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Sample records for blood viscosity

  1. Cytokine modulation of human blood viscosity from vivax malaria patients.

    Science.gov (United States)

    Scherer, Edson Fredulin; Cantarini, Déborah Giovanna; Siqueira, Renan; Ribeiro, Elton Brito; Braga, Érika Martins; Honório-França, Adenilda Cristina; França, Eduardo Luzía

    2016-06-01

    Malaria is a major infectious disease in several countries and is caused by protozoa of the genus Plasmodium. In vivax malaria patients, inflammatory processes occur, as well as changes in cytokines and blood flow. The present study analyzed the cytokine modulation of blood viscosity from patients infected with Plasmodium vivax (P. vivax). Blood samples were collected from 42 non-infected individuals (control group) and 37 individuals infected with P. vivax. The IL-2, IL-4, IL-6, IL-10, TNFα, TGF-β and IL-17 cytokine concentrations in the serum were assessed, and the blood rheological properties were determined. The analysis of blood viscosity for shear rates revealed that the blood viscosity of the infected patients was significantly greater than that of the non-infected individuals. The viscosity of the blood was greater in the infected individuals than in the non-infected subjects. The serum from individuals with P. vivax infections exhibited higher IFN-γ and IL-17 concentrations and lower TGF-β levels. Incubation of the blood from infected individuals with IL-17 or IL-17 associated with IFN-γ reduced the viscosity to rates equivalent to the blood from non-infected individuals. Independently of cytokine modulation, no correlation was found between the parasitemia and blood viscosity of the infected patients. These data suggest that the alterations of blood viscosity are relevant as an auxiliary tool for the clinical diagnosis of disease. In malaria, erythrocytes are more sensitive to osmotic shock, and the reduction of viscosity by IL-17 may be related to a possible immunomodulator agent during infection.

  2. Prediction of Anomalous Blood Viscosity in Confined Shear Flow

    Science.gov (United States)

    Thiébaud, Marine; Shen, Zaiyi; Harting, Jens; Misbah, Chaouqi

    2014-06-01

    Red blood cells play a major role in body metabolism by supplying oxygen from the microvasculature to different organs and tissues. Understanding blood flow properties in microcirculation is an essential step towards elucidating fundamental and practical issues. Numerical simulations of a blood model under a confined linear shear flow reveal that confinement markedly modifies the properties of blood flow. A nontrivial spatiotemporal organization of blood elements is shown to trigger hitherto unrevealed flow properties regarding the viscosity η, namely ample oscillations of its normalized value [η]=(η-η0)/(η0ϕ) as a function of hematocrit ϕ (η0=solvent viscosity). A scaling law for the viscosity as a function of hematocrit and confinement is proposed. This finding can contribute to the conception of new strategies to efficiently detect blood disorders, via in vitro diagnosis based on confined blood rheology. It also constitutes a contribution for a fundamental understanding of rheology of confined complex fluids.

  3. Whole blood viscosity issues VI: Association with blood salicylate level and gastrointestinal bleeding

    Directory of Open Access Journals (Sweden)

    Ezekiel Uba Nwose

    2010-01-01

    Full Text Available Background : This series on whole blood viscosity issues has been trying to elucidate the sensitivity, specificity and usefulness of the laboratory parameter in clinical practice. The postulation has been that since antiplatelet is used in the management of stasis, of which blood viscosity is an index, the latter would be useful laboratory indication and/or contraindication. Aim : The aim of this study was to observe whether blood level of acetylsalicylic acid differs with the level of whole blood viscosity. Patients and Methods : Out of the ten years database, 538 cases that were concomitantly tested for haematocrit, total proteins and blood level of salicylate were selected for this study. A separate nine cases of positive faecal occult blood tests were audited for blood viscosity and reviewed. Results : A statistically significant difference is observed with lower blood viscosity being associated with higher salicylate level in comparison of the former between the highest vs. lowest quartiles (p < 0.002. This observation demonstrates the effect of aspirin in lowering blood stasis. Reviewing the positive faecal occult blood cases indicate that gastrointestinal bleeding is characterized by relative hypoviscosity and that hyperviscosity is not present during bleeding complications. Conclusion : The findings affirm that whole blood viscosity is a valid clinical laboratory parameter for evidence-based contraindication, indication and monitoring of antiplatelet medication. It calls for better appreciation and clinical utility of whole blood viscosity, which (in the absence of viscometer can now be extrapolated from haematocrit and total proteins.

  4. A memory-based model for blood viscosity

    Science.gov (United States)

    Ionescu, Clara M.

    2017-04-01

    This paper presents a comparison between existing models for non-Newtonian fluid viscosity as a function of shear rate variations. A novel model is introduced whose parameters are linked to physiological phenomena in the blood. The end use of such models is to predict changes in viscosity to adapt the speed of a nanorobot device for targeted drug delivery purposes. Simulation results show the agreement between the proposed model and available models from literature. A laboratory scale validation of the proposed model for a fluid mimicking non-Newtonian properties has been performed. Conceptual perspectives are also given in this work.

  5. EFFECT OF INCREASED WHOLE-BLOOD VISCOSITY ON REGIONAL BLOOD FLOWS IN CHRONICALLY HYPOXEMIC LAMBS

    NARCIS (Netherlands)

    DALINGHAUS, M; KNOESTER, H; GRATAMA, JWC; VANDERMEER, J; ZIJLSTRA, WG; KUIPERS, JRG

    1994-01-01

    In chronic hypoxemia blood flow and oxygen supply to vital organs are maintained, but to nonvital organs they are decreased. We measured organ blood flows (microspheres) and whole blood viscosity in 10 chronically hypoxemic lambs, with an atrial septal defect and pulmonary stenosis, and in 8 control

  6. On-line dynamic measurement of blood viscosity, hematocrit and change of blood volume

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Objective: To develop an on-line system for the measurement of blood viscosity and hematocrit. The dynamic changes of the macrovascular blood volumes,microvascular blood volumes and the total blood volume were observed by means of calculating from the testing result. Methods: Applying traditional viscosity measurement principle and specific wavelength optic density measurement method, an on-line system for the measurement of blood viscosity and hematocrit was developed, and the A/D multifunctionai board and the testing circuit were designed by ourselves. The system was validated by experiments both in vitro and in vivo. Therapeutic effects of hypertonic saline dextran solution (HSD) and Lactatic Ringer's solution at the early stage after burn-blast combined injury were compared by this method. Results: The results showed that the system has attained the goal of the design. The changes of the blood viscosity and hematocrit could be detected effectively and continuously. The changes of macrovascular, microvascular and total blood volume could be calculated approximately. Conclusions: The system and the method can continuously on-line test the blood viscosity and hematocrit, and reveal the change and distribution of blood volumes more accurately and dearly in the therapy process by estimating changes of the macrovascular, microvascular and total blood volumes, respectively. It has confirmed that HSD treatment could increase blood pressure and attenuate tissue edema by significantly increasing total blood volume,improving macrocirculatory and microcirculatory blood volumes. This study suggested that it could be desirable to develop an experiment technique based on the method mentioned above.

  7. Ultrasonic Measurement of Fluid Viscosity for Blood Characterization

    Science.gov (United States)

    Nitta, Naotaka; Homma, Kazuhiro

    2005-06-01

    Although plaque rupture in arteriosclerosis is affected by not only its strength but also by hemodynamic factors, such as blood pressure and shear stress, in particular, the viscous coefficient which directly controls the magnitude of shear stress might be a risk factor in plaque rupture. Therefore, if the viscous coefficient can be assessed noninvasively, it can be a useful index for prediction of a plaque rupture and assessment of various diseases. In this work, an ultrasonic methodology to estimate the viscous coefficient was investigated by numerical simulation and flow-phantom experiment as the fundamental investigation for noninvasively assessing the viscous characteristics of blood. These results show that the proposed method is useful for estimating the kinematic viscosity coefficient in the viscous evaluation of blood.

  8. A blood-oxygenation-dependent increase in blood viscosity due to a static magnetic field.

    Science.gov (United States)

    Yamamoto, Toru; Nagayama, Yuki; Tamura, Mamoru

    2004-07-21

    As the magnetic field of widely used MR scanners is one of the strongest magnetic fields to which people are exposed, the biological influence of the static magnetic field of MR scanners is of great concern. One magnetic interaction in biological subjects is the magnetic torque on the magnetic moment induced by biomagnetic substances. The red blood cell is a major biomagnetic substance, and the blood flow may be influenced by the magnetic field. However, the underlying mechanisms have been poorly understood. To examine the mechanisms of the magnetic influence on blood viscosity, we measured the time for blood to fall through a glass capillary inside and outside a 1.5 T MR scanner. Our in vitro results showed that the blood viscosity significantly increased in a 1.5 T MR scanner, and also clarified the mechanism of the interaction between red blood cells and the external magnetic field. Notably, the blood viscosity increased depending on blood oxygenation and the shear rate of the blood flow. Thus, our findings suggest that even a 1.5 T magnetic field may modulate blood flow.

  9. Blood viscosity monitoring during cardiopulmonary bypass based on pressure-flow characteristics of a Newtonian fluid.

    Science.gov (United States)

    Okahara, Shigeyuki; Zu Soh; Takahashi, Shinya; Sueda, Taijiro; Tsuji, Toshio

    2016-08-01

    We proposed a blood viscosity estimation method based on pressure-flow characteristics of oxygenators used during cardiopulmonary bypass (CPB) in a previous study that showed the estimated viscosity to correlate well with the measured viscosity. However, the determination of the parameters included in the method required the use of blood, thereby leading to high cost of calibration. Therefore, in this study we propose a new method to monitor blood viscosity, which approximates the pressure-flow characteristics of blood considered as a non-Newtonian fluid with characteristics of a Newtonian fluid by using the parameters derived from glycerin solution to enable ease of acquisition. Because parameters used in the estimation method are based on fluid types, bovine blood parameters were used to calculate estimated viscosity (ηe), and glycerin parameters were used to estimate deemed viscosity (ηdeem). Three samples of whole bovine blood with different hematocrit levels (21.8%, 31.0%, and 39.8%) were prepared and perfused into the oxygenator. As the temperature changed from 37 °C to 27 °C, the oxygenator mean inlet pressure and outlet pressure were recorded for flows of 2 L/min and 4 L/min, and the viscosity was estimated. The value of deemed viscosity calculated with the glycerin parameters was lower than estimated viscosity calculated with bovine blood parameters by 20-33% at 21.8% hematocrit, 12-27% at 31.0% hematocrit, and 10-15% at 39.8% hematocrit. Furthermore, deemed viscosity was lower than estimated viscosity by 10-30% at 2 L/min and 30-40% at 4 L/min. Nevertheless, estimated and deemed viscosities varied with a similar slope. Therefore, this shows that deemed viscosity achieved using glycerin parameters may be capable of successfully monitoring relative viscosity changes of blood in a perfusing oxygenator.

  10. Measurement of human blood viscosity by an electromagnetic spinning sphere viscometer.

    Science.gov (United States)

    Furukawa, Koji; Abumiya, Takeo; Sakai, Keiji; Hirano, Miki; Osanai, Toshiya; Shichinohe, Hideo; Nakayama, Naoki; Kazumata, Ken; Aida, Toshimitsu; Houkin, Kiyohiro

    2016-08-01

    We herein applied an electromagnetic spinning sphere (EMS) viscometer to the measurement of human blood viscosity for the first time. We collected blood samples from 100 healthy outpatient volunteers in order to analyse viscosity dependence on blood cell parameters and on the shear rate with a simple approximation formula [ηi (γ)\\, = Ai γ(- pi) + η0]. Viscosity dependence on blood cell parameters was relatively high at a high shear rate, but became lower as the shear rate decreased. The approximation formula with appropriate parameters of Ai and pi nearly faithfully reproduced actual blood rheological behaviour with a standard deviation of 1.5%. The distributions of Ai and pi values were broad, suggesting that the pattern of viscosity dependence on the shear rate varied with individual differences. The results obtained using the EMS viscometer suggest that blood viscosity values are individual-specific and actual individual measurements are important for understanding rheological conditions.

  11. On-line blood viscosity monitoring in vivo with a central venous catheter, using electrical impedance technique

    NARCIS (Netherlands)

    Pop, G.A.M.; Bisschops, L.L.A.; Iliev, B.; Struijk, P.C.; Hoeven, J.G. van der; Hoedemaekers, C.W.E.

    2013-01-01

    Blood viscosity is an important determinant of microvascular hemodynamics and also reflects systemic inflammation. Viscosity of blood strongly depends on the shear rate and can be characterized by a two parameter power-law model. Other major determinants of blood viscosity are hematocrit, level of i

  12. Effects of a carbohydrate-electrolyte beverage on blood viscosity after dehydration in healthy adults

    Institute of Scientific and Technical Information of China (English)

    CHANG Cui-qing; CHEN Yan-bo; CHEN Zhi-min; ZHANG Lan-tao

    2010-01-01

    Background The consumption of carbohydrate-electrolyte beverages (CEs) has been known to be more effective than plain water for recovery from dehydration. This phenomenon suggests that the ingestion of CEs after dehydration is better than water for maintaining body fluid and plasma volume, and for the recovery from hemoconcentration and high blood viscosity as well. High blood viscosity causes infarction and other cardiovascular events. In this study, CE was compared with water and tea for the ability to reduce increased blood viscosity after dehydration.Methods A crossover random control study was conducted to assess the effectiveness of three beverages for rehydration and decreasing of blood viscosity. Following exercise-induced dehydration of 2.2% of body weight in a permanent warm environment, 10 male subjects rested in a thermoneutral environment for 3 hours (rehydration period,REP). The subjects ingested test beverages equal to their body weight loss during the first 20 minutes in REP. Blood and urine samples were obtained throughout the experiments to assess the rehydration effect.rate was significantly greater for CE ((77.0+3.9)%) than water ((61.2±3.4)%) and tea ((60.5±3.7)%) for 3 hours of rest in REP.Conclusions The recovery from high blood viscosity induced by dehydration was higher with CE consumption than with water or tea. These results suggest that CE is useful for normalizing increased blood viscosity due to exercise-induced dehydration.

  13. Whole blood viscosity issues VII: the correlation with leucocytosis and implication on leukapheresis

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    Ezekiel Uba Nwose

    2010-12-01

    Full Text Available Background: Blood hyperviscosity has been acknowledged to be a complicating factor in polycythaemia and hyperproteinaemia. Hyperleucocytosis has also been implicated in hyperviscosity and may be a basis for therapeutic leukapheresis. Aims: This issue in the series seeks to determine the association and correlation between whole blood viscosity and white blood cell count (WBCC, with a view to advance the cause of a neglected clinical pathology index. Materials & Methods: Based on archived clinical pathology data, 10,857 cases that were concomitantly tested for full blood count and total proteins in the 2008 calendar year were audited for hyperleucocytosis. Whole blood viscosity level was determined and compared in the group with leucocytosis relative to the group with leucopenia and normal WBCC. The confounding effects of age, gender and red blood cell indices were evaluated. The correlation between whole blood viscosity and WBCC was also determined. Results: As a generalization, hypoviscosity is observed among individuals who presented hyperleucocytosis. There is no correlation (r = 0.20 between leucocytosis and blood viscosity. Conclusion: It is known that anaemia and thromboembolism, which can be associated with leucocytosis, predispose to hypoviscosity. The finding from this study provides evidence of association between hypoviscosity and leucocytosis. The absence of association and insignificant correlation between leucocytosis and hyperviscosity may be one explanation for ineffectiveness of therapeutic leukapheresis. Further, the non-correlation lends credence to specificity of blood viscosity, for which critical leucocytosis is not a substitute.

  14. Cocaine induces a reversible stomatocytosis of red blood cells and increases blood viscosity.

    Science.gov (United States)

    Cagienard, F; Schulzki, T; Furlong, P; Reinhart, W H

    2013-01-01

    Severe side effects of cocaine consumption are vasoocclusive events such as myocardial infarction and stroke. We have hypothesized that cocaine could affect red blood cells (RBCs) and alter the rheological behaviour of blood. Heparinized blood from healthy volunteers was incubated with a final hematocrit of 45% with increasing cocaine concentrations: 0, 10, 100, 1000, and 10'000 μmol/L plasma. Time dependence of the shape change was tested in phosphate buffered saline containing cocaine. RBCs were fixed in 1% glutaraldehyde for morphological analysis. Blood viscosity was measured with a Couette Viscometer (Contraves LS 30) at 37°C and a shear rate of 69.5 s⁻¹. RBC aggregation was assessed with a Myrenne aggregometer. Cocaine induced a dose-dependent stomatocytic shape transformation of RBCs, which was more pronounced in buffer than in plasma (plasma protein binding of the drug). Stomatocytosis occurs when a drug intercalates preferentially in the inner half of the membrane lipid bilayer. It was a time-dependent process with two components, an almost instant shape change occurring within 1 s, followed by a gradual further shape change during 10 min. Stomatocytosis was reversible by resuspension of the RBCs in cocaine-free buffer. This stomatocytic shape change increased whole blood viscosity at high shear rate from 5.69±0.31 mPa.s to 6.39±0.34 mPa.s for control and 10'000 μmol/L cocaine, respectively (p<0.01). RBC aggregation was not affected by the shape change. These effects occurred at a cocaine concentration, which is several-fold above those measured in vivo. Therefore, it is unlikely that hemorheological factors are involved in vascular events after cocaine consumption.

  15. Dynamic Behavior Analysis of the Glomerulo-Tubular Balance Mediated by the Efferent Blood Viscosity

    Science.gov (United States)

    Espinel, Andrea; Rivadeneira, Pablo S.; Costanza, Vicente; Amorena, Carlos

    In this paper, a mathematical model of the dynamics of a single-nephron function relating glomerulo-tubular balance, tubule-glomerular feedback, and peritubular blood viscosity is developed. Based upon experimental data, the model shows that complex behaviors of the nephron can be modulated by changes in the efferent arteriole blood viscosity. The main hypothesis is that the reabsorbed mass flow is modulated by the hematocrit of the efferent arteriole, in addition to the Starling forces. From a mathematical perspective, these behaviors can be explained by a bifurcation diagram analysis where the efferent blood viscosity is taken as the bifurcation parameter. This analytical description allows to predict changes in proximal convoluted tubule reabsorption, following changes in peritubular capillary viscosity generated by periodic changes in the glomerular filtration rate. Thus, the model links the tubule-glomerular feedback with the glomerular tubular balance.

  16. Whole blood viscosity is negatively associated with bone mineral density in postmenopausal women with osteoporosis.

    Science.gov (United States)

    Teng, Zong-yan; Pei, Li-chun; Zhang, Ying; Li, Ying; Wang, Rui-tao

    2013-10-01

    Osteoporosis (OP) is associated with cardiovascular disease. Moreover, osteoporosis has been shown to be an independent predictor of cardiovascular mortality. Recent studies revealed that altered blood rheology plays a critical role in atherosclerosis. A study confirmed that whole blood viscosity (WBV) is a predictor of cardiovascular events. However, little research has been conducted to investigate the relationship between blood viscosity and osteoporosis. In this cross-sectional study, we investigated the relationship between the rheological parameters and bone mineral density (BMD) in 481 subjects in the International Physical Examination and Healthy Center of the Second Affiliated Hospital, Harbin, China. Different biochemical stress and physical activity are correlated to lumbar spine BMD. Stepwise multivariate linear regression analysis revealed that WBV was a significant factor for decreased BMD (β=-0.513; Posteoporosis and negatively correlated with BMD. Further studies are warranted to investigate whether antiosteoporosis medication could normalize whole blood viscosity in postmenopausal women with osteoporosis.

  17. Fluid friction and wall viscosity of the 1D blood flow model

    CERN Document Server

    Wang, Xiao-Fei; Matsukawa, Mami; Ghigo, Arthur; Lagrée, Pierre-Yves; Fullana, Jose-Maria

    2015-01-01

    We study the behavior of the pulse waves of water into a flexible tube for application to blood flow simulations. In pulse waves both fluid friction and wall viscosity are damping factors, and difficult to evaluate separately. In this paper, the coefficients of fluid friction and wall viscosity are estimated by fitting a nonlinear 1D flow model to experimental data. In the experimental setup, a distensible tube is connected to a piston pump at one end and closed at another end. The pressure and wall displacements are measured simultaneously. A good agreement between model predictions and experiments was achieved. For amplitude decrease, the effect of wall viscosity on the pulse wave has been shown as important as that of fluid viscosity.

  18. Piezoelectric layer embedded-microdiaphragm sensors for the determination of blood viscosity and density

    Science.gov (United States)

    Kim, Hye Jin; Kim, Jinsik; Zandieh, Omid; Chae, Myung-Sic; Kim, Tae Song; Lee, Jeong Hoon; Park, Jung Ho; Kim, Seonghwan; Hwang, Kyo Seon

    2014-10-01

    We introduce a lead zirconate titanate [PZT; Pb(Zr0.52Ti0.48)O3] microdiaphragm resonating sensor packaged in a polydimethylsiloxane chip. The proposed sensor can measure the density and viscosity of a liquid that is within the density and viscosity regime of blood (1.060 × 103 kg/m3, 3-4 cP). To verify the basic characteristics of the sensor, viscous solutions were prepared from glycerol and deionized water with a density in the range from 0.998 to 1.263 × 103 kg/m3 and a viscosity in the range from 1 to 1414 cP. We measured the frequency responses of the sensor before and after injecting the viscosity- and density-controlled liquid under the bottom of the microdiaphragm. The resonant frequencies in the (1,1) and (2,2) modes decreased linearly as a function of the liquid density in the range from 0.998 to 1.146 × 103 kg/m3 with a sensitivity of 28.03 Hz/kg.m-3 and 81.85 Hz/kg.m-3, respectively. The full width at half maximum had a logarithmic relationship with the liquid viscosity in the viscosity range from 1 to 8.4 cP. The quality factor (Q-factor) for the 50% glycerol/water mixture was determined to be greater than 20 for both the (1,1) and the (2,2) modes, indicating that the microdiaphragm resonating sensor is suitable for measuring the density and viscosity of a liquid within a density range from 0.998 to 1.1466 × 103 kg/m3 and a viscosity range from 1 to 8.4 cP. These density and viscosity ranges span the regime of possible changes of blood characteristics. The microdiaphragm resonating sensors were also tested with a real human serum to verify that the sensor is suitable for measuring the viscosity and density of blood. Therefore, the PZT microdiaphragm resonating sensor could be utilized for early diagnosis of diseases associated with changes in the physical properties of blood.

  19. Whole blood viscosity assessment issues IV: Prevalence in acute phase inflammation

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    Ezekiel Uba Nwose

    2010-08-01

    Full Text Available Background: Hyperviscosity syndrome has been suggested as not simply an acute reaction. Yet, erythrocyte sedimentation rate is associated with whole blood viscosity and it is an indirect acute phase inflammation marker. Aims: This work investigates the prevalence of hyperviscosity in acute phase inflammation. Materials and Methods: Archived clinical pathology data for the period of 1999 to 2008 were utilized. 40,632-cases tested for C-reactive protein and/or erythrocyte sedimentation rate from five alternate years, which were concomitantly tested for haematocrit and total proteins, were extracted. The prevalence of abnormal viscosity associated with positive results of C-reactive protein and erythrocyte sedimentation rate were evaluated. Results: Hyperviscosity is infrequently associated with positive C-reactive protein (2.9% and erythrocyte sedimentation rate (2.7% sub-populations, and are not statistically different from their respective negative sub-populations. Normoviscosity is significantly more prevalent in the positive sub-populations (p < 0.01. Further analyses indicate that prevalence of acute phase inflammation is statistically significantly less in hyperviscosity compared to normoviscosity sub-population (p < 0.00001. Actual blood viscosity level increases with level of inflammation though. Conclusion: The study demonstrates that although blood viscosity level may increase with inflammation, hyperviscosity is not frequent in, or sensitive to acute phase inflammation. It portends that whole blood viscosity is not unspecific as acute phase inflammation markers. It calls for clinicians to consider utilizing whole blood viscosity in disease conditions where stasis is implicated, in which it is specific and valuable. It would also benefit to establish whether hyperviscosity is a chronic phase inflammation marker.

  20. On-line blood viscosity monitoring in vivo with a central venous catheter, using electrical impedance technique.

    Science.gov (United States)

    Pop, Gheorghe A M; Bisschops, Laurens L A; Iliev, Blagoy; Struijk, Pieter C; van der Hoeven, Johannes G; Hoedemaekers, Cornelia W E

    2013-03-15

    Blood viscosity is an important determinant of microvascular hemodynamics and also reflects systemic inflammation. Viscosity of blood strongly depends on the shear rate and can be characterized by a two parameter power-law model. Other major determinants of blood viscosity are hematocrit, level of inflammatory proteins and temperature. In-vitro studies have shown that these major parameters are related to the electrical impedance of blood. A special central venous catheter was developed to measure electrical impedance of blood in-vivo in the right atrium. Considering that blood viscosity plays an important role in cerebral blood flow, we investigated the feasibility to monitor blood viscosity by electrical bioimpedance in 10 patients during the first 3 days after successful resuscitation from a cardiac arrest. The blood viscosity-shear rate relationship was obtained from arterial blood samples analyzed using a standard viscosity meter. Non-linear regression analysis resulted in the following equation to estimate in-vivo blood viscosity (Viscosity(imp)) from plasma resistance (R(p)), intracellular resistance (R(i)) and blood temperature (T) as obtained from right atrium impedance measurements: Viscosity(imp)=(-15.574+15.576R(p)T)SR ((-.138RpT-.290Ri)). This model explains 89.2% (R(2)=.892) of the blood viscosity-shear rate relationship. The explained variance was similar for the non-linear regression model estimating blood viscosity from its major determinants hematocrit and the level of fibrinogen and C-reactive protein (R(2)=.884). Bland-Altman analysis showed a bias between the in-vitro viscosity measurement and the in-vivo impedance model of .04 mPa s at a shear rate of 5.5s(-1) with limits of agreement between -1.69 mPa s and 1.78 mPa s. In conclusion, this study demonstrates the proof of principle to monitor blood viscosity continuously in the human right atrium by a dedicated central venous catheter equipped with an impedance measuring device. No safety

  1. Effect of n-tyrosol on blood viscosity and platelet aggregation.

    Science.gov (United States)

    Plotnikov, M B; Chernysheva, G A; Smol'yakova, V I; Maslov, M Yu; Cherkashina, I V; Krysin, A P; Sorokina, I V; Tolstikova, T G

    2007-01-01

    Experiments on rats showed that n-tyrosol limited the increase in blood viscosity during thermal exposure at a shear rate of 5-300 sec(-1) and inhibited ADP-induced platelet aggregation. The effects of n-tyrosol are comparable to that of pentoxyphylline.

  2. Influence of total laparoscopic hysterectomy on the blood viscosity and erythrocyte immune state in patients

    Institute of Scientific and Technical Information of China (English)

    Li Lin; Hong-yan Xu

    2015-01-01

    Objective:To investigate and study the influenced state of total laparoscopic hysterectomy for the blood viscosity and erythrocyte immune state of patients.Methods:A total of 58 patients who were treated with total hysterectomy in our hospital from June 2013 to February 2015 were the study subjects, the 29 cases in the control group were treated with routine open hysterectomy operation according to the operation types, the 29 cases in the observation group were treated with laparoscopic hysterectomy operation, then the preoperative and postoperative blood viscosity and erythrocyte immune state indexes of two groups were compared.Results:The blood viscosity indexes of the observation group at different postoperative time were all lower than the indexes of the control group, the erythrocyte immune state indexes were all better than those of the control group, and the detection results of two groups at the third day after the operation were all obviously worse than those at other times, their differences were statistically significant.Conclusions:The bad influence of total laparoscopic hysterectomy for the blood viscosity and erythrocyte immune state of patients are relatively smaller, and those postoperative indexes in recovery of patients are faster.

  3. Is viscosity important in the production of blood-brain barrier disruption by intracarotid contrast media

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    Wilcox, J.; Sage, M.R.

    1984-11-01

    A canine model was used to investigate the effects of intracarotid methylglucamine iothalamate (280 mgI/ml) at different viscosities on the normal blood-brain barrier. To alter viscosity, without changing physicochemical parameters, injections were made at either 23/sup 0/C or 37/sup 0/C. The degree of blood-brain barrier damage was assessed using Evans' Blue dye as a visual marker and by contrast enhancement measured by a computed tomographic (CT) scanner. It was found that methylglucamine iothalamate caused more blood-brain barrier damage at 23/sup 0/C than at 37/sup 0/C (p<0.1). Control studies at each temperature using intracarotid injections of physiological saline showed no temperature effect (p>0.1). The implications of these findings are discussed.

  4. Effects of oxygenation and the stress hormones adrenaline and cortisol on the viscosity of blood from the trout oncorhynchus mykiss

    DEFF Research Database (Denmark)

    Sørensen, Bodil; Weber, Roy

    1995-01-01

    Although the concentrations of the stress hormones adrenaline and cortisol in rainbow trout (Oncorhynchus mykiss) blood increase upon hypoxic exposure, the combined effects of these hormones and O2 lack upon fish blood rheology have not been investigated. Deoxygenated blood taken by caudal puncture...... exhibited lower viscosities than oxygenated samples at low shear rates, whereas the opposite was true at high shear rates. However, blood from cannulated trout had similar viscosities in its deoxygenated and oxygenated states. In the deoxygenated state, addition of adrenaline lowered viscosity at low shear...... rates and increased it at high shear rates, resembling the effects of deoxygenation observed in blood taken by venepuncture. In oxygenated blood on the contrary, no marked adrenaline effects were observed. In deoxygenated blood, addition of cortisol lowered viscosity at all measured shear rates compared...

  5. Reduction of low-density lipoprotein cholesterol, plasma viscosity, and whole blood viscosity by the application of pulsed corona discharges and filtration.

    Science.gov (United States)

    Jung, Jin M; Fridman, Alexander; Cho, Daniel J; Cho, Young I

    2013-03-01

    The present study investigated the feasibility of applying pulsed corona discharges to blood plasma to reduce the viscosity of blood plasma and whole blood. Blood plasma was separated from blood cells, treated with corona discharges, and filtered before it was re-mixed with blood cells. Plasma viscosity (PV), whole blood viscosity (WBV), and low-density lipoprotein (LDL)-c concentration were measured before and after the corona treatment and filtration. Both PV and WBV increased in the case of the corona treatment only, whereas both of them decreased in the case of the corona treatment plus filtration. In particular, the LDL-c decreased in the case of the corona treatment plus filtration by 31.5% from the baseline value. The effect of the corona treatment on the reduction of the WBV was significant at low shear rates, but not at high shear rates, suggesting that the precipitation of the molecules in blood plasma by the corona treatment and subsequent removal may suppress the aggregation of erythrocytes and improve rheological properties of blood.

  6. CARDIOVASCULAR RISK ASSESSMENT AND SUPPORT TECHNIQUES Whole blood viscosity assessment issues I: Extrapolation chart and reference values

    Directory of Open Access Journals (Sweden)

    Ezekiel Uba Nwose

    2010-04-01

    Full Text Available Background: There are many different methods for the assessment of whole blood viscosity, but not every pathology unit has equipment for any of the methods. However, a validated arithmetic method exists whereby whole blood viscosity can be extrapolated from haematocrit and total serum proteins. Aims: The objective of this work is to develop an algorithm in the form of a chart by which clinicians can easily extrapolate whole blood viscosity values in their consulting rooms or on the ward. Another objective is to suggest normal, subnormal and critical reference ranges applicable to this method. Materials and Methods: Whole blood viscosity at high shear stress was determined, from various possible pairs of haematocrit and total proteins. A chart was formulated so that whole blood viscosity can be extrapolated. After determination of two standard deviations from the mean and ascertainment of symmetric distribution, normal and abnormal reference ranges were defined. Results: The clinicians’ user-friendly chart is presented. Considering presumptive lower and upper limits, the continuum of ≤14.28, 14.29 – 15.00, 15.01 – 19.01, 19.02 – 19.39 and ≥19.40 (208 Sec-1 is obtained as reference ranges for critically low, subnormal low, normal, subnormal high and critically high whole blood viscosity levels respectively. Conclusion: This article advances a validated method to provide a user-friendly chart that would enable clinicians to assess whole blood viscosity for any patients who has results for full blood count and total proteins. It would make the assessment of whole blood viscosity costless and the neglect of a known cardiovascular risk factor less excusable.

  7. Absence of association between whole blood viscosity and delirium after cardiac surgery : A case-controlled study

    NARCIS (Netherlands)

    CheheiliSobbi, Shokoufeh; van den Boogaard, Mark; Slooter, Arjen J C; van Swieten, Henry A.; Ceelen, Linda; Pop, Gheorghe; Abdo, Wilson F.; Pickkers, Peter

    2016-01-01

    Background : Delirium after cardiothoracic surgery is common and associated with impaired outcomes. Although several mechanisms have been proposed (including changes in cerebral perfusion), the pathophysiology of postoperative delirium remains unclear. Blood viscosity is related to cerebral perfusio

  8. Mathematical modelling of blood flow through a tapered overlapping stenosed artery with variable viscosity

    CERN Document Server

    Shit, G C; Sinha, A

    2012-01-01

    This paper presents a theoretical study of blood flow through a tapered and overlapping stenosed artery under the action of an externally applied magnetic field. The fluid (blood) medium is assumed to be porous in nature. The variable viscosity of blood depending on hematocrit (percentage volume of erythrocytes) is taken into account in order to improve resemblance to the real situation. The governing equation for laminar, incompressible and Newtonian fluid subject to the boundary conditions is solved by using a well known Frobenius method. The analytical expressions for velocity component, volumetric flow rate, wall shear stress and pressure gradient are obtained. The numerical values are extracted from these analytical expressions and are presented graphically. It is observed that the influence of hematocrit, magnetic field and the shape of artery have important impact on the velocity profile, pressure gradient and wall shear stress. Moreover, the effect of primary stenosis on the secondary one has been sig...

  9. Effects of a physical fitness program on memory and blood viscosity in sedentary elderly men

    Directory of Open Access Journals (Sweden)

    H.K. Antunes

    2015-01-01

    Full Text Available The aim of this study was to investigate the effects of a 6-month exercise program on cognitive function and blood viscosity in sedentary elderly men. Forty-six healthy inactive men, aged 60–75 years were randomly distributed into a control group (n=23 and an experimental group (n=23. Participants underwent blood analysis and physical and memory evaluation, before and after the 6-month program of physical exercise. The control group was instructed not to alter its everyday activities; the experimental group took part in the fitness program. The program was conducted using a cycle ergometer, 3 times per week on alternate days, with intensity and volume individualized at ventilatory threshold 1. Sessions were continuous and maximum duration was 60 min each. There was significant improvement in memory (21%; P<0.05, decreased blood viscosity (−19%; P<0.05, and higher aerobic capacity (48%; P<0.05 among participants in the experimental group compared with the control group. These data suggest that taking part in an aerobic physical fitness program at an intensity corresponding to ventilatory threshold-1 may be considered a nonmedication alternative to improve physical and cognitive function.

  10. Effect of safflower injection on lower limb fracture healing as well as blood viscosity and blood coagulation function

    Institute of Scientific and Technical Information of China (English)

    Ya-Zhong Wang; Yun Wen

    2016-01-01

    Objective:To analyze the effect of safflower injection on lower limb fracture healing as well as blood viscosity and blood coagulation function.Methods: A total of 118 patients with fracture of lower limb were randomly divided into observation group and control group (n=59), control group received conventional surgical treatment, observation group received surgery + postoperative safflower injection treatment, and then differences in serum content of bone turnover indexes and bone metabolism indexes as well as levels of thrombelastogram parameters and blood coagulation function indexes were compared between two groups after 1 month of treatment.Results:Bone turnover indexes sBAP, PINP and BGP content in serum of observation group after 1 month of treatment were higher than those of control group while sCTX, sTAP and TRAP-5b content were lower than those of control group; bone metabolism indexes Ca2+ and 25-OH-VitD content in serum were higher than those of control group while P, PTH andβ-CTX content were lower than those of control group; thrombelastogram parameters R time and K time were longer than those of control group while MA value, G value and angle level were lower than those of control group; blood coagulation function indexes PLT, FIB and D-D content in serum were lower than those of control group while PT, APTT and TT levels were higher than those of control group.Conclusions:Safflower injection can promote postoperative fracture end healing in patients with fracture of lower limb, and also plays a positive role in reducing blood viscosity and optimizing blood coagulation function.

  11. Alterations in Blood Coagulation and Viscosity Among Young Male Cigarette Smokers of Al-Jouf Region in Saudi Arabia.

    Science.gov (United States)

    Almarshad, Hassan A; Hassan, Fathelrahman M

    2016-05-01

    Hemorheology, a measure of rheological properties of blood, is often correlated with cerebral blood flow and cardiac output; an increased blood viscosity may increase the risk of thrombosis or thromboembolic events. Previous studies have reported a large variation in hemorheological properties of blood among smokers. This prompted us to conduct coagulation experiments to evaluate the effect of cigarette smoking on hematological parameters, like cell counts, and coagulation parameters among young males in Al-Jouf region, Saudi Arabia. The hematological and coagulation parameters were used to relate the changes in viscosity and coagulation to smoking. A total of 321 male participants (126 nonsmokers and 195 smokers) were enrolled into the study as randomized sample. Complete blood count was measured by hematology analyzer, and coagulation tests were performed by coagulation analyzer. Thettest analysis was performed to compare the relationships of variables between the 2 groups. The results confirmed that smoking alters some hematology parameters leading to significant deterioration in blood flow properties. Smoking also increased the hematocrit (HCT), whole blood viscosity (WBV), and plasma viscosity (PV) but decreased the international normalized ratio (INR). The decrease in INR was found to be associated with the increase in WBV, PV, and HCT. Further investigations are necessary to assess the reversibility of such changes in cessation of smoking or other elements of influence.

  12. [Hemodynamics, blood gas composition and viscosity in patients with chronic obstructive bronchitis complicated by chronic cor pulmonale].

    Science.gov (United States)

    Verbitskiĭ, O N; Buturov, I V; Purkh, T Iu; Mohamed Fadi Fanari; Paraska, V I

    2004-01-01

    Hemodynamics, external respiratory function (ERF), blood gas composition and viscosity were studied in 120 patients with chronic obstructive bronchitis at different developmental stage of cor pulmonale. In pulmonary hypertension, there were moderate ERF disorders that became more marked in the compensatory and particularly decompensatory cor pulmonale. As bronchial patency deteriorated, the index of right ventricular performance increased from 0.76+0.081 to 1.23+0.022 in the examinees. Examination of blood gas composition revealed insignificant hypoxemia in pulmonary hypertension and compensatory cor pulmonale, which progressed with decompensation of chronic cor pulmonale (CCP). As bronchial obstruction progressed, there were increases in systolic, diastolic, and mean pressure in the pulmonary artery. The viscosity of blood and plasma and the indices of red blood cell aggregation and deformability were in the normal range in pulmonary hypertension and compensatory CCP. In CCP decompensation, the viscosity of blood and plasma and the index of red blood cell aggregation were increased and the index of red blood cell deformability was decreased.

  13. PEG-albumin supraplasma expansion is due to increased vessel wall shear stress induced by blood viscosity shear thinning.

    Science.gov (United States)

    Sriram, Krishna; Tsai, Amy G; Cabrales, Pedro; Meng, Fantao; Acharya, Seetharama A; Tartakovsky, Daniel M; Intaglietta, Marcos

    2012-06-15

    We studied the extreme hemodilution to a hematocrit of 11% induced by three plasma expanders: polyethylene glycol (PEG)-conjugated albumin (PEG-Alb), 6% 70-kDa dextran, and 6% 500-kDa dextran. The experimental component of our study relied on microelectrodes and cardiac output to measure both the rheological properties of plasma-expander blood mixtures and nitric oxide (NO) bioavailability in vessel walls. The modeling component consisted of an analysis of the distribution of wall shear stress (WSS) in the microvessels. Our experiments demonstrated that plasma expansion with PEG-Alb caused a state of supraperfusion with cardiac output 40% above baseline, significantly increased NO vessel wall bioavailability, and lowered peripheral vascular resistance. We attributed this behavior to the shear thinning nature of blood and PEG-Alb mixtures. To substantiate this hypothesis, we developed a mathematical model of non-Newtonian blood flow in a vessel. Our model used the Quemada rheological constitutive relationship to express blood viscosity in terms of both hematocrit and shear rate. The model revealed that the net effect of the hemodilution induced by relatively low-viscosity shear thinning PEG-Alb plasma expanders is to reduce overall blood viscosity and to increase the WSS, thus intensifying endothelial NO production. These changes act synergistically, significantly increasing cardiac output and perfusion due to lowered overall peripheral vascular resistance.

  14. Simulation of Variable Viscosity and Jeffrey Fluid Model for Blood Flow Through a Tapered Artery with a Stenosis

    Institute of Scientific and Technical Information of China (English)

    Noreen Sher Akbar; S. Nadeem

    2012-01-01

    Non-Newtonian fluid model for blood flow through a tapered artery with a stenosis and variable viscosity by modeling blood as Jeffrey fluid has been studied in this paper. The Jeffrey fluid has two parameters, the relaxation time A1 and retardation time A2. The governing equations are simplified using the case of mild stenosis. Perturbation method is used to solve the resulting equations. The effects of non-Newtonian nature of blood on velocity profile, temperature profile, wall shear stress, shearing stress at the stenotsis throat and impedance of the artery are discussed. The results for Newtonian fluid are obtained as special case from this model.

  15. Effects of heat transfer on MHD flow of blood through an inclined porous artery with stenosis having variable viscosity

    CERN Document Server

    Tripathi, Bhavya

    2016-01-01

    In this paper, effects of heat transfer on the blood flow through a stenosed, inclined non-tapered porous artery subject to the action of external magnetic field is investigated. Viscosity is assumed as variable viscosity with variable Hematocrit throughout the region of the artery. Governing equations have been modeled by taking blood as incompressible magnetohydrodynamic (MHD) Newtonian fluid. The energy equation is formulated by taking an extra factor of the heat source in its equation. The nonlinear momentum equations are simplified under the assumption of mild stenosis. Homotopy perturbation method (HPM) is used to solve nonlinear equations of velocity and temperature profiles. Effects of porosity parameter (Z), applied magnetic field parameter (M), variable hematocrit parameter(Hr), Brinkman number (Br), heat source parameter (Q) and the Grashof number (Gr) on velocity and temperature profiles are discussed graphically.

  16. Effect of Pyramidal Training on Plasma Lipid Profile and Fibrinogen, and Blood Viscosity of Untrained Young Men

    Directory of Open Access Journals (Sweden)

    Abbass Ghanbari-Niaki

    2013-09-01

    Full Text Available The present study examined the effects of progressive exercise (pyramidal short-term program on plasma fibrinogen, lipid profile and blood viscosity in untrained young men. Changes and imbalances in homeostasis lead to cause of heart attacks. There is conflicting information about the effect of exercise on these factors. 19 young healthy untrained men were randomly assigned to the exercise group (n = 10 and controls (n = 9 groups. Exercise training group with increasing severity of heart maximum 25 to 100 percent began to run the practice (pyramid in 42-minute sessions, 3 times a week, for 4 weeks. There was no significant difference between the parameters of body composition, control, and training groups. Levels of total cholesterol and low density lipoprotein density and viscosity of the blood significantly decreased in the training group compared with the control group (p value, respectively is 0.001, 0.001 and 0.035. The changes in the concentration of fibrinogen, high-density lipoprotein and triglycerides in both groups are not significant in both groups (p value, respectively is 0.645, 0.993 and 0.421. The present results show that it is possible that progressive training (pyramidal short-term program changed the levels of cardiovascular risk factors by reducing blood viscosity.

  17. About a mechanism of the influence of shear stress for viscosity of the blood in vessels of small diameter

    Directory of Open Access Journals (Sweden)

    Лев Николаевич Катюхин

    2014-12-01

    Full Text Available It is proposed a physiological and experimentally confirmed explanation of Fåhraeus-Lindqvist-effect in capillaries using the profile analyses of osmotic deformability of red blood cells. It was shown the dose-dependent change of the erythrocytes deformability in the stage of isotropic spheres after forming artificial water pores (nystatin and occlusion (PbCl2 of available pores. The Sigma-effect reducing of hematocrit and viscosity in a shear flow of blood through the vessels of a small diameter was conditioned by the interchange of liquid phase between the erythrocyte and the plasma.

  18. Effect of heparin in combined with magnesium sulfate on the blood gas and blood viscosity in patients with pulmonary heart failure

    Institute of Scientific and Technical Information of China (English)

    Rui Deng; Hong-Wei Liang; Jun-Hong Liao; Jun-Hua Chen; Hai-Yan Liu

    2016-01-01

    Objective:To observe the effect of heparin in combined with magnesium sulfate on the blood gas indicators and blood viscosity in patients with pulmonary heart disease merged with respiratory failure.Methods: A total of 80 patients with pulmonary heart disease merged with respiratory failure who were admitted in our hospital were included in the study and randomized into the observation group (n=40) and the control group (n=40). The patients in the control group were given routine symptomatic treatments of pulmonary heart disease. On the above basis, the patients in the observation group were given intravenous drip of heparin and magnesium sulfate. The patients in the two groups were treated for 2 weeks. The blood gas indicators, blood viscosity indicators, PAPs, SBP, and DBP in the two groups were compared. The clinical efficacy in the two groups was evaluated.Results:After 2-week treatment, PaO2 and PaCO2 in the two groups were improved, pH value was not significantly changed, PaO2 in the observation group was significantly higher than that in the control group, while PaCO2 was significantly lower than that in the control group. The hemorheology indicators after treatment in the two groups were significantly reduced when compared with before treatment, among which the comparison of WBV, PV, Hct, and EAI between the two groups was statistically significant, and PAPs after treatment in the observation group was significantly reduced when compared with the control group. SBP and DBP after treatment in the two groups were not significantly changed.Conclusions: Heparin in combined with magnesium sulfate in the treatment of pulmonary heart disease merged with respiratory failure can improve the blood gas indicators and blood viscosity indicators, and reduce SBP of pulmonary artery, with a higher efficacy; therefore, it deserves to be widely recommended in the clinic.

  19. Which side of the balance determines the frequency of vaso-occlusive crises in children with sickle cell anemia: Blood viscosity or microvascular dysfunction?

    Science.gov (United States)

    Charlot, Keyne; Romana, Marc; Moeckesch, Berenike; Jumet, Stéphane; Waltz, Xavier; Divialle-Doumdo, Lydia; Hardy-Dessources, Marie-Dominique; Petras, Marie; Tressières, Benoît; Tarer, Vanessa; Hue, Olivier; Etienne-Julan, Maryse; Antoine-Jonville, Sophie; Connes, Philippe

    2016-01-01

    Vascular resistance and tissue perfusion may be both affected by impaired vascular function and increased blood viscosity. Little is known about the effects of vascular function on the occurrence of painful vaso-occlusive crises (VOC) in children with sickle cell anemia (SCA). The aim of the present study was to determine which side of the balance (blood viscosity or vascular function) is the most deleterious in SCA and increases the risk for frequent hospitalized VOC. Microvascular function, microcirculatory oxygenation and blood viscosity were determined in a group of 22 SCA children/adolescents at steady state and a group of 13 healthy children/adolescents. Univariate analyses demonstrated blunted microvascular reactivity during local thermal heating test and decreased microcirculatory oxygenation in SCA children compared to controls. Multivariate analysis revealed that increased blood viscosity and decreased microcirculatory oxygenation were independent risk factors of frequent VOC in SCA. In contrast, the level of microvascular dysfunction does not predict VOC rate. In conclusion, increased blood viscosity is usually well supported in healthy individuals where vascular function is not impaired. However, in the context of SCA, microvascular function is impaired and any increase of blood viscosity or decrease in microcirculatory oxygenation would increase the risks for frequent VOC.

  20. Effect of salvianolate combined with meglumine adenosine cyclphosphate on blood viscosity, inflammatory factors and NT-proBNP in angina pectoris patients after PCI

    Institute of Scientific and Technical Information of China (English)

    Jing Peng; Li Chen

    2016-01-01

    Objective:To study the effect of salvianolate combined with meglumine adenosine cyclphosphate on blood viscosity, inflammatory factors and NT-proBNP in angina pectoris patients after percutaneous coronary intervention (PCI).Methods:A total of 130 angina pectoris patients who received PCI treatment in our hospital from May 2012 to October 2015 were selected for study, patients' medical records were retrospectively analyzed, they were divided into the experimental group and the control group based on the different medication schemes after PCI, experimental group received routine treatment combined with salvianolate and meglumine adenosine cyclphosphate treatment after operation, and control group received conventional medical treatment after operation. The changes of perioperative blood viscosity, inflammatory factor and NT-proBNP content were compared between two groups.Results:After PCI, the blood viscosity indexes as well as inflammatory factor and NT-proBNP levels of experimental group were significantly lower than those before PCI (P0.05), inflammatory factor and NT-proBNP levels were significantly lower than those before PCI (P<0.05); 7 days after PCI, the high-shear whole blood viscosity, low-shear whole blood viscosity, plasma viscosity and aggregation index as well as TNF-α, sICAM-1, sVCAM-1, LP-PLA2, NT-proBNP, D-dimer and PTEN levels of experimental group were significantly lower than those of control group (P<0.05).Conclusions: Salvianolate combined with meglumine adenosine cyclphosphate can reduce the blood viscosity of patients with angina pectoris after PCI, and can also reduce inflammation and improve heart pump function.

  1. Heat transfer analysis on peristaltically induced motion of particle-fluid suspension with variable viscosity: Clot blood model.

    Science.gov (United States)

    Bhatti, M M; Zeeshan, A; Ellahi, R

    2016-12-01

    In this article, heat transfer analysis on clot blood model of the particle-fluid suspension through a non-uniform annulus has been investigated. The blood propagating along the whole length of the annulus was induced by peristaltic motion. The effects of variable viscosity and slip condition are also taken into account. The governing flow problem is modeled using lubrication approach by taking the assumption of long wavelength and creeping flow regime. The resulting equation for fluid phase and particle phase is solved analytically and closed form solutions are obtained. The physical impact of all the emerging parameters is discussed mathematically and graphically. Particularly, we considered the effects of particle volume fraction, slip parameter, the maximum height of clot, viscosity parameter, average volume flow rate, Prandtl number, Eckert number and fluid parameter on temperature profile, pressure rise and friction forces for outer and inner tube. Numerical computations have been used to determine the behavior of pressure rise and friction along the whole length of the annulus. The present study is also presented for an endoscope as a special case of our study. It is observed that greater influence of clot tends to rise the pressure rise significantly. It is also found that temperature profile increases due to the enhancement in Prandtl number, Eckert number, and fluid parameter. The present study reveals that friction forces for outer tube have higher magnitude as compared to the friction forces for an inner tube. In fact, the results for present study can also be reduced to the Newtonian fluid by taking ζ → ∞.

  2. Viscosity-adjusted estimation of pressure head and pump flow with quasi-pulsatile modulation of rotary blood pump for a total artificial heart.

    Science.gov (United States)

    Yurimoto, Terumi; Hara, Shintaro; Isoyama, Takashi; Saito, Itsuro; Ono, Toshiya; Abe, Yusuke

    2016-09-01

    Estimation of pressure and flow has been an important subject for developing implantable artificial hearts. To realize real-time viscosity-adjusted estimation of pressure head and pump flow for a total artificial heart, we propose the table estimation method with quasi-pulsatile modulation of rotary blood pump in which systolic high flow and diastolic low flow phased are generated. The table estimation method utilizes three kinds of tables: viscosity, pressure and flow tables. Viscosity is estimated from the characteristic that differential value in motor speed between systolic and diastolic phases varies depending on viscosity. Potential of this estimation method was investigated using mock circulation system. Glycerin solution diluted with salty water was used to adjust viscosity of fluid. In verification of this method using continuous flow data, fairly good estimation could be possible when differential pulse width modulation (PWM) value of the motor between systolic and diastolic phases was high. In estimation under quasi-pulsatile condition, inertia correction was provided and fairly good estimation was possible when the differential PWM value was high, which was not different from the verification results using continuous flow data. In the experiment of real-time estimation applying moving average method to the estimated viscosity, fair estimation could be possible when the differential PWM value was high, showing that real-time viscosity-adjusted estimation of pressure head and pump flow would be possible with this novel estimation method when the differential PWM value would be set high.

  3. Association of Whole Blood Viscosity With Metabolic Syndrome in Type 2 Diabetic Patients: Independent Association With Post-Breakfast Triglyceridemia

    Science.gov (United States)

    Minato, Satomi; Takenouchi, Akiko; Uchida, Junko; Tsuboi, Ayaka; Kurata, Miki; Fukuo, Keisuke; Kazumi, Tsutomu

    2017-01-01

    Background Associations of whole blood viscosity (WBV) with metabolic syndrome (MS) have not been extensively studied in patients with type 2 diabetes. Methods Intrapersonal means of 12 measurements of waist circumference, blood pressure (BP) and high-density lipoprotein cholesterol and those of six measurements of fasting and post-breakfast triglycerides (TG) during 12 months were calculated in a cohort of 168 patients with type 2 diabetes. Based on these means, MS was diagnosed according to the modified National Cholesterol Education Program Adult Treatment Panel III criteria with the Asian definition of abdominal obesity. WBV was calculated from hematocrit and total serum protein concentrations by a validated formula. Results Diabetes patients with MS (n = 77) had higher WBV as compared to those without MS (6.38 ± 0.06 vs. 6.10 ± 0.07 cP, P = 0.004). As the number of MS components increased, WBV increased (component number 1: 6.12 ± 0.10, 2: 6.09 ± 0.10, 3: 6.37 ± 0.08, 4: 6.42 ± 0.10, 5: 6.30 ± 0.15 cP, P for trends = 0.001). Multiple regression analysis revealed that male gender, diastolic BP and post-breakfast TG were determinants of WBV independent of fasting TG, body mass index (BMI) and waist circumference (R2 = 0.258). Conclusions Both the presence of MS and the number of MS components were associated with higher WBV in patients with type 2 diabetes. Physicians need to perform a close follow-up of type 2 diabetes patients with MS on inhibitors of sodium-glucose co-transporters 2, which may increase stroke risk associated with an increase in hematocrit and therefore blood viscosity. Post-breakfast TG was an independent determinant of WBV. Elevated WBV may represent an important confounder of the relationship between MS, postprandial hyperlipidemia and elevated cardiovascular risk in this population. PMID:28270893

  4. Noninvasive average flow estimation for an implantable rotary blood pump: a new algorithm incorporating the role of blood viscosity.

    Science.gov (United States)

    Malagutti, Nicolò; Karantonis, Dean M; Cloherty, Shaun L; Ayre, Peter J; Mason, David G; Salamonsen, Robert F; Lovell, Nigel H

    2007-01-01

    The effect of blood hematocrit (HCT) on a noninvasive flow estimation algorithm was examined in a centrifugal implantable rotary blood pump (iRBP) used for ventricular assistance. An average flow estimator, based on three parameters, input electrical power, pump speed, and HCT, was developed. Data were collected in a mock loop under steady flow conditions for a variety of pump operating points and for various HCT levels. Analysis was performed using three-dimensional polynomial surfaces to fit the collected data for each different HCT level. The polynomial coefficients of the surfaces were then analyzed as a function of HCT. Linear correlations between estimated and measured pump flow over a flow range from 1.0 to 7.5 L/min resulted in a slope of 1.024 L/min (R2=0.9805). Early patient data tested against the estimator have shown promising consistency, suggesting that consideration of HCT can improve the accuracy of existing flow estimation algorithms.

  5. Development of a Comprehensive Model of the Apparent Viscosity of Blood for Simulations of the Microcirculation in Rat Spinotrapezius Muscle Fascia

    Science.gov (United States)

    Jacobitz, Frank; Porterfield, Colin; Engebrecht, Cheryn; Metzger, Ian

    2007-11-01

    A more comprehensive model for the apparent viscosity of blood is proposed and applied to simulations of the microcirculation in rat spinotrapezius muscle fascia. At the microcirculatory level, the apparent viscosity of blood depends on the local vessel diameter, hematocrit, and shear rate. Starting with the apparent viscosity model proposed by Pries, Secomb, Gaehtgens, and Gross (Circulation Research, 67, 826-834, 1990), describing the effect of vessel diameter and hematocrit on the apparent viscosity, and using experimental data presented by Lipowsky, Usami, and Chien (Microvascular Research, 19, 297-319, 1980), describing the shear rate dependence of apparent viscosity, a more comprehensive model is developed. This model is applied to simulations of the microcirculation in rat spinotrapezius muscle fascia. The simulations use realistic vessel topology for the microvasculature, reconstructed from microscope images of tissue samples, and consider passive and active vessel properties. The numerical method is based on a Hagen-Poiseuille balance in the microvessels and a sparse matrix solver is used to obtain the solution. It was found, for example, that the distribution of vessel length follows a log-normal law. The distribution of hematocrit, however, was found to be approximately normal.

  6. Influence of blood viscosity on circulatory parameters determined by first-pass radionuclide angiocardiography in cor pulmonale

    Energy Technology Data Exchange (ETDEWEB)

    Zambo, K. [Dept. of Nuclear Medicine, Pecs (Hungary); Toth, K. [Dept. of Medicine, Div. of Cardiology Univ. Medical School, Pecs (Hungary)

    1993-12-01

    First-pass radionuclide angiocardiography (FPRNA) with {sup 99m}Tc-albumin was performed in 19 patients with cor pulmonale. Pulmonary circulation time (PCT), mean transit time (MTT), pulmonary stagnation index (PSI) were calculated from the time-activity curves for the estimation of cardiopulmonary circulation. Whole blood viscosity (WBV), plasma viscosity (PV) and hematocrit (HTC) were also measured on the same day. Significant prolongation of all parameters was observed (WBW: 5,04{+-}1.19 mPAS; PV: 1,36{+-}0,17 mPAS; HTC: 47,6{+-}2,37%; PCT: 7,10{+-}2,15 s; MTT: 9,33{+-}4,11 s; PSI: 1,30{+-}0,37) in patients with cor pulmonale. Significant positive correlations were found between PCT and WBV (r=0,552; 0,001

  7. Novel measurement of blood velocity profile using translating-stage optical method and theoretical modeling based on non-Newtonian viscosity model

    Science.gov (United States)

    Kim, Chang-Beom; Lim, Jaeho; Hong, Hyobong; Kresh, J. Yasha; Wootton, David M.

    2015-07-01

    Detailed knowledge of the blood velocity distribution over the cross-sectional area of a microvessel is important for several reasons: (1) Information about the flow field velocity gradients can suggest an adequate description of blood flow. (2) Transport of blood components is determined by the velocity profiles and the concentration of the cells over the cross-sectional area. (3) The velocity profile is required to investigate volume flow rate as well as wall shear rate and shear stress which are important parameters in describing the interaction between blood cells and the vessel wall. The present study shows the accurate measurement of non-Newtonian blood velocity profiles at different shear rates in a microchannel using a novel translating-stage optical method. Newtonian fluid velocity profile has been well known to be a parabola, but blood is a non-Newtonian fluid which has a plug flow region at the centerline due to yield shear stress and has different viscosities depending on shear rates. The experimental results were compared at the same flow conditions with the theoretical flow equations derived from Casson non-Newtonian viscosity model in a rectangular capillary tube. And accurate wall shear rate and shear stress were estimated for different flow rates based on these velocity profiles. Also the velocity profiles were modeled and compared with parabolic profiles, concluding that the wall shear rates were at least 1.46-3.94 times higher than parabolic distribution for the same volume flow rate.

  8. Effect of Xinfuning V combined with western medicine therapy on serum blood viscosity, lipid metabolism and plaque stability in patients with coronary heart disease and angina pectoris

    Institute of Scientific and Technical Information of China (English)

    Guo-Feng Ma; Xiang-Yang Wu; Ya-Ning Wang; Jun-De Li

    2016-01-01

    Objective:To analyze the effect of Xinfuning V combined with western medicine therapy on serum blood viscosity, lipid metabolism and plaque stability in patients with coronary heart disease and angina pectoris.Methods: A total of 200 patients with coronary heart disease and angina pectoris were randomly divided into observation group and control group (n=100), control group received routine western medicine therapy, observation group received routine western medicine treatment + adjuvant Xinfuning V treatment, and then the differences in with serum blood viscosity, lipid metabolism, plaque stability parameters, etc were compared between the two groups after treatment.Results: The whole blood viscosity under different shear rate (1/s, 5/s, 30/s and 200/s), plasma viscosity and fibrinogen content in peripheral blood of observation group after 4 weeks of treatment were significantly lower than those of control group; lipid metabolism indexes TC, TG, LDL-C and ApoB content in serum were lower than those of control group while HDL-C content was higher than that of control group; inflammatory factors Lp-PLA2, sICAM-1, NF-κB, hs-CRP and TNF-α content in serum were lower than those of control group; plaque stability parameters AT, TTP, mTT, PI, BI and EI levels were significantly lower than those of control group.Conclusions:Xinfuning V combined with western medicine therapy can optimize the circulating internal environment in patients with coronary heart disease and angina pectoris, and also has a remarkable effect on stabilizing plaque properties.

  9. The Effect of Organic Acid and Desiccated Ox Bile Supplementation on Performance, Fat Digestibility, Blood Metabolites and Ileal Digesta Viscosity of Broiler Chickens Fed Tallow

    Directory of Open Access Journals (Sweden)

    M. Alzawqari

    2013-08-01

    Full Text Available In order to study the effect of different levels of desiccated ox bile (DOB; 0.00, 0.25, and 0.50% and organic acid (OA; 0.00, 0.15, and 0.30% of the diet on performance, fat digestibility, blood metabolites and ileal digesta viscosity in broiler chickens fed diets containing 5% tallow, in a completely randomized design with a 3×3 factorial arrangement and 4 replicates in each treatment, 360 day-old Ross male broiler chickens were used. The isocaloric and isonitrogenous starter and grower diets were fed ad libitum to chickens from 0-21 and 21-42 days of age, respectively. Feed intake (FI, body weight gains (BWG, and feed conversion ratio (FCR was measured for starter (7-21d and grower periods (21-42 days of age. Chromic oxide at the rate of 3 g/kg was added to experimental diets to determine fat digestibility at 19-21 and 40-42 days of age. Serum cholesterol (Chol, triglyceride (TG, high density lipoprotein (HDL, low density lipoprotein (LDL and ileal digesta viscosity were measured at 21 and 42 days of age. Addition of DOB significantly increased BWG during 7 to 42d of age and FCR during 7 to 21 was improved. Although fat digestibility significantly increased by supplemental 0.50% DOB and 0.15% OA in the starter period, no interaction was observed between dietary DOB and OA for these parameters. Dietary OA had no effect on blood parameters, but supplemental 0.50% DOB significantly increased blood chemistry. Interaction between DOB and OA showed an increasing effect in Chol and TG at 42 days of age. Digesta viscosity was remained unchanged by dietary treatments. The results of this study indicated that supplementation of DOB in the diet significantly increased BWG and measured blood metabolites. Dietary supplementation of DOB increased fat digestibility of the birds fed diet containing 5% tallow.

  10. Effect of corn replacement with graded levels of wheat screening and enzyme supplementation on performance, blood lipids, viscosity and jejunal histomorphology of finisher broilers

    Energy Technology Data Exchange (ETDEWEB)

    Mazhari, M.; Golian, A.; Kermanshahi, H.

    2015-07-01

    An experiment was carried out to study the effect of corn replacement with five levels of wheat screening (0, 150, 300, 450 and 600 g/kg of diet) with (0.5 g/kg of diet) or without xylanase-glucanase enzyme on performance, blood lipids, viscosity and jejunal histomorphology of finisher broilers (25-42 days of age). Five hundred day-old Ross-308 male broiler chicks were fed by a standard commercial diet up to 24 days of age, then randomly assigned to 10 diets. Each diet was fed to five groups of ten chicks each. There was not significant differences in body weight gain (BWG), feed intake, and feed conversion ratio of birds fed with different levels of wheat screening (WS), whereas enzyme increased (p<0.05) BWG. Different levels of WS and enzyme did not have a significant effect on relative weights of carcass, breast, thigh, and abdominal fat of broilers. Relative weights of gizzard, pancreas, small and large intestine, and relative length of jejunum and jejunal and ileal viscosity were increased (p<0.05) by WS, while were decreased (p<0.05) by enzyme. The serum cholesterol level decreased (p<0.05) by increasing levels of WS. Jejunal histomorphological observations showed (p<0.05) shorter and thicker villus and lower crypt depth by increasing levels of WS, while addition of enzyme to the diets, affected (p<0.05) reversely to these parameters. The results showed that the addition of wheat screening up to an inclusion level of 600 g/kg of diet had no adverse effect on broiler performance in the finisher (25-42 d) phases whereas decreased serum cholesterol levels, increased viscosity and villus atrophy. The dietary administration of exogenous enzyme improved performance parameters and decreased viscosity and villus atrophy of broiler jejunum. (Author)

  11. Plasma Viscosity : A Risk Factor In Hypertension

    Directory of Open Access Journals (Sweden)

    Puniyani R. R

    1989-01-01

    Full Text Available Haemorrheological study on hypertension was done at Indian Institute of Technology Hospital, Bombay. Male population in the age groups of 35 to 60 years was screened for hypertension from February 1986 to February 1987. Out of 340 subjects examined, 44 hypertensive cases were found, who were investigated for blood viscosity profile and were compared with 45 controls. The parameters studied were plasma viscosity, whole blood viscosity, red cell aggregation, red cell deformability and haematocrit W.H.O. criteria of hypertension (HT was strictly adhered to (B.P. above 160/95 mm of Hg. When compared to control group, plasma viscosity and whole blood viscosity were elevated in freshly detected and uncontrolled hypertensives. Red cell aggregation and deformability were significantly altered in chronic hypertensives than in normal, but haematocrit was not affected in any group.

  12. The value of blood rheology in the blood viscosity syndrome of neonatal red blood cell%血液流变学在新生儿红细胞增多血液粘滞综合征中的价值分析

    Institute of Scientific and Technical Information of China (English)

    施欣

    2016-01-01

    目的:分析血液流变学在新生儿红细胞增多血液粘滞综合征中的应用价值。方法选取某院2014年1月至2016年1月降生的30例红细胞增多血液粘滞综合征患者作为研究组,另选同期30例健康新生儿作为对照组,在征得新生儿家属知情同意下对其血液流变学进行检测及比较。结果研究组患儿血液流变学各项指标与对照组相比较,差异具有统计学意义(P <0.05)。结论血液流变学可作为新生儿红细胞增多血液粘滞综合征的监测指标,值得在临床积极推广使用。%Objective to analyze the application value of blood rheology in the blood viscosity syndrome of neonatal red blood cells.Methods select a hospital in January 2014 to 2016 in January was born of 30 cases of red cells increased blood viscosity syndrome patients as study group, over the same period, 30 cases of healthy newborns as control group, with the consent of the relatives of newborn informed consent on the hemorheology were detected and compared.Results compared with the control group, the changes of Hemorheology in the study group were statistically significant (P< 0.05).Conclusion the blood rheology can be used as the monitoring index of the blood viscosity syndrome of neonatal red blood cells, and it is worth to be popularized and used in clinic.

  13. 老年直肠癌患者静脉麻醉期血液粘度变化的临床观察%Blood viscosity in elderly patients with colorectal cancer during venous anesthesia

    Institute of Scientific and Technical Information of China (English)

    陈涛; 钟庆; 张英; 刘玉林; 王春艳; 雷贤英; 唐显玲

    2011-01-01

    Objective To observe the changes of blood viscosity during anesthesia in elderly patients with colorectal cancer. Methods 25 patients (age ≥65 years old, n=25, ASA Ⅰ- Ⅱ ) scheduled for elective radical surgery for colorectal cancer under general anesthesia, without diseases affecting the blood viscosity such as hypertension, coronary heart disease and diabetes were enrolled. All patients received the same propofol venous anesthesia. Blood samples were taken at 4 different time points, T0, prior to the infusion and induction of anesthesia; T1, anesthesia reaching a steady state (BIS 40-60 and maintained 1 hour) after intubations; T2, 10min before the end of operation; T3, into the PACU 30 minutes. 5mi bloods were taken from elbow vein used for the hemorheological measurements within 4 hours. Blood viscosity was determined with the automatic reological examining machine. Results Compared with T0, all whole blood viscosity (Hηb, Mηb and Lηb) significantly declined at T1 (P<0. 05), and continued decrease at T2 (P<0.05). At T3, these parameters began to ascend, but still lower than T0 (P<0. 05). In particular, T1 of ηP was markedly higher than T0 (P< 0. 05). Conclusions The blood viscosity decreased significantly in elderly patients after propofol intravenous anesthesia, but increased in early stage in postoperative period.%目的 观察老年直肠癌患者在丙泊酚静脉麻醉下的血液粘度变化.方法 选择拟在全身麻醉下实施择期直肠癌根治手术,ASA Ⅰ~Ⅱ级,无合并高血压、冠心病、糖尿病等影响血液粘度疾病的老年患者25例.所有患者均采用丙泊酚静脉麻醉,分别在麻醉输液前(T0)、麻醉诱导插管后,BIS达到40~60并维持1 h(T1),手术结束前10 min(T2)、术毕拔管患者入PACU后30 min(T3)四个时点经肘静脉各采血5ml,检测高切全血粘度(Hηb)、中切全血粘度(Mηb)、低切全血粘度(Lηb)、血浆粘度(ηP).结果 全血粘度指标(Hηb、Mηb、Lηb

  14. 血液黏滞系数对颅内大型动脉瘤剪切力的影响%Impact of blood viscosity on wall shear stress of large intracranial aneurysms

    Institute of Scientific and Technical Information of China (English)

    吴京; 刘爱华; 赵艺; 符策基; 彭汤明; 钱增辉; 康慧斌; 吴中学

    2015-01-01

    Objective To simulate the computational hemodynamics of large intracranial aneurysms and analyze the impact of blood viscosity on wall shear stress.Methods Eight large intracranial aneurysms at internal carotid artery between June 2013 and July 2013 were studied retrospectively.Among them,3 aneurysms were ruptured and 5 were unruptured.Pulsatile CFD simulations were carried out using three levels of blood viscosity (0.002,0.004,0.012 Pa·s).For each aneurysm model,the average wall shear stress (WSS) predicted by the three blood viscosity levels were compared.Results Blood viscosity has significant impaction on average wall shear stress of intracranial aneurysms and parent artery.Average wall shear stress increased significantly with the increase of blood viscosity.When blood viscosity was 0.002,0.004,0.012 Pa·s,the average wall shear stress of aneurysms was (2.79 ±2.23),(5.27 ±3.72) and (11.05 ± 7.56) Pa,respectively.The average wall shear stress of parent artery was (5.61 ± 2.59),(9.56 ± 3.74) and (22.56 ± 12.41) Pa respectively.A reduction in wall shear stress between the parent artery and the aneurysm sac was found in all the cases.Conclusion Abnormal increase or decrease in blood viscosity may aggravate vascular wall damage and increase the risk of aneurysmal rupture.It is necessary to adopt patient-specific value of blood viscosity in future hemodynamic studies of intracranial aneurysms.%目的 应用血流动力学数值模拟技术分析不同血液黏滞系数对颅内大型动脉瘤剪切力水平的影响.方法 收集我院2013年6月至2013年7月收治的8例颅内大型囊性动脉瘤患者脑血管三维影像数据,其中破裂动脉瘤3例,未破裂动脉瘤5例.应用CFD ICEM软件对动脉瘤三维模型进行网格划分,再进行流体力学数值模拟计算.在血液黏滞系数为0.002、0.004和0.012 Pa·s 3种水平时对颅内大型动脉瘤进行血流动力学数值模拟运算并比较动脉瘤及载

  15. Optical viscosity sensor

    Science.gov (United States)

    Chang, Cheng-Ling; Peyroux, Juliette; Perez, Alex; Tsui, Chi-Leung; Wang, Wei-Chih

    2009-03-01

    Viscosity measurement by bend loss of fiber is presented. The sensing principle makes use of the damping characteristic of a vibrating optical fiber probe with fix-free end configuration. By measuring the displacement of the fiber probe, the viscosity can be determined by matching the probe's displacement with the displacement built in the database obtained by either experimental method or Finite element calculation. Experimental results are presented by measuring the sucrose and glycerol solutions of different concentrations with a viscosity varying from 1 to 15 cP. Stokes' flow assumption is utilized to attenuate the mass density effect and simplify the viscosity measurement.

  16. Radiative Bulk Viscosity

    CERN Document Server

    Chen, X

    2001-01-01

    Viscous resistance to changes in the volume of a gas arises when different degrees of freedom have different relaxation times. Collisions tend to oppose the resulting departures from equilibrium and, in so doing, generate entropy. Even for a classical gas of hard spheres, when the mean free paths or mean flight times of constituent particles are long, we find a nonvanishing bulk viscosity. Here we apply a method recently used to uncover this result for a classical rarefied gas to radiative transfer theory and derive an expression for the radiative stress tensor for a gray medium with absorption and Thomson scattering. We determine the transport coefficients through the calculation of the comoving entropy generation. When scattering dominates absorption, the bulk viscosity becomes much larger than either the shear viscosity or the thermal conductivity.

  17. Hemograma, sódio, potássio, cálcio, osmolalidade e viscosidade durante angiocardiografia pediátrica com ioxaglato Blood cell count, sodium, potassium, calcium, osmolality and viscosity, during pediatric angiocardiography with ioxaglate

    Directory of Open Access Journals (Sweden)

    Mauro Regis Silva Moura

    1998-04-01

    Full Text Available OBJETIVO: Os meios de contraste (MC introduzem alterações em alguns parâmetros sangüíneos, adquirindo, assim, mais importância na angiocardiografia pediátrica. MÉTODOS: Estudamos a presença e a severidade das mudanças no hematócrito, hemoglobina, leucócitos, sódio, potássio, cálcio, osmolalidade e viscosidade, em 35 crianças submetidas a angiocardiografia com ioxaglato, identificando, também, as variáveis independentes responsáveis por essas alterações. As amostras sangüíneas foram colhidas no início do procedimento (S1, no fim (S2 e 2h após (S3. RESULTADOS: Hematócrito: S1= 47,3±6,9%; S2= 40,7±7,4% (pPURPOSE: Children's blood changes during angiocardiography may not be only due to the contrast media (CM. METHODS: We studied the presence and severity of changes in those parameters in 35 pediatric patients undergoing angiocardiography with ioxaglate aiming to identify independent variables responsible for those changes. Blood samples were taken at the beginning of the procedure (S1, at the end (S2 and two hours later (S3. RESULTS: Hematocrit: S1= 47.3±6.9%; S2= 40.7± 7.4% (p<0.001, (related to the CM volume r=0.37, p<0.05. Hemoglobin: S1= 15±2.1g%; S2= 13.2±2.4g% (p<0.001, and S3= 12.7±2.5g% (NS. White blood cell count: S1= 7940±3040 leukocytes/mm³; S2= 6950± 2700/mm³ (NS; S3= 10830±4690 leukocytes/mm³, (p<0.001. Procedure duration (r=0.38, p<0.05 and 5% glucose fluid given between S2 and S3 (r=0.49, p<0.05 were isolated. Sodium: S1= 134.5±0.4mEq/L; S2= 130.7±0.4mEq/L (p<0.001 (due to 5% glucose fluid injected, r=0.61, p<0.01. Potassium: S1= 4.22±0.45mEq/L, S2= 3.83±0.4mEq/L (p<0.001. Calcium: S1= 9.13± 1.03mg%; S2= 8.4±0.91mg/dL. (related to the CM, r=0.43, p<0.01. Osmolality: S1= 293.3±12.5mOsm/kg; S2= 300.6±13.3mOsm/kg (p<0.001. Viscosity: S1= 3.36±0.81; S2= 3.09±0.74 (p<0.01; S3= 3.87±0.89, p<0.001. There was an indirect linear regression with the CM. CONCLUSION: There were profound

  18. Blood

    Science.gov (United States)

    ... Also, blood is either Rh-positive or Rh-negative. So if you have type A blood, it's either A positive or A negative. Which type you are is important if you need a blood transfusion. And your Rh factor could be important ...

  19. Viscosity of Thorium Soaps

    Directory of Open Access Journals (Sweden)

    RAMAKANT SHARMA

    2013-06-01

    Full Text Available The density and viscosity results of thorium soaps in benzene methanol mixture have been explained satisfactorily in terms of the equations proposed by Einstein, Vand and Jones-Dole. The values of the CMC and molar volume of thorium soaps calculated from these equations are in close agreement.

  20. Viscosity in accretion discs

    Energy Technology Data Exchange (ETDEWEB)

    Katz, J.I.

    1980-01-01

    Both HerX-1 and SS433 may contain accretion disks slaved to a precessing companion star. If so, it is possible to bound the effective viscosity in these disks. The results, in terms of the disk parameter alpha, are lower bounds of 0.01 for HerX-1 and of 0.1 for SS433.

  1. Viscosity of colloidal suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, E.G.D. [Rockefeller Univ., New York, NY (United States); Schepper, I.M. de [Delft Univ. of Technology (Netherlands)

    1995-12-31

    Simple expressions are given for the effective Newtonian viscosity as a function of concentration as well as for the effective visco-elastic response as a function of concentration and imposed frequency, of monodisperse neutral colloidal suspensions over the entire fluid range. The basic physical mechanisms underlying these formulae are discussed. The agreement with existing experiments is very good.

  2. Viscosity model of high-viscosity dispersing system

    Institute of Scientific and Technical Information of China (English)

    魏先福; 王娜; 黄蓓青; 孙承博

    2008-01-01

    High-viscosity dispersing system is formed by dispersing the solid particles in the high-viscosity continuous medium.It is very easy to form the three-dimensional network structure for solid particles in the system and the rheology behavior becomes complicated.The apparent viscosity of this dispersing system always has the connection with the volume ratio and the shear rate.In order to discuss the rheology behavior and put up the viscosity model,the suspension of silicon dioxide and silicon oil were prepared.Through testing the viscosity,the solid concentration and the shear rate,the effects of the ratio and the shear rate on viscosity was analyzed,the model of the high-viscosity dispersing system was designed and the model with the printing ink were validated.The experiment results show that the model is applicable to the high-viscosity dispersing systems.

  3. Clinical efficacy of salvia miltiorrhiza injection in the treatment of severe acute pancreatitis and its effect on the blood viscosity%丹参注射液对重症急性胰腺炎患者的治疗作用及对血黏度的影响

    Institute of Scientific and Technical Information of China (English)

    王友帆; 罗良坚

    2013-01-01

    [目的]观察丹参注射液对重症急性胰腺炎(SAP)患者的治疗作用及对血黏度的影响.[方法]2009年1月~2012年6月本院收治70例SAP患者随机分为2组,各35例.对照组患者给予常规支持性治疗;观察组在常规支持性治疗的基础上同时应用丹参注射液,40ml/d,静脉滴注,10 d为一疗程.比较2组患者的临床症状消失时间,血和尿淀粉酶及白细胞计数恢复正常时间;治疗前及治疗10 d测定2组患者的血黏度.[结果]观察组患者临床症状消失时间,血淀粉酶、尿淀粉酶及白细胞复常时间均较对照组显著缩短(P<0.01);治疗后2组患者全血高切黏度、全血中切黏度、全血低切黏度和血浆黏度均较治疗前显著降低(P<0.01),且观察组上述血黏度指标均较对照组显著降低(P<0.01).[结论]丹参注射液辅助治疗SAP具有较好的疗效,其机制可能与降低血黏度而改善微循环有关.%[Objective]To explore the clinical efficacy of salvia miltiorrhiza injection in the treatment of severe acute pancreatitis,and to study its effect on the blood viscosity.[Methods]Seventy patients with severe acute pancreatitis,who visited our hospital in January 2009-June 2012,were randomly divided into Observation Group and Control Group.There were 35 cases in each group.Cases in Control Group received routine supportive treatment,and cases in Observation Group received routine supportive treatment plus salvia miltiorrhiza injection 40ml/d for 10 day.Time of clinical symptoms disappearing,blood amylase recovery,urine amylase recovery and leukocyte recovery was compared in both groups after treatment.Blood viscosity was determined in both groups before treatment and on 10th day after treatment.[Results] Time of clinical symptoms disappearing,blood amylase recovery,urine amylase recovery and leukocyte recovery in Observation Group was significantly shortened than Control Group (P<0.01).Low shear viscosity,medium shear

  4. Hall Viscosity I: Linear Response Theory for Viscosity

    Science.gov (United States)

    Bradlyn, Barry; Goldstein, Moshe; Read, Nicholas

    2012-02-01

    In two dimensional systems with broken time-reversal symmetry, there can exist a non-dissipative viscosity coefficient [1,2,3]. This Hall viscosity is similar in nature to the non-dissipative Hall conductivity. In order to investigate this phenomenon further, we develop a linear response formalism for viscosity. We derive a Kubo formula for the frequency dependent viscosity tensor in the long wavelength limit. We compute the viscosity tensor for the free electron gas, integer quantum Hall systems, and two-dimensional paired superfluids. In the zero frequency limit, we show how the known results [3,4] for the Hall viscosity are recovered.[4pt] [1] J. Avron, R. Seiler, and P. Zograf, Phys. Rev. Lett. 75, 697 (1995).[0pt] [2] P. Levay, J. Math. Phys. 36, 2792 (1995).[0pt] [3] N. Read, Phys. Rev. B 79, 045308 (2009).[0pt] [4] N. Read and E. Rezayi, Phys. Rev. B 84, 085316 (2011).

  5. Plasma viscosity increase with progression of peripheral arterial atherosclerotic disease.

    Science.gov (United States)

    Poredos, P; Zizek, B

    1996-03-01

    Increased blood and plasma viscosity has been described in patients with coronary and peripheral arterial disease. However, the relation of viscosity to the extent of arterial wall deterioration--the most important determinant of clinical manifestation and prognosis of the disease--is not well known. Therefore, the authors studied plasma viscosity as one of the major determinants of blood viscosity in patients with different stages of arterial disease of lower limbs (according to Fontaine) and its relation to the presence of some risk factors of atherosclerosis. The study encompassed four groups of subjects: 19 healthy volunteers (group A), 18 patients with intermittent claudication up to 200 m (stage II; group B), 15 patients with critical ischemia of lower limbs (stage III and IV; group C), and 16 patients with recanalization procedures on peripheral arteries. Venous blood samples were collected from an antecubital vein without stasis for the determination of plasma viscosity (with a rotational capillary microviscometer, PAAR), fibrinogen, total cholesterol, alpha-2-macroglobulin, and glucose concentrations. In patients with recanalization procedure local plasma viscosity was also determined from blood samples taken from a vein on the dorsum of the foot. Plasma viscosity was most significantly elevated in the patients with critical ischemia (1.78 mPa.sec) and was significantly higher than in the claudicants (1.68 mPa.sec), and the claudicants also had significantly higher viscosity than the controls (1.58 mPa.sec). In patients in whom a recanalization procedure was performed, no differences in systemic and local plasma viscosity were detected, neither before nor after recanalization of the diseased artery. In all groups plasma viscosity was correlated with fibrinogen concentration (r=0.70, P < 0.01) and total cholesterol concentration (r=0.24, P < 0.05), but in group C (critical ischemia) plasma viscosity was most closely linked to the concentration of alpha-2

  6. Effective Viscosity Coefficient of Nanosuspensions

    Science.gov (United States)

    Rudyak, V. Ya.; Belkin, A. A.; Egorov, V. V.

    2008-12-01

    Systematic calculations of the effective viscosity coefficient of nanosuspensions have been performed using the molecular dynamics method. It is established that the viscosity of a nanosuspension depends not only on the volume concentration of the nanoparticles but also on their mass and diameter. Differences from Einstein's relation are found even for nanosuspensions with a low particle concentration.

  7. Can bulk viscosity drive inflation

    Energy Technology Data Exchange (ETDEWEB)

    Pacher, T.; Stein-Schabes, J.A.; Turner, M.S.

    1987-09-15

    Contrary to other claims, we argue that bulk viscosity associated with the interactions of non- relativistic particles with relativistic particles around the time of the grand unified theory (GUT) phase transition cannot lead to inflation. Simply put, the key ingredient for inflation, negative pressure, cannot arise due to the bulk-viscosity effects of a weakly interacting mixture of relativistic and nonrelativistic particles.

  8. Volatiles Which Increase Magma Viscosity

    Science.gov (United States)

    Webb, S.

    2015-12-01

    The standard model of an erupting volcano is one in which the viscosity of a decompressing magma increases as the volatiles leave the melt structure to form bubbles. It has now been observed that the addition of the "volatiles" P, Cl and F result in an increase in silicate melt viscosity. This observation would mean that the viscosity of selected degassing magmas would decrease rather than increase. Here we look at P, Cl and F as three volatiles which increase viscosity through different structural mechanisms. In all three cases the volatiles increase the viscosity of peralkaline composition melts, but appear to always decrease the viscosity of peraluminous melts. Phosphorus causes the melt to unmix into a Na-P rich phase and a Na-poor silicate phase. Thus as the network modifying Na (or Ca) are removed to the phosphorus-rich melt, the matrix melt viscosity increases. With increasing amounts of added phosphorus (at network modifying Na ~ P) the addition of further phosphorus causes a decrease in viscosity. The addition of chlorine to Fe-free aluminosilicate melts results in an increase in viscosity. NMR data on these glass indicates that the chlorine sits in salt-like structures surrounded by Na and/or Ca. Such structures would remove network-modifying atoms from the melt structure and thus result in an increase in viscosity. The NMR spectra of fluorine-bearing glasses shows that F takes up at least 5 different structural positions in peralkaline composition melts. Three of these positions should result in a decrease in viscosity due to the removal of bridging oxygens. Two of the structural positons of F, however, should result in an increase in viscosity as they require the removal of network-modifying atoms from the melt structure (with one of the structures being that observed for Cl). This would imply that increasing amounts of F might result in an increase in viscosity. This proposed increase in viscosity with increasing F has now been experimentally confirmed.

  9. ZBLAN Viscosity Instrumentation

    Science.gov (United States)

    Kaukler, William

    2001-01-01

    The past year's contribution from Dr. Kaukler's experimental effort consists of these 5 parts: a) Construction and proof-of-concept testing of a novel shearing plate viscometer designed to produce small shear rates and operate at elevated temperatures; b) Preparing nonlinear polymeric materials to serve as standards of nonlinear Theological behavior; c) Measurements and evaluation of above materials for nonlinear rheometric behavior at room temperature using commercial spinning cone and plate viscometers available in the lab; d) Preparing specimens from various forms of pitch for quantitative comparative testing in a Dynamic Mechanical Analyzer, Thermal Mechanical Analyzer; and Archeological Analyzer; e) Arranging to have sets of pitch specimens tested using the various instruments listed above, from different manufacturers, to form a baseline of the viscosity variation with temperature using the different test modes offered by these instruments by compiling the data collected from the various test results. Our focus in this project is the shear thinning behavior of ZBLAN glass over a wide range of temperature. Experimentally, there are no standard techniques to perform such measurements on glasses, particularly at elevated temperatures. Literature reviews to date have shown that shear thinning in certain glasses appears to occur, but no data is available for ZBLAN glass. The best techniques to find shear thinning behavior require the application of very low rates of shear. In addition, because the onset of the thinning behavior occurs at an unknown elevated temperature, the instruments used in this study must provide controlled low rates of shear and do so for temperatures approaching 600 C. In this regard, a novel shearing parallel plate viscometer was designed and a prototype built and tested.

  10. Impact of dual antiplatelet therapy on blood viscosity after treatment with drug-eluting coronary stents%双联抗血小板治疗对药物洗脱支架术后患者血液流变学的影响

    Institute of Scientific and Technical Information of China (English)

    阚静; 陈绍良; 林玲; 徐海梅; 赵莹莹; 刘彦; 陈峰

    2013-01-01

    目的 探讨双联抗血小板治疗对药物洗脱支架术后不同性别患者血液流变学的影响.方法 选择2009年9月至2009年12月接受药物洗脱支架置入术的598例冠心病患者,排除急性心肌梗死、急性脑梗死、肿瘤、肺源性心脏病、血流变学检查异常者,共有444例患者纳入分析.其中214例在术后9个月完成血液流变学检测随访.用ZL9000 PLUS型血流变测定仪测定全血黏度(高切、中切、低切)、血浆黏度、血细胞比容、红细胞变形指数、红细胞聚集指数、红细胞电泳时间.结果 药物洗脱支架术后双联抗血小板治疗9个月时,患者的全血黏度均明显升高,但全血低切还原黏度轻度降低,男性组红细胞沉降率和红细胞沉降率方程K值(除去血细胞比容的影响后的红细胞沉降率校正值)明显减小,但女性组变化不明显.结论 双联抗血小板治疗可以降低男性红细胞聚集,从而减少男性冠心病患者药物洗脱支架术后主要不良心脏事件的发生.%Objective To study the effect of dual antiplatelet therapy on blood viscosity in women and men after drug-eluting stent implantation. Methods 598 consecutive patients with coronary artery disease were treated by drug-eluting stent implantation from May 2009 to December 2010,of which 444 patients were included in the analysis,excluded acute myocardial infarction,acute cerebral infarction,tumor,cor pulmonale,and abnormal hemorrheology. 214 among them completed with hemorrheology follow-up 9 months after the teatment. The hemorheology was measured with hemorrheology tester (ZL9000 PLUS),including whole blood viscosity (high cut,cut,low cut),plasma viscosity,red blood cell deposited,erythrocyte deformation index,red cell aggregation index, and red blood cells electrophoretic time. Results Whole blood viscosity were significantly increased in patients with dual antiplatelet therapy continue 9-months after drug-eluting stent implantation

  11. 不同治法方药对激素性股骨头坏死鸡血脂、血黏度、凝血及纤溶功能的影响%Effects of different therapeutic methods and prescriptions on blood fat, blood viscosity, blood coagulation and fibrinolysis of chickens with steroid-induced necrosis of femoral head

    Institute of Scientific and Technical Information of China (English)

    王荣田; 林诗富; 万蓉; 殷小杰; 王智耀; 刘道兵; 林娜; 陈卫衡

    2013-01-01

    Objective: To compare the effects between STRENGTHENING SPLEEN RESOLV PHLEGM combined with ACTIVAT BLOOD DREDGING COLLATERALS and REINFORCING KIDNEY SUPPERS BONE combined with ACTIVAT BLOOD DREDGING COLLATERALS on blood fat, blood viscosity, blood coagulation and fibrinolysis of chickens with steroid-induced necrosis of femoral head (SNFH) ,and to explore the mechanism of action and the role of the two methods in the prevention of SNFH. Methods: Eighty leghorn chickens were randomly divided into normal group,model group,lovastatin group,STRENGTHENING SPLEEN(SS)group and REINFORCING KIDNEY( RK) group. Chickens were administrated with pectoral intramuscular injection of methylprednisolone sodium succinate except those in the normal group, and chickens in lovastatin group, SS group and RK group were simultaneously administrated with respective medicine. After 8 and 16 weeks of medication, venous blood was respectively collected from the chickens in batches for detecting the following parameters as whole blood viscosity (ηb ) , plasma viscosity (ηp ) , hematocrit( HCT) , fibrinogen ( FIB ) ,high density lipoprotein ( HDL ) ,low density lipoprotein ( LDL) , cholesterol total ( CHOL) , triglyceride ( TG) , plasma plasminogen ( PLG) , antithrombin M (AT- M ) , tissue-type plasminogen activator( t-PA) ,activated partial thromboplastin time( APTT) , thrombin time (TT) and prothrombin time(PT). After blood collection,the chickens were executed for fetching out their bilateral femoral heads, which were sectioned for histological observation. Results: 1) The results of histological observation under a light microscope: In normal group cartilage cells lined up in order; bone trabeculae were in regular, close and well-stacked arrangement, surrounded by some osteoblasts and a small number of osteoclasts; and no hypertrophic fat cells were found. The following situations were found in model group as tufted hypertrophic cartilage cells arranged irregularly, thin bone trabeculae

  12. Fission hindrance and nuclear viscosity

    Indian Academy of Sciences (India)

    Indranil Mazumdar

    2015-08-01

    We discuss the role of nuclear viscosity in hindering the fission of heavy nuclei as observed in the experimental measurements of GDR -ray spectra from the fissioning nuclei. We review a set of experiments carried out and reported by us previously [see Dioszegi et al, Phys. Rev. C 61, 024613 (2000); Shaw et al, Phys. Rev. C 61, 044612 (2000)] and argue that the nuclear viscosity parameter has no apparent dependence on temperature. However, it may depend upon the deformation of the nucleus.

  13. Viscosities of the quasigluon plasma

    CERN Document Server

    Bluhm, M; Redlich, K

    2010-01-01

    We investigate bulk and shear viscosities of the gluon plasma within relaxation time approximation to an effective Boltzmann-Vlasov type kinetic theory by viewing the plasma as describable in terms of quasigluon excitations with temperature dependent self-energies. The found temperature dependence of the transport coefficients agrees fairly well with available lattice QCD results. The impact of some details in the quasigluon dispersion relation on the specific shear viscosity is discussed.

  14. Can bulk viscosity drive inflation

    Energy Technology Data Exchange (ETDEWEB)

    Pacher, T.; Stein-Schabes, J.A.; Turner, M.S.

    1987-04-01

    Contrary to other claims, we argue that, bulk viscosity associated with the interactions of nonrelativistic particles with relativistic particles around the time of the grand unified theory (GUT) phase transition cannot lead to inflation. Simply put, the key ingredient for inflation, negative pressure, cannot arise due to the bulk viscosity effects of a weakly-interacting mixture of relativistic and nonrelativistic particles. 13 refs., 1 fig.

  15. Viscosity model for aluminosilicate melt

    Directory of Open Access Journals (Sweden)

    Zhang G.H.

    2012-01-01

    Full Text Available The structurally based viscosity model proposed in our previous study is extended to include more components, e.g. SiO2, Al2O3, FeO, MnO, MgO, CaO, Na2O and K2O. A simple method is proposed to calculate the numbers of different types of oxygen ions classified by the different cations they bonded with, which is used to characterize the influence of composition on viscosity. When dealing with the aluminosilicate melts containing several basic oxides, the priority order is established for different cations for charge compensating Al3+ ions, according to the coulombic force between cation and oxygen anion. It is indicated that basic oxides have two paradox influences on viscosity: basic oxide with a higher basicity decreases viscosity more greatly by forming weaker non-bridging oxygen bond; while it increases viscosity more greatly by forming stronger bridging oxygen bond in tetrahedron after charge compensating Al3+ ion. The present model can extrapolate its application range to the system without SiO2. Furthermore, it could also give a satisfy interpretation to the abnormal phenomenon that viscosity increases when adding K2O to CaO-Al2O3-SiO2 melt within a certain composition range.

  16. Effects of different anesthetics on levels of plasma cytokines and blood viscosity in perioperative esophageal cancer patients%不同麻醉药物对围术期食管癌根治术患者血清中细胞因子水平及血液流变学的影响及临床意义

    Institute of Scientific and Technical Information of China (English)

    房成; 郭新玲; 刘和平; 滕清雷; 苏蔚

    2012-01-01

    Objective To study the perioperative changes of serum concentration of IL-6, IL-10 and the blood viscosity selected in perioperative esophageal cancer patients with Propofol, Enflurane and Isoflurane. Methods 45 ASA II , III patients scheduled for esophagus cancer surgery were randomly allocated to one of the three groups: Propofol group (group A), Enflurane group (group B) and Isoflurane (group C). 3 groups were observed the HR, SBP, DBP, MAP changes at before induction (To), 1 h after thomcotomy (T1), and 24 h after operation (T1). Blood samples were taken from internal jugular vein at To, 1, and T2 for determination of serum IL-6, IL-10 and plasma viscosity. Results The HR, SBP, DBP, MAP of the 3 groups were not significantlyfly different at all observation points (P > 0.05). All patients showed significant increases in IL-6 and IL-10 levels during T1 and T2. The concentration of IL-6 and blood viscosity in group A was lower than those of group B and C during T1 and T2 (P < 0.05). The concentration of IL-10 in group A was higher than that of group B and C (P < 0.05). Conclusion Propofol can modulate the production of IL-6, IL-10 and blood viscosity, can acts as a better anesthetic.%目的 探讨丙泊酚、安氟醚、异氟醚对围术期食管癌根治术患者血清中细胞因子白介素6(IL-6)和白介素10(IL-10)水平的影响以及患者血液流变学参数的变化特点,为临床麻醉合理用药提供理论依据.方法 择期行食管癌手术患者45例(ASAⅠ、Ⅱ级),随机分为三组:丙泊酚组(A组),安氟醚组(B组),异氟醚(C组),每组15例,分别于诱导前(T0)、进胸后1 h(T1)及手术结束后24 h(T2),记录心率(heart rate,HR)、收缩压(systolic blood pressure,SBP)、舒张压(diastolic blood pressure,DBP)、平均动脉压(mean arterial pressure,MAP),抽取外周静脉血,酶联免疫吸附法(ELASA法)检测血清中细胞因子IL-6、IL-10浓度,全自动血黏度仪检测低切变率下全血黏度.结果 各组在不

  17. Review on Nanofluid Theoretical Viscosity Models

    Directory of Open Access Journals (Sweden)

    P. C. Mukesh Kumar

    2012-04-01

    Full Text Available Much interest is shown on nanofluid as nanofluid is suitable for cooling applications. The two important thermo physical properties of nanofluid such as thermal conductivity and viscosity play key role in practical heat transfer situations. The nanofluid viscosity is investigated by many investigators next to the thermal conductivity of nanofluid as the viscosity determines the pumping power. This review summarizes the nanofluids theoretical viscosity models proposed by different research groups. Though many viscosity models formulated of nanofluids, there is no universally accepted model and reliable mechanism for viscosity over the particles volume fraction. Therefore this review leads to further investigation on the hotly debated topic of viscosity of nanofluids.

  18. Viscosity kernel of molecular fluids

    DEFF Research Database (Denmark)

    Puscasu, Ruslan; Todd, Billy; Daivis, Peter

    2010-01-01

    , temperature, and chain length dependencies of the reciprocal and real-space viscosity kernels are presented. We find that the density has a major effect on the shape of the kernel. The temperature range and chain lengths considered here have by contrast less impact on the overall normalized shape. Functional...... forms that fit the wave-vector-dependent kernel data over a large density and wave-vector range have also been tested. Finally, a structural normalization of the kernels in physical space is considered. Overall, the real-space viscosity kernel has a width of roughly 3–6 atomic diameters, which means...

  19. The viscosity of dimethyl ether

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Jakobsen, Jørgen

    2007-01-01

    and NOx traps are installed. The most significant problem encountered when engines are fuelled with DME is that the injection equipment breaks down prematurely due to extensive wear. This tribology issue can be explained by the very low lubricity and viscosity of DME. Recently, laboratory methods have...... appeared capable of measuring these properties of DME. The development of this is rendered difficult because DME has to be pressurised to remain in the liquid state and it dissolves most of the commercially available elastomers. This paper deals fundamentally with the measurement of the viscosity of DME...

  20. Pressure Effect on Extensional Viscosity

    DEFF Research Database (Denmark)

    Christensen, Jens Horslund; Kjær, Erik Michael

    1999-01-01

    The primary object of these experiments was to investigate the influence of hydrostatic pressure on entrance flow. The effect of pressure on shear and extensional viscosity was evaluated using an axis symmetric capillary and a slit die where the hydrostatic pressure was raised with valves...

  1. Effective viscosity of confined hydrocarbons

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Samoilov, V.N.; Persson, B.N.J.

    2012-01-01

    We present molecular dynamics friction calculations for confined hydrocarbon films with molecular lengths from 20 to 1400 carbon atoms. We find that the logarithm of the effective viscosity ηeff for nanometer-thin films depends linearly on the logarithm of the shear rate: log ηeff=C-nlog γ̇, where...

  2. The Universe With Bulk Viscosity

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Exact solutions for a model with variable G, A and bulk viscosity areobtained. Inflationary solutions with constant (de Sitter-type) and variable energydensity are found. An expanding anisotropic universe is found to isotropize duringits expansion but a static universe cannot isotropize. The gravitational constant isfound to increase with time and the cosmological constant decreases with time asAo∝t-2.

  3. Fluid viscosity under confined conditions

    Science.gov (United States)

    Rudyak, V. Ya.; Belkin, A. A.

    2014-12-01

    Closed equations of fluid transfer in confined conditions are constructed in this study using ab initio methods of nonequilibrium statistical mechanics. It is shown that the fluid viscosity is not determined by the fluid properties alone, but becomes a property of the "fluid-nanochannel walls" system as a whole. Relations for the tensor of stresses and the interphase force, which specifies the exchange by momentum of fluid molecules with the channel-wall molecules, are derived. It is shown that the coefficient of viscosity is now determined by the sum of three contributions. The first contribution coincides with the expression for the coefficient of the viscosity of fluid in the bulk being specified by the interaction of fluid molecules with each other. The second contribution has the same structure as the first one but is determined by the interaction of fluid molecules with the channel-wall molecules. Finally, the third contribution has no analog in the usual statistical mechanics of transport processes of a simple fluid. It is associated with the correlation of intermolecular forces of the fluid and the channel walls. Thus, it is established that the coefficient of viscosity of fluid in sufficiently small channels will substantially differ from its bulk value.

  4. Influence of electromagnetic radiation produced by mobile phone on some biophysical blood properties in rats.

    Science.gov (United States)

    El-Bediwi, Abu Bakr; Saad, Mohamed; El-kott, Attall F; Eid, Eman

    2013-04-01

    Effects of electromagnetic radiation produced by mobile phone on blood viscosity, plasma viscosity, hemolysis, Osmotic fragility, and blood components of rats have been investigated. Experimental results show that there are significant change on blood components and its viscosity which affects on a blood circulation due to many body problems. Red blood cells, White blood cells, and Platelets are broken after exposure to electromagnetic radiation produced by mobile phone. Also blood viscosity and plasma viscosity values are increased but Osmotic fragility value decreased after exposure to electromagnetic radiation produced by mobile phone.

  5. On the Viscosity of Emulsions

    CERN Document Server

    Kroy, K; Djabourov, M; Kroy, Klaus; Capron, Isabelle; Djabourov, Madeleine

    1999-01-01

    Combining direct computations with invariance arguments, Taylor's constitutive equation for an emulsion can be extrapolated to high shear rates. We show that the resulting expression is consistent with the rigorous limits of small drop deformation and that it bears a strong similarity to an a priori unrelated rheological quantity, namely the dynamic (frequency dependent) linear shear response. More precisely, within a large parameter region the nonlinear steady-state shear viscosity is obtained from the real part of the complex dynamic viscosity, while the first normal stress difference is obtained from its imaginary part. Our experiments with a droplet phase of a binary polymer solution (alginate/caseinate) can be interpreted by an emulsion analogy. They indicate that the predicted similarity rule generalizes to the case of moderately viscoelastic constituents that obey the Cox-Merz rule.

  6. Viscosity of Earth's Outer Core

    CERN Document Server

    Smylie, D E

    2007-01-01

    A viscosity profile across the entire fluid outer core is found by interpolating between measured boundary values, using a differential form of the Arrhenius law governing pressure and temperature dependence. The discovery that both the retrograde and prograde free core nutations are in free decay (Palmer and Smylie, 2005) allows direct measures of viscosity at the top of the outer core, while the reduction in the rotational splitting of the two equatorial translational modes of the inner core allows it to be measured at the bottom. We find 2,371 plus/minus 1,530 Pa.s at the top and 1.247 plus/minus 0.035 x 10^11 Pa.s at the bottom. Following Brazhkin (1998) and Brazhkin and Lyapin (2000) who get 10^2 Pa.s at the top, 10^11 Pa.s at the bottom, by an Arrhenius extrapolation of laboratory experiments, we use a differential form of the Arrhenius law to interpolate along the melting temperature curve to find a viscosity profile across the outer core. We find the variation to be closely log-linear between the meas...

  7. Viscosity Index Improvers and Thickeners

    Science.gov (United States)

    Stambaugh, R. L.; Kinker, B. G.

    The viscosity index of an oil or an oil formulation is an important physical parameter. Viscosity index improvers, VIIs, are comprised of five main classes of polymers: polymethylmethacrylates (PMAs), olefin copolymers (OCPs), hydrogenated poly(styrene-co-butadiene or isoprene) (HSD/SIP/HRIs), esterified polystyrene-co-maleic anhydride (SPEs) and a combination of PMA/OCP systems. The chemistry, manufacture, dispersancy and utility of each class are described. The comparative functions, properties, thickening ability, dispersancy and degradation of VIIs are discussed. Permanent and temporary shear thinning of VII-thickened formulations are described and compared. The end-use performance and choice of VI improvers is discussed in terms of low- and high-temperature viscosities, journal bearing oil film thickness, fuel economy, oil consumption, high-temperature pumping efficiency and deposit control. Discussion of future developments concludes that VI improvers will evolve to meet new challenges of increased thermal-oxidative degradation from increased engine operating temperatures, different base stocks of either synthetic base oils or vegetable oil-based, together with alcohol- or vegetable oil-based fuels. VI improvers must also evolve to deal with higher levels of fuel dilution and new types of sludge and also enhanced low-temperature requirements.

  8. Shear viscosity of nuclear matter

    CERN Document Server

    Magner, A G; Grygoriev, U V; Plujko, V A

    2016-01-01

    Shear viscosity $\\eta$ is calculated for the nuclear matter described as a system of interacting nucleons with the van der Waals (VDW) equation of state. The Boltzmann-Vlasov kinetic equation is solved in terms of the plane waves of the collective overdamped motion. In the frequent collision regime, the shear viscosity depends on the particle number density $n$ through the mean-field parameter $a$ which describes attractive forces in the VDW equation. In the temperature region $T=15\\div 40$~MeV, a ratio of the shear viscosity to the entropy density $s$ is smaller than 1 at the nucleon number density $n =(0.5\\div 1.5)\\,n^{}_0$, where $n^{}_0=0.16\\,$fm$^{-3}$ is the particle density of equilibrium nuclear matter at zero temperature. A minimum of the $\\eta/s$ ratio takes place somewhere in a vicinity of the critical point of the VDW system. Large values of $\\eta/s\\gg 1$ are however found in both the low density, $n\\ll n^{}_0$, and high density, $n>2n^{}_0$, regions. This makes the ideal hydrodynamic approach ina...

  9. Extension of Radiative Viscosity to Superfluid Matter

    Institute of Scientific and Technical Information of China (English)

    PI Chun-Mei; YANG Shu-Hua; ZHENG Xiao-Ping

    2011-01-01

    The radiative viscosity of superfluid npe matter is studied and it is found that to the lowest order of δμ/T,the ratio of radiative viscosity to bulk viscosity is the same as that of its normal matter.As one of the most important transport coefficients,the bulk viscosities of simple npe matter,of hyperon matter and even of quark matter,both in normal and superfluid states,have been extensively studied,[1-18] for more detail see Ref.[19].%The radiative viscosity of superfluid npe matter is studied and it is found that to the lowest order of δμ/T, the ratio of radiative viscosity to bulk viscosity is the same as that of its normal matter.

  10. Viscosity of a nucleonic fluid

    CERN Document Server

    Mekjian, Aram Z

    2012-01-01

    The viscosity of nucleonic matter is studied both classically and in a quantum mechanical description. The collisions between particles are modeled as hard sphere scattering as a baseline for comparison and as scattering from an attractive square well potential. Properties associated with the unitary limit are developed which are shown to be approximately realized for a system of neutrons. The issue of near perfect fluid behavior of neutron matter is remarked on. Using some results from hard sphere molecular dynamics studies near perfect fluid behavior is discussed further.

  11. Drop Spreading with Random Viscosity

    Science.gov (United States)

    Xu, Feng; Jensen, Oliver

    2016-11-01

    Airway mucus acts as a barrier to protect the lung. However as a biological material, its physical properties are known imperfectly and can be spatially heterogeneous. In this study we assess the impact of these uncertainties on the rate of spreading of a drop (representing an inhaled aerosol) over a mucus film. We model the film as Newtonian, having a viscosity that depends linearly on the concentration of a passive solute (a crude proxy for mucin proteins). Given an initial random solute (and hence viscosity) distribution, described as a Gaussian random field with a given correlation structure, we seek to quantify the uncertainties in outcomes as the drop spreads. Using lubrication theory, we describe the spreading of the drop in terms of a system of coupled nonlinear PDEs governing the evolution of film height and the vertically-averaged solute concentration. We perform Monte Carlo simulations to predict the variability in the drop centre location and width (1D) or area (2D). We show how simulation results are well described (at much lower computational cost) by a low-order model using a weak disorder expansion. Our results show for example how variability in the drop location is a non-monotonic function of the solute correlation length increases. Engineering and Physical Sciences Research Council.

  12. Viscosity of ring polymer melts

    KAUST Repository

    Pasquino, Rossana

    2013-10-15

    We have measured the linear rheology of critically purified ring polyisoprenes, polystyrenes, and polyethyleneoxides of different molar masses. The ratio of the zero-shear viscosities of linear polymer melts η0,linear to their ring counterparts η0,ring at isofrictional conditions is discussed as a function of the number of entanglements Z. In the unentangled regime η0,linear/η 0,ring is virtually constant, consistent with the earlier data, atomistic simulations, and the theoretical expectation η0,linear/ η0,ring = 2. In the entanglement regime, the Z-dependence of ring viscosity is much weaker than that of linear polymers, in qualitative agreement with predictions from scaling theory and simulations. The power-law extracted from the available experimental data in the rather limited range 1 < Z < 20, η0,linear/η0,ring ∼ Z 1.2±0.3, is weaker than the scaling prediction (η0,linear/η0,ring ∼ Z 1.6±0.3) and the simulations (η0,linear/ η0,ring ∼ Z2.0±0.3). Nevertheless, the present collection of state-of-the-art experimental data unambiguously demonstrates that rings exhibit a universal trend clearly departing from that of their linear counterparts, and hence it represents a major step toward resolving a 30-year-old problem. © 2013 American Chemical Society.

  13. 乌龙丹对多梗死性痴呆模型大鼠血液黏度、内皮素及一氧化氮的影响%Effect of wu long dan on blood viscosity,endothelin and nitric oxide in rat model of multi-infarct dementia

    Institute of Scientific and Technical Information of China (English)

    彭康; 臧坤堂

    2005-01-01

    BACKGROUND: Wu long dan is the experienced formula summarized in the long-term clinical practice on the treatment ischemic cerebral vascular disorder and aims at "benefiting qi,strengthening spleen,tonifying kidney,activating blood circulation,promoting circulation of collaterals and resolving phlegm". It is indicated in the previous researches that such formula acts on improving microcirculation of cerebrum,regulating neural endocrinal system and being against cerebral ischemic injury. The increased blood viscosity and disturbance endothelin and nitric oxide(NO) secreted from vessels and nerve cells have participated in the pathological progression of multi-infarct dementia(MID) and affect mutually.OBJECTIVE: To probe into the effect of wu long dan on blood viscosity,NO and endothelin in MID model in rats by duplicating MID rat model.DESIGN: A randomized controlled and experimental study based on the experimental animals.SETTING: Department of traditional Chinese medicine in a military medical university of Chinese PLA.MATERIALS: The experiment was performed in Laboratory of Department of Traditional Chinese Medicine in First Military Medical University of Chinese PLA and Laboratory of Department of Neurological Internal Medicine in affiliated Zhujiang Hospital from January to August 2002. SD male rats of clean grade were employed,weighted(270 ± 30) g (Qualified No. 2000337). In the experiment,there were blank control,model group,wu long dan low dosage group and wu long dan high dosage group.METHODS: After internal carotid artery isolated,dried blood suspension of homologous rats was injected at the ratio of 1:200 to prepare MID rat model. Cone-plate stationary method was adopted for the determination of blood viscosity,radioimmunoassay was for the determination of endothelin and cadmium-reduction-colorimetric method was for NO determination. Water-alcohol sedimentation was for the preparation of wu long dan.MAIN OUTCOME MEASURES: Primary indexes: whole blood

  14. Bulk viscosity-driven suppression of shear viscosity effects on the flow harmonics at RHIC

    CERN Document Server

    Noronha-Hostler, J; Grassi, F

    2014-01-01

    The interplay between shear and bulk viscosities on the flow harmonics, $v_n$'s, at RHIC is investigated using the newly developed relativistic 2+1 hydrodynamical code v-USPhydro that includes bulk and shear viscosity effects both in the hydrodynamic evolution and also at freeze-out. While shear viscosity is known to attenuate the flow harmonics, we find that the inclusion of bulk viscosity decreases the shear viscosity-induced suppression of the flow harmonics bringing them closer to their values in ideal hydrodynamical calculations. Depending on the value of the bulk viscosity to entropy density ratio, $\\zeta/s$, in the quark-gluon plasma, the bulk viscosity-driven suppression of shear viscosity effects on the flow harmonics may require a re-evaluation of the previous estimates of the shear viscosity to entropy density ratio, $\\eta/s$, of the quark-gluon plasma previously extracted by comparing hydrodynamic calculations to heavy ion data.

  15. The performance of bioinspired valveless piezoelectric micropump with respect to viscosity change.

    Science.gov (United States)

    Lee, Seung Chul; Hur, Sunghoon; Kang, Dooho; Kim, Bo Heum; Lee, Sang Joon

    2016-04-29

    This study investigated the effect of the serial connection of two pumping chambers on transport of liquid with increased viscosity. A serially connected valveless piezoelectric micropump was fabricated inspired by the liquid-feeding strategy of a female mosquito drinking liquid with a wide range of viscosities, from nectar to blood. The performance of the micropump was investigated by varying the viscosity of working liquid. Results showed that the optimal phase difference between the two chambers was 180° out-of-phase for all viscosity conditions. The two chambers operating at 180° out-of-phase exhibited higher pumping performance compared with the sum of each single chamber solely actuated, when viscosity increased. The flow patterns in the micropump showed that the rectification efficiency improved with the increase in viscosity. Results indicated that the serially connected valveless piezoelectric micropump is more robust to the increase of viscosity than a single-chamber piezoelectric micropump. This study would be helpful in the design of microfluidic devices for transporting liquids with a wide range of viscosities.

  16. VISCOSITY DICTATES METABOLIC ACTIVITY of Vibrio ruber

    Directory of Open Access Journals (Sweden)

    Maja eBoric

    2012-07-01

    Full Text Available Little is known about metabolic activity of bacteria, when viscosity of their environment changes. In this work, bacterial metabolic activity in media with viscosity ranging from 0.8 to 29.4 mPas was studied. Viscosities up to 2.4 mPas did not affect metabolic activity of Vibrio ruber. On the other hand, at 29.4 mPas respiration rate and total dehydrogenase activity increased 8 and 4-fold, respectively. The activity of glucose-6-phosphate dehydrogenase increased up to 13-fold at higher viscosities. However, intensified metabolic activity did not result in faster growth rate. Increased viscosity delayed the onset as well as the duration of biosynthesis of prodigiosin. As an adaptation to viscous environment V. ruber increased metabolic flux through the pentose phosphate pathway and reduced synthesis of a secondary metabolite. In addition, V. ruber was able to modify the viscosity of its environment.

  17. Viscosity in Modified Gravity 

    Directory of Open Access Journals (Sweden)

    Iver Brevik

    2012-11-01

    Full Text Available A bulk viscosity is introduced in the formalism of modified gravity. It is shownthat, based on a natural scaling law for the viscosity, a simple solution can be found forquantities such as the Hubble parameter and the energy density. These solutions mayincorporate a viscosity-induced Big Rip singularity. By introducing a phase transition inthe cosmic fluid, the future singularity can nevertheless in principle be avoided. 

  18. Shear Viscosity from Lattice QCD

    CERN Document Server

    Mages, Simon W; Fodor, Zoltán; Schäfer, Andreas; Szabó, Kálmán

    2015-01-01

    Understanding of the transport properties of the the quark-gluon plasma is becoming increasingly important to describe current measurements at heavy ion collisions. This work reports on recent efforts to determine the shear viscosity h in the deconfined phase from lattice QCD. The main focus is on the integration of the Wilson flow in the analysis to get a better handle on the infrared behaviour of the spectral function which is relevant for transport. It is carried out at finite Wilson flow time, which eliminates the dependence on the lattice spacing. Eventually, a new continuum limit has to be carried out which sends the new regulator introduced by finite flow time to zero. Also the non-perturbative renormalization strategy applied for the energy momentum tensor is discussed. At the end some quenched results for temperatures up to 4 : 5 T c are presented

  19. Drop spreading with random viscosity

    CERN Document Server

    Xu, Feng

    2016-01-01

    We examine theoretically the spreading of a viscous liquid drop over a thin film of uniform thickness, assuming the liquid's viscosity is regulated by the concentration of a solute that is carried passively by the spreading flow. The solute is assumed to be initially heterogeneous, having a spatial distribution with prescribed statistical features. To examine how this variability influences the drop's motion, we investigate spreading in a planar geometry using lubrication theory, combining numerical simulations with asymptotic analysis. We assume diffusion is sufficient to suppress solute concentration gradients across but not along the film. The solute field beneath the bulk of the drop is stretched by the spreading flow, such that the initial solute concentration immediately behind the drop's effective contact lines has a long-lived influence on the spreading rate. Over long periods, solute swept up from the precursor film accumulates in a short region behind the contact line, allowing patches of elevated v...

  20. Bacterial accumulation in viscosity gradients

    Science.gov (United States)

    Waisbord, Nicolas; Guasto, Jeffrey

    2016-11-01

    Cell motility is greatly modified by fluid rheology. In particular, the physical environments in which cells function, are often characterized by gradients of viscous biopolymers, such as mucus and extracellular matrix, which impact processes ranging from reproduction to digestion to biofilm formation. To understand how spatial heterogeneity of fluid rheology affects the motility and transport of swimming cells, we use hydrogel microfluidic devices to generate viscosity gradients in a simple, polymeric, Newtonian fluid. Using video microscopy, we characterize the random walk motility patterns of model bacteria (Bacillus subtilis), showing that both wild-type ('run-and-tumble') cells and smooth-swimming mutants accumulate in the viscous region of the fluid. Through statistical analysis of individual cell trajectories and body kinematics in both homogeneous and heterogeneous viscous environments, we discriminate passive, physical effects from active sensing processes to explain the observed cell accumulation at the ensemble level.

  1. The effects of viscosity on circumplanetary disks

    Institute of Scientific and Technical Information of China (English)

    De-Fu Bu; Hsien Shang; Feng Yuan

    2013-01-01

    The effects of viscosity on the circumplanetary disks residing in the vicinity of protoplanets are investigated through two-dimensional hydrodynamical simulations with the shearing sheet model.We find that viscosity can considerably affect properties of the circumplanetary disk when the mass of the protoplanet Mp (<) 33 M(⊙),where M(⊙) is the Earth's mass.However,effects of viscosity on the circumplanetary disk are negligibly small when the mass of the protoplanet Mp(>) 33 M(⊙).We find that when Mp(<) 33 M(⊙),viscosity can markedly disrupt the spiral structure of the gas around the planet and smoothly distribute the gas,which weakens the torques exerted on the protoplanet.Thus,viscosity can slow the migration speed of a protoplanet.After including viscosity,the size of the circumplanetary disk can be decreased by a factor of (>) 20%.Viscosity helps to transport gas into the circumplanetary disk from the differentially rotating circumstellar disk.The mass of the circumplanetary disk can be increased by a factor of 50% after viscosity is taken into account when Mp(<) 33 M(⊙).Effects of viscosity on the formation of planets and satellites are briefly discussed.

  2. Surface dilatational viscosity of Langmuir monolayers

    Science.gov (United States)

    Lopez, Juan; Vogel, Michael; Hirsa, Amir

    2003-11-01

    With increased interest in microfluidic systems, interfacial phenomena is receiving more attention. As the length scales of fluid problems decrease, the surface to volume ratio increases and the coupling between interfacial flow and bulk flow becomes increasingly dominated by effects due to intrinsic surface viscosities (shear and dilatational), in comparison to elastic effects (due to surface tension gradients). The surface shear viscosity is well-characterized, as cm-scale laboratory experiments are able to isolate its effects from other interfacial processes (e.g., in the deep-channel viscometer). The same is not true for the dilatational viscosity, because it acts in the direction of surface tension gradients. Their relative strength scale with the capillary number, and for cm-scale laboratory flows, surface tension effects tend to dominate. In microfluidic scale flows, the scaling favors viscosity. We have devised an experimental apparatus which is capable of isolating and enhancing the effects of dilatational viscosity at the cm scales by driving the interface harmonically in time, while keeping the interface flat. In this talk, we shall present both the theory for how this works as well as experimental measurements of surface velocity from which we deduce the dilatational viscosity of several monolayers on the air-water interface over a substantial range of surface concentrations. Anomalous behavior over some range of concentration, which superficially indicates negative viscosity, maybe explained in terms of compositional effects due to large spatial and temporal variations in concentration and corresponding viscosity.

  3. The Friction Theory for Viscosity Modeling

    DEFF Research Database (Denmark)

    Cisneros, Sergio; Zeberg-Mikkelsen, Claus Kjær; Stenby, Erling Halfdan

    2001-01-01

    In this work the one-parameter friction theory (f-theory) general models have been extended to the viscosity prediction and modeling of characterized oils. It is demonstrated that these simple models, which take advantage of the repulsive and attractive pressure terms of cubic equations of state...... such as the SRK, PR and PRSV, can provide accurate viscosity prediction and modeling of characterized oils. In the case of light reservoir oils, whose properties are close to those of normal alkanes, the one-parameter f-theory general models can predict the viscosity of these fluids with good accuracy. Yet......, in the case when experimental information is available a more accurate modeling can be obtained by means of a simple tuning procedure. A tuned f-theory general model can deliver highly accurate viscosity modeling above the saturation pressure and good prediction of the liquid-phase viscosity at pressures...

  4. A Study of the Effects of Carbon Disulfide Exposure on the Blood Lipids and Serum Trace Elements in Viscose Rayon Workers%二硫化碳接触工人血脂和血清微量元素的变化

    Institute of Scientific and Technical Information of China (English)

    孔丹莉; 毕勇毅; 等

    2001-01-01

    [Objective] To explore the level and the effects of carbon disulfide exposure on the blood lipids and serum trace elements in viscose rayon workers. [Methods] The epidemiological cross-sectional investigation and lab examination were carried out. [Results] HDL-C in the exposed group was lower than that in the intervention and control groups,however ApoB in the exposed group was higher than that in the intervention and control groups. The serum copper,zinc and selenium concentrations in the intervention group and the exposed group were lower than those in the control group. [Conclusion] The results indicated that those indexes might be taken as sensitive biomarkers for health surveillance of cardiovascular system.%[目的]探讨二硫化碳(CS2)作业工人血脂及血清微量元素含量的改变。[方法]运用流行病学横断面调查和实验室检查。[结果]接触组高密度脂蛋白(HDL-C)较干预组和对照组低,载脂蛋白B(ApoB)较干预组和对照组高;血清铜、锌、硒含量对照组最高、干预组次之、接触组最低。[结论]接触CS2对作业工人血脂和血清微量元素有一定影响。

  5. Investigation and analysis of reference intervals of whole blood viscosity of 137 clinical laboratories in China%全国137家临床实验室全血黏度参考区间的现况调查和分析研究

    Institute of Scientific and Technical Information of China (English)

    费阳; 王薇; 钟堃; 何法霖; 王治国

    2016-01-01

    Objective To investigate the current situation of reference intervals of whole blood viscosity in 137 clinical laboratories all over China and obtain related information to promote the further harmonization of reference intervals .Methods The information of reference intervals was collected by external quality assessment software sys‐tem based on website .The participants were classified due to the instrument they used .SPSS 13 .0 were used to ana‐lyse the results of all laboratories and the reference intervals of each instrument group were statistically described due to the instrument .Results Laboratories paticipating in the ESR reference interval were 137 .The reference intervals of instructions of reagent and instrument manufactures were the highest(81 .02% ,111/137)and the following order was their own laboratory(10 .95% ,15/137) ,national Guide to Clinical Laboratory Procedures(4 .38% ,6/137) and others(3 .65% ,5/137) in turn .Only 48 .18% (66/137)of labs had verified reference intervals before useing .Most of our participant laboratories had considered different gender when establishing reference intervals .There were signifi‐cant differences between the reference intervals of different instrument groups .Conclusion Clinical laboratories should establish the reference intervals of whole blood viscosity on the basis of relevant laws or at least be able to verify the reference interval obtained by other means .Laboratories should communicate positively with clinicians and get consensus on the reference intervals of whole blood viscosity .%目的:调查全国范围内137家实验室全血黏度参考区间现状,期望得到合血黏度参考区间相关资料并为其参考区间的进一步规范化提供基础。方法采用基于 Web 方式的室间质量评价软件系统,收集参加2014年全血黏度参考区间调查室间质量评价计划的所有实验室的结果。使用 SPSS 13.0统计软件对所有实验室结果进行分析,

  6. Intrinsic viscosity of a suspension of cubes

    KAUST Repository

    Mallavajula, Rajesh K.

    2013-11-06

    We report on the viscosity of a dilute suspension of cube-shaped particles. Irrespective of the particle size, size distribution, and surface chemistry, we find empirically that cubes manifest an intrinsic viscosity [η]=3.1±0.2, which is substantially higher than the well-known value for spheres, [η]=2.5. The orientation-dependent intrinsic viscosity of cubic particles is determined theoretically using a finite-element solution of the Stokes equations. For isotropically oriented cubes, these calculations show [η]=3.1, in excellent agreement with our experimental observations. © 2013 American Physical Society.

  7. Shear viscosity of liquid mixtures Mass dependence

    CERN Document Server

    Kaushal, R

    2002-01-01

    Expressions for zeroth, second, and fourth sum rules of transverse stress autocorrelation function of two component fluid have been derived. These sum rules and Mori's memory function formalism have been used to study shear viscosity of Ar-Kr and isotopic mixtures. It has been found that theoretical result is in good agreement with the computer simulation result for the Ar-Kr mixture. The mass dependence of shear viscosity for different mole fraction shows that deviation from ideal linear model comes even from mass difference in two species of fluid mixture. At higher mass ratio shear viscosity of mixture is not explained by any of the emperical model.

  8. Sludge based Bacillus thuringiensis biopesticides: viscosity impacts.

    Science.gov (United States)

    Brar, S K; Verma, M; Tyagi, R D; Valéro, J R; Surampalli, R Y

    2005-08-01

    Viscosity studies were performed on raw, pre-treated (sterilised and thermal alkaline hydrolysed or both types of treatment) and Bacillus thuringiensis (Bt) fermented sludges at different solids concentration (10-40 g/L) for production of biopesticides. Correlations were established among rheological parameter (viscosity), solids (total and dissolved) concentration and entomotoxicity (Tx) of Bt fermented sludges. Exponential and power laws were preferentially followed by hydrolysed fermented compared to raw fermented sludge. Soluble chemical oxygen demand variation corroborated with increase in dissolved solids concentration on pre-treatments, contributing to changes in viscosity. Moreover, Tx was higher for hydrolysed fermented sludge in comparison to raw fermented sludge owing to increased availability of nutrients and lower viscosity that improved oxygen transfer. The shake flask results were reproducible in fermenter. This study will have major impact on selecting fermentation, harvesting and formulation techniques of Bt fermented sludges for biopesticide production.

  9. Neoclassical Viscosities and Anomalous Flows in Stellarators

    Science.gov (United States)

    Ware, A. S.; Spong, D. A.; Breyfogle, M.; Marine, T.

    2009-05-01

    We present initial work to use neoclassical viscosities calculated with the PENTA code [1] in a transport model that includes Reynolds stress generation of flows [2]. The PENTA code uses a drift kinetic equation solver to calculate neoclassical viscosities and flows in general three-dimensional geometries over a range of collisionalities. The predicted neoclassical viscosities predicted by PENTA can be flux-surfaced average and applied in a 1-D transport model that includes anomalous flow generation. This combination of codes can be used to test the impact of stellarator geometry on anomalous flow generation. As a test case, we apply the code to modeling flows in the HSX stellarator. Due to variations in the neoclassical viscosities, HSX can have strong neoclassical flows in the core region. In turn, these neoclassical flows can provide a seed for anomalous flow generation. [1] D. A. Spong, Phys. Plasmas 12, 056114 (2005). [2] D. E. Newman, et al., Phys. Plasmas 5, 938 (1998).

  10. An approximate Expression for Viscosity of Nanosuspensions

    CERN Document Server

    Domostroeva, N G

    2009-01-01

    We consider liquid suspensions with dispersed nanoparticles. Using two-points Pade approximants and combining results of both hydrodynamic and molecular dynamics methods, we obtain the effective viscosity for any diameters of nanoparticles

  11. Quartz resonator fluid density and viscosity monitor

    Science.gov (United States)

    Martin, Stephen J.; Wiczer, James J.; Cernosek, Richard W.; Frye, Gregory C.; Gebert, Charles T.; Casaus, Leonard; Mitchell, Mary A.

    1998-01-01

    A pair of thickness-shear mode resonators, one smooth and one with a textured surface, allows fluid density and viscosity to be independently resolved. A textured surface, either randomly rough or regularly patterned, leads to trapping of liquid at the device surface. The synchronous motion of this trapped liquid with the oscillating device surface allows the device to weigh the liquid; this leads to an additional response that depends on liquid density. This additional response enables a pair of devices, one smooth and one textured, to independently resolve liquid density and viscosity; the difference in responses determines the density while the smooth device determines the density-viscosity product, and thus, the pair determines both density and viscosity.

  12. ANTI-INFLAMMATORY ACTIVITY OF DODONAEA VISCOSE

    OpenAIRE

    Mahadevan, N.; Venkatesh, Sama; Suresh, B

    1998-01-01

    Dodonaea viscose, Linn is a widely grown plant of Nilgiris district of Tamil and is commonly used by the tribals of Nilgiris as a traditional medicine for done fracture and joint sprains. Since it is generally believed tat fractures are accompanied by either some degree of injury or inflammations, it was felt desirable to carry our anti inflammatory activity of Dodonaea viscose. Anti-inflammatory activity of the plant was carried out by carrageenin induced paw edema method in Wister albino rats.

  13. Anti-inflammatory activity of dodonaea viscose.

    Science.gov (United States)

    Mahadevan, N; Venkatesh, S; Suresh, B

    1998-10-01

    Dodonaea viscose, Linn is a widely grown plant of Nilgiris district of Tamil and is commonly used by the tribals of Nilgiris as a traditional medicine for done fracture and joint sprains. Since it is generally believed tat fractures are accompanied by either some degree of injury or inflammations, it was felt desirable to carry our anti inflammatory activity of Dodonaea viscose. Anti-inflammatory activity of the plant was carried out by carrageenin induced paw edema method in Wister albino rats.

  14. Viscosity anomaly in core-softened liquids

    OpenAIRE

    Fomin, Yu. D.; Ryzhov, V. N.

    2013-01-01

    The present article presents a molecular dynamics study of several anomalies of core-softened systems. It is well known that many core-softened liquids demonstrate diffusion anomaly. Usual intuition relates the diffusion coefficient to shear viscosity via Stockes-Einstein relation. However, it can break down at low temperature. In this respect it is important to see if viscosity also demonstrates anomalous behavior.

  15. Blood Types

    Science.gov (United States)

    ... maternity. Learn About Blood Blood Facts and Statistics Blood Components Whole Blood and Red Blood Cells Platelets Plasma ... About Blood Blood Facts and Statistics Blood Types Blood Components What Happens to Donated Blood Blood and Diversity ...

  16. STUDY OF THE VISCOSITY OF PROTEIN SOLUTIONS THROUGH THE RAPID VISCOSITY ANALYZER (RVA

    Directory of Open Access Journals (Sweden)

    Maura P. Alves

    2014-05-01

    Full Text Available This study aimed to determine viscosity curves prepared from whey protein concentrates (WPCs by the rapid viscosity analyzer (RVA and determine the optimal heat treatment time in order to obtain the maximum viscosity solutions at this stage. The WPCs produced from whey samples initially subjected to thermal treatment and microfiltration presented composition compatible with the international standards, with a significant difference (p<0.05 for fat concentration. Viscographic profiles indicated that WPCs produced from microfiltered whey had higher viscosities than those subjected to heat treatment. In addition, 10 min was determined to be the optimal length of time for heat treatment in order to maximise WPCs viscosity. These results indicate that WPC production can be designed for different food applications. Finally, a rapid viscosity analyzer was demonstrated to be an appropriate tool to study the application of whey proteins in food systems.

  17. On the similarity of variable viscosity flows

    Science.gov (United States)

    Voivenel, L.; Danaila, L.; Varea, E.; Renou, B.; Cazalens, M.

    2016-08-01

    Turbulent mixing is ubiquitous in both nature and industrial applications. Most of them concern different fluids, therefore with variable physical properties (density and/or viscosity). The focus here is on variable viscosity flows and mixing, involving density-matched fluids. The issue is whether or not these flows may be self-similar, or self-preserving. The importance of this question stands on the predictability of these flows; self-similar dynamical systems are easier tractable from an analytical viewpoint. More specifically, self-similar analysis is applied to the scale-by-scale energy transport equations, which represent the transport of energy at each scale and each point of the flow. Scale-by-scale energy budget equations are developed for inhomogeneous and anisotropic flows, in which the viscosity varies as a result of heterogeneous mixture or temperature variations. Additional terms are highlighted, accounting for the viscosity gradients, or fluctuations. These terms are present at both small and large scales, thus rectifying the common belief that viscosity is a small-scale quantity. Scale-by-scale energy budget equations are then adapted for the particular case of a round jet evolving in a more viscous host fluid. It is further shown that the condition of self-preservation is not necessarily satisfied in variable-viscosity jets. Indeed, the jet momentum conservation, as well as the constancy of the Reynolds number in the central region of the jet, cannot be satisfied simultaneously. This points to the necessity of considering less stringent conditions (with respect to classical, single-fluid jets) when analytically tackling these flows and reinforces the idea that viscosity variations must be accounted for when modelling these flows.

  18. Viscosity and electric properties of water aerosols

    Science.gov (United States)

    Shavlov, A. V.; Sokolov, I. V.; Dzhumandzhi, V. A.

    2016-09-01

    The flow of water mist in a narrow duct has been studied experimentally. The profile of the velocity of drops has been measured, and the viscosity of the mist has been calculated using the Navier-Stokes equation. It has been found that at low gradients of the rate of shear the viscosity of the mist can exceed that of clean air by tens and even hundreds of times. The electric charge of the drops has been measured. It has been found that the viscosity of the mist differs from that of clean air at gradients of the rate of shear that are less than the frequency of the establishment of electric equilibrium between the drops. A comparative analysis of the viscosities of the mist and a drop cluster has been carried out, and the dependence of the viscosity of the water aerosol on the radius and the charge of the drops has been predicted. The possible role of aerosols that contain submicron drops in the known "clear air turbulence" problem has been shown.

  19. Viscosity of confined inhomogeneous nonequilibrium fluids.

    Science.gov (United States)

    Zhang, Junfang; Todd, B D; Travis, Karl P

    2004-12-01

    We use the nonlocal linear hydrodynamic constitutive model, proposed by Evans and Morriss [Statistical Mechanics of Nonequilibrium Liquids (Academic, London, 1990)], for computing an effective spatially dependent shear viscosity of inhomogeneous nonequilibrium fluids. The model is applied to a simple atomic fluid undergoing planar Poiseuille flow in a confined channel of several atomic diameters width. We compare the spatially dependent viscosity with a local generalization of Newton's law of viscosity and the Navier-Stokes viscosity, both of which are known to suffer extreme inaccuracies for highly inhomogeneous systems. The nonlocal constitutive model calculates effective position dependent viscosities that are free from the notorious singularities experienced by applying the commonly used local constitutive model. It is simple, general, and has widespread applicability in nanofluidics where experimental measurement of position dependent transport coefficients is currently inaccessible. In principle the method can be used to predict approximate flow profiles of any arbitrary inhomogeneous system. We demonstrate this by predicting the flow profile for a simple fluid undergoing planar Couette flow in a confined channel of several atomic diameters width.

  20. High temperature viscosity measurement system and viscosity of a common dielectric liquid

    CERN Document Server

    Tuncer, Enis

    2013-01-01

    A device to measure viscosity of dielectric oils was developed. The device is an inset to an autoclave system where the temperature and the pressure could be controlled. The device is capable of measuring viscosities up to 400C and 5000psi, which are the limits of our autoclave at the moment.

  1. Viscosity jump in Earth's mid-mantle.

    Science.gov (United States)

    Rudolph, Maxwell L; Lekić, Vedran; Lithgow-Bertelloni, Carolina

    2015-12-11

    The viscosity structure of Earth's deep mantle affects the thermal evolution of Earth, the ascent of mantle plumes, settling of subducted oceanic lithosphere, and the mixing of compositional heterogeneities in the mantle. Based on a reanalysis of the long-wavelength nonhydrostatic geoid, we infer viscous layering of the mantle using a method that allows us to avoid a priori assumptions about its variation with depth. We detect an increase in viscosity at 800- to 1200-kilometers depth, far greater than the depth of the mineral phase transformations that define the mantle transition zone. The viscosity increase is coincident in depth with regions where seismic tomography has imaged slab stagnation, plume deflection, and changes in large-scale structure and offers a simple explanation of these phenomena.

  2. Relativistic r-modes and shear viscosity

    CERN Document Server

    Gualtieri, L; Miralles, J A; Ferrari, V

    2006-01-01

    We derive the relativistic equations for stellar perturbations, including in a consistent way shear viscosity in the stress-energy tensor, and we numerically integrate our equations in the case of large viscosity. We consider the slow rotation approximation, and we neglect the coupling between polar and axial perturbations. In our approach, the frequency and damping time of the emitted gravitational radiation are directly obtained. We find that, approaching the inviscid limit from the finite viscosity case, the continuous spectrum is regularized. Constant density stars, polytropic stars, and stars with realistic equations of state are considered. In the case of constant density stars and polytropic stars, our results for the viscous damping times agree, within a factor two, with the usual estimates obtained by using the eigenfunctions of the inviscid limit. For realistic neutron stars, our numerical results give viscous damping times with the same dependence on mass and radius as previously estimated, but sys...

  3. Viscosity near Earth's solid inner core

    Science.gov (United States)

    Smylie

    1999-04-16

    Anomalous splitting of the two equatorial translational modes of oscillation of Earth's solid inner core is used to estimate the effective viscosity just outside its boundary. Superconducting gravimeter observations give periods of 3.5822 +/- 0.0012 (retrograde) and 4.0150 +/- 0.0010 (prograde) hours. With the use of Ekman layer theory to estimate viscous drag forces, an inferred single viscosity of 1.22 x 10(11) Pascal seconds gives calculated periods of 3.5839 and 4.0167 hours for the two modes, close to the observed values. The large effective viscosity is consistent with a fluid, solid-liquid mixture surrounding the inner core associated with the "compositional convection" that drives Earth's geodynamo.

  4. Experimental study on the pressure and pulse wave propagation in viscoelastic vessel tubes-effects of liquid viscosity and tube stiffness.

    Science.gov (United States)

    Ikenaga, Yuki; Nishi, Shohei; Komagata, Yuka; Saito, Masashi; Lagrée, Pierre-Yves; Asada, Takaaki; Matsukawa, Mami

    2013-11-01

    A pulse wave is the displacement wave which arises because of ejection of blood from the heart and reflection at vascular bed and distal point. The investigation of pressure waves leads to understanding the propagation characteristics of a pulse wave. To investigate the pulse wave behavior, an experimental study was performed using an artificial polymer tube and viscous liquid. A polyurethane tube and glycerin solution were used to simulate a blood vessel and blood, respectively. In the case of the 40 wt% glycerin solution, which corresponds to the viscosity of ordinary blood, the attenuation coefficient of a pressure wave in the tube decreased from 4.3 to 1.6 dB/m because of the tube stiffness (Young's modulus: 60 to 200 kPa). When the viscosity of liquid increased from approximately 4 to 10 mPa·s (the range of human blood viscosity) in the stiff tube, the attenuation coefficient of the pressure wave changed from 1.6 to 3.2 dB/m. The hardening of the blood vessel caused by aging and the increase of blood viscosity caused by illness possibly have opposite effects on the intravascular pressure wave. The effect of the viscosity of a liquid on the amplitude of a pressure wave was then considered using a phantom simulating human blood vessels. As a result, in the typical range of blood viscosity, the amplitude ratio of the waves obtained by the experiments with water and glycerin solution became 1:0.83. In comparison with clinical data, this value is much smaller than that seen from blood vessel hardening. Thus, it can be concluded that the blood viscosity seldom affects the attenuation of a pulse wave.

  5. Viscosity Meaurement Technique for Metal Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Ban, Heng [Utah State Univ., Logan, UT (United States). Mechanical and Aerospace Engineering; Kennedy, Rory [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-02-09

    Metallic fuels have exceptional transient behavior, excellent thermal conductivity, and a more straightforward reprocessing path, which does not separate out pure plutonium from the process stream. Fabrication of fuel containing minor actinides and rare earth (RE) elements for irradiation tests, for instance, U-20Pu-3Am-2Np-1.0RE-15Zr samples at the Idaho National Laboratory, is generally done by melt casting in an inert atmosphere. For the design of a casting system and further scale up development, computational modeling of the casting process is needed to provide information on melt flow and solidification for process optimization. Therefore, there is a need for melt viscosity data, the most important melt property that controls the melt flow. The goal of the project was to develop a measurement technique that uses fully sealed melt sample with no Americium vapor loss to determine the viscosity of metallic melts and at temperatures relevant to the casting process. The specific objectives of the project were to: develop mathematical models to establish the principle of the measurement method, design and build a viscosity measurement prototype system based on the established principle, and calibrate the system and quantify the uncertainty range. The result of the project indicates that the oscillation cup technique is applicable for melt viscosity measurement. Detailed mathematical models of innovative sample ampoule designs were developed to not only determine melt viscosity, but also melt density under certain designs. Measurement uncertainties were analyzed and quantified. The result of this project can be used as the initial step toward the eventual goal of establishing a viscosity measurement system for radioactive melts.

  6. Entropy viscosity method for nonlinear conservation laws

    KAUST Repository

    Guermond, Jean-Luc

    2011-05-01

    A new class of high-order numerical methods for approximating nonlinear conservation laws is described (entropy viscosity method). The novelty is that a nonlinear viscosity based on the local size of an entropy production is added to the numerical discretization at hand. This new approach does not use any flux or slope limiters, applies to equations or systems supplemented with one or more entropy inequalities and does not depend on the mesh type and polynomial approximation. Various benchmark problems are solved with finite elements, spectral elements and Fourier series to illustrate the capability of the proposed method. © 2010 Elsevier Inc.

  7. Measuring Viscosities of Gases at Atmospheric Pressure

    Science.gov (United States)

    Singh, Jag J.; Mall, Gerald H.; Hoshang, Chegini

    1987-01-01

    Variant of general capillary method for measuring viscosities of unknown gases based on use of thermal mass-flowmeter section for direct measurement of pressure drops. In technique, flowmeter serves dual role, providing data for determining volume flow rates and serving as well-characterized capillary-tube section for measurement of differential pressures across it. New method simple, sensitive, and adaptable for absolute or relative viscosity measurements of low-pressure gases. Suited for very complex hydrocarbon mixtures where limitations of classical theory and compositional errors make theoretical calculations less reliable.

  8. Shear Viscosity in a Gluon Gas

    OpenAIRE

    Xu, Zhe; Greiner, Carsten

    2007-01-01

    The relation of the shear viscosity coefficient to the recently introduced transport rate is derived within relativistic kinetic theory. We calculate the shear viscosity over entropy ratio \\eta/s for a gluon gas, which involves elastic gg-> gg perturbative QCD (PQCD) scatterings as well as inelastic ggggg PQCD bremsstrahlung. For \\alpha_s=0.3 we find \\eta/s=0.13 and for \\alpha_s=0.6, \\eta/s=0.076. The small \\eta/s values, which suggest strongly coupled systems, are due to the gluon bremsstrah...

  9. Slim accretion discs with different viscosity prescriptions

    Energy Technology Data Exchange (ETDEWEB)

    Szuszkiewicz, E. (Max-Planck-Institut fuer Physik und Astrophysik, Garching (Germany, F.R.). Inst. fuer Astrophysik)

    1990-05-15

    The variability of X-ray sources powered by accretion may be connected to thermal instabilities in the innermost parts of slim discs. The time-scales of variability predicted by the theory with the standard {alpha}-viscosity prescription agree with those observed in a wide range of sources. The amplitudes (3-4 orders of magnitude in luminosity) are correctly predicted for X-ray transient sources, but in general are too big for quasars, Seyferts, galactic black hole candidates and LMXBs. We show here that a slight modification of the viscosity prescription can offer a much better agreement with observations. (author).

  10. Gravimetric capillary method for kinematic viscosity measurements

    Science.gov (United States)

    Rosenberger, Franz; Iwan, J.; Alexander, D.; Jin, Wei-Qing

    1992-01-01

    A novel version of the capillary method for viscosity measurements of liquids is presented. Viscosity data can be deduced in a straightforward way from mass transfer data obtained by differential weighing during the gravity-induced flow of the liquid between two cylindrical chambers. Tests of this technique with water, carbon tetrachloride, and ethanol suggest that this arrangement provides an accuracy of about +/- 1 percent. The technique facilitates operation under sealed, isothermal conditions and, thus can readily be applied to reactive and/or high vapor pressure liquids.

  11. Shear Viscosity of a Unitary Fermi Gas

    OpenAIRE

    Wlazłowski, Gabriel; Magierski, Piotr; Drut, Joaquín E.

    2012-01-01

    We present the first ab initio determination of the shear viscosity eta of the Unitary Fermi Gas, based on finite temperature quantum Monte Carlo calculations and the Kubo linear-response formalism. We determine the temperature dependence of the shear viscosity to entropy density ratio eta/s. The minimum of eta/s appears to be located above the critical temperature for the superfluid-to-normal phase transition with the most probable value being eta/s approx 0.2 hbar/kB, which almost saturates...

  12. SOME ASPECTS OF THE REACTIVITY OF PULP INTENDED FOR HIGH-VISCOSITY VISCOSE

    Directory of Open Access Journals (Sweden)

    Linda Ostberg,

    2012-01-01

    Full Text Available The motivation for this study was to reduce the consumption of C2S when preparing high-viscosity viscose by pre-treating two softwood pulps with enzymes prior to the viscose stages. Reactivity was evaluated in two ways, Fock´s test of the pulp and the gamma number of the viscose solution prior to regeneration. Whilst the reactivity of a pulp that had been subjected to enzyme pretreatment increased according to Fock´s test, it did not increase according to the gamma number. This unexpected difference between the two reactivity tests was investigated. It was concluded that Fock´s test measures the extent to which C2S reacts with a pulp sample during a standardized test, whereas the gamma number measures the resulting degree of xanthate substitution on the cellulose backbone. The gamma number was judged to be the more relevant of the two tests, since it reflects the dissolution ability of a pulp in the viscose preparation. A higher gamma number also means that the coagulation time in the spinning process is prolonged; this is beneficial, as it can be used to increase the tenacity of the viscose fibres. Measuring the reactivity according to Fock´s test, on the contrary, provides more dubious results, as the test has no undisputed correlation to the viscose preparation process.

  13. Commensurability Effects in Viscosity of Nanoconfined Water.

    Science.gov (United States)

    Neek-Amal, Mehdi; Peeters, Francois M; Grigorieva, Irina V; Geim, Andre K

    2016-03-22

    The rate of water flow through hydrophobic nanocapillaries is greatly enhanced as compared to that expected from macroscopic hydrodynamics. This phenomenon is usually described in terms of a relatively large slip length, which is in turn defined by such microscopic properties as the friction between water and capillary surfaces and the viscosity of water. We show that the viscosity of water and, therefore, its flow rate are profoundly affected by the layered structure of confined water if the capillary size becomes less than 2 nm. To this end, we study the structure and dynamics of water confined between two parallel graphene layers using equilibrium molecular dynamics simulations. We find that the shear viscosity is not only greatly enhanced for subnanometer capillaries, but also exhibits large oscillations that originate from commensurability between the capillary size and the size of water molecules. Such oscillating behavior of viscosity and, consequently, the slip length should be taken into account in designing and studying graphene-based and similar membranes for desalination and filtration.

  14. Bulk viscosity effects on ultrasonic thermoacoustic instability

    Science.gov (United States)

    Lin, Jeffrey; Scalo, Carlo; Hesselink, Lambertus

    2016-11-01

    We have carried out unstructured fully-compressible Navier-Stokes simulations of a minimal-unit traveling-wave ultrasonic thermoacoustic device in looped configuration. The model comprises a thermoacoustic stack with 85% porosity and a tapered area change to suppress the fundamental standing-wave mode. A bulk viscosity model, which accounts for vibrational and rotational molecular relaxation effects, is derived and implemented via direct modification of the viscous stress tensor, τij ≡ 2 μSij +λ/2 μ ∂uk/∂xk δij , where the bulk viscosity is defined by μb ≡ λ +2/3 μ . The effective bulk viscosity coefficient accurately captures acoustic absorption from low to high ultrasonic frequencies and matches experimental wave attenuation rates across five decades. Using pressure-based similitude, the model was downscaled from total length L = 2 . 58 m to 0 . 0258 m, corresponding to the frequency range f = 242 - 24200 Hz, revealing the effects of bulk viscosity and direct modification of the thermodynamic pressure. Simulations are carried out to limit cycle and exhibit growth rates consistent with linear stability analyses, based on Rott's theory.

  15. Effect of Viscosity on Liquid Curtain Stability

    Science.gov (United States)

    Mohammad Karim, Alireza; Suszynski, Wieslaw; Francis, Lorraine; Carvalho, Marcio; Dow Chemical Company Collaboration; PUC Rio Collaboration; University of Minnesota, Twin Cities Collaboration

    2016-11-01

    The effect of viscosity on the stability of Newtonian liquid curtains was explored by high-speed visualization. Glycerol/water solutions with viscosity ranging from 19.1 to 210 mPa.s were used as coating liquids. The experimental set-up used a slide die delivery and steel tube edge guides. The velocity along curtain at different positions was measured by tracking small particles at different flow conditions. The measurements revealed that away from edge guides, velocity is well described by free fall effect. However, close to edge guides, liquid moves slower, revealing formation of a viscous boundary layer. The size of boundary layer and velocity near edge guides are strong function of viscosity. The critical condition was determined by examining flow rate below which curtain broke. Curtain failure was initiated by growth of a hole within liquid curtain, close to edge guides. Visualization results showed that the hole forms in a circular shape then becomes elliptical as it grows faster in vertical direction compared to horizontal direction. As viscosity rises, minimum flow rate for destabilization of curtain increased, indicating connection between interaction with edge guides and curtain stability. We would like to acknowledge the financial support from the Dow Chemical Company.

  16. Uniaxial Elongational viscosity of bidisperse polystyrene melts

    DEFF Research Database (Denmark)

    Nielsen, Jens Kromann; Rasmussen, Henrik K.; Hassager, Ole

    2006-01-01

    The startup and steady uniaxial elongational viscosity have been measured for three bidisperse polystyrene (PS) melts, consisting of blends of monodisperse PS with molecular weights of 52 kg/mole or 103 kg/mole and 390 kg/mole. The bidisperse melts have a maximum in the steady elongational viscos...

  17. Shear Viscosity of Turbulent Chiral Plasma

    CERN Document Server

    Kumar, Avdhesh; Das, Amita; Kaw, P K

    2016-01-01

    It is well known that the difference between the chemical potentials of left-handed and right-handed particles in a parity violating (chiral) plasma can lead to an instability. We show that the chiral instability may drive turbulent transport. Further we estimate the anomalous viscosity of chiral plasma arising from the enhanced collisionality due to turbulence.

  18. Viscosity in accretion discs. [for binary stars

    Science.gov (United States)

    Katz, J. I.

    1980-01-01

    Both HerX-1 and SS433 may contain accretion disks slaved to a precessing companion star. If so, it is possible to bound the effective viscosity in these disks. The results, in terms of the disk parameter alpha, are lower bounds of 0.01 for HerX-1 and of 0.1 for SS433.

  19. Pressure-viscosity coefficient of biobased lubricants

    Science.gov (United States)

    Film thickness is an important tribological property that is dependent on the combined effect of lubricant properties, material property of friction surfaces, and the operating conditions of the tribological process. Pressure-viscosity coefficient (PVC) is one of the lubricant properties that influe...

  20. Viscose and Terylene Market Witnesses Positive Activity

    Institute of Scientific and Technical Information of China (English)

    Hua xiaowei; Guoyun

    2010-01-01

    @@ Viscose and terylene staple fiber market is very hot as prices rise this year. The main reason for the positive market activity is that cotton prices hay increased rapidly. But, there is a worry that the appreciation of the yuan, to gether with the rate hike will squeeze profit margins of the industry.

  1. Sensor for Viscosity and Shear Strength Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Dillon, J.; Moore, J.E. Jr.; Ebadian, M.A.; Jones, W.K.

    1998-10-20

    Measurement of the physical properties (viscosity and density) of waste slurries is critical in evaluating transport parameters to ensure turbulent flow through transport pipes. The environment for measurement and sensor exposure is extremely harsh; therefore, reliability and ruggedness are critical in the sensor design. The work for this project will be performed in three phases. The first phase, carried out in FY96, involved (1) an evaluation of acoustic and other methods for viscosity measurement; (2) measurement of the parameters of slurries over the range of percent solids found in tanks and transport systems; (3) a comparison of physical properties (e.g., viscosity and density) to percent solids found composition; and (4) the design of a prototype sensor. The second phase (FY97) will involve the fabrication of a prototype hybrid sensor to measure the viscosity and mechanical properties of slurries in remote, high-radiation environments. Two different viscometer designs are being investigated in this study: a magnetostrictive pulse wave guide viscometer; an oscillating cylinder viscometer. In FY97, the Hemispheric Center for Environmental Technology (HCET) at Florida International University (FIU), which has printed circuit, thick film, thin film, and co-fired ceramic fabrication capability, will fabricate five probes for demonstration after technology selection and evaluation.

  2. Spiders Tune Glue Viscosity to Maximize Adhesion.

    Science.gov (United States)

    Amarpuri, Gaurav; Zhang, Ci; Diaz, Candido; Opell, Brent D; Blackledge, Todd A; Dhinojwala, Ali

    2015-11-24

    Adhesion in humid conditions is a fundamental challenge to both natural and synthetic adhesives. Yet, glue from most spider species becomes stickier as humidity increases. We find the adhesion of spider glue, from five diverse spider species, maximizes at very different humidities that matches their foraging habitats. By using high-speed imaging and spreading power law, we find that the glue viscosity varies over 5 orders of magnitude with humidity for each species, yet the viscosity at maximal adhesion for each species is nearly identical, 10(5)-10(6) cP. Many natural systems take advantage of viscosity to improve functional response, but spider glue's humidity responsiveness is a novel adaptation that makes the glue stickiest in each species' preferred habitat. This tuning is achieved by a combination of proteins and hygroscopic organic salts that determines water uptake in the glue. We therefore anticipate that manipulation of polymer-salts interaction to control viscosity can provide a simple mechanism to design humidity responsive smart adhesives.

  3. Constraints on Crustal Viscosity from Geodetic Observations

    Science.gov (United States)

    Houseman, Gregory

    2015-04-01

    Laboratory measurements of the ductile deformation of crustal rocks demonstrate a range of crystal deformation mechanisms that may be represented by a viscous deformation law, albeit one in which the effective viscosity may vary by orders of magnitude, depending on temperature, stress, grain size, water content and other factors. In such measurements these factors can be separately controlled and effective viscosities can be estimated more or less accurately, though the measured deformation occurs on much shorter time scales and length scales than are typical of geological deformation. To obtain bulk measures of the in situ crustal viscosity law for actual geological processes, estimated stress differences are balanced against measured surface displacement or strain rates: at the continental scale, surface displacement and strain rates can be effectively measured using GPS, and stress differences can be estimated from the distribution of gravitational potential energy; this method has provided constraints on a depth-averaged effective viscosity for the lithosphere as a whole in regions that are actively deforming. Another technique measures the post-seismic displacements that are interpreted to occur in the aftermath of a large crustal earthquake. Stress-differences here are basically constrained by the co-seismic deformation and the elastic rigidity (obtained from seismic velocity) and the strain rates are again provided by GPS. In this technique the strain is a strong function of position relative to the fault, so in general the interpretation of this type of data depends on a complex calculation in which various simplifying assumptions must be made. The spatial variation of displacement history on the surface in this case contains information about the spatial variation of viscosity within the crust. Recent post-seismic studies have shown the potential for obtaining measurements of both depth variation and lateral variation of viscosity in the crust beneath

  4. Does Reactive Thrombocytosis Observed in Iron Deficiency Anemia Affect Plasma Viscosity?

    Directory of Open Access Journals (Sweden)

    Selami K. Toprak

    2012-09-01

    Full Text Available OBJECTIVE: The accompanying thrombocytosis is referred to as the major factor associated with thromboembolism in iron deficiency anemia (IDA. Increased viscosity may increase the risk of thrombosis. We hypothesized that increased platelet count -with reactive thrombocytosis- might also affect plasma viscosity. We planned to evaluate the influence of normal and high platelet count on plasma viscosity in IDA patients. METHODS: The patient population consisted of fifty-three newly diagnosed and untreated women aged between 18 and 62 years with IDA. Group 1 consisted of 33 patients, platelet levels below 400 x 109/L. Group 2 consisted of 20 patients, platelet levels above 400 x 109/L. Measurements of plasma viscosity were performed using Brookfield viscometer. RESULTS: Mean plasma viscosity was found as 1.05 ± 0.08 mPa.s. in Group 1, and 1.03 ± 0.06 mPa.s. in Group 2. Mean plasma viscosity was not statistically different. White blood cell count was significantly higher in Group 2. Vitamin B12 levels were significantly higher in Group 2, while folic acid levels were higher in Group 1 (p=0.011 and p=0.033. Plasma viscosity was correlated with erythrocyte sedimentation rate (r=0.512 p=0.002 in Group 1 and inversely correlated with vitamin B12 (r=−0.480 p=0.032 in Group 2. CONCLUSION: Despite the significant difference between groups in terms of platelet count, no significant difference was detected in plasma viscosity and this finding could be explained as the following; 1-These platelets were not thrombocythemic platelets; 2-Similar to the theory about leukocytes, higher platelet counts – even non-thrombocythemic – may increase plasma viscosity; 3-Evaluating platelet count alone is not sufficient and the associating red-cell deformability should also be taken into account; and 4-Although other diseases that could affect viscosity are excluded, some definitely proven literature criteria such as fibrinogen, hyperlipidemia, and the inflammatory

  5. Response of cardiac endothelial nitric oxide synthase to plasma viscosity modulation in acute isovolemic hemodilution

    Directory of Open Access Journals (Sweden)

    Kanyanatt Kanokwiroon

    2014-01-01

    Full Text Available Background: Endothelial nitric oxide synthase (eNOS is generally expressed in endocardial cells, vascular endothelial cells and ventricular myocytes. However, there is no experimental study elucidating the relationship between cardiac eNOS expression and elevated plasma viscosity in low oxygen delivery pathological conditions such as hemorrhagic shock-resuscitation and hemodilution. This study tested the hypothesis that elevated plasma viscosity increases cardiac eNOS expression in a hemodilution model, leading to positive effects on cardiac performance. Materials and Methods: Two groups of golden Syrian hamster underwent an acute isovolemic hemodilution where 40% of blood volume was exchanged with 2% (low-viscogenic plasma expander [LVPE] or 6% (high-viscogenic plasma expander [HVPE] of dextran 2000 kDa. In control group, experiment was performed without hemodilution. All groups were performed in awake condition. Experimental parameters, i.e., mean arterial blood pressure (MAP, heart rate, hematocrit, blood gas content and viscosity, were measured. The eNOS expression was evaluated by eNOS Western blot analysis. Results: After hemodilution, MAP decreased to 72% and 93% of baseline in the LVPE and HVPE, respectively. Furthermore, pO 2 in the LVPE group increased highest among the groups. Plasma viscosity in the HVPE group was significantly higher than that in control and LVPE groups. The expression of eNOS in the HVPE group showed higher intensity compared to other groups, especially compared with the control group. Conclusion: Our results demonstrated that cardiac eNOS has responded to plasma viscosity modulation with HVPE and LVPE. This particularly supports the previous studies that revealed the positive effects on cardiac function in animals hemodiluted with HVPE.

  6. [Blood rheologic disorders in patients with polycythemia vera and their correction by therapeutic erythrocytapheresis].

    Science.gov (United States)

    Likhovetskaia, Z M; Prigozhina, T A; Gorbunova, N A; Kalinin, N N; Petrov, M M

    1989-11-01

    The rheologic blood properties were studied in patients with polycythemia vera (PV) before and after erythrocytapheresis. The patients with PV showed a complex of hemorheologic disorders (high blood viscosity at different rates of deviation, intensified red blood cell aggregation, decreased deformability of these cells) found to be implicated in the disease pathogenesis. Erythrocytapheresis promoted the improvement of the rheologic characteristics such as dynamic blood viscosity and the red blood cell aggregation ratio.

  7. Mechanism of viscosity effect on magnetic island rotation

    Energy Technology Data Exchange (ETDEWEB)

    Mikhailovskii, A.B.; Konovalov, S.V. [Institute of Nuclear Fusion, Russian Research Centre ' Kurchatov Institute' , Kurchatov Sq., 1, Moscow (Russian Federation); Pustovitov, V.D. [National Inst. for Fusion Science, Toki, Gifu (Japan); Tsypin, V.S. [Institute of Physics, University of Sao Paulo, Rua do Matao, Travessa R, SP (Brazil)

    2000-04-01

    It is shown that plasma viscosity does not influence the magnetic island rotation directly. Nevertheless, it leads to nonstationarity of the plasma velocity. This nonstationarity is the reason of the viscosity effect on island rotation. (author)

  8. Plasma Viscosity with Mass Transport in Spherical ICF Implosion Simulations

    CERN Document Server

    Vold, Erik L; Ortega, Mario I; Moll, Ryan; Fenn, Daniel; Molvig, Kim

    2015-01-01

    The effects of viscosity and small-scale atomic-level mixing on plasmas in inertial confinement fusion (ICF) currently represent challenges in ICF research. Many current ICF hydrodynamic codes ignore the effects of viscosity though recent research indicates viscosity and mixing by classical transport processes may have a substantial impact on implosion dynamics. We have implemented a Lagrange hydrodynamic code in one-dimensional spherical geometry with plasma viscosity and mass transport and including a three temperature model for ions, electrons, and radiation treated in a gray radiation diffusion approximation. The code is used to study ICF implosion differences with and without plasma viscosity and to determine the impacts of viscosity on temperature histories and neutron yield. It was found that plasma viscosity has substantial impacts on ICF shock dynamics characterized by shock burn timing, maximum burn temperatures, convergence ratio, and time history of neutron production rates. Plasma viscosity reduc...

  9. Viscosity effects in wind wave generation

    CERN Document Server

    Paquier, Anna; Rabaud, Marc

    2016-01-01

    We investigate experimentally the influence of the liquid viscosity on the problem of the generation of waves by a turbulent wind at the surface of a liquid, extending the results of Paquier, Moisy and Rabaud [Phys. Fluids {\\bf 27}, 122103 (2015)] over nearly three decades of viscosity. The surface deformations are measured with micrometer accuracy using the Free-Surface Synthetic Schlieren method. We recover the two regimes of surface deformations previously identified: the wrinkles regime at small wind velocity, resulting from the viscous imprint on the liquid surface of the turbulent fluctuations in the boundary layer, and the regular wave regime at large wind velocity. Below the wave threshold, we find that the characteristic amplitude of the wrinkles scales as $\

  10. Viscosity: From air to hot nuclei

    Indian Academy of Sciences (India)

    Nguyen Dinh Dang

    2014-11-01

    After a brief review of the history of viscosity from classical to quantal fluids, a discussion of how the shear viscosity of a finite hot nucleus is calculated directly from the width and energy of the giant dipole resonance (GDR) of the nucleus is given in this paper. The ratio / with s being the entropy volume density, is extracted from the experimental systematic of GDR in copper, tin and lead isotopes at finite temperature . These empirical results are compared with the results predicted by several independent models, as well as with almost model-independent estimations. Based on these results, it is concluded that the ratio / in medium and heavy nuclei decreases with increasing to reach (1.3−4)$×\\hbar/(4 k_B)$ at = 5 MeV, which is almost the same as that obtained for quark-gluon plasma at > 170 MeV.

  11. Shear Viscosity Coefficient from Microscopic Models

    CERN Document Server

    Muronga, A

    2004-01-01

    The transport coefficient of shear viscosity is studied for a hadron matter through microscopic transport model, the Ultra--relativistic Quantum Molecular Dynamics (UrQMD), using the Green--Kubo formulas. Molecular--dynamical simulations are performed for a system of light mesons in a box with periodic boundary conditions. Starting from an initial state composed of $\\pi, \\eta ,\\omega ,\\rho ,\\phi$ with a uniform phase--space distribution, the evolution takes place through elastic collisions, production and annihilation. The system approaches a stationary state of mesons and their resonances, which is characterized by common temperature. After equilibration, thermodynamic quantities such as the energy density, particle density, and pressure are calculated. From such an equilibrated state the shear viscosity coefficient is calculated from the fluctuations of stress tensor around equilibrium using Green--Kubo relations. We do our simulations here at zero net baryon density so that the equilibration times depend o...

  12. A brief review on viscosity of nanofluids

    Science.gov (United States)

    Mishra, Purna Chandra; Mukherjee, Sayantan; Nayak, Santosh Kumar; Panda, Arabind

    2014-10-01

    Since the past decade, rapid development in nanotechnology has produced several aspects for the scientists and technologists to look into. Nanofluid is one of the incredible outcomes of such advancement. Nanofluids (colloidal suspensions of metallic and nonmetallic nanoparticles in conventional base fluids) are best known for their remarkable change to enhanced heat transfer abilities. Earlier research work has already acutely focused on thermal conductivity of nanofluids. However, viscosity is another important property that needs the same attention due to its very crucial impact on heat transfer. Therefore, viscosity of nanofluids should be thoroughly investigated before use for practical heat transfer applications. In this contribution, a brief review on theoretical models is presented precisely. Furthermore, the effects of nanoparticles' shape and size, temperature, volume concentration, pH, etc. are organized together and reviewed.

  13. Molten Composition B Viscosity at Elevated Temperature

    Science.gov (United States)

    Zerkle, David K.; Núñez, Marcel P.; Zucker, Jonathan M.

    2016-10-01

    A shear-thinning viscosity model is developed for molten Composition B at elevated temperature from analysis of falling ball viscometer data. Results are reported with the system held at 85, 110, and 135°C. Balls of densities of 2.7, 8.0, and 15.6 g/cm3 are dropped to generate a range of strain rates in the material. Analysis of video recordings gives the speed at which the balls fall. Computer simulation of the viscometer is used to determine parameters for a non-Newtonian model calibrated to measured speeds. For the first time, viscosity is shown to be a function of temperature and strain rate-dependent maximum RDX (cyclotrimethylenetrinitramine) particle volume fraction.

  14. Bulk and shear viscosity in Hagedorn fluid

    Energy Technology Data Exchange (ETDEWEB)

    Tawfik, A.; Wahba, M. [Egyptian Center for Theoretical Physics (ECTP), MTI University, Faculty of Engineering, Cairo (Egypt)

    2010-11-15

    Assuming that the Hagedorn fluid composed of known particles and resonances with masses m <2 GeV obeys the first-order theory (Eckart) of relativistic fluid, we discuss the transport properties of QCD confined phase. Based on the relativistic kinetic theory formulated under the relaxation time approximation, expressions for bulk and shear viscosity in thermal medium of hadron resonances are derived. The relaxation time in the Hagedorn dynamical fluid exclusively takes into account the decay and eventually van der Waals processes. We comment on the in-medium thermal effects on bulk and shear viscosity and averaged relaxation time with and without the excluded-volume approach. As an application of these results, we suggest the dynamics of heavy-ion collisions, non-equilibrium thermodynamics and the cosmological models, which require thermo- and hydro-dynamics equations of state. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  15. Bulk and Shear Viscosity in Hagedorn Fluid

    CERN Document Server

    Tawfik, A

    2010-01-01

    Assuming that the Hagedorn fluid composed of known particles and resonances with masses $m<2\\,$GeV obeys the {\\it first-order} theory (Eckart) of relativistic fluid, we discuss the transport properties of QCD confined phase. Based on the relativistic kinetic theory formulated under the relaxation time approximation, expressions for bulk and shear viscosity in thermal medium are derived. The relaxation time in the Hagedorn dynamical fluid exclusively takes into account the decay and eventually van der Waals processes. We comment on the {\\it in-medium} thermal effects on bulk and shear viscosities and averaged relaxation time with and without the excluded-volume approach. As an application of these results, we suggest the dynamics of heavy-ion collisions, non-equlibrium thermodynamics and the cosmological models, which require thermo and hydrodynamics equations of state.

  16. Viscosity estimation for slags containing calcium fluoride

    Institute of Scientific and Technical Information of China (English)

    Qifeng Shu; Jiayun Zhang

    2005-01-01

    Based on recently published experimental data, the Riboud model was modified for viscosity estimation of the slags containing calcium fluoride. The estimated values were in good agreement with measured data. Reasonable estimation can be achieved using the modified Riboud model for mould fluxes and ESR (eletro slag remelting) slags. Especially for ESR slags, the modified Riboud model can provide much more precise values than the original Riboud model.

  17. Effective viscosity of magnetic nanofluids through capillaries.

    Science.gov (United States)

    Patel, Rajesh

    2012-02-01

    The simultaneous effect of magnetic field and temperature on the capillary viscosity of magnetic nanofluid is an important parameter for a new class of applications such as nanoduct flow, nanomotors, micro- and nanofluidic devices, for transformer cooling, magnetic targeted drug delivery, etc. The effective viscosity of a nanofluid is explained based on the rotation of the particles and the effect of torque on it due to an externally applied magnetic field. Two types of fluids are used here, temperature-sensitive and non-temperature-sensitive magnetic nanofluids. In both types of fluids, decrease in effective viscosity with temperature is observed, but in both cases the mechanism for the decrement is quite different. One is due to temperature dependence of the magnetic moment and the other is due to removal of the secondary surfactant. For temperature-sensitive magnetic nanofluids, a Curie temperature of ~80 °C is extracted from this study. For non-temperature-sensitive magnetic nanofluids ~65% of the secondary surfactant is removed for a change in temperature, ΔT = 40 °C. This is analogous with removal of a drug from magnetic particles for targeted drug delivery. Further, a linear dependence of effective viscosity with different capillary size and ξ (angle between magnetic field and flow direction, ξε[0,π/2]) is also observed. This linear dependence can also be a good approximation for the study of magnetic drug targeting, as in the human body the capillaries are of different sizes, and the externally applied magnetic field is not always parallel or perpendicular to the drug flow direction.

  18. On bulk viscosity and moduli decay

    OpenAIRE

    M. Laine

    2010-01-01

    This pedagogically intended lecture, one of four under the header "Basics of thermal QCD", reviews an interesting relationship, originally pointed out by Bodeker, that exists between the bulk viscosity of Yang-Mills theory (of possible relevance to the hydrodynamics of heavy ion collision experiments) and the decay rate of scalar fields coupled very weakly to a heat bath (appearing in some particle physics inspired cosmological scenarios). This topic serves, furthermore, as a platform on whic...

  19. Effects of bulk viscosity on cosmological evolution

    CERN Document Server

    Pimentel, L O; Pimentel, L O; Diaz-Rivera, L M

    1994-01-01

    Abstract:The effect of bulk viscisity on the evolution of the homogeneous and isotropic cosmological models is considered. Solutions are found, with a barotropic equation of state, and a viscosity coefficient that is proportional to a power of the energy density of the universe. For flat space, power law expansions, related to extended inflation are found as well as exponential solutions, related to old inflation; also a solution with expansion that is an exponential of an exponential of the time is found.

  20. Impact of Viscosity on DNA Dynamics

    Institute of Scientific and Technical Information of China (English)

    S. ZDRAVKOVI(C); M. V. SATARI(C)

    2007-01-01

    We study the influence of viscosity on DNA dynamics. By employing the nonlinear Peyrard-Bishop-Dauxois (PBD) model, it is shown that the DNA dynamics can be explained by a solution of a complex nonlinear Schrodinger equation (CNLSE). This is the nonlinear Schrodinger equation (NLSE) with a nonlinear parameter being a complex number. We compare real and imaginary parts of this nonlinear parameter and show that the latter one should not be negligible, which means that the CNLSE should be solved numerically.

  1. Viscosity and Plasticity of Latvian Illite Clays

    OpenAIRE

    2012-01-01

    Due to viscosity and plasticity, clays and clay minerals are used in civil engineering, pottery and also in cosmetics and medicine as thickening agents and emulsion and suspension stabilizers. The rheological properties of clay suspensions are complex. Mostly it is an interaction between mineral composition, clay particle size and pH value and also depends on clay minerals. Clay-water suspension is non-Newtonian fluid showing thixotropic and pseudoplastic properties. Results showed that plast...

  2. Viscosity Solutions for the two-phase Stefan Problem

    CERN Document Server

    Kim, Inwon C

    2010-01-01

    We introduce a notion of viscosity solutions for the two-phase Stefan problem, which incorporates possible existence of a mushy region generated by the initial data. We show that a comparison principle holds between viscosity solutions, and investigate the coincidence of the viscosity solutions and the weak solutions defined via integration by parts. In particular, in the absence of initial mushy region, viscosity solution is the unique weak solution with the same boundary data.

  3. RELAP-7 Numerical Stabilization: Entropy Viscosity Method

    Energy Technology Data Exchange (ETDEWEB)

    R. A. Berry; M. O. Delchini; J. Ragusa

    2014-06-01

    The RELAP-7 code is the next generation nuclear reactor system safety analysis code being developed at the Idaho National Laboratory (INL). The code is based on the INL's modern scientific software development framework, MOOSE (Multi-Physics Object Oriented Simulation Environment). The overall design goal of RELAP-7 is to take advantage of the previous thirty years of advancements in computer architecture, software design, numerical integration methods, and physical models. The end result will be a reactor systems analysis capability that retains and improves upon RELAP5's capability and extends the analysis capability for all reactor system simulation scenarios. RELAP-7 utilizes a single phase and a novel seven-equation two-phase flow models as described in the RELAP-7 Theory Manual (INL/EXT-14-31366). The basic equation systems are hyperbolic, which generally require some type of stabilization (or artificial viscosity) to capture nonlinear discontinuities and to suppress advection-caused oscillations. This report documents one of the available options for this stabilization in RELAP-7 -- a new and novel approach known as the entropy viscosity method. Because the code is an ongoing development effort in which the physical sub models, numerics, and coding are evolving, so too must the specific details of the entropy viscosity stabilization method. Here the fundamentals of the method in their current state are presented.

  4. Cosmological Implications of QGP Bulk Viscosity

    CERN Document Server

    Anand, Sampurn; Bhatt, Jitesh R

    2016-01-01

    Recent studies of the hot QCD matter indicate that the bulk viscosity ($\\zeta$) of quark-gluon plasma (QGP) rises sharply near the critical point of the QCD phase transition. In this work, we show that such a sharp rise of the bulk viscosity will lead to an effective negative pressure near the critical temperature, $T_{c}$ which in turn drives the Universe to inflate. This inflation has a natural graceful exist when the viscous effect evanesce. We estimate that, depending upon the peak value of $\\zeta$, universe expands by a factor of $10$ to $80$ times in a very short span ($\\Delta t\\sim 10^{-8}$ seconds). Another important outcome of the bulk viscosity dominated dynamics is the cavitation of QGP around $T \\sim 1.5T_{c}$. This would lead to the phenomenon of formation of cavitation bubbles within the QGP phase. The above scenario is independent of the order of QCD phase transition. We delineate some of the important cosmological consequences of the inflation and the cavitation.

  5. Turbulent viscosity optimized by data assimilation

    Directory of Open Access Journals (Sweden)

    Y. Leredde

    Full Text Available As an alternative approach to classical turbulence modelling using a first or second order closure, the data assimilation method of optimal control is applied to estimate a time and space-dependent turbulent viscosity in a three-dimensional oceanic circulation model. The optimal control method, described for a 3-D primitive equation model, involves the minimization of a cost function that quantifies the discrepancies between the simulations and the observations. An iterative algorithm is obtained via the adjoint model resolution. In a first experiment, a k + L model is used to simulate the one-dimensional development of inertial oscillations resulting from a wind stress at the sea surface and with the presence of a halocline. These results are used as synthetic observations to be assimilated. The turbulent viscosity is then recovered without the k + L closure, even with sparse and noisy observations. The problems of controllability and of the dimensions of the control are then discussed. A second experiment consists of a two-dimensional schematic simulation. A 2-D turbulent viscosity field is estimated from data on the initial and final states of a coastal upwelling event.

    Key words. Oceanography: general (numerical modelling · Oceanography: physical (turbulence · diffusion · and mixing processes

  6. Blood sugar test - blood

    Science.gov (United States)

    ... blood glucose level ( hypoglycemia ) may be due to: Hypopituitarism (a pituitary gland disorder) Underactive thyroid gland or ... tonic-clonic seizure Glucagon blood test Glucagonoma Hyperthyroidism Hypopituitarism Hypothyroidism Insulinoma Low blood sugar Multiple endocrine neoplasia ( ...

  7. Composition and Temperature Dependence of Shear Viscosity of Hydrocarbon Mixtures

    Science.gov (United States)

    1980-07-01

    model for viscosity of liquids , we feel that this is a very good correlation between molecular structure and viscosity, and it appears then that the...B. Thole, "The Viscosity of Liquids ," Longmans, Green and Co., London (1914). 15. W. R. Gambill, Chem. Eng, 66, 151 (1959) 16. P. K. Katti and M. M

  8. ON THE EDDY VISCOSITY MODEL OF PERIODIC TURBULENT SHEAR FLOWS

    Institute of Scientific and Technical Information of China (English)

    王新军; 罗纪生; 周恒

    2003-01-01

    Physical argument shows that eddy viscosity is essentially different from molecular viscosity. By direct numerical simulation, it was shown that for periodic turbulent flows, there is phase difference between Reynolds stress and rate of strain. This finding posed great challenge to turbulence modeling, because most turbulence modeling, which use the idea of eddy viscosity, do not take this effect into account.

  9. Liquid viscosity sensing using nonlinear vibration of a fiberoptic sensor.

    Science.gov (United States)

    Wang, Wei-Chih; Liu, Chao-Shih

    2013-07-01

    This paper investigates the nonlinear dynamic motion of a vibrating optical fiber viscosity sensor through representative cases of primary and super-harmonic resonance. The results show that a nonlinear effect drastically improves the sensitivity of the viscosity measurement by nearly an order of magnitude from the previously developed linear systems. Experimental results and several applications of the viscosity sensor are also presented.

  10. THE RHEOLOGICAL PROPERTIES OF BLOOD IN THE MOST ACUTE STAGE OF ISCHEMIC STROKE AND THEIR RELATION TO THE SEVERITY OF NEUROLOGICAL IMPAIRMENT

    Directory of Open Access Journals (Sweden)

    M. N. Azhermacheva

    2013-01-01

    Full Text Available The study evaluated the rheological parameters of blood: blood viscosity, plasma viscosity, hematocrit, red blood cell aggregation and deformability. The severity of the patients was assessed by clinical scales:Glasgowcoma scale, the scale NIHSS, Barthel index. The study found that in the acute phase of ischemic stroke increased blood viscosity by increasing red blood cell aggregation and reduced erythrocyte deformability. The increase in the viscosity of the blood in acute ischemic stroke is accompanied by increased severity of neurological disorders.

  11. Reference Correlation for the Viscosity of Ethane

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, Eckhard, E-mail: eckhard.vogel@uni-rostock.de [Institut für Chemie, Universität Rostock, D-18059 Rostock (Germany); Span, Roland [Lehrstuhl für Thermodynamik, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Herrmann, Sebastian [Fachgebiet Technische Thermodynamik, Hochschule Zittau/Görlitz, D-02763 Zittau (Germany)

    2015-12-15

    A new representation of the viscosity for the fluid phase of ethane includes a zero-density correlation and a contribution for the critical enhancement, initially both developed separately, but based on experimental data. The higher-density contributions are correlated as a function of the reduced density δ = ρ/ρ{sub c} and of the reciprocal reduced temperature τ = T{sub c}/T (ρ{sub c}—critical density and T{sub c}—critical temperature). The final formulation contains 14 coefficients obtained using a state-of-the-art linear optimization algorithm. The evaluation and choice of the selected primary data sets is reviewed, in particular with respect to the assessment used in earlier viscosity correlations. The new viscosity surface correlation makes use of the reference equation of state for the thermodynamic properties of ethane by Bücker and Wagner [J. Phys. Chem. Ref. Data 35, 205 (2006)] and is valid in the fluid region from the melting line to temperatures of 675 K and pressures of 100 MPa. The viscosity in the limit of zero density is described with an expanded uncertainty of 0.5% (coverage factor k = 2) for temperatures 290 < T/K < 625, increasing to 1.0% at temperatures down to 212 K. The uncertainty of the correlated values is 1.5% in the range 290 < T/K < 430 at pressures up to 30 MPa on the basis of recent measurements judged to be very reliable as well as 4.0% and 6.0% in further regions. The uncertainty in the near-critical region (1.001 < 1/τ < 1.010 and 0.8 < δ < 1.2) increases with decreasing temperature up to 3.0% considering the available reliable data. Tables of the viscosity calculated from the correlation are listed in an appendix for the single-phase region, for the vapor–liquid phase boundary, and for the near-critical region.

  12. Effect of non-Newtonian viscosity on the fluid-dynamic characteristics in stenotic vessels

    Science.gov (United States)

    Huh, Hyung Kyu; Ha, Hojin; Lee, Sang Joon

    2015-08-01

    Although blood is known to have shear-thinning and viscoelastic properties, the effects of such properties on the hemodynamic characteristics in various vascular environments are not fully understood yet. For a quantitative hemodynamic analysis, the refractive index of a transparent blood analogue needs to be matched with that of the flowing conduit in order to minimize the errors according to the distortion of the light. In this study, three refractive index-matched blood analogue fluids with different viscosities are prepared—one Newtonian and two non-Newtonian analogues—which correspond to healthy blood with 45 % hematocrit (i.e., normal non-Newtonian) and obese blood with higher viscosity (i.e., abnormal non-Newtonian). The effects of the non-Newtonian rheological properties of the blood analogues on the hemodynamic characteristics in the post-stenosis region of an axisymmetric stenosis model are experimentally investigated using particle image velocimetry velocity field measurement technique and pathline flow visualization. As a result, the centerline jet flow from the stenosis apex is suppressed by the shear-thinning feature of the blood analogues when the Reynolds number is smaller than 500. The lengths of the recirculation zone for abnormal and normal non-Newtonian blood analogues are 3.67 and 1.72 times shorter than that for the Newtonian analogue at Reynolds numbers smaller than 200. The Reynolds number of the transition from laminar to turbulent flow for all blood analogues increases as the shear-thinning feature increases, and the maximum wall shear stresses in non-Newtonian fluids are five times greater than those in Newtonian fluids. However, the shear-thinning effect on the hemodynamic characteristics is not significant at Reynolds numbers higher than 1000. The findings of this study on refractive index-matched non-Newtonian blood analogues can be utilized in other in vitro experiments, where non-Newtonian features dominantly affect the flow

  13. The Role of Viscosity in TATB Hot Spot Ignition

    Energy Technology Data Exchange (ETDEWEB)

    Fried, L E; Zepeda-Ruis, L; Howard, W M; Najjar, F; Reaugh, J E

    2011-08-02

    The role of dissipative effects, such as viscosity, in the ignition of high explosive pores is investigated using a coupled chemical, thermal, and hydrodynamic model. Chemical reactions are tracked with the Cheetah thermochemical code coupled to the ALE3D hydrodynamic code. We perform molecular dynamics simulations to determine the viscosity of liquid TATB. We also analyze shock wave experiments to obtain an estimate for the shock viscosity of TATB. Using the lower bound liquid-like viscosities, we find that the pore collapse is hydrodynamic in nature. Using the upper bound viscosity from shock wave experiments, we find that the pore collapse is closest to the viscous limit.

  14. Non-Newtonian viscosity wedge in film formation of EHL

    Institute of Scientific and Technical Information of China (English)

    GUOF.; WONGP.L.

    2001-01-01

    This paper aims to evaluate the action of viscosity wedge in the oil film formation ofEHL at opposite sliding and zero entrainment. Using solvers developed for Newtonian and Eyringfluids, the film formation behavior originating from viscosity wedge is investigated. The numericalsimulation displays that lubricant film formation induced by viscosity wedge is different from that bythe well-known geometrical wedge with entrainment in classic EHL. The numerical analyses showthat at high opposite sliding speed the viscosity wedge acts as a leading role in film formation, thenon-Newtonian effects can have a pronounced influence on action of the viscosity wedge.

  15. Effect of nuclear viscosity on fission process

    Energy Technology Data Exchange (ETDEWEB)

    Li Shidong; Kuang Huishun; Zhang Shufa; Xing Jingru; Zhuo Yizhong; Wu Xizhen; Feng Renfa

    1989-02-01

    According to the fission diffusion model, the deformation motion of fission nucleuses is regarded as a diffusion process of quasi-Brownian particles under fission potential. Through simulating such Brownian motion in two dimensional phase space by Monte-Carlo mehtod, the effect of nuclear visocity on Brownian particle diffusion is studied. Dynamical quanties, such as fission rate, kinetic energy distribution on scission, and soon are numerically calculated for various viscosity coefficients. The results are resonable in physics. This method can be easily extended to deal with multi-dimensional diffusion problems.

  16. From Suitable Weak Solutions to Entropy Viscosity

    KAUST Repository

    Guermond, Jean-Luc

    2010-12-16

    This paper focuses on the notion of suitable weak solutions for the three-dimensional incompressible Navier-Stokes equations and discusses the relevance of this notion to Computational Fluid Dynamics. The purpose of the paper is twofold (i) to recall basic mathematical properties of the three-dimensional incompressible Navier-Stokes equations and to show how they might relate to LES (ii) to introduce an entropy viscosity technique based on the notion of suitable weak solution and to illustrate numerically this concept. © 2010 Springer Science+Business Media, LLC.

  17. Collective excitations and viscosity in liquid Bi

    Science.gov (United States)

    Ropo, Matti; Akola, Jaakko; Jones, R. O.

    2016-11-01

    The analysis of extensive density functional/molecular dynamics simulations (over 500 atoms, up to 100 ps) of liquid bismuth at four temperatures between 573 K and 1023 K has provided details of the dynamical structure factors, the dispersion of longitudinal and transverse collective modes, and related properties (power spectrum, viscosity, and sound velocity). Agreement with available inelastic x-ray and neutron scattering data and with previous simulations is generally very good. The results show that density functional/molecular dynamics simulations can give dynamical information of good quality without the use of fitting functions, even at long wavelengths.

  18. Simultaneous effects of single wall carbon nanotube and effective variable viscosity for peristaltic flow through annulus having permeable walls

    Science.gov (United States)

    Shahzadi, Iqra; Nadeem, S.; Rabiei, Faranak

    The current article deals with the combine effects of single wall carbon nanotubes and effective viscosity for the peristaltic flow of nanofluid through annulus. The nature of the walls is assumed to be permeable. The present theoretical model can be considered as mathematical representation to the motion of conductive physiological fluids in the existence of the endoscope tube which has many biomedical applications such as drug delivery system. The outer tube has a wave of sinusoidal nature that is travelling along its walls while the inner tube is rigid and uniform. Lubrication approach is used for the considered analysis. An empirical relation for the effective variable viscosity of nanofluid is proposed here interestingly. The viscosity of nanofluid is the function of radial distance and the concentration of nanoparticles. Exact solution for the resulting system of equations is displayed for various quantities of interest. The outcomes show that the maximum velocity of SWCNT-blood nanofluid enhances for larger values of viscosity parameter. The pressure gradient in the more extensive part of the annulus is likewise found to increase as a function of variable viscosity parameter. The size of the trapped bolus is also influenced by variable viscosity parameter. The present examination also revealed that the carbon nanotubes have many applications related to biomedicine.

  19. Solvent viscosity dependence for enzymatic reactions

    CERN Document Server

    Sitnitsky, A E

    2008-01-01

    A mechanism for relationship of solvent viscosity with reaction rate constant at enzyme action is suggested. It is based on fluctuations of electric field in enzyme active site produced by thermally equilibrium rocking (cranckshaft motion) of the rigid plane (in which the dipole moment $\\approx 3.6 D$ lies) of a favourably located and oriented peptide group (or may be a few of them). Thus the rocking of the plane leads to fluctuations of the electric field of the dipole moment. These fluctuations can interact with the reaction coordinate because the latter in its turn has transition dipole moment due to separation of charges at movement of the reacting system along it. The rocking of the plane of the peptide group is sensitive to the microviscosity of its environment in protein interior and the latter is a function of the solvent viscosity. Thus we obtain an additional factor of interrelationship for these characteristics with the reaction rate constant. We argue that due to the properties of the cranckshaft ...

  20. Importance of Mantle Viscosity in Interseismic Deformation

    Science.gov (United States)

    Wang, K.; He, J.; Hu, Y.

    2012-12-01

    The role of mantle viscosity in subduction earthquake cycles was postulated when the plate tectonics theory had just gained wide acceptance. The process was described using Elsasser's 1-D model for diffusion of stress from the subduction boundary to the plate interior. Main features of interseismic surface deformation predicted by this elegantly simple model were later verified by GPS observations following giant subduction earthquakes. However, and intriguingly, the vast majority of interseismic deformation models developed in the era of space geodesy assume an elastic Earth, incorrectly regarding interseismic deformation as a subdued mirror image of coseismic deformation. The reason is four-fold. (1) The 1-D model and subsequent 2-D viscoelastic models failed to recognize the role of rupture length in the strike direction and could not self-consistently explain deformation following medium and small earthquakes. (2) Based on global mantle viscosity models derived from glacial isostatic adjustment studies, the viscoelastic mantle should indeed behave elastically in earthquake cycles of a few hundred years. (3) The effect of viscous mantle deformation can often be equivalently described by deep fault creep in a purely elastic Earth. (4) The use of an elastic model provides convenience in inverting geodetic data to determine fault locking and creep. Here we use 3D finite element models to show that the main characteristics of surface deformation following subduction earthquakes of all sizes can be explained with a viscoelastic Earth in which the mantle wedge is less viscous than global upper-mantle average of 1020 - 1021 Pa s by one to two orders of magnitude. Following giant earthquakes, such as 1700 Cascadia, 1960 Chile, 1964 Alaska, 2004 Sumatra, and 2011 Japan, upper-plate land deformation undergoes phases of wholesale seaward motion, opposing motion of coastal and inland areas, and wholesale landward motion. The "speed" of the evolution scales inversely with

  1. Modeling the viscosity of silicate melts containing manganese oxide

    Directory of Open Access Journals (Sweden)

    Kim Wan-Yi

    2013-01-01

    Full Text Available Our recently developed model for the viscosity of silicate melts is applied to describe and predict the viscosities of oxide melts containing manganese oxide. The model requires three pairs of adjustable parameters that describe the viscosities in three systems: pure MnO, MnO-SiO2 and MnO-Al2O3-SiO2. The viscosity of other ternary and multicomponent silicate melts containing MnO is then predicted by the model without any additional adjustable model parameters. Experimental viscosity data are reviewed for melts formed by MnO with SiO2, Al2O3, CaO, MgO, PbO, Na2O and K2O. The deviation of the available experimental data from the viscosities predicted by the model is shown to be within experimental error limits.

  2. EFFECT OF ADSORPTION ON THE VISCOSITY OF DILUTE POLYMER SOLUTION

    Institute of Scientific and Technical Information of China (English)

    Rong-shi Cheng; Yu-fang Shao; Ming-zhu Liu; Rong-qing Lu

    1999-01-01

    Careful measurements of the dilute solution viscosities of polyethylene glycol and polyvinyl alcohol in water were carried out. The reduced viscosities of both polymer solutions plot upward curves at extremely dilute concentration levels similar to the phenomena observed for many polymer solutions in the early 1950's. Upon observation of the changes of the flow times of pure water in and the wall surface wettability of the viscometer after measuring solution viscosity, a view was formed that the observed viscosity abnormality at extremely dilute concentration regions is solely due to the effect of adsorption of polymer chains onto the wall surface of viscometer. A theory of adsorption effect based on the Langmuir isotherms was proposed and a mathematical analysis for data treatment was performed. The theory could adequately describe the existing viscosity data. It seems necessary to correct the viscosity result of dilute polymer solutions measured by glass capillary viscometer by taking into account the effect of adsorption in all cases.

  3. Anomalous Viscosity of the Quark-Gluon Plasma

    CERN Document Server

    Hong, Juhee

    2013-01-01

    The shear viscosity of the quark-gluon plasma is predicted to be lower than the collisional viscosity for weak coupling. The estimated ratio of the shear viscosity to entropy density is rather close to the ratio calculated by N = 4 super Yang-Mills theory for strong coupling, which indicates that the quark-gluon plasma might be strongly coupled. However, in presence of momentum anisotropy, the Weibel instability can arise and affect transport properties. Shear viscosity can be lowered by enhanced collisionality due to turbulence, but the decorrelation time and its relation to underlying dynamics and color-magnetic fields have not been calculated self-consistently. In this paper, we use resonance broadening theory for strong turbulence to calculate the anomalous viscosity of the quark-gluon plasma for nonequilibrium. For saturated Weibel instability, we estimate the scalings of the decorrelation rate and viscosity and compare these with collisional transport. This calculation yields an explicit connection betw...

  4. GodunovSPH with shear viscosity : implementation and tests

    CERN Document Server

    Cha, Seung-Hoon

    2016-01-01

    The acceleration and energy dissipation terms due to the shear viscosity have been implemented and tested in GodunovSPH. The double summation method has been employed to avoid the well known numerical noise of the second derivative in particle based codes. The plane Couette flow with various initial and boundary conditions have been used as tests, and the numerical and analytical results show a good agreement. Not only the viscosity--only calculation, but the full hydrodynamics simulations have been performed, and they show expected results as well. The very low kinematic viscosity simulations show a turbulent pattern when the Reynolds number exceeds $\\sim$$10^2$. The critical value of the Reynolds number at the transition point of the laminar and turbulent flows coincides with the previous works approximately. A smoothed dynamic viscosity has been suggested to describe the individual kinematic viscosity of particles. The infinitely extended Couette flow which has two layers of different viscosities has been ...

  5. Isomorphic Viscosity Equation of State for Binary Fluid Mixtures.

    Science.gov (United States)

    Behnejad, Hassan; Cheshmpak, Hashem; Jamali, Asma

    2015-01-01

    The thermodynamic behavior of the simple binary mixtures in the vicinity of critical line has a universal character and can be mapped from pure components using the isomorphism hypothesis. Consequently, based upon the principle of isomorphism, critical phenomena and similarity between P-ρ-T and T-η-(viscosity)-P relationships, the viscosity model has been developed adopting two cubic, Soave-Redlich-Kwong (SRK) and Peng-Robinson (PR), equations of state (EsoS) for predicting the viscosity of the binary mixtures. This procedure has been applied to the methane-butane mixture and predicted its viscosity data. Reasonable agreement with the experimental data has been observed. In conclusion, we have shown that the isomorphism principle in conjunction with the mapped viscosity EoS suggests a reliable model for calculating the viscosity of mixture of hydrocarbons over a wide pressure range up to 35 MPa within the stated experimental errors.

  6. Viscosity, thermal diffusivity and Prandtl number of nanoparticle suspensions

    Institute of Scientific and Technical Information of China (English)

    WANG Buxuan; ZHOU Leping; PENG Xiaofeng

    2004-01-01

    Using our reported experimental data of effective thermal conductivity, specific heat capacity and viscosity for CuO nanoparticle suspensions, the corresponding thermal diffusivity and Prandtl number are calculated. With the hard sphere model and considering effects of particle clustering and surface adsorption, the increase of viscosity for nanoparticle suspension observed is explained. It is shown that the effective thermal conductivity will be strongly affected by the formation and correlated spatial distribution of nanoparticle clusters when compared to viscosity in hosting liquid.

  7. Modelling viscosity and mass fraction of bitumen - diluent mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Miadonye, A.; Latour, N.; Puttagunta, V.R. [Lakehead Univ., Thunder Bay, ON (Canada)

    1999-07-01

    In recovery of bitumen in oil sands extraction, the reduction of the viscosity is important above and below ground. The addition of liquid diluent breaks down or weakens the intermolecular forces that create a high viscosity in bitumen. The addition of even 5% of diluent can cause a viscosity reduction in excess of 8%, thus facilitating the in situ recovery and pipeline transportation of bitumen. Knowledge of bitumen - diluent viscosity is highly important because without it, determination of upgrading processes, in situ recovery, well simulation, heat transfer, fluid flow and a variety of other engineering problems would be difficult or impossible to solve. The development of a simple correlation to predict the viscosity of binary mixtures of bitumen - diluent in any proportion is described. The developed correlation used to estimate the viscosities and mass fractions of bitumen - diluent mixtures was within acceptable limits of error. For the prediction of mixture viscosities, the developed correlation gave the best results with an overall average absolute deviation of 12% compared to those of Chironis (17%) and Cragoe (23%). Predictions of diluent mass fractions yielded a much better result with an overall average absolute deviation of 5%. The unique features of the correlation include its computational simplicity, its applicability to mixtures at temperatures other than 30 degrees C, and the fact that only the bitumen and diluent viscosities are needed to make predictions. It is the only correlation capable of predicting viscosities of mixtures, as well as diluent mass fractions required to reduce bitumen viscosity to pumping viscosities. The prediction of viscosities at 25, 60.3, and 82.6 degrees C produced excellent results, particularly at high temperatures with an average absolute deviation of below 10%. 11 refs., 3 figs., 8 tabs.

  8. Non-invasive fluid density and viscosity measurement

    Science.gov (United States)

    Sinha, Dipen N.

    2012-05-01

    The noninvasively measurement of the density and viscosity of static or flowing fluids in a section of pipe such that the pipe performs as the sensing apparatus, is described. Measurement of a suitable structural vibration resonance frequency of the pipe and the width of this resonance permits the density and viscosity to be determined, respectively. The viscosity may also be measured by monitoring the decay in time of a vibration resonance in the pipe.

  9. Universe Models with Negative Bulk Viscosity

    CERN Document Server

    Brevik, Iver

    2013-01-01

    The concept of negative temperatures has occasionally been used in connection with quantum systems. A recent example of this sort is reported in the paper of S. Braun et al. [Science 339,52 (2013)], where an attractively interacting ensemble of ultracold atoms is investigated experimentally and found to correspond to a negative-temperature system since the entropy decreases with increasing energy at the high end of the energy spectrum. As the authors suggest, it would be of interest to investigate whether a suitable generalization of standard cosmological theory could be helpful, in order to elucidate the observed accelerated expansion of the universe usually explained in terms of a positive tensile stress (negative pressure). In the present note we take up this basic idea and investigate a generalization of the standard viscous cosmological theory, not by admitting negative temperatures but instead by letting the bulk viscosity take negative values. Evidently, such an approach breaks standard thermodynamics,...

  10. On bulk viscosity and moduli decay

    CERN Document Server

    Laine, M

    2010-01-01

    This pedagogically intended lecture, one of four under the header "Basics of thermal QCD", reviews an interesting relationship, originally pointed out by Bodeker, that exists between the bulk viscosity of Yang-Mills theory (of possible relevance to the hydrodynamics of heavy ion collision experiments) and the decay rate of scalar fields coupled very weakly to a heat bath (appearing in some particle physics inspired cosmological scenarios). This topic serves, futhermore, as a platform on which a number of generic thermal field theory concepts are illustrated. The other three lectures (on the QCD equation of state and the rates of elastic as well as inelastic processes experienced by heavy quarks) are recapitulated in brief encyclopedic form.

  11. Selective Withdrawal with an Inverted Viscosity Ratio

    Science.gov (United States)

    Case, Sarah

    2005-03-01

    In the selective withdrawal experiment, fluid is withdrawn, at rate Q, through a tube with its tip suspended a distance S above an unperturbed interface separating two immiscible fluids. For high Q, the lower fluid is entrained along with the upper one while for low Q only the upper fluid is withdrawn. We have studied the situation where the ratio of lower to the upper fluid viscosities, η>1. For low Q, the interface forms a steady-state hump and only the upper fluid is withdrawn. When Q is increased, or S is decreased, the interface undergoes a two-stage transition: first the hump forms an unsteady, thin spout which then expands into a second thicker steady-state structure with distinct flow patterns in the lower fluid. This thick-spout structure is not observed for ηCohen and S. R. Nagel, Phys. Rev. Lett. 88, 074501 1- 4 (2002).

  12. Holographic bulk viscosity: GPR vs EO

    CERN Document Server

    Buchel, Alex; Kiritsis, Elias

    2011-01-01

    Recently Eling and Oz (EO) proposed a formula for the holographic bulk viscosity, in arXiv:1103.1657, derived from the null horizon focusing equation. This formula seems different from that obtained earlier by Gubser, Pufu and Rocha (GPR) in arXiv:0806.0407 calculated from the IR limit of the two-point function of the trace of the stress tensor. The two were shown to agree only for some simple scaling cases. We point out that the two formulae agree in two non-trivial holographic theories describing RG flows. The first is the strongly coupled N=2* gauge theory plasma. The second is the semi-phenomenological model of Improved Holographic QCD.

  13. Cosmic String Universes Embedded with Viscosity

    Institute of Scientific and Technical Information of China (English)

    Koijam Manihar Singh; Kangujam Priyokumar Singh

    2011-01-01

    We study string cosmological models with attached particles in LRS BI type space time.The dynamical and physical properties of such universes are studied,and the possibility that during the evolution of the universe the strings disappear,leaving only the particles,is also discussed.It is found that bulk viscosity plays a large role in the evolution of the universe.In these models we find critical instances of when there was a “Bounce”.The studied models are found to be of an inflationary type,and since a desirable feature of a meaningful string cosmological model is the presence of an inflationary epoch in the very early stages of evolution,our models can be thought of as realistic universes.The origin of the universe and the early stages of formation are still interesting areas of research.The concept of string theory was developed to describe the events of the early stages of the evolution of the universe.The universe can be described as a collection of extended (non point) objects.Thus,“string dust” cosmology will provide us with a model to investigate the properties related to this fact.%We study string cosmological models with attached particles in LRS BI type space time. The dynamical and physical properties of such universes are studied, and the possibility that during the evolution of the universe the strings disappear, leaving only the particles, is also discussed. It is found that bulk viscosity plays a large role in the evolution of the universe. In these models we find critical instances of when there was a "Bounce". The studied models are found to be of an inflationary type, and since a desirable feature of a meaningful string cosmological model is the presence of an inflationary epoch in the very early stages of evolution, our models can be thought of as realistic universes.

  14. Sensor for viscosity and shear strength measurement

    Energy Technology Data Exchange (ETDEWEB)

    Ebadian, M.A.; Dillion, J.; Moore, J.; Jones, K.

    1998-01-01

    Measurement of the physical properties (viscosity and density) of waste slurries is critical in evaluating transport parameters to ensure turbulent flow through transport pipes. The environment for measurement and sensor exposure is extremely harsh; therefore, reliability and ruggedness are critical in the sensor design. Two different viscometer techniques are being investigated in this study, based on: magnetostrictive pulse generated acoustic waves; and an oscillating cylinder. Prototype sensors have been built and tested which are based on both techniques. A base capability instrumentation system has been designed, constructed, and tested which incorporates both of these sensors. It requires manual data acquisition and off-line calculation. A broad range of viscous media has been tested using this system. Extensive test results appear in this report. The concept for each technique has been validated by these test results. This base capability system will need to be refined further before it is appropriate for field tests. The mass of the oscillating system structure will need to be reduced. A robust acoustic probe assembly will need to be developed. In addition, in March 1997 it was made known for the first time that the requirement was for a deliverable automated viscosity instrumentation system. Since then such a system has been designed, and the hardware has been constructed so that the automated concept can be proved. The rest of the hardware, which interfaced to a computer, has also been constructed and tested as far as possible. However, for both techniques the computer software for automated data acquisition, calculation, and logging had not been completed before funding and time ran out.

  15. Notes on shear viscosity bound violation in anisotropic models

    CERN Document Server

    Ge, Xian-Hui

    2015-01-01

    The shear viscosity bound violation in Einstein gravity for anisotropic black branes is discussed, with the aim of constraining the deviation of the shear viscosity-entropy density ratio from the shear viscosity bound using causality and thermodynamics analysis. The results show that no stringent constraints can be imposed. The diffusion bound in anisotropic phases is also studied. Ultimately, it is concluded that shear viscosity violation always occurs in cases where the equation of motion of the metric fluctuations cannot be written in a form identical to that of the minimally coupled massless scalar fields.

  16. ANALYSIS OF VISCOSITY ABNORMALITIES OF POLYELECTROLYTES IN DILUTE SOLUTIONS

    Institute of Scientific and Technical Information of China (English)

    Jian-qiang Chen; Yu-fang Shao; Zhen Yang; Hu Yang; Rong-shi Cheng

    2011-01-01

    It was found that the interface effects in viscous capillary flow influenced the process of viscosity measurement greatly,and the abnormal viscosity behaviors of polyelectrolytes as well as neutral polymers in dilute solution region were ascribed to interface effect.According to this theory,we have reviewed the previous viscosity data of derivatives of poly-2-vinylpyridine reported by Maclay and Fuoss first.Then,the abnormal viscosity behaviors of a series of sodium polystyrene sulfonate samples with various molecular weights in dilute aqueous solutions were studied further.The solute adsorption behaviors and structural information of polymers have been discussed carefully.

  17. Experimental Viscosity Measurements for Copper Oxide Nanoparticle Suspensions

    Institute of Scientific and Technical Information of China (English)

    李俊明; 李泽梁; 王补宣

    2002-01-01

    The viscosity of water with copper oxide nanoparticle suspensions was measured using capillary viscometers. The mass fractions of copper oxide nanoparticles in the experiment, w, varied between 0.02 and 0.10, and the temperature range was 30℃ to 80℃. The experimental results show that the temperature was the major factor affecting the viscosity of the nanoparticle suspensions, while the effect of the mass fraction on the viscosity was not so obvious as that of the temperature for the mass fractions chosen in the experiment. The effect of the capillary tube size on the viscosity was also found to be relatively important at higher mass fractions.

  18. Heat Transfer Analysis for Peristaltic Mechanism in Variable Viscosity Fluid

    Institute of Scientific and Technical Information of China (English)

    T.Hayat; F.M.Abbasi; Awatif A.Hendi

    2011-01-01

    An analysis is carried out for a peristaltic flow of a third-order fluid with heat transfer and variable viscosity when no-slip condition does not hold. Perturbation solution is discussed and a comparative study between the cases of constant and variable viscosities is presented and analyzed.%@@ An analysis is carried out for a peristaltic flow of a third-order fluid with heat transfer and variable viscosity when no-slip condition does not hold.Perturbation solution is discussed and a comparative stuity between the cases of constant and variable viscosities is presented and analyzed.

  19. Rye affects bacterial translocation, intestinal viscosity, microbiota composition and bone mineralization in Turkey poults.

    Directory of Open Access Journals (Sweden)

    Guillermo Tellez

    Full Text Available Previously, we have reported that rye significantly increased both viscosity and Clostridium perfringens proliferation when compared with corn in an in vitro digestive model. Two independent trials were conducted to evaluate the effect of rye as a source of energy on bacterial translocation, intestinal viscosity, gut microbiota composition, and bone mineralization, when compared with corn in turkey poults. In each experiment, day-of-hatch, turkey poults were randomly assigned to either a corn or a rye diet (n = 0 /group. At 10 d of age, in both experiments, 12 birds/group were given an oral gavage dose of fluorescein isothiocyanate dextran (FITC-d. After 2.5 h of oral gavage, blood and liver samples were collected to evaluate the passage of FITC-d and bacterial translocation (BT respectively. Duodenum, ileum and cecum gut sections were collected to evaluate intestinal viscosity and to enumerate gut microbiota. Tibias were collected for observation of bone parameters. Broilers fed with a rye diet showed increased (p<0.05 intestinal viscosity, BT, and serum FITC-d. Bacterial enumeration revealed that turkey poults fed with rye had increased the number of total lactic acid bacteria (LAB in all three sections of the gastrointestinal tract evaluated when compared to turkey poults fed with corn. Turkey poults fed with rye also had significantly higher coliforms in duodenum and ileum but not in the ceca, whereas the total number of anaerobes increased only in duodenum. A significant reduction in bone strength and bone mineralization was observed in turkey poults fed with rye when compared with corn fed turkey poults. In conclusion, rye evoked mucosal damage in turkey poults that increased intestinal viscosity, increased leakage through the intestinal tract, and altered the microbiota composition and bone mineralization. Studies to evaluate dietary inclusion of selected Direct-Fed Microbial (DFM candidates that produce exogenous enzymes in rye fed

  20. Inference of mantle viscosity for depth resolutions of GIA observations

    Science.gov (United States)

    Nakada, Masao; Okuno, Jun'ichi

    2016-11-01

    Inference of the mantle viscosity from observations for glacial isostatic adjustment (GIA) process has usually been conducted through the analyses based on the simple three-layer viscosity model characterized by lithospheric thickness, upper- and lower-mantle viscosities. Here, we examine the viscosity structures for the simple three-layer viscosity model and also for the two-layer lower-mantle viscosity model defined by viscosities of η670,D (670-D km depth) and ηD,2891 (D-2891 km depth) with D-values of 1191, 1691 and 2191 km. The upper-mantle rheological parameters for the two-layer lower-mantle viscosity model are the same as those for the simple three-layer one. For the simple three-layer viscosity model, rate of change of degree-two zonal harmonics of geopotential due to GIA process (GIA-induced J˙2) of -(6.0-6.5) × 10-11 yr-1 provides two permissible viscosity solutions for the lower mantle, (7-20) × 1021 and (5-9) × 1022 Pa s, and the analyses with observational constraints of the J˙2 and Last Glacial Maximum (LGM) sea levels at Barbados and Bonaparte Gulf indicate (5-9) × 1022 Pa s for the lower mantle. However, the analyses for the J˙2 based on the two-layer lower-mantle viscosity model only require a viscosity layer higher than (5-10) × 1021 Pa s for a depth above the core-mantle boundary (CMB), in which the value of (5-10) × 1021 Pa s corresponds to the solution of (7-20) × 1021 Pa s for the simple three-layer one. Moreover, the analyses with the J˙2 and LGM sea level constraints for the two-layer lower-mantle viscosity model indicate two viscosity solutions: η670,1191 > 3 × 1021 and η1191,2891 ˜ (5-10) × 1022 Pa s, and η670,1691 > 1022 and η1691,2891 ˜ (5-10) × 1022 Pa s. The inferred upper-mantle viscosity for such solutions is (1-4) × 1020 Pa s similar to the estimate for the simple three-layer viscosity model. That is, these analyses require a high viscosity layer of (5-10) × 1022 Pa s at least in the deep mantle, and suggest

  1. Viscosity to entropy ratio of QGP in relativistic heavy ion collisions: The second-order viscose hydrodynamics

    Science.gov (United States)

    Mehrabi Pari, Sharareh; Taghavi Shahri, Fatemeh; Javidan, Kurosh

    2016-10-01

    The nuclear suppression factor RAA and elliptic flow ν2 are calculated by considering the effects of shear viscosity to the entropy density ratio η/s, using the viscose hydrodynamics at the first- and second-orders of approximation and considering temperature dependent coupling αs(T). It is shown that the second-order viscose hydrodynamics (varying shear viscosity to entropy ratio) with averaged value of 4πη/s = 1.5 ± 0.1 gives the best results of RAA and ν2 in comparison to the experimental data.

  2. Rheology and tribology of lubricants with polymeric viscosity modifiers

    Science.gov (United States)

    Babak, LotfizadehDehkordi

    Elastohydrodynamic lubrication (EHL) theory has been used to model the lubrication state of antifriction machine elements, where initial viscosity and pressure viscosity coefficients are essential parameters in film thickness modeling. Since the pressures of lubricants in the contact zone can be very high, it is important to know the rheological properties of lubricants in these pressure and temperature regimes. The characteristics of viscosity behavior as a function of pressure are also essential for a universal definition of the pressure viscosity coefficient in order to estimate film thickness in an EHL regime. In this study, viscosities and pressure-viscosity coefficients of ten commercial engine and gear oils and seventeen laboratory-produced oil/polymer viscosity modifiers (VM) additives are measured up to 1.3 GPa at 40, 75 and 100 °C. For the first time, a sharp increase in the viscosity and piezoviscous factor is observed in both mineral-based and synthetic-based oils with different VMs. Analysis of the experimental results indicates that sharp increase in viscosity observed in these experiments are believed to arise from physical changes in the VMs, that is liquid-solid phase transition. Evidence is offered that polymer properties such as molecular weight, concentration and structure influence the onset of the phase transitions. A modified Yasutomi model, which normally describes the pressure dependence of the viscosity of lubricants very well, fails to predict the viscosity of the specimens above the onset of sharp increase in viscosity. A design of experiment (DOE) analysis using Design-Expert software indicates that pressure and temperature are the most critical parameters in the viscosity variation. Tribological tests demonstrate that wear in the contact, zone occurs at temperatures and stresses that coincides with the VM phase transitions in both commercial and laboratory synthesized oil/VMs. Tribological results also indicate that the onset of the

  3. Vinpocetine and Pyritinol: A New Model for Blood Rheological Modulation in Cerebrovascular Disorders—A Randomized Controlled Clinical Study

    Directory of Open Access Journals (Sweden)

    Hayder M. Alkuraishy

    2014-01-01

    Full Text Available Blood and plasma viscosity are the major factors affecting blood flow and normal circulation. Whole blood viscosity is mainly affected by plasma viscosity, red blood cell deformability/aggregation and hematocrit, and other physiological factors. Thirty patients (twenty males + ten females with age range 50–65 years, normotensive with history of cerebrovascular disorders, were selected according to the American Heart Stroke Association. Blood viscosity and other rheological parameters were measured after two-day abstinence from any medications. Dual effects of vinpocetine and pyritinol exhibit significant effects on all hemorheological parameters (P0.05. Therefore, joint effects of vinpocetine and pyritinol improve blood and plasma viscosity in patients with cerebrovascular disorders.

  4. Improved acoustic viscosimeter technique. [for determining fluid shear viscosity

    Science.gov (United States)

    Fisch, M. R.; Moeller, R. P.; Carome, E. F.

    1976-01-01

    An improved technique has been developed for studies of the shear viscosity of fluids. It utilizes an acoustic resonator as a four-terminal electrical device; the resonator's amplitude response may be determined directly and simply related to the fluid's viscosity. The use of this technique is discussed briefly and data obtained in several fluids is presented.

  5. Low Viscosity Lubricating Oils with Superior Cold Properties,

    Science.gov (United States)

    The invention concerns low viscosity lubricating oils based on polyakylbenzenes. The patent claims the use of low boiling portions of the...distillation residues occurring in the alkylation of benzene with chloroparaffins or olefins of the C10 to C14 chain length, as low viscosity and low congealing lubricating oils or as congealing point lowering mix components.

  6. Elongational viscosity of narrow molar mass distribution polystyrene

    DEFF Research Database (Denmark)

    Bach, Anders; Almdal, Kristoffer; Rasmussen, Henrik Koblitz;

    2003-01-01

    Transient and steady elongational viscosity has been measured for two narrow molar mass distribution polystyrene melts of molar masses 200 000 and 390 000 by means of a filament stretching rheometer. Total Hencky strains of about five have been obtained. The transient elongational viscosity rises...

  7. Rotational and spin viscosities of water: Application to nanofluidics

    DEFF Research Database (Denmark)

    Hansen, Jesper Søndergaard; Bruus, Henrik; Todd, B.D.

    2010-01-01

    In this paper we evaluate the rotational viscosity and the two spin viscosities for liquid water using equilibrium molecular dynamics. Water is modeled via the flexible SPC/Fw model where the Coulomb interactions are calculated via the Wolf method which enables the long simulation times required...

  8. A Riemann problem with small viscosity and dispersion

    Directory of Open Access Journals (Sweden)

    Kayyunnapara Thomas Joseph

    2006-09-01

    Full Text Available In this paper we prove existence of global solutions to a hyperbolic system in elastodynamics, with small viscosity and dispersion terms and derive estimates uniform in the viscosity-dispersion parameters. By passing to the limit, we prove the existence of solution the Riemann problem for the hyperbolic system with arbitrary Riemann data.

  9. Post glacial rebounds measure the viscosity of the lithosphere

    CERN Document Server

    Garai, J

    2003-01-01

    The observed higher uplift rates before the end of deglaciation requires the existence of a low viscosity channel or layer. The uplifts observed after the end of deglaciation does not show any contribution from this low viscosity channel and a homogeneous viscosity model fits very well to the observed uplift. Most of the researchers therefore prefer the homogeneous model and suggest that the higher uplift rate before the end of deglaciation is the result of elastic contamination. It has been shown that the elastic deformation of the lithosphere is far too small to be responsible for the observed extra uplift; therefore, the homogeneous viscosity model should be discredited. The homogeneous viscosity of the postglacial period and the high uplift rate of the late glacial period can be explained with a model which has an upper layer determining the homogeneous viscosity and the layer below it which has a low viscosity. The contribution to the uplift of this low viscosity layer is indistinguishable from an instan...

  10. Viscosity over entropy ratio in a quark plasma

    Science.gov (United States)

    Czerski, P.; Alberico, W. M.; Chiacchiera, S.; DePace, A.; Hansen, H.; Molinari, A.; Nardi, M.

    2009-02-01

    The quark viscosity in the quark-gluon plasma is evaluated in the hard thermal loop (HTL) approximation. The different contributions to the viscosity arising from the various components of the quark spectral function are discussed. The calculation is extended to finite values of the chemical potential.

  11. Note: precision viscosity measurement using suspended microchannel resonators.

    Science.gov (United States)

    Lee, I; Park, K; Lee, J

    2012-11-01

    We report the characterization of a suspended microchannel resonator (SMR) for viscosity measurements in a low viscosity regime (<10 mPa s) using two measurement schemes. First, the quality factor (Q-factor) of the SMR was characterized with glycerol-water mixtures. The measured Q-factor at 20 °C exhibits a bilinear behavior with the sensitivity of 1281 (mPa s)(-1) for a lower (1-4 mPa s) and 355 (mPa s)(-1) for a higher viscosity range (4-8 mPa s), respectively. The second scheme is the vibration amplitude monitoring of the SMR running in a closed loop feedback. When compared in terms of the measurement time, the amplitude-based measurement takes only 0.1 ~ 1 ms while the Q-factor-based measurement takes ~30 s. However, the viscosity resolution of the Q-factor-based measurement is at least three times better than the amplitude-based measurement. By comparing the Q-factors of heavy water and 9.65 wt.% glycerol-water mixture that have very similar viscosities but different densities, we confirmed that the SMR can measure the dynamic viscosity without the density correction. The obtained results demonstrate that the SMR can measure the fluid viscosity with high precision and even real-time monitoring of the viscosity change is possible with the amplitude-based measurement scheme.

  12. Viscosity and electrical resistivity of Al-Li melts

    Science.gov (United States)

    Kononenko, V. I.; Razhabov, A. A.; Ryabina, A. V.

    2011-08-01

    The kinematic viscosity and electrical resistivity of Al-Li alloys in the liquid state are studied by a combined electrodeless method. Some theoretical calculations performed to determine the viscosity and electrical resistance by comparing the calculated and experimental data are estimated.

  13. On-line measurement of food viscosity during flow

    DEFF Research Database (Denmark)

    Mason, Sarah Louise; Friis, Alan

    2006-01-01

    Sarah L. Mason and Alan Friis discuss some of the principles and equipment used to monitor food viscosity in real time.......Sarah L. Mason and Alan Friis discuss some of the principles and equipment used to monitor food viscosity in real time....

  14. Effect of viscosity on appetite and gastro-intestinal hormones

    NARCIS (Netherlands)

    Zijlstra, N.; Mars, M.; Wijk, de R.A.; Westerterp-Plantenga, M.S.; Holst, J.J.; Graaf, de C.

    2009-01-01

    In previous studies we showed that higher viscosity resulted in lower ad libitum intake and that eating rate is an important factor. In this study we aimed to explore the effect of viscosity on the gastro-intestinal hormones ghrelin, CCK-8 and GLP-1. Thirty-two subjects (22 ± 2 y, BMI 21.9 ± 2.2 kg/

  15. Viscosity Prediction of Hydrocarbon Mixtures Based on the Friction Theory

    DEFF Research Database (Denmark)

    Zeberg-Mikkelsen, Claus Kjær; Cisneros, Sergio; Stenby, Erling Halfdan

    2001-01-01

    The application and capability of the friction theory (f-theory) for viscosity predictions of hydrocarbon fluids is further illustrated by predicting the viscosity of binary and ternary liquid mixtures composed of n-alkanes ranging from n-pentane to n-decane for wide ranges of temperature and fro...

  16. Elongational viscosity of monodisperse and bidisperse polystyrene melts

    DEFF Research Database (Denmark)

    Nielsen, Jens Kromann; Rasmussen, Henrik K.; Hassager, Ole

    2006-01-01

    The start-up and steady uniaxial elongational viscosity have been measured for two monodisperse polystyrene melts with molecular weights of 52 and 103 kg/mole, and for three bidisperse polystyrene melts. The monodisperse melts show a maximum in the steady elongational viscosity vs. the elongation...

  17. The shear viscosity of gauge theory plasma with chemical potentials

    CERN Document Server

    Benincasa, P; Naryshkin, R; Benincasa, Paolo; Buchel, Alex; Naryshkin, Roman

    2007-01-01

    We consider strongly coupled gauge theory plasma with conserved global charges that allow for a dual gravitational description. We study the shear viscosity of the gauge theory plasma in the presence of chemical potentials for these charges. Using gauge theory/string theory correspondence we prove that at large 't Hooft coupling the ratio of the shear viscosity to the entropy density is universal.

  18. The shear viscosity of gauge theory plasma with chemical potentials

    Science.gov (United States)

    Benincasa, Paolo; Buchel, Alex; Naryshkin, Roman

    2007-02-01

    We consider strongly coupled gauge theory plasma with conserved global charges that allow for a dual gravitational description. We study the shear viscosity of the gauge theory plasma in the presence of chemical potentials for these charges. Using gauge theory/string theory correspondence we prove that at large 't Hooft coupling the ratio of the shear viscosity to the entropy density is universal.

  19. Nonlinear Eddy Viscosity Models applied to Wind Turbine Wakes

    DEFF Research Database (Denmark)

    Laan, van der, Paul Maarten; Sørensen, Niels N.; Réthoré, Pierre-Elouan;

    2013-01-01

    The linear k−ε eddy viscosity model and modified versions of two existing nonlinear eddy viscosity models are applied to single wind turbine wake simulations using a Reynolds Averaged Navier-Stokes code. Results are compared with field wake measurements. The nonlinear models give better results...

  20. Viscosity and compressibility of diacylglycerol under high pressure

    Science.gov (United States)

    Malanowski, Aleksander; Rostocki, A. J.; Kiełczyński, P.; Szalewski, M.; Balcerzak, A.; Kościesza, R.; Tarakowski, R.; Ptasznik, S.; Siegoczyński, R. M.

    2013-03-01

    The influence of high pressure on viscosity and compressibility of diacylglycerol (DAG) oil has been presented in this paper. The investigated DAG oil was composed of 82% of DAGs and 18% TAGs (triacylglycerols). The dynamic viscosity of DAG was investigated as a function of the pressure up to 400 MPa. The viscosity was measured by means of the surface acoustic wave method, where the acoustic waveguides were used as sensing elements. As the pressure was rising, the larger ultrasonic wave attenuation was observed, whereas amplitude decreased with the liquid viscosity augmentation. Measured changes of physical properties were most significant in the pressure range near the phase transition. Deeper understanding of DAG viscosity and compressibility changes versus pressure could shed more light on thermodynamic properties of edible oils.

  1. Effect of Fluid Viscosity on Centrifugal Pump Performance

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Nohhyeong [GS Caltex Corporation, Daejeon (Korea, Republic of)

    2013-06-15

    The characteristics of centrifugal pump performance according to fluid viscosity change were studied experimentally. A small volute pump with low specific speed was tested by changing the viscosity of an aqueous solution of sugar and glycerin, which is considered a Newtonian fluid. After finishing the test, the total head, shaft horsepower, and pump efficiency were compared with those of a water pump. The results are summarized as follows: when the fluid viscosity is increased, the shut-off head shows very little change but the total head decreases gradually as the flow increases, and this makes the H-Q curve leaning rapidly, and when the fluid viscosity is increased, the shaft horsepower shows very little change at the shutoff condition; however, the shaft horsepower increases more rapidly with an increase in the flow and viscosity.

  2. Bulk viscosity, interaction and the viability of phantom solutions

    CERN Document Server

    Leyva, Yoelsy

    2016-01-01

    We study the dynamics of a bulk viscosity model in the Eckart approach for a spatially flat Friedmann-Robertson-Walker (FRW) universe. We have included radiation and dark energy, assumed as perfect fluids, and dark matter treated as an imperfect fluid having bulk viscosity. We also introduce an interaction term between the dark matter and dark energy components. Considering that the bulk viscosity is proportional to the dark matter energy density and imposing a complete cosmological dynamics, we find bounds on the bulk viscosity in order to reproduce a matter-dominated era (MDE). This constraint is independent of the interaction term. Some late time phantom solutions are mathematically possible. However, the constraint imposed by a MDE restricts the interaction parameter, in the phantom solutions, to a region consistent with a null value, eliminating the possibility of late time stable solutions with $w<-1$. From the different cases that we study, the only possible scenario, with bulk viscosity and interac...

  3. Development of high viscosity coatings for advanced Space Shuttle applications

    Science.gov (United States)

    Garofalini, S. H.; Banas, R.; Creedon, J.

    1979-01-01

    Laboratory studies for increasing the thermal resistance of high viscosity coatings for silica reusable surface insulation are presented. The coatings are intended for the reentry temperature associated with advanced Space Shuttle applications which will involve aerodynamic shear forces during entry from earth orbits. Coating viscosity was increased by (1) reduction in the concentration of the low viscosity additive B2O3; (2) reduction in the particle size of the constituent powders in coatings; and (3) addition of a high viscosity glass former (GeO2). A coating system was produced by combining the three methods which showed apparent higher viscosity than the current coating, while satisfying all the current Shuttle Orbiter coating requirements.

  4. Bulk viscosity of spin-one color superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Sa' d, Basil A.

    2009-08-27

    The bulk viscosity of several quark matter phases is calculated. It is found that the effect of color superconductivity is not trivial, it may suppress, or enhance the bulk viscosity depending on the critical temperature and the temperature at which the bulk viscosity is calculated. Also, is it found that the effect of neutrino-emitting Urca processes cannot be neglected in the consideration of the bulk viscosity of strange quark matter. The results for the bulk viscosity of strange quark matter are used to calculate the r-mode instability window of quark stars with several possible phases. It is shown that each possible phase has a different structure for the r-mode instability window. (orig.)

  5. Viscosity and density dependence during maximal flow in man.

    Science.gov (United States)

    Staats, B A; Wilson, T A; Lai-Fook, S J; Rodarte, J R; Hyatt, R E

    1980-02-01

    Maximal expiratory flow curves were obtained from ten healthy subjects white breathing air and three other gas mixtures with different densities and viscosities. From these data, the magnitudes of the dependence of maximal flow on gas density and viscosity were obtained. The scaling laws of fluid mechanics, together with a model for the flow-limiting mechanism, were used to obtain a prediction of the relationship between the density dependence and the viscosity dependence of maximal flow. Although the data for individual subjects were too variable to allow a precise comparison with this prediction, the relationship between the mean density dependence and the mean viscosity dependence of all usbjects agreed with the theoretic prediction. This agreement supports the assumption, which is frequently made, that flow resistance rather than tissue visoelasticity is the dominant contributor to peripheral resistance. Information on the relationships between the pressure drop to the flow-limiting segment and flow, gas density and viscosity, and lung volume were also obtained.

  6. Measuring Solution Viscosity and its Effect on Enzyme Activity

    Directory of Open Access Journals (Sweden)

    Uribe Salvador

    2003-01-01

    Full Text Available In proteins, some processes require conformational changes involving structural domain diffusion. Among these processes are protein folding, unfolding and enzyme catalysis. During catalysis some enzymes undergo large conformational changes as they progress through the catalytic cycle. According to Kramers theory, solvent viscosity results in friction against proteins in solution, and this should result in decreased motion, inhibiting catalysis in motile enzymes. Solution viscosity was increased by adding increasing concentrations of glycerol, sucrose and trehalose, resulting in a decrease in the reaction rate of the H+-ATPase from the plasma membrane of Kluyveromyces lactis. A direct correlation was found between viscosity (&eegr; and the inhibition of the maximum rate of catalysis (V max. The protocol used to measure viscosity by means of a falling ball type viscometer is described, together with the determination of enzyme kinetics and the application of Kramers’ equation to evaluate the effect of viscosity on the rate of ATP hydrolysis by the H+-ATPase.

  7. Viscosity prescription for gravitationally unstable accretion disks

    CERN Document Server

    Rafikov, Roman R

    2015-01-01

    Gravitationally unstable accretion disks emerge in a variety of astrophysical contexts - giant planet formation, FU Orioni outbursts, feeding of AGNs, and the origin of Pop III stars. When a gravitationally unstable disk is unable to cool rapidly it settles into a quasi-stationary, fluctuating gravitoturbulent state, in which its Toomre Q remains close to a constant value Q_0~1. Here we develop an analytical formalism describing the evolution of such a disk, which is based on the assumptions of Q=Q_0 and local thermal equilibrium. Our approach works in the presence of additional sources of angular momentum transport (e.g. MRI), as well as external irradiation. Thermal balance dictates a unique value of the gravitoturbulent stress \\alpha_{gt} driving disk evolution, which is a function of the local surface density and angular frequency. We compare this approach with other commonly used gravitoturbulent viscosity prescriptions, which specify the explicit dependence of stress \\alpha_{gt} on Toomre Q in an ad hoc...

  8. Effects of Metal Ions on Viscosity of Aqueous Sodium Carboxylmethylcellulose Solution and Development of Dropping Ball Method on Viscosity

    Science.gov (United States)

    Set, Seng; Ford, David; Kita, Masakazu

    2015-01-01

    This research revealed that metal ions with different charges could significantly affect the viscosity of aqueous sodium carboxylmethylcellulose (CMC) solution. On the basis of an Ostwald viscometer, an improvised apparatus using a dropping ball for examining the viscosity of liquids/solutions has been developed. The results indicate that the…

  9. The viscosity of planetary tholeiitic melts: A configurational entropy model

    Science.gov (United States)

    Sehlke, Alexander; Whittington, Alan G.

    2016-10-01

    The viscosity (η) of silicate melts is a fundamental physical property controlling mass transfer in magmatic systems. Viscosity can span many orders of magnitude, strongly depending on temperature and composition. Several models are available that describe this dependency for terrestrial melts quite well. Planetary basaltic lavas however are distinctly different in composition, being dominantly alkali-poor, iron-rich and/or highly magnesian. We measured the viscosity of 20 anhydrous tholeiitic melts, of which 15 represent known or estimated surface compositions of Mars, Mercury, the Moon, Io and Vesta, by concentric cylinder and parallel plate viscometry. The planetary basalts span a viscosity range of 2 orders of magnitude at liquidus temperatures and 4 orders of magnitude near the glass transition, and can be more or less viscous than terrestrial lavas. We find that current models under- and overestimate superliquidus viscosities by up to 2 orders of magnitude for these compositions, and deviate even more strongly from measured viscosities toward the glass transition. We used the Adam-Gibbs theory (A-G) to relate viscosity (η) to absolute temperature (T) and the configurational entropy of the system at that temperature (Sconf), which is in the form of log η =Ae +Be /TSconf . Heat capacities (CP) for glasses and liquids of our investigated compositions were calculated via available literature models. We show that the A-G theory is applicable to model the viscosity of individual complex tholeiitic melts containing 10 or more major oxides as well or better than the commonly used empirical equations. We successfully modeled the global viscosity data set using a constant Ae of -3.34 ± 0.22 log units and 12 adjustable sub-parameters, which capture the compositional and temperature dependence on melt viscosity. Seven sub-parameters account for the compositional dependence of Be and 5 for Sconf. Our model reproduces the 496 measured viscosity data points with a 1

  10. GodunovSPH with shear viscosity: implementation and tests

    Science.gov (United States)

    Cha, Seung-Hoon; Wood, Matt A.

    2016-05-01

    The acceleration and energy dissipation terms due to the shear viscosity have been implemented and tested in GodunovSPH. The double summation method has been employed to avoid the well-known numerical noise of the second derivative in particle based codes. The plane Couette flow with various initial and boundary conditions have been used as tests, and the numerical and analytical results show a good agreement. Not only the viscosity-only calculation, but the full hydrodynamics simulations have been performed, and they show expected results as well. The very low kinematic viscosity simulations show a turbulent pattern when the Reynolds number exceeds ˜102. The critical value of the Reynolds number at the transition point of the laminar and turbulent flows coincides with the previous works approximately. A smoothed dynamic viscosity has been suggested to describe the individual kinematic viscosity of particles. The infinitely extended Couette flow which has two layers of different viscosities has been simulated to check the smoothed dynamic viscosity, and the result agrees well with the analytic solution. In order to compare the standard smoothed particle hydrodynamics (SPH) and GodunovSPH, the two layers test has been performed again with a density contrast. GodunovSPH shows less dispersion than the standard SPH, but there is no significant difference in the results. The results of the viscous ring evolution has also been presented as well, and the numerical results agrees with the analytic solution.

  11. Viscosity of molten lithium, thorium and beryllium fluorides mixtures

    Science.gov (United States)

    Merzlyakov, Alexander V.; Ignatiev, Victor V.; Abalin, Sergei S.

    2011-12-01

    Considering development of Molten Salt Fast Reactor (MSFR) concept, following Molten Salt fluorides mixtures have been chosen as an object for viscosity studies in this work (in mol%): 78LiF-22ThF 4; 71LiF-27ThF 4-2BeF 2 and 75LiF-20ThF 4-5BeF 2. Additionally, the effect of the 3 mol% CeF 3 additives on viscosity of the molten 75LiF-20ThF 4-5BeF 2 (mol%) salt mixture has been investigated experimentally. The method of torsional oscillations of cylindrical crucible filled by molten fluorides mixture has been chosen for kinematic viscosity measurement at temperatures up to 800-850 °C. In temperature ranges, where melts behave as normal liquids, dependences on viscosity vs. temperature are received: ν = А exp [B/T(K)], where ν - kinematic viscosity, m 2/s; T - temperature, K. The kinematic viscosity Rout mean squares (RMS) estimated in the assumption about dispersion homoscedasticity is (0.04-0.12) × 10 -6 (m 2/s). Discrepancies left in the data of viscosity for molten mixtures of LiF, BeF 2 and ThF 4 received by different researchers need further investigations in this area to be continued.

  12. Blood smear

    Science.gov (United States)

    ... some red blood cells shaped like spheres ( hereditary spherocytosis ) Increased breakdown of RBCs Presence of RBCs with ... normal Red blood cells, elliptocytosis Red blood cells, spherocytosis Acute lymphocytic leukemia - photomicrograph Red blood cells, multiple ...

  13. Blood culture

    Science.gov (United States)

    Culture - blood ... A blood sample is needed . The site where blood will be drawn is first cleaned with an antiseptic such ... organism from the skin getting into (contaminating) the blood sample and causing a false-positive result (see ...

  14. Blood Thinners

    Science.gov (United States)

    If you have some kinds of heart or blood vessel disease, or if you have poor blood flow to your brain, your doctor may recommend that you take a blood thinner. Blood thinners reduce the risk of heart ...

  15. Blood transfusions

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000431.htm Blood transfusions To use the sharing features on this ... several sources of blood which are described below. Blood From the Public (Volunteer Blood Donation) The most ...

  16. Singularities and Entropy in Bulk Viscosity Dark Energy Model

    Institute of Scientific and Technical Information of China (English)

    孟新河; 窦旭

    2011-01-01

    In this paper bulk viscosity is introduced to describe the effects of cosmic non-perfect fluid on the cosmos evolution and to build the unified dark energy (DE) with (dark) matter models. Also we derive a general relation between the bulk viscosity form and Hubble parameter that can provide a procedure for the viscosity DE model building. Especially, a redshift dependent viscosity parameter ζ ∝ λ0 +λ1(1 +z)n proposed in the previous work [X.H. Meng and X. Dou, Commun. Theor. Phys. B2 (2009) 377] is investigated extensively in this present work. Further more we use the recently released supernova dataset (the Constitution dataset) to constrain the model parameters. In order to differentiate the proposed concrete dark energy models from the well known ACDM model, statefinder diagnostic method is applied to this bulk viscosity model, as a complementary to the Om parameter diagnostic and the deceleration parameter analysis performed by us before. The DE model evolution behavior and tendency are shown in the plane of the statefinder diagnostic parameter pair {τ, s} as axes where the fixed point represents the A CDM model The possible singularity property in this bulk viscosity cosmology is also discussed to which we can conclude that in the different parameter regions chosen properly, this concrete viscosity DE model can have various late evolution behaviors and the late time singularity could be avoided. We also calculate the cosmic entropy in the bulk viscosity dark energy frame, and find that the total entropy in the viscosity DE model increases monotonously with respect to the scale factor evolution, thus this monotonous increasing property can indicate an arrow of time in the universe evolution, though the quantum version of the arrow of time is still very puzzling.

  17. Shear viscosity of $\\beta$-stable nuclear matter

    CERN Document Server

    Benhar, Omar

    2009-01-01

    Viscosity plays a critical role in determining the stability of rotating neutron stars. We report the results of a calculation of the shear viscosity of $\\beta$~-~stable matter, carried out using an effective interaction based on a state-of-the-art nucleon-nucleon potential and the formalism of correlated basis functions. Within our approach the equation of state, determining the proton fraction, and the nucleon-nucleon scattering probability are consistently obtained from the same dynamical model. The results show that, while the neutron contribution to the viscosity is always dominant, above nuclear saturation density the electron contribution becomes appreciable.

  18. Nonlocal transport and the hydrodynamic shear viscosity in graphene

    Science.gov (United States)

    Torre, Iacopo; Tomadin, Andrea; Geim, Andre K.; Polini, Marco

    2015-10-01

    Motivated by recent experimental progress in preparing encapsulated graphene sheets with ultrahigh mobilities up to room temperature, we present a theoretical study of dc transport in doped graphene in the hydrodynamic regime. By using the continuity and Navier-Stokes equations, we demonstrate analytically that measurements of nonlocal resistances in multiterminal Hall bar devices can be used to extract the hydrodynamic shear viscosity of the two-dimensional (2D) electron liquid in graphene. We also discuss how to probe the viscosity-dominated hydrodynamic transport regime by scanning probe potentiometry and magnetometry. Our approach enables measurements of the viscosity of any 2D electron liquid in the hydrodynamic transport regime.

  19. Shear viscosities of photons in strongly coupled plasmas

    Science.gov (United States)

    Yang, Di-Lun; Müller, Berndt

    2016-09-01

    We investigate the shear viscosity of thermalized photons in the quark gluon plasma (QGP) at weak coupling and N = 4 super Yang-Mills plasma (SYMP) at both strong and weak couplings. We find that the shear viscosity due to the photon-parton scattering up to the leading order of electromagnetic coupling is suppressed when the coupling of the QGP/SYMP is increased, which stems from the blue-shift of the thermal-photon spectrum at strong coupling. In addition, the shear viscosity rapidly increases near the deconfinement transition in a phenomenological model analogous to the QGP.

  20. Shear viscosities of photons in strongly coupled plasmas

    Directory of Open Access Journals (Sweden)

    Di-Lun Yang

    2016-09-01

    Full Text Available We investigate the shear viscosity of thermalized photons in the quark gluon plasma (QGP at weak coupling and N=4 super Yang–Mills plasma (SYMP at both strong and weak couplings. We find that the shear viscosity due to the photon–parton scattering up to the leading order of electromagnetic coupling is suppressed when the coupling of the QGP/SYMP is increased, which stems from the blue-shift of the thermal-photon spectrum at strong coupling. In addition, the shear viscosity rapidly increases near the deconfinement transition in a phenomenological model analogous to the QGP.

  1. Unification of viscose models for powder suspension system

    Institute of Scientific and Technical Information of China (English)

    梁叔全; 李伟洲; 黄伯云

    2002-01-01

    The viscose models for powder suspension system was reviewed and analysed. It is found that by introducing modification function f(φ) in the differential form of classical Einsteins viscosity law, all of viscose models can be unified if f(φ) takes suitable form . Some rational forms of the function f(φ) were discussed according to functional approximation method, and a new rheological model contained two undetermined parameters was consequently developed, more suitable for high particle concentration dispersing system. The experimental results show that this new model is of better consistence.

  2. Numerical solutions of Williamson fluid with pressure dependent viscosity

    Science.gov (United States)

    Zehra, Iffat; Yousaf, Malik Muhammad; Nadeem, Sohail

    In the present paper, we have examined the flow of Williamson fluid in an inclined channel with pressure dependent viscosity. The governing equations of motion for Williamson fluid model under the effects of pressure dependent viscosity and pressure dependent porosity are modeled and then solved numerically by the shooting method with Runge Kutta Fehlberg for two types of geometries i.e., (i) Poiseuille flow and (ii) Couette flow. Four different cases for pressure dependent viscosity and pressure dependent porosity are assumed and the physical features of pertinent parameters are discussed through graphs.

  3. Numerical solutions of Williamson fluid with pressure dependent viscosity

    Directory of Open Access Journals (Sweden)

    Iffat Zehra

    2015-01-01

    Full Text Available In the present paper, we have examined the flow of Williamson fluid in an inclined channel with pressure dependent viscosity. The governing equations of motion for Williamson fluid model under the effects of pressure dependent viscosity and pressure dependent porosity are modeled and then solved numerically by the shooting method with Runge Kutta Fehlberg for two types of geometries i.e., (i Poiseuille flow and (ii Couette flow. Four different cases for pressure dependent viscosity and pressure dependent porosity are assumed and the physical features of pertinent parameters are discussed through graphs.

  4. Physical Parameters of Blood as a Non - Newtonian Fluid

    OpenAIRE

    Baieth, H. E. Abdel

    2008-01-01

    Do increasing doses of electromagnetic fields (EMFs) increase the hazards effect on blood? Studies on the blood of rats provide guidance for the assessment of occupational and public health significance of exposure to EMFs. Here, apparent additive viscosity of animal blood after exposing to EMFs (3,5 and 10 gauss) is examined. The results indicate that hematocrite (HCT) increased as EMF increases while the viscocity decreased with the increase of EMF. Red blood cell permeability, deformabilit...

  5. Rye affects bacterial translocation, intestinal viscosity, microbiota composition and bone mineralization in Turkey poults.

    Science.gov (United States)

    Tellez, Guillermo; Latorre, Juan D; Kuttappan, Vivek A; Hargis, Billy M; Hernandez-Velasco, Xochitl

    2015-01-01

    Previously, we have reported that rye significantly increased both viscosity and Clostridium perfringens proliferation when compared with corn in an in vitro digestive model. Two independent trials were conducted to evaluate the effect of rye as a source of energy on bacterial translocation, intestinal viscosity, gut microbiota composition, and bone mineralization, when compared with corn in turkey poults. In each experiment, day-of-hatch, turkey poults were randomly assigned to either a corn or a rye diet (n = 0 /group). At 10 d of age, in both experiments, 12 birds/group were given an oral gavage dose of fluorescein isothiocyanate dextran (FITC-d). After 2.5 h of oral gavage, blood and liver samples were collected to evaluate the passage of FITC-d and bacterial translocation (BT) respectively. Duodenum, ileum and cecum gut sections were collected to evaluate intestinal viscosity and to enumerate gut microbiota. Tibias were collected for observation of bone parameters. Broilers fed with a rye diet showed increased (pBacterial enumeration revealed that turkey poults fed with rye had increased the number of total lactic acid bacteria (LAB) in all three sections of the gastrointestinal tract evaluated when compared to turkey poults fed with corn. Turkey poults fed with rye also had significantly higher coliforms in duodenum and ileum but not in the ceca, whereas the total number of anaerobes increased only in duodenum. A significant reduction in bone strength and bone mineralization was observed in turkey poults fed with rye when compared with corn fed turkey poults. In conclusion, rye evoked mucosal damage in turkey poults that increased intestinal viscosity, increased leakage through the intestinal tract, and altered the microbiota composition and bone mineralization. Studies to evaluate dietary inclusion of selected Direct-Fed Microbial (DFM) candidates that produce exogenous enzymes in rye fed turkey poults are currently being evaluated.

  6. Viscosity of aluminum under shock-loading conditions

    Institute of Scientific and Technical Information of China (English)

    Ma Xiao-Juan; Liu Fu-Sheng; Zhang Ming-Jian; Sun Yan-Yun

    2011-01-01

    A reliable data treatment method is critical for viscosity measurements using the disturbance amplitude damping method of shock waves. In this paper the finite difference method is used to obtain the numerical solutions for the disturbance amplitude damping behaviour of the sinusoidal shock front in a flyer-impact experiment. The disturbance amplitude damping curves are used to depict the numerical solutions of viscous flow. By fitting the experimental data to the numerical solutions of different viscosities, we find that the effective shear viscosity coefficients of shocked aluminum at pressures of 42, 78 and 101 GPa are (1500±100) Pa. s, (2800±100) Pa. s and (3500±100) Pa. s respectively. It is clear that the shear viscosity of aluminum increases with an increase in shock pressure, so aluminum does not melt below a shock pressure of 101 GPa. This conclusion is consistent with the sound velocity measurement.

  7. Modeling effective viscosity reduction behaviour of solid suspensions

    Institute of Scientific and Technical Information of China (English)

    Wei En-Bo; Ji Yan-Ju; Zhang Jun

    2012-01-01

    Under a simple shearing flow,the effective viscosity of solid suspensions can be reduced by controlling the inclusion particle size or the number of inclusion particles in a unit volume.Based on the Stokes equation,the transformation field method is used to model the reduction behaviour of effective viscosity of solid suspensions theoretically by enlarging the particle size at a given high concentration of particles.With a lot of samples of random cubic particles in a unit cell,our statistical results show that at the same higher concentration,the effective viscosity of solid suspensions can be reduced by increasing the particle size or reducing the number of inclusion particles in a unit volume.This work discloses the viscosity reduction mechanism of increasing particle size,which is observed experimentally.

  8. An accurate empirical correlation for predicting natural gas viscosity

    Institute of Scientific and Technical Information of China (English)

    Ehsan Sanjari; Ebrahim Nemati Lay; Mohammad Peymani

    2011-01-01

    Natural gas viscosity is an important parameter in many gas and petroleum engineering calculations.This study presents a new empirical model for quickly calculating the natural gas viscosity.The model was derived from 4089 experimental viscosity data with varieties ranging from 0.01to 21,and 1 to 3 of pseudo reduced pressure and temperature,respectively.The accuracy of this new empirical correlation has been compared with commonly used empirical models,including Lee et al.,Heidaryan et al.,Carr et al.,and Adel Elsharkawy correlations.The comparison indicates that this new empirical model can predict viscosity of natural gas with average absolute relative deviation percentage AARD (%) of 2.173.

  9. Packing and viscosity of concentrated polydisperse coal-water slurries

    Energy Technology Data Exchange (ETDEWEB)

    Veytsman, B.; Morrison, J.; Scaroni, A.; Painter, P. [Pennsylvania State University, University Park, PA (United States). Energy Inst.

    1998-09-01

    The viscosity of polydisperse slurries close to the packing limit is discussed. It is shown that the divergence of the viscosity at the close packing limit causes the dependence of the slurry viscosity on loading to be universal. Ways of increasing the maximal loading of polydisperse slurries are described. A new theory of packing of powders based on a generalization of the Furnas telescopic tube method is proposed. Unlike the original Furnas model, this theory allows the calculation of the maximal packing for powders with an arbitrary size distribution of particles. The application of the theory to the problem of reducing the viscosity of coal-water slurries is discussed. 15 refs., 8 figs.

  10. Viscosity and density tables of sodium chloride solutions

    Energy Technology Data Exchange (ETDEWEB)

    Fair, J.A.; Ozbek, H. (comps.)

    1977-04-01

    A file is presented containing tabulated data extracted from the scientific literature on the density and viscosity of aqueous sodium chloride solutions. Also included is a bibliography of the properties of aqueous sodium chloride solutions. (MHR)

  11. Peristalsis of nonconstant viscosity Jeffrey fluid with nanoparticles

    Science.gov (United States)

    Alvi, N.; Latif, T.; Hussain, Q.; Asghar, S.

    Mixed convective peristaltic activity of variable viscosity nanofluids is addressed. Unlike the conventional consideration of constant viscosity; the viscosity is taken as temperature dependent. Constitutive relations for linear viscoelastic Jeffrey fluid are employed and uniform magnetic field is applied in the transverse direction. For nanofluids, the formulation is completed in presence of Brownian motion, thermophoresis, viscous dissipation and Joule heating. Consideration of temperature dependence of viscosity is not a choice but the realistic requirement of the wall temperature and the heat generated due to the viscous dissipation. Well established large wavelength and small Reynolds number approximations are invoked. Non-linear coupled system is analytically solved for the convergent series solutions identifying the interval of convergence explicitly. A comparative study between analytical and numerical solution is made for certainty. Influence of the parameters undertaken for the description of the problem is pointed out and its physics explained.

  12. Viscosity Measurements and Correlation of the Squalane + CO2 Mixture

    Science.gov (United States)

    Tomida, D.; Kumagai, A.; Yokoyama, C.

    2007-02-01

    Experimental results for the viscosity of squalane + CO2 mixtures are reported. The viscosities were measured using a rolling ball viscometer. The experimental temperatures were 293.15, 313.15, 333.15, and 353.15 K, and pressures were 10.0, 15.0, and 20.0 MPa. The CO2 mole fraction of the mixtures varied from 0 to 0.417. The experimental uncertainties in viscosity were estimated to be within ±3.0%. The viscosity of the mixtures decreased with an increase in the CO2 mole fraction. The experimental data were compared with predictions from the Grunberg-Nissan and McAllister equations, which correlated the experimental data with maximum deviations of 10 and 8.7%, respectively.

  13. Mechanism of sulfide effect on viscosity of HPAM polymer solution

    Institute of Scientific and Technical Information of China (English)

    康万利; 周阳; 王志伟; 孟令伟; 刘述忍; 白宝君

    2008-01-01

    The effect of sulfide on HPAM solution viscosity was studied using BROOKFIELD DV-II viscometer,and the interaction mechanism was discussed.The HPAM solution viscosity was investigated through fully reducing sulfide by the addition of hydrogen peroxide oxidation,and the mechanism of increasing polymer viscosity was investigated.The experimental results also show that there is a critical concentration of 15 mg/L.Below it,the loss rate of HPAM solution viscosity increases more rapidly,but becomes slowly above the critical concentration.A theoretical guidance for oilfields to prepare polymer solution using sewage-water by eliminating sulfide,and it is also importance to prepare polymer solution using sewage-water and save fresh water.

  14. Laboratory Procedures in Thermal Expansion and Viscosity of Liquids

    Science.gov (United States)

    Dawson, Paul Dow

    1974-01-01

    Describes the laboratory procedures for the measurement of thermal expansion and viscosity of liquids. These experiments require inexpensive equipment and are suitable for secondary school physical science classes. (JR)

  15. Viscosity and density of some lower alkyl chlorides and bromides

    Energy Technology Data Exchange (ETDEWEB)

    Rutherford, W.M.

    1988-07-01

    A high-pressure capillary viscometer, used previously to measure the viscosity of methyl chloride was rebuilt to eliminate the first-order dependence of the measured viscosity on the value assumed for the density of the fluid being investigated. At the same time, the system was arranged so that part of the apparatus could be used to measure density by a volumetric displacement technique. Viscosity and density were measured for ethyl chloride, 1-chloropropane, 1-chlorobutane, methyl bromide, ethyl bromide, and 1-bromopropane. The temperature and pressure ranges of the experiments were 20-150 /sup 0/C and 0.27-6.99 MPa, respectively. The accuracy of the viscosity measurements was estimated to be +-1% and of the density measurements, +-0.2%.

  16. Absolute viscosity measured using instrumented parallel plate system

    Science.gov (United States)

    Broyles, H. H.

    1967-01-01

    An automatic system measures the true average shear viscosity of liquids and viscoelastic materials, using the parallel plate method and automatically displays the results on a graphic record. This eliminates apparatus setup and extensive calculations.

  17. Compressibilities and viscosities of reference, vegetable, and synthetic gear lubricants

    DEFF Research Database (Denmark)

    Regueira Muñiz, Teresa; Lugo, Luis; Fernández, Josefa

    2014-01-01

    .06%. Dowson and Higginson and Zhu and Wen equations of state do not predict well the isothermal compressibilities, with AAD % being around 45% for both equations. Moreover, the viscosities were measured in the temperature range from 278.15 to 373.15 K at atmospheric pressure for these oils, and the viscosity...... index was also determined. New formulated oils present the highest viscosity indexes and the lowest viscosity data at low temperatures; therefore, they become the most suitable for machinery cold start. © 2014 American Chemical Society.......Nowadays, one of the primary choices of base oils for environmentally aware lubricants is vegetable oils. This is due to their good natural biodegradability and very low toxicity in combination with very good lubricity characteristics. The development of new vegetable-based lubricants requires...

  18. Seismic Constraints on the Mantle Viscosity Structure beneath Antarctica

    Science.gov (United States)

    Wiens, Douglas; Heeszel, David; Aster, Richard; Nyblade, Andrew; Wilson, Terry

    2015-04-01

    Lateral variations in upper mantle viscosity structure can have first order effects on glacial isostatic adjustment. These variations are expected to be particularly large for the Antarctic continent because of the stark geological contrast between ancient cratonic and recent tectonically active terrains in East and West Antarctica, respectively. A large misfit between observed and predicted GPS rates for West Antarctica probably results in part from the use of a laterally uniform viscosity structure. Although not linked by a simple relationship, mantle seismic velocities can provide important constraints on mantle viscosity structure, as they are both largely controlled by temperature and water content. Recent higher resolution seismic models for the Antarctic mantle, derived from data acquired by new seismic stations deployed in the AGAP/GAMSEIS and ANET/POLENET projects, offer the opportunity to use the seismic velocity structure to place new constraints on the viscosity of the Antarctic upper mantle. We use an Antarctic shear wave velocity model derived from array analysis of Rayleigh wave phase velocities [Heeszel et al, in prep] and examine a variety of methodologies for relating seismic, thermal and rheological parameters to compute a suite of viscosity models for the Antarctic mantle. A wide variety of viscosity structures can be derived using various assumptions, but they share several robust common elements. There is a viscosity contrast of at least two orders of magnitude between East and West Antarctica at depths of 80-250 km, reflecting the boundary between cold cratonic lithosphere in East Antarctica and warm upper mantle in West Antarctica. The region beneath the Ellsworth-Whitmore Mtns and extending to the Pensacola Mtns. shows intermediate viscosity between the extremes of East and West Antarctica. There are also significant variations between different parts of West Antarctica, with the lowest viscosity occurring beneath the Marie Byrd Land (MBL

  19. Viscosity measurements of crystallizing andesite from Tungurahua volcano (Ecuador)

    Science.gov (United States)

    Cimarelli, Corrado; deBiasi, Lea; Hanson, Jonathan B.; Lavallée, Yan; Arzilli, Fabio; Dingwell, Donald B.

    2015-01-01

    Abstract Viscosity has been determined during isothermal crystallization of an andesite from Tungurahua volcano (Ecuador). Viscosity was continuously recorded using the concentric cylinder method and employing a Pt‐sheathed alumina spindle at 1 bar and from 1400°C to subliquidus temperatures to track rheological changes during crystallization. The disposable spindle was not extracted from the sample but rather left in the sample during quenching thus preserving an undisturbed textural configuration of the crystals. The inspection of products quenched during the crystallization process reveals evidence for heterogeneous crystal nucleation at the spindle and near the crucible wall, as well as crystal alignment in the flow field. At the end of the crystallization, defined when viscosity is constant, plagioclase is homogeneously distributed throughout the crucible (with the single exception of experiment performed at the lowest temperature). In this experiments, the crystallization kinetics appear to be strongly affected by the stirring conditions of the viscosity determinations. A TTT (Time‐Temperature‐Transformation) diagram illustrating the crystallization “nose” for this andesite under stirring conditions and at ambient pressure has been constructed. We further note that at a given crystal content and distribution, the high aspect ratio of the acicular plagioclase yields a shear‐thinning rheology at crystal contents as low as 13 vol %, and that the relative viscosity is higher than predicted from existing viscosity models. These viscosity experiments hold the potential for delivering insights into the relative influences of the cooling path, undercooling, and deformation on crystallization kinetics and resultant crystal morphologies, as well as their impact on magmatic viscosity. PMID:27656114

  20. Fatty acids, membrane viscosity, serotonin and ischemic heart disease

    OpenAIRE

    Cocchi Massimo; Tonello Lucio; Lercker Giovanni

    2010-01-01

    Abstract Novel markers for ischemic heart disease are under investigation by the scientific community at international level. This work focuses on a specific platelet membrane fatty acid condition of viscosity which is linked to molecular aspects such as serotonin and G proteins, factors involved in vascular biology. A suggestive hypothesis is considered about the possibility to use platelet membrane viscosity, in relation to serotonin or, indirectly, the fatty acid profile, as indicator of i...

  1. Intrinsic ambiguity in second order viscosity parameters in relativistic hydrodynamics

    CERN Document Server

    Nakayama, Yu

    2012-01-01

    We show that relativistic hydrodynamics in Minkowski space-time has intrinsic ambiguity in second order viscosity parameters in the Landau-Lifshitz frame. This stems from the possibility of improvements of energy-momentum tensor. There exist at least two viscosity parameters which can be removed by using this ambiguity in scale invariant hydrodynamics in (1+3) dimension, and seemingly non-conformal hydrodynamic theories can be hiddenly conformal invariant.

  2. Viscosity and mutual diffusion in strongly asymmetric binary ionic mixtures

    CERN Document Server

    Bastea, S

    2005-01-01

    We present molecular dynamics simulation results for the viscosity and mutual diffusion constant of a strongly asymmetric binary ionic mixture (BIM). We compare the results with available theoretical models previously tested for much smaller asymmetries. For the case of viscosity we propose a new predictive framework based on the linear mixing rule, while for mutual diffusion we discuss some consistency problems of widely used Boltzmann equation based models.

  3. Convergence of a residual based artificial viscosity finite element method

    KAUST Repository

    Nazarov, Murtazo

    2013-02-01

    We present a residual based artificial viscosity finite element method to solve conservation laws. The Galerkin approximation is stabilized by only residual based artificial viscosity, without any least-squares, SUPG, or streamline diffusion terms. We prove convergence of the method, applied to a scalar conservation law in two space dimensions, toward an unique entropy solution for implicit time stepping schemes. © 2012 Elsevier B.V. All rights reserved.

  4. Chebyshev super spectral viscosity method for a fluidized bed model

    CERN Document Server

    Sarra, S A

    2003-01-01

    A Chebyshev super spectral viscosity method and operator splitting are used to solve a hyperbolic system of conservation laws with a source term modeling a fluidized bed. The fluidized bed displays a slugging behavior which corresponds to shocks in the solution. A modified Gegenbauer postprocessing procedure is used to obtain a solution which is free of oscillations caused by the Gibbs-Wilbraham phenomenon in the spectral viscosity solution. Conservation is maintained by working with unphysical negative particle concentrations.

  5. Entropy production, viscosity bounds and bumpy black holes

    OpenAIRE

    Hartnoll, Sean; Ramirez, David; Santos, Jorge

    2016-01-01

    The ratio of shear viscosity to entropy density, $\\eta/s$, is computed in various holographic geometries that break translation invariance (but are isotropic). The shear viscosity does not have a hydrodynamic interpretation in such backgrounds, but does quantify the rate of entropy production due to a strain. Fluctuations of the metric components $\\delta g_{xy}$ are massive about these backgrounds, leading to $\\eta/s < 1/(4\\pi)$ at all finite temperatures (even in Einstein gravity). As the te...

  6. The shear viscosity of gauge theory plasma with chemical potentials

    Energy Technology Data Exchange (ETDEWEB)

    Benincasa, Paolo [Department of Applied Mathematics, University of Western Ontario, London, Ontario N6A 5B7 (Canada); Buchel, Alex [Department of Applied Mathematics, University of Western Ontario, London, Ontario N6A 5B7 (Canada) and Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2J 2W9 (Canada)]. E-mail: abuchel@perimeterinstitute.ca; Naryshkin, Roman [Department of Applied Mathematics, University of Western Ontario, London, Ontario N6A 5B7 (Canada); Physics Department, Taras Shevchenko Kiev National University, Prosp. Glushkova 6, Kiev 03022 (Ukraine)

    2007-02-08

    We consider strongly coupled gauge theory plasma with conserved global charges that allow for a dual gravitational description. We study the shear viscosity of the gauge theory plasma in the presence of chemical potentials for these charges. Using gauge theory/string theory correspondence we prove that at large 't Hooft coupling the ratio of the shear viscosity to the entropy density is universal.

  7. Viscosity measurements of crystallizing andesite from Tungurahua volcano (Ecuador).

    Science.gov (United States)

    Chevrel, Magdalena Oryaëlle; Cimarelli, Corrado; deBiasi, Lea; Hanson, Jonathan B; Lavallée, Yan; Arzilli, Fabio; Dingwell, Donald B

    2015-03-01

    Viscosity has been determined during isothermal crystallization of an andesite from Tungurahua volcano (Ecuador). Viscosity was continuously recorded using the concentric cylinder method and employing a Pt-sheathed alumina spindle at 1 bar and from 1400°C to subliquidus temperatures to track rheological changes during crystallization. The disposable spindle was not extracted from the sample but rather left in the sample during quenching thus preserving an undisturbed textural configuration of the crystals. The inspection of products quenched during the crystallization process reveals evidence for heterogeneous crystal nucleation at the spindle and near the crucible wall, as well as crystal alignment in the flow field. At the end of the crystallization, defined when viscosity is constant, plagioclase is homogeneously distributed throughout the crucible (with the single exception of experiment performed at the lowest temperature). In this experiments, the crystallization kinetics appear to be strongly affected by the stirring conditions of the viscosity determinations. A TTT (Time-Temperature-Transformation) diagram illustrating the crystallization "nose" for this andesite under stirring conditions and at ambient pressure has been constructed. We further note that at a given crystal content and distribution, the high aspect ratio of the acicular plagioclase yields a shear-thinning rheology at crystal contents as low as 13 vol %, and that the relative viscosity is higher than predicted from existing viscosity models. These viscosity experiments hold the potential for delivering insights into the relative influences of the cooling path, undercooling, and deformation on crystallization kinetics and resultant crystal morphologies, as well as their impact on magmatic viscosity.

  8. Viscosity and mutual diffusion in strongly asymmetric plasma mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Bastea, S

    2004-09-07

    The authors present molecular dynamics simulation results for the viscosity and mutual diffusion constant of a strongly asymmetric two-component plasma (TCP). They compare the results with available theoretical models previously tested for much smaller asymmetries. for the case of viscosity they propose a new predictive framework based on the linear mixing rule, while for mutual diffusion they point out some consistency problems of widely used Boltzmann equation based models.

  9. Effect of viscosity on harmonic signals from magnetic fluid

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Takashi, E-mail: t_yoshi@ees.kyushu-u.ac.jp; Bai, Shi; Hirokawa, Aiki; Tanabe, Kazuhiro; Enpuku, Keiji

    2015-04-15

    We explored the effect of viscosity on harmonic signals from a magnetic fluid. Using a numerical simulation that accounts for both the Brownian and Néel processes, we clarified how the magnetization mechanism is affected by viscosity. When the excitation field varies much slower than the Brownian relaxation time, magnetization can be described by the Langevin function. On the other hand, for the case when the excitation field varies much faster than the Brownian relaxation time, but much slower than the Néel relaxation time, the easy axes of the magnetic nanoparticles (MNPs) turn to some extent toward the direction of the excitation field in an equilibrium state. This alignment of the easy axes of MNPs caused by the AC field becomes more significant with the increase of the AC field strength. Consequently, the magnetization is different from the Langevin function even though Néel relaxation time is faster than time period of the external frequency. It is necessary to consider these results when we use harmonic signals from a magnetic fluid in a high-viscosity medium. - Highlights: • We explore the effect of viscosity on harmonic signals from a magnetic fluid. • We clarify how the magnetization mechanism is affected by the viscosity of the fluid. • The magnetization in a high-viscosity medium is different from a Langevin function. • We empirically express the alignment of easy axes of the MNPs caused by an AC field.

  10. Effect of Solvation Film on the Viscosity of Colloidal Dispersions

    Institute of Scientific and Technical Information of China (English)

    PENG Chang-Sheng; GU Qing-Bao; SONG Shao-Xian

    2005-01-01

    Viscosity is one of the most important properties of colloids in mixing, transportation, stabilization, energy consumption, and so on. According to Einstein's viscosity equation, the viscosity of a colloidal dispersion increases with the increase of particle concentration. And the equation can be applicable to all micro-particle dispersions, because the effect of solvation films coated on particles can be neglectable in that case. But with the decrease of particle size to nano-scale, the formation of solvation films on nano-particles can greatly affect the viscosity of a dispersion, and Einstein's equation may not be applicable to this case. In this work, one kind of micro-size silica particle and two kinds of nano-size silica particles were used to investigate the effect of solvation films on dispersion viscosity, dispersed in water and ethyl alcohol solvents, respectively. The results of theoretical calculation and experimental investigation show that the increase of viscosity is contributed from solvation films by more than 95 percent for nano-particle dispersions, while less than 10 percent for micro-particle dispersions.

  11. ESTIMATION OF VISCOSITY ENGINE OILS USING ROTATIONAL RHEOMETER

    Directory of Open Access Journals (Sweden)

    Anna M. RYNIEWICZ

    2014-06-01

    Full Text Available The operating criteria, the assurance of energy-efficiency and environmental protection impose very diversified rheological requirements on the parameters of work of car engine oils. The aim of the work was the estimation of rheological parameters of selected car engine oils at controlled shear stress in a wide range of temperatures, using a rotational rheometer. Investigated mineral engine oils, semi-synthetic and synthetic ones that belong to different viscosity classes. The characteristics of viscosity in relation to temperature in the testing node were determined. The results of tests at sub-zero and low temperatures indicate significant differentiation of rheological properties of engine oils. It can be claimed that in the exploited friction nodes, especially in the conditions of fluid and mixed friction, the smallest viscosity is characteristic to the fully synthetic oils from the tested group 5W and the semi-synthetic oil Orlen Gas Semisynthetic 10W-40. Semi-synthetic oil Platinum Rally Sport 10W-60 stands out as its viscosity values at sub-zero and low temperatures are greater than the ones of mineral oils from the tested group 15W-40. At high temperatures one can distinguish the oil called Elf Sporti SRI 15W-40 whose viscosity very slightly decreases. The conducted oil tests confirmed their catalog parameters and affiliation to viscosity classes.

  12. Viscosity of In and In-Sb alloys

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The dynamic viscosity of pure In, In-1%Sb (mass fraction, so as the follows) alloy, In-55%Sb hypoeutectic alloyand In-69.5%Sb eutectic alloy was measured by using a torsional oscillation viscometer at different temperatures above liq-uidus. The experimental results show that the viscosity of these melts decreases with increasing temperature. The anomalouschange of viscosity occurs at about 430 and 470℃ in pure In melt. The variation of viscosity with temperature well meetsexponential correlation and no anomalous change occurs in measured temperature range in the In-1%Sb alloy melt. A tran-sition occurs at about 800℃ in both of In-55%Sb and In-69.5%Sb alloy melts. The sudden change of viscosity suggests thestructure change of melts. DSC (differential scanning calorimetry) curves of In-1%Sb alloy during heating and cooling weremeasured, and the results show that no structural variation in In-1%Sb alloy melt was testified further. In addition, the vis-cosity of In melt decreases with the addition of 1%Sb.

  13. Ras diffusion is sensitive to plasma membrane viscosity.

    Science.gov (United States)

    Goodwin, J Shawn; Drake, Kimberly R; Remmert, Catha L; Kenworthy, Anne K

    2005-08-01

    The cell surface contains a variety of barriers and obstacles that slow the lateral diffusion of glycosylphosphatidylinositol (GPI)-anchored and transmembrane proteins below the theoretical limit imposed by membrane viscosity. How the diffusion of proteins residing exclusively on the inner leaflet of the plasma membrane is regulated has been largely unexplored. We show here that the diffusion of the small GTPase Ras is sensitive to the viscosity of the plasma membrane. Using confocal fluorescence recovery after photobleaching, we examined the diffusion of green fluorescent protein (GFP)-tagged HRas, NRas, and KRas in COS-7 cells loaded with or depleted of cholesterol, a well-known modulator of membrane bilayer viscosity. In cells loaded with excess cholesterol, the diffusional mobilities of GFP-HRas, GFP-NRas, and GFP-KRas were significantly reduced, paralleling the behavior of the viscosity-sensitive lipid probes DiIC(16) and DiIC(18). However, the effects of cholesterol depletion on protein and lipid diffusion in cell membranes were highly dependent on the depletion method used. Cholesterol depletion with methyl-beta-cyclodextrin slowed Ras diffusion by a viscosity-independent mechanism, whereas overnight cholesterol depletion slightly increased both protein and lipid diffusion. The ability of Ras to sense membrane viscosity may represent a general feature of proteins residing on the cytoplasmic face of the plasma membrane.

  14. Reference Correlation for the Viscosity of Carbon Dioxide

    Science.gov (United States)

    Laesecke, Arno; Muzny, Chris D.

    2017-03-01

    A comprehensive database of experimental and computed data for the viscosity of carbon dioxide (CO2) was compiled and a new reference correlation was developed. Literature results based on an ab initio potential energy surface were the foundation of the correlation of the viscosity in the limit of zero density in the temperature range from 100 to 2000 K. Guided symbolic regression was employed to obtain a new functional form that extrapolates correctly to 0 and to 10 000 K. Coordinated measurements at low density made it possible to implement the temperature dependence of the Rainwater-Friend theory in the linear-in-density viscosity term. The residual viscosity could be formulated with a scaling term ργ/T, the significance of which was confirmed by symbolic regression. The final viscosity correlation covers temperatures from 100 to 2000 K for gaseous CO2 and from 220 to 700 K with pressures along the melting line up to 8000 MPa for compressed and supercritical liquid states. The data representation is more accurate than with the previous correlations, and the covered pressure and temperature range is significantly extended. The critical enhancement of the viscosity of CO2 is included in the new correlation.

  15. Viscosity of gruels for infants: a comparison of measurement procedures.

    Science.gov (United States)

    Mouquet, C; Trèche, S

    2001-09-01

    Numerous studies have been carried out to investigate energy density and consistency of gruels for infants in developing countries. However, starch-rich gruels have a complex rheological behavior and their consistency is difficult to characterize. Many published gruel viscosity data are available, but the lack of standardized viscosity measurement procedures makes comparisons and interpretations difficult. The influences of viscometer type and viscosity measurement conditions on gruels prepared with simple or multicomponent flours were assessed in this study. The results showed a drastic decrease in apparent viscosity when the shear rate increased. Other factors like shear time and gruel temperature also had a marked influence on apparent viscosity. For two types of gruel (maize or multicomponent flour) prepared at different concentrations, correspondences between a short qualitative description of the consistency and apparent viscosity values obtained with several viscometers in different measurement conditions are given. Finally, recommendations are put forward on techniques to obtain valid data on gruel consistency, adapted to each type of study (laboratory, field or large-scale surveys).

  16. Development of Viscosity Model for Petroleum Industry Applications

    Science.gov (United States)

    Motahhari, Hamed reza

    Heavy oil and bitumen are challenging to produce and process due to their very high viscosity, but their viscosity can be reduced either by heating or dilution with a solvent. Given the key role of viscosity, an accurate viscosity model suitable for use with reservoir and process simulators is essential. While there are several viscosity models for natural gases and conventional oils, a compositional model applicable to heavy petroleum and diluents is lacking. The objective of this thesis is to develop a general compositional viscosity model that is applicable to natural gas mixtures, conventional crudes oils, heavy petroleum fluids, and their mixtures with solvents and other crudes. The recently developed Expanded Fluid (EF) viscosity correlation was selected as a suitable compositional viscosity model for petroleum applications. The correlation relates the viscosity of the fluid to its density over a broad range of pressures and temperatures. The other inputs are pressure and the dilute gas viscosity. Each fluid is characterized for the correlation by a set of fluid-specific parameters which are tuned to fit data. First, the applicability of the EF correlation was extended to asymmetric mixtures and liquid mixtures containing dissolved gas components. A new set of mass-fraction based mixing rules was developed to calculate the fluid-specific parameters for mixtures. The EF correlation with the new set of mixing rules predicted the viscosity of over 100 mixtures of hydrocarbon compounds and carbon dioxide with overall average absolute relative deviations (AARD) of less than 10% either with measured densities or densities estimated by Advanced Peng-Robinson equation of state (APR EoS). To improve the viscosity predictions with APR EoS-estimated densities, general correlations were developed for non-zero viscosity binary interaction parameters. The EF correlation was extended to non-hydrocarbon compounds typically encountered in natural gas industry. It was

  17. Blood Donation

    Science.gov (United States)

    Tests and Procedures Blood donation By Mayo Clinic Staff Blood donation is a voluntary procedure. You agree to have blood drawn so that it can ... have a disease that requires blood components. Blood donation makes all of this possible. There are several ...

  18. Viscosity Relaxation in Molten HgZnTe

    Science.gov (United States)

    Baird, James K.

    2002-01-01

    Because of its narrow electronic band-gap, HgZnTe solid solutions have been proposed as effective detectors for infrared radiation. To produce the best single crystals of these materials for this application, knowledge of the phase diagram that governs the freezing of the liquid is essential. Besides the phase diagram, however, some information concerning the thermophysical properties of the melt, such as viscosity, density, specific heat, and enthalpy of mixing, can also be useful. Of these thermophysical properties, the viscosity is perhaps of the most interest scientifically. Measurements using the oscillating cup method have shown that the isothermal melt requires tens of hours of equilibration time before a steady value of the viscosity can be achieved. Over this equilibration time, which depends upon temperature, the viscosity can increase by as much as a factor of two before reaching a steady state. We suggest that this relaxation phenomenon may be due to a slight polymerization of Te atoms in the melt. To account for the time dependence of the viscosity in the HgZnTe melt, we propose that the liquid acts as a solvent that favors the formation of Te atom chains. We suggest that as the melt is cooled from a high temperature to the temperature for measurement of the viscosity, a free radical polymerization of Te atoms begins. To estimate this average molecular weight, we use a simple free radical polymerization mechanism, including a depolymerization step, to calculate the time dependence to the concentration of each Te polymer molecular weight fraction. From these molecular weight fractions, we compute the weight average molecular weight of the distribution. Using the semi-empirical relation between average molecular weight and viscosity, we obtain a formula for the time dependence of the viscosity of the melt. Upon examining this formula, we find that the viscosity achieves a steady value when a balance is achieved between the rate of formation of the chains

  19. Effects of Circuit Resistance Training with Crocus Sativus (Saffron Supplementation on Plasma Viscosity and Fibrinogen

    Directory of Open Access Journals (Sweden)

    Abbass Ghanbari–Niaki

    2015-07-01

    Full Text Available A limited number of studies has been carried out concerning the combined effects of resistance training and saffron supplementation on cardiovascular risk factors. The aim of this study was to assess the effects of circuit resistance training with Crocus sativus (saffron supplementation on plasma viscosity and fibrinogen. For this purpose, 44 healthy male subjects, based on individual characteristics and after homogenization, were divided into four groups, including water-training (WT n=11, petal sweat–training (PST n=10, bottom part of flower-training (BFT n=11, and upper part of flower-training (UFT n=12. Resistance training consisted of 12 stations (each station for 30 seconds with 40% of one repetition maximum for 2 weeks (5 sessions per week. Saffron in the amount of 500 mg was used twice daily, i.e. in the morning and immediately after exercise. Blood samples were taken before and 48 hours after the last exercise session and were analyzed for fibrinogen and plasma viscosity. Significant differences were observed between groups in plasma levels of fibrinogen (P=0.01. The post hoc test showed significant differences between the UFT and PST groups and the UFT and BFT groups (respectively, P=0.04 and P=0.014. In the post-test, plasma fibrinogen had significantly decreased in the WT (P=0.005, PWT (P=0.003, and UFT (P=0.001 groups compared with pre-test data (within group difference. Moreover, plasma viscosity was significantly changed among groups (F3, 37=3.52, P=0.024. The post hoc test showed significant differences between the UFT and WT groups (P=0.037. In post-test data, plasma viscosity had significantly decreased in the WT (P=0.015 and UFT (P<0.001 groups compared with pre-test data. The present results show that circuit resistance training with saffron supplements can reduce cardiovascular risk factors (fibrinogen and plasma viscosity.

  20. Donating Blood

    Science.gov (United States)

    ... can't get an infection or disease from giving blood. The needles and other equipment used are sterile ... part of blood (plasma) within 72 hours after giving blood. It generally takes about 4–8 weeks to ...

  1. The influence of magnetic fields on crude oils viscosity

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, Jose L.; Bombard, Antonio J. F. [Universidade Federal de Itajuba (UNIFEI), Itajuba, MG (Brazil). Instituto de Ciencias Exatas. Lab. de Reologia

    2009-07-01

    The crystallization of paraffin causes serious problems in the process of transportation of petroleum. This phenomenon increases the crude oil viscosity and implies an organic resin accumulation on pipeline wall, resulting in a reduced flux area or totally blocked pipes. One of the most challenging tasks for pipeline maintenance is solving this problem at low cost. Therefore, a method that inhibits the crystallization of paraffin and reduces the viscosity of crude oil could have many useful applications within the petroleum industry. Recent studies showed that magnetic fields reduce the Wax Appearance Temperature (WAT) and the viscosity of paraffin-based crude oil. For better understanding of this discovery, a series of tests was performed. This paper will show the influence of a DC magnetic field on rheological proprieties of three crude oils with different paraffin concentrations: a crude oil sample with 11 % p/p of paraffin concentration (sample 1); a crude oil sample with 6 % p/p of paraffin concentration (sample 2); a mixture of paraffin plus light crude oil with a total of 11 % p/p of paraffin concentration. These samples were placed in an electromagnet that generates a magnetic field of 1.3 Tesla. The samples' temperatures were conditioned around their Wax Appearance Temperature (WAT), and they were exposed to the field. As the viscosity of crude oil is very sensitive to the changes in temperature, it was ensured that the temperature has remained constant throughout the process. The sample 1 revealed a considerable reduction of viscosity: its original viscosity was 66 cP before magnetic field exposure, after that its viscosity was reduced to 39 cP. The other samples showed the same viscosity, before and after the magnetic field exposure. Since the samples 1 and 3 have the same paraffin concentrations, the viscosity reduction is not due only to the presence of paraffin; there must be other factors responsible for the interaction of sample 1 with the

  2. Bulk Viscosity and Cavitation in Boost-Invariant Hydrodynamic Expansion

    CERN Document Server

    Rajagopal, Krishna

    2009-01-01

    We solve second order relativistic hydrodynamics equations for a boost-invariant 1+1-dimensional expanding fluid with an equation of state taken from lattice calculations of the thermodynamics of strongly coupled quark-gluon plasma. We investigate the dependence of the energy density as a function of proper time on the values of the shear viscosity, the bulk viscosity, and second order coefficients, confirming that large changes in the values of the latter have negligible effects. Varying the shear viscosity between zero and a few times s/(4 pi), with s the entropy density, has significant effects, as expected based on other studies. Introducing a nonzero bulk viscosity also has significant effects. In fact, if the bulk viscosity peaks near the crossover temperature Tc to the degree indicated by recent lattice calculations in QCD without quarks, it can make the fluid cavitate -- falling apart into droplets. It is interesting to see a hydrodynamic calculation predicting its own breakdown, via cavitation, at th...

  3. Dynamic viscosity measurement in non-Newtonian graphite nanofluids.

    Science.gov (United States)

    Duan, Fei; Wong, Ting Foong; Crivoi, Alexandru

    2012-07-02

    : The effective dynamic viscosity was measured in the graphite water-based nanofluids. The shear thinning non-Newtonian behavior is observed in the measurement. On the basis of the best fitting of the experimental data, the viscosity at zero shear rate or at infinite shear rate is determined for each of the fluids. It is found that increases of the particle volume concentration and the holding time period of the nanofluids result in an enhancement of the effective dynamic viscosity. The maximum enhancement of the effective dynamic viscosity at infinite rate of shear is more than 24 times in the nanofluids held for 3 days with the volume concentration of 4% in comparison with the base fluid. A transmission electron microscope is applied to reveal the morphology of aggregated nanoparticles qualitatively. The large and irregular aggregation of the particles is found in the 3-day fluids in the drying samples. The Raman spectra are extended to characterize the D and G peaks of the graphite structure in the nanofluids. The increasing intensity of the D peak indicates the nanoparticle aggregation growing with the higher concentration and the longer holding time of the nanofluids. The experimental results suggest that the increase on effective dynamic viscosity of nanofluids is related to the graphite nanoparticle aggregation in the fluids.

  4. Dark goo: Bulk viscosity as an alternative to dark energy

    CERN Document Server

    Gagnon, Jean-Sebastien

    2011-01-01

    We present a simple (microscopic) model in which bulk viscosity plays a role in explaining the present acceleration of the universe. The effect of bulk viscosity on the Friedmann equations is to turn the pressure into an "effective" pressure containing the bulk viscosity. For a sufficiently large bulk viscosity, the effective pressure becomes negative and could mimic a dark energy equation of state. Our microscopic model includes self-interacting spin-zero particles (for which the bulk viscosity is known) that are added to the usual energy content of the universe. We study both background equations and linear perturbations in this model. We show that a dark energy behavior is obtained for reasonable values of the two parameters of the model (i.e. the mass and coupling of the spin-zero particles) and that linear perturbations are well-behaved. There is no apparent fine tuning involved. We also discuss the conditions under which hydrodynamics holds, in particular that the spin-zero particles must be in local eq...

  5. Viscosity changes in hyaluronic acid: Irradiation and rheological studies

    Energy Technology Data Exchange (ETDEWEB)

    Daar, Eman [Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)], E-mail: e.daar@surrey.ac.uk; King, L.; Nisbet, A. [Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Thorpe, R.B. [Fluids and Systems Centre, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Bradley, D.A. [Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)

    2010-04-15

    Hyaluronic acid (HA) is a significant component of the extracellular matrix (ECM), particular interest being shown herein in synovial fluid. The present study aims to investigate the degrading effects of X-ray radiation on HA at radiotherapy doses. Measurements of viscosity and shear stresses on HA solutions have been made at different shear rates using various types of viscometer for different concentrations in the range 0.01-1% w/v of HA. The HA has been subjected to doses of 6 MV photon radiation ranging from 0 to 20 Gy, the major emphasis being on doses below 5 Gy. It is found that there is a dose-dependent relationship between viscosity and shear rate, viscosity reducing with radiation dose, this being related to polymer scissions via the action of radiation-induced free radicals. The dependency appears to become weaker at higher concentrations, possibly due to the contribution to viscosity from polymer entanglement becoming dominant over that from mean molecular weight. Present results, for HA solutions in the concentration range 0.01% to 1% w/v, show reduced viscosity with dose over the range 0-4 Gy, the latter covering the dose regime of interest in fractionated radiotherapy. The work also shows agreement with previous Raman microspectrometry findings by others, the possible bond alterations being defined by comparison with available published data.

  6. Dynamic viscosity study of barley malt and chicory concentrates

    Directory of Open Access Journals (Sweden)

    G. O. Magomedov

    2016-01-01

    Full Text Available The purpose of research is to find optimal conditions for dispersing and subsequent dehydration of liquid food environments in the nozzle spray drying chamber through the study of dynamic changes in viscosity according to temperature, velocities gradients and dry residue content. The objects of study were roasted chicory and malt barley concentrates with dry residue content of 20, 40, 60 and 80%. Research of dynamic viscosity were carried out at the measuring complex based on the rotational viscometer Rheotest II, analog-to-digital converter, module Laurent and a personal computer with a unique software that allows to record in real time (not only on a tape recorder, but also in the form of graphic files the behavior of the viscosity characteristics of concentrates. Registration of changes of dynamic viscosity was carried out at a shear rate gradient from 1,0 с -1 to 27,0 с -1 and the products temperature thermostating : 35, 55, 75˚ C. The research results are presented in the form of graphic dependences of effective viscosity on shear rate and flow curves (dependencies of shear stresses on the velocity gradient, which defined flow regimes, the optimal modes of dispersion concentrates into spray dryer chambers in obtaining of powdered semi-finished products and instanting were found: dry residue content - 40 %, concentrate temperature - 75 ˚C, velocity gradient in the air channel of the nozzle at least 20 c-1

  7. Low viscosity automatic transmission fluids with enhanced friction durability

    Institute of Scientific and Technical Information of China (English)

    Kenji Yatsunami; Samuel H. Tersigni; TANG Hong- zhi; Lee D. Saathoff; Christopher S. Cleveland; Mark Jones

    2009-01-01

    This study focused on the development of a new low viscosity automatic transmission fluid (ATF) with enhanced friction durability to meet the needs of new step type automatic transmissions. Recent high fuel prices encourage increased efficiency in the driveline, including the transmission. Reduction in fluid viscosity and wider use of slip control in torque con-verter clutches are two ways to practically improve fuel efficiency. Increased torque and more shifting is seen with a variety of new transmission hardware platforms, such as wet starting clutches, dual clutches and seven - or eight - speed ATs.This suggests the need for enhanced levels of friction durability from the ATF. The new challenge from this hardware for the ATF formulator lies in the need to simultaneously meet the wear, friction durability and torque capacity requirements at low viscosity in a cost- effective manner. This report introduced a new low viscosity fluid that represents a different commercial ATF formulation style. The new chemistry employs a low viscosity for increased fuel economy, while easily doubling the friction durability of current conven-tional ATFs and offering higher torque and better EP.

  8. Investigation of viscosity of whole hydrolyze sweetened condensed milk

    Directory of Open Access Journals (Sweden)

    O. Kalinina

    2015-05-01

    Full Text Available Introduction. Рaper is aimed at developing of low-lactose (hydrolyzed sweetened condensed milk products technology for lactose intolerant people and for the whole population. Materials and methods: Rheological characteristics were determined on a Reotest device by the 2 nd method of viscometry Results and discussion. Reasonability of ß-galactosidase use for milk lactose hydrolyze during the production of canned products with sugar was proved in the previous works. This technology gives possibility to increase the quality of condensed canned foods, to reduce sugar concentration till 50 %, to increase dietary properties. Due to the reducing of saccharose mass part till 22 and 31 % the products had a liquid consistency that’s why was a necessity to increase the viscosity properties of condensed products. One of method to increase the product viscosity is inoculation of stabilization systems. Reasonability of the usage of stabilization system Bivicioc 1L was proved. The researches of viscosity determination in whole hydrolyzed sweetened condensed milk were shown in the work. Relations of viscosity of whole hydrolyzed condensed milk to the deformation rate were presented. Conclusions Viscosity indices of experimental samples in the fresh produced products and during storage are determined and justified.

  9. Universal properties of bulk viscosity near the QCD phase transition

    CERN Document Server

    Karsch, F; Tuchin, K

    2008-01-01

    We extract the bulk viscosity of hot quark-gluon matter in the presence of light quarks from the recent lattice data on the QCD equation of state. For that purpose we extend the sum rule analysis by including the contribution of light quarks. We also discuss the universal properties of bulk viscosity in the vicinity of a second order phase transition, as it might occur in the chiral limit of QCD at fixed strange quark mass and most likely does occur in two-flavor QCD. We point out that a chiral transition in the O(4) universality class at zero baryon density as well as the transition at the chiral critical point which belongs to the Z(2) universality class both lead to the critical behavior of bulk viscosity. In particular, the latter universality class implies the divergence of the bulk viscosity, which may be used as a signature of the critical point. We discuss the physical picture behind the dramatic increase of bulk viscosity seen in our analysis, and devise possible experimental tests of related phenome...

  10. Integrated Optofluidic Chip for Low-Volume Fluid Viscosity Measurement

    Directory of Open Access Journals (Sweden)

    Tie Yang

    2017-02-01

    Full Text Available In the present work, an integrated optofluidic chip for fluid viscosity measurements in the range from 1 mPa·s to 100 mPa·s is proposed. The device allows the use of small sample volumes (<1 µL and the measurement of viscosity as a function of temperature. Thanks to the precise control of the force exerted on dielectric spheres by optical beams, the viscosity of fluids is assessed by comparing the experimentally observed movement of dielectric beads produced by the optical forces with that expected by numerical calculations. The chip and the developed technique are validated by analyzing several fluids, such as Milli-Q water, ethanol and water–glycerol mixtures. The results show a good agreement between the experimental values and those reported in the literature. The extremely reduced volume of the sample required and the high flexibility of this technique make it a good candidate for measuring a wide range of viscosity values as well as for the analysis of nonlinear viscosity in complex fluids.

  11. CFD simulation of blood flow inside the corkscrew collaterals of the Buerger’s disease

    Directory of Open Access Journals (Sweden)

    Alireza Sharifi

    2016-03-01

    Results: The local velocity patterns, pressure and kinematic viscosity distributions in different segments of the corkscrew collateral artery was demonstrated and discussed for the first time for this kind of artery. The effects of non-Newtonian consideration for the blood viscosity behavior were investigated in different segments of the artery. Moreover, the variations of the blood flow patterns along the artery were investigated in details for each segment. Conclusion: It was found that the flow patterns were affected by the complex geometry of this artery in such a way that it could lead to the presence of sites that were prone to the accumulation of the flowing particles in blood like nicotine. Furthermore, due to the existence of many successive bends in this artery, the variations of kinematic viscosity along this artery were significant, therefore the non-Newtonian behavior of the blood viscosity must be considered.

  12. Rheology of fetal and maternal blood.

    Science.gov (United States)

    Reinhart, W H; Danoff, S J; King, R G; Chien, S

    1985-01-01

    Rheological parameters were measured in 10 pairs of mothers and newborns. Whole blood viscosity was similar despite a higher fetal hematocrit (47.0 +/- 5.1 versus 35.5 +/- 12.0%, mean +/- SD, p less than 0.05). When the hematocrit of the suspension of red cells in plasma was adjusted to 45%, the viscosity was significantly lower in the fetal blood over a wide range of shear rates (0.52-208 S-1). The main reason for the lower viscosity in the fetal blood was the lower plasma viscosity as compared to the maternal blood (1.08 +/- 0.05 versus 1.37 +/- 0.08 centipoise, p less than 0.05); this in turn was attributable to a lower total plasma protein concentration (4.74 +/- 0.71 versus 6.47 +/- 0.64 g/dl, p less than 0.05). All protein fractions were lower in the fetal plasma. The assessment of red cell deformability by filtration through polycarbonate sieves revealed that the resistance of a fetal red cell was three times higher than that of a maternal red cell in a 2.6-micron pore, but there was no significant difference in resistance for these red cells in 6.9-micron pores. This higher filtration resistance of fetal red cells through the small pores was mainly due to their large volume (115.4 +/- 10.8 versus 93.5 +/- 5.9 fl, p less than 0.001). Measurements on membrane-free hemoglobin solutions indicated that the internal viscosity of these two types of red cells was not different.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Effect of Xiaoke Granule(消渴冲剂)on Blood Sugar and Blood Rheological Property in Experimental Diabetic Animals

    Institute of Scientific and Technical Information of China (English)

    季晓梅; 刘根尚; 齐昉; 郑虎占; 佘靖; 龚慕辛; 孙军; 章红英

    2002-01-01

    Objective: To study the pharmacological effect of Xiaoke Granule (XKG, 消渴冲剂) on blood sugar and blood rheological property in the diabetic animals.Methods: Alloxan induced diabetic mice or rats were grouped randomly. The effects of XKG on blood sugar, appetite, capacity of drinking, glucose tolerance, blood lipid and blood rheological property were observed and compared among groups.Results:XKG showed a trend in reducing the appetite and capacity of drinking, increasing the body weight, and significantly inhibiting the increase of blood sugar coused by ectogenic glucose in mice, and could improve the blood lipid and blood rheological property in rats.Conclusion:XKG is effective in reducing serum total cholesterol, lowering the blood viscosity, improving the blood rheological property of alloxan induced diabetic animals. Therefore, it might effective in treating and preventing the occurrence of diabetes mellitus and the complications of blood stasis.

  14. Diffusivities and Viscosities of Poly(ethylene oxide) Oligomers †

    KAUST Repository

    Hong, Bingbing

    2010-10-14

    Diffusivities and viscosities of poly(ethylene oxide) (PEO) oligomer melts with 1 to 12 repeat units have been obtained from equilibrium molecular dynamics simulations using the TraPPE-UA force field. The simulations generated diffusion coefficients with high accuracy for all of the molar masses studied, but the statistical uncertainties in the viscosity calculations were significantly larger for longer chains. There is good agreement of the calculated viscosities and densities with available experimental data, and thus, the simulations can be used to bridge gaps in the data and for extrapolations with respect to chain length, temperature, and pressure. We explored the convergence characteristics of the Green-Kubo formulas for different chain lengths and propose minimal production times required for convergence of the transport properties. The chain-length dependence of the transport properties suggests that neither Rouse nor reptation models are applicable in the short-chain regime investigated. © 2010 American Chemical Society.

  15. The viscosity window of the silicate glass foam production

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund; König, Jakob; Yue, Yuanzheng

    2017-01-01

    The production of silicate glass foam allows diverse resources and waste materials to be used in the production. Testing of such large palette of materials complicates and prolongs the optimisation process. Therefore, it is crucial to find a universal criterion for foaming silicate glass melts...... which can offer a practical starting point for the optimisation procedure. The melt viscosity might be the most important parameter for controlling the foaming process and the glass foam density. In this work, we attempt to define a viscosity range in which foaming of different glasses results...... in a maximum of foam expansion. The expansion maximum is obtained for different glasses (labware, E-glass, CRT panel, soda-lime-silica) by foaming with CaCO3 at isokom temperature and from literature data. In general, the viscosity window was found to be within 104–106 Pa s when foaming with MnO2 or metal...

  16. Geometry-dependent viscosity reduction in sheared active fluids

    CERN Document Server

    Słomka, Jonasz

    2016-01-01

    We investigate flow pattern formation and viscosity reduction mechanisms in active fluids by studying a generalized Navier-Stokes model that captures the experimentally observed bulk vortex dynamics in microbial suspensions. We present exact analytical solutions including stress-free vortex lattices and introduce a computational framework that allows the efficient treatment of previously intractable higher-order shear boundary conditions. Large-scale parameter scans identify the conditions for spontaneous flow symmetry breaking, geometry-dependent viscosity reduction and negative-viscosity states amenable to energy harvesting in confined suspensions. The theory uses only generic assumptions about the symmetries and long-wavelength structure of active stress tensors, suggesting that inviscid phases may be achievable in a broad class of non-equilibrium fluids by tuning confinement geometry and pattern scale selection.

  17. Synthesis and Aqueous Solution Viscosity of Hydrophobically Modified Xanthan Gum

    Institute of Scientific and Technical Information of China (English)

    QIAN Xiao-lin; WU Wen-hui; YU Pei-zhi; WANG Jian-quan

    2007-01-01

    Two xanthan gum derivatives hydrophobically modified by 4 or 8 tetradecyl chains per 100 xanthan gum structure units were synthesized. The derivatives were studied by scanning electron microscope and pyrene fluorescence spectrometry. And the aqueous solution apparent viscosity of the derivatives was investigated. The results indicate that the network of the derivatives with more hydrophobic groups is closer and tighter. With increasing of alkyl chain substitution degree, the hydrophobically associating interactions enhance in aqueous solution. Aqueous solution apparent viscosity of the derivatives increases with increasing of polymer concentration and alkyl substitution degree, and decreases with the increase of temperature. In the brine solution, the strong viscosity enhancement phenomenon appears. The interaction between the derivatives and surfactant sodium dodecylbenzene sulfonate is strong.

  18. Boosting Magnetic Reconnection by Viscosity and Thermal Conduction

    CERN Document Server

    Minoshima, Takashi; Imada, Shinsuke

    2016-01-01

    Nonlinear evolution of magnetic reconnection is investigated by means of magnetohydrodynamic simulations including uniform resistivity, uniform viscosity, and anisotropic thermal conduction. When viscosity exceeds resistivity (the magnetic Prandtl number Prm > 1), the viscous dissipation dominates outflow dynamics and leads to the decrease in the plasma density inside a current sheet. The low-density current sheet supports the excitation of the vortex. The thickness of the vortex is broader than that of the current for Prm > 1. The broader vortex flow more efficiently carries the upstream magnetic flux toward the reconnection region, and consequently boosts the reconnection. The reconnection rate increases with viscosity provided that thermal conduction is fast enough to take away the thermal energy increased by the viscous dissipation (the fluid Prandtl number Pr < 1). The result suggests the need to control the Prandtl numbers for the reconnection against the conventional resistive model.

  19. Artificial viscosity in the transonic stream function formulation

    Institute of Scientific and Technical Information of China (English)

    徐建中; 杜建一; 沈浩; 刘海涛

    1995-01-01

    The artificial density method which has been applied widely in the transonic potential calculation and the current transonic stream function calculation is investigated theoretically. The analysis shows that in the stream function formulation the artificial density is not equivalent to the artificial viscosity and cannot be used, and a correct expression of the artificial viscosity in the stream function method is then derived. The principal equation of the stream function, the density equation converted from one of the momentum equations and the present artificial viscosity scheme constitute the complete transonic stream function formulation. The numerical practice demonstrates that the range of Mach number computed by this approach is extended and the shock location is close to the experimental result.

  20. Bulk Viscosity Effects in Event-by-Event Relativistic Hydrodynamics

    CERN Document Server

    Noronha-Hostler, Jacquelyn; Noronha, Jorge; Andrade, Rone P G; Grassi, Frederique

    2013-01-01

    Bulk viscosity effects on the collective flow harmonics in heavy ion collisions are investigated, on an event by event basis, using a newly developed 2+1 Lagrangian hydrodynamic code named v-USPhydro which implements the Smoothed Particle Hydrodynamics (SPH) algorithm for viscous hydrodynamics. A new formula for the bulk viscous corrections present in the distribution function at freeze-out is derived starting from the Boltzmann equation for multi-hadron species. Bulk viscosity is shown to enhance the collective flow Fourier coefficients from $v_2(p_T)$ to $v_5(p_T)$ when $% p_{T}\\sim 1-3$ GeV even when the bulk viscosity to entropy density ratio, $% \\zeta/s$, is significantly smaller than $1/(4\\pi)$.

  1. The Effects of Fluid Viscosity on the Orifice Rotameter

    Directory of Open Access Journals (Sweden)

    Jiang Wei

    2016-04-01

    Full Text Available Due to the viscous shear stress, there is an obvious error between the real flow rate and the rotameter indication for measuring viscous fluid medium. At 50 cSt the maximum error of DN40 orifice rotameter is up to 35 %. The fluid viscosity effects on the orifice rotameter are investigated using experimental and theoretical models. Wall jet and concentric annulus laminar theories were adapted to study the influence of viscosity. And a new formula is obtained for calculating the flow rate of viscous fluid. The experimental data were analyzed and compared with the calculated results. At high viscosity the maximum theoretical results error is 6.3 %, indicating that the proposed measurement model has very good applicability.

  2. MODELING A SOLID BOUNDARY AS A FLUID OF INFINITE VISCOSITY

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new approach to model viscosity in the conservation of momentum equations is presented and discussed. Coefficient of viscosity is modeled in such a way that it reaches asymptotically to infinity at the solid boundary but still yields a finite value for the shear stress at the solid wall. Basic objective of this research is to show that certain combinations of higher order normal velocity gradients become zero at the solid boundary.Modified solutions for the Couette flow and Poiseuille flow between two parallel plates are obtained by modeling the coefficient of viscosity in a novel way. Also,viscous drag computed by our model is expected to yield higher values than the values predicted by the existing models, which matches closely to the experimental data.

  3. Variable viscosity condition in the modeling of a slider bearing

    CERN Document Server

    Uprety, Kedar Nath

    2014-01-01

    To reduce tear and wear of machinery lubrication is essential. Lubricants form a layer between two surfaces preventing direct contact and reduce friction between moving parts and hence reduce wear. In this short letter the lubrication of two slider bearings with parallel and nonparallel is studied. First, we show that bearings with parallel plates cannot support any load. For bearings with nonparallel plates we are interested on how constant and temperature dependent viscosity affects the properties of the bearings. Also, a critical temperature for which the bearings would fail due to excess in temperature is found for both latter cases. If the viscosity is constant, the critical temperature is given by an explicit formula, while for the non-constant viscosity the critical temperature can be always found from a closed form formula involving Weber functions

  4. Viscosity in cosmological simulations of clusters of galaxies

    CERN Document Server

    Br"uggen, M

    2005-01-01

    The physics of the intracluster medium, in particular the values for the thermal conductivity and the viscosity are largely unknown and subject to an ongoing debate. Here, we study the effect of viscosity on the thermal state of the intracluster medium using three-dimensional cosmological simulations of structure formation. It is shown that viscosity, provided it is not too far off from the unmagnetised Spitzer value, has a significant effect on cluster profiles. In particular, it aids in heating the cool cores of clusters. The central cooling time of the most massive clusters in our simulation is increased by more than an order of magnitude. In large clusters, viscous heating may help to establish an entropy floor and to prevent a cooling catastrophe.

  5. VISCOSITY BEHAVIOR OF LACQUER POLYSACCHARIDE IN AQUEOUS SOLUTION

    Institute of Scientific and Technical Information of China (English)

    QIU Xingping; ZHANG Lina; DU Yumin; QIAN Baogong

    1991-01-01

    The dependence of measured viscosity on NaCl concentration (0.1 to 3.0M), pH (range of 2-13) and cadoxen composition Wcad (from 2% to 100% ) for the lacquer polysaccharide in NaCl/cadoxen/H2O mixture containing HCl or without were obtained. All the viscosity exponents γ in the Mark-Houwink equations under three different solvent condition are close to 0.5. The wcad dependence of reduced viscosity ηsp/c confirms the single strand chain of the polysaccharide. As the γ values close to 0.5 and values of unperturbed dimension θ/M and [η] much smaller than those for usual linear polymers, these facts suggest that the polysaccharide chains in the aqueous solutions should be dense random coil owing to the highly branched structure.

  6. In situ viscosity measurements of albite melt under high pressure

    CERN Document Server

    Funakoshi, K I; Terasaki, H

    2002-01-01

    The viscosities of albite (NaAlSi sub 3 O sub 8) melt under high pressures have been measured using an x-ray radiography falling sphere method with synchrotron radiation. This method has enabled us to determine the precise sinking velocity directly. Recent experiments of albite melt showed the presence of a viscosity minimum around 5 GPa (Poe et al 1997 Science 276 1245, Mori et al 2000 Earth Planet. Sci. Lett. 175 87). We present the results for albite melt up to 5.2 GPa at 1600 and 1700 deg. C. The viscosity minimum is clearly observed to be around 4.5 GPa, and it might be explained not by the change of the compression mechanism in albite melt but by change of the phase itself.

  7. Viscosities of Binary Mixtures Containing Isomeric Chlorobutanes and Diisopropylether: Experimental and Predicted Values

    Science.gov (United States)

    Montaño, D.; Guerrero, H.; Bandrés, I.; López, M. C.; Lafuente, Carlos

    2010-03-01

    In this work, viscosities of binary mixtures of isomeric chlorobutanes with diisopropylether have been determined as a function of composition under atmospheric pressure and in the temperature range from 283.15 K to 313.15 K with steps of 5 K. Kinematics viscosities were measured using an Ubbelohde viscosimeter; absolute viscosities were obtained from kinematic viscosities and densities. Finally, we have used the Asfour method for predicting the dependence of viscosity with composition and comparing it with our experimental data.

  8. Viscosity Formulations and the Effect of Uncertain Parameters

    Science.gov (United States)

    Wasiliev, J. M.

    2015-12-01

    The development of detailed models of the interior of the Earth and other terrestrial planets is frequently hampered by poorly constrained compositional parameters, namely Activation Energy and Volume, which are necessary to define Arrhenius viscosity. This results in the values of said parameters varying considerably to suit the needs of individual investigations. A computational exploration of the effects of Activation Energy and Volume on the Earth's mantle was thus conducted, with a view to developing a robust and versatile method for obtaining a first-degree approximation for the parameter values, and providing some context for future studies. A wide range of plausible mantle configurations was examined in both one and two dimensions, with the latter case utilising the modelling program ASPECT to generate a series of simple Earth-like planets which were allowed to evolve until a steady state was achieved. A comprehensive statistical analysis was then performed, allowing for suitable parameter values to be more effectively constrained for numerous given viscosity formulations. Activation Energy was seen to exhibit considerable influence over the bulk magnitude of viscosity values, while Activation Volume heavily impacted the viscosity contrast between the upper and lower mantle. This behaviour stems from the parameters controlling the temperature and pressure dependency of viscosity within the calculation. Results were found to be highly dependent on the minimum and maximum values imposed on the viscosity, reinforcing the need for a fuller understanding of the formulation. A notable impact on stress profiles, and hence tectonic regime, was also observed. As such similar calculations were performed on directly scaled Super-Earths, with the intention of providing some insight into scenarios conducive to particular tectonic regimes in planets outside our solar system.

  9. [The viscosity of Thiokol impression material during gelation (author's transl)].

    Science.gov (United States)

    Araki, Y; Kawakami, M

    1976-09-01

    Viscosity behavior of the impression materials is important property which determines the pressure and its distribution to be exerted on oral soft tissues in relation to the tray design and impression technique. The impression material, however, react to gel so fast to measure the viscosity during the reaction that it is still not completely elucidated. It would be able to seize the viscosity behavior of Thiokol impression material during the gelation unequivocally by retarding the oxidative condensation reaction using weak oxidative, lead monoxide. Based on the equal reactivity of SH groups of Thiokol liquid polymer there is no difference in statistic molecular weight distribution at any degree of the reaction between with lead monoxide and with the other oxidatives now in practical use. The viscosity measurement of the mixture of Thiokol LP-2, lead monoxide, and di-butyl phthalate was performed at the rates of shear ranged from 10(1.5) to 10(3.9) sec-1 at 20 degrees C. The viscosity of the mixture progressively increases after spatulation of the materials but yield value does not appear for the time being before setting, that is, the infinite network forming via the pendant SH groups could not take place until the most of SH groups were consumed, attributed to low concentration of poly-functional prepolymer in the liquid polymer. At early stages of the reaciton the viscosity behavior is approximately Newtonian at lower rates of shear and pseudplastic at higher rates of shear. As the reaction proceeds it becomes pseudplastic even at lower rates of shear.

  10. VISCOSITY ANALYSIS OF EMPTY FRUIT BUNCH (EFB BIO-OIL

    Directory of Open Access Journals (Sweden)

    Z.S. Nazirah

    2013-12-01

    Full Text Available Empty fruit bunches (EFB are one of the solid wastes produced by the palm oil industry, which is increasing rapidly. The aim of this paper is to analyse the viscosity of empty fruit bunch (EFB bio-oil that can be extracted from all solid waste EFB as a sample, and a few processes were executed. The samples underwent two processes, which were pre-treatment and pyrolysis. The pre-treatment involved three processes, namely, cutting, shredding and sieving, which were necessary in order to prepare EFB into a particle size suitable for the reactor. After that, the samples were fed into the feedback reactor as feedstock for the pyrolysis process to produce bio-oil. Once the bio-oil was produced, its viscosity was tested using the Brookfield Viscometer in two conditions: before and after the chemical reaction. The bio-oil was treated by adding 10 ml and 20 ml of acetone respectively through the chemical reaction. The viscosity test was carried out at different temperatures, which were 25°C, 30°C, 35°C, 40°C, 45°C and 50°C respectively. The observed viscosity of the EFB bio-oil varied and was higher as the temperature decreased. In addition, the viscosity of the EFB bio-oil was higher when it reacted chemically with the acetone added. Therefore, the results showed that the chemical reaction with acetone has the potential to increase the viscosity of EFB bio-oil.

  11. Cosmology with bulk viscosity and the gravitino problem

    CERN Document Server

    Buoninfante, L

    2016-01-01

    The gravitino problem is revisited in the framework of cosmological models in which the primordial cosmic matter is described by a relativistic imperfect fluid. Dissipative effects (or bulk viscosity effects) arise owing to the different cooling rates of the fluid components. We show that the effects of the bulk viscosity allow to avoid the late abundance of gravitinos. In particular, we found that for a particular choice of the parameters characterizing the cosmological model, the gravitino abundance turns out to be independent on the reheating temperature.

  12. Study on Apparent Viscosity and Structure of Foaming Slag

    Science.gov (United States)

    Martinsson, Johan; Glaser, Björn; Sichen, Du

    2016-10-01

    Foaming slag was generated using induction heating. The foam was found non-Newtonian having much higher apparent viscosity compared to the dynamic viscosity of pure slag. Quenched foam was examined. The appearance of the foaming slag was very different from silicone oil-gas foam. The size of gas bubbles ranged from 0.1 to 4 mm (while in the case of silicone oil, 1 to 2 mm). The gas fraction in the foam was considerably lower than in the case of silicone oil.

  13. Viscosity measurement in thin lubricant films using shear ultrasonic reflection

    OpenAIRE

    S. Kasolang; Dwyer-Joyce, R.S.

    2008-01-01

    When a shear ultrasonic wave is incident on a solid and liquid boundary, the proportion that is reflected depends on the liquid viscosity. This is the basis for some instruments for on-line measurement of bulk liquid viscosity. In machine elements, the lubricant is usually present in a thin layer between two rubbing solid surfaces. The thin film has a different response to an ultrasonic shear wave than liquid in bulk. In this work, this response is investigated with the aim of measuring visco...

  14. Mathematical Viscosity Models for Ternary Metallic and Silicate Melts

    Institute of Scientific and Technical Information of China (English)

    FU Yuan-kun; MENG Xian-min; GUO Han-jie

    2004-01-01

    The mathematical viscosity models for metallic melts were discussed. The experimental data of Ag-Au-Cu systems were used to verify the models based on Chou's general geometric thermodynamic model and the calculated results are consistent with the reported experimental data. A new model predicting the viscosity of multi-component silicate melts was established. The CaO-MnO-SiO2, CaO-FeO-SiO2 and FeO-MnO-SiO2 silicate slag systems were used to verify the model.

  15. Quantifying the Efficiency Advantages of High Viscosity Index Hydraulic Fluids

    Institute of Scientific and Technical Information of China (English)

    Christian D. Neveu; Michael D. Zink; Alex Tsay

    2006-01-01

    By providing higher in- use viscosity at elevated operating temperatures, hydraulic fluids with high viscosity index improve the efficiency of the hydraulic system. For mobile hydraulic equipment this efficiency can be quantified as an increase in fuel economy. This paper reviews the research that demonstrates these efficiency advantages in gear, vane and piston pumps and presents a method for predicting the overall fuel economy for a fleet of hydraulic equipment in opquipment operator to easily improve the performance of the system and reduce fuel consumption.

  16. Density and viscosity modeling and characterization of heavy oils

    DEFF Research Database (Denmark)

    Cisneros, Sergio; Andersen, Simon Ivar; Creek, J

    2005-01-01

    are widely used within the oil industry. Further work also established the basis for extending the approach to heavy oils. Thus, in this work, the extended f-theory approach is further discussed with the study and modeling of a wider set of representative heavy reservoir fluids with viscosities up...... to thousands of mPa center dot s. Essential to the presented extended approach for heavy oils is, first, achievement of accurate P nu T results for the EOS-characterized fluid. In particular, it has been determined that, for accurate viscosity modeling of heavy oils, a compressibility correction in the way...

  17. NVP melt/magma viscosity: insight on Mercury lava flows

    Science.gov (United States)

    Rossi, Stefano; Morgavi, Daniele; Namur, Olivier; Vetere, Francesco; Perugini, Diego; Mancinelli, Paolo; Pauselli, Cristina

    2016-04-01

    After more than four years of orbiting Mercury, NASA's MESSENGER spacecraft came to an end in late April 2015. MESSENGER has provided many new and surprising results. This session will again highlight the latest results on Mercury based on MESSENGER observations or updated modelling. The session will further address instrument calibration and science performance both retrospective on MESSENGER and on the ESA/JAXA BepiColombo mission. Papers covering additional themes related to Mercury are also welcomed. Please be aware that this session will be held as a PICO session. This will allow an intensive exchange of expertise and experience between the individual instruments and mission. NVP melt/magma viscosity: insight on Mercury lava flows S. Rossi1, D. Morgavi1, O. Namur2, D. Perugini1, F.Vetere1, P. Mancinelli1 and C. Pauselli1 1 Dipartimento di Fisica e Geologia, Università di Perugia, piazza Università 1, 06123 Perugia, Italy 2 Uni Hannover Institut für Mineralogie, Leibniz Universität Hannover, Callinstraβe 3, 30167 Hannover, Germany In this contribution we report new measurements of viscosity of synthetic komatitic melts, used the behaviour of silicate melts erupted at the surface of Mercury. Composition of Mercurian surface magmas was calculated using the most recent maps produced from MESSENGER XRS data (Weider et al., 2015). We focused on the northern hemisphere (Northern Volcanic Province, NVP, the largest lava flow on Mercury and possibly in the Solar System) for which the spatial resolution of MESSENGER measurements is high and individual maps of Mg/Si, Ca/Si, Al/Si and S/Si were combined. The experimental starting material contains high Na2O content (≈7 wt.%) that strongly influences viscosity. High temperature viscosity measurements were carried out at 1 atm using a concentric cylinder apparatus equipped with an Anton Paar RheolabQC viscometer head at the Department of Physics and Geology (PVRG_lab) at the University of Perugia (Perugia, Italy

  18. Viscosity-Induced Crossing of the Phantom Barrier

    Directory of Open Access Journals (Sweden)

    Iver Brevik

    2015-09-01

    Full Text Available We show explicitly, by using astrophysical data plus reasonable assumptions for the bulk viscosity in the cosmic fluid, how the magnitude of this viscosity may be high enough to drive the fluid from its position in the quintessence region at present time t = 0 across the barrier w = −1 into the phantom region in the late universe. The phantom barrier is accordingly not a sharp mathematical divide, but rather a fuzzy concept. We also calculate the limiting forms of various thermodynamical quantities, including the rate of entropy production, for a dark energy fluid near the future Big Rip singularity.

  19. Time Dependent and Steady Uni-axial Elongational Viscosity

    DEFF Research Database (Denmark)

    Nielsen, Jens K.; Rasmussen, Henrik Koblitz; Hassager, Ole

    2005-01-01

    Here we present measurements of transient and steady uni-axial elongational viscosity, using the Filament Stretching Rheometer1 or FSR1 (see Fig. 1) of the following melts: Four narrow MMD polystyrene (PS) samples with weight-average molar mass Mw in the range of 50k to 390k. Three different bi......-disperse samples, mixed from the narrow MMD PS. Two low-density polyethylene (LDPE) melts (Lupolen 1840D and 3020D). A steady-state viscosity was kept for 1-2.5 Hencky strain units in all measurements....

  20. Bianchi Type Ⅲ String Cosmological Model with Bulk Viscosity

    Institute of Scientific and Technical Information of China (English)

    WANGXing-Xiang

    2004-01-01

    The Bianchi type Ⅲ cosmological model for a cloud string with bulk viscosity are presented. To obtain a determinate model, an equation of state ρ=kλ and a relation between metric potentials B = Cn are assumed. The physical and geometric aspects of the model are also discussed. The model describes a shearing non-rotating continuously expanding universe with a big-bang start, and the relation between the coefficient of bulk viscosity and the energy density is ζ∝ρ1/2.

  1. Bianchi Type Ⅲ String Cosmological Model with Bulk Viscosity

    Institute of Scientific and Technical Information of China (English)

    WANG Xing-Xiang

    2004-01-01

    The Bianchi type Ⅲ cosmological model for a cloud string with bulk viscosity are presented. To obtaina determinate model, an equation of state p = κλ and a relation between metric potentials B = Cn are assumed. Thephysical and geometric aspects of the model are also discussed. The model describes a shearing non-rotating continuouslyexpanding universe with a big-bang start, and the relation between the coefficient of bulk viscosity and the energy densityis ζ∝1 p1/2.

  2. RECENT PROGRESS IN NONLINEAR EDDY-VISCOSITY TURBULENCE MODELING

    Institute of Scientific and Technical Information of China (English)

    符松; 郭阳; 钱炜祺; 王辰

    2003-01-01

    This article presents recent progresses in turbulence modeling in the Unit for Turbulence Simulation in the Department of Engineering Mechanics at Tsinghua University. The main contents include: compact Non-Linear Eddy-Viscosity Model (NLEVM) based on the second-moment closure, near-wall low-Re non-linear eddy-viscosity model and curvature sensitive turbulence model.The models have been validated in a wide range of complex flow test cases and the calculated results show that the present models exhibited overall good performance.

  3. Comparative toxicokinetics of low-viscosity mineral oil in Fischer 344 rats, Sprague-Dawley rats, and humans--implications for an Acceptable Daily Intake (ADI).

    Science.gov (United States)

    Boogaard, Peter J; Goyak, Katy O; Biles, Robert W; van Stee, Leo L P; Miller, Matthew S; Miller, Mary Jo

    2012-06-01

    Oral repeated-dose studies with low-viscosity mineral oils showed distinct species and strain differences, which are hypothesized to be due to differences in bioavailability, with Fischer 344 rats being more susceptible than Sprague-Dawley rats or dogs. Sensitive analytical methodology was developed for accurate measurement of low levels of mineral hydrocarbons and applied in single-dose toxicokinetics studies in rats and humans. Fischer 344 rats showed a 4-fold higher AUC(0-∞) and consistently higher blood and liver concentrations were found than Sprague-Dawley rats. Hepatic mineral hydrocarbon concentration tracked the blood concentration in both strains, indicating that blood concentrations can serve as functional surrogate measure for hepatic concentrations. In human volunteers receiving 1mg/kg body weight of low-viscosity white oil, all blood concentrations of mineral hydrocarbons were below the detection limit. Comparison with threshold blood concentrations associated with NOAELs in both rat strains, indicate that the margin-of-exposure is at least 37-fold. Using an internal dose metric rather than applied dose reduces the uncertainty around the temporary ADI considerably since it intrinsically accounts for intra- and inter-species differences. The current data support replacement of the temporary ADI of 0.01 mg/kg/day by a (permanent) ADI of at least 1.0mg/kg/day for low- and medium-viscosity mineral oils.

  4. Viscosities and viscosity deviations of binary mixtures of biodiesel + petrodiesel (or n-hexadecane at different temperatures

    Directory of Open Access Journals (Sweden)

    F. M. R. Mesquita

    2012-09-01

    Full Text Available Viscosities of four binaries mixtures [soybean biodiesel + diesel oil (or n-hexadecane and coconut biodiesel + diesel oil (or n-hexadecane] have been determined at T = (293.15, 313.15, 333.15, 353.15, 373.15 K and atmospheric pressure over the entire composition range. Experimental data were fitted to the Andrade equation and the adjustable parameters and the standard deviations between experimental and calculated values were estimated. From the experimental data, the viscosity deviations, , were calculated by using the Redlich - Kister polynomial equation. The comparison between experimental data determined in this work and four predictive methods used for the estimation of viscosities of biodiesel fuels (based on their fatty acid composition is discussed.

  5. Effects of viscosity on endothelial cell damage under acoustic droplet vaporization

    Science.gov (United States)

    Seda, Robinson; Singh, Rahul; Li, David; Pitre, John; Putnam, Andrew; Fowlkes, J. Brian; Bull, Joseph

    2014-11-01

    Acoustic droplet vaporization (ADV) is a process by which stabilized superheated microdroplets are able to undergo phase transition with the aid of focused ultrasound. Gas bubbles resulting from ADV can provide local occlusion of the blood vessels supplying diseased tissue, such as tumors. The ADV process can also induce bioeffects that increase vessel permeability, which is beneficial for localized drug delivery. Previous in vitro studies have demonstrated that vaporization at the endothelial layer will affect cell attachment and viability. Several hypotheses have been proposed to elucidate the mechanism of damage including the generation of normal and shear stresses during bubble expansion. A single 3.5 MHz ultrasound pulse consisting of 8 cycles (~2.3 μs) and a 6 MPa peak rarefactional pressure was used to induce ADV on endothelial cells in media of different viscosities. Carboxylmethyl cellulose was added to the cell media to increase the viscosity up to 300 cP to and aid in the reduction of stresses during bubble expansion. The likelihood of cell damage was decreased when compared to our control (~1 cP), but it was still present in some cases indicating that the mechanism of damage does not depend entirely on viscous stresses associated with bubble expansion. This work was supported by NIH Grant R01EB006476.

  6. Artificial blood

    Directory of Open Access Journals (Sweden)

    Sarkar Suman

    2008-01-01

    Full Text Available Artificial blood is a product made to act as a substitute for red blood cells. While true blood serves many different functions, artificial blood is designed for the sole purpose of transporting oxygen and carbon dioxide throughout the body. Depending on the type of artificial blood, it can be produced in different ways using synthetic production, chemical isolation, or recombinant biochemical technology. Development of the first blood substitutes dates back to the early 1600s, and the search for the ideal blood substitute continues. Various manufacturers have products in clinical trials; however, no truly safe and effective artificial blood product is currently marketed. It is anticipated that when an artificial blood product is available, it will have annual sales of over $7.6 billion in the United States alone.

  7. Artificial blood.

    Science.gov (United States)

    Sarkar, Suman

    2008-07-01

    Artificial blood is a product made to act as a substitute for red blood cells. While true blood serves many different functions, artificial blood is designed for the sole purpose of transporting oxygen and carbon dioxide throughout the body. Depending on the type of artificial blood, it can be produced in different ways using synthetic production, chemical isolation, or recombinant biochemical technology. Development of the first blood substitutes dates back to the early 1600s, and the search for the ideal blood substitute continues. Various manufacturers have products in clinical trials; however, no truly safe and effective artificial blood product is currently marketed. It is anticipated that when an artificial blood product is available, it will have annual sales of over $7.6 billion in the United States alone.

  8. Measurement of gas viscosity using photonic crystal fiber

    Science.gov (United States)

    Gao, R.-K.; Sheehe, S. L.; Kurtz, J.; O'Byrne, S.

    2016-11-01

    A new measurement technique for gas viscosity coefficient is designed and demonstrated using the technique of tunable diode laser absorption spectroscopy (TDLAS). Gas flow is driven by a pressure gradient between two gas cells, through a photonic crystal fiber (PCF) surrounded by a furnace for temperature adjustment. PCF with 20-micron diameter affords physical space for gas-light interaction and provides a basis for gas viscosity measurement by determining the time for flow to exit a capillary tube under the influence of a pressure gradient. Infrared radiation from a diode laser is coupled into the fiber to be guided through the gas, and the light attenuation due to absorption from the molecular absorbing species is measured by a photo detector placed at the exit of the fiber. A numerical model from Sharipov and Graur describing local number density distribution in a unsteady state is applied for the determination of gas viscosity, based on the number density of gas measured by the absorption of the laser light, using the Beer-Lambert law. The measurement system is confirmed by measuring the viscosity of CO2 as a reference gas.

  9. Temperature Relations of Selected Engine Oils Dynamic Viscosity

    Directory of Open Access Journals (Sweden)

    Hlaváč Peter

    2014-12-01

    Full Text Available This article focuses on temperature relations of dynamic viscosity for selected engine oils. The effect of temperature on new and used oil dynamic viscosity was investigated. Measurements were performed on three different motor oil samples. All the three motor oil samples were synthetic. The first oil sample was new, the second sample was used for 15,000 km, and the third sample was used for 30,000 km. There were made two measurements of samples in one week. Dynamic viscosity was measured using a digital rotational viscometer Anton Paar DV-3P. The principle of measurement is based on the dependence of sample resistance to probe rotation. The results of measurements are shown as graphical relationships between dynamic viscosity and temperature. Decreasing exponential functions in temperature relationships were used for all the samples. The highest difference between the first and second measurement was observed in the new oil, and very small differences were found in other oils. Due to different types of oils and different stage of usage, the results could not be compared.

  10. Upper mantle viscosity and lithospheric thickness under Iceland

    NARCIS (Netherlands)

    Barnhoorn, A.; Wal, W. van der; Drury, M.R.

    2011-01-01

    Deglaciation during the Holocene on Iceland caused uplift due to glacial isostatic adjustment. Relatively low estimates for the upper mantle viscosity and lithospheric thickness result in rapid uplift responses to the deglaciation cycles on Iceland. The relatively high temperatures of the upper mant

  11. Shear viscosity of the $\\Phi^4$ theory from classical simulation

    CERN Document Server

    Homor, M M

    2015-01-01

    Shear viscosity of the classical $\\Phi^4$ theory is measured using classical microcanonical simulation. To calculate the Kubo formula, we measure the energy-momentum tensor correlation function, and apply the Green-Kubo relation. Being a classical theory, the results depend on the cutoff which should be chosen in the range of the temperature. Comparison with experimentally accessible systems is also performed.

  12. Effect of Fluid Dynamic Viscosity on the Strength of Chalk

    DEFF Research Database (Denmark)

    Hedegaard, K.; Fabricius, Ida Lykke

    The mechanical strength of high porosity and weakly cemented chalk is affected by the fluid in the pores. In this study, the effect of the dynamic viscosity of non-polar fluids has been measured on outcrop chalk from Sigerslev Quarry, Stevns, Denmark. The outcome is that the measured strength...

  13. High-viscosity fluid threads in weakly diffusive microfluidic systems

    Science.gov (United States)

    Cubaud, T.; Mason, T. G.

    2009-07-01

    We provide an overview of the flow dynamics of highly viscous miscible liquids in microfluidic geometries. We focus on the lubricated transport of high-viscosity fluids interacting with less viscous fluids, and we review methods for producing and manipulating single and multiple core-annular flows, i.e. viscous threads, in compact and plane microgeometries. In diverging slit microchannels, a thread's buckling instabilities can be employed for generating ordered and disordered miscible microstructures, as well as for partially blending low- and high-viscosity materials. The shear-induced destabilization of a thread that flows off-center in a square microchannel is examined as a means for continuously producing miscible dispersions. We show original compound threads and viscous dendrites that are generated using three fluids, each of which has a large viscosity contrast with the others. Thread motions in zones of microchannel extensions are examined in both miscible and immiscible environments. We demonstrate that high-viscosity fluid threads in weakly diffusive microfluidic systems correspond to the viscous primary flow and can be used as a starting point for studying and understanding the destabilizing effects of interfacial tension as well as diffusion. Characteristic of lubricated transport, threads facilitate the transport of very viscous materials in small fluidic passages, while mitigating dissipation. Threads are also potentially promising for soft material synthesis and diagnostics with independent control of the thread specific surface and residence time in micro-flow reactors.

  14. Measurement of viscosity of gaseous mixtures at atmospheric pressure

    Science.gov (United States)

    Singh, J. J.; Mall, G. H.; Chegini, H.

    1986-01-01

    Coefficients of viscosity of various types of gas mixtures, including simulated natural-gas samples, have been measured at atmospheric pressure and room temperature using a modified capillary tube method. Pressure drops across the straight capillary tube section of a thermal mass flowmeter were measured for small, well-defined, volume flow rates for the test gases and for standard air. In this configuration, the flowmeter provides the volumetric flow rates as well as a well-characterized capillary section for differential pressure measurements across it. The coefficients of viscosity of the test gases were calculated using the reported value of 185.6 micro P for the viscosity of air. The coefficients of viscosity for the test mixtures were also calculated using Wilke's approximation of the Chapman-Enskog (C-E) theory. The experimental and calculated values for binary mixtures are in agreement within the reported accuracy of Wilke's approximation of the C-E theory. However, the agreement for multicomponent mixtures is less satisfactory, possible because of the limitations of Wilkes's approximation of the classical dilute-gas state model.

  15. Viscosity Coefficient Curve Fits for Ionized Gas Species Grant Palmer

    Science.gov (United States)

    Palmer, Grant; Arnold, James O. (Technical Monitor)

    2001-01-01

    Viscosity coefficient curve fits for neutral gas species are available from many sources. Many do a good job of reproducing experimental and computational chemistry data. The curve fits are usually expressed as a function of temperature only. This is consistent with the governing equations used to derive an expression for the neutral species viscosity coefficient. Ionized species pose a more complicated problem. They are subject to electrostatic as well as intermolecular forces. The electrostatic forces are affected by a shielding phenomenon where electrons shield the electrostatic forces of positively charged ions beyond a certain distance. The viscosity coefficient for an ionized gas species is a function of both temperature and local electron number density. Currently available curve fits for ionized gas species, such as those presented by Gupta/Yos, are a function of temperature only. What they did was to assume an electron number density. The problem is that the electron number density they assumed was unrealistically high. The purpose of this paper is two-fold. First, the proper expression for determining the viscosity coefficient of an ionized species as a function of both temperature and electron number density will be presented. Then curve fit coefficients will be developed using the more realistic assumption of an equilibrium electron number density. The results will be compared against previous curve fits and against highly accurate computational chemistry data.

  16. Bulk and shear viscosities for the Gribov-Zwanziger plasma

    Directory of Open Access Journals (Sweden)

    Florkowski Wojciech

    2016-01-01

    Full Text Available The concept of the Gribov-Zwanziger plasma is introduced and used to calculate the bulk and shear viscosities of the system of gluons. The kinetic coeffcients are obtained in two different ways which are shown to yield equivalent results.

  17. A synthesis of similarity and eddy-viscosity models

    NARCIS (Netherlands)

    Verstappen, R.; Friedrich, R; Geurts, BJ; Metais, O

    2004-01-01

    In large-eddy simulation, a low-pass spatial filter is usually applied to the Navier-Stokes equations. The resulting commutator of the filter and the nonlinear term is usually modelled by an eddy-viscosity model, by a similarity model or by a mix thereof. Similarity models possess the proper mathema

  18. Green-Kubo Representation of the Viscosity of Granular Gases

    Science.gov (United States)

    2005-07-13

    Green-Kubo representation of the viscosity of granular gases J. Javier Brey Área de Física Teórica, Universidad de Sevilla. Apartado de Correos 1065...NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Área de Física Teórica, Universidad de Sevilla. Apartado de Correos

  19. Measurement of Viscosity of Hydrocarbon Liquids Using a Microviscometer

    DEFF Research Database (Denmark)

    Dandekar, Abhijit; Andersen, Simon Ivar; Stenby, Erling Halfdan

    1998-01-01

    The viscosity of normal alkanes, their mixtures, and true boiling point (TBP) fractions (C (sub 6) -C (sub 19)) of four North Sea petroleum reservoir fluids have been measured by use of an automatic rolling ball mixroviscometer at 20°C. The equipment is specially suited for samples of limited amo...

  20. Bistability in a simple fluid network due to viscosity contrast

    CERN Document Server

    Geddes, John B; Gardner, David; Carr, Russell T

    2009-01-01

    We study the existence of multiple equilibrium states in a simple fluid network using Newtonian fluids and laminar flow. We demonstrate theoretically the presence of hysteresis and bistability, and we confirm these predictions in an experiment using two miscible fluids of different viscosity--sucrose solution and water. Possible applications include bloodflow, microfluidics, and other network flows governed by similar principles.

  1. Viscosity of aqueous and cyanate ester suspensions containing alumina nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Lawler, Katherine [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    The viscosities of both aqueous and cyanate ester monomer (BECy) based suspensions of alumina nanoparticle were studied. The applications for these suspensions are different: aqueous suspensions of alumina nanoparticles are used in the production of technical ceramics made by slip casting or tape casting, and the BECy based suspensions are being developed for use in an injection-type composite repair resin. In the case of aqueous suspensions, it is advantageous to achieve a high solids content with low viscosity in order to produce a high quality product. The addition of a dispersant is useful so that higher solids content suspensions can be used with lower viscosities. For BECy suspensions, the addition of nanoparticles to the BECy resin is expected to enhance the mechanical properties of the cured composite. The addition of saccharides to aqueous suspensions leads to viscosity reduction. Through DSC measurements it was found that the saccharide molecules formed a solution with water and this resulted in lowering the melting temperature of the free water according to classic freezing point depression. Saccharides also lowered the melting temperature of the bound water, but this followed a different rule. The shear thinning and melting behaviors of the suspensions were used to develop a model based on fractal-type agglomeration. It is believed that the structure of the particle flocs in these suspensions changes with the addition of saccharides which leads to the resultant viscosity decrease. The viscosity of the BECy suspensions increased with solids content, and the viscosity increase was greater than predicted by the classical Einstein equation for dilute suspensions. Instead, the Mooney equation fits the viscosity behavior well from 0-20 vol% solids. The viscosity reduction achieved at high particle loadings by the addition of benzoic acid was also investigated by NMR. It appears that the benzoic acid interacts with the surface of the alumina particle which may

  2. Intrinsic Viscosity of Flexible Polymers in Couette and Poiseuille Flows

    NARCIS (Netherlands)

    van Vliet, Johannes; Brinke, G. ten

    1992-01-01

    The zero-shear-rate intrinsic viscosity of a flexible polymer confined in a slit in Couette and Poiseuille flow is investigated by Monte Carlo simulations of self-avoiding random walks on a simple cubic lattice and by analytical calculations in the free-draining limit. In the simulations an equilibr

  3. Effective viscosity of non-gravitactic Chlamydomonas Reinhardtii microswimmer suspensions

    CERN Document Server

    Mussler, Matthias; Peyla, Philippe; Wagner, Christian

    2013-01-01

    Active microswimmers are known to affect the macroscopic viscosity of suspensions in a more complex manner than passive particles. For puller-like microswimmers an increase in the viscosity has been observed. It has been suggested that the persistence of the orientation of the microswimmers hinders the rotation that is normally caused by the vorticity. It was previously shown that some sorts of algaes are bottom-heavy swimmers, i.e. their centre of mass is not located in the centre of the body. In this way, the algae affects the vorticity of the flow when it is perpendicular oriented to the axis of gravity. This orientation of gravity to vorticity is given in a rheometer that is equipped with a cone-plate geometry. Here we present measurements of the viscosity both in a cone-plate and a Taylor-Couette cell. The two set-ups yielded the same increase in viscosity although the axis of gravitation in the Taylor-Couette cell is parallel to the direction of vorticity. In a complementary experiment we tested the ori...

  4. Hall viscosity and electromagnetic response of electrons in graphene

    Science.gov (United States)

    Sherafati, Mohammad; Principi, Alessandro; Vignale, Giovanni

    2016-09-01

    We derive an analytic expression for the geometric Hall viscosity of noninteracting electrons in a single graphene layer in the presence of a perpendicular magnetic field. We show that a recently derived formula in C. Hoyos and D. T. Son [Phys. Rev. Lett. 108, 066805 (2012), 10.1103/PhysRevLett.108.066805], which connects the coefficient of q2 in the wave-vector expansion of the Hall conductivity σx y(q ) of the two-dimensional electron gas (2DEG) to the Hall viscosity and the orbital diamagnetic susceptibility of that system, continues to hold for graphene, in spite of the lack of Galilean invariance, with a suitable definition of the effective mass. We also show that, for a sufficiently large number of occupied Landau levels in the positive-energy sector, the Hall conductivity of electrons in graphene reduces to that of a Galilean-invariant 2DEG with an effective mass given by ℏ kF/vF (cyclotron mass). Even in the most demanding case, i.e., when the chemical potential falls between the zeroth and the first Landau levels, the cyclotron mass formula gives results accurate to better than 1%. The connection between the Hall conductivity and the viscosity provides a possible avenue to measure the Hall viscosity in graphene.

  5. Viscosity Approximation Methods for Two Accretive Operators in Banach Spaces

    Directory of Open Access Journals (Sweden)

    Jun-Min Chen

    2013-01-01

    Full Text Available We introduced a viscosity iterative scheme for approximating the common zero of two accretive operators in a strictly convex Banach space which has a uniformly Gâteaux differentiable norm. Some strong convergence theorems are proved, which improve and extend the results of Ceng et al. (2009 and some others.

  6. Relook on fitting of viscosity with undercooling of glassy liquids

    Indian Academy of Sciences (India)

    C Chattopadhyay; S Sangal; K Mondal

    2014-02-01

    The present approach is on the modification of viscosity fitting of undercooled liquid as a function of undercooling. The method consists of finding analytical solution of three arbitrary constants of the Vogel–Fulcher–Tamman (VFT) equation by choosing three viscosity data at three critical temperatures for an undercooled liquid. Three critical temperatures are liquidus temperature (l), crystallization onset temperature (x) and glass transition temperature (g). The experimental viscosity data at or very near to these three critical temperatures (depending on the availability in literature) have been utilized to achieve the analytical solution. The analytical solution of VFT equation is further examined by selecting the experimental data points away from the critical temperatures in order to check their (l, x and g) significance towards the solution. Total absolute error (TAE) and total squared error (TSE) values obtained from the present method with respect to the experimental viscosity data in the temperature range between l and g are very much comparable and in most of the cases lower than that of existing `best-fit' cited in the literature for a number of glassy alloys. Moreover, this method interestingly enables us to find the fragility parameters for a number of glassy alloys and convincingly explain their true glass forming abilities (GFA).

  7. Highly Branched Polyethylenes as Lubricant Viscosity and Friction Modifiers

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Joshua W.; Zhou, Yan; Qu, Jun; Bays, John T.; Cosimbescu, Lelia

    2016-10-08

    A series of highly branched polyethylenes (BPE) were prepared and used in a Group I base oil as potential viscosity and friction modifiers. The lubricating performance of these BPEs supports the expected dual functionality. Changes in polarity, topology, and molecular weight of the BPEs showed significant effects on the lubricants’ performance, which provide scientific insights for polymer design in future lubricant development.

  8. PVT characterization and viscosity modeling and prediction of crude oils

    DEFF Research Database (Denmark)

    Cisneros, Eduardo Salvador P.; Dalberg, Anders; Stenby, Erling Halfdan

    2004-01-01

    In previous works, the general, one-parameter friction theory (f-theory), models have been applied to the accurate viscosity modeling of reservoir fluids. As a base, the f-theory approach requires a compositional characterization procedure for the application of an equation of state (EOS), in mos...

  9. Glass viscosity calculation based on a global statistical modelling approach

    Energy Technology Data Exchange (ETDEWEB)

    Fluegel, Alex

    2007-02-01

    A global statistical glass viscosity model was developed for predicting the complete viscosity curve, based on more than 2200 composition-property data of silicate glasses from the scientific literature, including soda-lime-silica container and float glasses, TV panel glasses, borosilicate fiber wool and E type glasses, low expansion borosilicate glasses, glasses for nuclear waste vitrification, lead crystal glasses, binary alkali silicates, and various further compositions from over half a century. It is shown that within a measurement series from a specific laboratory the reported viscosity values are often over-estimated at higher temperatures due to alkali and boron oxide evaporation during the measurement and glass preparation, including data by Lakatos et al. (1972) and the recently published High temperature glass melt property database for process modeling by Seward et al. (2005). Similarly, in the glass transition range many experimental data of borosilicate glasses are reported too high due to phase separation effects. The developed global model corrects those errors. The model standard error was 9-17°C, with R^2 = 0.985-0.989. The prediction 95% confidence interval for glass in mass production largely depends on the glass composition of interest, the composition uncertainty, and the viscosity level. New insights in the mixed-alkali effect are provided.

  10. Viscosity solutions of fully nonlinear functional parabolic PDE

    Directory of Open Access Journals (Sweden)

    Liu Wei-an

    2005-01-01

    Full Text Available By the technique of coupled solutions, the notion of viscosity solutions is extended to fully nonlinear retarded parabolic equations. Such equations involve many models arising from optimal control theory, economy and finance, biology, and so forth. The comparison principle is shown. Then the existence and uniqueness are established by the fixed point theory.

  11. Quantitatively Mapping Cellular Viscosity with Detailed Organelle Information via a Designed PET Fluorescent Probe

    Science.gov (United States)

    Liu, Tianyu; Liu, Xiaogang; Spring, David R.; Qian, Xuhong; Cui, Jingnan; Xu, Zhaochao

    2014-06-01

    Viscosity is a fundamental physical parameter that influences diffusion in biological processes. The distribution of intracellular viscosity is highly heterogeneous, and it is challenging to obtain a full map of cellular viscosity with detailed organelle information. In this work, we report 1 as the first fluorescent viscosity probe which is able to quantitatively map cellular viscosity with detailed organelle information based on the PET mechanism. This probe exhibited a significant ratiometric fluorescence intensity enhancement as solvent viscosity increases. The emission intensity increase was attributed to combined effects of the inhibition of PET due to restricted conformational access (favorable for FRET, but not for PET), and the decreased PET efficiency caused by viscosity-dependent twisted intramolecular charge transfer (TICT). A full map of subcellular viscosity was successfully constructed via fluorescent ratiometric detection and fluorescence lifetime imaging; it was found that lysosomal regions in a cell possess the highest viscosity, followed by mitochondrial regions.

  12. A new reference viscosity model for hydrogen sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, K.A.G. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering, Electrical and Computer Engineering Research Facility; Quinones-Cisneros, S.E. [Univ. Nacional Autonoma de Mexico, Mexico City (Mexico). Dept. of Rheology, Materials Research Inst.; Giri, B.R.; Blais, P.; Marriott, R.A. [Alberta Sulphur Research Ltd., Calgary, AB (Canada); Calgary Univ., AB (Canada). Dept. of Chemistry

    2010-07-01

    New and economical ways of reducing emissions of acid gases to the atmosphere are becoming increasingly important in the petroleum industry. This presentation discussed the promising sequestration option of injecting these acid gases into formations for disposal and or storage. Acid gas injection (AGI) is a commonly used process for the disposal of mixtures of hydrogen sulphide and carbon dioxide, particularly in small scale schemes. The acid gas is sometimes used as a miscible flood fluid for pressure maintenance. The use of AGI is being considered for the production of elemental sulphur. Accurate viscosities are needed in the design of these injection schemes to determine pressure drops due to fluid flow in both the acid gas pipeline and the injection well. This presentation included experimental data and discussed the applicability of the friction theory for viscosity modelling to reproduce the existing experimental visco cities of hydrogen sulphide and its mixtures. The friction theory model was shown to be a highly flexible and powerful tool for the modelling the viscosity of reservoir fluids, from light to heavy fluids under broad conditions of temperature, pressure and composition. During the development of this reference viscosity model, a literature review identified areas where additional data is needed to fill voids and resolve discrepancies of existing data sets. It was concluded that although the developed model was based on limited data, the sound physical reasoning provided good results. An experimental program has been launched to determine the viscosities of hydrogen sulphide (H{sub 2}S) in the critical areas identified in the initial reference model. The current update to the data set consists of experimental H{sub 2}S viscosities up to 1000 bar and at temperatures between 0 and 150 degrees C. The data will be applied to update the H{sub 2}S reference viscosity model based on the friction-theory. The updated reference equation will help improve

  13. Research on viscosity of metal at high pressure

    Science.gov (United States)

    Li, Y.; Liu, F.; Ma, X.; Zhang, M.

    2016-11-01

    A new experimental technique, the flyer-impact method, is proposed in this article to investigate the viscosity coefficient of shocked metals. In this technique, a shock wave with a sinusoidal perturbation on the front is induced by the sinusoidal profile of the impact surface of the sample by use of a two-stage light-gas gun, and the oscillatory damping process of the perturbation amplitude is monitored by electric pins. The damping processes of aluminum at 78 and 101 GPa and iron at 159 and 103 GPa are obtained by this technique, which supplement the existing data by measuring the viscosity coefficient via a dynamic high-pressure method. Applying the formula of Miller and Ahrens to fit the experimental data, the shear viscosity coefficients of aluminum at 78 and 101 GPa are 1350 ± 500 and 1200 ± 500 Pa s, respectively, and those of iron at 159 and 103 GPa are 1150 ± 1000 and 4800 ± 1000 Pa s, respectively. The values measured by the flyer-impact method, approximately 103 Pa s, are consistent with those measured by Sakharov's method, while still greatly differing from those measured by static high-pressure methods. In dynamic high-pressure experiments, the shear viscosity is related to dislocation motion in the solid material, while that in static high-pressure experiments is related to the diffusion motion of atoms or molecules in liquids. Therefore, there are different physical meanings of shear viscosity in dynamic and static high-pressure experiments, and there is no comparability among these results.

  14. Intermolecular potential parameters and combining rules determined from viscosity data

    Energy Technology Data Exchange (ETDEWEB)

    Bastien, Lucas A.J.; Price, Phillip N.; Brown, Nancy J.

    2010-05-07

    The Law of Corresponding States has been demonstrated for a number of pure substances and binary mixtures, and provides evidence that the transport properties viscosity and diffusion can be determined from a molecular shape function, often taken to be a Lennard-Jones 12-6 potential, that requires two scaling parameters: a well depth {var_epsilon}{sub ij} and a collision diameter {sigma}{sub ij}, both of which depend on the interacting species i and j. We obtain estimates for {var_epsilon}{sub ij} and {sigma}{sub ij} of interacting species by finding the values that provide the best fit to viscosity data for binary mixtures, and compare these to calculated parameters using several 'combining rules' that have been suggested for determining parameter values for binary collisions from parameter values that describe collisions of like molecules. Different combining rules give different values for {sigma}{sub ij} and {var_epsilon}{sub ij} and for some mixtures the differences between these values and the best-fit parameter values are rather large. There is a curve in ({var_epsilon}{sub ij}, {sigma}{sub ij}) space such that parameter values on the curve generate a calculated viscosity in good agreement with measurements for a pure gas or a binary mixture. The various combining rules produce couples of parameters {var_epsilon}{sub ij}, {sigma}{sub ij} that lie close to the curve and therefore generate predicted mixture viscosities in satisfactory agreement with experiment. Although the combining rules were found to underpredict the viscosity in most of the cases, Kong's rule was found to work better than the others, but none of the combining rules consistently yields parameter values near the best-fit values, suggesting that improved rules could be developed.

  15. Simultaneous liquid viscosity and density determination with piezoelectric unimorph cantilevers

    Science.gov (United States)

    Shih, Wan Y.; Li, Xiaoping; Gu, Huiming; Shih, Wei-Heng; Aksay, Ilhan A.

    2001-01-01

    We have examined both experimentally and theoretically a piezoelectric unimorph cantilever as a liquid viscosity-and-density sensor. The fabricated piezoelectric unimorph consisted of a PbOṡZrO2ṡTiO2 (PZT) layer on a thin stainless-steel plate. In addition to a driving electrode, a sensing electrode was placed on top of the PZT layer, permitting the direct measurement of the resonance frequency. The cantilever was tested using water-glycerol solutions of different compositions. In all three of the tested modes, the resonance frequency decreased while the width of the resonance peak increased with increasing glycerol content. To account for the liquid effect, we consider the cantilever as a sphere of radius R oscillating in a liquid. By including the high and low frequency terms in the induced mass and the damping coefficient of the liquid, we show that for a given liquid density and viscosity the oscillating-sphere model predicts a resonance frequency and peak width that closely agree with experiment. Furthermore, the viscosity and the density of a liquid have been determined simultaneously using the experimentally measured resonance frequency and peak width as inputs to the oscillating-sphere model. The calculated liquid viscosity and density closely agreed with the known values, indicating that our cantilever-based sensor is effective in determining viscosity and density, simultaneously. We also show that scaling analysis predicts an increase in the width of the resonance peak with decreasing cantilever size, an observation in agreement with the large peak widths observed for microcantilevers.

  16. Viscosity of aqueous and cyanate ester suspensions containing alumina nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Lawler, Katherine [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    The viscosities of both aqueous and cyanate ester monomer (BECy) based suspensions of alumina nanoparticle were studied. The applications for these suspensions are different: aqueous suspensions of alumina nanoparticles are used in the production of technical ceramics made by slip casting or tape casting, and the BECy based suspensions are being developed for use in an injection-type composite repair resin. In the case of aqueous suspensions, it is advantageous to achieve a high solids content with low viscosity in order to produce a high quality product. The addition of a dispersant is useful so that higher solids content suspensions can be used with lower viscosities. For BECy suspensions, the addition of nanoparticles to the BECy resin is expected to enhance the mechanical properties of the cured composite. The addition of saccharides to aqueous suspensions leads to viscosity reduction. Through DSC measurements it was found that the saccharide molecules formed a solution with water and this resulted in lowering the melting temperature of the free water according to classic freezing point depression. Saccharides also lowered the melting temperature of the bound water, but this followed a different rule. The shear thinning and melting behaviors of the suspensions were used to develop a model based on fractal-type agglomeration. It is believed that the structure of the particle flocs in these suspensions changes with the addition of saccharides which leads to the resultant viscosity decrease. The viscosity of the BECy suspensions increased with solids content, and the viscosity increase was greater than predicted by the classical Einstein equation for dilute suspensions. Instead, the Mooney equation fits the viscosity behavior well from 0-20 vol% solids. The viscosity reduction achieved at high particle loadings by the addition of benzoic acid was also investigated by NMR. It appears that the benzoic acid interacts with the surface of the alumina particle which may

  17. Blood Clots

    Science.gov (United States)

    ... or prevent blood clots from dissolving properly. Risk factors for excessive blood clotting include Certain genetic disorders Atherosclerosis Diabetes Atrial fibrillation Overweight, obesity, and metabolic syndrome Some medicines Smoking deep vein ...

  18. Blood Transfusion

    Science.gov (United States)

    ... to their work or home. The availability of plastic bags that can have one or more satellite bags ... in preparing the donated blood. The use of plastic bags allows the blood center to make a variety ...

  19. Dual Role of Viscosity During Start-Up of a Maxwell Fluid in a Pipe

    Institute of Scientific and Technical Information of China (English)

    任玲; 朱克勤

    2004-01-01

    Based on the exact solution of start-up flow of Maxwell fluids in a long circular straight pipe, the effect of viscosity on the time of flow establishment is analysed. It is found that the viscosity of Maxwell fluids plays a dual role.A key parameter is the dimensionless relaxation time λ-. For 0 <λ-< 0.0432, the viscosity mainly plays the same role as in Newtonian fluids, and the time of flow establishment decreases with the increasing viscosity; for λ- > 0.0432, the viscosity mainly plays a role of strengthening the oscillation, and the time of flow establishment increases with the incremental viscosity.

  20. Modelling droplet collision outcomes for different substances and viscosities

    Science.gov (United States)

    Sommerfeld, Martin; Kuschel, Matthias

    2016-12-01

    The main objective of the present study is the derivation of models describing the outcome of binary droplet collisions for a wide range of dynamic viscosities in the well-known collision maps (i.e. normalised lateral droplet displacement at collision, called impact parameter, versus collision Weber number). Previous studies by Kuschel and Sommerfeld (Exp Fluids 54:1440, 2013) for different solution droplets having a range of solids contents and hence dynamic viscosities (here between 1 and 60 mPa s) revealed that the locations of the triple point (i.e. coincidence of bouncing, stretching separation and coalescence) and the critical Weber number (i.e. condition for the transition from coalescence to separation for head-on collisions) show a clear dependence on dynamic viscosity. In order to extend these findings also to pure liquids and to provide a broader data basis for modelling the viscosity effect, additional binary collision experiments were conducted for different alcohols (viscosity range 1.2-15.9 mPa s) and the FVA1 reference oil at different temperatures (viscosity range 3.0-28.2 mPa s). The droplet size for the series of alcohols was around 365 and 385 µm for the FVA1 reference oil, in each case with fixed diameter ratio at Δ= 1. The relative velocity between the droplets was varied in the range 0.5-3.5 m/s, yielding maximum Weber numbers of around 180. Individual binary droplet collisions with defined conditions were generated by two droplet chains each produced by vibrating orifice droplet generators. For recording droplet motion and the binary collision process with good spatial and temporal resolution high-speed shadow imaging was employed. The results for varied relative velocity and impact angle were assembled in impact parameter-Weber number maps. With increasing dynamic viscosity a characteristic displacement of the regimes for the different collision scenarios was also observed for pure liquids similar to that observed for solutions. This

  1. A Mathematical Study on Three Layered Oscillatory Blood Flow Through Stenosed Arteries

    Institute of Scientific and Technical Information of China (English)

    Dharmendra Tripathi

    2012-01-01

    A mathematical model is constructed to examine the characteristics of three layered blood flow through the oscillatory cylindrical tube (stenosed arteries).The proposed model basically consists three layers of blood (viscous fluids with different viscosities) named as core layer (red blood cells),intermediate layer (platelets/white blood cells) and peripheral layer (plasma).The analysis was restricted to propagation of small-amplitude harmonic waves,generated due to blood flow whose wave length is larger compared to the radius of the arterial segment.The impacts of viscosity of fluid in peripheral layer and intermediate layer on the interfaces,average flow rate,mechanical efficiency,trapping and reflux are discussed with the help of numerical and computational results.This model is the generalized form of the preceding models.On the basis of present discussion,it is found that the size of intermediate and peripheral layers reduces in expanded region and enhances in contracted region with the increasing viscosity of fluid in peripheral layer,whereas,opposite effect is observed for viscosity of fluid in intermediate layer.Final conclusion is that the average flow rate and mechanical efficiency increase with the increasing viscosity of fluid in both layers,however,the effects of the viscosity of fluid in both layers on trapping and reflux are opposite to each other.

  2. Blood Facts and Statistics

    Science.gov (United States)

    ... Facts and Statistics Printable Version Blood Facts and Statistics Facts about blood needs Facts about the blood ... to Top Learn About Blood Blood Facts and Statistics Blood Components Whole Blood and Red Blood Cells ...

  3. Effect of simvastatin combined amlodipine besylate on blood rheology and platelet activation in elderly patients with hypertension complicated with hyperlipemia

    Institute of Scientific and Technical Information of China (English)

    Ming-Zheng Jiang; Li Qiong; Hui Liu

    2016-01-01

    Objective:To investigate the effect of simvastatin combined amlodipine besylate on blood rheology and platelet activation in elderly patients with hypertension complicated with hyperlipemia.Methods: A total of 200 elderly patients with hypertension complicated with hyperlipemia were divided into hypertension group (n=64), hyperlipemia group (n=71) and combined (hypertension complicated with hyperlipemia) group (n=65). And alternate period health check-up 100 cases were selected as control group. The hypertension group was treated with amlodipine besylate monotherapy, hyperlipidemia group with simvastatin monotherapy, combined group received simvastatin combined with amlodipine besylate treatment, patients of three groups were treated for 12 weeks. Blood rheology and platelet activation before and after treatment were compared.Results: After treatment, blood pressure was significantly lower than that before treatment in hypertension and combined group (P<0.05), and the combined group reduced more significantly (P<0.05), blood fat was significantly lower than that before treatment in hyperlipemia and combined group (P<0.05), and combined group reduced more significantly (P<0.05); Before treatment, indexes of blood rheology (high shear whole blood viscosity, low shear whole blood viscosity, plasma viscosity, fibrinogen and platelet activation index (CD62p and CD63) of three groups were significantly higher than those in control group (P<0.05), and the combined group was increased more significantly than hypertension and hyperlipidemia group (P<0.05); After treatment, blood rheology (high shear whole blood viscosity, low shear whole blood viscosity, plasma viscosity, fibrinogen) and platelet activation index (CD62p and CD63) of hyperlipidemia group and combined group were significantly lower than before treatment (P<0.05), and the reduction combined group were more significant in amplitude (P<0.05).Conclusions: Simvastatin combined amlodipine besylate therapy can

  4. Cord Blood

    Directory of Open Access Journals (Sweden)

    Saeed Abroun

    2014-05-01

    Full Text Available   Stem cells are naïve or master cells. This means they can transform into special 200 cell types as needed by body, and each of these cells has just one function. Stem cells are found in many parts of the human body, although some sources have richer concentrations than others. Some excellent sources of stem cells, such as bone marrow, peripheral blood, cord blood, other tissue stem cells and human embryos, which last one are controversial and their use can be illegal in some countries. Cord blood is a sample of blood taken from a newborn baby's umbilical cord. It is a rich source of stem cells, umbilical cord blood and tissue are collected from material that normally has no use following a child’s birth. Umbilical cord blood and tissue cells are rich sources of stem cells, which have been used in the treatment of over 80 diseases including leukemia, lymphoma and anemia as bone marrow stem cell potency.  The most common disease category has been leukemia. The next largest group is inherited diseases. Patients with lymphoma, myelodysplasia and severe aplastic anemia have also been successfully transplanted with cord blood. Cord blood is obtained by syringing out the placenta through the umbilical cord at the time of childbirth, after the cord has been detached from the newborn. Collecting stem cells from umbilical blood and tissue is ethical, pain-free, safe and simple. When they are needed to treat your child later in life, there will be no rejection or incompatibility issues, as the procedure will be using their own cells. In contrast, stem cells from donors do have these potential problems. By consider about cord blood potency, cord blood banks (familial or public were established. In IRAN, four cord blood banks has activity, Shariati BMT center cord blood bank, Royan familial cord blood banks, Royan public cord blood banks and Iranian Blood Transfusion Organ cord blood banks. Despite 50,000 sample which storage in these banks, but the

  5. On the viscosity of magnetic fluid with low and moderate solid fraction

    Institute of Scientific and Technical Information of China (English)

    Zhiqiang Ren; Yanping Han; Ruoyu Hong; Jianmin Ding; Hongzhong Li

    2008-01-01

    The design of a pressurized capillary rheometer operating at prescribed temperature is described to measure the viscosity of magnetic fluids (MFs) containing Fe3O4 magnetic nanoparticles (MNPs). The equipment constant of the rheometer was obtained using liquids with predetermined viscosities. Experimentally measured viscosities were used to evaluate different equations for suspension viscosities. Deviation of measured suspension viscosities from the Einstein equation was found to be basically due to the influence of spatial distribution and aggregation of Fe3O4 MNPs. By taking account of the coating layer on MNPs and the aggregation of MNPs in MFs, a modified Einstein equation was proposed to fit the experimental data. Moreover, the influence of external magnetic field on viscosity was also taken into account. Viscosities thus predicted are in good agreement with experimental data. Temperature effect on suspension viscosity was shown experimentally to be due to the shear-thinning behavior of the MFs.

  6. Viscosity of egg white from hens of different strains fed with commercial and natural additives

    Directory of Open Access Journals (Sweden)

    Fernanda Papa Spada

    2012-03-01

    Full Text Available Yolk color and egg white (albumen cleanliness and viscosity are important parameters by which consumers judge the quality of eggs. This study aimed to investigate changes in albumen viscosity during storage of eggs for up to 36 days from two different commercial laying hen strains (Carijo Barbada and Isa Brown fed a diet containing annatto (1.5 and 2.0% or a synthetic additive without synthetic colorants (control. Analyses of humidity, albumen height, pH, viscosity, foam formation, and stability were carried out on eggs. Carijo Barbada strain had smaller albumen, lower humidity and higher egg white viscosity than Isa Brown strain; however, with storage, viscosity lowered significantly on both strains. Initially, the addition of 2.0% of annatto or a synthetic additive increased viscosity in both strains, but with storage only the control maintained longer viscosity. Lower viscosity did not change foam density and stability.

  7. Solvent viscosity dependence of the folding rate of a small protein: distributed computing study.

    Science.gov (United States)

    Zagrovic, Bojan; Pande, Vijay

    2003-09-01

    By using distributed computing techniques and a supercluster of more than 20,000 processors we simulated folding of a 20-residue Trp Cage miniprotein in atomistic detail with implicit GB/SA solvent at a variety of solvent viscosities (gamma). This allowed us to analyze the dependence of folding rates on viscosity. In particular, we focused on the low-viscosity regime (values below the viscosity of water). In accordance with Kramers' theory, we observe approximately linear dependence of the folding rate on 1/gamma for values from 1-10(-1)x that of water viscosity. However, for the regime between 10(-4)-10(-1)x that of water viscosity we observe power-law dependence of the form k approximately gamma(-1/5). These results suggest that estimating folding rates from molecular simulations run at low viscosity under the assumption of linear dependence of rate on inverse viscosity may lead to erroneous results.

  8. Some remarks on singular solutions of nonlinear elliptic equations. III: viscosity solutions, including parabolic operators

    CERN Document Server

    Caffarelli, Luis; Nirenberg, Louis

    2011-01-01

    The paper concerns singular solutions of nonlinear elliptic equations, which include removable singularities for viscosity solutions, a strengthening of the Hopf Lemma including parabolic equations, Strong maximum principle and Hopf Lemma for viscosity solutions including also parabolic equations.

  9. Decay estimate of viscosity solutions of nonlinear parabolic PDEs and applications

    Directory of Open Access Journals (Sweden)

    Silvana Marchi

    2014-05-01

    Full Text Available The aim of this paper is to establish a decay estimate for viscosity solutions of nonlinear PDEs. As an application we prove existence and uniqueness for time almost periodic viscosity solutions.

  10. Area evolution, bulk viscosity and entropy principles for dynamical horizons

    CERN Document Server

    Gourgoulhon, E; Gourgoulhon, Eric; Jaramillo, Jose Luis

    2006-01-01

    We derive from Einstein equation an evolution law for the area of a trapping or dynamical horizon. The solutions to this differential equation show a causal behavior. Moreover, in a viscous fluid analogy, the equation can be interpreted as an energy balance law, yielding to a positive bulk viscosity. These two features contrast with the event horizon case, where the non-causal evolution of the area and the negative bulk viscosity require teleological boundary conditions. This reflects the local character of trapping horizons as opposed to event horizons. Interpreting the area as the entropy, we propose to use an area/entropy evolution principle to select a unique dynamical horizon and time slicing in the Cauchy evolution of an initial marginally trapped surface.

  11. Hot-Wire Method for Kinematic Viscosity Estimation

    Science.gov (United States)

    Giaretto, Valter

    2010-03-01

    This paper explores the characterization of thermal and momentum diffusion properties of condensed phase biological fluids. The widely used transient hot-wire technique for determination of thermal diffusion properties is proposed here to investigate also the apparent kinematic viscosity of fluids with the apparatus commonly adopted for thermal conductivity and/or thermal diffusivity determination. The undesired onset of convection in the determination of thermal diffusion properties is in this case the useful effect measured at the wire-fluid interface. From a theoretical point of view, the onset of convection time at a given vertical position along the wire has been related to the Prandtl number, and the reliability of the kinematic viscosity has been studied and preliminarily tested in the case of water.

  12. Phantom dark energy as an effect of bulk viscosity

    CERN Document Server

    Velten, Hermano; Meng, Xinhe

    2013-01-01

    In a homogeneous and isotropic universe bulk viscosity is the unique viscous effect capable to modify the background dynamics. Effects like shear viscosity or heat conduction can only change the evolution of the perturbations. The existence of a bulk viscous pressure in a fluid, which in order to obey to the second law of thermodynamics is negative, reduces its effective pressure. We discuss in this study the degeneracy in bulk viscous cosmologies and address the possibility that phantom dark energy cosmology could be caused by the existence of non-equilibrium pressure in any cosmic component. We establish the conditions under which either matter or radiation viscous cosmologies can be mapped into the phantom dark energy scenario with constraints from multiple observational data-sets

  13. Probing the shear viscosity of an active nematic film

    Science.gov (United States)

    Guillamat, Pau; Ignés-Mullol, Jordi; Shankar, Suraj; Marchetti, M. Cristina; Sagués, Francesc

    2016-12-01

    In vitro reconstituted active systems, such as the adenosine triphosphate (ATP)-driven microtubule bundle suspension developed by the Dogic group [T. Sanchez, D. T. Chen, S. J. DeCamp, M. Heymann, and Z. Dogic, Nature (London) 491, 431 (2012), 10.1038/nature11591], provide a fertile testing ground for elucidating the phenomenology of active liquid crystalline states. Controlling such novel phases of matter crucially depends on our knowledge of their material and physical properties. In this Rapid Communication, we show that the shear viscosity of an active nematic film can be probed by varying its hydrodynamic coupling to a bounding oil layer. Using the motion of disclinations as intrinsic tracers of the flow field and a hydrodynamic model, we obtain an estimate for the shear viscosity of the nematic film. Knowing this now provides us with an additional handle for robust and precision tunable control of the emergent dynamics of active fluids.

  14. Gas distribution effects on waste properties: Viscosities of bubbly slurries

    Energy Technology Data Exchange (ETDEWEB)

    Gauglitz, P.A.; Shah, R.R.; Davis, R.L.

    1994-09-01

    The retention and episodic release of flammable gases are critical safety concerns for double-shell tanks that contain waste slurries. The rheological behavior of the waste, particularly of the settled sludge, is critical to characterizing the tendency of the waste to retain gas bubbles. The presence of gas bubbles is expected to affect the rheology of the sludge, but essentially no literature data are available to assess the effect of bubbles. Accordingly, the objectives of this study are to develop models for the effect of gas bubbles on the viscosity of a particulate slurry, develop an experimental method (capillary rheometer), collect data on the viscosity of a bubbly slurry, and develop a theoretical basis for interpreting the experimental data from the capillary rheometer.

  15. Effects of Liquid Second Viscosity in High-Amplitude Sonoluminescence

    Institute of Scientific and Technical Information of China (English)

    Ahmad Moshaii; Rasool Sadighi-Bonabi; Mohammad Taeibi-Rahni; Mehdi Daemi

    2004-01-01

    @@ The well-known Rayleigh-Plesset (RP) equation is the base of nearly all hydrodynamical descriptions of the sonoluminescence phenomenon. A major deficiency of this equation is that it accounts for viscosity of an incompressible liquid and compressibility, separately. By removing this approximation, we have modified the RP equation, considering effects of liquid second viscosity. This modification exhibits its importance at the end of an intense collapse, so that the new model predicts the appearance of a new picosecond bouncing during highamplitude sonoluminescence radiation. This new bouncing produces very sharp (sub-picosecond) peaks on the top of the sonoluminescence pulse. These new behaviours are more remarkable for higher driving pressures and lower ambient temperatures.

  16. The collective mode and turbulent viscosity in accretion discs

    Energy Technology Data Exchange (ETDEWEB)

    Fridman, A.M.; Boyarchuk, A.A.; Bisikalo, D.V.; Kuznetsov, O.A.; Khoruzhii, O.V.; Torgashin, Yu.M.; Kilpio, A.A

    2003-10-20

    The existence of a spiral-vortex structure is revealed by a numerical simulation of the dynamics of an accretion disc in close binary stars. This structure is not related to the tidal influence of a companion star. It is a density wave containing a one-armed spiral and an anticyclonic vortex. The formation of the structure is caused by a hydrodynamical instability. The latter results in a disc turbulence with a turbulent viscosity coefficient {nu}{approx_equal}0.035 {omega}h{sup 2} (h is a semithickness of the disc). This value is in accordance with both the value of a numerical viscosity in presented calculations and the results of observations. The period of the density wave rotation is in agreement with the typical periods of light curve variations observed in cataclysmic binary stars.

  17. Accretion disc viscosity: a limit on the anisotropy

    CERN Document Server

    Nixon, Chris

    2015-01-01

    Observations of warped discs can give insight into the nature of angular momentum transport in accretion discs. Only a few objects are known to show strong periodicity on long timescales, but when such periodicity is present it is often attributed to precession of the accretion disc. The X-ray binary Hercules X-1/HZ Herculis (Her X-1) is one of the best examples of such periodicity and has been linked to disc precession since it was first observed. By using the current best-fitting models to Her X-1, which invoke precession driven by radiation warping, I place a constraint on the effective viscosities that act in a warped disc. These effective viscosities almost certainly arise due to turbulence induced by the magneto-rotational instability. The constraints derived here are in agreement with analytical and numerical investigations into the nature of magneto-hydrodynamic disc turbulence, but at odds with some recent global simulations.

  18. An estimate of the bulk viscosity of the hadronic medium

    CERN Document Server

    Sarwar, Golam; Alam, Jan-e

    2015-01-01

    The bulk viscosity of the hadronic medium within the ambit of the Hadron Resonance Gas (HRG) model approach including the Hagedorn density of states has been estimated. The HRG thermodynamics within a grand canonical ensemble provides the mean hadron number as well as its fluctuation. The fluctuation in the chemical composition of the hadronic medium in the grand canonical ensemble can result in non-zero divergence of the hadronic fluid flow velocity, allowing us to estimate the hadronic bulk viscosity $\\zeta$ upto a relaxation time. We study the influence of the hadronic spectrum on $\\zeta$ and find its correlation with the conformal symmetry breaking (CSB) measure, $\\epsilon-3P$. We estimate $\\zeta$ along the chemical freezeout curve and find that at FAIR energies $\\zeta/s$ can be enhanced by a factor of five as compared to LHC energies.

  19. Magnetically-charged black branes and viscosity/entropy ratios

    Science.gov (United States)

    Liu, Hai-Shan; Lü, H.; Pope, C. N.

    2016-12-01

    We consider asymptotically-AdS n-dimensional black brane solutions in a theory of gravity coupled to a set of N p-form field strengths, in which the field strengths carry magnetic charges. For appropriately chosen charges, the metrics are isotropic in the ( n - 2) transverse directions. However, in general the field strength configurations break the full Euclidean symmetry of the ( n - 2)-dimensional transverse space, and the shear viscosity tensor in the dual theory is no longer isotropic. We study the linearised equations for transverse traceless metric perturbations in these backgrounds, and by employing the Kubo formula we obtain expressions for the ratios η/S of the shear viscosity components divided by the entropy density. We find that the KSS bound on the ratios η/S is generally violated in these solutions. We also extend the discussion by including a dilatonic scalar field in the theory, leading to solutions that are asymptotically Lifshitz with hyperscaling violation.

  20. Black Brane Viscosity and the Gregory-Laflamme Instability

    CERN Document Server

    Camps, Joan; Haddad, Nidal

    2010-01-01

    We study long wavelength perturbations of neutral black p-branes in asymptotically flat space and show that, as anticipated in the blackfold approach, solutions of the relativistic hydrodynamic equations for an effective p+1-dimensional fluid yield solutions to the vacuum Einstein equations in a derivative expansion. Going beyond the perfect fluid approximation, we compute the effective shear and bulk viscosities of the black brane. The values we obtain saturate generic bounds. Sound waves in the effective fluid are unstable, and have been previously related to the Gregory-Laflamme instability of black p-branes. By including the damping effect of the viscosity in the unstable sound waves, we obtain a remarkably good and simple approximation to the dispersion relation of the Gregory-Laflamme modes, whose accuracy increases with the number of transverse dimensions. We propose an exact limiting form as the number of dimensions tends to infinity.

  1. Hubble Parameter in QCD Universe for finite Bulk Viscosity

    CERN Document Server

    Tawfik, A; Mansour, H; Harko, T

    2010-01-01

    The influence of perturbative bulk viscosity on the evolution of Hubble parameter in the QCD era of the early Universe has been analyzed, where Friedmann-Robertson-Walker metric and Einstein field equations are utilized. Homogeneous and isotropic background matter is assumed to be characterized by barotropic equations of state deduced from recent lattice QCD simulations and heavy--ion collisions. Taking into account perturbative bulk viscosity coefficient, an estimation for the evolution of the Hubble parameter has been introduced and compared with its evolution in a non--viscous matter. A numerical solution for finite viscous Israel-Stewart background matter is also worked out. Both methods qualitatively agree in reproducing viscous Hubble parameter that turns to be slightly different from the non--viscous one. This treatment is strictly limited within a very narrow temperature-- or time--interval in QCD era, where the QGP matter is likely dominant.

  2. Dissipative Processes in the Early Universe: Bulk Viscosity

    CERN Document Server

    Tawfik, A; Mansour, H; Wahba, M

    2009-01-01

    In this talk, we discuss one of the dissipative processes which likely take place in the Early Universe. We assume that the matter filling the isotropic and homogeneous background is to be described by a relativistic viscous fluid characterized by an ultra-relativistic equation of state and finite bulk viscosity deduced from recent lattice QCD calculations and heavy-ion collisions experiments. We concentrate our treatment to bulk viscosity as one of the essential dissipative processes in the rapidly expanding Early Universe and deduce the dependence of the scale factor and Hubble parameter on the comoving time $t$. We find that both scale factor and Hubble parameter are finite at $t=0$, revering to absence of singularity. We also find that their evolution apparently differs from the one resulting in when assuming that the background matter is an ideal and non-viscous fluid.

  3. Holographic Shear Viscosity in Hyperscaling Violating Theories without Translational Invariance

    CERN Document Server

    Ling, Yi; Zhou, Zhenhua

    2016-01-01

    In this paper we investigate the ratio of shear viscosity to entropy density, $\\eta/s$, in hyperscaling violating geometry with lattice structure. We show that the scaling relation with hyperscaling violation gives a strong constraint to the mass of graviton and usually leads to a power law of temperature, $\\eta/s\\sim T^\\kappa$. Remarkably, we find the exponent $\\kappa$ can be greater than two such that the new bound for viscosity raised in arXiv:1601.02757 is violated. Our above observation is testified by constructing specific solutions with UV completion in various holographic models. Finally, we compare the boundedness of $\\kappa$ with the behavior of entanglement entropy and conjecture a relation between them.

  4. Dark matter perturbations and viscosity: a causal approach

    CERN Document Server

    Acquaviva, Giovanni; Pénin, Aurélie

    2016-01-01

    The inclusion of dissipative effects in cosmic fluids modifies their clustering properties and could have observable effects on the formation of large scale structures. We analyse the evolution of density perturbations of cold dark matter endowed with causal bulk viscosity. The perturbative analysis is carried out in the Newtonian approximation and the bulk viscosity is described by the causal Israel-Stewart (IS) theory. In contrast to the non-causal Eckart theory, we obtain a third order evolution equation for the density contrast that depends on three free parameters. For certain parameter values, the density contrast and growth factor in IS mimic their behaviour in $\\Lambda$CDM when $z \\geq 1$. Interestingly, and contrary to intuition, certain sets of parameters lead to an increase of the clustering.

  5. The Shear Viscosity in an Anisotropic Unitary Fermi Gas

    CERN Document Server

    Samanta, Rickmoy; Trivedi, Sandip P

    2016-01-01

    We consider a system consisting of a strongly interacting, ultracold unitary Fermi gas under harmonic confinement. Our analysis suggests the possibility of experimentally studying, in this system, an anisotropic shear viscosity tensor driven by the anisotropy in the trapping potential. In particular, we suggest that this experimental setup could mimic some features of anisotropic geometries that have recently been studied for strongly coupled field theories which have a gravitational dual. Results using the AdS/CFT correspondence in these theories show that in systems with a background linear potential, certain viscosity components can be made much smaller than the entropy density, parametrically violating the KSS bound. This intuition, along with results from a Boltzmann analysis that we perform, suggests that a violation of the KSS bound can perhaps occur in the unitary Fermi gas system when it is subjected to a suitable anisotropic trapping potential. We give a concrete proposal for an experimental setup w...

  6. Fission Dynamics: The Quest of a Temperature Dependent Nuclear Viscosity

    Directory of Open Access Journals (Sweden)

    E. Vardaci

    2013-08-01

    Full Text Available This paper presents a journey within some open questions about the current use of a temperature dependent nuclear viscosity in models of nuclear fission and proposes an alternative experimental approach by using systems of intermediate fissility. This study is particularly relevant because: i systems of intermediate fissility offer a suitable frame-work since the intervals between the compound nucleus and scission point temperatures with increasing excitation energy are much smaller than in the case of heavier systems, ii the dependence of viscosity on the temperature may change with the fissility of the composite system; iii the opportunity to measure also observables in the evaporation residues channel translates into a larger set of effective constraints for the models.

  7. CHARACTERISTICS OF BLOOD RHEOLOGICAL PARAMETERS IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE

    Directory of Open Access Journals (Sweden)

    M. M. Egorova

    2014-07-01

    Full Text Available Aim – to evaluate macro-and microrheology hemorheological characteristics parameters in patients with COPD, and their dependence on the severity of COPD.Materials and methods. The study included 107 people, 80 patients with chronic obstructive pulmonary disease I, II, III, IV degree and 27 persons as a control group. Rheological examination included determination of the viscosity of whole blood and erythrocyte suspensions with a hematocrit (HT 40 % in plasma and nonggregating environment, the plasma viscosity. Measuring the effectiveness of oxygen delivery to tissues produced by the formula: TO2 = Ht/η, where η — viscosity of blood. The degree of erythrocyte aggregation was evaluated by microscopy with video recording of diluted blood, and computer image analysis. Indices of rigidity of the red blood cells were calculated, indicators of internal viscosity of red blood cell content and efficiency of transport of oxygen to the tissues.Results. In patients with COPD were identified expressed disturbances of macro-and microrheology of blood parameters were identified. Blood viscosity at all shear stresses were increased by 23–27% compared with the control group, plasma viscosity – 21.5 % (p < 0.001. Indicators of hemoglobin and hematocrit (by 9.7 % and 8.8 % respectively, p < 0,001 were Significantly higher in patients with COPD. The viscosity of erythrocyte suspension to a standard hematocrit of 40 % in saline and in autologous plasma at different shear stresses were increased by 19,5–25,3 % (p < 0,001 and 22–24 % (p < 0,001, respectively. Revealed significant changes in properties of the blood stream, which in turn led to a marked reduction in oxygen-function of the blood in 27.5 % (p < 0.001.Conclusions. In patients with COPD, there are marked disturbances of macro-and microrheology of blood parameters, the viscosity of whole blood and plasma increases greatly, red blood cell deformability is reduced, and changing of the

  8. Gamma radiation effects on the viscosity of green banana flour

    Energy Technology Data Exchange (ETDEWEB)

    Uehara, Vanessa B.; Inamura, Patricia Y.; Mastro, Nelida L. Del [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], e-mail: vanessa.uehara@usp.br, e-mail: patyoko@yahoo.com, e-mail: nlmastro@ipen.br

    2009-07-01

    Banana (Musa sp) is a tropical fruits with great acceptability among consumers and produced in Brazil in a large scale. Bananas are not being as exploited as they could be in prepared food, and research could stimulate greater interest from industry. The viscosity characteristics and a product consistency can determine its acceptance by the consumer. Particularly the starch obtained from green banana had been studied from the nutritional point of view since the concept of Resistant Starch was introduced. Powder RS with high content of amylose was included in an approved food list with alleged functional properties in Brazilian legislation. Ionizing radiation can be used as a public health intervention measure for the control of food-borne diseases. Radiation is also a very convenient tool for polymer materials modification through degradation, grafting and crosslinking. In this work the influence of ionizing radiation on the rheological behavior of green banana pulp was investigated. Samples of green banana pulp flour were irradiated in a {sup 60}Co Gammacell 220 (AECL) with doses of 0 kGy,1 kGy, 3 kGy, 5 kGy and 10 kGy in glass recipients. After irradiation 3% and 5% aqueous dilution were prepared and viscosity measurements performed in a Brooksfield, model DVIII viscometer using spindle SC4-18 and SC4-31. There was a reduction of the initial viscosity of the samples as a consequence of radiation processing, being the reduction inversely proportional to the flour concentration. The polysaccharide content of the banana starch seems to be degraded by radiation in solid state as shown by the reduction of viscosity as a function of radiation dose. (author)

  9. Synthetic Organic Electrochemistry in Ionic Liquids: The Viscosity Question

    Directory of Open Access Journals (Sweden)

    Scott T. Handy

    2011-07-01

    Full Text Available Ionic liquids are obvious candidates for use in electrochemical applications due to their ionic character. Nevertheless, relatively little has been done to explore their application in electrosynthesis. We have studied the Shono oxidation of arylamines and carbamates using ionic liquids as recyclable solvents and have noted that the viscosity of the medium is a major problem, although with the addition of sufficient co-solvent, good results and excellent recovery and recycling of the ionic liquid can be achieved.

  10. Zero Viscosity Limit for Analytic Solutions of the Primitive Equations

    Science.gov (United States)

    Kukavica, Igor; Lombardo, Maria Carmela; Sammartino, Marco

    2016-10-01

    The aim of this paper is to prove that the solutions of the primitive equations converge, in the zero viscosity limit, to the solutions of the hydrostatic Euler equations. We construct the solution of the primitive equations through a matched asymptotic expansion involving the solution of the hydrostatic Euler equation and boundary layer correctors as the first order term, and an error that we show to be {O(√{ν})}. The main assumption is spatial analyticity of the initial datum.

  11. "Hall viscosity" and intrinsic metric of incompressible fractional Hall fluids

    OpenAIRE

    Haldane, F. D. M.

    2009-01-01

    The (guiding-center) "Hall viscosity" is a fundamental tensor property of incompressible ``Hall fluids'' exhibiting the fractional quantum Hall effect; it determines the stress induced by a non-uniform electric field, and the intrinsic dipole moment on (unreconstructed) edges. It is characterized by a rational number and an intrinsic metric tensor that defines distances on an ``incompressibility lengthscale''. These properties do not require rotational invariance in the 2D plane. The sign of ...

  12. Magnetic component of gluon plasma and its viscosity

    Energy Technology Data Exchange (ETDEWEB)

    Chernodub, M.N. [CNRS, Laboratoire de Mathematiques et Physique Theorique, Universite Francois-Rabelais Tours, Parc de Grandmont, 37200 Tours (France); Department of Physics and Astronomy, University of Gent, Krijgslaan 281, S9, B-9000 Gent (Belgium); Verschelde, H. [Department of Physics and Astronomy, University of Gent, Krijgslaan 281, S9, B-9000 Gent (Belgium); Zakharov, V.I. [ITEP, B. Cheremushkinskaya 25, Moscow, 117218 (Russian Federation); Max-Planck-Institut fuer Physik, Foehringer Ring 6, 80805 Munich (Germany)

    2010-10-15

    We discuss the role of the magnetic degrees of freedom of the gluon plasma in its viscosity. The main assumption is that motions of the magnetic component and of the rest of the plasma can be considered as independent. The magnetic component in the deconfined phase is described by a three-dimensional (Euclidean) field theory. The parameters of the theory can be estimated phenomenologically. It is not ruled out that the magnetic component is superfluid.

  13. Global scaling symmetry, Noether charge, and universality of shear viscosity

    Science.gov (United States)

    Liu, Hai-Shan

    2016-05-01

    Recently, it was established in Einstein-Maxwell-Dilaton gravity that the Kovtun-Son-Starinets viscosity/entropy ratio associated with anti-de Sitter planar black holes can be viewed as the boundary dual to the generalized Smarr relation of the black holes in the bulk. In this paper, we establish this relation in Einstein gravity with general minimally coupled matter and also in theories with an additional nonminimally coupled scalar field. We consider two examples for explicit demonstrations.

  14. Dynamic viscosity mapping of the oxidation of squalene aerosol particles.

    OpenAIRE

    Athanasiadis, Athanasios; Fitzgerald, Clare; Davidson, Nicholas M; Giorio, Chiara; Botchway, Stanley W; Ward, Andrew D.; Kalberer, Markus; Pope, Francis D.; Kuimova, Marina K.

    2016-01-01

    Organic aerosols (OAs) play important roles in multiple atmospheric processes, including climate change, and can impact human health. The physico-chemical properties of OAs are important for all these processes and can evolve through reactions with various atmospheric components, including oxidants. The dynamic nature of these reactions makes it challenging to obtain a true representation of their composition and surface chemistry. Here we investigate the microscopic viscosity of the model OA...

  15. Ward identities and relations between conductivities and viscosities in holography

    CERN Document Server

    Hoyos, Carlos

    2015-01-01

    We derive relations between viscosities and momentum conductivity in $2+1$ dimensions by finding a generalization of holographic Ward identities for the energy-momentum tensor. The generalization is novel in the sense that it goes beyond the usual identities obtained from holographic renormalization. Our results are consistent with previous field theory analysis. The main tools we use are a constant `probability current' in the gravity dual, that we are able to define for any system of linear ODEs, and parity symmetry.

  16. Accelerating cosmological expansion from shear and bulk viscosity

    CERN Document Server

    Floerchinger, Stefan; Wiedemann, Urs Achim

    2015-01-01

    The dissipation of energy from local velocity perturbations in the cosmological fluid affects the time evolution of spatially averaged fluid dynamic fields and the cosmological solution of Einstein's field equations. We show how this backreaction effect depends on shear and bulk viscosity and other material properties of the dark sector, as well as the spectrum of perturbations. If sufficiently large, this effect could account for the acceleration of the cosmological expansion.

  17. Accelerating Cosmological Expansion from Shear and Bulk Viscosity

    Science.gov (United States)

    Floerchinger, Stefan; Tetradis, Nikolaos; Wiedemann, Urs Achim

    2015-03-01

    The dissipation of energy from local velocity perturbations in the cosmological fluid affects the time evolution of spatially averaged fluid dynamic fields and the cosmological solution of Einstein's field equations. We show how this backreaction effect depends on shear and bulk viscosity and other material properties of the dark sector, as well as the spectrum of perturbations. If sufficiently large, this effect could account for the acceleration of the cosmological expansion.

  18. Viscosity and Softening Behavior of Alkali Zinc Sulfophosphate Glasses

    DEFF Research Database (Denmark)

    Da, Ning; Krolikowski, Sebastian; Nielsen, Karsten Hansgaard;

    2010-01-01

    We report on the softening properties and viscosity of glasses from the system ZnO-Na2O-SO3-P2O5 for low-temperature sealing applications. Up to a ratio of network-forming ions PO(4)3-:SO(4)2- of about 2:1, a gradual substitution of P2O5 by SO3 results in decreasing glass transition and softening...

  19. Observational constraints on viscosity in AGN accretion discs

    Energy Technology Data Exchange (ETDEWEB)

    Siemiginowska, A.; Czerny, B. (N. Copernicus Astronomical Centre, Warsaw (Poland))

    1989-07-15

    The optical/UV/soft X-ray big bump can be modelled as thermal emission from an accretion disc. The observed UV variability in AGN spectra may be caused by accretion-disc instabilities, and can be used to constrain the viscosity. The comparison of thermal time-scales with the observed time-scales of variability in 10 Seyfert galaxies and 16 QSOs indicates values for the parameter {alpha} of the order of 0.01 for most cases. (author).

  20. Moving forward to constrain the shear viscosity of QCD matter

    OpenAIRE

    Denicol, Gabriel; Monnai, Akihiko; Schenke, Bjoern

    2015-01-01

    We demonstrate that measurements of rapidity differential anisotropic flow in heavy ion collisions can constrain the temperature dependence of the shear viscosity to entropy density ratio {\\eta}/s of QCD matter. Comparing results from hydrodynamic calculations with experimental data from RHIC, we find evidence for a small {\\eta}/s $\\approx$ 0.04 in the QCD cross-over region and a strong temperature dependence in the hadronic phase. A temperature independent {\\eta}/s is disfavored by the data....

  1. Global Scaling Symmetry, Noether Charge and Universality of Shear Viscosity

    CERN Document Server

    Liu, Hai-Shan

    2016-01-01

    Recently it was established in Einstein-Maxwell-Dilaton gravity that the KSS viscosity/entropy ratio associated with AdS planar black holes can be viewed as the boundary dual to the generalized Smarr relation of the black holes in the bulk. In this paper we establish this relation in Einstein gravity with general minimally-coupled matter, and also in theories with an additional non-minimally coupled scalar field. We consider two examples for explicit demonstrations.

  2. Synthetic Organic Electrochemistry in Ionic Liquids: The Viscosity Question

    OpenAIRE

    Handy, Scott T.; Steven Bornemann

    2011-01-01

    Ionic liquids are obvious candidates for use in electrochemical applications due to their ionic character. Nevertheless, relatively little has been done to explore their application in electrosynthesis. We have studied the Shono oxidation of arylamines and carbamates using ionic liquids as recyclable solvents and have noted that the viscosity of the medium is a major problem, although with the addition of sufficient co-solvent, good results and excellent recovery and recycling of the ionic li...

  3. A unified equation for the viscosity of pure liquid metals

    Energy Technology Data Exchange (ETDEWEB)

    Kaptay, G. [Dept. of Chemistry, Univ. of Miskolc, Miskolc-Egyetemvaros (Hungary)

    2005-01-01

    The following unified equation has been elaborated in the present paper, to describe the viscosity of all liquid metals as a function of temperature: {eta}{sub i} = A . M{sub i}{sup 1/2} / V{sub i}{sup 2/3} . T{sup 1/2} . exp (B . T{sub m,i} / T) with {eta}{sub i}, M{sub i}, V{sub i}, T{sub m,i} being the dynamic viscosity, atomic mass, molar volume and melting point of the given metal i, and T is temperature. The above equation was tested on 101 measured points of 15 selected liquid metals, and the average values of the generally valid parameters were found as: A = (1.80 {+-} 0.39) . 10{sup -8} (J/Kmol{sup 1/3}){sup 1/2}, B = 2.34 {+-} 0.20. Based on these parameters, the temperature dependence of viscosity was estimated for 32 liquid metals. The above equation was derived by (i) combining Andrade's equation with the activation energy concept, and (ii) by combining Andrade's equation with the free volume concept. It is shown, that the activation energy and the free volume concepts have identical roots and lead to identical results. The above equation is shown to be valid for liquid semi-metals (Si,Ge,Sb,Bi), if their actual melting points are replaced by their corrected melting points, corresponding to (unstable) metallic solid crystals. The ratio of viscosity to surface tension of pure liquid metals is discussed, as well. (orig.)

  4. The impact of viscosity on the morphology of gaseous flows in semidetached binary systems

    CERN Document Server

    Bisikalo, D V; Kuznetsov, O A; Chechetkin, V M

    2000-01-01

    Results of 3D gas dynamical simulation of mass transfer in binaries are presented for systems with various values of viscosity. Analysis of obtained solutions shows that in the systems with low value of viscosity the flow structure is qualitatively similar to one for systems with high viscosity. Presented calculations confirm that there is no shock interaction between the stream from L1 and the forming accretion disk (`hot spot') at any value of viscosity.

  5. Estimate of the Bulk Viscosity in the Cosmic Fluid

    CERN Document Server

    Normann, Ben David

    2016-01-01

    We first give a review of recent works on bulk viscous cosmology. Then, we derive general solutions of the Friedmann equations when bulk viscosity is included in the energy-momentum tensor, both for a single-component and a multicomponent fluid, showing that these general solutions reduce to those found in the literature in special cases. We solve the energy conservation equation for the three cases $\\zeta$=const., $\\zeta\\propto \\sqrt{\\rho}$, and $\\zeta\\propto \\rho$, often studied in previous investigations, and find the best-fit values for the present day viscosity $\\zeta_0$ in each of the three cases. Taking into account constraints from thermodynamics we find, in agreement with previous works, that the present day viscosity is less than about $ 10^7~$Pa s. In fact the best fit values suggest $\\zeta_0\\sim 10^6$Pa s. We point out that this magnitude is acceptable from a hydrodynamic point of view. Altogether, we give preference to the model $\\zeta\\propto \\sqrt{\\rho}$, which by now seems to be widely accepted...

  6. Low viscosity hydrogel of guar gum: preparation and physicochemical characterization.

    Science.gov (United States)

    Cunha, Pablyana L R; Castro, Rondinelle R; Rocha, Francisco A C; de Paula, Regina C M; Feitosa, Judith P A

    2005-10-30

    Guar gum was cross-linked with glutaraldehyde and characterized by GPC, rheology, WADX, SEM and TGA. This guar gum is a galactomannan polysaccharide, that contains small amount of arabinose, glucose and uronic acid, besides galactose and mannose. The polymer has high molar mass, with Mw, Mn and Mv values of 2.0x10(6), 1.2x10(6) and 1.9x10(6)g/mol, respectively. The reticulation follows a slow process and lead to a viscosity increase of 40 times compared with the original gum solution. The final viscosity was similar to that of Hylan G-F 20, a hyaluronate derivative, commercially used in viscosupplementation treatment. The gel contains 95.6% of water and the amount of residual glutaraldehyde is much lower than the LD-50. Porous structure was detected by SEM and thermal stability was improved by the cross-linking. The low viscosity, the small amount of remained glutaraldehyde, and the thermal stability indicates that the guar hydrogel has potential to be applied as biomaterial with specific rheological requirements.

  7. Temperature-Dependent Conformations of Model Viscosity Index Improvers

    Energy Technology Data Exchange (ETDEWEB)

    Ramasamy, Uma Shantini; Cosimbescu, Lelia; Martini, Ashlie

    2015-05-01

    Lubricants are comprised of base oils and additives where additives are chemicals that are deliberately added to the oil to enhance properties and inhibit degradation of the base oils. Viscosity index (VI) improvers are an important class of additives that reduce the decline of fluid viscosity with temperature [1], enabling optimum lubricant performance over a wider range of operating temperatures. These additives are typically high molecular weight polymers, such as, but not limited to, polyisobutylenes, olefin copolymer, and polyalkylmethacrylates, that are added in concentrations of 2-5% (w/w). Appropriate polymers, when dissolved in base oil, expand from a coiled to an uncoiled state with increasing temperature [2]. The ability of VI additives to increase their molar volume and improve the temperature-viscosity dependence of lubricants suggests there is a strong relationship between molecular structure and additive functionality [3]. In this work, we aim to quantify the changes in polymer size with temperature for four polyisobutylene (PIB) based molecular structures at the nano-scale using molecular simulation tools. As expected, the results show that the polymers adopt more conformations at higher temperatures, and there is a clear indication that the expandability of a polymer is strongly influenced by molecular structure.

  8. Modeling of the eddy viscosity by breaking waves

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Breaking wave induced nearsurface turbulence has important consequences for many physical and biochemical processes including water column and nutrients mixing, heat and gases exchange across air-sea interface. The energy loss from wave breaking and the bubble plume penetration depth are estimated. As a consequence, the vertical distribution of the turbulent kinetic energy (TKE), the TKE dissipation rate and the eddy viscosity induced by wave breaking are also provided. It is indicated that model results are found to be consistent with the observational evidence that most TKE generated by wave breaking is lost within a depth of a few meters near the sea surface. High turbulence level with intensities of eddy viscosity induced by breaking is nearly four orders larger than υwl(=κu *wz), the value predicted for the wall layer scaling close to the surface, where u *w is the friction velocity in water, κ with 0.4 is the von Kármán constant, and z is the water depth, and the strength of the eddy viscosity depends both on wind speed and sea state, and decays rapidly through the depth. This leads to the conclusion that the breaking wave induced vertical mixing is mainly limited to the near surface layer, well above the classical values expected from the similarity theory. Deeper down, however, the effects of wave breaking on the vertical mixing become less important.

  9. Molecular mechanism of the viscosity of aqueous glucose solutions

    Science.gov (United States)

    Bulavin, L. A.; Zabashta, Yu. F.; Khlopov, A. M.; Khorol'skii, A. V.

    2017-01-01

    Experimental relations are obtained for the viscosity of aqueous glucose solutions in the temperature range of 10-80°C and concentration range 0.01-2.5%. It is found that the concentration dependence of fluidity is linear when the concentration is higher than a certain value and varies at different temperatures. The existence of such a dependence indicates that the mobilities of solvent and solute molecules are independent of the concentration of solutions. This assumption is used to construct a theoretical model, in which the structure of an aqueous glucose solution is presented as a combination of two weakly interacting networks formed by hydrogen bonds between water molecules and between glucose molecules. Theoretical relations are obtained using this model of network solution structure for the concentration and temperature dependence of solution viscosity. Experimental data are used to calculate the activation energies for water ( U w = 3.0 × 10-20 J) and glucose molecules ( U g = 2.8 × 10-20 J). It is shown that the viscosity of a solution in such a network structure is governed by the Brownian motion of solitons along the chains of hydrogen bonds. The weak interaction between networks results in the contributions to solution fluidity made by the motion of solitons in both of them being almost independent.

  10. A Study of Eddy Viscosity Coefficient in Numerical Tidal Simulation

    Institute of Scientific and Technical Information of China (English)

    陈永平; 雷智益

    2001-01-01

    Based on the fluid motion equations, the physical meaning of eddy viscosity coefficient and the rationality of theBoussinesq hypothesis are discussed in this paper. The effect of the coefficient on numerical stability is analyzed briefly.A semi-enclosed rectangular sea area, with an orthogonal spur dike, is applied in a 2-D numerical model to study the effect of horizontal eddy viscosity coefficient (AH). The computed result shows that AH has little influence on the tidal level and averaged flow velocity, but has obvious influence on the intensity and the range of return flow around near thespur dike. Correspondingly, a wind-driven current pool and an annular current are applied in a 3-D numerical modelrespectively to study the effect of vertical eddy viscosity coefficient (AV). The computed result shows that the absolute value of AV is inversely proportional to that of horizontal velocity, and the vertical gradient value of AV determines the ver-tical distribution of horizontal velocity. The distribution form of AV is theoretically recommended as a parabolic type, ofwhich the maximum value appears at 0.5 H.

  11. Changes in erythrocytic deformability and plasma viscosity in neonatal ictericia.

    Science.gov (United States)

    Bonillo-Perales, A; Muñoz-Hoyos, A; Martínez-Morales, A; Molina-Carballo, A; Uberos-Fernández, J; Puertas-Prieto, A

    1999-01-01

    We studied 45 full-term newborns divided into 3 groups. Group 1: 17 newborns with bilirubin ictericia (bilirubin 11-20 mg/dL) and Group 3: 10 newborns with moderate hemolytic ictericia needing exchange transfusion. The following were studied: erythrocytic deformability, plasma viscosity, plasmatic osmolarity, seric bilirubin, bilirubin/albumin ratio, free fatty acids and corpuscular volume of the erythrocytes. In full-term newborns, the following are risk factors for increased erythrocytic rigidity: neonatal hemolytic illness (p = 0.004, odds ratio: 7.02), increases in total bilirubin (p = 0.02, odds ratio: 4.3) and increases in the bilirubin/albumin ratio (p = 0.025, odds ratio: 4.25). Furthermore, the most important risk factor for high plasma viscosity is also neonatal hemolytic illness (p = 0.01, odds ratio: 2.30). The role of total bilirubin is also important (p = 0.09, odds ratio: 2.10), while that of the bilirubin/albumin ratio (p = 0.012, NS) is less so. The greater the hemolysis, the greater the erythrocytic rigidity and plasma viscosity (p ictericia, hemolytic illness and increases in the bilirubin/albumin ratio are accompanied by rheological alterations that could affect cerebral microcirculation and cause a neurological deficit not exclusively related to the levels of bilirubin in plasma.

  12. Shear viscosity and chemical equilibration of the QGP

    CERN Document Server

    Plumari, Salvatore; Colonna, Maria; Scardina, Francesco; Greco, Vincenzo

    2012-01-01

    We have investigated, in the frame work of the transport approach, different aspects of the QGP created in Heavy Ion Collisions at RHIC and LHC energies. The shear viscosity $\\eta$ has been calculated by using the Green-Kubo relation at the cascade level. We have compared the numerical results for $\\eta$ obtained from the Green-Kubo correlator with the analytical formula in both the Relaxation Time Approximation (RTA) and the Chapman-Enskog approximation (CE). From this comparison we show that in the range of temperature explored in a Heavy Ion collision the RTA underestimates the viscosity by about a factor of 2, while a good agreement is found between the CE approximation and Gree-Kubo relation already at first order of approximation. The agreement with the CE approximation supplies an analytical formula that allows to develop kinetic transport theory at fixed shear viscosity to entropy density ratio, $\\eta/s$. We show some results for the build up of anisotropic flows $v_{2}$ in a transport approach at fix...

  13. HIGHER VISCOSITY OF LOGWAY FRACTURE FOR WIRE DRAWING

    Directory of Open Access Journals (Sweden)

    V. N. Kovalevsky

    2009-01-01

    Full Text Available The paper presents results of the investigations on evaluation of logway resistance which are used for drawing cord wire made of tungsten-containing hard alloy. It has been shown that complicated loading conditions lead to fracture of a tool surface and these conditions are attributed to the action of various mechanisms: wearing due to high local stresses and deformations, fracture due to stretching stresses at logway expansion, small-cycle fatigue, heat shock etc. It is proposed to evaluate logway serviceability by such indices as hardness, strength and fracture viscosity and an amount of bundle and size of tungsten carbide grain influence on these indices.  As an alternative material to a hard alloy it is advanced to use a diamond-silicon carbide composite. It is shown that a preliminary protection of diamond crystals with the help of a-SiC nano-coating makes it possible to obtain super-hard material. Its fracture viscosity can be compared with the fracture viscosity of a hard alloy and the composite out-performs a hard alloy in respect of wear characteristics that ensures rather good prospects for its application for manufacturing logways

  14. Energy Loss in Pulse Detonation Engine due to Fuel Viscosity

    Directory of Open Access Journals (Sweden)

    Weipeng Hu

    2014-01-01

    Full Text Available Fluid viscosity is a significant factor resulting in the energy loss in most fluid dynamical systems. To analyze the energy loss in the pulse detonation engine (PDE due to the viscosity of the fuel, the energy loss in the Burgers model excited by periodic impulses is investigated based on the generalized multisymplectic method in this paper. Firstly, the single detonation energy is simplified as an impulse; thus the complex detonation process is simplified. And then, the symmetry of the Burgers model excited by periodic impulses is studied in the generalized multisymplectic framework and the energy loss expression is obtained. Finally, the energy loss in the Burgers model is investigated numerically. The results in this paper can be used to explain the difference between the theoretical performance and the experimental performance of the PDE partly. In addition, the analytical approach of this paper can be extended to the analysis of the energy loss in other fluid dynamic systems due to the fluid viscosity.

  15. Shear viscosity of nanofluids mixture%纳米流体黏度特性

    Institute of Scientific and Technical Information of China (English)

    凌智勇; 邹涛; 丁建宁; 程广贵; 张忠强; 孙东建; 钱龙

    2012-01-01

    The influences of temperature, chemical dispersant, and volume fraction of nanoparticles on the shear viscosity of the nanoparticle-fluid mixture were experimentally investigated. The nanofluids including different types of nanoparticles were prepared by a two-steps method. The results showed that the shear viscosity of the mixture decreased with increasing temperature below a threshold of 60℃ . Interestingly, the viscosity of Cu-water and Al2O3-water nanofluids increased with increasing temperature above 60℃ . The Brownian motion was enhanced as temperature increased, and the moving of the nanoparticles covering surfactants would increase the viscosity. The viscosity hysteresis between the heating and cooling processes could be observed obviously. The shear viscosity of CuO-water nanofluid in this experiment was in good agreement with fluid dynamics continuum theory for the fluids without dispersant. After the dispersant was added in CuO-water nanofluid, the experimental value of shear viscosity was larger than the theoretical data. And the varying trend of viscosity was consistent with that of the dispersant. The use of surfactant had an important role in the calculation of viscosity. The viscosity of nanofluids increased with increasing particle volume fraction, but the viscosity increments for the nanofluids with the same particle volume fraction were not the same. So density, surface electrical and diameter of the nanoparticles should be considered when calculating the viscosity of nanofluids.

  16. Universality of the high-temperature viscosity limit of silicate liquids

    DEFF Research Database (Denmark)

    Zheng, Qiuju; Mauro, John C.; Ellison, Adam J.;

    2011-01-01

    We investigate the high-temperature limit of liquid viscosity by analyzing measured viscosity curves for 946 silicate liquids and 31 other liquids including metallic, molecular, and ionic systems. Our results show no systematic dependence of the high-temperature viscosity limit on chemical compos...

  17. Process for stabilizing the viscosity characteristics of coal derived materials and the stabilized materials obtained thereby

    Energy Technology Data Exchange (ETDEWEB)

    Bronfenbrenner, James C. (Allentown, PA); Foster, Edward P. (Allentown, PA); Tewari, Krishna (Allentown, PA)

    1985-01-01

    A process is disclosed for stabilizing the viscosity of coal derived materials such as an SRC product by adding up to 5.0% by weight of a light volatile phenolic viscosity repressor. The viscosity will remain stabilized for a period of time of up to 4 months.

  18. Process for stabilizing the viscosity characteristics of coal derived materials and the stabilized materials obtained thereby

    Energy Technology Data Exchange (ETDEWEB)

    Bronfenbrenner, J.C.; Foster, E.P.

    1985-11-26

    A process is disclosed for stabilizing the viscosity of coal derived materials such as an SRC product by adding up to 5.0% by weight of a light volatile phenolic viscosity repressor. The viscosity will remain stabilized for a period of time of up to 4 months.

  19. Interpretation of the complex viscosity of dense hard-sphere dispersions

    NARCIS (Netherlands)

    Mellema, J.; Werff, van der J.C.; Blom, C.; Kruif, de C.G.

    1989-01-01

    The complex viscosity of dense hard-sphere dispersions has been determined recently over a large frequency range. If conceived as a homogeneous system with continuously distributed elasticity and viscosity, the complex viscosity can be described theoretically with a constant relaxation strength and

  20. Immunoelectrophoresis - blood

    Science.gov (United States)

    IEP - serum; Immunoglobulin electrophoresis - blood; Gamma globulin electrophoresis; Serum immunoglobulin electrophoresis; Amyloidosis - electrophoresis serum; Multiple myeloma - serum electrophoresis; Waldenström - serum electrophoresis

  1. A new look at blood shear-thinning

    CERN Document Server

    Lanotte, Luca; Mendez, Simon; Fedosov, Dmitry A; Fromental, Jean-Marc; Clavería, Viviana; Nicoud, Franck; Gompper, Gerhard; Abkarian, Manouk

    2016-01-01

    Blood viscosity decreases with shear stress, a property essential for an efficient perfusion of the vascular tree. Shear-thinning is intimately related to the dynamics and mutual interactions of red blood cells (RBCs), the major constituents of blood. Our work explores RBCs dynamics under physiologically relevant conditions of flow strength, outer fluid viscosity and volume fraction. Our results contradict the current paradigm stating that RBCs should align and elongate in the flow direction thanks to their membrane circulation around their center of mass, reducing flow-lines disturbances. On the contrary, we observe both experimentally and with simulations, rich morphological transitions that relate to global blood rheology. For increasing shear stresses, RBCs successively tumble, roll, deform into rolling stomatocytes and finally adopt highly deformed and polylobed shapes even for semi-dilute volume fractions analogous to microcirculatory values. Our study suggests that any pathological change in plasma com...

  2. Mathematical analysis of non-Newtonian blood flow in stenosis narrow arteries.

    Science.gov (United States)

    Sriyab, Somchai

    2014-01-01

    The flow of blood in narrow arteries with bell-shaped mild stenosis is investigated that treats blood as non-Newtonian fluid by using the K-L model. When skin friction and resistance of blood flow are normalized with respect to non-Newtonian blood in normal artery, the results present the effect of stenosis length. When skin friction and resistance of blood flow are normalized with respect to Newtonian blood in stenosis artery, the results present the effect of non-Newtonian blood. The effect of stenosis length and effect of non-Newtonian fluid on skin friction are consistent with the Casson model in which the skin friction increases with the increase of either stenosis length or the yield stress but the skin friction decreases with the increase of plasma viscosity coefficient. The effect of stenosis length and effect of non-Newtonian fluid on resistance of blood flow are contradictory. The resistance of blood flow (when normalized by non-Newtonian blood in normal artery) increases when either the plasma viscosity coefficient or the yield stress increases, but it decreases with the increase of stenosis length. The resistance of blood flow (when normalized by Newtonian blood in stenosis artery) decreases when either the plasma viscosity coefficient or the yield stress increases, but it decreases with the increase of stenosis length.

  3. Understanding Blood Counts

    Science.gov (United States)

    ... Lab and Imaging Tests Understanding Blood Counts Understanding Blood Counts Understanding Blood Counts SHARE: Print Glossary Blood cell counts give ... your blood that's occupied by red cells. Normal Blood Counts Normal blood counts fall within a range ...

  4. Experimental and Predicted Viscosities of Binary Mixtures Containing Chlorinated and Oxygenated Compounds

    Science.gov (United States)

    Montaño, D.; Artigas, H.; Royo, F. M.; Lafuente, Carlos

    2013-01-01

    This study presents the viscosities, both kinematic and dynamic, of binary mixtures of 1-chlorobutane, 2-chlorobutane, or 1-chloro-2-methylpropane with butyl ethyl ether or methyl tert-butyl ether from T = 283.15 K to T = 313.15 K at atmospheric pressure as a function of composition. Kinematics viscosities were measured using an Ubbelohde viscometer. The dynamic viscosities were obtained from experimental kinematic viscosities and previously reported density data. The viscosity results have been employed to check the reliability of the Wu-UNIFAC method.

  5. BLOOD DONATION

    CERN Multimedia

    SC Unit

    2008-01-01

    A blood donation, organized by EFS (Etablissement Français du Sang) of Annemasse will take place On Wednesday 12 November 2008, from 8:30 to 16:00, at CERN Restaurant 2 If possible, please, bring your blood group Card.

  6. Blood donation

    CERN Multimedia

    GS Department

    2009-01-01

    A blood donation is organised by the Cantonal Hospital of Geneva On Thursday 19 March 2009 from 9 a.m. to 5 p.m. CERN RESTAURANT 2 Number of donations during the last blood donations :135 donors in July 2008 122 donors in November 2008 Let’s do better in 2009 !!! Give 30 minutes of your time to save lives...

  7. Effect of safflower yellow pigment sodium chloride injection on hemorheology and blood coagulation function in patients with hip replacement surgery

    Institute of Scientific and Technical Information of China (English)

    Zhi Wang; Wei-Xin Yang; Xiu-Hua Zhang; Xian Jiang

    2016-01-01

    Objective:To investigate the effect of safflower yellow pigment sodium chloride injection on hemorheology and coagulation function in patients with hip replacement surgery.Methods:A total of 80 cases of hip joint replacement were divided into two groups according to the random number table method, 40 cases in each group. Patients in two groups were conducted with regular hip replacement, postoperative conventional symptomatic treatment. Based on it, patients of the observation group started to get the safflower yellow pigment and sodium chloride injection in the first week after operation, intravenous injection. A total of 3 weeks of treatment. blood rheological index were compared including plasma viscosity, whole blood viscosity at high shear, low shear whole blood viscosity, red blood cell hematocrit and blood coagulation indexes: prothrombin time (PT), activation activated partial thromboplastin time (APTT), thrombin time (TT), D-Dimer (D-D), fibrinogen (FIB) between the two groups postoperative 1 week, postoperative 2 weeks and postoperative 4 weeks.Results:The plasma viscosity, high shear viscosity of whole blood, low shear viscosity of whole blood, D-D in control group postoperative 2 week and 4 week were significantly higher than that of preoperative 1 week; while red blood cell volume, PT, APTT, TT, Fib were significantly lower than preoperative 1 week (P0.05). The PT, APTT in observation group postoperative 2 week and 4 week were significantly increased compared with preoperative 1 week, and the TT in observation group postoperative 4 week was significantly increased compared with preoperative 1 week (P<0.05); The plasma viscosity, high shear viscosity of whole blood, low shear viscosity of whole blood, D-D in observation group were significantly lower, while the PT, APTT, TT, Fib in observation group were significantly higher than that in control group in the same time point (P<0.05).Conclusions:Hip replacement will cause the change of blood rheology in

  8. Tainted blood

    DEFF Research Database (Denmark)

    Deleuran, Ida; Sheikh, Zainab Afshan; Hoeyer, Klaus

    2015-01-01

    study of the historical rise and current workings of safety practices in the Danish blood system. Here, we identify a strong focus on contamination in order to avoid 'tainted blood', at the expense of working with risks that could be avoided through enhanced blood monitoring practices. Of further...... significance to this focus are the social dynamics found at the heart of safety practices aimed at avoiding contamination. We argue that such dynamics need more attention, in order to achieve good health outcomes in transfusion medicine. Thus, we conclude that, to ensure continuously safe blood systems, we...... need to move beyond the bifurcation of the social and medical aspects of blood supply as two separate issues and approach social dynamics as key medical safety questions....

  9. Dependence of viscosity of Cu9In4 intermetallics melt on thermal history

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The temperature dependence of the dynamic viscosity of Cu9In4 intermetallics melt has been investigated in five kinds of different heating and cooling processes with a torsional oscillation viscometer. It has been found that the viscosity of all Cu9In4 intermetallics decreases with increasing temperature in five kinds of different thermal processes. Thermal history has considerable effect on the viscosity. The viscosity in the cooling process with high superheating is greater than that in the cooling process with low superheating. The viscosity in the heating process is greater than that in the cooling process.No anomalous change in viscosity is measured in three kinds of cooling processes with low superheating. The anomalous change occurs at about 1050℃ in cooling with high superheating and at 800℃ in heating. Furthermore, the structural variation in different thermal processes has also been discussed on the basis of the change in viscosity and DSC analysis.

  10. Experimental determination of viscosity of water based magnetite nanofluid for application in heating and cooling systems

    Science.gov (United States)

    Toghraie, Davood; Alempour, Seyed Mohammadbagher; Afrand, Masoud

    2016-11-01

    In this paper, experimental determination of dynamic viscosity of water based magnetite nanofluid (Fe3O4/water) was performed. The viscosity was measured in the temperature range of 20-55 °C for various samples with solid volume fractions of 0.1%, 0.2%, 0.4%, 1%, 2% and 3%. The results showed that the viscosity considerably decreases with increasing temperature. Moreover, the viscosity enhances with an increase in the solid volume fraction, remarkably. The calculated viscosity ratios showed that the maximum viscosity enhancement was 129.7%. Using experimental data, a new correlation has been proposed to predict the viscosity of magnetite nanofluid (Fe3O4/water). A comparison between the experimental results and the correlation outputs showed that the proposed model has a suitable accuracy.

  11. Employing Taylor and Heisenberg subfilter viscosities to simulate turbulent statistics in LES models

    Science.gov (United States)

    Degrazia, G. A.; Rizza, U.; Puhales, F. S.; Welter, G. S.; Acevedo, O. C.; Maldaner, S.

    2012-02-01

    A turbulent subfilter viscosity for Large Eddy Simulation (LES) based on the Taylor statistical diffusion theory is proposed. This viscosity is described in terms of a velocity variance and a time scale, both associated to the inertial subrange. This new subfilter viscosity contains a cutoff wavenumber kc, presenting an identical form (differing by a constant) to the Heisenberg subfilter viscosity. Therefore, both subfilter viscosities are described in terms of a sharp division between large and small wavenumbers of a turbulent flow and, henceforth, Taylor and Heisenberg subfilter viscosities are in agreement with the sharp Fourier filtering operation, frequently employed in LES models. Turbulent statistics of different orders, generated from atmospheric boundary layer simulations employing both Taylor and Heisenberg subfilter viscosities have been compared with observations and results provided by other simulations. The comparison shows that the LES model utilizing the approaches of Taylor and Heisenberg reproduces these turbulent statistics correctly in different vertical regions of a planetary convective boundary layer (CBL).

  12. What Happens to Donated Blood?

    Science.gov (United States)

    ... week. Learn About Blood Blood Facts and Statistics Blood Components Whole Blood and Red Blood Cells Platelets Plasma ... About Blood Blood Facts and Statistics Blood Types Blood Components What Happens to Donated Blood Blood and Diversity ...

  13. Separation of blood cells using hydrodynamic lift

    Science.gov (United States)

    Geislinger, T. M.; Eggart, B.; Braunmüller, S.; Schmid, L.; Franke, T.

    2012-04-01

    Using size and deformability as intrinsic biomarkers, we separate red blood cells (RBCs) from other blood components based on a repulsive hydrodynamic cell-wall-interaction. We exploit this purely viscous lift effect at low Reynolds numbers to induce a lateral migration of soft objects perpendicular to the streamlines of the fluid, which closely follows theoretical prediction by Olla [J. Phys. II 7, 1533, (1997)]. We study the effects of flow rate and fluid viscosity on the separation efficiency and demonstrate the separation of RBCs, blood platelets, and solid microspheres from each other. The method can be used for continuous and label-free cell classification and sorting in on-chip blood analysis.

  14. The influence of investigated factors on viscosity of stirred yogurt

    Directory of Open Access Journals (Sweden)

    Denin-Đurđević Jelena D.

    2002-01-01

    Full Text Available Skim milk was reconstituted to obtain milk with 8.44% DM, which was standardized with demineralized whey powder (DWP to obtain milk sample A (9.71% DM and milk sample B (10.75% DM. Milk samples were heat treated at 85ºC/20 min and 90ºC/10 min, respectively. Untreated milk was used as control. Milk samples were inoculated with 2.5% of commercial yogurt culture (containing Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus in the ratio 1:1 at 43ºC. Samples were incubated until pH 4.6 was reached. Samples were immediately cooled to 4ºC and held at that temperature until analyses. Samples of acid casein gels were stirred after 1, 7 and 14 days of storage. Measurements of viscosity were done with Brookfield DV-E Viscometer. Spindle No 3 at 30 rpm was used for all samples. Duration of fermentation decreased when DWP was used for standardization of milk dry matter content. Yogurt samples produced from milk heat treated at 85ºC/20 min, obtained by stirring of gel 1 day after production had a higher viscosity than sample produced from milk heat treated at 90ºC/10 min. On the other hand, samples produced from milk heat treated at 90ºC/10 min had a greater viscosity after 7 and 14 days of storage, which indicates a greater hydrophilic properties and a more pronounced swelling of casein micelles.

  15. A first approaching to work with viscosity in college level

    Science.gov (United States)

    Carmona, Karla; Flores, Sergio; Alfaro, Luis L.; Gonzalez, Maria D.

    2008-10-01

    Working with the concepts of flow, velocity and emptying time, in containers with different area, the research group named Physics and Mathematics in Context from the University of Juarez in Mexico is attempting to experiment with the relationship between the geometry of the containers and their discharge time with different kind of liquids. Thus, we have built two different sets of containers, and use kitchen oil, maple syrup, and car oil. Where the cross area is constant: prisms with bases of different geometries. Thus, in order to achieve a better understanding related to differential equations situations and introduce viscosity.

  16. Synthesis of biolubricants with high viscosity and high oxidation stability

    Directory of Open Access Journals (Sweden)

    Bondioli Paolo

    2003-03-01

    Full Text Available The synthetic procedure as well as the main properties of obtained products of a group of complex esters are reported here. Complex esters were prepared using low molecular weight saturated fatty acids, trimethylolpropane and a dicarboxylic acid as a feedstock. By means of this procedure it is possible to obtain products having high viscosity and very good lubricating, thermal and cold properties. Thanks to the absence of unsaturations into the ester also the oxidation property is good, opening several application perspective for these products which are partly prepared from renewable source.

  17. The role of extensional viscosity in frog tongue projection

    Science.gov (United States)

    Noel, Alexis; Wagner, Caroline; McKinley, Gareth; Mendelson, Joe; Hu, David

    2014-11-01

    Frogs and other amphibians capture insects through high-speed tongue projection, some achieving tongue accelerations of over fifty times gravity. In this experimental study, we investigate how a frog's sticky saliva enables high-speed prey capture. At the Atlanta zoo, we used high-speed video to film the trajectory of frog tongues during prey capture. We have also designed and built a portable extensional rheometer; by following the capillary-driven thinning in the diameter of a thread of saliva we characterize the relaxation time and extensional viscosity and so infer the adhesive force between the frog tongue and prey.

  18. Fluid Dynamics and Viscosity in Strongly Correlated Fluids

    CERN Document Server

    Schaefer, Thomas

    2014-01-01

    We review the modern view of fluid dynamics as an effective low energy, long wavelength theory of many body systems at finite temperature. We introduce the notion of a nearly perfect fluid, defined by a ratio $\\eta/s$ of shear viscosity to entropy density of order $\\hbar/k_B$ or less. Nearly perfect fluids exhibit hydrodynamic behavior at all distances down to the microscopic length scale of the fluid. We summarize arguments that suggest that there is fundamental limit to fluidity, and review the current experimental situation with regard to measurements of $\\eta/s$ in strongly coupled quantum fluids.

  19. Variations for Pure Cu Melt Viscosity with Different Atmospheres

    Institute of Scientific and Technical Information of China (English)

    耿红霞; 耿浩然; 薛宪营; 郁可; 刘建同

    2003-01-01

    The viscosity of Cu melt is obtained to be in the ranges from 2.418 to 3.039mPa.s under vacuum atmosphere (2Pa), from 2.907 to 3.425mPa.s under nitrogen gas atmosphere and from 3.352 to 4.015mPa.s under argon gas atmosphere. The activation energy is estimated to be 0.224, 0.162 and 0.150eV for the vacuum atmosphere (2 Pa), nitrogen gas atmosphere and argon gas atmosphere, respectively. The results reflect the essential structural change in the Cu melt by using different atmospheres.

  20. Measurement of Liquid Viscosities in Tapered or Parabolic Capillaries.

    Science.gov (United States)

    Ershov; Zorin; Starov

    1999-08-01

    The possibility of using tapered or parabolic capillaries for measurement of liquid viscosities is investigated both experimentally and theoretically. It is demonstrated that even small deviations in capillary radius from a constant value may substantially affect measurement results. Equations are derived which allow correct analysis of the measurement results in tapered or parabolic capillaries. The following cases are analyzed: a water imbibition into a tapered or parabolic capillary and displacement of one liquid by another immiscible liquid in tapered or parabolic capillaries. Two possibilities are considered: (a) the narrow end of the capillary as capillary inlet and (b) the wide end of the capillary as capillary inlet. Copyright 1999 Academic Press.

  1. A viscosity prescription for a self-gravitating accretion disc

    Science.gov (United States)

    Lin, D. N. C.; Pringle, J. E.

    1987-01-01

    A model for treating the transfer of angular momentum within a gaseous differentially rotating disc subject to gravitational instability is discussed in terms of an effective kinematic viscosity. It is assumed that even when matter in the disc is subject to self-gravitation, the instability does not necessarily lead directly to condensation of parts of the disc into self-gravitating bodies. Conditions under which the present model permits a similarity solution are discussed, and it is shown that the general solution tends to the similarity solution at large times.

  2. Frequency-Dependent Viscosity of Xenon Near the Critical Point

    Science.gov (United States)

    Berg, Robert F.; Moldover, Michael R.; Zimmerli, Gregory A.

    1999-01-01

    We used a novel, overdamped oscillator aboard the Space Shuttle to measure the viscosity eta of xenon near its critical density rho(sub c), and temperature T(sub c). In microgravity, useful data were obtained within 0.1 mK of T(sub c), corresponding to a reduced temperature t = (T -T(sub c))/T(sub c) = 3 x 10(exp -7). The data extend two decades closer to T(sub c) than the best ground measurements, and they directly reveal the expected power-law behavior eta proportional to t(sup -(nu)z(sub eta)). Here nu is the correlation length exponent, and our result for the small viscosity exponent is z(sub eta) = 0.0690 +/- 0.0006. (All uncertainties are one standard uncertainty.) Our value for z(sub eta) depends only weakly on the form of the viscosity crossover function, and it agrees with the value 0.067 +/- 0.002 obtained from a recent two-loop perturbation expansion. The measurements spanned the frequency range 2 Hz less than or equal to f less than or equal to 12 Hz and revealed viscoelasticity when t less than or equal to 10(exp -1), further from T(sub c) than predicted. The viscoelasticity scales as Af(tau), where tau is the fluctuation-decay time. The fitted value of the viscoelastic time-scale parameter A is 2.0 +/- 0.3 times the result of a one-loop perturbation calculation. Near T(sub c), the xenon's calculated time constant for thermal diffusion exceeded days. Nevertheless, the viscosity results were independent of the xenon's temperature history, indicating that the density was kept near rho(sub c), by judicious choices of the temperature vs. time program. Deliberately bad choices led to large density inhomogeneities. At t greater than 10(exp -5), the xenon approached equilibrium much faster than expected, suggesting that convection driven by microgravity and by electric fields slowly stirred the sample.

  3. Viscosity Prediction of Natural Gas Using the Friction Theory

    DEFF Research Database (Denmark)

    Zeberg-Mikkelsen, Claus Kjær; Cisneros, Sergio; Stenby, Erling Halfdan

    2002-01-01

    rules based on the values of the pure component friction coefficients. Since natural gases contain mainly methane, two f-theory models are combined, where the friction coefficients of methane are estimated by a seven-constant f-theory model directly fitted to methane viscosities, and the friction...... agreement with the experimental uncertainty (+/-1.0%). The AAD is found to be higher for older measurements (around 3.5%), due mainly to the higher experimental uncertainties and problems with some of the measurements. Overall, the results are satisfactory for most industrial applications related to natural...

  4. Control of binder viscosity and hygroscopicity on particle aggregation efficiency

    Science.gov (United States)

    Mueller, Sebastian B.; Kueppers, Ulrich; Ayris, Paul M.; Jacob, Michael; Delmelle, Pierre; Dingwell, Donald B.

    2016-04-01

    In the course of explosive volcanic eruptions, large amounts of ash are released into the atmosphere and may subsequently pose a threat to infrastructure, such as aviation industry. Ash plume forecasting is therefore a crucial tool for volcanic hazard mitigation but may be significantly affected by aggregation, altering the aerodynamic properties of particles. Models struggle with the implementation of aggregation since external conditions promoting aggregation have not been completely understood; in a previous study we have shown the rapid generation of ash aggregates through liquid bonding via the use of fluidization bed technology and further defined humidity and temperature ranges necessary to trigger aggregation. Salt (NaCl) was required for the recovery of stable aggregates, acting as a cementation agent and granting aggregate cohesion. A numerical model was used to explain the physics behind particle aggregation mechanisms and further predicted a dependency of aggregation efficiency on liquid binder viscosity. In this study we proof the effect of viscosity on particle aggregation. HCl and H2SO4 solutions were diluted to various concentrations resulting in viscosities between 1 and 2 mPas. Phonolitic and rhyolitic ash samples as well as soda-lime glass beads (serving as analogue material) were fluidized in the ProCell Lab® of Glatt Ingenieurtechnik GmbH and treated with the acids via a bottom-spray technique. Chemically driven interaction between acid liquids and surfaces of the three used materials led to crystal precipitation. Salt crystals (e.g. NaCl) have been confirmed through scanning electron microscopy (SEM) and leachate analysis. Both volcanic ash samples as well as the glass beads showed a clear dependency of aggregation efficiency on viscosity of the sprayed HCl solution. Spraying H2SO4 provoked a collapse of the fluidized bed and no aggregation has been observed. This is accounted by the high hygroscopicity of H2SO4. Dissolving CaCl2 (known to be

  5. Influence of Liquid Viscosity on Droplet Impingement on Superhydrophobic Surfaces

    CERN Document Server

    Pearson, John T; Webb, Brent W

    2010-01-01

    This fluid dynamics video describes droplet impingement experiments performed on superhydrophobic surfaces. When droplets of pure water are impinged upon superhydrophobic surfaces, a region of thin coherent jets are observed for Weber numbers between 5 and 15. Also, peripheral splashing is observed for Weber numbers above about 200. When the viscosity of the droplet is increased by mixing glycerol with the water, the thin jets are not observed and peripheral splashing is delayed somewhat. In the Weber number range where pure water droplets are observed to splash peripherally, the water/glycerol droplets are observed to have two-pronged jets.

  6. Fission dynamics: The quest of a temperature dependent nuclear viscosity

    Directory of Open Access Journals (Sweden)

    Vardaci E.

    2013-12-01

    Full Text Available This contribution presents a journey within the open questions about the current use of a temperature dependent nuclear viscosity in models of nuclear fission and proposes an alternative experimental approach by using systems of intermediate fissility. This study is particularly relevant because: i systems of intermediate fissility offer a suitable framework since the intervals between the compound nucleus and scission point temperatures with increasing excitation energy are much smaller than in the case of heavier systems, ii the measurement of observables in the ER channel translates into a larger set of effective constraints for the models.

  7. A Clinical Study on Treatment of Senile Psoriasis by Replenishing Qi to Activate Blood--A Report of 40 Cases

    Institute of Scientific and Technical Information of China (English)

    刘洪普; 谭奇纹; 刘华昌

    2004-01-01

    40 cases of senile psoriasis were treated by the therapeutic principle of replenishing qi to activate blood,and the changes of T lymphocyte subgroups and indexes of haemorheology were observed. The results showed that CD4 was significantly increased, CDs significantly decreased, and the CD4/CD8 ratio significantly raised; and that the specific viscosity of whole blood at high shearing rate, and at low shearing rate, the specific viscosity of plasma, packed cell volume, and fibrinogen all significantly decreased after treatment. It is therefore concluded that the therapeutic method of replenishing qi to activate blood can exert an effect of improving immunologic function and blood circulation.

  8. Blood Typing

    Science.gov (United States)

    ... if you need repeated transfusions, as sickle cell anemia and thalassemia patients do. If blood transfusions are not closely ... the News Article Index About This Site Send Us Your Comments For ...

  9. Blood Disorders

    Science.gov (United States)

    ... people with blood disorders. Magnitude of the Problem Complications from deep vein thrombosis (DVT) kill more people each year than breast cancer, motor vehicle accidents, and HIV combined. Sickle cell trait ...

  10. What's Blood?

    Science.gov (United States)

    ... Rh" because scientists found it while studying Rhesus monkeys. If your blood is positive, you have this ... doctor. © 1995- The Nemours Foundation. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, ...

  11. Lignopolymers as viscosity-reducing additives in magnesium oxide suspensions.

    Science.gov (United States)

    Murray, Lisa R; Gupta, Chetali; Washburn, Newell R; Erk, Kendra A

    2015-12-01

    Lignopolymers are a new class of polymer additives with the capability to be used as dispersants in cementitious pastes. Made with kraft lignin cores and grafted polymer side-chains, the custom-synthesized lignopolymers were examined in terms of the molecular architecture for viscosity reducing potential in inert model suspensions. Lignin-poly(acrylic acid) (LPAA) and lignin-polyacrylamide (LPAm) have been found to vary the rheology of magnesium oxide (MgO) suspensions based on differences in chain architecture and particle-polymer interactions. A commercial comb-polymer polycarboxylate ester was compared to LPAA and LPAm at 2.7 mg/mL, a typical dosage for cement admixtures, as well as 0.25mg/mL. It was found that LPAm was a more effective viscosity reducer than both LPAA and the commercial additive at low concentrations, which was attributed to greater adsorption on the MgO particle surface and increased steric dispersion from PAm side-chain extension. The influence of chain adsorption and grafted side-chain molecular weight on rheology was also tested.

  12. Viscosity measurement of Newtonian liquids using the complex reflection coefficient.

    Science.gov (United States)

    Franco, Ediguer E; Adamowski, Julio C; Higuti, Ricardo T; Buiochi, Flávio

    2008-10-01

    This work presents the implementation of the ultrasonic shear reflectance method for viscosity measurement of Newtonian liquids using wave mode conversion from longitudinal to shear waves and vice versa. The method is based on the measurement of the complex reflection coefficient (magnitude and phase) at a solid-liquid interface. The implemented measurement cell is composed of an ultrasonic transducer, a water buffer, an aluminum prism, a PMMA buffer rod, and a sample chamber. Viscosity measurements were made in the range from 1 to 3.5 MHz for olive oil and for automotive oils (SAE 40, 90, and 250) at 15 and 22.5 degrees C, respectively. Moreover, olive oil and corn oil measurements were conducted in the range from 15 to 30 degrees C at 3.5 and 2.25 MHz, respectively. The ultrasonic measurements, in the case of the less viscous liquids, agree with the results provided by a rotational viscometer, showing Newtonian behavior. In the case of the more viscous liquids, a significant difference was obtained, showing a clear non-Newtonian behavior that cannot be described by the Kelvin-Voigt model.

  13. High viscosity fluid simulation using particle-based method

    KAUST Repository

    Chang, Yuanzhang

    2011-03-01

    We present a new particle-based method for high viscosity fluid simulation. In the method, a new elastic stress term, which is derived from a modified form of the Hooke\\'s law, is included in the traditional Navier-Stokes equation to simulate the movements of the high viscosity fluids. Benefiting from the Lagrangian nature of Smoothed Particle Hydrodynamics method, large flow deformation can be well handled easily and naturally. In addition, in order to eliminate the particle deficiency problem near the boundary, ghost particles are employed to enforce the solid boundary condition. Compared with Finite Element Methods with complicated and time-consuming remeshing operations, our method is much more straightforward to implement. Moreover, our method doesn\\'t need to store and compare to an initial rest state. The experimental results show that the proposed method is effective and efficient to handle the movements of highly viscous flows, and a large variety of different kinds of fluid behaviors can be well simulated by adjusting just one parameter. © 2011 IEEE.

  14. Effect of combined treatments on viscosity of whey dispersions

    Energy Technology Data Exchange (ETDEWEB)

    Camillo, A.; Sabato, S.F. E-mail: sfsabato@ipen.br

    2004-10-01

    Whey proteins, enriched protein fractions from milk, are of great interest as ingredients due to nutritional value associated with its functional properties. These proteins could have their structural properties improved when some treatments are applied, such as thermal and gamma irradiation or when some compounds are added. The current work aimed to study the viscometer behavior of whey dispersions submitted to two different combined treatments: (1) thermal plus irradiation and (2) thermal plus vacuum and N{sub 2} plus irradiation. Dispersions of whey protein in water (5% and 8% protein (w/v) base) and containing proteins and glycerol at ratios 1:1 and 2:1 (protein:glycerol) were submitted to both combined treatments. The irradiation doses were 0, 5, 15 and 25 kGy. The viscosity of the two combined treatments and for four levels of absorbed doses is presented and the combined effects are discussed. The thermal treatment combined with gamma irradiation contributed to increase the viscosity as irradiation doses increases for both (5% and 8%) concentrations of proteins (p<0.05). For protein and glycerol solutions, the irradiation dose seemed to result in a slightly increase. The vacuum applied before the irradiation showed a small contribution.

  15. Empirical slip and viscosity model performance for microscale gas flows.

    Energy Technology Data Exchange (ETDEWEB)

    Gallis, Michail A.; Boyd, Iain D. (University of Michigan, Ann Arbor, MI); McNenly, Matthew J. (University of Michigan, Ann Arbor, MI)

    2004-07-01

    For the simple geometries of Couette and Poiseuille flows, the velocity profile maintains a similar shape from continuum to free molecular flow. Therefore, modifications to the fluid viscosity and slip boundary conditions can improve the continuum based Navier-Stokes solution in the non-continuum non-equilibrium regime. In this investigation, the optimal modifications are found by a linear least-squares fit of the Navier-Stokes solution to the non-equilibrium solution obtained using the direct simulation Monte Carlo (DSMC) method. Models are then constructed for the Knudsen number dependence of the viscosity correction and the slip model from a database of DSMC solutions for Couette and Poiseuille flows of argon and nitrogen gas, with Knudsen numbers ranging from 0.01 to 10. Finally, the accuracy of the models is measured for non-equilibrium cases both in and outside the DSMC database. Flows outside the database include: combined Couette and Poiseuille flow, partial wall accommodation, helium gas, and non-zero convective acceleration. The models reproduce the velocity profiles in the DSMC database within an L{sub 2} error norm of 3% for Couette flows and 7% for Poiseuille flows. However, the errors in the model predictions outside the database are up to five times larger.

  16. Effect of combined treatments on viscosity of whey dispersions

    Science.gov (United States)

    Camillo, A.; Sabato, S. F.

    2004-09-01

    Whey proteins, enriched protein fractions from milk, are of great interest as ingredients due to nutritional value associated with its functional properties. These proteins could have their structural properties improved when some treatments are applied, such as thermal and gamma irradiation or when some compounds are added. The current work aimed to study the viscometer behavior of whey dispersions submitted to two different combined treatments: (1) thermal plus irradiation and (2) thermal plus vacuum and N 2 plus irradiation. Dispersions of whey protein in water (5% and 8% protein (w/v) base) and containing proteins and glycerol at ratios 1:1 and 2:1 (protein:glycerol) were submitted to both combined treatments. The irradiation doses were 0, 5, 15 and 25 kGy. The viscosity of the two combined treatments and for four levels of absorbed doses is presented and the combined effects are discussed. The thermal treatment combined with gamma irradiation contributed to increase the viscosity as irradiation doses increases for both (5% and 8%) concentrations of proteins ( p<0.05). For protein and glycerol solutions, the irradiation dose seemed to result in a slightly increase. The vacuum applied before the irradiation showed a small contribution.

  17. Effect of Short Chain Alcohols upon Viscosity of TTAB Solution

    Institute of Scientific and Technical Information of China (English)

    Yun-fei Yan; Hua-zhen Li; Hai-yang Yang; Jia-sheng Qian; Ping-ping Zhu; Ping-sheng He

    2008-01-01

    The effect of ethanol (C2H5OH),propanol (C3H7OH),and butanol (C4H9OH) upon the viscosity of tetrade- cyltrimethylammonium bromide (TTAB) solution in the presence or absence of KBr at 30℃ was investi- gated,where the surfactant concentration Cs is kept constant.In the absence of KBr,the relative viscosity ηr of TTAB solution increases linearly with the alcohol concentration CA,indicating that the alcohols do not promote micelle formation of TTAB.In the presence of KBr,ηr linearly decreases with CA for C2H5OH, but it exhibits a maximum with increasing CA for C3H7OH or C4H9OH.The facts reveal that C2H5OH or C4H9OH promotes the micelle formation of TTAB.A possible explanation is that the hydrophobicity of the micellar interior is enhanced by KBr,so that C2H5OH or C4H9OH can dissolve in micelle and promotes micelle formation.In the presence of KCl,which is less efficient in promoting the micelle formation of cationic surfactant,both C3H7OH and C4H9OH have only a slight effect on the micelle formation.In contrast,due to the hydrophilicity,C2H5OH cannot dissolve in micelles in the presence of KBr or KCl.

  18. Viscosity and dissipative hydrodynamics from effective field theory

    Science.gov (United States)

    Grozdanov, Sašo; Polonyi, Janos

    2015-05-01

    With the goal of deriving dissipative hydrodynamics from an action, we study classical actions for open systems, which follow from the generic structure of effective actions in the Schwinger-Keldysh closed-time-path (CTP) formalism with two time axes and a doubling of degrees of freedom. The central structural feature of such effective actions is the coupling between degrees of freedom on the two time axes. This reflects the fact that from an effective field theory point of view, dissipation is the loss of energy of the low-energy hydrodynamical degrees of freedom to the integrated-out, UV degrees of freedom of the environment. The dynamics of only the hydrodynamical modes may therefore not possess a conserved stress-energy tensor. After a general discussion of the CTP effective actions, we use the variational principle to derive the energy-momentum balance equation for a dissipative fluid from an effective Goldstone action of the long-range hydrodynamical modes. Despite the absence of conserved energy and momentum, we show that we can construct the first-order dissipative stress-energy tensor and derive the Navier-Stokes equations near hydrodynamical equilibrium. The shear viscosity is shown to vanish in the classical theory under consideration, while the bulk viscosity is determined by the form of the effective action. We also discuss the thermodynamics of the system and analyze the entropy production.

  19. BV solutions and viscosity approximations of rate-independent systems

    CERN Document Server

    Mielke, Alexander; Savare', Giuseppe

    2009-01-01

    In the nonconvex case solutions of rate-independent systems may develop jumps as a function of time. To model such jumps, we adopt the philosophy that rate independence should be considered as limit of systems with smaller and smaller viscosity. For the finite-dimensional case we study the vanishing-viscosity limit of doubly nonlinear equations given in terms of a differentiable energy functional and a dissipation potential which is a viscous regularization of a given rate-independent dissipation potential. The resulting definition of 'BV solutions' involves, in a nontrivial way, both the rate-independent and the viscous dissipation potential, which play a crucial role in the description of the associated jump trajectories. We shall prove a general convergence result for the time-continuous and for the time-discretized viscous approximations and establish various properties of the limiting BV solutions. In particular, we shall provide a careful description of the jumps and compare the new notion of solutions ...

  20. Hubble parameter in QCD Universe for finite bulk viscosity

    Energy Technology Data Exchange (ETDEWEB)

    Tawfik, A.; Wahba, M. [Egyptian Center for Theoretical Physics (ECTP), MTI University, Al Mukattam, Cairo 11212 (Egypt); Mansour, H. [Department of Physics, Cairo University, Giza (Egypt); Harko, T. [Department of Physics and Center for Theoretical and Computational Physics, The University of Hong Kong, Pok Fu Lam Road, Hong Kong (China)

    2010-12-01

    We consider the influence of the perturbative bulk viscosity on the evolution of the Hubble parameter in the QCD era of the early Universe. For the geometry of the Universe we assume the homogeneous and isotropic Friedmann-Lemaitre-Robertson-Walker metric, while the background matter is assumed to be characterized by barotropic equations of state, obtained from recent lattice QCD simulations, and heavy-ion collisions, respectively. Taking into account a perturbative form for the bulk viscosity coefficient, we obtain the evolution of the Hubble parameter, and we compare it with its evolution for an ideal (non-viscous) cosmological matter. A numerical solution for the viscous QCD plasma in the framework of the causal Israel-Stewart thermodynamics is also obtained. Both the perturbative approach and the numerical solution qualitatively agree in reproducing the viscous corrections to the Hubble parameter, which in the viscous case turns out to be slightly different as compared to the non-viscous case. Our results are strictly limited within a very narrow temperature- or time-interval in the QCD era, where the quark-gluon plasma is likely dominant. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Lovelock theories, holography and the fate of the viscosity bound

    CERN Document Server

    Camanho, Xian O; Paulos, Miguel F

    2010-01-01

    We consider Lovelock theories of gravity in the context of AdS/CFT. We show that, for these theories, causality violation on a black hole background can occur well in the interior of the geometry, thus posing more stringent constraints than were previously found in the literature. Also, we find that instabilities of the geometry can appear for certain parameter values at any point in the geometry, as well in the bulk as close to the horizon. These new sources of causality violation and instability should be related to CFT features that do not depend on the UV behavior. They solve a puzzle found previously concerning unphysical negative values for the shear viscosity that are not ruled out solely by causality restrictions. We find that, contrary to previous expectations, causality violation is not always related to positivity of energy. Furthermore, we compute the bound for the shear viscosity to entropy density ratio of supersymmetric conformal field theories from d=4 till d=10 - i.e., up to quartic Lovelock ...

  2. Viscosity sinergism of hydrozypropmethyl and carboxy methyl cellulose

    Directory of Open Access Journals (Sweden)

    Katona Jaroslav M.

    2008-01-01

    Full Text Available Rheology modifiers are common constituents of food, cosmetic and pharmaceutic products. Often, by using two or more of them, better control of the product rheological properties can be achieved. In this work, rheological properties of hydroxypropymethyl cellulose (HPMC and sodium carboxymethyl cellulose (NaCMC solutions of different concentrations were investigated and compared to the flow properties of 1% HPMC/NaCMC binary mixtures at various HPMC/NaCMC mass ratios. Solutions of HPMC and NaCMC were found to be pseudoplastic, where pseudoplasticity increases with increase in the macromolecules concentration. Changes of the degree of pseudoplasticity, n as well as the coefficient of consistency, K with the concentration are more pronounced in HPMC solutions when compared to the NaCMC ones. This is mostly due to the ability of HPMC molecules to associate with each other at concentrations above critical overlap concentration, c , and greater flexibility of macromolecular chains. Binary mixtures of HPMC/NaCMC were also found to be pseudoplastic. Experimentally obtained viscosities of the mixture were proved to be larger than theoretically expected ones, indicating viscosity synergism as a consequence of HPMC-NaCMC interaction. Maximum in synergy was observed when HPMC/NaCMC mass ratio was 0.4/0.6, no matter of the shear rate applied. On the other hand, it was found that relative positive deviation, RPD decreases when shear rate is increased.

  3. Artificial blood.

    OpenAIRE

    1983-01-01

    #Blood substitutes have been developed for almost a century. The various type of artificial blood was continuously available on the market. The theme of this report is to identify the best substitute in emergency situation for some patients and science students. The definition of best is given; thus, as the vital part of the report, the comparison between them is described and discussed. Modified hemoglobin, bovine-based hemoglobin and PFCs are three basic types. In terms of the perfor...

  4. Synthesize and application of the oil-soluble viscosity reducer in heavy oil

    Energy Technology Data Exchange (ETDEWEB)

    Zhihong, Zhang; Yun, Huang [Northwest Oilfield Branch Engineering and Technology Institute of Sinopec (China); Jixiang, Guo; Heyi, Wang; Kai, Chao [Enhanced Oil Recovery Research Center, China University of Petroleum (China)], email: guojx002@163.com

    2010-07-01

    When viscosity reducer is added to crude oil, it breaks its original structure and reduces oil viscosity. A polybasic copolymer oil-soluble viscosity reducer of heavy oil was synthesized by using the orthogonal method. Infrared spectra (IR) and interfacial tensions of heavy oil with or without viscosity reducer were investigated. The synthetic viscosity reducer was added to a biphasic heavy oil/water solution, and the interfacial tension between the oil and the water was measured. The interfacial tension was significantly lower than the interfacial tension of a heavy oil/water solution without the viscosity reducer. It was observed that the viscosity reducer spread from the oil phase to the oil-water interface; it could replace macromolecular active substances of the oil-water interface so that a new interfacial film could be formed, thus reducing the interfacial tension. This synthetic viscosity reducer is more efficient than commercialy available viscosity reducers; its viscosity reduction rate is up to 95.47% at 50 degree Celsius.

  5. Evaluation of Viscosity Characteristics of Spin-Coated UV Nanoimprint Resin

    Science.gov (United States)

    Hidemasa Atobe,; Hiroshi Hiroshima,; Qing Wang,

    2010-06-01

    The viscosity of a UV-curable resin used in UV nanoimprint is one of the key parameters to determine the process speed of resin filling in the recesses of a mold. We have developed an apparatus to measure the viscosity of a spin-coated thin liquid film on a wafer. With this viscosity measuring apparatus we examined the effect of the film thickness, exposure of resin to atmosphere, and temperature of resin on the viscosity of PAK-01, which is a UV-curable resin commonly employed in UV nanoimprint. The viscosity of this resin with its film thickness larger than 2.3 μm showed a constant value of 83 mPa\\cdots, which is almost the same as that of the bulk PAK-01. At below 2.3 μm, the viscosity seemed to increase with decreasing film thickness. The viscosity of the spin-coated resin was also found to increase with the duration of its exposure to atmosphere; for a 30 min exposure to atmosphere, the viscosity reached up to 461 mPa\\cdots. It is considered that during the prolonged exposure, the volatile component of the resin evaporated. When subjected to heat treatment, the viscosity of the UV-curable resin did not seem to depend on film thickness and maintained a steady value of 385 mPa\\cdots. It was found that as the film thickness decreased the viscosity approached the value obtained by heat treatment.

  6. Dilute bird nectars: viscosity constrains food intake by licking in a sunbird.

    Science.gov (United States)

    Köhler, Angela; Leseigneur, Carolina D C; Verburgt, Luke; Nicolson, Susan W

    2010-10-01

    Floral nectars of bird-pollinated plants are relatively dilute. One hypothesis proposed to explain this concerns the difficulty for birds of drinking nectar of high viscosity. We examined the effects of viscosity, separately from those of sugar concentration, on feeding by captive whitebellied sunbirds (Cinnyris talatala). Viscosities of artificial nectar (sucrose solutions ranging in concentration from 0.25 to 1.5 mol/l) were altered with Tylose, an inert polysaccharide. Food consumption was measured over 3 h, and lick frequency and duration were recorded using photodetection devices on feeding apertures too small for the bill but large enough for the extended tongue. Volumetric intake rates (ml/s) were inversely proportional to nectar viscosity, and were similar over the range of sucrose concentrations when viscosity was held constant. Sucrose intake rates (mg/s) remained the same on pure sucrose solutions, but they decreased with increasing viscosity at a constant sucrose concentration. Lick frequencies and tongue loads were reduced at high viscosities, and lick duration increased, which confirms that sunbirds take longer to ingest viscous solutions. Licking behavior was remarkably similar in birds feeding on different sucrose concentrations if viscosity was held constant. Nectar ingestion rate is determined by viscosity; however, total food intake is mainly modulated by sugar concentration. Similar effects of food viscosity have been observed in insects that suck nectar.

  7. The role of bulk viscosity on the decay of compressible, homogeneous, isotropic turbulence

    Science.gov (United States)

    Johnsen, Eric; Pan, Shaowu

    2016-11-01

    The practice of neglecting bulk viscosity in studies of compressible turbulence is widespread. While exact for monatomic gases and unlikely to strongly affect the dynamics of fluids whose bulk-to-shear viscosity ratio is small and/or of weakly compressible turbulence, this assumption is not justifiable for compressible, turbulent flows of gases whose bulk viscosity is orders of magnitude larger than their shear viscosities (e.g., CO2). To understand the mechanisms by which bulk viscosity and the associated phenomena affect compressible turbulence, we conduct DNS of freely decaying compressible, homogeneous, isotropic turbulence for ratios of bulk-to-shear viscosity ranging from 0-1000. Our simulations demonstrate that bulk viscosity increases the decay rate of turbulent kinetic energy; while enstrophy exhibits little sensitivity to bulk viscosity, dilatation is reduced by an order of magnitude within the two eddy turnover time. Via a Helmholtz decomposition of the flow, we determined that bulk viscosity damps the dilatational velocity and reduces dilatational-solenoidal exchanges, as well as pressure-dilatation coupling. In short, bulk viscosity renders compressible turbulence incompressible by reducing energy transfer between translational and internal modes.

  8. Nanoliter viscometer for analyzing blood plasma and other liquid samples.

    Science.gov (United States)

    Srivastava, Nimisha; Davenport, Robertson D; Burns, Mark A

    2005-01-15

    We have developed a microfabricated nanoliter capillary viscometer that quickly, easily, and inexpensively measures the viscosity of liquids. The measurement of viscosity is based on capillary pressure-driven flow inside microfluidic channels (depth approximately 30 microm and width approximately 300 microm). Accurate and precise viscosity measurements can be made in less than 100 s while using only 600 nL of liquid sample. The silicon-glass hybrid device (18 mm by 15 mm) contains on-chip components that measure the driving capillary pressure difference and the relevant geometrical parameters; these components make the nanoliter viscometer completely self-calibrating, robust, and easy to use. Several different microfabricated viscometers were tested using solutions with viscosities ranging from 1 to 5 cP, a range relevant to biological fluids (urine, blood, blood plasma, etc.). Blood plasma samples collected from patients with the symptoms of hyperviscosity syndrome were tested on the nanoliter capillary viscometer to an accuracy of 3%. Such self-calibrating nanoliter viscometers may have widespread applications in chemical, biological, and medical laboratories as well as in personal health care.

  9. Blood Transfusion and Donation

    Science.gov (United States)

    ... receiving the blood transfusion. To keep blood safe, blood banks carefully screen donated blood. The risk of catching ... one or more times before the surgery. A blood bank will store your blood for your use. NIH: ...

  10. Blood (For Parents)

    Science.gov (United States)

    ... Old Feeding Your 1- to 2-Year-Old Blood KidsHealth > For Parents > Blood A A A What's ... about the mysterious, life-sustaining fluid called blood. Blood Basics Two types of blood vessels carry blood ...

  11. Catecholamine blood test

    Science.gov (United States)

    Norepinephrine -- blood; Epinephrine -- blood; Adrenalin -- blood; Dopamine -- blood ... A blood sample is needed. ... the test. This is especially true if both blood and urine catecholamines are to be measured. You ...

  12. Biology of Blood

    Science.gov (United States)

    ... here for the Professional Version Home Blood Disorders Biology of Blood Overview of Blood Resources In This ... Version. DOCTORS: Click here for the Professional Version Biology of Blood Overview of Blood Components of Blood ...

  13. Blood Clotting and Pregnancy

    Medline Plus

    Full Text Available ... Blood Basics Blood Disorders Anemia Bleeding Disorders Blood Cancers Blood Clots Blood Clotting and Pregnancy Clots and ... Increased maternal age Other medical illness (e.g., cancer, infection) back to top How are Blood Clots ...

  14. Effects of aortic irregularities on blood flow.

    Science.gov (United States)

    Prahl Wittberg, Lisa; van Wyk, Stevin; Fuchs, Laszlo; Gutmark, Ephraim; Backeljauw, Philippe; Gutmark-Little, Iris

    2016-04-01

    Anatomic aortic anomalies are seen in many medical conditions and are known to cause disturbances in blood flow. Turner syndrome (TS) is a genetic disorder occurring only in females where cardiovascular anomalies, particularly of the aorta, are frequently encountered. In this study, numerical simulations are applied to investigate the flow characteristics in four TS patient- related aortic arches (a normal geometry, dilatation, coarctation and elongation of the transverse aorta). The Quemada viscosity model was applied to account for the non-Newtonian behavior of blood. The blood is treated as a mixture consisting of water and red blood cells (RBC) where the RBCs are modeled as a convected scalar. The results show clear geometry effects where the flow structures and RBC distribution are significantly different between the aortas. Transitional flow is observed as a jet is formed due to a constriction in the descending aorta for the coarctation case. RBC dilution is found to vary between the aortas, influencing the WSS. Moreover, the local variations in RBC volume fraction may induce large viscosity variations, stressing the importance of accounting for the non-Newtonian effects.

  15. Investigating the effect of lateral viscosity variations in the Earth's mantle

    Science.gov (United States)

    O'Farrell, K. A.; Lithgow-Bertelloni, C. R.

    2015-12-01

    Seismic tomography can be used to investigate radial viscosity variations on instantaneous flow models by predicting the global geoid and comparing with the observed geoid. This method is one of many that has been used to constrain viscosity structure in the Earth's mantle in the last few decades. Using the 3D mantle convection model, Stag-YY (e.g., Hernlund and Tackley, 2008), we are further able to explore the effect of lateral variations in viscosity in addition to the radial variations. Examining over 50 tomographic models we found notable differences by comparing a synthetically produced geoid with the observed geoid. Comparing S- and P-wave tomographic models, the S-wave models provided a better fit to the observed geoid. Using this large suite of 50 tomographic models, we have been able to constrain the radial viscosity structure of the Earth. We found that two types of viscosity profiles yielded equally good fits. A viscosity profile with a low transition zone viscosity and a lower mantle viscosity equal to the upper mantle, or a profile with a large lower mantle viscosity and a transition zone viscosity similar to the upper mantle. Using the set of radial viscosity profiles that gave the best fit to the observed geoid, we can explore a range of lateral viscosity variations and see how they affect the different types of tomographic models. Improving on previous studies of lateral viscosity variations (e.g. Ghosh, Becker and Zhong, 2010), we systematically explore a large range of tomographic models and density-velocity conversion factors. We explore which type of tomographic model (S- or P- wave) is more strongly affected by lateral viscosity variations, as well as the effect on isotropic and anisotropic models. We constrain the strength of lateral viscosity variations necessary to produce a high correlation between observed and predicted geoid anomalies. We will discuss the wavelength of flow that is most affected by the lateral viscosity variations

  16. Energy Dissipation and Apparent Viscosity of Semi-solid Metal during Rheological Processes Part Ⅱ: Apparent Viscosity

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This study investigated the rheological properties of semi-solid metal. An analytical model of apparent viscosity was built up based on analysis of energy dissipation during rheological processes such as slurry preparing,delivering and model filling. The rheological properties of SSM (semi-solid metal) slurry was described by an analytical model in terms of microstructural parameters, which consist of effective solid fraction, particle size and shape, and flow parameters such as mean velocity, fluctuant velocity and relative velocity between liquid and solid phase. The model was verified in the experiment of A356 alloys with a coaxial double-bucket rheometer. And the maximum relative error between the theoretical value and measured one is less than 10%.The results of experiment and theoretical calculation also indicate that the microstructural parameters and flow parameters are two major factors that affect the apparent viscosity of semi-solid alloys, and fluctuant velocity and relative velocity between liquid and solid phase are the key factors to distinguish between steady and transient rheological properties.

  17. "Coulombic Viscosity" In Granular Materials: Planetary and Astrophysical Implications

    Science.gov (United States)

    Marshall, J. R.

    1999-09-01

    The term "Coulombic viscosity" is introduced here to define an empirically observed phenomenon from experiments conducted in both microgravity, and in ground-based 1-g conditions. In the latter case, a sand attrition device was employed to test the longevity of aeolian materials by creating two intersecting grain-circulation paths or cells that would lead to most of the grain energy being expended on grain-to-grain collisions (simulating dune systems). In the areas in the device where gravitationally-driven grain-slurries recycled the sand, the slurries moved with a boundary-layer impeded motion down the chamber walls. Excessive electrostatic charging of the grains during these experiments was prevented by the use of an a.c. corona (created by a Tesla coil) through which the grains passed on every cycle. This created both positive and negative ions which neutralized the triboelectrically-generated grain charges. When the corona was switched on, the velocity of the wall-attached slurries increased by a factor of two as approximately determined by direct observation. What appeared to be a freely-flowing slurry of grains impeded only by intergranular mechanical friction, had obviously been significantly retarded in its motion by electrostatic forces between the grains; with the charging reduced, the grains were able to move past one another without a flow "viscosity" imposed by the Coulombic intergranular forces. A similar phenomenon was observed during microgravity experiments aboard Space Shuttle in USML-1 & USML-2 spacelabs where freely-suspended clouds of sand were being investigated for their potential to for-m aggregates. In this environment, the grains were also charged electrostatically (by natural processes prior to flight), but were free from the intervention of gravity in their interactions. The grains were dispersed into dense clouds by bursts of air turbulence and allowed to form aggregates as the ballistic and turbulent motions damped out. During this

  18. Managing your blood sugar

    Science.gov (United States)

    Hyperglycemia - control; Hypoglycemia - control; Diabetes - blood sugar control; Blood glucose - managing ... Know how to: Recognize and treat low blood sugar (hypoglycemia) Recognize and treat high blood sugar (hyperglycemia) ...

  19. Gas transport and vesicularity in low-viscosity liquids

    Science.gov (United States)

    Pioli, Laura; Bonadonna, Costanza; Abdulkareem, Lokman; Azzopardi, Barry; Phillips, Jeremy

    2010-05-01

    Vesicle textures of basaltic scoria preserve information on magma bubble content at fragmentation and are commonly used to constrain degassing, vesiculation and magma permeability. These studies are based on the assumption that microscale textures are representative of the conduit-scale structures and processes. However, the conditions for which this assumption is valid have not been investigated in detail. We have investigated conduit-scale structures by performing a series of experiments of separate two-phase flows in a 6.5-m high cylindrical bubble column using a combination of air with pure glucose syrup, water-syrup mixtures and pure water to reproduce open-system degassing and strombolian activity conditions in the upper volcanic conduit (i.e. at very low or zero liquid fluxes). We have varied gas fluxes, initial liquid height, gas inlet configuration and liquid viscosity and analyzed flow regimes and properties. Temperature and pressure were measured at several heights along the pipe and vesicularity was calculated using pressure data, liquid level measurements and an Electrical Capacitance tomography (ECT) system, which measures instantaneous vesicularity and phase distribution from capacitance measurements between pairs of electrodes placed uniformly around the pipe circumference. The aim of the experiments was to identify the effect of gas-flow rates on the flow regimes (i.e. bubbly, slug, churn and annular), the main degassing structures and the total gas content of the column. The effect of increasing and decreasing gas flow rates was also studied to check hysteresis effects. Results indicate that the vesicularity of the liquid column depends primarily on gas flux, whereas flow regimes exert a minor control. In fact, vesicularity increases with gas flux following a power-law trend whose exponent depends on the viscosity of the liquid. In addition, distributions of instantaneous gas fraction in the column cross section during syrup experiments have shown

  20. Viscosity of magnetite–toluene nanofluids: Dependence on temperature and nanoparticle concentration

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Rahul [Department of Mechanical Engineering, Iowa State University, Ames, IA (United States); Sanchez, Oswaldo [Department of Mathematical Sciences, Morningside College, Sioux City, IA (United States); Ghosh, Suvojit [Department of Engineering Physics, McMaster University, Hamilton, ON (Canada); Kadimcherla, Naveen [Department of Mechanical Engineering, Iowa State University, Ames, IA (United States); Sen, Swarnendu [Department of Mechanical Engineering, Jadavpur University, Kolkata, West Bengal (India); Balasubramanian, Ganesh, E-mail: bganesh@iastate.edu [Department of Mechanical Engineering, Iowa State University, Ames, IA (United States)

    2015-10-23

    Highlights: • Viscosity of magnetite in toluene nanofluid increases monotonically with particle concentration. • Clusters formed at higher particle concentration are monodisperse. • With increasing temperature, viscosity decreases due less fraction of immobile fluid molecules. - Abstract: We examine the dependence of the viscosity of nanofluids, comprised of magnetite nanoparticles dispersed in toluene, on particle concentration and temperature. The nanofluid viscosity increases monotonically with particle concentration. We show that although the nanoparticles aggregate to form clusters with increasing concentration, the cluster size is fairly monodisperse and hence the viscosity can be expressed as a function of only the particle concentration. The viscosity of the nanofluid is found to decrease with temperature, similarly to the characteristics of the carrier liquid. We describe these dependencies through an empirical correlation, since the observations are useful to employ such nanofluids in engineering applications.

  1. Viscosity of multi-component molten nitrate salts : liquidus to 200 degrees C.

    Energy Technology Data Exchange (ETDEWEB)

    Bradshaw, Robert W.

    2010-03-01

    The viscosity of molten salts comprising ternary and quaternary mixtures of the nitrates of sodium, potassium, lithium and calcium was determined experimentally. Viscosity was measured over the temperature range from near the relatively low liquidus temperatures of he individual mixtures to 200C. Molten salt mixtures that do not contain calcium nitrate exhibited relatively low viscosity and an Arrhenius temperature dependence. Molten salt mixtures that contained calcium nitrate were relatively more viscous and viscosity increased as the roportion of calcium nitrate increased. The temperature dependence of viscosity of molten salts containing calcium nitrate displayed curvature, rather than linearity, when plotted in Arrhenius format. Viscosity data for these mixtures were correlated by the Vogel-Fulcher- ammann-Hesse equation.

  2. The role of fat in flavor perception: effect of partition and viscosity in model emulsions.

    Science.gov (United States)

    Bayarri, Sara; Taylor, Andrew J; Hort, Joanne

    2006-11-15

    Decreasing the fat content of a food, while maintaining the same aroma content, changes both aroma release (due to partition effects) and the viscosity of the food. To understand the relative contribution of these two factors on flavor perception, a series of flavored emulsions were prepared to control aroma release and viscosity using different aroma, oil, and hydroxypropyl methyl cellulose (HPMC) contents. Samples were formulated to deliver the same aroma-release in vitro and in vivo, and their viscosity was measured using the Kokini oral shear stress parameter. Despite the in vivo aroma release being constant, there were perceptual differences between the samples, and the flavor intensity decreased as in-mouth viscosity increased. For these iso release samples, the Kokini oral shear stress parameter correlated well with the decrease in perception, suggesting that there may be a viscosity stimulus or that the viscosity affects release of tastant and hinders aroma-taste interactions.

  3. Microvascular blood flow resistance: Role of red blood cell migration and dispersion.

    Science.gov (United States)

    Katanov, Dinar; Gompper, Gerhard; Fedosov, Dmitry A

    2015-05-01

    Microvascular blood flow resistance has a strong impact on cardiovascular function and tissue perfusion. The flow resistance in microcirculation is governed by flow behavior of blood through a complex network of vessels, where the distribution of red blood cells across vessel cross-sections may be significantly distorted at vessel bifurcations and junctions. In this paper, the development of blood flow and its resistance starting from a dispersed configuration of red blood cells is investigated in simulations for different hematocrit levels, flow rates, vessel diameters, and aggregation interactions between red blood cells. Initially dispersed red blood cells migrate toward the vessel center leading to the formation of a cell-free layer near the wall and to a decrease of the flow resistance. The development of cell-free layer appears to be nearly universal when scaled with a characteristic shear rate of the flow. The universality allows an estimation of the length of a vessel required for full flow development, lc ≲ 25D, for vessel diameters in the range 10 μm red blood cell dispersion at vessel bifurcations and junctions on the flow resistance may be significant in vessels which are shorter or comparable to the length lc. Aggregation interactions between red blood cells generally lead to a reduction of blood flow resistance. The simulations are performed using the same viscosity for both external and internal fluids and the RBC membrane viscosity is not considered; however, we discuss how the viscosity contrast may affect the results. Finally, we develop a simple theoretical model which is able to describe the converged cell-free-layer thickness at steady-state flow with respect to flow rate. The model is based on the balance between a lift force on red blood cells due to cell-wall hydrodynamic interactions and shear-induced effective pressure due to cell-cell interactions in flow. We expect that these results can also be used to better understand the flow

  4. Viscosity of carbon nanotube suspension using artificial neural networks with principal component analysis

    Science.gov (United States)

    Yousefi, Fakhri; Karimi, Hajir; Mohammadiyan, Somayeh

    2016-11-01

    This paper applies the model including back-propagation network (BPN) and principal component analysis (PCA) to estimate the effective viscosity of carbon nanotubes suspension. The effective viscosities of multiwall carbon nanotubes suspension are examined as a function of the temperature, nanoparticle volume fraction, effective length of nanoparticle and the viscosity of base fluids using artificial neural network. The obtained results by BPN-PCA model have good agreement with the experimental data.

  5. The Effect of Fluorocarbon Surfactant Additives on the Effective Viscosity of Acetone Solutions of Cellulose Diacetate,

    Science.gov (United States)

    2014-09-26

    34 FOREIGN TECHNOLOGY DIVISION i00 Lfl .. THE EFFECT OF FLUOROCARBON SURFACTANT ADDITIVES ON THE EFFECTIVE VISCOSITY OF ACETONE SOLUTIONS OF CELLULOSE ...ADDITIVES ON TH~ .. t- ’_ ition EFFECTIVE VISCOSITY OF ACETONE SOLUTIONS OF CELLULOSE DIACETATE D~rbt~l By: L.A. Shits, N. Yu. Kal’nova Codesuton English...VISCOSITY OF ACETONE SOLUTIONS OF CELLULOSE DIACETATE L. A. Shits, N. Yu. Kal’nova (Institute of Physical Chemistry of the AS USSR, Moscow) ! - The

  6. Photoinduced aging and viscosity evolution in Se-rich Ge-Se glasses

    Energy Technology Data Exchange (ETDEWEB)

    Gueguen, Yann; Sangleboeuf, Jean-Christophe; Rouxel, Tanguy [LARMAUR ERL CNRS 6274, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex (France); King, Ellyn A.; Lucas, Pierre [Department of Materials Science and Engineering, University of Arizona, 4715 E. Fort Lowell Road, Tucson, Arizona 85712 (United States); Keryvin, Vincent [LIMATB EA 4250, Université de Bretagne Sud, Rue de Saint Maudé, 56321 Lorient Cedex (France); Bureau, Bruno [Equipe Verres et Céramiques, UMR-CNRS 6226 Sciences Chimiques de Rennes, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex (France)

    2013-08-21

    We propose here to investigate the non-equilibrium viscosity of Ge-Se glasses under and after light irradiation. Ge{sub 10}Se{sub 90} and Ge{sub 20}Se{sub 80} fibers have been aged in the dark and under ambient light, over months. During aging, both the relaxation of enthalpy and the viscosity have been investigated. The viscosity was measured by shear relaxation-recovery tests allowing the measurement of non-equilibrium viscosity. When Ge{sub 10}Se{sub 90} glass fibers are aged under irradiation, a relatively fast fictive temperature decrease is observed. Concomitantly, during aging under irradiation, the non-equilibrium viscosity increases and reaches an equilibrium after two months of aging. This viscosity increase is also observed in Ge{sub 20}Se{sub 80} fibers. Nevertheless, this equilibrium viscosity is far below the viscosity expected at the configurational equilibrium. As soon as the irradiation ceases, the viscosity increases almost instantaneously by about one order of magnitude. Then, if the fibers are kept in the dark, their viscosity slowly increases over months. The analysis of the shear relaxation functions shows that the aging is thermorheologically simple. On the other side, there is no simple relaxation between the shear relaxation functions measured under irradiation and those measured in the dark. These results clearly suggest that a very specific photoinduced aging process occurs under irradiation. This aging is due to photorelaxation. Nevertheless, the viscosity changes are not solely correlated to photoaging and photorelaxation. A scenario is proposed to explain all the observed viscosity evolutions under and after irradiation, on the basis of photoinduced transient defects.

  7. Liquid-Liquid Structure Transition in Metallic Melts: Experimental Evidence by Viscosity Measurement

    Institute of Scientific and Technical Information of China (English)

    WANG Yu-Qing; WU Yu-Qin; BIAN Xiu-Fang

    2007-01-01

    Temperature dependence of viscosity for more than ten kinds of metallic melts is analysed based on viscosity measurements. An obvious turning point is observed on the Arrhenius curves. Since viscosity is one of the physical properties sensitive to structure, its discontinuous change with temperature reveals the possible liquidliquid structure transition in the metallic melts. Furthermore, an integrated liquid structure transition diagram of the Sn-Bi system is presented. The universality of liquid-liquid structure transition is also discussed simply.

  8. Advances of Studies on Mechanisms of Drugs for Activating Blood Circulation and Removing Blood Stasis in Treatment of Primary Liver Cancer

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ Primary liver cancer is mainly characterized by the mass in hypochondriac region, stabbing pain at a fixative region, tenderness, dim complexion,vascular spider, vein exposure, livid tongue,ecchymosis, taut and uneven pulse and other symptoms of blood stasis. Experimental studies have found that the patient with liver cancer is often accompanied with disturbance of microcirculation,increase of blood viscosity and high blood agglutinative state. Therefore, activating blood circulation to remove blood stasis is clinically an important therapy for primary liver cancer. A great number of studies on the mechanisms have been carried out in China and other countries. The follow is a review about the mechanisms.

  9. Black strings, low viscosity fluids, and violation of cosmic censorship.

    Science.gov (United States)

    Lehner, Luis; Pretorius, Frans

    2010-09-03

    We describe the behavior of 5-dimensional black strings, subject to the Gregory-Laflamme instability. Beyond the linear level, the evolving strings exhibit a rich dynamics, where at intermediate stages the horizon can be described as a sequence of 3-dimensional spherical black holes joined by black string segments. These segments are themselves subject to a Gregory-Laflamme instability, resulting in a self-similar cascade, where ever-smaller satellite black holes form connected by ever-thinner string segments. This behavior is akin to satellite formation in low-viscosity fluid streams subject to the Rayleigh-Plateau instability. The simulation results imply that the string segments will reach zero radius in finite asymptotic time, whence the classical space-time terminates in a naked singularity. Since no fine-tuning is required to excite the instability, this constitutes a generic violation of cosmic censorship.

  10. Electrical conductivity and viscosity of borosilicate glasses and melts

    DEFF Research Database (Denmark)

    Ehrt, Doris; Keding, Ralf

    2009-01-01

    , 0 to 62·5 mol% B2O3, and 25 to 85 mol% SiO2. The glass samples were characterised by different methods. Refractive indices, density and thermal expansion were measured. Phase separation effects were investigated by electron microscopy. The electrical conductivity of glasses and melts were determined...... by impedance measurements in a wide temperature range (250 to 1450°C). The activation energies were calculated by Arrhenius plots in various temperature regions: below the glass transition temperature, Tg, above the melting point, Tl, and between Tg and Tl. Viscosity measurements were carried out...... with different methods from Tg to the melt. The measured data were fitted and the activation energies calculated. Simple exponential behaviour was found only in very narrow temperature ranges. The effect of B2O3 in sodium borosilicate glasses and melts is discussed in comparison with sodium silicate glasses...

  11. Apsidal precession, disc breaking and viscosity in warped discs

    CERN Document Server

    Nealon, Rebecca; Price, Daniel J; King, Andrew

    2015-01-01

    We demonstrate the importance of general relativistic apsidal precession in warped black hole accretion discs by comparing three - dimensional smoothed particle hydrodynamic simulations in which this effect is first neglected, and then included. If apsidal precession is neglected, we confirm the results of an earlier magnetohydrodynamic simulation which made this assumption, showing that at least in this case the $\\alpha$ viscosity model produces very similar results to those of simulations where angular momentum transport is due to the magnetorotational instability. Including apsidal precession significantly changes the predicted disc evolution. For moderately inclined discs thick enough that tilt is transported by bending waves, we find a disc tilt which is nonzero at the inner disc edge and oscillates with radius, consistent with published analytic results. For larger inclinations we find disc breaking.

  12. Modulated Wave Packets in DNA and Impact of Viscosity

    Institute of Scientific and Technical Information of China (English)

    Conrad Bertrand Tabi; Alidou Mohamadou; Timoleon Crepin Kofan(e)

    2009-01-01

    We study the nonlinear dynamics of a DNA molecular system at physiological temperature in a viscous media by using the Peyrard-Bishop model.The nonlinear dynamics of the above system is shown to be governed by the discrete complex Ginzburg-Landau equation.In the non-viscous limit,the equation reduces to the nonlinear Schrodinger equation.Modulational instability criteria are derived for both the cases.On the basis of these criteria,numerical simulations are made,which confirm the analytical predictions.The planar wave solution used as the initial condition makes localized oscillations of base pairs and causes energy localization.The results also show that the viscosity of the solvent in the surrounding damps out the amplitude of wave patterns.

  13. Viscosity behavior of magnetic suspensions in fluid-assisted finishing

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Magnetic fluid-assisted finishing has been verified both theoretically and experimentally as an effective fabrication technology for optical mirrors and lenses. The purpose of this paper is to introduce a novel design of polishing tool and demonstrate the possible applications of this technology. The work includes studying the viscosity of the magnetic suspensions of micrometer-sized Carbonyl iron particles under the influence of a magnetic field. Both the cases of magnetizable suspension with and without abrasive cerium oxide particles are studied for their ensuing polishing effectiveness. Determination of material removal function is conducted using a Wyko Nat1100 interferometer. Experiments to reduce surface roughness with the proposed tool are also performed using a K9 mirror as the work-piece. Results show that the surface accuracy is improved over three times to less than 0.5 nm after two cycles of polishing.

  14. Viscosity Coefficients of a Nematic Mixture: Statistical Theory Approach

    Science.gov (United States)

    Terentjev, E. M.; Osipov, M. A.

    1991-09-01

    A statistical theory of the rotational diffusion of a molecule in a two-component anisotropic mixture is developed, based on the Fokker-Planck approximation for the one-particle orientational distribution function. The friction constant of the molecular rotation is determined from the threeparticle correlation function, which takes into account interactions A-A, A-B, B-A and B-B between two sorts of molecules. The Leslie coefficients obtained possess a complicated dependence on mixture concentration together with a dependence on temperature and the molecular parameters of the components. In particular, the rotational viscosity coefficient γj is proportional to a polynomial of third-order in concentrations cA and cB with coefficients proportional to exp{JAca + JBcB} √(JACA + JB bcB )

  15. Asymmetric tearing mode in the presence of viscosity

    Energy Technology Data Exchange (ETDEWEB)

    Militello, F. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Borgogno, D. [Dipartimento di Energetica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Grasso, D. [CNR Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, Dipartimento di Energetica, Politecnico di Torino, 10129 Torino (Italy); Marchetto, C. [Associazione EURATOM-ENEA sulla Fusione, IFP-CNR, Via R. Cozzi 53, 20125 Milano (Italy); Ottaviani, M. [Association EURATOM-CEA, CEA/DSM/IRFM, CEA Cadarache, 13108 St. Paul-lez-Durance (France)

    2011-11-15

    The linear stability of the tearing mode (TM) in a plasma column is investigated in the presence of viscosity and finite equilibrium current density gradients (i.e., asymmetries). It is shown that for low {beta}, both effects are essential in order to properly describe the mode behaviour close to marginality. In particular, the theory introduces a critical threshold for the destabilization, such that the perturbation grows only if {Delta}'>{Delta}'{sub cr}. The value of {Delta}'{sub cr} depends on the equilibrium configuration and on the plasma parameters. Most importantly, {Delta}'{sub cr} can take negative values, thus allowing unstable tearing modes for {Delta}' < 0 (even in the absence of bootstrap current).

  16. The Effect of Lubricant Viscosity in High Pressure Forming

    Science.gov (United States)

    Syahrullail, S.; Ridzuan, M. J. M.; Seah, W. B.

    2010-06-01

    In this research, the effects of viscosity of lubricant in cold work extrusion process were investigated. The experimental evaluation was carried out by using cold work plane strain extrusion apparatus with a pair of 45-degree die half angle and a symmetrical workpiece (billet). The billet material was annealed pure aluminum, A1100. The analytical evaluation was carried out using a visioplasticity method. The testing lubricant is RBD palm olein, RBD palm stearin and palm fatty acid distillate. The results were compared with the additive free paraffinic mineral oil. The result shows that palm oil has advantage in reducing the extrusion load. We confirmed that palm oil showed satisfactory lubrication performance, as compared to additive free paraffinic mineral oil.

  17. Mixing high-viscosity fluids via acoustically driven bubbles

    Science.gov (United States)

    Orbay, Sinem; Ozcelik, Adem; Lata, James; Kaynak, Murat; Wu, Mengxi; Huang, Tony Jun

    2017-01-01

    We present an acoustofluidic micromixer which can perform rapid and homogeneous mixing of highly viscous fluids in the presence of an acoustic field. In this device, two high-viscosity polyethylene glycol (PEG) solutions were co-injected into a three-inlet PDMS microchannel with the center inlet containing a constant stream of nitrogen flow which forms bubbles in the device. When these bubbles were excited by an acoustic field generated via a piezoelectric transducer, the two solutions mixed homogenously due to the combination of acoustic streaming, droplet ejection, and bubble eruption effects. The mixing efficiency of this acoustofluidic device was evaluated using PEG-700 solutions which are ~106 times more viscous than deionized (DI) water. Our results indicate homogenous mixing of the PEG-700 solutions with a ~0.93 mixing index. The acoustofluidic micromixer is compact, inexpensive, easy to operate, and has the capacity to mix highly viscous fluids within 50 ms.

  18. Phase and viscosity behaviour of refrigerant-lubricant mixtures

    DEFF Research Database (Denmark)

    Cisneros, Sergio; Garcia, J.; Fernandez, J.

    2005-01-01

    The understanding of thermophysical properties and phase behaviour of refrigerant-lubricant oil mixtures is highly important for the optimal design of refrigeration and air-conditioning systems. Refrigerant lubricant mixtures, which are likely to have strong asymmetry, can show complex phase...... behaviour such as closed miscibility gaps, open miscibility gaps, liquid-liquid-vapour equilibrium, and even barotropic phenomena (density inversions). In fact, the type of phase behaviour that refrigerant-lubricant mixtures may show is linked to the transition between different types of phase diagrams......, mainly as a function of the molecular asymmetry. This also has a profound effect in the mixture transport properties. Thus, in this work the general aspects of phase and viscosity behaviour linked to the type of asymmetry found in refrigerant-lubricant mixtures are discussed in the context of phase...

  19. Viscosity bound violation in holographic solids and the viscoelastic response

    Science.gov (United States)

    Alberte, Lasma; Baggioli, Matteo; Pujolàs, Oriol

    2016-07-01

    We argue that the Kovtun-Son-Starinets (KSS) lower bound on the viscosity to entropy density ratio holds in fluid systems but is violated in solid materials with a nonzero shear elastic modulus. We construct explicit examples of this by applying the standard gauge/gravity duality methods to massive gravity and show that the KSS bound is clearly violated in black brane solutions whenever the massive gravity theories are of solid type. We argue that the physical reason for the bound violation relies on the viscoelastic nature of the mechanical response in these materials. We speculate on whether any real-world materials can violate the bound and discuss a possible generalization of the bound that involves the ratio of the shear elastic modulus to the pressure.

  20. Viscosity bound violation in holographic solids and the viscoelastic response

    CERN Document Server

    Alberte, Lasma; Pujolas, Oriol

    2016-01-01

    We argue that the Kovtun--Son--Starinets (KSS) lower bound on the viscosity to entropy density ratio holds in fluid systems but is violated in solid materials with a non-zero shear elastic modulus. We construct explicit examples of this by applying the standard gauge/gravity duality methods to massive gravity and show that the KSS bound is clearly violated in black brane solutions whenever the massive gravity theories are of solid type. We argue that the physical reason for the bound violation relies on the viscoelastic nature of the mechanical response in these materials. We speculate on whether any real-world materials can violate the bound and discuss a possible generalization of the bound that involves the ratio of the shear elastic modulus to the pressure.