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.

Determination of the density and the viscosities of biodiesel-diesel fuel blends

Energy Technology Data Exchange (ETDEWEB)

Alptekin, Ertan; Canakci, Mustafa [Department of Mechanical Education, Kocaeli University, 41380 Kocaeli (Turkey); Alternative Fuels R and D Center, Kocaeli University, 41040 Kocaeli (Turkey)

2008-12-15

In this study, commercially available two different diesel fuels were blended with the biodiesels produced from six different vegetable oils (sunflower, canola, soybean, cottonseed, corn oils and waste palm oil). The blends (B2, B5, B10, B20, B50 and B75) were prepared on a volume basis. The key fuel properties such as density and viscosities of the blends were measured by following ASTM test methods. Generalized equations for predicting the density and viscosities for the blends were given and a mixing equation, originally proposed by Arrhenius and described by Grunberg and Nissan, was used to predict the viscosities of the blends. For all blends, it was found that there is an excellent agreement between the measured and estimated values of the density and viscosities. According to the results, the density and viscosities of the blends increased with the increase of biodiesel concentration in the fuel blend. (author)

Temperature Dependence on Density, Viscosity, and Electrical Conductivity of Ionic Liquid 1-Ethyl-3-Methylimidazolium Fluoride

Directory of Open Access Journals (Sweden)

Fengguo Liu

2018-03-01

Full Text Available Ionic liquids are considered environmentally friendly media for various industrial applications. Basic data on physicochemical properties are significant for a new material, in terms of developing its potential applications. In this work, 1-ethyl-3-methylimidazolium fluoride ([EMIm]F ionic liquid was synthesized via an anion metathesis process. Physical properties including the density, viscosity, electrical conductivity, and thermal stability of the product were measured. The results show that the density of [EMIm]F decreases linearly with temperature increases, while dynamic viscosity decreases rapidly below 320 K and the temperature dependence of electrical conductivity is in accordance with the VFT (Vogel–Fulcher–Tammann equation. The temperature dependence of the density, conductivity, and viscosity of [EMIm]F can be expressed via the following equations: ρ = 1.516 − 1.22 × 10−3 T, σm = 4417.1exp[−953.17/(T − 166.65] and η = 2.07 × 10−7exp(−5.39 × 104/T, respectively. [EMIm]F exhibited no clear melting point. However, its glass transition point and decomposition temperature are −71.3 °C and 135 °C, respectively.

Viscosity and Liquid Density of Asymmetric n-Alkane Mixtures: Measurement and Modelling

DEFF Research Database (Denmark)

Queimada, António J.; Marrucho, Isabel M.; Coutinho, João A.P.

2005-01-01

Viscosity and liquid density Measurements were performed, at atmospheric pressure. in pure and mixed n-decane. n-eicosane, n-docosane, and n-tetracosane from 293.15 K (or above the melting point) up to 343.15 K. The viscosity was determined with a rolling ball viscometer and liquid densities...... with a vibrating U-tube densimeter. Pure component results agreed, oil average, with literature values within 0.2% for liquid density and 3% for viscosity. The measured data were used to evaluate the performance of two models for their predictions: the friction theory coupled with the Peng-Robinson equation...... of state and a corresponding states model recently proposed for surface tension, viscosity, vapor pressure, and liquid densities of the series of n-alkanes. Advantages and shortcoming of these models are discussed....

Measuring the density and viscosity of H2S-loaded aqueous methyldiethanolamine solution

International Nuclear Information System (INIS)

Shokouhi, Mohammad; Ahmadi, Reza

2016-01-01

Highlights: • Measurement solubility of H 2 S in 46.78 mass% MDEA aqueous solutions. • Measurement density of H 2 S loaded of MDEA aqueous solution. • Measurement viscosity of H 2 S loaded of MDEA aqueous solution. • Correlation of the density and viscosity of H 2 S loaded of MDEA aqueous solution using modified setchenow equation. - Abstract: The density and viscosity of H 2 S-loaded aqueous 46.78 mass% methyldiethanolamine solution were experimentally measured accompanied with the solubility of H 2 S at temperatures (313.15, 328.15 and 343.15) K, pressures from vapor pressure of fresh solution up to 1.0 MPa and loadings up to 1.00 mol of H 2 S per 1 mol of amine. All experimental trials have been carried out using the new setup developed in our laboratory. It was observed that both density and viscosity of mixtures decrease by increasing temperature and density increase by increasing acid gas solubility (loading) by about 4.7%, whereas viscosity has a complicated behavior with H 2 S solubility. Viscosity decreases by increasing acid gas solubility (loading) at 313.15 K by about 20.6% and at 328.15 K by about 15.0%, but it is comparable at 343.15 K in terms of H 2 S solubility. Finally, the experimental density and viscosity data correlated using Modified Setchenow equation.

Experimental study of electric conductivity, density and viscosity of Wood's alloy

International Nuclear Information System (INIS)

Kazandzhan, B.I.; Matveev, V.M.; Savich, T.B.; Umarov, A.M.

1989-01-01

Electric conductivity, density and kinematic viscosity of commercially pure Wood's alloy are obtained in a wide temperature range. Electric conductivity and density are investigated from the room temperature to 1000 K. Measurements of kinematic viscosity are carried out from 372 to 1000 K by means of torsional vibrations method using informatiom computer system permitting to automate data acquisition and processing and to increase the measurement accuracy. On the basis of analysis the character of electric conductivity and kinematic viscosity polyterms Wood's alloy liquidus and solidus temperatures are estimated

Viscosity and density tables of sodium chloride solutions

Energy Technology Data Exchange (ETDEWEB)

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

1977-04-01

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

Density, excess properties, electrical conductivity and viscosity of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide + γ-butyrolactone binary mixtures

International Nuclear Information System (INIS)

Vraneš, Milan; Papović, Snežana; Tot, Aleksandar; Zec, Nebojša; Gadžurić, Slobodan

2014-01-01

Highlights: • Densities of [bmim][NTf 2 ] mixtures with γ-butyrolactone were measured. • Excess properties were calculated. • Nature of interactions between IL and GBL were discussed. • Specific conductivity and viscosity were also measured. • Walden plot is presented. - Abstract: Density, electrical conductivity and viscosity of binary liquid mixtures of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [bmim][NTf 2 ], with γ-butyrolactone (GBL) were measured at temperatures from (293.15 to 323.15) K and at atmospheric pressure over the whole composition range. Excess molar volumes have been calculated from the experimental densities and were fitted with Redlich–Kister polynomial equation. Other volumetric properties, such as isobaric thermal expansion coefficients, partial molar volumes, apparent molar volumes and partial molar volumes at infinite dilution have been also calculated, in order to obtain information about interactions between GBL and selected ionic liquid

An Investigation of Viscosities, Calorific Values and Densities of Binary Biofuel Blends

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Che Mat Sharzali

2017-01-01

Full Text Available Straight vegetable oil (SVO biofuel is a promising alternative to petroleum diesel fuel primarily due to its comparable physical properties to that of petroleum diesel fuel. However, the relatively higher viscosity of SVO limits its direct application in diesel engine. To resolve this issue, binary biofuel blends was introduced in this study to reduce the viscosity of SVO. In this work, a novel biofuel namely Melaleuca Cajuputi oil (MCO was used and blended with refined palm oil (RPO. A total of four blends with the mixing ratios of 20%, 40%, 50% and 60% of MCO were prepared. Various key properties of dynamic viscosity, calorific value and density of the blends were measured and benchmarked against the biodiesel standards based on ASTM D6751. It was found that viscosity and density of the blends decreased with the increase of MCO fraction. Meanwhile, the calorific value of the blends increased linearly as the MCO fraction increased. The blend of 40RPO60MCO was found to have comparable key properties of viscosity, calorific value and density to those of petroleum diesel fuel and ASTM D6751 standard.

REFERENCE ON THERMOPHYSICAL PROPERTIES: DENSITY AND VISCOSITY OF WATER FOR ATMOSPHERIC PRESSURE

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Elin Yusibani

2016-09-01

Full Text Available A reference on thermophysical properties, density and viscosity, for water at atmospheric pressure has been developed in MS Excel (as a macros. Patterson’s density equations and Kestin’s viscosity equations have been chosen as a basic equation in the VBA programming as a user-defined function. These results have been compared with REFPROF as a wellknow standart reference

Estimated Viscosities and Thermal Conductivities of Gases at High Temperatures

Science.gov (United States)

Svehla, Roger A.

1962-01-01

Viscosities and thermal conductivities, suitable for heat-transfer calculations, were estimated for about 200 gases in the ground state from 100 to 5000 K and 1-atmosphere pressure. Free radicals were included, but excited states and ions were not. Calculations for the transport coefficients were based upon the Lennard-Jones (12-6) potential for all gases. This potential was selected because: (1) It is one of the most realistic models available and (2) intermolecular force constants can be estimated from physical properties or by other techniques when experimental data are not available; such methods for estimating force constants are not as readily available for other potentials. When experimental viscosity data were available, they were used to obtain the force constants; otherwise the constants were estimated. These constants were then used to calculate both the viscosities and thermal conductivities tabulated in this report. For thermal conductivities of polyatomic gases an Eucken-type correction was made to correct for exchange between internal and translational energies. Though this correction may be rather poor at low temperatures, it becomes more satisfactory with increasing temperature. It was not possible to obtain force constants from experimental thermal conductivity data except for the inert atoms, because most conductivity data are available at low temperatures only (200 to 400 K), the temperature range where the Eucken correction is probably most in error. However, if the same set of force constants is used for both viscosity and thermal conductivity, there is a large degree of cancellation of error when these properties are used in heat-transfer equations such as the Dittus-Boelter equation. It is therefore concluded that the properties tabulated in this report are suitable for heat-transfer calculations of gaseous systems.

Options for refractive index and viscosity matching to study variable density flows

Science.gov (United States)

Clément, Simon A.; Guillemain, Anaïs; McCleney, Amy B.; Bardet, Philippe M.

2018-02-01

Variable density flows are often studied by mixing two miscible aqueous solutions of different densities. To perform optical diagnostics in such environments, the refractive index of the fluids must be matched, which can be achieved by carefully choosing the two solutes and the concentration of the solutions. To separate the effects of buoyancy forces and viscosity variations, it is desirable to match the viscosity of the two solutions in addition to their refractive index. In this manuscript, several pairs of index matched fluids are compared in terms of viscosity matching, monetary cost, and practical use. Two fluid pairs are studied in detail, with two aqueous solutions (binary solutions of water and a salt or alcohol) mixed into a ternary solution. In each case: an aqueous solution of isopropanol mixed with an aqueous solution of sodium chloride (NaCl) and an aqueous solution of glycerol mixed with an aqueous solution of sodium sulfate (Na_2SO_4). The first fluid pair allows reaching high-density differences at low cost, but brings a large difference in dynamic viscosity. The second allows matching dynamic viscosity and refractive index simultaneously, at reasonable cost. For each of these four solutes, the density, kinematic viscosity, and refractive index are measured versus concentration and temperature, as well as wavelength for the refractive index. To investigate non-linear effects when two index-matched, binary solutions are mixed, the ternary solutions formed are also analyzed. Results show that density and refractive index follow a linear variation with concentration. However, the viscosity of the isopropanol and NaCl pair deviates from the linear law and has to be considered. Empirical correlations and their coefficients are given to create index-matched fluids at a chosen temperature and wavelength. Finally, the effectiveness of the refractive index matching is illustrated with particle image velocimetry measurements performed for a buoyant jet in a

Characterizing Vibrating Cantilevers for Liquid Viscosity and Density Sensing

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Bernhard Jakoby

2008-10-01

Full Text Available Miniaturized liquid sensors are essential devices in online process or condition monitoring. In case of viscosity and density sensing, microacoustic sensors such as quartz crystal resonators or SAW devices have proved particularly useful. However, these devices basically measure a thin-film viscosity, which is often not comparable to the macroscopic parameters probed by conventional viscometers. Miniaturized cantilever-based devices are interesting alternatives for such applications, but here the interaction between the liquid and the oscillating beam is more involved. In our contribution, we describe a measurement setup, which allows the investigation of this interaction for different beam cross-sections. We present an analytical model based on an approximation of the immersed cantilever as an oscillating sphere comprising the effective mass and the intrinsic damping of the cantilever and additional mass and damping due to the liquid loading. The model parameters are obtained from measurements with well-known sample liquids by a curve fitting procedure. Finally, we present the measurement of viscosity and density of an unknown sample liquid, demonstrating the feasibility of the model.

Mathematical modelling of pasta dough dynamic viscosity, thermal conductivity and diffusivity

Directory of Open Access Journals (Sweden)

Andrei Ionuţ SIMION

2015-08-01

Full Text Available This work aimed to study the mathematical variation of three main thermodynamic properties (dynamic viscosity, thermal conductivity and thermal diffusivity of pasta dough obtained by mixing wheat semolina and water with dough humidity and deformation speed (for dynamic viscosity, respectively with dough humidity and temperature (for thermal diffusivity and conductivity. The realized regression analysis of existing graphical data led to the development of mathematical models with a high degree of accuracy. The employed statistical tests (least squares, relative error and analysis of variance revealed that the obtained equations are able to describe and predict the tendency of the dough thermodynamic properties.

Effect of ethanol, dry extract and reducing sugars on density and viscosity of Brazilian red wines.

Science.gov (United States)

Neto, Flávia S P P; de Castilhos, Maurício B M; Telis, Vânia R N; Telis-Romero, Javier

2015-05-01

Density and viscosity are properties that exert great influence on the body of wines. The present work aimed to evaluate the influence of the alcoholic content, dry extract, and reducing sugar content on density and viscosity of commercial dry red wines at different temperatures. The rheological assays were carried out on a controlled stress rheometer, using concentric cylinder geometry at seven temperatures (2, 8, 14, 16, 18, 20 and 26 °C). Wine viscosity decreased with increasing temperature and density was directly related to the wine alcohol content, whereas viscosity was closely linked to the dry extract. Reducing sugars did not influence viscosity or density. Wines produced from Italian grapes were presented as full-bodied with higher values for density and viscosity, which was linked to the higher alcohol content and dry extract, respectively. The results highlighted the major effects of certain physicochemical properties on the physical properties of wines, which in turn is important for guiding sensory assessments. © 2014 Society of Chemical Industry.

An experimental study on thermal conductivity and viscosity of nanofluids containing carbon nanotubes

Science.gov (United States)

2014-01-01

Recently, there has been considerable interest in the use of nanofluids for enhancing thermal performance. It has been shown that carbon nanotubes (CNTs) are capable of enhancing the thermal performance of conventional working liquids. Although much work has been devoted on the impact of CNT concentrations on the thermo-physical properties of nanofluids, the effects of preparation methods on the stability, thermal conductivity and viscosity of CNT suspensions are not well understood. This study is focused on providing experimental data on the effects of ultrasonication, temperature and surfactant on the thermo-physical properties of multi-walled carbon nanotube (MWCNT) nanofluids. Three types of surfactants were used in the experiments, namely, gum arabic (GA), sodium dodecylbenzene sulfonate (SDBS) and sodium dodecyl sulfate (SDS). The thermal conductivity and viscosity of the nanofluid suspensions were measured at various temperatures. The results showed that the use of GA in the nanofluid leads to superior thermal conductivity compared to the use of SDBS and SDS. With distilled water as the base liquid, the samples were prepared with 0.5 wt.% MWCNTs and 0.25% GA and sonicated at various times. The results showed that the sonication time influences the thermal conductivity, viscosity and dispersion of nanofluids. The thermal conductivity of nanofluids was typically enhanced with an increase in temperature and sonication time. In the present study, the maximum thermal conductivity enhancement was found to be 22.31% (the ratio of 1.22) at temperature of 45°C and sonication time of 40 min. The viscosity of nanofluids exhibited non-Newtonian shear-thinning behaviour. It was found that the viscosity of MWCNT nanofluids increases to a maximum value at a sonication time of 7 min and subsequently decreases with a further increase in sonication time. The presented data clearly indicated that the viscosity and thermal conductivity of nanofluids are influenced by the

Viscosity and attenuation of sound wave in high density deuterium

International Nuclear Information System (INIS)

Inoue, Kazuko; Ariyasu, Tomio

1985-01-01

The penetration of low frequency sound wave into the fuel deuterium is discussed as for laser fusion. The sound velocity and the attenuation constant due to viscosity are calculated for high density (n = 10 24 -- 10 27 cm -3 , T = 10 -1 -- 10 4 eV) deuterium. The shear viscosity of free electron gas and the bulk viscosity due to ion-ion interaction mainly contribute to the attenuation of sound wave. The sound wave of the frequency below 10 10 Hz can easily penetrate through the compressed fuel deuterium of diameter 1 -- 10 3 μm. (author)

Thermal conductivity as influenced by the temperature and apparent viscosity of dairy products.

Science.gov (United States)

Gonçalves, B J; Pereira, C G; Lago, A M T; Gonçalves, C S; Giarola, T M O; Abreu, L R; Resende, J V

2017-05-01

This study aimed to evaluate the rheological behavior and thermal conductivity of dairy products, composed of the same chemical components but with different formulations, as a function of temperature. Subsequently, thermal conductivity was related to the apparent viscosity of yogurt, fermented dairy beverage, and fermented milk. Thermal conductivity measures and rheological tests were performed at 5, 10, 15, 20, and 25°C using linear probe heating and an oscillatory rheometer with concentric cylinder geometry, respectively. The results were compared with those calculated using the parallel, series, and Maxwell-Eucken models as a function of temperature, and the discrepancies in the results are discussed. Linear equations were fitted to evaluate the influence of temperature on the thermal conductivity of the dairy products. The rheological behavior, specifically apparent viscosity versus shear rate, was influenced by temperature. Herschel-Bulkley, power law, and Newton's law models were used to fit the experimental data. The Herschel-Bulkley model best described the adjustments for yogurt, the power law model did so for fermented dairy beverages, and Newton's law model did so for fermented milk and was then used to determine the rheological parameters. Fermented milk showed a Newtonian trend, whereas yogurt and fermented dairy beverage were shear thinning. Apparent viscosity was correlated with temperature by the Arrhenius equation. The formulation influenced the effective thermal conductivity. The relationship between the 2 properties was established by fixing the temperature and expressing conductivity as a function of apparent viscosity. Thermal conductivity increased with viscosity and decreased with increasing temperature. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Experimental density and viscosity measurements of di(2ethylhexyl)sebacate at high pressure

International Nuclear Information System (INIS)

Paredes, Xavier; Fandino, Olivia; Pensado, Alfonso S.; Comunas, Maria J.P.; Fernandez, Josefa

2012-01-01

Highlights: → We measure viscosities for di(2-ethylhexyl)sebacate from (298.15 to 398.15) K and up to 60 MPa. → We measure densities for DEHS from (298.15 to 373.15) K and from (0.1 to 60) MPa. → The reported and lit. data were used in a viscosity correlation from (273 to 491) K and up to 1.1 GPa. → This correlation could be used in industrial equipment that operate at high pressures. - Abstract: Experimental densities and dynamic viscosities of di(2-ethylhexyl)sebacate (DEHS) are the object of study in this work. DEHS could be a useful industrial reference fluid for moderately high viscosity at high pressures as it is often used as a pressure transmitting fluid. At atmospheric pressure the density and viscosity measurements have been performed in a rotational SVM 3000 Stabinger viscometer from (273.15 to 373.15) K, whereas from (0.1 to 60) MPa and from (298.15 to 398.15) K an automated Anton Paar DMA HPM vibrating-tube densimeter, and a high-pressure rolling-ball viscometer were used. Several Vogel-Fulcher-Tammann type equations were used to fit the experimental values of viscosity to the pressure and temperature. The measured viscosity data have been used together with previous data found in the literature to establish a correlation of the viscosity surface η(T, p) of DEHS, covering a temperature range from (273 to 491) K and pressure up to 1.1 GPa. This correlation could be used in industrial equipment like viscometers and other devices that operate at high pressures. Our viscosity data have also been fitted as a function of temperature and volume to the thermodynamic scaling model of Roland et al. [C.M. Roland, S. Bair, R. Casalini, J. Chem. Phys. 125 (2006) 124508].

MHD natural convection from a heated vertical wavy surface with variable viscosity and thermal conductivity

International Nuclear Information System (INIS)

Choudhury, M.; Hazarika, G.C.; Sibanda, P.

2013-01-01

We investigate the effects of temperature dependent viscosity and thermal conductivity on natural convection flow of a viscous incompressible electrically conducting fluid along a vertical wavy surface. The flow is permeated by uniform transverse magnetic field. The fluid viscosity and thermal conductivity are assumed to vary as inverse linear functions of temperature. The coupled non-linear systems of partial differential equations are solved using the finite difference method. The effects of variable viscosity parameter, variable thermal conductivity parameter and magnetic parameter on the flow field and the heat transfer characteristics are discussed and shown graphically. (author)

Simultaneous viscosity and density measurement of small volumes of liquids using a vibrating microcantilever.

Science.gov (United States)

Payam, A F; Trewby, W; Voïtchovsky, K

2017-05-02

Many industrial and technological applications require precise determination of the viscosity and density of liquids. Such measurements can be time consuming and often require sampling substantial amounts of the liquid. These problems can partly be overcome with the use of microcantilevers but most existing methods depend on the specific geometry and properties of the cantilever, which renders simple, accurate measurement difficult. Here we present a new approach able to simultaneously quantify both the density and the viscosity of microliters of liquids. The method, based solely on the measurement of two characteristic frequencies of an immersed microcantilever, is completely independent of the choice of a cantilever. We derive analytical expressions for the liquid's density and viscosity and validate our approach with several simple liquids and different cantilevers. Application of our model to non-Newtonian fluids shows that the calculated viscosities are remarkably robust when compared to measurements obtained from a standard rheometer. However, the results become increasingly dependent on the cantilever geometry as the frequency-dependent nature of the liquid's viscosity becomes more significant.

Separation of density and viscosity influence on liquid-loaded surface acoustic wave devices

Science.gov (United States)

Herrmann, F.; Hahn, D.; Büttgenbach, S.

1999-05-01

Love-mode sensors are reported for separate measurement of liquid density and viscosity. They combine the general merits of Love-mode devices, e.g., ease of sensitivity adjustment and robustness, with a highly effective procedure of separate determination of liquid density and viscosity. A model is proposed to describe the frequency response of the devices to liquid loading. Moreover, design rules are given for further optimization and sensitivity enhancement.

A MEMS Resonant Sensor to Measure Fluid Density and Viscosity under Flexural and Torsional Vibrating Modes

Directory of Open Access Journals (Sweden)

Libo Zhao

2016-06-01

Full Text Available Methods to calculate fluid density and viscosity using a micro-cantilever and based on the resonance principle were put forward. Their measuring mechanisms were analyzed and the theoretical equations to calculate the density and viscosity were deduced. The fluid-solid coupling simulations were completed for the micro-cantilevers with different shapes. The sensing chips with micro-cantilevers were designed based on the simulation results and fabricated using the micro electromechanical systems (MEMS technology. Finally, the MEMS resonant sensor was packaged with the sensing chip to measure the densities and viscosities of eight different fluids under the flexural and torsional vibrating modes separately. The relative errors of the measured densities from 600 kg/m3 to 900 kg/m3 and viscosities from 200 μPa·s to 1000 μPa·s were calculated and analyzed with different microcantilevers under various vibrating modes. The experimental results showed that the effects of the shape and vibrating mode of micro-cantilever on the measurement accuracies of fluid density and viscosity were analyzed in detail.

Prediction models for density and viscosity of biodiesel and their effects on fuel supply system in CI engines

Energy Technology Data Exchange (ETDEWEB)

Tesfa, B.; Mishra, R.; Gu, F. [Computing and Engineering, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH (United Kingdom); Powles, N. [Chemistry and Forensic Science, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH (United Kingdom)

2010-12-15

Biodiesel is a promising non-toxic and biodegradable alternative fuel used in the transport sector. Nevertheless, the higher viscosity and density of biodiesel poses some acute problems when it is used it in unmodified engine. Taking this into consideration, this study has been focused towards two objectives. The first objective is to identify the effect of temperature on density and viscosity for a variety of biodiesels and also to develop a correlation between density and viscosity for these biodiesels. The second objective is to investigate and quantify the effects of density and viscosity of the biodiesels and their blends on various components of the engine fuel supply system such as fuel pump, fuel filters and fuel injector. To achieve first objective density and viscosity of rapeseed oil biodiesel, corn oil biodiesel and waste oil biodiesel blends (0B, 5B, 10B, 20B, 50B, 75B, and 100B) were tested at different temperatures using EN ISO 3675:1998 and EN ISO 3104:1996 standards. For both density and viscosity new correlations were developed and compared with published literature. A new correlation between biodiesel density and biodiesel viscosity was also developed. The second objective was achieved by using analytical models showing the effects of density and viscosity on the performance of fuel supply system. These effects were quantified over a wide range of engine operating conditions. It can be seen that the higher density and viscosity of biodiesel have a significant impact on the performance of fuel pumps and fuel filters as well as on air-fuel mixing behaviour of compression ignition (CI) engine. (author)

A study on conductivity, density, and viscosity of molten salt systems

International Nuclear Information System (INIS)

Cho, Kangjo

1976-01-01

A relation between the equivalent conductivity and density for molten salts is deduced with the aid of significant structures theory, and the solid state density at melting point is evaluated approximately for some rare-earth metal chlorides and the other chlorides. Furthermore, the relation among the equivalent conductivity, density, and viscosity for some molten salts is discussed. (auth.)

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.

Thermal ignition in a reactive variable viscosity Poiseuille flow ...

African Journals Online (AJOL)

In this paper, we investigate the thermal ignition in a strongly exothermic reaction of a variable viscosity combustible material flowing through a channel with isothermal walls under Arrhenius kinetics, neglecting the consumption of the material. Analytical solutions are constructed for the governing nonlinear boundary-value ...

Role of field-induced nanostructures, zippering and size polydispersity on effective thermal transport in magnetic fluids without significant viscosity enhancement

Science.gov (United States)

Vinod, Sithara; Philip, John

2017-12-01

Magnetic nanofluids or ferrofluids exhibit extraordinary field dependant tunable thermal conductivity (k), which make them potential candidates for microelectronic cooling applications. However, the associated viscosity enhancement under an external stimulus is undesirable for practical applications. Further, the exact mechanism of heat transport and the role of field induced nanostructures on thermal transport is not clearly understood. In this paper, through systematic thermal, rheological and microscopic studies in 'model ferrofluids', we demonstrate for the first time, the conditions to achieve very high thermal conductivity to viscosity ratio. Highly stable ferrofluids with similar crystallite size, base fluid, capping agent and magnetic properties, but with slightly different size distributions, are synthesized and characterized by X-ray diffraction, small angle X-ray scattering, transmission electron microscopy, dynamic light scattering, vibrating sample magnetometer, Fourier transform infrared spectroscopy and thermo-gravimetry. The average hydrodynamic diameters of the particles were 11.7 and 10.1 nm and the polydispersity indices (σ), were 0.226 and 0.151, respectively. We observe that the system with smaller polydispersity (σ = 0.151) gives larger k enhancement (130% for 150 G) as compared to the one with σ = 0.226 (73% for 80 G). Further, our results show that dispersions without larger aggregates and with high density interfacial capping (with surfactant) can provide very high enhancement in thermal conductivity, with insignificant viscosity enhancement, due to minimal interfacial losses. We also provide experimental evidence for the effective heat conduction (parallel mode) through a large number of space filling linear aggregates with high aspect ratio. Microscopic studies reveal that the larger particles act as nucleating sites and facilitate lateral aggregation (zippering) of linear chains that considerably reduces the number density of space

Density and viscosity behavior of a North Sea crude oil, natural gas liquid, and their mixtures

DEFF Research Database (Denmark)

Schmidt, KAG; Cisneros, Sergio; Kvamme, B

2005-01-01

to accurately model the saturation pressures, densities, and viscosities of petroleum systems ranging from natural gases to heavy crude oils. The applicability of this overall modeling technique to reproduce measured bubble points, densities, and viscosities of a North Sea crude oil, a natural gas liquid...

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.

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

International Nuclear Information System (INIS)

Stamenković, Vlada; Noack, Lena; Spohn, Tilman; Breuer, Doris

2012-01-01

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.

Skyrmions and Hall viscosity

Science.gov (United States)

Kim, Bom Soo

2018-05-01

We discuss the contribution of magnetic Skyrmions to the Hall viscosity and propose a simple way to identify it in experiments. The topological Skyrmion charge density has a distinct signature in the electric Hall conductivity that is identified in existing experimental data. In an electrically neutral system, the Skyrmion charge density is directly related to the thermal Hall conductivity. These results are direct consequences of the field theory Ward identities, which relate various physical quantities based on symmetries and have been previously applied to quantum Hall systems.

Real-time viscosity and mass density sensors requiring microliter sample volume based on nanomechanical resonators.

Science.gov (United States)

Bircher, Benjamin A; Duempelmann, Luc; Renggli, Kasper; Lang, Hans Peter; Gerber, Christoph; Bruns, Nico; Braun, Thomas

2013-09-17

A microcantilever based method for fluid viscosity and mass density measurements with high temporal resolution and microliter sample consumption is presented. Nanomechanical cantilever vibration is driven by photothermal excitation and detected by an optical beam deflection system using two laser beams of different wavelengths. The theoretical framework relating cantilever response to the viscosity and mass density of the surrounding fluid was extended to consider higher flexural modes vibrating at high Reynolds numbers. The performance of the developed sensor and extended theory was validated over a viscosity range of 1-20 mPa·s and a corresponding mass density range of 998-1176 kg/m(3) using reference fluids. Separating sample plugs from the carrier fluid by a two-phase configuration in combination with a microfluidic flow cell, allowed samples of 5 μL to be sequentially measured under continuous flow, opening the method to fast and reliable screening applications. To demonstrate the study of dynamic processes, the viscosity and mass density changes occurring during the free radical polymerization of acrylamide were monitored and compared to published data. Shear-thinning was observed in the viscosity data at higher flexural modes, which vibrate at elevated frequencies. Rheokinetic models allowed the monomer-to-polymer conversion to be tracked in spite of the shear-thinning behavior, and could be applied to study the kinetics of unknown processes.

Characterization of oscillator circuits for monitoring the density-viscosity of liquids by means of piezoelectric MEMS microresonators

Science.gov (United States)

Toledo, J.; Ruiz-Díez, V.; Pfusterschmied, G.; Schmid, U.; Sánchez-Rojas, J. L.

2017-06-01

Real-time monitoring of the physical properties of liquids, such as lubricants, is a very important issue for the automotive industry. For example, contamination of lubricating oil by diesel soot has a significant impact on engine wear. Resonant microstructures are regarded as a precise and compact solution for tracking the viscosity and density of lubricant oils. In this work, we report a piezoelectric resonator, designed to resonate with the 4th order out-of-plane modal vibration, 15-mode, and the interface circuit and calibration process for the monitoring of oil dilution with diesel fuel. In order to determine the resonance parameters of interest, i.e. resonant frequency and quality factor, an interface circuit was implemented and included within a closed-loop scheme. Two types of oscillator circuits were tested, a Phase-Locked Loop based on instrumentation, and a more compact version based on discrete electronics, showing similar resolution. Another objective of this work is the assessment of a calibration method for piezoelectric MEMS resonators in simultaneous density and viscosity sensing. An advanced calibration model, based on a Taylor series of the hydrodynamic function, was established as a suitable method for determining the density and viscosity with the lowest calibration error. Our results demonstrate the performance of the resonator in different oil samples with viscosities up to 90 mPa•s. At the highest value, the quality factor measured at 25°C was around 22. The best resolution obtained was 2.4•10-6 g/ml for the density and 2.7•10-3 mPa•s for the viscosity, in pure lubricant oil SAE 0W30 at 90°C. Furthermore, the estimated density and viscosity values with the MEMS resonator were compared to those obtained with a commercial density-viscosity meter, reaching a mean calibration error in the best scenario of around 0.08% for the density and 3.8% for the viscosity.

Density, electrical conductivity, viscosity and excess properties of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide + propylene carbonate binary mixtures

International Nuclear Information System (INIS)

Vraneš, Milan; Zec, Nebojša; Tot, Aleksandar; Papović, Snežana; Dožić, Sanja; Gadžurić, Slobodan

2014-01-01

Highlights: • Densities of [bmim][NTf 2 ] mixtures with propylene carbonate were measured. • Excess properties were calculated. • Formation of hydrogen bonds between IL and PC was discussed. • Electrical conductivity and viscosity were also measured. • Influence of temperature and composition on mixture properties were studied. -- Abstract: Densities of binary liquid mixtures of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [bmim][NTf 2 ], with propylene carbonate (PC) were measured at temperatures from (293.15 to 323.15) K and at atmospheric pressure over the whole composition range. The electrical conductivity was measured in the range from (293.15 to 328.15) K. Also, viscosity of [bmim][NTf 2 ] + PC binary mixtures was measured from (298.15 to 333.15) K. Excess molar volumes, V E , have been obtained from the experimental densities and were fitted to Redlich–Kister polynomial equation. Other volumetric properties, such as isobaric thermal expansion coefficients, partial molar volumes, apparent molar volumes and partial molar volumes at infinite dilution have been also calculated, in order to obtain information about interactions between PC and selected ionic liquid. Results are discussed in order to understand the hydrogen bonds formation between components of the mixture

On the density and viscosity of (water + dimethylsulphoxide) binary mixtures

International Nuclear Information System (INIS)

Carmen Grande, Maria del; Julia, Jorge Alvarez; Garcia, Mariano; Marschoff, Carlos M.

2007-01-01

Density and viscosity of (water + dimethylsulphoxide) were measured precisely over the whole composition range at T = (298.15, 303.15, 308.15, 313.15, and 318.15) K. Differences between values from different authors are clarified and more reliable partial molar volumes are obtained

Solubility of carbon dioxide, methane, and ethane in 1-butanol and saturated liquid densities and viscosities

International Nuclear Information System (INIS)

Kariznovi, Mohammad; Nourozieh, Hossein; Abedi, Jalal

2013-01-01

Highlights: • Experimental solubilities of CH 4 , C 2 H 6 , and CO 2 in 1-butanol and saturated liquid properties. • Solubilities and saturated liquid densities were predicted with SRK and PR EOS. • Solubility of C 2 H 6 in 1-butanol is higher than CH 4 and CO 2 . • Liquid density and viscosity reduces with dissolution of CH 4 and C 2 H 6 . • Dissolution of CO 2 increases liquid density and reduces liquid viscosity. -- Abstract: A designed pressure–volume–temperature (PVT) apparatus has been used to measure the (vapor + liquid) equilibrium properties of three binary mixtures (methane +, ethane +, and carbon dioxide + 1-butanol) at two temperatures (303 and 323) K and at the pressures up to 6 MPa. The solubility of the compressed gases in 1-butanol and the saturated liquid densities and viscosities were measured. In addition, the density and viscosity of pure 1-butanol were measured at two temperatures (303 and 323) K and at the pressures up to 10 MPa. The experimental results show that the solubility of the gases in 1-butanol increases with pressure and decreases with temperature. The dissolution of gases in 1-butanol causes a decline in the viscosity of liquid phase. The saturated liquid density follows a decreasing trend with the solubility of methane and ethane. However, the dissolution of carbon dioxide in 1-butanol leads to an increase in the density of liquid phase. The experimental data are well correlated with Soave–Redlich–Kwong (SRK) and Peng–Robinson (PR) equations of state (EOSs). SRK EOS was slightly superior for correlating the saturated liquid densities

Resolution in QCM sensors for the viscosity and density of liquids: application to lead acid batteries.

Science.gov (United States)

Cao-Paz, Ana María; Rodríguez-Pardo, Loreto; Fariña, José; Marcos-Acevedo, Jorge

2012-01-01

In battery applications, particularly in automobiles, submarines and remote communications, the state of charge (SoC) is needed in order to manage batteries efficiently. The most widely used physical parameter for this is electrolyte density. However, there is greater dependency between electrolyte viscosity and SoC than that seen for density and SoC. This paper presents a Quartz Crystal Microbalance (QCM) sensor for electrolyte density-viscosity product measurements in lead acid batteries. The sensor is calibrated in H(2)SO(4) solutions in the battery electrolyte range to obtain sensitivity, noise and resolution. Also, real-time tests of charge and discharge are conducted placing the quartz crystal inside the battery. At the same time, the present theoretical "resolution limit" to measure the square root of the density-viscosity product [Formula: see text] of a liquid medium or best resolution achievable with a QCM oscillator is determined. Findings show that the resolution limit only depends on the characteristics of the liquid to be studied and not on frequency. The QCM resolution limit for [Formula: see text] measurements worsens when the density-viscosity product of the liquid is increased, but it cannot be improved by elevating the work frequency.

Densities and viscosities of the mixtures (formamide + 2-alkanol): Experimental and theoretical approaches

International Nuclear Information System (INIS)

Almasi, Mohammad

2014-01-01

Graphical abstract: Viscosity deviations △η vs. mole fraction of FA, for binary mixtures of FA with (□) 2-PrOH, (●) 2-BuOH, (■) 2-PenOH, (◀) 2-HexOH, (◊) 2-HepOH at T = 298.15 K. The solid curves were calculated from Redlich–Kister type equation. -- Highlights: • Densities and viscosities of the mixtures (formamide + 2-alkanols) were measured. • Experiments were performed over the entire mole fraction at four temperatures. • SAFT and PC-SAFT were applied to predict the volumetric behavior of mixtures. • PRSV equation of state (EOS) has been used to predict the binary viscosities. -- Abstract: Densities and viscosities of binary liquid mixtures of formamide (FA) with polar solvents namely, 2-PrOH, 2-BuOH, 2-PenOH, 2-HexOH, and 2-HepOH, have been measured as a function of composition range at temperatures (298.15, 303.15, 308.15, 313.15) K and ambient pressure. From experimental data, excess molar volumes, V m E and viscosity deviations Δη, were calculated and correlated by Redlich–Kister type function. The effect of temperature and chain-length of the 2-alkanols on the excess molar volumes and viscosity deviations are discussed in terms of molecular interaction between unlike molecules. The statistical associating fluid theory (SAFT), and perturbed chain statistical associating fluid theory (PC-SAFT) were applied to correlate and predict the volumetric behavior of the mixtures. The best predictions were achieved with the PC-SAFT equation of state. Also the Peng–Robinson–Stryjek–Vera equation of state has been used to predict the viscosity of binary mixtures

Resolution in QCM Sensors for the Viscosity and Density of Liquids: Application to Lead Acid Batteries

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Jorge Marcos-Acevedo

2012-08-01

Full Text Available In battery applications, particularly in automobiles, submarines and remote communications, the state of charge (SoC is needed in order to manage batteries efficiently. The most widely used physical parameter for this is electrolyte density. However, there is greater dependency between electrolyte viscosity and SoC than that seen for density and SoC. This paper presents a Quartz Crystal Microbalance (QCM sensor for electrolyte density-viscosity product measurements in lead acid batteries. The sensor is calibrated in H₂SO₄ solutions in the battery electrolyte range to obtain sensitivity, noise and resolution. Also, real-time tests of charge and discharge are conducted placing the quartz crystal inside the battery. At the same time, the present theoretical “resolution limit” to measure the square root of the density-viscosity product ( of a liquid medium or best resolution achievable with a QCM oscillator is determined. Findings show that the resolution limit only depends on the characteristics of the liquid to be studied and not on frequency. The QCM resolution limit for  measurements worsens when the density-viscosity product of the liquid is increased, but it cannot be improved by elevating the work frequency.

Thermophysical Properties of Liquid Te: Density, Electrical Conductivity, and Viscosity

Science.gov (United States)

Li, C.; Su, C.; Lehoczky, S. L.; Scripa, R. N.; Ban, H.; Lin, B.

2004-01-01

The thermophysical properties of liquid Te, namely, density, electrical conductivity, and viscosity, were determined using the pycnometric and transient torque methods from the melting point of Te (723 K) to approximately 1150 K. A maximum was observed in the density of liquid Te as the temperature was increased. The electrical conductivity of liquid Te increased to a constant value of 2.89 x 10(exp 5 OMEGA-1m-1) as the temperature was raised above 1000 K. The viscosity decreased rapidly upon heating the liquid to elevated temperatures. The anomalous behaviors of the measured properties are explained as caused by the structural transitions in the liquid and discussed in terms of Eyring's and Bachiskii's predicted behaviors for homogeneous liquids. The Properties were also measured as a function of time after the liquid was coded from approximately 1173 or 1123 to 823 K. No relaxation phenomena were observed in the properties after the temperature of liquid Te was decreased to 823 K, in contrast to the relaxation behavior observed for some of the Te compounds.

Slabs and plumes crossing a broad density/viscosity discontinuity in the mid lower mantle (Invited)

Science.gov (United States)

Morra, G.; Yuen, D. A.; Cammarano, F.

2010-12-01

The depth-dependence of the viscosity is not well constrained by observations alone. Non-monotonic viscosity profiles have been often proposed in the past and are in the range of possible solutions. Such viscosity structures find new vigor on the light of recent discoveries of iron-spin transition in mantle minerals and their consequences on seismic interpretation [1] and dynamical evolution of the mantle. Using the recently introduced Multipole-Accelerated Boundary Element Method, we study the entire space of possible models of plumes and slabs crossing a broad region where mantle viscosity and/or density are non-monotonic [2]. The viscosity peak considered are 1, to 100 times then the rest of the mantle, while the density step considered is 0 to 2% different from the adiabatic profile. We identify the critical viscosity and density profiles that produce stalling or penetration of slabs and the continuous or intermittent penetration of plumes through the mid lower mantle. Based on our results, we envisage possible dynamic scenarios that would separate the mantle in two regions,suggesting a long term bifurcation originating, probably, from the spin transition itself. References: [1] Cammarano, F.; Marquardt, H.; Speziale, S.; Tackley, P. J., 2010, Role of iron-spin transition in ferropericlase on seismic interpretation: A broad thermochemical transition in the mid mantle? Geophysical Research Letters, Volume 37, Issue 3, CiteID L03308 [2] G. Morra, D. A. Yuen, L. Boschi, P. Chatelain, P. Koumoutzakos and P. Tackley, 2010, The fate of the slabs interacting with a smooth viscosity discontinuity in the mid lower mantle, Physics of the Earth and Planetary Interiors, Volume 180, Issues 3-4, 271-282, doi:10.1016/j.pepi.2010.04.001

Density, viscosity and surface tension of liquid phase Beckmann rearrangement mixtures

NARCIS (Netherlands)

Zuidhof, K.T.; Croon, de M.H.J.M.; Schouten, J.C.; Tinge, J.T.

2015-01-01

We have determined the density, dynamic viscosity, and surface tension of liquid phase Beckmann rearrangement mixtures, consisting of e-caprolactam and fuming oleum. These important properties have been measured in wide ranges of both temperature and molar ratios of acid and e-caprolactam, covering

The effect of compressive viscosity and thermal conduction on the longitudinal MHD waves

Science.gov (United States)

Bahari, K.; Shahhosaini, N.

2018-05-01

longitudinal Magnetohydrodynamic (MHD) oscillations have been studied in a slowly cooling coronal loop, in the presence of thermal conduction and compressive viscosity, in the linear MHD approximation. WKB method has been used to solve the governing equations. In the leading order approximation the dispersion relation has been obtained, and using the first order approximation the time dependent amplitude has been determined. Cooling causes the oscillations to amplify and damping mechanisms are more efficient in hot loops. In cool loops the oscillation amplitude increases with time but in hot loops the oscillation amplitude decreases with time. Our conclusion is that in hot loops the efficiency of the compressive viscosity in damping longitudinal waves is comparable to that of the thermal conduction.

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

International Nuclear Information System (INIS)

Li, Lihua; Zhang, Jianbin; Li, Qiang; Guo, Bo; Zhao, Tianxiang; Sha, Feng

2014-01-01

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

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.

Density, viscosity and electrical conductivity of protic alkanolammonium ionic liquids.

Science.gov (United States)

Pinkert, André; Ang, Keng L; Marsh, Kenneth N; Pang, Shusheng

2011-03-21

Ionic liquids are molten salts with melting temperatures below the boiling point of water, and their qualification for applications in potential industrial processes does depend on their fundamental physical properties such as density, viscosity and electrical conductivity. This study aims to investigate the structure-property relationship of 15 ILs that are primarily composed of alkanolammonium cations and organic acid anions. The influence of both the nature and number of alkanol substituents on the cation and the nature of the anion on the densities, viscosities and electrical conductivities at ambient and elevated temperatures are discussed. Walden rule plots are used to estimate the ionic nature of these ionic liquids, and comparison with other studies reveals that most of the investigated ionic liquids show Walden rule values similar to many non-protic ionic liquids containing imidazolium, pyrrolidinium, tetraalkylammonium, or tetraalkylphosphonium cations. Comparison of literature data reveals major disagreements in the reported properties for the investigated ionic liquids. A detailed analysis of the reported experimental procedures suggests that inappropriate drying methods can account for some of the discrepancies. Furthermore, an example for the improved presentation of experimental data in scientific literature is presented.

Experimental and modeling investigations of solubility and saturated liquid densities and viscosities for binary systems (methane +, ethane +, and carbon dioxide + 2-propanol)

International Nuclear Information System (INIS)

Nourozieh, Hossein; Kariznovi, Mohammad; Abedi, Jalal

2013-01-01

Highlights: • Solubilities of CH 4 , C 2 H 6 , and CO 2 in 2-propanol and saturated density and viscosity. • Solubility of C 2 H 6 in 2-propanol is higher than CH 4 and CO 2 . • Dissolution of CO 2 increases liquid density and reduces liquid viscosity. • Liquid density and viscosity reduces with dissolution of CH 4 and C 2 H 6 . • Solubilities and saturated liquid densities were predicted with SRK and PR EOS. -- Abstract: Solubilities of methane, ethane, and carbon dioxide in 2-propanol have been measured at the temperatures (303 and 323) K and at the pressures up to 6 MPa using an in-house designed PVT apparatus. The saturated liquid properties, density and viscosity, were also measured in each experiment. Prior to the phase equilibrium measurements, the density and viscosity of pure 2-propanol were measured at the temperatures (303 and 323) K over the pressure range (0.1 to 10) MPa. The dissolution of carbon dioxide in 2-propanol caused a decline in the viscosity of saturated liquid phase while an increase in the density of gas-expanded liquid was observed. The viscosity-pressure trends for methane- and ethane-saturated liquid viscosities were similar to carbon dioxide, but the saturated liquid densities decreased with the dissolution of methane and ethane in 2-propanol. Solubility increased with pressure and decreased with temperature for all compressed gases (methane, ethane and carbon dioxide). The experimental data were well correlated using Soave–Redlich–Kwong and Peng–Robinson equations of state. The solubilities and saturated liquid densities were well represented with both equations of state, and there is no superior equation of state for the modeling of the phase compositions and saturated liquid densities

Densities, viscosities, and isobaric heat capacities of the system (1-butanol + cyclohexane) at high pressures

International Nuclear Information System (INIS)

Torín-Ollarves, Geraldine A.; Martín, M. Carmen; Chamorro, César R.; Segovia, José J.

2014-01-01

Highlights: • The densities of cyclohexane and its mixtures with 1-butanol were measured. • The excess molar volumes were calculated and correlated. • The viscosities were measured at atmospheric pressure. • The isobaric heat capacities were measured at p = (0.1 to 25) MPa at T = (293.15 and 313.15) K. • A positive deviation from the ideal behavior is observed. - Abstract: The cyclohexane and the system of 1-butanol + cyclohexane have been characterized using densities, viscosities and isobaric heat capacities measurements. For that, the densities were measured in a high-pressure vibrating tube densimeter at five temperatures from (293.15 to 333.15) K and pressures up to 100 MPa. The measurements were correlated with the empirical Tamman–Tait equation. Moreover, the isobaric heat capacities of the binary system were measured in a high-pressure automated flow calorimeter at T = (293.15 and 313.15) K and pressures up to 25 MPa for pure cyclohexane and in admixture with 1-butanol. The excess molar heat capacities were assessed for the mixture and a positive deviation from the ideality was obtained, except for a small part in the region rich in alkanol. The viscosity measurements were carried out, at the calorimeter conditions, for correcting the experimental values of isobaric heat capacities due to friction along the tube. The viscosity was measured at atmospheric pressure in a Stabinger Anton Paar SVM 3000 viscometer in the temperature range of (293.15 to 333.15) K for cyclohexane and the mixtures. At high pressure, the viscosities were estimated using Lucas method

Density and viscosity of aqueous solutions of N,N-dimethylethanolamine at p = 0.1 MPa from T = (293.15 to 363.15) K

Energy Technology Data Exchange (ETDEWEB)

Bernal-Garcia, J. Manuel [Instituto Mexicano del Petroleo, Mexico D.F. C.P. 07330 (Mexico); Hall, Kenneth R. [Chemical Engineering Department, Texas A and M University, College Station, TX 77843 (United States); Estrada-Baltazar, Alejandro [Departamento de Ingenieria Quimica, Instituto Tecnologico de Celaya, Celaya, Guanajuato, CP 38010 (Mexico); Iglesias-Silva, Gustavo A. [Departamento de Ingenieria Quimica, Instituto Tecnologico de Celaya, Celaya, Guanajuato, CP 38010 (Mexico)]. E-mail: gais@iqcelaya.itc.mx

2005-08-15

This work presents atmospheric density and viscosity values for (N,N-dimethylethanolamine + water) over the entire composition range from T (293.15 to 363.15) K for density and from T = (313.15 to 353.15) K for viscosity. Density measurements come from a vibrating tube densimeter while we have used three different Cannon-Fenske viscosimeters for the viscosity measurements. Excess molar volumes and viscosity deviations are calculated using a Redlich-Kister type equation. Excess molar volumes present negative deviations from ideality and viscosity deviations are positive at all temperatures and compositions in this work.

Density and viscosity of aqueous solutions of N,N-dimethylethanolamine at p = 0.1 MPa from T = (293.15 to 363.15) K

International Nuclear Information System (INIS)

Bernal-Garcia, J. Manuel; Hall, Kenneth R.; Estrada-Baltazar, Alejandro; Iglesias-Silva, Gustavo A.

2005-01-01

This work presents atmospheric density and viscosity values for (N,N-dimethylethanolamine + water) over the entire composition range from T (293.15 to 363.15) K for density and from T = (313.15 to 353.15) K for viscosity. Density measurements come from a vibrating tube densimeter while we have used three different Cannon-Fenske viscosimeters for the viscosity measurements. Excess molar volumes and viscosity deviations are calculated using a Redlich-Kister type equation. Excess molar volumes present negative deviations from ideality and viscosity deviations are positive at all temperatures and compositions in this work

Viscosity and density study for characterization of oil mixtures; Estudo da viscosidade e densidade para caracterizacao das misturas de petroleo

Energy Technology Data Exchange (ETDEWEB)

Santos, Michelle I.; Azevedo, Vildomar S.; Jacinto, Tulio Wagner B. [Aurizonia Petroleo S.A, Natal, RN (Brazil); Vieira, Mariane; Vidal, Rosangela Regia Lima; Garcia, Rosangela Balaban [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

2008-07-01

The oil can be defined as a mixture of hydrocarbons and sulphur, nitrogen and oxygenated organic derivatives at lower amount. There is a practical difficulty of analytical determination of the oil composition, mainly due to the large quantity of medium and heavy oil fractions. For heavier fractions, it is necessary to infer the composition of the cut from properties that can be readily obtained in the laboratory, such as refraction index, density and viscosity. The analysis of oil composition and its fractions is important information on various aspects (IOB et al., 1996): determining the operating conditions of refining, selection of suitable catalysts and mixing operations ('blending'), the economic evaluation of mixtures and analysis of environmental impact due to emissions. The first study on characterization of fractions of the oil was reported by Hill and Coats (1928), who set an empirical relationship between the density and Saybolt viscosity named viscosity-density constant (VGC). The statement was obtained from the analysis of the density with the oil viscosity changes. Physical properties such as density, boiling point and viscosity can be used to classify the oil. The aim of this work was to classify oil fractions based on viscosity-density constant, using mixtures of oils with different APIs. The results showed that there is an optimum composition for each mixture, and the addition of more oil of medium classification does not lead to potential commercial oil. (author)

Determination of Fluid Density and Viscosity by Analyzing Flexural Wave Propagations on the Vibrating Micro-Cantilever

Directory of Open Access Journals (Sweden)

Deokman Kim

2017-10-01

Full Text Available The determination of fluid density and viscosity using most cantilever-based sensors is based on changes in resonant frequency and peak width. Here, we present a wave propagation analysis using piezoelectrically excited micro-cantilevers under distributed fluid loading. The standing wave shapes of microscale-thickness cantilevers partially immersed in liquids (water, 25% glycerol, and acetone, and nanoscale-thickness microfabricated cantilevers fully immersed in gases (air at three different pressures, carbon dioxide, and nitrogen were investigated to identify the effects of fluid-structure interactions to thus determine the fluid properties. This measurement method was validated by comparing with the known fluid properties, which agreed well with the measurements. The relative differences for the liquids were less than 4.8% for the densities and 3.1% for the viscosities, and those for the gases were less than 6.7% for the densities and 7.3% for the viscosities, showing better agreements in liquids than in gases.

Thermal conductivity and viscosity of Al2O3 nanofluid based on car engine coolant

International Nuclear Information System (INIS)

Kole, Madhusree; Dey, T K

2010-01-01

Various suspensions containing Al 2 O 3 nanoparticles ( 2 O 3 nanoparticles as well as temperature between 10 and 80 0 C. The prepared nanofluid, containing only 0.035 volume fraction of Al 2 O 3 nanoparticles, displays a fairly higher thermal conductivity than the base fluid and a maximum enhancement (k nf /k bf ) of ∼10.41% is observed at room temperature. The thermal conductivity enhancement of the Al 2 O 3 nanofluid based on engine coolant is proportional to the volume fraction of Al 2 O 3 . The volume fraction and temperature dependence of the thermal conductivity of the studied nanofluids present excellent correspondence with the model proposed by Prasher et al (2005 Phys. Rev. Lett. 94 025901), which takes into account the role of translational Brownian motion, interparticle potential and convection in fluid arising from Brownian movement of nanoparticles for thermal energy transfer in nanofluids. Viscosity data demonstrate transition from Newtonian characteristics for the base fluid to non-Newtonian behaviour with increasing content of Al 2 O 3 in the base fluid (coolant). The data also show that the viscosity increases with an increase in concentration and decreases with an increase in temperature. An empirical correlation of the type log(μ nf ) = A exp(-BT) explains the observed temperature dependence of the measured viscosity of Al 2 O 3 nanofluid based on car engine coolant. We further confirm that Al 2 O 3 nanoparticle concentration dependence of the viscosity of nanofluids is very well predicted on the basis of a recently reported theoretical model (Masoumi et al 2009 J. Phys. D: Appl. Phys. 42 055501), which considers Brownian motion of nanoparticles in the nanofluid.

Thermal conductivity and viscosity of hybrid nanfluids prepared with magnetic nanodiamond-cobalt oxide (ND-Co3O4 nanocomposite

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L. Syam Sundar

2016-03-01

Full Text Available Synthesis of magnetic nanodiamond-cobalt oxide (ND-Co3O4 nanocomposite material; preparation of nanofluids and estimation of thermal properties such as thermal conductivity and viscosity has been explained experimentally in this paper. The nanocomposite material has been synthesized by using in-situ growth technique and chemical coprecipitation between cobalt chloride and sodium borohydrate. The various techniques such as XRD, TEM, XPS and VSM have been used to confirm the ND and Co3O4 phase of synthesized nanocomposite. The hybrid nanofluids have been prepared by dispersing synthesized ND-Co3O4 nanocomposite in water, ethylene glycol/water mixtures. The thermal properties such as thermal conductivity and viscosity have been measured experimentally at different weight concentrations and temperatures. The results reveal that the thermal conductivity enhancements are about 16%, 9%, 14%, 11% and 10% for water, EG, 20:80%, 40:60%, and 60:40% EG/W based nanofluids at 0.15 wt% concentrations and at 60 °C respectively. Similarly the viscosity enhancements are about 1.45-times, 1.46-times, 1.15-times, 1.19-times, and 1.51-times for water, EG, 20:80%, 40:60%, and 60:40% EG/W based nanofluids at 0.15 wt% concentrations and at 60 °C respectively. Based on the experimental data new correlations for thermal conductivity and viscosity have been developed.

Enhanced Thermal Conductivity and Viscosity of Nanodiamond-Nickel Nanocomposite Nanofluids

Science.gov (United States)

Sundar, L. Syam; Singh, Manoj K.; Ramana, E. Venkata; Singh, Budhendra; Grácio, José; Sousa, Antonio C. M.

2014-01-01

We report a new type of magnetic nanofluids, which is based on a hybrid composite of nanodiamond and nickel (ND-Ni) nanoparticles. We prepared the nanoparticles by an in-situ method involving the dispersion of caboxylated nanodiamond (c-ND) nanoparticles in ethylene glycol (EG) followed by mixing of nickel chloride and, at the reaction temperature of 140°C, the use of sodium borohydrate as the reducing agent to form the ND-Ni nanoparticles. We performed their detailed surface and magnetic characterization by X-ray diffraction, micro-Raman, high-resolution transmission electron microscopy, and vibrating sample magnetometer. We prepared stable magnetic nanofluids by dispersing ND-Ni nanoparticles in a mixture of water and EG; we conducted measurements to determine the thermal conductivity and viscosity of the nanofluid with different nanoparticles loadings. The nanofluid for a 3.03% wt. of ND-Ni nanoparticles dispersed in water and EG exhibits a maximum thermal conductivity enhancement of 21% and 13%, respectively. For the same particle loading of 3.03% wt., the viscosity enhancement is 2-fold and 1.5-fold for water and EG nanofluids. This particular magnetic nanofluid, beyond its obvious usage in heat transfer equipment, may find potential applications in such diverse fields as optics and magnetic resonance imaging. PMID:24509508

In situ evaluation of density, viscosity, and thickness of adsorbed soft layers by combined surface acoustic wave and surface plasmon resonance.

Science.gov (United States)

Francis, Laurent A; Friedt, Jean-Michel; Zhou, Cheng; Bertrand, Patrick

2006-06-15

We show the theoretical and experimental combination of acoustic and optical methods for the in situ quantitative evaluation of the density, the viscosity, and the thickness of soft layers adsorbed on chemically tailored metal surfaces. For the highest sensitivity and an operation in liquids, a Love mode surface acoustic wave (SAW) sensor with a hydrophobized gold-coated sensing area is the acoustic method, while surface plasmon resonance (SPR) on the same gold surface as the optical method is monitored simultaneously in a single setup for the real-time and label-free measurement of the parameters of adsorbed soft layers, which means for layers with a predominant viscous behavior. A general mathematical modeling in equivalent viscoelastic transmission lines is presented to determine the correlation between experimental SAW signal shifts and the waveguide structure including the presence of the adsorbed layer and the supporting liquid from which it segregates. A methodology is presented to identify from SAW and SPR simulations the parameters representatives of the soft layer. During the absorption of a soft layer, thickness or viscosity changes are observed in the experimental ratio of the SAW signal attenuation to the SAW signal phase and are correlated with the theoretical model. As application example, the simulation method is applied to study the thermal behavior of physisorbed PNIPAAm, a polymer whose conformation is sensitive to temperature, under a cycling variation of temperature between 20 and 40 degrees C. Under the assumption of the bulk density and the bulk refractive index of PNIPAAm, thickness and viscosity of the film are obtained from simulations; the viscosity is correlated to the solvent content of the physisorbed layer.

Effect of injection angle, density ratio, and viscosity on droplet formation in a microfluidic T-junction

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Mohammad Yaghoub Abdollahzadeh Jamalabadi

2017-07-01

Full Text Available The T-junction microchannel device makes available a sharp edge to form micro-droplets from bio-material solutions. This article investigates the effects of injection angle, flow rate ratio, density ratio, viscosity ratio, contact angle, and slip length in the process of formation of uniform droplets in microfluidic T-junctions. The governing equations were solved by the commercial software. The results show that contact angle, slip length, and injection angles near the perpendicular and parallel conditions have an increasing effect on the diameter of generated droplets, while flow rate, density and viscosity ratios, and other injection angles had a decreasing effect on the diameter. Keywords: Microfluidics, Droplet formation, Flow rate ratio, Density ratio

Separate measurement of the density and viscosity of a liquid using a quartz crystal microbalance based on admittance analysis (QCM-A)

International Nuclear Information System (INIS)

Itoh, Atsushi; Ichihashi, Motoko

2011-01-01

We previously used a quartz crystal microbalance (QCM) to identify a frequency f 2 that allows measurement of the mass load without being affected by the viscous load of a liquid in the liquid phase. Here, we determined that frequency in order to separately measure the density and viscosity of a Newtonian liquid. Martin et al separately measured the density and viscosity of a liquid by immersing two quartz resonators, i.e. a smooth-surface resonator and a textured-surface resonator, in the liquid. We used a QCM based on admittance analysis (QCM-A) in the current study to separately measure the viscosity and density of a liquid using only a textured-surface resonator. In the current experiments, we measured the density and viscosity of 500 µl of 10%, 30%, and 50% aqueous glycerol solutions and compared the measured values to reference values. The density obtained had an error of ±1.5% of reference values and the viscosity had an error of about ±5% of reference values. Similar results were obtained with 500 µl of 10%, 30%, and 50% ethanol solutions. Measurement was possible with a quartz resonator, so measurements were made with even smaller samples. The density and viscosity of a liquid were successfully determined with an extremely small amount of liquid, i.e. 10 µl, with almost the same precision as when using 500 µl of the liquid

Experimental study of the density and viscosity of 1-ethyl-3-methylimidazolium ethyl sulfate

International Nuclear Information System (INIS)

Schmidt, H.; Stephan, M.; Safarov, J.; Kul, I.; Nocke, J.; Abdulagatov, I.M.; Hassel, E.

2012-01-01

Highlights: ► Density of the ionic liquid [EMIM][EtSO 4 ]. ► Viscosity of the ionic liquid [EMIM][EtSO 4 ]. ► Thermodynamic properties of ionic liquid [EMIM][EtSO 4 ]. ► Equation of state of ionic liquid [EMIM][EtSO 4 ]. - Abstract: Density and viscosity of 1-ethyl-3-methylimidazolium ethyl sulfate [EMIM][EtSO 4 ] have been measured over the temperature range from (283.15 to 413.15) K and at pressures up to 140 MPa and in the temperature range from (283.15 to 373.15) K at 0.1 MPa, respectively. The expanded uncertainty of the density, pressure, temperature, and viscosity measurements at the 95% confidence level with a coverage factor of k = 2 is estimated to be (0.01 to 0.08)%, 0.1%, 15 mK, and 0.35%, respectively. The measurements were carried out with an Anton–Paar DMA HPM vibration-tube densimeter and a fully automated SVM 3000 Anton–Paar rotational Stabinger viscometer. The vibration-tube densimeter was calibrated using various reference fluids, double-distilled water, methanol, toluene, and aqueous NaCl solutions. An empiric equation of state for [EMIM][EtSO 4 ] has been developed using the measured (p, ρ, T) data. This equation was used to calculate the various thermodynamic properties of the IL and for compare with measured properties (speed of sound and enthalpy). Theoretically based Arrhenius–Andrade and Vogel–Tamman–Fulcher type equations were use to describe of the temperature dependence of measured viscosities for [EMIM][EtSO 4 ]. All measured properties were detailed compared with the reported data by other author.

Vapour pressures, densities, and viscosities of the (water + lithium bromide + potassium acetate) system and (water + lithium bromide + sodium lactate) system

International Nuclear Information System (INIS)

Lucas, Antonio de; Donate, Marina; Rodriguez, Juan F.

2006-01-01

Measurements of thermophysical properties (vapour pressure, density, and viscosity) of the (water + lithium bromide + potassium acetate) system LiBr:CH 3 COOK = 2:1 by mass ratio and the (water + lithium bromide + sodium lactate) system LiBr:CH 3 CH(OH)COONa = 2:1 by mass ratio were measured. The system, a possible new working fluid for absorption heat pump, consists of absorbent (LiBr + CH 3 COOK) or (LiBr + CH 3 CH(OH)COONa) and refrigerant H 2 O. The vapour pressures were measured in the ranges of temperature and absorbent concentration from T = (293.15 to 333.15) K and from mass fraction 0.20 to 0.50, densities and viscosities were measured from T = (293.15 to 323.15) K and from mass fraction 0.20 to 0.40. The experimental data were correlated with an Antoine-type equation. Densities and viscosities were measured in the same range of temperature and absorbent concentration as that of the vapour pressure. Regression equations for densities and viscosities were obtained with a minimum mean square error criterion

Densities and viscosities for binary mixtures of n-heptane with alcohols at different temperatures

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Budeanu Maria Magdalena

2017-01-01

Full Text Available Densities (ρ and viscosities (η of the binary systems n-heptane with alcohols (ethanol, propan-1-ol and propan-2-ol were measured at temperatures between 288.15 and 308.15 K and at atmospheric pressure, over the whole composition range. The excess values of molar volume (VE and viscosity (ηE were calculated from experimental measurements. The excess functions of the binary systems were fitted to Redlich–Kister Equation. Comparison between experimental excess molar volume and the one calculated from Flory and Prigogine–Flory–Patterson theories, has also been done. The viscosity results were fitted to the equations of Grunberg–Nissan, Heric–Brewer, Jouyban–Acree and McAllister. Also, the activation energies of viscous flow have been obtained and their variations with compositions have been discussed.

Experimental study of the density and viscosity of polyethylene glycols and their mixtures at temperatures from 293 K to 473 K and at atmospheric pressure

International Nuclear Information System (INIS)

Sagdeev, D.I.; Fomina, M.G.; Mukhamedzyanov, G.Kh.; Abdulagatov, I.M.

2011-01-01

Highlights: → Viscosity and density of polyethylene glycols. → Combined experimental apparatus for density and viscosity measurements. → Vogel-Tamman-Fulcher model for viscosity. - Abstract: A new apparatus to measure simultaneously the density and viscosity of liquids has been designed and constructed based on the hydrostatic weighing and falling-body principles. The density and viscosity of monoethylene glycol (MEG), diethylene glycol (DEG), and triethylene glycol (TEG) and their binary, (50%MEG + 50%DEG), (50%MEG + 50%TEG), (50%DEG + 50%TEG), and ternary (33.33%MEG + 33.33%DEG + 33.34%TEG) mixtures have been measured over the temperature range from 293 K to 473 K and at atmospheric pressure. The expanded uncertainty of the density, pressure, temperature, and viscosity measurements at the 95% confidence level with a coverage factor of k = 2 is estimated to be 0.15% to 0.30%, 0.05%, 0.06 K, and 1.5% to 2.0% (depending on temperature and pressure ranges), respectively. The theoretically based Arrhenius-Andrade and Vogel-Tamman-Fulcher type equations were used to describe the temperature dependence of measured viscosities for pure polyethylene glycols and their mixtures.

Improvements in gastric diagnosis by using high density contrast media with low viscosity

International Nuclear Information System (INIS)

Toischer, H.P.

1983-01-01

In a retrospective clinical study, 150 unselected double contrast examinations of the stomach using conventional contrast media (100 g/100 ml barium sulphate) were compared with a similar number of examinations using a high density contrast medium of flow viscosity (250 g/100 ml barium sulphate). The high density contrast medium was distinctly better for demonstrating detail of the gastric mucosa. The uneveness of coating and instability of the older high density contrast media was observed in 15.5% of cases and, in no instance, did this make it impossible to reach a diagnosis. (orig.) [de

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.

Experimental density, viscosity, interfacial tension and water solubility of ethyl benzene-α-methyl benzyl alcohol–water system

International Nuclear Information System (INIS)

Barega, Esayas W.; Zondervan, Edwin; Haan, André B. de

2013-01-01

Highlights: • Properties were measured for MBA (methyl benzyl alcohol)-EB (ethyl benzene)-water. • MBA concentration was found to influence all the properties strongly. • The water solubility, density, and viscosity increased at high MBA concentration. • The interfacial tension decreased sharply at high MBA concentration. • MBA dictates the phase separation and mass transfer of the ternary system. -- Abstract: Density, viscosity, interfacial tension, and water solubility were measured for the (α-methyl benzyl alcohol (MBA) + Ethyl benzene (EB)) system at different concentrations of MBA in contact with water and sodium hydroxide solution (0.01 mol · kg −1 ) as aqueous phases. The properties were measured to identify the component which plays a governing role in changing the physical properties relevant to mass transfer and phase separation of the ternary system. The concentration of MBA was found to be the major factor influencing all the properties. The water solubility, the density, and the viscosity increased notably at higher concentrations of MBA; while, the interfacial tension decreased strongly. The use of 0.01 mol · kg −1 NaOH as an aqueous phase resulted in a decrease of the interfacial tension and a minor decrease in the water solubility. The density data were correlated using a quadratic mixing rule to describe the influence of concentration at any temperature. The viscosity data are correlated using the Nissan and Grunberg and Katti-Chaudhri equations. The Szyzkowski’s equation was used to correlate the interfacial tension data. The water solubility data were described using an exponential relationship. All the correlations described the experimental physical property data adequately

Effect of temperature dependent properties on MHD convection of water near its density maximum in a square cavity

International Nuclear Information System (INIS)

Sivasankaran, S.; Hoa, C.J.

2008-01-01

Natural convection of water near its density maximum in the presence of magnetic field in a cavity with temperature dependent properties is studied numerically. The viscosity and thermal conductivity of the water is varied with reference temperature and calculated by cubic polynomial. The finite volume method is used to solve the governing equations. The results are presented graphically in the form of streamlines, isotherms and velocity vectors and are discussed for various combinations of reference temperature parameter, Rayleigh number, density inversion parameter and Hartmann number. It is observed that flow and temperature field are affected significantly by changing the reference temperature parameter for temperature dependent thermal conductivity and both temperature dependent viscosity and thermal conductivity cases. There is no significant effect on fluid flow and temperature distributions for temperature dependent viscosity case when changing the values of reference temperature parameter. The average heat transfer rate considering temperature-dependent viscosity are higher than considering temperature-dependent thermal conductivity and both temperature-dependent viscosity and thermal conductivity. The average Nusselt number decreases with an increase of Hartmann number. It is observed that the density inversion of water leaves strong effects on fluid flow and heat transfer due to the formation of bi-cellular structure. The heat transfer rate behaves non-linearly with density inversion parameter. The direction of external magnetic field also affect the fluid flow and heat transfer. (authors)

Densities and viscosities for ionic liquids mixtures containing [eOHmim][BF4], [bmim][BF4] and [bpy][BF4

International Nuclear Information System (INIS)

Song, Dayong; Chen, Jing

2014-01-01

Highlights: • Targets of this research are ILs mixtures. • Densities and viscosities were measured for three ILs mixtures. • Excess molar properties were deduced from the experiments. • Viscosities were discussed by the ideal Grunberg and Nissan mixing law. - Abstract: Densities and viscosities of binary ionic liquids mixtures, 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate ([eOHmim][BF 4 ]) + 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF 4 ]), 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate ([eOHmim][BF 4 ]) + N-butylpyridinium tetrafluoroborate ([bpy][BF 4 ]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF 4 ]) + N-butylpyridinium tetrafluoroborate ([bpy][BF 4 ]) were measured over the entire mole fraction from T = (298.15 to 343.15) K. The excess molar volumes were calculated and correlated by Redlich–Kiser polynomial expansions. The viscosities for pure ionic liquids were analyzed by means of the Vogel–Tammann–Fulcher equation and ideal mixing rules were applied for the ILs mixtures

Shear viscosities from Kubo formalism in a large-Nc Nambu-Jona-Lasinio model

International Nuclear Information System (INIS)

Lang, Robert; Kaiser, Norbert; Weise, Wolfram

2015-01-01

In this work the shear viscosity of strongly interacting matter is calculated within a two-flavor Nambu-Jona-Lasinio model as a function of temperature and chemical potential. The general Kubo formula is applied, incorporating the full Dirac structure of the thermal quark spectral function and avoiding commonly used on-shell approximations. Mesonic fluctuations contributing via Fock diagrams provide the dominant dissipative processes. The resulting ratio η/s (shear viscosity over entropy density) decreases with temperature and chemical potential. Interpolating between our NJL results at low temperatures and hard thermal loop results at high temperatures a minimum slightly above the AdS/CFT benchmark η/s = 1/4τ is obtained. (orig.)

Field device to measure viscosity, density, and other slurry properties in drilled shafts : final report.

Science.gov (United States)

2016-04-01

Proper performance of mineral slurries used to stabilize drilled shaft excavations is maintained by assuring the : density, viscosity, pH, and sand content stay within state specified limits. These limits have been set either by : past experience, re...

Shear viscosity to entropy density ratio in nuclear multifragmentation

International Nuclear Information System (INIS)

Pal, Subrata

2010-01-01

Nuclear multifragmentation in intermediate-energy heavy-ion collisions has long been associated with liquid-gas phase transition. We calculate the shear viscosity to entropy density ratio η/s for an equilibrated system of nucleons and fragments produced in multifragmentation within an extended statistical multifragmentation model. The temperature dependence of η/s exhibits behavior surprisingly similar to that of H 2 O. In the coexistence phase of fragments and light particles, the ratio η/s reaches a minimum of depth comparable to that for water in the vicinity of the critical temperature for liquid-gas phase transition. The effects of freeze-out volume and surface symmetry energy on η/s in multifragmentation are studied.

Density and viscosity study of nicotinic acid and nicotinamide in dilute aqueous solutions at and around the temperature of the maximum density of water

International Nuclear Information System (INIS)

Dhondge, Sudhakar S.; Dahasahasra, Prachi N.; Paliwal, Lalitmohan J.; Deshmukh, Dinesh W.

2014-01-01

Highlights: • Volumetric and transport behaviour of aqueous solutions of important vitamins are reported. • Various interactions of nicotinic acid and nicotinamide with water have been reported. • The temperature dependence of interactions between solute and solvent is discussed. • The study indicates that nicotinamide is more hydrated as compared to nicotinic acid. - Abstract: In the present study, we report experimental densities (ρ) and viscosities (η) of aqueous solutions of nicotinic acid and nicotinamide within the concentration range (0 to 0.1) mol · kg −1 at T = (275.15, 277.15 and 279.15) K. These parameters are then used to obtain thermodynamic and transport functions such as apparent molar volume of solute (V ϕ ), limiting apparent molar volume of solute (V ϕ 0 ), limiting apparent molar expansivity of solute (E ϕ 0 ), coefficient of thermal expansion (α ∗ ), Jones–Dole equation viscosity A, B and D coefficients, temperature derivative of B coefficient i.e. (dB/dT) and hydration number (n H ), etc. The activation parameters of viscous flow for the binary mixtures have been determined and discussed in terms of Eyring’s transition state theory. These significant parameters are helpful to study the structure promoting or destroying tendency of solute and various interactions present in (nicotinic acid + water) and (nicotinamide + water) binary mixtures

Viscosity and density data for the ternary system water(1)–ethanol(2)–ethylene glycol(3) between 298.15 K and 328.15 K

International Nuclear Information System (INIS)

Quijada-Maldonado, E.; Meindersma, G.W.; Haan, A.B. de

2013-01-01

Highlights: ► We measure density and dynamic viscosity of pure ethylene glycol. ► We measure ternary densities with water and ethanol. ► We measure ternary dynamic viscosities with water and ethanol. ► The Eyring–Patel–Teja model correlate well ternary viscosities. ► We predict ternary dynamic viscosities with the ASOG-VISCO model. - Abstract: Ethylene glycol is an organic solvent used in extractive distillation to separate water–ethanol mixtures. An appropriate process description requires accurate physical property data. In this paper, experimental liquid densities and dynamic viscosities of pure ethylene glycol as well as the ternary system water–ethanol–ethylene glycol are presented over a wide temperature range (298.15 K to 328.15 K) at atmospheric pressure. A quadratic mixing rule was used to correlate the ternary liquid densities. The Eyring–Patel–Teja model with two Margules-type mixing rules for polar and aqueous systems is used to correlate the dynamic viscosity data over the measured ternary compositions and temperatures. An excellent agreement with experimental data is obtained. Additionally, the predictive ASOG-VISCO model demonstrated a good representation of the experimental data.

Density, viscosity, and N2O solubility of aqueous amino acid salt and amine amino acid salt solutions

International Nuclear Information System (INIS)

Aronu, Ugochukwu E.; Hartono, Ardi; Svendsen, Hallvard F.

2012-01-01

Highlights: ► Density of amino acid salt and amine amino acid salt. ► Viscosity of amino acid salt and amine amino acid salt. ► Henry’s law constant/N 2 O solubility of amino acid salt and amine amino acid salt. ► Schumpe model. Correlations for density, viscosity, and N 2 O solubility. - Abstract: Physicochemical properties of aqueous amino acid salt (AAS), potassium salt of sarcosine (KSAR) and aqueous amine amino acid salt (AAAS), 3-(methylamino)propylamine/sarcosine (SARMAPA) have been studied. Densities of KSAR were measured for sarcosine mole fraction 0.02 to 0.25 for temperature range 298.15 K to 353.15 K, the viscosities were measured for 0.02 to 0.10 mole fraction sarcosine (293.15 K to 343.15 K) while the N 2 O solubilities were measured from 0.02 to 0.10 mole fraction sarcosine solutions (298.15 K to 363.15 K). Densities of SARMAPA were measured for sarcosine mole fraction 0.02 to 0.23 for temperature range (298.15 K to 353.15 K), viscosities were measured for 0.02 to 0.16 mole fraction sarcosine (293.15 K to 343.15 K) while the N 2 O solubilities were measured from 0.02 to 0.16 mole fraction sarcosine solutions (298.15 K to 343.15 K). Experimental results were correlated well with empirical correlations and N 2 O solubility results for KSAR were predicted adequately by a Schumpe model. The solubilities of N 2 O in AAS and AAAS are significantly lower than values for amines. The solubilities vary as: amine > AAAS > AAS.

Modeling the effects of the variability of temperature-related dynamic viscosity on the thermal-affected zone of groundwater heat-pump systems

Science.gov (United States)

Lo Russo, Stefano; Taddia, Glenda; Cerino Abdin, Elena

2018-01-01

Thermal perturbation in the subsurface produced in an open-loop groundwater heat pump (GWHP) plant is a complex transport phenomenon affected by several factors, including the exploited aquifer's hydrogeological and thermal characteristics, well construction features, and the temporal dynamics of the plant's groundwater abstraction and reinjection system. Hydraulic conductivity has a major influence on heat transport because plume propagation, which occurs primarily through advection, tends to degrade following conductive heat transport and convection within moving water. Hydraulic conductivity is, in turn, influenced by water reinjection because the dynamic viscosity of groundwater varies with temperature. This paper reports on a computational analysis conducted using FEFLOW software to quantify how the thermal-affected zone (TAZ) is influenced by the variation in dynamic viscosity due to reinjected groundwater in a well-doublet scheme. The modeling results demonstrate non-negligible groundwater dynamic-viscosity variation that affects thermal plume propagation in the aquifer. This influence on TAZ calculation was enhanced for aquifers with high intrinsic permeability and/or substantial temperature differences between abstracted and post-heat-pump-reinjected groundwater.

The Thermal Entropy Density of Spacetime

Directory of Open Access Journals (Sweden)

Rongjia Yang

2013-01-01

Full Text Available Introducing the notion of thermal entropy density via the first law of thermodynamics and assuming the Einstein equation as an equation of thermal state, we obtain the thermal entropy density of any arbitrary spacetime without assuming a temperature or a horizon. The results confirm that there is a profound connection between gravity and thermodynamics.

Effect of magnetic field on thermal conductivity and viscosity of a magnetic nanofluid loaded with carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

Shahsavar, Amin [Kermanshah University of Technology, Kermanshah (Iran, Islamic Republic of); Salimpour, Mohammad Reza; Saghafian, Mohsen [Isfahan University of Technology, Isfahan (Iran, Islamic Republic of); Shafii, M. B. [Sharif University of Technology, Tehran(Iran, Islamic Republic of)

2016-02-15

The present work examines experimentally the effect of magnetic field on the viscosity and thermal conductivity of a hybrid nanofluid containing tetramethylammonium hydroxide (TMAH) coated Fe{sub 3}O{sub 4} nanoparticles and Gum arabic (GA) coated carbon nanotubes (CNTs). The hybrid nanofluid was prepared by using ultrasonic dispersion method. Magnetic field was created by a pair of spaced apart magnet plates. The effect of temperature on the time variation of thermal conductivity under applied magnetic field was also investigated. According to the results of this study, viscosity of the hybrid nanofluid increases with the strength of magnetic field, while it decreases with the increase of temperature. Additionally, it is found that the hybrid nanofluid behaves as a shear thinning fluid at low shear rates while it exhibits Newtonian behavior at high shear rates. Furthermore, results show that when an external magnetic field is applied to the studied magnetic nanofluids, the thermal conductivity experiences a peak.

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.

Viscosity Meaurement Technique for Metal Fuels

International Nuclear Information System (INIS)

Ban, Heng

2015-01-01

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.

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.

Density, viscosity, isothermal (vapour + liquid) equilibrium, excess molar volume, viscosity deviation, and their correlations for chloroform + methyl isobutyl ketone binary system

International Nuclear Information System (INIS)

Clara, Rene A.; Gomez Marigliano, Ana C.; Solimo, Horacio N.

2007-01-01

Density and viscosity measurements for pure chloroform and methyl isobutyl ketone at T = (283.15, 293.15, 303.15, and 313.15) K as well as for the binary system {x 1 chloroform + (1 - x 1 ) methyl isobutyl ketone} at the same temperatures were made over the whole concentration range. The experimental results were fitted to empirical equations, which permit the calculation of these properties over the whole concentration and temperature ranges studied. Data of the binary mixture were further used to calculate the excess molar volume and viscosity deviation. The (vapour + liquid) equilibrium (VLE) at T = 303.15 K for this binary system was also measured in order to calculate the activity coefficients and the excess molar Gibbs energy. This binary system shows no azeotrope and negative deviations from ideal behaviour. The excess or deviation properties were fitted to the Redlich-Kister polynomial relation to obtain their coefficients and standard deviations

Densities, refractive indices, and viscosities of N,N-diethylethanol ammonium chloride–glycerol or –ethylene glycol deep eutectic solvents and their aqueous solutions

International Nuclear Information System (INIS)

Siongco, Kathrina R.; Leron, Rhoda B.; Li, Meng-Hui

2013-01-01

Highlights: • The densities, refractive indices, and viscosities of aqueous DES solutions were measured. • DES are made from N,N-diethylethanol ammonium chloride + glycerol or ethylene glycol. • The temperature studied was (298.15 to 343.15) K. • The measured data were reported as functions of temperature and composition. • The measured data were represented satisfactorily by the applied correlations. -- Abstract: In this work, we report new experimental data on density, ρ, refractive index, n D, and viscosity, η, of two deep eutectic solvents, N,N-diethylethanol ammonium chloride–glycerol (DEACG) and N,N-diethylethanol ammonium chloride–ethylene glycol (DEACEG), and their aqueous solutions, over the complete composition range, at temperatures from (298.15 to 343.15) K. Densities and viscosities were measured using the vibrating tube and the falling ball techniques, respectively, while the refractive index at the sodium D line was measured using an automatic refractometer. We aimed to represent the measured properties as a function of temperature and composition, and correlated them using the Redlich–Kister-type equation, for density, a polynomial function, for refractive index, and the Vogel–Fulcher–Tammann (VFT) equation, for viscosity

Drifting solutions with elliptic symmetry for the compressible Navier-Stokes equations with density-dependent viscosity

International Nuclear Information System (INIS)

An, Hongli; Yuen, Manwai

2014-01-01

In this paper, we investigate the analytical solutions of the compressible Navier-Stokes equations with dependent-density viscosity. By using the characteristic method, we successfully obtain a class of drifting solutions with elliptic symmetry for the Navier-Stokes model wherein the velocity components are governed by a generalized Emden dynamical system. In particular, when the viscosity variables are taken the same as Yuen [M. W. Yuen, “Analytical solutions to the Navier-Stokes equations,” J. Math. Phys. 49, 113102 (2008)], our solutions constitute a generalization of that obtained by Yuen. Interestingly, numerical simulations show that the analytical solutions can be used to explain the drifting phenomena of the propagation wave like Tsunamis in oceans

Distributed thermal micro sensors for fluid flow

NARCIS (Netherlands)

van Baar, J.J.J.

2002-01-01

In this thesis thermal sensor-actuator structures are proposed for measuring the parameters pressure p, dynamic viscosity μ, thermal conductivity , specific heat c, density and the fluid velocity v. In this chapter examples will be given of the added value of many identical simple elements and the

Containerless Measurements of Density and Viscosity of Fe-Co Alloys

Science.gov (United States)

Lee, Jonghyun; Choufani, Paul; Bradshaw, Richard C.; Hyers, Robert W.; Matson, Douglas M.

2012-01-01

During the past years, extensive collaborative research has been done to understand phase selection in undercooled metals using novel containerless processing techniques such as electrostatic and electromagnetic levitation. Of major interest is controlling a two-step solidification process, double recalescence, in which the metastable phase forms first and then transforms to the stable phase after a certain delay time. The previous research has shown that the delay time is greatly influenced by the internal convection velocity. In the prediction of internal flow, the fidelity of the results depends on the accuracy of the material properties. This research focuses on the measurements of density and viscosity of Fe-Co alloys which will be used for the fluid simulations whose results will support upcoming International Space Station flight experiments.

The Viscosity of Organic Liquid Mixtures

Science.gov (United States)

Len, C. W.; Trusler, J. P. M.; Vesovic, V.; Wakeham, W. A.

2006-01-01

The paper reports measurements of the viscosity and density of two heavy hydrocarbon mixtures, Dutrex and Arab Light Flashed Distillate (ALFD), and of their mixtures with hydrogen. The measurements have been carried out with a vibrating-wire device over a range of temperatures from 399 to 547 K and at pressures up to 20 MPa. Measurements have also been carried out on systems in which hydrogen at different concentrations has been dissolved in the liquids. The measurements have an estimated uncertainty of ±5% for viscosity and ±2% for density and represent the first results on these prototypical heavy hydrocarbons. The results reveal that the addition of hydrogen reduces both the density and viscosity of the original hydrocarbon mixture at a particular temperature and pressure.

Density, viscosity, and surface tension of synthesis grade imidazolium,pyridinium, and pyrrolidinium based room temperature ionic liquids

NARCIS (Netherlands)

Galan Sanchez, L.M.; Espel, J.R.; Onink, S.A.F.; Meindersma, G.W.; Haan, de A.B.

2009-01-01

Density, viscosity, and surface tension data sets of 13 ionic liquids formed by imidazolium, pyridinium, or pyrrolidinium cations paired with dicyanamide (DCA), tetrafluoroborate (BF4¯), thiocyanate (SCN¯),methylsulfate (MeSO4¯), and trifluoroacetate (TFA) anions are reported. The properties were

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. 

Numerical solution of problems concerning the thermal convection of a variable-viscosity liquid

Science.gov (United States)

Zherebiatev, I. F.; Lukianov, A. T.; Podkopaev, Iu. L.

A stabilizing-correction scheme is constructed for integrating the fourth-order equation describing the dynamics of a viscous incompressible liquid. As an example, a solution is obtained to the problem of the solidification of a liquid in a rectangular region with allowance for convective energy transfer in the liquid phase as well as temperature-dependent changes of viscosity. It is noted that the proposed method can be used to study steady-state problems of thermal convection in ingots obtained through continuous casting.

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.

Combined effect of thermal dispersion and variable viscosity of non-darcy convection heat transfer in a fluidsaturated porous medium

KAUST Repository

El-Amin, Mohamed; Salama, Amgad; El-Amin, Ammaarah A.; Gorla, Rama Subba Reddy

2013-01-01

In this paper, the effects of thermal dispersion and variable viscosity on the non-Darcy free, mixed, and forced convection heat transfer along a vertical flat plate embedded in a fluid-saturated porous medium are investigated. Forchheimer extension

Fluctuation expressions for fast thermal transport processes: Vortex viscosity

International Nuclear Information System (INIS)

Evans, D.J.; Hanley, H.J.M.

1982-01-01

The vortex viscosity of a model diatomic fluid is calculated using both equilibrium and nonequilibrium molecular dynamics. The two calculations agree within statistical uncertainties. The results show that vortex viscosity does not have a conventional Kubo-Green relation. An argument as to why this is so is presented

Measurement and study of density, surface tension, and viscosity of quaternary ammonium-based ionic liquids ([N222(n)]Tf2N)

International Nuclear Information System (INIS)

Ghatee, Mohammad Hadi; Bahrami, Maryam; Khanjari, Neda

2013-01-01

Highlights: • Characterization of high purity synthesized alkyl quaternary ammonium ionic liquids. • Measurement of temperature dependent surface tension, density, viscosity and critical point. • Systematic increase of surface energy and surface entropy having plateau at high chain length. • Accurate application of VFT and fluidity equations to temperature dependent viscosities. • Particular variation of fluidity exponent with a plateau at high alkyl chain length. -- Abstract: In this work five quaternary ammonium-based ionic liquids with bis(trifluoromethylsulfonyl)imide anion were synthesized and their density, viscosity and surface tensions were measured in the temperature range (298 to 373) K. Surface tensions were measured by capillary rise method using a homemade capillary apparatus, in which the liquid/vapor can be brought into equilibrium practically. Measurements of viscosities and surface tensions were performed under water–vapor free atmosphere. The surface tension of quaternary ammonium-based ILs decreases as the alkyl chain length increases. Also surface energy and surface entropy are found as increasing functions of alkyl chain length with a plateau at high lengths in the surface. The viscosities measured by capillary viscometer fit in VFT equation, indication of non-Arrhenius ionic liquids. Viscosities are also fitted quite accurately in the relation we have developed recently as the fluidity equation with the characteristics exponent ϕ. Values of ϕ for ionic liquids are close to one another and tend to the limiting value, almost 0.328, asymptotically as the alkyl chain length increases. The critical temperatures predicted via the temperature dependent surface tensions decrease with increasing alkyl chain length of the cation. The trend of predicted critical temperature of these ionic liquids conforms to those of imidazolium-based ILs

Cavitation and thermal dilepton production in QGP

International Nuclear Information System (INIS)

Bhatt, Jitesh R.; Mishra, Hiranmaya; Sreekanth, V.

2012-01-01

We study the effects of bulk and shear viscosities on both hydrodynamical evolution and thermal dilepton emission rate from the QGP phase at RHIC energies. We use lattice QCD inspired parametrization for the bulk viscosity and trace anomaly (equation of state) to describe behavior of the system near the critical temperature T c . Ratio of the shear viscosity to entropy density is taken to be η/s∼1/4π. We calculate the corrections on the dilepton production rates due to modification in the distribution function, arising due to the presence of the bulk and shear viscosities. It is shown that when the system temperature evolves close to T c the effect of the bulk viscosity on the dilepton emission rates cannot be ignored. It is demonstrated that the bulk viscosity can suppress the thermal dilepton spectra where as the effect of the shear viscosity is to enhance it. Further we show that the bulk viscosity driven fragmentation or cavitation can set in very early during the hydrodynamical evolution and this in turn would make the hydrodynamical treatment invalid beyond the cavitation time. We find that even though the finite bulk viscosity corrections and the onset of the cavitation reduce the production rates, the effect of the minimal η/s=1/4π can enhance the dilepton production rates significantly in the regime p T ⩾2 GeV.

Electrically and Thermally Conductive Low Density Polyethylene-Based Nanocomposites Reinforced by MWCNT or Hybrid MWCNT/Graphene Nanoplatelets with Improved Thermo-Oxidative Stability

Directory of Open Access Journals (Sweden)

Sandra Paszkiewicz

2018-04-01

Full Text Available In this paper, the electrical and thermal conductivity and morphological behavior of low density polyethylene (LDPE/multi-walled carbon nanotubes (MWCNTs + graphene nanoplatelets (GNPs hybrid nanocomposites (HNCs have been studied. The distribution of MWCNTs and the hybrid of MWCNTs/GNPs within the polymer matrix has been investigated with scanning electron microscopy (SEM. The results showed that the thermal and electrical conductivity of the LDPE-based nanocomposites increased along with the increasing content of carbon nanofillers. However, one could observe greater improvement in the thermal and electrical conductivity when only MWCNTs have been incorporated. Moreover, the improvement in tensile properties and thermal stability has been observed when carbon nanofillers have been mixed with LDPE. At the same time, the increasing content of MWCNTs and MWCNTs/GNPs caused an increase in the melt viscosity with only little effect on phase transition temperatures.

Electrically and Thermally Conductive Low Density Polyethylene-Based Nanocomposites Reinforced by MWCNT or Hybrid MWCNT/Graphene Nanoplatelets with Improved Thermo-Oxidative Stability.

Science.gov (United States)

Paszkiewicz, Sandra; Szymczyk, Anna; Pawlikowska, Daria; Subocz, Jan; Zenker, Marek; Masztak, Roman

2018-04-22

In this paper, the electrical and thermal conductivity and morphological behavior of low density polyethylene (LDPE)/multi-walled carbon nanotubes (MWCNTs) + graphene nanoplatelets (GNPs) hybrid nanocomposites (HNCs) have been studied. The distribution of MWCNTs and the hybrid of MWCNTs/GNPs within the polymer matrix has been investigated with scanning electron microscopy (SEM). The results showed that the thermal and electrical conductivity of the LDPE-based nanocomposites increased along with the increasing content of carbon nanofillers. However, one could observe greater improvement in the thermal and electrical conductivity when only MWCNTs have been incorporated. Moreover, the improvement in tensile properties and thermal stability has been observed when carbon nanofillers have been mixed with LDPE. At the same time, the increasing content of MWCNTs and MWCNTs/GNPs caused an increase in the melt viscosity with only little effect on phase transition temperatures.

Density, viscosity and excess molar volume of binary mixtures of tri-n-octylamine + diluents (n-heptane, n-octane, n-nonane, and n-decane) at various temperatures

International Nuclear Information System (INIS)

Fang, Sheng; Zuo, Xiao-Bo; Xu, Xue-Jiao; Ren, Da-Hai

2014-01-01

Highlights: • Densities and viscosities of tri-n-octylamine + n-heptane, +n-octane, +n-nonane, or +n-decane are determined. • The excess molar volume is calculated. • The Grunberg and Nissan equation and Fang and He equation are used to correlate the binary viscosities. -- Abstract: Densities (ρ) and viscosities (η) for binary mixtures of tri-n-octylamine (TOA) + n-heptane, TOA + n-octane, TOA + n-nonane, and TOA + n-decane are determined at T (283.15, 293.15, and 303.15) K and atmospheric pressure. The excess molar volume is calculated from the density data and is correlated by a Redlich–Kister type equation. The excess molar volume is negative for all the four systems. The results show that the volume accommodation effect is predominant in these systems. The Grunberg and Nissan equation and Fang and He equation for binary mixtures are used to correlate the experimental viscosity data. The Fang and He equation gives an average absolute deviation (AAD%) of 0.8% for TOA with alkane mixtures, better than that of 3.8% given by the Grunberg and Nissan equation

Combined effect of thermal dispersion and variable viscosity of non-darcy convection heat transfer in a fluidsaturated porous medium

KAUST Repository

El-Amin, Mohamed

2013-01-01

In this paper, the effects of thermal dispersion and variable viscosity on the non-Darcy free, mixed, and forced convection heat transfer along a vertical flat plate embedded in a fluid-saturated porous medium are investigated. Forchheimer extension is employed in the flow equation to express the non-Darcy model. The fluid viscosity varies as an inverse linear function of temperature. The coefficient of thermal diffusivity has been assumed to be the sum of the molecular diffusivity and the dynamic diffusivity due to mechanical dispersion. Similarity solutions of the governing equations, for an isothermally heated plate, are obtained. Effects of the physical parameters, which govern the problem, on the rate of heat transfer in terms of Nusselt number, the slip velocity, and the boundary layer thickness, for the two cases Darcy and non-Darcy, are shown on graphs or entered in tables. © 2013 by Begell House, Inc.

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...

High Temperature, high pressure equation of state density correlations and viscosity correlations

Energy Technology Data Exchange (ETDEWEB)

Tapriyal, D.; Enick, R.; McHugh, M.; Gamwo, I.; Morreale, B.

2012-07-31

Global increase in oil demand and depleting reserves has derived a need to find new oil resources. To find these untapped reservoirs, oil companies are exploring various remote and harsh locations such as deep waters in Gulf of Mexico, remote arctic regions, unexplored deep deserts, etc. Further, the depth of new oil/gas wells being drilled has increased considerably to tap these new resources. With the increase in the well depth, the bottomhole temperature and pressure are also increasing to extreme values (i.e. up to 500 F and 35,000 psi). The density and viscosity of natural gas and crude oil at reservoir conditions are critical fundamental properties required for accurate assessment of the amount of recoverable petroleum within a reservoir and the modeling of the flow of these fluids within the porous media. These properties are also used to design appropriate drilling and production equipment such as blow out preventers, risers, etc. With the present state of art, there is no accurate database for these fluid properties at extreme conditions. As we have begun to expand this experimental database it has become apparent that there are neither equations of state for density or transport models for viscosity that can be used to predict these fundamental properties of multi-component hydrocarbon mixtures over a wide range of temperature and pressure. Presently, oil companies are using correlations based on lower temperature and pressure databases that exhibit an unsatisfactory predictive capability at extreme conditions (e.g. as great as {+-} 50%). From the perspective of these oil companies that are committed to safely producing these resources, accurately predicting flow rates, and assuring the integrity of the flow, the absence of an extensive experimental database at extreme conditions and models capable of predicting these properties over an extremely wide range of temperature and pressure (including extreme conditions) makes their task even more daunting.

Viscosity and thermal conductivity of the alternative refrigerant 1,1-difluorethane (R152a); Viskositaet und Waermeleitfaehigkeit des alternativen Kaeltemittels 1,1-Difluorethan (R152a)

Energy Technology Data Exchange (ETDEWEB)

Krauss, R. [Inst. fuer Technische Thermodynamik und Thermische Verfahrenstechnik, Univ. Stuttgart (Germany); Stephan, K. [Inst. fuer Technische Thermodynamik und Thermische Verfahrenstechnik, Univ. Stuttgart (Germany)

1995-12-31

This contribution presents practice-oriented equations for calculating the viscosity and thermal conductivity of the environmentally acceptable refrigerant 1,1 difluoroethane (R 152a). The equations are based on an evaluation method which takes all available measurement series into account. The selected values were described by means of the so-called residual amount principle according to which the transport properties are divided into density-dependent and density-independent contributions. As there is no thermal state equation for the near-critical region, it was not possible to make a theoretically founded evaluation of heat conductivity there. Furthermore some measured values far off the saturation line showed a critical anomaly and therefore had to be excluded from the evaluation. The residual amount of thermal conductivity had to be divided among two equations one for the subcritical and one for the supercritical region. In contrast to this, a single function sufficed to describe the residual amount of viscosity for the whole liquid phase region. In some cases the evaluation revealed considerable inconsistencies between the measurement series of different laboratories which cannot be attributed to the measuring incertainties referred to by the authors. (orig.) [Deutsch] Es werden praxisorientierte Berechnungsgleichungen fuer die Viskositaet und die Waermeleitfaehigkeit des umweltfreundlichen Kaeltemittels 1,1-Difluorethan (R152a) vorgestellt, denen ein Auswertungsverfahren zugrunde liegt, das alle verfuegbaren Messreihen beruecksichtigt. Die ausgewaehlten Werte wurden mit Hilfe des sogenannten Restgroessenprinzipes beschrieben, das die Transporteigenschaften in dichteunabhaengige und dichteabhaengige Beitraege aufteilt. Da fuer das nah-kritische Gebiet keine thermische Zustandsgleichung existiert, war eine theoretisch begruendete Auswertung der Waermeleitfaehigkeit in diesem Bereich nicht moeglich, und einige Messwerte abseits der Saettigungslinie, die eine

Densities and Kinematic Viscosities for the Systems Benzene + Methyl Formate, Benzene + Ethyl Formate, Benzene + Propyl Formate, and Benzene + Butyl Formate

DEFF Research Database (Denmark)

Emmerling, Uwe; Rasmussen, Peter

1998-01-01

a Redlich-Kister type of expression with temperature-independent parameters and the data for the systems benzene + ethyl formate, benzene + propyl formate, and benzene + butyl formate with temperature-dependent parameters. The viscosities have furthermore been compared to values predicted by means of the GC......Densities and kinematic viscosities have been measured for the system benzene + methyl formate at 20°C and for the systems benzene + ethyl formate, benzene + propyl formate, and benzene + butyl formate from 20°C to 50°C. The results for the system benzene + methyl formate have been correlated using...

Density and viscosity modeling and characterization of heavy oils

DEFF Research Database (Denmark)

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

2005-01-01

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

Solution for laminar natural convection flows in a square cavity with temperature dependent viscosity

Energy Technology Data Exchange (ETDEWEB)

Sanchez, J.G. [Parsons Brinckerhoff, New York, NY (United States)

1995-12-31

This paper presents an examination of numerical results for the buoyancy-driven convection heat transfer problem, in a two-dimensional enclosure under steady-state, laminar, incompressible, and temperature dependent viscosity fluid flow conditions. The vertical walls are exposed to different temperatures and the top and bottom are insulated. Rayleigh numbers of 10{sup 4}, 10{sup 5}, and 10{sup 6} are considered. Specific heat, thermal conductivity, and the thermal expansion coefficient are assumed constant. Density variation is included using the Oberbeck-Boussinesq approximation. The results are obtained using the SIMPLEC solution technique based on a power-law, finite-volume discretization scheme. The hydrodynamic and thermal fields are presented at various locations in the enclosures.

Transport properties in mixtures involving carbon dioxide at low and moderate density: test of several intermolecular potential energies and comparison with experiment

Science.gov (United States)

Moghadasi, Jalil; Yousefi, Fakhri; Papari, Mohammad Mehdi; Faghihi, Mohammad Ali; Mohsenipour, Ali Asghar

2009-09-01

It is the purpose of this paper to extract unlike intermolecular potential energies of five carbon dioxide-based binary gas mixtures including CO2-He, CO2-Ne, CO2-Ar, CO2-Kr, and CO2-Xe from viscosity data and compare the calculated potentials with other models potential energy reported in literature. Then, dilute transport properties consisting of viscosity, diffusion coefficient, thermal diffusion factor, and thermal conductivity of aforementioned mixtures are calculated from the calculated potential energies and compared with literature data. Rather accurate correlations for the viscosity coefficient of afore-cited mixtures embracing the temperature range 200 K < T < 3273.15 K is reproduced from the present unlike intermolecular potentials energy. Our estimated accuracies for the viscosity are to within ±2%. In addition, the calculated potential energies are used to present smooth correlations for other transport properties. The accuracies of the binary diffusion coefficients are of the order of ±3%. Finally, the unlike interaction energy and the calculated low density viscosity have been employed to calculate high density viscosities using Vesovic-Wakeham method.

Transport properties in mixtures involving carbon dioxide at low and moderate density: test of several intermolecular potential energies and comparison with experiment

Energy Technology Data Exchange (ETDEWEB)

Moghadasi, Jalil; Yousefi, Fakhri [Shiraz University, Department of Chemistry, Shiraz (Iran); Papari, Mohammad Mehdi; Faghihi, Mohammad Ali [Shiraz University of Technology, Department of Chemistry, Shiraz (Iran); Mohsenipour, Ali Asghar [University of Waterloo, Department of Chemical Engineering, Waterloo (Canada)

2009-09-15

It is the purpose of this paper to extract unlike intermolecular potential energies of five carbon dioxide-based binary gas mixtures including CO{sub 2}-He, CO{sub 2}-Ne, CO{sub 2}-Ar, CO{sub 2}-Kr, and CO{sub 2}-Xe from viscosity data and compare the calculated potentials with other models potential energy reported in literature. Then, dilute transport properties consisting of viscosity, diffusion coefficient, thermal diffusion factor, and thermal conductivity of aforementioned mixtures are calculated from the calculated potential energies and compared with literature data. Rather accurate correlations for the viscosity coefficient of afore-cited mixtures embracing the temperature range 200 Kviscosity are to within {+-}2%. In addition, the calculated potential energies are used to present smooth correlations for other transport properties. The accuracies of the binary diffusion coefficients are of the order of {+-}3%. Finally, the unlike interaction energy and the calculated low density viscosity have been employed to calculate high density viscosities using Vesovic-Wakeham method. (orig.)

Whole-blood viscosity and the insulin-resistance syndrome.

Science.gov (United States)

Høieggen, A; Fossum, E; Moan, A; Enger, E; Kjeldsen, S E

1998-02-01

In a previous study we found that elevated blood viscosity was linked to the insulin resistance syndrome, and we proposed that high blood viscosity may increase insulin resistance. That study was based on calculated viscosity. To determine whether directly measured whole-blood viscosity was related to the insulin-resistance syndrome in the same way as calculated viscosity had been found to be. Healthy young men were examined with the hyperinsulinemic isoglycemic glucose clamp technique, and we related insulin sensitivity (glucose disposal rate) to other metabolic parameters and to blood viscosity. We established a technique for direct measurement of whole-blood viscosity. There were statistically significant negative correlations between glucose disposal rate and whole-blood viscosity at low and high shear rates (r = -0.41, P = 0.007 for both, n = 42). Whole-blood viscosity was correlated positively (n = 15) to serum triglyceride (r = 0.54, P = 0.04) and total cholesterol (r = 0.52, P = 0.05), and negatively with high-density lipoprotein cholesterol (r = -0.53, P = 0.04) concentrations. Insulin sensitivity index was correlated positively to high-density lipoprotein cholesterol (r = 0.54, P = 0.04) and negatively to serum triglyceride (r = -0.69, P = 0.005) and to total cholesterol (r = -0.81, P = 0.0003) concentrations. The present results demonstrate for the first time that there is a negative relationship between directly measured whole-blood viscosity and insulin sensitivity as a part of the insulin-resistance syndrome. Whole-blood viscosity contributes to the total peripheral resistance, and these results support the hypothesis that insulin resistance has a hemodynamic basis.

A numerical model for density-and-viscosity-dependent flows in two-dimensional variably saturated porous media

Science.gov (United States)

Boufadel, Michel C.; Suidan, Makram T.; Venosa, Albert D.

1999-04-01

We present a formulation for water flow and solute transport in two-dimensional variably saturated media that accounts for the effects of the solute on water density and viscosity. The governing equations are cast in a dimensionless form that depends on six dimensionless groups of parameters. These equations are discretized in space using the Galerkin finite element formulation and integrated in time using the backward Euler scheme with mass lumping. The modified Picard method is used to linearize the water flow equation. The resulting numerical model, the MARUN model, is verified by comparison to published numerical results. It is then used to investigate beach hydraulics at seawater concentration (about 30 g l -1) in the context of nutrients delivery for bioremediation of oil spills on beaches. Numerical simulations that we conducted in a rectangular section of a hypothetical beach revealed that buoyancy in the unsaturated zone is significant in soils that are fine textured, with low anisotropy ratio, and/or exhibiting low physical dispersion. In such situations, application of dissolved nutrients to a contaminated beach in a freshwater solution is superior to their application in a seawater solution. Concentration-engendered viscosity effects were negligible with respect to concentration-engendered density effects for the cases that we considered.

Jet collimation by turbulent viscosity. I

International Nuclear Information System (INIS)

Henriksen, R.N.

1987-01-01

In this paper it is assumed that the subscale turbulent eddies induced in an ambient medium by the emergence of a (already collimated) jet from a galactic nucleus (VLBI jet) are the source of the viscosity which causes material to be entrained into the large-scale (VLA) jet. New analytic solutions are derived by a generalization of the self-similar Ansatz used in the Landau-Squires solution to include variable density and viscosity. It is shown that such a process of viscous collimation of the VLA jets can account for the observed collimation-luminosity correlation, the magnetic flux, and the inferred mass flux of these jets. Order of magnitude comparisons of velocity and density fields with recently observed emission-line flow regions near radio jets are made. All of the viscosity-dependent observational checks imply roughly the same plausible value for the eddy viscosity. It is emphasized that storing the initial VLBI jet energy in the intermediate scales occupied by the turbulent eddies allows this energy to be largely undetected. 35 references

An efficient scheme for a phase field model for the moving contact line problem with variable density and viscosity

KAUST Repository

Gao, Min

2014-09-01

In this paper, we develop an efficient numerical method for the two phase moving contact line problem with variable density, viscosity, and slip length. The physical model is based on a phase field approach, which consists of a coupled system of the Cahn-Hilliard and Navier-Stokes equations with the generalized Navier boundary condition [1,2,5]. To overcome the difficulties due to large density and viscosity ratio, the Navier-Stokes equations are solved by a splitting method based on a pressure Poisson equation [11], while the Cahn-Hilliard equation is solved by a convex splitting method. We show that the method is stable under certain conditions. The linearized schemes are easy to implement and introduce only mild CFL time constraint. Numerical tests are carried out to verify the accuracy, stability and efficiency of the schemes. The method allows us to simulate the interface problems with extremely small interface thickness. Three dimensional simulations are included to validate the efficiency of the method. © 2014 Elsevier Inc.

An efficient scheme for a phase field model for the moving contact line problem with variable density and viscosity

KAUST Repository

Gao, Min; Wang, Xiao-Ping

2014-01-01

In this paper, we develop an efficient numerical method for the two phase moving contact line problem with variable density, viscosity, and slip length. The physical model is based on a phase field approach, which consists of a coupled system of the Cahn-Hilliard and Navier-Stokes equations with the generalized Navier boundary condition [1,2,5]. To overcome the difficulties due to large density and viscosity ratio, the Navier-Stokes equations are solved by a splitting method based on a pressure Poisson equation [11], while the Cahn-Hilliard equation is solved by a convex splitting method. We show that the method is stable under certain conditions. The linearized schemes are easy to implement and introduce only mild CFL time constraint. Numerical tests are carried out to verify the accuracy, stability and efficiency of the schemes. The method allows us to simulate the interface problems with extremely small interface thickness. Three dimensional simulations are included to validate the efficiency of the method. © 2014 Elsevier Inc.

A new model for the accurate calculation of natural gas viscosity

Directory of Open Access Journals (Sweden)

Xiaohong Yang

2017-03-01

Full Text Available Viscosity of natural gas is a basic and important parameter, of theoretical and practical significance in the domain of natural gas recovery, transmission and processing. In order to obtain the accurate viscosity data efficiently at a low cost, a new model and its corresponding functional relation are derived on the basis of the relationship among viscosity, temperature and density derived from the kinetic theory of gases. After the model parameters were optimized using a lot of experimental data, the diagram showing the variation of viscosity along with temperature and density is prepared, showing that: ① the gas viscosity increases with the increase of density as well as the increase of temperature in the low density region; ② the gas viscosity increases with the decrease of temperature in high density region. With this new model, the viscosity of 9 natural gas samples was calculated precisely. The average relative deviation between these calculated values and 1539 experimental data measured at 250–450 K and 0.10–140.0 MPa is less than 1.9%. Compared with the 793 experimental data with a measurement error less than 0.5%, the maximum relative deviation is less than 0.98%. It is concluded that this new model is more advantageous than the previous 8 models in terms of simplicity, accuracy, fast calculation, and direct applicability to the CO2 bearing gas samples.

Cellular Viscosity in Prokaryotes and Thermal Stability of Low Molecular Weight Biomolecules.

Science.gov (United States)

Cuecas, Alba; Cruces, Jorge; Galisteo-López, Juan F; Peng, Xiaojun; Gonzalez, Juan M

2016-08-23

Some low molecular weight biomolecules, i.e., NAD(P)H, are unstable at high temperatures. The use of these biomolecules by thermophilic microorganisms has been scarcely analyzed. Herein, NADH stability has been studied at different temperatures and viscosities. NADH decay increased at increasing temperatures. At increasing viscosities, NADH decay rates decreased. Thus, maintaining relatively high cellular viscosity in cells could result in increased stability of low molecular weight biomolecules (i.e., NADH) at high temperatures, unlike what was previously deduced from studies in diluted water solutions. Cellular viscosity was determined using a fluorescent molecular rotor in various prokaryotes covering the range from 10 to 100°C. Some mesophiles showed the capability of changing cellular viscosity depending on growth temperature. Thermophiles and extreme thermophiles presented a relatively high cellular viscosity, suggesting this strategy as a reasonable mechanism to thrive under these high temperatures. Results substantiate the capability of thermophiles and extreme thermophiles (growth range 50-80°C) to stabilize and use generally considered unstable, universal low molecular weight biomolecules. In addition, this study represents a first report, to our knowledge, on cellular viscosity measurements in prokaryotes and it shows the dependency of prokaryotic cellular viscosity on species and growth temperature. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Magnetic viscosity study in FePt/C granular films

International Nuclear Information System (INIS)

Huang, Y.; Butler, W.; Zhang, Y.; Hadjipanayis, G.C.; Weller, D.

2004-01-01

The magnetic viscosity of FePt/C granular thin films was studied in the temperature range from 2 to 300 K in order to examine the thermal stability of the nanoparticles. The magnetic viscosity coefficient (S max ) was found to decrease with temperature because of decreased thermal activation. At low temperatures, S max showed an almost linear dependence on temperature. However, S max does not extrapolate to zero but seems to have a finite value at cryogenic temperatures

Suprathermal viscosity of dense matter

International Nuclear Information System (INIS)

Alford, Mark; Mahmoodifar, Simin; Schwenzer, Kai

2010-01-01

Motivated by the existence of unstable modes of compact stars that eventually grow large, we study the bulk viscosity of dense matter, taking into account non-linear effects arising in the large amplitude regime, where the deviation μ Δ of the chemical potentials from chemical equilibrium fulfills μ Δ > or approx. T. We find that this supra-thermal bulk viscosity can provide a potential mechanism for saturating unstable modes in compact stars since the viscosity is strongly enhanced. Our study confirms previous results on strange quark matter and shows that the suprathermal enhancement is even stronger in the case of hadronic matter. We also comment on the competition of different weak channels and the presence of suprathermal effects in various color superconducting phases of dense quark matter.

Viscosity modification of high-oleic sunflower oil with polymeric additives for the design of new biolubricant formulations.

Science.gov (United States)

Quinchia, L A; Delgado, M A; Valencia, C; Franco, J M; Gallegos, C

2009-03-15

Although most common lubricants contain mineral or synthetic oils as basestocks, new environmental regulations are demanding environmentally friendly lubricants. In this sense, vegetable oils represent promising alternatives to mineral-based lubricants because of their high biodegradability, good lubricity, and low volatility. However, their poor thermooxidative stability and the small range of viscosity represent a clear disadvantage to be used as suitable biolubricants. The main objective of this work was to develop new environmentally friendly lubricant formulations with improved kinematic viscosity values and viscosity thermal susceptibility. With this aim, a high-oleic sunflower oil (HOSO) was blended with polymeric additives, such as ethylene vinyl acetate (EVA) and styrene-butadiene-styrene (SBS) copolymers, at different concentrations (0.5-5% w/w). Dynamic viscosity and density measurements were performed in a rotational rheometer and capillary densimeter, respectively, in a temperature range between 25 and 120 degrees C. An Arrhenius-like equation fits the evolution of viscosity with temperature fairly well. Both EVA and SBS copolymers may be satisfactorily used as additives to increase the viscosity of HOSO, thus improving the low viscosity values of this oil. HOSO viscosity increases with polymer concentration. Specifically, EVA/HOSO blends exhibit higher viscosity values, which are needed for applications such as lubrication of bearings and four-stroke engines. On the other hand, viscositythermal susceptibility of HOSO samples increases with EVA or SBS concentration.

Shear viscosities from Kubo formalism in a large-Nc Nambu-Jona-Lasinio model

International Nuclear Information System (INIS)

Lang, Robert Friedrich

2015-01-01

The quark-gluon plasma produced in heavy-ion collisions at RHIC and LHC is a hot and dense state of strongly correlated matter. It behaves like an almost-perfect fluid featuring a small ratio of shear viscosity to entropy density. In this thesis we calculate within a two-flavor Nambu-Jona-Lasinio model the shear viscosity as function of temperature and chemical potential. A new Kubo formula is developed, incorporating the full Dirac structure of the quark spectral function and avoiding commonly used on-shell approximations. Mesonic fluctuations occurring at Fock level provide the dominant dissipative process. The resulting parameter-free ratio is an overall decreasing function of temperature and chemical potential. In combination with hard-thermal-loop results we nd this ratio to feature a minimum slightly above the AdS/CFT benchmark.

Mechanochemically conjugated PMHS/nano-SiO 2 hybrid and subsequent optimum grafting density study

Science.gov (United States)

Lin, Jinbin; Chen, Hongling; Yuan, Yongbing; Ji, Yan

2011-08-01

In this paper, we reported the preparation of poly(methylhydrosiloxane) (PMHS)/SiO 2 hybrid particles by mechanochemical method based on high energy ball milling (HEBM). The obtained hybrid particles were characterized by Fourier transform infrared (FT-IR) spectroscopy, 29Si CP (cross-polarization) MAS NMR, viscosity measurement, particle size distribution, thermal analysis (TGA, DSC and DTG), static contact angle (CA), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). FT-IR and 29Si CP MAS NMR spectra indicate that PMHS is chemically anchored onto the surface of nano-SiO 2. Viscosity measurement, particle size distribution, FE-SEM and TEM demonstrate that an appropriate grafting density optimizes the dispersion of nanoparticles in poly(dimethylsiloxane) (PDMS) matrix, so lower viscosity can be achieved. Too high or too low grafting density may only achieve suboptimal and poor dispersions. The optimum grafting density of PMHS on nano-SiO 2 was determined by thermal analysis, with approximately 0.0531 PMHS/nm 2. Static contact angle measurement indicates that the water contact angle of hybrid particles is modulated by changing the grafting density of PMHS on nano-SiO 2. The CA value of PMHS/SiO 2 hybrid with optimum grafting density is 139.4°, and the highest CA value of PMHS/SiO 2 hybrid is approximately 158.2°.

The role of viscosity in TATB hot spot ignition

Science.gov (United States)

Fried, Laurence E.; Zepeda-Ruis, Luis; Howard, W. Michael; Najjar, Fady; Reaugh, John E.

2012-03-01

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.

Viscosity Control Experiment Feasibility Study

Energy Technology Data Exchange (ETDEWEB)

Morris, Heidi E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bradley, Paul Andrew [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2018-01-31

Turbulent mix has been invoked to explain many results in Inertial Confinement Fusion (ICF) and High Energy Density (HED) physics, such as reduced yield in capsule implosions. Many ICF capsule implosions exhibit interfacial instabilities seeded by the drive shock, but it is not clear that fully developed turbulence results from this. Many simulations use turbulent mix models to help match simulation results to data, but this is not appropriate if turbulence is not present. It would be useful to have an experiment where turbulent mixing could be turned on or off by design. The use of high-Z dopants to modify viscosity and the resulting influence on turbulence is considered here. A complicating factor is that the plasma in some implosions can become strongly coupled, which makes the Spitzer expression for viscosity invalid. We first consider equations that cover a broad parameter space in temperature and density to address regimes for various experimental applications. Next, a previous shock-tube and other ICF experiments that investigate viscosity or use doping to examine the effects on yield are reviewed. How viscosity and dopants play a role in capsule yield depends on the region and process under consideration. Experiments and simulations have been performed to study the effects of viscosity on both the hot spot and the fuel/ablator mix. Increases in yield have been seen for some designs, but not all. We then discuss the effect of adding krypton dopant to the gas region of a typical OMEGA and a 2-shock NIF implosion to determine approximately the effect of adding dopant on the computed Reynolds number. Recommendations for a path forward for possible experiments using high-Z dopants to affect viscosity and turbulence are made.

Calibration and Measurement of the Viscosity of DWPF Start-Up Glass

International Nuclear Information System (INIS)

Schumacher, R.F.

2001-01-01

The Harrop, High-Temperature Viscometer has been in operation at the Savannah River Technology Center (SRTC) for several years and has proven itself to be reasonably accurate and repeatable. This is particularly notable when taking into consideration the small amount of glass required to make the viscosity determination. The volume of glass required is only 2.60 cc or about 6 to 7 grams of glass depending on the glass density. This may be compared to the more traditional viscosity determinations, which generally require between 100 to 1000 grams of glass. Before starting the present investigation, the unit was re-aligned and the furnace thermal gradients measured. The viscometer was again calibrated with available NIST Standard Reference Material glasses (717a and 710a) and a spindle constant equation was determined. Standard DWPF Waste Compliance Glasses (Purex, HM, and Batch 1) were used to provide additional verification for the determinations at low temperature. The Harrop, High-Temperature Viscometer was then used to determine the viscosity of three random samples of ground and blended DWPF, Black, Start -Up Frit, which were obtained from Pacific Northwest National Laboratory (PNNL). The glasses were in powder form and required melting prior to the viscosity determination. The results from this evaluation will be compared to ''Round Robin'' measurements from other DOE laboratories and a number of commercial laboratories

Ultrasonic speed, densities and viscosities of xylitol in water and in aqueous tyrosine and phenylalanine solutions at different temperatures

Science.gov (United States)

Ali, A.; Bidhuri, P.; Uzair, S.

2014-07-01

Ultrasonic speed u, densities ρ and viscosities η of xylitol in water and in 0.001 m aqueous l-tyrosine (Tyr) and l-phenylalanine (Phe) have been measured at different temperatures. From the density and ultrasonic speed measurements apparent molar isentropic compression κ_{φ}, apparent molar isentropic compressions at infinite dilution κ_{{S,φ}}0 , experimental slope S K , hydration number n H , transfer partial molar isentropic compressibility Δ_{tr} κ_{{S,φ}}0 of xylitol from water to aqueous Tyr and Phe have been obtained. From the viscosity data, B-coefficient and B-coefficient of transfer Δ tr B of xylitol from water to aqueous Phe and Tyr at different temperatures have also been estimated. Gibbs free energies of activation of viscous flow per mole of solvent Δ μ 1 0# and per mole of solute Δ μ 2 0# have been calculated by using Feakins transition state theory for the studied systems. The calculated parameters have been interpreted in terms of solute-solute and solute-solvent interactions and hydration behavior of xylitol.

Viscosity of low-temperature substances at pressure

International Nuclear Information System (INIS)

Rudenko, N.S.; Slyusar', V.P.

1976-01-01

The review presents an analysis of data available on the viscosity coefficients of hydrogen, deuterohydrogen, deuterium, neon, argon, krypton, xenon, nitrogen and methane under pressure in the temperature range from triple points to 300 deg K. Averaged values of viscosity coefficients for all the substances listed above versus temperature, pressure and density are tabulated

Densities and viscosities of binary and ternary mixtures of cyclohexanone, 1,4-dioxane and isooctane from T = (288.15 to 313.15) K

International Nuclear Information System (INIS)

Rafiee, Hamid Reza; Ranjbar, Shahram; Poursalman, Fariborz

2012-01-01

Graphical abstract: For binary and ternary mixtures of the following liquids the densities and viscosities have been determined at several temperatures and over the entire range of composition. Also the Δη and excess molar volumes for binary mixtures determined and have been fitted to the Redlich–Kister equation. The interaction parameters, G 12 in the Grunberg–Nissan equation have been found to be negative for all binary mixtures which indicates decreasing the interaction between unlike molecules. Highlights: ► Experimental data for viscosity and density of binary and ternary mixtures reported. ► The considered solvents are Cyclohexanone, 1,4-Dioxane and Isooctane. ► Temperature ranges from 288.15 to 313.15 K and entire range of composition is considered. ► G 12 , in Grunberg–Nissan equation was negative in all binary mixtures at all temperatures. ► V E and Δη for binary mixtures have been fitted to Redlich–Kister equation. - Abstract: Densities and viscosities of binary and ternary mixtures of cyclohexanone, 1,4-dioxane and isooctane have been measured at temperatures from 288.15 K to 313.15 K and over the entire composition range, under atmospheric pressure. From these binary data, the excess molar volumes have been determined and then fitted to Redlich–Kister equation to determine the appropriate coefficients. This work also provides a test of the Grunberg and Nissan equation for correlation the dynamic viscosities of binary mixtures with mole fractions. The interaction parameters for this equation, G 12 were negative for all binary mixtures at different temperatures over entire range of composition which attributed to decreasing the strength of interaction between unlike molecules in mixture.

Paramagnetic ionic liquids for measurements of density using magnetic levitation.

Science.gov (United States)

Bwambok, David K; Thuo, Martin M; Atkinson, Manza B J; Mirica, Katherine A; Shapiro, Nathan D; Whitesides, George M

2013-09-03

Paramagnetic ionic liquids (PILs) provide new capabilities to measurements of density using magnetic levitation (MagLev). In a typical measurement, a diamagnetic object of unknown density is placed in a container containing a PIL. The container is placed between two magnets (typically NdFeB, oriented with like poles facing). The density of the diamagnetic object can be determined by measuring its position in the magnetic field along the vertical axis (levitation height, h), either as an absolute value or relative to internal standards of known density. For density measurements by MagLev, PILs have three advantages over solutions of paramagnetic salts in aqueous or organic solutions: (i) negligible vapor pressures; (ii) low melting points; (iii) high thermal stabilities. In addition, the densities, magnetic susceptibilities, glass transition temperatures, thermal decomposition temperatures, viscosities, and hydrophobicities of PILs can be tuned over broad ranges by choosing the cation-anion pair. The low melting points and high thermal stabilities of PILs provide large liquidus windows for density measurements. This paper demonstrates applications and advantages of PILs in density-based analyses using MagLev.

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.

Study of thermal and chemical effects on cellulase enzymes: Viscosity measurements

International Nuclear Information System (INIS)

Ghaouar, N.; Aschi, A.; Belbahri, L.; Trabelsi, S.; Gharbi, A.

2009-01-01

The behaviour of cellulase enzymes in phosphate saline buffer has been studied over a wide range of temperatures and enzyme concentrations by using viscosity measurements. To characterize the conformation change of cellulase versus temperature and chemical denaturants, such as guanidinium chloride (GdmCl) and urea, the information about the intrinsic viscosity and the hydrodynamic radius are necessary. The dependence of the intrinsic viscosity and the hydrodynamic radius in its random coil conformation on temperature and denaturant concentration were studied. Our results and discussions are limited to the dilute regime of concentration because of abnormalities in conformation observed in the very dilute regime due to the presence of capillary absorption effects.

Study of thermal and chemical effects on cellulase enzymes: Viscosity measurements

Energy Technology Data Exchange (ETDEWEB)

Ghaouar, N., E-mail: naoufel-ghaouar@lycos.co [Laboratoire de Physique de la Matiere Molle, Faculte des Sciences de Tunis, Campus Universitaire, 2092 (Tunisia); Institut National des Sciences Appliquees et de Technologie, INSAT, Centre Urbain Nord, BP. 676, Tunis (Tunisia); Aschi, A. [Laboratoire de Physique de la Matiere Molle, Faculte des Sciences de Tunis, Campus Universitaire, 2092 (Tunisia); Belbahri, L. [Agronomy Department, School of Engineering of Lullier, University of Applied Sciences of Western Switzerland, 150, Route de Presinge, 1254 Jussy (Switzerland); Trabelsi, S.; Gharbi, A. [Laboratoire de Physique de la Matiere Molle, Faculte des Sciences de Tunis, Campus Universitaire, 2092 (Tunisia)

2009-11-15

The behaviour of cellulase enzymes in phosphate saline buffer has been studied over a wide range of temperatures and enzyme concentrations by using viscosity measurements. To characterize the conformation change of cellulase versus temperature and chemical denaturants, such as guanidinium chloride (GdmCl) and urea, the information about the intrinsic viscosity and the hydrodynamic radius are necessary. The dependence of the intrinsic viscosity and the hydrodynamic radius in its random coil conformation on temperature and denaturant concentration were studied. Our results and discussions are limited to the dilute regime of concentration because of abnormalities in conformation observed in the very dilute regime due to the presence of capillary absorption effects.

Bulk and shear viscosities of hot and dense hadron gas

International Nuclear Information System (INIS)

Kadam, Guru Prakash; Mishra, Hiranmaya

2015-01-01

We estimate the bulk and the shear viscosity at finite temperature and baryon densities of hadronic matter within a hadron resonance gas model which includes a Hagedorn spectrum. The parameters of the Hagedorn spectrum are adjusted to fit recent lattice QCD simulations at finite chemical potential. For the estimation of the bulk viscosity we use low energy theorems of QCD for the energy momentum tensor correlators. For the shear viscosity coefficient, we estimate the same using molecular kinetic theory to relate the shear viscosity coefficient to average momentum of the hadrons in the hot and dense hadron gas. The bulk viscosity to entropy ratio increases with chemical potential and is related to the reduction of velocity of sound at nonzero chemical potential. The shear viscosity to entropy ratio on the other hand, shows a nontrivial behavior with the ratio decreasing with chemical potential for small temperatures but increasing with chemical potential at high temperatures and is related to decrease of entropy density with chemical potential at high temperature due to finite volume of the hadrons

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.

Density dependence of reactor performance with thermal confinement scalings

International Nuclear Information System (INIS)

Stotler, D.P.

1992-03-01

Energy confinement scalings for the thermal component of the plasma published thus far have a different dependence on plasma density and input power than do scalings for the total plasma energy. With such thermal scalings, reactor performance (measured by Q, the ratio of the fusion power to the sum of the ohmic and auxiliary input powers) worsens with increasing density. This dependence is the opposite of that found using scalings based on the total plasma energy, indicating that reactor operation concepts may need to be altered if this density dependence is confirmed in future research

Thermal flow regulator of refrigerant

International Nuclear Information System (INIS)

Dubinskij, S.I.; Savchenko, A.G.; Suplin, V.Z.

1988-01-01

A thermal flow regulator of refrigerant for helium flow-type temperature-controlled cryostats based on controlling the channel hydraulic resistance due to variation of the flow density and viscosity during liquid helium transformation into the gaseous state. Behind the regulator both two-phase flow and a heated gas can be produced. The regulator resolution is (7-15)x10 -4 l/mW of liquid helium

Investigating the influence of pressure and temperature on malaysian crude oil density and viscosity for improved recovery

International Nuclear Information System (INIS)

Zahoor, M.K.; Derahman, M.N.

2012-01-01

Malaysia has great potential as a crude oil or fossil fuel producing country. To increase oil production, behavior of Malaysian Crude Oil has been analyzed with reference to temperature and pressure variations. The effect of these parameters on crude oil density and viscosity has been observed, to select the methodology to be adopted for increases recovery by implementing enhanced oil recovery (EOR) project. Based on this study it has been decided to further explore the feasibility of increasing reservoir pressure. (author)

Metal hydrides based high energy density thermal battery

International Nuclear Information System (INIS)

Fang, Zhigang Zak; Zhou, Chengshang; Fan, Peng; Udell, Kent S.; Bowman, Robert C.; Vajo, John J.; Purewal, Justin J.; Kekelia, Bidzina

2015-01-01

Highlights: • The principle of the thermal battery using advanced metal hydrides was demonstrated. • The thermal battery used MgH 2 and TiMnV as a working pair. • High energy density can be achieved by the use of MgH 2 to store thermal energy. - Abstract: A concept of thermal battery based on advanced metal hydrides was studied for heating and cooling of cabins in electric vehicles. The system utilized a pair of thermodynamically matched metal hydrides as energy storage media. The pair of hydrides that was identified and developed was: (1) catalyzed MgH 2 as the high temperature hydride material, due to its high energy density and enhanced kinetics; and (2) TiV 0.62 Mn 1.5 alloy as the matching low temperature hydride. Further, a proof-of-concept prototype was built and tested, demonstrating the potential of the system as HVAC for transportation vehicles

Thermalization through parton transport

International Nuclear Information System (INIS)

Zhang Bin

2010-01-01

A radiative transport model is used to study kinetic equilibration during the early stage of a relativistic heavy ion collision. The parton system is found to be able to overcome expansion and move toward thermalization via parton collisions. Scaling behaviors show up in both the pressure anisotropy and the energy density evolutions. In particular, the pressure anisotropy evolution shows an approximate α s scaling when radiative processes are included. It approaches an asymptotic time evolution on a time scale of 1 to 2 fm/c. The energy density evolution shows an asymptotic time evolution that decreases slower than the ideal hydro evolution. These observations indicate that partial thermalization can be achieved and viscosity is important for the evolution during the early longitudinal expansion stage of a relativistic heavy ion collision.

Shear viscosity coefficient from microscopic models

International Nuclear Information System (INIS)

Muronga, Azwinndini

2004-01-01

The transport coefficient of shear viscosity is studied for a hadron matter through microscopic transport model, the ultrarelativistic 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 π,η,ω,ρ,φ 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 on the energy density. We do not include hadron strings as degrees of freedom so as to maintain detailed balance. Hence we do not get the saturation of temperature but this leads to longer equilibration times

Metal hydrides based high energy density thermal battery

Energy Technology Data Exchange (ETDEWEB)

Fang, Zhigang Zak, E-mail: zak.fang@utah.edu [Department of Metallurgical Engineering, The University of Utah, 135 South 1460 East, Room 412, Salt Lake City, UT 84112-0114 (United States); Zhou, Chengshang; Fan, Peng [Department of Metallurgical Engineering, The University of Utah, 135 South 1460 East, Room 412, Salt Lake City, UT 84112-0114 (United States); Udell, Kent S. [Department of Metallurgical Engineering, The University of Utah, 50 S. Central Campus Dr., Room 2110, Salt Lake City, UT 84112-0114 (United States); Bowman, Robert C. [Department of Metallurgical Engineering, The University of Utah, 135 South 1460 East, Room 412, Salt Lake City, UT 84112-0114 (United States); Vajo, John J.; Purewal, Justin J. [HRL Laboratories, LLC, 3011 Malibu Canyon Road, Malibu, CA 90265 (United States); Kekelia, Bidzina [Department of Metallurgical Engineering, The University of Utah, 50 S. Central Campus Dr., Room 2110, Salt Lake City, UT 84112-0114 (United States)

2015-10-05

Highlights: • The principle of the thermal battery using advanced metal hydrides was demonstrated. • The thermal battery used MgH{sub 2} and TiMnV as a working pair. • High energy density can be achieved by the use of MgH{sub 2} to store thermal energy. - Abstract: A concept of thermal battery based on advanced metal hydrides was studied for heating and cooling of cabins in electric vehicles. The system utilized a pair of thermodynamically matched metal hydrides as energy storage media. The pair of hydrides that was identified and developed was: (1) catalyzed MgH{sub 2} as the high temperature hydride material, due to its high energy density and enhanced kinetics; and (2) TiV{sub 0.62}Mn{sub 1.5} alloy as the matching low temperature hydride. Further, a proof-of-concept prototype was built and tested, demonstrating the potential of the system as HVAC for transportation vehicles.

Simultaneous viscosity and density measurement of small volumes of liquids using a vibrating microcantilever† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c6an02674e Click here for additional data file.

Science.gov (United States)

Payam, A. F.; Trewby, W.

2017-01-01

Many industrial and technological applications require precise determination of the viscosity and density of liquids. Such measurements can be time consuming and often require sampling substantial amounts of the liquid. These problems can partly be overcome with the use of microcantilevers but most existing methods depend on the specific geometry and properties of the cantilever, which renders simple, accurate measurement difficult. Here we present a new approach able to simultaneously quantify both the density and the viscosity of microliters of liquids. The method, based solely on the measurement of two characteristic frequencies of an immersed microcantilever, is completely independent of the choice of a cantilever. We derive analytical expressions for the liquid's density and viscosity and validate our approach with several simple liquids and different cantilevers. Application of our model to non-Newtonian fluids shows that the calculated viscosities are remarkably robust when compared to measurements obtained from a standard rheometer. However, the results become increasingly dependent on the cantilever geometry as the frequency-dependent nature of the liquid's viscosity becomes more significant. PMID:28352874

Thermally induced motion of marine sediments resulting from disposal of radioactive wastes

International Nuclear Information System (INIS)

Chavez, P.F.; Dawson, P.R.

1981-01-01

Coupled creep and heat transfer calculations have been performed to assess the sensitivity of heat load, viscosity, and canister density on the motion of waste canisters buried in marine sediments. Results indicate that no upward movement is predicted for heat loads remaining within the metallurgical and geochemical constraints placed on the temperature of sediments near the canister for the times analyzed. Upward movement of the canister is again not observed in calculations involving reasonable variations of the sediment viscosity and canister density. Maximum effective deviatoric stress levels due to thermally induced differential body forces are significantly less than the sediment's short term peak strength

Sensor for Viscosity and Shear Strength Measurement

International Nuclear Information System (INIS)

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

Effect of Al_2O_3 Nanoparticles Additives on the Density, Saturated Vapor Pressure, Surface Tension and Viscosity of Isopropyl Alcohol

Science.gov (United States)

Zhelezny, Vitaly; Geller, Vladimir; Semenyuk, Yury; Nikulin, Artem; Lukianov, Nikolai; Lozovsky, Taras; Shymchuk, Mykola

2018-03-01

This paper presents results of an experimental study of the density, saturated vapor pressure, surface tension and viscosity of Al_2O_3 nanoparticle colloidal solutions in isopropyl alcohol. Studies of the thermophysical properties of nanofluids were performed at various temperatures and concentrations of Al_2O_3 nanoparticles. The paper gives considerable attention to a turbidimetric analysis of the stability of nanofluid samples. Samples of nanofluids remained stable over the range of parameters of the experiments, ensuring the reliability of the thermophysical property data for the Al_2O_3 nanoparticle colloidal solutions in isopropyl alcohol. The studies show that the addition of Al_2O_3 nanoparticles leads to an increase of the density, saturated vapor pressure and viscosity, as well as a decrease for the surface tension of isopropyl alcohol. The information reported in this paper on the various thermophysical properties for the isopropyl alcohol/Al_2O_3 nanoparticle model system is useful for the development of thermodynamically consistent models for predicting properties of nanofluids and correct modeling of the heat exchange processes.

Measurement and modeling of density and viscosity of n-octanol-kerosene-phosphoric acid solutions in a temperature range 293.15-333.15 K

Science.gov (United States)

Ye, Changwen; Pei, Xiangjun; Liu, J. C.

2016-12-01

Densities and viscosities have been measured for the n-octanol + aviation kerosene (AK) + phosphoric acid (H3PO4) system with the mass fraction of H3PO4 in the range from w = 0 to 0.26 and in the temperature of 293.15-333.15 K. According to the experimental data, the measured viscosities were found well correlated with the temperature and mass fraction of H3PO4, which were fitted to regression equations. The result shows that the dilution effect of AK is obvious under the same temperature and mass fraction of H3PO4.

Viscosity and Analytical Differences between Raw Milk and UHT Milk of Czech Cows

Directory of Open Access Journals (Sweden)

Kumbár V.

2015-06-01

Full Text Available Viscosity and analytical differences in four milk samples from Czech cows were described. Three samples of UHT milk (0.5%, 1.5%, and 3.5% fat and one sample of raw milk from a Czech bio-farm were analyzed. The following analytical properties were observed: titratable acidity, fat content, dry matter content, and protein content. Titratable acidity and dry matter content decreased in dependence upon the increasing milk fat content. The protein content ranged 3.51-3.57 g per 100 g milk. The milk flow behaviour represented by density, dynamic and kinematic viscosity, as well as the dependence of the milk flow behaviour on temperature were investigated. These properties were measured using a digital densitometer and a rotary viscometer. Milk density was studied at temperatures ranging 0-60 °C and dynamic viscosity at 0-100 °C. With increasing temperature, the density and dynamic viscosity of the studied milk samples decreased. The temperature dependence of dynamic viscosity was manifested in all samples. Kinematic viscosity was calculated from experimental data. Furthermore, mathematical models using Power law and Gaussian fitting were constructed. Determination coefficients achieved high values (0.843-0.997.

Relating the baryon asymmetry to the thermal relic dark matter density

International Nuclear Information System (INIS)

McDonald, John

2011-01-01

We present a generic framework, baryomorphosis, which modifies the baryon asymmetry to be naturally of the order of a typical thermal relic weakly interacting massive particle (WIMP) density. We consider a simple scalar-based model to show how this is possible. This model introduces a sector in which a large initial baryon asymmetry is injected into particles ('annihilons'), φ B , φ-circumflex B , of mass ∼100 GeV-1 TeV. φ B φ-circumflex B annihilations convert the initial φ B , φ-circumflex B asymmetry to a final asymmetry with a thermal relic WIMP-like density. This subsequently decays to a conventional baryon asymmetry whose magnitude is naturally related to the density of thermal relic WIMP dark matter. In this way the two coincidences of baryons and dark matter, i.e. why their densities are similar to each other and why they are both similar to a WIMP thermal relic density (the 'WIMP miracle'), may be understood. The model may be tested by the production of annihilons at colliders.

Deep and wide gaps by super Earths in low-viscosity discs

Science.gov (United States)

Ginzburg, Sivan; Sari, Re'em

2018-06-01

Planets can open cavities (gaps) in the protoplanetary gaseous discs in which they are born by exerting gravitational torques. Viscosity counters these torques and limits the depletion of the gaps. We present a simple one-dimensional scheme to calculate the gas density profile inside gaps by balancing the gravitational and viscous torques. By generalizing the results of Goodman & Rafikov (2001), our scheme properly accounts for the propagation of angular momentum by density waves. This method allows us to easily study low-viscosity discs, which are challenging for full hydrodynamical simulations. We complement our numerical integration by analytical equations for the gap's steady-state depth and width as a function of the planet's to star's mass ratio μ, the gas disc's aspect ratio h, and its Shakura & Sunyaev viscosity parameter α. Specifically, we focus on low-mass planets (μ < μth ≡ h3) and identify a new low-viscosity regime, α < h(μ/μth)5, in which the classical analytical scaling relations are invalid. Equivalently, this low-viscosity regime applies to every gap that is depleted by more than a factor of (μth/μ)3 relative to the unperturbed density. We show that such gaps are significantly deeper and wider than previously thought, and consequently take a longer time to reach equilibrium.

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.

An ultrasonic instrument for measuring density and viscosity of tank waste

International Nuclear Information System (INIS)

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

1997-01-01

An estimated 381,000 m 3 /1.1 x 10 9 Ci of radioactive waste are stored in high-level waste tanks at the Hanford Savannah River, Idaho Nuclear Engineering and Environmental Laboratory, and West Valley facilities. This nuclear waste has created one of the most complex waste management and cleanup problems that face the United States. Release of radioactive materials into the environment from underground waste tanks requires immediate cleanup and waste retrieval. Hydraulic mobilization with mixer pumps will be used to retrieve waste slurries and salt cakes from storage tanks. To ensure that transport lines in the hydraulic system will not become plugged, the physical properties of the slurries must be monitored. Characterization of a slurry flow requires reliable measurement of slurry density, mass flow, viscosity, and volume percent of solids. Such measurements are preferably made with on-line nonintrusive sensors that can provide continuous real-time monitoring. With the support of the U.S. Department of Energy (DOE) Office of Environmental Management (EM-50), Argonne National Laboratory (ANL) is developing an ultrasonic instrument for in-line monitoring of physical properties of radioactive tank waste

Empty calories and phantom fullness: a randomized trial studying the relative effects of energy density and viscosity on gastric emptying determined by MRI and satiety.

Science.gov (United States)

Camps, Guido; Mars, Monica; de Graaf, Cees; Smeets, Paul Am

2016-07-01

Stomach fullness is a determinant of satiety. Although both the viscosity and energy content have been shown to delay gastric emptying, their relative importance is not well understood. We compared the relative effects of and interactions between the viscosity and energy density on gastric emptying and perceived satiety. A total of 15 healthy men [mean ± SD age: 22.6 ± 2.4 y; body mass index (in kg/m(2)): 22.6 ± 1.8] participated in an experiment with a randomized 2 × 2 crossover design. Participants received dairy-based shakes (500 mL; 50% carbohydrate, 20% protein, and 30% fat) that differed in viscosity (thin and thick) and energy density [100 kcal (corresponding to 0.2 kcal/mL) compared with 500 kcal (corresponding to 1 kcal/mL)]. After ingestion, participants entered an MRI scanner where abdominal scans and oral appetite ratings on a 100-point scale were obtained every 10 min until 90 min after ingestion. From the scans, gastric content volumes were determined. Overall, the gastric emptying half-time (GE t50) was 54.7 ± 3.8 min. The thin 100-kcal shake had the lowest GE t50 of 26.5 ± 3.0 min, followed by the thick 100-kcal shake with a GE t50 of 41 ± 3.9 min and the thin 500-kcal shake with a GE t50 of 69.5 ± 5.9 min, and the thick 500-kcal shake had the highest GE t50 of 81.9 ± 8.3 min. With respect to appetite, the thick 100-kcal shake led to higher fullness (58 points at 40 min) than the thin 500-kcal shake (48 points at 40 min). Our results show that increasing the viscosity is less effective than increasing the energy density in slowing gastric emptying. However, the viscosity is more important to increase the perceived fullness. These results underscore the lack of the satiating efficiency of empty calories in quickly ingested drinks such as sodas. The increase in perceived fullness that is due solely to the increased viscosity, which is a phenomenon that we refer to as phantom fullness, may be useful in lowering energy intake. This trial was

Determinação experimental da viscosidade e condutividade térmica de óleos vegetais Experimental measurements of viscosity and thermal conductivity of vegetable oils

Directory of Open Access Journals (Sweden)

Josiane Brock

2008-09-01

Full Text Available O presente trabalho tem por objetivo reportar valores experimentais de condutividade térmica e viscosidade dinâmica dos óleos vegetais refinados de soja, milho, girassol, algodão, canola, oliva e de farelo de arroz. As medidas de condutividade térmica foram realizadas em célula acoplada a um banho termostático no intervalo de temperatura de 20 a 70 °C, utilizando uma sonda de fio quente. Os resultados obtidos demonstram que para todos os óleos vegetais investigados a condutividade térmica possui fraca dependência com a temperatura, apresentando ligeiro decréscimo com o aumento desta variável. O método gravimétrico foi empregado para a medida da densidade dos óleos vegetais estudados à temperatura ambiente, não tendo sido verificada diferença significativa entre os valores encontrados. Para as medidas de viscosidade dos óleos vegetais foi utilizado um viscosímetro do tipo Brookfield, acoplado a um banho termostatizado com controle de temperatura. A partir dos resultados obtidos verificou-se que a viscosidade decresce acentuadamente com o aumento da temperatura para todos os óleos vegetais.This work reports experimental data of thermal conductivity and dynamic viscosity of the following refined vegetable oils: rice, soybean, corn oil, sunflower, cottonseed, and olive oil. Measurements of thermal properties were carried out in a cell coupled to a thermostatic bath in the temperature range of 20-70 °C, using a single-needle stainless steel sensor. It was experimentally observed that the thermal conductivity decreased slightly with increasing temperature for all samples investigated. The gravimetric method was employed for density data acquisition, and revealed no significant difference among the values obtained. The Brookfield apparatus was employed in measuring the dynamic viscosity and it was verified that a raise in temperature led to a sharp decrease for this property for all samples investigated.

The heat current density correlation function: sum rules and thermal conductivity

International Nuclear Information System (INIS)

Singh, Shaminder; Tankeshwar, K; Pathak, K N; Ranganathan, S

2006-01-01

Expressions for the second and fourth sum rules of the heat current density correlation function have been derived in an appropriate ensemble. The thermal conductivity of Lennard-Jones fluids has been calculated using these sum rules for the heat current density correlation function and the Gaussian form of the memory function. It is found that the results obtained for the thermal conductivity are in good agreement with the molecular dynamics simulation results over a wide range of densities and temperatures. Earlier results obtained using the energy current density correlation function are also discussed

The heat current density correlation function: sum rules and thermal conductivity

Energy Technology Data Exchange (ETDEWEB)

Singh, Shaminder [Department of Physics, Panjab University, Chandigarh-160 014 (India); Tankeshwar, K [Department of Physics, Panjab University, Chandigarh-160 014 (India); Pathak, K N [Department of Physics, Panjab University, Chandigarh-160 014 (India); Ranganathan, S [Department of Physics, Royal Military College, Kingston, ON, K7K 7B4 (Canada)

2006-02-01

Expressions for the second and fourth sum rules of the heat current density correlation function have been derived in an appropriate ensemble. The thermal conductivity of Lennard-Jones fluids has been calculated using these sum rules for the heat current density correlation function and the Gaussian form of the memory function. It is found that the results obtained for the thermal conductivity are in good agreement with the molecular dynamics simulation results over a wide range of densities and temperatures. Earlier results obtained using the energy current density correlation function are also discussed.

Reference Data for the Density, Viscosity, and Surface Tension of Liquid Al-Zn, Ag-Sn, Bi-Sn, Cu-Sn, and Sn-Zn Eutectic Alloys

Science.gov (United States)

Dobosz, Alexandra; Gancarz, Tomasz

2018-03-01

The data for the physicochemical properties viscosity, density, and surface tension obtained by different experimental techniques have been analyzed for liquid Al-Zn, Ag-Sn, Bi-Sn, Cu-Sn, and Sn-Zn eutectic alloys. All experimental data sets have been categorized and described by the year of publication, the technique used to obtain the data, the purity of the samples and their compositions, the quoted uncertainty, the number of data in the data set, the form of data, and the temperature range. The proposed standard deviations of liquid eutectic Al-Zn, Ag-Sn, Bi-Sn, Cu-Sn, and Sn-Zn alloys are 0.8%, 0.1%, 0.5%, 0.2%, and 0.1% for the density, 8.7%, 4.1%, 3.6%, 5.1%, and 4.0% for viscosity, and 1.0%, 0.5%, 0.3%, N/A, and 0.4% for surface tension, respectively, at a confidence level of 95%.

Caldera resurgence driven by magma viscosity contrasts.

Science.gov (United States)

Galetto, Federico; Acocella, Valerio; Caricchi, Luca

2017-11-24

Calderas are impressive volcanic depressions commonly produced by major eruptions. Equally impressive is the uplift of the caldera floor that may follow, dubbed caldera resurgence, resulting from magma accumulation and accompanied by minor eruptions. Why magma accumulates, driving resurgence instead of feeding large eruptions, is one of the least understood processes in volcanology. Here we use thermal and experimental models to define the conditions promoting resurgence. Thermal modelling suggests that a magma reservoir develops a growing transition zone with relatively low viscosity contrast with respect to any newly injected magma. Experiments show that this viscosity contrast provides a rheological barrier, impeding the propagation through dikes of the new injected magma, which stagnates and promotes resurgence. In explaining resurgence and its related features, we provide the theoretical background to account for the transition from magma eruption to accumulation, which is essential not only to develop resurgence, but also large magma reservoirs.

Density, refractive index, interfacial tension, and viscosity of ionic liquids [EMIM][EtSO4], [EMIM][NTf2], [EMIM][N(CN)2], and [OMA][NTf2] in dependence on temperature at atmospheric pressure.

Science.gov (United States)

Fröba, Andreas P; Kremer, Heiko; Leipertz, Alfred

2008-10-02

The density, refractive index, interfacial tension, and viscosity of ionic liquids (ILs) [EMIM][EtSO 4] (1-ethyl-3-methylimidazolium ethylsulfate), [EMIM][NTf 2] (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide), [EMIM][N(CN) 2] (1-ethyl-3-methylimidazolium dicyanimide), and [OMA][NTf 2] (trioctylmethylammonium bis(trifluoromethylsulfonyl)imide) were studied in dependence on temperature at atmospheric pressure both by conventional techniques and by surface light scattering (SLS). A vibrating tube densimeter was used for the measurement of density at temperatures from (273.15 to 363.15) K and the results have an expanded uncertainty ( k = 2) of +/-0.02%. Using an Abbe refractometer, the refractive index was measured for temperatures between (283.15 and 313.15) K with an expanded uncertainty ( k = 2) of about +/-0.0005. The interfacial tension was obtained from the pendant drop technique at a temperature of 293.15 K with an expanded uncertainty ( k = 2) of +/-1%. For higher and lower temperatures, the interfacial tension was estimated by an adequate prediction scheme based on the datum at 293.15 K and the temperature dependence of density. For the ILs studied within this work, at a first order approximation, the quantity directly accessible by the SLS technique was the ratio of surface tension to dynamic viscosity. By combining the experimental results of the SLS technique with density and interfacial tension from conventional techniques, the dynamic viscosity could be obtained for temperatures between (273.15 and 333.15) K with an estimated expanded uncertainty ( k = 2) of less than +/-3%. The measured density, refractive index, and viscosity are represented by interpolating expressions with differences between the experimental and calculated values that are comparable with but always smaller than the expanded uncertainties ( k = 2). Besides a comparison with the literature, the influence of structural variations on the thermophysical properties of the

Viscosity to entropy density ratio for non-extremal Gauss-Bonnet black holes coupled to Born-Infeld electrodynamics

Energy Technology Data Exchange (ETDEWEB)

Das, Saurav [Indian Institute of Science Education and Research Kolkata, Nadia (India); Gangopadhyay, Sunandan [Indian Institute of Science Education and Research Kolkata, Nadia (India); Inter University Centre for Astronomy and Astrophysics, Pune (India); Ghorai, Debabrata [S.N. Bose National Centre for Basic Sciences, Kolkata (India)

2017-09-15

The ratio of the shear viscosity to the entropy density (η/s) is calculated for non-extremal black holes in D dimensions with arbitrary forms of the matter Lagrangian for which the space-time metric takes a particular form. The result reduces to the standard expressions in 5 dimensions. The η/s ratio is then computed for Gauss-Bonnet black holes coupled to Born-Infeld electrodynamics in 5 dimensions. As a result we found corrections as regards the BI parameter and th result is analytically exact up to all orders in this parameter. The computations are then extended to D dimensions. (orig.)

Thermal Fluctuations in Smooth Dissipative Particle Dynamics simulation of mesoscopic thermal systems

Science.gov (United States)

Gatsonis, Nikolaos; Yang, Jun

2013-11-01

The SDPD-DV is implemented in our work for arbitrary 3D wall bounded geometries. The particle position and momentum equations are integrated with a velocity-Verlet algorithm and the entropy equation is integrated with a Runge-Kutta algorithm. Simulations of nitrogen gas are performed to evaluate the effects of timestep and particle scale on temperature, self-diffusion coefficient and shear viscosity. The hydrodynamic fluctuations in temperature, density, pressure and velocity from the SDPD-DV simulations are evaluated and compared with theoretical predictions. Steady planar thermal Couette flows are simulated and compared with analytical solutions. Simulations cover the hydrodynamic and mesocopic regime and show thermal fluctuations and their dependence on particle size.

Estimation of the viscosities of liquid binary alloys

Science.gov (United States)

Wu, Min; Su, Xiang-Yu

2018-01-01

As one of the most important physical and chemical properties, viscosity plays a critical role in physics and materials as a key parameter to quantitatively understanding the fluid transport process and reaction kinetics in metallurgical process design. Experimental and theoretical studies on liquid metals are problematic. Today, there are many empirical and semi-empirical models available with which to evaluate the viscosity of liquid metals and alloys. However, the parameter of mixed energy in these models is not easily determined, and most predictive models have been poorly applied. In the present study, a new thermodynamic parameter Δ G is proposed to predict liquid alloy viscosity. The prediction equation depends on basic physical and thermodynamic parameters, namely density, melting temperature, absolute atomic mass, electro-negativity, electron density, molar volume, Pauling radius, and mixing enthalpy. Our results show that the liquid alloy viscosity predicted using the proposed model is closely in line with the experimental values. In addition, if the component radius difference is greater than 0.03 nm at a certain temperature, the atomic size factor has a significant effect on the interaction of the binary liquid metal atoms. The proposed thermodynamic parameter Δ G also facilitates the study of other physical properties of liquid metals.

Density, speed of sound, viscosity and refractive index properties of aqueous solutions of vitamins B1.HCl and B6.HCl at temperatures (278.15, 288.15, and 298.15) K

International Nuclear Information System (INIS)

Dhondge, Sudhakar S.; Deshmukh, Dinesh W.; Paliwal, Lalitmohan J.

2013-01-01

Highlights: ► Study of aqueous solutions of vitamins B 1 .HCl and B 6 .HCl at different temperatures has been presented. ► These are important vitamins. ► Different interactions among solute and solvents have been investigated. ► The results are interpreted in terms of water structure making and breaking effects due to cations. -- Abstract: The experimental values of density (ρ), speed of sound (u), absolute viscosity (η) and refractive index (n D ) properties are reported for aqueous solutions of thiamine hydrochloride (vitamin B 1 .HCl) and pyridoxine hydrochloride (vitamin B 6 .HCl) within the concentration range (0.01 to 0.55) mol ⋅ kg −1 at three different temperatures, viz. T/K = 278.15, 288.15, and 298.15. Using experimental data, different derived parameters such as the apparent molar volume of solute (ϕ V ), isentropic compressibility of solution (β S ), apparent molar isentropic compressibility of solute (ϕ KS ) and relative viscosity of solution (η r ) have been computed. The limiting values of apparent molar volume (ϕ V 0 ) and apparent molar isentropic compressibility (ϕ KS 0 ) have been obtained. The limiting apparent molar expansivity (ϕ E 0 ) of solute, coefficient of thermal expansion (α ∗ ) and hydration numbers (n h ) of above vitamins in the aqueous medium have also been estimated. The experimental values of relative viscosity are used to calculate the Jones–Dole equation viscosity A and B coefficients for the hydrochlorides. The temperature coefficients of B i.e. (dB/dT) for these solutes have been used to study water structure making and breaking effects due to cations. Further, a discussion is made on the basis of solute–solute and solute–solvent interactions

Prediction of viscosities and surface tensions of fuels using a new corresponding states model

DEFF Research Database (Denmark)

Queimada, A.J.; Rolo, L.I.; Caco, A.I.

2006-01-01

While some properties of diesels are cheap, easy and fast to measure, such as densities, others such as surface tensions and viscosities are expensive and time consuming. A new approach that uses some basic information such as densities to predict viscosities and surface tensions is here proposed......) 2005 Elsevier Ltd. All rights reserved....

Early Thermal History of Rhea: The Role of Serpentinization and Liquid State Convection

Science.gov (United States)

Czechowski, Leszek; Łosiak, Anna

2016-12-01

Early thermal history of Rhea is investigated. The role of the following parameters of the model is investigated: time of beginning of accretion, tini, duration of accretion, tac, viscosity of ice close to the melting point, η0, activation energy in the formula for viscosity, E, thermal conductivity of silicate component, ksil, ammonia content, XNH3, and energy of serpentinization, cserp. We found that tini and tac are crucial for evolution. All other parameters are also important, but no dramatic differences are found for realistic values. The process of differentiation is also investigated. It is found that liquid state convection could delay the differentiation for hundreds of My. The results are confronted with observational data from Cassini spacecraft. It is possible that differentiation is fully completed but the density of formed core is close to the mean density. If this interpretation is correct, then Rhea could have accreted any time before 3-4 My after formation of CAI.

Crystallization, Microstructure, and Viscosity Evolutions in Lithium Aluminosilicate Glass-Ceramics

Directory of Open Access Journals (Sweden)

Qiang Fu

2016-11-01

Full Text Available Lithium aluminosilicate glass-ceramics have found widespread commercial success in areas such as consumer products, telescope mirrors, fireplace windows, etc. However, there is still much to learn regarding the fundamental mechanisms of crystallization, especially related to the evolution of viscosity as a function of the crystallization (ceramming process. In this study, the impact of phase assemblage and microstructure on the viscosity was investigated using high temperature X-ray diffraction (HTXRD, beam bending viscometry (BBV, and transmission electron microscopy (TEM. Results from this study provide a first direct observation of viscosity evolution as a function of ceramming time and temperature. Sharp viscosity increases due to phase separation, nucleation and phase transformation are noticed through BBV measurement. A near-net shape ceramming can be achieved in TiO2-containing compositions by keeping the glass at a high viscosity (> 109 Pa.s throughout the whole thermal treatment.

Viscosity overshoot in the start-up of uniaxial elongation of low density polyethylene melts

DEFF Research Database (Denmark)

Rasmussen, Henrik K.; Nielsen, Jens Kromann; Bach, Anders

2005-01-01

The transient uniaxial elongational viscosity of BASF Lupolen 1840D and 3020D melts has been measured on a filament stretch rheometer up to Hencky strains of 6-7. The elongational viscosity of both melts was measured at 130 degrees C within a broad range of elongational rates. At high elongation ...

Fission hindrance and nuclear viscosity

Indian Academy of Sciences (India)

is in exact conformity with all the previous measurements [7,10–13]. The CASCADE calculations (solid lines in figure 1) used in this first level of analysis do not include any viscosity or temperature-dependent nuclear level density parameter a. The γ and particle decay are calculated using the standard prescriptions as ...

Thermal Condensate Structure and Cosmological Energy Density of the Universe

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Antonio Capolupo

2016-01-01

Full Text Available The aim of this paper is to study thermal vacuum condensate for scalar and fermion fields. We analyze the thermal states at the temperature of the cosmic microwave background (CMB and we show that the vacuum expectation value of the energy momentum tensor density of photon fields reproduces the energy density and pressure of the CMB. We perform the computations in the formal framework of the Thermo Field Dynamics. We also consider the case of neutrinos and thermal states at the temperature of the neutrino cosmic background. Consistency with the estimated lower bound of the sum of the active neutrino masses is verified. In the boson sector, nontrivial contribution to the energy of the universe is given by particles of masses of the order of 10−4 eV compatible with the ones of the axion-like particles. The fractal self-similar structure of the thermal radiation is also discussed and related to the coherent structure of the thermal vacuum.

Plasma viscosity with mass transport in spherical inertial confinement fusion implosion simulations

Energy Technology Data Exchange (ETDEWEB)

Vold, E. L.; Molvig, K. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Joglekar, A. S. [University of Michigan, Ann Arbor, Michigan 48109 (United States); Ortega, M. I. [University of New Mexico, Albuquerque, New Mexico 87131 (United States); Moll, R. [University of California, Santa Cruz, California 95064 (United States); Fenn, D. [Florida State University, Tallahassee, Florida 32306 (United States)

2015-11-15

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 Lagrangian 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 reduces the need for artificial viscosity to maintain numerical stability in the Lagrangian formulation and also modifies the flux-limiting needed for electron thermal conduction.

Searching for perfect fluids: quantum viscosity in a universal Fermi gas

International Nuclear Information System (INIS)

Cao, C; Elliott, E; Wu, H; Thomas, J E

2011-01-01

We measure the shear viscosity in a two-component Fermi gas of atoms, tuned to a broad s-wave collisional (Feshbach) resonance. At resonance, the atoms strongly interact and exhibit universal behavior, where the equilibrium thermodynamic properties and transport coefficients are universal functions of density n and temperature T. We present a new calibration of the temperature as a function of global energy, which is directly measured from the cloud profiles. Using the calibration, the trap-averaged shear viscosity in units of ℎn is determined as a function of the reduced temperature at the trap center, from nearly the ground state to the unitary two-body regime. Low-temperature data are obtained from the damping rate of the radial breathing mode, whereas high-temperature data are obtained from hydrodynamic expansion measurements. We also show that the best fit to the high-temperature expansion data is obtained for a vanishing bulk viscosity. The measured trap-averaged entropy per particle and shear viscosity are used to estimate the ratio of shear viscosity to entropy density, which is compared with that conjectured for a perfect fluid.

Should you trust your heavy oil viscosity measurement?

Energy Technology Data Exchange (ETDEWEB)

Nelson, L.; Miller, K.; Almond, R. [Petrovera Resources Ltd., Edmonton, AB (Canada)

2003-07-01

For the last 60 years, the heavy oil and bitumen reservoirs from western Canada have been exploited with varying degrees of success. There are many factors that may effect heavy oil and bitumen production rates. Primary production rates, which vary greatly from field to field, were found to improve with the addition of steam. Viscosity is the single most valued criteria in predicting cold production response from a new field. It is also the criteria used to determine whether thermal process are needed to reduce oil viscosity, or whether horizontal or vertical wells should be used. This study examined why production forecasts based on oil viscosity alone have been poor. It is based on an extensive data collection project in the Elk Point area reservoir which has lower than expected and erratic cold production rates. Viscosity values from the same wells were found to vary by a factor of four or more. One of the objectives of this study was to encourage commercial labs to develop an industry-wide standard method of heavy oil sample cleaning and viscosity measurement. It is generally understood that viscosity increases with an increase in the concentration of asphaltenes, but there is little information to quantify the relationship. Some studies suggest that viscosity increases logarithmically with increasing asphaltenes. It was concluded that the prediction of the viscosity of heavy oils and bitumens is very empirical, but there are ways to improve data comparisons and evaluation by applying available information from other scientific fields. 23 refs., 5 tabs., 6 figs.

Density, dynamic viscosity, and derived properties of binary mixtures of methanol or ethanol with water, ethyl acetate, and methyl acetate at T (293.15, 298.15, and 303.15) K

Energy Technology Data Exchange (ETDEWEB)

Gonzalez, Begona; Calvar, Noelia; Gomez, Elena [Chemical Engineering Department, University of Vigo, 36200 Vigo (Spain); Dominguez, Angeles [Chemical Engineering Department, University of Vigo, 36200 Vigo (Spain)], E-mail: admguez@uvigo.es

2007-12-15

Densities and dynamic viscosities for methanol or ethanol with water, ethyl acetate, and methyl acetate at several temperatures T = (293.15, 298.15, and 303.15) K have been measured over the whole composition range and 0.1 MPa, along with the properties of the pure components. Excess molar volumes, viscosity deviations, and excess free energy of activation for the binary systems at the above-mentioned temperatures, were calculated and fitted to the Redlich-Kister equation to determine the fitting parameters and the root-mean-square deviations. UNIQUAC equation was used to correlate the experimental viscosity data. The UNIFAC-VISCO method and ASOG-VISCO method, based on contribution groups, were used to predict the dynamic viscosities of the binary mixtures.

Density, dynamic viscosity, and derived properties of binary mixtures of methanol or ethanol with water, ethyl acetate, and methyl acetate at T (293.15, 298.15, and 303.15) K

International Nuclear Information System (INIS)

Gonzalez, Begona; Calvar, Noelia; Gomez, Elena; Dominguez, Angeles

2007-01-01

Densities and dynamic viscosities for methanol or ethanol with water, ethyl acetate, and methyl acetate at several temperatures T = (293.15, 298.15, and 303.15) K have been measured over the whole composition range and 0.1 MPa, along with the properties of the pure components. Excess molar volumes, viscosity deviations, and excess free energy of activation for the binary systems at the above-mentioned temperatures, were calculated and fitted to the Redlich-Kister equation to determine the fitting parameters and the root-mean-square deviations. UNIQUAC equation was used to correlate the experimental viscosity data. The UNIFAC-VISCO method and ASOG-VISCO method, based on contribution groups, were used to predict the dynamic viscosities of the binary mixtures

Numerical investigation of magnetohydrodynamic slip flow of power-law nanofluid with temperature dependent viscosity and thermal conductivity over a permeable surface

Directory of Open Access Journals (Sweden)

Hussain Sajid

2017-12-01

Full Text Available In this paper, a numerical investigation is carried out to study the effect of temperature dependent viscosity and thermal conductivity on heat transfer and slip flow of electrically conducting non-Newtonian nanofluids. The power-law model is considered for water based nanofluids and a magnetic field is applied in the transverse direction to the flow. The governing partial differential equations(PDEs along with the slip boundary conditions are transformed into ordinary differential equations(ODEs using a similarity technique. The resulting ODEs are numerically solved by using fourth order Runge-Kutta and shooting methods. Numerical computations for the velocity and temperature profiles, the skin friction coefficient and the Nusselt number are presented in the form of graphs and tables. The velocity gradient at the boundary is highest for pseudoplastic fluids followed by Newtonian and then dilatant fluids. Increasing the viscosity of the nanofluid and the volume of nanoparticles reduces the rate of heat transfer and enhances the thickness of the momentum boundary layer. The increase in strength of the applied transverse magnetic field and suction velocity increases fluid motion and decreases the temperature distribution within the boundary layer. Increase in the slip velocity enhances the rate of heat transfer whereas thermal slip reduces the rate of heat transfer.

Shear viscosity and entropy of a pion gas

Energy Technology Data Exchange (ETDEWEB)

Rose, Jean-Bernard; Oliinychenko, Dmytro; Schaefer, Anna; Petersen, Hannah [FIAS, Goethe University, Frankfurt (Germany)

2016-07-01

A model of microscopic non-equilibrium dynamics for classical point particles is used to calculate the transport coefficients of dense hadronic matter. Specifically, the shear viscosity to entropy density ratio is investigated, and the temperature dependence between 100 MeV and 300 MeV is explored. Calculations are made at corresponding particle densities going from 0.01 to 0.34 in a pion box simulating infinite matter. The results for the entropy and shear viscosity are then compared to analytic estimates. In addition, massless particles as well as ρ-meson resonance excitations are included. This will be the starting point for the calculation of more transport coefficients as functions of T and μ{sub B}; expanding systems could also be considered.

A new model for the accurate calculation of natural gas viscosity

OpenAIRE

Xiaohong Yang; Shunxi Zhang; Weiling Zhu

2017-01-01

Viscosity of natural gas is a basic and important parameter, of theoretical and practical significance in the domain of natural gas recovery, transmission and processing. In order to obtain the accurate viscosity data efficiently at a low cost, a new model and its corresponding functional relation are derived on the basis of the relationship among viscosity, temperature and density derived from the kinetic theory of gases. After the model parameters were optimized using a lot of experimental ...

Propagation of sound wave in high density deuterium at high temperatures

International Nuclear Information System (INIS)

Inoue, Kazuko; Ariyasu, Tomio

1986-01-01

The velocity and the attenuation constant of sound wave have been calculated for high density (10 24 ∼ 10 27 /cm 3 ) deuterium at high temperatures (10 -1 ∼ 10 4 eV). This calculation was made to understand the fuel properties in inertial confinement fusion and to obtain the basic data for pellet design. The isentropic sound wave which propagates in deuterium in plasma state at temperature T i = T e , is dealt with. The velocity is derived using the modulus of bulk elasticity of the whole system and the modulus of shear elasticity due to ion-ion interaction. For the calculation of attenuation constant, the bulk and shear viscosity due to ion-ion interaction, the shear viscosity of free electron gas, and the thermal conductivity due to free electrons are considered. The condition of frequency for the existence of such isentropic sound wave is discussed. The possibility of penetration into the fuel pellet in inertial confinement fusion is also discussed. The followings have been found: (1) The sound velocity is determined mainly from the bulk elasticity. The contribution of the shear elasticity is small. The velocity ranges from 2.8 x 10 6 to 1.5 x 10 8 cm/s in the above mentioned temperature and density regions. (2) The coefficient of attenuation constant with respect to ω 2 /2ρu 3 plotted versus temperature with the parameter of density shows a minimum. At temperatures below this minimum, the attenuation comes mainly from the bulk viscosity due to ion-ion interaction and the shear viscosity due to free electron gas. At temperatures above this minimum, the sound is attenuated mainly by the thermal conductivity due to electrons. (3) The condition for the existence of such adiabatic sound wave, is satisfied with the frequency less than 10 10 Hz. But, as for the pellet design, the wave length of sound with frequency less than 10 10 Hz is longer than the diameter of pellet when compressed highly. (author)

Effect of tellurium on viscosity and liquid structure of GaSb melts

Energy Technology Data Exchange (ETDEWEB)

Ji Leilei [School of Material Science and Engineering, Jinan University, Jinan 250022 (China); Geng Haoran [School of Material Science and Engineering, Jinan University, Jinan 250022 (China)], E-mail: mse_genghr@ujn.edu.cn; Sun Chunjing [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Teng Xinying; Liu Yamei [School of Material Science and Engineering, Jinan University, Jinan 250022 (China)

2008-04-03

The behavior of GaSb melt with tellurium addition was investigated using viscometer and differential scanning calorimetry (DSC). Normally, the viscosity of all melts measured decreased with the increasing temperature. However, anomalous transition points were observed in the temperature dependence of viscosity for Ga-Sb-Te system. Corresponded with the abnormal points on the viscosity-temperature curves, there were thermal effect peaks on the DSC curves. Furthermore, viscous activation energy and flow units of these melts and their structural features were discussed in this paper.

Effect of combined treatments on viscosity of whey dispersions

International Nuclear Information System (INIS)

Camillo, A.; Sabato, S.F.

2004-01-01

Whey proteins, enriched protein fractions from milk, are of great interest as ingredients due to nutritional value associated with its functional properties. These proteins could have their structural properties improved when some treatments are applied, such as thermal and gamma irradiation or when some compounds are added. The current work aimed to study the viscometer behavior of whey dispersions submitted to two different combined treatments: (1) thermal plus irradiation and (2) thermal plus vacuum and N 2 plus irradiation. Dispersions of whey protein in water (5% and 8% protein (w/v) base) and containing proteins and glycerol at ratios 1:1 and 2:1 (protein:glycerol) were submitted to both combined treatments. The irradiation doses were 0, 5, 15 and 25 kGy. The viscosity of the two combined treatments and for four levels of absorbed doses is presented and the combined effects are discussed. The thermal treatment combined with gamma irradiation contributed to increase the viscosity as irradiation doses increases for both (5% and 8%) concentrations of proteins (p<0.05). For protein and glycerol solutions, the irradiation dose seemed to result in a slightly increase. The vacuum applied before the irradiation showed a small contribution

Effect of combined treatments on viscosity of whey dispersions

Energy Technology Data Exchange (ETDEWEB)

Camillo, A.; Sabato, S.F. E-mail: sfsabato@ipen.br

2004-10-01

Whey proteins, enriched protein fractions from milk, are of great interest as ingredients due to nutritional value associated with its functional properties. These proteins could have their structural properties improved when some treatments are applied, such as thermal and gamma irradiation or when some compounds are added. The current work aimed to study the viscometer behavior of whey dispersions submitted to two different combined treatments: (1) thermal plus irradiation and (2) thermal plus vacuum and N{sub 2} plus irradiation. Dispersions of whey protein in water (5% and 8% protein (w/v) base) and containing proteins and glycerol at ratios 1:1 and 2:1 (protein:glycerol) were submitted to both combined treatments. The irradiation doses were 0, 5, 15 and 25 kGy. The viscosity of the two combined treatments and for four levels of absorbed doses is presented and the combined effects are discussed. The thermal treatment combined with gamma irradiation contributed to increase the viscosity as irradiation doses increases for both (5% and 8%) concentrations of proteins (p<0.05). For protein and glycerol solutions, the irradiation dose seemed to result in a slightly increase. The vacuum applied before the irradiation showed a small contribution.

Variable viscosity and thermal conductivity effects on MHD flow and heat transfer in viscoelastic fluid over a stretching sheet

International Nuclear Information System (INIS)

Salem, Ahmed M.

2007-01-01

The problem of flow and heat transfer of an electrically conducting viscoelastic fluid over a continuously stretching sheet in the presence of a uniform magnetic field is analyzed for the case of power-law variation in the sheet temperature. The fluid viscosity and thermal conductivity are assumed to vary as a function of temperature. The basic equations comprising the balance laws of mass, linear momentum, and energy modified to include the electromagnetic force effect, the viscous dissipation, internal heat generation or absorption and work due to deformation are solved numerically

Viscosities and densities of systems involved in the deterpenation of essential oils by liquid-liquid extraction: New UNIFAC-VISCO parameters

International Nuclear Information System (INIS)

Florido, Priscila M.; Andrade, Ivana M.G.; Capellini, Maria C.; Carvalho, Fernanda H.; Aracava, Keila K.; Koshima, Cristina C.; Rodrigues, Christianne E.C.; Gonçalves, Cintia B.

2014-01-01

Graphical abstract: - Highlights: • Physical properties of systems from deterpenation of essential oils were measured. • Viscosities were used to get new interaction parameters for the UNIFAC-VISCO model. • Parameters were optimized using a genetic algorithm. • A global average relative deviation of 0.68% was obtained considering all systems. • New parameters also presented a good predictive capability, with a ARD of 1.83%. - Abstract: This work reports viscosities and densities, at T = 298.15 K, of the phases formed after deterpenation of bergamot, lemon and mint essential oils, by (liquid + liquid) extraction (LLE). Samples of mixtures containing the main components of each essential oil (terpenes and oxygenated compounds), plus ethanol and water, were obtained from studies of phase equilibrium performed previously by our research group. Experimental viscosities were also correlated to the UNIFAC VISCO model, based on the group contribution method. Correlations were accomplished using two approaches: in the first one, functional groups already described by previous studies in the literature and new ones obtained in this work were considered, providing a global average relative deviation (ARD) equal to 1.70%; in a second approach, all functional groups were fitted to our experimental data, which provided a global average relative deviation equal to 0.68%. The predictive capability of the UNIFAC-VISCO were tested for systems involved in the deterpenation of eucalyptus essential oil, giving ARD values of (3.56 and 1.83)%, for parameters from first and second approach, respectively. These results indicate that, for more accurate calculation of viscosities, it is important to consider the particularities and the complexity of each system

3D Suspended Polymeric Microfluidics (SPMF3 with Flow Orthogonal to Bending (FOB for Fluid Analysis through Kinematic Viscosity

Directory of Open Access Journals (Sweden)

Mostapha Marzban

2017-10-01

Full Text Available Measuring of fluid properties such as dynamic viscosity and density has tremendous potential for various applications from physical to biological to chemical sensing. However, it is almost impossible to affect only one of these properties, as dynamic viscosity and density are coupled. Hence, this paper proposes kinematic viscosity as a comprehensive parameter which can be used to study the effect of fluid properties applicable to various fluids from Newtonian fluids, such as water, to non-Newtonian fluids, such as blood. This paper also proposes an ideal microplatform, namely polymeric suspended microfluidics (SPMF3, with flow plane orthogonal to the bending plane of the structure, along with tested results of various fluids covering a wide range of engineering applications. Kinematic viscosity, also called momentum diffusivity, considers changes in both fluid intermolecular forces and molecular inertia that define dynamic viscosity and fluid density, respectively. In this study a 3D suspended polymeric microfluidic system (SPMF3 was employed to detect changes in fluid parameters such as dynamic viscosity and density during fluid processes. Using this innovative design along with theoretical and experimental results, it is shown that, in fluids, the variations of fluid density and dynamic viscosity are not easily comprehensible due to their interconnectivity. Since any change in a fluid will affect both density and dynamic viscosity, measuring both of them is necessary to identify the fluid or process status. Finally, changes in fluid properties were analyzed using simulation and experiments. The experimental results with salt-DI water solution and milk with different fat concentrations as a colloidal fluid show that kinematic viscosity is a comprehensive parameter that can identify the fluids in a unique way using the proposed microplatform.

Magnetic viscosity and coercivity mechanisms in sintered and melt spun NdFeB

International Nuclear Information System (INIS)

Street, R.; Bingham, D.; Day, R.K.; Dunlop, J.B.

1988-01-01

Magnetic viscosity parameters kT/q(=Sv) of sintered and melt spun NdFeB vary with internal field. During initial magnetization of thermally demagnetized specimens signifiant viscosity occurs with melt spun NdFeB but is negligible with sintered NdFeB. Differences in mechanisms of magnetization account for this behaviour

High Density Thermal Energy Storage with Supercritical Fluids

Science.gov (United States)

Ganapathi, Gani B.; Wirz, Richard

2012-01-01

A novel approach to storing thermal energy with supercritical fluids is being investigated, which if successful, promises to transform the way thermal energy is captured and utilized. The use of supercritical fluids allows cost-affordable high-density storage with a combination of latent heat and sensible heat in the two-phase as well as the supercritical state. This technology will enhance penetration of several thermal power generation applications and high temperature water for commercial use if the overall cost of the technology can be demonstrated to be lower than the current state-of-the-art molten salt using sodium nitrate and potassium nitrate eutectic mixtures.

Effect of soft mode on shear viscosity of quark matter

International Nuclear Information System (INIS)

Fukutome, Takahiko; Iwasaki, Masaharu

2008-01-01

We calculate the shear viscosity of quark matter at finite temperature and density. If we assume that the quark interacts with the soft mode, which is a collective mode of a quark-antiquark pair, the self-energy of the quark is calculated by quasi-particle random phase approximation. It is shown that its imaginary part is large and its mean free path is short. With the use of the Kubo formula, the shear viscosity of quark matter decreases. The Reynolds number of quark matter is estimated to be about 10. As temperature increases, shear viscosity increases gradually for T>200 MeV. Moreover it is shown that the shear viscosity also increases with the chemical potential for μ>200 MeV. (author)

Electrical conductivity and viscosity of borosilicate glasses and melts

DEFF Research Database (Denmark)

Ehrt, Doris; Keding, Ralf

2009-01-01

, 0 to 62·5 mol% B2O3, and 25 to 85 mol% SiO2. The glass samples were characterised by different methods. Refractive indices, density and thermal expansion were measured. Phase separation effects were investigated by electron microscopy. The electrical conductivity of glasses and melts were determined......Simple sodium borosilicate and silicate glasses were melted on a very large scale (35 l Pt crucible) to prepare model glasses of optical quality in order to investigate various properties depending on their structure. The composition of the glass samples varied in a wide range: 3 to 33·3 mol% Na2O...... by impedance measurements in a wide temperature range (250 to 1450°C). The activation energies were calculated by Arrhenius plots in various temperature regions: below the glass transition temperature, Tg, above the melting point, Tl, and between Tg and Tl. Viscosity measurements were carried out...

In Situ Evaluation of Density, Viscosity and Thickness of Adsorbed Soft Layers by Combined Surface Acoustic Wave and Surface Plasmon Resonance

OpenAIRE

Francis, L.; Friedt, J. -M.; Zhou, C.; Bertrand, P.

2003-01-01

We show the theoretical and experimental combination of acoustic and optical methods for the in situ quantitative evaluation of the density, the viscosity and the thickness of soft layers adsorbed on chemically tailored metal surfaces. For the highest sensitivity and an operation in liquids, a Love mode surface acoustic wave (SAW) sensor with a hydrophobized gold coated sensing area is the acoustic method, while surface plasmon resonance (SPR) on the same gold surface as the optical method is...

Navier-Stokes hydrodynamics of thermal collapse in a freely cooling granular gas.

Science.gov (United States)

Kolvin, Itamar; Livne, Eli; Meerson, Baruch

2010-08-01

We show that, in dimension higher than one, heat diffusion and viscosity cannot arrest thermal collapse in a freely evolving dilute granular gas, even in the absence of gravity. Thermal collapse involves a finite-time blowup of the gas density. It was predicted earlier in ideal, Euler hydrodynamics of dilute granular gases in the absence of gravity, and in nonideal, Navier-Stokes granular hydrodynamics in the presence of gravity. We determine, analytically and numerically, the dynamic scaling laws that characterize the gas flow close to collapse. We also investigate bifurcations of a freely evolving dilute granular gas in circular and wedge-shaped containers. Our results imply that, in general, thermal collapse can only be arrested when the gas density becomes comparable with the close-packing density of grains. This provides a natural explanation to the formation of densely packed clusters of particles in a variety of initially dilute granular flows.

Time Dependent and Steady Uni-axial Elongational Viscosity

DEFF Research Database (Denmark)

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

2005-01-01

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

Bulk viscosity, interaction and the viability of phantom solutions

Energy Technology Data Exchange (ETDEWEB)

Leyva, Yoelsy; Sepulveda, Mirko [Universidad de Tarapaca, Departamento de Fisica, Facultad de Ciencias, Arica (Chile)

2017-06-15

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 interaction term, belongs to the quintessence region. In the latter case, we find bounds on the interaction parameter compatible with latest observational data. (orig.)

A facile way to prepare CuS-oil nanofluids with enhanced thermal conductivity and appropriate viscosity

Energy Technology Data Exchange (ETDEWEB)

Qin, Ji-Hua; Liu, Zhao-Qing; Li, Nan, E-mail: nanli@gzhu.edu.cn; Chen, Yi-Bo; Wang, Dong-Yao [Guangzhou University, School of Chemistry and Chemical Engineering/Guangzhou Key Laboratory for Environmentally Functional Materials and Technology (China)

2017-02-15

The nanofluid as a pivotal role in heat transfer system has attracted more and more attention. Herein, the stearic acid-modified CuS (SA-CuS) nanoparticles with a uniform diameter of 60 nm were synthesized successfully by a facile two-phase approach. Accordingly, the CuS-oil nanofluids, with SA-CuS concentrations ranging from 0.01 to 0.04 vol%, were prepared by a one-step method in the heat transfer oil. These CuS-oil nanofluids exhibit good stability and considerable enhanced thermal conductivity. The improvement is even up to 20.5% with a volume fraction of 0.04 vol% at 30 °C. Furthermore, the effect of volume fraction and temperature on the viscosity of the nanofluids was also systematically investigated.

PVT characterization and viscosity modeling and prediction of crude oils

DEFF Research Database (Denmark)

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

2004-01-01

In previous works, the general, one-parameter friction theory (f-theory), models have been applied to the accurate viscosity modeling of reservoir fluids. As a base, the f-theory approach requires a compositional characterization procedure for the application of an equation of state (EOS), in most...... pressure, is also presented. The combination of the mass characterization scheme presented in this work and the f-theory, can also deliver accurate viscosity modeling results. Additionally, depending on how extensive the compositional characterization is, the approach,presented in this work may also...... deliver accurate viscosity predictions. The modeling approach presented in this work can deliver accurate viscosity and density modeling and prediction results over wide ranges of reservoir conditions, including the compositional changes induced by recovery processes such as gas injection....

Synthesis, spectroscopic characterization and acoustic, volumetric, transport and thermal properties of hydroxyl ammonium based ionic liquids

International Nuclear Information System (INIS)

Losetty, Venkatramana; Chennuri, Bharath Kumar; Gardas, Ramesh L.

2016-01-01

Graphical abstract: Density, ρ (■) in kg · m"−"3, speed of sound, u (●) in m · s"−"1, dynamic viscosity, η (▴) in mPa · s, electrical conductivity, σ (♦) in S · cm"−"1of [BHEA][TFA] as the function of temperature and at 0.1 MPa pressure. - Highlights: • N-butyl-(N-hydroxyethyl) ammonium based protic ionic liquids (PILs) were synthesized. • Density, speed of sound, electrical conductivity and viscosity were measured for studied PILs. • Transport property data were fitted to Vogel–Tammann–Fulcher (VTF) equation. • FT-IR spectrum was helpful to explain the hydrogen bonding between ions. • Measured and derived properties were analyzed in terms of chemical structure of PILs. - Abstract: In the present work, solvent-free synthesis of two hydroxyethyl ammonium-based ionic liquids (ILs) at room temperature was carried out namely, N-butyl-(N-hydroxyethyl) ammonium trifluoroacetate ([BHEA][TFA]) and N-butyl-(N-hydroxyethyl) ammonium nitrate ([BHEA][NO_3]). The synthesized ionic liquids were characterized by various spectroscopic techniques such as "1H-NMR, "1"3C-NMR and FTIR. Furthermore, density (ρ), speed of sound (u), electrical conductivity (σ) and viscosity (η) have been measured within the temperature range from T = (303.15 to 343.15) K and at 0.1 MPa pressure. The measured density and viscosity values were fitted to the linear and Vogel–Tammann–Fulcher (VTF) equation, respectively. The temperature dependence conductivity of the measured ILs was fitted to a similar equation type of viscosity (VTF). Furthermore, the refractive index was measured at T = 303.15 K, in turn molar refraction (R_m) and free volume (f_V) were calculated using the Lorentz–Lorenz equation. The thermodynamic properties such as thermal expansion coefficient (α), isentropic compressibility (β_S) and intermolecular free length (L_f) were calculated by using the experimental values of density and speed of sound. The thermal decomposition temperature (T

Thermal Conductivity of Human Bone in Cryoprobe Freezing as Related to Density.

Science.gov (United States)

Walker, Kyle E; Baldini, Todd; Lindeque, Bennie G

2017-03-01

Cryoprobes create localized cell destruction through freezing. Bone is resistant to temperature flow but is susceptible to freezing necrosis at warmer temperatures than tumor cells. Few studies have determined the thermal conductivity of human bone. No studies have examined conductivity as related to density. The study goal was to examine thermal conductivity in human bone while comparing differences between cancellous and cortical bone. An additional goal was to establish a relationship between bone density and thermal conductivity. Six knee joints from 5 cadavers were obtained. The epiphyseal region was sliced in half coronally prior to inserting an argon-circulating cryoprobe directed away from the joint line. Thermistor thermometers were placed perpendicularly at measured increments, and the freezing cycle was recorded until steady-state conditions were achieved. For 2 cortical samples, the probe was placed intramedullary in metaphyseal samples and measurements were performed radially from the central axis of each sample. Conductivity was calculated using Fournier's Law and then plotted against measured density of each sample. Across samples, density of cancellous bone ranged from 0.86 to 1.38 g/mL and average thermal conductivity ranged between 0.404 and 0.55 W/mK. Comparatively, cortical bone had a density of 1.70 to 1.86 g/mL and thermal conductivity of 0.0742 to 0.109 W/mK. A strong 2-degree polynomial correlation was seen (R 2 =0.8226, P<.001). Bone is highly resistant to temperature flow. This resistance varies and inversely correlates strongly with density. This information is clinically relevant to maximize tumor ablation while minimizing morbidity through unnecessary bone loss and damage to surrounding structures. [Orthopedics. 2017; 40(2):90-94.]. Copyright 2016, SLACK Incorporated.

Viscosities in the Gluon-Plasma within a Quasiparticle Model

CERN Document Server

Bluhm, M; Redlich, K

2009-01-01

A phenomenological quasiparticle model, featuring dynamically generated self-energies of excitation modes, successfully describes lattice QCD results relevant for the QCD equation of state and related quantities both at zero and non-zero net baryon density. Here, this model is extended to study bulk and shear viscosities of the gluon-plasma within an effective kinetic theory approach. In this way, the compatibility of the employed quasiparticle ansatz with the apparent low viscosities of the strongly coupled deconfined gluonic medium is shown.

Azobenzene-functionalized carbon nanotubes as high-energy density solar thermal fuels.

Science.gov (United States)

Kolpak, Alexie M; Grossman, Jeffrey C

2011-08-10

Solar thermal fuels, which reversibly store solar energy in molecular bonds, are a tantalizing prospect for clean, renewable, and transportable energy conversion/storage. However, large-scale adoption requires enhanced energy storage capacity and thermal stability. Here we present a novel solar thermal fuel, composed of azobenzene-functionalized carbon nanotubes, with the volumetric energy density of Li-ion batteries. Our work also demonstrates that the inclusion of nanoscale templates is an effective strategy for design of highly cyclable, thermally stable, and energy-dense solar thermal fuels.

On Lateral Viscosity Contrast in the Mantle and the Rheology of Low-Frequency Geodynamics

Science.gov (United States)

Ivins, Erik R.; Sammis, Charles G.

1995-01-01

Mantle-wide heterogeneity is largely controlled by deeply penetrating thermal convective currents. These thermal currents are likely to produce significant lateral variation in rheology, and this can profoundly influence overall material behaviour. How thermally related lateral viscosity variations impact models of glacio-isostatic and tidal deformation is largely unknown. An important step towards model improvement is to quantify, or bound, the actual viscosity variations that characterize the mantle. Simple scaling of viscosity to shear-wave velocity fluctuations yields map-views of long- wavelength viscosity variation. These give a general quantitative description and aid in estimating the depth dependence of rheological heterogeneity throughout the mantle. The upper mantle is probably characterized by two to four orders of magnitude variation (peak-to-peak). Discrepant time-scales for rebounding Holocene shorelines of Hudson Bay and southern Iceland are consistent with this characterization. Results are given in terms of a local average viscosity ratio, (Delta)eta(bar)(sub i), of volumetric concentration, phi(sub i). For the upper mantle deeper than 340 km the following reasonable limits are estimated for (delta)eta(bar) approx. equal 10(exp -2): 0.01 less than or equal to phi less than or equal to 0.15. A spectrum of ratios (Delta)eta(bar)(sub i) less than 0.1 at concentration level eta(sub i) approx. equal 10(exp -6) - 10(exp -1) in the lower mantle implies a spectrum of shorter time-scale deformational response modes for second-degree spherical harmonic deformations of the Earth. Although highly uncertain, this spectrum of spatial variation allows a purely Maxwellian viscoelastic rheology simultaneously to explain all solid tidal dispersion phenomena and long-term rebound-related mantle viscosity. Composite theory of multiphase viscoelastic media is used to demonstrate this effect.

Divergent trend in density versus viscosity of ionic liquid/water mixtures: a molecular view from guanidinium ionic liquids.

Science.gov (United States)

Singh, Akhil Pratap; Gardas, Ramesh L; Senapati, Sanjib

2015-10-14

Ionic liquids (ILs) have shown great potential in the dissolution and stability of biomolecules when a low-to-moderate quantity of water is added. Hence, determining the thermophysical properties and understanding these novel mixtures at the molecular level are of both fundamental and practical importance. In this context, here we report the synthesis of two nontoxic guanidinium cation based ILs, tetramethylguanidinium benzoate [TMG][BEN] and tetramethylguanidinium salicylate [TMG][SAL], and present a detailed comparison of their thermophysical properties in the presence of water. The results show that the [TMG][SAL]/water mixtures have higher density and higher apparent molar volume, but a lower viscosity and higher compressibility than the [TNG][BEN]/water mixtures. The measured viscosity and compressibility data are explained from ab initio quantum mechanical calculations and liquid-phase molecular dynamics simulations, where salicylate anions of denser [TMG][SAL]/water were found to exist as isolated ions due to intramolecular H-bonding. On the contrary, intermolecular H-bonding among the benzoate anions and their strong tendency to form an extended H-bonding network with water made [TMG][BEN]/water solutions more viscous and less compressible. This study shows the importance of probing these emerging solvents at the molecular-to-atomic level, which could be helpful in their optimal usage for task-specific applications.

Thermophysical properties of fluids: dynamic viscosity and thermal conductivity

Science.gov (United States)

Latini, G.

2017-11-01

Thermophysical properties of fluids strongly depend upon atomic and molecular structure, complex systems governed by physics laws providing the time evolution. Theoretically the knowledge of the initial position and velocity of each atom, of the interaction forces and of the boundary conditions, leads to the solution; actually this approach contains too many variables and it is generally impossible to obtain an acceptable solution. In many cases it is only possible to calculate or to measure some macroscopic properties of fluids (pressure, temperature, molar volume, heat capacities...). The ideal gas “law,” PV = nRT, was one of the first important correlations of properties and the deviations from this law for real gases were usefully proposed. Moreover the statistical mechanics leads for example to the “hard-sphere” model providing the link between the transport properties and the molecular size and speed of the molecules. Further approximations take into account the intermolecular interactions (the potential functions) which can be used to describe attractions and repulsions. In any case thermodynamics reduces experimental or theoretical efforts by relating one physical property to another: the Clausius-Clapeyron equation provides a classical example of this method and the PVT function must be known accurately. However, in spite of the useful developments in molecular theory and computers technology, often it is usual to search for physical properties when the existing theories are not reliable and experimental data are not available: the required value of the physical or thermophysical property must be estimated or predicted (very often estimation and prediction are improperly used as synonymous). In some cases empirical correlations are useful, if it is clearly defined the range of conditions on which they are based. This work is concerned with dynamic viscosity µ and thermal conductivity λ and is based on clear and important rules to be respected

Turbulent viscosity and scale laws in turbulent jets with variable density; Viscosite turbulente et lois d`echelles dans les jets turbulents a masse volumique variable

Energy Technology Data Exchange (ETDEWEB)

Pietri, L.; Amielh, M.; Anselmet, F.; Fulachier, L. [Institut de Recherche sur les Phinomenes Hors Equilibre Equipe Turbulence, 13 - Marseille (France)

1997-12-31

Turbulent flows with strong density variations, like helium jets in the ambient air, have specific properties linked with the difference of gas densities. This paper presents some experimental results of turbulence properties inside such flows: the Reynolds tensions and the associated turbulent viscosity, and some characteristics linked with the statistical properties of the different turbulence scales. These last results allows to show the complexity of such flows characterized by the influence of external parameters (Reynolds number, initial density ratio, initial momentum flux) that govern the evolution of these parameters inside the jet from the nozzle up to regions where similarity properties are reached. (J.S.) 12 refs.

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.

Behavior of pressure and viscosity at high densities for two-dimensional hard and soft granular materials

NARCIS (Netherlands)

Otsuki, Michio; Hayakawa, Hisao; Luding, Stefan

2010-01-01

The pressure and the viscosity in two-dimensional sheared granular assemblies are investigated numerically. The behavior of both pressure and viscosity is smoothly changing qualitatively when starting from a mono-disperse hard-disk system without dissipation and moving towards a system of (i)

Densities and viscosities of binary mixtures of {dimethylsulfoxide+aliphatic lower alkanols (C1-C3)} at temperatures from T=303.15K to T=323.15K

International Nuclear Information System (INIS)

Bhuiyan, M.M.H.; Ferdaush, J.; Uddin, M.H.

2007-01-01

Densities and viscosities for dimethylsulfoxide (DMSO) with methanol, ethanol, 1-propanol, and 2-propanol have been measured as a function of mole fraction at T=(303.15, 308.15, 313.15, 318.15, and 323.15)K and atmospheric pressure. From the measurements, excess molar volumes (V m E ), excess viscosities (η E ), and Grunberg and Nissan interaction parameters (ε) have been calculated. The excess parameters are fitted to a Redlich-Kister equation. Excess molar volumes (V m E ) are negative for (DMSO+methanol, +ethanol) systems throughout the whole range of composition. The (DMSO+1-propanol) system shows both positive and negative excess molar volumes and (DMSO+2-propanol) shows positive excess molar volume, hardly any negative value is observed in alcohol rich-region. The excess viscosities and interaction parameters of all the mixtures are negative except for the (DMSO+methanol) system which is positive

The viscosity window of the silicate glass foam production

DEFF Research Database (Denmark)

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

2017-01-01

which can offer a practical starting point for the optimisation procedure. The melt viscosity might be the most important parameter for controlling the foaming process and the glass foam density. In this work, we attempt to define a viscosity range in which foaming of different glasses results...... in a maximum of foam expansion. The expansion maximum is obtained for different glasses (labware, E-glass, CRT panel, soda-lime-silica) by foaming with CaCO3 at isokom temperature and from literature data. In general, the viscosity window was found to be within 104–106 Pa s when foaming with MnO2 or metal...... carbonates (CaCO3, Na2CO3, MgCO3, SrCO3, dolomite) whereas SiC requires higher temperatures and correspondingly lower viscosities (103.3–104.0 Pa s). These findings can help assessing the implementation of new resources in the glass foam production....

Effect of water phase transition on dynamic ruptures with thermal pressurization: Numerical simulations with changes in physical properties of water

Science.gov (United States)

Urata, Yumi; Kuge, Keiko; Kase, Yuko

2015-02-01

Phase transitions of pore water have never been considered in dynamic rupture simulations with thermal pressurization (TP), although they may control TP. From numerical simulations of dynamic rupture propagation including TP, in the absence of any water phase transition process, we predict that frictional heating and TP are likely to change liquid pore water into supercritical water for a strike-slip fault under depth-dependent stress. This phase transition causes changes of a few orders of magnitude in viscosity, compressibility, and thermal expansion among physical properties of water, thus affecting the diffusion of pore pressure. Accordingly, we perform numerical simulations of dynamic ruptures with TP, considering physical properties that vary with the pressure and temperature of pore water on a fault. To observe the effects of the phase transition, we assume uniform initial stress and no fault-normal variations in fluid density and viscosity. The results suggest that the varying physical properties decrease the total slip in cases with high stress at depth and small shear zone thickness. When fault-normal variations in fluid density and viscosity are included in the diffusion equation, they activate TP much earlier than the phase transition. As a consequence, the total slip becomes greater than that in the case with constant physical properties, eradicating the phase transition effect. Varying physical properties do not affect the rupture velocity, irrespective of the fault-normal variations. Thus, the phase transition of pore water has little effect on dynamic ruptures. Fault-normal variations in fluid density and viscosity may play a more significant role.

Similarity of dependences of thermal conductivity and density of uranium and tungsten hexafluorides on desublimation conditions

International Nuclear Information System (INIS)

Barkov, V.A.

1989-01-01

Consideration is given to results of investigations of the dependence of thermal conductivity and density of UF 6 and WF 6 desublimates on volume content of hexafluoride in initial gaseous mixture. Similarity of these dependences, as well as the dependences of thermal conductivity of desublimates on their density was revealed. Generalized expressions, relating thermal conductivity and density of desublimates among each ofter and with volume content of hexafluoride in gaseous mixture were derived. Possibility of applying the generalized relations for calculation of thermal conductivity and density of other compounds of MeF 6 type under prescribed desublimation conclitions is shown. 15 refs.; 6 figs

Effects of thermal inflation on small scale density perturbations

Energy Technology Data Exchange (ETDEWEB)

Hong, Sungwook E. [School of Physics, Korea Institute for Advanced Study, 85 Hoegiro, Seoul 130-722 (Korea, Republic of); Lee, Hyung-Joo; Lee, Young Jae; Stewart, Ewan D. [Department of Physics, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-338 (Korea, Republic of); Zoe, Heeseung, E-mail: swhong@kias.re.kr, E-mail: ohsk111@kaist.ac.kr, E-mail: noasac@kaist.ac.kr, E-mail: jcap@profstewart.org, E-mail: heezoe@dgist.ac.kr [School of Basic Science, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 333 Techno jungang-daero, Daegu 711-873 (Korea, Republic of)

2015-06-01

In cosmological scenarios with thermal inflation, extra eras of moduli matter domination, thermal inflation and flaton matter domination exist between primordial inflation and the radiation domination of Big Bang nucleosynthesis. During these eras, cosmological perturbations on small scales can enter and re-exit the horizon, modifying the power spectrum on those scales. The largest modified scale, k{sub b}, touches the horizon size when the expansion changes from deflation to inflation at the transition from moduli domination to thermal inflation. We analytically calculate the evolution of perturbations from moduli domination through thermal inflation and evaluate the curvature perturbation on the constant radiation density hypersurface at the end of thermal inflation to determine the late time curvature perturbation. Our resulting transfer function suppresses the power spectrum by a factor 0∼ 5 at k >> k{sub b}, with k{sub b} corresponding to anywhere from megaparsec to subparsec scales depending on the parameters of thermal inflation. Thus, thermal inflation might be constrained or detected by small scale observations such as CMB distortions or 21cm hydrogen line observations.

The experimental viscosity and calculated relative viscosity of liquid In-Sn allcoys

International Nuclear Information System (INIS)

Wu, A.Q.; Guo, L.J.; Liu, C.S.; Jia, E.G.; Zhu, Z.G.

2007-01-01

The experimental measured viscosity of liquid pure Sn, In 20 Sn 80 and In 80 Sn 20 alloys was studied, and to make a comparison, the calculated relative viscosity based on the pair distribution functions, g(r), has also been studied. There is one peak in each experimental viscosity and calculated relative-viscosity curve of liquid pure Sn about 1000 deg. C. One valley appears in each experimental viscosity and calculated viscosity curve of liquid In 20 Sn 80 alloy about 700 deg. C. There is no abnormal behavior on In 80 Sn 20 alloy. The behavior of experimental viscosity and calculated relative viscosity is coincident with each other. Those results conformed that the temperature-induced structure anomalies reported before did take place

On bulk viscosity and moduli decay

International Nuclear Information System (INIS)

Laine, Mikko

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 Boedeker, 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 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. (author)

Dissimilarities of reduced density matrices and eigenstate thermalization hypothesis

Science.gov (United States)

He, Song; Lin, Feng-Li; Zhang, Jia-ju

2017-12-01

We calculate various quantities that characterize the dissimilarity of reduced density matrices for a short interval of length ℓ in a two-dimensional (2D) large central charge conformal field theory (CFT). These quantities include the Rényi entropy, entanglement entropy, relative entropy, Jensen-Shannon divergence, as well as the Schatten 2-norm and 4-norm. We adopt the method of operator product expansion of twist operators, and calculate the short interval expansion of these quantities up to order of ℓ9 for the contributions from the vacuum conformal family. The formal forms of these dissimilarity measures and the derived Fisher information metric from contributions of general operators are also given. As an application of the results, we use these dissimilarity measures to compare the excited and thermal states, and examine the eigenstate thermalization hypothesis (ETH) by showing how they behave in high temperature limit. This would help to understand how ETH in 2D CFT can be defined more precisely. We discuss the possibility that all the dissimilarity measures considered here vanish when comparing the reduced density matrices of an excited state and a generalized Gibbs ensemble thermal state. We also discuss ETH for a microcanonical ensemble thermal state in a 2D large central charge CFT, and find that it is approximately satisfied for a small subsystem and violated for a large subsystem.

Study of densities, viscosities, and speeds of sound of binary liquid mixtures of butan-1-ol with n-alkanes (C6, C8, and C10) at T = (298.15, 303.15, and 308.15) K

International Nuclear Information System (INIS)

Dubey, Gyan Prakash; Sharma, Monika; Dubey, Neelima

2008-01-01

The densities (ρ) and speeds of sound (u) have been measured over the whole composition range for (butan-1-ol with hexane, or octane, or decane) at T = (298.15, 303.15, and 308.15) K and atmospheric pressure along with the properties of the pure components. Viscosities (η) of these binary mixtures have also been measured over the entire composition range at T 298.15 K. Experimental values of density, viscosity and speed of sound have been used to evaluate excess properties viz. excess molar volumes (V E ), deviation in viscosity (Δη), deviation in speeds of sound (Δu), deviation in isentropic compressibility (Δκ s ) and excess Gibbs free energy of activation of viscous flow (ΔG *E ). The excess properties have been correlated using the Redlich-Kister polynomial equation. The sign and magnitude of these excess properties have been used to interpret the results in terms of intermolecular interactions and structural effects. The viscosity data have also been correlated by Grunberg and Nissan, Tamura-Kurata, and Hind correlation equations

Variable-viscosity thermal hemodynamic slip flow conveying nanoparticles through a permeable-walled composite stenosed artery

Science.gov (United States)

Akbar, Noreen Sher; Tripathi, Dharmendra; Bég, O. Anwar

2017-07-01

This paper presents a mathematical model for simulating viscous, incompressible, steady-state blood flow containing copper nanoparticles and coupled heat transfer through a composite stenosed artery with permeable walls. Wall slip hydrodynamic and also thermal buoyancy effects are included. The artery is simulated as an isotropic elastic tube, following Joshi et al. (2009), and a variable viscosity formulation is employed for the flowing blood. The equations governing the transport phenomena are non-dimensionalized and the resulting boundary value problem is solved analytically in the steady state subject to physically appropriate boundary conditions. Numerical computations are conducted to quantify the effects of relevant hemodynamic, thermophysical and nanoscale parameters emerging in the model on velocity and temperature profiles, wall shear stress, impedance resistance and also streamline distributions. The model may be applicable to drug fate transport modeling with nanoparticle agents and also to the optimized design of nanoscale medical devices for diagnosing stenotic diseases in circulatory systems.

Miscibility gap alloys with inverse microstructures and high thermal conductivity for high energy density thermal storage applications

International Nuclear Information System (INIS)

Sugo, Heber; Kisi, Erich; Cuskelly, Dylan

2013-01-01

New high energy-density thermal storage materials are proposed which use miscibility gap binary alloy systems to operate through the latent heat of fusion of one component dispersed in a thermodynamically stable matrix. Using trial systems Al–Sn and Fe–Cu, we demonstrate the development of the required inverse microstructure (low melting point phase embedded in high melting point matrix) and excellent thermal storage potential. Several other candidate systems are discussed. It is argued that such systems offer enhancement over conventional phase change thermal storage by using high thermal conductivity microstructures (50–400 W/m K); minimum volume of storage systems due to high energy density latent heat of fusion materials (0.2–2.2 MJ/L); and technical utility through adaptability to a great variety of end uses. Low (<300 °C), mid (300–400 °C) and high (600–1400 °C) temperature options exist for applications ranging from space heating and process drying to concentrated solar thermal energy conversion and waste heat recovery. -- Highlights: ► Alloys of immiscible metals are proposed as thermal storage systems. ► High latent heat of fusion per unit volume and tunable temperature are advantageous. ► Thermal storage systems with capacities of 0.2–2.2 MJ/L are identified. ► Heat delivery is via a rigid non-reactive high thermal conductivity matrix. ► The required inverse microstructures were developed for Sn–Al and Cu–Fe systems

Viscosity, granular-temperature, and stress calculations for shearing assemblies of inelastic, frictional disks

International Nuclear Information System (INIS)

Walton, O.R.; Braun, R.L.

1986-01-01

Employing nonequilibrium molecular-dynamics methods the effects of two energy loss mechanisms on viscosity, stress, and granular-temperature in assemblies of nearly rigid, inelastic frictional disks undergoing steady-state shearing are calculated. Energy introduced into the system through forced shearing is dissipated by inelastic normal forces or through frictional sliding during collisions resulting in a natural steady-state kinetic energy density (granular-temperature) that depends on the density and shear rate of the assembly and on the friction and inelasticity properties of the disks. The calculations show that both the mean deviatoric particle velocity and the effective viscosity of a system of particles with fixed friction and restitution coefficients increase almost linearly with strain rate. Particles with a velocity-dependent coefficient of restitution show a less rapid increase in both deviatoric velocity and viscosity as strain rate increases. Particles with highly dissipative interactions result in anisotropic pressure and velocity distributions in the assembly, particularly at low densities. At very high densities the pressure also becomes anisotropic due to high contact forces perpendicular to the shearing direction. The mean rotational velocity of the frictional disks is nearly equal to one-half the shear rate. The calculated ratio of shear stress to normal stress varies significantly with density while the ratio of shear stress to total pressure shows much less variation. The inclusion of surface friction (and thus particle rotation) decreases shear stress at low density but increases shear stress under steady shearing at higher densities

Correlation and extrapolation scheme for the compostition and temperature dependence of viscosity of binary gaseous mixtures: Carbon dioxide + ethane

International Nuclear Information System (INIS)

Hendl, S.; Vogel, E.

1995-01-01

Experimental viscosity data of ethane, carbon dioxide, and three mole fractions of the binary system carbon dioxide + ethane in the temperature range 293.15≤T≤633.15 K and in the density range 0.01≤p≤0.05 mol · L -1 reported earlier were evaluated simultaneously to find out a useful correlation and extrapolation scheme for the viscosity of binary systems in the range of moderate densities. A procedure based on the ideas of the modified Enskog theory has been found to give the best results. Dependent on temperature, the collision diameters related to the equilibrium radial distribution function at contact are fitted to viscosity values of the pure substances and of at least one mixture. The results are compared with experimental data from the literature. A recommendation is given concerning the density range in which the first density contribution to the viscosity coefficient of the system carbon dioxide + ethane is sufficient to be included

3D Suspended Polymeric Microfluidics (SPMF3) with Flow Orthogonal to Bending (FOB) for Fluid Analysis through Kinematic Viscosity

OpenAIRE

Mostapha Marzban; Muthukumaran Packirisamy; Javad Dargahi

2017-01-01

Measuring of fluid properties such as dynamic viscosity and density has tremendous potential for various applications from physical to biological to chemical sensing. However, it is almost impossible to affect only one of these properties, as dynamic viscosity and density are coupled. Hence, this paper proposes kinematic viscosity as a comprehensive parameter which can be used to study the effect of fluid properties applicable to various fluids from Newtonian fluids, such as water, to non-New...

A novel track density measurement method by thermal neutron activation of DYECETs

International Nuclear Information System (INIS)

Sohrabi, M.; Mahdi, Sh.

1995-01-01

A novel track density evaluation method based on thermal neutron activation of some elements of dyed electrochemically etched tracks (DYECETs) of charged particles in detectors like polycarbonate (PC) followed by measurements of gamma activity of the activated detectors is introduced. In this method, the tracks of charged particles like fast neutron-induced recoils in PC detectors were electrochemically etched, dyed by ''QuicDYECET'' methods as recently introduced by us, activated by thermal neutrons and counted for gamma activity determination to be correlated with track density. The activities of elements such as bromine-82 ( 82 Br) and sodium-24 ( 24 Na) on dyes such as Eosin Yellowish, Eosin Bluish, etc. determined by a hyper-pure germanium detector, were found to be in good correlation with DYECET density and thus particle fluence or dose. The effects of different types of dyes and their elements, dye concentration, neutron fluences and ECE durations on the DYECET density responses were studied. This new development is a method of scientific interest, potentially possessing some interesting features, as an alternative method for ECE track density determination using a gamma activity measuring system. It also has the drawback of being applicable only in centres having thermal neutron facilities. The results of the above studies are presented and discussed. (Author)

Uni-axial Elongational Viscosity of Linear and Branched polymer melts

DEFF Research Database (Denmark)

Hassager, Ole; Nielsen, Jens Kromann; Rasmussen, Henrik Koblitz

2005-01-01

About 40 years ago interest in the measurement of elongational viscosity of polymer melts started to grow. Here we present measurements of transient (and steady) uni-axial elongational viscosity, using the FSR, of the following melts: Four narrow MMD polystyrene (PS) samples with weight......-average molar mass Mw in the range of 50k to 390k. Three different bi-disperse samples, mixed from the narrow MMD PS. Two low-density polyethylene (LDPE) melts (Lupolen 1840D and 3020D). A steady-state viscosity was kept for 1-2.5 Hencky strain units in all measurements.The measurements on the bi-disperse PS...... melts have demonstrated that both the transient and steady elongational viscosity is quite sensitive to polydispersity. Bi-disperse PS resembles the behaviour of mono-disperse melts only at elongational rates larger then the inverse of maximal time constant of the smallest molecule. As observed in Boger...

Determination of Viscosity-Average Molecular Weight of Chitosan using Intrinsic Viscosity Measurement

International Nuclear Information System (INIS)

Norzita Yacob; Norhashidah Talip; Maznah Mahmud

2011-01-01

Molecular weight of chitosan can be determined by different techniques such as Gel Permeation Chromatography (GPC), Static Light Scattering (SLS) and intrinsic viscosity measurement. Determination of molecular weight by intrinsic viscosity measurement is a simple method for characterization of chitosan. Different concentrations of chitosan were prepared and measurement was done at room temperature. The flow time data was used to calculate the intrinsic viscosity by extrapolating the reduced viscosity to zero concentration. The value of intrinsic viscosity was then recalculated into the viscosity-average molecular weight using Mark-Houwink equation. (author)

Density Changes in the Optimized CSSX Solvent System

Energy Technology Data Exchange (ETDEWEB)

Lee, D.D.

2002-11-25

Density increases in caustic-side solvent extraction (CSSX) solvent have been observed in separate experimental programs performed by different groups of researchers. Such changes indicate a change in chemical composition. Increased density adversely affects separation of solvent from denser aqueous solutions present in the CSSX process. Identification and control of factors affecting solvent density are essential for design and operation of the centrifugal contactors. The goals of this research were to identify the factors affecting solvent density (composition) and to develop correlations between easily measured solvent properties (density and viscosity) and the chemical composition of the solvent, which will permit real-time determination and adjustment of the solvent composition. In evaporation experiments, virgin solvent was subjected to evaporation under quiescent conditions at 25, 35, and 45 C with continuously flowing dry air passing over the surface of the solvent. Density and viscosity were measured periodically, and chemical analysis was performed on the solvent samples. Chemical interaction tests were completed to determine if any chemical reaction takes place over extended contact time that changes the composition and/or physical properties. Solvent and simulant, solvent and strip solution, and solvent and wash solution were contacted continuously in agitated flasks. They were periodically sampled and the density measured (viscosity was also measured on some samples) and then submitted to the Chemical Sciences Division of Oak Ridge National Laboratory for analysis by nuclear magnetic resonance (NMR) spectrometry and high-performance liquid chromatography (HPLC) using the virgin solvent as the baseline. Chemical interaction tests showed that solvent densities and viscosities did not change appreciably during contact with simulant, strip, or wash solution. No effects on density and viscosity and no chemical changes in the solvent were noted within

Densities, viscosities, and excess properties of binary mixtures of two imidazolide anion functionalized ionic liquids with water at T = (293.15 to 313.15) K

International Nuclear Information System (INIS)

Chen, Lingxiao; Chen, Jiayi; Song, Zihao; Cui, Guokai; Xu, Yingjie; Wang, Xuhong; Liu, Jian

2015-01-01

Highlights: • Densities and viscosities of binary mixtures of [HDBU]IM and [BDBU]IM with water were measured. • Excess molar volumes and viscosity deviations were calculated and fitted to Redlich–Kister equation. • Other volumetric properties and excess Gibbs free energy of activation for viscous flow were deduced. • The intermolecular interactions between water and [HDBU]IM or [BDBU]IM were analyzed and compared. - Abstract: Densities and viscosities of binary mixtures of 8-hydrogen-1,8-diazabicyclo[5,4,0]-undec-7-enium imidazolide ([HDBU]IM) and 8-butyl-1,8-diazabicyclo[5,4,0]-undec-7-enium imidazolide ([BDBU]IM) ionic liquids (ILs) with water were measured at temperatures from T = (293.15 to 313.15) K. Excess molar volumes V"E and viscosity deviations Δη of the mixtures were calculated to study the intermolecular interactions and structural factors between ILs and water. The results show that the V"E values of the two mixtures are negative over the whole composition range, while the Δη values have positive deviations, indicating that the hydrogen bonding interactions between IL and water are dominant in the mixtures. Moreover, the absolute values of V"E (|V"E|) of {[HDBU]IM (1) + H_2O (2)} system are larger than those of {[BDBU]IM (1) + H_2O (2)} system at the same condition, indicating that the hydrogen bonding interactions between [HDBU]IM and water are stronger than those between [BDBU]IM and water. Both |V"E| and Δη values of the mixtures decrease with the increasing temperature, resulting from the decreasing the hydrogen bonding interactions between IL and water. Other derived properties of the studied systems, such as the apparent molar volumes, partial molar volumes, excess partial molar volumes, Gibbs free energy of activation for viscous flow, and excess Gibbs free energy of activation for viscous flow were also calculated from the experimental values.

Viscosity Measurement: A Virtual Experiment - Abstract of Issues 9907W

Science.gov (United States)

Papadopoulos, N.; Pitta, A. T.; Markopoulos, N.; Limniou, M.; Lemos, M. A. N. D. A.; Lemos, F.; Freire, F. G.

1999-11-01

Viscosity Measurement: A Virtual Experiment simulates a series of viscosity experiments. Viscosity is an important subject in chemistry and chemical engineering. It is important when dealing with intermolecular forces in liquids and gases and it has enormous relevance in all technological aspects of equipment dealing with liquids or gases. Most university-level chemistry courses include viscosity to some extent. Viscosity Measurement includes three virtual experiments: an Ostwald viscometer simulator, a falling-ball viscometer simulator, and a balance simulator for a simple determination of the density of a liquid. The Ostwald viscometer simulator and the balance simulator allow the student to find out how composition and temperature influence the density and viscosity of an ethanol-water mixture. The falling-ball viscometer simulator allows the student to determine experimentally the size and density of the ball required to measure viscosity of various liquids. Each virtual experiment includes a corresponding theoretical section. Support from the program is sufficient to enable the students to carry out a virtual experiment sensibly and on their own. Preparation is not essential. Students can use the program unsupervised, thus saving staff time and allowing flexibility in students' time. The design of the program interface plays a key role in the success of a simulated experiment. Direct manipulation has greater intuitive appeal than alternative interface forms such as menus and has been observed to provide performance and learning advantages (1). We tried to design an interface that is visually attractive, is user friendly with simple and intuitive navigation, and provides appropriate schematic animations to clarify the principles of the laboratory procedures. The opening screen presents the virtual experiments that can be selected. Clicking an icon takes the student to the appropriate section. Viscosity Measurement allows the student to concentrate on the

Modified free volume theory of self-diffusion and molecular theory of shear viscosity of liquid carbon dioxide.

Science.gov (United States)

Nasrabad, Afshin Eskandari; Laghaei, Rozita; Eu, Byung Chan

2005-04-28

In previous work on the density fluctuation theory of transport coefficients of liquids, it was necessary to use empirical self-diffusion coefficients to calculate the transport coefficients (e.g., shear viscosity of carbon dioxide). In this work, the necessity of empirical input of the self-diffusion coefficients in the calculation of shear viscosity is removed, and the theory is thus made a self-contained molecular theory of transport coefficients of liquids, albeit it contains an empirical parameter in the subcritical regime. The required self-diffusion coefficients of liquid carbon dioxide are calculated by using the modified free volume theory for which the generic van der Waals equation of state and Monte Carlo simulations are combined to accurately compute the mean free volume by means of statistical mechanics. They have been computed as a function of density along four different isotherms and isobars. A Lennard-Jones site-site interaction potential was used to model the molecular carbon dioxide interaction. The density and temperature dependence of the theoretical self-diffusion coefficients are shown to be in excellent agreement with experimental data when the minimum critical free volume is identified with the molecular volume. The self-diffusion coefficients thus computed are then used to compute the density and temperature dependence of the shear viscosity of liquid carbon dioxide by employing the density fluctuation theory formula for shear viscosity as reported in an earlier paper (J. Chem. Phys. 2000, 112, 7118). The theoretical shear viscosity is shown to be robust and yields excellent density and temperature dependence for carbon dioxide. The pair correlation function appearing in the theory has been computed by Monte Carlo simulations.

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

Directory of Open Access Journals (Sweden)

Fernanda Papa Spada

2012-03-01

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

Influence of thermal buoyancy on vertical tube bundle thermal density head predictions under transient conditions

International Nuclear Information System (INIS)

Lin, H.C.; Kasza, K.E.

1984-01-01

The thermal-hydraulic behavior of an LMFBR system under various types of plant transients is usually studied using one-dimensional (1-D) flow and energy transport models of the system components. Many of the transient events involve the change from a high to a low flow with an accompanying change in temperature of the fluid passing through the components which can be conductive to significant thermal bouyancy forces. Thermal bouyancy can exert its influence on system dynamic energy transport predictions through alterations of flow and thermal distributions which in turn can influence decay heat removal, system-response time constants, heat transport between primary and secondary systems, and thermal energy rejection at the reactor heat sink, i.e., the steam generator. In this paper the results from a comparison of a 1-D model prediction and experimental data for vertical tube bundle overall thermal density head and outlet temperature under transient conditions causing varying degrees of thermal bouyancy are presented. These comparisons are being used to generate insight into how, when, and to what degree thermal buoyancy can cause departures from 1-D model predictions

Investigation of Thermal Properties of High-Density Polyethylene/Aluminum Nanocomposites by Photothermal Infrared Radiometry

Science.gov (United States)

Koca, H. D.; Evgin, T.; Horny, N.; Chirtoc, M.; Turgut, A.; Tavman, I. H.

2017-12-01

In this study, thermal properties of high-density polyethylene (HDPE) filled with nanosized Al particles (80 nm) were investigated. Samples were prepared using melt mixing method up to filler volume fraction of 29 %, followed by compression molding. By using modulated photothermal radiometry (PTR) technique, thermal diffusivity and thermal effusivity were obtained. The effective thermal conductivity of nanocomposites was calculated directly from PTR measurements and from the measurements of density, specific heat capacity (by differential scanning calorimetry) and thermal diffusivity (obtained from PTR signal amplitude and phase). It is concluded that the thermal conductivity of HDPE composites increases with increasing Al fraction and the highest effective thermal conductivity enhancement of 205 % is achieved at a filler volume fraction of 29 %. The obtained results were compared with the theoretical models and experimental data given in the literature. The results demonstrate that Agari and Uno, and Cheng and Vachon models can predict well the thermal conductivity of HDPE/Al nanocomposites in the whole range of Al fractions.

Thermal degradation of a synthetic lube oil API SL/CF SAE 5W 40; Degradacao termica do oleo lubrificante sintetico API SL/CF SAE 5W 40

Energy Technology Data Exchange (ETDEWEB)

Lopes, Eddy H. de O.; Carvalho, Laura H. de; Silva, Everson de L. [Universidade Federal de Campina Grande (UFCG), PB (Brazil)

2008-07-01

This work deals with the thermal degradation to 210 deg C of lubricating oil synthetic API SL/CF SAE 5W 40 as received and on the presence of metallic particles, from engine parts (head and crankshaft). Samples were collected at various intervals of time. The metallic particles were spent in mesh sieve no. 200 (0.074 mm) and used both in the trials of characterization (EDX and SEM) as the thermal degradation of the oil. Changes in rheology, viscosity, density, color and FTIR were monitored over time of heat exposure. The results indicate that thermal exposure caused by thermal oxidation of synthetic oil and that the presence of metallic particles (10 ppm) accelerated this process, so it is suggested that during the exchange of oil are taken care to remove them from to prevent the premature deterioration of the new oil. The behaviour Newtonian was maintained throughout the period degradation and viscosity of the oil has not changed significantly even after long periods (1148 hours) of thermal exposure. Despite the density of oil also has not changed significantly with time of exposure, changes in color indicate that chemical changes occurred, which was detected by FTIR. (author)

Shear viscosity from Kubo formalism: NJL model study

International Nuclear Information System (INIS)

Lang, Robert; Weise, Wolfram

2014-01-01

A large-N c expansion is combined with the Kubo formalism to study the shear viscosity η of strongly interacting matter in the two-flavor NJL model. We discuss analytical and numerical approaches to η and investigate systematically its strong dependence on the spectral width and the momentum-space cutoff. Thermal effects on the constituent quark mass from spontaneous chiral symmetry breaking are included. The ratio η/s and its thermal dependence are derived for different parameterizations of the spectral width and for an explicit one-loop calculation including mesonic modes within the NJL model. (orig.)

Influence of polypropylene fibres on the tensile strength and thermal properties of various densities of foamed concrete

Science.gov (United States)

Jhatial, Ashfaque Ahmed; Inn, Goh Wan; Mohamad, Noridah; Johnson Alengaram, U.; Mo, Kim Hung; Abdullah, Redzuan

2017-11-01

As almost half of the world’s population now lives in the urban areas, the raise in temperature in these areas has necessitated the development of thermal insulating material. Conventional concrete absorbs solar radiation during the daytime while releasing it at night causing raise in temperature in urban areas. The thermal conductivity of 2200 kg/m3 density conventional concrete is 1.6 W/mK. Higher the thermal conductivity value, greater the heat flow through the material. To reduce this heat transfer, the construction industry has turned to lightweight foamed concrete. Foamed concrete, due to its air voids, gives excellent thermal properties and sound absorption apart from fire-resistance and self-leveling properties. But due to limited studies on different densities of foamed concrete, the thermal properties are not understood properly thus limiting its use as thermal insulating material. In this study, thermal conductivity is determined for 1400, 1600 and 1800 kg/m3 densities of foamed concrete. 0.8% of Polypropylene fibres (PP) is used to reinforce the foamed concrete and improve the mechanical properties. Based upon the results, it was found that addition of PP fibres enhances the tensile strength and slightly reduced the thermal conductivity for lower densities, while the reverse affect was noticed in 1800 kg/m3 density.

Computing thermal Wigner densities with the phase integration method

International Nuclear Information System (INIS)

Beutier, J.; Borgis, D.; Vuilleumier, R.; Bonella, S.

2014-01-01

We discuss how the Phase Integration Method (PIM), recently developed to compute symmetrized time correlation functions [M. Monteferrante, S. Bonella, and G. Ciccotti, Mol. Phys. 109, 3015 (2011)], can be adapted to sampling/generating the thermal Wigner density, a key ingredient, for example, in many approximate schemes for simulating quantum time dependent properties. PIM combines a path integral representation of the density with a cumulant expansion to represent the Wigner function in a form calculable via existing Monte Carlo algorithms for sampling noisy probability densities. The method is able to capture highly non-classical effects such as correlation among the momenta and coordinates parts of the density, or correlations among the momenta themselves. By using alternatives to cumulants, it can also indicate the presence of negative parts of the Wigner density. Both properties are demonstrated by comparing PIM results to those of reference quantum calculations on a set of model problems

Computing thermal Wigner densities with the phase integration method.

Science.gov (United States)

Beutier, J; Borgis, D; Vuilleumier, R; Bonella, S

2014-08-28

We discuss how the Phase Integration Method (PIM), recently developed to compute symmetrized time correlation functions [M. Monteferrante, S. Bonella, and G. Ciccotti, Mol. Phys. 109, 3015 (2011)], can be adapted to sampling/generating the thermal Wigner density, a key ingredient, for example, in many approximate schemes for simulating quantum time dependent properties. PIM combines a path integral representation of the density with a cumulant expansion to represent the Wigner function in a form calculable via existing Monte Carlo algorithms for sampling noisy probability densities. The method is able to capture highly non-classical effects such as correlation among the momenta and coordinates parts of the density, or correlations among the momenta themselves. By using alternatives to cumulants, it can also indicate the presence of negative parts of the Wigner density. Both properties are demonstrated by comparing PIM results to those of reference quantum calculations on a set of model problems.

Computational Design of Non-natural Sugar Alcohols to Increase Thermal Storage Density: Beyond Existing Organic Phase Change Materials.

Science.gov (United States)

Inagaki, Taichi; Ishida, Toyokazu

2016-09-14

Thermal storage, a technology that enables us to control thermal energy, makes it possible to reuse a huge amount of waste heat, and materials with the ability to treat larger thermal energy are in high demand for energy-saving societies. Sugar alcohols are now one promising candidate for phase change materials (PCMs) because of their large thermal storage density. In this study, we computationally design experimentally unknown non-natural sugar alcohols and predict their thermal storage density as a basic step toward the development of new high performance PCMs. The non-natural sugar alcohol molecules are constructed in silico in accordance with the previously suggested molecular design guidelines: linear elongation of a carbon backbone, separated distribution of OH groups, and even numbers of carbon atoms. Their crystal structures are then predicted using the random search method and first-principles calculations. Our molecular simulation results clearly demonstrate that the non-natural sugar alcohols have potential ability to have thermal storage density up to ∼450-500 kJ/kg, which is significantly larger than the maximum thermal storage density of the present known organic PCMs (∼350 kJ/kg). This computational study suggests that, even in the case of H-bonded molecular crystals where the electrostatic energy contributes mainly to thermal storage density, the molecular distortion and van der Waals energies are also important factors to increase thermal storage density. In addition, the comparison between the three eight-carbon non-natural sugar alcohol isomers indicates that the selection of preferable isomers is also essential for large thermal storage density.

The Role of Viscosity in Causing the Plasma Poloidal Motion in Magnetic Clouds

Energy Technology Data Exchange (ETDEWEB)

Zhao, Ake; Wang, Yuming; Liu, Jiajia; Zhou, Zhenjun; Shen, Chenglong; Liu, Rui; Zhuang, Bin; Zhang, Quanhao, E-mail: ymwang@ustc.edu.cn [CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, Anhui 230026 (China)

2017-08-20

An interesting phenomenon, plasma poloidal motion, has been found in many magnetic clouds (MCs), and viscosity has been proposed as a possible mechanism. However, it is not clear how significant the role of viscosity is in generating such motion. In this paper, we conduct a statistical study of the MCs detected by the Wind spacecraft during 1995–2012. It is found that, for 19% of all the studied MCs (186), the poloidal velocities of the MC plasma near the MC boundaries are well correlated with those of the corresponding ambient solar wind plasma. A non-monotonic increase from inner to outer MCs suggests that the viscosity does play a role, albeit weak, on the poloidal motion in the MC statistically. The possible dependence on the solar wind parameters is then studied in detail for the nine selected crossings, which represent the viscosity characteristic. There is an evident negative correlation between the viscosity and the density, a weak negative correlation between the viscosity and the turbulence strength, and no clear correlation between the viscosity and the temperature.

Effects of SOC-dependent electrolyte viscosity on performance of vanadium redox flow batteries

International Nuclear Information System (INIS)

Xu, Q.; Zhao, T.S.; Zhang, C.

2014-01-01

Highlights: • The correlations of electrolyte viscosity and SOC are obtained. • Effect of SOC-dependent electrolyte viscosity is considered in this model. • This model enables a more realistic simulation of variable distributions. • It provides accurate estimations of pumping work and system efficiency. - Abstract: The viscosity of the electrolyte in vanadium redox flow batteries (VRFBs) varies during charge and discharge as the concentrations of acid and vanadium ions in the electrolyte continuously change with the state of charge (SOC). In previous VRFB models, however, the electrolyte has been treated as a constant-viscosity solution. In this work, a mass-transport and electrochemical model taking account of the effect of SOC-dependent electrolyte viscosity is developed. The comparison between the present model and the model with the constant-viscosity simplification indicates that the consideration of the SOC-dependent electrolyte viscosity enables (i) a more realistic simulation of the distributions of overpotential and current density in the electrodes, and (ii) more accurate estimations of pumping work and the system efficiency of VRFBs

Determination of the viscosity by spherical drop using nuclear tecniques

International Nuclear Information System (INIS)

Silva, F.V. da; Qassim, R.Y.; Souza, Roberto de; Rio de Janeiro Univ.

1983-01-01

The measurements of the drop limit velocity of a Sphere in a fluid using a radiotracer method are analyzed. The dynamic process involved was observed, identifying the density and viscosity of the fluid. (E.G.) [pt

Modeling density-driven flow in porous media principles, numerics, software

CERN Document Server

Holzbecher, Ekkehard O

1998-01-01

Modeling of flow and transport in groundwater has become an important focus of scientific research in recent years. Most contributions to this subject deal with flow situations, where density and viscosity changes in the fluid are neglected. This restriction may not always be justified. The models presented in the book demonstrate immpressingly that the flow pattern may be completely different when density changes are taken into account. The main applications of the models are: thermal and saline convection, geothermal flow, saltwater intrusion, flow through salt formations etc. This book not only presents basic theory, but the reader can also test his knowledge by applying the included software and can set up own models.

Effect of gamma irradiation on density and thermal expansion changes of uniaxial oriented LLDPE

International Nuclear Information System (INIS)

Kacarevic-Popovic, Z.; Kostoski, D.; Novakovic, Lj.

1998-01-01

Complete text of publication follows. It is well known that gamma irradiation induces cross-linking in the amorphous phase of isotropic polyethylene, or chain scission in highly oriented fibers and films. Thermomechanical behavior and values of density are the reflection of the changes induced by gamma irradiation. Namely, scission of macromolecules, in general, increases thermal expansion coefficient and decreases density and vice versa. On the other hand, as it is well known, the thermal expansion behavior of oriented polymers shows marked anisotropy. It was found that many highly oriented polymers show a negative coefficient of thermal expansion in the draw direction and a positive coefficient in the transverse direction. It has been suggested that, apart from any intrinsic crystalline contribution, a significant part of the negative thermal expansion coefficients obtained for highly oriented polymers arises from the effect of entropy internal stresses in the amorphous regions. From our previous work, the thermal coefficients in draw direction of irradiated samples rise in the glass transition temperature range and it was related to the effects of cross-linking in the amorphous phase of LDPE. In our present work we observed initial decrease in density with absorbed dose, up to 35 kGy, and subsequent increase up to a dose of 500 kGy. The observed increase in thermal expansion coefficient followed the changes in density and is related to the parallel processes of chain scission and net cross-linking in the amorphous phase of LLDPE, induced by gamma irradiation

Minijet thermalization and diffusion of transverse momentum correlation in high-energy heavy-ion collisions

International Nuclear Information System (INIS)

Pang Longgang; Wang Qun; Wang Xinnian; Xu Rong

2010-01-01

Transverse momentum correlations in the azimuthal angle of hadrons produced owing to minijets are first studied within the HIJING Monte Carlo model in high-energy heavy-ion collisions. Quenching of minijets during thermalization is shown to lead to significant diffusion (broadening) of the correlation. Evolution of the transverse momentum density fluctuation that gives rise to this correlation in azimuthal angle in the later stage of heavy-ion collisions is further investigated within a linearized diffusion-like equation and is shown to be determined by the shear viscosity of the evolving dense matter. This diffusion equation for the transverse momentum fluctuation is solved with initial values given by HIJING and together with the hydrodynamic equation for the bulk medium. The final transverse momentum correlation in azimuthal angle is calculated along the freeze-out hypersurface and is found to be further diffused for higher values of the shear viscosity to entropy density ratio, η/s∼0.2-0.4. Therefore the final transverse momentum correlation in azimuthal angle can be used to study the thermalization of minijets in the early stage of heavy-ion collisions and the viscous effect in the hydrodynamic evolution of strongly coupled quark-gluon plasma.

High-Viscosity Oil Filtration in the Pool Under Thermal Action

Science.gov (United States)

Shagapov, V. Sh.; Yumagulova, Yu. A.; Gizzatullina, A. A.

2018-05-01

We have developed a mathematical model and constructed numerical solutions of the problem of heating a high-viscosity oil pool through one horizontal well or a system of wells and have shown the possibility of their further operation until the limiting profitable discharge of oil is attained. The expenditure of heat in heating the oil pool, the evolution of discharge of oil, and the mass of extracted oil over the considered period have been considered.

Determination of viscosity-average molecular weight of chitosan using intrinsic viscosity measurement

International Nuclear Information System (INIS)

Norzita Yacob; Norhashidah Talip; Maznah Mahmud; Nurul Aizam Idayu Mat Sani; Nor Akma Samsuddin; Norafifah Ahmad Fabillah

2013-01-01

Determination of molecular weight by intrinsic viscosity measurement is a simple method for characterization of chitosan. To study the effect of radiation on molecular weight, chitosan was first irradiated using electron beam at different doses prior to measurement. Different concentrations of chitosan were prepared and measurement was done at room temperature. The flow time data was used to calculate the intrinsic viscosity by extrapolating the reduced viscosity to zero concentration. The value of intrinsic viscosity was then recalculated into the viscosity-average molecular weight using Mark-Houwink equation. (Author)

Near-surface viscosity measurements with a love acoustic wave device

International Nuclear Information System (INIS)

Collings, A.F.; Cooper, B.J.; Lappas, S.; Sor, J.A.

1999-01-01

Full text: In the last decade, considerable research effort has been directed towards interfacing piezoelectric transducers with biological detection systems to produce efficient and highly selective biosensors. Several types of piezoelectric or, more specifically, acoustic wave transducers have been investigated. Our group has developed Love wave (guided surface skimming wave) devices which are made by attaching a thin overlayer with the appropriate acoustic properties to the surface of a conventional surface horizontal mode device. An optimised layer concentrates most of the propagating wave energy in the guiding layer and can improve the device sensitivity in detecting gas-phase mass loading on the surface some 20- to 40-fold. Love wave devices used in liquid phase sensing will also respond to viscous, as well as mass, loading on the device surface. We have studied the propagation of viscous waves into liquid sitting on a Love wave device both theoretically and experimentally. Modelling of the effect of a viscous liquid layer on a Love wave propagating in a layered medium predicts the velocity profile in the solid substrate and in the adjoining liquid. This is a function of the thickness of the guiding layer, the elastic properties of the guiding layer and the piezoelectric substrate, and of the viscosity and density of the liquid layer. We report here on measurements of the viscosity of aqueous glycerine solutions made with a quartz Love wave device with a 5.5 μm SiO 2 guiding layer. The linear relationship between the decrease in the device frequency and the square root of the viscosity density product is accurately observed at Newtonian viscosities. At higher viscosities, there is an increase in damping, the insertion loss of the device saturates, Δf is no longer proportional to (ηp) l/2 and reaches a maximum. We also show results for the determination of the gelation time in protein and inorganic aqueous gels and for the rate of change of viscosity with

T-junction cross-flow mixing with thermally driven density stratification

Energy Technology Data Exchange (ETDEWEB)

Kickhofel, John, E-mail: jkickhofel@gmail.com [Laboratory of Nuclear Energy Systems, ETH Zurich, Sonneggstrasse 3, 8057 Zurich (Switzerland); Prasser, Horst-Michael, E-mail: prasser@lke.mavt.ethz.ch [Laboratory of Nuclear Energy Systems, ETH Zurich, Sonneggstrasse 3, 8057 Zurich (Switzerland); Selvam, P. Karthick, E-mail: karthick.selvam@ike.uni-stuttgart.de [Institute of Nuclear Technology and Energy Systems (IKE), University of Stuttgart, Pfaffenwaldring 31, 70569 Stuttgart (Germany); Laurien, Eckart, E-mail: eckart.laurien@ike.uni-stuttgart.de [Institute of Nuclear Technology and Energy Systems (IKE), University of Stuttgart, Pfaffenwaldring 31, 70569 Stuttgart (Germany); Kulenovic, Rudi, E-mail: rudi.kulenovic@ike.uni-stuttgart.de [Institute of Nuclear Technology and Energy Systems (IKE), University of Stuttgart, Pfaffenwaldring 31, 70569 Stuttgart (Germany)

2016-12-01

Highlights: • Mesh sensor for realistic nuclear thermal hydraulic scenarios is demonstrated. • Flow temperature behavior across a wide range of Richardson numbers measured. • Upstream stratified flow in the T-junction results in a thermal shock scenario. • Large, stable near-wall thermal gradients exist in spite of turbulent flows. - Abstract: As a means of further elucidating turbulence- and stratification-driven thermal fatigue in the vicinity of T-junctions in nuclear power plants, a series of experiments have been conducted at the high temperature high pressure fluid–structure interaction T-junction facility of the University of Stuttgart with novel fluid measurement instrumentation. T-junction mixing with large fluid temperature gradients results in complex flow behavior, the result of density driven effects. Deionized water mixing at temperature differences of up to 232 K at 7 MPa pressure have been investigated in a T-junction with main pipe diameter 71.8 mm and branch line diameter 38.9 mm. The experiments have been performed with fixed flow rates of 0.4 kg/s in the main pipe and 0.1 kg/s in the branch line. A novel electrode-mesh sensor compatible with the DN80 PN100 pipeline upstream and downstream of the T-junction has been utilized as a temperature sensor providing a high density information in the pipe cross-section in both space and time. Additionally, in-flow and in-wall thermocouples quantify the damping of thermal fluctuations by the wall material. The results indicate that large inflow temperature differences lead to strong turbulence damping, and ultimately stable stratification extending both downstream and upstream of the T-junction resulting in large local thermal gradients.

Concentration dependences of the density, viscosity, and refraction index of Cu(NO3)2 · 3H2O solutions in DMSO at 298 K

Science.gov (United States)

Mamyrbekova, A. K.

2013-03-01

Physicochemical properties (density, dynamic viscosity, refraction index) of the DMSO-Cu(NO3)2 · 3H2O system are studied in the concentration range of 0.01-2 M at 298 K. The refraction index of a solution of copper(II) nitrate in dimethylsulfoxide (DMSO) is measured at 288-318 K. The excess and partial molar volumes of the solvent and dissolved substance are calculated analytically.

Applicability of Stokes method for measuring viscosity of mixtures with concentration gradient

Directory of Open Access Journals (Sweden)

César Medina

2017-12-01

Full Text Available After measuring density and viscosity of a mixture of glycerin and water contained in a vertical pipe, a variation of these properties according to depth is observed. These gradients are typical of non-equilibrium states related to the lower density of water and the fact that relatively long times are necessary to achieve homogeneity. In the same pipe, the falling velocity of five little spheres is measured as a function of depth, and then a numerical fit is performed which agrees very well with experimental data. Based on the generalization of these results, the applicability of Stokes method is discussed for measuring viscosity of mixtures with a concentration gradient.

Temperature dependent kinematic viscosity of different types of engine oils

Directory of Open Access Journals (Sweden)

Libor Severa

2009-01-01

Full Text Available The objective of this study is to measure how the viscosity of engine oil changes with temperature. Six different commercially distributed engine oils (primarily intended for motorcycle engines of 10W–40 viscosity grade have been evaluated. Four of the oils were of synthetic type, two of semi–synthetic type. All oils have been assumed to be Newtonian fluids, thus flow curves have not been determined. Oils have been cooled to below zero temperatures and under controlled temperature regulation, kinematic viscosity (mm2 / s have been measured in the range of −5 °C and +115 °C. Anton Paar digital viscometer with concentric cylinders geometry has been used. In accordance with expected behavior, kinematic viscosity of all oils was decreasing with increasing temperature. Viscosity was found to be independent on oil’s density. Temperature dependence has been modeled using se­ve­ral mathematical models – Vogel equation, Arrhenius equation, polynomial, and Gaussian equation. The best match between experimental and computed data has been achieved for Gaussian equation (R2 = 0.9993. Knowledge of viscosity behavior of an engine oil as a function of its temperature is of great importance, especially when considering running efficiency and performance of combustion engines. Proposed models can be used for description and prediction of rheological behavior of engine oils.

Thermal Analysis of Low Layer Density Multilayer Insulation Test Results

Science.gov (United States)

Johnson, Wesley L.

2011-01-01

Investigation of the thermal performance of low layer density multilayer insulations is important for designing long-duration space exploration missions involving the storage of cryogenic propellants. Theoretical calculations show an analytical optimal layer density, as widely reported in the literature. However, the appropriate test data by which to evaluate these calculations have been only recently obtained. As part of a recent research project, NASA procured several multilayer insulation test coupons for calorimeter testing. These coupons were configured to allow for the layer density to be varied from 0.5 to 2.6 layer/mm. The coupon testing was completed using the cylindrical Cryostat-l00 apparatus by the Cryogenics Test Laboratory at Kennedy Space Center. The results show the properties of the insulation as a function of layer density for multiple points. Overlaying these new results with data from the literature reveals a minimum layer density; however, the value is higher than predicted. Additionally, the data show that the transition region between high vacuum and no vacuum is dependent on the spacing of the reflective layers. Historically this spacing has not been taken into account as thermal performance was calculated as a function of pressure and temperature only; however the recent testing shows that the data is dependent on the Knudsen number which takes into account pressure, temperature, and layer spacing. These results aid in the understanding of the performance parameters of MLI and help to complete the body of literature on the topic.

Thermal Cracking of Low Density Polyethylene (LDPE) Waste into ...

African Journals Online (AJOL)

Waste low density polyethylene film (table water sachets) was converted into solid, liquid oil and gaseous products by thermal process in a self- designed stainless steel laboratory reactor. The waste polymer was completely pyrolized within the temperature range of 474 – 520°C and 2hours reaction time. The solid residue ...

Use of Kinematic Viscosity Data for the Evaluation of the Molecular Weight of Petroleum Oils

Science.gov (United States)

Maroto, J. A.; Quesada-Perez, M.; Ortiz-Hernandez, A. J.

2010-01-01

A new laboratory procedure for the evaluation of the mean molecular weight (mean relative molecular mass) of petroleum oils with high accuracy is described. The density and dynamic viscosity of three commercial petroleum oils are measured at different temperatures. These experimental data are used to calculate the kinematic viscosity as a function…

Densities, speeds of sound and viscosities of binary mixtures of tetrahydrofuran with 1-hexanol, 1-octanol and 1-decanol at T = (298.15 to 313.15) K

International Nuclear Information System (INIS)

Dubey, Gyan Prakash; Kumar, Rajiv

2014-01-01

Highlights: • Thermodynamic study for the binary liquid mixtures has been made. has been made. • Excess molar volumes, deviations of speed of sound and excess molar isentropic compressibilities were determined. • Discussion has been carried out on the basis of types of interactions between the liquid molecules based on derived properties. -- Abstract: Density ρ, and speed of sound u, have been measured for the binary mixtures of tetrahydrofuran (C 4 H 8 O) with 1-hexanol, (C 6 H 14 O), 1-octanol, (C 8 H 18 O) and 1-decanol, (C 10 H 22 O) over the entire composition range at T = (298.15, 303.15, 308.15 and 313.15) K and at atmospheric pressure while viscosity, η was measured at T = (298.15, 303.15, 308.15) K and at atmospheric pressure. The experimental density and speed of sound values were used to calculate the excess molar volumes VmE, deviations in speed of sound u D and excess molar isentropic compressibility K S,m E , while the viscosity data were used to compute excess Gibbs energy of activation of viscous flow, ΔG *E at 298.15, 303.15 and 308.15 K. The values of VmE, u D and K S,m E were fitted to the Redlich–Kister polynomial equation and the viscosity data have been correlated by using the equations of Grunberg–Nissan, Tamura–Kurata, Hind et al., Heric–Brewer (three parameter) and McAllister (four body interactions) and have been used to discuss the presence of significant interactions between cyclic ether and alcohols

On the measurement of the relative viscosity of suspensions

International Nuclear Information System (INIS)

Acrivos, A.; Fan, X.; Mauri, R.

1994-01-01

The relative viscosity of a suspension of rigid, noncolloidal particles immersed in a Newtonian fluid was measured in a Couette device and was found to be shear thinning even for values of the solids fraction as low as 20%. Although such behavior was reported previously, no satisfactory explanation appears to have been given thus far. It shall be shown presently, however, that, at least for our systems, this shear-thinning effect was due to a slight mismatch in the densities of the two phases. Moreover, the apparent relative viscosities measured in our apparatus were found to be in excellent agreement with those predicted theoretically using a model, originally proposed by Leighton and Acrivos [Chem. Eng. Sci. 41, 1377--1384 (1986)], to describe viscous resuspension, according to which the measured relative viscosity should depend on the bulk particle concentration and on the dimensionless Shields number A, and should attain its correct value for a well-mixed suspension only as A→∞. The predictions of this model are also in excellent agreement with the measured transient response of the apparent relative viscosity due to a sudden change in the shear rate

Determination of the turbulent viscosity inside a strongly heated rectangular jet: experimental and numerical studies; Determination de la viscosite turbulente dans un jet rectangulaire fortement chauffe: etudes experimentale et numerique

Energy Technology Data Exchange (ETDEWEB)

Sarh, B.; Gokalp, I.; Sanders, H. [Centre National de la Recherche Scientifique (CNRS), 45 - Orleans-la-Source (France)

1997-12-31

In the framework of the studies carried out by the LCSR on variable density flows and diffusion turbulent flames, this paper deals with the study of the influence of density variation on the characteristics of a heated rectangular turbulent jet emerging in a stagnant surrounding atmosphere and more particularly on the determination of turbulent viscosity. The dynamical field is measured using laser-Doppler anemometry while the thermal field is measured using cold wire anemometry. A numerical predetermination of the characteristics of this jet, based on a k-{epsilon} modeling, is carried out. (J.S.) 6 refs.

EXPERIMENTAL MEASUREMENT OF NANOFLUIDS THERMAL PROPERTIES

Directory of Open Access Journals (Sweden)

Adnan M. Hussein

2013-07-01

Full Text Available Solid particles dispersed in a liquid with sizes no larger than 100nm, known as nanofluids, are used to enhance Thermophysical properties compared to the base fluid. Preparations of alumina (Al2O3, titania (TiO2 and silica (SiO2 in water have been experimentally conducted in volume concentrations ranging between 1 and 2.5%. Thermal conductivity is measured by the hot wire method and viscosity with viscometer equipment. The results of thermal conductivity and viscosity showed an enhancement (0.5–20% and 0.5–60% respectively compared with the base fluid. The data measured agreed with experimental data of other researchers with deviation of less than 5%. The study showed that alumina has the highest thermal conductivity, followed silica and titania, on the other hand silica has the highest viscosity followed alumina and titania.

Interfacial thermal resistance between high-density polyethylene (HDPE) and sapphire

International Nuclear Information System (INIS)

Zheng Kun; Ma Yong-Mei; Wang Fo-Song; Zhu Jie; Tang Da-Wei

2014-01-01

To improve the thermal conductivity of polymeric composites, the numerous interfacial thermal resistance (ITR) inside is usually considered as a bottle neck, but the direct measurement of the ITR is hardly reported. In this paper, a sandwich structure which consists of transducer/high density polyethylene (HDPE)/sapphire is prepared to study the interface characteristics. Then, the ITRs between HDPE and sapphire of two samples with different HDPE thickness values are measured by time-domain thermoreflectance (TDTR) method and the results are ∼ 2 × 10 −7 m 2 ·K·W −1 . Furthermore, a model is used to evaluate the importance of ITR for the thermal conductivity of composites. The model's analysis indicates that reducing the ITR is an effective way of improving the thermal conductivity of composites. These results will provide valuable guidance for the design and manufacture of polymer-based thermally conductive materials. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Nano-viscosity of supercooled liquid measured by fluorescence correlation spectroscopy: Pressure and temperature dependence and the density scaling

Science.gov (United States)

Meier, G.; Gapinski, J.; Ratajczyk, M.; Lettinga, M. P.; Hirtz, K.; Banachowicz, E.; Patkowski, A.

2018-03-01

The Stokes-Einstein relation allows us to calculate apparent viscosity experienced by tracers in complex media on the basis of measured self-diffusion coefficients. Such defined nano-viscosity values can be obtained through single particle techniques, like fluorescence correlation spectroscopy (FCS) and particle tracking (PT). In order to perform such measurements, as functions of pressure and temperature, a new sample cell was designed and is described in this work. We show that this cell in combination with a long working distance objective of the confocal microscope can be used for successful FCS, PT, and confocal imaging experiments in broad pressure (0.1-100 MPa) and temperature ranges. The temperature and pressure dependent nano-viscosity of a van der Waals liquid obtained from the translational diffusion coefficient measured in this cell by means of FCS obeys the same scaling as the rotational relaxation and macro-viscosity of the system.

Chemically and Thermally Stable High Energy Density Silicone Composites, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Thermal energy storage systems with 300 -- 1000 kJ/kg energy density through either phase changes or chemical heat absorption are sought by NASA. This proposed...

Effect of viscosity on appetite and gastro-intestinal hormones

DEFF Research Database (Denmark)

Zijlstra, Nicolien; Mars, Monica; de Wijk, René A

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....../m(2)) participated in this cross-over study. Subjects received a fixed amount of a chocolate flavored milk-based liquid or semi-solid product similar in energy density and macronutrient composition. Before intake and 15, 30, 60 and 90 min thereafter, appetite was rated and blood was drawn to determine...... than the liquid. There was a significant product effect for fullness (p 0.03), desire to eat (p 0.04), appetite something sweet (p 0.002) and prospective consumption (p 0.0009). We observed no clear effect of viscosity on gastro-intestinal hormones. Only for desacyl ghrelin there was a significant...

Diffusivities and Viscosities of Poly(ethylene oxide) Oligomers †

KAUST Repository

Hong, Bingbing

2010-10-14

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

Viscosities of cesium vapor to 1,620 K and of liquid gallium to 1,800 K

International Nuclear Information System (INIS)

Tippelskirch, H. v.

1976-01-01

The viscosity of cesium at 1,620 K and 40 bar has been determined to 41 x 10 -6 (Pa x s) by the oscillating cup method. The saturated vapor density at 1,580 K could be derived from the viscosity measurements. The viscosity of liquid gallium has been determined from 370 K to 1,800 K. The experimental results have been compared with calculations based on the Enskog hard-sphere transport theory for dense fluids. (orig.) [de

Exploring inclusion complexes of ionic liquids with α- and β- cyclodextrin by NMR, IR, mass, density, viscosity, surface tension and conductance study

Science.gov (United States)

Barman, Biraj Kumar; Rajbanshi, Biplab; Yasmin, Ananya; Roy, Mahendra Nath

2018-05-01

The formation of the host-guest inclusion complexes of ionic liquids namely [BMIm]Cl and [HMIm]Cl with α-CD and β-CD were studied by means of physicochemical and spectroscopic methods. Conductivity and surface tension study were in good agreement with the 1H NMR and FT-IR studies which confirm the formation of the inclusion complexes. The Density and viscosity study also supported the formation of the ICs. Further the stoichiometry was determined 1:1 for each case and the association constants and thermodynamic parameters derived supported the most feasible formation of the [BMIm]Cl- β-CD inclusion complex.

Experimental and Theoretical Determination of Heavy Oil Viscosity Under Reservoir Conditions; ANNUAL

International Nuclear Information System (INIS)

Gabitto, Jorge; Barrufet, Maria

2002-01-01

The main objective of this research was to propose a simple procedure to predict heavy oil viscosity at reservoir conditions as a function of easily determined physical properties. This procedure will avoid costly experimental testing and reduce uncertainty in designing thermal recovery processes

The effect of low molecular weight multifunctional additives on heavy oil viscosity

Energy Technology Data Exchange (ETDEWEB)

Oldenburg, T.B.P.; Yarranton, H.W.; Larter, S.R. [Calgary Univ., AB (Canada)

2010-07-01

Crude oils contain many small multifunctional low molecular weight components that act as linking molecules between larger functionalized species. The linkage molecules have a significant impact on the flow properties of hydrocarbon systems. This study investigated the use of a low molecular weight multiheteroatom species (LMWMH) as a molecular Velcro linking high molecular weight components together. LMWMH species were added to Albertan bitumens and heavy oil, and their impact on viscosity was investigated. Results of the experimental studies were then compared with the effects of hydrocarbon solvents on similar samples. The LMWMH species included bifunctional species and analogous alkyl and aryl monoamines that acted as blocking molecules to hinder the association of larger petroleum species. Density and viscosity measurements were conducted. A correlation method was used to predict the viscosity of the solvent-diluted heavy oil and bitumen samples. The study showed that of the tested additives, only aniline demonstrated an additional viscosity-reducing effect. The aniline inhibited asphaltene association and is a promising candidate for enhanced in-situ bitumen viscosity reduction. 23 refs., 4 tabs.

Shear viscosity of the quark-gluon plasma in a kinetic theory approach

International Nuclear Information System (INIS)

Puglisi, A.; Plumari, S.; Scardina, F.; Greco, V.

2014-01-01

One of the main results of heavy ions collision (HIC) at relativistic energy experiments is the very small shear viscosity to entropy density ratio of the Quark-Gluon Plasma, close to the conjectured lower bound η/s=1/4π for systems in the infinite coupling limit. Transport coefficients like shear viscosity are responsible of non-equilibrium properties of a system: Green-Kubo relations give us an exact expression to compute these coefficients. We compute shear viscosity numerically using Green-Kubo relation in the framework of Kinetic Theory solving the relativistic transport Boltzmann equation in a finite box with periodic boundary conditions. We investigate a system of particles interacting via anisotropic and energy dependent cross-section in the range of temperature of interest for HIC. Green-Kubo results are in agreement with Chapman-Enskog approximation while Relaxation Time approximation can underestimates the viscosity of a factor 2. The correct analytic formula for shear viscosity can be used to develop a transport theory with a fixed η/s and have a comparison with physical observables like elliptic flow

Structure of the solar nebula, growth and decay of magnetic fields and effects of magnetic and turbulent viscosities on the nebula

International Nuclear Information System (INIS)

Hayashi, Chushiro

1982-01-01

First, distributions of surface densities of dust materials and gases in a preplanetary solar nebula, which give a good fit to the distribution of the planetary mass, are presented and the over-all structure of this nebula, which is in thermal and gravitational equilibrium, is studied. Second, in order to see magnetic effect on the structure, electric conductivity of a gas ionized by cosmic rays and radioactivities contained in dust grains is estimated for each region of the nebula and, then, the growth and decay of seed magnetic fields, which are due to differential rotation of the nebula and to the Joule dissipation, respectively, are calculated. The results indicate that, in regions of the terrestrial planets, magnetic fields decay much faster than they grow and magnetic effects can be ignored, except for the outermost layers of very low density. This is not the case for regions of Uranus and Neptune where magnetic fields can be amplified to considerable extents. Third, the transport of angular momentum due to magnetic and mechanical turbulent viscosities and the resultant redistribution of surface density in the nebula are investigated. The results show that the density redistribution occurs, in general, in a direction to attain a distribution of surface density which has nearly the same ν-dependence as that obtained from the present distribution of the planetary mass. This redistribution seems to be possible if it occurs at a formation stage of the nebula where the presence of large viscosities is expected. Finally, a comment is given on the initial condition of a collapsing interstellar cloud from which the solar nebula is formed at the end of the collapse. (author)

Effect of Water Glass Modification on Its Viscosity and Wettability of Quartz Grains

Directory of Open Access Journals (Sweden)

A. Kmita

2012-09-01

Full Text Available The aim of the present study was to develop a modifier for water glass. The method of thermal generation of metal oxide nanoparticleswas adapted and used in the research. Nanoparticles of ZnO from the thermal decomposition of basic zinc carbonate were used. A methodfor the modifier introduction was developed, and the effect of modifier content and organic solvent type on the physico-chemicalproperties of binder (viscosity and quartz wettability was determined. Binder viscosity was examined from the flow curves plotted with the help of a RHEOTEST 2 rotational rheometer equipped with proper software. Quartz wettability was determined examining timerelated changes in the value of the contact angle in a quartz-binder system, until full stabilisation of the angle value has been achieved.Binder modification was carried out on sodium water glass designated as R"145". The water glass modifiers were suspensions of ZnOnanoparticles in propanol and methanol at a fixed concentration of c = 0.3 M and with the size of nanoparticles comprised in a range of. Water glass modification with the suspensions of ZnO nanoparticles in methanol and propanol showed the effect ofmodifier on the water glass viscosity and quartz wettability. This effect depends on the type of alcohol used. The ZnO suspension inpropanol (alcohol with a longer hydrocarbon chain affects more strongly the viscosity of binder and quartz wettability than the methanol suspension.

Effect of Water Glass Modification on Its Viscosity and Wettability of Quartz Grains

Directory of Open Access Journals (Sweden)

Kmita A.

2012-09-01

Full Text Available The aim of the present study was to develop a modifier for water glass. The method of thermal generation of metal oxide nanoparticles was adapted and used in the research. Nanoparticles of ZnO from the thermal decomposition of basic zinc carbonate were used. A method for the modifier introduction was developed, and the effect of modifier content and organic solvent type on the physico-chemical properties of binder (viscosity and quartz wettability was determined. Binder viscosity was examined from the flow curves plotted with the help of a RHEOTEST 2 rotational rheometer equipped with proper software. Quartz wettability was determined examining timerelated changes in the value of the contact angle in a quartz-binder system, until full stabilisation of the angle value has been achieved. Binder modification was carried out on sodium water glass designated as R"145". The water glass modifiers were suspensions of ZnO nanoparticles in propanol and methanol at a fixed concentration of c = 0.3 M and with the size of nanoparticles comprised in a range of . Water glass modification with the suspensions of ZnO nanoparticles in methanol and propanol showed the effect of modifier on the water glass viscosity and quartz wettability. This effect depends on the type of alcohol used. The ZnO suspension in propanol (alcohol with a longer hydrocarbon chain affects more strongly the viscosity of binder and quartz wettability than the methanol suspension

Influence of dispersing additives and blend composition on stability of marine high-viscosity fuels

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Т. Н. Митусова

2017-12-01

Full Text Available The article offers a definition of the stability of marine high-viscosity fuel from the point of view of the colloid-chemical concept of oil dispersed systems. The necessity and importance of the inclusion in the current regulatory requirements of this quality parameter of high-viscosity marine fuel is indicated. The objects of the research are high-viscosity marine fuels, the basic components of which are heavy oil residues: fuel oil that is the atmospheric residue of oil refining and viscosity breaking residue that is the product of light thermal cracking of fuel oil. As a thinning agent or distillate component, a light gas oil was taken from the catalytic cracking unit. The stability of the obtained samples was determined through the xylene equivalent index, which characterizes the stability of marine high-viscosity fuel to lamination during storage, transportation and operation processes. To improve performance, the resulting base compositions of high-viscosity marine fuels were modified by introducing small concentrations (0.05 % by weight of stabilizing additives based on oxyethylated amines of domestic origin and alkyl naphthalenes of foreign origin.

Thermal turbulent convection: thermal plumes and fluctuations

International Nuclear Information System (INIS)

Gibert, M.

2007-10-01

In this study we investigate the phenomenon of thermal turbulent convection in new and unprecedented ways. The first system we studied experimentally is an infinite vertical channel, where a constant vertical mean gradient of temperature exists. Inside this channel the average mass flux is null. The results obtained from our measurements reveal that the flow is mainly inertial; indeed the dissipative coefficients (here the viscosity) play a role only to define a coherence length L. This length is the distance over which the thermal plumes can be considered as 'free falling' objects. The horizontal transport, of heat and momentum, is entirely due to fluctuations. The associated 'mixing length' is small compared to the channel width. In the other hand, the vertical heat transport is due to coherent structures: the heat plumes. Those objects were also investigated in a Lagrangian study of the flow in the bulk of a Rayleigh-Benard cell. The probe, which has the same density as the fluid used in this experiment, is a sphere of 2 cm in diameter with embarked thermometers and radio-emitter. The heat plumes transport it, which allows a statistical study of such objects. (author)

A fully discrete energy stable scheme for a phase filed moving contact line model with variable densities and viscosities

KAUST Repository

Zhu, Guangpu

2018-01-26

In this paper, a fully discrete scheme which considers temporal and spatial discretizations is presented for the coupled Cahn-Hilliard equation in conserved form with the dynamic contact line condition and the Navier-Stokes equation with the generalized Navier boundary condition. Variable densities and viscosities are incorporated in this model. A rigorous proof of energy stability is provided for the fully discrete scheme based on a semi-implicit temporal discretization and a finite difference method on the staggered grids for the spatial discretization. A splitting method based on the pressure stabilization is implemented to solve the Navier-Stokes equation, while the stabilization approach is also used for the Cahn-Hilliard equation. Numerical results in both 2-D and 3-D demonstrate the accuracy, efficiency and decaying property of discrete energy of the proposed scheme.

Thermal Stress Effect on Density Changes of Hemp Hurds Composites

Science.gov (United States)

Schwarzova, Ivana; Cigasova, Julia; Stevulova, Nadezda

2016-12-01

The aim of this article is to study the behavior of prepared biocomposites based on hemp hurds as a filling agent in composite system. In addition to the filler and water, an alternative binder, called MgO-cement was used. For this objective were prepared three types of samples; samples based on untreated hemp hurds as a referential material and samples based on chemically (with NaOH solution) and physically (by ultrasonic procedure) treated hemp hurds. The thermal stress effect on bulk density changes of hemp hurds composites was monitored. Gradual increase in temperature led to composites density reduction of 30-40 %. This process is connected with mass loss of the adsorbed moisture and physically bound water and also with degradation of organic compounds present in hemp hurds aggregates such as pectin, hemicelluloses and cellulose. Therefore the changes in the chemical composition of treated hemp hurds in comparison to original sample and its thermal decomposition were also studied.

Thermal Stress Effect on Density Changes of Hemp Hurds Composites

Directory of Open Access Journals (Sweden)

Schwarzova Ivana

2016-12-01

Full Text Available The aim of this article is to study the behavior of prepared biocomposites based on hemp hurds as a filling agent in composite system. In addition to the filler and water, an alternative binder, called MgO-cement was used. For this objective were prepared three types of samples; samples based on untreated hemp hurds as a referential material and samples based on chemically (with NaOH solution and physically (by ultrasonic procedure treated hemp hurds. The thermal stress effect on bulk density changes of hemp hurds composites was monitored. Gradual increase in temperature led to composites density reduction of 30-40 %. This process is connected with mass loss of the adsorbed moisture and physically bound water and also with degradation of organic compounds present in hemp hurds aggregates such as pectin, hemicelluloses and cellulose. Therefore the changes in the chemical composition of treated hemp hurds in comparison to original sample and its thermal decomposition were also studied.

Detecting protein folding by thermal fluctuations of microcantilevers.

Directory of Open Access Journals (Sweden)

Romina Muñoz

Full Text Available The accurate characterization of proteins in both their native and denatured states is essential to effectively understand protein function, folding and stability. As a proof of concept, a micro rheological method is applied, based on the characterization of thermal fluctuations of a micro cantilever immersed in a bovine serum albumin solution, to assess changes in the viscosity associated with modifications in the protein's structure under the denaturant effect of urea. Through modeling the power spectrum density of the cantilever's fluctuations over a broad frequency band, it is possible to implement a fitting procedure to accurately determine the viscosity of the fluid, even at low volumes. Increases in viscosity during the denaturant process are identified using the assumption that the protein is a hard sphere, with a hydrodynamic radius that increases during unfolding. This is modeled accordingly through the Einstein-Batchelor formula. The Einstein-Batchelor formula estimates are verified through dynamic light scattering, which measures the hydrodynamic radius of proteins. Thus, this methodology is proven to be suitable for the study of protein folding in samples of small size at vanishing shear stresses.

A Simple BODIPY-Based Viscosity Probe for Imaging of Cellular Viscosity in Live Cells

Directory of Open Access Journals (Sweden)

Dongdong Su

2016-08-01

Full Text Available Intracellular viscosity is a fundamental physical parameter that indicates the functioning of cells. In this work, we developed a simple boron-dipyrromethene (BODIPY-based probe, BTV, for cellular mitochondria viscosity imaging by coupling a simple BODIPY rotor with a mitochondria-targeting unit. The BTV exhibited a significant fluorescence intensity enhancement of more than 100-fold as the solvent viscosity increased. Also, the probe showed a direct linear relationship between the fluorescence lifetime and the media viscosity, which makes it possible to trace the change of the medium viscosity. Furthermore, it was demonstrated that BTV could achieve practical applicability in the monitoring of mitochondrial viscosity changes in live cells through fluorescence lifetime imaging microscopy (FLIM.

Dynamic viscosity of polymer solutions

Energy Technology Data Exchange (ETDEWEB)

Peterlin, A

1982-03-01

The dynamic viscosity investigation of solutions of long chain polymers in very viscous solvents has definitely shown the existence of the low and high frequency plateau with the gradual transition between them. In both extreme cases the extrapolation of the measured Newtonian viscosities of the plateaus to the infinite dilution yields the limiting intrinsic viscosities. Such a behavior is expected from the dynamic intrinsic viscosity of the necklace model of the linear polymer with finite internal viscosity. The plateau at low frequency shows up in any model of polymer solution. This work shows the constant dynamic intrinsic viscosity in both extreme cases is well reproducible by the necklace model with the internal viscosity acting only between the beads on the same link. 20 references.

Thermal Cracking to Improve the Qualification of the Waxes

Science.gov (United States)

He, B.; Agblevor, F. A.; Chen, C. G.; Feng, J.

2018-05-01

Thermal cracking of waxes at mild conditions (430-500°C) has been reconsidered as a possible refining technology for the production of fuels and chemicals. In this study, the more moderate thermal cracking was investigated to process Uinta Basin soft waxes to achieve the required pour point so that they can be pumped to the refineries. The best thermal cracking conditions were set 420°C and 20 minutes. The viscosity and density of the final liquid product were respectively achieved as 2.63 mP•s and 0.784 g/cm3 at 40°C. The result of FT-IR analysis of the liquid product indicated that the unsaturated hydrocarbons were produced after thermal cracking, which was corroborated by the 13C NMR spectrum. The GC analysis of the final gas product indicated that the hydrogen was produced; the dehydrogenation reaction was also proved by the elemental analysis and HHV results. The pour point of the final liquid product met the requirement.

Empirical equations for viscosity and specific heat capacity determination of paraffin PCM and fatty acid PCM

Science.gov (United States)

Barreneche, C.; Ferrer, G.; Palacios, A.; Solé, A.; Inés Fernández, A.; Cabeza, L. F.

2017-10-01

Phase change materials (PCM) used in thermal energy storage (TES) systems have been presented, over recent years, as one of the most effective options in energy storage. Paraffin and fatty acids are some of the most used PCM in TES systems, as they have high phase change enthalpy and in addition they do not present subcooling nor hysteresis and have proper cycling stability. The simulations and design of TES systems require the knowledge of the thermophysical properties of PCM. Thermal conductivity, viscosity, specific heat capacity (Cp) can be experimentally determined, but these are material and time consuming tasks. To avoid or to reduce them, and to have reliable data without the need of experimentation, thermal properties can be calculated by empirical equations. In this study, five different equations are given to calculate the viscosity and specific heat capacity of fatty acid PCM and paraffin PCM. Two of these equations concern, respectively, the empirical calculation of the viscosity and liquid Cp of the whole paraffin PCM family, while the other three equations presented are for the corresponding calculation of viscosity, solid Cp, liquid Cp of the whole fatty acid family of PCM. Therefore, this study summarize the work performed to obtain the main empirical equations to measure the above mentioned properties for whole fatty acid PCM family and whole paraffin PCM family. Moreover, empirical equations have been obtained to calculate these properties for other materials of these PCM groups and these empirical equations can be extrapolated for PCM with higher or lower phase change temperatures within a lower relative error 4%.

Anharmonic thermal vibrations of be metal found in the MEM nuclear density map

International Nuclear Information System (INIS)

Takata, Masaki; Sakata, Makoto; Larsen, F.K.; Kumazawa, Shintaro; Iversen, B.B.

1993-01-01

A direct observation of the thermal vibrations of Be metal was performed by the Maximum Entropy Method (MEM) using neutron single crystal data. In the previous study, the existence of the small but significant cubic anharmonicity of Be has been found by the conventional least squares refinement of the observed structure factors [Larsen, Lehmann and Merisalo (1980) Acta Cryst. A36, 159-163]. In the present study, the same data were used for the MEM analysis which are comprised of 48 reflections up to sinθ/λ = 1.41A -1 in order to obtain the high resolution nuclear density of Be without using any thermal vibrational model. It was directly visible in the MEM map that not only the cubic terms but also quartic anharmonicities exist in the thermal vibrations of Be nuclei. In order to evaluate thermal parameters of Be including anharmonic terms quantitatively, the least squares refinement of the effective one-particle potential (OPP) parameters up to quartic term was carried out by using the MEM nuclear densities around atomic sites as the data set to be fitted. It was found that the present treatment has a great advantage to decide the most appropriate model of OPP by visually comparing the model with MEM density map. As a result of the least squares refinement, the anharmonic thermal parameters are obtained as α 33 = -0.340(5)[eV/A 3 ], α 40 = 0, β 20 = 9.89(1)[eV/A 4 ] and γ 00 = 0. No other anharmonic term was significant. (author)

Quantitative analysis of the thermal damping of coherent axion oscillations

International Nuclear Information System (INIS)

Turner, M.S.

1985-01-01

Unruh and Wald have recently discussed a new mechanism for damping coherent axion oscillations, ''thermal damping,'' which occurs due to the temperature dependence of the axion mass and neutrino viscosity. We investigate the effect quantitatively and find that the present energy density in axions can be written as rho/sub a/ = rho/sub a0//(1+J/sub UW/), where rho/sub a/0 is what the axion energy density would be in the absence of the thermal-damping effect and J/sub UW/ is an integral whose integrand depends upon (dm/sub a//dT) 2 . As a function of f(equivalentPeccei-Quinn symmetry-breaking scale) J/sub UW/ achieves its maximum value for f/sub PQ/approx. =3 x 10 12 GeV; unless the axion mass turn-on is very sudden, Vertical Bar(T/m/sub a/)(dm/sub a//dT)Vertical Bar>>1, J/sub UW/ is <<1, implying that this damping mechanism is not significant

Application of the DTM to Nonlinear Cases Arising in Fluid Flows with Variable Viscosity

DEFF Research Database (Denmark)

Barari, Amin; Rahimi, M; Hosseini, M.J

2012-01-01

This paper employs the differential transformation method to investigate two nonlinear ordinary differential systems for plane coquette flow having variable viscosity and thermal conductivity. The concept of differential transformation is briefly introduced, and then differential transformation m...

Experimental data of thermal cracking of soybean oil and blends with hydrogenated fat

Directory of Open Access Journals (Sweden)

R.F. Beims

2018-04-01

Full Text Available This article presents the experimental data on the thermal cracking of soybean oil and blends with hydrogenated fat. Thermal cracking experiments were carried out in a plug flow reactor with pure soybean oil and two blends with hydrogenated fat to reduce the degree of unsaturation of the feedstock. The same operational conditions was considered. The data obtained showed a total aromatics content reduction by 14% with the lowest degree of unsaturation feedstock. Other physicochemical data is presented, such as iodine index, acid index, density, kinematic viscosity. A distillation curve was carried out and compared with the curve from a petroleum sample.

Using Quartz Crystal Microbalance for Field Measurement of Liquid Viscosities

Directory of Open Access Journals (Sweden)

Qingsong Bai

2016-01-01

Full Text Available The field measurement of liquid viscosities, especially the high viscous liquids, is challenging and often requires expensive equipment, long processing time, and lots of reagent. We use quartz crystal microbalances (QCMs operating in solution which are also sensitive to the viscosity and density of the contacting solution. QCMs are typically investigated for sensor applications in which one surface of QCM completely immersed in Newtonian liquid, but the viscous damping in liquids would cause not only large frequency shifts but also large losses in the quality factor Q leading to instability and even cessation of oscillation. A novel mass-sensitivity-based method for field measurement of liquid viscosities using a QCM is demonstrated in this paper and a model describing the influence of the liquid properties on the oscillation frequency is established as well. Two groups of verified experiments were performed and the experimental results show that the presented method is effective and possesses potential applications.

Thermal expansion and density measurements of molten and solid materials at high temperatures by the gamma attenuation technique

International Nuclear Information System (INIS)

Drotning, W.D.

1979-05-01

An apparatus is described for the measurement of the density and thermal expansion of molten materials to 3200 0 K using the gamma attenuation technique. The precision of the experimental technique was analytically examined for both absolute and relative density determinations. Three analytical expressions used to reduce data for liquid density determinations were evaluated for their precision. Each allows use of a different set of input data parameters, which can be chosen based on experimental considerations. Using experimentally reasonable values for the precision of the parameters yields a similar resultant density precision from the three methods, on the order of 0.2%. The analytical method for measurements of the linear thermal expansion of solids by the gamma method is also described. To demonstrate the use of the technique on reasonably well-characterized systems, data are presented for (1) the density and thermal expansion of molten tin, lead, and aluminum to 1300 0 K, (2) the thermal expansion of solid aluminum to the melting point, and (3) the thermal expansion of a low melting point glass through the transition temperature and melting region. The data agree very well with published results using other methods where such published data exist

THE STABILITY OF OPTICALLY THIN REACTING PLASMAS: EFFECTS OF THE BULK VISCOSITY

International Nuclear Information System (INIS)

Ibanez S, Miguel H.

2009-01-01

The thermochemical stability of reacting plasmas is analyzed by taking into account the change in the thermodynamical equilibrium values during the fluctuation. This shift in the equilibrium produces two main effects: a change in the four instability criteria for reacting gases resulting when the above effect is neglected and adds a fifth instability criterion due to the fact that the corresponding secular equation becomes a fifth-order polynomial. The above results are applied to several plasma models, in particular, to a photoionized hydrogen plasma for which the bulk viscosity can be more important than the dynamic viscosity and the thermometric conductivity. Therefore, the bulk viscosity may quench thermochemical instabilities were the thermal conduction is unable of stabilizing. This occurs for low values of the photoionizing energy E. The implications of the above results in explaining the formation of clump structures in different regions of the interstellar medium are outlined.

[Relations between plasma-erythrocyte viscosity factors and ESR].

Science.gov (United States)

Cortinovis, A; Crippa, A; Crippa, M; Bosoni, T; Moratti, R

1992-09-01

The ESR is usually put in relationship: to the real density of the RBCs (erythrocytes) (difference between the RBC specific gravity and the plasma one), and to the resistance that the RBCs meet moving in a medium, which is due to the plasma viscosity and to the total external RBC surface. When the RBCs take shape of aggregates, their external surface is decreased and ESR increases. The most important plasma factor causing changes in ESR is the fibrinogen level followed by the plasma globulins and by the products arising from the tissue damage. The resistance that the RBCs meet moving in the plasma is well expressed by the measurement of the plasma-RBC viscosity considering that is inclusive of both factors that are the plasma viscosity and the external RBC surface. The plasma-RBC viscosity is the resultant of several factors: Fa = Fb - Fe - Fs - Fm, were: Fa is the resultant, Fb the attracting forces due to the proteic macromolecules, Fe the repulsing forces due the negative charges. Fs the repulsing forces due to the shear-stress, Fm the force which opposes itself against the surface tension of the aggregation; it depends on the RBC morphology and on the RBC rigidity. The ESR has been recently used like an index of the RBC aggregation. The Authors study the relationship between several hemorheological parameters and the ESR in infective and inflammatory processes.(ABSTRACT TRUNCATED AT 250 WORDS)

Produção de farinha instantânea de mandioca: efeito das condições de extrusão sobre as propriedades térmicas e de pasta = Cassava instant flour: effect of extrusion conditions on thermal and viscosity properties

Directory of Open Access Journals (Sweden)

Beatriz Helena Borges Lustosa

2009-04-01

Full Text Available Com o avanço de tecnologias, existe a possibilidade da introdução, no mercado, de farinhas de mandioca diferenciadas, como as farinhas instantâneas, sendo esta uma alternativa de grande interesse para as indústrias processadoras de mandioca. Este trabalho teve por objetivo avaliar o efeito da temperatura de extrusão, umidade da farinha e rotação da rosca sobre as propriedades térmicas e de pasta de farinhas de mandioca extrusadas. Os resultados obtidos mostraram efeitos significativos da rotação da rosca sobre a viscosidadeinicial, pico e quebra de viscosidade. O pico de viscosidade foi influenciado pelos três parâmetros de processo, não sendo observados efeitos significativos dos parâmetros sobre a viscosidade final e tendência a retrogradação. As propriedades térmicas das farinhasextrusadas não apresentaram entalpia de gelatinização residual.With the advancement of technology, there is the possibility ofintroduction of differentiated flours, such as cassava instant flour. This alternative has generated great interest from the cassava processing industries. This study aimed to assess the effect of extrusion temperature, moisture content and screw speed on the thermal and viscosity properties of extruded cassava flour. The results showed significant effects of process parameters on the viscosity properties, with effect of screw speed on cold viscosity,viscosity peak and breakdown. The viscosity peak was influenced by the three parameters of extrusion process. No significant effects of operational conditions were observed on the final viscosity and retrogradation. The thermal properties of extruded cassava flours showed no residual enthalpy of gelatinization.

Excess molar volumes, viscosities, and speeds of sound of the ternary mixture {l_brace}1-heptanol (1)+trichloroethylene (2)+methylcyclohexane (3){r_brace} at T=298.15K

Energy Technology Data Exchange (ETDEWEB)

Iloukhani, Hossein [Department of Chemistry, Faculty of Science, University of Bu-Ali Sina, Hamedan 65174 (Iran, Islamic Republic of)]. E-mail: iloukhani@basu.ac.ir; Samiey, Babak [Department of Chemistry, Faculty of Science, University of Lorestan, Khoramabad (Iran, Islamic Republic of)

2007-02-15

Densities ({rho}), viscosities ({eta}), and speeds of sound (u) of the ternary mixture (1-heptanol+trichloroethylene+methylcyclohexane) and the involved binary mixtures (1-heptanol+trichloroethylene) (1-heptanol+methylcyclohexane), and (trichloroethylene+methylcyclohexane) at 298.15K were measured over the whole composition range. The data obtained are used to calculate excess molar volumes (V{sup E}), excess isobaric thermal expansivity ({alpha}{sup E}), viscosity deviations ({delta}{eta}), excess Gibbs free energies of activation of viscous flow ({delta}G{sup *E}), and excess isentropic compressibilities ({kappa}{sub S}{sup E}) of the binary and ternary mixtures. The data of the binary systems were fitted to the Redlich-Kister equation while the best correlation method for the ternary system was found using the Nagata equation. Viscosities, speeds of sound and isentropic compressibilities of the binary and ternary mixtures have been correlated by means of several empirical and semi-empirical equations. The best correlation method for viscosities of binary systems is found using the Iulan et al. equation and for the ternary system using the McAllister equation. The best correlation method for speeds of sound and isentropic compressibilities of the binary systems is found using the IMR and for the ternary system using the IMR and JR.

Effect of viscosity on seismic response of waste storage tanks

International Nuclear Information System (INIS)

Tang, Yu; Uras, R.A.; Chang, Yao-Wen.

1992-06-01

The dynamic response of liquid-storage tanks subjected to harmonic excitations and earthquake ground motions has been studied. A rigid tank of negligible mass, rigidly supported at the base having a diameter of 50 ft. and fluid height of 20.4 ft. was used in the computer analysis. The liquid is assumed to have a density of 1.5 g/ml. Viscosity values, μ = 60, 200, 100, and 10,000 cP, were used in the numerical analyses to study the effects of viscosity on sloshing wave height, impulsive and convective pressure on the tank wall, base shear and base moments. Harmonic excitations as well as earthquake ground motions were used as input motions. The harmonic excitations used in the analyses covers a wide range of frequencies, including both the resonant and non-resonant frequencies. Two earthquake motions were used. One matches the Newmark-Hall median response spectrum and is anchored at 0.24 g for a rock site with a damping of 2% and a time duration of 10 s. The other is the 1978 Tabas earthquake which had a peak ZPA of 0.81 g and a time duration of 29 s. A small tank, about 1/15 the size of the typical waste storage tank, was used in the harmonic excitation study to investigate the effect of viscosity on the response of liquid-storage tanks and how the viscosity effect is affected by the size of the storage tank. The results of this study show that for the typical waste storage tank subjected to earthquake motions, the effect of viscosity on sloshing wave height and impulsive and convective pressures is very small and can be neglected. For viscosity effect to become noticeable in the response of the typical waste storage tank, the waste viscosity must be greater than 10,000 cP. This value is far greater than the estimated viscosity value of the high level wastes, which may range from 60 to 200 cP for some tanks

Calculation of thermal-diffusion coefficients from plane-wave fluctuations in the heat energy density

International Nuclear Information System (INIS)

Palmer, B.J.

1994-01-01

A method to calculate the thermal diffusivity D T from spontaneous fluctuations in the local heat energy density is presented. Calculations of the thermal diffusivity are performed for the Lennard-Jones fluid, carbon dioxide, and water. The results for the Lennard-Jones fluid are in agreement with calculations of the thermal conductivity using Green-Kubo relations and nonequilibrium molecular-dynamics techniques. The results for carbon dioxide and water give thermal diffusivities within a factor of 2 of the experimental values

Anisotropic cosmological models with bulk viscosity and particle ...

Indian Academy of Sciences (India)

4.1.3 Ideal gas. In the case of an ideal gas. = 0 and pc = 0. Then eq. (2) becomes. ˙η + 3ηH = 0. (69). Equation (69), on integration gives η = η1t. −3/n,. (70) where η1 is an integrating constant. Equation (69) is the expression for particle creation density. This model has only bulk viscosity and bulk viscous stress is obtained as.

Shear viscosity and out of equilibrium dynamics

CERN Document Server

El, Andrej; Xu, Zhe; Greiner, Carsten

2009-01-01

Using the Grad's method we calculate the entropy production and derive a formula for the second order shear viscosity coefficient in a one-dimensionally expanding particle system, which can also be considered out of chemical equilibrium. For a one-dimensional expansion of gluon matter with Bjorken boost invariance the shear tensor and the shear viscosity to entropy density ratio $\\eta/s$ are numerically calculated by an iterative and self-consistent prescription within the second order Israel-Stewart hydrodynamics and by a microscopic parton cascade transport theory. Compared with $\\eta/s$ obtained using the Navier-Stokes approximation, the present result is about 20% larger at a QCD coupling $\\alpha_s \\sim 0.3$(with $\\eta/s\\approx 0.18$) and is a factor of 2-3 larger at a small coupling $\\alpha_s \\sim 0.01$. We demonstrate an agreement between the viscous hydrodynamic calculations and the microscopic transport results on $\\eta/s$, except when employing a small $\\alpha_s$. On the other hand, we demonstrate th...

Densities and viscosities of binary mixtures of {l_brace}dimethylsulfoxide+aliphatic lower alkanols (C{sub 1}-C{sub 3}){r_brace} at temperatures from T=303.15K to T=323.15K

Energy Technology Data Exchange (ETDEWEB)

Bhuiyan, M.M.H. [Department of Chemistry, University of Dhaka, Dhaka 1000 (Bangladesh)]. E-mail: bhuiyan_du@yahoo.com; Ferdaush, J. [Youngone Central Laboratory, Youngone Hi-Tech Sportswear Ind. Ltd, Dhaka Export Processing Zone, Savar, Dhaka (Bangladesh); Uddin, M.H. [Department of Applied Physics and Chemistry, University of Electro-Communications, 1-5-1 Chofu-shi, Chofugawaka, Tokyo (Japan)

2007-05-15

Densities and viscosities for dimethylsulfoxide (DMSO) with methanol, ethanol, 1-propanol, and 2-propanol have been measured as a function of mole fraction at T=(303.15, 308.15, 313.15, 318.15, and 323.15)K and atmospheric pressure. From the measurements, excess molar volumes (V{sub m}{sup E}), excess viscosities ({eta}{sup E}), and Grunberg and Nissan interaction parameters ({epsilon}) have been calculated. The excess parameters are fitted to a Redlich-Kister equation. Excess molar volumes (V{sub m}{sup E}) are negative for (DMSO+methanol, +ethanol) systems throughout the whole range of composition. The (DMSO+1-propanol) system shows both positive and negative excess molar volumes and (DMSO+2-propanol) shows positive excess molar volume, hardly any negative value is observed in alcohol rich-region. The excess viscosities and interaction parameters of all the mixtures are negative except for the (DMSO+methanol) system which is positive.

A relationship between solvent viscosity and biomolecule picosecond thermal fluctuations

International Nuclear Information System (INIS)

Cornicchi, E.; De Francesco, A.; Marconi, M.; Onori, G.; Paciaroni, A.

2008-01-01

Through elastic neutron scattering measurements, we investigated the picosecond dynamics of DNA in the hydrated powder state or embedded in glycerol glassy matrix from 20 K to 300 K. We calculated the relaxational contribution of the mean square displacements (MSD) of DNA hydrogen atoms. We found the existence of a linear relationship between the inverse of the biomolecule relaxational MSD and the logarithm of the bulk viscosity of the surrounding environment. From the comparison with the case of lysozyme in the same environments, for which the validity of the relationship was already verified, possible differences and analogies concerning the biomolecule-to-solvent dynamical coupling can be stressed

Gyro-viscosity and linear dispersion relations in pair-ion magnetized plasmas

Energy Technology Data Exchange (ETDEWEB)

Kono, M. [Faculty of Policy Studies, Chuo University, Tokyo 192-0393 (Japan); Vranjes, J. [Instituto de Astrofisica de Canarias, Tenerife E38205 (Spain); Departamento de Astrofisica, Universidad de La Laguna, Tenerife E38205 (Spain)

2015-11-15

A fluid theory has been developed by taking account of gyro-viscosity to study wave propagation characteristics in a homogeneous pair-ion magnetized plasma with a cylindrical symmetry. The exact dispersion relations derived by the Hankel-Fourier transformation are shown comparable with those observed in the experiment by Oohara and co-workers. The gyro-viscosity is responsible for the change in propagation characteristics of the ion cyclotron wave from forward to backward by suppressing the effect of the thermal pressure which normally causes the forward nature of dispersion. Although the experiment has been already explained by a kinetic theory by the present authors, the kinetic derivations are so involved because of exact particle orbits in phase space, finite Lamor radius effects, and higher order ion cyclotron resonances. The present fluid theory provides a simple and transparent structure to the dispersion relations since the gyro-viscosity is renormalized into the ion cyclotron frequency which itself indicates the backward nature of dispersion. The usual disadvantage of a fluid theory, which treats only fundamental modes of eigen-waves excited in a system and is not able to describe higher harmonics that a kinetic theory does, is compensated by simple derivations and clear picture based on the renormalization of the gyro-viscosity.

Barkhausen jumps and magnetic viscosity in NdFeB magnets

Energy Technology Data Exchange (ETDEWEB)

LoBue, M. [Instituto Elettrotecnico Nazionale Galileo Ferraris, Strada delle Cacce 91, 10135 Torino (Italy)]. E-mail: lobue@ien.it; Basso, V. [Instituto Elettrotecnico Nazionale Galileo Ferraris, Strada delle Cacce 91, 10135 Torino (Italy); Beatrice, G. [Instituto Elettrotecnico Nazionale Galileo Ferraris, Strada delle Cacce 91, 10135 Torino (Italy); Bertotti, C. [Instituto Elettrotecnico Nazionale Galileo Ferraris, Strada delle Cacce 91, 10135 Torino (Italy); Durin, G. [Instituto Elettrotecnico Nazionale Galileo Ferraris, Strada delle Cacce 91, 10135 Torino (Italy); Sasso, C.P. [Instituto Elettrotecnico Nazionale Galileo Ferraris, Strada delle Cacce 91, 10135 Torino (Italy)

2005-04-15

We present the analysis of Barkhausen noise measured on a Nd-Fe-B sintered sample during viscosity experiments at constant applied field H. The measured jump sizes give direct evidence that the dominant magnetization process is the reversal of a single or of a small group of grains. The Barkhausen noise average amplitude allows to evaluate the viscosity coefficient S and the related activation volume v{sub a}. We found v{sub a}{sup 1/3} {approx} 6nm which is comparable to the domain wall width, in agreement with previous interpretations. The Barkhausen jump sizes show a power-law distribution independent of the time elapsed from the beginning of the relaxation. This fact validates the interpretation of the observed relaxations as due to thermal activation over a distribution of energy barriers.

Barkhausen jumps and magnetic viscosity in NdFeB magnets

International Nuclear Information System (INIS)

LoBue, M.; Basso, V.; Beatrice, G.; Bertotti, C.; Durin, G.; Sasso, C.P.

2005-01-01

We present the analysis of Barkhausen noise measured on a Nd-Fe-B sintered sample during viscosity experiments at constant applied field H. The measured jump sizes give direct evidence that the dominant magnetization process is the reversal of a single or of a small group of grains. The Barkhausen noise average amplitude allows to evaluate the viscosity coefficient S and the related activation volume v a . We found v a 1/3 ∼ 6nm which is comparable to the domain wall width, in agreement with previous interpretations. The Barkhausen jump sizes show a power-law distribution independent of the time elapsed from the beginning of the relaxation. This fact validates the interpretation of the observed relaxations as due to thermal activation over a distribution of energy barriers

Bianchi type-VIh string cloud cosmological models with bulk viscosity

Science.gov (United States)

Tripathy, Sunil K.; Behera, Dipanjali

2010-11-01

String cloud cosmological models are studied using spatially homogeneous and anisotropic Bianchi type VIh metric in the frame work of general relativity. The field equations are solved for massive string cloud in presence of bulk viscosity. A general linear equation of state of the cosmic string tension density with the proper energy density of the universe is considered. The physical and kinematical properties of the models have been discussed in detail and the limits of the anisotropic parameter responsible for different phases of the universe are explored.

Influence of Temperature and Storing Time on Selected Red Wine Physical Properties

Directory of Open Access Journals (Sweden)

Peter Hlaváč

2016-01-01

Full Text Available Presented article is focused on red wine rheological and thermal properties. Effects of temperature and short term storage on density, rheological parameters and thermal parameters were investigated. First measurement was done at the beginning of storage and then the same sample was measured again after one week of storing. Density was measured by densimeter Mettler Toledo DM 40 at different temperatures. For dynamic viscosity measurement was used rotational viscometer Anton Paar DV-3P. The kinematic viscosity and fluidity were determined according to the definitions. Thermal parameters were measured by instrument Isomet 2104. Temperature dependencies of wine dynamic and kinematic viscosity had decreasing exponential shape and temperature dependencies of fluidity had an increasing exponential shape. Temperature dependencies of red wine thermal conductivity and diffusivity had increasing linear character. Decreasing polynomial functions were obtained for temperature dependencies of red wine density. The values of dynamic and kinematic viscosity, thermal conductivity and diffusivity, and density of red wine were a little bit higher after short term storing, which can be expressed by changed amount of water caused by evaporation. Due to the same reasons were values of fluidity little bit lower after storage.

The Density of Mid-sized Kuiper Belt Objects from ALMA Thermal Observations

Energy Technology Data Exchange (ETDEWEB)

Brown, Michael E. [California Institute of Technology, 1200 E California Blvd., Pasadena CA 91125 (United States); Butler, Bryan J. [National Radio Astronomy Observatory, 1003 Lopezville Rd., Socorro NM 87801 (United States)

2017-07-01

The densities of mid-sized Kuiper Belt objects (KBOs) are a key constraint in understanding the assembly of objects in the outer solar system. These objects are critical for understanding the currently unexplained transition from the smallest KBOs with densities lower than that of water, to the largest objects with significant rock content. Mapping this transition is made difficult by the uncertainties in the diameters of these objects, which maps into an even larger uncertainty in volume and thus density. The substantial collecting area of the Atacama Large Millimeter Array allows significantly more precise measurements of thermal emission from outer solar system objects and could potentially greatly improve the density measurements. Here we use new thermal observations of four objects with satellites to explore the improvements possible with millimeter data. We find that effects due to effective emissivity at millimeter wavelengths make it difficult to use the millimeter data directly to find diameters and thus volumes for these bodies. In addition, we find that when including the effects of model uncertainty, the true uncertainties on the sizes of outer solar system objects measured with radiometry are likely larger than those previously published. Substantial improvement in object sizes will likely require precise occultation measurements.

Inference of viscosity jump at 670 km depth and lower mantle viscosity structure from GIA observations

Science.gov (United States)

Nakada, Masao; Okuno, Jun'ichi; Irie, Yoshiya

2018-03-01

A viscosity model with an exponential profile described by temperature (T) and pressure (P) distributions and constant activation energy (E_{{{um}}}^{{*}} for the upper mantle and E_{{{lm}}}^* for the lower mantle) and volume (V_{{{um}}}^{{*}} and V_{{{lm}}}^*) is employed in inferring the viscosity structure of the Earth's mantle from observations of glacial isostatic adjustment (GIA). We first construct standard viscosity models with an average upper-mantle viscosity ({\\bar{η }_{{{um}}}}) of 2 × 1020 Pa s, a typical value for the oceanic upper-mantle viscosity, satisfying the observationally derived three GIA-related observables, GIA-induced rate of change of the degree-two zonal harmonic of the geopotential, {\\dot{J}_2}, and differential relative sea level (RSL) changes for the Last Glacial Maximum sea levels at Barbados and Bonaparte Gulf in Australia and for RSL changes at 6 kyr BP for Karumba and Halifax Bay in Australia. Standard viscosity models inferred from three GIA-related observables are characterized by a viscosity of ˜1023 Pa s in the deep mantle for an assumed viscosity at 670 km depth, ηlm(670), of (1 - 50) × 1021 Pa s. Postglacial RSL changes at Southport, Bermuda and Everglades in the intermediate region of the North American ice sheet, largely dependent on its gross melting history, have a crucial potential for inference of a viscosity jump at 670 km depth. The analyses of these RSL changes based on the viscosity models with {\\bar{η }_{{{um}}}} ≥ 2 × 1020 Pa s and lower-mantle viscosity structures for the standard models yield permissible {\\bar{η }_{{{um}}}} and ηlm (670) values, although there is a trade-off between the viscosity and ice history models. Our preferred {\\bar{η }_{{{um}}}} and ηlm (670) values are ˜(7 - 9) × 1020 and ˜1022 Pa s, respectively, and the {\\bar{η }_{{{um}}}} is higher than that for the typical value of oceanic upper mantle, which may reflect a moderate laterally heterogeneous upper

Relativistic self-focusing of intense laser beam in thermal collisionless quantum plasma with ramped density profile

Directory of Open Access Journals (Sweden)

S. Zare

2015-04-01

Full Text Available Propagation of a Gaussian x-ray laser beam has been analyzed in collisionless thermal quantum plasma with considering a ramped density profile. In this density profile due to the increase in the plasma density, an earlier and stronger self-focusing effect is noticed where the beam width oscillates with higher frequency and less amplitude. Moreover, the effect of the density profile slope and the initial plasma density on the laser propagation has been studied. It is found that, by increasing the initial density and the ramp slope, the laser beam focuses faster with less oscillation amplitude, smaller laser spot size and more oscillations. Furthermore, a comparison is made among the laser self-focusing in thermal quantum plasma, cold quantum plasma and classical plasma. It is realized that the laser self-focusing in the quantum plasma becomes stronger in comparison with the classical regime.

Viscosity measurements on metal melts at high pressure and viscosity calculations for the earth's core

International Nuclear Information System (INIS)

Mineev, Vladimir N; Funtikov, Aleksandr I

2004-01-01

A review is given of experimental and calculated data on the viscosity of iron-based melts on the melting curve. The interest in these data originates in the division of opinion on whether viscosity increases rather moderately or considerably in the high-pressure range. This disagreement is especially pronounced in the interpretation of the values of molten iron and its compounds in the environment of the earth's outer core. The conclusion on a substantial rise in viscosity mostly follows from the universal law, proposed by Brazhkin and Lyapin [1], of viscosity changing along the metal melting curve in the high-pressure range. The review analyzes available experimental and computational data, including the most recent ones. Data on viscosity of metals under shock wave compression in the megabar pressure range are also discussed. It is shown that data on viscosity of metal melts point to a small increase of viscosity on the melting curve. Specifics are discussed of the phase diagram of iron made more complex by the presence of several phase transitions and by the uncertainty in the position of the melting curve in the high-pressure range. Inaccuracies that arise in extrapolating the results of viscosity measurements to the pressure range corresponding to the earth's core environment are pointed out. (reviews of topical problems)

Development of the fabrication of ultra-low density ploy (4-methyl-1-pentene) (PMP) foams by thermal induced phase-inversion technique

International Nuclear Information System (INIS)

Zhang Lin; Wang Chaoyang; Luo Xuan; Du Kai; Tu Haiyan; Fan Hong; Luo Qing; Yuan Guanghui; Huang Lizhen

2003-01-01

By thermally induced phase-inversion technique, ploy (4-methyl-1-pentene) (PMP) foams are successfully prepared; the density and pore size are 3-80 mg/cm 3 and 1-20 μm respectively. Durene/naphthalene (60/40) is confirmed as the suitable solvent/nonsolvent binary system. The PMP's thermal properties are characterized by TG-DSC system. It is found that the foams thermal properties depend on the density. The thermal analysis method is utilized to measure the gelation of PMP in the binary solvent/nonsolvent system. The range of gelation temperature is preliminarily determined. The influence of mixture system composition and the cooling rate during the making of foams is discussed. TG-DSC is applied to determine the thermal properties of low-density PMP foams prepared in the laboratory. And the effect of density change on the thermal stability of foams are studied. The thermal analysis data play a great role in improving the foam quality. (authors)

Equation of state and viscosities from a gravity dual of the gluon plasma

Directory of Open Access Journals (Sweden)

R. Yaresko

2015-07-01

Full Text Available Employing new precision data of the equation of state of the SU(3 Yang–Mills theory (gluon plasma the dilaton potential of a gravity-dual model is adjusted in the temperature range (1–10Tc within a bottom-up approach. The ratio of bulk viscosity to shear viscosity follows then as ζ/η≈πΔvs2 for Δvs2<0.2 and achieves a maximum value of 0.94 at Δvs2≈0.3, where Δvs2≡1/3−vs2 is the non-conformality measure and vs2 is the velocity of sound squared, while the ratio of shear viscosity to entropy density is known as (4π−1 for the considered set-up with Hilbert action on the gravity side.

Partial molar volumes and viscosities of aqueous hippuric acid solutions containing LiCl and MnCl2 · 4H2O at 303.15 K

Science.gov (United States)

Deosarkar, S. D.; Tawde, P. D.; Zinjade, A. B.; Shaikh, A. I.

2015-09-01

Density (ρ) and viscosity (η) of aqueous hippuric acid (HA) solutions containing LiCl and MnCl2 · 4H2O have been studied at 303.15 K in order to understand volumetric and viscometric behavior of these systems. Apparent molar volume (φv) of salts were calculated from density data and fitted to Massons relation and partial molar volumes (φ{v/0}) at infinite dilution were determined. Relative viscosity data has been used to determine viscosity A and B coefficients using Jones-Dole relation. Partial molar volume and viscosity coefficients have been discussed in terms of ion-solvent interactions and overall structural fittings in solution.

Bound on viscosity and the generalized second law of thermodynamics

International Nuclear Information System (INIS)

Fouxon, Itzhak; Betschart, Gerold; Bekenstein, Jacob D.

2008-01-01

We describe a new paradox for ideal fluids. It arises in the accretion of an ideal fluid onto a black hole, where, under suitable boundary conditions, the flow can violate the generalized second law of thermodynamics. The paradox indicates that there is in fact a lower bound to the correlation length of any real fluid, the value of which is determined by the thermodynamic properties of that fluid. We observe that the universal bound on entropy, itself suggested by the generalized second law, puts a lower bound on the correlation length of any fluid in terms of its specific entropy. With the help of a new, efficient estimate for the viscosity of liquids, we argue that this also means that viscosity is bounded from below in a way reminiscent of the conjectured Kovtun-Son-Starinets lower bound on the ratio of viscosity to entropy density. We conclude that much light may be shed on the Kovtun-Son-Starinets bound by suitable arguments based on the generalized second law

Technological characteristics of meat - viscosity

OpenAIRE

DIBĎÁK, Tomáš

2012-01-01

This bachelor thesis is focused on the technological characteristics of meat, mainly viscosity of meat. At the beginning I dealt with construction of meat and various types of meat: beef, veal, pork, mutton, rabbit, poultry and venison. Then I described basic chemical composition of meat and it?s characteristic. In detail I dealt with viscosity of meat. Viscosity is the ability of meat to bind water both own and added. I mentioned influences, which effects viscosity and I presented the possib...

Shear and bulk viscosity of high-temperature gluon plasma

Science.gov (United States)

Zhang, Le; Hou, De-Fu

2018-05-01

We calculate the shear viscosity (η) and bulk viscosity (ζ) to entropy density (s) ratios η/s and ζ/s of a gluon plasma system in kinetic theory, including both the elastic {gg}≤ftrightarrow {gg} forward scattering and the inelastic soft gluon bremsstrahlung {gg}≤ftrightarrow {ggg} processes. Due to the suppressed contribution to η and ζ in the {gg}≤ftrightarrow {gg} forward scattering and the effective g≤ftrightarrow {gg} gluon splitting, Arnold, Moore and Yaffe (AMY) and Arnold, Dogan and Moore (ADM) have got the leading order computations for η and ζ in high-temperature QCD matter. In this paper, we calculate the correction to η and ζ in the soft gluon bremsstrahlung {gg}≤ftrightarrow {ggg} process with an analytic method. We find that the contribution of the collision term from the {gg}≤ftrightarrow {ggg} soft gluon bremsstrahlung process is just a small perturbation to the {gg}≤ftrightarrow {gg} scattering process and that the correction is at ∼5% level. Then, we obtain the bulk viscosity of the gluon plasma for the number-changing process. Furthermore, our leading-order result for bulk viscosity is the formula \\zeta \\propto \\tfrac{{α }s2{T}3}{ln}{α }s-1} in high-temperature gluon plasma. Supported by Ministry of Science and Technology of China (MSTC) under the “973” Project (2015CB856904(4)) and National Natural Science Foundation of China (11735007, 11521064)

Thermal properties of mixtures of mineral oil and natural ester in terms of their application in the transformer

Directory of Open Access Journals (Sweden)

Nadolny Zbigniew

2017-01-01

Full Text Available The article describes research results of thermal properties of mineral oil and natural ester. Percentage proportions of both the liquids were as follows: 100/0, 95/5, 80/20, 50/50, 20/80, 0/100. The authors present measurement results of thermal conductivity, viscosity, specific heat, density, and thermal expansion of the created mixtures. The measurements were taken in a relatively wide temperature range: 25 °C, 40 °C, 60 °C, and 80 °C. On the basis of the measurement results, convection heat transfer coefficient α was calculated and the most advantageous proportion of both the components of the mixture was pointed in terms of cooling effectiveness of the transformer.

Effects of nano-void density, size and spatial population on thermal conductivity: a case study of GaN crystal

International Nuclear Information System (INIS)

Zhou, X W; Jones, R E

2012-01-01

The thermal conductivity of a crystal is sensitive to the presence of surfaces and nanoscale defects. While this opens tremendous opportunities to tailor thermal conductivity, true ‘phonon engineering’ of nanocrystals for a specific electronic or thermoelectric application can only be achieved when the dependence of thermal conductivity on the defect density, size and spatial population is understood and quantified. Unfortunately, experimental studies of the effects of nanoscale defects are quite challenging. While molecular dynamics simulations are effective in calculating thermal conductivity, the defect density range that can be explored with feasible computing resources is unrealistically high. As a result, previous work has not generated a fully detailed understanding of the dependence of thermal conductivity on nanoscale defects. Using GaN as an example, we have combined a physically motivated analytical model and highly converged large-scale molecular dynamics simulations to study the effects of defects on thermal conductivity. An analytical expression for thermal conductivity as a function of void density, size, and population has been derived and corroborated with the model, simulations, and experiments. (paper)

Capillary waves with surface viscosity

Science.gov (United States)

Shen, Li; Denner, Fabian; Morgan, Neal; van Wachem, Berend; Dini, Daniele

2017-11-01

Experiments over the last 50 years have suggested a correlation between the surface (shear) viscosity and the stability of a foam or emulsion. With recent techniques allowing more accurate measurements of the elusive surface viscosity, we examine this link theoretically using small-amplitude capillary waves in the presence of the Marangoni effect and surface viscosity modelled via the Boussinesq-Scriven model. The surface viscosity effect is found to contribute a damping effect on the amplitude of the capillary wave with subtle differences to the effect of the convective-diffusive Marangoni transport. The general wave dispersion is augmented to take into account the Marangoni and surface viscosity effects, and a first-order correction to the critical damping wavelength is derived. The authors acknowledge the financial support of the Shell University Technology Centre for fuels and lubricants.

Viscosity of rock-ice mixtures and applications to the evolution of icy satellites

Science.gov (United States)

Friedson, A. J.; Stevenson, D. J.

1983-01-01

Theory and experiments are used to establish lower and upper bounds on the ratio of actual viscosity to pure ice viscosity for a suspension of rock particles in a water ice matrix. A rheological model for rock-ice mixtures is described, establishing bounds for the range of possible viscosity enhancements provided by a suspension of silicate spheres in an ice matrix. A parametrized thermal convection model is described and used to determine a criterion for criticality, defined as the heat flow and/or silicate volume fraction for which the satellite temperature profile intercepts the melting curve of water ice. The consequences of achieving this critical state are examined, and it is shown that under certain circumstances a 'runaway' differentiation can occur in which the silicates settle to form a core and extensive melting of water ice takes place, the latent heat being supplied by the gravitational energy of differentiation. A possible application of these results to Ganymede and Callisto is described.

Shear viscosity and out of equilibrium dynamics

CERN Document Server

El, Andrej; Xu, Zhe; Greiner, Carsten

2009-01-01

Using Grad’s method, we calculate the entropy production and derive a formula for the second-order shear viscosity coefficient in a one-dimensionally expanding particle system, which can also be considered out of chemical equilibrium. For a one-dimensional expansion of gluon matter with Bjorken boost invariance, the shear tensor and the shear viscosity to entropy density ratio η/s are numerically calculated by an iterative and self-consistent prescription within the second-order Israel-Stewart hydrodynamics and by a microscopic parton cascade transport theory. Compared with η/s obtained using the Navier-Stokes approximation, the present result is about 20% larger at a QCD coupling αs ∼ 0.3 (with η/s ≈ 0.18) and is a factor of 2–3 larger at a small coupling αs ∼ 0.01. We demonstrate an agreement between the viscous hydrodynamic calculations and the microscopic transport results on η/s, except when employing a small αs . On the other hand, we demonstrate that for such small αs , the gluon syst...

Microrheometric upconversion-based techniques for intracellular viscosity measurements

Science.gov (United States)

Rodríguez-Sevilla, Paloma; Zhang, Yuhai; de Sousa, Nuno; Marqués, Manuel I.; Sanz-Rodríguez, Francisco; Jaque, Daniel; Liu, Xiaogang; Haro-González, Patricia

2017-08-01

Rheological parameters (viscosity, creep compliance and elasticity) play an important role in cell function and viability. For this reason different strategies have been developed for their study. In this work, two new microrheometric techniques are presented. Both methods take advantage of the analysis of the polarized emission of an upconverting particle to determine its orientation inside the optical trap. Upconverting particles are optical materials that are able to convert infrared radiation into visible light. Their usefulness has been further boosted by the recent demonstration of their three-dimensional control and tracking by single beam infrared optical traps. In this work it is demonstrated that optical torques are responsible of the stable orientation of the upconverting particle inside the trap. Moreover, numerical calculations and experimental data allowed to use the rotation dynamics of the optically trapped upconverting particle for environmental sensing. In particular, the cytoplasm viscosity could be measured by using the rotation time and thermal fluctuations of an intracellular optically trapped upconverting particle, by means of the two previously mentioned microrheometric techniques.

Magnetically-charged black branes and viscosity/entropy ratios

Energy Technology Data Exchange (ETDEWEB)

Liu, Hai-Shan [Institute for Advanced Physics & Mathematics,Zhejiang University of Technology, Hangzhou 310023 (China); George P. & Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy,Texas A& M University, College Station, TX 77843 (United States); Lü, H. [Department of Physics, Beijing Normal University,Beijing 100875 (China); Pope, C.N. [George P. & Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy,Texas A& M University, College Station, TX 77843 (United States); DAMTP, Centre for Mathematical Sciences,Cambridge University, Wilberforce Road, Cambridge CB3 OWA (United Kingdom)

2016-12-19

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

Density,Viscosity,Refractive Index,and Speed of Sound in Binary Mixtures of Pyridine and 1-Alkanols(C6,C7,C8,C10)at 303.15 K

Institute of Scientific and Technical Information of China (English)

ALI Anwar; TARIQ Mohd; NABI Firdosa; SHAHJAHAN

2008-01-01

The densities(ρ),viscosities(η),refractive indices(nD),and speeds of sound(u),of binary mixtures of pyridine with 1-hexanoi,1-heptanol,1-octanol and 1-decanol,including those of pure liquids,were measured over the entire composition range at 303.15 K and atmospheric pressure.From these experimental data,the values of excess molar volumes(VE),deviations in isentropic compressibilities(△ks),viscosities(△η),molar refractions(△Rm),apparent and partial molar volumes(Vφ,2 and V0φ,2 ),apparent and partial molar compressibilities(Kφ,2 and K0φ,2 ),of alkanols in pyridine and their corresponding deviations(△V and △K)were calculated.The variations of these parameters with composition of the mixtures suggest that the strength of interactions in these mixtures follow the order:1-hexanol 1-heptanol 1-octanol 1-decanol.All the excess and deviation functions were fitted to Redlich-Kister polynomial equation to determine the fitting coefficients and the standard deviations.

Influence of reagents mixture density on the radiation-thermal synthesis of lithium-zinc ferrites

Science.gov (United States)

Surzhikov, A. P.; Lysenko, E. N.; Vlasov, V. A.; Malyshev, A. V.; Korobeynikov, M. V.; Mikhailenko, M. A.

2017-01-01

Influence of Li2CO3-ZnO-Fe2O3 powder reagents mixture density on the synthesis efficiency of lithium-zinc ferrites in the conditions of thermal heating or pulsed electron beam heating was studied by X-Ray diffraction and magnetization analysis. The results showed that the including a compaction of powder reagents mixture in ferrite synthesis leads to an increase in concentration of the spinel phase and decrease in initial components content in lithium-substituted ferrites synthesized by thermal or radiation-thermal heating.

The radiation and variable viscosity effects on electrically conducting fluid over a vertically moving plate subjected to suction and heat flux

Energy Technology Data Exchange (ETDEWEB)

Malekzadeh, P., E-mail: malekzadeh@pgu.ac.i [Department of Mechanical Engineering, Persian Gulf University, Bushehr 75168 (Iran, Islamic Republic of); Center of Excellence for Computational Mechanics, Shiraz University, Shiraz (Iran, Islamic Republic of); Moghimi, M.A. [Department of Mechanical Engineering, School of Engineering, Shaid Bahonar University, Kerman (Iran, Islamic Republic of); Nickaeen, M. [K.N. Toosi University of Technology, Tehran (Iran, Islamic Republic of)

2011-05-15

Research highlights: {yields} A new application of the differential quadrature method in thermo-fluid fields. {yields} Moving vertical plate with suction and heat flux is considered. {yields} Fluid with variable viscosity subjected to thermal radiation is studied. -- Abstract: In this paper, firstly, the applicability of the differential quadrature method (DQM) as an efficient and accurate numerical method for solving the problem of variable viscosity and thermally radiative unsteady magneto-hydrodynamic (MHD) flow over a moving vertical plate with suction and heat flux is investigated. The spatial as well as the temporal domains are discretized using the DQM. The fast rate of convergence of the method is demonstrated and for the cases that a solution is available, comparison is done. Then, effects of the temperature dependence of viscosity and different fluid parameters on the velocity and temperature of transient MHD flow subjected to the above mentioned boundary condition are studied.

MHD [magnetohydrodynamic] modes driven by anomalous electron viscosity and their role in fast sawtooth crashes

International Nuclear Information System (INIS)

Aydemir, A.Y.

1990-01-01

We derive the dispersion relations for both small and large-Δ' modes (m ≥ 2, and m = 1 modes, respectively) driven by anomalous electron viscosity. Under the assumption that the anomalous kinematic electron viscosity is comparable to the anomalous electron thermal diffusivity, we find that the viscous mode typically has a higher growth rate than the corresponding resistive mode. We compare computational results in cylindrical and toroidal geometries with theory and present some nonlinear results for viscous m = 1 modes in both circular and D-shaped boundaries and discuss their possible rile in fast sawtooth crashes. 30 ref., 5 figs., 1 tab

POWER SPECTRAL DENSITY OF FLUCTUATIONS OF BULK AND THERMAL SPEEDS IN THE SOLAR WIND

International Nuclear Information System (INIS)

Šafránková, J.; Němeček, Z.; Němec, F.; Přech, L.; Chen, C. H. K.; Zastenker, G. N.

2016-01-01

This paper analyzes solar wind power spectra of bulk and thermal speed fluctuations that are computed with a time resolution of 32 ms in the frequency range of 0.001–2 Hz. The analysis uses measurements of the Bright Monitor of the Solar Wind on board the Spektr-R spacecraft that are limited to 570 km s 1 bulk speed. The statistics, based on more than 42,000 individual spectra, show that: (1) the spectra of bulk and thermal speeds can be fitted by two power-law segments; (2) despite their large variations, the parameters characterizing frequency spectrum fits computed on each particular time interval are very similar for both quantities; (3) the median slopes of the bulk and thermal speeds of the segment attributed to the MHD scale are 1.43 and 1.38, respectively, whereas they are 3.08 and 2.43 in the kinetic range; (4) the kinetic range slopes of bulk and thermal speed spectra become equal when either the ion density or magnetic field strength are high; (5) the break between MHD and kinetic scales seems to be controlled by the ion β parameter; (6) the best scaling parameter for bulk and thermal speed variations is a sum of the inertial length and proton thermal gyroradius; and (7) the above conclusions can be applied to the density variations if the background magnetic field is very low.

POWER SPECTRAL DENSITY OF FLUCTUATIONS OF BULK AND THERMAL SPEEDS IN THE SOLAR WIND

Energy Technology Data Exchange (ETDEWEB)

Šafránková, J.; Němeček, Z.; Němec, F.; Přech, L. [Charles University, Faculty of Mathematics and Physics, V Holešovičkách 2, 180 00 Prague 8 (Czech Republic); Chen, C. H. K. [Department of Physics, Imperial College London, London SW7 2AZ (United Kingdom); Zastenker, G. N., E-mail: jana.safrankova@mff.cuni.cz [Space Research Institute of Russian Academy of Sciences, Moscow, Russia, Profsoyuznaya ul. 84/32, Moscow 117997 (Russian Federation)

2016-07-10

This paper analyzes solar wind power spectra of bulk and thermal speed fluctuations that are computed with a time resolution of 32 ms in the frequency range of 0.001–2 Hz. The analysis uses measurements of the Bright Monitor of the Solar Wind on board the Spektr-R spacecraft that are limited to 570 km s{sup 1} bulk speed. The statistics, based on more than 42,000 individual spectra, show that: (1) the spectra of bulk and thermal speeds can be fitted by two power-law segments; (2) despite their large variations, the parameters characterizing frequency spectrum fits computed on each particular time interval are very similar for both quantities; (3) the median slopes of the bulk and thermal speeds of the segment attributed to the MHD scale are 1.43 and 1.38, respectively, whereas they are 3.08 and 2.43 in the kinetic range; (4) the kinetic range slopes of bulk and thermal speed spectra become equal when either the ion density or magnetic field strength are high; (5) the break between MHD and kinetic scales seems to be controlled by the ion β parameter; (6) the best scaling parameter for bulk and thermal speed variations is a sum of the inertial length and proton thermal gyroradius; and (7) the above conclusions can be applied to the density variations if the background magnetic field is very low.

Estimation of the shear viscosity from 3FD simulations of Au + Au collisions at √(sNN) = 3.3-39 GeV

International Nuclear Information System (INIS)

Ivanov, Yu.B.; Soldatov, A.A.

2016-01-01

An effective shear viscosity in central Au+Au collisions is estimated in the range of incident energies 3.3 GeV≤√(s NN )≤39 GeV. The simulations are performed within a three-fluid model employing three different equations of state with and without the deconfinement transition. In order to estimate this effective viscosity, we consider the entropy produced in the 3FD simulations as if it is generated within the conventional one-fluid viscous hydrodynamics. It is found that the effective viscosity within the different considered scenarios is very similar at the expansion stage of the collision: as a function of temperature (T) the viscosity-to-entropy ratio behaves as η/s∝1/T 4 ; as a function of the net-baryon density (n B ), η/s∝1/s, i.e. it is mainly determined by the density dependence of the entropy density. The above dependences take place along the dynamical trajectories of Au+Au collisions. At the final stages of the expansion the η/s values are ranged from ∝0.05 at the highest considered energies to ∝.5 at the lowest ones. (orig.)

Effect of ionic and non-ionic contrast media on whole blood viscosity, plasma viscosity and hematocrit in vitro

International Nuclear Information System (INIS)

Aspelin, P.

1978-01-01

The effect of the ionic contrast media diatrizoate, iocarmate and metrizoate and the non-ionic metrizamide on whole blood viscosity, plasma viscosity and hematocrit was investigated. All the contrast media increased whole blood and plasma viscosity and reduced the hematocrit. The whole blood viscosity increased with increasing osmolality of the contrast medium solutions, whereas the plasma viscosity increased with increasing viscosity of the contrast medium solutions. The higher the osmolality of the contrast media, the lower the hematocrit became. The normal shear-thinning (decreasing viscosity with increasing shear rate) property of blood was reduced when contrast medium was added to the blood. At 50 per cent volume ratio (contrast medium to blood), the ionic contrast media converted the blood into a shear-thickening (increasing viscosity with increasing shear rate) suspension, indicating a marked rigidification of the single red cell, while the non-ionic contrast medium still produced shear-thinning, indicating less rigidification of the red cell (p<0.01). (Auth.)

The viscosity of dimethyl ether

DEFF Research Database (Denmark)

Sivebæk, Ion Marius; Jakobsen, Jørgen

2007-01-01

and NOx traps are installed. The most significant problem encountered when engines are fuelled with DME is that the injection equipment breaks down prematurely due to extensive wear. This tribology issue can be explained by the very low lubricity and viscosity of DME. Recently, laboratory methods have...... appeared capable of measuring these properties of DME. The development of this is rendered difficult because DME has to be pressurised to remain in the liquid state and it dissolves most of the commercially available elastomers. This paper deals fundamentally with the measurement of the viscosity of DME...... and extends the discussion to the difficulty of viscosity establishing of very thin fluids. The main issue here is that it is not easy to calibrate the viscometers in the very low viscosity range corresponding to about one-fifth of that of water. The result is that the low viscosity is measured at high...

Synthesis of high-temperature viscosity stabilizer used in drilling fluid

Science.gov (United States)

Zhang, Yanna; Luo, Huaidong; Shi, Libao; Huang, Hongjun

2018-02-01

Abstract For a well performance drilling fluid, when it operates in deep wells under high temperature, the most important property required is the thermal stability. The drilling fluid properties under high temperature can be controlled by proper selection of viscosity stabilizer, which can capture oxygen to protect polymer agent in the drilling fluid. In this paper a viscosity stabilizer PB-854 is described, which was synthesized by 4-phenoxybutyl bromide, paraformaldehyde, and phloroglucinol using etherification method and condensation reaction. We studied the effect of catalyst dosage, temperature, time, and stirring rate on the synthetic yield. Under this condition: molar ratio of 2-tert-Butylphenol, paraformaldehyde and phloroglucinol of 2:1:2.5, reacting temperature of 100 °C, stirring rate of 100 r min-1, and mass content of catalyst of 15 %, char yield of 5-bromine-3-tert-butyl salicylaldehyde reached 86 %. Under this condition: molar ratio of 5-bromine-3-tert-butyl salicylaldehyde and phloroglucinol of 4, reacting temperature of 60 °C, reacting time of 30 min, volume content of sulphuric acid of 80 %, char yield of the target product viscosity stabilizer PB-854 is 86%. Finally, in this paper, infrared spectroscopy is adopted to analyse the structure of the synthetic product PB-854.The improvement in the stability of drilling fluid was further shown after adding the viscosity stabilizer in the common polymer drilling fluid under high temperature conditions of 120 °C ˜ 180 °C. The results show significant change in terms of fluid stability in the presence of this new stabilizer as it provides better stability.

Review of thermal expansion and density of uranium and plutonium carbides

International Nuclear Information System (INIS)

Andrew, J.F.; Latimer, T.W.

1975-07-01

The published literature on linear thermal expansion and density of uranium and plutonium carbide nuclear fuels, including UC, PuC, (U,Pu)C, U 2 C 3 , Pu 2 C 3 , and (U,Pu) 2 C 3 , is critically reviewed. Recommended values are given in tabular form and additional experimental studies needed for completeness are outlined. 16 tables, 52 references

Effect of renal replacement therapy on viscosity in end-stage renal disease patients.

Science.gov (United States)

Feriani, M; Kimmel, P L; Kurantsin-Mills, J; Bosch, J P

1992-02-01

Viscosity, an important determinant of microcirculatory hemodynamics, is related to hematocrit (HCT), and may be altered by renal failure or its treatment. To assess these factors, we studied the effect of dialysis on the viscosity of whole blood, plasma, and reconstituted 70% HCT blood of eight continuous ambulatory peritoneal dialysis (CAPD) and nine hemodialysis (HD) patients under steady shear flow conditions at different shear rates, before and after dialysis, compared with nine normal subjects. The density of the red blood cells (RBCs), a marker of cell hydration, was measured in HD patients by a nonaqueous differential floatation technique. Whole blood viscosity was higher in controls than patients, and correlated with HCT before treatment (P less than 0.05) at shear rates of 11.5 to 230 s-1) in HD patients, and 23 to 230 s-1 in all end-stage renal disease (ESRD) patients. In contrast, whole blood viscosity correlated with HCT in CAPD patients only at the lowest shear rates (2.3 and 5.75 s-1, P less than 0.05). Plasma viscosity was higher in CAPD patients than both HD patients before treatment and controls (P less than 0.05, analysis of variance [ANOVA]), despite lower plasma total protein, albumin, and similar fibrinogen concentration compared with HD patients. When all samples were reconstituted to 70% HCT, CAPD patients had higher whole blood viscosity than control subjects'. The high HCT blood viscosity of the ESRD patients was higher than control subjects' at capillary shear rates, suggesting increased RBC aggregation and decreased RBC deformability in patients with renal disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Cancer therapy using non-thermal atmospheric pressure plasma with ultra-high electron density

International Nuclear Information System (INIS)

Tanaka, Hiromasa; Mizuno, Masaaki; Toyokuni, Shinya; Maruyama, Shoichi; Kodera, Yasuhiro; Terasaki, Hiroko; Adachi, Tetsuo; Kato, Masashi; Kikkawa, Fumitaka; Hori, Masaru

2015-01-01

Cancer therapy using non-thermal atmospheric pressure plasma is a big challenge in plasma medicine. Reactive species generated from plasma are key factors for treating cancer cells, and thus, non-thermal atmospheric pressure plasma with high electron density has been developed and applied for cancer treatment. Various cancer cell lines have been treated with plasma, and non-thermal atmospheric plasma clearly has anti-tumor effects. Recent innovative studies suggest that plasma can both directly and indirectly affect cells and tissues, and this observation has widened the range of applications. Thus, cancer therapy using non-thermal atmospheric pressure plasma is promising. Animal experiments and understanding the mode of action are essential for clinical application in the future. A new academic field that combines plasma science, the biology of free radicals, and systems biology will be established

Cancer therapy using non-thermal atmospheric pressure plasma with ultra-high electron density

Energy Technology Data Exchange (ETDEWEB)

Tanaka, Hiromasa [Institute of Innovation for Future Society, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Center for Advanced Medicine and Clinical Research, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Mizuno, Masaaki [Center for Advanced Medicine and Clinical Research, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Toyokuni, Shinya [Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Maruyama, Shoichi [Department of Nephrology, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Kodera, Yasuhiro [Department of Gastroenterological Surgery (Surgery II), Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Terasaki, Hiroko [Department of Ophthalmology, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Adachi, Tetsuo [Laboratory of Clinical Pharmaceutics, Gifu Pharmaceutical University, 501-1196 Gifu (Japan); Kato, Masashi [Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Kikkawa, Fumitaka [Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Hori, Masaru [Institute of Innovation for Future Society, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

2015-12-15

Cancer therapy using non-thermal atmospheric pressure plasma is a big challenge in plasma medicine. Reactive species generated from plasma are key factors for treating cancer cells, and thus, non-thermal atmospheric pressure plasma with high electron density has been developed and applied for cancer treatment. Various cancer cell lines have been treated with plasma, and non-thermal atmospheric plasma clearly has anti-tumor effects. Recent innovative studies suggest that plasma can both directly and indirectly affect cells and tissues, and this observation has widened the range of applications. Thus, cancer therapy using non-thermal atmospheric pressure plasma is promising. Animal experiments and understanding the mode of action are essential for clinical application in the future. A new academic field that combines plasma science, the biology of free radicals, and systems biology will be established.

Excess molar volume and viscosity deviation for binary mixtures of γ-butyrolactone with dimethyl sulfoxide

International Nuclear Information System (INIS)

Krakowiak, Joanna; Śmiechowski, Maciej

2017-01-01

Highlights: • Densities and viscosities of DMSO-GBL binary liquid mixtures were measured. • The volumetric parameters and excess quantities were obtained. • Ab initio calculations were performed for single molecules and dimers in the studied mixture. • The interactions in solutions are weaker than in pure solvents. - Abstract: The densities of binary liquid mixtures of dimethyl sulfoxide and γ-butyrolactone at (293.15, 298.15, 303.15 and 313.15) K and viscosity at T = 298.15 K have been measured at atmospheric pressure over the entire range of concentration. From these data the excess molar volumes V E at (293.15, 298.15, 303.15 and 313.15) K and the viscosity deviation, the excess entropy, and the excess Gibbs energy of activation for viscous flow at T = 298.15 K have been determined. These data were mathematically represented by the Redlich-Kister polynomial. Partial and apparent molar volumes have been calculated for better understanding of the interactions in the binary systems. The obtained data indicate the lack of specific interactions between unlike molecules, which seem to be a little weaker as compared to the interactions in pure solvents.

Excess molar volume along with viscosity, refractive index and relative permittivity for binary mixtures of exo-tetrahydrodicyclopentadiene with four octane isomers

International Nuclear Information System (INIS)

Yue, Lei; Qin, Xiaomei; Wu, Xi; Xu, Li; Guo, Yongsheng; Fang, Wenjun

2015-01-01

Highlights: • Binary mixtures of JP-10 with octane isomers are studied as model hydrocarbon fuels. • Density, viscosity, refractive index and relative permittivity are determined. • Excess molar volumes and viscosity deviations are calculated and correlated. - Abstract: The fundamental physical properties including density, viscosity, refractive index and relative permittivity, have been measured for binary mixtures of exo-tetrahydrodicyclopentadiene (JP-10) with four octane isomers (n-octane, 3-methylheptane, 2,4-dimethylhexane and 2,2,4-trimethylpentane) over the whole composition range at temperatures T = (293.15 to 313.15) K and pressure p = 0.1 MPa. The values of excess molar volume (V m E ), viscosity deviation (Δη), refractive index deviation (Δn D ) and relative permittivity deviation (Δε r ) are then calculated. All of the values of V m E and Δη are observed to be negative, while those of Δn D and Δε r are close to zero. The effects of temperature and composition on the variation of V m E values are discussed. The negative values of V m E and Δη are conductive to high-density and low-resistance of fuels, which is favorable for the design and preparation of advanced hydrocarbon fuels

Volumetric, viscosity, and electrical conductivity properties of aqueous solutions of two n-butylammonium-based protic ionic liquids at several temperatures

International Nuclear Information System (INIS)

Xu, Yingjie

2013-01-01

Highlights: • Densities and viscosities of N4AC + water and N4NO 3 + water mixtures were measured. • Volumetric and viscosity properties were calculated. • Redlich–Kister equation was used to correlate the excess molar volumes and viscosity deviations. • Electrical conductivity was fitted according to the empirical Casteel–Amis equation. • The interactions and structural effects of N4AC or N4NO 3 with water were analyzed. -- Abstract: Densities and viscosities of (n-butylammonium acetate (N4AC) protic ionic liquid + water) and (n-butylammonium nitrate (N4NO 3 ) protic ionic liquid + water) mixtures were measured at T = (293.15, 298.15, 303.15, 308.15, and 313.15) K under atmospheric pressure. Electrical conductivities of the above-mentioned systems were determined at 298.15 K. Excess molar volumes and viscosity deviations were obtained from the experimental results and fitted to the Redlich–Kister equation with satisfactory results. Other volumetric properties, such as apparent molar volumes, partial molar volumes, and excess partial molar volumes were also calculated. The concentration dependence of electrical conductivity was fitted according to the empirical Casteel–Amis equation. Based on the measured and derived properties, the molecular interactions and structural factors in the above-mentioned systems were discussed

Effect of viscosity on learned satiation

NARCIS (Netherlands)

Mars, M.; Hogenkamp, P.S.; Gosses, A.M.; Stafleu, A.; Graaf, C.de

2009-01-01

A higher viscosity of a food leads to a longer orosensory stimulation. This may facilitate the learned association between sensory signals and metabolic consequences. In the current study we investigated the effect of viscosity on learned satiation. In two intervention groups a low viscosity (LV)

Variación de las propiedades físicas de la grasa de cacao con la temperatura

OpenAIRE

de Dios Alvarado, Juan

1994-01-01

Values of physical properties determined at different temperatures in fat extracted from fresh cacao seeds (Theobroma cacao) are presented. Linear relationships define the effect of temperature on the refraction index, density and surface tension, a logarithmic function was established for viscosity. The values of density and viscosity are used to determine the coefficient of volumetric thermal expansion and activation energy, respectively. Data of specific heat, thermal diffusivity and therm...

Thermal properties of silica-filled high density polyethylene composites compatibilized with glut palmitate

Science.gov (United States)

Samsudin, Dalina; Ismail, Hanafi; Othman, Nadras; Hamid, Zuratul Ain Abdul

2017-07-01

A study of thermal properties resulting from the utilization of Glut Palmitate (GP) on the silica filled high density polyethylene (HDPE) composites was carried out. The composites with the incorporation of GP at 0.5, 1.0, 2.0 and 3.0 phr were prepared by using an internal mixer at the temperature 180 °C and the rotor speed of 50 rpm. The thermal behaviours of the composites were then investigated using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It was found that the crystallinity and the thermal stability of the composites increased with the incorporation of GP. The highest crystallinity contents and decomposition temperatures were observed at the 1 phr GP loading.

A comparison of performance of several artificial intelligence methods for predicting the dynamic viscosity of TiO2/SAE 50 nano-lubricant

Science.gov (United States)

Hemmat Esfe, Mohammad; Tatar, Afshin; Ahangar, Mohammad Reza Hassani; Rostamian, Hossein

2018-02-01

Since the conventional thermal fluids such as water, oil, and ethylene glycol have poor thermal properties, the tiny solid particles are added to these fluids to increase their heat transfer improvement. As viscosity determines the rheological behavior of a fluid, studying the parameters affecting the viscosity is crucial. Since the experimental measurement of viscosity is expensive and time consuming, predicting this parameter is the apt method. In this work, three artificial intelligence methods containing Genetic Algorithm-Radial Basis Function Neural Networks (GA-RBF), Least Square Support Vector Machine (LS-SVM) and Gene Expression Programming (GEP) were applied to predict the viscosity of TiO2/SAE 50 nano-lubricant with Non-Newtonian power-law behavior using experimental data. The correlation factor (R2), Average Absolute Relative Deviation (AARD), Root Mean Square Error (RMSE), and Margin of Deviation were employed to investigate the accuracy of the proposed models. RMSE values of 0.58, 1.28, and 6.59 and R2 values of 0.99998, 0.99991, and 0.99777 reveal the accuracy of the proposed models for respective GA-RBF, CSA-LSSVM, and GEP methods. Among the developed models, the GA-RBF shows the best accuracy.

Effect of Interface Structure on Thermal Boundary Conductance by using First-principles Density Functional Perturbation Theory

Institute of Scientific and Technical Information of China (English)

GAO Xue; ZHANG Yue; SHANG Jia-Xiang

2011-01-01

We choose a Si/Ge interface as a research object to investigate the infiuence of interface disorder on thermal boundary conductance. In the calculations, the diffuse mismatch model is used to study thermal boundary conductance between two non-metallic materials, while the phonon dispersion relationship is calculated by the first-principles density functional perturbation theory. The results show that interface disorder limits thermal transport. The increase of atomic spacing at the interface results in weakly coupled interfaces and a decrease in the thermal boundary conductance. This approach shows a simplistic method to investigate the relationship between microstructure and thermal conductivity.%We choose a Si/Ge interface as a research object to investigate the influence of interface disorder on thermal boundary conductance.In the calculations,the diffuse mismatch model is used to study thermal boundary conductance between two non-metallic materials,while the phonon dispersion relationship is calculated by the first-principles density functional perturbation theory.The results show that interface disorder limits thermal transport.The increase of atomic spacing at the interface results in weakly coupled interfaces and a decrease in the thermal boundary conductance.This approach shows a simplistic method to investigate the relationship between microstructure and thermal conductivity.It is well known that interfaces can play a dominant role in the overall thermal transport characteristics of structures whose length scale is less than the phonon mean free path.When heat flows across an interface between two different materials,there exists a temperature jump at the interface.Thermal boundary conductance (TBC),which describes the efficiency of heat flow at material interfaces,plays an importance role in the transport of thermal energy in nanometerscale devices,semiconductor superlattices,thin film multilayers and nanocrystalline materials.[1

Comparison of parallel viscosity with neoclassical theory

International Nuclear Information System (INIS)

Ida, K.; Nakajima, N.

1996-04-01

Toroidal rotation profiles are measured with charge exchange spectroscopy for the plasma heated with tangential NBI in CHS heliotron/torsatron device to estimate parallel viscosity. The parallel viscosity derived from the toroidal rotation velocity shows good agreement with the neoclassical parallel viscosity plus the perpendicular viscosity. (μ perpendicular = 2 m 2 /s). (author)

Magmatic densities control erupted volumes in Icelandic volcanic systems

Science.gov (United States)

Hartley, Margaret; Maclennan, John

2018-04-01

Magmatic density and viscosity exert fundamental controls on the eruptibility of magmas. In this study, we investigate the extent to which magmatic physical properties control the eruptibility of magmas from Iceland's Northern Volcanic Zone (NVZ). By studying subaerial flows of known age and volume, we are able to directly relate erupted volumes to magmatic physical properties, a task that has been near-impossible when dealing with submarine samples dredged from mid-ocean ridges. We find a strong correlation between magmatic density and observed erupted volumes on the NVZ. Over 85% of the total volume of erupted material lies close to a density and viscosity minimum that corresponds to the composition of basalts at the arrival of plagioclase on the liquidus. These magmas are buoyant with respect to the Icelandic upper crust. However, a number of small-volume eruptions with densities greater than typical Icelandic upper crust are also found in Iceland's neovolcanic zones. We use a simple numerical model to demonstrate that the eruption of magmas with higher densities and viscosities is facilitated by the generation of overpressure in magma chambers in the lower crust and uppermost mantle. This conclusion is in agreement with petrological constraints on the depths of crystallisation under Iceland.

Magmatic Densities Control Erupted Volumes in Icelandic Volcanic Systems

Directory of Open Access Journals (Sweden)

Margaret Hartley

2018-04-01

Full Text Available Magmatic density and viscosity exert fundamental controls on the eruptibility of magmas. In this study, we investigate the extent to which magmatic physical properties control the eruptibility of magmas from Iceland's Northern Volcanic Zone (NVZ. By studying subaerial flows of known age and volume, we are able to directly relate erupted volumes to magmatic physical properties, a task that has been near-impossible when dealing with submarine samples dredged from mid-ocean ridges. We find a strong correlation between magmatic density and observed erupted volumes on the NVZ. Over 85% of the total volume of erupted material lies close to a density and viscosity minimum that corresponds to the composition of basalts at the arrival of plagioclase on the liquidus. These magmas are buoyant with respect to the Icelandic upper crust. However, a number of small-volume eruptions with densities greater than typical Icelandic upper crust are also found in Iceland's neovolcanic zones. We use a simple numerical model to demonstrate that the eruption of magmas with higher densities and viscosities is facilitated by the generation of overpressure in magma chambers in the lower crust and uppermost mantle. This conclusion is in agreement with petrological constraints on the depths of crystallization under Iceland.

Ionization of liquid argon by x-rays: effect of density on electron thermalization and free ion yields

International Nuclear Information System (INIS)

Huang, S.S.-S.; Gee, N.; Freeman, G.R.

1991-01-01

Free ion yields were measured in liquid argon as a function of electric field strength at densities 736-1343 kg/m 3 (temperatures 149-95 K). The field dependence of the yields was parametrized using the extended Onsager and box models. Over the present density range the total ion yield was constant within 1% and was taken as 4.4, the average of earlier values at 87-91 K. The absence of internal vibrational modes in argon makes its electron thermalizing ability smaller than that of methane. The electron thermalization distance b GP in liquid argon is 3-5 times longer than that in liquid methane at a given d/d c (d c = critical fluid density). (author)

Thermal turbulent convection: thermal plumes and fluctuations; Convection thermique turbulente: panaches et fluctuations

Energy Technology Data Exchange (ETDEWEB)

Gibert, M

2007-10-15

In this study we investigate the phenomenon of thermal turbulent convection in new and unprecedented ways. The first system we studied experimentally is an infinite vertical channel, where a constant vertical mean gradient of temperature exists. Inside this channel the average mass flux is null. The results obtained from our measurements reveal that the flow is mainly inertial; indeed the dissipative coefficients (here the viscosity) play a role only to define a coherence length L. This length is the distance over which the thermal plumes can be considered as 'free falling' objects. The horizontal transport, of heat and momentum, is entirely due to fluctuations. The associated 'mixing length' is small compared to the channel width. In the other hand, the vertical heat transport is due to coherent structures: the heat plumes. Those objects were also investigated in a Lagrangian study of the flow in the bulk of a Rayleigh-Benard cell. The probe, which has the same density as the fluid used in this experiment, is a sphere of 2 cm in diameter with embarked thermometers and radio-emitter. The heat plumes transport it, which allows a statistical study of such objects. (author)

Estimation of viscosity based on transverse momentum correlations

Science.gov (United States)

Sharma, Monika

2010-02-01

The heavy ion program at RHIC created a paradigm shift in the exploration of strongly interacting hot and dense matter. An important milestone achieved is the discovery of the formation of strongly interacting matter which seemingly flows like a perfect liquid at temperatures on the scale of T ˜ 2 x10^12 K [1]. As a next step, we consider measurements of transport coefficients such as kinematic, shear or bulk viscosity? Many calculations based on event anisotropy measurements indicate that the shear viscosity to the entropy density ratio (η/s) of the fluid formed at RHIC is significantly below that of all known fluids including the superfluid ^4He [2]. Precise determination of η/s ratio is currently a subject of extensive study. We present an alternative technique for the determination of medium viscosity proposed by Gavin and Aziz [3]. Preliminary results of measurements of the evolution of the transverse momentum correlation function with collision centrality of Au + Au interactions at √sNN = 200 GeV will be shown. We present results on differential version of the correlation measure and describe its use for the experimental determination of η/s.[4pt] [1] J. Adams et al., [STAR Collaboration], Nucl. Phys. A 757 (2005) 102.[0pt] [2] R. A. Lacey et al., Phys. Rev. Lett. 98 (2007) 092301.[0pt] [3] S. Gavin and M. Abdel-Aziz, Phys. Rev. Lett. 97 (2006) 162302. )

Electrical conductivity and shear viscosity of quark gluon plasma in a quasiparticle model

International Nuclear Information System (INIS)

Srivastava, P.K.; Mohanty, B.

2014-01-01

Relativistic heavy-ion collisions (HIC) have reported the formation of a strongly coupled quark gluon plasma (sQGP). To study the properties of this sQGP is the main focus nowadays. Among these the shear viscosity (η) and electrical conductivity (σ el ) could reflect the transport properties of the medium. By studying the shear viscosity or more specifically shear viscosity to entropy density ratio (η/s), one can understand the nature of interactions among the constituents of the produced medium, it gives a measure of the fluidity. Electrical conductivity represents the linear response of the system to an applied external electric field. The basic question one could ask is that whether the matter created at heavy ion collision experiment is an electrical conductor or an insulator. Recent lattice QCD as well as phenomenological studies have shown that these transport quantities show some kind of minimum in its variation with respect to temperature near the temperature corresponding to the transition from hadronic phase to quark-gluon phase

Ultrasonication effects on thermal and rheological properties of carbon nanotube suspensions.

Science.gov (United States)

Ruan, Binglu; Jacobi, Anthony M

2012-02-14

The preparation of nanofluids is very important to their thermophysical properties. Nanofluids with the same nanoparticles and base fluids can behave differently due to different nanofluid preparation methods. The agglomerate sizes in nanofluids can significantly impact the thermal conductivity and viscosity of nanofluids and lead to a different heat transfer performance. Ultrasonication is a common way to break up agglomerates and promote dispersion of nanoparticles into base fluids. However, research reports of sonication effects on nanofluid properties are limited in the open literature. In this work, sonication effects on thermal conductivity and viscosity of carbon nanotubes (0.5 wt%) in an ethylene glycol-based nanofluid are investigated. The corresponding effects on the agglomerate sizes and the carbon nanotube lengths are observed. It is found that with an increased sonication time/energy, the thermal conductivity of the nanofluids increases nonlinearly, with the maximum enhancement of 23% at sonication time of 1,355 min. However, the viscosity of nanofluids increases to the maximum at sonication time of 40 min, then decreases, finally approaching the viscosity of the pure base fluid at a sonication time of 1,355 min. It is also observed that the sonication process not only reduces the agglomerate sizes but also decreases the length of carbon nanotubes. Over the current experimental range, the reduction in agglomerate size is more significant than the reduction of the carbon nanotube length. Hence, the maximum thermal conductivity enhancement and minimum viscosity increase are obtained using a lengthy sonication, which may have implications on application.

An estimate of the bulk viscosity of the hadronic medium

Science.gov (United States)

Sarwar, Golam; Chatterjee, Sandeep; Alam, Jane

2017-05-01

The bulk viscosity (ζ) of the hadronic medium has been estimated within the ambit of the Hadron Resonance Gas (HRG) model including the Hagedorn density of states. The HRG thermodynamics within a grand canonical ensemble provides the mean hadron number as well as its fluctuation. The fluctuation in the chemical composition of the hadronic medium in the grand canonical ensemble can result in non-zero divergence of the hadronic fluid flow velocity, allowing us to estimate the ζ of the hadronic matter up to a relaxation time. We study the influence of the hadronic spectrum on ζ and find its correlation with the conformal symmetry breaking measure, ε -3P. We estimate ζ along the contours with constant, S/{N}B (total entropy/net baryon number) in the T-μ plane (temperature-baryonic chemical potential) for S/{N}B=30,45 and 300. We also assess the value of ζ on the chemical freeze-out curve for various centers of mass energy (\\sqrt{{s}{NN}}) and find that the bulk viscosity to entropy density ratio, \\zeta /s is larger in the energy range of the beam energy scan program of RHIC, low energy SPS run, AGS, NICA and FAIR, than LHC energies.

Parametric dependence of density limits in the Tokamak Experiment for Technology Oriented Research (TEXTOR): Comparison of thermal instability theory with experiment

International Nuclear Information System (INIS)

Kelly, F.A.; Stacey, W.M.; Rapp, J.

2001-01-01

The observed dependence of the TEXTOR [Tokamak Experiment for Technology Oriented Research: E. Hintz, P. Bogen, H. A. Claassen et al., Contributions to High Temperature Plasma Physics, edited by K. H. Spatschek and J. Uhlenbusch (Akademie Verlag, Berlin, 1994), p. 373] density limit on global parameters (I, B, P, etc.) and wall conditioning is compared with the predicted density limit parametric scaling of thermal instability theory. It is necessary first to relate the edge parameters of the thermal instability theory to n(bar sign) and the other global parameters. The observed parametric dependence of the density limit in TEXTOR is generally consistent with the predicted density limit scaling of thermal instability theory. The observed wall conditioning dependence of the density limit can be reconciled with the theory in terms of the radiative emissivity temperature dependence of different impurities in the plasma edge. The thermal instability theory also provides an explanation of why symmetric detachment precedes radiative collapse for most low power shots, while a multifaceted asymmetric radiation from the edge MARFE precedes detachment for most high power shots

The Effects of Earth's Outer Core's Viscosity on Geodynamo Models

Science.gov (United States)

Dong, C.; Jiao, L.; Zhang, H.

2017-12-01

Geodynamo process is controlled by mathematic equations and input parameters. To study effects of parameters on geodynamo system, MoSST model has been used to simulate geodynamo outputs under different outer core's viscosity ν. With spanning ν for nearly three orders when other parameters fixed, we studied the variation of each physical field and its typical length scale. We find that variation of ν affects the velocity field intensely. The magnetic field almost decreases monotonically with increasing of ν, while the variation is no larger than 30%. The temperature perturbation increases monotonically with ν, but by a very small magnitude (6%). The averaged velocity field (u) of the liquid core increases with ν as a simple fitted scaling relation: u∝ν0.49. The phenomenon that u increases with ν is essentially that increasing of ν breaks the Taylor-Proudman constraint and drops the critical Rayleigh number, and thus u increases under the same thermal driving force. Forces balance is analyzed and balance mode shifts with variation of ν. When compared with former studies of scaling laws, this study supports the conclusion that in a certain parameter range, the magnetic field strength doesn't vary much with the viscosity, but opposes to the assumption that the velocity field has nothing to do with the outer core viscosity.

Effects of ultrasound energy density on the non-thermal pasteurization of chocolate milk beverage.

Science.gov (United States)

Monteiro, Sara H M C; Silva, Eric Keven; Alvarenga, Verônica O; Moraes, Jeremias; Freitas, Mônica Q; Silva, Márcia C; Raices, Renata S L; Sant'Ana, Anderson S; Meireles, M Angela A; Cruz, Adriano G

2018-04-01

This study presents the emerging high-intensity ultrasound (HIUS) processing as a non-thermal alternative to high-temperature short-time pasteurization (HTST). Chocolate milk beverage (CMB) was subjected to different ultrasound energy densities (0.3-3.0 kJ/cm 3 ), as compared to HTST pasteurization (72 °C/15 s) aimed to verify the effect of the HIUS processing on the microbiological and physicochemical characteristics of the beverage. The application of HIUS at an energy density of 3.0 kJ/cm 3 was able to reduce 3.56 ± 0.02 logarithmic cycles in the total aerobic counts. In addition, the ultrasound energy density affected the physical properties of the beverage as the size distribution of fat globule and rheological behavior, as well as the chemical properties such as antioxidant activity, ACE inhibitory activity, fatty acid profile, and volatile profile. In general, the different energetic densities used as a non-thermal method of pasteurization of CMB were more effective when compared to the conventional pasteurization by HTST, since they improved the microbiological and physicochemical quality, besides preserving the bioactive compounds and the nutritional quality of the product. Copyright © 2017 Elsevier B.V. All rights reserved.

Excessive Additive Effect On Engine Oil Viscosity

Directory of Open Access Journals (Sweden)

Vojtěch Kumbár

2014-01-01

Full Text Available The main goal of this paper is excessive additive (for oil filling effect on engine oil dynamic viscosity. Research is focused to commercially distribute automotive engine oil with viscosity class 15W–40 designed for vans. There were prepared blends of new and used engine oil without and with oil additive in specific ratio according manufacturer’s recommendations. Dynamic viscosity of blends with additive was compared with pure new and pure used engine oil. The temperature dependence dynamic viscosity of samples was evaluated by using rotary viscometer with standard spindle. Concern was that the oil additive can moves engine oil of several viscosity grades up. It is able to lead to failure in the engine. Mathematical models were used for fitting experimental values of dynamic viscosity. Exponential fit function was selected, which was very accurate because the coefficient of determination R2 achieved high values (0.98–0.99. These models are able to predict viscosity behaviour blends of engine oil and additive.

Low-density, radiatively inefficient rotating-accretion flow on to a black hole

Science.gov (United States)

Inayoshi, Kohei; Ostriker, Jeremiah P.; Haiman, Zoltán; Kuiper, Rolf

2018-05-01

We study low-density axisymmetric accretion flows on to black holes (BHs) with two-dimensional hydrodynamical simulations, adopting the α-viscosity prescription. When the gas angular momentum is low enough to form a rotationally supported disc within the Bondi radius (RB), we find a global steady accretion solution. The solution consists of a rotational equilibrium distribution around r ˜ RB, where the density follows ρ ∝ (1 + RB/r)3/2, surrounding a geometrically thick and optically thin accretion disc at the centrifugal radius RC(thermal energy generated by viscosity is transported via convection. Physical properties of the inner solution agree with those expected in convection-dominated accretion flows (ρ ∝ r-1/2). In the inner solution, the gas inflow rate decreases towards the centre due to convection (\\dot{M}∝ r), and the net accretion rate (including both inflows and outflows) is strongly suppressed by several orders of magnitude from the Bondi accretion rate \\dot{M}_B. The net accretion rate depends on the viscous strength, following \\dot{M}/\\dot{M}_B∝ (α /0.01)^{0.6}. This solution holds for low accretion rates of \\dot{M}_B/\\dot{M}_Edd≲ 10^{-3} having minimal radiation cooling, where \\dot{M}_Edd is the Eddington accretion rate. In a hot plasma at the bottom (r < 10-3 RB), thermal conduction would dominate the convective energy flux. Since suppression of the accretion by convection ceases, the final BH feeding rate is found to be \\dot{M}/\\dot{M}_B˜ 10^{-3}-10-2. This rate is as low as \\dot{M}/\\dot{M}_Edd˜ 10^{-7}-10-6 inferred for SgrA* and the nuclear BHs in M31 and M87, and can explain their low luminosities, without invoking any feedback mechanism.

A Noncontact Measurement Technique for the Density and Thermal Expansion Coefficient of Solid and Liquid Materials

Science.gov (United States)

Chung, Sang K.; Thiessen, David B.; Rhim, Won-Kyu

1996-01-01

A noncontact measurement technique for the density and the thermal expansion refractory materials in their molten as well as solid phases is presented. This technique is based on the video image processing of a levitated sample. Experiments were performed using the high-temperature electrostatic levitator (HTESL) at the Jet Propulsion Laboratory in which 2-3 mm diameter samples can be levitated, melted, and radiatively cooled in a vacuum. Due to the axisymmetric nature of the molten samples when levitated in the HTESL, a rather simple digital image analysis can be employed to accurately measure the volumetric change as a function of temperature. Density and the thermal expansion coefficient measurements were made on a pure nickel sample to test the accuracy of the technique in the temperature range of 1045-1565 C. The result for the liquid phase density can be expressed by p = 8.848 + (6.730 x 10(exp -4)) x T (degC) g/cu cm within 0.8% accuracy, and the corresponding thermal expansion coefficient can be expressed by Beta=(9.419 x 10(exp -5)) - (7.165 x 10(exp -9) x T (degC)/K within 0.2% accuracy.

Conditions of viscosity measurement for detecting irradiated peppers

International Nuclear Information System (INIS)

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

1995-01-01

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 type of viscometer, shear rate and temperature. (author)

P2O5-doping in waste glasses: evolution of viscosity and crystallization processes

Science.gov (United States)

Tarrago, Mariona; Espuñes, Alex; Garcia-Valles, Maite; Martinez, Salvador

2015-04-01

Current concern for environmental preservation is the main motive for the study of new, more sustainable materials. Increasing amounts of sewage sludge are produced in wastewater treatment plants over the world every day. This fact represents a major problem for the municipalities and industries due to the volume of waste and also to the contaminant elements it may bear, which require expensive conditions for disposal in landfills. Vitrification is an established technique in the inertization of different types of toxic wastes (such as nuclear wastes and contaminated soils) that has been used successfully for sewage sludge. Glasses of basaltic composition (43.48SiO2-14.00Al2O3-12.86Fe2O3-10.00CaO-9.94MgO-3.27Na2O-1.96K2O-0.17MnO-0.55P2O5-2.48TiO2) are used as a laboratory analogous of wastes such as sewage sludge and galvanic sludge to study the properties of the inertization matrix. This basaltic matrix is doped by adding 1%, 2%, 3%, 4% and 20% of P5O5 in order to cover the compositional range of phosphate in sewage sludge encountered in the literature. In this study, the focus has been placed in the effect of the concentration of phosphate (P2O5) in glass stability, thermal properties and evolution of viscosity with temperature. The dependence of viscosity on temperature and the thermal behaviour of these glasses are critical parameters in the design of their production process. Regarding the compositional limits of the mixture, it has been observed that melt reactivity is much increased when P2O5 content is over 4%, hindering the glass conformation process. Moreover, stanfieldite (calcium and magnesium phosphate) crystallized during glass making when phosphate concentration approached 20%, hence establishing the upper limit for glass stability. Viscosity is also dramatically increased in this range, hence requiring production amends. Differential thermal analysis has provided nucleation and crystallization temperatures of the glasses around 915°C and 1050�

Longitudinal and bulk viscosities of expanded rubidium

International Nuclear Information System (INIS)

Zaheri, Ali Hossein Mohammad; Srivastava, Sunita; Tankeshwar, K

2003-01-01

First three non-vanishing sum rules for the bulk and longitudinal stress auto-correlation functions have been evaluated for liquid Rb at six thermodynamic states along the liquid-vapour coexistence curve. The Mori memory function formalism and the frequency sum rules have been used to calculate bulk and longitudinal viscosities. The results thus obtained for the ratio of bulk viscosity to shear viscosity have been compared with experimental and other theoretical predictions wherever available. The values of the bulk viscosity have been found to be more than the corresponding values of the shear viscosity for all six thermodynamic states investigated here

Properties of pure n-butylammonium nitrate ionic liquid and its binary mixtures of with alcohols at T = (293.15 to 313.15) K

International Nuclear Information System (INIS)

Xu, Yingjie; Chen, Bin; Qian, Wu; Li, Haoran

2013-01-01

Highlights: ► Densities and viscosities of (N4NO 3 + alcohols) mixtures were measured. ► Coefficient of thermal expansion, molecular volume, standard entropy, and lattice energy were obtained. ► Excess molar volumes, viscosity deviations, and partial molar volumes were calculated. ► Redlich–Kister polynomial was used to correlate the excess properties. ► The intermolecular interactions between N4NO 3 and alcohols were analysed. -- Abstract: Values of the density and viscosity of the pure ionic liquid n-butylammonium nitrate (N4NO 3 ) and its binary mixtures with methanol, ethanol, 1-propanol, and 1-butanol were measured at temperature ranging from T = (293.15 to 313.15) K. The thermal expansion coefficient, molecular volume, standard entropy, and lattice energy of N4NO 3 were deduced from the experimental density results. The temperature dependence of the viscosity of N4NO 3 was fitted to the fluidity equation. Excess molar volumes V E and viscosity deviations Δη for the binary mixtures were calculated and fitted to the Redlich–Kister equation with satisfactory results. Both excess molar volumes and viscosity deviations show negative deviations for (N4NO 3 + alcohol) mixtures. The effect of the temperature and the size of the alcohol on the excess molar volumes and viscosity deviations are discussed and analysed. Other derived properties, such as the apparent molar volume, partial molar volume, excess partial molar volume, thermal expansion coefficient, and excess thermal expansion coefficient of the above-mentioned systems were also calculated

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.

Viscosity overshoot followed by steady state measured in uni-axial elongation of LDPE. Ole Hassager, Henrik Koblitz Rasmussen, Anders Bach and Jens Kromann Nielsen

DEFF Research Database (Denmark)

Rasmussen, Henrik Koblitz; Hassager, Ole; Bach, Anders

2004-01-01

The transient (e.g. start up of) elongational viscosity of three low-density polyethylene (LDPE) melts (BASF Lupolen 1810H, 1840D and 3020D) was measured using a filament stretching rheometer (FSR) capable of measuring at elevated temperatures. The transient uni-axial elongational viscosity showe...

Dynamic viscosities of 2-butanol with alkanes (C{sub 8}, C{sub 10}, and C{sub 12}) at several temperatures

Energy Technology Data Exchange (ETDEWEB)

Gonzalez, B.; Dominguez, A.; Tojo, J. E-mail: jtojo@uvigo.es

2004-04-01

The dynamic viscosities, densities, and speed of sound for the binary mixtures (2-butanol with octane, or decane, or dodecane) at several temperatures T=(293.15, 298.15, 303.15) K have been measured over the whole composition range and atmospheric pressure along with the properties of the pure components. Excess molar volumes, isentropic compressibility, deviations in isentropic compressibility, and viscosity deviation for the binary systems at the above-mentioned temperatures were calculated and fitted to Redlich-Kister equation to determine the fitting parameters and the root-mean-square deviations. UNIQUAC equation were used to correlate the experimental viscosity data. UNIFAC-VISCO method and ASOG-VISCO method, based on contribution groups, were used to predict the dynamic viscosities of the binary mixtures.

Volumetric, viscometric, spectral studies and viscosity modelling of binary mixtures of esters and alcohols (diethyl succinate, or ethyl octanoate + isobutanol, or isopentanol) at varying temperatures

International Nuclear Information System (INIS)

Majstorović, Divna M.; Živković, Emila M.; Matija, Lidija R.; Kijevčanin, Mirjana Lj.

2017-01-01

Highlights: • Densitis and viscosities of four ester + alcohol binary mixtures were measured. • Excess and deviation functions were calculated. • Fourier transform infrared (FT-IR) spectroscopy analysis was conducted. • Molecular interactions present in the mixture were analyzed. • Viscosity modelling was performed. - Abstract: Density, viscosity and refractive index of four binary mixtures consisting of diethyl succinate or ethyl octanoate + 2-methyl-1-propanol or 3-methyl-1-butanol have been measured at atmospheric pressure and over the temperature range from 288.15 K to 323.15 K. Excess and deviation functions have been calculated from these data and fitted to the Redlich-Kister equation. The values of excess molar volume and deviation functions, with FT-IR study, were further used in the analysis of molecular interactions present in the mixture as well as the temperature influence on them. Molar excess Gibbs free energies of activation of viscous flow were additionally calculated from measured density and viscosity data for better understanding of present molecular interactions. Viscosity modelling was done with two approaches, predictive by group contribution models (UNIFAC-VISCO and ASOG-VISCO), and correlative by one to three-parameter models (Teja-Rice, Grunberg–Nissan, McAlister, Eyring-UNIQUAC and Eyring-NRTL). The obtained results were compared with experimental data and conclusions about applied approaches and models were made.

Experimental analysis of a low cost phase change material emulsion for its use as thermal storage system

International Nuclear Information System (INIS)

Delgado, Mónica; Lázaro, Ana; Mazo, Javier; Peñalosa, Conchita; Dolado, Pablo; Zalba, Belén

2015-01-01

Highlights: • A low cost PCM emulsion has been analyzed as thermal energy storage system. • Its thermophysical and rheological properties have been determined. • The system shows advantages in terms of energy density and heat transfer rate. • The PCM emulsion system has been compared to other thermal energy storage systems. - Abstract: A 46 l commercial tank with a helical coil heat exchanger and containing a low cost phase change material emulsion has been experimentally analyzed as a thermal energy storage system in terms of volumetric energy density and heat transfer rate, for its subsequent comparison with other thermal energy storage systems. This phase change material emulsion shows a phase change temperature range between 30 and 50 °C, its solids content is about 60% with an average particle size of 1 μm. The low cost phase change material emulsion shows a thermal storage capacity by mass 50% higher than water and an increase in viscosity up to 2–5 orders of magnitude. The results have shown that the global heat transfer coefficient of the phase change material emulsion tank is around 2–6 times higher than for conventional latent systems previously analyzed in literature, although 5 times lower than if it contains water. The phase change material emulsion tank presents an energy density 34% higher than the water tank, which makes it a promising solution. Measures to improve its performance are also studied in this work.

Densities, isobaric thermal expansion coefficients and isothermal compressibilities of linear alkylbenzene

International Nuclear Information System (INIS)

Zhou, X; Zhang, Z Y; Zhang, Q M; Liu, Q; Ding, Y Y; Zhou, L; Cao, J

2015-01-01

We report the measurements of the densities of linear alkylbenzene at three temperatures over 4 to 23 °C with pressures up to 10 MPa. The measurements have been analysed to yield the isobaric thermal expansion coefficients and, so far for the first time, isothermal compressibilities of linear alkylbenzene. Relevance of results for current generation (i.e., Daya Bay) and next generation (i.e. JUNO) large liquid scintillator neutrino detectors are discussed. (paper)

An energy stable algorithm for a quasi-incompressible hydrodynamic phase-field model of viscous fluid mixtures with variable densities and viscosities

Science.gov (United States)

Gong, Yuezheng; Zhao, Jia; Wang, Qi

2017-10-01

A quasi-incompressible hydrodynamic phase field model for flows of fluid mixtures of two incompressible viscous fluids of distinct densities and viscosities is derived by using the generalized Onsager principle, which warrants the variational structure, the mass conservation and energy dissipation law. We recast the model in an equivalent form and discretize the equivalent system in space firstly to arrive at a time-dependent ordinary differential and algebraic equation (DAE) system, which preserves the mass conservation and energy dissipation law at the semi-discrete level. Then, we develop a temporal discretization scheme for the DAE system, where the mass conservation and the energy dissipation law are once again preserved at the fully discretized level. We prove that the fully discretized algorithm is unconditionally energy stable. Several numerical examples, including drop dynamics of viscous fluid drops immersed in another viscous fluid matrix and mixing dynamics of binary polymeric solutions, are presented to show the convergence property as well as the accuracy and efficiency of the new scheme.

Non-perturbative unitarity constraints on the ratio of shear viscosity to entropy density in UV complete theories with a gravity dual

CERN Document Server

Brustein, Ram

2011-01-01

We reconsider, from a novel perspective, how unitarity constrains the corrections to the ratio of shear viscosity \\eta\\ to entropy density s. We start with higher-derivative extensions of Einstein gravity in asymptotically anti-de Sitter spacetimes. It is assumed that these theories are derived from string theory and thus have a unitary UV completion that is dual to a unitary, UV-complete boundary gauge theory. We then propose that the gravitational perturbations about a solution of the UV complete theory are described by an effective theory whose linearized equations of motion have at most two time derivatives. Our proposal leads to a concrete prescription for the calculation of \\eta/s for theories of gravity with arbitrary higher-derivative corrections. The resulting ratio can take on values above or below 1/4\\pi\\ and is consistent with all the previous calculations, even though our reasoning is substantially different. For the purpose of calculating \\eta/s, our proposal also leads to only two possible cand...

The Friction Theory for Viscosity Modeling

DEFF Research Database (Denmark)

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

2001-01-01

, 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......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...

Evaluation of thermal conductivity for liquid lead lithium alloys at various Li concentrations based on measurement and evaluation of density, thermal diffusivity and specific heat of alloys

Energy Technology Data Exchange (ETDEWEB)

Kondo, Masatoshi, E-mail: kondo.masatoshi@nr.titech.ac.jp [Tokyo Institute of Technology, 2-12-1, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8550 (Japan); Nakajima, Yuu; Tsuji, Mitsuyo [Tokai University, 4-1-1 Kitakaname, Hiratsuka-shi, Kanagawa 259-1292 (Japan); Nozawa, Takashi [Japan Atomic Energy Agency, Rokkasyo-mura, Kamikita-gun, Aomori 039-3212 (Japan)

2016-11-01

Graphical abstract: Thermal diffusivities and thermal conductivities of liquid Pb–Li alloys (Pb–5Li, Pb–11Li and Pb–17Li). - Highlights: • The densities and specific heats of liquid Pb–Li alloys are evaluated based on the previous studies, and mathematically expressed in the equations with the functions of temperature and Li concentration. • The thermal diffusivities of liquid Pb–Li alloys (i.e., Pb–5Li, Pb–11Li and Pb–17Li) are obtained by laser flash method, and mathematically expressed in the equations with the functions of temperature and Li concentration. • The thermal conductivities of liquid Pb–Li alloys were evaluated and mathematically expressed in the equations with the functions of temperature and Li concentration. - Abstract: The thermophysical properties of lead lithium alloy (Pb–Li) are essential for the design of liquid Pb–Li blanket system. The purpose of the present study is to make clear the density, the thermal diffusivity and the heat conductivity of the alloys as functions of temperature and Li concentration. The densities of the solid alloys were measured by means of the Archimedean method. The densities of the alloys at 300 K as a function of Li concentration (0 at% < χ{sub Li} < 28 at%) were obtained in the equation as ρ{sub (300} {sub K)} [g/cm{sup 3}] = −6.02 × 10{sup −2} × χ{sub Li} + 11.3. The density of the liquid alloys was formulated as functions of temperature and Li concentration (0 at% < χ{sub Li} < 30 at%), and expressed in the equation as ρ [g/cm{sup 3}] = (9.00 × 10{sup −6} × T − 7.01 × 10{sup −2}) × χ{sub Li} + 11.4 − 1.19 × 10{sup −3}T. The thermal diffusivity of Pb, Pb–5Li, Pb–11Li and Pb–17Li were measured by means of laser flash method. The thermal diffusivity of Pb–17Li was obtained in the equation as α{sub Pb–17Li} [cm{sup 2}/s] = 3.46 × 10{sup −4}T + 1.05 × 10{sup −1} for the temperature range between 573 K and 773 K. The thermal conductivity of

Quantum entanglement and thermal reduced density matrices in fermion and spin systems on ladders

International Nuclear Information System (INIS)

Chen, Xiao; Fradkin, Eduardo

2013-01-01

Numerical studies of the reduced density matrix of a gapped spin-1/2 Heisenberg antiferromagnet on a two-leg ladder find that it has the same form as the Gibbs density matrix of a gapless spin-1/2 Heisenberg antiferromagnetic chain at a finite temperature determined by the spin gap of the ladder. We investigate this interesting result by considering a model of free fermions on a two-leg ladder (gapped by the inter-chain tunneling operator) and in spin systems on a ladder with a gapped ground state using exact solutions and several controlled approximations. We calculate the reduced density matrix and the entanglement entropy for a leg of the ladder (i.e. a cut made between the chains). In the fermionic system we find the exact form of the reduced density matrix for one of the chains and determine the entanglement spectrum explicitly. Here we find that in the weak tunneling limit of the ladder the entanglement entropy of one chain of the gapped ladder has a simple and universal form dictated by conformal invariance. In the case of the spin system, we consider the strong coupling limit by using perturbation theory and get the reduced density matrix by the Schmidt decomposition. The entanglement entropies of a general gapped system of two coupled conformal field theories (in 1 + 1 dimensions) are discussed using the replica trick and scaling arguments. We show that (1) for a system with a bulk gap the reduced density matrix has the form of a thermal density matrix, (2) the long-wavelength modes of one subsystem (a chain) of a gapped coupled system are always thermal, (3) the von Neumann entropy equals the thermodynamic entropy of one chain, and (4) the bulk gap plays the role of effective temperature. (paper)

Rational design of viscosity reducing mutants of a monoclonal antibody: hydrophobic versus electrostatic inter-molecular interactions.

Science.gov (United States)

Nichols, Pilarin; Li, Li; Kumar, Sandeep; Buck, Patrick M; Singh, Satish K; Goswami, Sumit; Balthazor, Bryan; Conley, Tami R; Sek, David; Allen, Martin J

2015-01-01

High viscosity of monoclonal antibody formulations at concentrations ≥100 mg/mL can impede their development as products suitable for subcutaneous delivery. The effects of hydrophobic and electrostatic intermolecular interactions on the solution behavior of MAB 1, which becomes unacceptably viscous at high concentrations, was studied by testing 5 single point mutants. The mutations were designed to reduce viscosity by disrupting either an aggregation prone region (APR), which also participates in 2 hydrophobic surface patches, or a negatively charged surface patch in the variable region. The disruption of an APR that lies at the interface of light and heavy chain variable domains, VH and VL, via L45K mutation destabilized MAB 1 and abolished antigen binding. However, mutation at the preceding residue (V44K), which also lies in the same APR, increased apparent solubility and reduced viscosity of MAB 1 without sacrificing antigen binding or thermal stability. Neutralizing the negatively charged surface patch (E59Y) also increased apparent solubility and reduced viscosity of MAB 1, but charge reversal at the same position (E59K/R) caused destabilization, decreased solubility and led to difficulties in sample manipulation that precluded their viscosity measurements at high concentrations. Both V44K and E59Y mutations showed similar increase in apparent solubility. However, the viscosity profile of E59Y was considerably better than that of the V44K, providing evidence that inter-molecular interactions in MAB 1 are electrostatically driven. In conclusion, neutralizing negatively charged surface patches may be more beneficial toward reducing viscosity of highly concentrated antibody solutions than charge reversal or aggregation prone motif disruption.

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.

VISCOSITY DICTATES METABOLIC ACTIVITY of Vibrio ruber

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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.

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.)

Bulk viscosity of spin-one color superconductors

International Nuclear Information System (INIS)

Sa'd, Basil A.

2009-01-01

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.)

Viscosity of particle laden films

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Timounay Yousra

2017-01-01

Full Text Available 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.

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.

Thermal Experimental Analysis for Dielectric Characterization of High Density Polyethylene Nanocomposites

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Ahmed Thabet Mohamed

2016-01-01

Full Text Available The importance of nanoparticles in controlling physical properties of polymeric nanocomposite materials leads us to study effects of these nanoparticles on electric and dielectric properties of polymers in industry In this research, the dielectric behaviour of High-Density Polyethylene (HDPE nanocomposites materials that filled with nanoparticles of clay or fumed silica has been investigated at various frequencies (10 Hz-1 kHz and temperatures (20-60°C. Dielectric spectroscopy has been used to characterize ionic conduction, then, the effects of nanoparticles concentration on the dielectric losses and capacitive charge of the new nanocomposites can be stated. Capacitive charge and loss tangent in high density polyethylene nanocomposites are measured by dielectric spectroscopy. Different dielectric behaviour has been observed depending on type and concentration of nanoparticles under variant thermal conditions.

VISCOSE BASED MAGNETIC YARNS – PHYSICAL AND MECHANICAL CHARACTERIZATION

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GROSU Marian-Cătălin

2017-05-01

Full Text Available In the context of the rapid growth in the number of electrical and electronic devices and accessories that emit electromagnetic energy in different frequency bands we present and characterize here several magnetic functionalized viscose twisted yarns. A 100% viscose twisted staple yarn was covered through an in-house developed process with a polymeric solution containing micrometric sized barium hexaferrite magnetic powder. The in-house developed process allows deposition of micrometric thickness polymeric paste layer on the yarn surface. Barium hexaferrite is a hard magnetic material exhibiting high chemical stability and corrosion resistivity, relatively large saturation and residual magnetization and microwave absorbing properties. Five different percentages of the magnetic powder in the polymer solution were used, i.e. ranging from 15 wt% to 45 wt%. Physical characterization shows a very good adherence between the highly hygroscopic viscose staple fibers and the polymeric solution that contains polyvinyl acetate and polyurethane as binders. SEM images evidenced the fact that the polymeric solution penetrated more than 1/3 of the yarn diameter. The concentration of magnetic powder in the polymeric solution has a direct influence on the coating amount, diameter and density. The mechanical characterization of the coated yarns revealed that the breaking force is increasing with increasing magnetic powder content up to o certain value and then decreased because the magnetic layer became stiffer. At the same time, the elongation at brake is decreasing.

Longitudinal and bulk viscosities of Lennard-Jones fluids

Science.gov (United States)

Tankeshwar, K.; Pathak, K. N.; Ranganathan, S.

1996-12-01

Expressions for the longitudinal and bulk viscosities have been derived using Green Kubo formulae involving the time integral of the longitudinal and bulk stress autocorrelation functions. The time evolution of stress autocorrelation functions are determined using the Mori formalism and a memory function which is obtained from the Mori equation of motion. The memory function is of hyperbolic secant form and involves two parameters which are related to the microscopic sum rules of the respective autocorrelation function. We have derived expressions for the zeroth-, second-and fourth- order sum rules of the longitudinal and bulk stress autocorrelation functions. These involve static correlation functions up to four particles. The final expressions for these have been put in a form suitable for numerical calculations using low- order decoupling approximations. The numerical results have been obtained for the sum rules of longitudinal and bulk stress autocorrelation functions. These have been used to calculate the longitudinal and bulk viscosities and time evolution of the longitudinal stress autocorrelation function of the Lennard-Jones fluids over wide ranges of densities and temperatures. We have compared our results with the available computer simulation data and found reasonable agreement.

Dewetting of low-viscosity films at solid/liquid interfaces.

Science.gov (United States)

Péron, Nicolas; Brochard-Wyart, Françoise; Duval, Hervé

2012-11-13

We report new experimental results on the dewetting of a mercury film (A) intercalated between a glass slab and an external nonmiscible liquid phase (B) under conditions of a large equilibrium contact angle. The viscosity of the external phase, ηB, was varied over 7 orders of magnitude. We observe a transition between two regimes of dewetting at a threshold viscosity of η(B)* ≈ (ρ(A)e|S̃|)(1/2), where ρ(A) is the mercury density, e is the film thickness, and |S̃| is the effective spreading coefficient. For η(B) dewetting is constant and ruled by Culick’s law, V ≈ (|S̃|/(ρ(A)e))(1/2). Capillary waves were observed at high dewetting velocities: they are a signature of hydraulic shock. For η(B) > η(B)*, the regime is viscous. The dewetting velocity is constant and scales as V ≈ |S̃|/η(B) in the limit of large η(B). We interpret this regime by a balance between the surface energy released during dewetting and the viscous dissipation in the surrounding liquid.

DC Thermal Plasma Design and Utilization for the Low Density Polyethylene to Diesel Oil Pyrolysis Reaction

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Hossam A. Gabbar

2017-06-01

Full Text Available The exponential increase of plastic production produces 100 million tonnes of waste plastics annually which could be converted into hydrocarbon fuels in a thermal cracking process called pyrolysis. In this research work, a direct current (DC thermal plasma circuit is designed and used for conversion of low density polyethylene (LDPE into diesel oil in a laboratory scale pyrolysis reactor. The experimental setup uses a 270 W DC thermal plasma at operating temperatures in the range of 625 °C to 860 °C for a low density polyethylene (LDPE pyrolysis reaction at pressure = −0.95, temperature = 550 °C with τ = 30 min at a constant heating rate of 7.8 °C/min. The experimental setup consists of a vacuum pump, closed system vessel, direct current (DC plasma circuit, and a k-type thermocouple placed a few millimeters from the reactant sample. The hydrocarbon products are condensed to diesel oil and analyzed using flame ionization detector (FID gas chromatography. The analysis shows 87.5% diesel oil, 1,4-dichlorobenzene (Surr, benzene, ethylbenzene and traces of toluene and xylene. The direct current (DC thermal plasma achieves 56.9 wt. % of diesel range oil (DRO, 37.8 wt. % gaseous products and minimal tar production. The direct current (DC thermal plasma shows reliability, better temperature control, and high thermal performance as well as the ability to work for long operation periods.

The effect of ilmenite viscosity on the dynamics and evolution of an overturned lunar cumulate mantle

Science.gov (United States)

Zhang, Nan; Dygert, Nick; Liang, Yan; Parmentier, E. M.

2017-07-01

Lunar cumulate mantle overturn and the subsequent upwelling of overturned mantle cumulates provide a potential framework for understanding the first-order thermochemical evolution of the Moon. Upwelling of ilmenite-bearing cumulates (IBCs) after the overturn has a dominant influence on the dynamics and long-term thermal evolution of the lunar mantle. An important parameter determining the stability and convective behavior of the IBC is its viscosity, which was recently constrained through rock deformation experiments. To examine the effect of IBC viscosity on the upwelling of overturned lunar cumulate mantle, here we conduct three-dimensional mantle convection models with an evolving core superposed by an IBC-rich layer, which resulted from mantle overturn after magma ocean solidification. Our modeling shows that a reduction of mantle viscosity by 1 order of magnitude, due to the presence of ilmenite, can dramatically change convective planform and long-term lunar mantle evolution. Our model results suggest a relatively stable partially molten IBC layer that has surrounded the lunar core to the present day.Plain Language SummaryThe Moon's mantle is locally ilmenite rich. Previous models exploring the convective evolution of the lunar mantle did not consider the effects of ilmenite viscosity. Recent rock deformation experiments demonstrate that Fe-Ti oxide (ilmenite) is a low viscosity phase compared to olivine and other silicate minerals. Our modeling shows that ilmenite changes the lunar mantle plume process. An ilmenite-rich layer around the lunar core would be highly stable throughout geologic time, consistent with a partially molten, low viscosity layer around the core inferred from seismic attenuation and tidal dissipation.

From strong to weak coupling in holographic models of thermalization

Energy Technology Data Exchange (ETDEWEB)

Grozdanov, Sašo; Kaplis, Nikolaos [Instituut-Lorentz for Theoretical Physics, Leiden University,Niels Bohrweg 2, Leiden 2333 CA (Netherlands); Starinets, Andrei O. [Rudolf Peierls Centre for Theoretical Physics, University of Oxford,1 Keble Road, Oxford OX1 3NP (United Kingdom)

2016-07-29

We investigate the analytic structure of thermal energy-momentum tensor correlators at large but finite coupling in quantum field theories with gravity duals. We compute corrections to the quasinormal spectra of black branes due to the presence of higher derivative R{sup 2} and R{sup 4} terms in the action, focusing on the dual to N=4 SYM theory and Gauss-Bonnet gravity. We observe the appearance of new poles in the complex frequency plane at finite coupling. The new poles interfere with hydrodynamic poles of the correlators leading to the breakdown of hydrodynamic description at a coupling-dependent critical value of the wave-vector. The dependence of the critical wave vector on the coupling implies that the range of validity of the hydrodynamic description increases monotonically with the coupling. The behavior of the quasinormal spectrum at large but finite coupling may be contrasted with the known properties of the hierarchy of relaxation times determined by the spectrum of a linearized kinetic operator at weak coupling. We find that the ratio of a transport coefficient such as viscosity to the relaxation time determined by the fundamental non-hydrodynamic quasinormal frequency changes rapidly in the vicinity of infinite coupling but flattens out for weaker coupling, suggesting an extrapolation from strong coupling to the kinetic theory result. We note that the behavior of the quasinormal spectrum is qualitatively different depending on whether the ratio of shear viscosity to entropy density is greater or less than the universal, infinite coupling value of ℏ/4πk{sub B}. In the former case, the density of poles increases, indicating a formation of branch cuts in the weak coupling limit, and the spectral function shows the appearance of narrow peaks. We also discuss the relation of the viscosity-entropy ratio to conjectured bounds on relaxation time in quantum systems.

Excess molar volumes and dynamic viscosities for binary mixtures of toluene + n-alkanes (C5-C10) at T = 298.15 K - Comparison with Prigogine-Flory-Patterson theory

International Nuclear Information System (INIS)

Iloukhani, Hossein; Rezaei-Sameti, Mahdi; Basiri-Parsa, Jalal

2006-01-01

Densities ρ, dynamic viscosities η, for binary mixtures of toluene with some n-alkanes, namely, n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane have been measured over the complete composition range. Excess molar volumes V E , viscosity deviations Δη, and excess Gibbs free energy of activation ΔG * E , were calculated there from and were correlated by Redlich-Kister type function in terms of mole fractions. For mixtures of toluene with n-pentane and n-hexane the V E is negative and for the remaining systems is positive. The Δη values are negative for all the studied mixtures. The ΔG * E values shows the positive values for the binary mixtures with n-decane, whereas the negative values have been observed for all the remaining binary mixtures. From the results, the excess thermal expansivities at constant pressure α E , is also estimated. The Prigogine-Flory-Patterson (PFP) theory and its applicability in predicting V E is tested. The results obtained for viscosity of binary mixtures were used to test the semi-empirical relations of Grunberg and Nissan, Tamura and Kurata, Hind et al., Katti and Chaudhri, McAllister, Heric, Kendall, and Monroe. The experimental on the constituted binaries are analyzed to discus the nature and strength of intermolecular interactions in these mixtures

Effect of block composition on thermal properties and melt viscosity of poly[2-(dimethylaminoethyl methacrylate], poly(ethylene oxide and poly(propylene oxide block co-polymers

Directory of Open Access Journals (Sweden)

2011-09-01

Full Text Available To modify the rheological properties of certain commercial polymers, a set of block copolymers were synthesized through oxyanionic polymerization of 2-(dimethylaminoethyl methacrylate to the chain ends of commercial prepolymers, namely poly(ethylene oxide (PEO, poly(ethylene oxide-block-poly(propylene oxide-block-poly(ethylene oxide (PEO-PPO-PEO, and poly(propylene oxide (PPO. The formed block copolymers were analysed with size exclusion chromatography and nuclear magnetic resonance spectroscopy in order to confirm block formation. Thermal characterization of the resulting polymers was done with differential scanning calorimetry. Thermal transition points were also confirmed with rotational rheometry, which was primarily used to measure melt strength properties of the resulting block co-polymers. It was observed that the synthesised poly[2-(dimethylaminoethyl methacrylate]-block (PDM affected slightly the thermal transition points of crystalline PEO-block but the influence was stronger on amorphous PPO-blocks. Frequency sweeps measured above the melting temperatures for the materials confirmed that the pre-polymers (PEO and PEO-PPO-PEO behave as Newtonian fluids whereas polymers with a PDM block structure exhibit clear shear thinning behaviour. In addition, the PDM block increased the melt viscosity when compared with that one of the pre-polymer. As a final result, it became obvious that pre-polymers modified with PDM were in entangled form, in the melted state as well in the solidified form.

Physical Properties and Thermal Decomposition of Aqueous Solutions of 2-Amino-2-hydroxymethyl-1, 3-propanediol (AHPD)

Science.gov (United States)

Murshid, Ghulam; Shariff, Azmi Mohd; Lau, K. K.; Bustam, Mohammad Azmi; Ahmad, Faizan

2011-10-01

Physical properties such as density, viscosity, refractive index, surface tension, and thermal stability of 2-amino-2-hydroxymethyl-1,3-propanediol (AHPD) were experimentally measured. All the experimental measurements were made over a wide range of temperatures from (298.15 to 333.15) K and AHPD concentrations of (1, 7, 13, 19, and 25) mass%. An overall decrease in all the measured physical properties was observed with increasing temperature. The experimental results are presented as a function of temperature and AHPD mass fraction. All the measured physical properties were correlated as a function of temperature. Thermal decomposition of pure and aqueous solutions of AHPD was investigated using a thermo-gravimetric analyzer (TGA) at a heating rate of 10 K · min-1.

In situ viscometry by optical trapping interferometry

DEFF Research Database (Denmark)

Guzmán, C.; Flyvbjerg, Henrik; Köszali, R.

2008-01-01

We demonstrate quantitative in situ viscosity measurements by tracking the thermal fluctuations of an optically trapped microsphere subjected to a small oscillatory flow. The measured power spectral density of the sphere's positions displays a characteristic peak at the driving frequency of the f......We demonstrate quantitative in situ viscosity measurements by tracking the thermal fluctuations of an optically trapped microsphere subjected to a small oscillatory flow. The measured power spectral density of the sphere's positions displays a characteristic peak at the driving frequency...

The thermal and mechanical properties of a low-density glass-fiber-reinforced elastomeric ablation material

Science.gov (United States)

Engelke, W. T.; Robertson, R. W.; Bush, A. L.; Pears, C. D.

1974-01-01

An evaluation of the thermal and mechanical properties was performed on a molded low-density elastomeric ablation material designated as Material B. Both the virgin and charred states were examined to provide meaningful inputs to the design of a thermal protection system. Chars representative of the flight chars formed during ablation were prepared in a laboratory furnace from 600 K to 1700 K and properties of effective thermal conductivity, heat capacity, porosity and permeability were determined on the furnace chars formed at various temperature levels within the range. This provided a boxing of the data which will enable the prediction of the transient response of the material during flight ablation.

Thermal Expansion and Density Data of UO2 and Simulated Fuel for Standard Reference

International Nuclear Information System (INIS)

Yang, Jae Hwan; Na, S. H.; Lee, J. W.; Kang, K. H.

2010-01-01

Standard Reference Data (SRD) is the scientific, technical data whose reliability and accuracy are evaluated by scientist group. Since SRD has a great impact on the improvement of national competitiveness by stirring up technological innovation in every sector of industries, many countries are making great efforts on establishing SRD in various areas. Data center for nuclear fuel material in Korea Atomic Energy Research Institute plays a role to providing property data of nuclear fuel material at high temperature, pressure, and radiation which are essential for the safety evaluation of nuclear power. In this study, standardization of data on thermal expansion and density of UO 2 were carried out in the temperature range from 300 K to 3100 K via uncertainty evaluation of indirectly produced data. Besides, standardization of data on thermal expansion and density of simulated fuel were also done in the temperature range from 350 K to 1750 K via uncertainty evaluation of directly produced data

Convection Heat Transfer Modeling of Ag Nanofluid Using Different Viscosity Theories

Directory of Open Access Journals (Sweden)

Ali Bakhsh Kasaeian

2012-04-01

Full Text Available ABSTRACT: In this paper, the effects of adding nanoparticles (including Ag to a fluid media for improving free convection heat transfer were analysed. The free convective heat transfer was assumed to be in laminar flow regime, and the corresponding calculations and solutions were all done by the integral method. Water, as a Newtonian fluid, was considered as the base and all relevant thermo physical properties of the nanofluids were considered to be unvarying. The calculations performed and the graphs generated showed that, in general, the addition of nanoparticles to the fluid media resulted in an increment or improvement of its heat transfer coefficient. With increase in the concentration of the nanoparticles, the heat transfer rate of the fluid also increased. The increment in heat transfer is also dependent on the nanoparticles’ thermal conductivity and the viscosity theory which was utilized in the calculations. In this study, four different theories were used to calculate the viscosities of the nanofluids. The effects of viscosity on the nanofluids’ thermal conductivity were apparent from the calculations which were performed for nanoparticle concentrations of 4% or less. ABSTRAK: Kajian ini menganalisis kesan penambahan nanopartikel Ag ke dalam media bendalir bagi tujuan pembaikkan pemindahan haba perolakan bebas. Perolakan bebas diandaikan berada di zon aliran laminar, di mana penyelesaian dan pengiraan telah dilakukan mengunakan kaedah kamilan. Air yang merupakan cecair Newtonian, dianggap sebagai asas dan sifat terma fizikal nanocecair dianggapkan tidak berubah. Mengikut pengiraan yang dilakukan dan graf yang diplotkan, umumnya penambahan nanopartikel kepada media bendalir menyebabkan peningkatan dan pengembangan pekali pemindahan haba. Kadar pemindahan haba meningkat dengan nanopartikel. Peningkatan pemindahan haba juga bergantung kepada pengalir haba nanopartikel dan teori kelikatan yang digunakan. Di dalam kajian ini, empat

Large-scale thermal convection of viscous fluids in a faulted system: 3D test case for numerical codes

Science.gov (United States)

Magri, Fabien; Cacace, Mauro; Fischer, Thomas; Kolditz, Olaf; Wang, Wenqing; Watanabe, Norihiro

2017-04-01

In contrast to simple homogeneous 1D and 2D systems, no appropriate analytical solutions exist to test onset of thermal convection against numerical models of complex 3D systems that account for variable fluid density and viscosity as well as permeability heterogeneity (e.g. presence of faults). Owing to the importance of thermal convection for the transport of energy and minerals, the development of a benchmark test for density/viscosity driven flow is crucial to ensure that the applied numerical models accurately simulate the physical processes at hands. The presented study proposes a 3D test case for the simulation of thermal convection in a faulted system that accounts for temperature dependent fluid density and viscosity. The linear stability analysis recently developed by Malkovsky and Magri (2016) is used to estimate the critical Rayleigh number above which thermal convection of viscous fluids is triggered. The numerical simulations are carried out using the finite element technique. OpenGeoSys (Kolditz et al., 2012) and Moose (Gaston et al., 2009) results are compared to those obtained using the commercial software FEFLOW (Diersch, 2014) to test the ability of widely applied codes in matching both the critical Rayleigh number and the dynamical features of convective processes. The methodology and Rayleigh expressions given in this study can be applied to any numerical model that deals with 3D geothermal processes in faulted basins as by example the Tiberas Basin (Magri et al., 2016). References Kolditz, O., Bauer, S., Bilke, L., Böttcher, N., Delfs, J. O., Fischer, T., U. J. Görke, T. Kalbacher, G. Kosakowski, McDermott, C. I., Park, C. H., Radu, F., Rink, K., Shao, H., Shao, H.B., Sun, F., Sun, Y., Sun, A., Singh, K., Taron, J., Walther, M., Wang,W., Watanabe, N., Wu, Y., Xie, M., Xu, W., Zehner, B., 2012. OpenGeoSys: an open-source initiative for numerical simulation of thermo-hydro-mechanical/chemical (THM/C) processes in porous media. Environmental

Effects of polymer-nanoparticle interactions on the viscosity of unentangled polymers under extreme nanoconfinement during capillary rise infiltration.

Science.gov (United States)

Hor, Jyo Lyn; Wang, Haonan; Fakhraai, Zahra; Lee, Daeyeon

2018-03-28

We explore the effect of confinement and polymer-nanoparticle interactions on the viscosity of unentangled polymers undergoing capillary rise infiltration (CaRI) in dense packings of nanoparticles. In CaRI, a polymer is thermally induced to wick into the dense packings of nanoparticles, leading to the formation of polymer-infiltrated nanoparticle films, a new class of thin film nanocomposites with extremely high concentrations of nanoparticles. To understand the effect of this extreme nanoconfinement, as well as polymer-nanoparticle interactions on the polymer viscosity in CaRI films, we use two polymers that are known to have very different interactions with SiO2 nanoparticles. Using in situ spectroscopic ellipsometry, we monitor the polymer infiltration process, from which we infer the polymer viscosity based on the Lucas-Washburn model. Our results suggest that physical confinement increases the viscosity by approximately two orders of magnitude. Furthermore, confinement also increases the glass transition temperature of both polymers. Thus, under extreme nanoconfinement, the physical confinement has a more significant impact than the polymer-nanoparticle interactions on the viscosity of unentangled polymers, measured through infiltration dynamics, as well as the glass transition temperature. These findings will provide fundamental frameworks for designing processes to enable the fabrication of CaRI nanocomposite films with a wide range of nanoparticles and polymers.

Dissepiments, density bands and signatures of thermal stress in Porites skeletons

Science.gov (United States)

DeCarlo, Thomas M.; Cohen, Anne L.

2017-09-01

The skeletons of many reef-building corals are accreted with rhythmic structural patterns that serve as valuable sclerochronometers. Annual high- and low-density band couplets, visible in X-radiographs or computed tomography scans, are used to construct age models for paleoclimate reconstructions and to track variability in coral growth over time. In some corals, discrete, anomalously high-density bands, called "stress bands," preserve information about coral bleaching. However, the mechanisms underlying the formation of coral skeletal density banding remain unclear. Dissepiments—thin, horizontal sheets of calcium carbonate accreted by the coral to support the living polyp—play a key role in the upward growth of the colony. Here, we first conducted a vital staining experiment to test whether dissepiments were accreted with lunar periodicity in Porites coral skeleton, as previously hypothesized. Over 6, 15, and 21 months, dissepiments consistently formed in a 1:1 ratio to the number of full moons elapsed over each study period. We measured dissepiment spacing to reconstruct multiple years of monthly skeletal extension rates in two Porites colonies from Palmyra Atoll and in another from Palau that bleached in 1998 under anomalously high sea temperatures. Spacing between successive dissepiments exhibited strong seasonality in corals containing annual density bands, with narrow (wide) spacing associated with high (low) density, respectively. A high-density "stress band" accreted during the 1998 bleaching event was associated with anomalously low dissepiment spacing and missed dissepiments, implying that thermal stress disrupts skeletal extension. Further, uranium/calcium ratios increased within stress bands, indicating a reduction in the carbonate ion concentration of the coral's calcifying fluid under stress. Our study verifies the lunar periodicity of dissepiments, provides a mechanistic basis for the formation of annual density bands in Porites, and reveals the

Viscose kink and drift-kink modes in a tokamak

International Nuclear Information System (INIS)

Kuvshinov, B.N.; Mikhajlovskij, A.B.

1988-01-01

Intristic kink modes in a tokamak are theoretically investigated taking account of longitudinal viscosity of ions and electrons and drift effect. It is marked that dispersion equation of investigated modes coinsides in form with that for ballooning modes. It is shown that five types of intrinsic kink instability may be distinguished in disregard of viscosity and drift effects. Effect of stabilizing quasiideal viscose kink and viscose resistive kink modes by finite Larmuir ion radius is investigated. A branch of viscose reclosure mode which instability is due to electron viscosity is pointed out. A series of other viscose and drift-kink tokamak modes is considered. Both general disperse equations of the above-mentioned kink instability varieties, taking account of viscose and drift ones, and disperse equations of separate branches are presented

Dynamical properties and transport coefficients of one-dimensional Lennard-Jones fluids: A molecular dynamics study

Science.gov (United States)

Bazhenov, Alexiev M.; Heyes, David M.

1990-01-01

The thermodynamics, structure, and transport coefficients, as defined by the Green-Kubo integrals, of the one-dimensional Lennard-Jones fluid are evaluated for a wide range of state points by molecular dynamics computer simulation. These calculations are performed for the first time for thermal conductivity and the viscosity. We observe a transition from hard-rod behavior at low number density to harmonic-spring fluid behavior in the close-packed limit. The self-diffusion coefficient decays with increasing density to a finite limiting value. The thermal conductivity increases with density, tending to ∞ in the close-packed limit. The viscosity in contrast maximizes at intermediate density, tending to zero in the zero density and close-packed limits.

Subducted slabs and lateral viscosity variations: effects on the long-wavelength geoid

Science.gov (United States)

Tosi, Nicola; Čadek, Ondřej; Martinec, Zdeněk

2009-11-01

The characteristic broad local maxima exhibited by the long-wavelength geoid over subduction zones are investigated with a numerical model of mantle flow. In a spherical axisymmetric geometry, a synthetic model of buoyancy driven subduction is used to test the effects on the geoid caused by the depth of penetration of the lithosphere into the mantle, by the viscosity stratification and by lateral viscosity variations (LVV) in the lithosphere, upper and lower mantle. The presence of anomalous slab density in the lower mantle guarantees geoid amplitudes comparable with the observations, favouring the picture of slabs that penetrate the transition zone and sink into the deep mantle. The viscosity of the lower mantle controls the long-wavelength geoid to the first order, ensuring a clear positive signal when it is at least 30-times greater than the upper-mantle viscosity. The presence of LVV in the lithosphere, in the form of weak plate margins, helps to increase the contribution of the surface topography, causing a pronounced reduction of the geoid. Localized LVV associated with the cold slab play a secondary role if they are in the upper mantle. On the other hand, highly viscous slabs in the lower mantle exert a large influence on the geoid. They cause its amplitude to increase dramatically, way beyond the values typically observed over subduction zones. Long-wavelength flow becomes less vigorous as the slab viscosity increases. Deformation in the upper mantle becomes more localized and power is transferred to short wavelengths, causing the long-wavelength surface topography to diminish and the total geoid to increase. Slabs may be then weakened in the lower mantle or retain their high viscosity while other mechanisms act to lower the geoid. It is shown that a phase change from perovskite to post-perovskite above the core-mantle boundary can cause the geoid to reduce significantly, thereby helping to reconcile models and observations.

VISCOSITY TEST OF VEHICLE ENGINE OILS

OpenAIRE

Rita Prasetyowati

2016-01-01

This study aims to determine the value of the kinematic viscosity lubricants motorcycle that has been used at various temperatures and the use of distance. This study also aims to remedy mengtahui how the value of the kinematic viscosity of the lubricant car that has been used in a wide range of temperature variation and distance usage. Viscosity liquid, in this case is the lubricants, can be determined using the Redwood viscometer By using Redwood viscometer, can be measured flow time requir...

Multiscale modeling of electroosmotic flow: Effects of discrete ion, enhanced viscosity, and surface friction

Science.gov (United States)

Bhadauria, Ravi; Aluru, N. R.

2017-05-01

We propose an isothermal, one-dimensional, electroosmotic flow model for slit-shaped nanochannels. Nanoscale confinement effects are embedded into the transport model by incorporating the spatially varying solvent and ion concentration profiles that correspond to the electrochemical potential of mean force. The local viscosity is dependent on the solvent local density and is modeled using the local average density method. Excess contributions to the local viscosity are included using the Onsager-Fuoss expression that is dependent on the local ionic strength. A Dirichlet-type boundary condition is provided in the form of the slip velocity that is dependent on the macroscopic interfacial friction. This solvent-surface specific interfacial friction is estimated using a dynamical generalized Langevin equation based framework. The electroosmotic flow of Na+ and Cl- as single counterions and NaCl salt solvated in Extended Simple Point Charge (SPC/E) water confined between graphene and silicon slit-shaped nanochannels are considered as examples. The proposed model yields a good quantitative agreement with the solvent velocity profiles obtained from the non-equilibrium molecular dynamics simulations.

Extremely high-power-density atmospheric-pressure thermal plasma jet generated by the nitrogen-boosted effect

Science.gov (United States)

Hanafusa, Hiroaki; Nakashima, Ryosuke; Nakano, Wataru; Higashi, Seiichiro

2018-06-01

In this study, the effect of N2 addition to an atmospheric-pressure Ar thermal plasma jet (TPJ) on ultrarapid heating was investigated. With increasing N2 flow rate, a boost of arc voltage to ∼36 V was observed, which significantly improved heating characteristics. As a result, a drastic power density increase from 10 to 125 kW/cm2 was achieved with the addition of 2.0 L/min N2 to 3.0 L/min Ar. The results of optical emission analysis and heating characteristics evaluation implied that dissociation and recombination of N2 molecules and the high thermal transport property of nitrogen gas play important roles in the increase in TPJ power density. Furthermore, we obtained TPJ extension with N2 addition that reached 300 mm, and it showed spatial enhancement of heat transport characteristics.

Analytical thermal modelling of multilayered active embedded chips into high density electronic board

Directory of Open Access Journals (Sweden)

Monier-Vinard Eric

2013-01-01

Full Text Available The recent Printed Wiring Board embedding technology is an attractive packaging alternative that allows a very high degree of miniaturization by stacking multiple layers of embedded chips. This disruptive technology will further increase the thermal management challenges by concentrating heat dissipation at the heart of the organic substrate structure. In order to allow the electronic designer to early analyze the limits of the power dissipation, depending on the embedded chip location inside the board, as well as the thermal interactions with other buried chips or surface mounted electronic components, an analytical thermal modelling approach was established. The presented work describes the comparison of the analytical model results with the numerical models of various embedded chips configurations. The thermal behaviour predictions of the analytical model, found to be within ±10% of relative error, demonstrate its relevance for modelling high density electronic board. Besides the approach promotes a practical solution to study the potential gain to conduct a part of heat flow from the components towards a set of localized cooled board pads.

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.

The use of salinity contrast for density difference compensation to improve the thermal recovery efficiency in high-temperature aquifer thermal energy storage systems

Science.gov (United States)

van Lopik, Jan H.; Hartog, Niels; Zaadnoordijk, Willem Jan

2016-08-01

The efficiency of heat recovery in high-temperature (>60 °C) aquifer thermal energy storage (HT-ATES) systems is limited due to the buoyancy of the injected hot water. This study investigates the potential to improve the efficiency through compensation of the density difference by increased salinity of the injected hot water for a single injection-recovery well scheme. The proposed method was tested through numerical modeling with SEAWATv4, considering seasonal HT-ATES with four consecutive injection-storage-recovery cycles. Recovery efficiencies for the consecutive cycles were investigated for six cases with three simulated scenarios: (a) regular HT-ATES, (b) HT-ATES with density difference compensation using saline water, and (c) theoretical regular HT-ATES without free thermal convection. For the reference case, in which 80 °C water was injected into a high-permeability aquifer, regular HT-ATES had an efficiency of 0.40 after four consecutive recovery cycles. The density difference compensation method resulted in an efficiency of 0.69, approximating the theoretical case (0.76). Sensitivity analysis showed that the net efficiency increase by using the density difference compensation method instead of regular HT-ATES is greater for higher aquifer hydraulic conductivity, larger temperature difference between injection water and ambient groundwater, smaller injection volume, and larger aquifer thickness. This means that density difference compensation allows the application of HT-ATES in thicker, more permeable aquifers and with larger temperatures than would be considered for regular HT-ATES systems.

A comparative study of high-viscosity cement percutaneous vertebroplasty vs. low-viscosity cement percutaneous kyphoplasty for treatment of osteoporotic vertebral compression fractures.

Science.gov (United States)

Sun, Kai; Liu, Yang; Peng, Hao; Tan, Jun-Feng; Zhang, Mi; Zheng, Xian-Nian; Chen, Fang-Zhou; Li, Ming-Hui

2016-06-01

The clinical effects of two different methods-high-viscosity cement percutaneous vertebroplasty (PVP) and low-viscosity cement percutaneous kyphoplasty (PKP) in the treatment of osteoporotic vertebral compression fractures (OVCFs) were investigated. From June 2010 to August 2013, 98 cases of OVCFs were included in our study. Forty-six patients underwent high-viscosity PVP and 52 patients underwent low-viscosity PKP. The occurrence of cement leakage was observed. Pain relief and functional activity were evaluated using the Visual Analog Scale (VAS) and Oswestry Disability Index (ODI), respectively. Restoration of the vertebral body height and angle of kyphosis were assessed by comparing preoperative and postoperative measurements of the anterior heights, middle heights and the kyphotic angle of the fractured vertebra. Nine out of the 54 vertebra bodies and 11 out of the 60 vertebra bodies were observed to have cement leakage in the high-viscosity PVP and low-viscosity PKP groups, respectively. The rate of cement leakage, correction of anterior vertebral height and kyphotic angles showed no significant differences between the two groups (P>0.05). Low-viscosity PKP had significant advantage in terms of the restoration of middle vertebral height as compared with the high-viscosity PVP (Pviscosity PVP and low-viscosity PKP have similar clinical effects in terms of the rate of cement leakage, restoration of the anterior vertebral body height, changes of kyphotic angles, functional activity, and pain relief. Low-viscosity PKP is better than high-viscosity PVP in restoring the height of the middle vertebra.

Resonance parallel viscosity in the banana regime in poloidally rotating tokamak plasmas

International Nuclear Information System (INIS)

Shaing, K.C.; Hsu, C.T.; Dominguez, N.

1994-01-01

Parallel viscosity in the banana regime in a poloidally (ExB) rotating tokamak plasma is calculated to include the effects of orbit squeezing and to allow the poloidal ExB Mach number M p to have a value of order unity. Here, E is the electric field and B is the magnetic field. The effects of orbit squeezing not only modify the size of the particle orbit, but also change the fraction of poloidally trapped particles. Resonance between the particle parallel (to B) speed u and the poloidal component of the ExB velocity can only occur for those particles with energy (v/v t ) 2 >M 2 p (with v the particle speed and v t the thermal speed). Thus, the resonance parallel plasma viscosity in the banana regime decreases exponentially with M 2 p when M 2 p ≥1, and has a local maximum of M 2 p ∼1

Viscosity of iodinated contrast agents during renal excretion

International Nuclear Information System (INIS)

Jost, Gregor; Lengsfeld, Philipp; Lenhard, Diana C.; Pietsch, Hubertus; Huetter, Joachim; Sieber, Martin A.

2011-01-01

Objective: Modern iodinated non-ionic contrast agents (CAs) can be classified based on their molecular structure into monomeric and dimeric CAs and have at comparable iodine concentrations a different viscosity and osmolality. During their renal excretion, CAs are concentrated in the renal tubuli which might enhance the viscosity difference between monomeric and dimeric CAs. The viscosity of a CA might have an underestimated importance for renal safety, as suggested by recent publications. In this study, we investigated the viscosities of CAs at the concentrations expected to be present in renal tubules. This concentration process was simulated in vitro using dialysis. Furthermore, we investigated urine viscosity and urine flow in rodents after administration of several non-ionic monomeric and dimeric CAs. Materials and methods: To estimate the viscosity of the CAs in vivo, we performed an in vitro dialysis of monomeric and dimeric CAs at various physiological osmolalities of the renal tubulus (290, 400, 500, 700 and 1000 mOsm/kg H 2 O). Following the dialysis, the iodine concentrations and the viscosities of the CAs were determined. Furthermore, to investigate the concentration process in vivo, we measured the urine viscosity and the urine flow in Han Wister rats after the administration of Iopromide, Iohexol, Ioversol, Iomeprol, Iodixanol, and Iosimenol at comparable iodine concentrations. As a control, saline was injected at the same volume. Results: In vitro dialysis of the dimeric CA increased the iodine concentration and strongly increased the viscosity at all tested osmolalities. In contrast, for the monomeric agents an increase in concentration and viscosity was observed only at 700 as well 1000 mOsm/kg H 2 O but to a lesser extent. In summary, dialysis strongly enhanced the viscosity differences between the non-ionic monomeric and dimeric CAs. The administration of dimeric CAs leads to a strong increase in urine viscosity; this was not observed for the

Viscosity of iodinated contrast agents during renal excretion

Energy Technology Data Exchange (ETDEWEB)

Jost, Gregor, E-mail: Gregor.Jost@bayer.com [TRG Diagnostic Imaging, Bayer Schering Pharma AG, Berlin (Germany); Lengsfeld, Philipp, E-mail: Philipp.Lengsfeld@bayer.com [Global Medical Affairs Diagnostic Imaging, Bayer Schering Pharma AG, Berlin (Germany); Lenhard, Diana C., E-mail: Diana.Lenhard@bayer.com [TRG Diagnostic Imaging, Bayer Schering Pharma AG, Berlin (Germany); Pietsch, Hubertus, E-mail: Hubertus.Pietsch@bayer.com [TRG Diagnostic Imaging, Bayer Schering Pharma AG, Berlin (Germany); Huetter, Joachim, E-mail: Joachim.Huetter@bayer.com [TRG Diagnostic Imaging, Bayer Schering Pharma AG, Berlin (Germany); Sieber, Martin A., E-mail: Martin.Sieber@bayer.com [TRG Diagnostic Imaging, Bayer Schering Pharma AG, Berlin (Germany)

2011-11-15

Objective: Modern iodinated non-ionic contrast agents (CAs) can be classified based on their molecular structure into monomeric and dimeric CAs and have at comparable iodine concentrations a different viscosity and osmolality. During their renal excretion, CAs are concentrated in the renal tubuli which might enhance the viscosity difference between monomeric and dimeric CAs. The viscosity of a CA might have an underestimated importance for renal safety, as suggested by recent publications. In this study, we investigated the viscosities of CAs at the concentrations expected to be present in renal tubules. This concentration process was simulated in vitro using dialysis. Furthermore, we investigated urine viscosity and urine flow in rodents after administration of several non-ionic monomeric and dimeric CAs. Materials and methods: To estimate the viscosity of the CAs in vivo, we performed an in vitro dialysis of monomeric and dimeric CAs at various physiological osmolalities of the renal tubulus (290, 400, 500, 700 and 1000 mOsm/kg H{sub 2}O). Following the dialysis, the iodine concentrations and the viscosities of the CAs were determined. Furthermore, to investigate the concentration process in vivo, we measured the urine viscosity and the urine flow in Han Wister rats after the administration of Iopromide, Iohexol, Ioversol, Iomeprol, Iodixanol, and Iosimenol at comparable iodine concentrations. As a control, saline was injected at the same volume. Results: In vitro dialysis of the dimeric CA increased the iodine concentration and strongly increased the viscosity at all tested osmolalities. In contrast, for the monomeric agents an increase in concentration and viscosity was observed only at 700 as well 1000 mOsm/kg H{sub 2}O but to a lesser extent. In summary, dialysis strongly enhanced the viscosity differences between the non-ionic monomeric and dimeric CAs. The administration of dimeric CAs leads to a strong increase in urine viscosity; this was not observed for

Thermal characteristics and performance of Ag-water nanofluid: Application to natural circulation loops

International Nuclear Information System (INIS)

Koca, Halil Dogacan; Doganay, Serkan; Turgut, Alpaslan

2017-01-01

Highlights: • Thermal conductivity and viscosity of Ag-water nanofluid were measured. • Thermal performance of Ag-water nanofluid was compared with water. • Effectiveness enhanced up to 11% with 1 wt% Ag-water nanofluid. • Effectiveness of Ag-water nanofluid samples increased with inclination angle. • Ag-water nanofluid has potential to be used in flat-plate solar collectors. - Abstract: The goal of this study is to investigate the thermal conductivity, viscosity and thermal performance in a single-phase natural circulation mini loop of Ag-water nanofluid which can be a potential working fluid for natural convective flat-plate solar collectors. The silver-water nanofluid with 5 wt% concentration, which contains also polyvinylpyrrolidone (PVP) with 1.25 wt%, was purchased. Then, the sample was diluted with de-ionized water to four different concentrations of 0.25, 0.5, 0.75 and 1 wt%. Thermal conductivity and viscosity were measured by 3ω method and Brookfield rheometer, respectively. An effectiveness factor was used to define the thermal performance of Ag-water nanofluids for different inclination angles and heating powers. The results showed that nanofluid samples are thermally less conductive than the literature, at ambient temperature (23 °C). The viscosity of nanofluid decreases significantly with increasing temperature and increases with increasing concentration. Our measurements appear to be more compatible with PVP solution results available in the literature. Effectiveness is enhanced up to 11% with 1 wt% concentrated nanofluid compared to de-ionized water and the effectiveness of the mini loop indicates an enhancement with increase in inclination angle and particle concentration at whole applied power. According to obtained results, it is concluded that Ag-water nanofluid has a promising potential to be used in natural convective flat-plate solar collector.

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....... The experiments show a significant increase in extensional viscosity with increasing pressure....

Early Thermal History of Rhea: The Role of Serpentinization and Liquid State Convection

OpenAIRE

Czechowski Leszek; Łosiak Anna

2016-01-01

Early thermal history of Rhea is investigated. The role of the following parameters of the model is investigated: time of beginning of accretion, tini, duration of accretion, tac, viscosity of ice close to the melting point, η0, activation energy in the formula for viscosity, E, thermal conductivity of silicate component, ksil, ammonia content, XNH3, and energy of serpentinization, cserp. We found that tini and tac are crucial for evolution. All other parameters are also important, but no dra...

Bulk viscosity in holographic Lifshitz hydrodynamics

International Nuclear Information System (INIS)

Hoyos, Carlos; Kim, Bom Soo; Oz, Yaron

2014-01-01

We compute the bulk viscosity in holographic models dual to theories with Lifshitz scaling and/or hyperscaling violation, using a generalization of the bulk viscosity formula derived in arXiv:1103.1657 from the null focusing equation. We find that only a class of models with massive vector fields are truly Lifshitz scale invariant, and have a vanishing bulk viscosity. For other holographic models with scalars and/or massless vector fields we find a universal formula in terms of the dynamical exponent and the hyperscaling violation exponent

Viscosity measurement techniques in Dissipative Particle Dynamics

Science.gov (United States)

Boromand, Arman; Jamali, Safa; Maia, Joao M.

2015-11-01

In this study two main groups of viscosity measurement techniques are used to measure the viscosity of a simple fluid using Dissipative Particle Dynamics, DPD. In the first method, a microscopic definition of the pressure tensor is used in equilibrium and out of equilibrium to measure the zero-shear viscosity and shear viscosity, respectively. In the second method, a periodic Poiseuille flow and start-up transient shear flow is used and the shear viscosity is obtained from the velocity profiles by a numerical fitting procedure. Using the standard Lees-Edward boundary condition for DPD will result in incorrect velocity profiles at high values of the dissipative parameter. Although this issue was partially addressed in Chatterjee (2007), in this work we present further modifications (Lagrangian approach) to the original LE boundary condition (Eulerian approach) that will fix the deviation from the desired shear rate at high values of the dissipative parameter and decrease the noise to signal ratios in stress measurement while increases the accessible low shear rate window. Also, the thermostat effect of the dissipative and random forces is coupled to the dynamic response of the system and affects the transport properties like the viscosity and diffusion coefficient. We investigated thoroughly the dependency of viscosity measured by both Eulerian and Lagrangian methodologies, as well as numerical fitting procedures and found that all the methods are in quantitative agreement.

Acquisition of an Advanced Thermal Analysis andImaging System for Integration with Interdisciplinary Researchand Education in Low Density Organic Inorganic Materials

Science.gov (United States)

2017-12-02

Report: Acquisition of an Advanced Thermal Analysis and Imaging System for Integration with Interdisciplinary Research and Education in Low Density...Agreement Number: W911NF-16-1-0475 Organization: University of Texas at El Paso Title: Acquisition of an Advanced Thermal Analysis and Imaging System ...for Integration with Interdisciplinary Research and Education in Low Density Organic-Inorganic Materials Report Term: 0-Other Email: dmisra2

Viscosity properties of sodium borophosphate glasses

International Nuclear Information System (INIS)

Gaylord, S.; Tincher, B.; Petit, L.; Richardson, K.

2009-01-01

The viscosity behavior of (1 - x)NaPO 3 -xNa 2 B 4 O 7 glasses (x = 0.05-0.20) have been measured as a function of temperature using beam-bending and parallel-plate viscometry. The viscosity was found to shift to higher temperatures with increasing sodium borate content. The kinetic fragility parameter, m, estimated from the viscosity curve, decreases from 52 to 33 when x increases from 0.05 to 0.20 indicating that the glass network transforms from fragile to strong with the addition of Na 2 B 4 O 7 . The decrease in fragility with increasing x is due to the progressive depolymerization of the phosphate network by the preferred four-coordinated boron atoms present in the low alkali borate glasses. As confirmed by Raman spectroscopy increasing alkali borate leads to enhanced B-O-P linkages realized with the accompanying transition from solely four-coordinated boron (in BO 4 units) to mixed BO 4 /BO 3 structures. The glass viscosity characteristics of the investigated glasses were compared to those of P-SF67 and N-FK5 commercial glasses from SCHOTT. We showed that the dependence of the viscosity of P-SF67 was similar to the investigated glasses due to similar phosphate network organization confirmed by Raman spectroscopy, whereas N-FK5 exhibited a very different viscosity curve and fragility parameter due to its highly coordinated silicate network

Accurate ab initio potential for the krypton dimer and transport properties of the low-density krypton gas.

Science.gov (United States)

Waldrop, Jonathan M; Song, Bo; Patkowski, Konrad; Wang, Xiaopo

2015-05-28

A new highly accurate potential energy curve for the krypton dimer was constructed using coupled-cluster calculations up to the singles, doubles, triples, and perturbative quadruples level, including corrections for core-core and core-valence correlation and for relativistic effects. The ab initio data points were fitted to an analytic potential which was used to compute the most important transport properties of the krypton gas. The viscosity, thermal conductivity, self-diffusion coefficient, and thermal diffusion factor were calculated by the kinetic theory at low density and temperatures from 116 to 5000 K. The comparisons with literature experimental data as well as with values from other pair potentials indicate that our new potential is superior to all previous ones. The transport property values computed in this work are recommended as standard values over the complete temperature range.

Bulk viscosity of strongly interacting matter in the relaxation time approximation

Science.gov (United States)

Czajka, Alina; Hauksson, Sigtryggur; Shen, Chun; Jeon, Sangyong; Gale, Charles

2018-04-01

We show how thermal mean field effects can be incorporated consistently in the hydrodynamical modeling of heavy-ion collisions. The nonequilibrium correction to the distribution function resulting from a temperature-dependent mass is obtained in a procedure which automatically satisfies the Landau matching condition and is thermodynamically consistent. The physics of the bulk viscosity is studied here for Boltzmann and Bose-Einstein gases within the Chapman-Enskog and 14-moment approaches in the relaxation time approximation. Constant and temperature-dependent masses are considered in turn. It is shown that, in the small mass limit, both methods lead to the same value of the ratio of the bulk viscosity to its relaxation time. The inclusion of a temperature-dependent mass leads to the emergence of the βλ function in that ratio, and it is of the expected parametric form for the Boltzmann gas, while for the Bose-Einstein case it is affected by the infrared cutoff. This suggests that the relaxation time approximation may be too crude to obtain a reliable form of ζ /τR for gases obeying Bose-Einstein statistics.

Shear viscosity and out of equilibrium dynamics

International Nuclear Information System (INIS)

El, Andrej; Xu Zhe; Greiner, Carsten; Muronga, Azwinndini

2009-01-01

Using Grad's method, we calculate the entropy production and derive a formula for the second-order shear viscosity coefficient in a one-dimensionally expanding particle system, which can also be considered out of chemical equilibrium. For a one-dimensional expansion of gluon matter with Bjorken boost invariance, the shear tensor and the shear viscosity to entropy density ratio η/s are numerically calculated by an iterative and self-consistent prescription within the second-order Israel-Stewart hydrodynamics and by a microscopic parton cascade transport theory. Compared with η/s obtained using the Navier-Stokes approximation, the present result is about 20% larger at a QCD coupling α s ∼0.3 (with η/s≅0.18) and is a factor of 2-3 larger at a small coupling α s ∼0.01. We demonstrate an agreement between the viscous hydrodynamic calculations and the microscopic transport results on η/s, except when employing a small α s . On the other hand, we demonstrate that for such small α s , the gluon system is far from kinetic and chemical equilibrium, which indicates the break down of second-order hydrodynamics because of the strong nonequilibrium evolution. In addition, for large α s (0.3-0.6), the Israel-Stewart hydrodynamics formally breaks down at large momentum p T > or approx. 3 GeV but is still a reasonably good approximation.

Analysis of aluminum base-reaction effect in density, porosity, and thermal insulation of porous fire bricks