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Sample records for volume bolus viscosity

  1. Effect of bolus volume and viscosity on pharyngeal automated impedance manometry variables derived for broad Dysphagia patients.

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    Omari, Taher I; Dejaeger, Eddy; Tack, Jan; Van Beckevoort, Dirk; Rommel, Nathalie

    2013-06-01

    Automated impedance manometry (AIM) analysis measures swallow variables defining bolus timing, pressure, contractile vigour, and bolus presence, which are combined to derive a swallow risk index (SRI) correlating with aspiration. In a heterogeneous cohort of dysphagia patients, we assessed the impact of bolus volume and viscosity on AIM variables. We studied 40 patients (average age = 46 years). Swallowing of boluses was recorded with manometry, impedance, and videofluoroscopy. AIMplot software was used to derive functional variables: peak pressure (PeakP), pressure at nadir impedance (PNadImp), time from nadir impedance to peak pressure (TNadImp-PeakP), the interval of impedance drop in the distal pharynx (flow interval, FI), upper oesophageal sphincter (UES) relaxation interval (UES RI), nadir UES pressure (Nad UESP), UES intrabolus pressure (UES IBP), and UES resistance. The SRI was derived using the formula SRI = (FI * PNadImp)/(PeakP * (TNadImp-PeakP + 1)) * 100. A total of 173 liquid, 44 semisolid, and 33 solid boluses were analysed. The SRI was elevated in relation to aspiration. PeakP increased with volume. SRI was not significantly altered by bolus volume. PNadImp, UES IBP, and UES resistance increased with viscosity. SRI was lower with increased viscosity. In patients with dysphagia, the SRI is elevated in relation to aspiration, reduced by bolus viscosity, and not affected by bolus volume. These data provide evidence that pharyngeal AIM analysis may have clinical utility for assessing deglutitive aspiration risk to liquid boluses.

  2. Effects of Age, Gender, Bolus Volume, Bolus Viscosity, and Gustation on Swallowing Apnea Onset Relative to Lingual Bolus Propulsion Onset in Normal Adults

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    Hiss, Susan G.; Strauss, Monica; Treole, Kathleen; Stuart, Andrew; Boutilier, Susan

    2004-01-01

    The purpose of this study was to ascertain the normal relation of swallowing apnea (SA) onset relative to lingual bolus propulsion along with factors that may alter this relation. Forty adults, composed of 10 men and 10 women in each of 2 age groups (i.e., 20-30 and 63-79 years) participated. SA onset was assessed during 5- and 20-ml bolus volumes…

  3. Viscosity of food boluses affects the axial force in the esophagus

    Institute of Scientific and Technical Information of China (English)

    Flemming Gravesen; Niall Behan; Asbjorn Drewes; Hans Gregersen

    2011-01-01

    AIM: To study the effect of viscosity on axial force in the esophagus during primary peristalsis using a newly vali-dated impedance-based axial force recording technique. METHODS: A probe able to simultaneously measure both axial force and manometry was positioned above the lower esophageal sphincter. Potable tap water and three thickened fluids were used to create boluses of different viscosities. Water has a viscosity of 1 mPa·s. The three thickened fluids were made with different concentrations of Clinutren Instant thickener. The vis-cous fluids were in appearance comparable to pudding (2 kPa·s), yogurt (6 kPa·s) and slush ice (10 kPa·s). Six healthy volunteers swallowed 5 and 10 mL of bo-luses multiple times. RESULTS: The pressure amplitude did not increase with the bolus viscosity nor with the bolus volume whereas the axial force increased marginally with bo-lus volume (0.1 > P > 0.05). Both techniques showed that contraction duration increased with bolus viscosity (P < 0.01). Association was found between axial force and pressure but the association became weaker with increasing viscosity. The pressure amplitude did not in-crease with the viscosity or bolus volume whereas the axial force increased marginally with the bolus size. CONCLUSION: This indicates a discrepancy between the physiological functions that can be recorded with axial force measurements and pressure measurements.

  4. A mathematical model for the movement of food bolus of varying viscosities through the esophagus

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    Tripathi, Dharmendra

    2011-09-01

    This mathematical model is designed to study the influence of viscosity on swallowing of food bolus through the esophagus. Food bolus is considered as viscous fluid with variable viscosity. Geometry of esophagus is assumed as finite length channel and flow is induced by peristaltic wave along the length of channel walls. The expressions for axial velocity, transverse velocity, pressure gradient, volume flow rate and stream function are obtained under the assumptions of long wavelength and low Reynolds number. The impacts of viscosity parameter on pressure distribution, local wall shear stress, mechanical efficiency and trapping are numerically discussed with the help of computational results. On the basis of presented study, it is revealed that swallowing of low viscous fluids through esophagus requires less effort in comparison to fluids of higher viscosity. This result is similar to the experimental result obtained by Raut et al. [1], Dodds [2] and Ren et al. [3]. It is further concluded that the pumping efficiency increases while size of trapped bolus reduces when viscosity of fluid is high.

  5. The effect of bolus viscosity on swallowing function in neurogenic dysphagia.

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    Clavé, P; de Kraa, M; Arreola, V; Girvent, M; Farré, R; Palomera, E; Serra-Prat, M

    2006-11-01

    To assess the pathophysiology and treatment of neurogenic dysphagia. 46 patients with brain damage, 46 with neurodegenerative diseases and eight healthy volunteers were studied by videofluoroscopy while swallowing 3-20 mL liquid (20.4 mPa s), nectar (274.4 mPa s) and pudding (3931.2 mPa s) boluses. Volunteers presented a safe and efficacious swallow, short swallow response ( or =0.33 mJ). Brain damage patients presented: (i) 21.6% aspiration of liquids, reduced by nectar (10.5%) and pudding (5.3%) viscosity (P or =806 ms) with a delay in laryngeal closure (> or =245 ms), and weak bolus propulsion forces (neurogenic dysphagia presented high prevalence of videofluoroscopic signs of impaired safety and efficacy of swallow, and were at high risk of respiratory and nutritional complications. Impaired safety is associated with slow oropharyngeal reconfiguration and impaired efficacy with low bolus propulsion. Increasing bolus viscosity greatly improves swallowing function in neurological patients.

  6. A biomechanical model of swallowing for understanding the influence of saliva and food bolus viscosity on flavour release

    CERN Document Server

    De Loubens, Clément; Doyennette, Marion; Tréléa, Ioan Cristian; Souchon, Isabelle

    2013-01-01

    After swallowing a liquid or a semi-liquid food product, a thin film responsible for the dynamic profile of aroma release coats the pharyngeal mucosa. The objective of the present article was to understand and quantify physical mechanisms explaining pharyngeal mucosa coating. An elastohydrodynamic model of swallowing was developed for Newtonian liquids that focused on the most occluded region of the pharyngeal peristaltic wave. The model took lubrication by a saliva film and mucosa deformability into account. Food bolus flow rate and generated load were predicted as functions of three dimensionless variables: the dimensionless saliva flow rate, the viscosity ratio between saliva and the food bolus, and the elasticity number. Considering physiological conditions, the results were applied to predict aroma release kinetics. Two sets of conditions were distinguished. The first one was obtained when the saliva film is thin, in which case food bolus viscosity has a strong impact on mucosa coating and on flavour rel...

  7. Impact of bolus volume on small intestinal intra-luminal impedance in healthy subjects

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    Nam; Q; Nguyen; Laura; K; Bryant; Carly; M; Burgstad; Robert; J; Fraser; Daniel; Sifrim; Richard; H; Holloway

    2010-01-01

    AIM: To assess the impact of bolus volume on the characteristics of small intestinal (SI) impedance signals.METHODS: Concurrent SI manometry-impedance measurements were performed on 12 healthy volunteers to assess the pattern of proximal jejunal fluid bolus movement over a 14 cm-segment.Each subject was given 34 boluses of normal saline (volume from 1 to 30 mL) via the feeding tube placed immediately above the proximal margin of the studied segment.A bolus-induced impedance event occurred if there was > 12%...

  8. Lung Volume during Swallowing: Single Bolus Swallows in Healthy Young Adults

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    Hegland, Karen M. Wheeler; Huber, Jessica E.; Pitts, Teresa; Sapienza, Christine M.

    2009-01-01

    Purpose: This study examined the relationship between swallowing and lung volume initiation in healthy adults during single swallows of boluses differing in volume and consistency. Differences in lung volume according to respiratory phase surrounding the swallow were also assessed. Method: Nine men and 11 women between the ages of 19 and 28 years…

  9. Lung Volume during Swallowing: Single Bolus Swallows in Healthy Young Adults

    Science.gov (United States)

    Hegland, Karen M. Wheeler; Huber, Jessica E.; Pitts, Teresa; Sapienza, Christine M.

    2009-01-01

    Purpose: This study examined the relationship between swallowing and lung volume initiation in healthy adults during single swallows of boluses differing in volume and consistency. Differences in lung volume according to respiratory phase surrounding the swallow were also assessed. Method: Nine men and 11 women between the ages of 19 and 28 years…

  10. Combined left and right ventricular volume determination by radionuclide angiocardiography using double bolus and equilibrium technique

    DEFF Research Database (Denmark)

    Stokholm, K H; Stubgaard, M; Møgelvang, J;

    1990-01-01

    by indicator dilution. The radionuclide technique comprised four steps: (1) a first-pass study of right ventricle; (2) a bolus study of left ventricle; (3) an equilibrium study of left ventricle; (4) determination of the distribution volume of red blood cells. Absolute volumes of left ventricle were determined......Eighteen patients with ischaemic heart disease were studied. Left and right ventricular volumes including cardiac output (forward flow) were determined by radionuclide angiocardiography using a double bolus and equilibrium technique. As reference, cardiac output was simultaneously measured...... from steps 2 + 3 + 4. Absolute volumes of right ventricle were calculated from stroke volume and right ventricular ejection fraction (EF) which in turn was determined from step 1 by creating composite systolic and composite diastolic images. There was an acceptable agreement between stroke volume...

  11. The Effect of Bolus Volume on Hyoid Kinematics in Healthy Swallowing

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    Ahmed Nagy

    2014-01-01

    Full Text Available Hyoid movement in swallowing is biomechanically linked to closure of the laryngeal vestibule for airway protection and to opening of the upper esophageal sphincter. Studies suggest that the range of hyoid movement is highly variable in the healthy population. However, other aspects of hyoid movement such as velocity remain relatively unexplored. In this study, we analyze data from a sample of 20 healthy young participants (10 male to determine whether hyoid movement distance, duration, velocity, and peak velocity vary systematically with increases in thin liquid bolus volume from 5 to 20 mL. The temporal correspondence between peak hyoid velocity and laryngeal vestibule closure was also examined. The results show that maximum hyoid position and peak velocity increase significantly for 20 mL bolus volumes compared to smaller volumes, and that the timing of peak velocity is closely linked to achieving laryngeal vestibule closure. This suggests that generating hyoid movements with increased power is a strategy for handling larger volumes.

  12. Fabrication of Artificial Food Bolus for Evaluation of Swallowing

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    Hosotsubo, Miyu; Magota, Tetsuro; Egusa, Masahiko; Miyawaki, Takuya; Matsumoto, Takuya

    2016-01-01

    Simple and easy methods to evaluate swallowing are required because of the recently increased need of rehabilitation for dysphagia. "Artificial food bolus", but not "artificial food", would be a valuable tool for swallowing evaluation without considering the mastication effect which is altered according to the individual's oral condition. Thus, this study was carried out to fabricate artificial bolus resembling natural food bolus. The mechanical property and the volume change of food bolus in normal people were firstly investigated. Thirty healthy adults without dysphagia were selected and asked to chew four sample foods (rice cake, peanut, burdock, and gummy candy). The results indicated that Young’s modulus of bolus before swallowing was below 150 kPa. The bolus volume before swallowing was below 400 mm3. In addition, the saliva component ratio of each bolus was approximately 30wt%, and the average saliva viscosity of research participants was approximately 10 mPa•s. Based on the obtained data, artificial food bolus was designed and fabricated by using alginate hydrogel as a visco-elastic material and gelatin solution as a viscotic material with a ratio of 7:3 based on weight. Consequently, the swallowing time of fabricated artificial food bolus was measured among the same participants. The results indicated the participants swallowed fabricated food bolus with similar manner reflecting their mechanical property and volume. Thus, this artificial food bolus would be a promising tool for evaluation of swallowing. PMID:27977775

  13. Reduction of contrast medium volume in abdominal aorta CTA: Multiphasic injection technique versus a test bolus volume

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    Nijhof, Wouter H., E-mail: w.h.nijhof@student.utwente.nl [University of Twente, MIRA-Institute for Biomedical Technology and Technical Medicine, P.O. Box 21, 7500 AE Enschede (Netherlands); Vos, Charlotte S. van der, E-mail: c.s.vandervos@student.utwente.nl [University of Twente, MIRA-Institute for Biomedical Technology and Technical Medicine, P.O. Box 21, 7500 AE Enschede (Netherlands); Anninga, Bauke, E-mail: b.anninga@student.utwente.nl [University of Twente, MIRA-Institute for Biomedical Technology and Technical Medicine, P.O. Box 21, 7500 AE Enschede (Netherlands); Jager, Gerrit J., E-mail: g.jager@JBZ.nl [Department of Radiology, Jeroen Bosch Hospital, Henri Dunantstraat 1, 5223 GZ ’s-Hertogenbosch (Netherlands); Rutten, Matthieu J.C.M., E-mail: mj.rutten@online.nl [Department of Radiology, Jeroen Bosch Hospital, Henri Dunantstraat 1, 5223 GZ ’s-Hertogenbosch (Netherlands)

    2013-09-15

    Objective: The purpose of this study is to reduce the administered contrast medium volume in abdominal CTA by using a test bolus injection, with the preservation of adequate quantitative and qualitative vessel enhancement. Study design: For this technical efficacy study 30 patients, who were referred for a CTA examination of the abdominal aorta, were included. Randomly 15 patients were assigned to undergo a multiphasic injection protocol and received 89 mL of contrast medium (Optiray 350) (protocol I). Fifteen patients were assigned to the test bolus injection protocol (protocol II), which implies injection of a 10 mL test bolus of Optiray 350 prior to performing CTA with a 40 mL of contrast medium. Quantitative assessment of vascular enhancement was performed by measuring the amount of Hounsfield Units in the aorta at 30 positions from the celiac trunk to the iliac arteries in both groups. Qualitative assessment was performed by three radiologists who scored the images at a 5-point scale. Results: Quantitative assessment showed that there was no significant difference in vascular enhancement for patients between the two protocols, with mean attenuation values of 280.9 ± 50.84 HU and 258.60 ± 39.28 HU, respectively. The image quality of protocol I was rated 4.31 (range: 3.67/5.00) and of protocol II 4.11 (range: 2.67/5.00). These differences were not statistically significant. Conclusion: This study showed that by using a test bolus injection and the administration of 50 mL of contrast medium overall, CTA of the abdominal aorta can reliably be performed, with regard to quantitative and qualitative adequate vessel enhancement.

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

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    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.

  15. In vitro evaluation of the impact of ultrasound scanner settings and contrast bolus volume on time-intensity curves.

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    Gauthier, Thomas P; Chebil, Mohamed; Peronneau, Pierre; Lassau, Nathalie

    2012-01-01

    The objective of this study was to assess in vitro the impact of ultrasound scanner settings and contrast bolus volume on time-intensity curves formed from dynamic contrast-enhanced ultrasound image loops. An indicator-dilution experiment was developed with an in vitro flow phantom setup used with SonoVue contrast agent (Bracco SpA, Milan, Italy). Imaging was performed with a Philips iU22 scanner and two transducers (L9-3 linear and C5-1 curvilinear). The following ultrasound scanner settings were investigated, along with contrast bolus volume: contrast-specific nonlinear pulse sequence, gain, mechanical index, focal zone depth, acoustic pulse center frequency and bandwidth. Four parameters (rise time, mean transit time, peak intensity, and area under the curve) were derived from time-intensity curves which were obtained after pixel by pixel linearization of log-compressed data (also referred to as video data) included in a region of interest. Rise time was found to be the parameter least impacted by changes to ultrasound scanner settings and contrast bolus volume; the associated coefficient of variation varied between 0.7% and 6.9% while it varied between 0.8% and 19%, 12% and 71%, and 9.2% and 66%, for mean transit time, peak intensity, and area under the curve, respectively. The present study assessed the impact of ultrasound scanner settings and contrast bolus volume on time-intensity curve analysis. One should be aware of these issues to standardize their technique in each specific organ of interest and to achieve accurate, sensitive, and reproducible data using dynamic contrast-enhanced ultrasound. One way to mitigate the impact of ultrasound scanner settings in longitudinal, multi-center quantitative dynamic contrast-enhanced ultrasound studies may be to prohibit any adjustments to those settings throughout a given study. Further clinical studies are warranted to confirm the reproducibility and diagnostic or prognostic value of time-intensity curve

  16. Excess Molar Volumes and Viscosities of Binary Mixture of Diethyl Carbonate+Ethanol at Different Temperatures

    Institute of Scientific and Technical Information of China (English)

    MA Peisheng; LI Nannan

    2005-01-01

    The purpose of this work was to report excess molar volumes and dynamic viscosities of the binary mixture of diethyl carbonate (DEC)+ethanol. Densities and viscosities of the binary mixture of DEC+ethanol at temperatures 293.15 K-343.15 K and atmospheric pressure were determined over the entire composition range. Densities of the binary mixture of DEC+ethanol were measured by using a vibrating U-shaped sample tube densimeter. Viscosities were determined by using Ubbelohde suspended-level viscometer. Densities are accurate to 1.0×10-5 g·cm-3, and viscosities are reproducible within ±0.003 mPa·s. From these data, excess molar volumes and deviations in viscosity were calculated. Positive excess molar volumes and negative deviations in viscosity for DEC+ethanol system are due to the strong specific interactions.All excess molar vo-lumes and deviations in viscosity fit to the Redlich-Kister polynomial equation.The fitting parameters were presented,and the average deviations and standard deviations were also calculated.The errors of correlation are very small.It proves that it is valuable for estimating densities and viscosities of the binary mixture by the correlated equation.

  17. Effects of activation energy and activation volume on the temperature-dependent viscosity of water

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    Kwang-Hua, Chu Rainer

    2016-08-01

    Water transport in a leaf is vulnerable to viscosity-induced changes. Recent research has suggested that these changes may be partially due to variation at the molecular scale, e.g., regulations via aquaporins, that induce reductions in leaf hydraulic conductance. What are the quantitative as well as qualitative changes in temperature-dependent viscosity due to the role of aquaporins in tuning activation energy and activation volume? Using the transition-state approach as well as the boundary perturbation method, we investigate temperature-dependent viscosity tuned by activation energy and activation volume. To validate our approach, we compare our numerical results with previous temperature-dependent viscosity measurements. The rather good fit between our calculations and measurements confirms our present approach. We have obtained critical parameters for the temperature-dependent (shear) viscosity of water that might be relevant to the increasing and reducing of leaf hydraulic conductance. These parameters are sensitive to temperature, activation energy, and activation volume. Once the activation energy increases, the (shear) viscosity of water increases. Our results also show that as the activation volume increases (say, 10-23m3 ), the (shear) viscosity of water decreases significantly and the latter induces the enhancing of leaf hydraulic conductance. Within the room-temperature regime, a small increase in the activation energy will increase the water viscosity or reduce the leaf hydraulic conductance. Our approach and results can be applied to diverse plant or leaf attributes.

  18. Absolute cerebral blood flow and blood volume measured by magnetic resonance imaging bolus tracking: comparison with positron emission tomography values

    DEFF Research Database (Denmark)

    Østergaard, Leif; Smith, D F; Vestergaard-Poulsen, Peter;

    1998-01-01

    The authors determined cerebral blood flow (CBF) with magnetic resonance imaging (MRI) of contrast agent bolus passage and compared the results with those obtained by O-15 labeled water (H215O) and positron emission tomography (PET). Six pigs were examined by MRI and PET under normo......- and hypercapnic conditions. After dose normalization and introduction of an empirical constant phi Gd, absolute regional CBF was calculated from MRI. The spatial resolution and the signal-to-noise ratio of CBF measurements by MRI were better than by the H215O-PET protocol. Magnetic resonance imaging cerebral...... blood volume (CBV) estimates obtained using this normalization constant correlated well with values obtained by O-15 labeled carbonmonooxide (C15O) PET. However, PET CBV values were approximately 2.5 times larger than absolute MRI CBV values, supporting the hypothesized sensitivity of MRI to small...

  19. The rheology of hard sphere suspensions at arbitrary volume fractions: An improved differential viscosity model.

    Science.gov (United States)

    Mendoza, Carlos I; Santamaría-Holek, I

    2009-01-28

    We propose a simple and general model accounting for the dependence of the viscosity of a hard sphere suspension at arbitrary volume fractions. The model constitutes a continuum-medium description based on a recursive-differential method where correlations between the spheres are introduced through an effective volume fraction. In contrast to other differential methods, the introduction of the effective volume fraction as the integration variable implicitly considers interactions between the spheres of the same recursive stage. The final expression for the viscosity scales with this effective volume fraction, which allows constructing a master curve that contains all the experimental situations considered. The agreement of our expression for the viscosity with experiments at low- and high-shear rates and in the high-frequency limit is remarkable for all volume fractions.

  20. Measurement of fluid viscosity at microliter volumes using quartz impedance analysis.

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    Saluja, Atul; Kalonia, Devendra S

    2004-08-05

    The purpose of this work was to measure viscosity of fluids at low microliter volumes by means of quartz crystal impedance analysis. To achieve this, a novel setup was designed that allowed for measurement of viscosity at volumes of 8 to 10 microL. The technique was based on the principle of electromechanical coupling of piezoelectric quartz crystals. The arrangement was simple with measurement times ranging from 2 to 3 minutes. The crystal setup assembly did not impose any unwanted initial stress on the unloaded quartz crystal. Quartz crystals of 5- and 10-MHz fundamental frequency were calibrated with glycerol-water mixtures of known density and viscosity prior to viscosity measurements. True frequency shifts, for the purpose of this work, were determined followed by viscosity measurement of aqueous solutions of sucrose, urea, PEG-400, glucose, and ethylene glycol at 25 degrees C +/- 0.5 degrees C. The measured viscosities were found to be reproducible and consistent with the values reported in the literature. Minor inconsistencies in the measured resistance and frequency shifts did not affect the results significantly, and were found to be experimental in origin rather than due to electrode surface roughness. Besides, as expected for a viscoelastic fluid, PEG 8000 solutions, the calculated viscosities were found to be less than the reported values due to frequency dependence of storage and loss modulus components of complex viscosity. From the results, it can be concluded that the present setup can provide accurate assessment of viscosity of Newtonian fluids and also shows potential for analyzing non-Newtonian fluids at low microliter volumes.

  1. Viscosity of water-in-oil emulsions. Variation with temperature and water volume fraction

    Energy Technology Data Exchange (ETDEWEB)

    Farah, Marco A.; Caldas, Jorge Navaes [Petroleo Brasileiro S.A., Rua General Canabarro, 500, Maracana, Rio, CEP 2057-900 (Brazil); Oliveira, Roberto C. [Petroleo Brasileiro S.A., Cenpes, Cidade Universitaria (Brazil); Rajagopal, Krishnaswamy [LATCA-Laboratorio de Termodinamica e Cinetica Aplicada-Escola de Quimica, Departamento de Engenharia Quimica, Universidade Federal do Rio de Janeiro, UFRJ, Cidade Universitaria, C.P. 68452, CEP 21949-900, Rio de Janeiro (Brazil)

    2005-09-15

    Water-in-oil emulsions are important in the petroleum industry in production operations, where the water content of the emulsion can be as high as 60% in volume, also in petroleum refining operations where generally the water content is low. The effective viscosity of water-in-oil emulsions depends mainly on the volume fraction of dispersed phase and temperature, along with several minor effects, such as shear rate, average droplet size, droplet size distribution, viscosity and density of oil. Using six different crude oils, the effective viscosities of several synthetic water-in-oil emulsions are measured at atmospheric pressure using a dynamic viscosimeter for different shear rates, temperatures and volume fractions of the dispersed phase. The ASTM equation, method D-341, for describing viscosity as a function of temperature is extended to include the variation of dispersed phase volume fraction. The proposed equation gives good correlation between the measured viscosities of water-in-oil emulsions as a function of temperature and the volume fraction of water.

  2. AN EMPIRICAL FORMULA FOR THE RELATION BETWEEN VISCOSITY OF SOLUTION AND VOLUME OF SOLUTE.

    Science.gov (United States)

    Kunitz, M

    1926-07-20

    It has been found that the expression See PDF for Equation represents very closely the relation between the volume of the solute and the viscosity of the solution. The formula has been applied to a number of experimental results and found to hold very well for as high concentrations as 50 per cent solutions of such substances as sugars, glycogen, casein, and rubber. In the case of various sugar solutions, and also in the case of sulfur suspensions, the volume of the solute as calculated from the viscosity values agrees with the actual volume of the substance in dry state, as determined from specific gravity measurement, while in the case of caoutchouc solutions in benzene the values of varphi as calculated from the viscosity measurements fit remarkably well in the equation for osmotic pressure.

  3. Viscosity and volume properties of the Al-Cu melts

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    Kurochkin A.

    2011-05-01

    Full Text Available Temperature dependences of the kinematic viscosity v and the density ρ of Al-Cu melts were investigated in the same regime taking into account that viscometric experiments with the melts enriched with cupper have not been repeated since 1960th and densimetric measurements did not perform before at all. The first measurements were fulfilled using the method of dumping oscillation of a crucible filled in by a melt investigated. Its precision was as high as 1.5%. Density was measured using the gamma-absorption method with the accuracy of 0.2 to 0.3%. Crucibles of BeO were used in both the cases. In the course of the measurements a distinct branching of the heating and cooling curves were fixed below some temperature characteristic of each composition for most of the investigated samples. The branching temperature systematically changes with growth of cupper content. The authors believe that the effect is caused by the irreversible transition of the melts from microheterogeneous state inherited from the initial rough materials into a true solution state.

  4. 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.

  5. Continuous versus bolus tube feeds: Does the modality affect glycemic variability, tube feeding volume, caloric intake, or insulin utilization?

    Science.gov (United States)

    Evans, David C; Forbes, Rachel; Jones, Christian; Cotterman, Robert; Njoku, Chinedu; Thongrong, Cattleya; Tulman, David; Bergese, Sergio D; Thomas, Sheela; Papadimos, Thomas J; Stawicki, Stanislaw P

    2016-01-01

    Introduction: Enteral nutrition (EN) is very important to optimizing outcomes in critical illness. Debate exists regarding the best strategy for enteral tube feeding (TF), with concerns that bolus TF (BTF) may increase glycemic variability (GV) but result in fewer nutritional interruptions than continuous TF (CTF). This study examines if there is a difference in GV, insulin usage, TF volume, and caloric delivery among intensive care patients receiving BTF versus CTF. We hypothesize that there are no significant differences between CTF and BTF when comparing the above parameters. Materials and Methods: Prospective, randomized pilot study of critically ill adult patients undergoing percutaneous endoscopic gastrostomy (PEG) placement for EN was performed between March 1, 2012 and May 15, 2014. Patients were randomized to BTF or CTF. Glucose values, insulin use, TF volume, and calories administered were recorded. Data were organized into 12-h epochs for statistical analyses and GV determination. In addition, time to ≥80% nutritional delivery goal, demographics, Acute Physiology and Chronic Health Evaluation II scores, and TF interruptions were examined. When performing BTF versus CTF assessments, continuous parameters were compared using Mann–Whitney U-test or repeated measures t-test, as appropriate. Categorical data were analyzed using Fisher's exact test. Results: No significant demographic or physiologic differences between the CTF (n = 24) and BTF (n = 26) groups were seen. The immediate post-PEG 12-h epoch showed significantly lower GV and median TF volume for patients in the CTF group. All subsequent epochs (up to 18 days post-PEG) showed no differences in GV, insulin use, TF volume, or caloric intake. Insulin use for both groups increased when comparing the first 24 h post-PEG values to measurements from day 8. There were no differences in TF interruptions, time to ≥80% nutritional delivery goal, or hypoglycemic episodes. Conclusions: This study

  6. Technical Note: New methodology for measuring viscosities in small volumes characteristic of environmental chamber particle samples

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    L. Renbaum-Wolff

    2012-10-01

    Full Text Available Herein, a method for the determination of viscosities of small sample volumes is introduced, with important implications for the viscosity determination of particle samples from environmental chambers (used to simulate atmospheric conditions. The amount of sample needed is < 1 μl, and the technique is capable of determining viscosities (η ranging between 10−3 and 103 Pascal seconds (Pa s in samples that cover a range of chemical properties and with real-time relative humidity and temperature control; hence, the technique should be well-suited for determining the viscosities, under atmospherically relevant conditions, of particles collected from environmental chambers. In this technique, supermicron particles are first deposited on an inert hydrophobic substrate. Then, insoluble beads (~1 μm in diameter are embedded in the particles. Next, a flow of gas is introduced over the particles, which generates a shear stress on the particle surfaces. The sample responds to this shear stress by generating internal circulations, which are quantified with an optical microscope by monitoring the movement of the beads. The rate of internal circulation is shown to be a function of particle viscosity but independent of the particle material for a wide range of organic and organic-water samples. A calibration curve is constructed from the experimental data that relates the rate of internal circulation to particle viscosity, and this calibration curve is successfully used to predict viscosities in multicomponent organic mixtures.

  7. Evaluation of the impact of viscosity, injection volume, and injection flow rate on subcutaneous injection tolerance

    Directory of Open Access Journals (Sweden)

    Berteau C

    2015-11-01

    Full Text Available Cecile Berteau,1 Orchidée Filipe-Santos,1 Tao Wang,2 Humberto E Rojas,2 Corinne Granger,1 Florence Schwarzenbach1 1Becton-Dickinson Medical Pharmaceutical Systems, Le Pont de Claix, France; 2Eli Lilly and Company, Indianapolis, IN, USA Aim: The primary objective of this study was to evaluate the impact of fluid injection viscosity in combination with different injection volumes and flow rates on subcutaneous (SC injection pain tolerance. Methods: The study was a single-center, comparative, randomized, crossover, Phase I study in 24 healthy adults. Each participant received six injections in the abdomen area of either a 2 or 3 mL placebo solution, with three different fluid viscosities (1, 8–10, and 15–20 cP combined with two different injection flow rates (0.02 and 0.3 mL/s. All injections were performed with 50 mL syringes and 27G, 6 mm needles. Perceived injection pain was assessed using a 100 mm visual analog scale (VAS (0 mm/no pain, 100 mm/extreme pain. The location and depth of the injected fluid was assessed through 2D ultrasound echography images. Results: Viscosity levels had significant impact on perceived injection pain (P=0.0003. Specifically, less pain was associated with high viscosity (VAS =12.6 mm than medium (VAS =16.6 mm or low (VAS =22.1 mm viscosities, with a significant difference between high and low viscosities (P=0.0002. Target injection volume of 2 or 3 mL was demonstrated to have no significant impact on perceived injection pain (P=0.89. Slow (0.02 mL/s or fast (0.30 mL/s injection rates also showed no significant impact on perceived pain during SC injection (P=0.79. In 92% of injections, the injected fluid was located exclusively in SC tissue whereas the remaining injected fluids were found located in SC and/or intradermal layers. Conclusion: The results of this study suggest that solutions of up to 3 mL and up to 15–20 cP injected into the abdomen within 10 seconds are well tolerated without pain. High

  8. Ultrasonic methods for measuring liquid viscosity and volume percent of solids

    Energy Technology Data Exchange (ETDEWEB)

    Sheen, S.H.; Chien, H.T.; Raptis, A.C.

    1997-02-01

    This report describes two ultrasonic techniques under development at Argonne National Laboratory (ANL) in support of the tank-waste transport effort undertaken by the U.S. Department of Energy in treating low-level nuclear waste. The techniques are intended to provide continuous on-line measurements of waste viscosity and volume percent of solids in a waste transport line. The ultrasonic technique being developed for waste-viscosity measurement is based on the patented ANL viscometer. Focus of the viscometer development in this project is on improving measurement accuracy, stability, and range, particularly in the low-viscosity range (<30 cP). A prototype instrument has been designed and tested in the laboratory. Better than 1% accuracy in liquid density measurement can be obtained by using either a polyetherimide or polystyrene wedge. To measure low viscosities, a thin-wedge design has been developed and shows good sensitivity down to 5 cP. The technique for measuring volume percent of solids is based on ultrasonic wave scattering and phase velocity variation. This report covers a survey of multiple scattering theories and other phenomenological approaches. A theoretical model leading to development of an ultrasonic instrument for measuring volume percent of solids is proposed, and preliminary measurement data are presented.

  9. Evaluation of the impact of viscosity, injection volume, and injection flow rate on subcutaneous injection tolerance.

    Science.gov (United States)

    Berteau, Cecile; Filipe-Santos, Orchidée; Wang, Tao; Rojas, Humberto E; Granger, Corinne; Schwarzenbach, Florence

    2015-01-01

    The primary objective of this study was to evaluate the impact of fluid injection viscosity in combination with different injection volumes and flow rates on subcutaneous (SC) injection pain tolerance. The study was a single-center, comparative, randomized, crossover, Phase I study in 24 healthy adults. Each participant received six injections in the abdomen area of either a 2 or 3 mL placebo solution, with three different fluid viscosities (1, 8-10, and 15-20 cP) combined with two different injection flow rates (0.02 and 0.3 mL/s). All injections were performed with 50 mL syringes and 27G, 6 mm needles. Perceived injection pain was assessed using a 100 mm visual analog scale (VAS) (0 mm/no pain, 100 mm/extreme pain). The location and depth of the injected fluid was assessed through 2D ultrasound echography images. Viscosity levels had significant impact on perceived injection pain (P=0.0003). Specifically, less pain was associated with high viscosity (VAS =12.6 mm) than medium (VAS =16.6 mm) or low (VAS =22.1 mm) viscosities, with a significant difference between high and low viscosities (P=0.0002). Target injection volume of 2 or 3 mL was demonstrated to have no significant impact on perceived injection pain (P=0.89). Slow (0.02 mL/s) or fast (0.30 mL/s) injection rates also showed no significant impact on perceived pain during SC injection (P=0.79). In 92% of injections, the injected fluid was located exclusively in SC tissue whereas the remaining injected fluids were found located in SC and/or intradermal layers. The results of this study suggest that solutions of up to 3 mL and up to 15-20 cP injected into the abdomen within 10 seconds are well tolerated without pain. High viscosity injections were shown to be the most tolerated, whereas injection volume and flow rates did not impact perceived pain.

  10. Comparison the effect of two ways of tube feeding including bolus and continuous infusion on gastric residual volume and diarrhea in patients hospitalized in Intensive Care Unit

    Directory of Open Access Journals (Sweden)

    Shahriari M

    2015-05-01

    Full Text Available Background and Objective: Proper nutritional support is one of the important caring aspects in patients who were hospitalized in Intensive Care Unit. Although the several studies have been done concerning the selection of proper nutrition method for patients, but there is no agreement on this issue. The aim of current study was the compare the effect of two ways of tube feeding including bolus and continuous infusion on gastric residual volume and diarrhea in patients hospitalized in Intensive Care Unit.  Materials and Method: The current clinical trial was conducted on patients who were hospitalized in intensive care unit in Alzahra hospital in Isfahan, 2013. Fifty patients were selected through convenient sampling and were randomly assigned into two groups of 25 people of intervention and control. Nutrition was done through infusion pump in intervention group and by bolus in control group. Gastric residual volume and diarrhea was assessed each four hours for four days. Data were gathered through checklist and were analyzed by SPSS18 using descriptive and inferential statistics including independent T-test, Fisher's exact test and repeated measures ANOVA.  Results: The results showed that the mean of gastric residual volume in control group was more than the intervention group on the third day (p=0.04. Also, the mean of gastric residual volume did not show significant difference at different times in intervention group, but the mean of gastric residual volume was significantly increased in control group at different times (p=0.04. Fisher's exact test showed no significant difference between two groups concerning the diarrhea frequency.  Conclusion: In nutritional support with continuous infusion method, gastric residual volume was not increased and gastric emptying rate was not diminished. Therefore, this method can be used as an appropriate nutritional support in intensive care unit.

  11. The effect of graphene nanoplatelet volume fraction on water graphene nanofluid thermal conductivity and viscosity

    Science.gov (United States)

    Bahaya, Bernard

    The aim of this thesis is to study the improvement of heat transfer in graphene-water nanofluids. Experiments were conducted with graphene nanoplatelets (GNP) to study the relative benefit of the thermal conductivity improvement in relationship to the potential detriment when considering the effect that more GNP dispersed in the water increases the viscosity of the resulting suspension relative to that of the water. A maximum enhancement ratio for GNP nanofluid thermal conductivity over water was 1.43 at a volume fraction of 0.014. Based upon GNP aspect ratios confirmed in sizing measurements, the DEM model presented by Chu et al., (2012) appears to describe the experimental results of this study when using a fitted interfacial resistance value of 6.25 E -8 m2 K W-1. The well-known Einstein viscosity model for spheres dispersed in fluids was shown to under predict the experimental data. Adjusting the intrinsic model term for spheres from a value of 2.5 to a fitted value of 1938 representative for the GNP of this study provided much closer agreement between measured and predicted values. Heat transfer is a nonlinear function of viscosity and thermal conductivity and heat transfer is predicted to decrease for GNP nanofluids when compared to water alone. Hence the use of nanofluids to enhance heat transfer processes appears not to be viable.

  12. Sensitivity and specificity of the Eating Assessment Tool and the Volume-Viscosity Swallow Test for clinical evaluation of oropharyngeal dysphagia

    Science.gov (United States)

    Rofes, L; Arreola, V; Mukherjee, R; Clavé, P

    2014-01-01

    Background Oropharyngeal dysphagia (OD) is an underdiagnosed digestive disorder that causes severe nutritional and respiratory complications. Our aim was to determine the accuracy of the Eating Assessment Tool (EAT-10) and the Volume-Viscosity Swallow Test (V-VST) for clinical evaluation of OD. Methods We studied 120 patients with swallowing difficulties and 14 healthy subjects. OD was evaluated by the 10-item screening questionnaire EAT-10 and the bedside method V-VST, videofluoroscopy (VFS) being the reference standard. The V-VST is an effort test that uses boluses of different volumes and viscosities to identify clinical signs of impaired efficacy (impaired labial seal, piecemeal deglutition, and residue) and impaired safety of swallow (cough, voice changes, and oxygen desaturation ≥3%). Discriminating ability was assessed by the AUC of the ROC curve and sensitivity and specificity values. Key Results According to VFS, prevalence of OD was 87%, 75.6% with impaired efficacy and 80.9% with impaired safety of swallow including 17.6% aspirations. The EAT-10 showed a ROC AUC of 0.89 for OD with an optimal cut-off at 2 (0.89 sensitivity and 0.82 specificity). The V-VST showed 0.94 sensitivity and 0.88 specificity for OD, 0.79 sensitivity and 0.75 specificity for impaired efficacy, 0.87 sensitivity and 0.81 specificity for impaired safety, and 0.91 sensitivity and 0.28 specificity for aspirations. Conclusions & Inferences Clinical methods for screening (EAT-10) and assessment (V-VST) of OD offer excellent psychometric proprieties that allow adequate management of OD. Their universal application among at-risk populations will improve the identification of patients with OD at risk for malnutrition and aspiration pneumonia. PMID:24909661

  13. Density-viscosity product of small-volume ionic liquid samples using quartz crystal impedance analysis.

    Science.gov (United States)

    McHale, Glen; Hardacre, Chris; Ge, Rile; Doy, Nicola; Allen, Ray W K; MacInnes, Jordan M; Bown, Mark R; Newton, Michael I

    2008-08-01

    Quartz crystal impedance analysis has been developed as a technique to assess whether room-temperature ionic liquids are Newtonian fluids and as a small-volume method for determining the values of their viscosity-density product, rho eta. Changes in the impedance spectrum of a 5-MHz fundamental frequency quartz crystal induced by a water-miscible room-temperature ionic liquid, 1-butyl-3-methylimiclazolium trifluoromethylsulfonate ([C4mim][OTf]), were measured. From coupled frequency shift and bandwidth changes as the concentration was varied from 0 to 100% ionic liquid, it was determined that this liquid provided a Newtonian response. A second water-immiscible ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [C4mim][NTf2], with concentration varied using methanol, was tested and also found to provide a Newtonian response. In both cases, the values of the square root of the viscosity-density product deduced from the small-volume quartz crystal technique were consistent with those measured using a viscometer and density meter. The third harmonic of the crystal was found to provide the closest agreement between the two measurement methods; the pure ionic liquids had the largest difference of approximately 10%. In addition, 18 pure ionic liquids were tested, and for 11 of these, good-quality frequency shift and bandwidth data were obtained; these 12 all had a Newtonian response. The frequency shift of the third harmonic was found to vary linearly with square root of viscosity-density product of the pure ionic liquids up to a value of square root(rho eta) approximately 18 kg m(-2) s(-1/2), but with a slope 10% smaller than that predicted by the Kanazawa and Gordon equation. It is envisaged that the quartz crystal technique could be used in a high-throughput microfluidic system for characterizing ionic liquids.

  14. Study of apparent molal volume and viscosity of mutual citric acid and disodium hydrogen orthophosphate aqueous systems

    Indian Academy of Sciences (India)

    Man Singh

    2006-05-01

    Fundamental properties, density () and viscosity (), of citric acid (CA) and disodium hydrogen orthophosphate (DSP) at various strengths were obtained at different temperatures. The and values were used to determine apparent molal volumes and viscosity of systems. The , and values were regressed against molality for ρ0, 0 and $V^{0}_{\\phi}$f, the limiting constants at infinite dilution ( → 0) forionic and molecular interactions. The ρ0 and $V^{0}_{\\phi}$f of aq. acids are higher than those of aq. DSP and the viscosity of DSP is higher than that of aq. CA. Examination of ρ0 and $V^{0}_{\\phi}$ functions indicates that mutual compositions of CA and DSP counterbalance concentration and temperature effects on pH in bioprocesses.

  15. Excess molar volumes and viscosities of binary mixtures of 1,2-diethoxyethane with chloroalkanes at 298 15 K

    Indian Academy of Sciences (India)

    Amalendu Pal; Rakesh Kumar Bhardwaj

    2001-06-01

    Excess molar volumes ($V^{E}_{m}$) and viscosities () of the binary mixtures of 1,2-diethoxyethane with di-, tri- and tetrachloromethane have been measured at 298.15 K and atmospheric pressure over the entire mole fraction range. The deviations in viscosities (ln) and excess energies of activation ( *) for viscous flow have been calculated from the experimental data. The Prigogine-Flory-Patterson (PFP) model has been used to calculate $V^{E}_{m}$, and the results have been compared with experimental data. The Bloomfield and Dewan model has been used to calculate viscosity coefficients and these have also been compared with experimental data for the three mixtures. The results have been discussed in terms of dipole-dipole interactions between 1,2-diethoxyethane and chloroalkanes and their magnitudes decreasing with the dipole character of the molecules. A short comparative study with results for mixtures with polyethers and chloroalkanes is also described.

  16. Experimental contribution to the understanding of the dynamics of spreading of Newtonian fluids: effect of volume, viscosity and surfactant.

    Science.gov (United States)

    Roques-Carmes, Thibault; Mathieu, Vincent; Gigante, Alexandra

    2010-04-01

    The dynamics of drop spreading of glycerol-water mixtures with and without surfactant on hydrophilic glass surfaces has been investigated. The influence of different factors, such as viscosity, drop volume and non-ionic alkyl (8-16) glucoside (Plantacare) surfactant concentration on the number and the nature of the spreading regimes is systematically investigated. More than 25 spreading experiments have been performed in order to obtain clear trends. The results confirm the existence of several spreading regimes for the duration of an experiment (200 s). For each regime, the radius can be expressed by a power law of the form R=Kt(n). Both n and K are necessary to identify the regime. The experimental data are compared with the analytical predictions of the combined theory of spreading. One of the main results of this study is that the nature of the regimes is strongly affected by the drop volume, the viscosity and the surfactant concentration. This behavior is not predicted by the theory. For drop volume less than or equal to 15 microL, a succession of two different regimes which depend on the viscosity and surfactant concentration are observed in the following order: a molecular-kinetic regime followed by a hydrodynamic regime (for high viscosity in the presence of surfactant) or a hydrodynamic regime and lastly a final asymptotic regime corresponding to a long relaxation time to equilibrium (for high viscosity in absence of surfactant and for low viscosity regardless of the presence of surfactant). The spreading follows quantitatively the predictions of the theory. Our results demonstrate that the theory is still valid for low viscosity liquids and in the presence of surfactant. The contact angle for which the crossover between molecular-kinetic regime and hydrodynamic regime occurs is thoroughly estimated since the theories do not allow the exact calculation of this value. Here for the first time, an empirical power law exponent (n=0.08+/-0.05) is proposed for

  17. Excess volumes and excess viscosities of binary mixtures of some cyclic ethers + bromocyclohexane at 298.15 and 313.15 K

    Science.gov (United States)

    Rodríguez, S.; Lafuente, C.; Carrión, J. A.; Royo, F. M.; Urieta, J. S.

    1996-11-01

    Excess Volumes, V E, and excess viscosities, η E, at 293.15 and 313.15 K are reported for binary mixtures of some cyclic ethers (tetrahydrofuran, tetrahydropyran, 2-methyltetrahydrofuran and 2,5-dimethyltetrahydrofuran) + bromocyclohexane. These properties were obtained from density and viscosity measurements. γ E and η E show negatives values for all the mixtures.

  18. Volume-of-fluid simulations in microfluidic T-junction devices: Influence of viscosity ratio on droplet size

    Science.gov (United States)

    Nekouei, Mehdi; Vanapalli, Siva A.

    2017-03-01

    We used volume-of-fluid (VOF) method to perform three-dimensional numerical simulations of droplet formation of Newtonian fluids in microfluidic T-junction devices. To evaluate the performance of the VOF method we examined the regimes of drop formation and determined droplet size as a function of system parameters. Comparison of the simulation results with four sets of experimental data from the literature showed good agreement, validating the VOF method. Motivated by the lack of adequate studies investigating the influence of viscosity ratio (λ) on the generated droplet size, we mapped the dependence of drop volume on capillary number (0.001 1. In addition, we find that at a given capillary number, the size of droplets does not vary appreciably when λ 1. We develop an analytical model for predicting the droplet size that includes a viscosity-dependent breakup time for the dispersed phase. This improved model successfully predicts the effects of the viscosity ratio observed in simulations. Results from this study are useful for the design of lab-on-chip technologies and manufacture of microfluidic emulsions, where there is a need to know how system parameters influence the droplet size.

  19. Thermophysical Properties of Matter - the TPRC Data Series. Volume 11. Viscosity

    Science.gov (United States)

    1975-01-01

    such missing information, ranging from empitical pendia of empirical relations useful in estimation of procedures to detailed theoretical...55 0.0000 8.76 2 115-G(C) 1 Adzumi, H. 293.2 0.0000 9.24 H 2 : electrolysis of water, dried and 0. 2083 10. 62 traces of oxygen removed by passing...137, 176-92, 1928. 22 7029 Braune, H. and Linke , R., "The Viscosity of Gases and Vapors. Il. Influence of the Dipole Moment on the Magnitude of the

  20. A study on developing customized bolus using 3D prints

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Sang Min; Yang, Jin Ho; Lee, Seung Hyun; Kim, Jin Uk; Yeom, Du Seok [Dept. of Proton Therapy Center, National Cancer Center, Ilsan (Korea, Republic of)

    2015-06-15

    3D Printers are used to create three-dimensional models based on blueprints. Based on this characteristic, it is feasible to develop a bolus that can minimize the air gap between skin and bolus in radiotherapy. This study aims to compare and analyze air gap and target dose at the branded 1 cm bolus with the developed customized bolus using 3D printers. RANDO phantom with a protruded tumor was used to procure images using CT simulator. CT DICOM file was transferred into the STL file, equivalent to 3D printers. Using this, customized bolus molding box (maintaining the 1 cm width) was created by processing 3D printers, and paraffin was melted to develop the customized bolus. The air gap of customized bolus and the branded 1 cm bolus was checked, and the differences in air gap was used to compare D{sub max}, D{sub min}, D{sub mean}, D{sub 95%} and V{sub 95%} in treatment plan through Eclipse. Customized bolus production period took about 3 days. The total volume of air gap was average 3.9 cm{sup 3} at the customized bolus. And it was average 29.6cm{sup 3} at the branded 1 cm bolus. The customized bolus developed by the 3D printer was more useful in minimizing the air gap than the branded 1 cm bolus. In the 6 MV photon, at the customized bolus, D{sub max}, D{sub min}, D{sub mean}, D{sub 95%}, V{sub 95%} of GTV were 102.8%, 88.1%, 99.1%, 95.0%, 94.4% and the D{sub max}, D{sub min}, D{sub mean}, D{sub 95%}, V{sub 95%} of branded 1 cm bolus were 101.4%, 92.0%, 98.2%, 95.2%, 95.7%, respectively. In the proton, at the customized bolus, D{sub max}, D{sub min}, D{sub mean}, D{sub 95%}, V{sub 95%} of GTV were 104.1%, 84.0%, 101.2%, 95.1%, 99.8% and the D{sub max}, D{sub min}, D{sub mean}, D{sub 95%}, V{sub 95%} of branded 1cm bolus were 104.8%, 87.9%, 101.5%, 94.9%, 99.9%, respectively. Thus, in treatment plan, there was no significant difference between the customized bolus and 1 cm bolus. However, the normal tissue nearby the GTV showed relatively lower radiation dose. The

  1. Effects of large gut volume in gelatinous zooplankton: ingestion rate, bolus production and food patch utilization by the jellyfish Sarsia tubulosa

    DEFF Research Database (Denmark)

    Hansson, L.J.; Kiørboe, Thomas

    2006-01-01

    Many gelatinous zooplankton consume a large amount of prey and have stomach volumes much greater than the volume of individual prey. We suggest that jellyfish can use their voluminous stomach as a buffering food-accumulating organ that allows the organism to feed at maximum clearance rate in a wide...

  2. SU-C-213-06: Dosimetric Verification of 3D Printed Electron Bolus

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, K; Corbett, M; Pelletier, C; Huang, Z; Feng, Y; Jung, J [East Carolina Univ, Greenville, NC (United States)

    2015-06-15

    Purpose: To determine the dosimetric effect of 3D printed bolus in an anthropomorphic phantom. Methods: Conformable bolus material was generated for an anthropomorphic phantom from a DICOM volume. The bolus generated was a uniform expansion of 5mm applied to the nose region of the phantom, as this is a difficult area to uniformly apply bolus clinically. A Printrbot metal 3D Printer using PLA plastic generated the bolus. A 9MeV anterior beam with a 5cm cone was used to deliver dose to the nose of the phantom. TLD measurements were compared to predicted values at the phantom surface. Film planes were analyzed for the printed bolus, a standard 5mm bolus sheet placed on the phantom, and the phantom with no bolus applied to determine depth and dose distributions. Results: TLDs measured within 2.5% of predicted value for the 3D bolus. Film demonstrated a more uniform dose distribution in the nostril region for the 3d printed bolus than the standard bolus. This difference is caused by the air gap created around the nostrils by the standard bolus, creating a secondary build-up region. Both demonstrated a 50% central axis dose shift of 5mm relative to the no bolus film. HU for the bolus calculated the PLA electron density to be ∼1.1g/cc. Physical density was measured to be 1.3g/cc overall. Conclusion: 3D printed PLA bolus demonstrates improved dosimetric performance to standard bolus for electron beams with complex phantom geometry.

  3. Apparent molar volumes and viscosity B-coefficients of caffeine in aqueous thorium nitrate solutions at T = (298.15, 308.15, and 318.15) K

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, Biswajit, E-mail: biswachem@gmail.co [Department of Chemistry, University of North Bengal, Darjeeling 734013 (India); Roy, Pran Kumar; Sarkar, Bipul Kumar; Brahman, Dhiraj [Department of Chemistry, University of North Bengal, Darjeeling 734013 (India); Roy, Mahendra Nath, E-mail: mahendraroy2002@yahoo.co.i [Department of Chemistry, University of North Bengal, Darjeeling 734013 (India)

    2010-03-15

    Apparent molar volumes phi{sub V} and viscosity B-coefficients for caffeine in (0.00, 0.03, 0.05, and 0.07) mol . dm{sup -3} aqueous thorium nitrate, Th(NO{sub 3}){sub 4}, solutions were determined from solution density and viscosity measurements over the temperature range (298.15 to 318.15) K as function of concentration of caffeine and the relation: phi{sub V}{sup 0}=a{sub 0}+a{sub 1}T+a{sub 2}T{sup 2}, have been used to describe the temperature dependence of the standard partial molar volumes phi{sub V}{sup 0}. These results have been used to deduce the standard volumes of transfer DELTAphi{sub V}{sup 0} and viscosity B-coefficients of transfer DELTAB for caffeine from water to aqueous Th(NO{sub 3}){sub 4} solutions for rationalizing various interactions in the ternary solutions. The structure-making or breaking ability of caffeine has been discussed in terms of the sign of (delta{sup 2}phi{sub V}{sup 0}/deltaT{sup 2}){sub P}. The Friedman-Krishnan co-sphere model was used to explain the transfer volume of caffeine with increasing Th(NO{sub 3}){sub 4} molarity. The activation parameters of viscous flow for the ternary solutions were also discussed in terms of transition state theory.

  4. Excess molar volumes and viscosities of binary mixtures of some polyethers with 1-propanol at 288.15, 298.15, and 308.15 K

    Indian Academy of Sciences (India)

    Amalendu Pal; Anil Kumar

    2004-01-01

    Excess molar volumes ($V_{m}^{E}$) and viscosities () have been measured as a function of composition for binary liquid mixtures of 1-propanol, C3H7OH, with diethylene glycol diethyl ether (bis(2-ethoxyethyl)ether), C2H5(OC2H4)2OC2H5, and diethylene glycol dibutyl ether (bis(2-butoxyethyl)ether), C4H9(OC2H4)2OC4H9, at 288.15, 298.15, and 308.15 K and at atmospheric pressure. The excess volume results included the following mixing quantities at all range of concentrations and at equimolar concentrations: , volume expansivity; ( $V^{E}_{m}$/ ), and ( /) at 298.15 K. The obtained results were then compared with the calculated values by using the Flory theory of liquid mixtures. The theory predicts the values rather well, while the calculated values of ( $V^{E}_{m}$/ ) and ( /) show variation with alkyl chain length of the polyether. The results are discussed in terms of order or disorder creation. From the viscosity data, deviations in viscosity ( ) have been calculated. These values are negative over the entire range of composition. The results for $V^{E}_{m}$, and are discussed in terms of interaction between components.

  5. Excess Molar Volumes and Viscosities for Binary Mixtures of 1-Alkoxypropan-2-ols with 1-Butanol,and 2-Butanol at 298.15 K and Atmospheric Pressure

    Institute of Scientific and Technical Information of China (English)

    PAL Amalendu; GABA Rekha

    2007-01-01

    Excess molar volumes VEm and kinematic viscosities v have been measured as a function of composition for binary mixtures of propylene glycol monomethyl ether (1-methoxy-2-propanol),MeOCH2CH(OH)Me,propylene glycol monoethyl ether (1-ethoxy-2-propanol), EtOCH2CH(OH)Me,propylene glycol monopropyl ether (1-propoxy-2-propanol), PrOCH2CH(OH)Me, propylene glycol monobutyl ether (1-butoxy-2-propanol),BuOCH2CH(OH)Me,and propylene glycol tert-butyl ether (1-tert-butoxy-2-propanol),t-BuOCH2CH(OH)Me with 1-butanol,and 2-butanol,at 298.15 K and atmospheric pressure.The excess molar volumes are negative across the entire range of composition for all the systems with 1-butanol,and positive for the systems 2-butanol+1-methoxy-2-propanol,and +1-propoxy-2-propanol,negative for the systems 2-butanol+1-butoxy-2-propanol,and change sign for the systems 2-butanol+1-ethoxy-2-propanol,and +1-tert-butoxy-2-propanol.From the experimental data,the deviation in dynamic viscosity η from Σxiηi has been calculated.Both excess molar volumes and viscosity deviations have been correlated using a Redlich-Kister type polynomial equation by the method of least-squares for the estimation of the binary coefficients and the standard errors.

  6. Measurement and COrrelation on Viscosity and Apparent Molar Volume of Ternary System for L—ascorbic Acid in Aqueous D—Glucose and Sucrose Solutions

    Institute of Scientific and Technical Information of China (English)

    赵长伟; 马沛生

    2003-01-01

    Visosities and densities at ,several temperatures from 293.15 K to 313.15K are reported for L-ascorbic acid in aqueous glucose and sucrose solutions at different concentrations.The parameters of density,Viscosity coefficient B and partial molar volume are calculated by regression.The experimental results show that densities and viscositis decrease as temperature increases at the same solute and solvent (glucose and sucrose aueous solution)concentrations,and increase with concentration of glucose and sucrose at the same solute concentration and temperature,B increases with concentration of glucose and sucrose and temaperature,L-ascorbic acid is sturcture-breaker or structure-making for the glucose and sucrose aqueous solutions ,Furthermore,the solute-solvent interactions in ternary systems of water-glucose-electrolyte and water-sucrose-electrolyte are discussed.

  7. 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.

  8. Excess molar volumes and viscosities of (1,1,2,2-tetrabromoethane + 1-alkanols) at T = (293.15 and 303.15) K

    Energy Technology Data Exchange (ETDEWEB)

    Al-Hayan, M.N.M. [Department of Chemical Engineering Technology, College of Technological Studies, P.O. Box 42325, Shuwaik 70654 (Kuwait)]. E-mail: hayan@paaet.edu.kw; Abdul-latif, Abdul-Haq M. [Department of Chemical Engineering Technology, College of Technological Studies, P.O. Box 42325, Shuwaik 70654 (Kuwait)

    2006-01-15

    Density and viscosity measurements for binary mixtures of (1,1,2,2-tetrabromoethane + 1-pentanol, or + 1-hexanol, or + 1-heptanol, or + 1-octanol, or + 1-decanol) at T = (293.15 and 303.15) K, have been conducted at atmospheric pressure. The excess molar volumes V {sup E}, have been calculated from the experimental measurements, and the results were fitted to Redlich-Kister equation. The viscosity data were correlated with the model of Grunberg and Nissan, and McAllister four-body model. The excess molar volumes of (1,1,2,2-tetrabromoethane + 1-pentanol, or + 1-haxanol, or + 1-heptanol, or + 1-octanol) had a sigmoidal shape and the values varied from negative to positive with the increase in the molar fraction of 1,1,2,2-tetrabromoethane. The remaining binary mixture of (1,1,2,2-tetrabromoethane + 1-decanol) was positive over the entire composition range. The effects of the 1-alkanol chain length as well as the temperature on the excess molar volume have been studied. The results have been qualitatively used to explain the molecular interaction between the components of these mixtures.

  9. Electronic bolus design impacts on administration.

    Science.gov (United States)

    Hentz, F; Umstätter, C; Gilaverte, S; Prado, O R; Silva, C J A; Monteiro, A L G

    2014-06-01

    Electronic identification of animals has become increasingly important worldwide to improve and ensure traceability. In warm and hot climates, such as Brazil, boluses can have advantages over ear tags as the internal devices reduce the risks of ear tag losses, tissue damage, and lesions on the ear. Electronic boluses, however, are often perceived as having negative characteristics, including reported difficulties of administration in small ruminants. This paper describes the factors associated with bolus design that affect the swallowing of a bolus in sheep. Other factors that might influence bolus swallowing time have also been considered. In addition, the effect of bolus design on its performance was evaluated. A total of 56 Suffolk ewes were used to assess the ease of administration and retention of 3 types of electronic ruminal boluses (mini, 11.5 × 58.0 mm and 21.7 g; small, 14.8 × 48.5 mm and 29.5 g; standard, 19.3 × 69.8 mm and 74.4 g) during a whole productive year, including pregnancy and lamb suckling. Ewe age (5.6 ± 2.3 yr) and weight (85.07 ± 8.2 kg BW) were recorded, as well as time for bolus swallowing. The deglutition of the bolus and any resulting blockages in the esophagus were monitored by visual observations. Retention and readability of the boluses were regularly monitored for d 1, wk 1, mo 1, and every mo until 1 yr. Time for bolus swallowing differed substantially with bolus type and was greater (P 0.05). The bolus o.d. and length were positively correlated with swallowing time (P electronic boluses showed 100% retention rate, and at 12 mo, bolus retention was 100%, 94.5%, and 100% for mini, small, and standard boluses, respectively (P > 0.05). At 12 mo, all boluses showed 100% readability, except for small boluses, which had a readability of 94.5%. In conclusion, bolus design affected swallowing time and bolus readability. A reduction in boluses length and o.d. needs to be carried out to provide ease of administration and for boluses to

  10. Utilization of custom electron bolus in head and neck radiotherapy.

    Science.gov (United States)

    Kudchadker, R J; Antolak, J A; Morrison, W H; Wong, P F; Hogstrom, K R

    2003-01-01

    Conventional methods of treating superficial head and neck tumors, such as the wedge pair technique or the use of multiple electron fields of varying energies, can result in excellent tumor control. However, in some cases, these techniques irradiate healthy tissue unnecessarily and/or create hot and cold spots in junction regions, particularly in patients with complex surface contour modification or varying planning target volume (PTV) thickness. The objective of this work is to demonstrate how bolus electron conformal therapy can be used for these patients. Two patients treated using this technique are presented. The first patient was diagnosed with malignant fibrous histiocytoma involving the right ear concha and was treated with 12-MeV electrons. The second patient was diagnosed with acinic cell carcinoma of the left parotid gland and was treated with 20-MeV electrons after having undergone a complete parotidectomy. Each patient's bolus was designed using bolus design tools implemented in an in-house treatment-planning system (TPS). The bolus was fabricated using a computer-controlled milling machine. As part of the quality assurance process to ensure proper fabrication and placement of the bolus, the patients underwent a second computed tomography (CT) scan with the bolus in place. Using that data, the final dose distribution was computed using the Philips Pinnacle(3) TPS (Philips Medical Systems, Andover, MA). Results showed that the 90% isodose surface conformed well to the PTV and that the dose to critical structures such as cord, brain, and lung was well below tolerance limits. Both patients showed no evidence of disease six months post-radiotherapy. In conclusion, electron bolus conformal therapy is a viable option for treating head and neck tumors, particularly patients having a variable thickness PTV or surface anatomy with surgical defects.

  11. Volume-translated cubic EoS and PC-SAFT density models and a free volume-based viscosity model for hydrocarbons at extreme temperature and pressure conditions

    Energy Technology Data Exchange (ETDEWEB)

    Burgess, Ward A.; Tapriyal, Deepak; Morreale, Bryan D.; Soong, Yee; Baled, Hseen O.; Enick, Robert M.; Wu, Yue; Bamgbade, Babatunde A.; McHugh, Mark A.

    2013-12-01

    This research focuses on providing the petroleum reservoir engineering community with robust models of hydrocarbon density and viscosity at the extreme temperature and pressure conditions (up to 533 K and 276 MPa, respectively) characteristic of ultra-deep reservoirs, such as those associated with the deepwater wells in the Gulf of Mexico. Our strategy is to base the volume-translated (VT) Peng–Robinson (PR) and Soave–Redlich–Kwong (SRK) cubic equations of state (EoSs) and perturbed-chain, statistical associating fluid theory (PC-SAFT) on an extensive data base of high temperature (278–533 K), high pressure (6.9–276 MPa) density rather than fitting the models to low pressure saturated liquid density data. This high-temperature, high-pressure (HTHP) data base consists of literature data for hydrocarbons ranging from methane to C{sub 40}. The three new models developed in this work, HTHP VT-PR EoS, HTHP VT-SRK EoS, and hybrid PC-SAFT, yield mean absolute percent deviation values (MAPD) for HTHP hydrocarbon density of ~2.0%, ~1.5%, and <1.0%, respectively. An effort was also made to provide accurate hydrocarbon viscosity models based on literature data. Viscosity values are estimated with the frictional theory (f-theory) and free volume (FV) theory of viscosity. The best results were obtained when the PC-SAFT equation was used to obtain both the attractive and repulsive pressure inputs to f-theory, and the density input to FV theory. Both viscosity models provide accurate results at pressures to 100 MPa but experimental and model results can deviate by more than 25% at pressures above 200 MPa.

  12. Excess Molar Volume,Viscosity and Heat Capacity for the Mixture of 1,2—Propanediol—Water at Different Temperatures

    Institute of Scientific and Technical Information of China (English)

    杨长生; 马沛生; 唐多强; 靳凤民

    2003-01-01

    Experimental densities,viscosities and heat capacities at different emperatures were presented over the entire mole fraction range for the binary mixture of 1,2-propanediol and water,Density values were used in the determination of excess molar volumes,VE,At the same time,the excess viscosity was in vestigated,The values of VE and ηE were fitted to the Redlich-kister equation.Good agreement was observed,The excess volumes are negative over the entire range of composition.They show an U-shaped-concentration dependence and decrease in abolute values with increase of temperature,Values of ηE are negative over the entire range of the composition,and has a trend very similar to that of VE ,The analysis shows that at any temperature the specific heat of mixture is a linear function of the composition as x1>20%,All the extended lines intersect at one point.An empirical equation is obtained to calculate the specific heat to mixture at any composition and temperature in the experimental range.

  13. Bolus characteristics based on Magnetic Resonance Angiography

    Directory of Open Access Journals (Sweden)

    Bi Xiaoming

    2006-10-01

    Full Text Available Abstract Background A detailed contrast bolus propagation model is essential for optimizing bolus-chasing Computed Tomography Angiography (CTA. Bolus characteristics were studied using bolus-timing datasets from Magnetic Resonance Angiography (MRA for adaptive controller design and validation. Methods MRA bolus-timing datasets of the aorta in thirty patients were analyzed by a program developed with MATLAB. Bolus characteristics, such as peak position, dispersion and bolus velocity, were studied. The bolus profile was fit to a convolution function, which would serve as a mathematical model of bolus propagation in future controller design. Results The maximum speed of the bolus in the aorta ranged from 5–13 cm/s and the dwell time ranged from 7–13 seconds. Bolus characteristics were well described by the proposed propagation model, which included the exact functional relationships between the parameters and aortic location. Conclusion The convolution function describes bolus dynamics reasonably well and could be used to implement the adaptive controller design.

  14. Evaluation of Pharyngeal Function between No Bolus and Bolus Propofol Induced Sedation for Advanced Upper Endoscopy

    Directory of Open Access Journals (Sweden)

    Shinsuke Kiriyama

    2014-01-01

    Full Text Available This study aimed to assess pharyngeal function between no bolus and bolus propofol induced sedation during gastric endoscopic submucosal dissection. A retrospective study was conducted involving consecutive gastric cancer patients. Patients in the no bolus group received a 3 mg/kg/h maintenance dose of propofol after the initiation of sedation without bolus injection. All patients in the bolus group received the same maintenance dose of propofol with bolus 0.5 mg/kg propofol injection. Pharyngeal functions were evaluated endoscopically for the first 5 min following the initial administration of propofol. Fourteen patients received no bolus propofol induction and 13 received bolus propofol induction. Motionless vocal cords were observed in 2 patients (14% in the no bolus group and 3 (23% in the bolus group. Trachea cartilage was not observed in the no bolus group but was apparent in 6 patients (46% in the bolus group (P<0.01. Scope stimulated pharyngeal reflex was observed in 11 patients (79% in the no bolus group and in 3 (23% in the bolus group (P<0.01. Propofol induced sedation without bolus administration preserves pharyngeal function and may constitute a safer sedation method than with bolus.

  15. 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.

  16. 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.

  17. Excess molar volumes and deviation in viscosities of binary liquid mixtures of acrylic esters with hexane-1-ol at 303.15 and 313.15 K

    Directory of Open Access Journals (Sweden)

    Sujata S. Patil

    2014-12-01

    Full Text Available Densities and viscosities for the four binary liquid mixtures of methyl acrylate, ethyl acrylate, butyl acrylate and methyl methacrylate with hexane-1-ol at temperatures 303.15 and 313.15 K and at atmospheric pressure were measured over the entire composition range. These values were used to calculate excess molar volumes and deviation in viscosities which were fitted to Redlich–Kister polynomial equation. Recently proposed Jouyban Acree model was also used to correlate the experimental values of density and viscosity. The mixture viscosities were correlated by several semi-empirical approaches like Hind, Choudhary–Katti, Grunberg–Nissan, Tamura and Kurata, McAllister three and four body model equations. A graphical representation of excess molar volumes and deviation in isentropic compressibility shows positive nature whereas deviation in viscosity shows negative nature at both temperatures for all four binary liquid mixtures. Positive values of excess molar volumes show that volume expansion is taking place causing rupture of H-bonds in self associated alcohols. The results were discussed in terms of molecular interactions prevailing in the mixtures.

  18. Soft-robotic esophageal swallowing as a clinically-inspired bolus rheometry technique

    Science.gov (United States)

    Dirven, Steven; Allen, Jacqueline; (Peter Xu, Weiliang; Cheng, Leo K.

    2017-03-01

    To investigate the impact of viscosity and peristaltic transport parameters on manometric pressure signatures, a reproducible swallowing process is required. Due to inter- and intra-subject variability from swallow to swallow, the human body does not represent an optimal mechanism for such an investigation. A smooth and continuous swallowing soft-robot has been developed to produce biomimetic swallowing trajectories, and is proposed to operate as a bench-top bolus rheometric investigation method. The method compares conventional viscometry and pressure signature findings from robotic swallowing experiments. The robotic aspect of experimentation involved 450 biomimetic swallows (10 repetitions of 45 unique experiments). The method examined swallowing transport in three dimensions: bolus formulation, peristaltic wavelength, and peristaltic velocity, each of which are known to contribute to safe and effective swallowing in vivo. It is found that the pressure gradients and magnitudes are commensurate with clinical reports on biological swallowing, on the order of 100 mmHg peak, however, the relationship between viscosity and pressure signatures is less clear. Bolus transport cannot be predicted as a function of bolus viscosity alone. Traditional viscometric data at 50 s-1, as used in clinical practice, may not be a strong indicator of swallow effort, safety, or efficacy in vivo.

  19. 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.

  20. Dynamic and kinematic viscosities, excess volumes and excess Gibbs energies of activation for viscous flow in the ternary mixture {1- propanol+ N,N-dimethylformamide + chloroform} at temperatures between 293.15 K and 323.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Hassein-bey-Larouci, A., E-mail: hasseinbey@yahoo.fr [Laboratoire Thermodynamique et Modélisation Moléculaire, Faculté de Chimie, Université des Sciences et de la Technologie Houari Boumediene, B.P. 32, El-Alia, 16111 Bab-Ezzouar, Alger (Algeria); Igoujilen, O.; Aitkaci, A. [Laboratoire Thermodynamique et Modélisation Moléculaire, Faculté de Chimie, Université des Sciences et de la Technologie Houari Boumediene, B.P. 32, El-Alia, 16111 Bab-Ezzouar, Alger (Algeria); Segovia, J.J.; Villamañán, M.A. [TERMOCAL Research Group, Escuela de Ingenierías Industriales, Universidad de Valladolid, Paseo del Cauce, 59, 47011 Valladolid (Spain)

    2014-08-10

    Highlights: • Many engineering applications require quantitative thermodynamic data of the fluids. • Excess properties of mixtures are important in the understanding of mixing process. • The results are used to explain the molecular interaction in the mixtures. - Abstract: Dynamic and kinematic viscosities, and densities of the ternary mixture {x_1 propanol + x_2 DMF + x_3 chloroform} and of the three corresponding binary systems have been measured at 293.15, 303.15, 313.15 and 323.15 K and atmospheric pressure. The thermophysical properties, viscosity deviations (Δη), kinematic viscosity (γ), excess Gibbs energies of activation of viscous flow (G*{sup E}) and excess molar volumes (V{sup E}) have been calculated from experimental values of dynamic viscosity, η, and density, ρ. The different results have been correlated by the Redlich–Kister equation for the binary mixtures and the Cibulka equation for equation for the ternary ones.

  1. Studies on Excess Volume, Viscosity, and Speed of Sound of Binary Mixtures of Methyl Benzoate in Ethers at T=(303.15,308.15, and 313.15 K

    Directory of Open Access Journals (Sweden)

    M. V. Rathnam

    2013-01-01

    Full Text Available Densities, viscosities, and speed of sound have been determined at T = (303.15, 308.15, and 313.15 K for the binary mixtures of methyl benzoate with tetrahydrofuran, 1,4-dioxane, anisole, and butyl vinyl ether over the entire range of composition. Using these measured values, excess volume VE, deviation in viscosities Δη, excess Gibb’s free energy of activation for viscous flow ΔG*E, and deviation in isentropic compressibility Δks have been calculated. These calculated binary data have been fitted to Redlich-Kister equation to determine the appropriate coefficients. The values of excess volume VE and deviation in viscosities Δη are negative over the entire range of composition for all the binary systems at the studied temperatures. The behavior of these parameters with composition of the mixture has been discussed in terms of molecular interactions between the components of liquids.

  2. A Patient-Specific Polylactic Acid Bolus Made by a 3D Printer for Breast Cancer Radiation Therapy.

    Science.gov (United States)

    Park, So-Yeon; Choi, Chang Heon; Park, Jong Min; Chun, MinSoo; Han, Ji Hye; Kim, Jung-In

    2016-01-01

    The aim of this study was to assess the feasibility and advantages of a patient-specific breast bolus made using a 3D printer technique. We used the anthropomorphic female phantom with breast attachments, which volumes are 200, 300, 400, 500 and 650 cc. We simulated the treatment for a right breast patient using parallel opposed tangential fields. Treatment plans were used to investigate the effect of unwanted air gaps under bolus on the dose distribution of the whole breast. The commercial Super-Flex bolus and 3D-printed polylactic acid (PLA) bolus were applied to investigate the skin dose of the breast with the MOSFET measurement. Two boluses of 3 and 5 mm thicknesses were selected. There was a good agreement between the dose distribution for a virtual bolus generated by the TPS and PLA bolus. The difference in dose distribution between the virtual bolus and Super-Flex bolus was significant within the bolus and breast due to unwanted air gaps. The average differences between calculated and measured doses in a 200 and 300 cc with PLA bolus were not significant, which were -0.7% and -0.6% for 3mm, and -1.1% and -1.1% for 5 mm, respectively. With the Super-Flex bolus, however, significant dose differences were observed (-5.1% and -3.2% for 3mm, and -6.3% and -4.2% for 5 mm). The 3D-printed solid bolus can reduce the uncertainty of the daily setup and help to overcome the dose discrepancy by unwanted air gaps in the breast cancer radiation therapy.

  3. Bolus-tracking arterial spin labelling: theoretical and experimental results

    Science.gov (United States)

    Kelly, M. E.; Blau, C. W.; Kerskens, C. M.

    2009-03-01

    Arterial spin labelling (ASL) is a magnetic resonance imaging (MRI) technique that can be used to provide a quantitative assessment of cerebral perfusion. Despite the development of a number of theoretical models to facilitate quantitative ASL, some key challenges still remain. The purpose of this study is to develop a novel quantitative ASL method based on a macroscopic model that reduces the number of variables required to describe the physiological processes involved. To this end, a novel Fokker-Planck equation consisting of stochastically varying macroscopic variables was derived from a general Langevin equation. ASL data from the rat brain was acquired using a bolus-tracking ASL protocol where a bolus of labelled spins flowing from an inversion plane in the neck into an imaging plane in the brain can be observed. Bolus durations of 1.5 s, 2.0 s and 3.0 s were used and the solution to the Fokker-Planck equation for the boundary conditions of bolus-tracking ASL was fitted to the experimental data using a least-squares fit. The mean transit time (MTT) and capillary transit time (CTT) were calculated from the first and second moments of the resultant curve respectively and the arterial transit time (ATT) was calculated by subtracting the CTT from the MTT. The average MTT, CTT and ATT values were 1.75 ± 0.22 s, 1.43 ± 0.12 s and 0.32 ± 0.04 s respectively. In conclusion, a new ASL protocol has been developed by combining the theoretical model with ASL experiments. The technique has the unique ability to provide solutions for varying bolus volumes and the generality of the new model is demonstrated by the derivation of additional solutions for the continuous and pulsed ASL (CASL and PASL) techniques.

  4. Study on the Change of Refractive Index on Mixing, Excess Molar Volume and Viscosity Deviation for Aqueous Solution of Methanol, Ethanol, Ethylene Glycol, 1-Propanol and 1, 2, 3-Propantriol at T = 292.15 K and Atmospheric Pressure

    Directory of Open Access Journals (Sweden)

    Fardad Koohyar

    2012-08-01

    Full Text Available For aqueous solutions of methanol, ethanol, ethylene glycol, 1-propanol and 1, 2, 3-propantriol the change of refractive indices on mixing, excess molar volumes and viscosity deviations were calculated from the experimental data at 292.15 K. These experimental data (refractive indices, densities and viscosities were measured over the whole mole fractions range in atmospheric pressure and at T = 292.15 K. For these mixtures, excess thermodynamic properties have been correlated with the Redlich-Kister polynomial equation (and experimental equation to derive the coefficients and standard errors.

  5. Clinical application of 3D-printed-step-bolus in post-total-mastectomy electron conformal therapy.

    Science.gov (United States)

    Park, Kwangwoo; Park, Sungjin; Jeon, Mi-Jin; Choi, Jinhyun; Kim, Jun Won; Cho, Yoon Jin; Jang, Won-Seok; Keum, Yo Sup; Lee, Ik Jae

    2017-04-11

    The 3D-printed boluses were used during the radiation therapy of the chest wall in six patients with breast cancer after modified radical mastectomy (MRM). We measured the in-vivo skin doses while both conventional and 3D-printed boluses were placed on the chest wall and compared the mean doses delivered to the ipsilateral lung and the heart. The homogeneity and conformity of the dose distribution in the chest wall for both types of boluses were also evaluated. The uniformity index on the chest skin was improved when the 3D-printed boluses were used, with the overall average skin dose being closer to the prescribed one in the former case (-0.47% versus -4.43%). On comparing the dose-volume histogram (DVH), it was found that the 3D-printed boluses resulted in a reduction in the mean dose to the ipsilateral lung by up to 20%. The precision of dose delivery was improved by 3% with the 3D-printed boluses; in contrast, the conventional step bolus resulted in a precision level of 5%. In conclusion, the use of the 3D-printed boluses resulted in better dose homogeneity and conformity to the chest wall as well as the sparing of the normal organs, especially the lung. This suggested that their routine use on the chest wall as a therapeutic approach during post-mastectomy radiation therapy offers numerous advantages over conventional step boluses.

  6. Micropropagation of Gerbera (Gerbera jamesonii Bolus).

    Science.gov (United States)

    Minerva, Ghani; Kumar, Surinder

    2013-01-01

    Gerbera (Gerbera jamesonii Bolus) is one of the most popular ornamental flowers worldwide and used both as cut flower and potted plant. Some of them show excellent agronomic characters such as color, floral diameter, stem length, and vigor, which make this plant of commercial importance. Conventionally, multiplication is done through seeds or rhizome cuttings. Rapid multiplication of elite cultivars of Gerbera, with improved agronomic traits, has been achieved by using both direct and indirect tissue culture methods. Direct shoot regeneration was accomplished from stem apices on MS medium supplemented with 1 mg/L 6-benzyladenine (BA) and 1 mg/L kinetin. Indirect shoot induction succeeded from callus differentiation has been achieved on MS medium containing 2 mg/L 2,4-dichlorophenoxyacetic acid, 0.5 mg/L indole-3-acetic acid, and 2 mg/L BA. The in vitro shoots, 4-5 cm long, were rooted by quick dipping the shoot bases for 3-5 s in 2,000 mg/L indole-3-butyric acid solution followed by transfer to the pots containing farmyard manure, soil, and sand (1:1:1 by volume). Initially, in vitro plantlets were covered with glass jars to maintain a high relative humidity (85-90%). As soon as new shoot growth begins, relative humidity is decreased by exposing them to the open environmental conditions prior transferring to the glasshouse. Indirect shoot regeneration increased the frequency of somaclonal variations. The selected somaclones were used in developing new and novel cultivars.

  7. Ultrasound perfusion analysis combining bolus-tracking and burst-replenishment.

    Science.gov (United States)

    Jirik, Radovan; Nylund, Kim; Gilja, Odd H; Mezl, Martin; Harabis, Vratislav; Kolar, Radim; Standara, Michal; Taxt, Torfinn

    2013-02-01

    A new signal model and processing method for quantitative ultrasound perfusion analysis is presented, called bolus-and-burst. The method has the potential to provide absolute values of blood flow, blood volume, and mean transit time. Furthermore, it provides an estimate of the local arterial input function which characterizes the arterial tree, allowing accurate estimation of the bolus arrival time. The method combines two approaches to ultrasound perfusion analysis: bolus-tracking and burst-replenishment. A pharmacokinetic model based on the concept of arterial input functions and tissue residue functions is used to model both the bolus and replenishment parts of the recording. The pharmacokinetic model is fitted to the data using blind deconvolution. A preliminary assessment of the new perfusion-analysis method is presented on clinical recordings.

  8. Excess Molar Volumes and Viscosities for the Binary Mixtures of n-Octane, n-Decane, n-Dodecane, and n-Tetradecane with Octan-2-ol at 298.15 K

    Directory of Open Access Journals (Sweden)

    Arvind R. Mahajan

    2013-01-01

    Full Text Available Experimental values of densities (ρ and viscosities (η in the binary mixtures of n-octane, n-decane, n-dodecane, and n-tetradecane with octan-2-ol are presented over the whole range of mixture composition at T=298.15 K. From these data, excess molar volume (VmE, deviations in viscosity (Δη, and excess Gibbs free energy of activation ΔG∗E have been calculated. These results were fitted to Redlich-Kister polynomial equations to estimate the binary coefficients and standard errors. Jouyban-Acree model is used to correlate the experimental values of density and viscosity at T=298.15 K. The values of VmE have been analyzed using Prigogine-Flory-Patterson (PFP theory. The results of the viscosity composition are discussed in the light of various viscosity equations suggested by Grunberg-Nissan, Tamara and Kurata, Hind et al., Katti and Chaudhri, Heric, Heric and Brewer, and McAllister multibody model. The values of Δlnη have also been analyzed using Bloomfield and Dewan model. The experiments on the constituted binaries are analyzed to discuss the nature and strength of intermolecular interactions in these mixtures.

  9. Insulin pumps: Beyond basal-bolus

    National Research Council Canada - National Science Library

    Millstein, Richard; Becerra, Nancy Mora; Shubrook, Jay H

    2015-01-01

    Insulin pumps are a major advance in diabetes management, making insulin dosing easier and more accurate and providing great flexibility, safety, and efficacy for people who need basal-bolus insulin therapy...

  10. Dual bolus intravenous contrast injection technique for multiregion paediatric body CT

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Karen E.; Mann, E.H.; Padfield, N.; Greco, L.; BenDavid, G. [The Hospital for Sick Children, Department of Diagnostic Imaging, Toronto (Canada); Alzahrani, A. [King Abdulaziz Medical City, PO Box 22490, Riyadh (Saudi Arabia)

    2015-04-01

    Optimal vascular and parenchymal enhancement for multi-region paediatric body computed tomography (CT) has many challenges. A variety of approaches are currently employed, associated with varying image quality and radiation dose implications. We present a dual bolus intravenous (DBI) contrast technique for single-acquisition imaging of the chest, abdomen and pelvis, with evaluation of multi-compartmental vascular enhancement. A DBI regime was designed for use with a programmable dual head pump injector. A larger initial bolus (two-thirds volume) is followed by a smaller bolus (one-third volume) before imaging the chest, abdomen and pelvis in a single acquisition, 45-65 seconds from the start of initial injection. Flow rates and second bolus timing were tailored to patient weight and contrast volume, using five weight categories. Multi-compartmental vascular opacification was graded and image quality was assessed in a cohort of 130 patients. The DBI technique resulted in concordant multi-compartmental (thoracic aortic, pulmonary arterial, abdominal aortic and portal venous) vascular enhancement. Early splenic parenchymal enhancement artefacts and alterations to renal enhancement were observed. We present a weight-stratified dual bolus intravenous contrast technique to improve image quality in paediatric multi-region body CT. (orig.)

  11. Density, viscosity, surface tension, and molar volume of propylene glycol + water mixtures from 293 to 323 K and correlations by the Jouyban–Acree model

    Directory of Open Access Journals (Sweden)

    Ibrahim S. Khattab

    2017-02-01

    Full Text Available Density, viscosity, surface tension and molar volume of propylene glycol + water mixtures at 293, 298, 303, 308, 313, 318, and 323 K are reported, compared with the available literature data and the Jouyban–Acree model was used for mathematical correlation of the data. The mean relative deviation (MRD was used as an error criterion and the MRD values for data correlation of density, viscosity, surface tension and molar volume at different investigated temperatures are 0.1 ± 0.1%, 7.6 ± 6.4%, 3.4 ± 3.7%, and 0.4 ± 0.4%, respectively. The corresponding MRDs for the predicted properties after training the model using the experimental data at 298 K are 0.1 ± 0.2%, 12.8 ± 9.3%, 4.7 ± 4.1% and 0.6 ± 0.5%, respectively for density, viscosity, surface tension, and molar volume data.

  12. Dispersion of a nanoliter bolus in microfluidic co-flow

    Science.gov (United States)

    Conway, A. J.; Saadi, W. M.; Sinatra, F. L.; Kowalski, G.; Larson, D.; Fiering, J.

    2014-03-01

    Microfluidic systems enable reactions and assays on the scale of nanoliters. However, at this scale non-uniformities in sample delivery become significant. To determine the fundamental minimum sample volume required for a particular device, a detailed understanding of mass transport is required. Co-flowing laminar streams are widely used in many devices, but typically only in the steady-state. Because establishing the co-flow steady-state consumes excess sample volume and time, there is a benefit to operating devices in the transient state, which predominates as the volume of the co-flow reactor decreases. Analysis of the co-flow transient has been neglected thus far. In this work we describe the fabrication of a pneumatically controlled microfluidic injector constructed to inject a discrete 50 nL bolus into one side of a two-stream co-flow reactor. Using dye for image analysis, injections were performed at a range of flow rates from 0.5-10 µL min-1, and for comparison we collected the co-flow steady-state data for this range. The results of the image analysis were also compared against theory and simulations for device validation. For evaluation, we established a metric that indicates how well the mass distribution in the bolus injection approximates steady-state co-flow. Using such analysis, transient-state injections can approximate steady-state conditions within pre-defined errors, allowing straightforward measurements to be performed with reduced reagent consumption.

  13. Evaluation of a Water-based Bolus Device for Radiotherapy to the Extremities in Kaposi's Sarcoma Patients

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Seung Kwon; Kim, Yong Bae; Lee, Ik Jae [Yonsei University College of Medicine, Seoul (Korea, Republic of)] (and others)

    2008-09-15

    We designed a water-based bolus device for radiation therapy in Kaposi's sarcoma. This study evaluated the usefulness of this new device and compared it with the currently used rice-based bolus. Materials and Methods: We fashioned a polystyrene box and cut a hole in order to insert patient's extremities while the patient was in the supine position. We used a vacuum-vinyl based polymer to reduce water leakage. Next, we eliminated air using a vacuum pump and a vacuum valve to reduce the air gap between the water and extremities in the vacuum-vinyl box. We performed CT scans to evaluate the density difference of the fabricated water-based bolus device when the device in which the rice-based bolus was placed directly, the rice-based bolus with polymer-vinyl packed rice, and the water were all put in. We analyzed the density change with the air gap volume using a planning system. In addition, we measured the homogeneity and dose in the low-extremities phantom, attached to six TLD, and wrapped film exposed in parallel-opposite fields with the LINAC under the same conditions as the set-up of the CT-simulator. Results: The density value of the rice-based bolus with the rice put in directly was 14% lower than that of the water-based bolus. Moreover, the value of the other experiments in the rice-based bolus with the polymer-vinyl packed rice showed an 18% reduction in density. The analysis of the EDR2 film revealed that the water-based bolus shows a more homogeneous dose plan, which was superior by 4.0-4.4% to the rice-base bolus. The mean TLD readings of the rice-based bolus, with the rice put directly into the polystyrene box had a 3.4% higher density value. Moreover, the density value in the case of the rice-based bolus with polymer-vinyl packed rice had a 4.3% higher reading compared to the water-based bolus. Conclusion: Our custom-made water-based bolus device increases the accuracy of the set-up by confirming the treatment field. It also improves the

  14. Sci—Thur AM: YIS - 07: Design and production of 3D printed bolus for electron radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Su, Shiqin [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia (Canada); Moran, Kathryn [Queen Elizabeth II Health Sciences Centre, Nova Scotia Cancer Centre, Halifax, Nova Scotia (Canada); Robar, James L. [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia (Canada); Department of Radiation Oncology, Dalhousie University, Halifax, Nova Scotia (Canada)

    2014-08-15

    This is a proof-of-concept study demonstrating the capacity for modulated electron radiation therapy (MERT) using 3D printed bolus. Previous reports have involved bolus design using an electron pencil beam model and fabrication using a milling machine. In this study, an in-house algorithm is presented that optimizes the dose distribution with regard to dose coverage, conformity and homogeneity within planning target volume (PTV). The algorithm uses calculated result of a commercial electron Monte Carlo dose calculation as input. Distances along ray lines from distal side of 90% isodose to distal surface of PTV are used to estimate the bolus thickness. Inhomogeneities within the calculation volume are accounted for using coefficient of equivalent thickness method. Several regional modulation operators are applied to improve dose coverage and uniformity. The process is iterated (usually twice) until an acceptable MERT plan is realized, and the final bolus is printed using solid polylactic acid. The method is evaluated with regular geometric phantoms, anthropomorphic phantoms and a clinical rhabdomyosarcoma pediatric case. In all cases the dose conformity is improved compared to that with uniform bolus. The printed boluses conform well to the surface of complex anthropomorphic phantoms. For the rhabdomyosarcoma patient, the MERT plan yields a reduction of mean dose by 38.2% in left kidney relative to uniform bolus. MERT using 3D printed bolus appears to be a practical, low cost approach to generating optimized bolus for electron therapy. The method is effective in improving conformity of prescription isodose surface and in sparing immediately adjacent normal tissues.

  15. Excess Volumes, Densities, Speeds of Sound, and Viscosities for the Binary Systems of 1-Octanol with Hexadecane and Squalane at (298.15, 303.15 and 308.15) K

    Science.gov (United States)

    Dubey, Gyan P.; Sharma, Monika

    2008-08-01

    Excess molar volumes, {V_m^E } , excess molar isentropic compressibilities, {K_{S,m}^E } , and deviations of the speeds of sound, u D, from their ideal values u id in an ideal mixture for binary mixtures of 1-octanol, C8H17OH, with hexadecane, C16H34, and squalane (2,6,10,15,19,23-hexamethyltetracosane), C30H62, at T = (298.15, 303.15, and 308.15) K and at atmospheric pressure were derived from experimental density, ρ, and speed-of-sound data, u. Viscosity measurements were also carried out for the same mixtures. The Prigogine-Flory-Patterson (PFP) theory has been applied to analyze {V_m^E} of these systems. Furthermore, the apparent molar volumes, {overline{{V}}_{\\varphi ,i}^0 } and apparent molar compressibility, {overline{{K}}_{\\varphi ,i}^{ 0} } of the components at infinite dilution have been calculated.

  16. Delivery confirmation of bolus electron conformal therapy combined with intensity modulated x-ray therapy

    Energy Technology Data Exchange (ETDEWEB)

    Kavanaugh, James A. [Department of Physics and Astronomy, Louisiana State University and Agricultural and Mechanical College, 202 Nicholson Hall, Tower Drive, Baton Rouge, Louisiana 70803-4001 (United States); Hogstrom, Kenneth R.; Fontenot, Jonas P.; Henkelmann, Gregory [Department of Physics and Astronomy, Louisiana State University and Agricultural and Mechanical College, 202 Nicholson Hall, Tower Drive, Baton Rouge, Louisiana 70803-4001 and Mary Bird Perkins Cancer Center, 4950 Essen Lane, Baton Rouge, Louisiana 70809 (United States); Chu, Connel; Carver, Robert A. [Mary Bird Perkins Cancer Center, 4950 Essen Lane, Baton Rouge, Louisiana 70809 (United States)

    2013-02-15

    Purpose: The purpose of this study was to demonstrate that a bolus electron conformal therapy (ECT) dose plan and a mixed beam plan, composed of an intensity modulated x-ray therapy (IMXT) dose plan optimized on top of the bolus ECT plan, can be accurately delivered. Methods: Calculated dose distributions were compared with measured dose distributions for parotid and chest wall (CW) bolus ECT and mixed beam plans, each simulated in a cylindrical polystyrene phantom that allowed film dose measurements. Bolus ECT plans were created for both parotid and CW PTVs (planning target volumes) using 20 and 16 MeV beams, respectively, whose 90% dose surface conformed to the PTV. Mixed beam plans consisted of an IMXT dose plan optimized on top of the bolus ECT dose plan. The bolus ECT, IMXT, and mixed beam dose distributions were measured using radiographic films in five transverse and one sagittal planes for a total of 36 measurement conditions. Corrections for film dose response, effects of edge-on photon irradiation, and effects of irregular phantom optical properties on the Cerenkov component of the film signal resulted in high precision measurements. Data set consistency was verified by agreement of depth dose at the intersections of the sagittal plane with the five measured transverse planes. For these same depth doses, results for the mixed beam plan agreed with the sum of the individual depth doses for the bolus ECT and IMXT plans. The six mean measured planar dose distributions were compared with those calculated by the treatment planning system for all modalities. Dose agreement was assessed using the 4% dose difference and 0.2 cm distance to agreement. Results: For the combined high-dose region and low-dose region, pass rates for the parotid and CW plans were 98.7% and 96.2%, respectively, for the bolus ECT plans and 97.9% and 97.4%, respectively, for the mixed beam plans. For the high-dose gradient region, pass rates for the parotid and CW plans were 93.1% and 94

  17. Aerosol bolus dispersion in acinar airways—influence of gravity and airway asymmetry

    Science.gov (United States)

    Ma, Baoshun

    2012-01-01

    The aerosol bolus technique can be used to estimate the degree of convective mixing in the lung; however, contributions of different lung compartments to measured dispersion cannot be differentiated unambiguously. To estimate dispersion in the distal lung, we studied the effect of gravity and airway asymmetry on the dispersion of 1 μm-diameter particle boluses in three-dimensional computational models of the lung periphery, ranging from a single alveolar sac to four-generation (g4) structures of bifurcating airways that deformed homogeneously during breathing. Boluses were introduced at the beginning of a 2-s inhalation, immediately followed by a 3-s exhalation. Dispersion was estimated by the half-width of the exhaled bolus. Dispersion was significantly affected by the spatial orientation of the models in normal gravity and was less in zero gravity than in normal gravity. Dispersion was strongly correlated with model volume in both normal and zero gravity. Predicted pulmonary dispersion based on a symmetric g4 acinar model was 391 ml and 238 ml under normal and zero gravity, respectively. These results accounted for a significant amount of dispersion measured experimentally. In zero gravity, predicted dispersion in a highly asymmetric model accounted for ∼20% of that obtained in a symmetric model with comparable volume and number of alveolated branches, whereas normal gravity dispersions were comparable in both models. These results suggest that gravitational sedimentation and not geometrical asymmetry is the dominant factor in aerosol dispersion in the lung periphery. PMID:22678957

  18. Comparative evaluation of aqueous humor viscosity.

    Science.gov (United States)

    Davis, Kyshia; Carter, Renee; Tully, Thomas; Negulescu, Ioan; Storey, Eric

    2015-01-01

    To evaluate aqueous humor viscosity in the raptor, dog, cat, and horse, with a primary focus on the barred owl (Strix varia). Twenty-six raptors, ten dogs, three cats, and one horse. Animals were euthanized for reasons unrelated to this study. Immediately, after horizontal and vertical corneal dimensions were measured, and anterior chamber paracentesis was performed to quantify anterior chamber volume and obtain aqueous humor samples for viscosity analysis. Dynamic aqueous humor viscosity was measured using a dynamic shear rheometer (AR 1000 TA Instruments, New Castle, DE, USA) at 20 °C. Statistical analysis included descriptive statistics, unpaired t-tests, and Tukey's test to evaluate the mean ± standard deviation for corneal diameter, anterior chamber volume, and aqueous humor viscosity amongst groups and calculation of Spearman's coefficient for correlation analyses. The mean aqueous humor viscosity in the barred owl was 14.1 centipoise (cP) ± 9, cat 4.4 cP ± 0.2, and dog 2.9 cP ± 1.3. The aqueous humor viscosity for the horse was 1 cP. Of the animals evaluated in this study, the raptor aqueous humor was the most viscous. The aqueous humor of the barred owl is significantly more viscous than the dog (P humor viscosity of the raptor, dog, cat, and horse can be successfully determined using a dynamic shear rheometer. © 2014 American College of Veterinary Ophthalmologists.

  19. 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.

  20. Efficacy of bolus intravenous iron treatment in peritoneal dialysis patients

    Directory of Open Access Journals (Sweden)

    Jovanović Nataša

    2005-01-01

    Full Text Available Introduction. Normocytic, normochromic anemia is one of the first signs of chronic renal failure and it is common in patients on chronic dialysis treatment. It causes decrease in oxygen supply to tissues, increases cardiac minute volume, causes left ventricular hyperthrophy, cardiac insufficiency, disorders related to cognitive functions and immune response, and increases morbidity and mortality rates. The leading cause of anemia in patients on chronic peritoneal dialysis (PD is iron depletion and most patients on PD need oral or parenteral iron supplementation. The aim of this study was to evaluate our first experience with bolus intravenous ferrogluconate therapy in patients on chronic peritoneal dialysis at the Nephrology Clinic of the Clinical Center of Serbia (CCS. Material and Methods. We examined 11 patients, 7 males and 4 females, mean-age 49 years (range 31 to 68 years on chronic PD. All patients received blood transfusions, oral or intramuscular iron supplementation before 465 to 665 mg ferrogluconate therapy was given in 500 ml. saline intravenous infusion; 5 of them were on erythropoietin therapy and 2 of them started with EPO therapy after the ferrogluconate therapy. Results. The blood count improved during the first 3 months after application of bolus intravenous iron therapy (ferrogluconate; erythropoietin dose was not increased during the follow-up. Some patients suffered from side effects during infusion and 6 patients received the complete treatment. Discussion. Blood count improves in a number of patients affected by end-stage renal disease during the first months on continuous ambulatory peritoneal dialysis (CAPD treatment. But a large number of patients on chronic CAPD treatment are iron-depleted and they require oral or parenteral substitution. Side effects and complications of intravenous iron therapy were not severe and only one patient suffered from allergic manifestations. Ferremia and blood count improved in patients

  1. Excess Molar Volume, Viscosity and Heat Capacity for the Binary Mixture of p-Xylene and Acetic Acid at Different Temperatures%对二甲苯和醋酸二元液体混合物在不同温度下的超额摩尔体积、粘度和热容

    Institute of Scientific and Technical Information of China (English)

    杨长生; 马沛生; 唐多强; 尹秋响; 赵长伟

    2002-01-01

    Experimental densities, viscosities and heat capacities at different temperatures were presented overthe entire range of mole fraction for the binary mixture of p-xylene and acetic acid. Density values were used in thedetermination of excess molar volumes, VE. At the same time, the excess viscosity and excess molar heat capacitieswere calculated. The values of VE, ηE and cpE were fitted to the Redlich-Kister equation. Good agreements wereobserved. The excess molar volumes are positive with a large maximum value located in the central concentrationrange. The excess viscosity has an opposite trend to the excess molar volume VE. ηE values are negative over theentire range of the mixture. The cure of dependence of cEp on concentration has a special shape. The molecularinteraction between p-xylene and acetic acid is discussed.

  2. How influential is the duration of contrast material bolus injection in perfusion CT? evaluation in a swine model.

    Science.gov (United States)

    Kandel, Sonja M; Meyer, Henning; Boehnert, Markus; Hoppel, Bernice; Paul, Narinder Singh; Rogalla, Patrik

    2014-01-01

    To analyze the effect of the duration of contrast material bolus injection on perfusion values in a swine model by using the maximum slope method. This study was approved by the institutional animal care committee. Twenty pigs (weight range, 63-77 kg) underwent dynamic volume computed tomography (CT) of the kidneys during suspended respiration. Before the CT examination, a miniature cuff-shaped ultrasonographic flow probe encircling the right renal artery was surgically implanted in each pig to obtain true perfusion values. Two sequential perfusion CT series were performed in 30 seconds, each comprising 30 volumes with identical parameters (100 kV, 200 mAs, 0.5 sec rotation time). The duration of contrast material bolus (0.5 mL/kg of body weight) was 3.8 seconds in the first series (short bolus series) and 11.5 seconds in the second series (long bolus series), and the injection flow rate was adapted accordingly. In each pig, cortical kidney volume was determined by using the volume with the highest cortical enhancement. CT perfusion values were calculated for both series by using the maximum slope method and were statistically compared and correlated with the true perfusion values from the flow probe by using linear regression analysis. Mean true perfusion and CT perfusion values (in minutes(-1)) for the short bolus series were 1.95 and 2.03, respectively (P = .22), and for the long bolus series, they were 2.02 and 1.92, respectively (P = .12). CT perfusion showed very good correlation with true perfusion in both the short (slope, 1.01; 95% confidence interval: 0.91, 1.11) and long (slope, 0.92; 95% confidence interval: 0.78, 1.04) series. On the basis of the regression analysis, CT perfusion values in the short bolus series were overestimated by 1% and those in the long bolus series were underestimated by 8%. Duration of contrast material bolus injection does not influence CT perfusion values substantially. The longer, clinically preferred intravenous injection

  3. Accuracy of pencil-beam redefinition algorithm dose calculations in patient-like cylindrical phantoms for bolus electron conformal therapy

    Energy Technology Data Exchange (ETDEWEB)

    Carver, Robert L.; Hogstrom, Kenneth R. [Mary Bird Perkins Cancer Center, 4950 Essen Lane, Baton Rouge, Louisiana 70809 (United States); Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Chu, Connel; Fields, Robert S. [Mary Bird Perkins Cancer Center, 4950 Essen Lane, Baton Rouge, Louisiana 70809 (United States); Sprunger, Conrad P. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803 (United States)

    2013-07-15

    Purpose: The purpose of this study was to document the improved accuracy of the pencil beam redefinition algorithm (PBRA) compared to the pencil beam algorithm (PBA) for bolus electron conformal therapy using cylindrical patient phantoms based on patient computed tomography (CT) scans of retromolar trigone and nose cancer.Methods: PBRA and PBA electron dose calculations were compared with measured dose in retromolar trigone and nose phantoms both with and without bolus. For the bolus treatment plans, a radiation oncologist outlined a planning target volume (PTV) on the central axis slice of the CT scan for each phantom. A bolus was designed using the planning.decimal{sup Registered-Sign} (p.d) software (.decimal, Inc., Sanford, FL) to conform the 90% dose line to the distal surface of the PTV. Dose measurements were taken with thermoluminescent dosimeters placed into predrilled holes. The Pinnacle{sup 3} (Philips Healthcare, Andover, MD) treatment planning system was used to calculate PBA dose distributions. The PBRA dose distributions were calculated with an in-house C++ program. In order to accurately account for the phantom materials a table correlating CT number to relative electron stopping and scattering powers was compiled and used for both PBA and PBRA dose calculations. Accuracy was determined by comparing differences in measured and calculated dose, as well as distance to agreement for each measurement point.Results: The measured doses had an average precision of 0.9%. For the retromolar trigone phantom, the PBRA dose calculations had an average {+-}1{sigma} dose difference (calculated - measured) of -0.65%{+-} 1.62% without the bolus and -0.20%{+-} 1.54% with the bolus. The PBA dose calculation had an average dose difference of 0.19%{+-} 3.27% without the bolus and -0.05%{+-} 3.14% with the bolus. For the nose phantom, the PBRA dose calculations had an average dose difference of 0.50%{+-} 3.06% without bolus and -0.18%{+-} 1.22% with the bolus. The PBA

  4. 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.

  5. Intravenous Contrast Material Administration at High-pitch Dual-source CT Coronary Angiography: Bolus-tracking Technique with Shortened Time of Respiratory Instruction Versus Test Bolus Technique

    Institute of Scientific and Technical Information of China (English)

    Kai Sun; Guo-rong Liu; Yue-chun Li; Rui-juan Han; Li-fang Cui; Li-jun Ma; Li-gang Li; Chang-yong Li

    2012-01-01

    Objective To investigate the feasibility of acquiring the similar homogeneous enhancement using bolus-tracking techniques with shortened respiratory time in prospectively electrocardiogram-gated high-pitch spiral acquisition mode (Flash mode) coronary computed tomography angiography (CCTA) compared with test bolus technique.Methods One hundred and eighty-four consecutive patients with mean heart rate ≤65 beats per minute undergoing CCTA were prospectively included in this study.The patients were randomly divided into two groups.Patients in the group A (n=92) instructed to shorten respiratory time received CCTA using bolus-tracking technique with high-pitch spiral acquisition mode (Flash mode),while those in the group B (n=92) underwent CCTA with test bolus technique.The attenuation in the ascending aorta,image noise,contrast-to-noise ratio and radiation doses of the two groups were assessed.Results There were no significant differences in the mean attenuation values in the ascending aorta (483.18±59.07 HU vs.498.7±83.51 HU,P=0.183),image noise (21.4±4.5 HU vs.20.9±4.3 HU,P=0.414),contrast-to-noise ratio (12.1±4.2 vs.13.8±5.1,P=0.31) between the groups A and B.There were no significant differences in the radiation dose of dynamic monitoring scans (0.056±0.026 mSv vs.0.062±0.018 mSv,P=0.068) and radiation dose of angiography (0.94±0.07 mSv vs.0.96±0.15 mSv,P=0.926) between the two groups,while 15 mL less contrast material volume was administered in the group A than the group B.Conclusion Bolus-tracking technique with shortened time of respiratory in Flash mode of dual-source CT yields the similar homogeneous enhancement with less contrast material in comparison to the test bolus technique.

  6. The comparison of bolus tracking and test bolus techniques for computed tomography thoracic angiography in healthy beagles

    Directory of Open Access Journals (Sweden)

    Nicolette Cassel

    2013-02-01

    Full Text Available Computed tomography thoracic angiography studies were performed on five adult beagles using the bolus tracking (BT technique and the test bolus (TB technique, which were performed at least two weeks apart. For the BT technique, 2 mL/kg of 300 mgI/mL iodinated contrast agent was injected intravenously. Scans were initiated when the contrast in the aorta reached 150 Hounsfield units (HU. For the TB technique, the dogs received a test dose of 15% of 2 mL/kg of 300 mgI/mL iodinated contrast agent, followed by a series of low dose sequential scans. The full dose of the contrast agent was then administered and the scans were conducted at optimal times as identified from time attenuation curves. Mean attenuation in HU was measured in the aorta (Ao and right caudal pulmonary artery (rCPA. Additional observations included the study duration, milliAmpere (mA, computed tomography dose index volume (CTDI[vol] and dose length product (DLP. The attenuation in the Ao (BT = 660 52 HU ± 138 49 HU, TB = 469 82 HU ± 199 52 HU, p = 0.13 and in the rCPA (BT = 606 34 HU ± 143 37 HU, TB = 413 72 HU ± 174.99 HU, p = 0.28 did not differ significantly between the two techniques. The BT technique was conducted in a significantly shorter time period than the TB technique (p = 0.03. The mean mA for the BT technique was significantly lower than the TB technique (p = 0.03, as was the mean CTDI(vol (p = 0.001. The mean DLP did not differ significantly between the two techniques (p = 0.17. No preference was given to either technique when evaluating the Ao or rCPA but the BT technique was shown to be shorter in duration and resulted in less DLP than the TB technique.

  7. The effect of the volume fraction and viscosity on the compression and tension behavior of the cobalt-ferrite magneto-rheological fluids

    Directory of Open Access Journals (Sweden)

    H. Shokrollahi

    2016-03-01

    Full Text Available The purpose of this work is to investigate the effects of the volume fraction and bimodal distribution of solid particles on the compression and tension behavior of the Co-ferrite-based magneto-rheological fluids (MRFs containing silicon oil as a carrier. Hence, Co-ferrite particles (CoFe2O4 with two various sizes were synthesized by the chemical co-precipitation method and mixed so as to prepare the bimodal MRF. The X-Ray Diffraction (XRD analysis, Fourier Transform Infrared Spectroscopy (FTIR, Laser Particle Size Analysis (LPSA and Vibrating Sample Magnetometer (VSM were conducted to examine the structural and magnetic properties, respectively. The results indicated that the increase of the volume fraction has a direct increasing influence on the values of the compression and tension strengths of fluids. In addition, the compression and tension strengths of the mixed MRF sample (1.274 and 0.647 MPa containing 60 and 550 nm samples were higher than those of the MRF sample with the same volume fraction and uniform particle size of 550 nm.

  8. A bolus/infusion paradigm for the novel NMDA receptor SPET tracer [{sup 123}i]CNS 1261

    Energy Technology Data Exchange (ETDEWEB)

    Bressan, Rodrigo A; Erlandsson, Kjell E-mail: k.erlandsson@nucmed.ucl.ac.uk; Mulligan, Rachel S; Gunn, Roger N.; Cunningham, Vincent J.; Owens, Jonathan; Cullum, Ian D.; Ell, Peter J.; Pilowsky, Lyn S

    2004-02-01

    We have previously performed quantitative kinetic modeling of [{sup 123}I]CNS 1261, a new SPET ligand for the MK801 intrachannel site of the NMDA receptor. We now report a bolus-infusion protocol, which eliminates the need for arterial blood sampling. Dynamic SPET scanning and venous blood sampling were performed in 7 healthy volunteers. Good agreement was obtained between kinetic and equilibrium analysis. SPET scanning with a bolus-infusion protocol is a valid method to estimate the total volume of distribution for [{sup 123}I]CNS 1261 in clinical populations.

  9. Measurement and Correlation on Viscosity and Apparent Molar Volume of Ternary System for L-ascorbic Acid in Aqueous D-Glucose and Sucrose Solutions%L-抗坏血酸在葡萄糖和蔗糖溶液中的黏度及其热力学性质的研究

    Institute of Scientific and Technical Information of China (English)

    赵长伟; 马沛生

    2003-01-01

    Viscosities and densities at several temperatures from 293.15 K to 313.15 K are reported for L-ascorbic acid in aqueous glucose and sucrose solutions at different concentrations. The parameters of density, viscosity coefficient B and partial molar volume are calculated by regression. The experimental results show that densities and viscosities decrease as temperature increases at the same solute and solvent (glucose and sucrose aqueous solution) concentrations, and increase with concentration of glucose and sucrose at the same solute concentration and temperature. B increases with concentration of glucose and sucrose and temperature. L-ascorbic acid is structure-breaker or structure-making for the glucose and sucrose aqueous solutions. Furthermore, the solute-solvent interactions in ternary systems of water-glucose-electrolyte and water-sucrose-electrolyte are discussed.

  10. 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.

  11. On bolus for megavoltage photon and electron radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Vyas, Vedang [University of Waterloo, Waterloo, Ontario (Canada); Grand River Regional Cancer Centre, Kitchener, Ontario (Canada); Palmer, Lisa; Mudge, Ray [Grand River Regional Cancer Centre, Kitchener, Ontario (Canada); Jiang, Runqing [University of Waterloo, Waterloo, Ontario (Canada); Grand River Regional Cancer Centre, Kitchener, Ontario (Canada); Fleck, Andre [Grand River Regional Cancer Centre, Kitchener, Ontario (Canada); Schaly, Bryan [London Regional Cancer Program, London, Ontario (Canada); Osei, Ernest [University of Waterloo, Waterloo, Ontario (Canada); Grand River Regional Cancer Centre, Kitchener, Ontario (Canada); Charland, Paule, E-mail: paule.charland@grhosp.on.ca [Grand River Regional Cancer Centre, Kitchener, Ontario (Canada)

    2013-10-01

    Frequently, in radiation therapy one must treat superficial lesions on cancer patients; these are at or adjacent to the skin. Megavoltage photon radiotherapy penetrates through the skin to irradiate deep-seated tumors, with skin-sparing property. Hence, to treat superficial lesions, one must use a layer of scattering material to feign as the skin surface. Although megavoltage electron beams are used for superficial treatments, one occasionally needs to enhance the dose near the surface. Such is the function of a “bolus,” a natural or synthetically developed material that acts as a layer of tissue to provide a more effective treatment to the superficial lesions. Other uses of boluses are to correct for varying surface contours and to add scattering material around the patient's surface. Materials used as bolus vary from simple water to metal and include various mixtures and compounds. Even with the modernization of the technology for external-beam therapy and the emergence of various commercial boluses, the preparation and utilization of a bolus in clinical radiotherapy remains an art. Considering the varying experiences and practices, this paper briefly summarizes available boluses that have been proposed and are employed in clinical radiotherapy. Although this review is not exhaustive, it provides some initial guidance and answers questions that may arise in clinical practice.

  12. 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.

  13. 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.

  14. Total meltwater volume since the Last Glacial Maximum and viscosity structure of Earth's mantle inferred from relative sea level changes at Barbados and Bonaparte Gulf and GIA-induced J˙2

    Science.gov (United States)

    Nakada, Masao; Okuno, Jun'ichi; Yokoyama, Yusuke

    2016-02-01

    Inference of globally averaged eustatic sea level (ESL) rise since the Last Glacial Maximum (LGM) highly depends on the interpretation of relative sea level (RSL) observations at Barbados and Bonaparte Gulf, Australia, which are sensitive to the viscosity structure of Earth's mantle. Here we examine the RSL changes at the LGM for Barbados and Bonaparte Gulf ({{RSL}}_{{L}}^{{{Bar}}} and {{RSL}}_{{L}}^{{{Bon}}}), differential RSL for both sites (Δ {{RSL}}_{{L}}^{{{Bar}},{{Bon}}}) and rate of change of degree-two harmonics of Earth's geopotential due to glacial isostatic adjustment (GIA) process (GIA-induced J˙2) to infer the ESL component and viscosity structure of Earth's mantle. Differential RSL, Δ {{RSL}}_{{L}}^{{{Bar}},{{Bon}}} and GIA-induced J˙2 are dominantly sensitive to the lower-mantle viscosity, and nearly insensitive to the upper-mantle rheological structure and GIA ice models with an ESL component of about (120-130) m. The comparison between the predicted and observationally derived Δ {{RSL}}_{{L}}^{{{Bar}},{{Bon}}} indicates the lower-mantle viscosity higher than ˜2 × 1022 Pa s, and the observationally derived GIA-induced J˙2 of -(6.0-6.5) × 10-11 yr-1 indicates two permissible solutions for the lower mantle, ˜1022 and (5-10) × 1022 Pa s. That is, the effective lower-mantle viscosity inferred from these two observational constraints is (5-10) × 1022 Pa s. The LGM RSL changes at both sites, {{RSL}}_{{L}}^{{{Bar}}} and {{RSL}}_{{L}}^{{{Bon}}}, are also sensitive to the ESL component and upper-mantle viscosity as well as the lower-mantle viscosity. The permissible upper-mantle viscosity increases with decreasing ESL component due to the sensitivity of the LGM sea level at Bonaparte Gulf ({{RSL}}_{{L}}^{{{Bon}}}) to the upper-mantle viscosity, and inferred upper-mantle viscosity for adopted lithospheric thicknesses of 65 and 100 km is (1-3) × 1020 Pa s for ESL˜130 m and (4-10) × 1020 Pa s for ESL˜125 m. The former solution of (1-3) × 1020

  15. Field dependence of magnetic viscosity of CoCrTa in-plane media

    NARCIS (Netherlands)

    Phan le kim, P.L.K.; Lodder, J.C.; Popma, T.J.A.

    1999-01-01

    In this paper we will present a study of magnetic viscosity as a function of applied field of CoCrTa/Cr in-plane media. The viscosity versus applied field curves (viscosity curves) of the samples exhibit a sharp peak at remanence coercivity (Hcr). Their activation volume was found to be close to the

  16. Dopamine D(2) receptor quantification in extrastriatal brain regions using [(123)I]epidepride with bolus/infusion

    DEFF Research Database (Denmark)

    Pinborg, L H; Videbaek, C; Knudsen, G M

    2000-01-01

    The iodinated benzamide epidepride, which shows a picomolar affinity binding to dopamine D(2) receptors, has been designed for in vivo studies using SPECT. The aim of the present study was to apply a steady-state condition by the bolus/infusion approach with [(123)I]epidepride for the quantificat......The iodinated benzamide epidepride, which shows a picomolar affinity binding to dopamine D(2) receptors, has been designed for in vivo studies using SPECT. The aim of the present study was to apply a steady-state condition by the bolus/infusion approach with [(123)I......]epidepride for the quantification of striatal and extrastriatal dopamine D(2) receptors in humans. In this way the distribution volume of the tracer can be determined from a single SPECT image and one blood sample. Based on bolus experiments, an algorithm using conventional convolution arguments for prediction of the outcome...... has a unique signal-to-noise ratio compared to [(123)I]IBZM but present difficulties for steady-state measurements of striatal regions. The bolus/infusion approach is particularly feasible for quantification of the binding potential in extrastriatal regions....

  17. Understanding bolus insulin dose timing: the characteristics and experiences of people with diabetes who take bolus insulin.

    Science.gov (United States)

    Tamborlane, William V; Pfeiffer, Kathryn M; Brod, Meryl; Nikolajsen, Annie; Sandberg, Anna; Peters, Anne L; Van Name, Michelle

    2017-04-01

    Despite the increased popularity of newer, fast-acting bolus insulin treatment options that allow for more flexibility in the timing of bolus insulin dosing in recent years, relatively little is known about people with diabetes who administer bolus insulin at differing times in relation to their meals. The purpose of this study was to investigate bolus insulin dose timing in relation to meals among people with type 1 (T1D) and type 2 (T2D) diabetes, as well as to better understand the characteristics and experiences of people who bolus dose at differing times. A web-based survey of adults with T1D and T2D treated with bolus insulin therapy in Germany, the UK, and USA was conducted. A total of 906 respondents completed the survey (39% T1D; 61% T2D). A majority of respondents reported bolus dosing before meals in the previous week (57.0%), followed by after meals (18.9%), with meals (12.7%), and at varying times (11.5%). Compared to respondents who dosed with or after meals, those who dosed before meals were significantly less likely to experience hypoglycemia (before, 55.7%; with, 72.8%; after, 68.7%; p insulin with or after meals. Key limitations of all self-report surveys include potential bias in responses and generalizability of findings. However, the study was designed to help mitigate these limitations. The findings have implications for clinicians and suggest opportunities for improving diabetes education and care.

  18. A customized bolus produced using a 3-dimensional printer for radiotherapy.

    Science.gov (United States)

    Kim, Shin-Wook; Shin, Hun-Joo; Kay, Chul Seung; Son, Seok Hyun

    2014-01-01

    Boluses are used in high-energy radiotherapy in order to overcome the skin sparing effect. In practice though, commonly used flat boluses fail to make a perfect contact with the irregular surface of the patient's skin, resulting in air gaps. Hence, we fabricated a customized bolus using a 3-dimensional (3D) printer and evaluated its feasibility for radiotherapy. We designed two kinds of bolus for production on a 3D printer, one of which was the 3D printed flat bolus for the Blue water phantom and the other was a 3D printed customized bolus for the RANDO phantom. The 3D printed flat bolus was fabricated to verify its physical quality. The resulting 3D printed flat bolus was evaluated by assessing dosimetric parameters such as D1.5 cm, D5 cm, and D10 cm. The 3D printed customized bolus was then fabricated, and its quality and clinical feasibility were evaluated by visual inspection and by assessing dosimetric parameters such as Dmax, Dmin, Dmean, D90%, and V90%. The dosimetric parameters of the resulting 3D printed flat bolus showed that it was a useful dose escalating material, equivalent to a commercially available flat bolus. Analysis of the dosimetric parameters of the 3D printed customized bolus demonstrated that it is provided good dose escalation and good contact with the irregular surface of the RANDO phantom. A customized bolus produced using a 3D printer could potentially replace commercially available flat boluses.

  19. 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.

  20. Vasopressin Bolus Protocol Compared to Desmopressin (DDAVP for Managing Acute, Postoperative Central Diabetes Insipidus and Hypovolemic Shock

    Directory of Open Access Journals (Sweden)

    Anukrati Shukla

    2017-01-01

    Full Text Available Introduction. Management of postoperative central diabetes insipidus (DI can be challenging from changes in volume status and serum sodium levels. We report a case successfully using a dilute vasopressin bolus protocol in managing hypovolemic shock in acute, postoperative, central DI. Case Report. Patient presented after bifrontal decompressive craniotomy for severe traumatic brain injury. He developed increased urine output resulting in hypovolemia and hypernatremia. He was resuscitated with intravenous fluids including a dilute vasopressin bolus protocol. This protocol consisted of 1 unit of vasopressin in 1 liter of 0.45% normal saline. This protocol was given in boluses based on the formula: urine output minus one hundred. Initial serum sodium was 148 mmol/L, and one-hour urine output was 1 liter. After 48 hours, he transitioned to 1-desamino-8-D-arginine vasopressin (DDAVP. Pre-DDAVP serum sodium was 149 mmol/L and one-hour urine output 320 cc. Comparing the bolus protocol to the DDAVP protocol, the average sodium was 143.8 ± 3.2 and 149.6 ± 3.2 mmol/L (p=0.0001, average urine output was 433.2 ± 354.4 and 422.3 ± 276.0 cc/hr (p=0.90, and average specific gravity was 1.019 ± 0.009 and 1.016 ± 0.01 (p=0.42, respectively. Conclusion. A protocol using dilute vasopressin bolus can be an alternative for managing acute, central DI postoperatively, particularly in setting of hypovolemic shock resulting in a consistent control of serum sodium.

  1. 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.

  2. 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.

  3. 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).

  4. 21 CFR 520.1197 - Ivermectin sustained-release bolus.

    Science.gov (United States)

    2010-04-01

    ... withdrawal time has not been established, do not use in female dairy cattle of breeding age. Do not slaughter cattle within 180 days of treatment. Consult your veterinarian for assistance in the diagnosis, treatment..., and ticks Amblyomma americanum. (3) Limitations. The bolus was specifically designed for use in...

  5. Virtual bolus for total body irradiation treated with helical tomotherapy.

    Science.gov (United States)

    Moliner, Gilles; Izar, Françoise; Ferrand, Régis; Bardies, Manuel; Ken, Soléakhéna; Simon, Luc

    2015-11-08

    Intensity-modulated radiation therapy (IMRT) for total body irradiation (TBI) is practiced in several centers using the TomoTherapy System. In this context the planning target volume (PTV) is the entire body including the skin. A safety margin in the air surrounding the body should be added to take into account setup errors. But using inverse planning, over-fluence peak could be generated in the skin region to insure dose homogeneity. This work proposes to study the performance of the use of a virtual bolus (VB). A VB is a material placed on the skin surface during planning, but absent for the real treatment. The optimal VB that compensates large setup errors without introducing a high-dose increase or hot spots for small setup errors was determined. For two cylindrical phantoms, 20VBs with different densities, thicknesses or designs were tested. Dose coverage of the PTV (V95%) in the presence of simulated setup errors was computed to assess the VB performance. A measure of the dose increase in the phantom center due to the absence of the VB during treatment was also achieved. Finally, the fluence peak at the phantom edge was measured in complete buildup conditions using a large phantom and a detector matrix. Using these VBs, simulated setup errors were compensated to a minimum value of 2.6 and 2.1 cm for small and large phantom, respectively (and only 1.2 and 1.7 cm with no VB). An optimal double-layer VB was found with a density of 0.4 kg.m(-3) and a total thickness of 8mm; an inner layer of 5 mm was declared as the target for the treatment planning system and an additional layer of 3 mm was added to avoid the over-fluence peak. Using this VB, setup errors were compensated up to 2.9 cm. The dose increase was measured to be only +1.5% at the phantom center and over-fluence peak was strongly decreased.

  6. 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.

  7. Comparison and evaluation between 3D-bolus and step-bolus, the assistive radiotherapy devices for the patients who had undergone modified radical mastectomy surgery

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Won Seok; Park, Kwang Woo; Shin, Dong Bong; Kim, Jong Dae; Kim, Sei Joon; Ha, Jin Sook; Jeon, Mi Jin; Cho, Yoojin; Jung, Inho [Dept. of Radiation Oncology, Gangnam Severance Hospital, Seoul, (Korea, Republic of)

    2016-06-15

    This study aimed to compare and evaluate between the efficiency of two respective devices, 3D-bolus and step-bolus when the devices were used for the treatment of patients whose chest walls were required to undergo the electron beam therapy after the surgical procedure of modified radical mastectomy, MRM. The treatment plan of reverse hockey stick method, using the photon beam and electron beam, had been set for six breast cancer patients and these 6 breast cancer patients were selected to be the subjects for this study. The prescribed dose of electron beam for anterior chest wall was set to be 180 cGy per treatment and both the 3D-bolus, produced using 3D printer(CubeX, 3D systems, USA) and the self-made conventional step-bolus were used respectively. The surface dose under 3D-bolus and step-bolus was measured at 5 measurement spots of iso-center, lateral, medial, superior and inferior point, using GAFCHROMIC EBT3 film (International specialty products, USA) and the measured value of dose at 5 spots was compared and analyzed. Also the respective treatment plan was devised, considering the adoption of 3D-bolus and stepbolus and the separate treatment results were compared to each other. The average surface dose was 179.17 cGy when the device of 3D-bolus was adopted and 172.02 cGy when step-bolus was adopted. The average error rate against the prescribed dose of 180 cGy was -(minus) 0.47% when the device of 3D-bolus was adopted and it was -(minus) 4.43% when step-bolus was adopted. It was turned out that the maximum error rate at the point of iso-center was 2.69%, in case of 3D-bolus adoption and it was 5,54% in case of step-bolus adoption. The maximum discrepancy in terms of treatment accuracy was revealed to be about 6% when step-bolus was adopted and to be about 3% when 3D-bolus was adopted. The difference in average target dose on chest wall between 3D-bolus treatment plan and step-bolus treatment plan was shown to be insignificant as the difference was only 0

  8. SU-C-213-03: Custom 3D Printed Boluses for Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, B; Yang, M; Yan, Y; Rahimi, A; Chopra, R; Jiang, S [UT Southwestern Medical Center, Dallas, TX (United States)

    2015-06-15

    Purpose: To develop a clinical workflow and to commission the process of creating custom 3d printed boluses for radiation therapy. Methods: We designed a workflow to create custom boluses using a commercial 3D printer. Contours of several patients were deformably mapped to phantoms where the test bolus contours were designed. Treatment plans were created on the phantoms following our institutional planning guideline. The DICOM file of the bolus contours were then converted to stereoLithography (stl) file for the 3d printer. The boluses were printed on a commercial 3D printer using polylactic acid (PLA) material. Custom printing parameters were optimized in order to meet the requirement of bolus composition. The workflow was tested on multiple anatomical sites such as skull, nose and chest wall. The size of boluses varies from 6×9cm2 to 12×25cm2. To commission the process, basic CT and dose properties of the printing materials were measured in photon and electron beams and compared against water and soft superflab bolus. Phantoms were then scanned to confirm the placement of custom boluses. Finally dose distributions with rescanned CTs were compared with those computer-generated boluses. Results: The relative electron density(1.08±0.006) of the printed boluses resemble those of liquid tap water(1.04±0.004). The dosimetric properties resemble those of liquid tap water(1.04±0.004). The dosimetric properties were measured at dmax with an ion chamber in electron and photon open beams. Compared with solid water and soft bolus, the output difference was within 1% for the 3D printer material. The printed boluses fit well to the phantom surfaces on CT scans. The dose distribution and DVH based on the printed boluses match well with those based on TPS generated boluses. Conclusion: 3d printing provides a cost effective and convenient solution for patient-specific boluses in radiation therapy.

  9. SU-E-T-437: Dosimetric Assessment of Brass Mesh Bolus for Postmastectomy Chest Wall Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Manger, R; Paxton, A; Cervino, L [University of California, San Diego, La Jolla, CA (United States)

    2014-06-01

    Purpose: It has been suggested that the use of a brass mesh bolus for chest wall irradiation sufficiently increases surface dose while having little effect on the dose at depth. This work quantified the increase in surface dose when using a brass mesh bolus in postmastectomy chest wall radiotherapy compared to tissue-equivalent bolus and assessed its effect on dose at depth. Methods: Percent depth doses with brass bolus, 5mm tissue-equivalent bolus, and no bolus were determined for a 6 MV photon beam in a solid water phantom using a parallel plate ionization chamber. Gafchromic film was used to determine the surface dose for the same three experimental setups. For comparison to a realistic treatment setup, gafchromic film and OSLDs were used to determine the surface dose over the irradiated area of a 6 MV chest wall plan with tangential beams delivered to a heterogeneous thorax phantom. The plan was generated using a CT of the phantom and delivered using brass mesh bolus, 5mm tissue-equivalent bolus, and no bolus. Results: For the en face beam, the central surface dose increased to 90% of maximum with the tissue-equivalent bolus, but to only 62% of maximum with the brass mesh. Using tangential beams on the thorax phantom, the surface dose increased from 40–72% to 75–110% of prescribed dose, with the brass mesh, and to 85–109% with the tissue-equivalent bolus. At depths beyond dmax in the plastic water phantom, the dose with and without brass mesh bolus differed by less than 0.5%. Conclusion: A brass mesh may be considered as a substitute for tissue-equivalent bolus to increase the superficial dose of 6 MV chest wall tangent plans. The brass mesh does not significantly change the dose at depth, so a non-bolus plan could be used for bolus and non-bolus treatments.

  10. Viscosity of the earth's core.

    Science.gov (United States)

    Gans, R. F.

    1972-01-01

    Calculation of the viscosity of the core at the boundary of the inner and outer core. It is assumed that this boundary is a melting transition and the viscosity limits of the Andrade (1934,1952) hypothesis (3.7 to 18.5 cp) are adopted. The corresponding kinematic viscosities are such that the precessional system explored by Malkus (1968) would be unstable. Whether it would be sufficiently unstable to overcome a severely subadiabatic temperature gradient cannot be determined.

  11. Experimental determination of viscosity of water based magnetite nanofluid for application in heating and cooling systems

    Energy Technology Data Exchange (ETDEWEB)

    Toghraie, Davood; Alempour, Seyed Mohammadbagher [Department of Mechanical Engineering, Khomeinishahr Branch, Islamic Azad University, Isfahan (Iran, Islamic Republic of); Afrand, Masoud, E-mail: masoud.afrand@pmc.iaun.ac.ir [Department of Mechanical Engineering, Najafabad Branch, Islamic Azad University, Najafabad (Iran, Islamic Republic of)

    2016-11-01

    In this paper, experimental determination of dynamic viscosity of water based magnetite nanofluid (Fe{sub 3}O{sub 4}/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 (Fe{sub 3}O{sub 4}/water). A comparison between the experimental results and the correlation outputs showed that the proposed model has a suitable accuracy. - Highlights: • Preparing Magnetite nanofluids with solid volume fractions up to 3%. • Measuring viscosity in temperature range of 20–55 °C using Brookfield Viscometer. • Maximum viscosity enhancement occurred at volume fraction of 3% and was 129.7%. • Proposing new correlation to predict the viscosity of Fe3O4/water nanofluid.

  12. Evaluation of bolus electron conformal therapy compared with conventional techniques for the treatment of left chest wall postmastectomy in patients with breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Opp, Dan, E-mail: Daniel.Opp@moffitt.org; Forster, Kenneth; Li, Weiqi; Zhang, Geoffrey; Harris, Eleanor E.

    2013-01-01

    Postmastectomy radiation (PMRT) lowers local-regional recurrence risk and improves survival in selected patients with breast cancer. The chest wall and lower axilla are technically challenging areas to treat with homogenous doses and normal tissue sparing. This study compares several techniques for PMRT to provide data to guide selection of optimal treatment techniques. Twenty-five consecutive left-sided patients treated postmastectomy were contoured using Radiation Therapy Oncology Group (RTOG) atlas guidelines then planned using 4 different PMRT techniques: opposed tangents with wedges (3-dimensional [3D] wedges), opposed tangents with field-in-field (FiF) modulation, 8-field intensity modulation radiotherapy (IMRT), and custom bolus electron conformal therapy (BolusECT, .decimal, Inc., Sanford, FL). Required planning target volume (PTV) coverage was held constant, and then dose homogeneity and normal tissue dose parameters were compared among the 4 techniques. BolusECT achieved clincally acceptable PTV coverage for 22 out of 25 cases. Compared with either tangential technique, IMRT and BolusECT provided the lowest heart V{sub 25} doses (3.3% ± 0.9% and 6.6% ± 3.2%, respectively with p < 0.0001). FiF had the lowest mean total lung dose (7.3 ± 1.1 Gy, with p = 0.0013), IMRT had the lowest total lung V{sub 20} (10.3% ± 1.6%, p < 0.0001), and BolusECT had the lowest mean heart dose (7.3 ± 2.0 Gy, p = 0.0002). IMRT provided the optimal dose homogeneity and normal tissue sparing compared with all other techniques for the cases in which BolusECT could not achieve acceptable PTV coverage. IMRT generally exposes contralateral breast and lung to slightly higher doses. Optimal PMRT technique depends upon patient anatomy. Patients whose maximal target volume depth is about 5.7 cm or less can be treated with BolusECT-assisted 12 or 15 MeV electron beams. At these energies, BolusECT has comparable dose-volume statistics as IMRT and lower heart V{sub 25} than opposed

  13. 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.

  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. 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.

  17. 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.

  18. Estimation of contrast agent bolus arrival delays for improved reproducibility of liver DCE MRI

    Science.gov (United States)

    Chouhan, Manil D.; Bainbridge, Alan; Atkinson, David; Punwani, Shonit; Mookerjee, Rajeshwar P.; Lythgoe, Mark F.; Taylor, Stuart A.

    2016-10-01

    Delays between contrast agent (CA) arrival at the site of vascular input function (VIF) sampling and the tissue of interest affect dynamic contrast enhanced (DCE) MRI pharmacokinetic modelling. We investigate effects of altering VIF CA bolus arrival delays on liver DCE MRI perfusion parameters, propose an alternative approach to estimating delays and evaluate reproducibility. Thirteen healthy volunteers (28.7  ±  1.9 years, seven males) underwent liver DCE MRI using dual-input single compartment modelling, with reproducibility (n  =  9) measured at 7 days. Effects of VIF CA bolus arrival delays were assessed for arterial and portal venous input functions. Delays were pre-estimated using linear regression, with restricted free modelling around the pre-estimated delay. Perfusion parameters and 7 days reproducibility were compared using this method, freely modelled delays and no delays using one-way ANOVA. Reproducibility was assessed using Bland-Altman analysis of agreement. Maximum percent change relative to parameters obtained using zero delays, were  -31% for portal venous (PV) perfusion, +43% for total liver blood flow (TLBF), +3247% for hepatic arterial (HA) fraction, +150% for mean transit time and  -10% for distribution volume. Differences were demonstrated between the 3 methods for PV perfusion (p  =  0.0085) and HA fraction (p  liver DCE MRI quantification. Pre-estimation of delays with constrained free modelling improved 7 days reproducibility of perfusion parameters in volunteers.

  19. 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.

  20. Dose reduction with adaptive bolus chasing computed tomography angiography.

    Science.gov (United States)

    Cai, Zhijun; Bai, Er-Wei; Wang, Ge; Sharafuddin, Melhem J; Abada, Hicham T

    2010-01-01

    Computed Tomography (CT) has become an effective diagnosis and evaluating tool in clinical; however, its radiation exposure has drawn great attention as more and more CT scans are performed every year. How to reduce the radiation dose and meanwhile keep the resultant CT images diagnosable becomes an important research topic. In this paper, we propose a dose reduction approach along with the adaptive bolus chasing CT Angiography (CTA) techniques, which are capable of tracking the contrast bolus peak over all the blood vessel segments during the CTA scan. By modulating the tube current (and collimator width) online, we can reduce the total radiation dose and maintain the contrast to noise ratio (CNR) of the blood vessel. Numerical experiments on reference DSA data sets show that by using the proposed dose reduction method, the effective radiation dose can be saved about 39%.

  1. 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.

  2. Conservative smoothing versus artificial viscosity

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, C.; Hicks, D.L. [Michigan Technological Univ., Houghton, MI (United States); Swegle, J.W. [Sandia National Labs., Albuquerque, NM (United States). Solid and Structural Mechanics Dept.

    1994-08-01

    This report was stimulated by some recent investigations of S.P.H. (Smoothed Particle Hydrodynamics method). Solid dynamics computations with S.P.H. show symptoms of instabilities which are not eliminated by artificial viscosities. Both analysis and experiment indicate that conservative smoothing eliminates the instabilities in S.P.H. computations which artificial viscosities cannot. Questions were raised as to whether conservative smoothing might smear solutions more than artificial viscosity. Conservative smoothing, properly used, can produce more accurate solutions than the von Neumann-Richtmyer-Landshoff artificial viscosity which has been the standard for many years. The authors illustrate this using the vNR scheme on a test problem with known exact solution involving a shock collision in an ideal gas. They show that the norms of the errors with conservative smoothing are significantly smaller than the norms of the errors with artificial viscosity.

  3. Dosimetric characterization of 3D printed bolus at different infill percentage for external photon beam radiotherapy.

    Science.gov (United States)

    Ricotti, Rosalinda; Ciardo, Delia; Pansini, Floriana; Bazani, Alessia; Comi, Stefania; Spoto, Ruggero; Noris, Samuele; Cattani, Federica; Baroni, Guido; Orecchia, Roberto; Vavassori, Andrea; Alicja Jereczek-Fossa, Barbara

    2017-07-01

    3D printing is rapidly evolving and further assessment of materials and technique is required for clinical applications. We evaluated 3D printed boluses with acrylonitrile butadiene styrene (ABS) and polylactide (PLA) at different infill percentage. A low-cost 3D printer was used. The influence of the air inclusion within the 3D printed boluses was assessed thoroughly both with treatment planning system (TPS) and with physical measurements. For each bolus, two treatment plans were calculated with Monte Carlo algorithm, considering the computed tomography (CT) scan of the 3D printed bolus or modelling the 3D printed bolus as a virtual bolus structure with a homogeneous density. Depth dose measurements were performed with Gafchromic films. High infill percentage corresponds to high density and high homogeneity within bolus material. The approximation of the bolus in the TPS as a homogeneous material is satisfying for infill percentages greater than 20%. Measurements performed with PLA boluses are more comparable to the TPS calculated profiles. For boluses printed at 40% and 60% infill, the discrepancies between calculated and measured dose distribution are within 5%. 3D printing technology allows modulating the shift of the build-up region by tuning the infill percentage of the 3D printed bolus in order to improve superficial target coverage. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  4. Virtual bolus for inversely planned intensity modulated radiotherapy in adjuvant breast cancer treatment; Virtueller Bolus zur inversen Bestrahlungsplanung bei intensitaetsmodulierter Radiotherapie des Mammakarzinoms im Rahmen der adjuvanten Therapie

    Energy Technology Data Exchange (ETDEWEB)

    Thilmann, C.; Grosser, K.H.; Rhein, B.; Zabel, A. [Deutsches Krebsforschungszentrum Heidelberg (Germany). Klinische Kooperationseinheit Strahlentherapie; Wannenmacher, M. [Heidelberg Univ. (Germany). Klinische Radiologie; Debus, J. [Deutsches Krebsforschungszentrum Heidelberg (Germany). Klinische Kooperationseinheit Strahlentherapie; Heidelberg Univ. (Germany). Klinische Radiologie

    2002-03-01

    Background: Intensity modulated radiotherapy (IMRT) provides better sparing of normal tissue. We investigated the feasibility of inverse treatment planning for IMRT in adjuvant radiotherapy for breast cancer. Material and Methods: In addition to radiotherapy planning in conventional technique with tangential wedged 6-MV-photon beams we performed inversely planned IMRT (KonRad trademark). In the CT scans for treatment planning we defined a 10-mm bolus of -60 HE density. The influence of this bolus on planning optimization was determined by optimization without and dose calculation with and without bolus. Dose calculation after dose optimization with bolus was performed using different bolus thickness to determine the influence of the bolus on dose calculation. The results were compared with dose distribution in conventional technique. Results: Inverse optimization with a dose algorithm which considers tissue inhomogeneity results in unintended dose increase at the patient surface. With a virtual 10-mm bolus used for inverse optimization the dose increase was reduced. Thus, skin sparing was identical to conventional planning. The relative dose distribution was negligibly affected by the use of a 10-mm bolus. Difference in absolute dose was 3.4% compared to calculation without bolus. Therefore, the bolus must be removed before final dose calculation. (orig.) [German] Fragestellung: Die intensitaetsmodulierte Strahlenbehandlung (IMRT) verspricht eine verbesserte Schonung von Risikostrukturen. Wir untersuchten, in welcher Form eine inverse Bestrahlungsplanung zur IMRT der Restbrust beim Mammakarzinom durchfuehrbar ist. Methodik: Neben einer Bestrahlungsplanung in konventioneller Technik mit tangentialen 6-MB-Keilfilter-Feldern wurde eine IMRT-Bestrahlungsplanung mit inverser Planoptimierung (KonRad trademark) durchgefuehrt. Im Planungs-CT wurde ein Bolus von 10 mm Dicke und einer Dichte von -60 HE definiert. Der Einfluss des Bolus auf die Planoptimierung wurde bestimmt

  5. Bolus calculator with nutrition database software, a new concept of prandial insulin programming for pump users.

    Science.gov (United States)

    Pańkowska, Ewa; Błazik, Marlena

    2010-05-01

    Bolus calculators are effective tools in controlling blood glucose levels in patients treated with insulin. Diabetics is a new software devised for patients to facilitate and improve self-managing for prandial insulin dosing and for better controlling food intake. This device contains two integral parts: a nutrition database and a bolus calculator. The algorithm is based on a formula in which carbohydrate (CHO) and either fat and/or protein (FP) products are engulfed in insulin. The insulin dose setting is programmed individually for CHO in a normal bolus (N-W) and for FP in a square-wave bolus (S-W). The device calculates the dose of insulin for N-W or S-W, suggests the optimal kind of bolus, and indicates the timing in hours for an S-W bolus. In addition, this calculator, which contains a nutrition database and insulin dosing software, helps determine the correct type of necessary boluses for selected foods.

  6. Comparison of Super Stuff and paraffin wax bolus in radiation therapy of irregular surfaces.

    Science.gov (United States)

    Humphries, S M; Boyd, K; Cornish, P; Newman, F D

    1996-01-01

    Irregular facial contours can make radiation therapy of head and neck tumors difficult. Isodose lines become skewed, making treatment planning complex. A traditional solution to this problem is the paraffin wax box bolus. Such a bolus is made to fit the irregular surface compensating for the topology and creating an even surface. The fabrication of a wax bolus can be a difficult and time-consuming process. A method that is simple and efficient has been devised. Super Stuff bolus can be easily molded and has approximately the same effect as a similar paraffin wax bolus. This was verified by irradiating a Rando head phantom with both a paraffin wax bolus and a Super Stuff bolus. Doses to various points of interest were measured with thermoluminescent dosimetry (TLD) chips (LiF). The particular case addressed is malignant melanoma of the nasal septum, but the technique described can be useful in the treatment of other sites as well.

  7. A customized bolus produced using a 3-dimensional printer for radiotherapy.

    Directory of Open Access Journals (Sweden)

    Shin-Wook Kim

    Full Text Available OBJECTIVE: Boluses are used in high-energy radiotherapy in order to overcome the skin sparing effect. In practice though, commonly used flat boluses fail to make a perfect contact with the irregular surface of the patient's skin, resulting in air gaps. Hence, we fabricated a customized bolus using a 3-dimensional (3D printer and evaluated its feasibility for radiotherapy. METHODS: We designed two kinds of bolus for production on a 3D printer, one of which was the 3D printed flat bolus for the Blue water phantom and the other was a 3D printed customized bolus for the RANDO phantom. The 3D printed flat bolus was fabricated to verify its physical quality. The resulting 3D printed flat bolus was evaluated by assessing dosimetric parameters such as D1.5 cm, D5 cm, and D10 cm. The 3D printed customized bolus was then fabricated, and its quality and clinical feasibility were evaluated by visual inspection and by assessing dosimetric parameters such as Dmax, Dmin, Dmean, D90%, and V90%. RESULTS: The dosimetric parameters of the resulting 3D printed flat bolus showed that it was a useful dose escalating material, equivalent to a commercially available flat bolus. Analysis of the dosimetric parameters of the 3D printed customized bolus demonstrated that it is provided good dose escalation and good contact with the irregular surface of the RANDO phantom. CONCLUSIONS: A customized bolus produced using a 3D printer could potentially replace commercially available flat boluses.

  8. Effect of a bitter bolus on oral, pharyngeal and esophageal transit of healthy subjects.

    Science.gov (United States)

    Alves, Leda Maria Tavares; Secaf, Marie; Dantas, Roberto Oliveira

    2013-01-01

    During swallowing, boluses stimulate sensory receptors of the oral, pharyngeal, laryngeal, and esophageal regions. Sweet and tasteless foods are more acceptable for swallowing than bitter foods. A bitter bolus is unpleasant for most subjects. Our hypothesis was that the ingestion of a bitter bolus might alter the oral behavior, pharyngeal and esophageal transit when compared to a sweet bolus. To evaluate whether the bitter taste of a liquid bolus causes alteration on oral, pharyngeal and/or esophageal transit in normal subjects in comparison with sweet bolus.' Scintigraphic evaluation of oral, pharyngeal and esophageal transit was performed in 43 asymptomatic subjects, 22 women and 21 men, ages 23-71 years, without problems with the ingestion of liquid and solid foods, and without digestive, cardiac or neurologic diseases. Each subject swallowed in random sequence and at room temperature 5 mL of a liquid bolus with bitter taste, prepared with 50 mL of water with 2 g of leaves of Peumus boldus, heated until boiling (boldus tea), and 5 mL of a liquid bolus with sweet taste, prepared with 50 mL of water with 3 g of sucrose, both labeled with 37 MBq of technetium phytate (Tc99m). There was no difference between the bitter bolus and the sweet bolus in mouth, pharynx and esophageal transit and clearance duration and in the amount of residues. A bitter bolus, considered an unpleasant bolus, does not alter the duration of oral, pharyngeal and esophageal phases of swallowing, when compared with a sweet bolus, considered a pleasant bolus.

  9. EFFECT OF A BITTER BOLUS ON ORAL, PHARYNGEAL AND ESOPHAGEAL TRANSIT OF HEALTHY SUBJECTS

    Directory of Open Access Journals (Sweden)

    Leda Maria Tavares ALVES

    2013-03-01

    Full Text Available Context During swallowing, boluses stimulate sensory receptors of the oral, pharyngeal, laryngeal, and esophageal regions. Sweet and tasteless foods are more acceptable for swallowing than bitter foods. A bitter bolus is unpleasant for most subjects. Our hypothesis was that the ingestion of a bitter bolus might alter the oral behavior, pharyngeal and esophageal transit when compared to a sweet bolus. Objective To evaluate whether the bitter taste of a liquid bolus causes alteration on oral, pharyngeal and/or esophageal transit in normal subjects in comparison with sweet bolus.' Method Scintigraphic evaluation of oral, pharyngeal and esophageal transit was performed in 43 asymptomatic subjects, 22 women and 21 men, ages 23-71 years, without problems with the ingestion of liquid and solid foods, and without digestive, cardiac or neurologic diseases. Each subject swallowed in random sequence and at room temperature 5 mL of a liquid bolus with bitter taste, prepared with 50 mL of water with 2 g of leaves of Peumus boldus, heated until boiling (boldus tea, and 5 mL of a liquid bolus with sweet taste, prepared with 50 mL of water with 3 g of sucrose, both labeled with 37 MBq of technetium phytate (Tc99m. Results There was no difference between the bitter bolus and the sweet bolus in mouth, pharynx and esophageal transit and clearance duration and in the amount of residues. Conclusion A bitter bolus, considered an unpleasant bolus, does not alter the duration of oral, pharyngeal and esophageal phases of swallowing, when compared with a sweet bolus, considered a pleasant bolus.

  10. A Customized Bolus Produced Using a 3-Dimensional Printer for Radiotherapy

    Science.gov (United States)

    Kim, Shin-Wook; Shin, Hun-Joo; Kay, Chul Seung; Son, Seok Hyun

    2014-01-01

    Objective Boluses are used in high-energy radiotherapy in order to overcome the skin sparing effect. In practice though, commonly used flat boluses fail to make a perfect contact with the irregular surface of the patient’s skin, resulting in air gaps. Hence, we fabricated a customized bolus using a 3-dimensional (3D) printer and evaluated its feasibility for radiotherapy. Methods We designed two kinds of bolus for production on a 3D printer, one of which was the 3D printed flat bolus for the Blue water phantom and the other was a 3D printed customized bolus for the RANDO phantom. The 3D printed flat bolus was fabricated to verify its physical quality. The resulting 3D printed flat bolus was evaluated by assessing dosimetric parameters such as D1.5 cm, D5 cm, and D10 cm. The 3D printed customized bolus was then fabricated, and its quality and clinical feasibility were evaluated by visual inspection and by assessing dosimetric parameters such as Dmax, Dmin, Dmean, D90%, and V90%. Results The dosimetric parameters of the resulting 3D printed flat bolus showed that it was a useful dose escalating material, equivalent to a commercially available flat bolus. Analysis of the dosimetric parameters of the 3D printed customized bolus demonstrated that it is provided good dose escalation and good contact with the irregular surface of the RANDO phantom. Conclusions A customized bolus produced using a 3D printer could potentially replace commercially available flat boluses. PMID:25337700

  11. 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.

  12. Excess Molar Volume, Viscosity and Heat Capacity for the Mixture of 1,2-Propanediol-Water at Different Temperatures%1,2-丙二醇水溶液在不同温度下的超额摩尔体积黏度和热容

    Institute of Scientific and Technical Information of China (English)

    杨长生; 马沛生; 唐多强; 靳凤民

    2003-01-01

    Experimental densities, viscosities and heat capacities at different temperatures were presented over the entire mole fraction range for the binary mixture of 1,2-propanediol and water. Density values were used in the determination of excess molar volumes, VE. At the same time, the excess viscosity was investigated. The values of VE and ηE were fitted to the Redlich-Kister equation. Good agreement was observed. The excess volumes are negative over the entire range of composition. They show an U-shaped-concentration dependence and decrease in absolute values with increase of temperature. Values of ηE are negative over the entire range of the composition, and has a trend very similar to that of VE . The analysis shows that at any temperature the specific heat of mixture is a linear function of the composition as x1>20%. All the extended lines intersect at one point. An empirical equation is obtained to calculate the specific heat to mixture at any composition and temperature in the experimental range.

  13. Viscosity Measurement for Tellurium Melt

    Science.gov (United States)

    Lin, Bochuan; Li, Chao; Ban, Heng; Scripa, Rosalia N.; Su, Ching-Hua; Lehoczky, Sandor L.

    2006-01-01

    The viscosity of high temperature Te melt was measured using a new technique in which a rotating magnetic field was applied to the melt sealed in a suspended ampoule, and the torque exerted by rotating melt flow on the ampoule wall was measured. Governing equations for the coupled melt flow and ampoule torsional oscillation were solved, and the viscosity was extracted from the experimental data by numerical fitting. The computational result showed good agreement with experimental data. The melt velocity transient initiated by the rotating magnetic field reached a stable condition quickly, allowing the viscosity and electrical conductivity of the melt to be determined in a short period.

  14. 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.

  15. Viscosity of particle laden films

    Science.gov (United States)

    Timounay, Yousra; Rouyer, Florence

    2017-06-01

    We perform retraction experiments on soap films where large particles bridge the two interfaces. Local velocities are measured by PIV during the unstationnary regime. The velocity variation in time and space can be described by a continuous fluid model from which effective viscosity (shear and dilatational) of particulate films is measured. The 2D effective viscosity of particulate films η2D increases with particle surface fraction ϕ: at low ϕ, it tends to the interfacial dilatational viscosity of the liquid/air interfaces and it diverges at the critical particle surface fraction ϕc ≃ 0.84. Experimental data agree with classical viscosity laws of hard spheres suspensions adapted to the 2D geometry, assuming viscous dissipation resulting from the squeeze of the liquid/air interfaces between the particles. Finally, we show that the observed viscous dissipation in particulate films has to be considered to describe the edge velocity during a retraction experiment at large particle coverage.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. A tracer bolus method for investigating glutamine kinetics in humans.

    Directory of Open Access Journals (Sweden)

    Maiko Mori

    Full Text Available Glutamine transport between tissues is important for the outcome of critically ill patients. Investigation of glutamine kinetics is, therefore, necessary to understand glutamine metabolism in these patients in order to improve future intervention studies. Endogenous glutamine production can be measured by continuous infusion of a glutamine tracer, which necessitates a minimum measurement time period. In order to reduce this problem, we used and validated a tracer bolus injection method. Furthermore, this method was used to measure the glutamine production in healthy volunteers in the post-absorptive state, with extra alanine and with glutamine supplementation and parenteral nutrition. Healthy volunteers received a bolus injection of [1-13C] glutamine, and blood was collected from the radial artery to measure tracer enrichment over 90 minutes. Endogenous rate of appearance (endoRa of glutamine was calculated from the enrichment decay curve and corrected for the extra glutamine supplementation. The glutamine endoRa of healthy volunteers was 6.1±0.9 µmol/kg/min in the post-absorptive state, 6.9±1.0 µmol/kg/min with extra alanyl-glutamine (p = 0.29 versus control, 6.1±0.4 µmol/kg/min with extra alanine only (p = 0.32 versus control, and 7.5±0.9 µmol/kg/min with extra alanyl-glutamine and parenteral nutrition (p = 0.049 versus control. In conclusion, a tracer bolus injection method to measure glutamine endoRa showed good reproducibility and small variation at baseline as well as during parenteral nutrition. Additionally, we showed that parenteral nutrition including alanyl-glutamine increased glutamine endoRa in healthy volunteers, which was not attributable to the alanine part of the dipeptide.

  1. Measurement of the dynamic viscosity of hybrid engine oil -Cuo-MWCNT nanofluid, development of a practical viscosity correlation and utilizing the artificial neural network

    Science.gov (United States)

    Aghaei, Alireza; Khorasanizadeh, Hossein; Sheikhzadeh, Ghanbar Ali

    2017-07-01

    The main objectives of this study have been measurement of the dynamic viscosity of CuO-MWCNTs/SAE 5w-50 hybrid nanofluid, utilization of artificial neural networks (ANN) and development of a new viscosity model. The new nanofluid has been prepared by a two-stage procedure with volume fractions of 0.05, 0.1, 0.25, 0.5, 0.75 and 1%. Then, utilizing a Brookfield viscometer, its dynamic viscosity has been measured for temperatures of 5, 15, 25, 35, 45, 55 °C. The experimental results demonstrate that the viscosity increases by increasing the nanoparticles volume fraction and decreases by increasing temperature. Based on the experimental data the maximum and minimum nanofluid viscosity enhancements, when the volume fraction increases from 0.05 to 1, are 35.52% and 12.92% for constant temperatures of 55 and 15 °C, respectively. The higher viscosity of oil engine in higher temperatures is an advantage, thus this result is important. The measured nanofluid viscosity magnitudes in various shear rates show that this hybrid nanofluid is Newtonian. An ANN model has been employed to predict the viscosity of the CuO-MWCNTs/SAE 5w-50 hybrid nanofluid and the results showed that the ANN can estimate the viscosity efficiently and accurately. Eventually, for viscosity estimation a new temperature and volume fraction based third-degree polynomial empirical model has been developed. The comparison shows that this model is in good agreement with the experimental data.

  2. Viscosity and density of methanol/water mixtures at low temperatures

    Science.gov (United States)

    Austin, J. G.; Kurata, F.; Swift, G. W.

    1968-01-01

    Viscosity and density are measured at low temperatures for three methanol/water mixtures. Viscosity is determined by a modified falling cylinder method or a calibrated viscometer. Density is determined by the volume of each mixture contained in a calibrated glass cell placed in a constant-temperature bath.

  3. Method of preparing a high solids content, low viscosity ceramic slurry

    Science.gov (United States)

    Tiegs, Terry N.; Wittmer, Dale E.

    1995-01-01

    A method for producing a high solids content, low viscosity ceramic slurry composition comprises turbomilling a dispersion of a ceramic powder in a liquid to form a slurry having a viscosity less than 100 centipoise and a solids content equal to or greater than 48 volume percent.

  4. 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.

  5. Comparison of bolus remifentanil versus bolus fentanyl for blunting cardiovascular intubation responses in children: a randomized, double-blind study

    Institute of Scientific and Technical Information of China (English)

    YANG Quan-yong; XUE Fu-shan; LIAO Xu; LIU He-ping; LUO Mao-ping; XU Ya-chao; LIU Yi; ZHANG Yan-ming

    2009-01-01

    Background The authors found no study to compare the efficacy of bolus dose fentanyl and remifentanil blunting the cardiovascular intubation response in children, so they designed this randomized, double-blind clinical study to assess the effects of remifentanil 2 ug/kg and fentanyl 2 ug/kg by bolus injection on the cardiovascular intubation response in healthy children.Methods One hundred and two children, the American Society of Anesthesiologists (ASA) physical status 1-2 and scheduled for elective plastic surgery under general anesthesia, were randomly divided into one of two groups to receive the following treatments in a double blind manner: remifentanil 2 ug/kg (Group R) and fentanyl 2 ug/kg (Group F) when anesthesia was induced with propofol and vecuronium. The orotracheal intubation was performed using a direct laryngoscope. Blood pressure (BP) and heart rate (HR) were recorded before anesthesia induction (baseline values), immediately before intubation, at intubation and every minute for 5 minutes after intubation. The percent changes of systolic blood pressure (SBP) and HR relative to baseline values and the rate pressure product (RPP) at every observing point were calculated. The incidences of SBP and HR percent changes >30% of baseline values and RPP >22 000 during the observation were recorded. Results There were no significant differences between groups in the demographic data, baseline values of BP and HR and the intubation time. As compared to baseline values, BP, HR and RPP at intubation and their maximum values during observation increased significantly in Group F, but they all decreased significantly in Group R. BP, HR and RPP at all observed points, and their maximum values during the observation, were significantly different between groups. There were also significant differences between groups in the percent change of SBP and HR relative to baseline values at all observed points and their maximum percent changes during the observation. The

  6. Split-bolus MR urography: synchronous visualization of obstructing vessels and collecting system in children.

    Science.gov (United States)

    Battal, Bilal; Kocaoğlu, Murat; Akgün, Veysel; İnce, Selami; Gök, Faysal; Taşar, Mustafa

    2015-01-01

    Several vascular abnormalities related with urinary system such as crossing accessory renal vessels, retroiliac ureters, retrocaval ureters, posterior nutcracker syndrome, and ovarian vein syndrome may be responsible for urinary collecting system obstruction. Split-bolus magnetic resonance urography (MRU) using contrast material as two separate bolus injections provides superior demonstration of the collecting system and obstructing vascular anomalies simultaneously and enables accurate preoperative radiologic diagnosis. In this pictorial review we aimed to outline the split-bolus MRU technique in children, list the coexisting congenital collecting system and vascular abnormalities, and exhibit the split-bolus MRU appearances of concurrent urinary collecting system and vascular abnormalities.

  7. 21 CFR 520.1802b - Piperazine-carbon disulfide complex boluses.

    Science.gov (United States)

    2010-04-01

    ...) per 500 pounds body weight; removal of large strongyles, pinworms, and bots, 1 bolus per 250 pounds...), large strongyles (Strongylus spp.) bots (Gastrophilus spp.), small strongyles, and pinworms...

  8. Intestinal propulsion of a solid non-deformable bolus.

    Science.gov (United States)

    Miftahof, R; Fedotov, E

    2005-07-01

    A mathematical model of a segment of the gut with an enclosed pellet is constructed. The gut is represented as a thin deformable soft biological shell with the pellet modeled as a non-deformable solid. Mechanical properties of the gut wall were represented as longitudinal and circular smooth muscle layers embedded in stroma that satisfies the general type of nonlinear orthotropy. Deformations of the wall are finite. Bolus propulsion is numerically simulated by generation and propagation of an electromechanical wave along the syncytia. Pharmacological manipulation is applied to model 5-HT type 3 antagonist (Lotronex, GlaxoSmithKline) and 5-HT type 4 agonist (Zelnorm, Novartis, AB) drugs on the dynamics of bolus progression. The results lead to new quantitative insights into the complex spatio-temporal patterns of gastrointestinal transit. It is demonstrated that the reciprocal relationship in contraction of the longitudinal and circular smooth muscle syncytia is necessary to provide the "mixing" type of movements during the preparatory phase of propulsion. Strong simultaneous contractions of the both smooth muscle layers are required to expel the "mixed" pellet from the segment. The model is implemented as an interactive software system, Gut Discovery(www.aincompany.com), and accurately predicts the effects of drugs on gut motility.

  9. 1,2-丙二醇+丁醇/戊醇/己醇二元系的过量体积和黏度%Excess Molar Volumes and Viscosities of Binary Mixtures Composed of 1,2-Propanediol with Butanol, Pentanol or Hexanol

    Institute of Scientific and Technical Information of China (English)

    凌锦龙; 李灵; 杨佳琳

    2016-01-01

    常压下测定了1,2-丙二醇分别与丁醇、戊醇和己醇组成的二元系在293.15~318.15 K下的密度和黏度,建立了混合液密度和黏度随温度和组成变化的方程。计算了过量摩尔体积VE,黏度偏差∆η和过量流动活化自由能∆G*E。结果表明,三个二元系的过量摩尔体积在全浓度范围内均为正值,随温度升高,偏差增大,但发生最大偏差时的溶液组成不同;过量摩尔体积值按丁醇-戊醇-己醇顺序逐渐增大;黏度偏差和过量流动活化自由能三个体系显示了相同的变化关系,均为负值,且都随温度降低而偏差增大。利用Redlich-Kister方程对过量性质进行了关联。分析和讨论了分子间相互作用。%The densities and viscosities of binary mixtures consisting of butanol, pentanol or hexanol with 1,2-propanediol(12PD) were measured using pycnometer and Ubbelohde viscometer at 293.15~318.15 K under atmospheric pressure. The density and viscosity data of the binary mixtures were fitted as functions of composition and temperature. Excess molar volumes (VE), viscosity deviations (∆η) and excess Gibbs energy of activation of viscous flow (∆G*E) were calculated from the experimental data. The results show that the excess molar volumes are positive over the whole mole fraction range in the temperature range studied for all of the binary mixtures, and the deviation increases as temperature increases. However, the largest deviation varies in different solution compositions. The excess molar volume value increases following an order of butanol - pentanol – hexanol. Both∆η and∆G*E are negative over the whole mole fraction range in the temperature range studied for all of the binary mixtures, and the deviation increases as temperature decreases. All of the excess properties are correlated by the Redlich-Kister equation and the molecular interactions are analyzed.

  10. 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.

  11. Dependence of Nanofluid Viscosity on Particle Size and pH Value

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jia-Fei; LUO Zhong-Yang; NI Ming-Jiang; CEN Ke-Fa

    2009-01-01

    We investigate the viscosity of silicon dioxide nanofluid at different particle sizes and pH values considering nanoparticle aggregation.The experimental and simulation results indicate that nanoparticle size is of crucial importance to the viscosity of the nanofluid due to aggregation.As the nanoparticle size decreases,the viscosity becomes much more dependent on the volume fraction.Moreover,when the nanoparticle diameter is smaller than 20 rim,the viscosity is closely related to the pH of the nanofluid,and fluctuates with pH values from 5 and 7.

  12. Viscosity of liquid undercooled tungsten

    Science.gov (United States)

    Paradis, Paul-François; Ishikawa, Takehiko; Yoda, Shinichi

    2005-05-01

    Knowledge of the viscosity and its temperature dependence is essential to improve metallurgical processes as well as to validate theoretical and empirical models of liquid metals. However, data for metals with melting points above 2504K could not be determined yet due to contamination and containment problems. Here we report the viscosity of tungsten, the highest melting point metal (3695K), measured by a levitation technique. Over the 3350-3700-K temperature range, which includes the undercooled region by 345K, the viscosity data could be fitted as η(T )=0.108exp[1.28×105/(RT)](mPas). At the melting point, the datum agrees with the proposed theoretical and empirical models of liquid metals but presents atypical temperature dependence, suggesting a basic change in the mechanism of momentum transfer.

  13. 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...

  14. Qualitative indices and enhancement rate of CT pulmonary angiography in patients with suspected pulmonary embolism: Comparison between test bolus and bolus-tracking methods

    Directory of Open Access Journals (Sweden)

    Maryam Moradi

    2016-01-01

    Full Text Available Background: The aim of the present study was to assess the qualitative indices and enhancement rate of computed tomographic pulmonary angiography (CTPA in patients with suspected pulmonary embolism using Test bolus and Bolus-tracking techniques. Materials and Methods: Fifty-two patients with suspected pulmonary embolism that passed informed consent were randomly divided in the two groups. In each group, demographic characteristics, qualitative indices, and enhancement rate of CTPA were recorded. Results: The diagnostic result obtained in majority of the participants in the two groups (88.5 % in Test bolus group vs. 73.1% in the Bolus tracking group. In the case of quantitative variables, no statistically significant differences were found between the groups (P > 0.05. The only statistically significant difference between the two groups is average of "X-ray dose". Conclusion: The results of our study show that there is no statistically significant difference between the Bolus Tracking and Test Bolus techniques for producing more homogeneous enhancement.

  15. Efficacy of intraruminal albendazole boluses against Dicrocoelium dendriticum in sheep.

    Science.gov (United States)

    Corba, J; Krupicer, I

    1992-01-01

    The anthelmintic potential of albendazole (ABZ) in intraruminal boluses (Proftril-Captec) was investigated in sheep harbouring naturally acquired Dicrocoelium infection. The anthelmintic efficacy was assessed by coprological testing during the autumn pasture and comparison of worm counts in 22 necropsied animals (11 treated and 11 untreated) at the end of the experiment. The mean faecal egg count (EPG) in treated animals dropped significantly during week 2, and between the 4th and the 12th week the faecal samples were almost negative. The health status of treated animals improved significantly during the first 2 weeks. Helminthological dissection of livers and small intestines revealed 91.8% efficacy, but a small number of live adult flukes were found in all treated animals.

  16. Bulk viscosity and deflationary universes

    CERN Document Server

    Lima, J A S; Waga, I

    2007-01-01

    We analyze the conditions that make possible the description of entropy generation in the new inflationary model by means of a nearequilibrium process. We show that there are situations in which the bulk viscosity cannot describe particle production during the coherent field oscillations phase.

  17. 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...

  18. 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...

  19. 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.

  20. 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.

  1. Structural properties of aqueous metoprolol succinate solutions. Density, viscosity, and refractive index at 311 K

    Science.gov (United States)

    Deosarkar, S. D.; Kalyankar, T. M.

    2013-06-01

    Density, viscosity and refractive index of aqueous solutions of metoprolol succinate of different concentrations (0.005-0.05 mol dm-3) were measured at 38°C. Apparent molar volume of resultant solutions were calculated and fitted to the Masson's equation and apparent molar volume at infinite dilution was determined graphically. Viscosity data of solutions has been fitted to the Jone-Dole equation and viscosity A- and B-coefficients were determined graphically. Physicochemical data obtained were discussed in terms of molecular interactions.

  2. Mathematical modeling of normal pharyngeal bolus transport: a preliminary study.

    Science.gov (United States)

    Chang, M W; Rosendall, B; Finlayson, B A

    1998-07-01

    Dysphagia (difficulty in swallowing) is a common clinical symptom associated with many diseases, such as stroke, multiple sclerosis, neuromuscular diseases, and cancer. Its complications include choking, aspiration, malnutrition, cachexia, and dehydration. The goal in dysphagia management is to provide adequate nutrition and hydration while minimizing the risk of choking and aspiration. It is important to advance the individual toward oral feeding in a timely manner to enhance the recovery of swallowing function and preserve the quality of life. Current clinical assessments of dysphagia are limited in providing adequate guidelines for oral feeding. Mathematical modeling of the fluid dynamics of pharyngeal bolus transport provides a unique opportunity for studying the physiology and pathophysiology of swallowing. Finite element analysis (FEA) is a special case of computational fluid dynamics (CFD). In CFD, the flow of a fluid in a space is modeled by covering the space with a grid and predicting how the fluid moves from grid point to grid point. FEA is capable of solving problems with complex geometries and free surfaces. A preliminary pharyngeal model has been constructed using FEA. This model incorporates literature-reported, normal, anatomical data with time-dependent pharyngeal/upper esophageal sphincter (UES) wall motion obtained from videofluorography (VFG). This time-dependent wall motion can be implemented as a moving boundary condition in the model. Clinical kinematic data can be digitized from VFG studies to construct and test the mathematical model. The preliminary model demonstrates the feasibility of modeling pharyngeal bolus transport, which, to our knowledge, has not been attempted before. This model also addresses the need and the potential for CFD in understanding the physiology and pathophysiology of the pharyngeal phase of swallowing. Improvements of the model are underway. Combining the model with individualized clinical data should potentially

  3. MO-H-19A-03: Patient Specific Bolus with 3D Printing Technology for Electron Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Zou, W; Swann, B; Siderits, R; McKenna, M; Khan, A; Yue, N; Zhang, M [Rutgers University, New Brunswick, NJ (United States); Fisher, T [Memorial Medical Center, Modesto, CA (United States)

    2014-06-15

    Purpose: Bolus is widely used in electron radiotherapy to achieve desired dose distribution. 3D printing technologies provide clinicians with easy access to fabricate patient specific bolus accommodating patient body surface irregularities and tissue inhomogeneity. This study presents the design and the clinical workflow of 3D printed bolus for patient electron therapy in our clinic. Methods: Patient simulation CT images free of bolus were exported from treatment planning system (TPS) to an in-house developed software package. Bolus with known material properties was designed in the software package and then exported back to the TPS as a structure. Dose calculation was carried out to examine the coverage of the target. After satisfying dose distribution was achieved, the bolus structure was transferred in Standard Tessellation Language (STL) file format for the 3D printer to generate the machine codes for printing. Upon receiving printed bolus, a quick quality assurance was performed with patient resimulated with bolus in place to verify the bolus dosimetric property before treatment started. Results: A patient specific bolus for electron radiotherapy was designed and fabricated in Form 1 3D printer with methacrylate photopolymer resin. Satisfying dose distribution was achieved in patient with bolus setup. Treatment was successfully finished for one patient with the 3D printed bolus. Conclusion: The electron bolus fabrication with 3D printing technology was successfully implemented in clinic practice.

  4. A Bolus Calculator Based on Continuous-Discrete Unscented Kalman Filtering for Type 1 Diabetics

    DEFF Research Database (Denmark)

    Boiroux, Dimitri; Aradóttir, Tinna Björk; Hagdrup, Morten

    2015-01-01

    both reduces the risk of hypoglycemia in case of an overestimated meal and the time spent in hyperglycemia if the meal size is underestimated. Faster insulin and the use of glucagon will have the potential to encourage postprandial meal bolus administration and hence will not require to accurately......In patients with type 1 diabetes, the effects of meals intake on blood glucose level are usually mitigated by administering a large amount of insulin (bolus) at mealtime or even slightly before. This strategy assumes, among other things, a prior knowledge of the meal size and the postprandial...... glucose dynamics. On the other hand, administering the meal bolus during or after mealtime could benefit from the information provided by the postprandial meal dynamics at the expense of a delayed meal bolus. The present paper investigates different bolus administration strategies (at mealtime, 15 minutes...

  5. A presedation fluid bolus does not decrease the incidence of propofol-induced hypotension in pediatric patients.

    Science.gov (United States)

    Jager, Matthew D; Aldag, Jean C; Deshpande, Girish G

    2015-02-01

    Propofol is commonly used in pediatric sedation, which may cause hypotension during induction. Our goal was to determine the effect of a preinduction 20-mL/kg isotonic fluid bolus on propofol-induced hypotension, assess clinical signs of hypoperfusion during hypotension, and evaluate for age-related propofol dosing differences. This prospective, randomized, controlled, nonblinded study was conducted at Children's Hospital of Illinois. Patients were children 6 to 60 months of age who needed sedation for MRI or auditory brainstem-evoked response testing. The treatment group received a preinduction 20-mL/kg isotonic saline bolus before procedure initiation. Patients were continuously monitored via cardiorespiratory monitor with pulse oximetry and end-tidal carbon dioxide measurements. Cardiovascular indices and clinical signs of hypoperfusion were compared between groups, and propofol dosing differences were compared between age groups. One hundred twenty-six patients were randomly assigned to treatment (n=52) or control (n=74) conditions. Twelve patients in the treatment group and 14 patients in the control group experienced postinduction hypotension, as defined by the Pediatric Advanced Life Support guidelines. One patient in each group was given volume resuscitation when blood pressure did not improve after a reduction in the propofol infusion rate. No hypotensive patients had physical signs of hypoperfusion, and patients≤1 year of age needed significantly more propofol. A 20-mL/kg preinduction isotonic saline bolus does not prevent propofol-induced hypotension. No clinical signs of hypoperfusion were noted with induced hypotension, and infants≤12 months old need significantly more propofol per kilogram for procedures. Copyright © 2015 by the American Academy of Pediatrics.

  6. Contrast agent bolus tracking with a fixed threshold or a manual fast start for coronary CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Stenzel, Fabian; Rief, Matthias; Zimmermann, Elke; Greupner, Johannes; Richter, Felicitas; Dewey, Marc [Charite - Universitaetsmedizin Berlin, Department of Radiology, Berlin (Germany)

    2014-06-15

    Comparison of bolus tracking with a fixed threshold versus a manual fast start for coronary CT angiography. We retrospectively analysed 320-row coronary CT angiography of 50 patients with suspected or known coronary artery disease. Twenty-five examinations were initiated by a bolus tracking method (group 1), 25 examinations with a manual fast surestart (group 2). Mean attenuation values in the ascending aorta were 519 ± 111 Hounsfield units (HU) in group 1 and 476 ± 65 HU in group 2 (p = 0.10). Assessable vessel lengths were 171 ± 44 mm vs 172 ± 29 mm for the right coronary artery (p = 0.91), 11 ± 4 mm vs 12 ± 4 mm for the left main (p = 0.9), 163 ± 28 mm vs 151 ± 26 mm for the left anterior descending coronary artery (p = 0.11) and 125 ± 41 mm vs 110 ± 37 mm for the left circumflex coronary artery (p = 0.18). Image quality for all coronary arteries was not significantly different between the groups (p > 0.41). The attenuation ratio between the left and right ventricle was 2.8 ± 0.7 vs 3.6 ± 1.0 (p = 0.003). Significantly less contrast agent was used in group 2 (64 ± 6 ml vs 80 ± 0 ml; p < 0.001). Bolus tracking with a fixed threshold and with a manual fast start are both suitable methods; the fast start allowed a reduction of contrast agent volumes. (orig.)

  7. 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.

  8. Excess Molar Volume, Refractive Index and Viscosity of N-Butylpyridinium Tetrafluoroborate Ionic Liquid + Methanol Binary System%离子液体[BPy]BF4和甲醇二元混合体系的超额摩尔体积、折射率和黏度

    Institute of Scientific and Technical Information of China (English)

    许映杰; 黄钗英; 李浩然

    2011-01-01

    合成了室温离子液体N-丁基吡啶四氟硼酸盐([BPy]BF4),通过核磁共振1H-NMR和红外光谱IR对其结构进行了表征.在298.15 K和常压下,采用U形振荡管密度计测定[BPy]BF4-甲醇体系的密度;用阿贝尔折射仪测定了该二元混合体系在相同温度和压力下的折射率;用乌氏黏度计测定了该二元混合体系在相同温度和压力下的黏度,并由密度数据计算出超额摩尔体积(VE)、由折射率数据计算出了折射率改变值(△nD)、由黏度数据计算出了体系的黏度B系数.结果表明:[BPy]BF4-甲醇体系的VE在全浓度范围内为负值,而△nD在全浓度范围内为正值,两者均在摩尔分数x1≈0.4处出现极值;采用Redlich-Kister方程对VE、△nD与组成的关系进行了关联,最大标准偏差小于3%,说明此方程可适用于回归该二元体系上述的物性数据.由Jones-Dole方程计算出体系的黏度B系数为0.35608,这表明甲醇有效地降低了离子液体的黏度.%Room temperature ionic liquid N-butylpyridinium tetrafluoroborate ([BPy]BF4) was synthesized, and its structure was characterized and confirmed by 1H-NMR and IR. The densities and refractive indices of binary mixtures ([BPy]BF4+methanol) with different compositions were determined at T= 298.15 K and under atmospheric pressure by using a vibrating U-shaped sample tube densimeter and semi-automatic refractometer,respectively. The viscosities of the mixtures were also determined at T= 298.15 K and under atmospheric pressure by using Ubbelohde Suspended-level viscometer. Density values were used in the calculation of the excess molar volumes (V E), and the refractive indices were used to calculate the changes of refractive index (△nD). The achieved viscosities were used to calculate the viscosity B coefficient of the mixtures. The results show that the values of VE are negative over the entire composition range, while the △nD are positive. When the mole fraction of [BPy]BF4

  9. 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.

  10. Split-bolus CT-urography using dual-energy CT: Feasibility, image quality and dose reduction

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, Mitsuru, E-mail: m2rbimn@gmail.com [Nagoya City University Graduate School of Medical Sciences, Department of Radiology, 1 Kawasumi Mizuho-cho, Mizuho-ku, Nagoya, 467-8601 (Japan); Kawai, Tatsuya; Ito, Masato; Ogawa, Masaki [Nagoya City University Graduate School of Medical Sciences, Department of Radiology, 1 Kawasumi Mizuho-cho, Mizuho-ku, Nagoya, 467-8601 (Japan); Ohashi, Kazuya [Nagoya City University Hospital, Department of Radiology, 1 Kawasumi Mizuho-cho, Mizuho-ku, Nagoya, 467-8601 (Japan); Hara, Masaki; Shibamoto, Yuta [Nagoya City University Graduate School of Medical Sciences, Department of Radiology, 1 Kawasumi Mizuho-cho, Mizuho-ku, Nagoya, 467-8601 (Japan)

    2012-11-15

    Purpose: To prospectively evaluate the feasibility of dual-energy (DE) split-bolus CT-urography (CTU) and the quality of virtual non-enhanced images (VNEI) and DE combined nephrographic-excretory phase images (CNEPI), and to estimate radiation dose reduction if true non-enhanced images (TNEI) could be omitted. Patients and methods: Between August and September 2011, 30 consecutive patients with confirmed or suspected urothelial cancer or with hematuria underwent DE CT. Single-energy TNEI and DE CNEPI were obtained. VNEI was reconstructed from CNEPI. Image quality of CNEPI and VNEI was evaluated using a 5-point scale. The attenuation of urine in the bladder on TNEI and VNEI was measured. The CT dose index volume (CTDI (vol)) of the two scans was recorded. Results: The mean image quality score of CNEPI and VNEI was 4.7 and 3.3, respectively. The mean differences in urine attenuation between VNEI and TNEI were 14 {+-} 15 [SD] and -16 {+-} 29 in the anterior and posterior parts of the bladder, respectively. The mean CTDI (vol) for TNEI and CNEPI was 11.8 and 10.9 mGy, respectively. Omission of TNEI could reduce the total radiation dose by 52%. Conclusion: DE split-bolus CTU is technically feasible and can reduce radiation exposure; however, an additional TNEI scan is necessary when the VNEI quality is poor or quantitative evaluation of urine attenuation is required.

  11. 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...

  12. 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...

  13. 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.

  14. An Adaptive Nonlinear Basal-Bolus Calculator for Patients With Type 1 Diabetes.

    Science.gov (United States)

    Boiroux, Dimitri; Aradóttir, Tinna Björk; Nørgaard, Kirsten; Poulsen, Niels Kjølstad; Madsen, Henrik; Jørgensen, John Bagterp

    2017-01-01

    Bolus calculators help patients with type 1 diabetes to mitigate the effect of meals on their blood glucose by administering a large amount of insulin at mealtime. Intraindividual changes in patients physiology and nonlinearity in insulin-glucose dynamics pose a challenge to the accuracy of such calculators. We propose a method based on a continuous-discrete unscented Kalman filter to continuously track the postprandial glucose dynamics and the insulin sensitivity. We augment the Medtronic Virtual Patient (MVP) model to simulate noise-corrupted data from a continuous glucose monitor (CGM). The basal rate is determined by calculating the steady state of the model and is adjusted once a day before breakfast. The bolus size is determined by optimizing the postprandial glucose values based on an estimate of the insulin sensitivity and states, as well as the announced meal size. Following meal announcements, the meal compartment and the meal time constant are estimated, otherwise insulin sensitivity is estimated. We compare the performance of a conventional linear bolus calculator with the proposed bolus calculator. The proposed basal-bolus calculator significantly improves the time spent in glucose target ( P < .01) compared to the conventional bolus calculator. An adaptive nonlinear basal-bolus calculator can efficiently compensate for physiological changes. Further clinical studies will be needed to validate the results.

  15. Bolus matters: the influence of food oral breakdown on dynamic texture perception.

    Science.gov (United States)

    Devezeaux de Lavergne, Marine; van de Velde, Fred; Stieger, Markus

    2017-02-22

    This review article focuses on design of food structure, characterisation of oral processing by boli characterisation and dynamic texture perception. Knowledge of the food properties governing bolus formation and bolus properties determining temporal changes in texture perception is of major importance. Such knowledge allows academia to better understand the mechanisms underlying texture perception and food industry to improve product texture. For instance, such knowledge can be used for developing foods with desired texture perception that fit in a healthy diet or that are customized to specific consumer groups. The end point of oral processing is the formation of a safe-to-swallow bolus. The transitions of solid and soft solid foods into bolus are accompanied by tremendous modifications of food properties. The review discusses dynamic changes in bolus properties resulting in dynamic changes of texture perception during oral processing. Studies monitoring chewing behaviour are discussed to complement the relationships between bolus properties and dynamic texture perception. We conclude that texture perception evolves over mastication time and depends on food properties, such as mechanical properties, mainly in the beginning of oral processing. Towards the middle and end of oral processing, bolus properties depend on food properties and explain texture perception better than food properties.

  16. The modification of specific absorption rates in interstitial microwave hyperthermia via tissue-equivalent material bolus.

    Science.gov (United States)

    Sundararaman, S; Denman, D L; Legorreta, R A; Foster, A E; Redmond, K P; Elson, H R; Born, A M; Samaratunga, R C; Lewis, G C; Kereiakes, J G

    1990-09-01

    Patterns of specific absorption rates generated by interstitial, microwave antenna arrays must be experimentally ascertained and quantified to facilitate their clinical incorporation. Phantom studies involved the use of four single-gap, coaxial antennas oriented in a 2 cm square array. These dipoles were driven in phase by a microwave generator at a frequency of 915 MHz. The inherent limitations in modifying the specific absorption rate patterns were addressed with the addition of bolus to the phantom. These additions of Guy's muscle tissue-equivalent material were made either proximal or distal to the phantom proper. Experiments conducted in the presence and absence of tissue-equivalent material bolus showed the ability to achieve broader bands of 50% power deposition in certain bolus conditions. These heating patterns were sufficiently reproducible and predictable to warrant clinical application of the bolus addition. A through-and-through method of catheter implantation allowed for bolus addition when deemed necessary. Treatments with veterinary and human patients using the bolus method to modify heating patterns yielded augmented patterns of power deposition. The effective length of the antennas that would radiate efficiently was essentially broadened via introduction of a microwave-interacting medium. As a result of the tissue equivalent material's ability to absorb microwave power, it was necessary to interpose minimally-interactive styrofoam spacers to limit heat transfer effects at the tissue-bolus interfaces.

  17. Efficacy study of Styplon Vet Bolus as supportive therapy in management of hemorrhagic conditions of ruminants

    Directory of Open Access Journals (Sweden)

    B R Ravikumar

    Full Text Available On-field trial was conducted in dairy animals to evaluate efficacy of Styplon Vet Bolus (M/s Himalaya Drug Company, Banglore, India as supportive therapy in management of hemorrhagic conditions (Hematuria, hemoagalectia, bleeding wounds, uterine bleeding and epistaxis of ruminants. Styplon Vet 1-2 boli twice daily was administered to cows and buffaloes, and ½ bolus twice daily for sheep till they recover clinically. The results indicated that Styplon Vet Bolus is a safe and effective styptic in ruminants. [Vet World 2009; 2(12.000: 470-471

  18. Utilization of a 3D printer to fabricate boluses used for electron therapy of skin lesions of the eye canthi.

    Science.gov (United States)

    Łukowiak, Magdalena; Jezierska, Karolina; Boehlke, Marek; Więcko, Marzena; Łukowiak, Adam; Podraza, Wojciech; Lewocki, Mirosław; Masojć, Bartłomiej; Falco, Michał

    2017-01-01

    This work describes the use of 3D printing technology to create individualized boluses for patients treated with electron beam therapy for skin lesions of the eye canthi. It aimed to demonstrate the effectiveness of 3D-printed over manually fabricated paraffin boluses. The study involved 11 patients for whom the construction of individual boluses were required. CT scans of the fabricated 3D-printed boluses and paraffin boluses were acquired and superimposed onto patient CT scans to compare their fitting, bolus homogeneity, and underlying dose distribution. To quantify the level of matching, multiple metrics were utilized. Matching Level Index (ML) values ranged from 0 to 100%, where 100% indicated a perfect fit between the reference bolus (planned in treatment planning system) and 3D-printed and paraffin bolus. The average ML (± 1 SD) of the 3D-printed boluses was 95.1 ± 2.1%, compared to 46.0 ± 10.1% for the manually fabricated paraffin bolus. Correspondingly, mean doses were closer to the prescribed doses, and dose spreads were less for the dose distributions from the 3D-printed boluses, as compared to those for the manually fabricated paraffin boluses. It was concluded that 3D-printing technology is a viable method for fabricating boluses for small eye lesions and provides boluses superior to our boluses manually fabricated from paraffin sheets. © 2016 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  19. 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.

  20. Effect of Cerium on the Viscosity of Liquid Fe-C Alloy of Eutectic Content

    Institute of Scientific and Technical Information of China (English)

    滕新营; 叶以富; 刘含莲; 王焕荣; 石志强; 耿浩然

    2002-01-01

    The viscosities of liquid Fe-4.30C and Fe-4.30C-Ce alloys were measured by oscillating crucible viscometer. The results show that viscosity of Fe-4.30C alloy changes from 5.50 to 8.30 MPa*s when the liquid is cooled from 1425 ℃ to the melting point. The abnormity of viscosity of Fe-4.30C alloy near the melting point is reasonable due to the formation of graphite. The addition of cerium especially with content higher than 0.21% causes an evidently decrease in viscosity for eutectic alloy resulting from increase of free volume and size decrease of atom cluster in the liquids. It can be concended that the existence of C-Ce compound contributes to the discontinuous of viscosity at 1340~1370 ℃ for the Fe-4.30C-Ce alloy by experinments with differential scanning calorimeter.

  1. Separate density and viscosity measurements of unknown liquid using quartz crystal microbalance

    Directory of Open Access Journals (Sweden)

    Feng Tan

    2016-09-01

    Full Text Available Aqueous liquids have a wide range of applications in many fields. Basic physical properties like the density and the viscosity have great impacts on the functionalities of a given ionic liquid. For the millions kinds of existing liquids, only a few have been systematically measured with the density and the viscosity using traditional methods. However, these methods are limited to measure the density and the viscosity of an ionic liquid simultaneously especially in processing micro sample volumes. To meet this challenge, we present a new theoretical model and a novel method to separate density and viscosity measurements with single quartz crystal microbalance (QCM in this work. The agreement of experimental results and theocratical calculations shows that the QCM is capable to measure the density and the viscosity of ionic liquids.

  2. Three-dimensional customized bolus for intensity-modulated radiotherapy in a patient with Kimura's disease involving the auricle.

    Science.gov (United States)

    Park, J W; Yea, J W

    2016-05-01

    In radiotherapy, a commercial bolus often does not provide a suitable fit over irregular surfaces. To address this issue, we fabricated a customized bolus using 3D printing technology. The aim of our study was to evaluate the application of this 3D-printed bolus in a clinical setting. The patient was a 45-year-old man with recurrent Kimura's disease involving the auricle, receiving radiotherapy in our oncology department. A customized bolus, 5mm in thickness, was fabricated based on reconstruction of computed tomography (CT) images. The bolus was printed on a Dimension 1200 series SST 3D printer. Repeat CT-based simulation indicated an acceptable fit of the 3D-printed bolus to the target region, with a maximum air gap of less than 5mm at the tragus. Most of the surface area of the target region was covered by the 95% isodose line. The plan with the 3D-printed bolus improved target coverage compared to that without a bolus. And the plan with the 3D-printed bolus yielded comparable results to those with the paraffin wax bolus. In conclusion, a customized bolus using a 3D printer was successfully applied to an irregular surface.

  3. Viscosity affected by nanoparticle aggregation in Al2O3-water nanofluids.

    Science.gov (United States)

    Duan, Fei; Kwek, Dingtian; Crivoi, Alexandru

    2011-03-22

    An investigation on viscosity was conducted 2 weeks after the Al2O3-water nanofluids having dispersants were prepared at the volume concentration of 1-5%. The shear stress was observed with a non-Newtonian behavior. On further ultrasonic agitation treatment, the nanofluids resumed as a Newtonian fluids. The relative viscosity increases as the volume concentrations increases. At 5% volume concentration, an increment was about 60% in the re-ultrasonication nanofluids in comparison with the base fluid. The microstructure analysis indicates that a higher nanoparticle aggregation had been observed in the nanofluids before re-ultrasonication.

  4. 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.

  5. The viscosity of dimethyl ether

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Jakobsen, Jørgen

    2007-01-01

    Dimethyl ether (DME) has been recognised as an excellent fuel for diesel engines for over one decade now. Engines fuelled by DME emit virtually no particulate matter even at low NOx levels. This is only possible in the case of diesel oil operation if expensive and efficient lowering particles...... for pressurisation in these methods. The results of the VFVM are consolidated by measurements of the viscosities of propane and butane: these agree with the outcome of measurements using a quartz crystal microbalance (QCM) a method that is supposedly less sensible than the Reynolds number....

  6. 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.)

  7. 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.

  8. Prolonged Administration of Twice-Daily Bolus Intravenous Tacrolimus in the Early Phase After Lung Transplantation.

    Science.gov (United States)

    Hirano, Yutaka; Sugimoto, Seiichiro; Mano, Toshifumi; Kurosaki, Takeshi; Miyoshi, Kentaroh; Otani, Shinji; Yamane, Masaomi; Kobayashi, Motomu; Miyoshi, Shinichiro; Oto, Takahiro

    2017-08-11

    BACKGROUND Although administration of tacrolimus, whether by the enteric, sublingual, or continuous intravenous routes, has some limitations, twice-daily bolus intravenous tacrolimus administration has been shown to be beneficial in optimizing efficacy and safety after lung transplantation. However, at present, the duration of bolus intravenous tacrolimus administration is limited, and the effects of prolonged bolus intravenous tacrolimus administration remain unknown. Our study was aimed at assessing the safety and efficacy of prolonged twice-daily bolus intravenous tacrolimus administration in the early phase after lung transplantation. MATERIAL AND METHODS We retrospectively investigated the data of 62 recipients of lung transplantation who had received twice-daily bolus intravenous administration of tacrolimus, followed by oral tacrolimus, after lung transplantation at our institution between January 2011 and October 2015. RESULTS The median duration of bolus intravenous tacrolimus administration was 19 days (4-72 days). The target trough level was achieved in 89% of the patients by day 3. Acute kidney injury occurred in 27% of the patients during bolus intravenous tacrolimus. Two patients (3%) had neurotoxicity, necessitating discontinuation of tacrolimus. Suspected acute rejection requiring steroid pulse therapy occurred in 21% of patients during the follow-up period. Eight patients (13%) developed chronic lung allograft dysfunction during the follow-up period. The 1-year and 5-year survival rates after lung transplantation were 95% and 76%, respectively. CONCLUSIONS These results suggest that prolonged bolus intravenous tacrolimus administration in the early phase after lung transplantation is a safe and effective alternative to enteric, sublingual, or continuous intravenous administration.

  9. Potential of 3D printing technologies for fabrication of electron bolus and proton compensators.

    Science.gov (United States)

    Zou, Wei; Fisher, Ted; Zhang, Miao; Kim, Leonard; Chen, Ting; Narra, Venkat; Swann, Beth; Singh, Rachana; Siderit, Richard; Yin, Lingshu; Teo, Boon-Keng Kevin; McKenna, Michael; McDonough, James; Ning, Yue J

    2015-05-08

    In electron and proton radiotherapy, applications of patient-specific electron bolus or proton compensators during radiation treatments are often necessary to accommodate patient body surface irregularities, tissue inhomogeneity, and variations in PTV depths to achieve desired dose distributions. Emerging 3D printing technologies provide alternative fabrication methods for these bolus and compensators. This study investigated the potential of utilizing 3D printing technologies for the fabrication of the electron bolus and proton compensators. Two printing technologies, fused deposition modeling (FDM) and selective laser sintering (SLS), and two printing materials, PLA and polyamide, were investigated. Samples were printed and characterized with CT scan and under electron and proton beams. In addition, a software package was developed to convert electron bolus and proton compensator designs to printable Standard Tessellation Language file format. A phantom scalp electron bolus was printed with FDM technology with PLA material. The HU of the printed electron bolus was 106.5 ± 15.2. A prostate patient proton compensator was printed with SLS technology and polyamide material with -70.1 ± 8.1 HU. The profiles of the electron bolus and proton compensator were compared with the original designs. The average over all the CT slices of the largest Euclidean distance between the design and the fabricated bolus on each CT slice was found to be 0.84 ± 0.45 mm and for the compensator to be 0.40 ± 0.42 mm. It is recommended that the properties of specific 3D printed objects are understood before being applied to radiotherapy treatments.

  10. Excess Molar Volumes and Viscosities of Binary Mixtures of p-Xylene with Cyclohexane, n-Heptane, n-Octane,Sulfolane, N-Methyl-2-pyrrolidone and Acetic Acid at 303.15 K and 323.15 K and Atmospheric Pressure%对二甲苯与环己烷、正庚烷、正辛烷、环丁砜和N-甲基-2-吡咯烷酮和乙酸二元混合物在303.15K和323.15K的 超额体积和黏度

    Institute of Scientific and Technical Information of China (English)

    杨长生; 马沛生; 周清

    2004-01-01

    Experimental data on density and viscosity at 303.15K and 323.15K are presented for the binary mixtures of p-xylene with cyclohexane, n-heptane, n-octane, sulfolane, N-methyl-2-pyrrolidone and acetic acid.From these data, the excess molar volume and deviations in viscosity have been calculated. The computed quantities have been fitted to the Redlich-Kister Equation to derive coefficients and estimate the standard error values. Results are discussed in terms of intermolecular interactions.

  11. Double Bolus Application in TWIST-MR-Angiography of the Cervical Arteries

    Directory of Open Access Journals (Sweden)

    Andreas Korn

    2012-01-01

    Full Text Available Purpose. The aim of the present work was to test the feasibility of the time-resolved MR-angiography (TWIST-MRA of cervical arteries using double bolus injection. Material and Methods. TWIST-MRA with a temporal resolution of 8.4 seconds for each frame and a spatial resolution with a voxel size of   was performed in 24 patients. A biphasic bolus injection protocol was used with the second injection being started 21 seconds after the first contrast dye bolus. Diagnostic image quality was rated according to a 4-point scale. Results. In 12 patients (50% no clear separation between the cervical venous and arterial vessels was evident after the first bolus injection. Using TWIST-MRA data acquired after the second bolus a sufficient diagnostic image quality (rating , mean 3.5 could be obtained in 22 of 24 patients (92%. Discussion. The double bolus injection protocol using TWIST-MRA allows for very good separation of the cervical arteries.

  12. The interrelationship between bolus breakdown, mandibular first molar displacement and jaw movement during mastication.

    Science.gov (United States)

    Yomoda, S; Hisano, M; Amemiya, K; Soma, K

    2004-02-01

    The purpose of this study was to clarify the interrelationship between food bolus breakdown, mandibular first molar displacement and jaw movement during mastication. Finite element models were constructed of the maxillary first molar crown, the mandibular first molar consisting of crown, root, periodontal ligament and alveolar bone, as well as the food bolus were constructed. Based on the actual measurement of the jaw movement pattern and the characteristics of food bolus, the patterns of mandibular first molar displacement and bolus breakdown on time course in the progress of mastication were simulated, to investigate the biomechanical significance of tooth displacement and jaw movement during mastication, using finite element non-linear dynamic analysis. The results showed that the patterns of tooth displacement and jaw movement and characteristics of food bolus changed with an interrelationship to each other as mastication progressed. Particularly at the initial phase, it was suggested that the patterns of mandibular first molar displacement and jaw movement worked inter-dependently to accomplish an efficient hard-bolus breakdown.

  13. Pressure Flow Analysis in the Assessment of Preswallow Pharyngeal Bolus Presence in Dysphagia

    Directory of Open Access Journals (Sweden)

    Lara Ferris

    2015-01-01

    Full Text Available Objectives. Preswallow pharyngeal bolus presence is evident in patients with oropharyngeal dysphagia. Pressure flow analysis (PFA using high resolution manometry with impedance (HRMI with AIMplot software is a method for objective interpretation of pharyngeal and upper esophageal sphincter (UES pressures and bolus flow patterns during swallowing. This study aimed to observe alterations in PFA metrics in the event of preswallow pharyngeal bolus presence as seen on videofluoroscopy (VFSS. Methods. Swallows from 40 broad dysphagia patients and 8 controls were recorded with a HRMI catheter during simultaneous VFSS. Evidence of bolus presence and level reached prior to pharyngeal swallow onset was recorded. AIMPlot software derived automated PFA functional metrics. Results. Patients with bolus movement to the pyriform sinuses had a higher SRI, indicating greater swallow dysfunction. Amongst individual metrics, TNadImp to PeakP was shorter and flow interval longer in patient groups compared to controls. A higher pharyngeal mean impedance and UES mean impedance differentiated the two patient groups. Conclusions. This pilot study identifies specific altered PFA metrics in patients demonstrating preswallow pharyngeal bolus presence to the pyriform sinuses. PFA metrics may be used to guide diagnosis and treatment of patients with oropharyngeal dysphagia and track changes in swallow function over time.

  14. 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.

  15. 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.

  16. Shear time dependent viscosity of polystyrene-ethylacrylate based shear thickening fluid

    Science.gov (United States)

    Chen, Qian; Xuan, Shouhu; Jiang, Wanquan; Cao, Saisai; Gong, Xinglong

    2016-04-01

    In this study, the influence of the shear rate and shear time on the transient viscosity of polystyrene-ethylacrylate based shear thickening fluid (STF) is investigated. If the shear rate is stepwise changed, it is found that both the viscosity and critical shear rate are affected by the shear time. Above the critical shear rate, the viscosity of the STF with larger power law exponent (n) increases faster. However, the viscosity tends to decrease when the shear time is long enough. This phenomenon can be responsible for the reversible structure buildup and the break-down process. An effective volume fraction (EVF) mechanism is proposed to analyze the shear time dependent viscosity and it is found that viscosity changes in proportion to EVF. To further clarify the structure evolution, a structural kinetic model is studied because the structural kinetic parameter (λ) could describe the variation in the effective volume fraction. The theoretical results of the structural kinetic model agree well with the experimental results. With this model, the change in viscosity and EVF can be speculated from the variation of λ and then the structure evolution can be better illustrated.

  17. Experimental study on viscosity of spinel-type manganese ferrite nanofluid in attendance of magnetic field

    Science.gov (United States)

    Amani, Mohammad; Amani, Pouria; Kasaeian, Alibakhsh; Mahian, Omid; Kasaeian, Fazel; Wongwises, Somchai

    2017-04-01

    In this paper, an experimental evaluation on the viscosity of water-based manganese ferrite nanofluid with and without magnetic field with 100, 200, 300, and 400 G intensities has been conducted. The Brookfield DV-I PRIME viscometer is implemented to measure the MnFe2O4/water nanofluid viscosity and to evaluate the influence of different volume concentrations (from 0.25% to 3%) and various temperatures (from 20 to 60 °C) on the viscosity. According to the measurements, viscosity incrementally increases with the augmentation of nanoparticles concentration while it remarkably decreases at higher temperatures under absence and attendance of magnetic field. The maximum viscosity ratio of 1.14 is achieved at 3 vol% of nanoparticles and 20 °C under no magnetic field, whereas it increments to maximum viscosity ratio of 1.75 at 3 vol% of nanoparticles and 40 °C under 400 G magnetic field. Furthermore, new correlation is proposed for determination of viscosity of MnFe2O4/water nanofluids in terms of magnetic field intensity, volume concentration and temperature.

  18. 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.

  19. Field induced rotational viscosity of ferrofluid: effect of capillary size and magnetic field direction.

    Science.gov (United States)

    Andhariya, Nidhi; Chudasama, Bhupendra; Patel, Rajesh; Upadhyay, R V; Mehta, R V

    2008-07-01

    In the present investigation we report the effect of capillary diameter and the direction of applied magnetic field on the rotational viscosity of water and kerosene based ferrofluids. We found that changes in the field induced rotational viscosity are larger in the case of water based magnetic fluid than that of kerosene based fluid. The field induced rotational viscosity is found to be inversely proportional to the capillary diameter and it falls exponentially as a function of the angle between the direction of field and vorticity of flow. Magnetophoretic mobility and hydrodynamic volume fraction of nanomagnetic particles are determined for above cases.

  20. Evaluation of the Eclipse eMC algorithm for bolus electron conformal therapy using a standard verification dataset.

    Science.gov (United States)

    Carver, Robert L; Sprunger, Conrad P; Hogstrom, Kenneth R; Popple, Richard A; Antolak, John A

    2016-05-08

     The purpose of this study was to evaluate the accuracy and calculation speed of electron dose distributions calculated by the Eclipse electron Monte Carlo (eMC) algorithm for use with bolus electron conformal therapy (ECT). The recent com-mercial availability of bolus ECT technology requires further validation of the eMC dose calculation algorithm. eMC-calculated electron dose distributions for bolus ECT have been compared to previously measured TLD-dose points throughout patient-based cylindrical phantoms (retromolar trigone and nose), whose axial cross sections were based on the mid-PTV (planning treatment volume) CT anatomy. The phantoms consisted of SR4 muscle substitute, SR4 bone substitute, and air. The treatment plans were imported into the Eclipse treatment planning system, and electron dose distributions calculated using 1% and eMC-calculated less measured dose) were evaluated in terms of absolute dose difference, where 100% equals the given dose, as well as distance to agreement (DTA). Dose calculations were also evaluated for calculation speed. Results from the eMC for the retromolar trigone phantom using 1% statistical uncertainty without smoothing showed calculated dose at 89% (41/46) of the measured TLD-dose points was within 3% dose difference or 3 mm DTA of the measured value. The average dose difference was -0.21%, and the net standard deviation was 2.32%. Differences as large as 3.7% occurred immediately distal to the mandible bone. Results for the nose phantom, using 1% statistical uncertainty without smoothing, showed calculated dose at 93% (53/57) of the measured TLD-dose points within 3% dose difference or 3 mm DTA. The average dose difference was 1.08%, and the net standard deviation was 3.17%. Differences as large as 10% occurred lateral to the nasal air cavities. Including smoothing had insignificant effects on the accuracy of the retromolar trigone phantom calculations, but reduced the accuracy of the nose phantom calculations in the

  1. Evaluation of the Eclipse eMC algorithm for bolus electron conformal therapy using a standard verification dataset.

    Science.gov (United States)

    Carver, Robert L; Sprunger, Conrad P; Hogstrom, Kenneth R; Popple, Richard A; Antolak, John A

    2016-05-01

    The purpose of this study was to evaluate the accuracy and calculation speed of electron dose distributions calculated by the Eclipse electron Monte Carlo (eMC) algorithm for use with bolus electron conformal therapy (ECT). The recent commercial availability of bolus ECT technology requires further validation of the eMC dose calculation algorithm. eMC-calculated electron dose distributions for bolus ECT have been compared to previously measured TLD-dose points throughout patient-based cylindrical phantoms (retromolar trigone and nose), whose axial cross sections were based on the mid-PTV (planning treatment volume) CT anatomy. The phantoms consisted of SR4 muscle substitute, SR4 bone substitute, and air. The treatment plans were imported into the Eclipse treatment planning system, and electron dose distributions calculated using 1% and <0.2% statistical uncertainties. The accuracy of the dose calculations using moderate smoothing and no smoothing were evaluated. Dose differences (eMC-calculated less measured dose) were evaluated in terms of absolute dose difference, where 100% equals the given dose, as well as distance to agreement (DTA). Dose calculations were also evaluated for calculation speed. Results from the eMC for the retromolar trigone phantom using 1% statistical uncertainty without smoothing showed calculated dose at 89% (41/46) of the measured TLD-dose points was within 3% dose difference or 3 mm DTA of the measured value. The average dose difference was -0.21%, and the net standard deviation was 2.32%. Differences as large as 3.7% occurred immediately distal to the mandible bone. Results for the nose phantom, using 1% statistical uncertainty without smoothing, showed calculated dose at 93% (53/57) of the measured TLD-dose points within 3% dose difference or 3 mm DTA. The average dose difference was 1.08%, and the net standard deviation was 3.17%. Differences as large as 10% occurred lateral to the nasal air cavities. Including smoothing had

  2. 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.

  3. A Study on the Necessary Number of Bolus Treatments in Radiotherapy after Modified Radical Mastectomy

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Chae Seon; Kim, Jong Sik; Kim, Young Kon; Park, Young Hwan [Dept. of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2006-09-15

    Post-mastectomy radiotherapy (PMR) is known to decrease loco-regional recurrence. Adequate skin and dermal dose are achieved by adding bolus. The more difficult clinical issue is determining the necessary number of bolus treatment, given the limits of normal skin tolerance. The aim of this study is to evaluate the necessary number of bolus treatment after PMR in patients with breast cancer. Four female breast cancer patients were included in the study. The median age was 53 years(range, 38-74), tumor were left sided in 2 patients and right sided in 2 patients. All patients were treated with postoperative radiotherapy after MRM. Radiotherapy was delivered to the chest wall (C.W) and supraclavicular lymph nodes (SCL) using 4 MV X-ray. The total dose was 50 Gy, in 2 Gy fractions (with 5 times a week). CT was performed for treatment planning, treatment planning was performed using A DAC-Pinnacles{sup 3} (Phillips, USA) for all patients without and with bolus. Bolus treatment plans were generated using image tool (0.5 cm of thickness and 6 cm of width). Dose distribution was analyzed and the increased skin dose rate in the build-up region was computed and the skin dose using TLD-100 chips (Harshaw, USA) was measured. No significant difference was found in dose distribution without and with bolus; C.W coverage was 95-100% of the prescribed dose in both. But, there was remarkable difference in the skin dose to the scar. The skin dose to the scar without and with bolus were 100-105% and 50-75%. The increased skin dose rates in the build-up region for Pt. 1, Pt. 2. Pt. 3 and Pt. 4 were 23.3%, 35.6%, 34.9%, and 41.7%. The results of measured skin dose using TLD-100 chips in the cases without and with bolus were 209.3 cGy and 161.1 cGy, 200 cGy and 150.2 cGy, 211.4 cGy and 160.5 cGy, 198.6 cGy and 155.5 cGy for Pt. 1, Pt. 2, Pt. 3, and Pt. 4. It was concludes through this analysis that the adequate number of bolus treatments is 50-60% of the treatment program. Further

  4. How the dispersion of magnesium oxide nanoparticles effects on the viscosity of water-ethylene glycol mixture: Experimental evaluation and correlation development

    Science.gov (United States)

    Afrand, Masoud; Abedini, Ehsan; Teimouri, Hamid

    2017-03-01

    In this paper, the effect of dispersion of magnesium oxide nanoparticles on viscosity of a mixture of water and ethylene glycol (50-50% vol.) was examined experimentally. Experiments were performed for various nanofluid samples at different temperatures and shear rates. Measurements revealed that the nanofluid samples with volume fractions of less than 1.5% had Newtonian behavior, while the sample with volume fraction of 3% showed non-Newtonian behavior. Results showed that the viscosity of nanofluids enhanced with increasing nanoparticles volume fraction and decreasing temperature. Results of sensitivity analysis revealed that the viscosity sensitivity of nanofluid samples to temperature at higher volume fractions is more than that of at lower volume fractions. Finally, because of the inability of the existing model to predict the viscosity of MgO/EG-water nanofluid, an experimental correlation has been proposed for predicting the viscosity of the nanofluid.

  5. 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. 

  6. 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.

  7. 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...

  8. 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

  9. Hyperon bulk viscosity in strong magnetic fields

    CERN Document Server

    Sinha, Monika

    2008-01-01

    We study bulk viscosity in neutron star matter including $\\Lambda$ hyperons in the presence of quantizing magnetic fields. Relaxation time and bulk viscosity due to both the non-leptonic weak process involving $\\Lambda$ hyperons and the direct Urca (dUrca) process are calculated here. In the presence of a strong magnetic field, bulk viscosity coefficients are enhanced when protons, electrons and muons are populated in their respective zeroth Landau levels compared with the field free cases. The enhancement of bulk viscosity coefficient is larger for the dUrca case.

  10. 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.

  11. Viscosity of oil and water mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Corlett, A.E.; Hall, A.R.W. [National Engineering Laboratory, Glasgow (United Kingdom)

    1999-07-01

    A study was performed to investigate the apparent viscosity of oil and water mixtures using the pressure loss along a horizontal pipe. Water fractions between 100% to 5% were examined at three flow velocities and three temperatures. Four combinations of crude oil and saline solution were used. Tests found that the mixture viscosity exhibited a peak at the position of phase inversion. The value of this maximum viscosity depended upon the temperature and fluid combination used, but not the velocity. Physical properties of the fluids were important factors in the viscosity/water fraction behaviour. (author)

  12. High Resolution Viscosity Measurement by Thermal Noise Detection

    Directory of Open Access Journals (Sweden)

    Felipe Aguilar Sandoval

    2015-11-01

    Full Text Available An interferometric method is implemented in order to accurately assess the thermal fluctuations of a micro-cantilever sensor in liquid environments. The power spectrum density (PSD of thermal fluctuations together with Sader’s model of the cantilever allow for the indirect measurement of the liquid viscosity with good accuracy. The good quality of the deflection signal and the characteristic low noise of the instrument allow for the detection and corrections of drawbacks due to both the cantilever shape irregularities and the uncertainties on the position of the laser spot at the fluctuating end of the cantilever. Variation of viscosity below 0.03 mPa·s was detected with the alternative to achieve measurements with a volume as low as 50 µL.

  13. Magnetic microparticle aggregation for viscosity determination by MR.

    Science.gov (United States)

    Hong, Rui; Cima, Michael J; Weissleder, Ralph; Josephson, Lee

    2008-03-01

    Micron-sized magnetic particles were induced to aggregate when placed in homogeneous magnetic fields, like those of MR imagers and relaxometers, and then spontaneously returned to their dispersed state when removed from the field. Associated with the aggregation and dispersion of the magnetic particles were time-dependent increases and decreases in the spin-spin relaxation time (T2) of the water. Magnetic nanoparticles, with far smaller magnetic moments per particle, did not undergo magnetically induced aggregation and exhibited time-independent values of T2. The rate of T2 change associated with magnetic microparticle aggregation was used to determine the viscosity of liquid samples, providing a method that can be of particular advantage for determining the viscosity of small volumes of potentially biohazardous samples of blood or blood plasma. (c) 2008 Wiley-Liss, Inc.

  14. Magnetic Microparticle Aggregation For Viscosity Determination By Magnetic Resonance

    Science.gov (United States)

    Hong, Rui; Cima, Michael J.; Weissleder, Ralph; Josephson, Lee

    2009-01-01

    Micron-sized magnetic particles were induced to aggregate when placed in homogeneous magnetic fields, like those of magnetic resonance (MR) imagers and relaxometers, and then spontaneously returned to their dispersed state when removed from the field. Associated with the aggregation and dispersion of the magnetic particles were time dependent increases and decreases in the spin-spin relaxation time (T2) of the water. Magnetic nanoparticles, with far smaller magnetic moments per particle, did not undergo magnetically induced aggregation, and exhibited time independent values of T2. The rate of T2 change associated with magnetic micro-particle aggregation was used to determine the viscosity of liquid samples, providing a method that can be of particular advantage for determining the viscosity of small volumes of potentially biohazardous samples of blood or blood plasma. PMID:18306403

  15. Experiment and Artificial Neural Network Prediction of Thermal Conductivity and Viscosity for Alumina-Water Nanofluids.

    Science.gov (United States)

    Zhao, Ningbo; Li, Zhiming

    2017-05-19

    To effectively predict the thermal conductivity and viscosity of alumina (Al₂O₃)-water nanofluids, an artificial neural network (ANN) approach was investigated in the present study. Firstly, using a two-step method, four Al₂O₃-water nanofluids were prepared respectively by dispersing different volume fractions (1.31%, 2.72%, 4.25%, and 5.92%) of nanoparticles with the average diameter of 30 nm. On this basis, the thermal conductivity and viscosity of the above nanofluids were analyzed experimentally under various temperatures ranging from 296 to 313 K. Then a radial basis function (RBF) neural network was constructed to predict the thermal conductivity and viscosity of Al₂O₃-water nanofluids as a function of nanoparticle volume fraction and temperature. The experimental results showed that both nanoparticle volume fraction and temperature could enhance the thermal conductivity of Al₂O₃-water nanofluids. However, the viscosity only depended strongly on Al₂O₃ nanoparticle volume fraction and was increased slightly by changing temperature. In addition, the comparative analysis revealed that the RBF neural network had an excellent ability to predict the thermal conductivity and viscosity of Al₂O₃-water nanofluids with the mean absolute percent errors of 0.5177% and 0.5618%, respectively. This demonstrated that the ANN provided an effective way to predict the thermophysical properties of nanofluids with limited experimental data.

  16. Excess molar volumes and viscosities for binary mixtures of 3-heptanone + ethyl acetate, 3-heptanone + butyl acetate, 3-heptanone + tributyl phosphate,and methyl isobutyl ketone + tributyl phosphate%3-庚酮+乙酸乙酯、3-庚酮+乙酸丁酯、3-庚酮+TBP、MIBK+ TBP二元体系的过量摩尔体积和黏度

    Institute of Scientific and Technical Information of China (English)

    杨得岭; 林晓; 曹宏斌; 李以圭; 张懿

    2012-01-01

    Densities and viscosities of four binary mixtures of 3-heptanone + ethyl acetate, 3-heptanone + butyl acetate, 3-heptanone + tributyl phosphate and methyl isobutyl ketone + tributyl phosphate were determined from 293. 15 K to 318. 15 K under atmospheric pressure using Anton Paar DMA5000 vibrating-tube densimeter and Anton Paar AMVn automated micro viscometer. From the experimental data of density and viscosity, the excess molar volumes VE and viscosity deviation △η were calculated and correlated with the Redlich-Kister polynomial equation. The viscosities of the mixtures were correlated by Orrick-Erbar (OE) group-contribution method. And the new group-contribution parameters A and B for (-O)3-P=O group were obtained. The results show that the improved Orrick-Erbar equation is able to predict the viscosities for mixtures from their pure solvents and the deviation is acceptable in engineering applications.%常压下测定了3-庚酮+乙酸乙酯、3-庚酮+乙酸丁酯、3-庚酮+磷酸三丁酯(TBP)、4-甲基-2-戊酮(MI-BK)+磷酸三丁酯4个二元体系在293.15~318.15 K下的密度和黏度值,计算了二元体系的过量摩尔体积VE和过量黏度△η,并用Redlich-Kister方程对VE和△η进行了关联.混合溶剂的黏度数据采用Orrick-Erbar(O-E)基团贡献法进行了关联和预测,增加了O-E方法中的(-O)3-P=O基团贡献值.结果表明,O-E方法可根据现有的纯溶剂的黏度数据预测得到混合溶剂的黏度,平均误差小于15%.

  17. Glucagon Is a Safe and Inexpensive Initial Strategy in Esophageal Food Bolus Impaction.

    Science.gov (United States)

    Haas, Jason; Leo, Julia; Vakil, Nimish

    2016-03-01

    Controversy exists about the utility of pharmacologic agents and endoscopic technique used for esophageal food bolus impaction. To evaluate the utility of glucagon and the technique used for endoscopic removal, including the rate of success and the adverse events of the techniques. The database of the largest healthcare provider in southeastern Wisconsin was retrospectively reviewed for patients presenting with esophageal food bolus impaction. Data extracted included glucagon administration and its success rate, outcome of radiographic studies, and the endoscopic method of removal and adverse events associated with it, including 30-day mortality. A total of 750 patients were identified with food bolus impaction from 2007 to 2012. Glucagon was administered in 440 patients and was successful in 174 (39.5%). Endoscopic removal was performed in 470 patients and was successful in 469 (99.8%). The push technique was utilized in 209 patients, reduction in the bolus size by piecemeal removal followed by the push technique was utilized in 97 patients, and the pull technique was utilized in 107 patients. There were no perforations with endoscopic removal. Only 4.5% of the X-rays performed reported a possible foreign body within the esophagus. Glucagon was a significantly less-expensive strategy than endoscopic therapy (p low cost, is moderately effective, and may be considered as an initial strategy. Endoscopic removal regardless of technique is safe and effective. The yield of radiography is poor in the setting of food bolus impaction.

  18. Flow patterns and heat convection in a rectangular water bolus for use in superficial hyperthermia.

    Science.gov (United States)

    Birkelund, Yngve; Jacobsen, Svein; Arunachalam, Kavitha; Maccarini, Paolo; Stauffer, Paul R

    2009-07-07

    This paper investigates both numerically and experimentally the spatio-temporal effects of water flow in a custom-made water bolus used for superficial hyperthermia generated by a 915-MHz, 4 x 3 microwave applicator array. Similar hyperthermia models referenced in the literature use a constant water temperature and uniform heat flux to describe conduction and convection energy exchange within the heating apparatus available to cool the tissue surface. The results presented in this paper show that the spatially varying flow pattern and rate are vital factors for the overall heat control applicability of the 5 mm thick bolus under study. Regions with low flow rates and low heat convection clearly put restrictions on the maximum microwave energy possible within the limits of skin temperature rise under the bolus. Our analysis is illustrated by experimental flow front studies using a contrast liquid set-up monitored by high definition video and complemented by numerical analysis of liquid flow and heat exchange within the rectangular water bolus loaded by malignant tissue. Important factors for the improvement of future bolus designs are also discussed in terms of diameter and configuration of the water input and output tubing network.

  19. Endoleak detection using single-acquisition split-bolus dual-energy computer tomography (DECT)

    Energy Technology Data Exchange (ETDEWEB)

    Javor, D.; Wressnegger, A.; Unterhumer, S.; Kollndorfer, K.; Nolz, R.; Beitzke, D.; Loewe, C. [Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Vienna (Austria)

    2017-04-15

    To assess a single-phase, dual-energy computed tomography (DECT) with a split-bolus technique and reconstruction of virtual non-enhanced images for the detection of endoleaks after endovascular aneurysm repair (EVAR). Fifty patients referred for routine follow-up post-EVAR CT and a history of at least one post-EVAR follow-up CT examination using our standard biphasic (arterial and venous phase) routine protocol (which was used as the reference standard) were included in this prospective trial. An in-patient comparison and an analysis of the split-bolus protocol and the previously used double-phase protocol were performed with regard to differences in diagnostic accuracy, radiation dose, and image quality. The analysis showed a significant reduction of radiation dose of up to 42 %, using the single-acquisition split-bolus protocol, while maintaining a comparable diagnostic accuracy (primary endoleak detection rate of 96 %). Image quality between the two protocols was comparable and only slightly inferior for the split-bolus scan (2.5 vs. 2.4). Using the single-acquisition, split-bolus approach allows for a significant dose reduction while maintaining high image quality, resulting in effective endoleak identification. (orig.)

  20. Reducing blood viscosity with magnetic fields.

    Science.gov (United States)

    Tao, R; Huang, K

    2011-07-01

    Blood viscosity is a major factor in heart disease. When blood viscosity increases, it damages blood vessels and increases the risk of heart attacks. Currently, the only method of treatment is to take drugs such as aspirin, which has, however, several unwanted side effects. Here we report our finding that blood viscosity can be reduced with magnetic fields of 1 T or above in the blood flow direction. One magnetic field pulse of 1.3 T lasting ~1 min can reduce the blood viscosity by 20%-30%. After the exposure, in the absence of magnetic field, the blood viscosity slowly moves up, but takes a couple of hours to return to the original value. The process is repeatable. Reapplying the magnetic field reduces the blood viscosity again. By selecting the magnetic field strength and duration, we can keep the blood viscosity within the normal range. In addition, such viscosity reduction does not affect the red blood cells' normal function. This technology has much potential for physical therapy.

  1. 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...

  2. 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.

  3. Comparison of Bolus Phenylephrine, Ephedrine and Mephentermine for Maintenance of Arterial Pressure during Spinal Anesth

    Directory of Open Access Journals (Sweden)

    B Bhattarai

    2010-03-01

    Full Text Available INTRODUCTION: Hypotension is common following spinal anesthesia. Various vasopressors have been indicated to prevent it. The study compares three such agents namely phenylephrine, ephedrine and mephentermine. METHODS: The study included 90 patients undergoing elective and emergency cesarean section who developed hypotension following subarachnoid blockade. Parturient were randomly divided into three groups each group had 30 patients. Group P received bolus of Phenylephrine 25 microgram, where as group E received Ephedrine 5mg and Group M received Mephentermine 6mg. RESULTS: It was found that rise of blood pressure was significantly higher in case of phenylephrine group in first six minutes, after the bolus, there was significant reduction in the heart rate in phenylephrine group, but there was tachycardia following administration of bolus ephedrine and mephenteramine. Neonatal APGAR score were similar in all three groups. CONCLUSIONS: All three drugs maintained hemodynamics within 20 percent of the baseline values on intravenous administration. Keywords: APGAR, ephedrine, hypotension, mephentermine, phenylephrine, spinal anesthesia.

  4. The Effect of Variable Viscosities on Micropolar Flow of Two Nanofluids

    Science.gov (United States)

    Nadeem, S.; Ahmed, Z.; Saleem, S.

    2016-12-01

    A study of nanofluids is carried out that reveals the effect of rotational inertia and other physical parameters on the heat transfer and fluid flow. Temperature-dependent dynamic viscosity makes the microrotation viscosity parameter and the micro inertia density variant as well. The governing nonlinear partial differential equations are converted into a set of nonlinear ordinary differential equations by introducing suitable similarity transformations. These reduced nonlinear differential equations are then solved numerically by Keller-box method. The obtained numerical and graphical result discloses many interesting behaviour of nanofluids. It is seen that the temperature gradient decreases with the increase in viscosity parameter. Also, it is observed that with the fixed values of micropolar parameter and viscosity parameter, the velocity gradient near the wall increases with increasing values of solid particle volume fraction parameter. A suitable comparison of results is also presented in this study.

  5. The Consideration of Bolus Effects of Games Attached on Lesion area

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ju Young; Ju, Sang Kyu; Park, Young Chul; Han, Young Yi; Shin, Eun Hyuk; Park, Yong Hwan [Dept. of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2004-03-15

    The aim of this study is to evaluate the effect of skin dose and PDD by using wounds protecting gauzes or Vaselinespread gauzes. And it was studied that the possibility to substitute custom bolus into gauzes. 4 MV photon (CL600C, varian, US), Polystyrene Phantom (30(W) X 30(L) X 30(H)) with Markus chamber(PTW, US) were used for dose measurement. This study was distinguished natural gauzes and spread over Vaseline gauzes. We gave variety to the gauze thickness at 5, 10 and 15 sheets respectively. For comparison between using bolus and not that, we had used 1.0 cm thickness bolus so that analyzed surface dose and PDD at the same conditions above mentioned. When maximum point was defined as reference point, surface dose was measured as 35% in open beam. When the gauzes were attached to surface as 5, 10 and 15 sheets, surface dose were increased as 69, 80 and 91% respectively according to thickness of gauzes. When spread over Vaseline gauzes were attached to surface as 5, 10 and 15 sheets, surface dose were increased respectively as 98, 100 and 98% according to thickness of gauzes. Also when 0.5 cm bolus and 5 sheets gauzes were composed, surface dose was measured as 98%. The gauzes that were attached to skin surface in radiation therapy had been scattering material and contributed increasing surface dose without variation of percentage depth dose. However, if we want to delivery much dose to skin surface then we have to apply many sheets of gauzes to skin surface. Although we get easy that result by bolus or spread over Vaseline gauzes, we have to revise percentage depth dose at calculation. Therefore, if we find pertinent conditions based on measured data that are considered skin dose and patient setup efficiency, to replace custom bolus with gauzes will be helpful to efficient treatment.

  6. 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.

  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. Comparison of Insulin Detemir and Insulin Glargine for Hospitalized Patients on a Basal-Bolus Protocol

    Directory of Open Access Journals (Sweden)

    Sondra Davis

    2017-04-01

    Full Text Available BACKGROUND: The primary purpose of this study is to determine whether insulin detemir is equivalent to insulin glargine in controlling hyperglycemia for the adult hospitalized patient on a basal-bolus treatment regimen. METHODS: A retrospective study was conducted at two acute care hospitals within the same health system. Patients from both facilities who were initiated on a basal-bolus subcutaneous insulin regimen were included in the study. The basal-bolus regimen consisted of three components: basal, bolus, and corrective insulin with only the data from the first seven days analyzed. Once the basal-bolus protocol was initiated, all previous glycemic agents were discontinued. The target glycemic goal of the study was 100–180 mg/dL. RESULTS: In both groups, 50% of the patients had achieved the target glycemic control goal (100–180 mg/dL by day 2 (p = 0.3. However, on the seventh or last day of basal-bolus treatment, whichever came first, 36.36% of patients receiving insulin detemir (n = 88 achieved the blood glucose reading goal compared to 52.00% in patients receiving insulin glargine (n = 100 (p = 0.03. This corresponded to an adjusted odds ratio of 2.12 (1.08 to 4.15, p = 0.03. The adjusting variables were provider type, whether the patient was hospitalized within 30 days prior and diagnosis of stroke. The mean blood glucose readings for the insulin glargine and the insulin detemir groups while on basal-bolus therapy were 200 mg/dL and 215 mg/dL, respectively (p = 0.05. The total number of blood glucose readings less than 70 mg/dL and less than 45 mg/dL was very low and there were no differences in number of episodes with hypoglycemia between the two groups. CONCLUSION: There was not a statistical difference between the two groups at 2 days, however there was on the seventh day or the last day of basal-bolus treatment. There were nonsignificant hypoglycemia events between basal insulin groups and the results for the last or seventh day

  9. Infusional mitoxantrone plus bolus melphalan as a stem cell transplant conditioning regimen for multiple myeloma.

    Science.gov (United States)

    Beaven, Anne W; Moore, Dominic T; Sharf, Andrew; Serody, Jonathan S; Shea, Thomas C; Gabriel, Don A

    2011-03-01

    This study combined infusional mitoxantrone with bolus melphalan as a transplant preparative regimen for multiple myeloma. Mitoxantrone was infused over 6 hr on days 6 and 5. Melphalan was given as a 15 min bolus on day 1 followed by autologous transplant on day 0. Thirty-five patients were enrolled; 57% of enrollees had received ≥ 2 prior treatments. The median overall survival was 5 years and 8 months, with 37% of the subjects alive >7 years posttransplantation. Myelosuppression and mucositis were the most frequent adverse events. This regimen is well tolerated and the survival compares well to other transplant trials.

  10. A Study of Oil Viscosity Mental Model

    Science.gov (United States)

    Albaiti; Liliasari; Sumarna, Omay; Abdulkadir Martoprawiro, Muhamad

    2017-02-01

    There is no study regarding on how to learn viscosity of the liquid (e.g. oil) by interconnecting macroscopic, sub-microscopic and symbolic levels. Therefore, the purpose of this research was to study the mental model of the oil viscosity. Intermolecular attractive force of oil constituent on the sub-microscopic level is depicted in the form of mental models. In this research, the viscosity data for some types of oil was measured by using Hoppler method. Viscosity of mineral oil SAE 20W-50, mineral oil SAE 15W-40 and synthetic oil SAE 10W-40 were 1.75, 1.31, and 1.03 Pa s, and the densities of these oils were 908.64, 885.04, and 877.02 kg/m3, respectively. The results showed that the greater density of the mineral oil that is assumed to be composed of linear chains of hydrocarbons, the longer the chain of hydrocarbon linear. Consequently, there are stronger the London force and greater the oil viscosity. The density and viscosity of synthetic oil are lower than that of both mineral oils. Synthetic oil structurally forms polymers with large branching. This structure affects a lower synthetic oil viscosity. This study contributes to construct a mental model of pre-service chemistry teachers.

  11. Viscosity studies of water based magnetite nanofluids

    Energy Technology Data Exchange (ETDEWEB)

    Anu, K.; Hemalatha, J. [Advanced Materials Lab, Department of Physics, National Institute of Technology, Tiruchirappalli, Tamilnadu, India – 620015 (India)

    2016-05-23

    Magnetite nanofluids of various concentrations have been synthesized through co-precipitation method. The structural and topographical studies made with the X-Ray Diffractometer and Atomic Force Microscope are presented in this paper. The density and viscosity studies for the ferrofluids of various concentrations have been made at room temperature. The experimental viscosities are compared with theoretical values obtained from Einstein, Batchelor and Wang models. An attempt to modify the Rosensweig model is made and the modified Rosensweig equation is reported. In addition, new empirical correlation is also proposed for predicting viscosity of ferrofluid at various concentrations.

  12. 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.

  13. 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.

  14. Randomised trial of continuous nasogastric, bolus nasogastric, and transpyloric feeding in infants of birth weight under 1400 g.

    Science.gov (United States)

    Macdonald, P D; Skeoch, C H; Carse, H; Dryburgh, F; Alroomi, L G; Galea, P; Gettinby, G

    1992-04-01

    Forty three infants under 1400 g were fed by a bolus nasogastric, continuous nasogastric, or transpyloric route. There were more complications with transpyloric feeding and no identifiable benefits in the growth rate, oral energy input, or chosen biochemical indices of nutrition. Bolus or continuous nasogastric feeds rather than transpyloric are better routine methods in infants of low birth weight.

  15. Acid diffusion into rice boluses is influenced by rice type, variety, and presence of α-amylase.

    Science.gov (United States)

    Mennah-Govela, Yamile A; Bornhorst, Gail M; Singh, R Paul

    2015-02-01

    Breakdown of rice during gastric digestion may be influenced by rice structure, presence of salivary α-amylase, and hydrolysis by gastric acid. During mastication, saliva is mixed with rice, allowing α-amylase to begin starch hydrolysis. This hydrolysis may continue in the gastric environment depending on the rate at which gastric acid penetrates into the rice bolus. The objective of this study was to determine the acid uptake into rice boluses with and without α-amylase in saliva. Two types each of brown and white rice (medium and long grain), were formed into a cylindrical-shaped bolus. Each bolus was sealed on all sides except one to allow one-dimensional mass transfer, and incubated by immersion in simulated gastric juice at 37 °C under static conditions. Acidity of the boluses was measured by titration after 1 to 96 h of incubation. Effective diffusivity of the gastric juice through the bolus was estimated using MATLAB. Average acidity values ranged from 0.04 mg HCl/g dry matter (medium grain white rice, no incubation) to 10.01 mg HCl/g dry matter (long-grain brown rice, 72 h incubation). The rice type, presence of α-amylase, and incubation time all significantly influenced rice bolus acidity (P starch hydrolysis by α-amylase may continue in the stomach before the gastric acid penetrates the rice bolus, and the rate of acid uptake will depend on the type of rice consumed.

  16. 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.

  17. 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

  18. 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.

  19. Hydrodynamic Electron Flow and Hall Viscosity

    Science.gov (United States)

    Scaffidi, Thomas; Nandi, Nabhanila; Schmidt, Burkhard; Mackenzie, Andrew P.; Moore, Joel E.

    2017-06-01

    In metallic samples of small enough size and sufficiently strong momentum-conserving scattering, the viscosity of the electron gas can become the dominant process governing transport. In this regime, momentum is a long-lived quantity whose evolution is described by an emergent hydrodynamical theory. Furthermore, breaking time-reversal symmetry leads to the appearance of an odd component to the viscosity called the Hall viscosity, which has attracted considerable attention recently due to its quantized nature in gapped systems but still eludes experimental confirmation. Based on microscopic calculations, we discuss how to measure the effects of both the even and odd components of the viscosity using hydrodynamic electronic transport in mesoscopic samples under applied magnetic fields.

  20. 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).

  1. Reproducibility of 5-HT2A receptor measurements and sample size estimations with [18F]altanserin PET using a bolus/infusion approach

    DEFF Research Database (Denmark)

    Haugbøl, Steven; Pinborg, Lars H; Arfan, Haroon M

    2006-01-01

    PURPOSE: To determine the reproducibility of measurements of brain 5-HT2A receptors with an [18F]altanserin PET bolus/infusion approach. Further, to estimate the sample size needed to detect regional differences between two groups and, finally, to evaluate how partial volume correction affects...... reproducibility and the required sample size. METHODS: For assessment of the variability, six subjects were investigated with [18F]altanserin PET twice, at an interval of less than 2 weeks. The sample size required to detect a 20% difference was estimated from [18F]altanserin PET studies in 84 healthy subjects......% (range 5-12%), whereas in regions with a low receptor density, BP1 reproducibility was lower, with a median difference of 17% (range 11-39%). Partial volume correction reduced the variability in the sample considerably. The sample size required to detect a 20% difference in brain regions with high...

  2. Variable viscosity effects on mixed convection heat and mass ...

    African Journals Online (AJOL)

    Variable viscosity effects on mixed convection heat and mass transfer along a ... PROMOTING ACCESS TO AFRICAN RESEARCH ... Keywords: Variable viscosity, Chemical Reaction, Viscous Dissipation, Finite difference method, Suction.

  3. 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.

  4. 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.

  5. 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.

  6. 21 CFR 520.1242b - Levamisole hydrochloride tablet or oblet (bolus).

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Levamisole hydrochloride tablet or oblet (bolus). 520.1242b Section 520.1242b Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.1242b Levamisole hydrochloride tablet...

  7. Pilot study to monitor body temperature of dairy cows with a rumen bolus

    NARCIS (Netherlands)

    Ipema, A.H.; Goense, D.; Hogewerf, P.H.; Houwers, H.W.J.; Roest, H.I.J.

    2008-01-01

    A bolus containing a mote (temperature sensor, processor and radio) was placed in the rumen of a fistulated cow to monitor body temperature. Rumen temperature was measured every minute and stored in the internal buffer of the mote. The measured temperature was also transmitted to a base station by

  8. Use of an automated bolus calculator in MDI-treated type 1 diabetes

    DEFF Research Database (Denmark)

    Schmidt, Signe; Meldgaard, Merete; Serifovski, Nermin

    2012-01-01

    To investigate the effect of flexible intensive insulin therapy (FIIT) and an automated bolus calculator (ABC) in a Danish type 1 diabetes population treated with multiple daily injections. Furthermore, to test the feasibility of teaching FIIT in a 3-h structured course....

  9. Optimization of automatic bolus tracking for timing of the arterial phase of helical liver CT

    Energy Technology Data Exchange (ETDEWEB)

    Sandstede, J.J.W.; Tschammler, A.; Beer, M.; Vogelsang, C.; Wittenberg, G.; Hahn, D. [Wuerzburg Univ. (Germany). Abt. fuer Roentgendiagnostik

    2001-08-01

    The aim of this study was to optimize bolus tracking for timing of the arterial phase of biphasic helical liver CT and to compare optimized bolus tracking to a standard delay. One hundred fifty patients were examined with six protocols: 5- or 10-s delay after triggering at a threshold of 50 or 75 or 100 HU enhancement in the aorta at the origin of the celiac arteries after injection of 120 ml contrast material at 3 ml/s. Optimal arterial enhancement was defined as 20-30% of hepatic enhancement in portal venous phase. Another 50 patients were examined with the optimized protocol and compared to 50 gender- and age-matched patients who underwent a 25-s standard delay. A 10-s delay after the 75-HU threshold resulted in the most patients with an optimal arterial phase (p<0.01). Thirty-one of 75 patients examined with this protocol showed optimal early liver enhancement. Bolus tracking compared with standard delay revealed only a trend for a difference (p=0.07). The outcome of automatic bolus tracking differs depending on the protocol used; however, optimal arterial phase imaging was seen in only 41% of patients, indicating only a trend for superior timing compared with a standard delay. (orig.)

  10. 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.

  11. Viscosity of mafic magmas at high pressures

    Science.gov (United States)

    Cochain, B.; Sanloup, C.; Leroy, C.; Kono, Y.

    2017-01-01

    While it is accepted that silica-rich melts behave anomalously with a decrease of their viscosity at increased pressures (P), the viscosity of silica-poor melts is much less constrained. However, modeling of mantle melts dynamics throughout Earth's history, including the magma ocean era, requires precise knowledge of the viscous properties of silica-poor magmas. We extend here our previous measurements on fayalite melt to natural end-members pyroxenite melts (MgSiO3 and CaSiO3) using in situ X-ray radiography up to 8 GPa. For all compositions, viscosity decreases with P, rapidly below 5 GPa and slowly above. The magnitude of the viscosity decrease is larger for pyroxene melts than for fayalite melt and larger for the Ca end-member within pyroxene melts. The anomalous viscosity decrease appears to be a universal behavior for magmas up to 13 GPa, while the P dependence of viscosity beyond this remains to be measured. These results imply that mantle melts are very pervasive at depth.

  12. Shear viscosities and normal stress differences of rigid liquid-crystalline polymers

    NARCIS (Netherlands)

    Tao, Y.G.; den Otter, Wouter K.; Briels, Willem J.

    2006-01-01

    Shear viscosities as well as first and second normal stress differences of solutions of rigid spherocylindrical colloids are investigated by Brownian dynamics simulations for aspect ratios L/D in a range from 25 to 60 and scaled volume fractions L/D from 0.5 to 4.5. Shear thinning behavior is

  13. Pressure-drop viscosity measurements for gamma-Al2O nanoparticles in water and PG-water mixtures (nanofluids).

    Science.gov (United States)

    Lai, W Y; Phelan, P E; Prasher, R S

    2010-12-01

    Nanofluids have attracted wide attention because of their promising thermal applications. Compared with the base fluid, numerous experiments have generally indicated increases in effective thermal conductivity and convective heat transfer coefficient for suspensions having only a small amount of nanoparticles. It is also known that with the presence of nanoparticles, the viscosity of a nanofluid is greater than its base fluid and deviates from Einstein's classical prediction. However, only a few groups have reported nanofluid viscosity results to date. Therefore, relative viscosity data for gamma-Al2O3 nanoparticles in DI-water and propylene glycol/H2O mixtures are presented here based on pressure drop measurements of flowing nanofluids. Results indicate that with constant wall heat flux, the relative viscosities of nanofluid decrease with increasing volume flow rate. The results also show, based on Brenner's model, that the nanofluid viscosity can be explained in part by the aspect ratio of the aggregates.

  14. Alfaxalone for maintenance of anaesthesia in ponies undergoing field castration: continuous infusion compared with intravenous boluses.

    Science.gov (United States)

    Deutsch, Julia; Ekiri, Abel; de Vries, Annemarie

    2017-04-14

    To compare alfaxalone as continuous intravenous (IV) infusion with intermittent IV injections for maintenance of anaesthesia in ponies undergoing castration. Prospective, randomized, 'blinded' clinical study. A group of 33 entire male Welsh ponies undergoing field castration. After preanaesthetic medication with IV detomidine (10 μg kg(-1)) and butorphanol (0.05 mg kg(-1)), anaesthesia was induced with IV diazepam (0.05 mg kg(-1)) followed by alfaxalone (1 mg kg(-1)). After random allocation, anaesthesia was maintained with either IV alfaxalone 2 mg kg(-1) hour(-1) (group A; n = 16) or saline administered at equal volume (group S; n = 17). When necessary, additional alfaxalone (0.2 mg kg(-1)) was administered IV. Ponies were breathing room air. Using simple descriptive scales, surgical conditions and anaesthesia recovery were scored. Total amount of alfaxalone, ponies requiring additional alfaxalone and time to administration, time from induction to end of infusion and end of infusion to standing were noted. Indirect arterial blood pressure, pulse and respiratory rates, end-expiratory carbon dioxide partial pressure and arterial haemoglobin oxygen saturation were recorded every 5 minutes. Data were analysed using Student t, Mann-Whitney U and chi-square tests, where appropriate (p < 0.05). Total amount of alfaxalone administered after induction of anaesthesia (0.75 ± 0.27 versus 0.17 ± 0.23 mg kg(-1); p < 0.0001) and time to standing (14.8 ± 4 versus 11.6 ± 4 minutes; p = 0.044) were higher in group A compared to group S. Ponies requiring additional alfaxalone boluses [four (group A) versus seven (group S)] and other measured variables were similar between groups; five ponies required oxygen supplementation [three (group A) versus two (group S)]. Continuous IV infusion and intermittent administration of alfaxalone provided similar anaesthesia quality and surgical conditions in ponies undergoing field castration. Less alfaxalone

  15. Cerebral hemodynamic changes measured by gradient-echo or spin-echo bolus tracking and its correlation to changes in ICA blood flow measured by phase-mapping MRI

    DEFF Research Database (Denmark)

    Marstrand, J.R.; Rostrup, Egill; Garde, Ellen;

    2001-01-01

    Changes in cerebral blood flow (CBF) induced by Acetazolamide (ACZ) were measured using dynamic susceptibility contrast MRI (DSC-MRI) with both spin echo (SE) EPI and gradient echo (GE) EPI, and related to changes in internal carotid artery (ICA) flow measured by phase-mapping. Also examined...... was the effect of repeated bolus injections. CBF, cerebral blood volume (CBV), and mean transit time (MTT) were calculated by singular value decomposition (SVD) and by deconvolution using an exponential function as kernel. The results showed no dependency on calculation method. GE-EPI measured a significant...... increase in CBF and CBV in response to ACZ, while SE-EPI measured a significant increase in CBV and MTT. CBV and MTT change measured by SE-EPI was sensitive to previous bolus injections. There was a significant linear relation between change in CBF measured by GE-EPI and change in ICA flow. In conclusion...

  16. 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.

  17. Prediction of the viscosity reduction due to dissolved CO2 of and an elementary approach in the supercritical CO2 assisted continuous particle production of a polyester resin

    NARCIS (Netherlands)

    Nalawade, Sameer P.; Nieborg, Vincent H. J.; Picchioni, Francesco; Janssen, L. P. B. M.

    2006-01-01

    The dissolution of CO2 in a polymer causes plasticization of the polymer and hence, its viscosity is reduced. A model based on the free volume theory has been used for a polyester resin, which shows a considerable reduction in the viscosity due to dissolved M. Therefore, superctitical CO2 has been u

  18. COMPARISON OF SINGLE BOLUS DOSE OF DEXMEDETOMIDINE WITH BOLUS PLUS CONTINUOUS INFUSION OF DEXMEDETOMIDINE ON CHARACTERISTIC OF SPINAL ANAESTHESIA WITH HYPERBARIC BUPIVACAINE

    Directory of Open Access Journals (Sweden)

    Jigar Ashokkumar Rupareliya

    2016-10-01

    Full Text Available BACKGROUND This was a prospective randomised double-blind study to compare the single bolus dose of I.V. dexmedetomidine (0.5 mcg/kg diluted in 10 mL normal saline given slowly before spinal anaesthesia followed by continuous infusion of I.V. dexmedetomidine at the rate of 0.2 mcg/kg/hr. with only single bolus dose of I.V. dexmedetomidine (0.5 mcg/kg diluted in 10 mL normal saline given slowly over 10 mins. before spinal anaesthesia to find out the better technique, which has all the desired effects like prolongation of sensory and motor block and prolong postoperative analgesia with minimal side effects like hypotension and bradycardia. MATERIALS AND METHODS 60 elective surgical patients posted for below umbilical abdominal surgeries and lower limb surgeries with ASA grade I and II with age, weight and height between 20-70 years, 40-70 kg and 150 to 170 cm respectively were selected. Patient was randomly allotted in two group of 30 patients. Patients in both the groups received I.V. dexmedetomidine bolus at the rate of 0.5 mcg/kg diluted in 10 mL normal saline slowly over 10 mins. using infusion pump prior to spinal anaesthesia with 3 mL 0.5% bupivacaine. After spinal anaesthesia, patient in Group D received infusion of dexmedetomidine at the rate of 0.2 mcg/kg/hr. (100 mcg dexmedetomidine diluted in 50 mL normal saline, i.e. 2 mcg/mL by infusion pump till the end of surgery. In Group N, patient received infusion of 50 mL normal saline at predetermined rate till end of surgery. The onset of sensory and motor block, duration of sensory and motor block, haemodynamic stability and quality of surgical anaesthesia, intraoperative complications, postoperative analgesia and side effects were recorded. RESULTS Our study concluded that I.V. supplementation of bolus followed by continuous infusion of Inj. Dexmedetomidine prolong the duration of sensory and motor block induced with spinal bupivacaine 0.5% hyperbaric. It provides the stable haemodynamic

  19. MPI as high temporal resolution imaging technique for in vivo bolus tracking of Ferucarbotran in mouse model

    Science.gov (United States)

    Jung, C.; Salamon, J.; Hofmann, M.; Kaul, M. G.; Adam, G.; Ittrich, H.; Knopp, T.

    2016-03-01

    Purpose: The goal of this study was to achieve a real time 3D visualisation of the murine cardiovascular system by intravenously injected superparamagnetic nanoparticles using Magnetic particle imaging (MPI). Material and Methods: MPI scans of FVB mice were performed using a 3D imaging sequence (1T/m gradient strength, 10mT drive-field strength). A dynamic scan with a temporal resolution of 21.5ms per 3D volume acquisition was performed. 50μl ferucarbotran (Resovist®, Bayer Healthcare AG) were injected into the tail vein after baseline MPI measurements. As MPI delivers no anatomic information, MRI scans at a 7T ClinScan (Bruker) were performed using a T2-weighted 2D TSE sequence. The reconstruction of the MPI data was performed on the MPI console (ParaVision 6.0/MPI, Bruker). Image fusion was done using additional image processing software (Imalytics, Philips). The dynamic information was extracted using custom software developed in the Julia programming environment. Results: The combined MRI-MPI measurements were carried out successfully. MPI data clearly demonstrated the passage of the SPIO tracer through the inferior vena cava, the heart and finally the liver. By co-registration with MRI the anatomical regions were identified. Due to the volume frame rate of about 46 volumes per second a signal modulation with the frequency of the heart beat was detectable and a heart beat of 520 beats per minute (bpm) has been assumed. Moreover, the blood flow velocity of approximately 5cm/s in the vena cava has been estimated. Conclusions: The high temporal resolution of MPI allows real-time imaging and bolus tracking of intravenous injected nanoparticles and offers a real time tool to assess blood flow velocity.

  20. 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.

  1. Frequent use of an automated bolus advisor improves glycemic control in pediatric patients treated with insulin pump therapy: results of the Bolus Advisor Benefit Evaluation (BABE) study.

    Science.gov (United States)

    Ziegler, Ralph; Rees, Christen; Jacobs, Nehle; Parkin, Christopher G; Lyden, Maureen R; Petersen, Bettina; Wagner, Robin S

    2016-08-01

    The relationship between frequency and sustained bolus advisor (BA) use and glycemic improvement has not been well characterized in pediatric populations. The objective of this study is to assess the impact of frequent and persistent BA use on glycemic control among pediatric type 1 diabetes patients. In this 6-month, single-center, retrospective cohort study, 104 children [61 girls, mean age: 12.7 yr, mean HbA1c 8.0 (1.6)% [64 (17.5) mmol/mol

  2. EFFECT OF A BITTER BOLUS ON ORAL, PHARYNGEAL AND ESOPHAGEAL TRANSIT OF HEALTHY SUBJECTS

    Directory of Open Access Journals (Sweden)

    Leda Maria Tavares ALVES

    2013-03-01

    Full Text Available Context During swallowing, boluses stimulate sensory receptors of the oral, pharyngeal, laryngeal, and esophageal regions. Sweet and tasteless foods are more acceptable for swallowing than bitter foods. A bitter bolus is unpleasant for most subjects. Our hypothesis was that the ingestion of a bitter bolus might alter the oral behavior, pharyngeal and esophageal transit when compared to a sweet bolus. Objective To evaluate whether the bitter taste of a liquid bolus causes alteration on oral, pharyngeal and/or esophageal transit in normal subjects in comparison with sweet bolus.' Method Scintigraphic evaluation of oral, pharyngeal and esophageal transit was performed in 43 asymptomatic subjects, 22 women and 21 men, ages 23-71 years, without problems with the ingestion of liquid and solid foods, and without digestive, cardiac or neurologic diseases. Each subject swallowed in random sequence and at room temperature 5 mL of a liquid bolus with bitter taste, prepared with 50 mL of water with 2 g of leaves of Peumus boldus, heated until boiling (boldus tea, and 5 mL of a liquid bolus with sweet taste, prepared with 50 mL of water with 3 g of sucrose, both labeled with 37 MBq of technetium phytate (Tc99m. Results There was no difference between the bitter bolus and the sweet bolus in mouth, pharynx and esophageal transit and clearance duration and in the amount of residues. Conclusion A bitter bolus, considered an unpleasant bolus, does not alter the duration of oral, pharyngeal and esophageal phases of swallowing, when compared with a sweet bolus, considered a pleasant bolus. Contexto Durante a deglutição o bolo estimula os receptores sensoriais da boca, faringe, laringe e esôfago. Os alimentos doces e sem gosto são mais aceitáveis para a deglutição do que os alimentos amargos, que tem gosto desagradável para a maioria dos indivíduos. A hipótese destes autores era que a ingestão de um bolo amargo pode alterar o trânsito oral

  3. Viscosity of Campi Flregrei (Italy) magmas

    Science.gov (United States)

    Misiti, Valeria; Vetere, Francesco; Scarlato, Piergiorgio; Behrens, Harald; Mangiacapra, Annarita; Freda, Carmela

    2010-05-01

    Viscosity is an important factor governing both intrusive and volcanic processes. The most important parameters governing silicate melts viscosity are bulk composition of melt and temperature. Pressure has only minor effect at crustal depths, whereas crystals and bubbles have significant influence. Among compositional parameters, the water content is critical above all in terms of rheological behaviour of melts and explosive style of an eruption. Consequently, without an appropriate knowledge of magma viscosity depending on the amount of dissolved volatiles, it is not possible to model the processes (i.e., magma ascent, fragmentation, and dispersion) required to predict realistic volcanic scenarios and thus forecast volcanic hazards. The Campi Flegrei are a large volcanic complex (~150 km2) located west of the city of Naples, Italy, that has been the site of volcanic activity for more than 60 ka and represents a potential volcanic hazard owing to the large local population. In the frame of a INGV-DPC (Department of Civil Protection) project devoted to design a multidisciplinary system for short-term volcano hazard evaluation, we performed viscosity measurements, under dry and hydrous conditions, of primitive melt compositions representative of two Campi Flegrei eruptions (Minopoli-shoshonite and Fondo Riccio-latite). Viscosity of the two melts have been investigated in the high temperature/low viscosity range at atmospheric pressure in dry samples and at 0.5 GPa in runs having water content from nominally anhydrous to about 3 wt%. Data in the low temperature/high viscosity range were obtained near the glass transition temperature at atmospheric pressure on samples whose water contents vary from 0.3 up to 2.43 wt%. The combination of high- and low-viscosity data permits a general description of the viscosity as a function of temperature and water content using a modified Tamman-Vogel-Fulcher equation. logν = a+ --b--+ --d--×exp(g × w-) (T - c) (T - e) T (1) where

  4. 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.

  5. 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.

  6. Viscosity model for fully liquid silicate melt

    Directory of Open Access Journals (Sweden)

    Zhang Guo-Hua

    2012-01-01

    Full Text Available A model for estimating the viscosity of silicate melt as derived in our previous paper is extended to the system containing MgO, CaO, SrO, BaO, Li2O, Na2O, K2O, which can express the nonlinear variation of activation energy of viscosity with the composition. It is found that the optimized parameters of model which characterize the deforming ability of bonds around non-bridging oxygen decrease with increasing the bond strength of M-O bond expressed by I=2Q/RMz+ + rO2-2 (where Q is the valence of cation M; r is the radius. It is pointed out that viscosity is not only determined by the bond strength, but also by the radius of cation which is defined as the size effect. The radius of cation plays paradox roles in the two factors: smaller radius leads to a stronger bond, thus a higher viscosity; while cations with smaller radius are easier to diffuse when neglecting the interaction force, thus a lower viscosity will be.

  7. 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.

  8. OPTIMAL REGIMENS OF THE BASAL-BOLUS INSULIN THERAPY IN ADOLESCENTS WITH TYPE 1 DIABETES MELLITUS

    Directory of Open Access Journals (Sweden)

    G. A. Galkina

    2015-01-01

    Full Text Available This study was aimed to determine peculiarities in regimens of the pump insulin therapy and to reveal the optimal basal-to-bolus insulin ratio that are necessary for achieving optimal glycemic control in adoles-cents with type 1 diabetes mellitus (T1DM.  82 adolescents at the age of 14–18 with T1DM, using continuous subcutaneous insulin infusion (CSII from 5 months to 7.5 years were monitored with continuous glucose monitoring (CGM system «Guar-dian Real Time» or CGM system, built in MiniMed Paradigm Revel System 722 (Medtronic Minimed, USA. Assessing the quality of glycaemic control was based on the level of glycated haemoglobin (HbA1c. The results of CGM were reviewed and average for 3 days performances: total daily dose of insulin, dose of basal and bolus insulin, basal-to-bolus insulin ratio, carbohydrate content of the meal, expressed in BE, carbohydrate ratio, insulin sensitivity factor were determined. The patients were subdivided into 2 groups: group 1 – adolescents with the optimal/suboptimal glycemic control (n = 55, 2 – adolescents with long-standing poorly controlled T1DM (n = 27. Average total daily dose of basal insulin (U in a day, U per kg in a day in adolescents group 1 was significantly higher, com-pared with patients in group 2 (р = 0.043; р = 0.038 respectively. Patients in group 2 received more car-bohydrates with a meal intake and had higher doses of average total daily bolus insulin. The average ba-sal-to-bolus ratio from group 1 patients was 51/49%, compared with group 2 patients – 45/55% (р = 0.026.  An important condition for achieving optimal glycemic control is a high level of compliance and skills of adolescents. Optimal well-balanced basal-to-bolus insulin ratio in adolescents with T1DM on CSII, which can provide improvements in blood glucose management and reducing the risk of complications of the disease, is 51/49%. 

  9. Computation of shear viscosity of colloidal suspensions by SRD-MD

    Energy Technology Data Exchange (ETDEWEB)

    Laganapan, A. M. K.; Videcoq, A., E-mail: arnaud.videcoq@unilim.fr; Bienia, M. [SPCTS, UMR 7315, ENSCI, CNRS, Centre Européen de la Céramique, 12 rue Atlantis, 87068 Limoges Cedex (France); Ala-Nissila, T. [COMP CoE at the Department of Applied Physics, Aalto University School of Science, P.O. Box 11000, FIN-00076 Aalto, Espoo (Finland); Department of Physics, Brown University, Providence, Rhode Island 02912-1843 (United States); Bochicchio, D.; Ferrando, R. [Dipartimento di Fisica and CNR-IMEM, via Dodecaneso 33, Genova I-16146 (Italy)

    2015-04-14

    The behaviour of sheared colloidal suspensions with full hydrodynamic interactions (HIs) is numerically studied. To this end, we use the hybrid stochastic rotation dynamics-molecular dynamics (SRD-MD) method. The shear viscosity of colloidal suspensions is computed for different volume fractions, both for dilute and concentrated cases. We verify that HIs help in the collisions and the streaming of colloidal particles, thereby increasing the overall shear viscosity of the suspension. Our results show a good agreement with known experimental, theoretical, and numerical studies. This work demonstrates the ability of SRD-MD to successfully simulate transport coefficients that require correct modelling of HIs.

  10. Investigation of epoxy matrix viscosity in the initial stage of its formation

    Science.gov (United States)

    Gilev, V. G.; Kondyurin, A. V.; Rusakov, S. V.

    2017-06-01

    The present study includes experimental investigations of rheological properties of the epoxy composite matrix based on epoxy resin L and hardener EPH 161. It is shown that the temperature dependences of the oligomer viscosity and the hardener can be satisfactorily described by the Arrhenius equation. Dependence of epoxy resin viscosity on temperature and volume concentration of the hardener at the initial stage of the polymerization process is investigated. It is shown that the experimental results can be generalized with one universal dependence of concentration and temperature.

  11. SU-C-213-05: Evaluation of a Composite Copper-Plastic Material for a 3D Printed Radiation Therapy Bolus

    Energy Technology Data Exchange (ETDEWEB)

    Vitzthum, L; Ehler, E; Sterling, D; Reynolds, T; Higgins, P; Dusenbery, K [University of Minnesota, Minneapolis, MN (United States)

    2015-06-15

    Purpose: To evaluate a novel 3D printed bolus fabricated from a copper-plastic composite as a thin flexible, custom fitting device that can replicate doses achieved with conventional bolus techniques. Methods: Two models of bolus were created on a 3D printer using a composite copper-PLA/PHA. Firstly, boluses were constructed at thicknesses of 0.4, 0.6 and 0.8 mm. Relative dose measurements were performed under the bolus with an Attix Chamber as well as with radiochromic film. Results were compared to superficial Attix Chamber measurements in a water equivalent material to determine the dosimetric water equivalence of the copper-PLA/PHA plastic. Secondly, CT images of a RANDO phantom were used to create a custom fitting bolus across the anterolateral scalp. Surface dose with the bolus placed on the RANDO phantom was measured with radiochromic film at tangential angles with 6, 10, 10 flattening filter free (FFF) and 18 MV photon beams. Results: Mean surface doses for 6, 10, 10FFF and 18 MV were measured as a percent of Dmax for the flat bolus devices of each thickness. The 0.4 mm thickness bolus was determined to be near equivalent to 2.5 mm depth in water for all four energies. Surface doses ranged from 59–63% without bolus and 85–90% with the custom 0.4 mm copper-plastic bolus relative to the prescribed dose for an oblique tangential beam arrangement on the RANDO phantom. Conclusion: Sub-millimeter thickness, 3D printed composite copper-PLA/PHA bolus can provide a build-up effect equivalent to conventional bolus. At this thickness, the 3D printed bolus allows a level of flexure that may provide more patient comfort than current 3D printing materials used in bolus fabrication while still retaining the CT based custom patient shape. Funding provided by an intra-department grant of the University of Minnesota Department of Radiation Oncology.

  12. 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.

  13. 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.

  14. 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...

  15. 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.

  16. 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.

  17. 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...

  18. 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...

  19. 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.

  20. 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).

  1. Viscosity-temperature correlation for crude oils

    Energy Technology Data Exchange (ETDEWEB)

    Shanshool, J.; Niazi, E. [Chemical Engineering Dept., Al-Nahrain Univ., Baghdad (Iraq)

    2004-12-01

    The kinematic viscosities of crude oils were measured over a temperature range 10-50 C and at atmospheric pressure. These data were used to develop a method to predict the viscosity of crude oils, based upon API gravity, pour point and molecular weight. The proposed new correlation has been verified using data base of about twelve Middle East crude oils, showing significantly improved correlation, with an average absolute deviation of 5.3%. The correlation is also applicable to crude oils with a wide range of API gravities, pour points and molecular weights. (orig.)

  2. Optimum bolus wizard settings in insulin pumps in children with Type 1 diabetes

    DEFF Research Database (Denmark)

    Andersen, A J B; Ostenfeld, A; Pipper, C B

    2016-01-01

    AIM: To evaluate current insulin pump settings in an optimally regulated paediatric population using bolus wizard. METHODS: We used a retrospective study design to analyse data from 124 children on insulin pump therapy who had optimum HbA1c levels [.... Furthermore, duration of insulin pump treatment was significantly associated with insulin sensitivity factor and percentage bolus/basal was significantly associated with insulin to carbohydrate factor. Gender, diabetes duration and BMI were not associated with any of the calculation factors. CONCLUSION......: Optimum insulin pump settings at pump initiation depend on both insulin requirements and use of the pump. Settings need to be individualized because the standardized calculation factors are not constant for children. There is a need to develop specific age- and insulin dose-dependent calculation factors....

  3. Development and Dosimetric Characterization of a Tissue Substitute (Bolus) For Use in Linear Accelerator Electron Radiotherapy

    Science.gov (United States)

    Estrada Trujillo, Jorge; Villaseñor Navarro, Luis Felipe; Mitsoura, Eleni

    2003-09-01

    We propose the design of a new custom made material, to be used as a tissue substitute in external beam electron radiotherapy, based on cotton fabric and beeswax. Due to its inexpensive, easy preparation, constant thickness, flexibility, uniform density and physical properties similar to those of soft tissue, this bolus will insure personalized optimal dose build up and dose distribution in irregular treatment regions. Materials and Methods: We used commercial Campeche beeswax and 100% cotton fabric to prepare the bolus. Beeswax's physical characteristics were determined by thermal and density analysis. Its chemical properties are to be determined by electronic microcopy. We performed quality control tests and calibration of the Varian 2100C linear accelerator. The tissue equivalence of the material is established for a range of electron energies (6, 9, 12, 16, 20 MeV) using a water equivalent solid phantom (PTW; Freiburg, Germany) and a plane parallel ionization chamber (PTW) associated to a PTW electrometer. Results: Beeswax's absolute density was found to be 0.9181g/ml at 21°C, with a melting point of 45°C. For the bolus elaboration, the cotton fabric was soaked in liquid beeswax and thin sheets of approximately 1 mm were obtained. These presented high flexibility, physical stability (color, texture, thickness) and homogeneity. Determination of this dosimetric characteristics and equivalent thickness are still in process. Discussion and conclusions: Our preliminary results suggest that the tissue substitute is easily made, inexpensive to produce, molds well to the treatment area and its positioning is easy and reproducible over the course of the treatment. So we consider that it's a good alternative to the commercial bolus.

  4. Continuous-infusion cisplatin and bolus 5-fluorouracil in colorectal carcinoma.

    Science.gov (United States)

    Posner, M R; Belliveau, J F; Weitberg, A B; Sabbath, K; Wiemann, M C; Cummings, F J; Calabresi, P

    1987-10-01

    Twenty-one evaluable patients with metastatic colorectal carcinoma were treated with a combination of continuous-infusion cisplatin (25 mg/m2/day X 3 days) and bolus 5-fluorouracil (400 mg/m2/day X 3 days). Toxicity was minimal. Seven patients (33%) responded. All responses were observed among the 16 previously untreated patients (44%) and lasted a median of 30 weeks. The results indicate the need for phase III trials of this treatment.

  5. Optimising the scan delay for arterial phase imaging of the liver using the bolus tracking technique

    Science.gov (United States)

    Chan, RS; Kumar, G; Abdullah, BJJ; Ng, KH; Vijayananthan, A; Mohd. Nor, H; Liew, YW

    2011-01-01

    Objective: To optimize the delay time before the initiation of arterial phase scan in the detection of focal liver lesions in contrast enhanced 5 phase liver CT using the bolus tracking technique. Patients and Methods: Delay - the interval between threshold enhancement of 100 hounsfield unit (HU) in the abdominal aorta and commencement of the first arterial phase scan. Using a 16 slice CT scanner, a plain CT of the liver was done followed by an intravenous bolus of 120 ml nonionic iodinated contrast media (370 mg I/ml) at the rate of 4 mL/s. The second phase scan started immediately after the first phase scan. The portal venous and delay phases were obtained at a fixed delay of 60 s and 90 s from the beginning of contrast injection. Contrast enhancement index (CEI) and subjective visual conspicuity scores for each lesion were compared among the three groups. Results: 84 lesions (11 hepatocellular carcinomas, 17 hemangiomas, 39 other hypervascular lesions and 45 cysts) were evaluated. CEI for hepatocellular carcinomas appears to be higher during the first arterial phase in the 6 seconds delay group. No significant difference in CEI and mean conspicuity scores among the three groups for hemangioma, other hypervascular lesions and cysts. Conclusion: The conspicuity of hepatocellular carcinomas appeared better during the early arterial phase using a bolus tracking technique with a scan delay of 6 seconds from the 100 HU threshold in the abdominal aorta. PMID:22287986

  6. Real-time myocardial contrast echocardiography in rat: infusion versus bolus administration.

    Science.gov (United States)

    Su, Hai-Li; Qian, Yun-Qiu; Wei, Zhang-Rui; He, Jian-Guo; Li, Guo-Quan; Zhang, Jun; Zhou, Xiao-Dong; Jing, Wang

    2009-05-01

    To compare the feasibility of real-time myocardial contrast echocardiography (MCE) in rats with infusion and bolus administration of a second-generation ultrasound contrast agent BR1. B-mode real-time MCE was performed in 12 Sprague Dawley rats following the BR1 infusion or bolus injection. The myocardium signal intensity (SI) was plotted against time and was fitted to exponential functions. The plateau SI (A) and rate of SI increase (beta) for the infusion study and peak signal intensity (PSI) for the bolus study were obtained. (99m)Tc-Sestamibi and Evans blue were used to assess myocardial blood perfusion and to calculate the myocardium perfusion defect area ex vivo. High-quality real-time MCE images were successfully obtained using each method. At baseline, all LV segments showed even contrast distribution. Following left anterior descending coronary artery (LAD) ligation, significant perfusion defect was observed in LAD beds with a significantly decreased A* beta and PSI values compared with LCx beds (Infusion: A*beta (LAD): 5.42 +/- 1.57 dB, A*beta (LCx): 46.52 +/- 5.32 dB, p rats and the infusion method was more suitable for quantitative analysis of myocardial blood flow.

  7. Physiological changes after fluid bolus therapy in sepsis: a systematic review of contemporary data.

    Science.gov (United States)

    Glassford, Neil J; Eastwood, Glenn M; Bellomo, Rinaldo

    2014-12-27

    Fluid bolus therapy (FBT) is a standard of care in the management of the septic, hypotensive, tachycardic and/or oliguric patient. However, contemporary evidence for FBT improving patient-centred outcomes is scant. Moreover, its physiological effects in contemporary ICU environments and populations are poorly understood. Using three electronic databases, we identified all studies describing FBT between January 2010 and December 2013. We found 33 studies describing 41 boluses. No randomised controlled trials compared FBT with alternative interventions, such as vasopressors. The median fluid bolus was 500 ml (range 100 to 1,000 ml) administered over 30 minutes (range 10 to 60 minutes) and the most commonly administered fluid was 0.9% sodium chloride solution. In 19 studies, a predetermined physiological trigger initiated FBT. Although 17 studies describe the temporal course of physiological changes after FBT in 31 patient groups, only three studies describe the physiological changes at 60 minutes, and only one study beyond this point. No studies related the physiological changes after FBT with clinically relevant outcomes. There is a clear need for at least obtaining randomised controlled evidence for the physiological effects of FBT in patients with severe sepsis and septic shock beyond the period immediately after its administration.

  8. Pharmacokinetics of marbofloxacin, after one bolus oral administration in buffaloes calves: Preliminary study.

    Directory of Open Access Journals (Sweden)

    M.I. San Andrés

    2010-02-01

    Full Text Available Buffalo breeding system has a great economic importance in South-America, principally in marginal or sub-tropical lands. The therapeutic recommendations applied to a single ruminant species are extrapolated to others but important differences among those were recognized. Marbofloxacin bolus is indicated in the treatment of neonatal gastroenteritis caused by Escherichia coli, in calves (25-50kg. The aim of this study was determined the pharmacokinetic behaviour of marbofloxacin after oral administration, as bolus, following the label approved recommendations to cattle. One bolus (50 mg was administered in two clinically healthy buffaloes (two days-old, 48-50kg. Plasma concentrations of the marbofloxacin were determined by a HPLC/u.v. method. After oral administration, the values obtained were: tmax=0.5-6h, Cmax= 1.19-0.04μg/mL, AUCt=1.57-0.38μg·h/mL and MRTt= 3.34-6.92h, for calves 1 and 2 respectively. Fluoroquinolones act by concentration dependant killing mechanism, so high plasma concentration initially is important. For this reason, the recommended dose of 1mg/kg is inadequate in buffaloes.

  9. Bolus electron conformal therapy for the treatment of recurrent inflammatory breast cancer: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Michelle M., E-mail: mmkim@mdanderson.org [Department of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Kudchadker, Rajat J.; Kanke, James E.; Zhang, Sean; Perkins, George H. [Department of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States)

    2012-07-01

    The treatment of locoregionally recurrent breast cancer in patients who have previously undergone radiation therapy is challenging. Special techniques are often required that both eradicate the disease and minimize the risks of retreatment. We report the case of a patient with an early-stage left breast cancer who developed inflammatory-type recurrence requiring re-irradiation of the chest wall using bolus electron conformal therapy with image-guided treatment delivery. The patient was a 51-year-old woman who had undergone lumpectomy, axillary lymph node dissection, and adjuvant whole-breast radiation therapy for a stage I left breast cancer in June 1998. In March 2009, she presented at our institution with biopsy-proven recurrent inflammatory carcinoma and was aggressively treated with multi-agent chemotherapy followed by mastectomy that left a positive surgical margin. Given the patient's prior irradiation and irregular chest wall anatomy, bolus electron conformal therapy was used to treat her chest wall and draining lymphatics while sparing the underlying soft tissue. The patient still had no evidence of disease 21 months after treatment. Our results indicate that bolus electron conformal therapy is an accessible, effective radiation treatment approach for recurrent breast cancer in patients with irregular chest wall anatomy as a result of surgery. This approach may complement standard techniques used to reduce locoregional recurrence in the postmastectomy setting.

  10. Understanding the importance of the viscosity contrast between the sample solvent plug and the mobile phase and its potential consequences in two-dimensional high-performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Shalliker, R. Andrew [University of Western Sydney, Australia; Guiochon, Georges A [ORNL

    2009-01-01

    The effect of solvent viscosity mismatch on elution performance in reversed-phase HPLC was studied using moment analysis. Two conditions were tested: (1) the mobile phase viscosity was less than the injection plug viscosity, and (2) the mobile phase viscosity was greater than the injection plug viscosity. Under the first condition, retention time and elution performance decreased as the viscosity contrast between the mobile phase and injection plug increased. The effect on performance was more marked as the injection volume increased. A decrease in performance of 12% for compounds with retention factors up to 2.8 was apparent even when the viscosity contrast was only 0.165 cP. In the second set of conditions, elution performance was actually observed to increase, by as much as 25% for a 40 {micro}L injection, as the viscosity contrast between the mobile phase and the solute plug increased. No change in the retention factor was observed. This behaviour was attributed to the shape of an injection plug as it enters into the column, whereby a low viscosity plug permeates away from the wall when the column contains a higher viscosity mobile phase, and vice a versa for a high viscosity plug entering a low viscosity mobile phase. At no stage was either a band splitting or shoulders observed with viscosity contrasts up to 1.283 cP, as could have been expected.

  11. 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.

  12. Density, viscosity and refractive index of the dimethyl sulfoxide + o-xylene system

    Directory of Open Access Journals (Sweden)

    OANA CIOCIRLAN

    2009-03-01

    Full Text Available This work reports the experimental results of the densities, viscosities and refractive indices between 298.15 and 323.15 K of the dimethyl sulfoxide + o-xylene system over the entire composition range of the mixtures. The excess molar volumes (VE, viscosity deviations (Δn, excess Gibbs energy of activation of viscous flow (G*E and deviations in the refraction (ΔR were calculated from the experimental data; all the computed quantities were fitted to the Redlich–Kister equation. The system exhibits moderate negative values for the investigated excess properties. The resulting excess functions were interpreted in structural and interactional terms. From the experimental data, the thermodynamic functions of the activation of viscous flow were estimated. The viscosity data were correlated with several semi-empirical equations. The two-parameter McAllister equation can give very good results.

  13. 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.

  14. 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...

  15. 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...

  16. 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.

  17. 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...

  18. 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.

  19. 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.

  20. Viscosity-dependent Janus particle chain dynamics.

    Science.gov (United States)

    Ren, Bin; Kretzschmar, Ilona

    2013-12-03

    Iron oxide (Fe3O4) Janus particles assemble into staggered chains parallel to the field lines in an ac electric field. Subsequent application of an external magnetic field leads to contraction of the staggered chains into double chains. The relation between the viscosity of the surrounding solution and the contraction rate of the iron oxide Janus particle chains is studied. Further, the influence of particle size and chain length (i.e., number of particles in chain) on the contraction rate is investigated. The base material for the Janus structure is silica (SiO2) with particle sizes of 1, 2, and 4 μm, and the cap material is Fe3O4. Addition of increasing amounts of glycerol to the aqueous system reveals that the contraction dynamics strongly correlate with the viscosity of the solution. The average chain contraction rate for each particle size can be fitted in the low viscosity range from 1 to 30 mPa·s with a power function of the form A/μ(0.9) - B/μ, in which the coefficients A and B are particle size, electric field, and magnetic-field-dependent constants. Using this function, the viscosity of an unknown solution can be determined, thereby pointing to the potential application of these Janus particle chain assemblies as in situ microviscometers.

  1. 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.

  2. 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.

  3. 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.

  4. Density, Viscosity, Sound Speed, and Thermoacoustical Parameters of Benzaldehyde with Chlorobenzene or Nitrobenzene at 303.15 K, 308.15 K, and 313.15 K

    Science.gov (United States)

    Lavanya, T. G.; Saravanakumar, K.; Baskaran, R.; Kubendran, T. R.

    2013-07-01

    The values of the density, viscosity, and speed of sound for binary liquid mixtures of benzaldehyde with chlorobenzene or nitrobenzene have been measured over the entire range of composition at (303.15, 308.15, and 313.15) K. These values have been used to calculate the excess molar volume (), and excess free volume (). McAllister's three-body interaction model is used for correlating the kinematic viscosity of binary mixtures. The thermophysical properties (density, viscosity, and ultrasonic velocity) under study were fit to the Jouyban-Acree model.

  5. 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

  6. Effects of different strategies of mineral supplementation (marine algae alone or combined with rumen boluses) in organic dairy systems.

    Science.gov (United States)

    López-Alonso, M; Rey-Crespo, F; Orjales, I; Rodríguez-Bermúdez, R; Miranda, M

    2016-10-01

    This study was designed to evaluate the effect of marine algae supplementation alone or in combination with a regular mineral supplement (rumen boluses) to improve the mineral status in organic dairy cattle and their effect on the milk mineral composition, milk production, composition (% of fat and protein) and quality (SCC). Thirty-two Holstein Friesian lactating cows were randomly selected and assigned to the algae (A), boluses (B), algae+boluses (AB) and control group (C). For the algae groups (A, AB), a supplement composed of Sea Lettuce (80%), Japanese Wireweed (17.5%) and Furbelows (2.5%) was formulated to be given to the cows at the rate of 100 g/animal per day (A1) for the length of 4 weeks. In the second half of the experiment (weeks 5-8), the algae mixture was reformulated and the proportion of Furbelows was increased from 2.5% to 5.0% with a subsequent decrease of Lettuce to 77.5% (A2). In the boluses group (B), each cow received 2 boluses after calving. Blood (serum) and milk samples were collected at 2 and 4 week intervals, respectively, and analysed for trace element concentrations by ICP-MS. Information related to the milk composition and SCC during a 305-day lactation for each animal were obtained from the Dairy Records Management System. The supplementation with algae, boluses or the combination of both treatments showed a statistically significant effect on the iodine (algae), selenium (boluses) and cobalt (algae+boluses) status of the animals. In milk, treatments had a statistical significant increase on iodine, and a tendency to increase selenium concentrations. The assayed algae mixture combined with another source of selenium could be an effective tool to improve the mineral status in serum and milk. Journal of Animal Physiology and Animal Nutrition © 2016 Blackwell Verlag GmbH.

  7. Microcantilever based disposable viscosity sensor for serum and blood plasma measurements.

    Science.gov (United States)

    Cakmak, Onur; Elbuken, Caglar; Ermek, Erhan; Mostafazadeh, Aref; Baris, Ibrahim; Erdem Alaca, B; Kavakli, Ibrahim Halil; Urey, Hakan

    2013-10-01

    This paper proposes a novel method for measuring blood plasma and serum viscosity with a microcantilever-based MEMS sensor. MEMS cantilevers are made of electroplated nickel and actuated remotely with magnetic field using an electro-coil. Real-time monitoring of cantilever resonant frequency is performed remotely using diffraction gratings fabricated at the tip of the dynamic cantilevers. Only few nanometer cantilever deflection is sufficient due to interferometric sensitivity of the readout. The resonant frequency of the cantilever is tracked with a phase lock loop (PLL) control circuit. The viscosities of liquid samples are obtained through the measurement of the cantilever's frequency change with respect to a reference measurement taken within a liquid of known viscosity. We performed measurements with glycerol solutions at different temperatures and validated the repeatability of the system by comparing with a reference commercial viscometer. Experimental results are compared with the theoretical predictions based on Sader's theory and agreed reasonably well. Afterwards viscosities of different Fetal Bovine Serum and Bovine Serum Albumin mixtures are measured both at 23°C and 37°C, body temperature. Finally the viscosities of human blood plasma samples taken from healthy donors are measured. The proposed method is capable of measuring viscosities from 0.86 cP to 3.02 cP, which covers human blood plasma viscosity range, with a resolution better than 0.04 cP. The sample volume requirement is less than 150 μl and can be reduced significantly with optimized cartridge design. Both the actuation and sensing are carried out remotely, which allows for disposable sensor cartridges. Copyright © 2013. Published by Elsevier Inc.

  8. VISCOSITY BEHAVIOR OF PS/TOLUENE SOLUTION IN DILUTE AND EXTREMELY DILUTE CONCENTRATION REGION

    Institute of Scientific and Technical Information of China (English)

    DU Dengxue; ZUO Ju; CHEN Yu; NING Hui

    2003-01-01

    The influences of both the volume of PS/toluene solution in the Ubbelohde viscometer and the precision of the time measuring on the viscosity behavior in dilute and extremely diluteconcentration region are investigated It was found that the influence of the former can neglect, but that of the latter is so prominent that the data fluctuate bitterly and linearity of the curve of the reduced viscosity vs. Concentration (ηsp/c~c) becomes too bad to obey the Huggins equation down to the extremely dilute region, despite the error of the flow times △t ≤ 0.2s, which is permitted by the conventional method of viscosity measurement. Through strict mathematical analyses, it was found that thc error (E) of the reduced viscosity is in proportion and inverse proportion to △t and concentration c, respectively. So the less the concentration, the more the error is. Consequently, a lowest concentration limit cL corresponding to given experimental error may exist and it will be meaningless for further operation below cL because of the great fluctuation of the data. Therefore, itneeds to seriously reconsider the application of the conventional method of Ubbelohde viscosity measurement in the extremely dilute polymer solution under traditional conditions because of the great influence of the experimental error.

  9. An empirical method to estimate the viscosity of mineral oil by means of ultrasonic attenuation.

    Science.gov (United States)

    Ju, Hyeong; Gottlieb, Emanuel; Augenstein, Donald; Brown, Gregor; Tittmann, Bernhard

    2010-07-01

    This paper presents an empirical method for measuring the viscosity of mineral oil. In a built-in pipeline application, conventional ultrasonic methods using shear reflectance or rheological and acoustical phenomena may fail because of attenuated shear wave propagation and an unpredictable spreading loss caused by protective housings and comparable main flows. The empirical method utilizing longitudinal waves eliminates the unknown spreading loss from attenuation measurements on the object fluid by removing the normalized spreading loss per focal length with the measurement of a reference fluid of a known acoustic absorption coefficient. The ultrasonic attenuation of fresh water as the reference fluid and mineral oil as the object fluid were measured along with the sound speed and effective frequency. The empirical equation for the spreading loss in the reference fluid is determined by high-order polynomial fitting. To estimate the shear viscosity of the mineral oil, a linear fit is applied to the total loss difference between the two fluids, whose slope (the absorption coefficient) is combined with an assumed shear-to-volume viscosity relation. The empirical method predicted the viscosities of two types of the mineral oil with a maximum statistical uncertainty of 8.8% and a maximum systematic error of 12.5% compared with directly measured viscosity using a glass-type viscometer. The validity of this method was examined by comparison with the results from theoretical far-field spreading.

  10. Carotid MR angiography with traditional bolus timing: clinical observations and Fourier-based modelling of contrast kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Menke, Jan [University Hospital, Department of Diagnostic Radiology, Goettingen (Germany)

    2009-11-15

    This study analyses the relation between image quality and contrast kinetics in bolus-timed carotid magnetic resonance angiography (MRA) and interprets the findings by Fourier-based numerical modelling. One hundred patients prone to carotid stenosis were studied using contrast-enhanced carotid MRA with bolus timing. The carotid MRAs were timed to start relatively early without accounting for the injection time of the contrast medium. For interpretation different starting times were modelled, utilising the spectral information of the test bolus series. In the test bolus series the arterial time-to-peak showed a large 95% confidence interval of 12-27 s, indicating the need for individual MRA timing. All bolus-timed MRAs were of good diagnostic quality. The mean ({+-}SD) arterial contrast-to-noise ratio was 53.0 ({+-}12.8) and thus high, and 95% of the MRAs showed a slight venous contamination of 11.8% or less (median 5.6%). According to the Fourier-based modelling the central k-space may be acquired about 2 s before the arterial contrast peak. This results in carotid MRAs with sufficiently high arterial enhancement and little venous contamination. In conclusion, in bolus-timed carotid MRA a relatively short timing provides good arterial contrast with little venous contamination, which can be explained by Fourier-based numerical modelling of the contrast kinetics. (orig.)

  11. Conditions of viscosity measurement for detecting irradiated peppers

    Science.gov (United States)

    Hayashi, Toru; Todoriki, Setsuko; Okadome, Hiroshi; Kohyama, Kaoru

    1995-04-01

    Viscosity of gelatinized suspensions of black and white peppers decreased depending upon dose. The viscosity was influenced by gelatinization and viscosity measurement conditions. The difference between unirradiated pepper and an irradiated one was larger at a higher pH and temperature for gelatinization. A viscosity parameter normalized with the starch content of pepper sample and the viscosity of a 5% suspension of corn starch could get rid of the influence of the conditions for viscosity measurement such as a type of viscometer, shear rate and temperature.

  12. The effect of viscosity on impact cratering and possible application to the icy satellites of Saturn and Jupiter

    Science.gov (United States)

    Fink, J.; Gault, D.; Greeley, R.

    1984-01-01

    Impact experiments in Newtonian fluids with a range of viscosities of 0.001 to 60 Pa s demonstrate that transient crater volume and shape depend on target viscosity as well as on gravity. Volume is reduced, and depth-to-diameter ratio is increased for cratering events in which viscosity plays a dominant role. In addition to being affected by target kinematic viscosity, viscous scaling is most strongly influenced by projectile diameter, less strongly by projectile velocity, and least strongly by gravity. In a planetary context, viscous effects can occur for craters formed by small or slow moving impacting bodies, low planetary surface densities, high surface viscosities, and low gravity values; conditions all likely for certain impacts into the icy satellites of Saturn and Jupiter, especially if liquid mantles were still present beneath solid crusts. Age dating based on crater counts and size-frequency distributions for these icy bodies may have to be modified to account for the possibility that viscosity-dominated craters were initially smaller and deeper than their gravity-controlled counterparts.

  13. 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...

  14. 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)

  15. 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 $\

  16. 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...

  17. 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...

  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. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. The Effect of Exercise on Salivary Viscosity

    Directory of Open Access Journals (Sweden)

    Antoon J. M. Ligtenberg

    2016-11-01

    Full Text Available A common experience after exercise is the presence of a thick and sticky saliva layer on the oral surfaces, which causes a feeling of a dry mouth. Since the salivary mucin MUC5B is responsible for the visco-elastic behavior of saliva, in the present study we explored the effect of exercise on both the salivary viscosity and the secretion of MUC5B in saliva. Twenty healthy dental students performed an aerobic exercise by cycling for 15 min on cycle-ergometers at a heart rate of 130–140 beats per minute. Saliva was collected at three time points: before exercise, immediately after exercise and after 30 min recovery. Salivary flow rate, viscosity, amylase activity, total protein, carbohydrate and MUC5B concentration were determined. Salivary flow rate, protein and amylase did not change significantly. Immediately after exercise, the salivary viscosity and carbohydrate concentration were significantly higher than at baseline and after 30 min recovery. Immediately after exercise, the MUC5B concentration was significantly higher than after 30 min recovery. It is concluded that the presence of thick saliva after exercise is at least partially due to an increased secretion of MUC5B.

  5. 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.

  6. 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.

  7. 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

  8. A prospective, randomized, blinded-endpoint, controlled study - continuous epidural infusion versus programmed intermittent epidural bolus in labor analgesia

    Directory of Open Access Journals (Sweden)

    Joana Nunes

    Full Text Available Abstract Background: There is evidence that administration of a programmed intermittent epidural bolus (PIEB compared to continuous epidural infusion (CEI leads to greater analgesia efficacy and maternal satisfaction with decreased anesthetic interventions. Methods: In this study, 166 women with viable pregnancies were included. After an epidural loading dose of 10 mL with Ropivacaine 0.16% plus Sufentanil 10 µg, parturient were randomly assigned to one of three regimens: A - Ropivacaine 0.15% plus Sufentanil 0.2 µg/mL solution as continuous epidural infusion (5 mL/h, beginning immediately after the initial bolus; B - Ropivacaine 0.1% plus Sufentanil 0.2 µg/mL as programmed intermittent epidural bolus and C - Same solution as group A as programmed intermittent epidural bolus. PIEB regimens were programmed as 10 mL/h starting 60 min after the initial bolus. Rescue boluses of 5 mL of the same solution were administered, with the infusion pump. We evaluated maternal satisfaction using a verbal numeric scale from 0 to 10. We also evaluated adverse, maternal and neonatal outcomes. Results: We analyzed 130 pregnants (A = 60; B = 33; C = 37. The median verbal numeric scale for maternal satisfaction was 8.8 in group A; 8.6 in group B and 8.6 in group C (p = 0.83. We found a higher caesarean delivery rate in group A (56.7%; p = 0.02. No differences in motor block, instrumental delivery rate and neonatal outcomes were observed. Conclusions: Maintenance of epidural analgesia with programmed intermittent epidural bolus is associated with a reduced incidence of caesarean delivery with equally high maternal satisfaction and no adverse outcomes.

  9. SU-E-T-298: Dosimetric Assessment of Using Brass Mesh Bolus with High Energy X-Ray Beams

    Energy Technology Data Exchange (ETDEWEB)

    Manger, R; Yock, A; Soultan, D; Harry, T; Cervino, L [University of California, San Diego, La Jolla, CA (United States)

    2015-06-15

    Purpose: Brass mesh bolus has been shown to be an acceptable substitute for tissue equivalent bolus to increase superficial dose for 6 MV chest wall tangent plans. It may be advantageous to deliver a portion of the treatment using higher energy beams to decrease dose heterogeneity. The purpose of this study is to investigate the photoneutron production and activation of brass mesh bolus by high energy x-ray beams. Methods: MCNPX was used to determine brass mesh photoneutron energy spectrum and PDDs for 15 MV and 24 MV beams. PDD and photoneutron spectra were determined with and without photoneutron production to assess the contribution of photoneutrons to CAX dose. Brass mesh was placed on a solid water slab phantom and irradiated with 500 MU of 15 MV photons at 100cm SSD. A Geiger-Mueller counter was used to record counts in 10-second intervals for 30 minutes. A survey meter was used to estimate dose on contact immediately following irradiation. Results: The thickness of brass mesh bolus for MCNPX simulation was 0.4 mm. The PDDs with and without photoneutron production were statistically equivalent (i.e. the increase in neutron dose at the central axis is insignificant). Using ICRP 103 dose conversion coefficients, the increase in effective dose from en-face delivery of 300 MU was 0.047 mSv for 15 MV and 0.525 mSV for 24 MV. The dose rate on contact after the 500 MU irradiation was 0.4 mrem/hr. The effective half-life was estimated to approximately 6 minutes. Conclusion: The use of brass mesh bolus with high energy beams does not significantly affect central axis PDD. The use of a 24 MV beam with brass bolus results in nearly 10 times the increase in effective dose as with 15 MV. The activation products produced by brass bolus have an effective half-life of approximately 6 minutes.

  10. Time course of expiratory propofol after bolus injection as measured by ion molecule reaction mass spectrometry.

    Science.gov (United States)

    Hornuss, Cyrill; Wiepcke, Dirk; Praun, Siegfried; Dolch, Michael E; Apfel, Christian C; Schelling, Gustav

    2012-04-01

    Propofol in exhaled breath can be detected and monitored in real time by ion molecule reaction mass spectrometry (IMR-MS). In addition, propofol concentration in exhaled breath is tightly correlated with propofol concentration in plasma. Therefore, real-time monitoring of expiratory propofol could be useful for titrating intravenous anesthesia, but only if concentration changes in plasma can be determined in exhaled breath without significant delay. To evaluate the utility of IMR-MS during non-steady-state conditions, we measured the time course of both expiratory propofol concentration and the processed electroencephalography (EEG) as a surrogate outcome for propofol effect after an IV bolus induction of propofol. Twenty-one patients scheduled for routine surgery were observed after a bolus of 2.5 mg kg(-1) propofol for induction of anesthesia. Expiratory propofol was measured using IMR-MS and the cerebral propofol effect was estimated using the bispectral index (BIS). Primary endpoints were time to detection of expiratory propofol and time to onset of propofol's effect on BIS, and the secondary endpoint was time to peak effect (highest expiratory propofol or lowest BIS). Expiratory propofol and changes in BIS were first detected at 43 ± 21 and 49 ± 11 s after bolus injection, respectively (P = 0.29). Peak propofol concentrations (9.2 ± 2.4 parts-per-billion) and lowest BIS values (23 ± 4) were reached after 208 ± 57 and 219 ± 62 s, respectively (P = 0.57). Expiratory propofol concentrations measured by IMR-MS have similar times to detection and peak concentrations compared with propofol effect as measured by the processed EEG (BIS). This suggests that expiratory propofol concentrations may be useful for titrating intravenous anesthesia.

  11. Recombinant human interleukin-3: pharmacokinetics after intravenous and subcutaneous bolus injection and effects on granulocyte kinetics.

    Science.gov (United States)

    Hovgaard, D J; Folke, M; Mortensen, B T; Nissen, N I

    1994-08-01

    The pharmacokinetics of E. coli derived recombinant human interleukin-3 (rhIL-3) was studied following intravenous (i.v.) and subcutaneous (s.c.) bolus injection of rhIL-3. After i.v. bolus injection in eight patients, serum peak levels of 34.5-135.0 ng/ml were reached, followed by a rapid decline with a t1/2 alpha of 17 +/- 2 min and a t1/2 beta of 59 +/- 7 min. After s.c. bolus injection in five patients, the absorption was more prolonged with peak serum levels reached at 2.8 +/- 0.4 h. Elimination was also more protracted, and serum base-line levels were reached at 14-24 h. The immediate effect of rhIL-3 on peripheral white blood cells was less pronounced and more variable than previously found for G- or GM-CSF. Following i.v. administration, neutrophils showed a moderate drop to median 64% of initial values (range 42-85%) at median 30 min after injection (range 15-60 min) followed by an increase at 24 h to 69-288% of initial values. Eosinophils dropped to a median nadir of 34% and then gradually increased to maximum values in the range 135-720% at 18-24 h. The effect of rhIL-3 was further examined following i.v. injection of autologous 111Indium-labelled granulocytes in six patients. In steady state, i.v. injection of rhIL-3 caused a moderate drop in 111Indium activity of peripheral blood within 20 min without tendency to subsequent recovery. No change occurred in the activity recorded over the lungs and liver. The activity over the spleen decreased moderately in two patients. These results are strikingly different from those previously obtained after i.v. injection of rhGM-CSF.

  12. Prevalence of eosinophilic oesophagitis in adults presenting with oesophageal food bolus obstruction

    Institute of Scientific and Technical Information of China (English)

    Neel; Heerasing; Shok; Yin; Lee; Sina; Alexander; Damian; Dowling

    2015-01-01

    AIM: To look at the relationship between eosinophilic oesophagitis(EO) and food bolus impaction in adults. METHODS: We retrospectively analysed medical records of 100 consecutive patients who presented to our hospital with oesophageal food bolus obstruction(FBO) between 2012 and 2014. In this cohort, 96 were adults(64% male), and 4 paediatric patients were excluded from the analysis as our centre did not have paediatric gastroenterologists. Eighty-five adult patients underwent emergency gastroscopy. The food bolus was either advanced into the stomach using the push technique or retrieved using a standard retrieval net. Biopsies were obtained in 51 patients from the proximal and distal parts of the oesophagus at initial gastroscopy. All biopsy specimens were assessed and reviewed by dedicated gastrointestinal pathologists at the Department of Pathology, University Hospital Geelong. The diagnosis of EO was defined and established by the presence of the following histological features:(1) peak eosinophil counts > 20/hpf;(2) eosinophil microabscess;(3) superficial layering of eosinophils;(4) extracellular eosinophil granules;(5) basal cell hyperplasia;(6) dilated intercellular spaces; and(7) subepithelial or lamina propria fibrosis. The histology results of the biopsy specimens were accessed from the pathology database of the hospital and recorded for analysis. RESULTS: Our cohort had a median age of 60. Seventeen/51(33%) patients had evidence of EO on biopsy findings. The majority of patients with EO were male(71%). Classical endoscopic features of oesophageal rings, furrows or white plaques and exudates werefound in 59% of patients with EO. Previous episodes of FBO were present in 12/17 patients and 41% had a history of eczema, hay fever or asthma. Reflux oesophagitis and benign strictures were found in 20/34 patients who did not have biopsies. CONCLUSION: EO is present in approximately one third of patients who are admitted with FBO. Biopsies should be performed

  13. Intraoperative imaging of cortical perfusion by time-resolved thermography using cold bolus approach

    Science.gov (United States)

    Hollmach, Julia; Schnabel, Christian; Hoffmann, Nico; Radev, Yordan; Sobottka, Stephan; Kirsch, Matthias; Schackert, Gabriele; Koch, Edmund; Steiner, Gerald

    2014-03-01

    During the past decade, thermographic cameras with high thermal and temporal resolution of up to 30 mK and 50 Hz, respectively, have been developed. These camera systems can be used to reveal thermal variations and heterogeneities of tissue and blood. Thus, they provide a fast, sensitive, noninvasive, and label-free application to investigate blood perfusion and to detect perfusion disorders. Therefore, time-resolved thermography is evaluated and tested for intraoperative imaging of the cerebral cortex during neurosurgeries. The motivation of this study is the intraoperative evaluation of the cortical perfusion by observing the temporal temperature curve of the cortex during and after the intravenous application of a cold bolus. The temperature curve caused by a cold bolus is influenced by thermodilution, depending on the temperature difference to the patient's circulation, and the pattern of mixing with the patient's blood. In this initial study, a flow phantom was used in order to determine the temperature variations of cold boli under stable conditions in a vascular system. The typical temperature profile of cold water passing by can be approximated by a bi- Gaussian function involving a set of four parameters. These parameters can be used to assess the cold bolus, since they provide information about its intensity, duration and arrival time. The findings of the flow phantom can be applied to thermographic measurements of the human cortex. The results demonstrate that time-resolved thermographic imaging is a suitable method to detect cold boli not only at a flow phantom but also at the human cortex.

  14. SU-E-T-275: Dose Build Up and Bolusing Characteristics for Total Body Irradiation Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Butson, M; Pope, D; Whitaker, M [Chris O’Brien LifeHouse, Sydney, NSW (Australia)

    2015-06-15

    Purpose: Total Body Irradiation (TBI) treatments are mainly used in a preparative regimen for haematopoietic stem cell (or bone marrow) transplantation. Our standard regimen is a 12 Gy / 6 fraction bi-daily technique. To evaluate the delivered dose homogeneity to the patient, EBT3 Gafchromic film is positioned at the head, neck, chest, pelvis and groin for all fractions. This work investigates and quantifies the build-up dose characteristics at TBI distances and requirements for in-vivo dosimetry bolusing. Methods: Percentage dose build up characteristics of photon beams have been investigated at large extended SSD’s using parallel plate ionisations chambers (Attix) and EBT3 Gafchromic film. Measurements were made to open fields at different field sizes as well as large 40cm × 40cm fields with differing scatter conditions such as the introduction of standard Perspex scattering plates at different distances to the measurement point. Results: Percentage surface dose measured values for open fields at 300 cm SSD were found to range from 20 % up to 65.5 % for fields of 5 cm × 5 cm to 40 cm × 40 cm. With the introduction of 1cm Perspex scattering plates used in TBI treatments the surface dose values increased up to 83% to 90%, depending on the position of the Perspex scattering plate compared to the measurement point. Our work showed that at least 3mm water equivalent bolus / scatter material should be placed over the EBT3 for accurate dose assessment for TBI treatments. Conclusion: Build up dose characteristics exist at long (300cm) SSD’s including treatments using Perspex scattering plates placed at various distances form the patient during TBI treatment. Top accurately assess the applied dose during treatment, in-vivo dosimeters such as Gafchromic EBT3 should have at least 3mm bolus / scatter material placed over them to measure actual applied doses.

  15. 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

  16. 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.

  17. 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.

  18. Dosing of Milrinone in Preterm Neonates to Prevent Postligation Cardiac Syndrome: Simulation Study Suggests Need for Bolus Infusion.

    Science.gov (United States)

    Hallik, Maarja; Tasa, Tõnis; Starkopf, Joel; Metsvaht, Tuuli

    2017-01-01

    Milrinone has been suggested as a possible first-line therapy for preterm neonates to prevent postligation cardiac syndrome (PLCS) through decreasing systemic vascular resistance and increasing cardiac contractility. The optimal dosing regimen, however, is not known. To model the dosing of milrinone in preterm infants for prevention of PLCS after surgical closure of patent ductus arteriosus (PDA). Milrinone time-concentration profiles were simulated for 1,000 subjects using the volume of distribution and clearance estimates based on one compartmental population pharmacokinetic model by Paradisis et al. [Arch Dis Child Fetal Neonatal Ed 2007;92:F204-F209]. Dose optimization was based on retrospectively collected demographic data from neonates undergoing PDA ligation in Estonian PICUs between 2012 and 2014 and existing pharmacodynamic data. The target plasma concentration was set at 150-200 ng/ml. The simulation study used demographic data from 31 neonates who underwent PDA ligation. The median postnatal age was 13 days (range: 3-29) and weight was 760 g (range: 500-2,351). With continuous infusion of milrinone 0.33 μg/kg/min, the proportion of subjects within the desired concentration range was 0% by 3 h, 36% by 6 h, and 61% by 8 h; 99% of subjects exceeded the range by 18 h. The maximum proportion of total simulated concentrations in the target range was attained with a bolus infusion of 0.73 μg/kg/min for 3 h followed by a 0.16-μg/kg/min maintenance infusion. Mathematical simulations suggest that in preterm neonates the plasma time-concentration profile of milrinone can be optimized with a slow loading dose followed by maintenance infusion. © 2016 S. Karger AG, Basel.

  19. An Adaptive Nonlinear Basal-Bolus Calculator for Patients With Type 1 Diabetes

    DEFF Research Database (Denmark)

    Boiroux, Dimitri; Aradóttir, Tinna Björk; Nørgaard, Kirsten;

    2017-01-01

    to the accuracy of such calculators. Method : We propose a method based on a continuous-discrete unscented Kalman filter to continuously track the postprandial glucose dynamics and the insulin sensitivity. We augment the Medtronic Virtual Patient (MVP) model to simulate noise-corrupted data from a continuous...... glucose monitor (CGM). The basal rate is determined by calculating the steady state of the model and is adjusted once a day before breakfast. The bolus size is determined by optimizing the postprandial glucose values based on an estimate of the insulin sensitivity and states, as well as the announced meal...

  20. Continuous infusion or bolus injection of loop diuretics for congestive heart failure?

    Science.gov (United States)

    Zepeda, Patricio; Rain, Carmen; Sepúlveda, Paola

    2016-04-22

    Loop diuretics are widely used in acute heart failure. However, there is controversy about the superiority of continuous infusion over bolus administration. Searching in Epistemonikos database, which is maintained by screening 30 databases, we identified four systematic reviews including 11 pertinent randomized controlled trials overall. We combined the evidence using meta-analysis and generated a summary of findings following the GRADE approach. We concluded continuous administration of loop diuretics probably reduces mortality and length of stay compared to intermittent administration in patients with acute heart failure.

  1. Comparison of continuous epidural infusion and programmed intermittent epidural bolus in labor analgesia

    Directory of Open Access Journals (Sweden)

    Lin Y

    2016-07-01

    Full Text Available Yunan Lin, Qiang Li, Jinlu Liu, Ruimin Yang, Jingchen Liu Department of Anesthesiology, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, People’s Republic of China Background: This study aims to investigate differences between continuous epidural infusion (CEI and programmed intermittent epidural bolus (IEB analgesia for the Chinese parturients undergoing spontaneous delivery and to approach their safety to parturients and neonates.Methods: Two hundred healthy American Society of Anesthesiologists class I or II, term (≥37 weeks’ gestation, nulliparous women who requested analgesia for labor were recruited. Epidural analgesia was initiated with a solution of 0.15% ropivacaine 10 mL and maintained with 0.1% ropivacaine mixed with sufentanil 0.3 µg/mL by CEI at a rate of 5 mL/h combined with a patient-controlled epidural analgesia (PCEA bolus of 5 mL of ropivacaine sufentanil mixture or IEB of 5 mL of ropivacaine sufentanil mixture combined with a PCEA bolus of 5 mL of ropivacaine sufentanil mixture. The lockout interval was 20 minutes in each arm between the CEI and the IEB group. After 20 minutes of first dosage, visual analog scale (VAS score was obtained every 60 minutes. The maternal and fetal outcome and total consumption of analgesic solution were compared.Results: There was no difference in demographic characteristics, duration of first and second stages, delivery methods, sensory block, fetal Apgar scores, and the maternal outcomes between the CEI and IEB groups. There was a significant difference in VAS scores and epidural ropivacaine total consumption between the two groups (IEB vs CEI: 51.27±9.61 vs 70.44±12.78 mg, P<0.01. Conclusion: The use of programmed IEB mixed with PCEA improved labor analgesia compared to CEI mixed with PCEA, which could act as maintenance mode for epidural labor analgesia. Keywords: intermittent epidural bolus, continuous epidural infusion, labor analgesia, patient

  2. 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.

  3. Comparative experimental and modeling studies of the viscosity behavior of ethanol+C7 hydrocarbon mixtures versus pressure and temperature

    DEFF Research Database (Denmark)

    Zeberg-Mikkelsen, Claus Kjær; Watson, G.; Baylaucq, A.

    2006-01-01

    measured with a classical capillary viscometer (Ubbelohde) with an uncertainty of +/- 1%. A total of 208 experimental datapoints are reported. The viscosity behavior of this binary system is interpreted as the results of changes in the free volume, and the breaking or weakening of hydrogen bonds...... viscosity models with a physical and theoretical background. The evaluated models are based on the hard-sphere scheme, the concepts of the free-volume and the friction theory, and a model derived from molecular dynamics. In addition to these models, the simple compositional models by Grunberg......-Nissan and Katti-Chaudhri have also been applied. Overall a satisfactory representation of the viscosity of these two binary ethanol + C-7 hydrocarbon systems is found for the different models within the considered T, P range taking into account their simplicity....

  4. Nanostructures study of CNT nanofluids transport with temperature-dependent variable viscosity in a muscular tube

    Science.gov (United States)

    Akbar, Noreen Sher; Abid, Syed Ali; Tripathi, Dharmendra; Mir, Nazir Ahmed

    2017-03-01

    The transport of single-wall carbon nanotube (CNT) nanofluids with temperature-dependent variable viscosity is analyzed by peristaltically driven flow. The main flow problem has been modeled using cylindrical coordinates and flow equations are simplified to ordinary differential equations using long wavelength and low Reynolds' number approximation. Analytical solutions have been obtained for axial velocity, pressure gradient and temperature. Results acquired are discussed graphically for better understanding. It is observed that with an increment in the Grashof number the velocity of the governing fluids starts to decrease significantly and the pressure gradient is higher for pure water as compared to single-walled carbon nanotubes due to low density. As the specific heat is very high for pure water as compared to the multi-wall carbon nanotubes, it raises temperature of the muscles, in the case of pure water, as compared to the multi-walled carbon nanotubes. Furthermore, it is noticed that the trapped bolus starts decreasing in size as the buoyancy forces are dominant as compared to viscous forces. This model may be applicable in biomedical engineering and nanotechnology to design the biomedical devices.

  5. High-resolution manometric evaluation of the effects of cisapride on the esophagus during administration of solid and liquid boluses in awake healthy dogs.

    Science.gov (United States)

    Ullal, Tarini V; Kass, Philip H; Conklin, Jeffrey L; Belafsky, Peter C; Marks, Stanley L

    2016-08-01

    OBJECTIVE To validate the use of high-resolution manometry (HRM) in awake, healthy dogs and compare the effects of bolus type (liquid vs solid) and drug treatment (saline [0.9% NaCl] solution [SS] vs cisapride) on esophageal pressure profiles. ANIMALS 8 healthy dogs. PROCEDURES In a crossover study, each dog received SS (10 mL) IV, and HRM was performed during oral administration of 10 boluses (5 mL each) of water or 10 boluses (5 g each) of canned food. Cisapride (1 mg/kg in 60 mL of SS) was subsequently administered IV to 7 dogs; HRM and bolus administration procedures were repeated. Two to 4 weeks later, HRM was repeated following administration of SS and water and food boluses in 4 dogs. Pressure profile data were obtained for all swallows, and 11 outcome variables were statistically analyzed. RESULTS After SS administration, predicted means for the esophageal contractile integral were 850.4 cm/mm Hg/s for food boluses and 660.3 cm/mm Hg/s for water boluses. Predicted means for esophageal contraction front velocity were 6.2 cm/s for water boluses and 5.6 cm/s for food boluses after SS administration. Predicted means for residual LES pressure were significantly higher following cisapride administration. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that HRM was feasible and repeatable in awake healthy dogs of various breeds and sizes. Stronger esophageal contractions and faster esophageal contraction velocity occurred during solid bolus and liquid bolus swallows, respectively. Lower esophageal sphincter pressure increased significantly following cisapride administration. Esophageal contractions and bolus transit latency should be further evaluated by HRM in clinically dysphagic dogs.

  6. 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.

  7. 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.

  8. Comparison of the effects of xylazine bolus versus medetomidine constant rate infusion on the stress response, urine production, and anesthetic recovery characteristics in horses anesthetized with isoflurane.

    Science.gov (United States)

    Creighton, Catherine M; Lemke, Kip A; Lamont, Leigh A; Horney, Barbara S; Doyle, Aimie J

    2012-04-15

    To compare the effect of xylazine bolus versus medetomidine constant rate infusion (MCRI) on serum cortisol and glucose concentrations, urine production, and anesthetic recovery characteristics in dorsally recumbent, spontaneously breathing, isoflurane-anesthetized horses. Prospective, randomized crossover study. 10 healthy Standardbreds. Horses were premedicated with xylazine or medetomidine IV. Anesthesia was induced with diazepam and ketamine and maintained with isoflurane for 150 minutes. For the xylazine treatment, end-tidal isoflurane concentration was maintained at 1.7% and xylazine (0.2 mg/kg [0.09 mg/lb]), IV) was administered as a bolus at the end of anesthesia. For the MCRI treatment, end-tidal isoflurane concentration was maintained at 1.4% and medetomidine (0.005 mg/kg/h [0.0023 mg/lb/h], IV) was infused throughout anesthesia. Serum cortisol and glucose concentrations were measured before, during, and after anesthesia. Urine specific gravity and volume were measured during anesthesia. Unassisted anesthetic recoveries were recorded by a digital video camera for later evaluation by 2 observers who were blinded to treatment. Serum cortisol concentration was lower and serum glucose concentration was higher with MCRI treatment, compared with xylazine treatment. Time to sternal recumbency was longer with MCRI treatment, but no difference was seen between treatments for times to extubation, first movement, or standing. Objective (mean attempt interval) and subjective (visual analog score) recovery scores were significantly better with MCRI treatment, compared with xylazine treatment. In isoflurane-anesthetized horses, premedication and administration of medetomidine as a constant rate infusion resulted in decreased serum cortisol concentration, increased serum glucose concentration, and superior anesthetic recovery characteristics, compared with conventional treatment with xylazine.

  9. Comparative experimental and modeling studies of the viscosity behavior of ethanol+C7 hydrocarbon mixtures versus pressure and temperature

    DEFF Research Database (Denmark)

    Zeberg-Mikkelsen, Claus Kjær; Watson, G.; Baylaucq, A.;

    2006-01-01

    viscosity models with a physical and theoretical background. The evaluated models are based on the hard-sphere scheme, the concepts of the free-volume and the friction theory, and a model derived from molecular dynamics. In addition to these models, the simple compositional models by Grunberg...

  10. Note: Utilization of polymer gel as a bolus compensator and a dosimeter in the near-surface buildup region for breast-conserving therapy

    Energy Technology Data Exchange (ETDEWEB)

    Fuse, Hiraku, E-mail: fuseh@ipu.ac.jp; Inohira, Masaya; Kawamura, Hiraku; Fujisaki, Tatsuya [Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, Inashiki-gun, Ibaraki 300-0331 (Japan); Shinoda, Kazuya [Graduate School of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, Ibaraki (Japan); Department of Radiological Technology, Tsukuba Medical Center Hospital, Tsukuba (Japan); Miyamoto, Katsumi [Department of Radiological Technology, Tsukuba Medical Center Hospital, Tsukuba (Japan); Sakae, Takeji [Faculty of Medicine, University of Tsukuba, Tsukuba (Japan)

    2015-09-15

    Tangential beam radiotherapy is routinely used for radiation therapy after breast conserving surgery. A tissue-equivalent bolus placed on the irradiated area shifts the depth of the dose distribution; this bolus provides uniform dose distribution to the breast. The gel bolus made by the BANG-Pro{sup ®} polymer gel and in an oxygen non-transmission pack was applicable as a dosimeter to measure dose distribution in near-surface buildup region. We validated the use of the gel bolus to improve in the whole-breast/chest wall, including the near-surface buildup region.

  11. Bolus timing in high-pitch CT angiography of the aorta

    Energy Technology Data Exchange (ETDEWEB)

    Beeres, Martin, E-mail: beeres@gmx.net [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Loch, Matthias, E-mail: MatthiasLoch@gmx.net [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Schulz, Boris, E-mail: boris.schell@googlemail.com [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Kerl, Matthias, E-mail: matthias.kerl@gmail.com [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Al-Butmeh, Firas, E-mail: Firas.Albutmeh@gmail.com [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Bodelle, Boris, E-mail: bbodelle@googlemail.com [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Herrmann, Eva, E-mail: Herrmann@Med.Uni-Frankfurt.de [Clinic of the Goethe University, Department of Biostatistics, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Gruber-Rouh, Tatjana, E-mail: tatjanagruber2004@yahoo.de [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Lee, Clara, E-mail: Clara.Lee@kgu.de [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Jacobi, Volkmar, E-mail: Volkmar.Jacobi@kgu.de [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Vogl, Thomas J., E-mail: T.Vogl@em.uni-frankfurt.de [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); and others

    2013-06-15

    Objective: To investigate the bolus geometry in high-pitch CT angiography (CTA) of the aorta without ECG synchronisation in comparison to single-source CT. Methods: Overall 160 consecutive patients underwent CTA either in conventional single-source mode with a pitch of 1.2 (group 1), or in dual-source mode with a pitch of 3.0 (groups 2, 3 and 4) using different contrast media timings with bolus triggering at 140 HU (5 s, group 1; 10 s, group 2; 12 s, group 3; 14 s, group 4). Contrast material, saline flush, flow rate and kV/mAs settings were kept equal for optimum comparability. Aortic attenuation was measured along the z-axis of the patient at different anatomic landmarks and subjective image quality was compared. Results: The most homogeneous enhancement of the aorta was reached with a delay of 10 s after reaching the trigger threshold. The imaging length was not significantly different, but the examination time was significantly (p < 0.001) shorter in the high-pitch group (7.7 s vs. 1.7 s for group 1 vs. 2, 3 and 4). Conclusion: In high-pitch CT angiography using a start delay of 10 s after a trigger threshold of 140 HU in the descending aorta is reached, a homogenous contrast along the z-axis is accomplished.

  12. [Remifentanil bolus for cesarean section in high-risk patients: study of 12 cases].

    Science.gov (United States)

    Palacio, F J; Ortiz-Gómez, J R; Fornet, I; López, M A; Morillas, P

    2008-02-01

    To evaluate the utility and safety of remifentanil for hemodynamic control during cesarean section in high-risk patients ineligible for spinal anesthesia. One minute before induction we injected a bolus of 1 microg x kg(-1) of remifentanil, followed by propofol (2.5 mg x kg(-1)), succinylcholine (1 mg x kg(-1)), cisatracurium, sevoflurane in oxygen and nitrous oxide, and fentanyl (5 microg x kg(-1)) after clamping the umbilical cord. We recorded maternal hemodynamic variables, pulse oximetry, capnography, bispectral index, and presence of muscular rigidity. In the neonate we assessed fetal wellbeing, weight, and requirement for naloxone. Hemodynamic stability was defined as no more than 15% variation in arterial pressure with respect to baseline. Twelve patients undergoing surgery because of placenta abruptio, subarachnoid hemorrhage, HELLP syndrome, or preeclampsia were enrolled. Hemodynamic variables were consistently stable during surgery in all patients. No cases of neonatal rigidity were noted and there was no need for naloxone. The mean Apgar score was 6.42 (1.5) at 1 minute and 8.42 (0.9) at 5 minutes. Bolus injection of 1 microg x kg(-1) of remifentanil may be useful for maintaining maternal hemodynamic stability in high-risk obstetric cases. Given the risk of neonatal depression, this resource should be used selectively and the means for neonatal resuscitation should be available.

  13. Efficacy of Bolus-dose Phenylephrine for Peri-intubation Hypotension.

    Science.gov (United States)

    Panchal, Ashish R; Satyanarayan, Arthi; Bahadir, Jenna D; Hays, Daniel; Mosier, Jarrod

    2015-10-01

    Intubation in hypotensive emergency department (ED) patients may increase the risk of life-threatening complications such as hypoperfusion and cardiovascular collapse. Peripherally administered, diluted "push-dose" phenylephrine has been advocated to treat peri-intubation hypotension, however, its effectiveness is unknown. To investigate the efficacy and usage patterns of bolus-dose phenylephrine for peri-intubation hypotension at an academic medical center. A retrospective chart review of all adult intubated, hypotensive patients (systolic blood pressure [SBP] HR). A total of 119 patients met eligibility criteria. Phenylephrine was given to 29/119 (24%) patients and 20 (17%) were treated during the peri-intubation period. Phenylephrine was given for many different conditions, and treatment timing varied greatly. Phenylephrine was given with other vasopressors 70% of the time (14/20), however, the timing of vasopressor infusion also varied greatly. When phenylephrine was given during the peri-intubation period, there were significant increases in SBP and DBP (p HR. In this academic ED, bolus-dose phenylephrine was used by practitioners without a systematic pattern. Although phenylephrine improved hemodynamics, it is possible that nonsystematic use of phenylephrine may cause inadvertent negative effects. Further studies will need to be conducted to better understand the best practices for use of phenylephrine. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Utility of a New Bolus-injectable Nanoparticle for Clinical Cancer Staging

    Directory of Open Access Journals (Sweden)

    Mukesh Harisinghani

    2007-12-01

    Full Text Available BACKGROUND: In this study, we report on the use of a new, bolus-injectable, carboxymethyl dextran-based magnetic nanoparticle (MNP, ferumoxytol, to improve detection in loco-regional lymph nodes by magnetic resonance imaging (MRI. Methods: This preliminary study was performed as a prospective, single-center, open label pilot study to determine the magnitude of nodal MRI signal changes and to determine the optimal time points for imaging following intravenous (IV bolus injection of the MNP. The study group consisted of 10 patients, all of whom were diagnosed with prostate cancer before any systemic therapy. RESULTS: All 10 patients had lymph nodes evaluated by histopathology. Of the evaluated 26 lymph nodes, 20 were benign and 6 were malignant. The mean short-axis diameter of benign lymph nodes was 6 mm and the mean short-axis diameter of malignant lymph nodes was 7 mm. Following IV administration, there was a significant change in mean signal-to-noise ratio (SNR of benign lymph nodes (P < .0001 whereas there was little change in the mean SNR of malignant nodes (P = .1624. No adverse events were encountered. CONCLUSION: Ferumoxytol is safe and, at the appropriate circulation interval, modulates nodal signal intensity, allowing for identification of malignant nodal involvement by MRI.

  15. Peristaltic Transport of a Rheological Fluid: Model for Movement of Food Bolus Through Esophagus

    CERN Document Server

    Misra, J C

    2011-01-01

    Fluid mechanical peristaltic transport through esophagus has been of concern in the paper. A mathematical model has been developed with an aim to study the peristaltic transport of a rheological fluid for arbitrary wave shapes and tube lengths. The Ostwald-de Waele power law of viscous fluid is considered here to depict the non-Newtonian behaviour of the fluid. The model is formulated and analyzed with the specific aim of exploring some important information concerning the movement of food bolus through the esophagus. The analysis has been carried out by using lubrication theory. The study is particularly suitable for cases where the Reynolds number is small. The esophagus is treated as a circular tube through which the transport of food bolus takes places by periodic contraction of the esophageal wall. Variation of different variables concerned with the transport phenomena such as pressure, flow velocity, particle trajectory and reflux are investigated for a single wave as well as for a train of periodic per...

  16. Oscillation and collective conveyor of water-in-oil droplets by microfluidic bolus flow

    CERN Document Server

    Ohmura, Takuya; Kamei, Ken-ichiro; Maeda, Yusuke T

    2015-01-01

    Microfluidic techniques have been extensively developed to realize micro-total analysis systems in a small chip. For microanalysis, the trapping or arranging of objects in a line is a critical step. Physical effects such as inertial lift force have been utilized so far, however, hydrodynamic interaction in a many body system is yet to be explored despite its relevance to pattern formation. Here, we report water-in-oil (W/O) droplets can be transported with sequential order in the grid of one-dimensional array of another large W/O droplets. As each droplet comes close to an interspace of the large droplet array, while exhibiting persistent back-and-forth motion, it is conveyed at a velocity equal to the droplet array. The droplet also makes asymmetric orbit to and from the large droplet behind, suggesting vortex like stream was involved. We confirm the appearance of closed streamlines, which called bolus flow, in numerical simulation based on lattice Boltzmann method. The existence region of bolus flow account...

  17. Cerebral perfusion imaging with bolus harmonic imaging (Honorable Mention Poster Award)

    Science.gov (United States)

    Kier, Christian; Toth, Daniel; Meyer-Wiethe, Karsten; Schindler, Angela; Cangur, Hakan; Seidel, Gunter; Aach, Til

    2005-04-01

    Fast visualisation of cerebral microcirculation supports diagnosis of acute stroke. However, the commonly used CT/MRI-based methods are time consuming, costly and not applicable to every patient. The bolus perfusion harmonic imaging (BHI) method is an ultrasound imaging technique which makes use of the fact, that ultrasound contrast agents unlike biological tissues resonate at harmonic frequencies. Exploiting this effect, the contrast between perfused and non-perfused areas can be improved. Thus, BHI overcomes the low signal-to-noise ratio of transcranial ultrasound and the high impedance of the skull. By analysing image sequences, visualising the qualitative characteristics of an US contrast agent bolus injection becomes possible. The analysis consists of calculating four perfusion-related parameters, Local Peak Intensity, Time To Peak, Area Under Curve, and Average Rising, from the time/intensity curve and providing them as colour-coded images. For calculating these parameters the fundamental assumption is that image intensity corresponds to contrast agent concentration which in turn shows the perfusion of the corresponding brain region. In a clinical study on patients suffering from acute ischemic stroke it is shown that some of the parameters correlate significantly to the infarction area. Thus, BHI becomes a less time-consuming and inexpensive bedside method for diagnosis of cerebral perfusion deficits.

  18. Quantitative myocardial perfusion magnetic resonance imaging: the impact of pulsatile flow on contrast agent bolus dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Graafen, Dirk; Hamer, Julia; Weber, Stefan; Schreiber, Laura M, E-mail: graafen@uni-mainz.de [Section of Medical Physics, Department of Radiology, Johannes Gutenberg University Medical Center, Mainz (Germany)

    2011-08-21

    Myocardial blood flow (MBF) can be quantified using T{sub 1}-weighted first-pass magnetic resonance imaging (MRI) in combination with a tracer-kinetic model, like MMID4. This procedure requires the knowledge of an arterial input function which is usually estimated from the left ventricle (LV). Dispersion of the contrast agent bolus may occur between the LV and the tissue of interest. The aim of this study was to investigate the dispersion under conditions of physiological pulsatile blood flow, and to simulate its effect on MBF quantification. The dispersion was simulated in coronary arteries using a computational fluid dynamics (CFD) approach. Simulations were accomplished on straight vessels with stenosis of different degrees and shapes. The results show that dispersion is more pronounced under resting conditions than during hyperemia. Stenosis leads to a reduction of dispersion. In consequence, dispersion results in a systematic MBF underestimation between -0.4% and -9.3%. The relative MBF error depends not only on the dispersion but also on the actual MBF itself. Since MBF under rest is more underestimated than under stress, myocardial perfusion reserve is overestimated between 0.1% and 4.5%. Considering other sources of errors in myocardial perfusion MRI, systematic errors of MBF by bolus dispersion are relatively small.

  19. Magnetic nanofluid natural convection in the presence of thermal radiation considering variable viscosity

    Science.gov (United States)

    Sheikholeslami, Mohsen; Rokni, Houman B.

    2017-05-01

    Magnetohydrodynamic nanofluid flow and convective heat transfer are studied considering thermal radiation. Effects of magnetic field and shape of nanoparticles on viscosity and thermal conductivity of the nanofluid are taken into account. The solutions of final equations are obtained by the control volume-based finite-element method (CVFEM). Roles of shape of nanoparticles, radiation parameter, ferrofluid volume fraction, Hartmann and Rayleigh numbers are presented graphically. Results demonstrate that selecting the Platelet shape for Fe3O4 nanoparticles leads to maximum Nusselt number. Rate of heat transfer increases with increasing Rayleigh number and radiation parameter but it decreases with increasing Hartmann number.

  20. Electron treatment of wood pulp for the viscose process

    Science.gov (United States)

    Stepanik, T. M.; Ewing, D. E.; Whitehouse, R.

    2000-03-01

    Electron processing is currently being evaluated by several viscose producers for integration into their process. The viscose industry converts dissolving wood pulp into products such as staple fibre, filament, cord, film, packaging, and non-edible sausage casings. These materials are used in the clothing, drapery, hygiene, automobile, food, and packaging industries. Viscose producers are facing increasingly high production costs and stringent environmental regulations that have forced some plants to close. Electron treatment of wood pulp can significantly reduce the amounts of chemicals used for producing viscose and the production of hazardous pollutants. Acsion Industries has worked with companies worldwide to demonstrate the benefits of using electron treated pulp for producing viscose (rayon). This paper describes the viscose process, the benefits of using electron treatment in the viscose process, and Acsion's efforts in developing this technology.

  1. New Formulation for the Viscosity of Propane

    Science.gov (United States)

    Vogel, Eckhard; Herrmann, Sebastian

    2016-12-01

    A new viscosity formulation for propane, using the reference equation of state for its thermodynamic properties by Lemmon et al. [J. Chem. Eng. Data 54, 3141 (2009)] and valid in the fluid region from the triple-point temperature to 650 K and pressures up to 100 MPa, is presented. At the beginning, a zero-density contribution and one for the critical enhancement, each based on the experimental data, were independently generated in parts. The higher-density contributions are correlated as a function of the reciprocal reduced temperature τ = Tc/T and of the reduced density δ = ρ/ρc (Tc—critical temperature, ρc—critical density). The final formulation includes 17 coefficients inferred by applying a state-of-the-art linear optimization algorithm. The evaluation and choice of the primary data sets are detailed due to its importance. The viscosity at low pressures p ≤ 0.2 MPa is represented with an expanded uncertainty of 0.5% (coverage factor k = 2) for temperatures 273 ≤ T/K ≤ 625. The expanded uncertainty in the vapor phase at subcritical temperatures T ≥ 273 K as well as in the supercritical thermodynamic region T ≤ 423 K at pressures p ≤ 30 MPa is assumed to be 1.5%. In the near-critical region (1.001 < 1/τ < 1.010 and 0.8 < δ < 1.2), the expanded uncertainty increases with decreasing temperature up to 3.0%. It is further increased to 4.0% in regions of less reliable primary data sets and to 6.0% in ranges in which no primary data are available but the equation of state is valid. Tables of viscosity computed for the new formulation are given in an Appendix for the single-phase region, for the vapor-liquid phase boundary, and for the near-critical region.

  2. 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.

  3. 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.

  4. 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.

  5. Electronic identification of cattle: interference in the reading of ceramic bolus transponders in the presence of ruminal magnets

    Directory of Open Access Journals (Sweden)

    N. Ferri

    2004-01-01

    Full Text Available The authors assess the reading performances of electronic transponders encased in ceramic boluses, utilised as identification (ID instruments for production ruminants, and the possible influence of the magnet, which is located in the fore-stomach of ruminants. Research has been conducted in free-range Friesian dairy herds in the Teramo Province. The use of the electronic bolus to identify cattle appears to provide better guarantees than the traditional methods used and meets the requirements of identifying individual animals at the farm level. Results demonstrate how the presence of both the magnet and the ceramic bolus, equipped with a transponder, makes it difficult, and sometimes impossible, to read the code. However, the electronic ID system is the best instrument currently available. The authors confirm the validity of this method and highlight some problems that still need to be solved.

  6. Adaptation of a High-Pressure Liquid Chromatography System for the Measurement of Viscosity

    Directory of Open Access Journals (Sweden)

    Sonia Gregory

    2014-03-01

    Full Text Available The state-of-the-art instruments for the determination of viscosity of liquids typically require a significant amount of sample, and have relatively low throughput due to manual and sequential measurements. In this study, it was demonstrated that the pressure generated by the flow of viscous fluids through a capillary could be precisely measured employing high-pressure liquid chromatography systems (HPLC using glycerol solutions of moderate viscosity as a mobile phase, and correlated to the dynamic (absolute viscosity. The parameters allowing calculation of the viscosity of glycerol calibration standards as a function of temperature were established. The measurements were made with volumes as small as 10 μL, and the use of an autosampler permitted unattended analysis of a large number samples. The method appears to be particularly well suited for the development of viscous formulations of therapeutic, protein-based macromolecules, where the amount sample is typically limited and relatively wide ranges of conditions are considered in the optimization process. The utility of the methods was illustrated by application to the development of concentrated inactivated virus vaccines.

  7. Low-Viscosity, Radiation-Resistant Resin System with Increased Toughness

    Science.gov (United States)

    Reed, R. P.; Evans, D.

    2004-06-01

    Most radiation-resistant resin systems have relatively high viscosities and short working times (pot life) that do not permit their use for resin-transfer or vacuum pressure impregnation for the bonding of superconducting coils. Others are too expensive for practical use in either commercial coils or experimental projects that require large resin volumes. A new resin system has been developed that has low viscosities (100 mPaṡs to 250 mPaṡs) and long working times (8 h to 20 h) at 40 °C to 50 °C. The system consists of a DGEBF epoxy resin blended with PPGDGE with a DETD hardener. The ratio of DGEBF to PPGDGE can be varied to achieve desired viscosity and working time and increased resin toughness. The resin system was developed for use in the very large Atlas end-cap toroids and is also being used successfully to bond superconducting coils for commercial applications. Data on viscosity as a function of time, temperature, and DGEBF/PPGDGE blend are provided. Radiation effects (outgassing, swelling, moduli changes), low-temperature physical properties (density, elastic moduli, thermal conductivity, thermal contraction, dielectric breakdown, glass transition temperature), and low-temperature mechanical properties (shear/compression, flexure, short-beam shear) measurement results are presented.

  8. Density and Viscosity Measurement of Diesel Fuels at Combined High Pressure and Elevated Temperature

    Directory of Open Access Journals (Sweden)

    Carl Schaschke

    2013-07-01

    Full Text Available We report the measurement of the viscosity and density of various diesel fuels, obtained from British refineries, at elevated pressures up to 500 MPa and temperatures in the range 298 K to 373 K. The measurement and prediction procedures of fluid properties under high pressure conditions is of increasing interest in many processes and systems including enhanced oil recovery, automotive engine fuel injection, braking, and hydraulic systems. Accurate data and understanding of the fluid characteristic in terms of pressure, volume and temperature is required particularly where the fluid is composed of a complex mixture or blend of aliphatic or aromatic hydrocarbons. In this study, high pressure viscosity data was obtained using a thermostatically-controlled falling sinker-type high pressure viscometer to provide reproducible and reliable viscosity data based on terminal velocity sinker fall times. This was supported with density measurements using a micro-pVT device. Both high-pressure devices were additionally capable of illustrating the freezing points of the hydrocarbon mixtures. This work has, thus, provided data that can extend the application of mixtures of commercially available fuels and to test the validity of available predictive density and viscosity models. This included a Tait-style equation for fluid compressibility prediction. For complex diesel fuel compositions, which have many unidentified components, the approach illustrates the need to apply appropriate correlations, which require accurate knowledge or prediction of thermodynamic properties.

  9. Densities, Viscosities and Related Properties for Binary Mixtures of Sulfolane + p-Xylene, Sulfolane + Ethylbenzene in the Temperature Range from 303.15 K to 353.15 K%二元混合物环丁酚和对二甲苯、乙苯在温度范围为303.15-353.15K下的密度、黏度及其相关性质

    Institute of Scientific and Technical Information of China (English)

    杨长生; 马沛生; 周清

    2004-01-01

    Densities and viscosities of the binary systems of sulfolane + ethylbenzene, sulfolane + p-xylene have been experimentally determined in temperature interval 303.15-353.15 K and at atmospheric pressure for the whole composition range. The excess molar volumes and viscosity deviations were computed. The computed quantities have been fitted to Redlich-Kister equation. Excess molar volumes and viscosity deviation show a systematic change with increasing temperature. Two mixtures exhibit negative excess volumes with a minimum which occurs approximately at x = 0.5. The effect of the size, shape and interaction of components on excess molar volumes and viscosity deviations is discussed.

  10. "The relationship between pharmacokinetic variables and pharmacodynamic profiles of bolus versus continuous infusion of furosemide in critically ill patients"

    Directory of Open Access Journals (Sweden)

    "Mojtaba Mojtahedzadeh

    2005-05-01

    Full Text Available In this investigation, the pharmacokinetic variables of continuous infusion and intermittent bolus injection of furosemide and the possible relationship between its pharmacokinetic characteristics and pharmacodynamic profile among intensive care unit (ICU patients were studied. In this prospective, randomized, clinical trial, twelve patients received IV bolus of 20 mg of the drug during 3 hours period and, the drug dose was doubled, when the urine output was less than 1 ml/kg/h (group 1. The other nine patients received a continuous intravenous furosemide infusion at the rate of 0.1 mg/kg/h (group 2. The amount of furosemide in serum was measured by high performance liquid chromatography (HPLC. Results showed a positive correlation between plasma clearance of furosemide and its diuretic activity (P=0.01. The pharmacokinetic parameters such as Vd (l, CL (ml/min, Ke (min-1 and t½ (min in continuous infusion patients were not significantly differed from the bolus patients (P-values 0.5, 0.9, 0.9,0.9, respectively. Nevertheless the observed plasma clearance of drug in the continuous infusion group was clinically higher than bolus injection group and as a result the cumulative urine output per hour per mg of furosemide in a continuous infusion was observed to be higher than bolus(P=0.2. Changes in serum sodium and potassium were similar for both groups, but bolus injection patients were associated with higher potassium depletion (P=0.001. Therefore, continuous infusion seems to be better means of diuretic therapy in critically ill patients.

  11. 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 ...

  12. Viscosity bound versus the universal relaxation bound

    Science.gov (United States)

    Hod, Shahar

    2017-10-01

    For gauge theories with an Einstein gravity dual, the AdS/CFT correspondence predicts a universal value for the ratio of the shear viscosity to the entropy density, η / s = 1 / 4 π. The holographic calculations have motivated the formulation of the celebrated KSS conjecture, according to which all fluids conform to the lower bound η / s ≥ 1 / 4 π. The bound on η / s may be regarded as a lower bound on the relaxation properties of perturbed fluids and it has been the focus of much recent attention. In particular, it was argued that for a class of field theories with Gauss-Bonnet gravity dual, the shear viscosity to entropy density ratio, η / s, could violate the conjectured KSS bound. In the present paper we argue that the proposed violations of the KSS bound are strongly constrained by Bekenstein's generalized second law (GSL) of thermodynamics. In particular, it is shown that physical consistency of the Gauss-Bonnet theory with the GSL requires its coupling constant to be bounded by λGB ≲ 0 . 063. We further argue that the genuine physical bound on the relaxation properties of physically consistent fluids is ℑω(k > 2 πT) > πT, where ω and k are respectively the proper frequency and the wavenumber of a perturbation mode in the fluid.

  13. Textural perception of liquid emulsions: Role of oil content, oil viscosity and emulsion viscosity

    NARCIS (Netherlands)

    Aken, van G.A.; Vingerhoeds, M.H.; Wijk, de R.A.

    2011-01-01

    This work describes a study on the in-mouth textural perception of thickened liquid oil-in-water emulsions. The variables studied are oil content, oil viscosity, and the concentration of polysaccharide thickener. Gum arabic was chosen as the thickener because of the nearly Newtonian behavior of its

  14. 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

  15. Comparison of first pass bolus AIFs extracted from sequential {sup 18}F-FDG PET and DSC-MRI of mice

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Eleanor, E-mail: ee244@cam.ac.uk [Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0QQ (United Kingdom); Sawiak, Stephen J. [Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0QQ (United Kingdom); Behavioural and Clinical Neuroscience Institute, Department of Experimental Psychology, University of Cambridge, Cambridge, CB2 3EB (United Kingdom); Ward, Alexander O.; Buonincontri, Guido; Hawkes, Robert C.; Adrian Carpenter, T. [Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0QQ (United Kingdom)

    2014-01-11

    Accurate kinetic modelling of in vivo physiological function using positron emission tomography (PET) requires determination of the tracer time–activity curve in plasma, known as the arterial input function (AIF). The AIF is usually determined by invasive blood sampling methods, which are prohibitive in murine studies due to low total blood volumes. Extracting AIFs from PET images is also challenging due to large partial volume effects (PVE). We hypothesise that in combined PET with magnetic resonance imaging (PET/MR), a co-injected bolus of MR contrast agent and PET ligand can be tracked using fast MR acquisitions. This protocol would allow extraction of a MR AIF from MR contrast agent concentration–time curves, at higher spatial and temporal resolution than an image-derived PET AIF. A conversion factor could then be applied to the MR AIF for use in PET kinetic analysis. This work has compared AIFs obtained from sequential DSC-MRI and PET with separate injections of gadolinium contrast agent and {sup 18}F-FDG respectively to ascertain the technique′s validity. An automated voxel selection algorithm was employed to improve MR AIF reproducibility. We found that MR and PET AIFs displayed similar character in the first pass, confirmed by gamma variate fits (p<0.02). MR AIFs displayed reduced PVE compared to PET AIFs, indicating their potential use in PET/MR studies.

  16. Viscosity measurements of antibody solutions by photon correlation spectroscopy: an indirect approach - limitations and applicability for high-concentration liquid protein solutions.

    Science.gov (United States)

    Wagner, Michael; Reiche, Katharina; Blume, Alfred; Garidel, Patrick

    2013-01-01

    Photon correlation spectroscopy (PCS) is compared with classic rheological measurements using the cone-and-plate technique for the determination of the viscosity of protein solutions. The potential advantages using PCS are small sample volume and fast determination of zero-shear viscosity. The present study assesses potentials and limitations of the applicability of this method for the determination of viscosity of antibody solutions in protein science development. The principle of the assay is based on the determination of the apparent hydrodynamic radius of commercial available latex beads of known size added to protein solutions. Using the Stokes-Einstein equation, the hydrodynamic radius can be converted to viscosity. Several latex particle sizes and concentrations were evaluated and the assay optimized. The PCS assay for viscosity determination was tested using water/glycerol-mixtures, where the viscosity was measured with rheometer using the cone-and-plate method and also compared with published data. Different protein solutions of bovine serum albumin, lysozyme and monoclonal antibodies were then used and the PCS results were compared with viscosity data obtained by the cone-and-plate method. It could be shown that the PCS assay has limitations for the determination of the viscosity of protein solutions, especially monoclonal antibodies. The main reason is due to protein-latex bead interactions leading to the formation of larger aggregates. The use of surface modification of the latex beads can in principle prevent this interaction.

  17. Thermodynamic study of three pharmacologically significant drugs: Density, viscosity, and refractive index measurements at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, Muhammad Javed [Department of Chemistry, Quaid-i-Azam University, Islamabad 45320 (Pakistan)], E-mail: mjiqauchem@yahoo.com; Chaudhry, Mansoora Ahmed [Department of Chemistry, Quaid-i-Azam University, Islamabad 45320 (Pakistan)

    2009-02-15

    Measurements of density, viscosity, and refractive index of three pharmacologically significant drugs, i.e. diclofenac sodium, cetrizine, and doxycycline have been carried in aqueous medium at T = (293.15 to 313.15) K. An automated vibrating-tube densimeter, viscometer, and refractometer are used in a concentration range from (7.5) . 10{sup -3} to 25 . 10{sup -3}) mol . kg{sup -1}. The precise density results are used to evaluate the apparent molar volume, partial molar volume, thermal expansion coefficient, partial molar expansivity, and the Hepler's constant. Viscosity results are used to calculate the Jones-Dole viscosity B-coefficient, free energy of activation of the solute and solvent, activation enthalpy, and activation entropy. The molar refractive indices of the drug solutions can be employed to calculate molar refraction. It is inferred from these results that the above mentioned drugs act as structure-making compounds due to hydrophobic hydration of the molecules in the drugs.

  18. Perfusion analysis using a wide coverage flat-panel volume CT: feasibility study

    Science.gov (United States)

    Grasruck, M.; Gupta, R.; Reichardt, B.; Klotz, E.; Schmidt, B.; Flohr, T.

    2007-03-01

    We developed a Flat-panel detector based Volume CT (VCT) prototype scanner with large z-coverage. In that prototype scanner a Varian 4030CB a-Si flat-panel detector was mounted in a multi slice CT-gantry (Siemens Medical Solutions) which provides a 25 cm field of view with 18 cm z-coverage at isocenter. The large volume covered in one rotation can be used for visualization of complete organs of small animals, e.g. rabbits. By implementing a mode with continuous scanning, we are able to reconstruct the complete volume at any point in time during the propagation of a contrast bolus. Multiple volumetric reconstructions over time elucidate the first pass dynamics of a bolus of contrast resulting in 4-D angiography and potentially allowing whole organ perfusion analysis. We studied to which extent pixel based permeability and blood volume calculation with a modified Patlak approach was possible. Experimental validation was performed by imaging evolution of contrast bolus in New Zealand rabbits. Despite the short circulation time of a rabbit, the temporal resolution was sufficient to visually resolve various phases of the first pass of the contrast bolus. Perfusion imaging required substantial spatial smoothing but allowed a qualitative discrimination of different types of parenchyma in brain and liver. If a true quantitative analysis is possible, requires further studies.

  19. 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 ...

  20. 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.

  1. 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.

  2. 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...

  3. 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.

  4. Ultrafast Excited State Dynamics in Molecular Motors: Coupling of Motor Length to Medium Viscosity.

    Science.gov (United States)

    Conyard, Jamie; Stacko, Peter; Chen, Jiawen; McDonagh, Sophie; Hall, Christopher R; Laptenok, Sergey P; Browne, Wesley R; Feringa, Ben L; Meech, Stephen R

    2017-03-07

    Photochemically driven molecular motors convert the energy of incident radiation to intramolecular rotational motion. The motor molecules considered here execute four step unidirectional rotational motion. This comprises a pair of successive light induced isomerizations to a metastable state followed by thermal helix inversions. The internal rotation of a large molecular unit required in these steps is expected to be sensitive to both the viscosity of the medium and the volume of the rotating unit. In this work, we describe a study of motor motion in both ground and excited states as a function of the size of the rotating units. The excited state decay is ultrafast, highly non-single exponential, and is best described by a sum of three exponential relaxation components. The average excited state decay time observed for a series of motors with substituents of increasing volume was determined. While substitution does affect the lifetime, the size of the substituent has only a minor effect. The solvent polarity dependence is also slight, but there is a significant solvent viscosity effect. Increasing the viscosity has no effect on the fastest of the three decay components, but it does lengthen the two slower decay times, consistent with them being associated with motion along an intramolecular coordinate displacing a large solvent volume. However, these slower relaxation times are again not a function of the size of the substituent. We conclude that excited state decay arises from motion along a coordinate which does not necessarily require complete rotation of the substituents through the solvent, but is instead more localized in the core structure of the motor. The decay of the metastable state to the ground state through a helix inversion occurs 14 orders of magnitude more slowly than the excited state decay, and was measured as a function of substituent size, solvent viscosity and temperature. In this case neither substituent size nor solvent viscosity influences

  5. Bolus tracking with nanofilter-based multispectral videography for capturing microvasculature hemodynamics

    Science.gov (United States)

    Najiminaini, Mohamadreza; Kaminska, Bozena; St. Lawrence, Keith; Carson, Jeffrey J. L.

    2014-04-01

    Multispectral imaging is a highly desirable modality for material-based analysis in diverse areas such as food production and processing, satellite-based reconnaissance, and biomedical imaging. Here, we present nanofilter-based multispectral videography (nMSV) in the 700 to 950 nm range made possible by the tunable extraordinary-optical-transmission properties of 3D metallic nanostructures. Measurements made with nMSV during a bolus injection of an intravascular tracer in the ear of a piglet resulted in spectral videos of the microvasculature. Analysis of the multispectral videos generated contrast measurements representative of arterial pulsation, the distribution of microvascular transit times, as well as a separation of the venous and arterial signals arising from within the tissue. Therefore, nMSV is capable of acquiring serial multispectral images relevant to tissue hemodynamics, which may have application to the detection and identification of skin cancer.

  6. Changes in thymidylate synthase mRNA in blood leukocytes from patients with colorectal cancer after bolus administration of 5-fluorouracil

    DEFF Research Database (Denmark)

    Ehrnrooth, E; Sørensen, B; Poulsen, J H

    2000-01-01

    5-fluorouracil (5-FU) is considered the standard antineoplastic drug of choice for metastatic colorectal cancer. It has been suggested that 5-FU administered as bolus infusion is cytotoxic mainly through an RNA damaging effect. We investigated the effect of i.v. bolus 5-FU 500-600 mg/m2 on the 5-FU...

  7. The reliability and validity of passive leg raise and fluid bolus to assess fluid responsiveness in spontaneously breathing emergency department patients

    DEFF Research Database (Denmark)

    Duus, Nicolaj; Shogilev, Daniel J; Skibsted, Simon

    2015-01-01

    PURPOSE: We investigated the reproducibility of passive leg raise (PLR) and fluid bolus (BOLUS) using the Non-Invasive Cardiac Output Monitor (NICOM; Cheetah Medical, Tel Aviv, Israel) for assessment of fluid responsiveness (FR) in spontaneously breathing emergency department (ED) patients. METHODS...

  8. Clinical implementation of 3D printing in the construction of patient specific bolus for electron beam radiotherapy for non-melanoma skin cancer

    NARCIS (Netherlands)

    Canters, R.A.M.; Lips, I.M.; Wendling, M.; Kusters, M.; Zeeland, M. van; Gerritsen, R.M.; Poortmans, P.; Verhoef, C.G.

    2016-01-01

    BACKGROUND AND PURPOSE: Creating an individualized tissue equivalent material build-up (i.e. bolus) for electron beam radiation therapy is complex and highly labour-intensive. We implemented a new clinical workflow in which 3D printing technology is used to create the bolus. MATERIAL AND METHODS: A

  9. Clinical implementation of 3D printing in the construction of patient specific bolus for electron beam radiotherapy for non-melanoma skin cancer

    NARCIS (Netherlands)

    Canters, R.A.M.; Lips, I.M.; Wendling, M.; Kusters, M.; Zeeland, M. van; Gerritsen, R.M.; Poortmans, P.; Verhoef, C.G.

    2016-01-01

    BACKGROUND AND PURPOSE: Creating an individualized tissue equivalent material build-up (i.e. bolus) for electron beam radiation therapy is complex and highly labour-intensive. We implemented a new clinical workflow in which 3D printing technology is used to create the bolus. MATERIAL AND METHODS: A

  10. Measurements of the contact force from myenteric contractions on a solid bolus.

    Science.gov (United States)

    Terry, Benjamin S; Schoen, Jonathan A; Rentschler, Mark E

    2013-03-01

    The development of robotic capsule endoscopes (RCEs) is one avenue presently investigated by multiple research groups to minimize invasiveness and enhance outcomes of enteroscopic procedures. Understanding the biomechanical response of the small bowel to RCEs is needed for design optimization of these devices. In previous work, the authors developed, characterized, and tested the migrating motor complex force sensor (MFS), a novel sensor for quantifying the contact forces per unit of axial length exerted by the myenteron on a solid bolus. This work is a continuation, in which the MFS is used to quantify the contractile strength in the small intestine proximal, middle, and distal regions of five live porcine models. The MFSs are surgically implanted in a generally anesthetized animal, and force data from 5 min of dwell time are analyzed. The mean myenteric contact force from all porcine models and locations within the bowel is 1.9 ± 1.0 N cm(-1). Examining the results based on the small bowel region shows a statistically significant strengthening trend in the contractile force from proximal to middle to distal with mean forces of 1.2 ± 0.5, 1.9 ± 0.9, and 2.3 ± 1.0 N cm(-1), respectively (mean ± one standard deviation). Quantification of the contact force against a solid bolus provides developers of RCEs with a valuable, experimentally derived parameter of the intraluminal environment.

  11. 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.

  12. 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.

  13. 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.

  14. Effect of temperature and concentration on thermal conductivity and viscosity of ferrofluid loaded with carbon nanotubes

    Science.gov (United States)

    Shahsavar, A.; Saghafian, M.; Salimpour, M. R.; Shafii, M. B.

    2016-10-01

    The aim of this paper is to investigate the thermal conductivity and viscosity of a hybrid nanofluid containing tetramethylammonium hydroxide (TMAH) coated Fe3O4 nanoparticles and gum arabic (GA) coated carbon nanotubes (CNTs), experimentally. The magnetic nanoparticles and CNTs are physically attached as the result of interaction between the TMAH and GA molecules. The morphology and structure of the samples are characterized with X-ray diffraction (XRD) and transmission electron microscopy (TEM). The experiments are carried out in the magnetic nanoparticles volume concentration range of 0.1-0.9 %, CNT volume concentration range of 0.05-1.35 % and the temperature range of 25-55 °C. The viscosity of the hybrid nanofluid increases with the increase of volume concentration, while it decreases with the increase of temperature. Besides, results show that hybrid nanofluid behaves as a shear thinning fluid. Furthermore, it is observed that the thermal conductivity of the hybrid nanofluid enhances with temperature and volume concentration.

  15. 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.

  16. 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).

  17. 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.

  18. 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,...

  19. Non-Newtonian viscosity in magnetized plasma

    CERN Document Server

    Johnson, Robert W

    2007-01-01

    The particle and momentum balance equations can be solved on concentric circular flux surfaces to determine the effective viscous drag present in a magnetized tokamak plasma in the low aspect ratio limit. An analysis is developed utilizing the first-order Fourier expansion of the poloidal variation of quantities on the flux surface akin to that by Stacey and Sigmar [Phys. Fluids, 28, 9 (1985)]. Expressions to determine the poloidal variations of density, poloidal velocity, toroidal velocity, radial electric field, poloidal electric field, and other radial profiles are presented in a multi-species setting. Using as input experimental data for the flux surface averaged profiles of density, temperature, toroidal current, toroidal momentum injection, and the poloidal and toroidal rotations of at least one species of ion, one may solve the equations numerically for the remaining profiles. The resultant effective viscosities are compared to those predicted by Stacey and Sigmar and Shaing, et al., [Nuclear Fusion, 2...

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Vapor pressure, density, viscosity and refractive index of dimethyl sulfoxide + 1,4-dimethylbenzene system

    Directory of Open Access Journals (Sweden)

    OANA CIOCIRLAN

    2008-01-01

    Full Text Available This paper reports the experimental results of isothermal vapor–liquid equilibrium data between 303.15 and 333.15 K, and densities, viscosities, refractive indices from 298.15 to 323.15 K of the dimethyl sulfoxide + 1,4-dimethylbenzene system over the entire range of mixture composition. The obtained PTX data were correlated by the Wilson and NRTL models and estimated by the UNIFAC model. The excess Gibbs energy and activity coefficients were calculated and compared with others excess properties. Excess molar volumes, viscosity deviations and deviations in refractivity were calculated from the experimental data; all the computed quantities were fitted to the Redlich–Kister equation. The resulting excess functions were interpreted in terms of structure and interactions.

  6. Mantle Dynamics in Super-Earths: Post-Perovskite Rheology and Self-Regulation of Viscosity

    CERN Document Server

    Tackley, Paul J; Brodholt, John P; Dobson, David P; Valencia, Diana

    2012-01-01

    Simple scalings suggest that super-Earths are more likely than an equivalent Earth-sized planet to be undergoing plate tectonics. Generally, viscosity and thermal conductivity increase with pressure while thermal expansivity decreases, resulting in lower convective vigor in the deep mantle. According to conventional thinking, this might result in no convection in a super-Earth's deep mantle. Here we evaluate this. First, we here extend the density functional theory (DFT) calculations of post-perovskite activation enthalpy of to a pressure of 1 TPa. The activation volume for diffusion creep becomes very low at very high pressure, but nevertheless for the largest super-Earths the viscosity along an adiabat may approach 1030 Pa s in the deep mantle. Second, we use these calculated values in numerical simulations of mantle convection and lithosphere dynamics of planets with up to ten Earth masses. The models assume a compressible mantle including depth-dependence of material properties and plastic yielding induce...

  7. 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

  8. 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.

  9. 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.

  10. Assessment of an oxfendazole pulsed release bolus for control of parasitic gastroenteritis in calves in a rotational grazing system.

    Science.gov (United States)

    Mitchell, G B

    1987-10-17

    A group of 71 Friesian bullocks, aged six to nine months, vaccinated against lungworm, were randomly allocated on a liveweight basis to two groups of 40 and 31 animals. At turn-out each calf in the group of 40 calves was dosed orally with a pulsed release bolus designed to deliver five doses of oxfendazole at regular intervals during a period of up to 130 days, the first dose being released about 21 days after administration. The group treated with the bolus grazed 2.4 ha and the control group grazed 3.6 ha of permanent pasture for six weeks before having additional access to similar areas of silage aftermath. The control group was treated 99 days after turn-out and when they were housed with fenbendazole (7.5 mg/kg). Faecal worm egg counts, plasma pepsinogen activities, pasture larval counts and liveweights were recorded fortnightly. Significant reductions in worm egg counts and plasma pepsinogen activities were recorded in the calves dosed with the pulsed release bolus together with significant improvements in the liveweight of younger calves compared with control animals. Pasture larval counts were lower in the fields grazed by animals treated with the bolus.

  11. Changes in fat concentration of human milk during delivery by intermittent bolus and continuous mechanical pump infusion.

    Science.gov (United States)

    Greer, F R; McCormick, A; Loker, J

    1984-11-01

    The changes in fat concentration and cumulative fat losses that occur during the delivery of human milk using two different continuous infusion systems were compared with the changes in fat concentration during simulated intermittent gavage or bolus feedings. With both mechanical pumps the largest cumulative fat losses and the greatest decreases in fat concentrations occurred at the slowest infusion rates. State of homogenization of the milk generally made little difference in the changes in fat concentration using the syringe pump, whereas homogenizing the milk increased the fat concentration significantly with the roller pump. With the syringe pump the positioning of the syringe tip (horizontal or vertical) made no difference in fat concentration at an infusion rate of 1 ml/hr, whereas at 4 and 7 ml/hr the fat concentration was increased significantly by keeping the syringe tip vertical. With either mechanical pump a large fat bolus was delivered during the eighth and final hour of infusion if the milk remaining in the tubing was recovered by using air infusion at the same infusion rate. Intermittent bolus delivery of human milk resulted in no significant loss of human milk fat, no changes in fat concentration, and no terminal delivery of a large fat load. Thus intermittent bolus feedings are preferred over continuous mechanical pump infusion systems for the delivery of human milk to low-birth-weight infants.

  12. Taste enhancement in food gels: Effect of fracture properties on oral breakdown, bolus formation and sweetness intensity

    NARCIS (Netherlands)

    Mosca, A.C.; Velde, van de F.; Bult, J.H.F.; Boekel, van M.A.J.S.; Stieger, M.A.

    2015-01-01

    This study investigates the effects of fracture strain and fracture stress on oral breakdown, bolus formation and sweetness intensity of semi-solid food gels containing sucrose heterogeneously distributed in layers. The sweetness intensity of gels was mainly affected by the total surface area of gel

  13. Taste enhancement in food gels: Effect of fracture properties on oral breakdown, bolus formation and sweetness intensity

    NARCIS (Netherlands)

    Mosca, A.C.; Velde, van de F.; Bult, J.H.F.; Boekel, van M.A.J.S.; Stieger, M.A.

    2015-01-01

    This study investigates the effects of fracture strain and fracture stress on oral breakdown, bolus formation and sweetness intensity of semi-solid food gels containing sucrose heterogeneously distributed in layers. The sweetness intensity of gels was mainly affected by the total surface area of gel

  14. Use of 3D printers to create a patient-specific 3D bolus for external beam therapy.

    Science.gov (United States)

    Burleson, Sarah; Baker, Jamie; Hsia, An Ting; Xu, Zhigang

    2015-05-08

    The purpose of this paper is to demonstrate that an inexpensive 3D printer can be used to manufacture patient-specific bolus for external beam therapy, and to show we can accurately model this printed bolus in our treatment planning system for accurate treatment delivery. Percent depth-dose measurements and tissue maximum ratios were used to determine the characteristics of the printing materials, acrylonitrile butadiene styrene and polylactic acid, as bolus material with physical density of 1.04 and 1.2 g/cm3, and electron density of 3.38 × 10²³ electrons/cm3 and 3.80 × 10²³ electrons/ cm3, respectively. Dose plane comparisons using Gafchromic EBT2 film and the RANDO phantom were used to verify accurate treatment planning. We accurately modeled a printing material in Eclipse treatment planning system, assigning it a Hounsfield unit of 260. We were also able to verify accurate treatment planning using gamma analysis for dose plane comparisons. With gamma criteria of 5% dose difference and 2 mm DTA, we were able to have 86.5% points passing, and with gamma criteria of 5% dose difference and 3 mm DTA, we were able to have 95% points passing. We were able to create a patient-specific bolus using an inexpensive 3D printer and model it in our treatment planning system for accurate treatment delivery.

  15. Low-dose esmolol bolus reduces seizure duration during electroconvulsive therapy: a double-blind, placebo-controlled study

    NARCIS (Netherlands)

    W.W. van den Broek (Walter); A.F. Leentjens; A. Kusuma (Ari); J.A. Bruijn (Jan); P.G.H. Mulder (Paul)

    1999-01-01

    textabstractWe have measured the effect of a bolus dose of esmolol 80 mg i.v. on heart rate, and systolic (SAP), diastolic (DAP) and mean (MAP) arterial pressures during electroconvulsive therapy (ECT). We also assessed seizure duration using both the cuff method and tw

  16. Evaluation of polymers of different degrees viscosities as additives for drilling fluids for oil well; Avaliacao de polimeros de diferentes graus de viscosidades como aditivos para fluidos de perfuracao de pocos de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Farias, K.V.; Amorim, L.V.; Silva, A.V. [Universidade Federal de Campina Grande (DEMa/UFCG), PB (Brazil); Lira, H.L. [Universidade Federal de Campina Grande (CCT/UFCG), PB (Brazil). Centro de Ciencias e Tecnologia. Unidade Academica de Engenharia de Materiais], e-mail: kassiefarias@gmail.com

    2008-07-01

    The objective of this work is to study the polymers influence of different degrees of viscosity, used as viscositying and filtered reducer additives, in the rheological, filtration and lubricity properties of drilling fluids for oil wells. Were determined the rheological behavior, the apparent and plastic viscosities, the yield limit and gel force, the filtered volume and the lubricity coefficient in accordance with API standard. The fluids showed pseudoplastic behavior with properties close to the standard fluid; the increase of viscositying and filtered reducer concentrations lead to the increase of rheological properties and the filtered reducer values, from the concentration of 3,5g/350mL of water it acted as viscositying, increasing the values of apparent and plastic viscosities, yield limit and gel force, being 3,0g/350mL of water the adequate concentration of this additive, promoting better results of rheological and filtration properties. (author)

  17. SU-E-T-176: Clinical Experience of Brass Mesh Bolus: Patient-Specific Parameters as Predictors of Measured Dosimetric Effect

    Energy Technology Data Exchange (ETDEWEB)

    Yock, A; Manger, R; Einck, J; Yashar, C; Sanghvi, P; Hattangadi-Gluth, J; Cervino, L [University of California - San Diego, La Jolla, CA (United States)

    2015-06-15

    Purpose: Increasingly, brass mesh bolus is used to insure dosimetric coverage of the skin for patients treated post-mastectomy for breast cancer. Contribution of photoelectrons from interactions between the bolus and the primary beam increases dose superficially without affecting dose at greater depths. We present our experience using brass mesh bolus – including patients for whom the bolus was dosimetrically inadequate – along with analysis of relevant patient-specific parameters. Methods: Optically-stimulated luminescent dosimeters (OSLDs) were used to determine the effect of the bolus for 15 patients. They were positioned beneath the bolus within the tangent fields at three positions: 1.5–3cm inside the medial and lateral field edges, and midway between the two. All OSLDs were midfield in the cranial-caudal direction. The measurements were compared with patient-specific parameters including separation, chest wall/breast tissue thickness, beam angle incidence, and planned surface dose. Results: The average OSLD measurement at the medial field edge, midfield, and lateral field edge position was 86.8%, 101.8%, and 92.8% of the prescription dose, respectively. A measurement for one patient was low enough (77.0%) to warrant a switch to an alternative type of bolus. Anatomic parameters were analyzed to investigate the low dose in this case, not observed in the planning system. The patient was observed to have a thin chest wall and very oblique beam angles. A second patient was also switched to an alternative type of bolus due to her being high risk and treated with an electron patch that extended onto the breast. Conclusion: Brass mesh bolus increases dose superficially while leaving dose at greater depths unaffected. However, our results suggest that this effect may be insufficient in patients with a thin chest wall or very oblique beam angles. More data and analysis is necessary to proactively identify patients for whom brass mesh bolus is effective.

  18. Densities, viscosities, and ultrasonic velocity studies of binary mixtures of trichloromethane with methanol, ethanol, propan-1-ol, and butan-1-ol at T = (298.15 and 308.15) K

    Energy Technology Data Exchange (ETDEWEB)

    Kadam, Ujjan B. [P.G. Department of Physical Chemistry, M.S.G. College, Loknete Vyankatrao Hiray Marg, Malegaon Camp, Maharashtra 423 105 (India); Hiray, Apoorva P. [P.G. Department of Physical Chemistry, M.S.G. College, Loknete Vyankatrao Hiray Marg, Malegaon Camp, Maharashtra 423 105 (India); Sawant, Arun B. [Arts, Science and Commerce College, Nampur 423 204 (India); Hasan, Mehdi [P.G. Department of Physical Chemistry, M.S.G. College, Loknete Vyankatrao Hiray Marg, Malegaon Camp, Maharashtra 423 105 (India)]. E-mail: mihasan@rediffmail.com

    2006-12-15

    Densities, viscosities, and ultrasonic velocities of binary mixtures of trichloromethane with methanol, ethanol, propan-1-ol, and butan-1-ol have been measured over the entire range of composition, at (298.15 and 308.15) K and at atmospheric pressure. From the experimental values of density, viscosity, and ultrasonic velocity, the excess molar volumes (V {sup E}), deviations in viscosity ({delta}{eta}), and deviations in isentropic compressibility ({delta}{kappa} {sub s}) have been calculated. The excess molar volumes, deviations in viscosity and deviations in isentropic compressibility have been fitted to the Redlich-Kister polynomial equation. The Jouyban-Acree model is used to correlate the experimental values of density, viscosity, and ultrasonic velocity.

  19. The optimal exhaled concentration of sevoflurane for intubation without neuromuscular blockade using clinical bolus doses of remifentanil

    Science.gov (United States)

    Goo, Eui-Kyoung; Lee, Jong Seok; Koh, Jae Chul

    2017-01-01

    Abstract Background: The aim of this study was to investigate the optimal exhaled sevoflurane concentration that produces adequate endotracheal intubation conditions when sevoflurane is combined with the different bolus doses of remifentanil used in clinical practice. Methods: The patients were randomized to 3 groups (groups 1.0, 1.5, and 2.0), receiving remifentanil bolus doses of 1.0, 1.5, and 2.0 μg/kg, respectively. For each group, the concentration of sevoflurane used for each consecutive patient was increased or decreased using the “up-and-down” method based on the success or failure to achieve adequate conditions for intubation in the previous patient. The remifentanil bolus dose was administered 90 s before intubation and after the target sevoflurane concentration was achieved. Results: In groups 1.0, 1.5, and 2.0, the effective concentration in 50% (EC50) of the sevoflurane concentration required to perform successful intubation was 3.0, 2.0, and 1.29 vol% and the effective concentration in 95% was 3.45, 2.91, and 1.89 vol%, respectively. When sevoflurane was administered for the induction, the increase in heart rate (HR) of group 1.0 was the highest among the groups. The highest number of adverse events occurred in group 2.0, including vocal cord rigidity, hypotension, and bradycardia. Discussion: The EC50 of the sevoflurane concentration was 3.0, 2.0, and 1.29 vol% when it was combined with a bolus dose of remifentanil of 1.0, 1.5, and 2.0 μg/kg, respectively. Of the 3 different bolus doses of remifentanil, the dose of 1.5 μg/kg was least associated with changes in the HR/mean blood pressure during intubation without increasing adverse effects. PMID:28248887

  20. 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.

  1. Effects of temperature and particles concentration on the dynamic viscosity of MgO-MWCNT/ethylene glycol hybrid nanofluid: Experimental study

    Science.gov (United States)

    Soltani, Omid; Akbari, Mohammad

    2016-10-01

    In this paper, the effects of temperature and particles concentration on the dynamic viscosity of MgO-MWCNT/ethylene glycol hybrid nanofluid is examined. The experiments carried out in the solid volume fraction range of 0 to 1.0% under the temperature ranging from 30 °C to 60 °C. The results showed that the hybrid nanofluid behaves as a Newtonian fluid for all solid volume fractions and temperatures considered. The measurements also indicated that the dynamic viscosity increases with increasing the solid volume fraction and decreases with the temperature rising. The relative viscosity revealed that when the solid volume fraction enhances from 0.1 to 1%, the dynamic viscosity increases up to 168%. Finally, using experimental data, in order to predict the dynamic viscosity of MgO-MWCNT/ethylene glycol hybrid nanofluids, a new correlation has been suggested. The comparisons between the correlation outputs and experimental results showed that the suggested correlation has an acceptable accuracy.

  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. Suitability of electronic mini-boluses for the early identification of goat kids and effects on growth performance and development of the reticulorumen.

    Science.gov (United States)

    Castro, N; Martín, D; Castro-Alonso, A; Argüello, A; Capote, J; Caja, G

    2010-10-01

    A total of 60 twin-goat kids (30 male and 30 female) of the Canary Island Majorera dairy breed were used in 2 experiments to evaluate 2 types of electronic identification mini-boluses and their effects on rearing performances and reticulorumen development. Electronic identification mini-boluses were cylindrical and made of ceramic materials (B1, 9.0 g and 38.5 × 9.5 mm; B2, 16.3 g and 42.2 × 12.2 mm), contained a 32-mm half-duplex passive transponder, and were administered to kids at different BW. In Exp. 1, treatments were 1) control, without bolus (n = 15) and 2) identified with B1 at 4.8 kg of BW (n = 15). In Exp. 2, treatments were 1) control, without bolus (n = 15) and 2) identified with B2 at 5.6 kg of BW (n = 15). Kids were penned separately, according to mini-bolus treatments, fed a milk replacer daily, and slaughtered at 10 kg of BW. Milk replacer intake was recorded individually twice weekly and boluses read weekly until slaughter. The full and empty stomach complex was measured immediately after slaughter, and mini-bolus location was recorded. Samples of the reticulum and rumen wall were taken to measure the number and length of the papillae and crest. Despite the light BW of kids at time of mini-bolus treatment, no negative effects (P > 0.05) of B1 and B2 mini-boluses were observed on milk intake, growth rate, or G:F in either experiment. No kid mortality or mini-bolus losses were observed during either experiment. All mini-boluses were retained until slaughter, and all were found in the rumen upon dissection, except one B2, which was found in the reticulum. Mini-bolus treatment did not affect (P > 0.05) the weight of full and empty reticulorumen or the number of papillae and crest size of the reticulum epithelium. Moreover, the B1-treated kids showed a greater number of papillae in the rumen wall than the control kids (22.4 +/- 1.0 vs. 18.9 +/- 0.9 papillae/cm, respectively; P kids from early ages (wk 2 to 5 of age and 5 to 6 kg of BW) and did not

  4. Trophallaxis in the honeybee, Apis mellifera : the interaction between viscosity and sucrose concentration of the transferred solution.

    Science.gov (United States)

    Tezze; Farina

    1999-06-01

    Trophallaxis by honeybee foragers was studied under the experimental conditions of an arena. The behaviour of pairs of bees, one (donor) fed with 50-&mgr;l sucrose solutions and another unfed recipient, was analysed as a function of the sucrose concentration, the concentration at constant viscosity (kept constant by adding tylose, an inert polysaccharide), and of the viscosity of a 30% sucrose solution. By increasing the concentration of solutions, the rate at which the solution was transferred to recipient bees (transfer rate of solution, in &mgr;l/s) increased up to a maximum value for 30% sucrose solution, and decreased beyond this concentration (concentration experiment). At constant viscosity, no modulation was observed for the lower sugar concentration range (10-30%), while the transfer rate of solution clearly increased beyond 30% (concentration experiment at constant viscosity). For the 30% sucrose solution, the transfer rate decreased with increasing viscosity (viscosity experiment). If only the sucrose compound is comparatively analysed, the transfer rate of sucrose (in mg/s) increased similarly in the first two experiments. These results give behavioural evidence suggesting that donor bees are capable of modulating the trophallactic food transfer as related to the sucrose concentrations carried into their crops within a considerable wide range, but viscosity prevents it. It also suggests that trophallactic transfer rate does not depend on abdominal volume, for even when all donor bees attained similar loads (50 &mgr;l), transfer rate of solution increased along with the offered sucrose concentration. Results are discussed in relation to the information exchange performed in the foraging context displayed by foragers. Copyright 1999 The Association for the Study of Animal Behaviour.

  5. 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/

  6. 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.

  7. 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...

  8. 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...

  9. 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.

  10. 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....

  11. Viscosity of liquids theory, estimation, experiment, and data

    CERN Document Server

    Viswanath, Dabir S; Prasad, Dasika HL; Dutt, Nidamarty VK; Rani, Kalipatnapu Y

    2007-01-01

    Single comprehensive book on viscosity of liquids, as opposed to most of the books in this area which are data books, i.e., a compilation of viscosity data from the literature, where the information is scattered and the description and analysis of the experimental methods and governing theory are not readily available in a single place.

  12. 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...

  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. 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.

  15. 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...

  16. 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.

  17. 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.

  18. Viscosity Reduction in Liquid Suspensions by Electric or Magnetic Fields

    Science.gov (United States)

    Tao, R.; Xu, X.

    Reducing the viscosity of liquid suspensions is of great importance in science and engineering. We present a theory and experiments that a suitable electric or magnetic field pulse can effectively reduce the viscosity for several hours with no appreciable change of temperature. Positive experimental results with magnetorheological fluids and crude oil suggest a broad range of practical applications.

  19. 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.

  20. 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/

  1. 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...

  2. 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...

  3. 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.

  4. 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.

  5. Modulation of Upper Esophageal Sphincter (UES) Relaxation and Opening During Volume Swallowing.

    Science.gov (United States)

    Cock, Charles; Jones, Corinne A; Hammer, Michael J; Omari, Taher I; McCulloch, Timothy M

    2016-08-17

    UES opening occurs following cricopharyngeus deactivation and submental muscle contraction causing hyolaryngeal elevation and UES distraction. During impedance manometry, the inverse of impedance (admittance) can be used to measure bolus presence and infer UES opening. We hypothesized that the temporal relationship between UES relaxation, opening and hyolaryngeal elevation would change with increasing bolus volume. Simultaneous intramuscular cricopharyngeal (CP) electromyography (EMG), surface submental EMG (SM-EMG), and high-resolution impedance manometry were recorded in eight (aged 27 ± 7 years, 5 M) healthy volunteers, while swallowing 0.9 % saline boluses of 2, 5, 10, and 20 ml. Data were exported and analyzed via Matlab. Statistical analysis comprised repeated measures one-way ANOVA and Pearson correlation. A P value of EMG activity occurs relatively later (P modulation of cricopharyngeal and submental muscle activity. Intrabolus pressures, transmitted from the tongue base and pharynx, play a progressively more important role in sphincter opening with increasing volume. The findings may explain why some healthy elderly and patients with oropharyngeal dysphagia have difficulty swallowing larger while tolerating smaller bolus volumes.

  6. Density, viscosity, surface tension, and spectroscopic properties for binary system of 1,2-ethanediamine + diethylene glycol

    Energy Technology Data Exchange (ETDEWEB)

    Li, Lihua; Zhang, Jianbin, E-mail: tadzhang@pku.edu.cn; Li, Qiang; Guo, Bo; Zhao, Tianxiang; Sha, Feng

    2014-08-20

    Graphical abstract: Excess property of the binary system 1,2-ethanediamine (EDA) + diethylene glycol (DEG). - Highlights: • Densities and viscosities of EDA + DEG at 298.15–318.150 K were listed. • Thermodynamics data of EDA + DEG at 298.15–318.15 K were calculated. • Surface tension of EDA + DEG at 298.15 K was measured. • Intermolecular interaction of EDA with DEG was discussed. - Abstract: This paper reports density and viscosity data at T = 298.15, 303.15, 308.15, 313.15, and 318.15 K and surface tension data at 298.15 K for the binary system 1,2-ethanediamine (EDA) + diethylene glycol (DEG) as a function of composition under atmospheric pressure. From the experimental density and viscosity data, the excess molar volume and viscosity deviation were calculated, and the results were fitted to a Redlich–Kister equation to obtain the coefficients and to estimate the standard deviations between the experimental and calculated quantities. Based on the kinematic viscosity data, enthalpy of activation for viscous flow, entropy of activation for the viscous flow, and Gibbs energies of activation of viscous flow were calculated. In addition, based on Fourier transform infrared spectra, UV–vis spectra, and electrical conductivity for the system EDA + DEG with various concentrations, intermolecular interaction of EDA with DEG was discussed.

  7. Temperature dependence of density, thermal expansion coefficient and shear viscosity of supercooled glycerol as a reflection of its structure.

    Science.gov (United States)

    Blazhnov, Ivan V; Malomuzh, Nikolay P; Lishchuk, Sergey V

    2004-10-01

    The relationship of the microstructure of supercooled, highly viscous glycerol to the temperature dependence of its density, thermal expansion coefficient, and shear viscosity are discussed. The character of this temperature dependence at the transition from low viscosity state to the solid amorphous state (solidified state without nuclei) is described with help of function psi, which can be interpreted as the effective number of degrees of freedom responsible for the change of viscosity of glycerol over a broad range; these degrees of freedom are those related to the alpha-relaxation process. It is shown that the change in effective activation energy of the viscosity is completely determined by the parameter psi. The change in the shear viscosity of glycerol due to the influence of the solid-phase nuclei is considered. It is shown that the introduction of the parameter phi, equal to the specific volume occupied by the nuclei of the solid phase, together with psi provides a natural explanation of the temperature dependence of density and thermal expansion coefficients of glycerol in its liquid, solid amorphous, glassy, and crystal states. The peculiarities of the temperature dependence of phi(T) and psi(T) for glycerol and o-terphenyl are compared.

  8. 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...

  9. Integrated Solvent Design for CO2 Capture and Viscosity Tuning

    Energy Technology Data Exchange (ETDEWEB)

    Cantu Cantu, David; Malhotra, Deepika; Koech, Phillip K.; Heldebrant, David J.; Zheng, Feng; Freeman, Charles J.; Rousseau, Roger J.; Glezakou, Vassiliki-Alexandra

    2017-07-03

    We present novel design strategies for reduced viscosity single-component, water-lean CO2 capture organic solvent systems. Through molecular simulation, we identify the main molecular-level descriptor that influences bulk solvent viscosity. Upon loading, a zwitterionic structure forms with a small activation energy of ca 16 kJ/mol and a small stabilization of ca 6 kJ/mol. Viscosity increases exponentially with CO2 loading due to hydrogen-bonding between neighboring Zwitterions. We find that molecular structures that promote internal hydrogen bonding (within the same molecule) and suppress interactions with neighboring molecules have low viscosities. In addition, tuning the acid/base properties leads to a shift of the equilibrium toward a non-charged (acid) form that further reduces the viscosity. Based on the above structural criteria, a reduced order model is also presented that allows for the quick screening of large compound libraries and down selection of promising candidates for synthesis and testing.

  10. 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.

  11. 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.

  12. 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.)

  13. 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.

  14. 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.

  15. The use of a radiotelemetric ruminal bolus to detect body temperature changes in lactating dairy cattle.

    Science.gov (United States)

    Alzahal, O; Alzahal, H; Steele, M A; Van Schaik, M; Kyriazakis, I; Duffield, T F; McBride, B W

    2011-07-01

    The objective of this study was to validate the efficacy of a radiotelemetric bolus (RTB) to detect changes in ruminal temperature resulting from (1) systemic illnesses that are associated with febrile responses and (2) subacute ruminal acidosis (SARA). Eight rumen-fistulated, lactating Holstein cows (586±37 kg of body weight, 106±18 d in milk) were used in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement. Each period consisted of 21 d. The factors were 2 diets, a moderate forage:concentrate [MFC; 52:48; % of dry matter (DM)] or a high forage:concentrate (HFC; 65:35, % of DM) total mixed ration, and a challenge with a single intramammary injection of lipopolysaccharide (LPS; 100 μg derived from Escherichia coli 0111:B4) or no LPS (sterile saline). Thus, the 4 resulting treatments were (1) MFC with LPS challenge, (2) MFC with saline, (3) HFC with LPS challenge, and (4) HFC with saline. Cows were fed at 0800 and 1400 h daily. Cows received the intramammary injections at 0900 h of d 21. Ruminal pH and ruminal temperature were also measured on d 21 every minute via an indwelling logging system that resided in the ventral sac of the rumen and via a radiotelemetric bolus that resided in the reticulum. Vaginal temperature was also recorded every minute via temperature loggers. Prior to LPS injection, the duration of rumen pH below 5.6 (indicative of SARA) was higher in cows receiving MFC than cows receiving HFC (148±24 and 62±24 min/d, respectively). The temperature measured at the same time via RTB was higher for MFC than HFC cows (167±21 vs. 104 vs. 21 min/d above 38.8°C, respectively). The following day, cows challenged with LPS showed signs of mastitis within the injected quarters, depressed DM intake, decreased milk yield, and a peak vaginal temperature of 41.3±0.1°C 5.5h after the LPS injection. The RTB system successfully detected a fever response parallel to that measured by the vaginal loggers but temperature peak detected by

  16. 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...

  17. Protein viscosity, mineral fraction and staggered architecture cooperatively enable the fastest stress wave decay in load-bearing biological materials.

    Science.gov (United States)

    Qwamizadeh, Mahan; Zhang, Zuoqi; Zhou, Kun; Zhang, Yong Wei

    2016-07-01

    One of the key functions of load-bearing biological materials, such as bone, dentin and sea shell, is to protect their inside fragile organs by effectively damping dynamic impact. How those materials achieve this remarkable function remains largely unknown. Using systematic finite element analyses, we study the stress wave propagation and attenuation in cortical bone at the nanoscale as a model material to examine the effects of protein viscosity, mineral fraction and staggered architecture on the elastic wave decay. It is found that the staggered arrangement, protein viscosity and mineral fraction work cooperatively to effectively attenuate the stress wave. For a typical mineral volume fraction and protein viscosity, an optimal staggered nanostructure with specific feature sizes and layouts is able to give rise to the fastest stress wave decay, and the optimal aspect ratio and thickness of mineral platelets are in excellent agreement with experimental measurements. In contrary, as the mineral volume fraction or the protein viscosity goes much higher, the structural arrangement is seen having trivial effect on the stress wave decay, suggesting that the damping properties of the composites go into the structure-insensitive regime from the structure-sensitive regime. These findings not only significantly add to our understanding of the structure-function relationship of load-bearing biological materials, and but also provide useful guidelines for the design of bio-inspired materials with superior resistance to impact loading.

  18. 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…

  19. Growth hormone and prolactin responses to bolus and sustained infusions of GRH-1-40-OH in man.

    Science.gov (United States)

    Goldman, J A; Molitch, M E; Thorner, M O; Vale, W; Rivier, J; Reichlin, S

    1987-08-01

    To determine whether GRH stimulates PRL secretion we studied the effects of iv bolus injections and prolonged infusions of GRH 1-40-OH on PRL and GH serum levels in normal volunteers. Eight patients with acromegaly, two of whom had elevated basal levels of PRL, were also tested with single bolus injections. Six normal subjects given 3.3 micrograms/kg bolus injections of GRH showed a mean increment of GH of 22.0 +/- 1.7 ng/ml (mean +/- SE). A small rise in PRL was noted in 5 of the 6 subjects (mean peak level of 6.4 +/- 1.9 ng/ml vs basal level of 3.3 +/- 0.4 ng/ml, p less than 0.05). During the continuous intusion of GRH (10 ng/kg/min), GH levels rose gradually from a mean baseline of 1.1 +/- 0.1 ng/ml to a mean peak of 30.0 +/- 7.2 ng/ml at about 2 h and then slowly declined to a nadir of 4.2 +/- 0.4 ng/ml at 330 min. PRL levels did not rise significantly during the infusion. To determine whether the decline in GH levels in the face of continued infusion was due to loss of GH responsiveness, a 3.3 micrograms/kg bolus of GRH was given during the nadir at 330 min; this GH increment was significantly less than that obtained by the GRH bolus injection without the infusion (12.9 +/- 3.5 ng/ml vs 22.0 +/- 1.7 ng/ml, p less than 0.05). The PRL response to the GRH bolus was the same during the infusion of GRH as before. In each of 8 acromegalic patients (including two who had initially elevated basal PRL levels) GRH led to an increase in both GH and PRL levels. PRL and GH levels spontaneously fluctuated in parallel in 4 acromegalic cases studied with repeated samples over 6 h during placebo administration. These experiments show that GRH has significant, though weak, PRF effect in normals and that it is more potent PRF in acromegalic patients. Furthermore, the effects on GH and PRL of a sustained infusion of GRH for 5 1/2 h are both qualitatively and quantitatively different. These results suggest that the GRH effect is exerted either on different pituitary receptors for

  20. WE-F-16A-05: Use of 3D-Printers to Create a Tissue Equivalent 3D-Bolus for External Beam Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Burleson, S; Baker, J; Hsia, A; Xu, Z [Stony Brook Medicine, Stony Brook, NY (United States)

    2014-06-15

    Purpose: The purpose of this project is to demonstrate that a non-expensive 3D-printer can be used to manufacture a 3D-bolus for external beam therapy. The printed bolus then can be modeled in our treatment planning system to ensure accurate dose delivery to the patient. Methods: We developed a simple method to manufacture a patient-specific custom 3Dbolus. The bolus is designed using Eclipse Treatment Planning System, contoured onto the patients CT images. The bolus file is exported from Eclipse to 3D-printer software, and then printed using a 3D printer. Various tests were completed to determine the properties of the printing material. Percent depth dose curves in this material were measured with electron and photon beams for comparison to other materials. In order to test the validity of the 3D printed bolus for treatment planning, a custom bolus was printed and tested on the Rando phantom using film for a dose plane comparison. We compared the dose plane measured on the film to the same dose plane exported from our treatment planning system using Film QA software. The gamma-dose distribution tool was used in our film analysis. Results: We compared point measurements throughout the dose plane and were able to achieve greater than 95% passing rate at 3% dose difference and 3 mm distance to agreement, which is our departments acceptable gamma pixel parameters. Conclusion: The printed 3D bolus has proven to be accurately modeled in our treatment planning system, it is more conformal to the patient surface and more durable than other bolus currently used (wax, superflab etc.). It is also more convenient and less costly than comparable bolus from milling machine companies.

  1. Safe and Efficacious Use of Automated Bolus Advisors in Individuals Treated With Multiple Daily Insulin Injection (MDI) Therapy: Lessons Learned From the Automated Bolus Advisor Control and Usability Study (ABACUS).

    Science.gov (United States)

    Parkin, Christopher G; Barnard, Katharine; Hinnen, Deborah A

    2015-03-20

    Numerous studies have shown that use of integrated automated bolus advisors (BAs) provides significant benefits to individuals using insulin pump devices, including improved glycemic control and greater treatment satisfaction. Within the past few years, BA devices have been developed specifically for individuals treated with multiple daily insulin injection (MDI) therapy; however, many clinicians who treat these individuals may be unfamiliar with insulin pump therapy and, thus, BA use. Findings from the Automated Bolus Advisor Control and Usability Study (ABACUS) revealed that BA use can be efficacious and clinically meaningful in MDI therapy, and that most patients are willing and able to use this technology appropriately when adequate clinical support is provided. The purpose of this article is to review key learnings from ABACUS and provide practical advice for initiating BA use and monitoring therapy.

  2. 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

  3. Dosimetry characterization and clinical application of Exa skin: Bolus of high of high density for use with photons; Caracterizacion dosimetrica y aplicacion clinica de Exaskin: bolus de alta densidad para uso con fotones

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz Seidel, M.; Velazquez Miranda, S.

    2013-07-01

    Bolus of high density eXaSkin of density 1.6 g/cm{sub 3} is calculated correctly in the planning systems, is easy to use and generates optimum coupling with the radiation area, at the same time which is easily reproducible in their placement, avoiding the use of electron beams. On the other hand its behavior varies very slightly with the presence of air gaps. (Author)

  4. Starch Modifications to Improve the Paste Stabilities Both in Phase and Viscosity for Warp Sizing

    Institute of Scientific and Technical Information of China (English)

    ZHU Zhi-feng; YU Jie; YU Cui-yun

    2005-01-01

    An attempt has been made to improve the paste stabilities both in viscosity of a hot starch paste and in phase of a starch-polyvinyl alcohol blend paste for warp sizing. The phase stability was evaluated in terms of the initial demixing time, and the volume percentage of polyvinyl alcohol separated. It was found that starch cross-linking is harmful to the phase stability of a starch-polyvinyl alcohol blend paste no matter what a type of polyvinyl alcohol is used,although the cross-linking is an effective technique for stabilizing the viscosity of a hot starch paste. The separation rate and extent all increase with the increase in the cross-linking degree of starch. However, this defect can be eliminated through introducing quaternary ammonium groups into crosslinked starch molecules. Evident effect can be achieved when the degree of substitution is as less as0.021. Generally, increase in the DS reduces the separation rate and extent, and thereby raising the phase stability.Moreover, the effects of both starch content and PVA type on the separation are also considered. Cationization after starch cross-linking shows improved stabilities both in viscosity and phase.

  5. Measurements and modelling of phase behaviour and viscosity of a heavy oil-butane system

    Energy Technology Data Exchange (ETDEWEB)

    Yazdani, A.; Maini, B.B. [Calgary Univ., AB (Canada)

    2007-07-01

    Solvent based recovery processes are environmentally friendly alternatives for thermal techniques. Information on the phase behavior of the heavy oil/solvent system is needed for numerical simulation and feasibility studies of these processes. However, the lack of experimental data for such systems in the literature has been problematic. Solvent/oil mixtures that are evaluated within the context of the vapour extraction (VAPEX) process, require accurate description of the system's pressure, volume, and temperature (PVT) properties. This paper presented the results of a study that designed an experimental set-up and conducted several experiments in order to obtain the required PVT information. The paper presented the results of the PVT experiments conducted with the Frog-Lake heavy oil/butane system that was used in VAPEX experiments reported previously by the authors. The experimental measurements included the solvent fractions in the oil, mixture density and mixture viscosity at different saturation pressures. Using the phase behavior package WINPROP, the PVT results were modeled and an equation of state (EOS) was tuned for simulating the experimental behavior of the system. The viscosity measurements were compared with the predictions of several available correlations. It was concluded that the predicted values of EOS for density and saturation pressure were in agreement with the obtained experimental data and that a mixing type relationship was found to be adequate for describing the viscosity of heavy oil - solvent mixtures. 12 refs., 4 tabs., 10 figs.

  6. A discrete model for the apparent viscosity of polydisperse suspensions including maximum packing fraction

    CERN Document Server

    Dörr, Aaron; Mehdizadeh, Amirfarhang

    2012-01-01

    Based on the notion of a construction process consisting of the stepwise addition of particles to the pure fluid, a discrete model for the apparent viscosity as well as for the maximum packing fraction of polydisperse suspensions of spherical, non-colloidal particles is derived. The model connects the approaches by Bruggeman and Farris and is valid for large size ratios of consecutive particle classes during the construction process. Furthermore, a new general form of the well-known Krieger equation allowing for the choice of a second-order Taylor coefficient for the volume fraction is proposed and then applied as a monodisperse reference equation in the course of polydisperse modeling. By applying the polydisperse viscosity model to two different particle size distributions (Rosin-Rammler and uniform distribution), the influence of polydispersity on the apparent viscosity is examined. The extension of the model to the case of small size ratios as well as to the inclusion of shear rate effects is left for fut...

  7. Effect of dexmedetomidine bolus dose on isoflurane consumption in surgical patients under general anesthesia

    Science.gov (United States)

    Muniyappa, Reshma B.; Rajappa, Geetha C.; Govindswamy, Suresh; Thamanna, Prathima P.

    2016-01-01

    Background and Objective: Various adjuvants have been introduced to decrease the dose of volatile agents and their side effects. Dexmedetomidine a potent alpha-2 adrenoreceptor agonist is one such agent. Our objective is to assess the effect of preanesthetic dexmedetomidine on isoflurane consumption and its effect on intraoperative hemodynamic stability and recovery profile. Setting and Design: This prospective, randomized controlled, double-blind study was done in a tertiary care hospital. Materials and Methods: One hundred patients were randomly allocated into two groups. Group 1 received saline infusion and Group 2 received dexmedetomidine infusion in a dose of 1 μg/kg over 10 min given 15 min before induction. Vital parameters and bispectral index (BIS) values were noted throughout the surgery. Patients were induced and intubated as per the standard protocol and maintained with N2O: O2 = 1:1 mixture at 2 L/min and isoflurane concentration adjusted to achieve BIS values of 45–60. Demographic profile, hemodynamic variables, total isoflurane consumption, and recovery profile data were collected. Statistics: Independent t-test and Mann–Whitney U-test were used to compare the average anesthetic consumption, hemodynamics, and recovery profile between two groups. Results: End-tidal concentration and total isoflurane consumption in Group 2 were 0.56 ± 0.11 and 10.69 ± 3.01 mL, respectively, with P Preanesthetic bolus dose of dexmedetomidine is a useful adjuvant to reduce isoflurane consumption. PMID:27746567

  8. Optimizing computed tomography pulmonary angiography using right atrium bolus monitoring combined with spontaneous respiration

    Energy Technology Data Exchange (ETDEWEB)

    Min, Wang; Jian, Li; Rui, Zhai [Jining No. 1 People' s Hospital, Department of Computed Tomography, Jining City, ShanDong Province (China); Wen, Li [Jining No. 1 People' s Hospital, Department of Gastroenterology, Jining, ShanDong (China); Dai, Lun-Hou [Shandong Chest Hospital, Department of Radiology, Jinan, ShanDong (China)

    2015-09-15

    CT pulmonary angiography (CTPA) aims to provide pulmonary arterial opacification in the absence of significant pulmonary venous filling. This requires accurate timing of the imaging acquisition to ensure synchronization with the peak pulmonary artery contrast concentration. This study was designed to test the utility of right atrium (RA) monitoring in ensuring optimal timing of CTPA acquisition. Sixty patients referred for CTPA were divided into two groups. Group A (n = 30): CTPA was performed using bolus triggering from the pulmonary trunk, suspended respiration and 70 ml of contrast agent (CA). Group B (n = 30): CTPA image acquisition was triggered using RA monitoring with spontaneous respiration and 40 ml of CA. Image quality was compared. Subjective image quality, average CT values of pulmonary arteries and density difference between artery and vein pairs were significantly higher whereas CT values of pulmonary veins were significantly lower in group B (all P < 0.05). There was no significant difference between the groups in the proportion of subjects where sixth grade pulmonary arteries were opacified (P > 0.05). RA monitoring combined with spontaneous respiration to trigger image acquisition in CTPA produces optimal contrast enhancement in pulmonary arterial structures with minimal venous filling even with reduced doses of CA. (orig.)

  9. Thoracic pathologies on scout views and bolus tracking slices for computed tomographic cerebral angiography

    Energy Technology Data Exchange (ETDEWEB)

    Groth, M.; Fiehler, J.; Buhk, J.H. [University Medical Center Hamburg-Eppendorf (Germany). Dept. of Diagnostic and Interventional Neuroradiology; Henes, F.O. [University Medical Center Hamburg-Eppendorf (Germany). Dept. of Diagnostic and Interventional Radiology

    2015-08-15

    To evaluate the incidence of additional thoracic pathologic findings (TPF) detected on scout views and corresponding bolus tracking slices (SVBT) for computed tomographic cerebral angiography (CTCA) and to test the reliability and accuracy of these findings. The study collective included 505 consecutive patients who underwent multidetector CTCA. Appendant SVBT of all patients were reviewed for any pathologic findings and patient medical reports were analyzed, if any medical treatment was initiated for the detected pathologic findings. In 18 patients thoracic CT scans were performed in the same session. These were additionally reviewed by two blinded observers to test for intra- and interobserver reliability as well as for accuracy of detecting thoracic pathologies on SVBT. TPF were detected in 165 (33 %) SVBT. The five most common pathologic findings were: pleural effusion, 12 %; pneumonia, 8 %; atelectasis/dystelecatsis, 6 %; pericardial effusion, 2 % and elevated diaphragm, 1 %. For 48 % of these findings medical treatment was initiated. SVBT showed a sensitivity of 53 %, a specificity of 99 %, a positive predictive value of 89 %, a negative predictive value of 94 % and accuracy of 94 % for the detection of TPF. The intraobserver reliability was very good and the interobserver reliability showed moderate agreement. SVBT for CTCA should be reviewed with care by radiologists, since additional TPF can affect patient management. Nevertheless, despite a high specificity of SVBT for detecting TPF, an only moderate sensitivity has to be taken into account.

  10. Basal or bolus dose, which is the key factor in CSII?

    Institute of Scientific and Technical Information of China (English)

    YANG Nai-long; XUE Bing; LIN Peng

    2006-01-01

    Objective: To observe the value of HbA1c level evaluating the total daily basal insulin dose by continuous subcutaneous insulin infusion (CSII) in 268 patients with type 2 diabetes mellitus. Methods: 5-point capillary blood glucose was monitored in pre- and post-CSII and the insulin dose which could stabilize blood glucose was defmed as the total daily dose of insulin,including basal and bolus total dose. Correlation between HbA1c level and total daily dose of insulin in patients with type 2 diabetes mellitus was analyzed. Correlation between HbA1c level and 5-point capillary blood glucose was also analyzed. Results:Obvious correlation was observed between HbA1c level and the basal total daily dose of insulin if HbA1c was more than 9.3%(r=0.635, P<0.05). The average of 5-point capillary blood glucose was best correlated with HbA1c and fasting blood glucose next best. Conclusion: HbA1c level can forecast basal total daily dose of insulin in CSII.

  11. 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.

  12. Odd viscosity in two-dimensional incompressible fluids

    Science.gov (United States)

    Ganeshan, Sriram; Abanov, Alexander G.

    2017-09-01

    In this work, we present observable consequences of a parity-violating odd-viscosity term in incompressible 2+1D hydrodynamics. For boundary conditions depending on the velocity field (flow) alone we show that (i) the fluid flow quantified by the velocity field is independent of odd viscosity, (ii) the force acting on a closed contour is independent of odd viscosity, and (iii) the odd-viscosity part of torque on a closed contour is proportional to the rate of change of area enclosed by the contour with the proportionality constant being twice the odd viscosity. The last statement allows us to define a measurement protocol of odd viscostance in analogy to Hall resistance measurements. We also consider no-stress boundary conditions that explicitly depend on odd viscosity. A classic hydrodynamics problem with no-stress boundary conditions is that of a bubble in a planar Stokes flow. We solve this problem exactly for shear and hyperbolic flows and show that the steady-state shape of the bubble in the shear flow depends explicitly on the value of odd viscosity.

  13. 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.

  14. Effects of advanced carbohydrate counting guided by an automated bolus calculator in Type 1 diabetes mellitus (StenoABC)

    DEFF Research Database (Denmark)

    Hommel, E; Schmidt, S; Vistisen, D;

    2016-01-01

    -centre, investigator-initiated clinical study. We enrolled advanced carbohydrate counting-naïve adults with Type 1 diabetes and HbA1c levels 64-100 mmol/mol (8.0-11.3%), who were receiving multiple daily insulin injection therapy. In a 1:1-ratio, participants were randomized to receive training in either advanced......AIMS: To test whether concomitant use of an automated bolus calculator for people with Type 1 diabetes carrying out advanced carbohydrate counting would induce further improvements in metabolic control. METHODS: We conducted a 12-month, randomized, parallel-group, open-label, single...... carbohydrate counting using mental calculations (MC group) or advanced carbohydrate counting using an automated bolus calculator (ABC group) during a 3.5-h group training course. For 12 months after training, participants attended a specialized diabetes centre quarterly. The primary outcome was change in HbA1c...

  15. 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.

  16. Feasibility of test-bolus DCE-MRI using CAIPIRINHA-VIBE for the evaluation of pancreatic malignancies

    Energy Technology Data Exchange (ETDEWEB)

    Huh, Jimi; Seo, Nieun; Kim, Bohyun [University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Asan Medical Center, 88 Olympic-ro 43-gil, Songpa-gu, Seoul (Korea, Republic of); Choi, Yoonseok; Woo, Dong-Cheol; Lee, Chang Kyung [Asan Medical Center, Bioimaging Center, Asan Institute for Life Sciences, Seoul (Korea, Republic of); Kim, In Seong [Siemens Healthcare, Seoul (Korea, Republic of); Nickel, Dominik [Siemens Healthcare, Erlangen (Germany); Kim, Kyung Won [University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Asan Medical Center, 88 Olympic-ro 43-gil, Songpa-gu, Seoul (Korea, Republic of); Asan Medical Center, Bioimaging Center, Asan Institute for Life Sciences, Seoul (Korea, Republic of)

    2016-11-15

    To evaluate the feasibility of test-bolus dynamic contrast-enhanced (DCE) MRI with CAIPIRINHA-VIBE for pancreatic malignancies. Thirty-two patients underwent DCE-MRI with CAIPIRINHA-VIBE after injection of 2 mL gadolinium. From the resulting time-intensity curve (TIC), we estimated the arterial (AP) and portal venous phase (PVP) scan timing for subsequent multiphasic MRI. DCE-MRI perfusion maps were generated, and perfusion parameters were calculated. The image quality was rated on a 5-point scale (1: poor, 5: excellent). Goodness-of-fit of the TIC was evaluated by Pearson's χ{sup 2} test. Test-bolus DCE-MRIs with high temporal (3 s) and spatial resolution (1 x 1 x 4 mm{sup 3}) were acquired with good-quality perfusion maps of Ktrans and iAUC (mean score 4.313 ± 0.535 and 4.125 ± 0.554, respectively). The mean χ{sup 2} values for fitted TICs were 0.115 ± 0.082 for the pancreatic parenchyma and 0.784 ± 0.074 for pancreatic malignancies, indicating an acceptable goodness-of-fit. Test-bolus DCE-MRI was highly accurate in estimating the proper timing of AP (90.6 %) and PVP (100 %) of subsequent multiphasic MRI. Between pancreatic adenocarcinomas and neuroendocrine tumours, there were significant differences in the Ktrans (0.073 ± 0.058 vs. 0.308 ± 0.062, respectively; p = 0.007) and iAUC (1.501 ± 0.828 vs. 3.378 ± 0.378, respectively; p = 0.045). Test-bolus DCE-MRI using CAIPIRINHA-VIBE is feasible for incorporating perfusion analysis of pancreatic tumours into routine multiphasic MRI. (orig.)

  17. Model of the Glucose-Insulin-Glucagon Dynamics after Subcutaneous Administration of a Glucagon Rescue Bolus in Healthy Humans

    DEFF Research Database (Denmark)

    Wendt, Sabrina Lyngbye; Møller, Jan Kloppenborg; Haidar, Ahmad;

    In healthy individuals, insulin and glucagon work in a complex fashion to maintain blood glucose levels within a narrow range. This regulation is distorted in patients with diabetes. The hepatic glucose response due to an elevated glucagon level depends on the current insulin concentration and thus......IU/L). The model can be used for simulation of glucagon bolus strategies for treatment of hypoglycemia and for in silico simulation of dual-hormone artificial pancreas algorithms....

  18. Electron Conformal Radiotherapy for Post-Mastectomy Irradiation: A Bolus-Free, Multi-Energy, Multi-Segmented Field Algorithm

    Science.gov (United States)

    2005-08-01

    The radiation oncologist outlines the PTV, which is the target area that will be treated with electrons . Figure 2 .2 shows a clinica l example of...post-mastectomy clinica l cases. These particular cases were previously treated using bolus ECT . After the segmented-field ECT plans were developed...size. This data was collected by the medica l physics staff at M . D. Anderson during the machine commissioning proces s for a linear accelerator . 19 3

  19. Effects of intravenous bolus dosages of methylprednisolone and local radiation on renal allograft rejection and patient mortality

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, N.; Sreepada Rao, T.K.; Sakai, A.; Butt, K.H.; Kountz, S.L.

    1977-01-01

    One hundred and thirty of 179 rejection episodes encountered in 205 transplants were reversed by treatment with a bolus preparation of methylprednisolone. Ninety-six of these episodes also required an increase in oral prednisone dosage. No beneficial effect on over-all graft survival was noted, but a significant rise in the mortality, secondary to sepsis, was noted in those who received more than 5 grams of methylprednisolone. Local radiation to the graft did not contribute to better graft survival or mortality.

  20. Comparison of continuous infusion with intermittent bolus administration of cefotaxime on blood and cavity fluid drug concentrations in neonatal foals.

    Science.gov (United States)

    Hewson, J; Johnson, R; Arroyo, L G; Diaz-Mendez, A; Ruiz-López, J A; Gu, Y; del Castillo, J R E

    2013-02-01

    Healthy neonatal foals were treated with cefotaxime by bolus (40 mg/kg i.v. q6h for 12 doses; n=10) or by infusion (loading dose of 40 mg/kg i.v. followed by continuous infusion of a total daily dose of 160 mg/kg per 24 h for 3 days; n=5). Population pharmacokinetics was determined, and concentrations in cavity fluids were measured at steady state (72 h). Highest measured serum drug concentration in the bolus group was 88.09 μg/mL and minimum drug concentration (C(min)) was 0.78 μg/mL at 6-h postadministration (immediately before each next dose), whereas infusion resulted in a steady-state concentration of 16.10 μg/mL in the infusion group. Mean cefotaxime concentration in joint fluid at 72 h was higher (P=0.051) in the infusion group (5.02 μg/mL) compared to the bolus group (0.78 μg/mL). Drug concentration in CSF at 72 h was not different between groups (P=0.243) and was substantially lower than serum concentrations in either group. Insufficient data on pulmonary epithelial lining fluid were available to compare the methods of administration for cefotaxime in this cavity fluid. Results support continuous drug infusion over bolus dosing in the treatment for neonatal foal septicemia to optimize time that cefotaxime concentration exceeds the minimum inhibitory concentration of common equine pathogens.

  1. 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.

  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. 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.

  5. 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.

  6. 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.

  7. 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

  8. Effect of Electrohydraulic Discharge on Viscosity of Human Blood

    Directory of Open Access Journals (Sweden)

    G. M. El-Aragi

    2013-01-01

    Full Text Available Electrohydraulic plasma discharge is a novel technology with high efficiency and high speed and can generate chemically active species like free radicals, ions, atoms, and metastables, accompanied by ultraviolet light emission and shock pressure waves. The aim of this work is to examine the effect of electrohydraulic discharge (EHD system on viscosity of the human blood after different exposure time. The voltage pulsation introduces electric field and temperature jump and at the same time leads to haemolysis of the blood cells. The ratio of blood viscosity under the influence of magnetic field to the viscosity in the absence of magnetic field is directly proportional to the applied magnetic field .

  9. 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.

  10. Effect of viscosity on droplet-droplet collision outcome: Experimental study and numerical comparison

    Science.gov (United States)

    Gotaas, Cecilie; Havelka, Pavel; Jakobsen, Hugo A.; Svendsen, Hallvard F.; Hase, Matthias; Roth, Norbert; Weigand, Bernhard

    2007-10-01

    The influence of viscosity on droplet-droplet collision behavior at ambient conditions was studied experimentally and numerically. N-decane, monoethyleneglycol (MEG), diethyleneglycol (DEG), and triethyleneglycol were used as liquid phase providing viscosities in the range from 0.9to48mPas. Collision Weber numbers ranged approximately from 10 to 420. A direct numerical simulation code, based on the volume-of-fluid concept, was used for the simulations. Experimentally, observations of two droplet streams using a modified stroboscopic technique (aliasing method) were used to investigate the whole range of impact parameters during one experimental run. The experimental method has previously been verified for the water/air system [C. Gotaas et al., Phys. Fluids 19, 102105 (2007)]. In the present work, it was tested and validated for the n-decane/air system. Measured data agree well with those published in the literature. Well-defined regions of stretching separation and coalescence were identified, while reflexive separation regions were not found by using a single sinusoidal disturbance. However, the onset of reflexive separation was identified for MEG and DEG using an amplitude modulation technique. The results show that the criteria for onset of reflexive separation for viscous fluids provided by Y. I. Jiang et al. [J. Fluid Mech. 234, 177 (1992)] are not valid. This is consistent with the results given by K. D. Willis and M. Orme [Exp. Fluids 34, 28 (2003)]. A new empirical correlation for the onset of reflexive separation for high viscosity fluids is presented. The borders between coalescing and stretching separation were shifted toward higher Weber numbers with increasing viscosity. The lack of occurrence of reflexive separation for the single sinusoidal disturbance (small droplets), as well as the stretching separation boundary shift, can be explained by dissipation of collision kinetic energy in viscous flows inside the merged droplet after collision. Results

  11. Viscosity and haemodynamics in a late gestation rat feto-placental arterial network.

    Science.gov (United States)

    Bappoo, Nikhilesh; Kelsey, Lachlan J; Parker, Louis; Crough, Tim; Moran, Carmel M; Thomson, Adrian; Holmes, Megan C; Wyrwoll, Caitlin S; Doyle, Barry J

    2017-08-01

    The placenta is a transient organ which develops during pregnancy to provide haemotrophic support for healthy fetal growth and development. Fundamental to its function is the healthy development of vascular trees in the feto-placental arterial network. Despite the strong association of haemodynamics with vascular remodelling mechanisms, there is a lack of computational haemodynamic data that may improve our understanding of feto-placental physiology. The aim of this work was to create a comprehensive 3D computational fluid dynamics model of a substructure of the rat feto-placental arterial network and investigate the influence of viscosity on wall shear stress (WSS). Late gestation rat feto-placental arteries were perfused with radiopaque Microfil and scanned via micro-computed tomography to capture the feto-placental arterial geometry in 3D. A detailed description of rat fetal blood viscosity parameters was developed, and three different approaches to feto-placental haemodynamics were simulated in 3D using the finite volume method: Newtonian model, non-Newtonian Carreau-Yasuda model and Fåhræus-Lindqvist effect model. Significant variability in WSS was observed between different viscosity models. The physiologically-realistic simulations using the Fåhræus-Lindqvist effect and rat fetal blood estimates of viscosity revealed detailed patterns of WSS throughout the arterial network. We found WSS gradients at bifurcation regions, which may contribute to vessel enlargement, and sprouting and pruning during angiogenesis. This simulation of feto-placental haemodynamics shows the heterogeneous WSS distribution throughout the network and demonstrates the ability to determine physiologically-relevant WSS magnitudes, patterns and gradients. This model will help advance our understanding of vascular physiology and remodelling in the feto-placental network.

  12. THE INFLUENCE OF PRESSURE-DEPENDENT VISCOSITY ON THE THERMAL EVOLUTION OF SUPER-EARTHS

    Energy Technology Data Exchange (ETDEWEB)

    Stamenkovic, Vlada; Noack, Lena; Spohn, Tilman [Institute of Planetology, Westfaelische Wilhelms-Universitaet Muenster, Wilhelm-Klemm-Str. 10, 48149 Muenster (Germany); Breuer, Doris, E-mail: Vlada.Stamenkovic@dlr.de, E-mail: Lena.Noack@dlr.de, E-mail: Doris.Breuer@dlr.de, E-mail: Tilman.Spohn@dlr.de [Institute of Planetary Research, German Aerospace Center DLR, Rutherfordstrasse 2, 12489 Berlin (Germany)

    2012-03-20

    We study the thermal evolution of super-Earths with a one-dimensional (1D) parameterized convection model that has been adopted to account for a strong pressure dependence of the viscosity. A comparison with a 2D spherical convection model shows that the derived parameterization satisfactorily represents the main characteristics of the thermal evolution of massive rocky planets. We find that the pressure dependence of the viscosity strongly influences the thermal evolution of super-Earths-resulting in a highly sluggish convection regime in the lower mantles of those planets. Depending on the effective activation volume and for cooler initial conditions, we observe with growing planetary mass even the formation of a conductive lid above the core-mantle boundary (CMB), a so-called CMB-lid. For initially molten planets our results suggest no CMB-lids but instead a hot lower mantle and core as well as sluggish lower mantle convection. This implies that the initial interior temperatures, especially in the lower mantle, become crucial for the thermal evolution-the thermostat effect suggested to regulate the interior temperatures in terrestrial planets does not work for massive planets if the viscosity is strongly pressure dependent. The sluggish convection and the potential formation of the CMB-lid reduce the convective vigor throughout the mantle, thereby affecting convective stresses, lithospheric thicknesses, and heat fluxes. The pressure dependence of the viscosity may therefore also strongly affect the propensity of plate tectonics, volcanic activity, and the generation of a magnetic field of super-Earths.

  13. Densities, viscosities, speed of sound, and IR spectroscopic studies of binary mixtures of tert-butyl acetate with benzene, methylbenzene, and ethylbenzene at T = (298.15 and 308.15) K

    Energy Technology Data Exchange (ETDEWEB)

    Hasan, Mehdi, E-mail: mihasan@rediffmail.com [P.G. Department of Physical Chemistry, M.S.G. College, Malegaon Camp 423 105 (India); Sawant, Arun B. [P.G. Department of Physical Chemistry, M.S.G. College, Malegaon Camp 423 105 (India); Sawant, Rajashri B. [P.G. Department of Physical Chemistry, M.S.G. College, Malegaon Camp 423 105 (India); Department of Chemistry, S.P.H. Mahila College, Malegaon Camp 423 105 (India); Loke, Pratibha G. [P.G. Department of Physical Chemistry, M.S.G. College, Malegaon Camp 423 105 (India); Department of Physics, G.M.D. Arts, B.W. Commerce and Science College, Sinnar (India)

    2011-09-15

    Highlights: > Densities, viscosities and speed of sound for the benzene + benzenes with tert-butyl acetate at T = (298.15 and 308.15) K is reported. > IR spectra at room temperature are recorded to support observations from other studies. > The experimental observations are explained on the basis of molecular interaction between the constituent binaries. - Abstract: Densities, viscosities, speed of sound, and IR spectroscopy of binary mixtures of tert-butyl acetate (TBA) with benzene, methylbenzene, and ethylbenzene have been measured over the entire range of composition, at (298.15 and 308.15) K and at atmospheric pressure. From the experimental values of density, viscosity, speed of sound, and IR spectroscopy; excess molar volumes V{sup E}, deviations in viscosity {Delta}{eta}, deviations in isentropic compressibility {Delta}{kappa}{sub s} and stretching frequency {nu} have been calculated. The excess molar volumes and deviations in isentropic compressibility are positive for the binaries studied over the whole composition, while deviations in viscosities are negative for the binary mixtures. The excess molar volumes, deviations in viscosity, and deviations in isentropic compressibility have been fitted to the Redlich-Kister polynomial equation. The Jouyban-Acree model is used to correlate the experimental values of density, viscosity, and speed of sound.

  14. Spontaneous and bolus-induced motility in the chronically obstructed guinea-pig small intestine in vitro.

    Science.gov (United States)

    Storkholm, Jan Henrik; Zhao, Jingbo; Villadsen, Gerda E; Gregersen, Hans

    2008-02-01

    Partial obstruction of the small intestine results in dysmotility and morphometric changes proximal to the site of obstruction. However, our understanding of the relation between the morphometric remodeling and change in the motility pattern during chronic obstruction is sparse. The aim of this study was to investigate the effect of partial chronic intestinal obstruction on motility, morphology, and collagen content proximal and distal to the site of obstruction. Twenty guinea-pigs with partial intestinal obstruction and eight sham-operated controls lived for four weeks. Spontaneous and bolus-induced motility was recorded in isolated intestinal segments proximal and distal to the site of obstruction using a perfused low-compliance pressure-measuring system in vitro. After the motility experiments, the specimens were fixed at 2 kPa luminal distension pressure and sampled for histomorphometric determination of luminal radius, layer thickness, and wall thickness. Total wall collagen was also determined. The area under the curve (AUC) of spontaneous contractions and the amplitude, frequency, and AUC for the bolus-induced motility were higher in the proximal segments of the banded animals compared to distal segments and to the intestinal segments in the control animals (P thickness ratio was lowest in the proximal segments of the obstructed animals (P thickness ratio showed a strong association (r = 0.97 for control, and r = 0.99 for obstruction, P thickness ratio and bolus-induced motility.

  15. [Quality of life and hypoglycemia burden in patients with type 2 diabetes mellitus on basal-bolus insulin therapy].

    Science.gov (United States)

    Ionova, T I; Odin, V I; Nikitina, T P; Kurbatova, K A

    2014-01-01

    This paper presents the results of the observational program "Parameters of life quality, symptoms of hypoglycemia and treatment satisfaction in patients with type 2 diabetes mellitus on basal-bolus insulin therapy" (2012-2014). The analysis included 1000 patients. It showed that their quality of life was below that of the general population due to compromised physical, role physical, and role emotional functioning (p diabetes mellitus on basal-bolus insulin therapy. They are characterized by impaired physical, psychological, and social functioning compared with the patients without hypoglycemic episodes (p quality of life was much worse (ES = 0.22-0.51). The profile of hypoglycemic episodes differed in different forms of hypoglycemia. The spectrum of symptoms and problems related to hypoglycemia was broader in patients with severe and/or nocturnal hypoglycemia. Patients free from hypoglycemia were less afraid of it than those used to have hypoglycemic episodes (p quality of life and hypoglycemia-related symptoms in patients with type 2 diabetes mellitus on basal-bolus insulin therapy allows for comprehensive estimation of the effectiveness of therapy on an individual basis.

  16. A fully coupled bolus-esophageal-gastric model for esophageal emptying based on the immersed boundary method

    Science.gov (United States)

    Kou, Wenjun; Pandolfino, John E.; Kahrilas, Peter J.; Patankar, Neelesh A.

    2016-11-01

    In this work, we develop a fully coupled bolus-esophageal-gastric model to study esophageal emptying based on the immersed boundary method. The model includes an esophageal segment, an ellipsoid-shaped stomach, and a bolus. It can easily handle the passive and active function of the lower esophageal sphincter (LES). Two groups of case studies are presented. The first group is about the influence from tissue anisotropy. Simulation shows that the weaker (or more compliant) part suffers from a higher wall shear stress and higher pressure load when the bolus is filled in and emptied from the LES segment. This implies a degradation cycle in which a weaker tissue becomes much weaker due to an increased load, a possible pathway to the esophageal lower diverticulum. The second group is about bulge formation resulting from asymmetric anatomy and a compliant LES. In particular, we find a right bulge tends to develop for a compliant LES. The bulge is most pronounced with a highest stiffness of the gastric wall. This implies that the competition between the LES stiffness and gastric wall stiffness might be another factor related to the esophageal lower diverticulum. The support of Grant R01 DK56033 and R01 DK079902 from NIH is gratefully acknowledged.

  17. Increased pulsatile movement of the hindbrain in syringomyelia associated with the Chiari malformation: cine-MRI with presaturation bolus tracking

    Energy Technology Data Exchange (ETDEWEB)

    Terae, S. [Hokkaido Univ. School of Medicine, Sapporo (Japan). Dept. of Radiology; Miyasaka, K. [Hokkaido Univ. School of Medicine, Sapporo (Japan). Dept. of Radiology; Abe, S. [Hokkaido Univ. School of Medicine, Sapporo (Japan). Dept. of Radiology; Abe, H.; Tashiro, K. [Hokkaido Univ. School of Medicine, Sapporo (Japan). Dept. of Neurology

    1994-02-01

    Cine-MRI with presaturation bolus tracking was used in patients with syringomyelia associated with a Chiari malformation to study pulsatile movement of the hindbrain, cervical spinal cord, cerebrospinal fluid and the fluid within the syrinx. Nine patients had 13 examinations, 6 preoperative, 3 after syringosubarachnoid shunting and 4 after posterior fossa decompression. Five controls were also examined. Dynamic display of the acquired images demonstrated downward displacement of the presaturation bolus on the cerebellar tonsils and medulla oblongata (or upper cervical cord) at the C1 level in all preoperative examinations and in two patients after syringo-subarachnoid shunting but with residual foramen magnum obstruction. Downward displacement of the bolus on the cervical spinal cord was also demonstrated in 7 examinations, but not observed in the controls. Thus, the hindbrain-spinal cord axis showed larger pulsatile movements in patients with foramen magnum obstruction. Based on these observations and a review of the literature, a new theory on the mode of extension of syringomyelia, emphasising the role of increased pulsatile movement of the hindbrain-spinal cord axis is proposed: that the pulsatile movements, together with a one-way valve mechanism in the syrinx cavity act as a ``vacuum-pump`` to enlarge the syrinx. (orig.)

  18. 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.

  19. 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)

  20. 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%.