive, cavity enhanced absorption spectroscopic technique; CW-CRDS can also provide a direct quantitative measurement of the absolute metastable state density. The proof of principle CW-CRDS measurements presented here are of the Doppler broadened absorption spectrum of Ar II at 668.6138 nm. Extrapolating from these initial measurements, it is expected that this diagnostic is suitable for neutrals and ions in plasmas ranging in density from 1 × 10(9) cm(-3) to 1 × 10(13) cm(-3) and target species temperatures less than 20 eV. PMID:22380092
Characterization of an inductively coupled nitrogen-argon plasma by Langmuir probe combined with optical emission spectroscopy
Song, M. A.; Lee, Y. W.; Chung, T. H. [Department of Physics, Dong-A University, Busan 604-714 (Korea, Republic of)
The properties of low-pressure inductively coupled nitrogen-argon plasmas were investigated by using a Langmuir probe combined with optical emission spectroscopy (OES) under the conditions of pressures in the range of 1-30 mTorr and applied rf powers of 200-600 W. In the experiments, the argon was introduced as an actinometer and as an adding gas. The effect of the argon content in the gas mixture was examined in the range of 5%-80%. The electron energy probability function (EEPF), the electron density, and the electron temperature were obtained by using an rf-compensated Langmuir probe. The dissociation fractions were obtained from the OES actinometry. The electron temperature was also obtained by OES corona model and compared with that measured by the probe. The second positive and first negative systems of spectral bands from nitrogen molecules were analyzed to estimate the vibrational and rotational temperatures. The effects of the control parameters on the plasma parameters and dissociation fraction were investigated. While the calculated nitrogen atom density increased with power, it exhibited a maximum value near the Ar content of 30%.
Surface roughening of silicon, thermal silicon dioxide, and low-k dielectric coral films in argon plasma
Yin Yunpeng; Sawin, Herbert H. [Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
The surface roughness evolutions of single crystal silicon, thermal silicon dioxide (SiO{sub 2}), and low dielectric constant film coral in argon plasma have been measured by atomic force microscopy as a function of ion bombardment energy, ion impingement angle, and etching time in an inductively coupled plasma beam chamber, in which the plasma chemistry, ion energy, ion flux, and ion incident angle can be adjusted independently. The sputtering yield (or etching rate) scales linearly with the square root of ion energy at normal impingement angle; additionally, the angular dependence of the etching yield of all films in argon plasma followed the typical sputtering yield curve, with a maximum around 60 deg. -70 deg. off-normal angle. All films stayed smooth after etching at normal angle but typically became rougher at grazing angles. In particular, at grazing angles the rms roughness level of all films increased if more material was removed; additionally, the striation structure formed at grazing angles can be either parallel or transverse to the beam impingement direction, which depends on the off-normal angle. More interestingly, the sputtering caused roughness evolution at different off-normal angles can be qualitatively explained by the corresponding angular dependent etching yield curve. In addition, the roughening at grazing angles is a strong function of the type of surface; specifically, coral suffers greater roughening compared to thermal silicon dioxide.
A method to measure electric field strengths in an argon glow discharge plasma using laser spectroscopy
Jung-Bae Kim; Kiyonori Kawamura; Young Wook Choi; Mark D. Bowden; Katsunori Muraoka; Volkmar Helbig
A method for electric field measurement based on laser spectroscopy of argon atoms has been developed and calibrated. Measurements were made using both laser optogalvanic spectroscopy and laser-induced fluorescence spectroscopy. Measurements using several different transitions in argon were carried out, and it was found that the 4s?7f and 4s?8f transitions were the most suitable for measurements in the sheath region
A study of the quantity of some stable and labile coagulation factors in fresh-frozen plasma produced from whole blood stored for 24 hours in Iran
Naghadeh, Hossin Timori; Roudkenar, Mehryar Habibi
Background The aim of this study was to assess whether the quantities of some coagulation factors in fresh-frozen plasma (FFP) produced from whole blood stored at 4°C for 24 h are adequate for their intended purpose. Materials and methods The amounts of some coagulation factors (fibrinogen, FV, FVII, FVIII, FX and FXI) in FFP separated from whole blood after storage at 4°C for 24 h were compared with the amounts of the corresponding coagulation factors in FFP separated from whole blood within 8 h of donation. Results In 98% of the FFP units prepared after 24 h of storage, the levels of fibrinogen, FV, FVII, FX and FXI were greater than 0.5 IU/mL. The concentration of FVIII in the 24 h plasma units was 82% of that found in the FFP units prepared within 8 h of blood collection. In FFP, FVIII, FVII and FX were reduced by 38%, 8% and 3%, respectively, but FV, FXI and fibrinogen were not reduced. Conclusion These data suggest that there is good retention of coagulation factor activity in plasma produced from whole blood stored at 4ºC for 24 h and that such plasma would be an acceptable product for most patients requiring FFP. PMID:19290079
Process Study of Silicon Carbide Coatings Deposited on Steel by Plasma-Assisted Chemical Vapor Deposition from Tetramethylsilane-Argon Gas System
Wei Zhang; Marc Lelogeais; Michel Ducarroir
Silicon carbide coatings were prepared in an RF plasma-assisted chemical vapor deposition (CVD) device from the tetramethylsilane-argon gas system. The present paper is devoted to investigation of the plasma process and determination of the deposition rate with the experimental parameters. By employing the general convective diffusion equation, we obtain a simple analytical expression of the deposition rate. Calculated results are
Kinetic modeling of evolution of 3?+?1:Resonance enhanced multiphoton ionization plasma in argon at low pressures
Tholeti, Siva Sashank; Alexeenko, Alina A., E-mail: firstname.lastname@example.com [School of Aeronautics and Astronautics, Purdue University, West Lafayette, Indiana 47907 (United States); Shneider, Mikhail N. [Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States)
We present numerical kinetic modeling of generation and evolution of the plasma produced as a result of resonance enhanced multiphoton ionization (REMPI) in Argon gas. The particle-in-cell/Monte Carlo collision (PIC/MCC) simulations capture non-equilibrium effects in REMPI plasma expansion by considering the major collisional processes at the microscopic level: elastic scattering, electron impact ionization, ion charge exchange, and recombination and quenching for metastable excited atoms. The conditions in one-dimensional (1D) and two-dimensional (2D) formulations correspond to known experiments in Argon at a pressure of 5?Torr. The 1D PIC/MCC calculations are compared with the published results of local drift-diffusion model, obtained for the same conditions. It is shown that the PIC/MCC and diffusion-drift models are in qualitative and in reasonable quantitative agreement during the ambipolar expansion stage, whereas significant non-equilibrium exists during the first few 10?s of nanoseconds. 2D effects are important in the REMPI plasma expansion. The 2D PIC/MCC calculations produce significantly lower peak electron densities as compared to 1D and show a better agreement with experimentally measured microwave radiation scattering.
Observation of dielectronic satellites in the K -spectrum of argon ions in plasma produced by femtosecond laser pulses
A. I. Magunov; A. Ya. Faenov; I. Yu. Skobelev; T. A. Pikuz; E. Biémont; P. Quinet; F. Blasco; C. Bonte; F. Dorchies; T. Caillaud; F. Salin; C. Stenz
The satellite structure of 1s2p\\u000a 1,3\\u000a P\\u000a 1-1s\\u000a 21\\u000a S\\u000a 0 lines of the He-like argon ion in plasma produced by a 45-fs laser pulse in a gas-jet cluster target is measured with a high\\u000a spectral resolution. Radiation transitions 2p ? 1s from autoionizing states (AISs) are detected for ions ranging from Li-like to F-like. The spectrum observed is theoretically
Urinary nickel: measurement of exposure by inductively coupled plasma argon emission spectrometry.
Koizumi, Chisato; Usuda, Kan; Hayashi, Satsuki; Dote, Tomotaro; Kono, Koichi
Nickel is a rare earth metal and is widely used in modern industry. Its overexposure in human beings can provoke significant effects including lung, cardiovascular and kidney diseases. As an index of occupational exposure, urine is widely used for the monitoring of nickel concentration because it is a minimally invasive method. Recent studies have used atomic absorption spectrometry to measure nickel concentration. In this study, we introduced novel inductively coupled plasma argon emission spectrometry (ICPAES) which enables us to measure multiple elements simultaneously with smaller volume and with lower detection limits compared to conventional atomic absorption emission spectrometry, and we established the new measuring method by determining the appropriate wavelengths for nickel concentration. Furthermore, using the established new measuring method, we investigated the correlation between a single oral administration of nickel and urine elimination in rats. As a result, different concentrations of nickel standard solutions were measured by ICPAES, and among five specific wavelengths of nickel, 221.647 and 231.604 nm were chosen because they had the highest inclines of both signal to background ratio and emission intensity in simple linear regression analysis. Next, by using healthy human urine samples that had not been exposed to nickel, 231.604 nm was determined to be the most appropriate wavelength because it did not present abnormal intensity due to obstacle wavelength. Male Wistar rats received an oral administration of nickel ranging from 0.025 to 250 mg/kg, which is equivalent to 0.0015 - 15% of LD50, and during the following 24 h, urine samples were collected and the nickel concentration was measured by ICPAES. With a single oral administration of nickel, there was an increase in urine nickel concentration in a dose-dependent manner and the appropriate equation was developed. Acute renal failure was not observed in this dosage of oral nickel administration by analysing NAG, beta2-microglobulin, urine albumin and urine protein. It was concluded that the obtained nickel reference values using ICPAES would be useful for the early diagnosis of nickel intoxication and in the assessment of the exposure to nickel. PMID:15941006
Low-temperature atmospheric pressure argon plasma treatment and hybrid laser-plasma ablation of barite crown and heavy flint glass.
Gerhard, Christoph; Roux, Sophie; Brückner, Stephan; Wieneke, Stephan; Viöl, Wolfgang
We report on atmospheric pressure argon plasma-based surface treatment and hybrid laser-plasma ablation of barite crown glass N-BaK4 and heavy flint glass SF5. By pure plasma treatment, a significant surface smoothing, as well as an increase in both the surface energy and the strength of the investigated glass surfaces, was achieved. It was shown that for both glasses, hybrid laser plasma ablation allows an increase in the ablation depth by a factor of 2.1 with respect to pure laser ablation. The ablated volume was increased by an averaged factor of 1.5 for N-BaK4 and 3.7 for SF5. PMID:22695664
Diffusion of Si atoms and thin film deposition in a silane-argon plasma
K. Tachibana; H. Tadokoro; H. Harima; Y. Urano
Time dependences of the Si atom density in a pulsed RF discharge in a mixture of 5% silane and 95% argon have been investigated by absorption spectroscopy. Decay of the Si atom density in afterglow was exponential in a low power and low flow rate limit. The time constant of the decay was proportional to the gas pressure in the
Determination of dissolved boron in fresh, estuarine, and geothermal waters by d.c. argon-plasma emission spectrometry
Ball, J.W.; Thompson, J.M.; Jenne, E.A.
A d.c. argon-plasma emission spectrometer is used to determine dissolved boron in natural (fresh and estuarine) water samples. Concentrations ranged from 0.02 to 250 mg l-1. The emission-concentration function is linear from 0.02 to 1000 mg l-1. Achievement of a relative standard deviation of ??? 3% requires frequent restandardization to offset sensitivity changes. Dilution may be necessary to overcome high and variable electron density caused by differences in alkali-metal content and to avoid quenching of the plasma by high solute concentrations of sodium and other easily ionized elements. The proposed method was tested against a reference method and found to be more sensitive, equally or more precise and accurate, less subject to interferences, with a wider linear analytical range than the carmine method. Analyses of standard reference samples yielded results in all cases within one standard deviation of the means. ?? 1978.
Absolute measurements of the continuum radiation to determine the electron density in a microwave-induced argon plasma
NASA Astrophysics Data System (ADS)
Iordanova, E.; de Vries, N.; Guillemier, M.; van der Mullen, J. J. A. M.
A method for the determination of the electron density (ne) using the continuum radiation is presented. The radiation is calibrated with a standard tungsten ribbon lamp and thus expressed in absolute units. This method is applied to a microwave-induced argon plasma, created by a surfatron (2.45 GHz), for which the standard settings are: wavelength region at 648 nm, power of 60 W, pressure of 15 mbar, gas flow of 70 sccm and axial distance from the launcher of 3 cm. Due to the low degree of ionization, the influence of electron-ion interactions can be neglected; the radiation is predominantly generated by free-free interactions between electrons and atoms. The method provides the electron density values in the order of 1019 m-3 for different plasma settings. It is observed that the measured ne follows the well-known trends—it decreases in the direction of the propagating surface wave and increases with power.
Interferometric investigation of the influence of argon buffer gas on the characteristics of laser-induced aluminum plasmas.
Oh, Seong Y; Singh, Jagdish P; Lim, Changhwan
An interferometric analysis was performed to investigate the influence of argon (Ar) buffer gas on the characteristics of laser-induced aluminum (Al) plasma at atmospheric pressure. The plasma was produced by focusing a Q-switched Nd:YAG laser pulse (?=1064??nm, pulse duration ?5??ns, E=6.0??mJ) onto an Al target. The interference patterns were constructed using a Nomarski interferometer incorporated with a frequency-doubled, Q-switched Nd:YAG laser (?=532??nm, pulse duration ?10??ns) that generates an interferometric probe beam. The interferometric measurements were carried out as a function of the elapsed time after the onset of breakdown under the conditions of open air and an Ar gas jet flow (5??l/min). With the injection of an Ar buffer gas jet in the ablation process, an increase in electron density and a preferential axial plasma expansion of the plasma plume were observed during the early stages of plasma formation as a consequence of increased inverse-Bremsstrahlung (IB) absorption efficiency. PMID:24921120
Low levels of plasma protein S, protein C and coagulation factor XII during early pregnancy and adverse pregnancy outcome.
Ebina, Y; Ieko, M; Naito, S; Kobashi, G; Deguchi, M; Minakami, H; Atsumi, T; Yamada, H
It was the study objective to evaluate whether low levels of plasma protein S (PS) activity, free PS, protein C (PC) activity and coagulation factor XII (FXII) during early pregnancy are related to adverse pregnancy outcomes. Peripheral blood samples were obtained at 8-14 gestational weeks (GW) from a consecutive series of 1,220 women. The levels of plasma PS activity, free PS, PC activity, and FXII were measured. Cut-off values were defined as 1st, 5th, and 10th percentiles of values obtained from 933 women whose pregnancies ended in normal deliveries without complications. PS activity of 10th percentile yielded risks of pregnancy-induced hypertension (PIH) and severe PIH, while free PS level of 5th percentile yielded a risk of pre-eclampsia. FXII level of 1st percentile yielded a risk of premature delivery (PD) at 34 GW. None was associated with PD at 37 GW, fetal growth restriction or fetal loss. A multivariate analysis demonstrated that PS activity of 10th percentile (odds ratio 5.9, 95?% confidence interval 1.7-18.1) and body mass index (BMI) ??25 kg/m² (4.3, 1.1-13.3) were independent risk factors for severe PIH. Similarly, free PS level of 5th percentile (4.4, 1.0-14.3) and BMI ??25 kg/m² (4.0, 1.3-10.9) were independent risk factors for pre-eclampsia. In conclusion, women with low levels of plasma PS activity and free PS during early pregnancy might have increased risks of PIH, severe PIH or pre-eclampsia. Women with low FXII level might have an increased risk of PD at 34 GW. PMID:25879167
Investigations of laser-induced plasma in argon by Thomson scattering
A. Mendys; K. Dzier??ga; M. Grabiec; S. Pellerin; B. Pokrzywka; G. Travaillé; B. Bousquet
The Thomson scattering method was applied to quantify the electron number density and temperature of a laser spark formed in argon. The laser spark was generated by focusing a 15mJ beam from the second harmonic (?L=532nm) of a nanosecond Nd:YAG laser with an 80mm focal length lens. Images of the spark emission were obtained for times between 1ns and 20?s
J. R. Norris
We consider a stochastic particle model for coagulating particles, whose free motion\\u000ais Brownian, with diffusivity given by Einstein's law. We present in outline a derivation from this\\u000amodel of a spatially inhomogeneous version of Smoluchowski's coagulation equation. Some analytic\\u000aresults on existence, uniqueness and mass conservation for the limit equation are also presented.
Evaluation of bone response to synthetic bone grafting material treated with argon-based atmospheric pressure plasma.
Beutel, Bryan G; Danna, Natalie R; Gangolli, Riddhi; Granato, Rodrigo; Manne, Lakshmiprada; Tovar, Nick; Coelho, Paulo G
Bone graft materials are utilized to stimulate healing of bone defects or enhance osseointegration of implants. In order to augment these capabilities, various surface modification techniques, including atmospheric pressure plasma (APP) surface treatment, have been developed. This in vivo study sought to assess the effect of APP surface treatment on degradation and osseointegration of Synthograft™, a beta-tricalcium phosphate (?-TCP) synthetic bone graft. The experimental (APP-treated) grafts were subjected to APP treatment with argon for a period of 60s. Physicochemical characterization was performed by environmental scanning electron microscopy, surface energy (SE), and x-ray photoelectron spectroscopy analyses both before and after APP treatment. Two APP-treated and two untreated grafts were surgically implanted into four critical-size calvarial defects in each of ten New Zealand white rabbits. The defect samples were explanted after four weeks, underwent histological analysis, and the percentages of bone, soft tissue, and remaining graft material were quantified by image thresholding. Material characterization showed no differences in particle surface morphology and that the APP-treated group presented significantly higher SE along with higher amounts of the base material chemical elements on it surface. Review of defect composition showed that APP treatment did not increase bone formation or reduce the amount of soft tissue filling the defect when compared to untreated material. Histologic cross-sections demonstrated osteoblastic cell lines, osteoid deposition, and neovascularization in both groups. Ultimately, argon-based APP treatment did not enhance the osseointegration or degradation of the ?-TCP graft. Future investigations should evaluate the utility of gases other than argon to enhance osseointegration through APP treatment. PMID:25491854
Direct solid atomic emission spectrometric analysis of metal samples by an argon microwave plasma torch coupled to spark ablation
NASA Astrophysics Data System (ADS)
Engel, U.; Kehden, A.; Voges, E.; Broekaert, J. A. C.
Spark ablation has been combined to microwave plasma torch atomic emission spectrometry for the direct analysis of compact metallic samples. The material is ablated by a medium voltage spark (450 V, 370 Hz) in a point-to-plane configuration and swept into a 100-W, 2.45-GHz argon microwave discharge. The microwave plasma is observed end-on and the radiation analysed with a polychromator. The detection limits for Fe, Ni, Pb and Sn in brass, Cr, Cu, Ni, Mn, Mo, Si and V in steel and Cu, Fe, Mg, Mn, Si and Zn in aluminium with the microwave plasma torch in the case of measurements with a polychromator are in the ?g/g range and by a factor of up to 20 higher than those obtained with spark ablation coupled to inductively coupled plasma atomic emission spectrometry using a high resolution sequential spectrometer. The stability of the emission signal depends on the element studied and relative standard deviations usually are between 0.5 and 3.5%. In the case of low-alloy steels, the linearity and the precision of the calibration could be improved by internal standardisation. Several elements (Cr, Cu, Ni, Si and V) could be determined in a steel sample (BAS SS 410/1) with high accuracy and precision.
Determination of rare earth elements in geological materials by inductively coupled argon plasma/atomic emission spectrometry
Crock, J.G.; Lichte, F.E.
Inductively coupled argon plasma/optical emission spectrometery (ICAP/OES) is useful as a simultaneous, multielement analytical technique for the determination of trace elements in geological materials. A method for the determination of trace-level rare earth elements (REE) in geological materials using an ICAP 63-channel emission spectrometer is described. Separation and preconcentration of the REE and yttrium from a sample digest are achieved by a nitric acid gradient cation exchange and hydrochloric acid anion exchange. Precision of 1-4% relative standard deviation and comparable accuracy are demonstrated by the triplicate analysis of three splits of BCR-1 and BHVO-1. Analyses of other geological materials including coals, soils, and rocks show comparable precision and accuracy.
The antibacterial activity of a microwave argon plasma jet at atmospheric pressure relies mainly on UV-C radiations
NASA Astrophysics Data System (ADS)
Judée, F.; Wattieaux, G.; Merbahi, N.; Mansour, M.; Castanié-Cornet, M. P.
The main bactericidal sources produced by a microwave induced cold argon plasma jet in open air are identified and their relative proportion in the biocide efficiency of the jet is assessed on planktonic Gram-negative bacteria (wild-type strains and deletion mutants of Escherichia coli) diluted in water. In these conditions ultraviolet light (UV) most probably in the UV-C region of the electromagnetic spectrum, is responsible for 86.7 ± 3.2% of the observed bactericidal efficiency of the jet whereas hydrogen peroxide represents 9.9 ± 5.5% of it. The exposition level of the bacteria to UV-C radiations is estimated at 20 mJ cm-2 using a specific photodiode and the influence of the initial bacteria concentration on the apparent antibacterial efficiency of the jet is highlighted.
Double layer-like structures in the core of an argon helicon plasma source with uniform magnetic fields
Umair Siddiqui, M., E-mail: email@example.com; Hershkowitz, Noah [Department of Engineering Physics, University of Wisconsin—Madison, Madison, Wisconsin 53706 (United States)] [Department of Engineering Physics, University of Wisconsin—Madison, Madison, Wisconsin 53706 (United States)
A hot (T{sub e} ? 10?eV) electron population is observed in the core of a 3 mTorr argon helicon plasma source at 500?W RF power and 900 G uniform axial magnetic field strength, 12?cm from the edge of the helicon antenna. A double layer-like structure consisting of a localized axial electric field of approximately 8?V/cm over 1–2?cm is observed adjacent to the hot electron population. The potential step generated by the electric field is shown to be large enough to trap the hot electrons. To our knowledge this is the first observation of these structures in the core of a helicon discharge.
Effects of matching network on the hysteresis during E and H mode transitions in argon inductively coupled plasma
Gao Fei; Zhao Shuxia; Li Xiaosong; Wang Younian [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)
An experimental investigation of the hysteresis during the E (capacitive coupling) and H mode (inductive coupling) transitions at various matching situation in argon inductively coupled plasma is reported. At high pressure, the results show two hysteresis loops involved the plasma density, applied power, and forward power, as well as the electrical parameters in the discharge circuit, when the series capacitance is cycled. The measured electron density versus applied power shows that the hysteresis loop shrinks with the decrease of the matching capacitance, and the same trend is discovered on the input current, voltage, and phase angle. In addition, for the case of small capacitance, the current (or voltage) jumps to a low value when the discharge passes through the E to H mode transition regime. Contrarily, for the case of large capacitance, the current jumps to a high value while the voltage is almost constant. The evolution characteristics of the plasma and circuit parameters observed imply that the nonlinear behavior of the matching situation may be one of the determined factors for hysteresis.
One- and two-dimensional modeling of argon K-shell emission from gas-puff Z-pinch plasmas
Thornhill, J. W.; Chong, Y. K.; Apruzese, J. P.; Davis, J.; Clark, R. W.; Giuliani, J. L. Jr.; Terry, R. E.; Velikovich, A. L.; Commisso, R. J.; Whitney, K. G.; Frese, M. H.; Frese, S. D.; Levine, J. S.; Qi, N.; Sze, H.; Failor, B. H.; Banister, J. W.; Coleman, P. L.; Coverdale, C. A.; Jones, B. [Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375 (United States); Berkeley Scholars, Beltsville, Maryland 20705 (United States); NumerEx, Albuquerque, New Mexico 87106 (United States); L-3 Communications/Pulse Sciences, San Leandro, California 94577 (United States); Alameda Applied Sciences, San Leandro, California 94577 (United States); Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); National Nuclear Security Administration, Washington, D.C. 20585 (United States)] (and others)
In this paper, a theoretical model is described and demonstrated that serves as a useful tool for understanding K-shell radiating Z-pinch plasma behavior. Such understanding requires a self-consistent solution to the complete nonlocal thermodynamic equilibrium kinetics and radiation transport in order to realistically model opacity effects and the high-temperature state of the plasma. For this purpose, we have incorporated into the MACH2 two-dimensional magnetohydrodynamic (MHD) code [R. E. Peterkin et al., J. Comput. Phys. 140, 148 (1998)] an equation of state, called the tabular collisional radiative equilibrium (TCRE) model [J. W. Thornhill et al., Phys. Plasmas 8, 3480 (2001)], that provides reasonable approximations to the plasma's opacity state. MACH2 with TCRE is applied toward analyzing the multidimensional implosion behavior that occurred in Decade Quad (DQ) [D. Price et al., Proceedings of the 12th IEEE Pulsed Power Conference, Monterey, CA, edited by C. Stallings and H. Kirbie (IEEE, New York, 1999), p. 489] argon gas puff experiments that employed a 12 cm diameter nozzle with and without a central gas jet on axis. Typical peak drive currents and implosion times in these experiments were {approx}6 MA and {approx}230 ns. By using Planar Laser Induced Fluorescence measured initial density profiles as input to the calculations, the effect these profiles have on the ability of the pinch to efficiently produce K-shell emission can be analyzed with this combined radiation-MHD model. The calculated results are in agreement with the experimental result that the DQ central-jet configuration is superior to the no-central-jet experiment in terms of producing more K-shell emission. These theoretical results support the contention that the improved operation of the central-jet nozzle is due to the better suppression of instabilities and the higher-density K-shell radiating conditions that the central-jet configuration promotes. When we applied the model toward projecting argon K-shell yield behavior for Sandia National Laboratories' ZR machine ({approx}25 MA peak drive currents, {approx}100 ns implosion times) [D. McDaniel et al., Proceedings of the 5th International Conference on Dense Z-Pinches, Albuquerque, NM, 2002, edited by J. Davis, C. Deeney, and N. R. Pereira (American Institute of Physics, New York, 2002), Vol. 651, p. 23] for experiments that utilize the 12 cm diameter central-jet nozzle configuration, it predicts over 1 MJ of K-shell emission is attainable.
Coaxial Microwave Plasmas in Argon: Radial Contraction, Self-Organization and more Exotic Phenomena
Carbone, E A D; van Veldhuizen, E M; Schrader, A; Nijdam, S; Kroesen, G M W
A coaxial microwave plasma setup was designed for investigation by optical and laser diagnostics. The plasma is sustained by two microwave power sources located at both ends of a coaxial line. This allows generating an axially homogeneous glow discharge at low pressure. For increasing pressures, this glow-like mode is found to be unstable and various self-organized patterns are observed including finger-like structures which can be sustained after the visible end of the plasma column.
Electron properties and air mixing in radio frequency driven argon plasma jets at atmospheric pressure
Gessel, Bram van; Bruggeman, Peter [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands)] [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands); Brandenburg, Ronny [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands) [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands); Leibniz Institute for Plasma Science and Technology (INP Greifswald), Felix-Hausdorff-Str. 2, D-17489 Greifswald (Germany)
A time modulated radio frequency (RF) plasma jet operated with an Ar mixture is investigated by measuring the electron density and electron temperature using Thomson scattering. The measurements have been performed spatially resolved for two different electrode configurations and as a function of the plasma dissipated power and air concentration admixed to the Ar. Time resolved measurements of electron densities and temperatures during the RF cycle and after plasma power switch-off are presented. Furthermore, the influence of the plasma on the air entrainment into the effluent is studied using Raman scattering.
Numerical Simulation of Flow in the Chamber of the Water-Argon Plasma Generator
NASA Astrophysics Data System (ADS)
Hlbo?an, Peter; Varchola, Michal; Knížat, Branislav; Mlkvik, Marek; Olšiak, Róbert
Spectral blueshifts in laser light scattered from argon-gas-cluster plasmas
Singhal, H.; Arora, V.; Naik, P.A.; Gupta, P.D. [Laser Plasma Division, Centre for Advanced Technology, Indore 452013 (India)
An experimental study is presented on scattering of laser light from argon gas clusters irradiated by multipicosecond Nd:glass laser pulses at moderate intensity of 10{sup 15} W/cm{sup 2}. Space-resolved side-scattered laser light has a predominantly blueshifted and broadened spectrum (up to {approx}8 nm). The scattered signal intensity and average blueshift exhibit a marked dependence on the backing pressure of the gas. The results are explained by self-phase modulation of the laser radiation due to changing polarizability as the heated clusters pass through resonance at 3 times the critical density during which intense absorption and scattering occurs. The observed blueshift may be useful in diagnostics of this important phase of laser-cluster interactions.
Chemical and Mechanical Analysis of PCB Surface Treated by Argon Plasma to Enhance Interfacial Adhesion
Dong Kil Shin; Hyo Sug Lee; Jay Im
Plasma treatment of printed circuit board (PCB) is a common step in the electronic packaging processes in order to modify the surface and enhance its adhesion to molding compound. In this paper, PCB surface modifications resulting from plasma treatment were investigated by chemical and mechanical analysis methods. The PCB substrate in consideration was for multichip package, consisting of a core
Shock-wave propagation in the plasma of a transverse glow discharge in argon
I. V. Basargin; G. I. Mishin
Shock waves traveling perpendicularly to a glow discharge in an Ar plasma and Ar with no plasma were observed experimentally to examine the dissipation of shock wave energy. A piezoelectric gage attached to a quartz rod furnished the pressure pulse data by which the shock velocities could be monitored at two points in the ambient medium. The shock wave propagated
A sequence variation scan of the coagulation factor VIII (FVIII) structural gene and associations with plasma FVIII activity levels
Viel, Kevin R.; Machiah, Deepa K.; Warren, Diane M.; Khachidze, Manana; Buil, Alfonso; Fernstrom, Karl; Souto, Juan C.; Peralta, Juan M.; Smith, Todd; Blangero, John; Porter, Sandra; Warren, Stephen T.; Fontcuberta, Jordi; Soria, Jose M.; Dana Flanders, W.; Almasy, Laura
Plasma factor VIII coagulant activity (FVIII:C) level is a highly heritable quantitative trait that is strongly correlated with thrombosis risk. Polymorphisms within only 1 gene, the ABO blood-group locus, have been unequivocally demonstrated to contribute to the broad population variability observed for this trait. Because less than 2.5% of the structural FVIII gene (F8) has been examined previously, we resequenced all known functional regions in 222 potentially distinct alleles from 137 unrelated nonhemophilic individuals representing 7 racial groups. Eighteen of the 47 variants identified, including 17 single-nucleotide polymorphisms (SNPs), were previously unknown. As the degree of linkage disequilibrium across F8 was weak overall, we used measured-genotype association analysis to evaluate the influence of each polymorphism on the FVIII:C levels in 398 subjects from 21 pedigrees known as the Genetic Analysis of Idiopathic Thrombophilia project (GAIT). Our results suggested that 92714C>G, a nonsynonymous SNP encoding the B-domain substitution D1241E, was significantly associated with FVIII:C level. After accounting for important covariates, including age and ABO genotype, the association persisted with each C-allele additively increasing the FVIII:C level by 14.3 IU dL?1 (P = .016). Nevertheless, because the alleles of 56010G>A, a SNP within the 3? splice junction of intron 7, are strongly associated with 92714C>G in GAIT, additional studies are required to determine whether D1241E is itself a functional variant. PMID:17209060
Comparative study on contribution of charge-transfer collision to excitations of iron ion between argon radio-frequency inductively-coupled plasma and nitrogen microwave induced plasma
NASA Astrophysics Data System (ADS)
Satoh, Kozue; Wagatsuma, Kazuaki
This paper describes an ionization/excitation phenomenon of singly-ionized iron occurring in an Okamoto-cavity microwave induced plasma (MIP) as well as an argon radio-frequency inductively-coupled plasma (ICP), by comparing the Boltzmann distribution among iron ionic lines (Fe II) having a wide range of the excitation energy from 4.76 to 9.01 eV. It indicated in both the plasmas that plots of Fe II lines having lower excitation energies (4.76 to 5.88 eV) were fitted on each linear relationship, implying that their excitations were caused by a dominant thermal process such as collision with energetic electron. However, Fe II lines having higher excitation energies (more than 7.55 eV) had a different behavior from each other. In the ICP, Boltzmann plots of Fe II lines assigned to the higher excited levels also followed the normal Boltzmann relationship among the low-lying excited levels, even including a deviation from it in particular excited levels having an excitation energy of ca. 7.8 eV. This deviation can be attributed to a charge-transfer collision with argon ion, which results in the overpopulation of these excited levels, but the contribution is small. On the other hand, the distribution of the high-lying excited levels was non-thermal in the Okamoto-cavity MIP, which did not follow the normal Boltzmann relationship among the low-lying excited levels. A probable reason for the non-thermal characteristics in the MIP is that a charge-transfer collision with nitrogen molecule ion having many vibrational/rotational levels could work for populating the 3d64p (3d54s4p) excited levels of iron ion broadly over an energy range of 7.6-9.0 eV, while collisional excitation by energetic electron would occur insufficiently to excite these high-energy levels.
Effect of argon and hydrogen on deposition of silicon from tetrochlrosilane in cold plasmas
NASA Technical Reports Server (NTRS)
Manory, R. R.; d.
The roles of Ar and H2 on the decomposition of SiCl4 in cold plasma were investigated by Langmuir probes and mass spectrometry. Decomposition of the reactant by Ar only has been found to be very slow. In presence of H2 in the plasma SiCl4 is decomposed by fast radical-molecule reactions which are further enhanced by Ar due to additional ion-molecule reactions in which more H radicals are produced. A model for the plasma-surface interactions during deposition of mu-Si in the Ar + H2 + SiCl4 system is presented.
Synthesis of ultrafine ceramic and metallic powders in a thermal argon rf plasma
Vogt, G.J.; Vigil, R.S.; Newkirk, L.R.; Trkula, M.
Ultrafine powders of SiC, Si/sub 3/N/sub 4/, Ni, and Al/sub 2/O/sub 3/ have been prepared in a rf-plasma reactor, utilizing an induction plasma tube designed at Los Alamos. The primary particle size of the ceramic powders ranges from 5 to 50 nm. Silicon carbide and alumina are ultrapure crystalline powders, while silicon nitride is amorphous for surface areas greater than 100 m/sup 2//g. Plasma nickel powder will sinter to full density at 1073 K.
Production of high quality syngas from argon/water plasma gasification of biomass and waste.
Hlina, M; Hrabovsky, M; Kavka, T; Konrad, M
Extremely hot thermal plasma was used for the gasification of biomass (spruce sawdust, wood pellets) and waste (waste plastics, pyrolysis oil). The plasma was produced by a plasma torch with DC electric arc using unique hybrid stabilization. The torch input power of 100-110 kW and the mass flow rate of the gasified materials of tens kg/h was set up during experiments. Produced synthetic gas featured very high content of hydrogen and carbon monoxide (together approximately 90%) that is in a good agreement with theory. High quality of the produced gas is given by extreme parameters of used plasma--composition, very high temperature and low mass flow rate. PMID:24148259
Numerical simulation study on fluid dynamics of plasma window using argon
Huang, S.; Zhu, K.; Shi, B. L.; Lu, Y. R. [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China)] [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Hershcovitch, A. [Brookhaven National Laboratory, New York 11973-5000 (United States)] [Brookhaven National Laboratory, New York 11973-5000 (United States); Yang, L.; Zhang, X. Y.; Wei, G. D. [Institute of Modern Physics, Chinese Academy of Science, Lanzhou 730000 (China)] [Institute of Modern Physics, Chinese Academy of Science, Lanzhou 730000 (China)
In this paper, a numerical 2D FLUENT-based magneto-hydrodynamic model has been developed to investigate the arc and flow field of plasma window, which is used as a windowless vacuum sealing device. The gas inlet, arc creation-developing and plasma expansion segments are all incorporated together in the integral model. An axis-symmetry cathode structure (hollow cathode) is used in the model. Current distribution of the arc is presented and discussed. The temperature, velocity, and pressure field are presented to show the physical mechanisms for the high pressure gap within the plasma window. Flow acceleration and viscosity effect are concluded as the main reasons for the pressure drop. The result for the pressure distribution in the cylindrical tube section has a good agreement with the analytical model. The validation for the sealing ability of plasma window is verified.
Argon plasma treatment on Cu surface for Cu bonding in 3D integration and their characteristics
NASA Astrophysics Data System (ADS)
Park, Manseok; Baek, Soojung; Kim, Sungdong; Kim, Sarah Eunkyung
3D integration enhances RC delay mitigation, improves inter-die bandwidth, and has routing advantages for the next generation integrated circuit technology. To realize the advantages of 3D integration, metallic bonding between different dies or wafers is necessary. So, Cu-to-Cu metallic bonding is, without doubt, a key process needed for 3D integration. In this study, Ar plasma treatment on the Cu surface for Cu thermo-compression bonding temperature less than 400 °C was investigated. Ar plasma treatment on the Cu thin film was performed using a conventional DC sputtering technique. The effect of Cu surface modified by Ar plasma was studied for Cu-to-Cu bonding. Also, the influence of Ar plasma treatment on the Cu surface was evaluated structurally and electrically.
The Role of Spraying Parameters and Inert Gas Shrouding in Hybrid Water-Argon Plasma Spraying of Tungsten and Copper for Nuclear Fusion Applications
NASA Astrophysics Data System (ADS)
Mat?jí?ek, J.; Kavka, T.; Bertolissi, G.; Ctibor, P.; Vilémová, M.; Mušálek, R.; Nevrlá, B.
Tungsten-based coatings have potential application in the plasma-facing components in future nuclear fusion reactors. By the combination of refractory tungsten with highly thermal conducting copper, or steel as a construction material, functionally graded coatings can be easily obtained by plasma spraying, and may result in the development of a material with favorable properties. During plasma spraying of these materials in the open atmosphere, oxidation is an important issue, which could have adverse effects on their properties. Among the means to control it is the application of inert gas shrouding, which forms the subject of this study and represents a lower-cost alternative to vacuum or low-pressure plasma spraying, potentially applicable also for spraying of large surfaces or spacious components. It is a continuation of recent studies focused on the effects of various parameters of the hybrid water-argon torch on the in-flight behavior of copper and tungsten powders and the resultant coatings. In the current study, argon shrouding with various configurations of the shroud was applied. The effects of torch parameters, such as power and argon flow rate, and powder morphology were also investigated. Their influence on the particle in-flight behavior as well as the structure, composition and properties of the coatings were quantified. With the help of auxiliary calculations, the mass changes of the powder particles, associated with oxidation and evaporation, were assessed.
Attenuation of wall disturbances in an electron cyclotron resonance oxygen–argon plasma using real time control
Keville, Bernard, E-mail: firstname.lastname@example.com; Gaman, Cezar; Turner, Miles M. [National Centre for Plasma Science and Technology (NCPST), Research and Engineering Building, Dublin City University, Glasnevin, Dublin 9, Ireland and School of Physical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland); Zhang, Yang; Daniels, Stephen [National Centre for Plasma Science and Technology (NCPST), Research and Engineering Building, Dublin City University, Glasnevin, Dublin 9, Ireland and School of Electronic Engineering, Dublin City University, Glasnevin, Dublin 9 (Ireland); Holohan, Anthony M. [School of Electronic Engineering, Dublin City University, Glasnevin, Dublin 9 (Ireland)
Present practice in plasma-assisted semiconductor manufacturing specifies recipes in terms of inputs such as gas flow rates, power and pressure. However, ostensibly identical chambers running identical recipes may produce very different results. Extensive chamber matching, i.e., initial iterative, empirical tuning of the process recipe, which entails time-consuming, ex situ statistical analysis of process metrics such as etch depth, uniformity, anisotropy and selectivity, is required to ensure acceptable results. Once matched, chambers are run open loop and are thus sensitive to disturbances such as actuator drift, wall seasoning and substrate loading, which may impact negatively on process reproducibility. An alternative approach, which may obviate the need for chamber matching and reduce the sensitivity of process metrics to exogenous disturbances, would be to specify a recipe in terms of quantities such as active species densities, and to regulate these in real time by adjusting the inputs with a suitable control algorithm. In this work, real time control of an electron cyclotron resonance O{sub 2}/Ar plasma used for photoresist ashing has been implemented. The design of elementary, model-based algorithms for the control of the argon 750 and oxygen 844 line intensities measured by optical emission spectroscopy is described. Fluorination of the chamber walls by means of an SF{sub 6} plasma prior to ashing inhibits wall recombination of oxygen radicals resulting in an approximately 20% increase in ash rate in the open loop case. However, closed loop control almost completely attenuates the effect of fluorination, thus demonstrating the efficacy of the control algorithms in ensuring a reproducible ash rate in the face of a wall disturbance.
Modeling Argon Plasma Excimer Characteristics near a Dielectric Surface in Miniaturized Volumes
NASA Astrophysics Data System (ADS)
Farahat, Ashraf; Ramadan, Emad
We computationally model plasma -neutral gas dynamics in a miniaturized microthruster encloses Ar and contains a dielectric material sandwiched between two metal plates using a two dimensional plasma model. Spatial and temporal plasma properties are investigated by solving the Poisson equation with the conservation equations of charged and excited neutral plasma species. We find the microthruster properties to depend on small changes in the secondary electron emission coefficient that could result from dielectric erosion and aging. The changes also affect the electrohydrodynamic force produced when we use the microthruster to generate thrust for small spacecrafts. The electrohydrodynamic force is calculated and found to be significant in the sheath area near the dielectric layer and is found to affect gas flow dynamics including the Ar excimer formation and density. The plasma-neutral gas momentum exchange is significant in affecting gas flow dynamics and in the formation of excimer species in addition to affecting the UV and visible emission characteristics of the device. The authors would like to acknowledge the support provided by the Deanship of Scientific Research (DSR) at the King Fahd University of Petroleum & Minerals (KFUPM) for funding this work through Project No. IN111026.
The effect of helium impurity addition on current sheath speed in argon-operated plasma focus using a tridimensional magnetic probe
NASA Astrophysics Data System (ADS)
Panahi, N.; Mohammadi, M. A.; Hedyeh, S.; Rawat, R. S.; Rawat
Using the tridimensional magnetic probe, the current sheath velocity at 0.25 Torr is studied in Sahand, a Filippov-type plasma focus facility. The current sheath velocity in argon-filled plasma focus with different percentages of helium impurity at different operating voltages was studied. The highest average current sheath velocity of 12.26 +/- 1.51 cm ?s-1 at the top of the anode in the axial phase was achieved at 17 kV. Minimum average current sheath velocity is 5.24 +/- 1.18 cm ?s-1 at 12 kV with 80% argon + 20% helium as a working gas. The full width at half-maximum of peaks of the magnetic probe was found to be inversely related to the current sheath velocity, i.e. smaller at higher voltages for different impurity and decreased with increasing of impurity.
Absorption spectroscopy measurements of argon metastable and resonant atom density in atmospheric pressure Ar-He surface-wave plasmas using a low pressure lamp
NASA Astrophysics Data System (ADS)
Muñoz, J.; Margot, J.; Calzada, M. D.
The densities of metastable and resonant atom were measured in atmospheric pressure Ar-He surface-wave plasmas. Measurements were performed using an absorption spectroscopy method taking into account the Voigt profiles of the plasma lines. The density values of the argon 3P2, 3P0 (metastable atoms) and 3P1 (resonant atoms) levels measured in pure argon discharges are in good agreement with those reported in the literature. A drastic decrease of metastable and resonant densities is observed when introducing helium in amounts as low as 2%. The influence of electron density and gas temperature on the population mechanisms (direct electron excitation from the ground state and dissociative recombination) of metastable and resonant atoms is discussed using a simplified theoretical model.
Dynamics of plasma expansion and shockwave formation in femtosecond laser-ablated aluminum plumes in argon gas at atmospheric pressures
Miloshevsky, Alexander; Harilal, Sivanandan S.; Miloshevsky, Gennady, E-mail: email@example.com; Hassanein, Ahmed [Center for Materials Under Extreme Environment, and School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)] [Center for Materials Under Extreme Environment, and School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)
Plasma expansion with shockwave formation during laser ablation of materials in a background gasses is a complex process. The spatial and temporal evolution of pressure, temperature, density, and velocity fields is needed for its complete understanding. We have studied the expansion of femtosecond (fs) laser-ablated aluminum (Al) plumes in Argon (Ar) gas at 0.5 and 1 atmosphere (atm). The expansion of the plume is investigated experimentally using shadowgraphy and fast-gated imaging. The computational fluid dynamics (CFD) modeling is also carried out. The position of the shock front measured by shadowgraphy and fast-gated imaging is then compared to that obtained from the CFD modeling. The results from the three methods are found to be in good agreement, especially during the initial stage of plasma expansion. The computed time- and space-resolved fields of gas-dynamic parameters have provided valuable insights into the dynamics of plasma expansion and shockwave formation in fs-pulse ablated Al plumes in Ar gas at 0.5 and 1?atm. These results are compared to our previous data on nanosecond (ns) laser ablation of Al [S. S. Harilal et al., Phys. Plasmas 19, 083504 (2012)]. It is observed that both fs and ns plumes acquire a nearly spherical shape at the end of expansion in Ar gas at 1?atm. However, due to significantly lower pulse energy of the fs laser (5 mJ) compared to pulse energy of the ns laser (100 mJ) used in our studies, the values of pressure, temperature, mass density, and velocity are found to be smaller in the fs laser plume, and their time evolution occurs much faster on the same time scale. The oscillatory shock waves clearly visible in the ns plume are not observed in the internal region of the fs plume. These experimental and computational results provide a quantitative understanding of plasma expansion and shockwave formation in fs-pulse and ns-pulse laser ablated Al plumes in an ambient gas at atmospheric pressures.
Suppression of a plasma instability in an argon ion laser by a helium admixture
D. V. Veselov; I. E. Sakharov; S. V. Shatalin
It is shown experimentally that the higher gain of an Ar\\/sup +\\/ laser obtained at increasing electron temperatures is limited by a plasma instability. The possibility of suppressing this instability by adding a ballast gas (He) to the working volume is studied. Suppression of the instability increases the gain and the power.
Transport of argon ions in an inductively coupled high-density plasma reactor
N. Sadeghi; Grift van der M; D. Vender; G. M. W. Kroesen; F. J. de Hoog
The first direct observation of the velocity distribution of the metastable Ar{sup +}{sup *}(²Gââ) ions in the presheath of an inductively coupled plasma has been achieved by using the Doppler shifted laser induced fluorescence technique. Drift of the ions along the electric field in the presheath is observed and distribution functions of the velocity in both parallel and perpendicular directions,
Surface Modification of Epoxy Resin Based PCB Substrates using Argon and Oxygen Plasmas
B. N. Laniog; H. J. Ramos; M. Wada; M. G. Mena; R. E. Flauta
We report the effect of surface treatments of Ar and oxygen plasma on the adhesion quality of the metal-polymer interface. Here, we used three types of thin film metals of different thickness: copper (Cu) as the metal seed coat with thickness of 200 nm; and chromium (Cr) and aluminum (Al) as the film tie coats (thickness varied from 5-15 nm).
Production of Coatings from Powder Materials with the Use of a Short Argon Arc. 2. Heat Flux from the Plasma to a Macroparticle
I. P. Smyaglikov; V. D. Shimanovich; Yu. V. Khodyko
The heat flux to a metal particle in the plasma of a short argon arc of atmospheric pressure in depositing metallurgical coatings has been calculated. The limiting approximations of a continuum and free-molecular flow yield comparable results (about 6·108 W\\/m2). The radiant-flux density has been evaluated. It has been shown that the heating of macroparticles is determined mainly by the
X-ray Emission from Argon Plasma Focus Contaminated with Copper Impurities in AECS PF2 Using Five Channel Diode Spectrometer
Sh. Al-Hawat; M. Akel; C. S. Wong
In this work, the X-ray ratio method using different thicknesses of Al foil absorbers was used to study the influence of copper\\u000a impurities on the electron temperature determination of the focused plasma in AECS PF-2 with argon filling gas. Five channels\\u000a of BPX 65 PIN diodes were employed to record the X-ray pulses generated by a low energy Mather type
Solution nebulization into a low-power argon microwave-induced plasma for atomic emission spectrometry: study of synthetic ocean water
Kin C. Ng; Wei Lung. Shen
A MAK nebulizer is used to introduce liquid aerosols containing Cr, Mn, In, V, Pb, Sr, or Zr into a low-power (105-115 W), low argon flow (537 mL\\/min) microwave-induced plasma for atomic emission spectrometry. Detection limits (3sigma) in 3% nitric acid water samples are at the parts-per-billion level (62, 18, 18, 91, 139, 13, and 3945, respectively). These values compared
Effects of the electrical excitation signal parameters on the geometry of an argon-based non-thermal atmospheric pressure plasma jet.
Benabbas, Mohamed Tahar; Sahli, Salah; Benhamouda, Abdallah; Rebiai, Saida
A non-thermal atmospheric pressure argon plasma jet for medical applications has been generated using a high-voltage pulse generator and a homemade dielectric barrier discharge (DBD) reactor with a cylindrical configuration. A plasma jet of about 6 cm of length has been created in argon gas at atmospheric pressure with an applied peak to peak voltage and a frequency of 10 kV and 50 kHz, respectively. The length and the shape of the created plasma jet were found to be strongly dependent on the electrode setup and the applied voltage and the signal frequency values. The length of the plasma jet increases when the applied voltage and/or its frequency increase, while the diameter at its end is significantly reduced when the applied signal frequency increases. For an applied voltage of 10 kV, the plasma jet diameter decreases from near 5 mm for a frequency of 10 kHz to less than 1 mm at a frequency of 50 kHz. This obtained size of the plasma jet diameter is very useful when the medical treatment must be processed in a reduced space. PACS 2008: 52.50.Dg; 52.70.-m; 52.80.-s. PMID:26088991
Silicon nitride etching performance of CH2F2 plasma diluted with argon or krypton
NASA Astrophysics Data System (ADS)
Kondo, Yusuke; Ishikawa, Kenji; Hayashi, Toshio; Miyawaki, Yudai; Takeda, Keigo; Kondo, Hiroki; Sekine, Makoto; Hori, Masaru
Etching rates of silicon nitrides (SiN), SiO2, and poly-Si films for CH2F2 plasmas diluted with rare gases are presented by comparing the effects of flow rates of CH2F2 and dilution gases (Ar and Kr). The SiO2 etching rate was considered to be controlled by ion fluxes of the incident CHF2+ and CH2F+ under the conditions for the selective etching of SiO2 and SiN over poly-Si. Interestingly, the SiN etching rate was considerably affected by the dilution gas used. The SiN surface reaction was promoted by F-rich chemistry in the Ar-diluted CH2F2 plasma with a relatively high density of F atoms.
Expansion dynamics of ultrafast laser produced plasmas in the presence of ambient argon
NASA Astrophysics Data System (ADS)
Diwakar, P. K.; Harilal, S. S.; Hassanein, A.; Phillips, M. C.
We investigated the expansion dynamics of fs laser ablated brass plasma in Ar at various pressure levels ranging from 10-5 Torr to atmospheric conditions using time-resolved and spectrally resolved two-dimensional imaging. Significant changes in plume morphology were noticed at varying pressure levels which included free expansion, spherical to cylindrical geometry changes, sharpening, and confinement. The temporal evolution of excited Cu and Zn species in the plume were imaged using narrow band-pass interference filters, and their hydrodynamic expansion features were compared. 2D imaging coupled with monochromatic line selection showed velocity differences, uneven distribution, and aspect ratio differences among the plume species. Plume morphological changes were found to be significant at intermediate pressure levels (˜10 Torr) where plasma emissivity was found to be maximum. The expansion features of plume were compared with various models and found to be generally in good agreement.
Transport of argon ions in an inductively coupled high-density plasma reactor
N. Sadeghi; M. van de Grift; D. Vender; G. M. W. Kroesen; F. J. de Hoog
The first direct observation of the velocity distribution of the metastable Ar+*(2G9\\/2) ions in the presheath of an inductively coupled plasma has been achieved by using the Doppler shifted laser induced fluorescence technique. Drift of the ions along the electric field in the presheath is observed and distribution functions of the velocity in both parallel and perpendicular directions, relative to
Molecular ion formation in decaying plasmas produced in pure argon and krypton
M. Langenwalter; H. Helm
The formation of molecular ions Ar2+ and Kr2+ in decaying plasmas of the respective rare gases is studied at pressures between 0.2 and 3 Torr at room temperature. Measurements of the decay of He2+ in He are made to test the experimental technique used. The reaction rate coefficient for the process Ar+(2P3\\/2)+2 Ar?Ar2++Ar is found to be (2.35±0.2)×10?31 cm6 s?1.
Expansion Dynamics of Ultrafast Laser Produced Plasmas in the Presence of Ambient Argon
Diwakar, P. K.; Harilal, Sivanandan S.; Hassanein, A.; Phillips, Mark C.
In this paper, we report the emission features of fs laser ablated brass plasma plumes at various Ar background pressure levels ranging from vacuum to atmospheric conditions. Spectrally integrated 2D-imaging of plasma self-emission showed several interesting features at various pressure levels which consists of plume morphological changes, increase in persistence, confinement, and internal structures. Spatially resolved wavelength dispersed images of the plume were recorded for characterizing the spectral features at various pressure levels and also used for obtaining spatial distribution of Cu I and Zn I species in the plume, signal to noise ratios and fundamental parameters of the plasma; viz. temperature and density. The spatial evolution of excitation temperature and density showed significant changes at various ambient pressure levels and these results were correlated to morphological changes seen in the plume images. Optimum signal to background ratios for emission lines were observed in the moderate pressure range (~ 1-10 Torr). Optical time-of-flight profiles were used to study time evolution of various species in the plume and noticed oscillations at intermediate pressure levels. Possible mechanisms for observed changes in plume shape, optical emission intensity, and dual peak structures in time-of-flight profiles were discussed.
Millimeter-scale laser channeling in underdense argon plasma diagnosed with K? x-ray imaging*
NASA Astrophysics Data System (ADS)
Kugland, N. L.; Constantin, C. G.; Doeppner, T.; Kemp, A.; Divol, L.; Glenzer, S. H.; Niemann, C.
Two-dimensional x-ray imaging of K? self-emission from laser-irradiated Ar gas jets has been used to study laser channeling and fast electron transport over millimeter-scale distances. We irradiated high density (10^20 cm-3 atomic density) supersonic Ar gas jets with an ultra-high intensity (10^19 W/cm^2), high power (100 TW class) 800 nm laser. K? fluorescence reveals a millimeter-scale laser channel, oriented along the laser axis, which ends in a forward-directed spray of fast electrons. K-shell x-ray spectroscopy diagnoses a spatially averaged mean ionization state of 6 ± 1 during the K? emission, implying an electron density of 0.5 nc. Study of this system can help understand the initial stage of the hole-boring approach to fast ignition, during which an intense laser pulse must propagate through a mm-scale moderately underdense plasma. *This work was performed under the auspices of the U.S. Department of Energy by the Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. Additional support was provided by LDRD grant 08-LW-004 and the DOE Plasma Physics Junior Faculty Award Program.
Dynamics of the spectral behaviour of an ultrashort laser pulse in an argon-gas-filled capillary discharge-preformed plasma channel
NASA Astrophysics Data System (ADS)
Sakai, S.; Higashiguchi, T.; Yugami, N.; Bobrova, N.; Sentoku, Y.; Kodama, R.
We have reported the argon plasma waveguide produced in an alumina (Al2O3) capillary discharge and used to guide ultrashort laser pulses at intensities of the order of 1016 W/cm2. A one-dimensional magnetohydrodynamic (MHD) code was used to evaluate the average degree of ionization of Ar in the preformed plasma channel. The spectrum of the propagated laser pulse in the Ar plasma waveguide was not modified and was well reproduced by a particle-in-cell (PIC) simulation under initial ion charge state of Ar3+ in the preformed plasma waveguide. The optimum timing for the laser pulse injection was around 150 ns after initiation of a discharge with a peak current of 200 A.
Hoffman, Maureane
The liver plays a key role in hemostasis as the site of synthesis of many of the proteins involved in the coagulation, antithrombotic and fibrinolytic systems that interact to both establish hemostasis, and preventing thrombosis. The common laboratory tests, prothrombin time (PT) and activated partial thromboplastin time (aPTT), evolved from studies of plasma clotting in test tubes. Such studies laid the basis for the coagulation cascade model of hemostasis. However, thought has evolved to place a greater emphasis on the active roles of cells in localizing and regulating hemostasis. The PT and aPTT do not reflect the roles of cellular elements in hemostasis, nor do they reflect the crucial roles of antithrombotic and fibrinolytic systems. Thus, though the PT may indeed reflect the synthetic capacity of the liver, it does not accurately reflect the risk of bleeding or thrombosis in patients with liver failure. PMID:26049068
Characterization and study of the thermodynamic equilibrium departure of an argon plasma flame produced by a surface-wave sustained discharge
NASA Astrophysics Data System (ADS)
Calzada, M. D.; Sáez, M.; García, M. C.
Surface wave induced plasma (SWP) is a particular class of microwave induced plasma. It is used in atomic emission and mass spectrometry as a source of excitation for the elemental analysis of samples in analytical chemistry. This discharge is mainly used at powers less than 300 W. At such low power, an efficient process of desolvation, atomization, excitation and ionization of the analyte can only be reached provided the density of power absorbed in the discharge is large. This requires a plasma whose volume increases very little with increasing absorbed power. At atmospheric pressure in the SWP, such a volume limitation can be achieved by having the plasma extending into ambient air in the form of a flame (open air discharge). This article presents the results of the experimental characterization and study of the degree of thermodynamic equilibrium of an argon plasma flame produced by a surfatron. The values of the plasma parameters and b(p) (departure from equilibrium) parameter for the ArI levels show that the discharge is a two-temperature plasma. By comparing the results with those obtained for a classical surface-wave plasma column, it can be concluded that the plasma in flame is more suited to be used as a source of excitation in analytical chemistry, due to its higher electronic density and temperatures values.
Two-dimensional profiles of electric fields in a radio frequency argon plasma above nonuniformities present on a surface
E. V. Barnat; G. A. Hebner
Laser-induced fluorescence-dip spectroscopy was used to measure two-dimensional (2-D) maps of the electric field present in an argon discharge above a ratio frequency-powered, nonuniform surface. Electric fields were obtained from experimentally measured Stark shifts of the energy of argon Rydberg states. The 2-D maps of the electric fields demonstrated that nonuniformities present on an electrode have long-range effects on the
Laser Optogalvanic Spectroscopy pf Neon and Argon in a Discharge Plasma and its Significance for Microgravity Combustion
NASA Technical Reports Server (NTRS)
Misra, Prabhakar; Haridass, C.; Major, H.
A detailed study of combustion mechanisms in flames, employing laser-based diagnostics, has provided good knowledge and understanding of the physical phenomena, and led to better characterization of the dynamical and chemical combustion processes, both under low-gravity (in space) and normal gravity (in ground based facilities, e.g. drop towers). Laser induced fluorescence (LIF), laser-induced incandescence (LII) and LIF thermometry have been widely used to perform nonintrusive measurements and to better understand combustion phenomena. Laser optogalvanic (LOG) spectroscopy has well-established applications in ion mobility measurements, atomic and molecular spectroscopy, ionization rates, recombination rates, velocity measurements and as a combustion probe for trace element detection. Absorption spectra of atomic and molecular species in flames can be obtained via LOG spectroscopy by measuring the voltage and current changes induced by laser irradiation. There are different kinds of processes that contribute to a discharge current, namely: (1) electron impact ionization, (2) collisions among the excited atoms of the discharge species and (3) Penning ionization. In general, at higher discharge currents, the mechanism of electron impact ionization dominates over Penning ionization, whereby the latter is hardly noticeable. In a plasma, whenever the wavelength of a laser coincides with the absorption of an atomic or molecular species, the rate of ionization of the species momentarily increases or decreases due to laser-assisted acceleration of collisional ionization. Such a rate of change in the ionization is monitored as a variation in the transient current by inserting a high voltage electrode into the plasma. Optogalvanic spectroscopy in discharges has been useful for characterizing laser line-widths and for providing convenient calibration lines for tunable dye lasers in the ultraviolet, visible and infrared wavelength regions. Different kinds of quantitative information, such as the electron collisional ionization rate, can be extracted from the complex processes occurring within the discharge. In the optogalvanic effect (OGE), there is no problem of overlap from background emissions, and hence even weak signals can be detected with a high signal-to-noise ratio, which makes the optogalvanic effect sensitive enough to resolve vibrational changes in molecular bonds and differences in energy levels brought about by different electron spins. For calibration purposes, neon and argon gaseous discharges have been employed most extensively, because these gases are commonly used as buffer gases within hollow-cathode lamps and provide an acceptable density of calibration lines. In the present work, our main aim has been to understand the dominant physical processes responsible for the production of the OGE signal, based on the extensive time resolved optogalvanic waveforms recorded, and also to extract quantitative information on the rates of excited state collisional processes.
Disseminated Intravascular Coagulation
... the NHLBI on Twitter. What Is Disseminated Intravascular Coagulation? Disseminated intravascular coagulation (ko-ag-u-LA-shun), or DIC, is ... This Content: NEXT >> November 2, 2011 Disseminated Intravascular Coagulation Clinical Trials Clinical trials are research studies that ...
COAGULATION Primary Hemostatic Plug
9/16/2013 1 COAGULATION Hemostasis HEMOSTASIS Primary Hemostatic Plug Secondary Homostatic Plug Extrinsic Pathway Common Pathway #12;9/16/2013 3 COAGULATION FACTORS Prothrombin Group Fibrinogen Group Coagulation #12;
Measurement of ^39Ar/Ar ratios using AMS on underground argon samples using the newly developed ultra-pure Al lined plasma chamber
NASA Astrophysics Data System (ADS)
Collon, P.; Bowers, M.; Calaprice, F.; Galbiati, C.; Jiang, C. L.; Henderson, D.; Kutschera, W.; Loosli, H. H.; Pardo, R.; Paul, M.; Rehm, E.; Robertson, D.; Schmitt, C.; Scott, R.; Vondrasek, R.; Lee, H. Y.
The first application of ^39Ar AMS at the ATLAS linac of Argonne National Laboratory (ANL) to date ocean water samples relevant to oceanographic studies was most successful and has been reported on. In particular the use of a quartz liner in the plasma chamber of the Electron Cyclotron Resonance (ECR) ion source enabled a potassium reduction of a factor ˜100 compared to previous runs without liners and allowed measurements down to ^39Ar/Ar = 4.2x10-17. We are currently working on improving the AMS method for ^39Ar by following two ion source development paths to allow for higher Ar beam currents coupled to lower ^39K background rates. Both methods are combined with new cleaning techniques developed for removing both particulates and other materials from surfaces, largely driven by the semiconductor industry. The driving force for the use of AMS to measure ^39Ar is to search for a source of argon that has a low concentration of ^39Ar. Such a source of argon would be useful for new liquid argon detectors that are being developed for detecting dark matter WIMPs (Weakly Interacting Massive Particle), such as that to be installed at the new DUSEL (Deep Underground Science and engineering laboratory) facility at Homestake in the US.
Fractal Coagulation Bruce E. Logan
Fractal Coagulation Kinetics Bruce E. Logan Department of Civil & Environmental Engineering can basis of calculations be improved? #12;Coagulation No collisions Unsuccessful collisions Successful collisions & coagulation #12;Coagulation Theory ·Coagulation theory is quite old, dating back
First principles transport coefficients and reaction rates of Ar_2^+ ions in argon for cold plasma jet modeling
NASA Astrophysics Data System (ADS)
Chicheportiche, Alexandre; StachoÅ, Martin; Benhenni, Malika; Gadéa, Florent Xavier; Kalus, René; Yousfi, Mohammed
Momentum-transfer collision cross-sections and integral collision cross-sections for the collision-induced dissociation are calculated for collisions of ionized argon dimers with argon atoms using a nonadiabatic semiclassical method with the electronic Hamiltonian calculated on the fly via a diatomics-in-molecules semiempirical model as well as inverse-method modeling based on simple isotropic rigid-core potential. The collision cross-sections are then used in an optimized Monte Carlo code for evaluations of the Ar_2^+ mobility in argon gas, longitudinal diffusion coefficient, and collision-induced dissociation rates. A thorough comparison of various theoretical calculations as well as with available experimental data on the Ar_2^+ mobility and collision cross-sections is performed. Good agreement is found between both theoretical approaches and the experiment. Analysis of the role of inelastic processes in Ar_2^+/Ar collisions is also provided.
First principles transport coefficients and reaction rates of Ar2(+) ions in argon for cold plasma jet modeling.
Chicheportiche, Alexandre; Stacho?, Martin; Benhenni, Malika; Gadéa, Florent Xavier; Kalus, René; Yousfi, Mohammed
Momentum-transfer collision cross-sections and integral collision cross-sections for the collision-induced dissociation are calculated for collisions of ionized argon dimers with argon atoms using a nonadiabatic semiclassical method with the electronic Hamiltonian calculated on the fly via a diatomics-in-molecules semiempirical model as well as inverse-method modeling based on simple isotropic rigid-core potential. The collision cross-sections are then used in an optimized Monte Carlo code for evaluations of the Ar 2 (+) mobility in argon gas, longitudinal diffusion coefficient, and collision-induced dissociation rates. A thorough comparison of various theoretical calculations as well as with available experimental data on the Ar 2 (+) mobility and collision cross-sections is performed. Good agreement is found between both theoretical approaches and the experiment. Analysis of the role of inelastic processes in Ar 2 (+)/Ar collisions is also provided. PMID:25296801
Ultraviolet versus infrared: Effects of ablation laser wavelength on the expansion of laser-induced plasma into one-atmosphere argon gas
NASA Astrophysics Data System (ADS)
Ma, Qianli; Motto-Ros, Vincent; Laye, Fabrice; Yu, Jin; Lei, Wenqi; Bai, Xueshi; Zheng, Lijuan; Zeng, Heping
Laser-induced plasma from an aluminum target in one-atmosphere argon background has been investigated with ablation using nanosecond ultraviolet (UV: 355 nm) or infrared (IR: 1064 nm) laser pulses. Time- and space-resolved emission spectroscopy was used as a diagnostics tool to have access to the plasma parameters during its propagation into the background, such as optical emission intensity, electron density, and temperature. The specific feature of nanosecond laser ablation is that the pulse duration is significantly longer than the initiation time of the plasma. Laser-supported absorption wave due to post-ablation absorption of the laser radiation by the vapor plume and the shocked background gas plays a dominant role in the propagation and subsequently the behavior of the plasma. We demonstrate that the difference in absorption rate between UV and IR radiations leads to different propagation behaviors of the plasma produced with these radiations. The consequence is that higher electron density and temperature are observed for UV ablation. While for IR ablation, the plasma is found with lower electron density and temperature in a larger and more homogenous axial profile. The difference is also that for UV ablation, the background gas is principally evacuated by the expansion of the vapor plume as predicted by the standard piston model. While for IR ablation, the background gas is effectively mixed to the ejected vapor at least hundreds of nanoseconds after the initiation of the plasma. Our observations suggest a description by laser-supported combustion wave for the propagation of the plasma produced by UV laser, while that by laser-supported detonation wave for the propagation of the plasma produced by IR laser. Finally, practical consequences of specific expansion behavior for UV or IR ablation are discussed in terms of analytical performance promised by corresponding plasmas for application with laser-induced breakdown spectroscopy.
Convoluted effect of laser fluence and pulse duration on the property of a nanosecond laser-induced plasma into an argon ambient gas at the atmospheric pressure
NASA Astrophysics Data System (ADS)
Bai, Xueshi; Ma, Qianli; Motto-Ros, Vincent; Yu, Jin; Sabourdy, David; Nguyen, Luc; Jalocha, Alain
We studied the behavior of the plasma induced by a nanosecond infrared (1064 nm) laser pulse on a metallic target (Al) during its propagation into argon ambient gas at the atmospheric pressure and especially over the delay interval ranging from several hundred nanoseconds to several microseconds. In such interval, the plasma is particularly interesting as a spectroscopic emission source for laser-induced plasma spectroscopy (LIBS). We show a convoluted effect between laser fluence and pulse duration on the structure and the emission property of the plasma. With a relatively high fluence of about 160 J/cm2 where a strong plasma shielding effect is observed, a short pulse of about 4 ns duration is shown to be significantly more efficient to excite the optical emission from the ablation vapor than a long pulse of about 25 ns duration. While with a lower fluence of about 65 J/cm2, a significantly more efficient excitation is observed with the long pulse. We interpret our observations by considering the post-ablation interaction between the generated plume and the tailing part of the laser pulse. We demonstrate that the ionization of the layer of ambient gas surrounding the ablation vapor plays an important role in plasma shielding. Such ionization is the consequence of laser-supported absorption wave and directly dependent on the laser fluence and the pulse duration. Further observations of the structure of the generated plume in its early stage of expansion support our explanations.
Surface modification of poly(3,4-ethylene dioxthiophene):poly(styrene sulfonic acid) (PEDOT:PSS) films by atmospheric-pressure argon plasma for organic thin-film solar cells.
Ino, Tomohisa; Hayashi, Tatsuya; Fukuda, Takeshi; Ueno, Keiji; Shirai, Hajime
Highly-conductive poly(3,4-ethylene dioxythiophene):poly(styrene sulfonic acid) (PEDOT:PSS) films obtained by the addition of dimethylsulfoxide (DMSO) and the argon plasma exposure were used as a transparent conductive anode (TCA) for copper-phthalocyanine (CuPc)/C60 organic thin-film solar cells (OSCs). The CuPc/C60 OSCs on as-grown DMSO added PEDOT:PSS layer showed a power efficiency of 0.6%, whereas it was improved markedly to 1.34% after the atmospheric-pressure argon plasma exposure, which was comparable to that formed on indium-tin-oxide layer. Effects of the DMSO addition and the argon plasma exposure in the spin-coated PEDOT:PSS films is demonstrated in terms of the in-depth characterization of optical and electrical properties. PMID:22097525
Element- and charge-state-resolved ion energies in the cathodic arc plasma from composite AlCr cathodes in argon, nitrogen and oxygen atmospheres
Franz, Robert; Polcik, Peter; Anders, André
The energy distribution functions of ions in the cathodic arc plasma using composite AlCr cathodes were measured as a function of the background gas pressure in the range 0.5 to 3.5 Pa for different cathode compositions and gas atmospheres. The most abundant aluminium ions were Al+ regardless of the background gas species, whereas Cr2+ ions were dominating in Ar and N2 and Cr+ in O2 atmospheres. The energy distributions of the aluminium and chromium ions typically consisted of a high-energy fraction due to acceleration in the expanding plasma plume from the cathode spot and thermalised ions that were subjected to collisions in the plasma cloud. The fraction of the latter increased with increasing background gas pressure. Atomic nitrogen and oxygen ions showed similar energy distributions as the aluminium and chromium ions, whereas the argon and molecular nitrogen and oxygen ions were formed at greater distance from the cathode spot and thus less subject to accelerating gradients. In addition to the positively charged metal and gas ions, negatively charged oxygen and oxygen-containing ions were observed in O2 atmosphere. The obtained results are intended to provide a comprehensive overview of the ion energies and charge states in the arc plasma of AlCr composite cathodes in different gas atmospheres as such plasmas are frequently used to deposit thin films and coatings. PMID:26120236
Modeling of particle coagulation in low pressure PECVD
U. Bhandarkar; U. Kortshagen
Contaminant particles generated in plasmas used to manufacture semiconductor devices can potentially destroy micro-electronic circuits. Particles of micrometer-size in a plasma are usually negatively charged due to the higher mobility of electrons. Like charges on the particles should inhibit growth by coagulation. However, the coagulation rates of nanometer-sized particles observed experimentally are even higher than the thermal coagulation rates of
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SUPPLEMENTARY INFORMATION FOR Spatial Localization of Bacteria Controls Coagulation of Human Blood by "Quorum Acting"
Ismagilov, Rustem F.
1 SUPPLEMENTARY INFORMATION FOR Spatial Localization of Bacteria Controls Coagulation of Human coagulation of plasma deficient in von Willebrand factor and platelets, but not plasma deficient factor X and prothrombin. (a-c) Graphs quantifying the activation of coagulation factors prothrombin (a
Histidine-rich glycoprotein: A novel adaptor protein in plasma that modulates the immune, vascular and coagulation systems
Allison L Jones; Mark D Hulett; Christopher R Parish
Histidine-rich glycoprotein (HRG) is an abundant plasma glycoprotein that has a multidomain structure, interacts with many ligands, and has been shown to regulate a number of important biological processes. HRG ligands include Zn2+ and haem, tropomyosin, heparin and heparan sulphate, plasminogen, plasmin, fibrinogen, thrombospondin, IgG, Fc?R and complement. In many cases, the histidine-rich region of the molecule enhances ligand binding
Influence of low energy argon plasma treatment on the moisture barrier performance of hot wire-CVD grown SiNx multilayers
NASA Astrophysics Data System (ADS)
Majee, Subimal; Fátima Cerqueira, Maria; Tondelier, Denis; Geffroy, Bernard; Bonnassieux, Yvan; Alpuim, Pedro; Bourée, Jean Eric
The reliability and stability are key issues for the commercial utilization of organic photovoltaic devices based on flexible polymer substrates. To increase the shelf-lifetime of these devices, transparent moisture barriers of silicon nitride (SiNx) films are deposited at low temperature by hot wire CVD (HW-CVD) process. Instead of the conventional route based on organic/inorganic hybrid structures, this work defines a new route consisting in depositing multilayer stacks of SiNx thin films, each single layer being treated by argon plasma. The plasma treatment allows creating smoother surface and surface atom rearrangement. We define a critical thickness of the single layer film and focus our attention on the effect of increasing the number of SiNx single-layers on the barrier properties. A water vapor transmission rate (WVTR) of 2 × 10-4 g/(m2·day) is reported for SiNx multilayer stack and a physical interpretation of the plasma treatment effect is given.
Surface force measurements between titanium dioxide surfaces prepared by atomic layer deposition in electrolyte solutions reveal non-DLVO interactions: influence of water and argon plasma cleaning.
Walsh, Rick B; Evans, Drew; Craig, Vincent S J
Surface force measurements between titania surfaces in electrolyte solutions have previously revealed an unexplained long-range repulsive force at high pH, not described by Derjaguin, Landau, Verwey, and Overbeek (DLVO) theory. Here, the surface forces between titania surfaces produced by atomic layer deposition (ALD) and cleaned using a variety of methods have been measured to determine the influence of the cleaning protocol on the measured forces and test the hypothesis that water plasma cleaning of the surface results in non-DLVO forces at high pH. For argon plasma and water plasma cleaned surfaces, a diffuse double layer repulsion and van der Waals attraction is observed near the isoelectric point. At high pH, the force remained repulsive up until contact, and no van der Waals attraction or adhesion was observed. Differences in the measured forces are explained by modification of the surface chemistry during cleaning, which alters the density of charged groups on the surface, but this cannot explain the observed disagreement with DLVO theory at high pH. PMID:24548170
The determination of ranges of selected properties of an argon plasma using an electric arc of limited power
Farquhar, Bannister Wells
Discussion of Results VII Conclusions VIII Presentation of Data 20 24 26 33 35 References LIST OF FIGURES Figure Page Cathode Rear Plate Nozzle Flange 0 8 10 3A Collar and Cap Nozzle Schematic of Plasma Generator Energy Losses for Various... Energy Inputs Range of Plasmas Generated 0 12 15 27 28 Close-up of Arc Chamber and Plasma Jet. . . , 41 Over-all View of Plasma Generator 41 10 The Arc Chamber, Control Console and Instrumentation 42 Exploded View of Nozzle Flange, Nozzle...
Characterization of the gene for the a subunit of human factor XIII (plasma transglutaminase), a blood coagulation factor
Ichinose, A.; Davie, E.W. (Univ. of Washington, Seattle (USA))
Factor XIII (plasma transglutaminase, fibrin stabilizing factor) is a glycoprotein that circulates in blood as a tetramer (a{sub 2}b{sub 2}) consisting of two a and two b subunits. The primary structures of the a and b subunits of human factor XIII have been reported by a combination of cDNA cloning and amino acid sequence analysis. To establish the gene structure of the a subunit for factor XIII, several human genomic libraries were screened by using the cDNA encoding the a subunit as a probe. Among {approx}5 {times} 10{sup 7} recombinant phage, 121 have been shown to contain an insert encoding a portion of the a subunit. Twenty-five unique clones were than characterized by restriction mapping, Southern blotting, and DNA sequencing. Overlapping clones encoding the a subunit of factor XIII span >160 kilobases. DNA sequence analysis revealed that the activation peptide released by thrombin, the active site cysteine region, the two putative calcium-binding regions, and the thrombin cleavage site leading to inactivation are encoded by separate exons. This suggest that the introns may separate the a subunit into functional and structural domains. A comparison of the amino acid sequence deduced from the genomic DNA sequence with those deduced from cDNA or determined by amino acid sequence analysis of the plasma and placental proteins revealed apparent amino acid polymorphisms in six positions of the polypeptide chain of the a subunit.
An argon-ion laser achieves low output power by using a plasma guide and mirror configuration which restricts lasing action to a portion of the resonator cavity at relatively high conversion efficiency.
Departure from Local Thermodynamic Equilibrium in argon plasmas sustained in a Torche à Injection Axiale sur Guide d'Ondes
NASA Astrophysics Data System (ADS)
Rincón, R.; Muñoz, J.; Calzada, M. D.
Plasma torches are suitable plasma sources for a wide range of applications. The capability of these discharges to produce processes like sample excitation or decomposition of molecules inside them depends on the density of the plasma species and their energies (temperatures). The relation between these parameters determines the specific state of thermodynamic equilibrium in the discharge. Thus, the understanding of plasma possibilities for application purposes is related to the knowledge of the plasma thermodynamic equilibrium degree. In this paper a discussion about the equilibrium state for Ar plasmas generated by using a Torche à Injection Axiale sur Guide d'Ondes, TIAGO device, is presented. Emission spectroscopy techniques were used to measure gas temperature and electron density at the exit of the nozzle torch and along the dart. Boltzmann-plots as well as bp parameters were calculated to characterize the type and degree of departure from partial Local Saha Equilibrium (pLSE). This study indicates that the closer situation to Local Thermodynamic Equilibrium (LTE) of the plasma corresponds to larger Ar flows which highlights the importance of the nitrogen (atmosphere surrounding the plasma) in the kinetics of Ar-TIAGO discharges.
Solution nebulization into a low-power argon microwave-induced plasma for atomic emission spectrometry: study of synthetic ocean water
Ng, K.C.; Shen, W.
A MAK nebulizer is used to introduce liquid aerosols containing Cr, Mn, In, V, Pb, Sr, or Zr into a low-power (105-115 W), low argon flow (537 mL/min) microwave-induced plasma for atomic emission spectrometry. Detection limits (3sigma) in 3% nitric acid water samples are at the parts-per-billion level (62, 18, 18, 91, 139, 13, and 3945, respectively). These values compared favorably to those reported for a 150-W Ar-MIP and the conventional inductively coupled plasma for most of the elements. In a 10% synthetic ocean water matrix, signal enhancement is obtained for Cr, Mn, In, Pb, and Sr, and signal depression is found for V and Zr. Detection limits (parts per billion) in the 10% ocean water are 9, 3, 6, 1780, 54, 2, and not measurable, for Cr, Mn, In, V, Pb, Sr, and Zr, respectively. The signal precision is typically 2% RSD for 1 ppm solutions. Linear responses (>3 orders of magnitude) are associated with all of the tested analyte concentrations of water or synthetic ocean matrices.
Observation of inactivation of Bacillus sbtilis spores under exposures of oxygen added argon atmospheric pressure plasma jet
NASA Astrophysics Data System (ADS)
Shen, Jie; Cheng, Cheng; Zhao, Ying; Xiao, Dezhi; Lan, Yan; Xie, Hongbing; Cheng, Junli; Meng, Yuedong; Li, Jiangang; Chu, Paul K.
The inactivation of Bacillus subtilis spores by an Ar plasma jet mixed with different amounts of oxygen is reported. 5.8 × 106 B. subtilis spores are sterilized by an Ar/O2 (8.7%) plasma jet after exposure for 2 min. The densities of ozone and oxygen radicals in the Ar/O2 plasma jet increase with oxygen concentration and are estimated by optical spectroscopy diagnostic. The malondialdehyde (MDA) test shows that oxygen radicals participate in bacterial inactivation. Scanning electron microscopy (SEM) reveals the deformation of the spore shape due to etching by oxygen radicals and the dependence of the degree of deformation on the density of oxygen radicals.
Effect of Argon\\/Hydrogen Plasma Cleaning on Electroless Ni Deposition on Small-Area Al Pads
Akihiro Ikeda; Kouhei Kajiwara; Naoya Watanabe; Tanemasa Asano
We investigated effect of Ar\\/H2 plasma cleaning on electroless Ni under-bump metallurgy (UBM) layer formation on small-area Al pads. When 5 × 5 mum2 pads are cleaned with the plasma, electroless Ni grows successfully on them, whereas no growth occurs on pads cleaned with conventional wet chemicals. In the Ni-UBM layer formation process, Zn is deposited by displacement plating on
Numerical Modeling of a Pulsed Argon-Silane RF Plasma with Biased Substrate for High-Velocity Deposition of Nanoparticles
NASA Astrophysics Data System (ADS)
Girshick, Steven; Larriba-Andaluz, Carlos
It has been hypothesized that deposition of very small silicon nanoparticles during plasma-enhanced chemical vapor deposition of silicon, under conditions where the particle impact velocity is high enough to cause particle melting/amorphization, can lead to epitaxial film growth at low temperature. One way to accomplish this might be by pulsing the RF plasma and applying a positive DC bias during the afterglow of each pulse. The negatively charged particles, trapped in the plasma during the ON phase of each pulse, are accelerated to the substrate during the afterglow. To assess the feasibility of such an approach, we conducted numerical simulations of a pulsed capacitively-coupled RF Ar-silane plasma. We used a modified version of a previously reported 1D model, in which a nanodusty plasma is simulated by self-consistently coupling models for the plasma, chemistry and aerosol. Preliminary results indicate that the approach is feasible, but that parameters such as pulse frequency and duty cycle are important in limiting particle growth and in maximizing fluxes of energetic nanoparticles to the substrate. Partially supported by US Dept. of Energy Office of Fusion Energy Science (DE-SC0001939) and US National Science Foundation (CHE-124752).
2D collisional-radiative model for non-uniform argon plasmas: with or without 'escape factor'
NASA Astrophysics Data System (ADS)
Zhu, Xi-Ming; Vaskov Tsankov, Tsanko; Luggenhölscher, Dirk; Czarnetzki, Uwe
Collisional-radiative models for excited rare-gas atoms in low-temperature plasmas are a widely investigated topic. When these plasmas are optically thick, an 'escape factor' is introduced into the models to account for the reabsorption of photons (so-called radiation trapping process). This factor is usually obtained assuming a uniform density profile of the excited species; however, such an assumption is often not satisfied in a bounded plasma. This article reports for the first time a self-consistent collisional-radiative model without using an ad hoc 'escape factor' for excited Ar atoms in the 2p states (in Paschen's notation). Rather, the rate balance equations—i.e. the radiation transfer equations—of the 2p states are numerically solved to yield the actual density profiles. The predictions of this self-consistent model and a model based on the escape factor concept are compared with spatially-resolved emission measurements in a low-pressure inductive Ar plasma. The self-consistent model agrees well with the experiment but the 'escape factor' model shows considerable deviations. By the comparative analysis the limitations and shortcomings of the escape factor concept as adopted in a significant number of works are revealed.
Depth Profile Characterization of Spin-Coated Poly(3,4-ethylenedioxythiophene):Poly(styrene sulfonic acid) Films for Thin-Film Solar Cells during Argon Plasma Etching by Spectroscopic Ellipsometry
Tomohisa Ino; Tatsuya Hayashi; Keiji Ueno; Hajime Shirai
Depth profiles of the optical constants, carrier mobility, and carrier density of spin-coated poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid) (PEDOT:PSS) films were investigated by real-time characterization by spectroscopic ellipsometry (SE) during argon plasma etching at atmospheric pressure. Spectral analysis revealed that homogeneous etching occurred within 10--15 nm of the top surface, followed by the appearance of a conductive PEDOT phase and surface roughening,
The role of platelets in blood coagulation during thrombus formation in flow
The role of platelets in blood coagulation during thrombus formation in flow A. Tosenberger1,2 , F of aggregating platelets with biochemical reactions in plasma that participate in blood coagulation out the reactants participating in blood coagulation. Platelets covered by the fibrin network cannot
Coagulation equations with gelation
E. M. Hendriks; M. H. Ernst; R. M. Ziff
Smoluchowski's equation for rapid coagulation is used to describe the kinetics of gelation, in which the coagulation kernelKij models the bonding mechanism. For different classes of kernels we derive criteria for the occurrence of gelation, and obtain critical exponents in the pre- and postgelation stage in terms of the model parameters; we calculate bounds on the time of gelationtc, and
Density of atoms in Ar*(3p{sup 5}4s) states and gas temperatures in an argon surfatron plasma measured by tunable laser spectroscopy
Huebner, S.; Carbone, E. A. D.; Mullen, J. J. A. M. van der [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven (Netherlands); Sadeghi, N. [LIPhy, Universite Joseph Fourier and CNRS, UMR 5588, Grenoble F-38041 (France)
This study presents the absolute argon 1 s (in Paschens's notation) densities and the gas temperature, T{sub g}, obtained in a surfatron plasma in the pressure range 0.65
10 mbar, for which the pressure broadening can no more be neglected. T{sub g} is in the range of 480-750 K, increasing with pressure and decreasing with the distance from the microwave launcher. Taking into account the line of sight effects of the absorption measurements, a good agreement is found with our previous measurements by Rayleigh scattering of T{sub g} at the tube center. In the studied pressure range, the Ar(4 s) atom densities are in the order of 10{sup 16}-10{sup 18} m{sup -3}, increasing towards the end of the plasma column, decreasing with the pressure. In the low pressure side, a broad minimum is found around 10
Preliminary investigation of a medium power argon radiofrequency capacitively coupled plasma as atomization cell in atomic fluorescence spectrometry of cadmium.
Frentiu, Tiberiu; Darvasi, Eugen; Senila, Marin; Ponta, Michaela; Cordos, Emil
The single ring electrode radiofrequency capacitively coupled plasma torch (SRTr.f.CCP) operated at 275W, 27.12 MHz and Ar flow rate below 0.7 lmin(-1) was investigated for the first time as atomization cell in atomic fluorescence spectrometry (AFS) using electrodeless discharge lamps (EDL) as primary radiation source and charged coupled devices as detector. The signal to background ratio (SBR) and limit of detection for Cd determination by EDL-SRTr.f.CCP-AFS were compared to those obtained in atomic emission spectrometry using the same plasma torch. The detection limit in fluorescence was 4.3 ngml(-1) Cd compared to 65 ngml(-1) and 40 ngml(-1) reported in r.f.CCP-atomic emission (AES) equipped with single or double ring electrode. The lower detection limit in EDL-SRTr.f.CCP-AFS is due to a much better SBR in fluorescence. The limit of detection was also compared to those in atomic fluorescence with inductively coupled plasma (0.4 ngml(-1)), microwave plasma torch (0.25 ngml(-1)) and air-acetylene flame (8 ngml(-1)). The influence of light-scattering through the plasma and the secondary reflection of the primary radiation on the wall of the quartz tube on the analytical performance are discussed. The non-spectral matrix effects of Ca, Mg and easily ionized elements are much lower in EDL-SRTr.f.CCP-AFS compared to SRTr.f.CCP-AES. The new technique was applied in the determination of Cd in contaminated soils, industrial hazardous waste (0.4-370 mgkg(-1)) and water (113 microgl(-1)) with repeatability of 4-8% and reproducibility in the range of 5-12%, similar to those in ICP-AES. The results were checked by the analysis of a soil and water CRM with a recovery degree of 97+/-9% and 98+/-4%, for a confidence limit of 95%. The present EDL-SRTr.f.CCP-AFS is a promising technique for Cd determination in environmental samples. PMID:18761173
Jagneaux, Tonya; Taylor, David E; Kantrow, Stephen P
Activation of the coagulation cascade during invasive infection can result in purpura fulminans, with rapid progression of tissue ischemia, or may manifest as abnormal clotting indices alone. Although severe derangements in coagulation are associated with organ dysfunction and increased mortality, the contribution of coagulopathy to the pathophysiology of sepsis remains incompletely understood. Over the past decade, investigators have evaluated several therapeutic anticoagulant strategies in sepsis, and manipulation of the coagulation system has emerged as a key concept in the current management of this disease. Clinical observations during treatment of septic patients with the endogenous anticoagulant activated protein C have stimulated additional study of interactions between endothelial injury, coagulation, and inflammation. This review describes clotting abnormalities during sepsis and discusses the clinical experience with therapeutic strategies intended to oppose excessive coagulation. PMID:15486534
Muzzio, F.J.; Ottino, J.M.
We study coagulation in the flow field of a time-periodic deterministic chaotic flow and focus on the simplest case: point particles convected without diffusion and allowed to coagulate with probability 1 when the distance is less than d. An analysis of the underlying physics is presented. Under ''well-mixed'' conditions the system behaves as if the particles were moved by Brownian motion, and a simple kinetic model describes the main results. The poorly mixed case is considerably more complex. Spatial inhomogeneities result from competition between the rate of coagulation and mixing, and trapping and leaking of clusters due to Kolmogorov-Arnold-Moser surfaces.
NASA Technical Reports Server (NTRS)
Chokshi, Arati; Tielens, Alexander G. G. M.; Hollenbach, David
Coagulation is an important mechanism in the growth of interstellar and interplanetary dust particles. The microphysics of the coagulation process was theoretically analyzed as a function of the physical properties of the coagulating grains, i.e., their size, relative velocities, temperature, elastic properties, and the van der Waal interaction. Numerical calculations of collisions between linear chains provide the wave energy in individual particles and the spectrum of the mechanical vibrations set up in colliding particles. Sticking probabilities are then calculated using simple estimates for elastic deformation energies and for the attenuation of the wave energy due to absorption and scattering processes.
Etch product dynamics of polyphenylene oxide laminates using a carbon tetra fluoride/oxygen/argon downstream microwave plasma
NASA Astrophysics Data System (ADS)
Hsu, Chia-Chang
A downstream microwave plasma etcher has been constructed to study the etch dynamics of polyphenylene oxide laminates (PPO) using CF4/O 2/Ar reactant gases. The results of optical emission spectroscopy indicate that both atomic fluorine and atomic oxygen participate in the etching process. Quantitative analysis of downstream etch products based on the real time measurement of molecular-beam mass spectrometry shows major etch products of CO, CO 2 and HF. A linear correlation between weight loss measurements of PPO laminates and the integration of CO and CO2 etch products with respect to processing time suggests that the study of etch dynamics can be achieved. Additionally, XPS results show more fluorinated carbons on the surface etched with 30% CF4 than with 10% CF4. The etch rate changes more with processing time as CF4% increases. The dynamic reduction in rate becomes significant at CF4 ? 10% for a pressure of 0.2 torr, and CF4 ? 20% for 0.5 and 0.8 torr. At temperatures of 50 to 180°C, the etching process exhibits an activation energy of 0.80 cal/mole and shows similar dynamics. The average etch rate increases with flow rate from 30 to 60 sccm. A greater reduction in etch rate with process time is also found. CO is the major etch product at low CF4% while CO2 dominates at high CF4. It is proposed that CO is the primary product of nonfluorinated polymers while CO2 could be produced by recombination of CO and O through fluorinated surfaces. A one-dimensional model has been developed to analyze the concentrations of reactive species in the downstream microwave plasma etcher. Electron impact dissociation reactions, homogeneous chemistry and wall recombination reactions are included. The general experimental trends are predicted by the model. A three-step mechanism (initiation, etching and passivation) is used to develop an unsteady state model for the surface kinetics. The reaction rate constants are estimated using computed concentrations of reactive precursors based on the one-dimensional model. The values of constants suggest that the initial etch rate is controlled by the initiation and etching steps while the dynamic reduction is governed by the passivation step.
Characterization of the behavior of chemically reactive species in a nonequilibrium inductively coupled argon-hydrogen thermal plasma under pulse-modulated operation
Ye, Rubin; Ishigaki, Takamasa; Taguchi, Hiroyuki; Ito, Shigeru; Murphy, Anthony B.; Lange, Hubert [Nano Ceramics Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Department of Pure and Applied Chemistry, Tokyo University of Science, Yamazaki, Noda, Chiba 278-8510 (Japan); CSIRO Industrial Physics, P.O. Box 218, Lindfield, New South Wales 2070 (Australia); Department of Chemistry, Warsaw University, Pasteur Street 1, 02-093 Warsaw (Poland)
The temporal and spatial dependence of species densities in a pulse-modulated inductively coupled plasma (PM-ICP) in an argon-hydrogen mixture was investigated by means of numerical modeling, taking into account time dependence, two temperatures, and chemical nonequilibrium, and also through spectroscopic measurements. Conservation equations for mass, momentum, electron energy, heavy-species energy, each species, and the electromagnetic field were developed and solved self-consistently. The transient behavior of the mass fraction of each species was determined by including chemical kinetics source terms in the species conservation equations. Fourteen chemical reactions involving seven species (e, Ar, Ar{sup +}, H{sub 2}, H{sub 2}{sup +}, H, and H{sup +}) were considered. The transport properties were evaluated based on the local species densities using the first-order approximation of the Chapman-Enskog method. Time-resolved electron density profiles were obtained from measurements of the Stark broadening of the H{sub {beta}} line (486.1 nm), performed using an optical system positioned using a stepper motor. The investigations were conducted for a maximum power level of 11.7 kW with a duty factor of 66.7% and at a pressure of 27 kPa. Reasonable agreement was found between the predicted and measured electron densities. The electron density in the discharge region varied considerably over a pulse cycle, while the hydrogen atom density remained high throughout the cycle, and peaked in a region that has been experimentally demonstrated to have optimal efficiency for hydrogen doping of materials. The main mechanisms responsible for the production of the relevant species in the PM-ICP are discussed.
Two dimensional profiles of electric fields in a radio-frequency argon plasma above non-uniformities present on a surface.
Hebner, Gregory Albert; Barnat, Edward V.
Laser-induced fluorescence-dip spectroscopy was used to measure two-dimensional (2-D) maps of the electric field present in an argon discharge above a ratio frequency-powered, nonuniform surface. Electric fields were obtained from experimentally measured Stark shifts of the energy of argon Rydberg states. The 2-D maps of the electric fields demonstrated that nonuniformities present on an electrode have long-range effects on the structure of the sheath.
Leukocyte Elastase Release during Blood Coagulation
Plow, Edward F.
Immunological detection of elastase, an enzyme present within leukocyte granules, has been used as a marker for polymorphonuclear leukocyte activation. Polymorphonuclear leukocytes contained 4.6 ?g/107 cells, whereas erythrocytes, mononuclear cells, and platelets contained <1% of this level. In plasma that was separated from blood cells after 1 h at 22°C, the mean level of elastase-related antigen in seven normal donors was 25±6 ng/ml. This level was unaltered by immediate separation of the plasma from the cells, by inclusion of protease inhibitors, or by anticoagulation of the plasma with either EDTA or acidcitrate-dextrose (the level in heparinized plasma was approximately threefold higher). In serum, the level of elastase-related antigen was 288±125 ng/ml, representing an 11.5-fold increase above plasma levels. The antigen detected in serum was immunochemically indistinguishable from the leukocyte enzyme. Release of elastase was observed when isolated polymorphonuclear leukocytes were added to nonanticoagulated platelet-rich or platelet-poor plasma, recalcified plasma, or to serum. Addition of a chelating agent to serum prevented elastase release, but calcium or magnesium did not induce release in the absence of plasma. Coagulation induced by addition of thrombin to plasma also failed to induce release. In whole blood or in anticoagulated plasma reconstituted with polymorphonuclear leukocytes and then recalcified, initial release of elastase occurred concomitantly with or slightly after clotting and reached maximal levels within 20-40 min after clot formation. The data indicates that early events in coagulation or other pathways that occur in parallel with coagulation induce leukocyte release. The release of elastase, a major fibrinolytic protease of leukocytes, from the cells provides a mechanism for this enzyme or other granule proteases to participate in physiological events. Images PMID:6916769
Characterization of the coagulation system in healthy dolphins: the coagulation factors, natural anticoagulants, and fibrinolytic products
Rita F. Tibbs; M. Tarek Elghetany; Lethu T. Tran; W. Van Bonn; T. Romano; Daniel F. Cowan
In dolphins, blood pooling and acidosis from lack of oxygenation with prolonged underwater stay are not associated with intravascular clotting as it would be in terrestrial mammals, while shed blood clots promptly, and intravascular clots form after death. This intriguing physiologic adaptation prompted further investigation of the coagulation system in the dolphin. We studied the plasma from 17 dolphins (Tursiops
Mischler, Stéphane
LIAPUNOV FUNCTIONALS FOR SMOLUCHOWSKI'S COAGULATION EQUATION AND CONVERGENCE TO SELF to self-similar profiles for solutions to the Smoluchowski coagulation equation with constant coagulation Liapunov functionals are identified. Keywords. Coagulation, self-similar solution, Liapunov functional AMS
Argon/UF6 plasma exhaust gas reconstitution experiments using preheated fluorine and on-line diagnostics. [fissioning uranium plasma core reactor design
NASA Technical Reports Server (NTRS)
Roman, W. C.
The feasibility of employing a flowing, high-temperature, pure fluorine/UF6 regeneration system to efficiently convert a large fraction of the effluent plasma exhaust back to pure UF6 was demonstrated. The custom built T.O.F. mass spectrometer sampling system permitted on-line measurements of the UF6 concentration at different locations in the exhaust system. Negligible amounts ( 100 ppm) of UF6 were detected in the axial bypass exhaust duct and the exhaust ducts downstream of the cryogenic trap system used to collect the UF6, thus verifying the overall system efficiency over a range of operating conditions. Use of a porous Monel duct as part of the exhaust duct system, including provision for injection of pure fluorine, provided a viable technique to eliminate uranium compound residue on the inside surface of the exhaust ducts. Typical uranium compound mass deposition per unit area of duct was 2 micron g/sq cm. This porous duct technique is directly applicable to future uranium compound transfer exhaust systems. Throughout these experiments, additional basic data on the corrosion aspects of hot, pressurized UF6/fluorine were also accumulated.
Coagulant control in water treatment
Optimization of coagulant dosage in water treatment is becoming more critical as a result of increased attention to removal of micropollutants, THM precursors, and pathogens resistant to disinfection. At the same time, the availability of a large number of coagulants, flocculants, and other additives, and the recent introduction of technologies for the continuous characterization of coagulated flows, has increased the
Simulation program for wastewater coagulation
H. Ratnaweera; L. Lei; O. Lindholm
The lack of comprehensive simulation models for wastewater coagulation is one of the obstacles to achieving optimal coagulant dosing. Two approaches for developing a model to describe the coagulation process are presented. The comprehensiveness in describing the influent quality with several parameters, rather than with one parameter, is identified to give high efficiency in dosing models based on algorithms constructed
5, 38473872, 2005 Coagulation of
Paris-Sud XI, Université de
ACPD 5, 38473872, 2005 Coagulation of nanoparticles H.-H. Grotheer et al. Title Page Abstract Coagulation of combustion generated nanoparticles and their measurement behind vehicle engines: can they play. 3847 #12;ACPD 5, 38473872, 2005 Coagulation of nanoparticles H.-H. Grotheer et al. Title Page Abstract
[The indices of thrombocyte coagulating and fibrinolytic activity in rheumatoid arthritis patients].
Amosova, E N; Poroshenko, M A
Blood coagulation values (thrombocyte count, adhesive-aggregation thrombocytic activity, coagulographic data) were analysed in 90 patients with rheumatoid arthritis (RA). Increase of plasma coagulation activity was observed in all coagulation activity grades. The anticoagulation activity was most pronounced in grade III RA activity. Thrombocytes of RA patients possessed procoagulant properties and lost significantly their fibrinolytic activity most expressed in grade II RA. This increased the thrombophilic tendency of the plasma potential creating favourable conditions for intravascular coagulation and microthrombus formation, resulting in deterioration of the rheological properties of the blood and the course of the rheumatoid synovitis. PMID:1413678
G. H. Darwin
IN your translation of Prof. Mendeléeff's interesting paper on the chemical elements (November 17, p. 94) I see that he attributes the discovery of argon and its congeners to Ramsay. Am I not right in believing that it was Lord Rayleigh who discovered argon, and that it was he who gave that impulse to chemistry which Sir William Ramsay has
Change in blood coagulation indices as a function of the incubation period of plasma in a constant magnetic field. [considering heparin tolerance and recalcification
NASA Technical Reports Server (NTRS)
Yepishina, S. G.
The influence of a constant magnetic field (CMF) with a strength of 250 and 2500 oersteds on the recalcification reaction and the tolerance of plasma to heparin was studied as a function of the exposure time of the plasma to the CMF. The maximum and reliable change in the activation of the coagulatory system of the blood was observed after a 20-hour incubation of the plasma in a CMF. As the exposure time increased, the recalcification reaction changed insigificantly; the difference between the mean arithmetic of the experiment and control values was not statistically reliable. The tolerance of the plasma to heparin as a function of the exposure time to the CMF of the plasma was considerably modified, an was statistically reliable.
Direct solid analysis of powdered tungsten carbide hardmetal precursors by laser-induced argon spark ablation with inductively coupled plasma atomic emission spectrometry
Markéta Holá; Viktor Kanický; Jean-Michel Mermet; Vít?zslav Otruba
The potential of the laser-induced argon spark atomizer (LINA-Spark atomizer) coupled with ICP-AES as a convenient device for direct analysis of WC\\/Co powdered precursors of sintered hardmetals was studied. The samples were presented for the ablation as pressed pellets prepared by mixing with powdered silver binder containing GeO2 as internal standard. The pellets were ablated with the aid of a
Chronic sleep deprivation markedly reduces coagulation factor VII expression
Pinotti, Mirko; Bertolucci, Cristiano; Frigato, Elena; Branchini, Alessio; Cavallari, Nicola; Baba, Kenkichi; Contreras-Alcantara, Susana; Ehlen, J. Christopher; Bernardi, Francesco; Paul, Ketema N.; Tosini, Gianluca
Chronic sleep loss, a common feature of human life in industrialized countries, is associated to cardiovascular disorders. Variations in functional parameters of coagulation might contribute to explain this relationship. By exploiting the mouse model and a specifically designed protocol, we demonstrated that seven days of partial sleep deprivation significantly decreases (?30.5%) the thrombin generation potential in plasma evaluated upon extrinsic (TF/FVIIa pathway) but not intrinsic activation of coagulation. This variation was consistent with a decrease (?49.8%) in the plasma activity levels of factor VII (FVII), the crucial physiologicalal trigger of coagulation, which was even more pronounced at the liver mRNA level (?85.7%). The recovery in normal sleep conditions for three days completely restored thrombin generation and FVII activity in plasma. For the first time, we demonstrate that chronic sleep deprivation on its own reduces, in a reversible manner, the FVII expression levels, thus influencing the TF/FVIIa activation pathway efficiency. PMID:20418241
The plasma scalpel: a new thermal knife.
Glover, J L; Bendick, P J; Link, W J; Plunkett, R J
A new thermal knife, the plasma scalpel, capable of simultaneous division of tissue and coagulation of blood vessels, is described. A high temperature argon gas plasma (unrelated to blood plasma) is created by passing the gas through a direct current arc, ionizing the gas and elevating its temperature to 3000 degrees C. A small plasma cutting jet is formed by a nozzle at the tip of the handpiece. Liver resections and muscle transections performed in a canine model, and full thickness burn excisions in a pig skin model showed effective division of tissue and significantly less blood loss when compared to the steel scalpel. Wound healing studies of histologic comparisons and wound breaking strength were performed for steel, plasma, laser, and electrosurgical scalped incisions in the skin of mice and rats. All thermal knife wounds showed localized tissue damage at the edges of the incision, but the events of healing began at the same time. Compared to the steel scalpel, there was a three to six day delay in the onset of healing, but healing occurred in the normal fashion and all thermal knife wounds reached the same healed breaking strength as the steel scalpel wounds. Clinically, the plasma scalped has been used for 138 procedures in 96 patients. The majority of cases have been transection of muscle, hepatic resection or debridement, or soft tissue debridement. Muscle transection data for the plasma scalped compared to the electrosurgical scalpel has shown virtually no blood loss with a shorter time to hemostasis for the plasma scalpel. The plasma scalpel has proved to be an effective thermal knife, capable of simultaneous division and coagulation. Further development work and proof of its efficacy in the clinical setting are necessary to establish the plasma scalpel and adequately demonstrate its proper role in surgery. PMID:7109809
Tissue gas and blood analyses of human subjects breathing 80% argon and 20% oxygen
NASA Technical Reports Server (NTRS)
Horrigan, D. J.; Wells, C. H.; Guest, M. M.; Hart, G. B.; Goodpasture, J. E.
Eight human volunteers, individually studied in a hyperbaric chamber, breathed: (1) air at 1 ATA; (2) 80% argon and 20% oxygen at 1 ATA for 30 min; (3) air at 1 ATA for 30 min; (4) 100% O2 at 1 ATA for 30 min; (5) air at 1 ATA for 30 min; (6) 100% O2 at 2 ATA for 60 min; and (7) 80% argon and 20% oxygen at 1 ATA for 30 min. Oxygen, carbon dioxide, nitrogen, and argon tensions were measured in muscle and subcutaneous tissue by mass spectroscopic analyses. Venous blood obtained at regular intervals was analyzed for coagulation and fibrinolytic factors. Inert gas narcosis was not observed. After breathing argon for 30 min, muscle argon tensions were almost three times the subcutaneous tensions. Argon wash-in mirrored nitrogen wash-out. Argon wash-in and wash-out had no effect on tissue PO2 or PCO2. Coagulation and fibrinolytic changes usually associated with vascular bubbles were absent.
Numerical Modeling of Plasmas in which Nanoparticles Nucleate and Grow
NASA Astrophysics Data System (ADS)
Agarwal, Pulkit
Dusty plasmas refer to a broad category of plasmas. Plasmas such as argon-silane plasmas in which particles nucleate and grow are widely used in semiconductor processing and nanoparticle manufacturing. In such dusty plasmas, the plasma and the dust particles are strongly coupled to each other. This means that the presence of dust particles significantly affects the plasma properties and vice versa. Therefore such plasmas are highly complex and they involve several interesting phenomena like nucleation, growth, coagulation, charging and transport. Dusty plasma afterglow is equally complex and important. Especially, residual charge on dust particles carries special significance in several industrial and laboratory situations and it has not been well understood. A 1D numerical model was developed of a low-pressure capacitively-coupled plasma in which nanoparticles nucleate and grow. Polydispersity of particle size distributions can be important in such plasmas. Sectional method, which is well known in aerosol literature, was used to model the evolving particle size and charge distribution. The numerical model is transient and one-dimensional and self consistently accounts for nucleation, growth, coagulation, charging and transport of dust particles and their effect on plasma properties. Nucleation and surface growth rates were treated as input parameters. Results were presented in terms of particle size and charge distribution with an emphasis on importance of polydispersity in particle growth and dynamics. Results of numerical model were compared with experimental measurements of light scattering and light emission from plasma. Reasonable qualitative agreement was found with some discrepancies. Pulsed dusty plasma can be important for controlling particle production and/or unwanted particle deposition. In this case, it is important to understand the behavior of the particle cloud during the afterglow following plasma turn-off. Numerical model was modified to self consistently simulate the dynamics and charging of particles during afterglow. It was found that dusty plasma afterglow is dominated by different time scales for electron and ion dynamics. Particle size and charge distribution changes significantly during the afterglow. Finally, a simplified chemistry model was included in dusty plasma numerical model to simulate the dynamics of argon-silane dusty plasma. The chemistry model treats silane dissociation and reactions of silicon hydrides containing up to two silicon atoms. The nucleation rate is equated to rate of formation of anions containing two Si atoms, and a heterogeneous reaction model is used to model particle surface growth. Evolution of particle size and concentration is explained and the importance of variable surface growth rate and nucleation rate is discussed.
Argon microplasma diagnostics by diode laser absorption
NASA Astrophysics Data System (ADS)
Miura, Naoto; Xue, Jun; Hopwood, Jeffrey
Argon kinetic gas temperature and line integrated resonance state (1s4) density in argon microplasma at 1-760 Torr were estimated by diode laser absorption. A 900 MHz microstrip split ring resonator (MSRR) was used as the microplasma generator. An argon atomic transition at 810.4 nm (1s4-2p7) was chosen as the absorption line. The wavelength of a single-mode laser diode was tuned by changing the diode case temperature. The absorption line was scanned by modulating the laser driving current. The laser output was collimated and passed through a 0.5 mm hole drilled between the MSRR electrodes where the microplasma was sustained. The absorption profile was fit with a Voigt function. The gas temperature was estimated from the broadening, and the line integrated density of the argon resonance state (1s4) was obtained from the integral of the absorption profile. The line integrated densities of argon 1s4 were 1.7x10^15 m-3 m at 1 Torr and 1.4x10^15 m-3 m at 760 Torr with 1W of input power. The visually observed length of plasma decreased from 1 cm at 1 Torr to a few hundred microns at 760 Torr. The measured gas temperature increased from 350 K at 1 Torr to 750 K at 760 Torr. The microplasma was also simulated using a fluid model, which will be compared with experimental measurements.
Biomarkers of inflammation, coagulation and fibrinolysis predict mortality in acute lung injury
Dana McClintock; Hanjing Zhuo; Nancy Wickersham; Michael A Matthay; Lorraine B Ware
BACKGROUND: Acute lung injury (ALI) is a major cause of acute respiratory failure with high mortality despite lung-protective ventilation. Prior work has shown disordered inflammation and coagulation in ALI, with strong correlations between biomarker abnormalities and worse clinical outcomes. We measured plasma markers of inflammation, coagulation and fibrinolysis simultaneously to assess whether these markers remain predictive in the era of
Coagulation-time determination with automatic multivariable analysis, by use of a miniature centrifugal fast analyzer
W. D. Bostick; M. L. Bauer; J. M. Morton; C. A. Burtis
Use of a miniature Centrifugal Fast Analyzer for the parallel photometric monitoring of the coagulation process is shown to have a number of advantages. These include a choice of optical modes, virtually simultaneous initiation and observation of the coagulation process for a number of patient-plasma samples and an on-board control sample, small sample and reagent volume requirements, and automatic determination
Arsenic removal by coagulation
Scott, K.N.; Green, J.F.; Do, H.D.; McLean, S.J. [Metropolitan Water District of Southern California, La Verne, CA (United States)
This study evaluated the removal of naturally occurring arsenic in a full-scale (106-mgd) conventional treatment plant. When the source water was treated with 3--10 mg/L of ferric chloride or 6, 10, or 20 mg/L of alum, arsenic removal was 81--96% (ferric chloride) and 23--71% (alum). Metal concentrations in the sludge produced during this study were below the state`s current hazardous waste levels at all coagulant dosages. No operational difficulties were encountered.
Lunar exospheric argon modeling
NASA Astrophysics Data System (ADS)
Grava, Cesare; Chaufray, J.-Y.; Retherford, K. D.; Gladstone, G. R.; Greathouse, T. K.; Hurley, D. M.; Hodges, R. R.; Bayless, A. J.; Cook, J. C.; Stern, S. A.
Argon is one of the few known constituents of the lunar exosphere. The surface-based mass spectrometer Lunar Atmosphere Composition Experiment (LACE) deployed during the Apollo 17 mission first detected argon, and its study is among the subjects of the Lunar Reconnaissance Orbiter (LRO) Lyman Alpha Mapping Project (LAMP) and Lunar Atmospheric and Dust Environment Explorer (LADEE) mission investigations. We performed a detailed Monte Carlo simulation of neutral atomic argon that we use to better understand its transport and storage across the lunar surface. We took into account several loss processes: ionization by solar photons, charge-exchange with solar protons, and cold trapping as computed by recent LRO/Lunar Orbiter Laser Altimeter (LOLA) mapping of Permanently Shaded Regions (PSRs). Recycling of photo-ions and solar radiation acceleration are also considered. We report that (i) contrary to previous assumptions, charge exchange is a loss process as efficient as photo-ionization, (ii) the PSR cold-trapping flux is comparable to the ionization flux (photo-ionization and charge-exchange), and (iii) solar radiation pressure has negligible effect on the argon density, as expected. We determine that the release of 2.6 × 1028 atoms on top of a pre-existing argon exosphere is required to explain the maximum amount of argon measured by LACE. The total number of atoms (1.0 × 1029) corresponds to ?6700 kg of argon, 30% of which (?1900 kg) may be stored in the cold traps after 120 days in the absence of space weathering processes. The required population is consistent with the amount of argon that can be released during a High Frequency Teleseismic (HFT) Event, i.e. a big, rare and localized moonquake, although we show that LACE could not distinguish between a localized and a global event. The density of argon measured at the time of LACE appears to have originated from no less than four such episodic events. Finally, we show that the extent of the PSRs that trap argon, 0.007% of the total lunar surface, is consistent with the presence of adsorbed water in such PSRs.
How Is Disseminated Intravascular Coagulation Treated?
... the NHLBI on Twitter. How Is Disseminated Intravascular Coagulation Treated? Treatment for disseminated intravascular coagulation (DIC) depends ... and treat the underlying cause. Acute Disseminated Intravascular Coagulation People who have acute DIC may have severe ...
The Continuous Coagulation Equation with Multiple Fragmentation
Magdeburg, Universität
The Continuous Coagulation Equation with Multiple Fragmentation Ankik Kumar Giri , Jitendra Kumar of solutions to the continuous coagulation equation with multiple fragmentation whenever the kernels satisfy approximating equations. The question of uniqueness is also considered. Keywords: Particles; Coagulation
21 CFR 864.5400 - Coagulation instrument.
Code of Federal Regulations, 2014 CFR
...2014-04-01 2014-04-01 false Coagulation instrument. 864.5400 Section 864...Semi-Automated Hematology Devices § 864.5400 Coagulation instrument. (a) Identification. A coagulation instrument is an automated or...
21 CFR 864.5400 - Coagulation instrument.
Code of Federal Regulations, 2013 CFR
...2013-04-01 2013-04-01 false Coagulation instrument. 864.5400 Section 864...Semi-Automated Hematology Devices § 864.5400 Coagulation instrument. (a) Identification. A coagulation instrument is an automated or...
21 CFR 864.5400 - Coagulation instrument.
Code of Federal Regulations, 2011 CFR
...2011-04-01 2011-04-01 false Coagulation instrument. 864.5400 Section 864...Semi-Automated Hematology Devices § 864.5400 Coagulation instrument. (a) Identification. A coagulation instrument is an automated or...
21 CFR 864.5400 - Coagulation instrument.
Code of Federal Regulations, 2012 CFR
...2012-04-01 2012-04-01 false Coagulation instrument. 864.5400 Section 864...Semi-Automated Hematology Devices § 864.5400 Coagulation instrument. (a) Identification. A coagulation instrument is an automated or...
21 CFR 864.5400 - Coagulation instrument.
Code of Federal Regulations, 2010 CFR
...2010-04-01 2010-04-01 false Coagulation instrument. 864.5400 Section 864...Semi-Automated Hematology Devices § 864.5400 Coagulation instrument. (a) Identification. A coagulation instrument is an automated or...
[An experimental study of the coagulating properties of a laser beam applied to fix titanium prostheses of auditory ossicles with the use of platelet-rich plasma].
Semenov, V F; Semenov, F V
The displacement of prostheses of auditory ossicles at the concluding stage of surgery and in the early postoperative period is one of the factors influencing the functional outcome of stapedoplasty. The objective of the present experimental study was to estimate the effectiveness of the use of platelet-rich plasma as an alloy for the laser welding in order to improve fixation of titanium prostheses employed in ossiculoplastic surgery. The results of a series of experiments undertaken to assess the possibility of stabilization of titanium prostheses in the desired position with the help of laser welding indicate that this technique with the use of platelet-rich plasma as an alloy may be a reliable method for the fixation of the reconstructed chain of ossicles in the desired position. PMID:24300758
Roles of argon seeding in energy confinement and pedestal structure in JT-60U
NASA Astrophysics Data System (ADS)
Urano, H.; Nakata, M.; Aiba, N.; Kubo, H.; Honda, M.; Hayashi, N.; Yoshida, M.; Kamada, Y.; the JT-60 Team
The mechanism of improving energy confinement with argon seeding at high density has been investigated in JT-60U. Better confinement is sustained at high density by argon seeding accompanied by higher core and pedestal temperatures. The electron density profiles become flatter with increasing density in conventional H-mode plasmas, whereas peaked density profiles are maintained with argon seeding. Density peaking and dilution effects lower the pedestal density at a given averaged density. The pedestal density in the argon seeded plasmas, which is lower than that in plasmas with deuterium puff, enables the pedestal temperature to be higher, whereas the increase in the pedestal pressure with argon seeding is small. High pedestal temperature is a boundary condition for high core temperature through profile stiffness, which leads to better confinement with argon seeding. The density peaking is a key factor of sustaining better confinement in argon seeded H-mode plasmas. The radiative loss power density is predominantly enhanced in the edge region by argon puff. The role of argon seeding in the pedestal characteristics has also been examined. The pedestal width becomes larger continuously with edge collisionality, but is nearly independent of the presence of argon seeding.
Frequency Matching Effects on Characteristics of Bulk Plasmas and Sheaths for Dual-Frequency Capacitively Coupled Argon Discharges: One-Dimensional Fluid Simulation
Shuai Wang; Xiang Xu; Yuanhong Song; Younian Wang
A one-dimensional fluid model is proposed to simulate the dual-frequency capacitively coupled plasma for Ar discharges. The influences of the low frequency on the plasma density, electron temperature, sheath voltage drop, and ion energy distribution at the powered electrode are investigated. The decoupling effect of the two radio-frequency sources on the plasma parameters, especially in the sheath region, is discussed
Coagulation defects resulting from ambient temperature-induced hypothermia.
Staab, D B; Sorensen, V J; Fath, J J; Raman, S B; Horst, H M; Obeid, F N
Ambient temperature-induced hypothermia noted in trauma patients is frequently accompanied by a bleeding diathesis despite "laboratory normal" coagulation values. To document this impression, the following experiment was conducted. Coagulation studies and platelet function studies were performed in ten minipigs during induced whole body hypothermia (40 degrees C to 34 degrees C) and rewarming. Cooling was achieved in 2 to 3 hours and rewarming took 4 to 5 hours. In addition, similar coagulation and platelet function studies were conducted on plasma samples from the same animals that were cooled and then rewarmed in a water bath. Platelet counts and function as measured by Sonoclot analysis and aggregation did not decrease significantly with hypothermia in either model. Plasma cooled in a water bath demonstrated abnormal PT and aPTT (p < 0.001). Whole body hypothermia demonstrated abnormal bleeding time and PT (p < 0.001). Ambient temperature-induced hypothermia produced significant coagulation defects in a porcine model. Some of the coagulation defects were most pronounced during rewarming. PMID:8189462
Spectroscopic characterization of femtosecond laser filament in argon gas
Liu, W.; Bernhardt, J.; Theberge, F.; Chin, S. L.; Chateauneuf, M.; Dubois, J. [Institute of Modern Optics, Nankai University, Key Laboratory of Opto-electronic Information Science and Technology, Education Ministry of China, Tianjin 300071 (China); Centre d'Optique, Photonique et Laser (COPL) and Departement de physique, de genie physique et d'optique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada); Defence Research and Development Canada--Valcartier, 2459 Pie-XI Blvd. North, Quebec, Quebec, G3J 1X5 Canada (Canada)
We report a spectroscopic approach to measure the plasma density and electron temperature inside a filament created by an intense femtosecond laser pulse in atmospheric pressure argon gas. The technique relies on the proportionality between the Stark broadened argon fluorescence line width due to electron impact and the plasma density, while the electron temperature is determined from the well known Boltzmann plot. The obtained maximum plasma density is about 5.5x10{sup 16} cm{sup -3}, and the electron temperature is about 5800 K. Our method provides a promising and convenient way to characterize the filament for further understanding the fundamental physics and potential applications of filamentation.
Construction and operation of an argon \\/krypton\\/ ion laser
I. Gutu; I. Ivanov; R. Medianu; C. Georgescu
Argon (krypton) laser experiments were performed in a segmented graphite plasma tube. The plasma tube operated either in the 'open-flow' or 'close-mode'. Technological details of several laser components are shown. The efficiency of internal gas recirculation and the effect of magnetic field intensity, discharge current, and mirror transmittance on output power were investigated. Photographs of the optical radiation mode pattern
Enzymic Milk Coagulation: Role of Equations Involving Coagulation Time and Curd Firmness in Describing Coagulation1
D. J. McMahon; G. H. Richardson; R. J. Brown
Digitized curd firmness data were fitted to an exponential equation by a nonlinear, least squares regression com- puter program. Solutions were obtained for actual coagulation time, curd firming rate, and theoretical maximum firmness. Actual coagulation time occurred before an increase in firmness was detectable and coincided with the inflection point of apparent absorbance changes of co- agulating milk. Only the
Vella, E.
The liquid argon calorimeter (LAC) of the SLD detector is a parallel plate -- liquid argon sampling calorimeter, used to measure particle energies in Z[sup 0] decays at the Stanford Linear Collider. The LAC module design is based on a unique projective tower structure, in which lead plates and segmented lead tiles serve both as absorbers and electrodes. The LAC front end electronics incorporates several novel features, including extensive multiplexing and optical fiber readout, which take advantage of the low SLC beam crossing frequency. The operational performance of the LAC during the recently completed SLD physics run (which recorded over 10,000 Z[sup 0] events) is discussed.
Vella, E.; SLD Collaboration
The liquid argon calorimeter (LAC) of the SLD detector is a parallel plate -- liquid argon sampling calorimeter, used to measure particle energies in Z{sup 0} decays at the Stanford Linear Collider. The LAC module design is based on a unique projective tower structure, in which lead plates and segmented lead tiles serve both as absorbers and electrodes. The LAC front end electronics incorporates several novel features, including extensive multiplexing and optical fiber readout, which take advantage of the low SLC beam crossing frequency. The operational performance of the LAC during the recently completed SLD physics run (which recorded over 10,000 Z{sup 0} events) is discussed.
Cerenius, Lage; Söderhäll, Kenneth
In most animals there is a need to quickly prevent the loss of blood or equivalent fluids through inflicted injuries. In invertebrates with an open circulatory system (and sometimes a hydroskeleton as well) these losses may otherwise soon be fatal. Also, there is a need to prevent microbes that have gained access to the body through the wound from disseminating throughout the open circulatory system. Therefore, many invertebrates possess a coagulation system to prevent such accidents from having too serious consequences. In this review we discuss recent developments in a few animals - mainly arthropods - where more detailed data are available. It is likely, however, that corresponding systems are present in most phyla, but this is still unchartered territory. PMID:21051883
Understanding Coagulation Disorders
NSDL National Science Digital Library
Braun, Mark
This tutorial is designed to aid medical students at all levels understand the laboratory diagnosis of disorders of coagulation. It includes introductory material on the basic laboratory tests, their general application and pitfalls in interpretation. The introduction is followed by a series of short clinical vignettes illustrating a variety of clotting disorders. QuickTime movie player and Java script runtime plug-in scripts are required for some pages. The tutorial concludes with a short self-help quiz covering the major points developed. The plug-ins noted above are available free at the following sites: http://www.apple.com/quicktime/download/win.html and http://www.sun.com/ Questions should be directed to Dr. Mark Braun; email@example.com: false
Microfluidics and Coagulation Biology
Colace, Thomas V.; Tormoen, Garth W.
The study of blood ex vivo can occur in closed or open systems, with or without flow. Microfluidic devices facilitate measurements of platelet function, coagulation biology, cellular biorheology, adhesion dynamics, pharmacology, and clinical diagnostics. An experimental session can accommodate 100s to 1000s of unique clotting events. Using microfluidics, thrombotic events can be studied on defined surfaces of biopolymers, matrix proteins, and tissue factor under constant flow rate or constant pressure drop conditions. Distinct shear rates can be created on a device with a single perfusion pump. Microfluidic devices facilitated the determination of intraluminal thrombus permeability and the discovery that platelet contractility can be activated by a sudden decrease in flow. Microfluidics are ideal for multicolor imaging of platelets, fibrin, and phosphatidylserine and provide a human blood analog to the mouse injury models. Overall, microfluidic advances offer many opportunities for research, drug testing under relevant hemodynamic conditions, and clinical diagnostics. PMID:23642241
Thermophysical properties of argon
Jaques, A.
The entire report consists of tables of thermodynamic properties (including sound velocity, thermal conductivity and diffusivity, Prandtl number, density) of argon at 86 to 400/degree/K, in the form of isobars over 0.9 to 100 bars. (DLC)
NASA Astrophysics Data System (ADS)
Michalski, Wojciech; Pospiech, Lucyna; Jankowska-Kuc, Malgorzata
Up to now, among different kinds of lasers an argon laser is mostly used for otosclerosis. Exposure conditions at use of the laser beam are still not well defined. In order to achieve the optimum conditions a series of experiments has been made. Obtained results are presented in this paper.
Argon frost continuous cryopump for fusion applications
Foster, C.A.; McCurdy, H.C.
A cryopumping system based on the snail continuous cryopump concept is being developed for fusion applications under a DOE SBIR grant. The primary pump is a liquid helium cooled compound pump designed to continuously pump and fractionate deuterium/tritium and helium. The D/T pumping stage is a 500 mm bore cryocondensation pump with a nominal pumping speed of 45,000 L/s. It will be continuously regenerated by a snail regeneration by head every 12 minutes. Continuous regeneration will dramatically reduce the vulnerable tritium inventory in a fusion reactor. Operating at an inlet pressure of 1 millitorr, eight of these pumps could pump the projected D/T flow in the ITER CDA design while reducing the inventory of tritium in the pumping system from 630 to 43 grams. The helium fraction will be pumped in a compound argon frost stage. This stage will also operate continuously with a snail regeneration head. In addition the argon spray head will be enclosed inside the snail, thereby removing gaseous argon from the process chamber. Since the cryocondensation stage will intercept over 90% of the D/T/H steam, a purified stream from this stage could be directly reinjected into the plasma as gas or pellets, thereby bypassing the isotope separation system and further simplifying the fuel cycle. Experiments were undertaken in Phase I which demonstrated continuous cryosorption pumping of hydrogen on CO{sub 2} and argon frosts. The pumping system and its relevance to fusion reactor pumping will be discussed.
Coagulation Factors in Controlling Traumatic Bleeds
Pillow, Jonathan
Coagulation Factors in Controlling Traumatic Bleeds: FFP, PCC, or Lucky Sevens? Rose Sohraby, Pharm IV. Mechanisms of blood coagulation1,5 a. Blood coagulation cascade (SEE APPENDIX B) #12;R. Sohraby 3 coagulation activates FIX and FX i. Tissue factor pathway inhibitor (TFPI): inhibits catalytic action of TF
Coagulation with limited aggregations Jean Bertoin
Boyer, Edmond
Coagulation with limited aggregations Jean Bertoin Abstract. Smoluchowski's coagulation equations. Primary 82C23; Secondary 60J80. Keywords. Smoluchowski coagulation equation, random configuration model this particle takes part to a coagulation event. The effect is that the total number of aggregations involving
Cosmic dust synthesis by accretion and coagulation
NASA Technical Reports Server (NTRS)
Praburam, G.; Goree, J.
The morphology of grains grown by accretion and coagulation is revaled by a new laboratory method of synthesizing cosmic dust analogs. Submicron carbon particles, grown by accretion of carbon atoms from a gas, have a spherical shape with a cauliflower-like surface and an internal micro-structure of radial columns. This shape is probably common for grains grown by accretion at a temperature well below the melting point. Coagulated grains, consisting of spheres that collided to form irregular strings, were also synthesized. Another shape we produced had a bumpy non- spherical morphology, like an interplanetary particle collected in the terrestrial stratosphere. Besides these isolated grains, large spongy aggregates of nanometer-size particles were also found for various experimental conditions. Grains were synthesized using ions to sputter a solid target, producing an atomic vapor at a low temperature. The ions were provided by a plasma, which also provided electrostatic levitation of the grains during their growth. The temporal development of grain growth was studied by extinguishing the plasma after various intervals.
Application of an argon-nitrogen inductively-coupled radiofrequency plasma (ICP) to the analysis of geological and related materials for their rare earth contents
NASA Astrophysics Data System (ADS)
Brenner, I. B.; Watson, A. E.; Steele, T. W.; Jones, E. A.; Goncalves, M.
An account is given of the development of a procedure for the determination of the rare earth (RE) elements in a large variety of geological materials employing a medium power argon-nitrogen ICP coupled with a 3.4m Ebert spectrograph. The effects of the carrier and intermediate gas flow rates, height of observation and power on RE spectral line intensities have been studied. The line-to-background ratio of the RE analyte was found to increase with observation height and passed through a maximum at 12-14 mm above the top of the work coil. The method eventually developed allows the direct determination of the lanthanides and yttrium at the 50-200 ?g g -1 levels using a single solution prepared by fusing 0.2-1 g samples with Na 2O 2 or LiBO 2 and dissolving the melt in 4-10% (v/v) HNO 3, or by treating the samples with HF-HClO 4-HNO 3 mixtures. For lower contents of the RE elements, they can be separated from matrix concomitants by ion exchange employing AG50W-X8 resin. A large variety of silicate and phosphate reference materials was analysed using scandium as the internal standard. The relative standard deviations vary from about 1.5-15%. No matrix effects were observed despite the large compositional variation of the samples analysed.
Influence of argon plasma on the deposition of Al2O3 film onto the PET surfaces by atomic layer deposition.
Edy, Riyanto; Huang, Xiaojiang; Guo, Ying; Zhang, Jing; Shi, Jianjun
In this paper, polyethyleneterephthalate (PET) films with and without plasma pretreatment were modified by atomic layer deposition (ALD) and plasma-assisted atomic layer deposition (PA-ALD). It demonstrates that the Al2O3 films are successfully deposited onto the surface of PET films. The cracks formed on the deposited Al2O3 films in the ALD, plasma pretreated ALD, and PA-ALD were attributed to the energetic ion bombardment in plasmas. The surface wettability in terms of water contact angle shows that the deposited Al2O3 layer can enhance the wetting property of modified PET surface. Further characterizations of the Al2O3 films suggest that the elevated density of hydroxyl -OH group improve the initial growth of ALD deposition. Chemical composition of the Al2O3-coated PET film was characterized by X-ray photoelectron spectroscopy, which shows that the content of C 1s reduces with the growing of O 1s in the Al2O3-coated PET films, and the introduction of plasma in the ALD process helps the normal growth of Al2O3 on PET in PA-ALD. PMID:23413804
The removal of trihalomethane precursors by coagulation was studied with low turbidity, low alkalinity waters containing high levels of aquatic humic matter. Jar tests were conducted with synthetic and natural waters using alum, high-molecular-weight polymers, cationic polymers, ...
Katharina Lodders
The solar argon abundance cannot be directly derived by spectroscopic observations of the solar photosphere. The solar Ar abundance is evaluated from solar wind measurements, nucleosynthetic arguments, observations of B stars, HII regions, planetary nebulae, and noble gas abundances measured in Jupiter's atmosphere. These data lead to a recommended argon abundance of N(Ar) = 91,200(+/-)23,700 (on a scale where Si = 10^6 atoms). The recommended abundance for the solar photosphere (on a scale where log N(H) = 12) is A(Ar)photo = 6.50(+/-)0.10, and taking element settling into account, the solar system (protosolar) abundance is A(Ar)solsys = 6.57(+/-)0.10.
Isentropic Compression of Argon
H. Oona; J.C. Solem; L.R. Veeser, C.A. Ekdahl; P.J. Rodriquez; S.M. Younger; W. Lewis; W.D. Turley
We are studying the transition of argon from an insulator to a conductor by compressing the frozen gas isentropically to pressures at which neighboring atomic orbitals overlap sufficiently to allow some electron motion between atoms. Argon and the other rare gases have closed electron shells and therefore remain montomic, even when they solidify. Their simple structure makes it likely that any measured change in conductivity is due to changes in the atomic structure, not in molecular configuration. As the crystal is compressed the band gap closes, allowing increased conductivity. We have begun research to determine the conductivity at high pressures, and it is our intention to determine the compression at which the crystal becomes a metal.
Effects of argon and oxygen flow rate on water vapor barrier properties of silicon oxide coatings deposited on polyethylene terephthalate by plasma enhanced chemical vapor deposition
Sung-Ryong Kim; Moinul Haque Choudhury; Won-Ho Kim; Gon-Ho Kim
Plasma polymer coatings were deposited from hexamethyldisiloxane on polyethylene terephthalate (PET) substrates while varying the operating conditions, such as the Ar and O2 flow rates, at a fixed radio frequency power of 300W. The water vapor transmission rate (WVTR) of the untreated PET was 54.56g\\/m2\\/day and was decreased after depositing the silicon oxide (SiOx) coatings. The minimum WVTR, 0.47g\\/m2\\/day, was
Argon Purification Reference and Recommendation
Wu, J.; /Fermilab
This engineering note is a reference for future consideration on the purification of argon. The original concern was for the possibility of argon contamination from components in the cryostats over long-term storage. An argon purification system could also be useful for purifying the contents of the argon dewar. The general conclusion is that most of the systems researched are too expensive at this time, but the recommended choice would be Centorr Furnaces. There were three basic types of purification systems which were to be considered. The first was the molecular sieve. This method would have been the preferred one, because it was claimed that it could purify liquid argon, removing liquid oxygen from the argon. However, none of the commercial companies researched provided this type of purification for use with liquid argon. Most companies said that this type of purification was impossible, and tests at IB-4 confirmed this. The second system contained a copper oxide to remove gaseous oxygen from argon gas. The disadvantage of this system wass that the argon had to be heated to a gas, and then cooled back down to liquid. The third system was similar to the second, except that it used tungsten or another material like titanium. This system also needed to heat the argon to gas, however the advantage of this system was that it supposedly removed all contaminants, that is, everything except for inert gases. Of the three systems, the third is the type manufactured by Centorr Furnaces, which uses a titanium charge.
Determination of argon in sputtered silicon films by energy-dispersive x-ray fluorescence spectrometry
Dennis J. Kalnicky; T. D. Moustakas
Hydrogenated amorphous silicon can be prepared by glow discharge decomposition of silane or by reactive sputtering in an argon + hydrogen plasma. The sputtered films contain some percentage of argon incorporated in them and its role in determining the physical properties of these materials is of interest. This paper describes energy-dispersive x-ray fluorescence (EDXRF) methods which were developed to characterize
Method to measure the electric field vector in an argon glow discharge using laser polarization spectroscopy
V. P. Gavrilenko; H. J. Kim; T. Ikutake; J. B. Kim; M. D. Bowden; K. Muraoka
A method for measurement of the direction of the electric field in a glow discharge is reported. This method uses the dependence of the electronic excitation spectrum of argon atoms on the polarization of the laser radiation. In this research, laser radiation was used to excite argon atoms in a plasma from the 4s [32]2 metastable level to Rydberg levels,
Evaluation of continuous hydride generation combined with helium and argon microwave induced plasmas using a surfatron for atomic emission spectrometric determination of arsenic, antimony and selenium
NASA Astrophysics Data System (ADS)
Yang, Jinfu; Schickling, C.; Broekaert, J. A. C.; Tschöpel, P.; Tölg, G.
The direct coupling of continuous hydride generation with both Ar and He microwave induced plasmas (MIP) sustained in a surfatron has been optimized for the simultaneous determination of arsenic, antimony and selenium with atomic emission spectrometry. While a discharge tube of quartz was found suitable for the Ar plasma, the use of an Al 2O 3 tube led to improved performance of the He plasma. The He MIP was found to be less tolerant to the introduction of hydrogen than the Ar MIP, and correspondingly the hydride generation should be operated at a lower flow rate of 0.5% NaBH 4 solution. The introduction of the H 2O vapour produced during hydride generation into both discharges was found to greatly decrease the sensitivities and to degrade the measurement precision. It could be effectively removed with trapping by concentrated H 2SO 4. The detection limits (3?) for As, Sb and Se are 1, 0.4 and 1 ng ml -1 with the Ar MIP, and 2, 0.3 and 6 ng ml -1 with the He MIP, respectively. The calibration curves are linear over three decades of concentration. The mutual interferences from As(III), Sb(III), Se(IV), Bi(III) and Sn(IV) were found to be negligible at interferent concentrations below 1 ?g ml -1 and in most cases the tolerable interferent concentrations are up to 20 ?g ml -1. The proposed method has been applied to the determination of As, Sb and Se in tea samples at ?g g -1 levels.
Endotoxin Induced Disseminated Intravascular Coagulation in Cattle
Thomson, G. W.; McSherry, B. J.; Valli, V. E. O.
Endotoxin administered intravenously to a group of four calves resulted in disseminated intravascular coagulation. A sublethal dose of piromen, a commercially available Pseudomonas spp endotoxin, was used. Serial measurements of total plasma fibrinogen, soluble fibrin levels, ethanol gelation tests, protamine sulfate tests, fibrinogen-fibrin-related antigen (FR-antigen) and prothrombin and thrombin times were done. Initial depression of plasma fibrinogen with a nadir of about 40% of pre-endotoxin levels at eight to 11 hours post-endotoxin (+8 to +11 hours) followed by an overcompensation to 180% at +60 to +108 hours was shown. Soluble fibrin was demonstrated in plasma from +2 to +22 hours with a peak of 100-114 mg/100 ml at +4 to +9 hours. Positive plasma ethanol gelation and protamine sulfate tests, as well as the presence of serum FR-antigen, occurred consistently following endotoxin administration. Significant increases in prothrombin times (PT) from +4 to +40 hours and in thrombin times (TT) from +4 to +16 hours were demonstrated. The peak increase of PT at +8 to +10 hours was 180%. The peak increase of TT at +6 to +9 hours was 260-290%. ImagesFig. 1.Fig. 2.Fig. 3.Fig. 4. PMID:4279765
Dielectronic recombination on heliumlike argon
Ali, R.; Bhalla, C.P.; Cocke, C.L.; Stockli, M. (J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, Kansas 66506 (USA))
We have used the electron-energy dependence of yields of heliumlike and lithiumlike argon ions from the Kansas State University electron-beam ions source (EBIS) to measure the ratio of the cross section for {Delta} {ital n}=1 dielectronic recombination of heliumlike argon to that for electron ionization of lithiumlike argon. By normalizing to the latter cross section we obtain absolute dielectronic recombination cross sections and find good agreement with theoretical calculations for the lower-energy resonances.
The Argon Geochronology Experiment (AGE)
NASA Technical Reports Server (NTRS)
Swindle, T. D.; Bode, R.; Fennema, A.; Chutjian, A.; MacAskill, J. A.; Darrach, M. R.; Clegg, S. M.; Wiens, R. C.; Cremers, D.
This viewgraph presentation reviews the Argon Geochronology Experiment (AGE). Potassium-Argon dating is shown along with cosmic ray dating exposure. The contents include a flow diagram of the Argon Geochronology Experiment, and schematic diagrams of the mass spectrometer vacuum system, sample manipulation mechanism, mineral heater oven, and the quadrupole ion trap mass spectrometer. The Laser-Induced Breakdown Spectroscopy (LIBS) Operation with elemental abundances is also described.
Numerical analysis of the effect of nitrogen and oxygen admixtures on the chemistry of an argon plasma jet operating at atmospheric pressure
NASA Astrophysics Data System (ADS)
Van Gaens, W.; Iseni, S.; Schmidt-Bleker, A.; Weltmann, K.-D.; Reuter, S.; Bogaerts, A.
In this paper we study the cold atmospheric pressure plasma jet, called kinpen, operating in Ar with different admixture fractions up to 1% pure {{N}2}, {{O}2} and {{N}2} + {{O}2}. Moreover, the device is operating with a gas curtain of dry air. The absolute net production rates of the biologically active ozone ({{O}3}) and nitrogen dioxide (N{{O}2}) species are measured in the far effluent by quantum cascade laser absorption spectroscopy in the mid-infrared. Additionally, a zero-dimensional semi-empirical reaction kinetics model is used to calculate the net production rates of these reactive molecules, which are compared to the experimental data. The latter model is applied throughout the entire plasma jet, starting already within the device itself. Very good qualitative and even quantitative agreement between the calculated and measured data is demonstrated. The numerical model thus yields very useful information about the chemical pathways of both the {{O}3} and the N{{O}2} generation. It is shown that the production of these species can be manipulated by up to one order of magnitude by varying the amount of admixture or the admixture type, since this affects the electron kinetics significantly at these low concentration levels.
Enhanced coagulation for arsenic removal
Cheng, R.C.; Liang, S.; Wang, H.C.; Beuhler, M.D. (Metropolitan Water District of Southern California, La Verne, CA (United States))
The possible use of enhanced coagulation for arsenic removal was examined at the facilities of a California utility in 1992 and 1993. The tests were conducted at bench, pilot, and demonstration scales, with two source waters. Alum and ferric chloride, with cationic polymer, were investigated at various influence arsenic concentrations. The investigators concluded that for the source waters tested, enhanced coagulation could be effective for arsenic removal and that less ferric chloride than alum, on a weight basis, is needed to achieve the same removal.
Thermophysical properties of multi-shock compressed dense argon
Chen, Q. F., E-mail: firstname.lastname@example.com; Zheng, J.; Gu, Y. J.; Chen, Y. L.; Cai, L. C. [National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, P. O. Box 919-102, Mianyang, Sichuan (China)] [National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, P. O. Box 919-102, Mianyang, Sichuan (China); Shen, Z. J. [Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, P. O. Box 8009-26, Beijing 10086 (China)] [Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, P. O. Box 8009-26, Beijing 10086 (China)
In contrast to the single shock compression state that can be obtained directly via experimental measurements, the multi-shock compression states, however, have to be calculated with the aid of theoretical models. In order to determine experimentally the multiple shock states, a diagnostic approach with the Doppler pins system (DPS) and the pyrometer was used to probe multiple shocks in dense argon plasmas. Plasma was generated by a shock reverberation technique. The shock was produced using the flyer plate impact accelerated up to ?6.1 km/s by a two-stage light gas gun and introduced into the plenum argon gas sample, which was pre-compressed from the environmental pressure to about 20 MPa. The time-resolved optical radiation histories were determined using a multi-wavelength channel optical transience radiance pyrometer. Simultaneously, the particle velocity profiles of the LiF window was measured with multi-DPS. The states of multi-shock compression argon plasma were determined from the measured shock velocities combining the particle velocity profiles. We performed the experiments on dense argon plasmas to determine the principal Hugonoit up to 21 GPa, the re-shock pressure up to 73 GPa, and the maximum measure pressure of the fourth shock up to 158 GPa. The results are used to validate the existing self-consistent variational theory model in the partial ionization region and create new theoretical models.
Output power characteristics of the pulsed argon ion laser
T. Cottrell
The output power of pulsed noble gas ion lasers is discussed in terms of dependence on gain, plasma tube length, current density, and excitation mechanisms. Experimental data for some of the strong laser transitions of singly ionized argon in pulsed operation are presented. The resulting power output dependence on current density suggests that two-step excitation plays an important role, particularly
Thermophysical properties of multi-shock compressed dense argon.
Chen, Q F; Zheng, J; Gu, Y J; Chen, Y L; Cai, L C; Shen, Z J
In contrast to the single shock compression state that can be obtained directly via experimental measurements, the multi-shock compression states, however, have to be calculated with the aid of theoretical models. In order to determine experimentally the multiple shock states, a diagnostic approach with the Doppler pins system (DPS) and the pyrometer was used to probe multiple shocks in dense argon plasmas. Plasma was generated by a shock reverberation technique. The shock was produced using the flyer plate impact accelerated up to ?6.1 km/s by a two-stage light gas gun and introduced into the plenum argon gas sample, which was pre-compressed from the environmental pressure to about 20 MPa. The time-resolved optical radiation histories were determined using a multi-wavelength channel optical transience radiance pyrometer. Simultaneously, the particle velocity profiles of the LiF window was measured with multi-DPS. The states of multi-shock compression argon plasma were determined from the measured shock velocities combining the particle velocity profiles. We performed the experiments on dense argon plasmas to determine the principal Hugonoit up to 21 GPa, the re-shock pressure up to 73 GPa, and the maximum measure pressure of the fourth shock up to 158 GPa. The results are used to validate the existing self-consistent variational theory model in the partial ionization region and create new theoretical models. PMID:24559345
Thermophysical properties of multi-shock compressed dense argon
NASA Astrophysics Data System (ADS)
Chen, Q. F.; Zheng, J.; Gu, Y. J.; Chen, Y. L.; Cai, L. C.; Shen, Z. J.
In contrast to the single shock compression state that can be obtained directly via experimental measurements, the multi-shock compression states, however, have to be calculated with the aid of theoretical models. In order to determine experimentally the multiple shock states, a diagnostic approach with the Doppler pins system (DPS) and the pyrometer was used to probe multiple shocks in dense argon plasmas. Plasma was generated by a shock reverberation technique. The shock was produced using the flyer plate impact accelerated up to ˜6.1 km/s by a two-stage light gas gun and introduced into the plenum argon gas sample, which was pre-compressed from the environmental pressure to about 20 MPa. The time-resolved optical radiation histories were determined using a multi-wavelength channel optical transience radiance pyrometer. Simultaneously, the particle velocity profiles of the LiF window was measured with multi-DPS. The states of multi-shock compression argon plasma were determined from the measured shock velocities combining the particle velocity profiles. We performed the experiments on dense argon plasmas to determine the principal Hugonoit up to 21 GPa, the re-shock pressure up to 73 GPa, and the maximum measure pressure of the fourth shock up to 158 GPa. The results are used to validate the existing self-consistent variational theory model in the partial ionization region and create new theoretical models.
Near ultraviolet operation of argon and krypton ion lasers
S. M. Jarrett; G. C. Barker
Several reports on operation of ion lasers on the transitions between states in doubtedly ionized argon and krypton (Ar III and Kr III) leading to oscillation in the near ultraviolet have been given in the last three years (1-3). These reports deal with ultraviolet operation utilizing plasma tubes specifically designed to achieve high current densities. We have experimented with production
Original article Chemical composition and coagulation properties
Paris-Sud XI, Université de
Original article Chemical composition and coagulation properties of Modicana and Holstein cows composition was the same in both breeds. The pH of the Mo milk was lower (0.07), coagulation time and curd coagulation du lait des races bovines Modicana et Holstein. La production, la composition chimique et l
ORIGINAL PAPER Coagulation temperature affects the microstructure
Paris-Sud XI, Université de
ORIGINAL PAPER Coagulation temperature affects the microstructure and composition of full fat # INRA and Springer Science+Business Media B.V. 2011 Abstract An understanding of coagulation and factors of coagulation temperature on the microstructure of gel, curd and cheese samples during the manufacture of full
Filbet, Francis
NUMERICAL SIMULATION OF THE SMOLUCHOWSKI COAGULATION EQUATION FRANCIS FILBET AND PHILIPPE LAURENC2028 Abstract. In this paper, we develop a numerical scheme for the Smoluchowski coagulation equation, which. Smoluchowski coagulation equation, self-similar variables, finite volume method AMS subject classifications. 65
Coagulation-Fragmentation Processes Herbert Amann
Amann, Herbert
Coagulation-Fragmentation Processes Herbert Amann Abstract. We study the well-posedness of coagulation-fragmentation mod- els with di#11;usion for large systems of particles. The continuous processes of this type). In a multitude of situations, namely in the case of thermal coagulation
Mischler, Stéphane
GELATION IN COAGULATION AND FRAGMENTATION MODELS M. Escobedo1 , S. Mischler2,3 and B. Perthame3 to the coagulation-fragmentation model for which gelation is established in some particular cases. Key words: Smoluchowski's coagulation equation, decay rate, gelation, profile at gelling time, Morrey-Campanato norms
Discrete and Continuous Coagulation-Fragmentation Models
Jensen, Max
Discrete and Continuous Coagulation-Fragmentation Models with Diffusion Klemens Fellner DAMTP.04.2011 p. 1/3 #12;Introduction Coagulation-fragmentation models with diffusion evolution of a polymer = j=1 Bi+j i+j,i ci+j - Bi ci. coagulation-fragmentation coefficients ai,j = aj,i 0, i,j 0, (i, j N
Amann, Herbert
COAGULATION-FRAGMENTATION MODELS WITH DIFFUSION Herbert Amann Institute for Mathematics, University of particles, being suspended in a uid, for example, which can di#11;use and coagulate to form clusters that ; (1) where the coagulation term [@ t u] coag is given by [@ t u] coag (y) = 1 2 Z y 0 (y y 0 ; y 0 )u
Coagulation by hydrolysing metal salts
Jinming Duan; John Gregory
Aluminium and iron salts are widely used as coagulants in water and wastewater treatment and in some other applications. They are effective in removing a broad range of impurities from water, including colloidal particles and dissolved organic substances. Their mode of action is generally explained in terms of two distinct mechanisms: charge neutralisation of negatively charged colloids by cationic hydrolysis
Acquired coagulant factor VIII deficiency induced by Bacillus anthracis lethal toxin in mice.
Sun, Der-Shan; Lee, Po-Chien; Kau, Jyh-Hwa; Shih, Yung-Luen; Huang, Hsin-Hsien; Li, Chen-Ru; Lee, Chin-Cheng; Wu, Yu-Ping; Chen, Kuo-Ching; Chang, Hsin-Hou
Mice treated with anthrax lethal toxin (LT) exhibit hemorrhage caused by unknown mechanisms. Moreover, LT treatment in mice induced liver damage. In this study, we hypothesized that a suppressed coagulation function may be associated with liver damage, because the liver is the major producing source of coagulation factors. The hepatic expression of coagulant factors and the survival rates were analyzed after cultured cells or mice were exposed to LT. In agreement with our hypothesis, LT induces cytotoxicity against hepatic cells in vitro. In addition, suppressed expression of coagulation factor VIII (FVIII) in the liver is associated with a prolonged plasma clotting time in LT-treated mice, suggesting a suppressive role of LT in coagulation. Accordingly, we further hypothesized that a loss-of-function approach involving treatments of an anticoagulant should exacerbate LT-induced abnormalities, whereas a gain-of-function approach involving injections of recombinant FVIII to complement the coagulation deficiency should ameliorate the pathogenesis. As expected, a sublethal dose of LT caused mortality in the mice that were non-lethally pretreated with an anticoagulant (warfarin). By contrast, treatments of recombinant FVIII reduced the mortality from a lethal dose of LT in mice. Our results indicated that LT-induced deficiency of FVIII is involved in LT-mediated pathogenesis. Using recombinant FVIII to correct the coagulant defect may enable developing a new strategy to treat anthrax. PMID:25906166
Plasma Characterization of Electronegatively diluted VHF CCP Plasmas
Alex Paterson; Ned Hammond; Shahid Rauf; Ed Barnat; Paul Miller; Greg Hebner
In this study, the plasma characteristics of a VHF capacitively-coupled, 300 mm processing system were investigated. Spatially dependent ion and electron density, as well as electron energy distribution functions, were measured for frequencies between 27 and 170 MHz and for gas mixtures containing argon, SF6 and CF4. In argon plasmas, increasing the frequency above 120 MHz changed the ion and
Coagulation Activation in Diabetes mellitus
J. W. J. Van Wersch; L. W. J. J. M. Westerhuis; W. J. R. R. Venekamp
One hundred and fourty-eight insulin-dependent diabetic patients were available for this study; 56 males and 92 females. For the investigation of coagulation activation we determined activated partial thromboplastin time, thrombin time, and fibrinogen besides fibrin monomers and thrombin-antithrombin III complexes (TAT-III). We assessed large percentages of increased fibrinogen levels but non-significant increases of the mean values in comparison with the
Axial evolution of radial heat flux profiles transmitted by atmospheric pressure nitrogen and argon arcs
NASA Astrophysics Data System (ADS)
Meher, K. C.; Tiwari, N.; Ghorui, S.; Sahasrabudhe, S. N.; Das, A. K.
Axial evolutions of radial heat flux profiles in argon and nitrogen plasma jets from an atmospheric pressure dc non-transferred arc plasma torch are determined using a double calorimetric technique. Results are presented for power levels suitable for the processing of high temperature ceramic oxides, where the heat flux data reported in the literature is rare. Variations of the profile widths and profile maxima are presented as a function of axial distance as well as power. Relatively uniform profile width over prolonged axial distance for nitrogen plasma compared to argon is an important observation which has the potential to offer a much longer dwell time of the injected particles inside the plasma, avoiding the problem of unmelts, especially for ceramics. A comparative study of the heat flux profiles for argon and nitrogen plasma is presented. The obtained results are compared with the data reported in literature.
Coagulant-based emergency water treatment
C. C. Dorea
Emergency water treatment approaches relying on coagulation vary from centralised modular and portable "kits" to "point-of-use" or "household" interventions. Typical coagulation practice in emergencies is reviewed in view of field constraints (e.g. equipment and resources) and contrasted with underlying theory and conventional water treatment procedures. Examples of coagulation in emergencies are also presented based on documented field experiences alongside the
Interactions between alum and organics in coagulation
Chihpin Huang; Hueiling Shiu
The coagulation-sedimentation process, i.e. a major pretreatment for filtration, has the potential to remove organic contaminants. However, interactions between coagulants and organics in the absence of suspended solids have only received limited attention. This study aims to model alum-organics' interactions corresponding to the behavior of organics during coagulation. Two typical organic materials, humic acid and salicylic acid, are investigated. Experimental
[Intravascular coagulation in cirrhotic patients. 6 cases].
Bourreille, J; Hayet, M; Joram, F; Bentot, G
Authors relate six cases of Disseminated Intra-Vascular Coagulation (D.I.V.C.) which occured among cirrhotic patients. They discovered it during and at the end of a systematic study of blood coagulation among hepatic deficient people. On the occasion of this series, authors consider mechanism of D.I.V.C. among cirrhotics. They defined a group of six coagulation tests which seem to them necessary an adequate to fix up diagnosis. PMID:1153281
Effect of fibrinogen on blood coagulation detected by optical coherence tomography
NASA Astrophysics Data System (ADS)
Xu, Xiangqun; Teng, Xiangshuai
Our previous work demonstrated that an optical coherence tomography (OCT) technique and the parameter 1/e light penetration depth (d1/e) were able to characterize the whole blood coagulation process in contrast to existing optical tests that are performed on plasma samples. To evaluate the feasibility of the technique for quantifying the effect of fibrinogen (Fbg) on blood coagulation, a dynamic study of d1/e of blood in various Fbg concentrations was performed in static state. Two groups of blood samples of hematocrit (HCT) in 35, 45, and 55% were reconstituted of red blood cells with: 1) treated plasma with its intrinsic Fbg removed and commercial Fbg added (0–8?g?L?1) and 2) native plasma with commercial Fbg added (0–8?g?L?1). The results revealed a typical behavior due to coagulation induced by calcium ions and the clotting time is Fbg concentration-dependent. The clotting time was decreased by the increasing amount of Fbg in both groups. Besides, the blood of lower HCT with various levels of Fbg took shorter time to coagulate than that of higher HCT. Consequently, the OCT method is a useful and promising tool for the detection of blood-coagulation processes induced with different Fbg levels.
Effect of fibrinogen on blood coagulation detected by optical coherence tomography.
Xu, Xiangqun; Teng, Xiangshuai
Our previous work demonstrated that an optical coherence tomography (OCT) technique and the parameter 1/e light penetration depth (d1/e) were able to characterize the whole blood coagulation process in contrast to existing optical tests that are performed on plasma samples. To evaluate the feasibility of the technique for quantifying the effect of fibrinogen (Fbg) on blood coagulation, a dynamic study of d1/e of blood in various Fbg concentrations was performed in static state. Two groups of blood samples of hematocrit (HCT) in 35, 45, and 55% were reconstituted of red blood cells with: 1) treated plasma with its intrinsic Fbg removed and commercial Fbg added (0-8?g?L(-1)); and 2) native plasma with commercial Fbg added (0-8?g?L(-1)). The results revealed a typical behavior due to coagulation induced by calcium ions and the clotting time is Fbg concentration-dependent. The clotting time was decreased by the increasing amount of Fbg in both groups. Besides, the blood of lower HCT with various levels of Fbg took shorter time to coagulate than that of higher HCT. Consequently, the OCT method is a useful and promising tool for the detection of blood-coagulation processes induced with different Fbg levels. PMID:25955503
Comparison of the coagulation effects on different coagulants in raw water treatment
Ping Xia; Hui Ye; Jun Feng
According to the quality of raw water in water plants, the pollution removal rates of three different coagulants dosage were compared. There search conclusion on coagulation effects of different coagulants. The results showed that the coagulation effect of PACS(B) was best, when the best of its injection was 30mg\\/L, the removal turbidity rate was 94%, the removal color rate was
Measurement method for electric fields based on stark spectroscopy of argon atoms
Gavrilenko; Kim; Ikutake; Kim; Choi; Bowden; Muraoka
We report the development of a method for the measurement of electric fields in glow discharge plasmas, based on Stark spectroscopy of argon atoms. The method is based on laser excitation of transitions in atomic argon. The key feature of the method is that the electric field is determined by matching experimentally obtained absorption spectra to theoretically calculated spectra. The dependence of the positions of energy levels of argon atoms on the strength of the electric field was calculated by solving the Schrodinger equation for the argon atom. Measurements of Stark spectra were made in the sheath region of a glow discharge using laser optogalvanic spectroscopy. The wavelength of the laser radiation was tuned to the transitions 4s-->nf (n=7,8,ellipsis,14) of the argon atom. For n=11, the lower limit for electric field measurements was estimated to be 14 V/mm. PMID:11102076
Coagulation, Diffusion and the Continuous Smoluchowski Equation Mohammad Reza Yaghouti
Goldschmidt, Christina
Coagulation, Diffusion and the Continuous Smoluchowski Equation Mohammad Reza Yaghouti Amirkabir particles are prone to binary coagulation. Smoluchowski's equation comes in two flavours: discrete model of coagulating Brownian particles. (See also [7], [9] and [2] for similar results.) The main
Mischler, Stéphane
CONVERGENCE TO EQUILIBRIUM FOR THE CONTINUOUS COAGULATION-FRAGMENTATION EQUATION Philippe Lauren coagulation-fragmentation equa- tion under the detailed balance condition. We deduce the convergence time convergence to an equilibrium state for solutions to the continuous coagulation
Coagulation, Diffusion and the Continuous Smoluchowski Equation Mohammad Reza Yaghouti
Rezakhanlou, Fraydoun
Coagulation, Diffusion and the Continuous Smoluchowski Equation Mohammad Reza Yaghouti Amirkabir equation is a system of partial differential equations modelling the diffusion and binary coagulation Smoluchowski Equation, Coagulating Brownian Particles. 1 Introduction It is a common practice in statistical
Modelling Genetic Variations with Fragmentation-Coagulation Processes
Rattray, Magnus
Modelling Genetic Variations with Fragmentation-Coagulation Processes Yee Whye Teh, Charles nonparametric models for sequential data called fragmentation-coagulation processes (FCPs). FCPs model a set Bayesian nonparametric models for genetic variations called fragmentation-coagulation processes (FCPs
Coagulation, Fragmentation and Growth Processes in a Size Structured Population.
Mottram, Nigel
Coagulation, Fragmentation and Growth Processes in a Size Structured Population. Jacek Banasiak the effects of cell division and aggregration are incorporated by coupling the coagulation- fragmentation in the literature. Key words. semigroups of operators, semilinear Cauchy problem, coagulation, fragmentation, algal
Two solvable systems of coagulation equations with limited aggregations
Paris-Sud XI, Université de
Two solvable systems of coagulation equations with limited aggregations Jean Bertoin Abstract We are governed by modifications of Smoluchowski's coagulation equations. Applying classical techniques based and point at some connexions with certain known solutions to Smoluchowski's coagulation equations
Ionization behind strong normal shock waves in argon
Kaniel, A.; Igra, O.; Ben-Dor, G.; Mond, M.
The ionization of argon by strong normal shock waves is studied. The conservation equations are solved to yield the plasma behavior behind the shock wave front. Very good agreement is obtained between experimental findings and the present numerical results for the electron number density, plasma density, and degree of ionization, especially at the electron avalanche region of the relaxation zone. The high accuracy of the present numerical solutions in reproducing the electron avalanche is attributed to the use of accurate threshold collision cross sections for excitation of argon by electron collisions. To support this claim it is demonstrated that if different assumptions were used to describe the ionization process, then the computed results would be different only upstream of the electron avalanche region, i.e., it is shown that the proposed model for ionizing shock waves enables a highly accurate reproduction of the electron avalanche but is less accurate in predicting its exact location.
Coagulation activation in diabetes mellitus.
Van Wersch, J W; Westerhuis, L W; Venekamp, W J
One hundred and fourty-eight insulin-dependent diabetic patients were available for this study; 56 males and 92 females. For the investigation of coagulation activation we determined activated partial thromboplastin time, thrombin time, and fibrinogen besides fibrin monomers and thrombin-antithrombin III complexes (TAT-III). We assessed large percentages of increased fibrinogen levels but non-significant increases of the mean values in comparison with the reference group. The values for thrombin time were significantly prolonged, although relatively small percentages were exceeding the reference range. For the activated partial thromboplastin time, the values exceeded the upper reference limit, and the mean values were significantly higher than those of the reference group. Also for the fibrin monomers we obtained often enhanced values, and moreover, the values were significantly higher as compared with the reference subjects. The amount of TAT-III concentrations above the reference range was much smaller than for the fibrin monomers and the TAT-III levels were not significantly enhanced. The results presented here are indicative of coagulation activation in diabetics, as indicated by the fibrin monomers and more or less by the TAT-III levels. Moreover, there could be demonstrated a positive correlation between fibrin monomer levels and HbA1 concentrations. PMID:2289707
Method to measure the electric field vector in an argon glow discharge using laser polarization spectroscopy.
Gavrilenko, V P; Kim, H J; Ikutake, T; Kim, J B; Bowden, M D; Muraoka, K
A method for measurement of the direction of the electric field in a glow discharge is reported. This method uses the dependence of the electronic excitation spectrum of argon atoms on the polarization of the laser radiation. In this research, laser radiation was used to excite argon atoms in a plasma from the 4s [3 / 2](2) metastable level to Rydberg levels, and excitation spectra were measured using laser optogalvanic (LOG) spectroscopy. In addition, LOG spectra of argon atoms interacting with an electric field were calculated by solving the Schrödinger equation. Good agreement was found between experimental and theoretical LOG spectra obtained for different polarizations of the laser radiation. PMID:11308986
Monitoring blood coagulation with magnetoelastic sensors
Libby G Puckett; Gary Barrett; Dimitris Kouzoudis; Craig Grimes; Leonidas G Bachas
The determination of blood coagulation time is an essential part of monitoring therapeutic anticoagulants. Standard methodologies for the measurement of blood clotting time require dedicated personnel and involve blood sampling procedures. A new method based on magnetoelastic sensors has been employed for the monitoring of blood coagulation. The ribbon-like magnetoelastic sensor oscillates at a fundamental frequency, which shifts linearly in
Microwave coagulation therapy for hepatocellular carcinoma
M Sato; Y Watanabe; S Ueda; S Iseki; Y Abe; N Sato; S Kimura; K Okubo; M Onji
BACKGROUND & AIMS: Surgical resection is not always feasible in patients with hepatocellular carcinoma. Microwave coagulation therapy has been used as an alternative to resection, and its efficacy has been evaluated. METHODS: Nineteen patients with unresectable hepatocellular carcinoma underwent microwave coagulation therapy through laparotomy (n = 12), laparoscopy (n = 5), or thoracotomy (n = 2) because of advanced liver
Optical properties of heated air, carbon dioxide, and argon
L. I. Kiselevskii; V. D. Shimanovich
Stable-plasma generators, spectroscopic measuring equipment, and methods for determining the optical properties of an extremely\\u000a heated medium with a given composition have been developed. The spectral coefficients of absorption and emission of heated\\u000a air, carbon dioxide, and argon were studied. A comparison with the data of other theoretical and experimental investigations\\u000a has been performed.
Textile wastewater purification through natural coagulants
NASA Astrophysics Data System (ADS)
Beltrán-Heredia, J.; Sánchez-Martín, J.; Rodríguez-Sánchez, M. T.
A new coagulant obtained through polymerization of Acacia mearnsii de Wild tannin extract has been characterized in the removal of two dangerous dye pollutants: Alizarin Violet 3R and Palatine Fast Black WAN. This coagulant is lab-synthesized according to the etherification of tannins with glycidyltrimethylammonium chloride and formaldehyde and its performance in dye removal in terms of efficiency was high. Reasonably low coagulant dosages (ca. 50 mg L-1) reaches high capacity levels (around 0.8 for Alizarin Violet 3R and 1.6 for Palatine Fast Black WAN mg dye mg-1 of coagulant) and pH and temperature are not extremely affecting variables. The systems coagulant dyes were successfully modeled by applying the Langmuir hypothesis. q max and b parameters were obtained with an adjusted correlation factor ( r 2) above 0.8.
Determination of coagulation time in whole blood containing anticoagulant by piezoelectric quartz crystal sensor
Hsien-Chang Chang; Tzong-Jih Cheng; Tsui-Hsun Wu; Tsun-Mei Lin
A piezoelectric quartz crystal (PQC) system possessing an adequate sensitivity to a slight change of viscosity was previously employed to monitor blood coagulation. Here, the activated partial thromboplastin time (aPTT), clotting time (CT) for platelet poor plasma (PPP), and whole blood were evaluated using PQC system, the results showed a good agreement with the aPTT results measured by optical coagulometer
Genetic polymorphism of the a subunit of human coagulation factor XIII in Japanese
Toshinori Nishigaki; Keiichi Omoto; Takeo Juji
Summary Polymorphism of the A subunit of human coagulation factor XIII was investigated in a total of 561 plasma samples from unrelated adult Japanese using an agarose gel electrophoresis followed by a fluorescent technique for the localization of transglutaminase activity. Three common phenotypes were observed, which corresponded to the types 1, 2-1 and 2 reported by Board (1979) in Australians.
Comparison of a novel polytitanium chloride coagulant with polyaluminium chloride: coagulation performance and floc characteristics.
Zhao, Y X; Phuntsho, S; Gao, B Y; Yang, Y Z; Kim, J-H; Shon, H K
Polymerized inorganic coagulants are increasingly being used in the water supply and wastewater treatment process, yet there is limited research on the development of polytitanium coagulants. The aim of this study is to synthesize polytitanium chloride (PTC) coagulants and investigate their coagulation behavior and floc characteristics for humic acid removal in comparison to polyaluminum chloride (PAC). The PTC samples with different B (molar ratios of OH/Ti) values were prepared using an instantaneous base-feeding method, employing sodium carbonate as the basification agent. The coagulation efficiency was significantly influenced by different B values. The results suggest that the humic acid removal increased with the increasing B value for PAC, while the inverse trend was observed for PTC. The optimum B value was chosen at 1.0 and 2.0 for PTC and PAC, respectively. Under the optimum coagulant dose and initial solution pH conditions, the PTC coagulant performed better than the PAC coagulant and the floc properties were significantly improved in terms of floc growth rate and floc size. However, the PAC coagulants produced flocs with better floc recoverability than the PTC coagulants. PMID:25291677
I A Bucklow; L E Drain
A method is described for the production of fine metal powders without contamination by striking sparks in liquid argon under pressure between two electrodes of the metal to be powdered. The particle size obtained is in the range 100 Å to 500 Å. In a test with a silver-cadmium alloy, considerable compositional inhomogeneities were produced; this effect may limit the
Resection of meningiomas with implantable microwave coagulation
Zhou, X.P.; Xie, Q.L.; Liu, J.M.; Yue, Z.J.; Cai, K.H. [Second Military Medical Univ., Shanghai (China)] [Second Military Medical Univ., Shanghai (China)
Implantable microwave coagulation was used to perform resection on 62 patients that had intracranial meningiomas. When 20--60 W microwave power was applied for 15 s, the temperature at the center of the tumor tissue was 43--63 C; 30 mm from the center, the temperature was under 40 C. Histological changes in the center of the tumor showed coagulative necrosis, diminished nuclei, and obliterated blood vessels. The changes at 10--20 mm from the center of the tumor showed coagulative necrosis and degeneration and, 30--50 mm from the center of the tumor, showed normal cell morphology after microwave coagulation. The thermal field in brain tumor has an effective diameter of about 40 mm. No side effects on the normal brain tissues were observed. The amount of blood loss during the operation was minimal while the meningioma was coagulated, especially when the meningioma was located at the skull base or in the parasagittal or cerebral convexity region. After microwave coagulation, the entire tumor could easily be removed. Among the 62 surgically treated cases, gross total tumor excision was 85%. No postoperative complications occurred after microwave coagulation, and there was no operative mortality in the series. The authors believe that this new technique has the advantage of simplicity, less blood loss, and smooth postoperative procedures. Hemostatic effects during the operation are satisfactory, and blood transfusion can be reduced by 50--60%.
Zimmerman, Theodore S.; Edgington, Thomas S.
Factor VIII coagulant activity (VIIIC) and the von Willebrand's disease antigen (Factor VIII-like antigen, vW-Ag) are biologically linked, and it has been suggested that they reside on the same molecule. However, insolubilized human isoantibody to VIIIC and rabbit antiserum containing antibodies to VIIIC and vW-Ag differentially bind and remove these entities from plasma, thus physically segregating one from the other. These findings indicate that Factor VIII coagulant activity resides on a molecule distinct from that expressing the von Willebrand's antigen. PMID:4542733
Coagulation processes with Gibbsian time evolution
Granovsky, Boris
We prove that time dynamics of a stochastic process of pure coagulation is given by a time dependent Gibbs distribution if and only if rates of single coagulations have the form $\\psi(i,j)=if(j)+jf(i)$, where $f$ is an arbitrary nonnegative function on the set of integers $\\ge 1$. We also obtained a recurrence relation for weights of these Gibbs distributions, that allowed explicit solutions in three particular cases of the function $f$. For the three corresponding models, we study the probability of coagulation into one giant cluster, at time $t>0.$
The singular coagulation equation with multiple fragmentation
NASA Astrophysics Data System (ADS)
Saha, Jitraj; Kumar, Jitendra
In this paper, we prove the global existence and uniqueness of the solutions to the initial-value problem for the coagulation-fragmentation equation with singular coagulation kernel and multiple fragmentation kernel. The solution obtained in this case also satisfies the mass conservation law. The proof is based on strong convergence methods applied to suitably chosen unbounded coagulation kernels having singularities in both the coordinate axes and satisfying certain growth conditions, which can possibly reach up to a quadratic growth at infinity, and the fragmentation kernel covers a very large class of unbounded functions.
Coagulation and fragmentation with discrete mass loss
NASA Astrophysics Data System (ADS)
Blair, Pamela N.; Lamb, Wilson; Stewart, Iain W.
A nonlinear integro-differential equation that models a coagulation and multiple fragmentation process in which discrete fragmentation mass loss can occur is examined using the theory of strongly continuous semigroups of operators. Under the assumptions that the coagulation kernel is bounded and the fragmentation rate function a satisfies a linear growth condition, global existence and uniqueness of solutions that lose mass in accordance with the model are established. In the case when no coagulation is present and the fragmentation process is governed by power-law kernels, an explicit formula is given for the substochastic semigroup associated with the resulting mass-loss fragmentation equation.
A preliminary study on cactus as coagulant in water treatment
Jingdong Zhang; Fang Zhang; Yuhong Luo; Hong Yang
The coagulation performance of cactus to act as natural macromolecular coagulant was studied by the jar test. The cactus coagulation attained comparatively high turbidity removal efficiency, and water with turbidity less than 5NTU could be obtained with initial turbidities from 20 to 200. When used to treat the same water sample, the optimum dosage of cactus coagulant was found similar
Mischler, Stéphane
FROM THE DISCRETE TO THE CONTINUOUS COAGULATION-FRAGMENTATION EQUATIONS Philippe Lauren¸cot1 and St´ephane Mischler2 Abstract The connection between the discrete and the continuous coagulation-frag- mentation coagulation-fragmentation model. 1 Introduction Coagulation and fragmentation processes arise in the dynamics
Self-similar solutions to a coagulation Veronique Bagland1
Bagland, Véronique
Self-similar solutions to a coagulation equation V´eronique Bagland1 and Philippe Lauren¸cot2 Math with a finite first moment is established for the Oort-Hulst-Safronov coagulation equation when the coagulation words: coagulation equation, Oort-Hust-Safronov model, self-similar solution, compact support. 1
Existence of self-similar solutions to Smoluchowski's coagulation equation
Henri Poincaré -Nancy-Université, Université
Existence of self-similar solutions to Smoluchowski's coagulation equation Nicolas Fournier #3's coagulation equation is conjec- tured since several years by physicists and numerical simulations have con#12 coagulation kernels. Key words. Smoluchowski's coagulation equation, self-similar solutions, mass conservation
Dynamics and scaling in models of coarsening and coagulation
Pego, Robert
Dynamics and scaling in models of coarsening and coagulation Robert L. Pego1 Abstract Clustering of coagulation and aggregation take the form of rate equations for cluster size distri- butions, mathematically and coagulation and their interrelations: Smoluchowski's coagulation equations, ballistic aggregation, Burgers
Ceragioli, Francesca
KINETIC MODELS FOR DUST COAGULATION IN INTERSTELLAR CLOUDS Luigi Barletti Dipartimento di In this paper we propose some kinetic models which take into account different mechanisms of coagulation between general mechanism of coagulation. 1 Introduction Dust coagulation is an important phenomenon
Original article Rennet coagulation of skim milk and curd drainage
Paris-Sud XI, Université de
Original article Rennet coagulation of skim milk and curd drainage: Effect of pH, casein coagulation, gel syneresis and drainage were tested. Coagulation was measured using a formagraphH and casein concentration on rennet coagulation, gel syneresis and drainage were in accordance with those
Effects of storage-induced platelet microparticles on the initiation and propagation phase of blood coagulation.
Keuren, Jeffrey F W; Keuren, Jeffery F W; Magdeleyns, Elke J P; Govers-Riemslag, José W P; Lindhout, Theo; Curvers, Joyce
Platelets shed microparticles, which support haemostasis via adherence to the damaged vasculature and by promoting blood coagulation. We investigated mechanisms through which storage-induced microparticles might support blood coagulation. Flow cytometry was used to determine microparticle number, cellular origin and surface expression of tissue factor (TF), procoagulant phosphatidylserine (PtdSer) and glycoprotein (GP) Ib-alpha. The influence of microparticles on initiation and propagation of coagulation were examined in activated factor X (factor Xa; FXa) and thrombin generation assays and compared with that of synthetic phospholipids. About 75% of microparticles were platelet derived and their number significantly increased during storage of platelet concentrates. About 10% of the microparticles expressed functionally active TF, as measured in a FXa generation assay. However, TF-driven thrombin generation was only found in plasma in which tissue factor pathway inhibitor (TFPI) was neutralised, suggesting that microparticle-associated TF in platelet concentrates is of minor importance. Furthermore, 60% of all microparticles expressed PtdSer. In comparison with synthetic procoagulant phospholipids, the maximal rate of thrombin formation in TF-activated plasma was 15-fold higher when platelet-free plasma was titrated with microparticles. This difference could be attributed to the ability of microparticles to propagate thrombin generation by thrombin-activated FXI. Collectively, our findings indicate a role of microparticles in supporting haemostasis by enhancement of the propagation phase of blood coagulation. PMID:16848773
Inhibiting the intrinsic pathway of coagulation with a FXII-targeting RNA Aptamer
Woodruff, R. S.; Xu, Y.; Layzer, J.; Wu, W.; Ogletreee, M.L.; Sullenger, B.A.
Background Exposure of the plasma protein factor XII to an anionic surface generates activated factor XII that not only triggers the intrinsic pathway of blood coagulation through the activatio of factor XI, but also mediates various vascular responses through activation of the plasma contact system. While deficiencies of factor XII are not associated with excessive bleeding, thrombosis models in factor deficient animals have suggested that this protein contributes to stable thrombus formation. Therefore, factor XII has emerged as an attractive therapeutic target to treat or prevent pathological thrombosis formation without increasing the risk for hemorrhage. Objectives Utilizing an in vitro directed evolution and chemical biology approach, we sought to isolate a nuclease resistant RNA aptamer that binds specifically to factor XII and directly inhibits factor XII coagulant function. Methods and Results Herein, we describe the isolation and characterization of a high affinity RNA aptamer targeting factor XII/XIIa that dose dependently prolongs fibrin clot formation and thrombin generation in clinical coagulation assays. This aptamer functions as a potent anticoagulant by inhibiting the autoactivation of factor XII, as well as inhibiting intrinsic pathway activation (factor XI activation). However, the aptamer does not affect the factor XIIa-mediated activation of the proinflammatory kallikrein-kinin system (plasma kallikrein activation). Conclusions We have generated a specific and potent factor XII/XIIa aptamer anticoagulant that offers targeted inhibition of discrete macromolecular interactions involved in the activation of the intrinsic pathway of blood coagulation. PMID:23692437
NASA Technical Reports Server (NTRS)
Northrop, T. G.
Dust grains immersed in plasma become charged. The charge is determined by the plasma characteristics, by secondary and photoemission from the grain, by grain velocity, and at any given instant by the past time history of the charging currents. This charge affects the Coulomb drag on a grain moving through the plasma. It affects the motion of the grain in an electromagnetic field of a planetary magnetosphere, and it is involved in the formation of the spokes in Saturn's rings and in the erosion of the rings by micrometeorites. And finally, it affects the coagulation rate of dust into larger bodies.
Ferric coagulant recovered from coagulation sludge and its recycle in chemically enhanced primary treatment.
Xu, G R; Yan, Z C; Wang, N; Li, G B
An investigation was conducted to study the feasibility of ferric coagulant recovery from chemical sludge and its recycle in chemically enhanced primary treatment (CEPT) to make the process more cost-effective, as well as reduce sludge volume. The optimum conditions and efficiency of the acidification for ferric coagulant recovery from coagulation sludge were investigated. Experimental results showed that the recovered coagulants can be used in CEPT and the pollutants removal efficiency is similar to that of fresh coagulant, and for some aspects the effect of recovered coagulants is better than that of fresh ones, such as turbidity removal. Although some substances will be enriched during recycle, they have little effect on treated wastewater quality. Acidification condition also had significant influence on reduction of sludge volume. The efficiency of coagulant recovery had a linear relationship with sludge reduction. Experiments verify that it would be a sustainable and cost-effective way to recover ferric coagulant from coagulation sludge in water treatment and chemical wastewater treatment, and then recycle it to CEPT, as well as reduce sludge volume. PMID:19587418
Particles in Surface Waters: Coagulation and Transport
Culkin, Gerald W.; Lawler, Desmond F.
that are nonlinear and highly size-dependent. Size-dependent transport and transformation mechanisms were simulated in this research to identify conditions in which coagulation is important. Explicit finite difference schemes for two-dimensional, laterally...
The role of argon metastables in operation and uniformity of planar RF inductively coupled discharges
Pierre, A.A.; Stewart, R.A.; Stittsworth, J.A.; Wendt, A.E. [Univ. of Wisconsin, Madison, WI (United States). Engineering Research Center for Plasma-Aided Manufacturing
The importance of metastables in the maintenance and uniformity of low pressure planar inductively coupled plasma (ICP) argon discharges have been a matter of some uncertainty. Previous modeling efforts have given varying results, with predictions of the contribution of two-step ionization via metastables ranging from negligible to 80% of the overall ionization rate. The abundance of argon metastables is important not only in making an accurate prediction of the ionization rate magnitude, but also in predicting its uniformity, and therefore the uniformity of the resulting plasma. Because the chemistry of argon is relatively simple, the argon ICP system presents an opportunity for straightforward verification of model performance. Measurements of argon metastable line densities along a radial chord in a cylindrical (20 cm D by 14 cm long) ICP discharge are made with a newly constructed broad-band xenon arc lamp optical absorption spectroscopic diagnostic. Concentrations of the 1S{sub 3} and 1S{sub 5} argon metastable states is determined, by measuring absorption lines at 795 and 811 nm, respectively. Predicted trends in the percent of ionization from metastables and excited levels with pressure and power are also presented. The influence of metastables on the electron density is examined by comparing fluid code results for electron density with and without the contribution of two-step ionization from metastables.
Coagulation of Oil in Water Using Sawdust and Bentonite and the Formation of a Floating Coagulated Material
Chung, Deborah D.L.
Coagulation of Oil in Water Using Sawdust and Bentonite and the Formation of a Floating Coagulated Material Tianlei Sun1 and D. D. L. Chung2 Abstract: The coagulation of oil in water is potentially cost-effective for removing oil from water. A coagulant consisting of sawdust (79.6% by volume), bentonite (15.8% by volume
Nuclear Quenching in Gaseous Argon
NASA Astrophysics Data System (ADS)
Kazkaz, Kareem; Bernstein, Adam; Foxe, Michael; Hagmann, Christian; Jovanovic, Igor; Stoeffl, Wolfgang; Winant, Celeste
In many media and with varying degrees of efficiency, nuclear recoils can induce ionization and/or scintillation. These nuclear recoil signatures can be used in dark matter searches and neutrino physics experiments, and to detect neutrons. To understand the behavior of the ionization process induced by nuclear recoils, nuclear quenching factors must be measured at various energies to properly reconstruct the recoil event. In this context, the quench factor is defined as the ratio of the number of electron-ion pairs produced by a nuclear recoil of a given energy to the number produced by an electron recoil of the same energy. Taking advantage of a unique 60 keV portable neutron source developed by LLNL, we will present latest results from our efforts to measure the nuclear quenching factor in gaseous argon at the lowest energy yet attempted. We also discuss using nuclear recoils in liquid argon to search for coherent neutrino scatters.
Dust Coagulation in Protoplanetary Accretion Disks
NASA Technical Reports Server (NTRS)
Schmitt, W.; Henning, Th.; Mucha, R.
The time evolution of dust particles in circumstellar disk-like structures around protostars and young stellar objects is discussed. In particular, we consider the coagulation of grains due to collisional aggregation. The coagulation of the particles is calculated by solving numerically the non-linear Smoluchowski equation. The different physical processes leading to relative velocities between the grains are investigated. The relative velocities may be induced by Brownian motion, turbulence and drift motion. Starting from different regimes which can be identified during the grain growth we also discuss the evolution of dust opacities. These opacities are important for both the derivation of the circumstellar dust mass from submillimeter/millimeter continuum observations and the dynamical behavior of the disks. We present results of our numerical studies of the coagulation of dust grains in a turbulent protoplanetary accretion disk described by a time-dependent one-dimensional (radial) alpha-model. For several periods and disk radii, mass distributions of coagulated grains have been calculated. From these mass spectra, we determined the corresponding Rosseland mean dust opacities. The influence of grain opacity changes due to dust coagulation on the dynamical evolution of a protostellar disk is considered. Significant changes in the thermal structure of the protoplanetary nebula are observed. A 'gap' in the accretion disk forms at the very frontier of the coagulation, i.e., behind the sublimation boundary in the region between 1 and 5 AU.
[Incidental finding of pathological coagulation parameters].
Luxembourg, B; Lindhoff-Last, E
Pathological coagulation parameters may reflect life-threatening hemorrhagic or thromboembolic diseases but may also be a laboratory result without any clinical significance, result from in vitro phenomena or preanalytical errors. This article gives an overview of potential pitfalls in coagulation diagnostics, lists the differential diagnoses of pathological coagulation parameters and describes further steps in the diagnostic approach to clarify pathological results. The focus lies on coagulation parameters that are frequently determined in routine clinical investigations, e.g. platelet count, prothrombin time, activated partial thromboplastin time (aPTT) and fibrinogen. Besides heparin, fondaparinux, danaparoid, and vitamin K antagonists, direct factor Xa inhibitors and direct thrombin inhibitors are nowadays available for therapeutic anticoagulation. This article gives an overview of the influence of anticoagulants on coagulation parameters which depends on the dose, the time of the last administration, as well as the method used for the determination of coagulation parameters. Moreover, common reasons for elevation of the fibrin degradation product D-dimer are presented. The clinical utility of D-dimer assays is limited by their poor specificity. Elevated D-dimer concentrations can be found in various diseases and also under normal physiological circumstances (e.g. in the elderly). Thus, the most useful clinical application of D-dimer is evidence of normal values to essentially rule out venous thromboembolism. PMID:25190093
Microwave diagnostics of atmospheric plasmas
NASA Astrophysics Data System (ADS)
Scott, David
Plasma treatment of biological tissues has tremendous potential due to the wide range of applications. Most plasmas have gas temperatures which greatly exceed room temperature. These are often utilized in electro-surgery for cutting and coagulating tissue. Another type of plasma, referred to as cold atmospheric plasma, or CAP, is characterized by heavy particle temperatures which are at or near room temperature. Due to this lack of thermal effect, CAP may provide less invasive medical procedures. Additionally, CAP have been demonstrated to be effective at targeting cancer cells while minimizing damage to the surrounding tissue. A recently fabricated Microwave Electron Density Device (MEDD) utilizes microwave scattering on small atmospheric plasmas to determine the electron plasma density. The MEDD can be utilized on plasmas which range from a fraction of a millimeter to several centimeters at atmospheric pressure when traditional methods cannot be applied. Microwave interferometry fails due to the small size of the plasma relative to the microwave wavelength which leads to diffraction and negligible phase change; electrostatic probes introduce very strong perturbation and are associated with difficulties of application in strongly-collisional atmospheric conditions; and laser Thomson scattering is not sensitive enough to measure plasma densities less than 1012 cm-3. The first part of this dissertation provides an overview of two types of small atmospheric plasma objects namely CAPs and plasmas utilized in the electro-surgery. It then goes on to describe the fabrication, testing and calibration of the MEDD facility. The second part of this dissertation is focused on the application of the MEDD and other diagnostic techniques to both plasma objects. A series of plasma images that illustrate the temporal evolution of a discharge created by an argon electrosurgical device operating in the coagulation mode and its behavior was analyzed. The discharge of the argon electrosurgical system was studied using an Intensified Charge-Coupled Device (ICCD) and the MEDD. The plasma density was measured and found to be in the range of (7.5-9.5) x 1015 cm-3 for applied powers of 15-60 Watts. The discharge can be classified as a glow discharge of alternating current with a contracted positive column. The discharge ignites every half-wave of the driving voltage when voltage increases above the breakdown threshold of about 300 Volts and is interrupted at the end of each half-wave when the voltage approaches zero. Additionally, it was shown that the plasma discharges on the target object during the positive half-wave of the voltage. The power distribution was also analyzed. It was found that 60-70% of the input power is delivered into the tissue and the remaining 30-40% is consumed by the plasma column between the electrosurgical probe and tissue. The application of the MEDD to a helium CAP revealed the temporal dynamics of the discharge. It was observed that streamer development associated with the measured plasma density peak is developing on the decaying part of the main inter-electrode discharge. The third part of the dissertation focuses on the simulation of a helium CAP. A one-dimensional model of a helium CAP was used to simulate twenty-one oxygen, helium, and nitrogen species. One hundred and forty reactions were successfully used. The predicted maximum and average densities of the species were tabulated. Graphs of the species densities were presented showing the change in densities with respect to the radius of the CAP. The plasma bullets can be seen via these graphs, with most species displaying maximum densities at a radius which is not the center of the CAP. This shows that the plasma bullets are a disk-like structure at the moment of time presented. Values of E/p were varied from 20 -- 30 volts/cm Torr. Based on experimental results of moments in time with which the maximum plasma density occurs, this data can be used to predict the actual E/p values for future experiments.
Coagulation algorithms with size binning
NASA Technical Reports Server (NTRS)
Statton, David M.; Gans, Jason; Williams, Eric
The Smoluchowski equation describes the time evolution of an aerosol particle size distribution due to aggregation or coagulation. Any algorithm for computerized solution of this equation requires a scheme for describing the continuum of aerosol particle sizes as a discrete set. One standard form of the Smoluchowski equation accomplishes this by restricting the particle sizes to integer multiples of a basic unit particle size (the monomer size). This can be inefficient when particle concentrations over a large range of particle sizes must be calculated. Two algorithms employing a geometric size binning convention are examined: the first assumes that the aerosol particle concentration as a function of size can be considered constant within each size bin; the second approximates the concentration as a linear function of particle size within each size bin. The output of each algorithm is compared to an analytical solution in a special case of the Smoluchowski equation for which an exact solution is known . The range of parameters more appropriate for each algorithm is examined.
Driven Brownian coagulation of polymers
NASA Astrophysics Data System (ADS)
Krapivsky, P. L.; Connaughton, Colm
We present an analysis of the mean-field kinetics of Brownian coagulation of droplets and polymers driven by input of monomers which aims to characterize the long time behavior of the cluster size distribution as a function of the inverse fractal dimension, a, of the aggregates. We find that two types of long time behavior are possible. For 0? a < 1/2 the size distribution reaches a stationary state with a power law distribution of cluster sizes having exponent 3/2. The amplitude of this stationary state is determined exactly as a function of a. For 1/2 < a ? 1, the cluster size distribution never reaches a stationary state. Instead a bimodal distribution is formed in which a narrow population of small clusters near the monomer scale is separated by a gap (where the cluster size distribution is effectively zero) from a population of large clusters which continue to grow for all time by absorbing small clusters. The marginal case, a=1/2, is difficult to analyze definitively, but we argue that the cluster size distribution becomes stationary and there is a logarithmic correction to the algebraic tail.
C5 chemotactic fragment induces leukocyte production of tissue factor activity: a link between complement and coagulation.
Muhlfelder, T W; Niemetz, J; Kreutzer, D; Beebe, D; Ward, P A; Rosenfeld, S I
Complement-activated human plasma causes generation of tissue factor in human leukocytes. This phenomenon appears to be related to the fifth component of complement (C5) as demonstrated by the use of C5 deficient-plasma and suppression of activity with antibody to C5. Isolation of the chemotactic factor from activated serum or trypsinization of purified C5 reproduces the phenomenon. These data provide evidence for a direct link between complement products and activation of the coagulation system. Because chemotactic peptides from C5 can be generated by a variety of enzymes, our findings suggest a relationship between complement, coagulation, and inflammation. PMID:762243
Effect of membrane pore size, coagulation time, and coagulant dose on virus removal by a coagulation-ceramic microfiltration hybrid system
T. Matsushita; Y. Matsui; N. Shirasaki; Y. Kato
We studied virus removal from spiked river water by an in-line coagulation-ceramic microfiltration hybrid system to investigate the effects of (1) coagulant dose (0.54, 1.08, and 1.62 mg Al\\/L), (2) pore size of the MF membrane (0.1, 0.5, and 1.0 ?m), and (3) coagulation time (1.1, 2.4, and 60 s). We found that (1) coagulant dose strongly affected virus removal.
Nickel atom and ion densities in an inductively coupled plasma with an internal coil
Economou, Demetre J.
Nickel atom and ion densities in an inductively coupled plasma with an internal coil Lin Xua Plasma was measured in an inductively coupled argon plasma with an internal Ni coil, as a function of pressure frequency rf high-density inductively coupled plasma ICP is created in an inert gas e.g., argon , usually
Helical Organization of Blood Coagulation Factor VIII on Lipid Nanotubes
Miller, Jaimy; Dalm, Daniela; Koyfman, Alexey Y.; Grushin, Kirill; Stoilova-McPhie, Svetla
Cryo-electron microscopy (Cryo-EM)1 is a powerful approach to investigate the functional structure of proteins and complexes in a hydrated state and membrane environment2. Coagulation Factor VIII (FVIII)3 is a multi-domain blood plasma glycoprotein. Defect or deficiency of FVIII is the cause for Hemophilia type A - a severe bleeding disorder. Upon proteolytic activation, FVIII binds to the serine protease Factor IXa on the negatively charged platelet membrane, which is critical for normal blood clotting4. Despite the pivotal role FVIII plays in coagulation, structural information for its membrane-bound state is incomplete5. Recombinant FVIII concentrate is the most effective drug against Hemophilia type A and commercially available FVIII can be expressed as human or porcine, both forming functional complexes with human Factor IXa6,7. In this study we present a combination of Cryo-electron microscopy (Cryo-EM), lipid nanotechnology and structure analysis applied to resolve the membrane-bound structure of two highly homologous FVIII forms: human and porcine. The methodology developed in our laboratory to helically organize the two functional recombinant FVIII forms on negatively charged lipid nanotubes (LNT) is described. The representative results demonstrate that our approach is sufficiently sensitive to define the differences in the helical organization between the two highly homologous in sequence (86% sequence identity) proteins. Detailed protocols for the helical organization, Cryo-EM and electron tomography (ET) data acquisition are given. The two-dimensional (2D) and three-dimensional (3D) structure analysis applied to obtain the 3D reconstructions of human and porcine FVIII-LNT is discussed. The presented human and porcine FVIII-LNT structures show the potential of the proposed methodology to calculate the functional, membrane-bound organization of blood coagulation Factor VIII at high resolution. PMID:24961276
Helical organization of blood coagulation factor VIII on lipid nanotubes.
Miller, Jaimy; Dalm, Daniela; Koyfman, Alexey Y; Grushin, Kirill; Stoilova-McPhie, Svetla
Cryo-electron microscopy (Cryo-EM)(1) is a powerful approach to investigate the functional structure of proteins and complexes in a hydrated state and membrane environment(2). Coagulation Factor VIII (FVIII)(3) is a multi-domain blood plasma glycoprotein. Defect or deficiency of FVIII is the cause for Hemophilia type A - a severe bleeding disorder. Upon proteolytic activation, FVIII binds to the serine protease Factor IXa on the negatively charged platelet membrane, which is critical for normal blood clotting(4). Despite the pivotal role FVIII plays in coagulation, structural information for its membrane-bound state is incomplete(5). Recombinant FVIII concentrate is the most effective drug against Hemophilia type A and commercially available FVIII can be expressed as human or porcine, both forming functional complexes with human Factor IXa(6,7). In this study we present a combination of Cryo-electron microscopy (Cryo-EM), lipid nanotechnology and structure analysis applied to resolve the membrane-bound structure of two highly homologous FVIII forms: human and porcine. The methodology developed in our laboratory to helically organize the two functional recombinant FVIII forms on negatively charged lipid nanotubes (LNT) is described. The representative results demonstrate that our approach is sufficiently sensitive to define the differences in the helical organization between the two highly homologous in sequence (86% sequence identity) proteins. Detailed protocols for the helical organization, Cryo-EM and electron tomography (ET) data acquisition are given. The two-dimensional (2D) and three-dimensional (3D) structure analysis applied to obtain the 3D reconstructions of human and porcine FVIII-LNT is discussed. The presented human and porcine FVIII-LNT structures show the potential of the proposed methodology to calculate the functional, membrane-bound organization of blood coagulation Factor VIII at high resolution. PMID:24961276
Solutions of the coagulation equation with time-dependent coagulation rates. [For stellar formation mass functions
Lejeune, C.; Bastien, P.
In attempting to reproduce the initial stellar mass function, the authors solved analytically the coagulation equation with an explicit time dependence in the coagulation rate in order to simulate the gravitational collapse of the fragments upon themselves as they move within the progenitor cloud. Two separate cases have been studied, with and without a mass dependence in the coagulation rate. The solutions show that: (1) inclusion of self-gravitation can change the results to the point of preventing coalescence to work altogether, depending on the values of the two free parameters; (2) the precise form of the mass dependence of the coagulation rate is not of prime importance in most situations of astrophysical interest; (3) coagulation alone is not sufficient to yield a realistic mass spectrum, and fragmentation must also be taken into account. 30 references.
Blood coagulation screening using a paper-based microfluidic lateral flow device.
Li, H; Han, D; Pauletti, G M; Steckl, A J
A simple approach to the evaluation of blood coagulation using a microfluidic paper-based lateral flow assay (LFA) device for point-of-care (POC) and self-monitoring screening is reported. The device utilizes whole blood, without the need for prior separation of plasma from red blood cells (RBC). Experiments were performed using animal (rabbit) blood treated with trisodium citrate to prevent coagulation. CaCl2 solutions of varying concentrations are added to citrated blood, producing Ca(2+) ions to re-establish the coagulation cascade and mimic different blood coagulation abilities in vitro. Blood samples are dispensed into a paper-based LFA device consisting of sample pad, analytical membrane and wicking pad. The porous nature of the cellulose membrane separates the aqueous plasma component from the large blood cells. Since the viscosity of blood changes with its coagulation ability, the distance RBCs travel in the membrane in a given time can be related to the blood clotting time. The distance of the RBC front is found to decrease linearly with increasing CaCl2 concentration, with a travel rate decreasing from 3.25 mm min(-1) for no added CaCl2 to 2.2 mm min(-1) for 500 mM solution. Compared to conventional plasma clotting analyzers, the LFA device is much simpler and it provides a significantly larger linear range of measurement. Using the red colour of RBCs as a visible marker, this approach can be utilized to produce a simple and clear indicator of whether the blood condition is within the appropriate range for the patient's condition. PMID:25144164
Argon microplasma diagnostics by diode laser absorption
Naoto Miura; Jun Xue; Jeffrey Hopwood
Argon kinetic gas temperature and line integrated resonance state (1s4) density in argon microplasma at 1-760 Torr were estimated by diode laser absorption. A 900 MHz microstrip split ring resonator (MSRR) was used as the microplasma generator. An argon atomic transition at 810.4 nm (1s4-2p7) was chosen as the absorption line. The wavelength of a single-mode laser diode was tuned
Magnetic particle imaging of blood coagulation
Murase, Kenya, E-mail: email@example.com; Song, Ruixiao; Hiratsuka, Samu [Department of Medical Physics and Engineering, Division of Medical Technology and Science, Faculty of Health Science, Graduate School of Medicine, Osaka University, Osaka 565-0871 (Japan)
We investigated the feasibility of visualizing blood coagulation using a system for magnetic particle imaging (MPI). A magnetic field-free line is generated using two opposing neodymium magnets and transverse images are reconstructed from the third-harmonic signals received by a gradiometer coil, using the maximum likelihood-expectation maximization algorithm. Our MPI system was used to image the blood coagulation induced by adding CaCl{sub 2} to whole sheep blood mixed with magnetic nanoparticles (MNPs). The "MPI value" was defined as the pixel value of the transverse image reconstructed from the third-harmonic signals. MPI values were significantly smaller for coagulated blood samples than those without coagulation. We confirmed the rationale of these results by calculating the third-harmonic signals for the measured viscosities of samples, with an assumption that the magnetization and particle size distribution of MNPs obey the Langevin equation and log-normal distribution, respectively. We concluded that MPI can be useful for visualizing blood coagulation.
A model for coagulation with mating
Raoul Normand
We consider in this work a model for aggregation, where the coalescing particles initially have a certain number of potential links (called arms) which are used to perform coagulations. There are two types of arms, male and female, and two particles may coagulate only if one has an available male arm, and the other has an available female arm. After a coagulation, the used arms are no longer available. We are interested in the concentrations of the different types of particles, which are governed by a modification of Smoluchowski's coagulation equation -- that is, an infinite system of nonlinear differential equations. Using generating functions and solving a nonlinear PDE, we show that, up to some critical time, there is a unique solution to this equation. The Lagrange Inversion Formula allows in some cases to obtain explicit solutions, and to relate our model to two recent models for limited aggregation. We also show that, whenever the critical time is infinite, the concentrations converge to a state where all arms have disappeared, and the distribution of the masses is related to the law of the size of some two-type Galton-Watson tree. Finally, we consider a microscopic model for coagulation: we construct a sequence of Marcus-Lushnikov processes, and show that it converges, before the critical time, to the solution of our modified Smoluchowski's equation.
Mathematical description of a direct current glow discharge in argon.
Bogaerts, A; Gijbels, R
In order to achieve a better understanding of the glow discharge, different models have been developed for the different species present in the plasma. An overview of the models is given and some typical results are presented. These results include, among others, the densities and energy distributions of the plasma species, the electric field and potential distribution, the contribution of different ionization mechanisms to the ionization of argon and sputtered atoms, the relative contribution of different plasma species to the sputtering process, and the variation of the cathode dark space length and the electrical current as functions of voltage and pressure. The validity of the present models is supported by the good agreement of the calculated current-voltage curves with experiment. PMID:15045278
Liquid Argon Calorimetry for ATLAS
NASA Astrophysics Data System (ADS)
Robinson, Alan
This summer, the largest collaborative physics project since the Manhattan project will go online. One of four experiments for the Large Hadron Collider at CERN in Geneva, ATLAS, employs over 2000 people. Canadians have helped design, construct, and calibrate the liquid argon calorimeters for ATLAS to capture the products of the high energy collisions produced by the LHC. From an undergraduate's perspective, explore how these calorimeters are made to handle their harsh requirement. From nearly a billion proton-proton collisions a second, physicists hope to discover the Higgs boson and other new fundamental particles.
Plasma Processing of Metallic and Semiconductor Thin Films in the Fisk Plasma Source
NASA Technical Reports Server (NTRS)
Lampkin, Gregory; Thomas, Edward, Jr.; Watson, Michael; Wallace, Kent; Chen, Henry; Burger, Arnold
The use of plasmas to process materials has become widespread throughout the semiconductor industry. Plasmas are used to modify the morphology and chemistry of surfaces. We report on initial plasma processing experiments using the Fisk Plasma Source. Metallic and semiconductor thin films deposited on a silicon substrate have been exposed to argon plasmas. Results of microscopy and chemical analyses of processed materials are presented.
Coagulation and fragmentation dynamics of inertial particles
Jens C. Zahnow; Rafael D. Vilela; Ulrike Feudel; Tamás Tél
Inertial particles suspended in many natural and industrial flows undergo coagulation upon collisions and fragmentation if their size becomes too large or if they experience large shear. Here we study this coagulation-fragmentation process in time-periodic incompressible flows. We find that this process approaches an asymptotic, dynamical steady state where the average number of particles of each size is roughly constant. We compare the steady-state size distributions corresponding to two fragmentation mechanisms and for different flows and find that the steady state is mostly independent of the coagulation process. While collision rates determine the transient behavior, fragmentation determines the steady state. For example, for fragmentation due to shear, flows that have very different local particle concentrations can result in similar particle size distributions if the temporal or spatial variation of shear forces is similar.
The effects of argon pressurization on melt rate and arc distribution during vacuum arc remelting of Alloy 718
Williamson, R.L.; Zanner, F.J. [Sandia National Labs., Albuquerque, NM (United States); Harrison, R. [Cameron Iron Works, Inc., Houston, TX (United States); Thompson, R. [Teledyne Allvac, Monroe, NC (United States)
The effects of argon addition to the vacuum arc remelting (VAR) process were studied in both laboratory and industrial experiments while remelting Alloy 718. The results demonstrate that argon can be added to an industrial VAR furnace to relatively high partial pressures without decreasing the melt rate, drip-short frequency, or constricting the arc plasma to a local region of the electrode surface. Laboratory experiments illustrate that this result is dependent on electrode chemistry, possibly related to magnesium content.
The effects of argon pressurization on melt rate and arc distribution during vacuum arc remelting of Alloy 718
Williamson, R.L.; Zanner, F.J. (Sandia National Labs., Albuquerque, NM (United States)); Harrison, R. (Cameron Iron Works, Inc., Houston, TX (United States)); Thompson, R. (Teledyne Allvac, Monroe, NC (United States))
The effects of argon addition to the vacuum arc remelting (VAR) process were studied in both laboratory and industrial experiments while remelting Alloy 718. The results demonstrate that argon can be added to an industrial VAR furnace to relatively high partial pressures without decreasing the melt rate, drip-short frequency, or constricting the arc plasma to a local region of the electrode surface. Laboratory experiments illustrate that this result is dependent on electrode chemistry, possibly related to magnesium content.
Comparison between decolorization of denim fabrics with Oxygen and Argon glow discharge
M. Ghoranneviss; S. Shahidi; B. Moazzenchi; A. Anvari; A. Rashidi; H. Hosseini
In this study, we have used a low temperature plasma, produced by a DC magnetron sputtering device, for decolorizing of denim fabrics, and the effect of using different gases such as Argon and Oxygen as the discharge medium have been investigated. The results obtained under equal periods of time have been compared and the effect of washing on the treated
A quantitative theory of noble gas ion laser discharge: Argon ion laser
C. C. Chen
Using the three temperature plasma formulation derived in an earlier paper, the authors have obtained numerical results for argon ion laser discharge parameter as functions of jR (the product of current density j and tube radius R) for selected values of pR (the product of the total filling pressure p and tube radius) at a fixed value of Tw (the
Development of the selective coagulation process
Yoon, R.H.; Luttrell, G.H.
The aim of this project is to develop an economical method for producing low-sulfur and low-ash coals using the selective hydrophobic coagulation (SHC) process. This work has been divided into three tasks: (1) project planning and sample acquisition; (2) studies of the fundamental mechanism(s) of the selective coagulation process and the parameters that affect the process of separating coal from both the ash-forming minerals and pyritic sulfur; and (3) bench-scale process development test work to establish the best possible method(s) of separating the hydrophobic and coagula from the dispersed mineral matter.
Observation of ? mode electron heating in dusty argon radio frequency discharges
Killer, Carsten; Bandelow, Gunnar; Schneider, Ralf; Melzer, André [Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald (Germany)] [Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald (Germany); Matyash, Konstantin [Universitätsrechenzentrum, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald (Germany)] [Universitätsrechenzentrum, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald (Germany)
The time-resolved emission of argon atoms in a dusty plasma has been measured with phase-resolved optical emission spectroscopy using an intensified charge-coupled device camera. For that purpose, three-dimensional dust clouds have been confined in a capacitively coupled rf argon discharge with the help of thermophoretic levitation. While electrons are exclusively heated by the expanding sheath (? mode) in the dust-free case, electron heating takes place in the entire plasma bulk when the discharge volume is filled with dust particles. Such a behavior is known as ? mode, first observed in electronegative plasmas. Furthermore, particle-in-cell simulations have been carried out, which reproduce the trends of the experimental findings. These simulations support previous numerical models showing that the enhanced atomic emission in the plasma can be attributed to a bulk electric field, which is mainly caused by the reduced electrical conductivity due to electron depletion.
Role of Coagulation in Xenobiotic-Induced Liver Injury
Sullivan, Bradley P.
The liver is a common target for xenobiotic-induced toxicity. Of importance, synthesis of soluble coagulation factors by the liver plays an essential role in hemostasis. Blood coagulation cascade activation is evident in both human patients...
Jones, M.E.; Winske, D.; Keinigs, R.; Lemons, D.
This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of this project has been to develop a fundamental understanding of dusty plasmas at the Laboratory. While dusty plasmas are found in space in galactic clouds, planetary rings, and cometary tails, and as contaminants in plasma enhanced fabrication of microelectronics, many of their properties are only partially understood. Our work has involved both theoretical analysis and self-consistent plasma simulations to understand basic properties of dusty plasmas related to equilibrium, stability, and transport. Such an understanding can improve the control and elimination of plasma dust in industrial applications and may be important in the study of planetary rings and comet dust tails. We have applied our techniques to the study of charging, dynamics, and coagulation of contaminants in plasma processing reactors for industrial etching and deposition processes and to instabilities in planetary rings and other space plasma environments. The work performed in this project has application to plasma kinetics, transport, and other classical elementary processes in plasmas as well as to plasma waves, oscillations, and instabilities.
Algorithm-based coagulation management of catastrophic amniotic fluid embolism.
Annecke, Thorsten; Geisenberger, Thomas; Kürzl, Rainer; Penning, Randolph; Heindl, Bernhard
Amniotic fluid embolism (AFE) is a rare, but often catastrophic, complication of pregnancy and associated with severe coagulopathy. We present an algorithm-based approach in managing coagulopathy and hemorrhage in a fatal case of histopathologically proven AFE. Thrombelastometry was used for rapid evaluation of the coagulation status. Stop of extensive hyperfibrinolysis with tranexamic acid, stabilization of initial clot formation with high-dose fibrinogen and platelet transfusions, and use of prothrombin complex concentrate together with a 1: 1 transfusion regimen of red packed cells and fresh frozen plasma was successful to control diffuse bleeding and restore clot firmness after hysterectomy. Stable clotting situation was maintained despite further clinical deterioration and development of multiple organ failure in this patient. PMID:20040855
Evaluation of Blood Coagulation-Fibrinolysis System in Patients Receiving Chronic Hemodialysis
Yoshitaka Ishii; Shintaro Yano; Hideo Kanai; Akira Maezawa; Akiyasu Tsuchida; Ryouji Wakamatsu; Takuji Naruse
We determined plasma levels of thrombomodulin, thrombin-antithrombin III complex (TAT), protein C, protein S, and plasmin-?2 plasmin inhibitor complex (PIC) before and after hemodialysis in 54 patients receiving chronic hemodialysis, to evaluate the blood-coagulation system and to evaluate the antithrombogenicity of various dialyzer membranes. Predialysis levels of thrombomodulin and TAT were both significantly increased compared with normal control values, but
The In Vitro Effects of Antithrombin III on the Activated Coagulation Time in Patients on Heparin Therapy
Jerrold H. Levy; Felix Montes; Fania Szlam; Christopher D. Hillyer
Heparin requires antithrombin III (AT) to achieve anti- coagulation, and patients on continuous small-dose heparin preoperatively experience decreased levels of AT-causing heparin resistance. When this occurs, 2- 4 units of fresh frozen plasma (;1000 units of AT) are often administered to increase AT levels and restore heparin responsiveness. We evaluated purified human AT concentrate (Thrombate III; Bayer, Inc., Elkhart, IN)
Fast and interrupted expansion in cyclic void growth in dusty plasma
NASA Astrophysics Data System (ADS)
van de Wetering, F. M. J. H.; Brooimans, R. J. C.; Nijdam, S.; Beckers, J.; Kroesen, G. M. W.
Low-pressure acetylene plasmas are able to spontaneously form dust particles. This will result in a dense cloud of solid particles that is levitated in the plasma. The formed particles can grow up to micrometers. We observed a spontaneous interruption in the expansion of the so-called dust void. A dust void is a macroscopic region in the plasma that is free of nanoparticles. The phenomenon is periodical and reproducible. We refer to the expansion interruption as 'hiccup'. The expanding void is an environment in which a new cycle of dust particle formation can start. At a certain moment in time, this cycle reaches the (sudden) coagulation phase and as a result the void will temporarily shrink. To substantiate this reasoning, the electron density is determined non-intrusively using microwave cavity resonance spectroscopy. Moreover, video imaging of laser light scattering of the dust particles provides their spatial distribution. The emission intensity of a single argon transition is measured similarly. Our results support the aforementioned hypothesis for what happens during the void hiccup. The void dynamics preceding the hiccup are modeled using a simple analytical model for the two dominant forces (ion drag and electric) working on a nanoparticle in a plasma. The model results qualitatively reproduce the measurements.
Mathematical Model for the Blood Coagulation Prothrombin Time Test
Mikhail A Khanin; Dmitrii V Rakov; Alexander E Kogan
A mathematical model for the prothrombin time test is proposed. The time course of clotting factor activation during coagulation was calculated, and the sensitivity of the test to a decrease in the concentrations of coagulation proteins or their activities was studied. The model predicts that only severe coagulation disorders connected with a more than five-fold decrease in the concentrations or
On a quasilinear coagulation-fragmentation model with di usion
Amann, Herbert
On a quasilinear coagulation-fragmentation model with di#11;usion Herbert Amann and Frank Weber the mathematical theory of coagulation-fragmentation processes has made considerable progress. Many contributions of countable reaction-di#11;usion systems, describing coagulation-fragmentation processes, is due to Ph. B#19
Weak Solutions to the Continuous Coagulation Equation with Multiple Fragmentation
Paris-Sud XI, Université de
Weak Solutions to the Continuous Coagulation Equation with Multiple Fragmentation Ankik Kumar Giri, 2011 Abstract The existence of weak solutions to the continuous coagulation equation with mul- tiple fragmentation is shown for a class of unbounded coagulation and fragmentation kernels, the fragmentation kernel
Mischler, Stéphane
THE CONTINUOUS COAGULATION-FRAGMENTATION EQUATIONS WITH DIFFUSION Philippe Lauren¸cot1 and St´ephane Mischler2 Abstract Existence of global weak solutions to the continuous coagulation-fragmentation equations or the coagulation coefficient enjoys a monotonicity condition. Our approach relies on weak and strong compactness
EAS 6795 Atmospheric Aerosols Homework Assignment 6, Coagulation
Weber, Rodney
EAS 6795 Atmospheric Aerosols Homework Assignment 6, Coagulation Note: Problems 1, 2 and 3 concentration for an aerosol 5 hrs old? Assume a coagulation coefficient of 3x1016 m3 /s (3x10-10 cm3 /s). 2 that will have twice the initial particle mass after 10 min. Assume simple monodisperse coagulation. Neglect
Predicted Solution Structure of Zymogen Human Coagulation FVII
Perera, Lalith
Predicted Solution Structure of Zymogen Human Coagulation FVII LALITH PERERA,1 THOMAS A. DARDEN,2-ray crystallographic structure of human coagulation FVIIa/TF complex bound with calcium ions (Banner et al., Nature dynamics simulations; FVII; tissue factor; EGF-like domains; serine protease Introduction Blood coagulation
Strongly Differentiable Solutions of the Discrete Coagulation-Fragmentation Equation
Mottram, Nigel
Strongly Differentiable Solutions of the Discrete Coagulation-Fragmentation Equation A. C. Mc differential equations that models the coagulation and fragmentation of clusters. In contrast to previous are established under minimal restrictions on the fragmentation rates, but with the coagulation rates assumed
Self-similarity in Smoluchowski's coagulation Barbara Niethammer
Jensen, Max
Self-similarity in Smoluchowski's coagulation equations Barbara Niethammer University of Oxford J.B. McLeod (Oxford) and J. Vel´azquez (Bonn) #12;Coagulation Motivation: (Smoluchowski, Z. phys. Chemie, 1917) Coagulation in homogeneous colloidal gold solution Setting Uniformly distributed particles x (0
ORIGINAL PAPER Acid coagulation behavior of homogenized milk: effect
Paris-Sud XI, Université de
ORIGINAL PAPER Acid coagulation behavior of homogenized milk: effect of interacting and non the early stages of the acid coagulation behavior of milk containing homogenized fat globules. By addition of Tween did not overly affect the acid coagulation behavior of the casein micelles. The initial stages
Uniqueness and regularity of scaling profiles for Smoluchowski's coagulation equation
Boyer, Edmond
Uniqueness and regularity of scaling profiles for Smoluchowski's coagulation equation St are asymptotic at y = 0, are equal. Our methods include a new representation of the coagulation operator . . . . . . . . . . . . . . . . 9 2 Preliminaries: self-similar profiles 9 3 A representation of the coagulation operator 10 1 hal
Local and Global Strong Solutions to Continuous Coagulation-Fragmentation
Amann, Herbert
Local and Global Strong Solutions to Continuous Coagulation-Fragmentation Equations with Diffusion, Nashville, TN 37240, USA Abstract We consider the diffusive continuous coagulation-fragmentation equations-in-time existence in the absence of frag- mentation. Key words: coagulation, fragmentation, volume scattering
The scaling attractor and ultimate dynamics for Smoluchowski's coagulation equations
The scaling attractor and ultimate dynamics for Smoluchowski's coagulation equations Govind Menon1's coagulation equation for the three simplest rate kernels K(x, y) = 2, x + y and xy. In another work, we (dust and gel). Keywords: dynamic scaling, agglomeration, coagulation, coalescence, infi- nite
A Remark on Continuous Coagulation-Fragmentation Equations with
Walker, Christoph
A Remark on Continuous Coagulation-Fragmentation Equations with Unbounded Diffusion Coefficients 37240, USA email@example.com Abstract. Continuous coagulation-fragmentation processes and the author on diffusive continuous coagulation-fragmentation equations [4] to the case of unbounded diffusion
Filbet, Francis
AN ASYMPTOTICALLY STABLE SCHEME FOR DIFFUSIVE COAGULATION-FRAGMENTATION MODELS FRANCIS FILBET Abstract. This paper is devoted to the analysis of a numerical scheme for the coagulation and fragmentation of the space nonhomogeneous coagulation-fragmentation model. It is shown that the scheme preserves positivity
Dynamics and scaling in models of coarsening and coagulation
Pego, Robert
Dynamics and scaling in models of coarsening and coagulation Robert L. Pego1 Abstract Clustering of coagulation and aggregation take the form of rate equations for cluster size distri- butions, mathematically behavior in complex systems. Some funda- mental models of clustering and coagulation
ORIGINAL PAPER Variations in coagulation properties of cheese milk
Boyer, Edmond
ORIGINAL PAPER Variations in coagulation properties of cheese milk from three Danish dairy breeds a study on the variation of coagulation properties in individual cow's milk measured by a novel free of poorly and even non-coagulating (NC) milk in Denmark, and based on that, the paper reports
A pure jump Markov process associated with Smoluchowski's coagulation equation
Henri Poincaré -Nancy-Université, Université
A pure jump Markov process associated with Smoluchowski's coagulation equation Madalina firstname.lastname@example.com Abstract The Smoluchowski coagulation equation models the evolution of the density n(x;t) of the particles is the solution of the Smoluchowski's coagulation equation. This ap- proach is at our knowledge the #12;rst
Paris-Sud XI, Université de
THE COAGULATION - FRAGMENTATION EQUATION AND ITS STOCHASTIC COUNTERPART EDUARDO CEPEDA ABSTRACT. We consider a coagulation multiple-fragmentation equation, which describes the concentration ct-adapted to coalescence phenomena. It was introduced in previous works on coagulation and coalescence. Mathematics Subject
Bipolar coagulation of vessels in aesthetic plastic surgery
Héctor Marino
Bipolar coagulation for hemostasis should be used more frequently than monopolar coagulation in aesthetic plastic surgery. The advantages of the procedure are manifold: considerable reduction of the amount of current, and consequent prevention of deleterious effects on other tissues and organs; minimal devitalization of tissues during coagulation; reduction of reactive edema; total separation of the patient from the power source
Hydrofluorocarbon ion density of argon- or krypton-diluted CH2F2 plasmas: generation of CH2F+ and CHF2+ by dissociative-ionization in charge exchange collisions
NASA Astrophysics Data System (ADS)
Kondo, Yusuke; Miyawaki, Yudai; Ishikawa, Kenji; Hayashi, Toshio; Takeda, Keigo; Kondo, Hiroki; Sekine, Makoto; Hori, Masaru
Ion densities of CH2F+ and CHF2+ were determined by dissociative ionization pathways in channels of charge exchange collisions, i.e. CH2F2 + M+ ? CH2F+ + F + M* and CHF2+ + H +M* [M = Ar, Kr] in CH2F2 plasmas diluted by a rare gas [M]. These channels simultaneously generated counter fragments of charge-neutral H and F atoms of interest for plasma etching processes. In Ar-diluted plasmas, CH2F+ ions predominated due to dissociative ionization between Ar+ [ca. 15.8?eV] and C–F appearance [dissociative ionization] energy [ca. 16?eV] to form CH2F+. In contrast, for Kr-diluted plasmas, C–H appearance energy [ca. 13.8?eV] predominated to produce a larger amount of CHF2+ ions due to a similar channel for charge exchange collisions between Kr+ [ca. 14?eV] and CH2F2. Thus, adding the ratio of Ar and Kr gas to CH2F2 plasmas provided control over the fraction of CH2F+ and CHF2+ ion densities.
Propagation of Chaos in a Coagulation Model
Escobedo, Miguel
A deterministic coalescing dynamics with constant rate for a particle system in a finite volume with a fixed initial number of particles is considered. It is shown that, in the thermodynamic limit, with the constraint of fixed density, the corresponding coagulation equation is recovered and global in time propagation of chaos holds.
Development of the Selective Hydrophobic Coagulation process
Yoon, R.H.; Luttrell, G.H.
A novel technique for selectively coagulating and separating coal from dispersed mineral matter has been developed at Virginia Tech. The process, Selective Hydrophobic Coagulation (SHC), has been studied since 1986 under the sponsorship of the US Department of Energy (Contracts AC22-86PC91221 and AC22-90PC90174). The SHC process differs from oil agglomeration, shear or polymer flocculation, and electrolytic coagulation processes in that it does not require reagents or additives to induce the formation of coagula. In most cases, simple pH control is all that is required to (1) induce the coagulation of coal particles and (2) effectively disperse particles of mineral matter. If the coal is oxidized, a small dosage of reagents can be used to enhance the process. During the quarter, the Anutech Mark IV surface force apparatus was used to generate surface force-distance data for the mica/dodecylamine hydrochloride system (Task 2.1.1). Work to characterize the hydrophobicity of this system and the mica/DDOA[sup [minus
Development of the selective hydrophobic coagulation process
Yoon, R.H.; Luttrell, G.H.
A novel technique for selectively coagulating and separating coal from dispersed mineral matter has been developed at Virginia Tech. The process, Selective Hydrophobic Coagulation (SHC), has been studied since 1986 under the sponsorship of the US Department of Energy. The SHC process differs from oil agglomeration, shear or polymer flocculation, and electrolytic coagulation processes in that it does not require reagents or additives to induce the formation of coagula. In most cases, simple pH control is all that is required to (i) induce the coagulation of coal particles and (ii) effectively disperse particles of mineral matter. If the coal is oxidized, a small dosage of reagents can be used to enhance the process. The technical work program was initiated on July 1, 1992. Force-distance curves were generated for DDOA Br-coated mica surfaces in water and used to calculate hydrophobicity constants and decay lengths for this system; and a new device for the measurement of water contact angles, similar to the Wilhelmy plate balance, has been built 225 kg samples of Pittsburgh No. 8 and Elkhom No. 3 seam coals were obtained; a static mixer test facility for the study of coagula growth was set up and was undergoing shakedown tests at the end of the quarter; a bench-scale lamella thickener was being constructed; and preliminary coagula/ mineral separation tests were being conducted in a bench-scale continuous drum filter.
Blood Coagulation Initiates Respiratory Burst in Neutrophils
I. G. Gerasimov; D. Yu. Ignatov
Using the in vitro reaction of nitroblue tetrazolium reduction we showed that blood coagulation stimulates production of reactive oxygen species by human neutrophils. Heparin and chondroitin sulfate produced by thrombin-activated basophils are good candidates for inductors of these processes. Similar activation probably occurs in vivo under the influence of inductors secreted by mast cells.
Roles for vitamin K beyond coagulation
Technology Transfer Automated Retrieval System (TEKTRAN)
Recent interest in vitamin K has been motivated by evidence of physiological roles beyond that of coagulation. Vitamin K and vitamin K-dependent proteins may be involved in regulation of calcification, energy metabolism, and inflammation. However, the evidence for many of these proposed roles in the...
Complications of radiofrequency coagulation of liver tumours
S. Mulier; P. Mulier; Y. Ni; Y. Miao; B. Dupas; G. Marchal; I. De Wever; L. Michel
Background: Radiofrequency coagulation (RFC) is being promoted as a novel technique with a low morbidity rate in the treatment of liver tumours. The purpose of this study was to assess critically the complication rates of RFC in centres with both large and limited initial experience, and to establish causes and possible means of prevention and treatment. Methods: This is an
Propagation of Chaos in a Coagulation Model
Miguel Escobedo; Federica Pezzotti
A deterministic coalescing dynamics with constant rate for a particle system in a finite volume with a fixed initial number of particles is considered. It is shown that, in the thermodynamic limit, with the constraint of fixed density, the corresponding coagulation equation is recovered and global in time propagation of chaos holds.
Chronic Rhinosinusitis and the Coagulation System.
Kim, Dong Young; Cho, Seong H; Takabayashi, Tetsuji; Schleimer, Robert P
Chronic rhinosinusitis (CRS) is one of the most common chronic diseases in adults and severely affects quality of life in patients. Although various etiologic and pathogenic mechanisms of CRS have been proposed, the causes of CRS remain uncertain. Abnormalities in the coagulation cascade may play an etiologic role in many diseases, such as asthma and other inflammatory conditions. While studies on the relationship between asthma and dysregulated coagulation have been reported, the role of the coagulation system in the pathogenesis of CRS has only been considered following recent reports. Excessive fibrin deposition is seen in nasal polyp (NP) tissue from patients with chronic rhinosinusitis with nasal polyp (CRSwNP) and is associated with activation of thrombin, reduction of tissue plasminogen activator (t-PA) and upregulation of coagulation factor XIII-A (FXIII-A), all events that can contribute to fibrin deposition and crosslinking. These findings were reproduced in a murine model of NP that was recently established. Elucidation of the mechanisms of fibrin deposition may enhance our understanding of tissue remodeling in the pathophysiology of NP and provide new targets for the treatment of CRSwNP. PMID:26122502
Decision model for coagulant dosage using genetic programming and multivariate statistical analysis for coagulation\\/flocculation at water treatment process
Hyeon Bae; Changwon Kim
In this research, genetic programming and multivariate statistical analysis techniques have been applied for decision support\\u000a on the coagulant dosage and the mixing ratio as two kinds of coagulants have been injected at the same time in the coagulating\\u000a sedimentation process of water treatment. The coagulant dosage has typically been determined through the Jar-test, which requires\\u000a a long experiment time
Effect of coagulation mechanism on membrane permeability in coagulation-assisted microfiltration for spent filter backwash water recycling
Chihpin Huang; Jr-Lin Lin; Wen-Shan Lee; Jill R. Pan; Bingqing Zhao
Coagulation is an effective pre-treatment process in membrane filtration for recycling spent filter backwash water (SFBW). To optimize the operation of the coagulation\\/filtration process for SFBW recycling, it is important to understand the critical role of coagulation mechanism on membrane filtration. In this study, SFBW samples were coagulated with polyaluminum chloride (PACl), followed by a dead-end microfiltration (MF), and the
Imaging of hydrogen halides photochemistry on argon and ice nanoparticles
NASA Astrophysics Data System (ADS)
Poterya, V.; Lengyel, J.; Pysanenko, A.; Svr?ková, P.; Fárník, M.
The photodissociation dynamics of HX (X = Cl, Br) molecules deposited on large ArN and (H2O)N, bar{N}? 102-103, clusters is investigated at 193 nm using velocity map imaging of H and Cl photofragments. In addition, time-of-flight mass spectrometry after electron ionization complemented by pickup cross section measurements provide information about the composition and structure of the clusters. The hydrogen halides coagulate efficiently to generate smaller (HX)n clusters on ArN upon multiple pickup conditions. This implies a high mobility of HX molecules on argon. On the other hand, the molecules remain isolated on (H2O)N. The photodissociation on ArN leads to strong H-fragment caging manifested by the fragment intensity peaking sharply at zero kinetic energy. Some of the Cl-fragments from HCl photodissociation on ArN are also caged, while some of the fragments escape the cluster directly without losing their kinetic energy. The images of H-fragments from HX on (H2O)N also exhibit a strong central intensity, however, with a different kinetic energy distribution which originates from different processes: the HX acidic dissociation followed by H3O neutral hydronium radical formation after the UV excitation, and the slow H-fragments stem from subsequent decay of the H3O. The corresponding Cl-cofragment from the photoexcitation of the HCl.(H2O)N is trapped in the ice nanoparticle.
The immediate and late effects of thyroid hormone (triiodothyronine) on murine coagulation gene transcription.
Salloum-Asfar, Salam; Boelen, Anita; Reitsma, Pieter H; van Vlijmen, Bart J M
Thyroid dysfunction is associated with changes in coagulation. The aim of our study was to gain more insight into the role of thyroid hormone in coagulation control. C57Black/6J mice received a low-iodine diet and drinking water supplemented with perchlorate to suppress endogenous triiodothyronine (T3) and thyroxine (T4) production. Under these conditions, the impact of exogenous T3 on plasma coagulation, and hepatic and vessel-wall-associated coagulation gene transcription was studied in a short- (4 hours) and long-term (14 days) setting. Comparing euthyroid conditions (normal mice), with hypothyroidism (conditions of a shortage of thyroid hormone) and those with replacement by incremental doses of T3, dosages of 0 and 0.5 ?g T3/mouse/day were selected to study the impact of T3 on coagulation gene transcription. Under these conditions, a single injection of T3 injection increased strongly hepatic transcript levels of the well-characterized T3-responsive genes deiodinase type 1 (Dio1) and Spot14 within 4 hours. This coincided with significantly reduced mRNA levels of Fgg, Serpinc1, Proc, Proz, and Serpin10, and the reduction of the latter three persisted upon daily treatment with T3 for 14 days. Prolonged T3 treatment induced a significant down-regulation in factor (F) 2, F9 and F10 transcript levels, while F11 and F12 levels increased. Activity levels in plasma largely paralleled these mRNA changes. Thbd transcript levels in the lung (vessel-wall-associated coagulation) were significantly up-regulated after a single T3 injection, and persisted upon prolonged T3 exposure. Two-week T3 administration also resulted in increased Vwf and Tfpi mRNA levels, whereas Tf levels decreased. These data showed that T3 has specific effects on coagulation, with Fgg, Serpinc1, Proc, Proz, Serpin10 and Thbd responding rapidly, making these likely direct thyroid hormone receptor targets. F2, F9, F10, F11, F12, Vwf, Tf and Tfpi are late responding genes and probably indirectly modulated by T3. PMID:26011296
The Immediate and Late Effects of Thyroid Hormone (Triiodothyronine) on Murine Coagulation Gene Transcription
Salloum-Asfar, Salam; Boelen, Anita; Reitsma, Pieter H.; van Vlijmen, Bart J. M.
Thyroid dysfunction is associated with changes in coagulation. The aim of our study was to gain more insight into the role of thyroid hormone in coagulation control. C57Black/6J mice received a low-iodine diet and drinking water supplemented with perchlorate to suppress endogenous triiodothyronine (T3) and thyroxine (T4) production. Under these conditions, the impact of exogenous T3 on plasma coagulation, and hepatic and vessel-wall-associated coagulation gene transcription was studied in a short- (4 hours) and long-term (14 days) setting. Comparing euthyroid conditions (normal mice), with hypothyroidism (conditions of a shortage of thyroid hormone) and those with replacement by incremental doses of T3, dosages of 0 and 0.5 ?g T3/mouse/day were selected to study the impact of T3 on coagulation gene transcription. Under these conditions, a single injection of T3 injection increased strongly hepatic transcript levels of the well-characterized T3-responsive genes deiodinase type 1 (Dio1) and Spot14 within 4 hours. This coincided with significantly reduced mRNA levels of Fgg, Serpinc1, Proc, Proz, and Serpin10, and the reduction of the latter three persisted upon daily treatment with T3 for 14 days. Prolonged T3 treatment induced a significant down-regulation in factor (F) 2, F9 and F10 transcript levels, while F11 and F12 levels increased. Activity levels in plasma largely paralleled these mRNA changes. Thbd transcript levels in the lung (vessel-wall-associated coagulation) were significantly up-regulated after a single T3 injection, and persisted upon prolonged T3 exposure. Two-week T3 administration also resulted in increased Vwf and Tfpi mRNA levels, whereas Tf levels decreased. These data showed that T3 has specific effects on coagulation, with Fgg, Serpinc1, Proc, Proz, Serpin10 and Thbd responding rapidly, making these likely direct thyroid hormone receptor targets. F2, F9, F10, F11, F12, Vwf, Tf and Tfpi are late responding genes and probably indirectly modulated by T3. PMID:26011296
Could light meal jeopardize laboratory coagulation tests?
Lima-Oliveira, Gabriel; Salvagno, Gian Luca; Lippi, Giuseppe; Danese, Elisa; Gelati, Matteo; Montagnana, Martina; Picheth, Geraldo; Guidi, Gian Cesare
Background: Presently the necessity of fasting time for coagulation tests is not standardized. Our hypothesis is that this can harm patient safety. This study is aimed at evaluating whether a light meal (i.e. breakfast) can jeopardize laboratory coagulation tests. Materials and methods: A blood sample was firstly collected from 17 fasting volunteers (12 h). Immediately after blood collection, the volunteers consumed a light meal. Then samples were collected at 1, 2 and 4 h after the meal. Coagulation tests included: activated partial thromboplastin time (APTT), prothrombin time (PT), fibrinogen (Fbg), antithrombin III (AT), protein C (PC) and protein S (PS). Differences between samples were assessed by Wilcoxon ranked-pairs test. The level of statistical significance was set at P < 0.05. Mean % differences were determined and differences between and baseline and 1, 2 and 4h samples were compared with reference change value (RCV). Results: A significantly higher % activity of AT was observed at 1 h and 4 h after meal vs. baseline specimen [113 (104–117) and 111 (107–120) vs. 109 (102–118), respectively; P = 0.029 and P = 0.016]. APTT at 2 h was found significantly lower than baseline samples [32.0 (29.9–34.8) vs. 34.1 (32.2–35.2), respectively; P = 0.041]. The results of both Fbg and PS tests were not influenced by a light meal. Furthermore, no coagulation tests had significant variation after comparison with RCV. Conclusion: A light meal does not influence the laboratory coagulation tests we assessed, but we suggest that the laboratory quality managers standardize the fasting time for all blood tests at 12 hours, to completely metabolize the lipids intake. PMID:25351352
Coagulation and metastasis: what does the experimental literature tell us?
Gil-Bernabé, Ana M; Lucotti, Serena; Muschel, Ruth J
Inhibition of coagulation greatly limits cancer metastasis in many experimental models. Cancer cells trigger coagulation, through expression of tissue factor or P-selectin ligands that have correlated with worse prognosis in human clinical studies. Cancer cells also affect coagulation through expression of thrombin and release of microparticles that augment coagulation. In the cancer-bearing host, coagulation facilitates tumour progression through release of platelet granule contents, inhibition of Natural Killer cells and recruitment of macrophages. We are revisiting this literature in the light of recent studies in which treatment of clinical cohorts with anticoagulant drugs led to diminished metastasis. PMID:23691951
Electron scattering from argon: Data evaluation and consistency
Gargioni, E.; Grosswendt, B. [Physikalisch-Technische Bundesanstalt, 38116 Braunschweig (Germany)
The demand for coherent scattering data for modeling electron transport in matter has increased in recent years. While much effort has been devoted to the improvement of models describing electron transport and scattering, the updating of fundamental data sets on the basis of recent experimental results has often been neglected. The use of a well-validated set of electron cross sections ensures accurate calculations of transport parameters and ionization yields, with typical applications in material analysis, detector response studies, plasma diagnostics, physics of the atmosphere, and radiotherapy. Data consistency can be verified on the basis of various theoretical requirements, and systematic errors can be minimized by cross-checking results obtained from independent experiments. For example, the oscillator strength distribution of an atom can be obtained both from photoabsorption experiments and from zero-angle electron-atom collisions at high energy, on the basis of the Bethe theory. A considerable number of all electron-scattering experiments are concerned with light noble gases, in particular with argon. This gas is a dominant constituent of noble-gas discharge plasmas and plays an important role in rare-gas halide lasers and proportional scintillator counters. This work reviews electron-scattering cross sections and optical data for the argon atom, discusses the progress made in the field of electron scattering and photoabsorption, and focuses on the most appropriate criteria for verifying data consistency.
NASA Astrophysics Data System (ADS)
Zhang, H. Y.; Jin, C. G.; Yang, Y.; Ye, C.; Zhuge, L. J.; Wu, X. M.
As-deposited HfO2 films were modified by CHF3, C4F8, and mixed C4F8/O2 plasmas in a dual-frequency capacitively coupled plasma chamber driven by radio frequency generators of 60 MHz as the high frequency (HF) source and 2 MHz as the low frequency source (60/2 MHz). The influences of various surface plasma treatments under CHF3, C4F8, and C4F8/O2 were investigated in order to understand the chemical and structural changes in thin-film systems, as well as their influence on the electrical properties. Fluorine atoms were incorporated into the HfO2 films by either CHF3 or C4F8 plasma treatment; meanwhile, the C/F films were formed on the surface of the HfO2 films. The formation of C/F layers decreased the k value of the gate stacks because of its low dielectric constant. However, the addition of O2 gas in the discharge gases suppressed the formation of C/F layers. After thermal annealing, tetragonal HfO2 phase was investigated in both samples treated with CHF3 and C4F8 plasmas. However, the samples treated with O-rich plasmas showed monoclinic phase, which indicated that the addition of O plasmas could influence the Hf/O ratio of the HfO2 films. The mechanism of the t-HfO2 formation was attributed to oxygen insufficiency generated by the incorporation of F atoms. The capacitors treated with C4F8/O2 plasmas displayed the highest k value, which ascribed that the C/F layers were suppressed and the tetragonal phase of HfO2 was formed. Good electrical properties, especially on the hysteresis voltage and frequency dispersion, were obtained because the bulk traps were passivated by the incorporation of F atoms. However, the H-related traps were generated during the CHF3 plasma treatments, which caused the performance degradation. All the treated samples showed lower leakage current density than the as-deposited HfO2 films at negative bias due to the reduced trap-assisted tunneling by the incorporation of F to block the electrons transferring from metal electrode to the trap level.
Frequency dependent plasma characteristics in a capacitively coupled 300 mm wafer plasma processing chamber
Gregory A. Hebner; Edward V. Barnat; Paul A. Miller; Alex M. Paterson; John P. Holland
Argon plasma characteristics in a dual-frequency, capacitively coupled, 300 mm-wafer plasma processing system were investigated for rf drive frequencies between 10 and 190 MHz. We report spatial and frequency dependent changes in plasma parameters such as line-integrated electron density, ion saturation current, optical emission and argon metastable density. For the conditions investigated, the line-integrated electron density was a nonlinear function
MF/UF performance with and without coagulation
Robert, C.; Taylor, J.S.; Reiss, C.R.
Although size-exclusion membrane processes produce superior water quality relative to conventional surface water treatment, fouling can significantly limit the use of these membrane processes. Coagulation can reduce organic, particulate and biological fouling, and was investigated as a pretreatment process to microfiltration (MF) and ultrafiltration (UF) membrane processes. Varying coagulants, coagulant pH and dose and variation of conventional coagulation pretreatment processes including coagulation-sedimentation-filtration (CSF), coagulation-sedimentation (CS) and in-line coagulation (ILC) for varying dose and pH were investigated. The Hillsborough River, a highly organic productive subtropical surface water in Tampa, Florida and the Maumee River, a moderately productive northern US surface water were used as water sources for this study.
Argon recovery from partial oxidation based ammonia plant purge gases
R. Krishnamurthy; M. J. Andrecovich; D. L. MacLean; K. J. Wright
This patent describes a method for recovering argon from a feed mixture comprising argon, carbon monoxide, methane, hydrogen, and nitrogen. It comprises passing the feed mixture through a pressure swing adsorption system to remove carbon monoxide, methane and part of the nitrogen thereby producing a fraction containing an increased amount of argon; and passing the argon fraction to a cryogenic
Second Discharge Characteristics of Aluminum Wire Electrical Explosion Under Various Argon Pressures
NASA Astrophysics Data System (ADS)
Yan, Wenyu; Zhang, Qiaogen; Zhao, Junping; Chen, Gangliang; Liu, Longchen
Electrical wire explosion is a promising method for the preparation of metal nanopowder, but the properties of metal nanopowder are affected by the second discharge process of electrical wire explosion. The second discharge characteristics of aluminum wire electrical explosion under variant argon pressures were studied in a RLC discharge circuit. The results show that the curve of the second discharge voltages versus the pressure presents a U-shape. To clarify the roles of aluminum vapor and argon in the process of the second discharge, a spectrograph and a high speed framing camera were used to study the radiation spectrum and spatial distribution of the electrical explosion plasma. It is observed that argon participates in the second discharge process under low pressure. A discharge channel develops along the surface of the aluminum vapor. Under higher pressure, a second discharge takes place in the aluminum vapor and the discharge channel is inside the aluminum vapor.
A novel ?-fluidic whole blood coagulation assay based on Rayleigh surface-acoustic waves as a point-of-care method to detect anticoagulants
Meyer dos Santos, Sascha; Zorn, Anita; Guttenberg, Zeno; Picard-Willems, Bettina; Kläffling, Christina; Nelson, Karen; Klinkhardt, Ute; Harder, Sebastian
A universal coagulation test that reliably detects prolonged coagulation time in patients, irrespective of the anticoagulant administered, has not been available to date. An easily miniaturised, novel ?-fluidic universal coagulation test employing surface acoustic waves (SAW) is presented here. SAW was employed to instantly mix and recalcify 6??l citrated whole blood and image correlation analysis was used to quantify clot formation kinetics. The detection of clinically relevant anticoagulant dosing with old anticoagulants (unfractionated heparin, argatroban) and new anticoagulants (dabigatran, rivaroxaban) has been tested and compared to standard plasma coagulation assays. The applicability of this novel method has been confirmed in a small patient population. Coagulation was dose-proportionally prolonged with heparin, argatroban, dabigatran, and rivaroxaban, comparable to standard tests. Aspirin and clopidogrel did not interfere with the SAW-induced clotting time (SAW-CT), whereas the strong GPIIb/IIIa-inhibitor abciximab did interfere. Preliminary clinical data prove the suitability of the SAW-CT in patients being treated with warfarin, rivaroxaban, or dabigatran. The system principally allows assessment of whole blood coagulation in humans in a point-of-care setting. This method could be used in stroke units, emergency vehicles, general and intensive care wards, as well as for laboratory and home testing of coagulation. PMID:24404078
The coagulation characteristics of humic acid by using acid-soluble chitosan, water-soluble chitosan, and chitosan coagulant mixtures.
Chen, Chih-Yu; Wu, Chung-Yu; Chung, Ying-Chien
Chitosan is a potential substitute for traditional aluminium salts in water treatment systems. This study compared the characteristics of humic acid (HA) removal by using acid-soluble chitosan, water-soluble chitosan, and coagulant mixtures of chitosan with aluminium sulphate (alum) or polyaluminium chloride (PACl). In addition, we evaluated their respective coagulation efficiencies at various coagulant concentrations, pH values, turbidities, and hardness levels. Furthermore, we determined the size and settling velocity of flocs formed by these coagulants to identify the major factors affecting HA coagulation. The coagulation efficiency of acid- and water-soluble chitosan for 15?mg/l of HA was 74.4% and 87.5%, respectively. The optimal coagulation range of water-soluble chitosan (9-20?mg/l) was broader than that of acid-soluble chitosan (4-8?mg/l). Notably, acid-soluble chitosan/PACl and water-soluble chitosan/alum coagulant mixtures exhibited a higher coagulation efficiency for HA than for PACl or alum alone. Furthermore, these coagulant mixtures yielded an acceptable floc settling velocity and savings in both installation and operational expenses. Based on these results, we confidently assert that coagulant mixtures with a 1:1 mass ratio of acid-soluble chitosan/PACl and water-soluble chitosan/alum provide a substantially more cost-effective alternative to using chitosan alone for removing HA from water. PMID:25362971
nanofibers in air and argon atmospheres
NASA Astrophysics Data System (ADS)
Albetran, H.; Haroosh, H.; Dong, Y.; Prida, V. M.; O'Connor, B. H.; Low, I. M.
The effects of atmospheric air and argon environments on thermal-induced phase transformations in electrospun TiO2 nanofibers have been investigated in situ using synchrotron radiation diffraction. Diffraction results showed that the as-synthesized TiO2 nanofibers were initially amorphous, but crystallized to form anatase and rutile after thermal annealing in air or argon at elevated temperatures. The crystallization temperature of anatase was delayed by 100 °C in argon relative to in air, and the transformation of anatase into rutile occurs faster in argon atmosphere than in air due to the formation of oxygen vacancies. Non-linear strains formed in both polymorphs and the substantial elevation of rutile thermal expansion pointed to strain anisotropy in the rutile phase and the concomitant fibre breakage.
A microwave plasma cleaning apparatus
NASA Technical Reports Server (NTRS)
Tsai, C. C.; Nelson, W. D.; Schechter, D. E.; Thompson, L. M.; Glover, A. L.
In a microwave electron cyclotron resonance plasma source, reactive plasmas of oxygen and its mixtures of argon have been used for evaluating plasma cleaning technologies. Small aluminum samples (0.95 x 1.9 cm) were coated with thin films (less than or equal to 20 micrometers in thickness) of Shell Vitrea oil and cleaned with reactive plasmas. The discharge parameters, such as gas pressure, magnetic field, substrate biasing, and microwave power, were varied to change cleaning conditions. A mass spectroscopy (or residual gas analyzer) was used to monitor the status of plasma cleaning. Mass loss of the samples after plasma cleaning was measured to estimate cleaning rates. Measured cleaning rates of low-pressure (0.5-m torr) argon/oxygen plasmas were as high as 2.7 micrometers/min. X-ray photoelectron spectroscopy was used to determine cleanliness of the sample surfaces. In this paper, significant results of the plasma cleaning are reported and discussed.
Argon spectral function and neutrino interactions
Ankowski, A M; Ankowski, Artur M.; Sobczyk, Jan T.
The argon spectral function is constructed and used to calculate neutrino-argon cross sections. The approximations of the construction method are critically analyzed on the example of oxygen for which more detailed computations are available. The effective description of nucleus based on the information contained in a spectral function is proposed. It is demonstrated that its predictions are close to predictions of the complete spectral function. The effective description can be easily applied in Monte Carlo generators of events.
Can dust coagulation trigger streaming instability?
Drazkowska, Joanna
Streaming instability can be a very efficient way of overcoming growth and drift barriers to planetesimal formation. However, it was shown that strong clumping, which leads to planetesimal formation, requires a considerable number of large grains. State-of-the-art streaming instability models do not take into account realistic size distributions resulting from the collisional evolution of dust. We investigate whether a sufficient quantity of large aggregates can be produced by sticking and what the interplay of dust coagulation and planetesimal formation is. We develop a semi-analytical prescription of planetesimal formation by streaming instability and implement it in our dust coagulation code based on the Monte Carlo algorithm with the representative particles approach. We find that planetesimal formation by streaming instability may preferentially work outside the snow line, where sticky icy aggregates are present. The efficiency of the process depends strongly on local dust abundance and radial pressure g...
Coagulation phenotypes in septic shock as evaluated by calibrated automated thrombography.
Perrin, Julien; Charron, Cyril; François, Jean-Hugues; Cramer-Bordé, Elisabeth; Lévy, Bruno; Borgel, Delphine; Vieillard-Baron, Antoine
Sepsis induces alterations of coagulation suggesting both hypercoagulable or hypocoagulable features. The result of their combination remains unknown, making it difficult to predict whether one prevails over the other. Thrombin generation tests (TGTs) stand as an interesting tool to establish an integrative phenotype of coagulation. It has been reported that septic patients display a hypocoagulable trait using TGT. However, protein C (PC) system response was not evaluated. We aimed at describing the thrombin generation profile in patients with septic shock under conditions that are sensitive to PC system to evaluate the net results of coagulation abnormalities and to determine whether hypercoagulable or hypocoagulable traits coexist within a given individual. Thrombin generation was studied in plasma from patients presenting with septic shock at diagnosis and 6 h after a conventional therapeutic management using calibrated automated thrombography with or without thrombomodulin (TM) addition. Patients exhibit clear alterations of TGT that present as both consumption-related hypocoagulability (evidenced without TM addition) but also hypercoagulability by decreased sensitivity to the PC system evidenced with TM addition. No difference could be demonstrated between survivors and nonsurvivors at Day 28, but patients who do not respond to therapeutics at 6 h seem to be more hypercoagulable. More importantly, if our results evidence heterogeneity between patients, we show that alterations of coagulation result in an equilibrium in the majority of patients, thus suggesting "normocoagulability"; but, in the presence of a biological imbalance between baseline thrombin generation and sensitivity to TM, the global effect mostly tends toward hypercoagulability. Thus, TGT may help identify distinct biological coagulation phenotypes in the complex alterations induced by sepsis. PMID:25255379
Fast-imaging and spectroscopic analysis of atmospheric argon streamers for large gap arc breakdown
NASA Astrophysics Data System (ADS)
Pachuilo, Michael; Stefani, Francis; Bengtson, Roger; Raja, Laxminarayan
A non-equilibrium plasma source has been developed to assist in the low-voltage arc breakdown of large electrode gaps. The source consists of a dielectric embedded wire helically wound around a confining cylindrical quartz chamber. Annular electrodes cap the ends of the quartz chamber. An argon feed gas is used to provide a uniform environment and exhausts to ambient atmospheric conditions. A negative polarity 50 kV trigger pulse is applied to the embedded trigger wire to initiate the arc breakdown. Application of the trigger pulse produces a localized coronal discharges along the inner surface of the quartz tube. The corona provides seed electrons through which streamers propagate from one of the main discharge electrode along the quartz surface until it reaches the opposite electrode to bridge the gap. Once the gap is bridged a spark over occurs and robust arc discharge is formed in the chamber volume. Fast imaging of the streamer propagation establishes its velocity in the range of ~ 100 km/s. Spectroscopy of the streamer discharge in atmospheric argon has been conducted and electron temperature and number density estimated from a collision radiative model. Argon spectrum is dominated by neutral argon lines in the 650--950 nm range, and singly ionized argon lines are observed in the ultra-violet to near UV (300--400 nm). Research was performed in connection with AFOSR Contract FA9550-11-1-0062.
Cardiovascular and blood coagulative effects of pulmonary zinc exposure
Gilmour, Peter S. [Center for Environmental Medicine, Asthma and Lung Biology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 (United States); Nyska, Abraham [Laboratory of Experimental Pathology, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709 (United States); Schladweiler, Mette C. [Pulmonary Toxicology Branch, MD B143-01, Experimental Toxicology Division, National Health and Environmental Effects Research Laboratory, ORD, US Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); McGee, John K. [Pulmonary Toxicology Branch, MD B143-01, Experimental Toxicology Division, National Health and Environmental Effects Research Laboratory, ORD, US Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); Wallenborn, J. Grace [Department of Environmental Sciences and Engineering, UNC School of Public Health, Chapel Hill, NC 27599 (United States); Richards, Judy H. [Pulmonary Toxicology Branch, MD B143-01, Experimental Toxicology Division, National Health and Environmental Effects Research Laboratory, ORD, US Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); Kodavanti, Urmila P. [Pulmonary Toxicology Branch, MD B143-01, Experimental Toxicology Division, National Health and Environmental Effects Research Laboratory, ORD, US Environmental Protection Agency, Research Triangle Park, NC 27711 (United States)]. E-mail: email@example.com
Cardiovascular damage induced by pulmonary exposure to environmental chemicals can result from direct action or, secondarily from pulmonary injury. We have developed a rat model of pulmonary exposure to zinc to demonstrate cardiac, coagulative, and fibrinolytic alterations. Male Wistar Kyoto rats were instilled intratracheally with saline or zinc sulfate, 131 {mu}g/kg (2 {mu}mol/kg); the alterations were determined at 1, 4, 24, and 48 h postexposure. High-dose zinc enabled us to show changes in circulating levels of zinc above normal and induce significant pulmonary inflammation/injury such that cardiac impairments were likely. At 1-24 h postexposure, plasma levels of zinc increased to nearly 20% above the base line. Significant pulmonary inflammation and injury were determined by analysis of bronchoalveolar lavage fluid and histopathology in zinc-exposed rats at all time points. Starting at 4 h postexposure, pulmonary damage was accompanied by persistently increased gene expressions of tissue factor (TF) and plasminogen activator-inhibitor-1 (PAI-1), but not thrombomodulin (TM). Cardiac tissues demonstrated similar temporal increases in expressions of TF, PAI-1, and TM mRNA following pulmonary instillation of zinc. In contrast to extensive pulmonary edema and inflammation, only mild, and focal acute, myocardial lesions developed in a few zinc-exposed rats; no histological evidence showed increased deposition of fibrin or disappearance of troponin. At 24 and 48 h postexposure to zinc, increases occurred in levels of systemic fibrinogen and the activated partial thromboplastin time. These data suggest that cardiovascular blood coagulation impairments are likely following pulmonary zinc exposure and associated pulmonary injury and inflammation.
Comparison of Stress-Hemoconcentration Correction Techniques for Stress-Induced Coagulation
Austin, Anthony W.; Patterson, Stephen M.
When examining stress effects on coagulation, arithmetic correction is typically used to adjust for concomitant hemoconcentration but may be inappropriate for coagulation activity assays. We examined a new physiologically relevant method of correcting for stress-hemoconcentration. Blood was drawn from healthy men (N = 40) during baseline, mental stress, and recovery, and factor VII activity (FVII:C), factor VIII activity (FVIII:C), activated partial thromboplastin time (APTT), prothrombin time (PT%), fibrinogen, D-dimer, and plasma volume were determined. Three hemoconcentration correction techniques were assessed: arithmetic correction and two reconstitution techniques using baseline plasma or physiological saline. Area-under-the-curve (AUC) was computed for each technique. For FVII:C, uncorrected AUC was significantly greater than AUC corrected arithmetically. For PT%, uncorrected AUC was significantly greater than AUC corrected with saline or arithmetically. For APTT, uncorrected AUC was significantly less than AUC corrected with saline and greater than AUC corrected arithmetically. For fibrinogen, uncorrected AUC was significantly greater than AUC corrected with saline or arithmetically. For D-dimer, uncorrected AUC was significantly greater than AUC corrected arithmetically. No differences in AUC were observed for FVIII:C. Saline reconstitution seems most appropriate when adjusting for hemoconcentration effects on clotting time and activity. Stress-hemoconcentration accounted for the majority of coagulation changes. PMID:24222908
Iron-enhanced coagulation is attenuated by chelation A thrombelastographic and ultrastructural analysis.
Nielsen, Vance G; Pretorius, Etheresia
Increased circulating ferritin and free iron have been found in a variety of disease states associated with thrombophilia. When blood or plasma is exposed to iron addition, characteristic changes in thrombus formation are observed by scanning electron microscopy, which include fusion of fibrin polymers, matting, and even sheeting of fibrin. A primary mechanism posited to explain iron-mediated hypercoagulability is hydroxyl radical formation and modification of fibrinogen; however, iron has also been demonstrated to bind to fibrinogen. We have recently demonstrated that iron enhances coagulation, manifested as a decrease in the time of onset of coagulation. Using clinically encountered concentrations of iron created by addition of FeCl3 to human plasma, we demonstrated that iron-mediated changes in reaction time determined by thrombelastography or changes in thrombus ultrastructure were significantly, but not completely, reversed by iron chelation with deferoxamine. Thus, reversible iron binding to fibrinogen mechanistically explains a significant portion of coagulation kinetic and ultrastructural hypercoagulability. Further investigation is needed to determine whether residual iron binding or other iron-mediated effects is responsible for hypercoagulability observed after chelation. PMID:24991945
Plasma surface cleaning in a microwave plasma source
C. C. Tsai; W. D. Nelson; H. H. Haselton; D. E. Schechter; L. M. Thompson; V. B. Campbell; A. L. Glover; J. M. Googin
A microwave electron cyclotron resonance (ECR) plasma source has been operated to produce reactive plasmas of oxygen and its mixture with argon. Aluminum samples (0.95 cm by 1.9 cm) were coated with thin films (<20 μm in thickness) of Shell Vitrea oil and cleaned by using such reactive plasmas. The plasma cleaning was done in discharge conditions of microwave power
Development of the selective coagulation process
Yoon, R.H.; Luttrell, G.H.
The selective hydrophobic coagulation (SHC) process is based on the recent finding that hydrophobic particles can be selectively coagulated without using traditional agglomerating agents or flocculants. The driving force for the coagulation is the attractive energy between hydrophobic surfaces, an interaction that has been overlooked in classical colloid chemistry. In most cases, selective separations can be achieved using simple pH control to disperse the mineral matter, followed by recovery of the coal coagula using techniques that take advantage of the size enlargement. In the present work, studies have been carried out to further investigate the fundamental mechanisms of the SHC process and the parameters that affect the process of separating coal from the ash-forming minerals and pyritic sulfur. Studies have included direct force measurements of the attractive interaction between model hydrophobic surfaces, in-situ measurements of the size distributions of coagula formed under a variety of operating conditions, and development of a population balance model to describe the coagulation process. An extended DLVO colloid stability model which includes a hydrophobic interaction energy term has also been developed to explain the findings obtained from the experimental studies. In addition to the fundamental studies, bench-scale process development test work has been performed to establish the best possible method of separating the coagula from dispersed mineral matter. Two types of separators, i.e., a sedimentation tank and a rotating drum screen, were examined in this study. The sedimentation tank proved to be the more efficient unit, achieving ash reductions as high as 60% in a single pass while recovering more than 90% of the combustible material. This device, which minimizes turbulence and coagula breakage, was used in subsequent test work to optimize design and operating parameters.
Arsenic removal from drinking water during coagulation
Janet G. Hering; Pen-Yuan Chen; Jennifer A. Wilkie; Menachem Elimelech
The efficiency of arsenic removal from source waters and artificial freshwaters during coagulation with ferric chloride and alum was examined in bench-scale studies. Arsenic(V) removal by either ferric chloride or alum was relatively insensitive to variations in source water composition below pH 8. At pH 8 and 9, the efficiency of arsenic(V) removal by ferric chloride was decreased in the
Landfill leachates pretreatment by coagulation-flocculation
A. Amokrane; C. Comel; J. Veron
After biological and\\/or physico-chemical treatment of stabilised landfill leachates, COD and salinity content are often larger than reject requirements. In this case, reverse osmosis can be used to treat effectively these residual COD and salinity. However, reverse osmosis feasibility is limited by the membrane fouling. In order to reduce the landfill leachates high fouling power, coagulation-flocculation is examined in this
Coagulation Factor IX for Hemophilia B Therapy?
Orlova, N. A.; Kovnir, S. V.; Vorobiev, I. I.; Gabibov, A.G.
Factor IX is a zymogen enzyme of the blood coagulation cascade. Inherited absence or deficit of the IX functional factor causes bleeding disorder hemophilia B, which requires constant protein replacement therapy. Reviewed herein are the current state in the manufacturing of FIX, improved variants of the recombinant protein for therapy, transgenic organisms for obtaining FIX, and the advances in the gene therapy of hemophilia B. PMID:22872812
Coagulation of NOM: linking character to treatment.
Sharp, E L; Parson, S A; Jefferson, B
The paper presents an overview and discussion on the link between natural organic matter (NOM) character and its treatability by coagulation. Trials were conducted on a series of bench scale and pilot plant trials on three source waters: two from UK moorland catchments and one from a US snow melt source. Overall the work demonstrates the importance of the polarity balance and the charge density of the NOM contained within the source water. The hydrophobic content controls the coagulant demand such that variation in the demand between sources or sampling periods can be accounted for by changes in the hydrophobic content and its charge density. The raw water hydrophilic content, and specifically the nonacid fraction, provides a useful indicator of the achievable residual. Analysis of coagulation performance revealed a clear relationship between zeta potential and residual DOC. For each source an operational zeta potential range exists within which the residual concentration is optimal. Comparison of the ranges achieved during each trial demonstrated that a communal range between -10 and +3 mV exist for all waters thus providing a useful guide range for operational control. PMID:16752766
Arsenic removal from drinking water during coagulation
Hering, J.G. [California Inst. of Tech., Pasadena, CA (United States); Chen, P.Y. [Industrial Technology Research Inst., Chutung Hsinchu (Taiwan, Province of China); Wilkie, J.A.; Elimelech, M. [Univ. of California, Los Angeles, CA (United States). Dept. of Civil and Environmental Engineering
The efficiency of arsenic removal from source waters and artificial freshwaters during coagulation with ferric chloride and alum was examined in bench-scale studies. Arsenic(V) removal by either ferric chloride or alum was relatively insensitive to variations in source water composition below pH 8. At pH 8 and 9, the efficiency of arsenic(V) removal by ferric chloride was decreased in the presence of natural organic matter. The pH range for arsenic(V) removal with alum was more restricted than with ferric chloride. For source waters spiked with 20 {micro}g/L arsenic(V), final dissolved arsenic(V) concentrations in the product water of less than 2 {micro}g/L were achieved with both coagulants at neutral pH. Removal of arsenic(III) from source waters by ferric chloride was both less efficient and more strongly influenced by source water composition than removal of arsenic(V). The presence of sulfate (at pH 4 and 5) and natural organic matter (at pH 4 through 9) adversely affected the efficiency of arsenic(III) removal by ferric chloride. Arsenic(III) could not be removed from source waters by coagulation with alum.
Targeted inactivation of the mouse locus encoding coagulation factor XIII-A: hemostatic abnormalities in mutant mice and characterization of the coagulation deficit.
Lauer, Peter; Metzner, Hubert J; Zettlmeissl, Gerd; Li, Meng; Smith, Austin G; Lathe, Richard; Dickneite, Gerhard
Blood coagulation factor XIII (FXIII) promotes cross-linking of fibrin during blood coagulation; impaired clot stabilization in human genetic deficiency is associated with marked pathologies of major clinical impact, including bleeding symptoms and deficient wound healing. To investigate the role of FXIII we employed homologous recombination to generate a targeted deletion of the inferred exon 7 of the FXIII-A gene. FXIII transglutaminase activity in plasma was reduced to about 50% in mice heterozygous for the mutant allele, and was abolished in homozygous null mice. Plasma fibrin gamma-dimerization was also indetectable in the homozygous deficient animals, confirming the absence of activatable FXIII. Homozygous mutant mice were fertile, although reproduction was impaired. Bleeding episodes, hematothorax, hematoperitoneum and subcutaneous hemorrhage in mutant mice were associated with reduced survival. Arrest of tail-tip bleeding in FXIII-A deficient mice was markedly and significantly delayed; replacement of mutant mice with human plasma FXIII (Fibrogammin P) restored bleeding time to within the normal range. Thrombelastography (TEG) experiments demonstrated impaired clot stabilization in FXIII-A mutant mice, replacement with human FXIII led to dose-dependent TEG normalization. The mutant mice thus reiterate some key features of the human genetic disorder: they will be valuable in assessing the role of FXIII in other associated pathologies and the development of new therapies. PMID:12529747
Intranasal exposure to amorphous nanosilica particles could activate intrinsic coagulation cascade and platelets in mice
Background Nanomaterials with particle sizes <100 nm have been already applied in various applications such as cosmetics, medicines, and foods. Therefore, ensuring the safety of nanomaterials is becoming increasingly important. Here we examined the localization and biological responses of intranasally administered amorphous nanosilica particles in mice, focusing on the coagulation system. Methods We used nanosilica particles with diameters of 30, 70, or 100 nm (nSP30, nSP70, or nSP100 respectively), and conventional microscale silica particles with diameters of 300 or 1000 nm (mSP300 or mSP1000, respectively). BALB/c mice were intranasally exposed to nSP30, nSP70, nSP100, mSP300, or mSP1000 at concentrations of 500 ?g/mouse for 7 days. After 24 hours of last administration, we performed the in vivo transmission electron microscopy analysis, hematological examination and coagulation tests. Results In vivo transmission electron microscopy analysis showed that nanosilica particles with a diameter <100 nm were absorbed through the nasal cavity and were distributed into liver and brain. Hematological examination and coagulation tests showed that platelet counts decreased and that the activated partial thromboplastin time was prolonged in nSP30 or nSP70-treated groups of mice, indicating that nanosilica particles might have activated a coagulation cascade. In addition, in in vitro activation tests of human plasma, nanosilica particles had greater potential than did conventional microscale silica particles to activate coagulation factor XII. In nanosilica-particle-treated groups, the levels of soluble CD40 ligand, and von Willebrand factor which are involved in stimulating platelets tended to slightly increase with decreasing particle size. Conclusions These results suggest that intranasally administered nanosilica particles with diameters of 30 and 70 nm could induce abnormal activation of the coagulation system through the activation of an intrinsic coagulation cascade. This study provides information to advance the development of safe and effective nanosilica particles. PMID:23958113
Hypofibrinogenemia induced by tigecycline: a potentially life-threatening coagulation disorder.
Sabanis, Nikolaos; Paschou, Eleni; Gavriilaki, Eleni; Kalaitzoglou, Asterios; Vasileiou, Sotirios
A 74-year-old female patient with end-stage renal disease, undergoing periodic hemodialysis, was hospitalized due to infection by multidrug-resistant Acinetobacter baumannii after hip replacement surgery. She was treated with tigecycline, a glycylcycline agent. Subsequently she developed coagulation disorders as substantiated by increased international normalized ratio (INR), prolonged partial thromboplastin time (aPTT), and severe hypofibrinogenemia, followed by transaminasemia, cholestasis, and anemia. Ultrasonography and computed tomography revealed no underlying pathological entities. Tigecycline was discontinued and the patient underwent daily hemodialysis and received multiple fresh frozen plasma transfusions. Additionally, she was treated with colistin. Her clinical and laboratory status improved. We suggest that patients treated with tigecycline should be monitored for changes in INR, aPTT, and fibrinogen levels to avoid severe, life-threatening coagulation disturbances. PMID:25951751
Purification of petroleum-refinery waste waters by coagulation and regeneration of the coagulant sludge
E. M. Kaliniichuk; I. A. Makarov; I. I. Vasilenko; N. A. Sukhoverkhova
1.A study has been made of the treatment of petroleum refinery wastewaters by coagulation, using a mixture of ferric sulfate and chloride obtained by chlorinating a solution of ferrous sulfate.2.The average amounts of the Fe2(SO4)3 + FeCl3 coagulant mixture used for this purpose should be in the range 64–166 mg\\/liter, or 100–250 mg\\/liter based on the initial FeSO4·7H2O.3.A flow sheet
Role of coagulation pathways and treatment with activated protein C in hyperoxic lung injury
Looney, M R; Esmon, C T; Matthay, M A
Background Activated protein C (APC) significantly decreases mortality in severe sepsis, but its role in acute lung injury from non-infectious aetiologies is unclear. The role of APC in hyperoxic acute lung injury was tested by studying the physiology of lung injury development, measurement of key coagulation proteins and treatment with murine APC (mAPC). Methods Mice were continuously exposed to >95% oxygen and lung injury was assessed by extravascular lung water, lung vascular protein permeability and alveolar fluid clearance. Coagulation proteins were measured in bronchoalveolar lavage (BAL) fluid and plasma. Recombinant mAPC was administered in preventive and treatment strategies. Results Hyperoxia produced dramatic increases in lung vascular permeability and extravascular lung water between 72 and 96 h. Lung fluid balance was also adversely affected by progressive decreases in basal and cAMP-stimulated alveolar fluid clearance. Plasma levels of APC decreased at 72 h and were 90% depleted at 96 h. There were significant increases in BAL fluid levels of thrombomodulin, thrombin-antithrombin complexes and plasminogen activator inhibitor-1 at later time points of hyperoxia. Lung thrombomodulin expression was severely decreased during late hyperoxia and plasma levels of APC were not restored by excess thrombin administration. Administration of recombinant mAPC failed to improve indices of lung injury. Conclusions Hyperoxic acute lung injury produces procoagulant changes in the lung with a decrease in plasma levels of APC due to significant endothelial dysfunction. Replacement of mAPC failed to improve lung injury. PMID:19008297
Plasma components: properties, differences, and uses.
Benjamin, Richard John; McLaughlin, Lisa Swinton
General use of plasma components includes replacement for multiple coagulation factor deficiencies, for treatment of single coagulation factor deficiencies for which a concentrate is unavailable, and as a replacement fluid used in therapeutic plasma exchange for thrombotic thrombocytopenic purpura. Four major products currently transfused are fresh-frozen plasma (FFP), plasma frozen within 24 hours of phlebotomy (FP24), cryoprecipitate-poor plasma (CPP), and thawed plasma. FP24, CPP, and thawed plasma contain decreased amounts of labile coagulation factors. Pathogen reduction technology has included solvent/detergent, methylene blue, and ultraviolet light irradiation with psoralen or riboflavin treatment and is available in Europe but not in the United States. Pathogen-reduced plasma may contain reduced levels of certain coagulant and/or anticoagulant factors compared to FFP. Clinical findings with pathogen-reduced plasma have provided an impetus to the US Food and Drug Administration to promulgate specific requirements for approval of novel plasma products, some of which may be too burdensome for the industry to readily overcome. PMID:22578375
Monte Carlo simulation of electron back diffusion in argon
NASA Astrophysics Data System (ADS)
Radmilovi?, M.; Stojanovi?, V.; Petrovi?, Z. Lj.
Monte Carlo simulation was applied to study the back-diffusion of electrons in argon at low and moderate values of E/N from 10Td to 10 kTd. Simulations were performed for gaps of 1 cm and for pressures corresponding to the breakdown voltages taken from experimental Paschen curves. Effects of inelastic collisions, ionization, reflection of electrons and anisotropic scattering as well as anisotropic initial and reflected angular distributions of electrons were included. A complete and detailed set of electron scattering cross sections that describes well electron transport in argon was used. We found a very good agreement of the results of simulations with the experimental data for well defined initial conditions, and with several models available in the literature.(A.V. Phelps and Z.LJ. Petrovi?), Plasma Sources Sci. Tehnol. 8, R21 (1999). While effect of reflection may be large, for realistic values of reflection coefficient and for realistic secondary electron productions the effect may be neglected for the accuracy required in gas discharge modeling.
Improving the efficiency of clarifiers for coagulation treatment of water
NASA Astrophysics Data System (ADS)
Vinogradov, V. N.; Smirnov, B. A.; Zhadan, A. V.; Avan, V. K.
Technological and design possibilities of improving clarifiers for coagulation treatment of water are considered. The results obtained from implementing these possibilities in real devices are presented.
Treatment of biologically treated leachate by oxidation and coagulation.
Zhang, H Y; Zhao, Y C; Qi, J Y
This work aims to investigate removal efficiency of oxidation and coagulation/flocculation processes, to provide an effective method for the treatment of biologically pre-treated leachate. Leachate containing 985 mg L(-1) COD was treated by using three treatment schemes, i.e. oxidation, coagulation/flocculation and the combined process of coagulation/flocculation followed by oxidation. The application of single oxidation resulted in the effective removal of COD and color up to 80.4 and 83.2%, respectively. However, residual COD values lower than 200 mg L(-1) could only be achieved under intensive experimental conditions (high dosage of Ca(ClO)(2) and prolonged oxidation time). Coagulation/flocculation yielded residual COD values higher than 200 mg L(-1) even at the optimum coagulation conditions. The combined treatment by coagulation/flocculation followed by oxidation yielded final COD lower than 100 mg L(-1) at the following conditions: pre-coagulation with 250 mg L(-1) PFS (poly-ferric sulfate) and over 30-min post-oxidation, or pre-coagulation with 300 mg L(-1) PFS and over 20-min post-oxidation. Hence, pre-coagulation with PFS followed by oxidation with Ca(ClO)(2) was recommended for advanced treatment of biologically treated leachate. PMID:22179637
Compound bioflocculant and polyaluminum chloride in kaolin-humic acid coagulation: factors influencing coagulation performance and floc characteristics.
Li, Ruihua; Gao, Baoyu; Huang, Xin; Dong, Hongyu; Li, Xiaochen; Yue, Qinyan; Wang, Yan; Li, Qian
The objective of this study was to investigate the influence of coagulant dosage and pH on coagulation performance and floc properties using polyaluminum chloride (PAC) and compound bioflocculant (CBF) dual-coagulant in kaolin-humic acid (HA) treatment. Results showed that as PAC dosage rose, comparatively better coagulation efficiencies and floc characteristics were achieved due to stronger charge neutralization and sweeping effect. Addition of CBF could enhance coagulation performance and floc properties, including size, strength and recoverability, except fractal dimension. Solution pH had a significant effect on coagulation efficiencies and flocs formation. Under acidic condition, flocs showed higher strength and recoverability but lower fractal dimension, where charge neutralization was the foremost mechanism. More compact flocs were generated under alkaline condition due to the sweeping effect of hydrolyzed Al species. PMID:25218625
Coagulation profile and platelet parameters of the Arabian sand gazelle (Gazella subgutturosa marica): comparison with humans and camels.
Hussein, M F; Aljumaah, R S; Homeida, A M; Alhaidary, A A; Alshaikh, M A; Gar Elnabi, A; Mohammed, O B; Omer, Sawsan A; Macasero, W V
During March 2009, we evaluated the hemostatic profile and platelet indices of 18 Arabian sand gazelles (Gazella subgutturosa marica) and compared the results with those from humans and camels (Camelus dromedarius). Gazelles and camels had shorter activated partial thromboplastin times, lower proconvertin and higher antihemophilic factor coagulation activity, and plasma fibrinogen levels than humans. Prothrombin time was longer in sand gazelles and shorter in camels than it was in humans. Plasma thromboplastin component, Stuart factor, and plasma thromboplastin antecedent were similar in gazelles, humans, and camels, whereas the platelet count of the sand gazelle was significantly higher than it was for camels and humans. PMID:20966267
Optical emission spectrometric determination of arsenic and antimony by continuous flow chemical hydride generation and a miniaturized microwave microstrip argon plasma operated inside a capillary channel in a sapphire wafer
NASA Astrophysics Data System (ADS)
Pohl, Pawel; Zapata, Israel Jimenéz; Bings, Nicolas H.; Voges, Edgar; Broekaert, José A. C.
Continuous flow chemical hydride generation coupled directly to a 40 W, atmospheric pressure, 2.45 GHz microwave microstrip Ar plasma operated inside a capillary channel in a sapphire wafer has been optimized for the emission spectrometric determination of As and Sb. The effect of the NaBH 4 concentration, the concentration of HCl, HNO 3 and H 2SO 4 used for sample acidification, the Ar flow rate, the reagent flow rates, the liquid volume in the separator as well as the presence of interfering metals such as Fe, Cu, Ni, Co, Zn, Cd, Mn, Pb and Cr, was investigated in detail. A considerable influence of Fe(III) (enhancement of up to 50 %) for As(V) and of Fe(III), Cu(II) and Cr(III) (suppression of up to 75%) as well as of Cd(II) and Mn(II) (suppression by up to 25%) for Sb(III) was found to occur, which did not change by more than a factor of 2 in the concentration range of 2-20 ?g ml - 1 . The microstrip plasma tolerated the introduction of 4.2 ml min - 1 of H 2 in the Ar working gas, which corresponded to an H 2/Ar ratio of 28%. Under these conditions, the excitation temperature as measured with Ar atom lines and the electron number density as determined from the Stark broadening of the H ? line was of the order of 5500 K and 1.50 · 10 14 cm - 3 , respectively. Detection limits (3?) of 18 ng ml - 1 for As and 31 ng ml - 1 for Sb were found and the calibration curves were linear over 2 orders of magnitude. With the procedure developed As and Sb could be determined at the 45 and 6.4 ?g ml - 1 level in a galvanic bath solution containing 2.5% of NiSO 4. Additionally, As was determined in a coal fly ash reference material (NIST SRM 1633a) with a certified concentration of As of 145 ± 15 ?g g - 1 and a value of 144 ± 4 ?g g - 1 was found.
Influence of argon and oxygen on charge-state-resolved ion energydistributions of filtered aluminum arcs
Rosen, Johanna; Anders, Andre; Mraz, Stanislav; Atiser, Adil; Schneider, Jochen M.
The charge-state-resolved ion energy distributions (IEDs) in filtered aluminum vacuum arc plasmas were measured and analyzed at different oxygen and argon pressures in the range 0.5 8.0 mTorr. A significant reduction of the ion energy was detected as the pressure was increased, most pronounced in an argon environment and for the higher charge states. The corresponding average charge state decreased from 1.87 to 1.0 with increasing pressure. The IEDs of all metal ions in oxygen were fitted with shifted Maxwellian distributions. The results show that it is possible to obtain a plasma composition with a narrow charge-state distribution as well as a narrow IED. These data may enable tailoring thin-film properties through selecting growth conditions that are characterized by predefined charge state and energy distributions.
Dust coagulation in protoplanetary disks: porosity matters
C. W. Ormel; M. Spaans; A. G. G. M. Tielens
Context: Sticking of colliding dust particles through van der Waals forces is the first stage in the grain growth process in protoplanetary disks, eventually leading to the formation of comets, asteroids and planets. A key aspect of the collisional evolution is the coupling between dust and gas motions, which depends on the internal structure (porosity) of aggregates. Aims: To quantify the importance of the internal structure on the collisional evolution of particles, and to create a new coagulation model to investigate the difference between porous and compact coagulation in the context of a turbulent protoplanetary disk. Methods: We have developed simple prescriptions for the collisional evolution of porosity of grain-aggregates in grain-grain collisions. Three regimes can then be distinguished: `hit-and-stick' at low velocities, with an increase in porosity; compaction at intermediate velocities, with a decrease of porosity; and fragmentation at high velocities. (..) Results: (..) We can discern three different stages in the particle growth process (..) We find that when compared to standard, compact models of coagulation, porous growth delays the onset of settling, because the surface area-to-mass ratio is higher, a consequence of the build-up of porosity during the initial stages. As a result, particles grow orders of magnitudes larger in mass before they rain-out to the mid-plane. Depending on the turbulent viscosity and on the position in the nebula, aggregates can grow to (porous) sizes of ~ 10 cm in a few thousand years. We also find that collisional energies are higher than in the limited PCA/CCA fractal models, thereby allowing aggregates to restructure. It is concluded that the microphysics of collisions plays a key role in the growth process.
Natural organic matter removal and enhanced coagulation as a link between coagulation and electrocoagulation
Djamel Ghernaouta; Badiaa Ghernaoutb; Amara Kellil
Although coagulation has historically been used for turbidity removal, drinking water regulations have emerged in recent years expanding the use of this process beyond its traditional role to include disinfection by-products (DBP) precursors removal. Effective removal of DBP precursors is the one of the major challenges in modern drinking water treatment. DBP precursors are present in all surface water supplies
Optimized alumina coagulants for water treatment
May D. Nyman; Thomas A. Stewart
Substitution of a single Ga-atom or single Ge-atom (GaAl.sub.12 and GeAl.sub.12 respectively) into the center of an aluminum Keggin polycation (Al.sub.13) produces an optimal water-treatment product for neutralization and coagulation of anionic contaminants in water. GaAl.sub.12 consistently shows .about.1 order of magnitude increase in pathogen reduction, compared to Al.sub.13. At a concentration of 2 ppm, GaAl.sub.12 performs equivalently to 40
Ambient non-thermal plasma for metal surface treatment
Prasad Nuamatha; Bijan Pashaie; Shirshak Dhali; Bakul Dave
Atmospheric pressure discharge in Argon\\/Hydrogen and Argon\\/Oxygen mixture is used to clean metal surfaces prior to applying coating. Dielectric barrier discharges driven by low frequency (4 kHz) and RF (13.45 MHz) are used for the treatment. Plasma treatment removes organic contaminants from the surface of the steel and could provide an alternative to chemical cleaning. Peel tests indicate that Argon\\/Hydrogen
Intense terahertz emission from atomic cluster plasma produced by intense femtosecond laser pulses
Jahangiri, Fazel; Hashida, Masaki; Tokita, Shigeki; Sakabe, Shuji [Advanced Research Center for Beam Science, ICR, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan and Department of Physics, GSS, Kyoto University, Kitashirakawa, Sakyo, Kyoto 606-7501 (Japan); Nagashima, Takeshi; Hangyo, Masanori [Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka 565-0871 (Japan)
Terahertz (THz) emission from argon cluster plasma, generated by intense femtosecond laser pulses in the energy range of 10-70 mJ, has been investigated. THz polarization, energy dependence, and angular distribution were measured to provide an initial discussion on the mechanisms of THz emission. THz pulses of much higher energy were generated from argon clusters than from argon gas, which indicates that plasma produced from atomic clusters holds considerable promise as an intense THz source.
Spectral dependence of purely-Kerr-driven filamentation in air and argon
Ettoumi, W.; Petit, Y.; Kasparian, J.; Wolf, J.-P. [Universite de Geneve, GAP-Biophotonics, 20 rue de l'Ecole de Medecine, 1211 Geneva 4 (Switzerland); Bejot, P.; Hertz, E.; Faucher, O.; Lavorel, B. [Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 5209 CNRS-Universite de Bourgogne, 9 Av. A. Savary, Boite Postale 47 870, F-21078 DIJON Cedex (France); Loriot, V. [Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 5209 CNRS-Universite de Bourgogne, 9 Av. A. Savary, Boite Postale 47 870, F-21078 DIJON Cedex (France); Instituto de Quimica Fisica Rocasolano, CSIC, C/Serrano, 119, 28006 Madrid (Spain)
Based on numerical simulations, we show that higher-order nonlinear indices (up to n{sub 8} and n{sub 10}, respectively) of air and argon have a dominant contribution to both focusing and defocusing in the self-guiding of ultrashort laser pulses over most of the spectrum. Plasma generation and filamentation are therefore decoupled. As a consequence, ultraviolet wavelength may not be the optimal wavelength for applications requiring to maximize ionization.
On the inversion mechanism in the CW argon-ion laser
V. Kitaeva; Yu. Osipov; P. Rubin; N. Sobolev
Temperatures and densities of atoms and electrons were obtained by spectroscopic methods in a gas discharge plasma used for CW ion-argon lasers. The measurements were carried out with capillaries 250-400 mm long with a bore diameter of 1.6-2.8 mm. The filling pressures were 0.2-0.7 torr and the discharge current densities 100-500 A\\/cm2. Electron temperatures were found from measured side-on widths
21 CFR 864.5425 - Multipurpose system for in vitro coagulation studies.
Code of Federal Regulations, 2012 CFR
...Multipurpose system for in vitro coagulation studies. 864.5425 Section...Multipurpose system for in vitro coagulation studies. (a) Identification...multipurpose system for in vitro coagulation studies is a device...