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Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

Viscosity of Quantum Hall Fluids  

Science Journals Connector (OSTI)

The viscosity of quantum fluids with an energy gap at zero temperature is related to the adiabatic curvature on the space parametrizing flat background metrics. For quantum Hall fluids on two-dimensional tori, the quantum viscosity is computed. It turns out to be isotropic, constant, and proportional to the magnetic field strength.

J. E. Avron; R. Seiler; P. G. Zograf

1995-07-24T23:59:59.000Z

2

Reduced viscosity  

Science Journals Connector (OSTI)

n. (1) (IUPAC: viscosity number) Reduced viscosity is the fluid viscosity increase per unit of polymer solute concentration.... where ? ...

2007-01-01T23:59:59.000Z

3

Viscosity of a nucleonic fluid  

E-Print Network [OSTI]

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

Aram Z. Mekjian

2012-03-21T23:59:59.000Z

4

Viscosity of High Energy Nuclear Fluids  

E-Print Network [OSTI]

Relativistic high energy heavy ion collision cross sections have been interpreted in terms of almost ideal liquid droplets of nuclear matter. The experimental low viscosity of these nuclear fluids have been of considerable recent quantum chromodynamic interest. The viscosity is here discussed in terms of the string fragmentation models wherein the temperature dependence of the nuclear fluid viscosity obeys the Vogel-Fulcher-Tammann law.

V. Parihar; A. Widom; D. Drosdoff; Y. N. Srivastava

2007-03-15T23:59:59.000Z

5

Viscosity of a one-component polarizable fluid  

Science Journals Connector (OSTI)

The viscosity of a one-component polarizable fluid in an electric field is studied by computer simulations. The fluid viscosity increases with the field through three stages. In a weak field, the fluid remains Newtonian, although its viscosity increases. At this stage, while drifting in the flow direction, particles diffuse in the direction perpendicular to the flow. In an intermediate electric field, the fluid has tilted and broken chains moving with the flow and the fluid becomes non-Newtonian. The viscosity ? and the shear rate ?? have the relationship ?=?0e-???, where ? is the relaxation time and ?0 is exponentially proportional to the dipolar interaction energy and the volume fraction. In a strong electric field, the fluid contains condensed chains that provide yield stress and hysteresis.

J. M. Sun and R. Tao

1995-07-01T23:59:59.000Z

6

Viscosity  

Science Journals Connector (OSTI)

Viscosity is a measure of the resistance of ... forces that act within a moving fluid. Viscosity can also be defined as the ratio...

2008-01-01T23:59:59.000Z

7

Quartz resonator fluid density and viscosity monitor  

DOE Patents [OSTI]

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

Martin, Stephen J. (Albuquerque, NM); Wiczer, James J. (Albuquerque, NM); Cernosek, Richard W. (Albuquerque, NM); Frye, Gregory C. (Cedar Crest, NM); Gebert, Charles T. (Albuquerque, NM); Casaus, Leonard (Bernalillo, NM); Mitchell, Mary A. (Tijeras, NM)

1998-01-01T23:59:59.000Z

8

Viscosity of Quantum Hall Fluids J. E. Avron  

E-Print Network [OSTI]

Viscosity of Quantum Hall Fluids J. E. Avron Department of Physics, Technion, 32000 Haifa, Israel R April 25, 1997 Abstract The viscosity of quantum fluids with an energy gap at zero temperature is non of the parameter space). For a quantum Hall fluid on two dimensional tori this viscosity is computed. In this case

9

46.1 Shear Viscosity An important mechanical property of fluids is viscosity. Physical systems and applications as diverse as  

E-Print Network [OSTI]

46-1 46.1 Shear Viscosity An important mechanical property of fluids is viscosity. Physical systems involve fluid flow and are controlled to some degree by fluid viscosity. Viscosity is the tendency, viscosity is related to molecular dif- fusion and depends on the interactions between molecules or

Kostic, Milivoje M.

10

Viscosity of isotropic hard particle fluids  

Science Journals Connector (OSTI)

A kinetic theory for the frequency?dependent shear viscosity ?(?) of isotropic fluids composed of non?spherical hard convex bodies is extended in two ways. First the theory is reformulated to allow ?(?) to be expressed directly in terms of matrix elements involving the shear stress tensor rather than in terms of the transverse momentum correlation function. Second relaxation of the antisymmetric component of the stress due to coupling with spin angular momentum is explicitly incorporated; this corrects an error in a previous version of the theory. The revised kinetic theory is compared with computer simulations for hard ellipsoids of revolution of axial ratio 2 3 5 and 10. Both the symmetric and antisymmetric contributions to ?(?) are well reproduced. Coupling with the collective molecular second?rank orientation tensor remains an important factor in determining the variation of ?(?) from high to low frequencies; the prediction of the magnitude of the associated dip in ?(?) is significantly improved. The new version of the theory is also more successful in predicting values of the zero?frequency shear viscosity ? the shear?orientation coupling parameter R and the Stokes–Einstein (–Debye) products D s? and D r?.

Michael P. Allen; Philip J. Camp; Carl P. Mason; Glenn T. Evans; Andrew J. Masters

1996-01-01T23:59:59.000Z

11

Viscosity and Density of Reference Fluid.  

E-Print Network [OSTI]

??The viscosity and density of bis(8-methylnonyl) benzene-1,2- dicarboxylate {diisodecyl phthalate (DIDP)}, with a nominal viscosity at T = 298 K and p = 0.1 MPa… (more)

Almotari, Masaed Moti M

2006-01-01T23:59:59.000Z

12

Viscosity of an ideal relativistic quantum fluid: A perturbative study  

E-Print Network [OSTI]

We show that a quantized ideal fluid will generally exhibit a small but non-zero viscosity due to the backreaction of quantum soundwaves on the background. We use an effective field theory expansion to estimate this viscosity to first order in perturbation theory. We discuss our results, and whether this estimate can be used to obtain a more model-independent estimate of the "quantum bound" on the viscosity of physical systems

Giorgio Torrieri

2011-12-17T23:59:59.000Z

13

Non-invasive fluid density and viscosity measurement  

SciTech Connect (OSTI)

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

Sinha, Dipen N. (Los Alamos, NM)

2012-05-01T23:59:59.000Z

14

Viscosity, entropy and the viscosity to entropy density ratio; how perfect is a nucleonic fluid?  

E-Print Network [OSTI]

The viscosity of hadronic matter is studied using a classical evaluation of the scattering angle and a quantum mechanical discussion based on phase shifts from a potential. Semi classical limits of the quantum theory are presented. A hard sphere and an attractive square well potential step are each considered as well as the combined effects of both. The lowest classical value of the viscosity for an attractive potential is shown to be a hard sphere limit. The high wave number-short wavelength limits of the quantum result have scaling laws associated with it for both the viscosity and entropy. These scaling laws are similar to the Fraunhoher diffraction increase for the hard sphere geometric cross section. Specific examples for nuclear collisions are given. The importance of the nuclear tensor force and hard core is mentioned. The viscosity (eta), entropy density (s) and eta/s ratio are calculated for a gas of dilute neutrons in the unitary limit of large scattering length. Away from the unitary limit, the ratio of the interaction radius or the scattering length to the interparticle spacing introduces a variable y besides the fugacity z. The isothermal compressibility is shown to impose important constraints. The results for eta/s are compared to the AdS/CFT string theory minimum of (1/4Pi)hbar/kb to see how close a nucleonic gas is to being a perfect fluid. The eta/s ~1hbar/kb for a neutron gas in its unitary limit. The eta/s 3hbar/kb treating the nuclear scattering as billiard ball collisions. The minimum eta/s for a neutron gas occurs in regions of negative isothermal compressibility and high fugacity where higher virial terms are important. In a neutron-proton system higher virial terms are associated with a liquid-gas phase transition and critical opalescent phenomena.The type of flow-laminar,vortex, turbulent- is investigated.

Aram Z. Mekjian

2010-09-29T23:59:59.000Z

15

Sonically produced heat in a fluid with bulk viscosity and shear viscosity  

Science Journals Connector (OSTI)

In a viscous fluid sound produces heat in a spatial pattern which in general depends on the relative magnitudes of the shear viscosity coefficient ? and the bulk viscosity coefficient B’. It is well known that when the particle velocity components u i relative to Cartesian coordinates x i are given for an arbitrary sound field or any field of flow the volume rate of heat production q v can be determined from a dissipation function in the form B’T 1+?T 2. Here T 1 and T 2 are quadratic functions involving derivatives of the type ?u i /?x j . In this paper examples are discussed for continuous monofrequency sound fields including crossed plane waves as well as focused and unfocused fields. In these examples spatial distributions of the time?averaged quantity ?q v ? for media in which the loss mechanism is primarily bulk viscosity are compared to those for media in which shear viscosity dominates.

Wesley L. Nyborg

1986-01-01T23:59:59.000Z

16

Textured-surface quartz resonator fluid density and viscosity monitor  

DOE Patents [OSTI]

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

Martin, Stephen J. (Albuquerque, NM); Wiczer, James J. (Albuquerque, NM); Cernosek, Richard W. (Albuquerque, NM); Frye, Gregory C. (Cedar Crest, NM); Gebert, Charles T. (Albuquerque, NM); Casaus, Leonard (Bernalillo, NM); Mitchell, Mary A. (Tijeras, NM)

1998-08-25T23:59:59.000Z

17

Determination of fluid viscosities from biconical annular geometries: Experimental and modeling studies  

E-Print Network [OSTI]

to measure the viscosity of a fluid at downhole conditions. The design investigated in this study addresses several limitations encountered in previous designs. The prototype was calibrated and tested with fluids with viscosities ranging from 1 to 28 cp under...

Rondon, Nolys Javier

2009-05-15T23:59:59.000Z

18

Kinematic Viscosity  

Science Journals Connector (OSTI)

In classical fluid mechanics, kinematic viscosity equals the dynamic viscosity divided by the density of the material...2 s-1].

2014-01-01T23:59:59.000Z

19

Department of Mechanical Engineering Fall 2010 Viscosity Measurement of Troublesome Fluids  

E-Print Network [OSTI]

Fluids Overview Air Products completes many batches of a variety of different fluids every year takes Air Products 2-3 hours to obtain a viscosity measurement. The goal of this project is to design a process that will shorten the time it takes Air Products to obtain a viscosity measurement, without

Demirel, Melik C.

20

Viscosity  

Science Journals Connector (OSTI)

Quantitatively, a measure of this property, defined as the shear stress divided by the rate of shear in steady simple-shear flow. Often used synonymously with apparent viscosity [Pa.s.].

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

viscosity  

Science Journals Connector (OSTI)

...any internal resistance of substance to deformation or relative motion within itself, when it is subjected to shear stress by a liquid or gas. The ratio is called coefficient of viscosity, in units of poise. A...

2009-01-01T23:59:59.000Z

22

Micromechanical transient sensor for measuring viscosity and density of a fluid  

DOE Patents [OSTI]

A method and apparatus for measuring the viscosity and/or specific density of a fluid utilizes a microcantilever vibrated in the analyte fluid. The source of vibration is switched on and off and the transient behavior or decay in amplitude of the vibration is monitored. The method is particularly useful for the measurement of process conditions in remote locations in real time.

Thundat, Thomas G. (Knoxville, TN); Oden, Patrick I. (Plano, TX); Warmack, Robert J. (Knoxville, TN); Finot, Eric Laurent (Torcy, FR)

2001-01-01T23:59:59.000Z

23

Effect of viscosity and shear flow on the nonlinear two fluid interfacial structures  

SciTech Connect (OSTI)

A nonlinear formulation is presented to deal with the combined action of Rayleigh-Taylor and Kelvin-Helmholtz instabilities as well as combined Ricthmyer-Meshkov and Kelvin-Helmholtz instabilities at the two fluid interface under the influence of viscosity and consequent shear flow. Using Layzer's model, the development of the interfacial structures like bubbles is investigated analytically and numerically. It is found that the growth and normal velocity of the structures are dependent on the relative velocity shear and the kinematic coefficient of viscosity of both the fluids. Both the bubble growth and growth rate are reduced significantly for fluids of higher viscosity coefficient with small velocity shear difference. It is also observed that, for viscous fluids, the transverse velocity of the perturbed interface becomes slower under certain conditions.

Banerjee, Rahul [Department of Instrumentation Science and Centre for Plasma Studies, Jadavpur University, Kolkata 700032 (India); St Paul's Cathedral Mission College, 33/1, Raja Rammohan Roy Sarani, Kolkata 700009 (India); Mandal, Labakanta; Khan, M.; Gupta, M. R. [Department of Instrumentation Science and Centre for Plasma Studies, Jadavpur University, Kolkata 700032 (India)

2012-12-15T23:59:59.000Z

24

Computer simulation of effective viscosity of fluid-proppant mixture used in hydraulic fracturing  

E-Print Network [OSTI]

The paper presents results of numerical experiments performed to evaluate the effective viscosity of a fluid-proppant mixture, used in hydraulic fracturing. The results, obtained by two complimenting methods (the particle dynamics and the smoothed particle hydrodynamics), coincide to the accuracy of standard deviation. They provide an analytical equation for the dependence of effective viscosity on the proppant concentration, needed for numerical simulation of the hydraulic fracture propagation.

Kuzkin, Vitaly A; Linkov, Aleksandr M

2013-01-01T23:59:59.000Z

25

Viscosity-Induced Crossing of the Phantom Divide in the Dark Cosmic Fluid  

E-Print Network [OSTI]

Choosing various natural forms for the equation-of-state parameter w and the bulk viscosity \\zeta, we discuss how it is possible for a dark energy fluid to slide from the quintessence region across the divide w=-1 into the phantom region, and thus into a Big Rip future singularity. Different analytic forms for \\zeta, as powers of the scalar expansion, are suggested and compared with experiments.

Iver Brevik

2013-12-11T23:59:59.000Z

26

Specific Viscosity  

Science Journals Connector (OSTI)

n Equal to the relative viscosity of the same solution minus one. It represents the increase in viscosity that may be contributed by the polymeric solute. The specific viscosity, ?sp is defined by th...

Jan W. Gooch

2011-01-01T23:59:59.000Z

27

Effect of viscosity and surface tension on the growth of Rayleigh -Taylor instability and Richtmyer-Meshkov instability induced two fluid inter-facial nonlinear structure  

E-Print Network [OSTI]

The effect of viscous drag and surface tension on the nonlinear two fluid inter facial structures induced by Rayleigh -Taylor instability and Richtmyer-Meshkov instability are investigated.Viscosity and surface tension play important roles on the fluid instabilities. It is seen that the magnitude of the suppression of the terminal growth rate of the tip of the bubble height depends only on the viscous coefficient of the upper (denser) fluid through which the bubble rises and surface tension of the interface. But in regard to spike it is shown that in an inviscid fluid spike does not remain terminal but approaches a free fall as the Atwood number A increases. In this respect there exits qualitative agreement with simulation result as also with some earlier theoretical results. Viscosity reduces the free fall velocity appreciably and with increasing viscosity tends to make it terminal. Results obtained from numerical integration of the relevant nonlinear equations describing the temporal development of the spike support the foregoing observations.

M. R. Gupta; Rahul Banerjee; L. K. Mandal; R. Bhar; H. C. Pant; Manoranjan Khan; M. K. Srivastava

2011-06-07T23:59:59.000Z

28

Kinematic Viscosity  

Science Journals Connector (OSTI)

n (kinetic viscosity) The absolute (dynamic) viscosity of a fluid divided by the density...2/s, but the cgs unit, the stoke, which equals 10?4 m2/s, is still in wide use, as is its submultiple, the c...

Jan W. Gooch

2011-01-01T23:59:59.000Z

29

Density measurements Viscosity measurements  

E-Print Network [OSTI]

Density measurements Viscosity measurements Temperature measurements Pressure measurements Flow rate measurements Velocity measurements Sensors How to measure fluid flow properties ? Am´elie Danlos Ravelet Experimental methods for fluid flows: an introduction #12;Density measurements Viscosity

Ravelet, Florent

30

Enhanced remedial amendment delivery through fluid viscosity modifications: Experiments and numerical simulations  

Science Journals Connector (OSTI)

Low-permeability zones are typically bypassed when remedial fluids are injected into subsurface heterogeneous aquifer systems. Therefore, contaminants in the bypassed areas may not be contacted by the amendments in the remedial fluid, which may significantly prolong remediation operations. Laboratory experiments and numerical studies have been conducted to investigate the use of a shear-thinning polymer (Xanthan gum) to improve access to low-permeability zones in heterogeneous systems. The chemicals sodium mono-phosphate and the surfactant MA-80 were used as the remedial amendments. The impact of polymer concentration, fluid injection rate, and permeability contrast in the heterogeneous systems has been studied in a series of eleven two-dimensional flow cell experiments. The Subsurface Transport over Multiple Phases (STOMP) simulator was modified to include polymer-induced shear-thinning effects. The experimental and simulation results clearly show that using the polymer leads to an enhanced delivery of remedial amendments to lower-permeability zones and an increased sweeping efficiency. An added benefit of using the polymer is the stabilization of the displacing front when density differences exist between displaced and displacing fluids. The modified STOMP simulator was able to predict the experimental observed fluid displacing behavior well and might be used to predict subsurface remediation performance when a shear-thinning fluid is used to remediate a heterogeneous system at larger scales.

L. Zhong; M. Oostrom; T.W. Wietsma; M.A. Covert

2008-01-01T23:59:59.000Z

31

Elongational viscosity  

Science Journals Connector (OSTI)

(extensional viscosity, Trouton viscosity) n. The viscosity that characterizes an element undergoing elongational flow ... rate, unlike the usual reduction of shear viscosity with rate. Tensile viscosities are ap...

2007-01-01T23:59:59.000Z

32

On steady flows of fluids with pressure– and shear–dependent viscosities  

Science Journals Connector (OSTI)

...consider reflects the physics of the problem under consideration...shear-dependent viscosities 655 rate. We will provide a survey...follows. In order to pass to the limit in the proof...function of the shear rate. The following lemma...Bridgman, P. W. 1931 The physics of high pressure. Macmillan...

2005-01-01T23:59:59.000Z

33

Ionizing Electron Incidents as an Efficient Way to Reduce Viscosity of Heavy Petroleum Fluids  

E-Print Network [OSTI]

Qmin minimum energy loss in a single collision (eV) Qmax maximum energy loss in a single collision (eV) Qavg average energy loss in a single collision (eV) W (Q) Probability density ( 1eV) Macroscopic cross section ( 1m), viscosity of the uids (cp...

Alfi, Masoud

2012-10-19T23:59:59.000Z

34

Intrinsic Viscosity and Kinematic Viscosity  

Science Journals Connector (OSTI)

Intrinsic Viscosity and Kinematic Viscosity ... Hydrodynamic Characterization of Lupin Proteins: Solubility, Intrinsic Viscosity, and Molar Mass ... Hydrodynamic Characterization of Lupin Proteins: Solubility, Intrinsic Viscosity, and Molar Mass ...

Charles Tanford

1955-01-01T23:59:59.000Z

35

Viscosity races  

Science Journals Connector (OSTI)

Viscosity races ... A simple demonstration that illustrates the relationship between molecular size and viscosity. ...

William M. Hemmerlin; Kenton B. Abel

1991-01-01T23:59:59.000Z

36

New fluids help increase effectiveness of hydraulic fracturing  

SciTech Connect (OSTI)

It is important to choose the most effective fluid for hydraulic fracturing a particular formation. Fracturing fluids are used to initiate formation parting, extend the fracture into the reservoir, and to transport and distribute proppant. This paper discusses the fundamental of fluid types, viscosifiers, and fluid rheology.

Ebinger, C.D.; Hunt, E.

1989-06-05T23:59:59.000Z

37

Viscosity number  

Science Journals Connector (OSTI)

n. The IUPAC term for reduced viscosity. , where ? is the viscosity of the polymer solution; ? 0 is the viscosity of the pure s...

2007-01-01T23:59:59.000Z

38

Elongational Viscosity  

Science Journals Connector (OSTI)

n (extensional viscosity, Trouton viscosity) The viscosity that characterizes an element undergoing Elongational Flow ...(above). It is equal to the tensile ...

Jan W. Gooch

2011-01-01T23:59:59.000Z

39

Inherent viscosity  

Science Journals Connector (OSTI)

(logarithmic viscosity number) n. In measurement of dilute-solution viscosities, the inherent viscosity is the ratio of the natural logarithm of the relative viscosity to the concentration of the polymer in... ...

2007-01-01T23:59:59.000Z

40

Intrinsic viscosity  

Science Journals Connector (OSTI)

\\in-¦trin-zik-\\ (limiting viscosity number) n. In measurements of dilute-solution viscosity, intrinsic viscosity is the limit of the reduced and inherent viscosities as the concentration of polymer solute approac...

2007-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Inherent Viscosity  

Science Journals Connector (OSTI)

n (logarithmic viscosity number) In measurement of dilute-solution viscosities, the inherent viscosity is the ratio of the natural logarithm of the relative viscosity to the concentration of the poly...

Jan W. Gooch

2011-01-01T23:59:59.000Z

42

Viscosity in modified gravity  

E-Print Network [OSTI]

A bulk viscosity is introduced in the formalism of modified gravity. It is shown that, on the basis of a natural scaling law for the viscosity, a simple solution can be found for quantities such as the Hubble parameter and the energy density. These solutions may incorporate a viscosity-induced Big Rip singularity. By introducing a phase transition in the cosmic fluid, the future singularity can nevertheless in principle be avoided.

Iver Brevik

2012-11-12T23:59:59.000Z

43

Viscosity Measurements on Nitrogen  

Science Journals Connector (OSTI)

Viscosity Measurements on Nitrogen ... (15)?Clarke, A. G.; Smith, E. B. Low-temperature viscosities and intermolecular forces of simple gases. ... The coupling also serves as a frictionless bearing for a slender rotating cylindrical body which is slowed down due to the viscous drag of the fluid surrounding the cylinder. ...

Daniel Seibt; Eckhard Vogel; Eckard Bich; Daniel Buttig; Egon Hassel

2006-01-11T23:59:59.000Z

44

Zahn Viscosity Cup  

Science Journals Connector (OSTI)

n A one-shot devices for obtaining quick measurements in a roughly linear way, of the Kinematic Viscosity of the test liquid, typically a free-flowing fluid...

Jan W. Gooch

2011-01-01T23:59:59.000Z

45

Viscosity Problems in Igneous Rocks  

Science Journals Connector (OSTI)

The earth's magma a siliceous melt which is believed to underlie the entire solid crust of the earth is in all probability a highly viscous liquid. Wherever molten lava is observed in motion either in craters of volcanoes (Kilauea Mauna Loa Hawaii) or as disastrous flows which descend volcanic mountains (Vesuvius Mount Aetna etc.) or in the vicinity of volcanic fissures (Laki Eldgja rift Iceland) it behaves like a liquid of appreciable viscosity; the degree of viscosity however varies depending on the proportion of admixed gases and water vapor and the chemical composition of the lava. Lavas rich in silica are highly viscous (rhyolite dacite) while those rich in iron and magnesium (basalt andesite) are more fluid. The viscosity of every lava flow increases until the melt slowly freezes because of the chilling effect of the surface temperatures on the earth.

Robert Balk

1932-01-01T23:59:59.000Z

46

Influence of viscosity modifier nature and concentration on the viscous flow behaviour of oil-based drilling fluids at high pressure  

Science Journals Connector (OSTI)

Abstract This work deals with the effect of viscosity modifier nature and concentration on the rheological properties of model oil-based drilling fluids (OBM) submitted to high pressure. The oil-based fluids were formulated by dispersing, with a high shear mixer, two selected organobentonites in a mineral oil, at room temperature. The viscous flow behaviour of the corresponding dispersions was characterised as a function of pressure, organoclay nature and organoclay concentration, using a controlled-stress rheometer equipped with both pressure cell and coaxial cylinder geometries. A factorial Sisko–Barus model, which takes into account both shear and pressure effects in the same equation, fitted the experimental pressure–viscosity data fairly well. The influence of disperse phase concentration on the shear-thinning characteristics of these organoclay dispersions is related to the development of different microstructures, which depend on organoclay nature. In this sense, the resulting microstructure has been attributed to the cohesion energy between microgels domains. From the experimental results obtained, it can be concluded that the viscous flow behaviour of the OBM investigated is strongly affected by organoclay nature and concentration. The pressure–viscosity behaviour of these dispersions is mainly influenced by the piezoviscous properties of the oil and the properties of the continuous phase. The Sisko–Barus model proposed can be a useful tool, from an engineering point of view, for calculating pressure losses in the different sections of the bore, as well as being of significant help to solve other additional problems, such as hole cleaning, induced fracturing, and hole erosion during the drilling operation.

J. Hermoso; F. Martinez-Boza; C. Gallegos

2014-01-01T23:59:59.000Z

47

A mechanistic study explaining the synergistic viscosity increase obtained from polyethylene oxide (PEO) and {beta}-naphthalene sulfonate (BNS) in shotcrete  

SciTech Connect (OSTI)

In shotcrete, a combination of polyethylene oxide (PEO) and {beta}-naphthalene sulfonate (BNS) is commonly applied to reduce rebound. Here, the mechanism for the synergistic viscosity increase resulting from this admixture combination was investigated via x-ray diffraction (XRD), infrared and nuclear magnetic resonance (NMR) spectroscopy. It was found that the electron-rich aromatic rings present in BNS donate electrons to the alkyl protons of PEO and thus increase the electron density there. This rare interaction is known as CH-{pi} interaction and leads to the formation of a supramolecular structure whereby PEO chains bind weakly to BNS molecules. Through this mechanism a polymer network exhibiting exceptionally high molecular weight and thus viscosity is formed. Among polycondensates, sulfanilic acid-phenol-formaldehyde (SPF) provides even higher synergy with PEO than BNS while melamine (PMS), acetone (AFS) or polycarboxylate (PCE) based superplasticizers do not work at all. Effectiveness of lignosulfonates is dependent on their degree of sulfonation.

Pickelmann, J.; Plank, J., E-mail: sekretariat@bauchemie.ch.tum.de

2012-11-15T23:59:59.000Z

48

Viscosity index  

Science Journals Connector (OSTI)

(1929) n....An arbitrary number assigned as a measure of the constancy of the viscosity of a lubricating oil with change of temperature with higher numbers indicating viscosities that change little with temperatu...

2007-01-01T23:59:59.000Z

49

Initial viscosity  

Science Journals Connector (OSTI)

n....A term used in the vinyl plastisol industry to denote the viscosity measured immediately after the plastisol has been mixed. The viscosity normally rises at a declining rate after...

2007-01-01T23:59:59.000Z

50

Viscosity depressant  

Science Journals Connector (OSTI)

n....A substance that, when added in a relatively minor amount to a liquid, lowers its viscosity. Such materials, e.g., ethoxylated ... often incorporated in vinyl plastisols to lower their viscosities

2007-01-01T23:59:59.000Z

51

Initial Viscosity  

Science Journals Connector (OSTI)

n...A term used in the vinyl plastisol industry to denote the viscosity measured immediately after the plastisol has been mixed. The viscosity normally rises at a declining rate after...

Jan W. Gooch

2011-01-01T23:59:59.000Z

52

Hall viscosity from gauge/gravity duality  

E-Print Network [OSTI]

In (2+1)-dimensional systems with broken parity, there exists yet another transport coefficient, appearing at the same order as the shear viscosity in the hydrodynamic derivative expansion. In condensed matter physics, it is referred to as "Hall viscosity". We consider a simple holographic realization of a (2+1)-dimensional isotropic fluid with broken spatial parity. Using techniques of fluid/gravity correspondence, we uncover that the holographic fluid possesses a nonzero Hall viscosity, whose value only depends on the near-horizon region of the background. We also write down a Kubo's formula for the Hall viscosity. We confirm our results by directly computing the Hall viscosity using the formula.

Omid Saremi; Dam Thanh Son

2011-03-24T23:59:59.000Z

53

Amine-functionalized task-specific ionic liquids: a mechanistic explanation for the dramatic increase in viscosity upon complexation with CO{sub 2} from molecular simulation  

SciTech Connect (OSTI)

The capture of CO{sub 2} from fossil fuel combustion, particularly in coal-fired power plants, represents a critical component of efforts aimed at stabilizing greenhouse gas levels in the atmosphere. Recently, a series of second-generation task-specific ionic liquids (TSILs) containing amine functional groups have been synthesized and demonstrated to have much higher capacities for CO{sub 2} due to their reactivity with CO{sub 2}, as well unusually high viscosities in both the neat and complexed states. The current work extends the seminal studies of CO{sub 2} capture with ionic liquids (ILs) by providing insight from simulations into the mechanism responsible for the dramatic increase in viscosity upon complexation. Simulations conclusively demonstrate that the slow translational and rotational dynamics, which are manifest in the high viscosity, may be attributable to the formation of a strong, pervasive hydrogen-bonded network. Semiquantitative estimates of the cation and anion self-diffusion coefficients and rotational time constants, as well as detailed hydrogen bond analysis, are consistent with the experimentally observed formation of glassy or gel-like materials upon contact with CO{sub 2}. This has significant implications for the design of new approaches or materials involving ILs that take advantage of these preconceived limitations, in the synthesis or manipulation of new TSIL frameworks for CO{sub 2} capture, and in novel experimental studies of chemistries and dynamics in persistent heterogeneous environments.

Gutowski, K.E.; Maginn, E.J. [University of Notre Dame, Notre Dame, IN (United States)

2008-11-15T23:59:59.000Z

54

Viscosity of alumina nanoparticles dispersed in car engine coolant  

SciTech Connect (OSTI)

The present paper, describes our experimental results on the viscosity of the nanofluid prepared by dispersing alumina nanoparticles (<50 nm) in commercial car coolant. The nanofluid prepared with calculated amount of oleic acid (surfactant) was tested to be stable for more than 80 days. The viscosity of the nanofluids is measured both as a function of alumina volume fraction and temperature between 10 and 50 C. While the pure base fluid display Newtonian behavior over the measured temperature, it transforms to a non-Newtonian fluid with addition of a small amount of alumina nanoparticles. Our results show that viscosity of the nanofluid increases with increasing nanoparticle concentration and decreases with increase in temperature. Most of the frequently used classical models severely under predict the measured viscosity. Volume fraction dependence of the nanofluid viscosity, however, is predicted fairly well on the basis of a recently reported theoretical model for nanofluids that takes into account the effect of Brownian motion of nanoparticles in the nanofluid. The temperature dependence of the viscosity of engine coolant based alumina nanofluids obeys the empirical correlation of the type: log ({mu}{sub nf}) = A exp(BT), proposed earlier by Namburu et al. (author)

Kole, Madhusree; Dey, T.K. [Thermophysical Measurements Laboratory, Cryogenic Engineering Centre, Indian Institute of Technology, Kharagpur 721 302 (India)

2010-09-15T23:59:59.000Z

55

Viscosity of colloidal suspensions  

Science Journals Connector (OSTI)

Simple expressions are given for the Newtonian viscosity ?N(?) as well as the viscoelastic behavior of the viscosity ?(?,?) of neutral monodisperse hard-sphere colloidal suspensions as a function of volume fraction ? and frequency ? over the entire fluid range, i.e., for volume fractions 0viscosity as composed as the sum of two relevant physical processes: ?(?,?)=??(?)+?cd(?,?), where ??(?)=?0?(?) is the infinite frequency (or very short time) viscosity, with ?0 the solvent viscosity, ?(?) the equilibrium hard-sphere radial distribution function at contact, and ?cd(?,?) the contribution due to the diffusion of the colloidal particles out of cages formed by their neighbors, on the Péclet time scale ?P, the dominant physical process in concentrated colloidal suspensions. The Newtonian viscosity ?N(?)=?(?,?=0) agrees very well with the extensive experiments of van der Werff et al., [Phys. Rev. A 39, 795 (1989); J. Rheol. 33, 421 (1989)] and others. Also, the asymptotic behavior for large ? is of the form ??(?)+?0A(?)(??P)-1/2, in agreement with these experiments, but the theoretical coefficient A(?) differs by a constant factor 2/?(?) from the exact coefficient, computed from the Green-Kubo formula for ?(?,?). This still enables us to predict for practical purposes the viscoelastic behavior of monodisperse spherical colloidal suspensions for all volume fractions by a simple time rescaling.

R. Verberg; I. M. de Schepper; E. G. D. Cohen

1997-03-01T23:59:59.000Z

56

Viscosity of bacterial suspensions : hydrodynamic interactions and self-induced noise.  

SciTech Connect (OSTI)

The viscosity of a suspension of swimming bacteria is investigated analytically and numerically. We propose a simple model that allows for efficient computation for a large number of bacteria. Our calculations show that long-range hydrodynamic interactions, intrinsic to self-locomoting objects in a viscous fluid, result in a dramatic reduction of the effective viscosity. In agreement with experiments on suspensions of Bacillus subtilis, we show that the viscosity reduction is related to the onset of large-scale collective motion due to interactions between the swimmers. The simulations reveal that the viscosity reduction occurs only for relatively low concentrations of swimmers: Further increases of the concentration yield an increase of the viscosity. We derive an explicit asymptotic formula for the effective viscosity in terms of known physical parameters and show that hydrodynamic interactions are manifested as self-induced noise in the absence of any explicit stochasticity in the system.

Ryan, S. D.; Haines, B. M.; Berlyand, L. V.; Ziebert, F.; Aranson, I. S. (Materials Science Division); (Pennsylvania State Univ.); (UMR CNRS)

2011-05-01T23:59:59.000Z

57

Viscosity Measurement G.E. Leblanc  

E-Print Network [OSTI]

30 Viscosity Measurement G.E. Leblanc McMaster University R.A. Secco The University of Western Ontario 30.1 Shear Viscosity ............................................................. 30-l Newtonian and Non-Newtonian Fluids l Dimensions and Units of Viscosity l Viscometer Types l Capillary M. Kostic

Kostic, Milivoje M.

58

Viscosity measurements in dense microemulsions  

Science Journals Connector (OSTI)

We report the results of a measurement of the shear viscosity as a function of the temperature and of the water volume fraction in a three-component sodium di(2-ethylhexyl)sulfosuccinate-decane-water microemulsion. The explored concentration range is 0???0.73 and the packing fraction of the water-in-oil spherical droplets has been changed in order to obtain a very dense glass-forming liquid. Well-defined maxima in the relative viscosity have been observed at different concentrations and the corresponding temperature values decrease with increasing ?. The data are discussed considering the system as a colloidal one in which aggregation phenomena are present. In such a way, on the basis of a two-fluid model, we can consider two different contributions to the viscosity. One is directly connected to the repulsive interaction potential, while the second one is directly connected to the attractive interaction that contributes indirectly, through the formation of aggregates. The results are compatible with those previously obtained by light-scattering measurements that gives clear evidence of the presence of a large structural order at the glass transition.

D. Majolino; F. Mallamace; S. Venuto; N. Micali

1990-12-15T23:59:59.000Z

59

Melt Viscosity  

Science Journals Connector (OSTI)

n...The resistance to shear in a molten resin, quantified as the quotient of shear stress divided by shear rate at any point in the flowing material. Elongational viscosity, which comes into plan in ...

Jan W. Gooch

2011-01-01T23:59:59.000Z

60

Viscosity Coefficient  

Science Journals Connector (OSTI)

n...(1866) The shearing stress necessary to induce a unit velocity flow gradient in a material. In actual measurement, the viscosity coefficient of a material is obtained from...Physical Chemistry of...

Jan W. Gooch

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Magnetic Viscosity  

Science Journals Connector (OSTI)

1 January 1893 research-article Magnetic Viscosity J. Hopkinson E. Wilson F. Lydall The Royal Society is collaborating with JSTOR to digitize, preserve, and extend access to Proceedings of the Royal Society of London. www.jstor.org

1893-01-01T23:59:59.000Z

62

Nuclear viscosity  

Science Journals Connector (OSTI)

The decay rate of momentum in a nuclear reaction is given by an exact formula expressed in terms of the T matrix. A special case, where a viscosity coefficient can be estimated, is considered.

B. Giraud; J. Le Tourneux; E. Osnes

1975-01-01T23:59:59.000Z

63

Critical exponent for viscosity  

Science Journals Connector (OSTI)

We have measured the critical exponent y characterizing the divergence of the viscosity ???T-Tc?-y for carbon dioxide and xenon. The values of y for both fluids fall within the range y=0.041±0.001 and are consistent with the range y=0.042±0.002 spanned by our earlier data for four binary liquid mixtures. This agreement is the strongest evidence that pure fluids and binary liquids are in the same dynamic universality class; however, the results for y are inconsistent with the recent theoretical value of 0.032.

Robert F. Berg and Michael R. Moldover

1990-12-15T23:59:59.000Z

64

Viscosity of polymer solutions  

Science Journals Connector (OSTI)

Viscosity of polymer solutions ... Abstracts for Volume 5A, Number 2. This program contains three components: "Density of Liquids", "Viscosity of Liquids", and "Viscosity of Polymer Solutions". ...

Gary L. Bertrand

1992-01-01T23:59:59.000Z

65

Early dissipation and viscosity  

E-Print Network [OSTI]

We consider dissipative phenomena due to the relaxation of an initial anisotropic local pressure in the fireball created in relativistic heavy-ion collisions, both for the Bjorken boost-invariant case and for the azimuthally symmetric radial expansion with boost-invariance. The resulting increase of the entropy can be counterbalanced by a suitable retuning of the initial temperature. An increase of the transverse collective flow is observed. The influence of the shear viscosity on the longitudinal expansion is also studied. Viscosity reduces the cooling rate from the longitudinal work and counteracts the pressure gradients that accelerate the longitudinal flow.

Piotr Bozek

2008-04-24T23:59:59.000Z

66

Internal Viscosity of the Red Cell and a Blood Viscosity Equation  

Science Journals Connector (OSTI)

... The determination of the actual numerical values of the internal viscosity of the red cell is not simple. A direct ingress on the interior of ... visualized in which suspensions of the red cells could be studied in fluids of different viscosities. Such fluids could be solutions of high molecular weight dextran, solutions of macroglobulin or ...

LEOPOLD DINTENFASS

1968-08-31T23:59:59.000Z

67

Method to calculate resistance of high-speed displacement ship taking the effect of dynamic sinkage and trim and fluid viscosity into account  

Science Journals Connector (OSTI)

A method is presented to calculate the resistance of a high-speed displacement ship taking the effect of sinkage and trim and viscosity of ... mesh being used, the position of a ship is updated by the motion of “

Chao-bang Yao ???; Wen-cai Dong ???

2012-08-01T23:59:59.000Z

68

Viscosity, specific (for liquids)  

Science Journals Connector (OSTI)

n. The ratio between the viscosity of a liquid and the viscosity of water at the same temperature. Specific viscosity is sometimes used interchangeably with relative viscosity for liquids.

2007-01-01T23:59:59.000Z

69

Lunar Viscosity Models  

Science Journals Connector (OSTI)

31 March 1977 research-article Lunar Viscosity Models R. Meissner Viscosity values as estimated from isostatic processes and...depth seem to be connected with a limited range of viscosity values. A tentative relation between viscosity...

1977-01-01T23:59:59.000Z

70

Absolute viscosity  

Science Journals Connector (OSTI)

n. (1) Tangential force on unit area of either of two parallel planes at unit distance apart, when the space between the planes in filled with fluid (in question) and one of the planes moves with uni...

2007-01-01T23:59:59.000Z

71

Measurement of temperature-dependent thermal conductivity and viscosity of TiO{sub 2}-water nanofluids  

SciTech Connect (OSTI)

Nanofluid is an innovative heat transfer fluid with superior potential for enhancing the heat transfer performance of conventional fluids. Many attempts have been made to investigate its thermal conductivity and viscosity, which are important thermophysical properties. No definitive agreements have emerged, however, about these properties. This article reports the thermal conductivity and dynamic viscosity of nanofluids experimentally. TiO{sub 2} nanoparticles dispersed in water with volume concentration of 0.2-2 vol.% are used in the present study. A transient hot-wire apparatus is used for measuring the thermal conductivity of nanofluids whereas the Bohlin rotational rheometer (Malvern Instrument) is used to measure the viscosity of nanofluids. The data are collected for temperatures ranging from 15 C to 35 C. The results show that the measured viscosity and thermal conductivity of nanofluids increased as the particle concentrations increased and are higher than the values of the base liquids. Furthermore, thermal conductivity of nanofluids increased with increasing nanofluid temperatures and, conversely, the viscosity of nanofluids decreased with increasing temperature of nanofluids. Moreover, the measured thermal conductivity and viscosity of nanofluids are quite different from the predicted values from the existing correlations and the data reported by other researchers. Finally, new thermophysical correlations are proposed for predicting the thermal conductivity and viscosity of nanofluids. (author)

Duangthongsuk, Weerapun; Wongwises, Somchai [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab. (FUTURE), Department of Mechanical Engineering, King Mongkut's University of Technology Thonburi, 126 Bangmod, Bangkok 10140 (Thailand)

2009-04-15T23:59:59.000Z

72

Effective shear viscosity and dynamics of suspensions of micro-swimmers at moderate concentrations  

SciTech Connect (OSTI)

Recently, there have been a number of experimental studies suggesting that a suspension of self-propelled bacteria (microswimmers in general) may have an effective viscosity significantly smaller than the viscosity of the ambient fluid. This is in sharp contrast with suspensions of hard passive inclusions, whose presence always increases the viscosity. Here we present a 2D model for a suspension of microswimmers in a fluid and analyze it analytically in the dilute regime (no swimmer-swimmer interactions) and numerically using a Mimetic Finite Difference discretization. Our analysis shows that in the dilute regime the effective shear viscosity is not affected by self-propulsion. But at the moderate concentrations (due to swimmer-swimmer interactions) the effective viscosity decreases linearly as a function of the propulsion strength of the swimmers. These findings prove that (i) a physically observable decrease of viscosity for a suspension of self-propelled bacteria can be explained purely by hydrodynamic interactions and (ii) self-propulsion and interaction of swimmers are both essential to the reduction of the effective shear viscosity. We performed a number of numerical experiments analyzing the dynamics of swimmers resulting from pairwise interactions. The numerical results agree with the physically observed phenomena (e.g., attraction of swimmer to swimmer and swimmer to the wall). This is viewed as an additional validation of the model and the numerical scheme.

Constantin, Lipnikov [Los Alamos National Laboratory; Gyrya, V [PENNSYLVANIA STATE UNIV.; Aronson, I [ANL; Berlyand, L [PENNSYLVANIA STATE UNIV.

2009-01-01T23:59:59.000Z

73

Effective shear viscosity and dynamics of suspensions of micro-swimmers from small to moderate concentrations.  

SciTech Connect (OSTI)

Recently, there has been a number of experimental studies convincingly demonstrating that a suspension of self-propelled bacteria (microswimmers in general) may have an effective viscosity significantly smaller than the viscosity of the ambient fluid. This is in sharp contrast with suspensions of hard passive inclusions, whose presence always increases the viscosity. Here we present a 2D model for a suspension of microswimmers in a fluid and analyze it analytically in the dilute regime (no swimmer-swimmer interactions) and numerically using a Mimetic Finite Difference discretization. Our analysis shows that in the dilute regime (in the absence of rotational diffusion) the effective shear viscosity is not affected by self-propulsion. But at the moderate concentrations (due to swimmer-swimmer interactions) the effective viscosity decreases linearly as a function of the propulsion strength of the swimmers. These findings prove that (i) a physically observable decrease of viscosity for a suspension of self-propelled microswimmers can be explained purely by hydrodynamic interactions and (ii) self-propulsion and interaction of swimmers are both essential to the reduction of the effective shear viscosity. We also performed a number of numerical experiments analyzing the dynamics of swimmers resulting from pairwise interactions. The numerical results agree with the physically observed phenomena (e.g., attraction of swimmer to swimmer and swimmer to the wall). This is viewed as an additional validation of the model and the numerical scheme.

Gyrya, V.; Lipnikov, K.; Aranson, I.; Berlyand, L. (Materials Science Division); (Pennsylvania State Univ.); (LANL)

2011-05-01T23:59:59.000Z

74

Male gender, increased blood viscosity, body mass index and triglyceride levels are independently associated with systemic relative hypertension in sickle cell anemia  

E-Print Network [OSTI]

are independently associated with systemic relative hypertension in sickle cell anemia Yann Lamarre1,2,3 *, Marie: 2931, 3 tables, 0 figure Key words: Sickle cell anemia, relative hypertension, blood viscosity, vaso.1371/journal.pone.0066004 #12;2 Abstract: Patients with sickle cell anemia (SCA) have usually lower

Boyer, Edmond

75

Phonon Viscosity  

Science Journals Connector (OSTI)

The Boltzmann equation for thermal phonons in a dielectric crystal in the presence of a slowly varying but otherwise arbitrary, strain field is solved formally by expanding the phonon distribution function in terms of eigenfunctions of the collision operator. The macroscopic stress is then calculated in terms of the macroscopic strain and the phonon distribution function by using the quasiharmonic approximation. The resulting equation for the stress is of the same form as that given by thermoelasticity, except for the presence of an extra term which is linear in the strain rate. The coefficient of the strain rate in this term is identified with the phonon viscosity tensor, and a formal expression for this tensor is obtained.

H. J. MARIS

1969-12-15T23:59:59.000Z

76

Viscosity of meson matter  

Science Journals Connector (OSTI)

We report a calculation of the shear viscosity in a relativistic multicomponent meson gas as a function of temperature and chemical potentials. We approximately solve the Uehling-Uhlenbeck transport equation of kinetic theory, appropriate for a boson gas, with relativistic kinematics. Since at low temperatures the gas can be taken as mostly composed of pions, with a fraction of kaons and etas, we explore the region where binary elastic collisions with at least one pion are the dominant scattering processes. Our input meson scattering phase shifts are fits to the experimental data obtained from chiral perturbation theory and the inverse amplitude method. Our results take the correct nonrelativistic limit (viscosity proportional to the square root of the temperature), show a viscosity of the order of the cube of the pion mass up to temperatures somewhat below that mass, and then a large increase due to kaons and etas. Our approximation may break down at even higher temperatures, where the viscosity follows a temperature power law with an exponent near 3.

Antonio Dobado and Felipe J. Llanes-Estrada

2004-06-29T23:59:59.000Z

77

Viscosity and dissipation - early stages  

E-Print Network [OSTI]

A very early start up time of the hydrodynamic evolution is needed in order to reproduce observations from relativistic heavy-ion collisions experiments. At such early times the systems is still not locally equilibrated. Another source of deviations from local equilibrium is the viscosity of the fluid. We study these effects at very early times to obtain a dynamical prescription for the transition from an early 2-dimensional expansion to a nearly equilibrated 3-dimensional expansion at latter stages. The role of viscosity at latter stages of the evolution is also illustrated.

P. Bozek

2009-01-15T23:59:59.000Z

78

Evaluation of saponite and saponite/sepiolite fluids for geothermal drilling  

SciTech Connect (OSTI)

The rheology and other properties of drilling fluids containing saponite and a saponite-sepiolite mixture as the main vicosifier have been systematically evaluated in the temperature range of 300-600{degree}F under appropriate confining pressures up to 16,000 psi. Saponite represents the magnesium analog of the clay mineral montmorillonite, which is the main constituent in conventional bentonite-based fluids. The fluid with 6% saponite exhibits a prominent viscosity enhancement at temperatures above 250{degree}F. This viscosity enhancement is easily controlled by salts and hydroxides of Na and K. The addition of Na-polyacrylates (low- and high-molecular weight polymers) eliminates the viscosity anomaly of pure saponite fluids. These polymers also increase the filtration control of saponite. The anomalous viscosity enhancement of saponite is significantly reduced by the addition of sepiolite (a clay mineral with a fibrous morphology). 12 refs., 31 figs., 26 tabs.

Guven, N.; Panfil, D.J.; Carney, L.L. (Texas Tech Univ., Lubbock, TX (USA). Dept. of Geosciences)

1991-02-01T23:59:59.000Z

79

Viscosity of Metallic Liquids  

Science Journals Connector (OSTI)

... Viscosity measurements which have been recently carried out in this Department show that certain views normally ... not supported by experiments. For example, it is generally assumed1 that the relationship of viscosity to temperature is given by:

T. P. YAO; V. KONDIC

1950-09-16T23:59:59.000Z

80

Viscosity at RHIC  

E-Print Network [OSTI]

A variety of physical phenomena can lead to viscous effects. In this talk we review several sources of shear and bulk viscosity with an emphasis on the bulk viscosity associated with chiral restoration. We show that in the limit of a second order phase transition, the viscosity peaks in a singularity at the critical point.

Scott Pratt; Kerstin Paech

2006-04-03T23:59:59.000Z

Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Method for measuring liquid viscosity and ultrasonic viscometer  

DOE Patents [OSTI]

An ultrasonic viscometer and method for measuring fluid viscosity are provided. Ultrasonic shear and longitudinal waves are generated and coupled to the fluid. Reflections from the generated ultrasonic shear and longitudinal waves are detected. Phase velocity of the fluid is determined responsive to the detected ultrasonic longitudinal waves reflections. Viscosity of the fluid is determined responsive to the detected ultrasonic shear waves reflections. Unique features of the ultrasonic viscometer include the use of a two-interface fluid and air transducer wedge to measure relative signal change and to enable self calibration and the use of a ratio of reflection coefficients for two different frequencies to compensate for environmental changes, such as temperature.

Sheen, Shuh-Haw (Naperville, IL); Lawrence, William P. (Downers Grove, IL); Chien, Hual-Te (Naperville, IL); Raptis, Apostolos C. (Downers Grove, IL)

1994-01-01T23:59:59.000Z

82

Charm contribution to bulk viscosity  

E-Print Network [OSTI]

In the range of temperatures reached in future heavy ion collision experiments, hadronic pair annihilations and creations of charm quarks may take place within the lifetime of the plasma. As a result, charm quarks may increase the bulk viscosity affecting the early stages of hydrodynamic expansion. Assuming thermalization, we estimate the charm contribution to bulk viscosity within the same effective kinetic theory framework in which the light parton contribution has been computed previously. The time scale at which this physics becomes relevant is related to the width of the transport peak associated with the trace anomaly correlator, and is found to be 600 MeV.

Laine, M

2014-01-01T23:59:59.000Z

83

Charm contribution to bulk viscosity  

E-Print Network [OSTI]

In the range of temperatures reached in future heavy ion collision experiments, hadronic pair annihilations and creations of charm quarks may take place within the lifetime of the plasma. As a result, charm quarks may increase the bulk viscosity affecting the early stages of hydrodynamic expansion. Assuming thermalization, we estimate the charm contribution to bulk viscosity within the same effective kinetic theory framework in which the light parton contribution has been computed previously. The time scale at which this physics becomes relevant is related to the width of the transport peak associated with the trace anomaly correlator, and is found to be 600 MeV.

M. Laine; Kiyoumars A. Sohrabi

2014-10-24T23:59:59.000Z

84

Accelerating cosmological expansion from shear viscosity  

E-Print Network [OSTI]

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

Floerchinger, Stefan; Wiedemann, Urs Achim

2014-01-01T23:59:59.000Z

85

Bulk viscosity in heavy ion collision  

E-Print Network [OSTI]

The effect of a temperature dependent bulk viscosity to entropy density ratio~($\\zeta/s$) along with a constant shear viscosity to entropy density ratio~($\\eta/s$) on the space time evolution of the fluid produced in high energy heavy ion collisions have been studied in a relativistic viscous hydrodynamics model. The boost invariant Israel-Stewart theory of causal relativistic viscous hydrodynamics is used to simulate the evolution of the fluid in 2 spatial and 1 temporal dimension. The dissipative correction to the freezeout distribution for bulk viscosity is calculated using Grad's fourteen moment method. From our simulation we show that the method is applicable only for $\\zeta/s<0.004$.

Victor Roy; A. K. Chaudhuri

2012-01-20T23:59:59.000Z

86

Bulk viscosity in nuclear and quark matter: A short review  

E-Print Network [OSTI]

The history and recent progresses in the study of bulk viscosity in nuclear and quark matter are reviewed. The constraints from baryon number conservation and electric neutrality in quark matter on particle densities and fluid velocity divergences are discussed.

Hui Dong; Nan Su; Qun Wang

2007-02-07T23:59:59.000Z

87

Solvent viscosity mismatch between the solute plug and the mobile phase: Considerations in the applications of two-dimensional HPLC  

SciTech Connect (OSTI)

Understanding the nature of viscosity contrast induced flow instabilities is an important aspect in the design of two-dimensional HPLC separations. When the viscosity contrast between the sample plug and the mobile phase is sufficiently large, the phenomenon known as viscous fingering can be induced. Viscous fingering is a flow instability phenomenon that occurs at the interface between two fluids with different viscosities. In liquid chromatography, viscous fingering results in the solute band undergoing a change in form as it enters into the chromatography column. Moreover, even in the absence of viscous fingering, band shapes change shape at low viscosity contrasts. These changes can result in a noticeable change in separation performance, with the result depending on whether the solvent pushing the solute plug has a higher or lower viscosity than the solute plug. These viscosity induced changes become more important as the solute injection volume increases and hence understanding the process becomes critical in the implementation of multidimensional HPLC techniques, since in these techniques the sample injection plug into the second dimension is an order of magnitude greater than in one-dimensional HPLC. This review article assesses the current understanding of the viscosity contrast induced processes as they relate to liquid chromatographic separation behaviour.

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

2010-01-01T23:59:59.000Z

88

INCREASE  

ScienceCinema (OSTI)

The Interdisciplinary Consortium for Research and Educational Access in Science and Engineering (INCREASE), assists minority-serving institutions in gaining access to world-class research facilities.

None

2013-07-22T23:59:59.000Z

89

Viscosity of Silicate Melts.  

E-Print Network [OSTI]

??Viscosity of silicate melts is of fundamental importance in understanding volcanic and magmatic processes in Earth. In this dissertation, experiments were conducted to obtain high-pressure… (more)

Hui, Hejiu

2008-01-01T23:59:59.000Z

90

Viscosity, Absolute Dynamic  

Science Journals Connector (OSTI)

where A is the area (cm2). (dv/dx) is the velocity gradient (s?1...), and ? is the coefficient of absolute viscosity (poise).

Jan W. Gooch

2011-01-01T23:59:59.000Z

91

Viscosity, absolute dynamic  

Science Journals Connector (OSTI)

where A is the area (cm2), (dv/dx) the velocity gradient (s–1), and ? is the coefficient of absolute viscosity (poise).

2007-01-01T23:59:59.000Z

92

Viscosity of Neopentane  

Science Journals Connector (OSTI)

The viscosity of neopentane has been measured between ?15°C and 30°C. These results are consistent with published work covering the temperature range 30°C to 150°C. The viscosity data for neopentane have been compared with similar data for the other pentanes. This comparison has provided an example of the importance of molecular shape for viscosity behavior. The possible significance of molecular shape for the interpretation of viscosity curves of binary mixtures is noted. Finally it has been suggested that further work on liquids composed of spherical molecules might be worthwhile.

M. K. Phibbs

1951-01-01T23:59:59.000Z

93

Viscosity Measurements with Glass  

Science Journals Connector (OSTI)

1 May 1925 research-article Viscosity Measurements with Glass Vaughan H. Stott Edith Irvine D. Turner The Royal Society is collaborating with JSTOR to digitize, preserve...

1925-01-01T23:59:59.000Z

94

VISCOSITY OF NEMATIC-CHIRAL MIXTURES AND THEIR ELECTROOPTICAL CHARACTERISTICS  

E-Print Network [OSTI]

VISCOSITY OF NEMATIC-CHIRAL MIXTURES AND THEIR ELECTROOPTICAL CHARACTERISTICS Z. M. ELASHVILI, M. D of Georgian SSR, Tbilisi 380086, S. Euli str. 5, USSR Abstract. -- We have measured the viscosity in mixtures that the increase of the viscosity at low additive concentration (Cm

Boyer, Edmond

95

Nonequilibrium viscosity of glass  

Science Journals Connector (OSTI)

Since glass is a nonequilibrium material, its properties depend on both composition and thermal history. While most prior studies have focused on equilibrium liquid viscosity, an accurate description of nonequilibrium viscosity is essential for understanding the low temperature dynamics of glass. Departure from equilibrium occurs as a glass-forming system is cooled through the glass transition range. The glass transition involves a continuous breakdown of ergodicity as the system gradually becomes trapped in a subset of the available configurational phase space. At very low temperatures a glass is perfectly nonergodic (or “isostructural”), and the viscosity is described well by an Arrhenius form. However, the behavior of viscosity during the glass transition range itself is not yet understood. In this paper, we address the problem of glass viscosity using the enthalpy landscape model of Mauro and Loucks [Phys. Rev. B 76, 174202 (2007)] for selenium, an elemental glass former. To study a wide range of thermal histories, we compute nonequilibrium viscosity with cooling rates from 10?12 to 1012?K/s. Based on these detailed landscape calculations, we propose a simplified phenomenological model capturing the essential physics of glass viscosity. The phenomenological model incorporates an ergodicity parameter that accounts for the continuous breakdown of ergodicity at the glass transition. We show a direct relationship between the nonequilibrium viscosity parameters and the fragility of the supercooled liquid. The nonequilibrium viscosity model is validated against experimental measurements of Corning EAGLE XG™ glass. The measurements are performed using a specially designed beam-bending apparatus capable of accurate nonequilibrium viscosity measurements up to 1016?Pa?s. Using a common set of parameters, the phenomenological model provides an accurate description of EAGLE XG™ viscosity over the full range of measured temperatures and fictive temperatures.

John C. Mauro; Douglas C. Allan; Marcel Potuzak

2009-09-30T23:59:59.000Z

96

Shear viscosity and spectral function of the quark matter  

E-Print Network [OSTI]

We discuss the shear viscosity of the quark matter by using the Kubo-Mori formula. It is found that the shear viscosity is expressed in terms of the quark spectral function. If the spectral function is approximated by a modified Bright-Wigner type, the viscosity decreases as the width of the spectral function increases. We also discuss dependence of the shear viscosity on the temperature and the density.

Masaharu Iwasaki; Hiromasa Ohnishi; Takahiko Fukutome

2006-06-19T23:59:59.000Z

97

Multipurpose Acoustic Sensor for Downhole Fluid Monitoring  

Broader source: Energy.gov [DOE]

Novel sensor design based on acoustics. Determine in real-timeand in a single sensor packagemultiple parameters: temperature, pressure, fluid flow; and fluid properties, such as density, viscosity, fluid composition.

98

The Viscosity of Liquids  

Science Journals Connector (OSTI)

... of momentum between them. In the case of a gas, Maxwell showed how the viscosity can be derived by considering this momentum as being communicated by molecules transferring themselves bodily ... fulfilment of the conditions postulated in Maxwell's treatment, and the fact that while gas viscosity goes up with temperature liquid ...

E. N. DA C. ANDRADE

1930-04-12T23:59:59.000Z

99

Viscosity model of high-viscosity dispersing system  

Science Journals Connector (OSTI)

High-viscosity dispersing system is formed by dispersing the solid particles in the high-viscosity continuous medium. It is very easy to ... the rheology behavior becomes complicated. The apparent viscosity of th...

Xian-fu Wei ???; Na Wang ??…

2008-09-01T23:59:59.000Z

100

Viscosity of Bacterial Suspensions: Hydrodynamic Interactions and Self-Induced Noise Shawn D. Ryan,1, 2  

E-Print Network [OSTI]

Viscosity of Bacterial Suspensions: Hydrodynamic Interactions and Self-Induced Noise Shawn D. Ryan, 2011) The viscosity of a suspension of swimming bacteria is investigated analytically and numerically fluid, result in a dramatic reduction of the effective viscosity. In agreement with experiments

Berlyand, Leonid

Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Viscosity of -pinene secondary organic material and implications for particle growth and reactivity  

E-Print Network [OSTI]

Viscosity of -pinene secondary organic material and implications for particle growth and reactivity of secondary organic material (SOM) are abun- dant in the lower troposphere. The viscosity of these particles-mobility" technique and a "poke-flow" technique, in conjunction with simulations of fluid flow, the viscosity

102

Apparatus and method for measuring viscosity  

DOE Patents [OSTI]

The present invention is directed to an apparatus and method for measuring the viscosity of a fluid. This apparatus and method is particularly useful for the measurement of the viscosity of a liquid in a harsh environment characterized by high temperature and the presence of corrosive or deleterious gases and vapors which adversely affect conventional ball or roller bearings. The apparatus and method of the present invention employ one or more flexural or torsional bearings to suspend a bob capable of limited angular motion within a rotatable sleeve suspended from a stationary frame. 7 figs.

Murphy, R.J. Jr.

1986-02-25T23:59:59.000Z

103

Apparatus and method for measuring viscosity  

DOE Patents [OSTI]

The present invention is directed to an apparatus and method for measuring the viscosity of a fluid. This apparatus and method is particularly useful for the measurement of the viscosity of a liquid in a harsh environment characterized by high temperature and the presence of corrosive or deleterious gases and vapors which adversely affect conventional ball or roller bearings. The apparatus and method of the present invention employ one or more flexural or torsional bearings to suspend a bob capable of limited angular motion within a rotatable sleeve suspended from a stationary frame.

Murphy, Jr., Robert J. (Bellaire, TX)

1986-01-01T23:59:59.000Z

104

Modeling multiphase flow for high viscosity liquids: a study of vertical/inclined zero net liquid flow  

E-Print Network [OSTI]

° for higher viscosities. The trend suggests that the flow distribution coefficient, C[], varies with fluid viscosity and inclination angle, therefore affecting the liquid holdup in the pipe. A new model is proposed to take into account these factors and its...

Rodriguez, Jose Ramon

2012-06-07T23:59:59.000Z

105

Accurate viscosity modeling of liquid metals based on friction theory and PC-SAFT equation of state  

Science Journals Connector (OSTI)

Values of the viscosities of liquid metals are important in the prediction of fluid flow in many metallurgical manufacturing processes. In this work the friction theory (f-theory...) for viscosity modeling is use...

M. H. Mousazadeh

2012-06-01T23:59:59.000Z

106

Viscosity Measurements on Gaseous Ethane  

Science Journals Connector (OSTI)

Viscosity Measurements on Gaseous Ethane ... Only the pressures, densities, and viscosities are given in the table with regard to the large number of experimental points. ...

Jörg Wilhelm; Daniel Seibt; Eckhard Vogel; Daniel Buttig; Egon Hassel

2005-11-08T23:59:59.000Z

107

Energy-momentum tensor correlators and viscosity  

E-Print Network [OSTI]

Collective flow has been observed in heavy ion collisions, with a large anisotropic component, and ideal hydrodynamic calculations had significant successful in describing the distribution of produced particles at the RHIC experiments. In order to account for this near ideal fluid behavior, the shear and bulk viscosity of the quark gluon plasma (QGP) must be computed from first principles in a regime where the QGP is not weakly coupled. In this talk I describe recent progress in computing energy-momentum tensor correlators on the lattice from which the viscosities can be extracted via Kubo formulas. I also show how to cumulate information from several channels, including at non-vanishing spatial momentum, in order to best constrain the viscosities. These methods should soon yield predictions at the higher temperatures that will be explored at the LHC experiments.

Harvey B. Meyer

2008-09-30T23:59:59.000Z

108

The Viscosity of Ammonia  

Science Journals Connector (OSTI)

A new representation of the viscosity of ammonia is presented. The representative equations are based on a set of experimental data selected as a result of a critical assessment of the available information. The validity of the representation extends from 196 K to the critical temperature for both liquid and vapor phases. In the supercritical region the temperature range extends to 680 K for pressures at or below ambient and to 600 K for pressures up to 50 MPa. The accuracy of the representation varies from 0.5% for the viscosity of the dilute gas phase at moderate temperatures to about 5% for the viscosity at high pressures and temperatures. Tables of the viscosity generated by the correlating equation at selected temperatures and pressures and along the saturation line are presented to provide easy reference as well as for the validation of computer codes.

A. Fenghour; William A. Wakeham; V. Vesovic; J. T. R. Watson; J. Millat; E. Vogel

1995-01-01T23:59:59.000Z

109

The Viscosity of Ice  

Science Journals Connector (OSTI)

11 September 1908 research-article The Viscosity of Ice R. M. Deeley The Royal Society is collaborating with JSTOR to digitize, preserve, and extend access to Proceedings of...

1908-01-01T23:59:59.000Z

110

Viscosity and Riemann solutions On the Influence of Viscosity on  

E-Print Network [OSTI]

Viscosity and Riemann solutions On the Influence of Viscosity on Riemann Solutions SunŸcica Ÿ Cani and uniqueness of Riemann solutions are affected by the precise form of viscosity which is used to select shock on viscosity and distinguish between Lax shock waves with and without a profile. These bifurcations

Canic, Suncica

111

Shear viscosity of hadronic gas mixtures  

E-Print Network [OSTI]

We investigate the effects of baryon chemical potential \\mu on the shear viscosity coefficient \\eta and the viscosity to entropy density ratio \\eta/s of a pion-nucleon gas mixture. We find that \\eta is an increasing function of T and \\mu, while the ratio \\eta/s turns to a decreasing function in a wide region of T-\\mu plane. In the kinematical region we studied, the smallest value of \\eta/s is about 0.3.

K. Itakura; O. Morimatsu; H. Otomo

2008-05-12T23:59:59.000Z

112

Bulk viscosity in a cold CFL superfluid  

E-Print Network [OSTI]

We compute one of the bulk viscosity coefficients of cold CFL quark matter in the temperature regime where the contribution of mesons, quarks and gluons to transport phenomena is Boltzmann suppressed. In that regime dissipation occurs due to collisions of superfluid phonons, the Goldstone modes associated to the spontaneous breaking of baryon symmetry. We first review the hydrodynamics of relativistic superfluids, and remind that there are at least three bulk viscosity coefficients in these systems. We then compute the bulk viscosity coefficient associated to the normal fluid component of the superfluid. In our analysis we use Son's effective field theory for the superfluid phonon, amended to include scale breaking effects proportional to the square of the strange quark mass m_s. We compute the bulk viscosity at leading order in the scale breaking parameter, and find that it is dominated by collinear splitting and joining processes. The resulting transport coefficient is zeta=0.011 m_s^4/T, growing at low temperature T until the phonon fluid description stops making sense. Our results are relevant to study the rotational properties of a compact star formed by CFL quark matter.

Cristina Manuel; Felipe Llanes-Estrada

2007-05-26T23:59:59.000Z

113

Viscosity of aqueous and cyanate ester suspensions containing alumina nanoparticles  

SciTech Connect (OSTI)

The viscosities of both aqueous and cyanate ester monomer (BECy) based suspensions of alumina nanoparticle were studied. The applications for these suspensions are different: aqueous suspensions of alumina nanoparticles are used in the production of technical ceramics made by slip casting or tape casting, and the BECy based suspensions are being developed for use in an injection-type composite repair resin. In the case of aqueous suspensions, it is advantageous to achieve a high solids content with low viscosity in order to produce a high quality product. The addition of a dispersant is useful so that higher solids content suspensions can be used with lower viscosities. For BECy suspensions, the addition of nanoparticles to the BECy resin is expected to enhance the mechanical properties of the cured composite. The addition of saccharides to aqueous suspensions leads to viscosity reduction. Through DSC measurements it was found that the saccharide molecules formed a solution with water and this resulted in lowering the melting temperature of the free water according to classic freezing point depression. Saccharides also lowered the melting temperature of the bound water, but this followed a different rule. The shear thinning and melting behaviors of the suspensions were used to develop a model based on fractal-type agglomeration. It is believed that the structure of the particle flocs in these suspensions changes with the addition of saccharides which leads to the resultant viscosity decrease. The viscosity of the BECy suspensions increased with solids content, and the viscosity increase was greater than predicted by the classical Einstein equation for dilute suspensions. Instead, the Mooney equation fits the viscosity behavior well from 0-20 vol% solids. The viscosity reduction achieved at high particle loadings by the addition of benzoic acid was also investigated by NMR. It appears that the benzoic acid interacts with the surface of the alumina particle which may be the cause of the viscosity reduction. The flow behavior of alumina particles in water and BECy is markedly different. Aqueous alumina suspensions are shear thinning at all alumina loadings and capable of 50 vol% loading before losing fluidity whereas BECy/alumina suspensions show Newtonian behavior up to 5 vol%, and above 5 vol% show shear thinning at all shear rates. Highly loaded suspensions (i.e. 20vol% alumina) exhibit shear thinning at low and moderate shear rates and shear thickening at higher shear rates. The maximum particle loading for a fluid suspension, in this case, appears to be about 20 vol%. The difference in the viscosity of these suspensions must be related to the solvent-particle interactions for each system. The reason is not exactly known, but there are some notable differences between BECy and water. Water molecules are {approx}0.28 nm in length and highly hydrogen bonded with a low viscosity (1 mPa's) whereas in the cyanate ester (BECy) system, the solvent molecule is about 1.2 nm, in the largest dimension, with surfaces of varied charge distribution throughout the molecule. The viscosity of the monomer is also reasonably low for organic polymer precursor, about 7 mPa's. Nanoparticles in water tend to agglomerate and form flocs which are broken with the shear force applied during viscosity measurement. The particle-particle interaction is very important in this system. In BECy, the particles appear to be well dispersed and not as interactive. The solvent-particle interaction appears to be most important. It is not known exactly how the alumina particles interact with the monomer, but NMR suggests hydrogen bonding. These hydrogen bonds between the particle and monomer could very well affect the viscosity. A conclusion that can be reached in this work is that the presence of hydroxyl groups on the surface of the alumina particles is significant and seems to affect the interactions between other particles and the solvent. Thus, the hydrogen bonding between particles, particle/additive and/or particle/solvent dictates the behavior of nanos

Lawler, Katherine

2009-08-05T23:59:59.000Z

114

VISCOSITY IN PLANETARY RINGS WITH SPINNING SELF-GRAVITATING PARTICLES  

SciTech Connect (OSTI)

Using local N-body simulation, we examine viscosity in self-gravitating planetary rings. We investigate the dependence of viscosity on various parameters in detail, including the effects of particle surface friction. In the case of self-gravitating rings with low optical depth, viscosity is determined by particle random velocity. Inclusion of surface friction slightly reduces both random velocity and viscosity when particle random velocity is determined by inelastic collisions, while surface friction slightly increases viscosity when gravitational encounters play a major role in particle velocity evolution, so that viscous heating balances with increased energy dissipation at collisions due to surface friction. We find that including surface friction changes viscosity in dilute rings up to a factor of about two. In the case of self-gravitating dense rings, viscosity is significantly increased due to the effects of gravitational wakes, and we find that varying restitution coefficients also change viscosity in such dense rings by a factor of about two. We confirm that our numerical results for viscosity in dense rings with gravitational wakes can be well approximated by a semianalytic expression that is consistent with a previously obtained formula. However, we find that this formula seems to overestimate viscosity in dense rings far from the central planet, where temporary gravitational aggregates form. We derive semianalytic expressions that reproduce our numerical results well for the entire range of examined parameters.

Yasui, Yuki; Ohtsuki, Keiji [Department of Earth and Planetary Sciences, Kobe University, Kobe 657-8501 (Japan); Daisaka, Hiroshi [Graduate School of Commerce and Management, Hitotsubashi University, Tokyo 186-8601 (Japan)

2012-05-15T23:59:59.000Z

115

Viscosity of Interfacial Water  

Science Journals Connector (OSTI)

The effective shear viscosity and frequency-dependent dynamic oscillatory shear spectra of water containing monovalent or divalent ions (ionic strength 25 mM), confined between mica crystals at 1–2 water molecules thickness, oscillated with twist angle with the period expected for the pseudohexagonal surface lattice. The effective viscosity varied by orders of magnitude as the twist angle was changed. Confinement appeared to imprint lateral spatial correlation on the ultrathin liquid, the more so the better the confining lattices were aligned, but the oft-proposed “ice structure” was not observed dynamically.

Yingxi Zhu and Steve Granick

2001-08-10T23:59:59.000Z

116

Viscosity and Lubrication  

Science Journals Connector (OSTI)

... oils in the tubes supplied. Further, each laboratory was invited to report the kinematic viscosity of the oils in absolute units at 20° C, according to the method used ... tubes may be selected from a set of apparently equally good tubes.

1945-06-16T23:59:59.000Z

117

Viscosity of Liquids  

Science Journals Connector (OSTI)

6 November 1952 research-article Viscosity of Liquids E. N. da C. Andrade The Royal Society is collaborating with JSTOR to digitize, preserve, and extend access to Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences. www.jstor.org

1952-01-01T23:59:59.000Z

118

Viscosity Effects in Acoustic Inductances  

Science Journals Connector (OSTI)

The linear acousticinductance and resistance of narrow circular tubes short compared to a wavelength have usually been represented by limiting formulas valid either for very low frequencies (viscous flow) or for relatively high frequencies (pistonlike displacement). Crandall's text gives a general mathematical development with particular stress on resistance but variation of inductance with frequency and viscosity has not been discussed generally nor has numerical reduction of mathematical results been generally available. The present paper describes quantitatively the dependence of inductance and resistance upon the general parameter radius times square root of the quantity density times frequency divided by viscosity. With increase of this parameter resistance increases while inductance diminishes from the “static” value to the limiting “high frequency” value. Experimental checks are made to ascertain whether resistance values are strongly affected by flow?transition end?effects found in hydraulics. Impedance?tube studies are made of five tube diameters from 0.0187 to 0.750 in. at 50 to 167 c/sec. Length/diameter is approximately 10 to render inductance end?corrections relatively small. Acoustic pressures are reduced until linear behavior appears. Measured resistance is generally within five percent of calculation as resistance increases to twice the “static” value. Measured inductance generally agrees with calculation within limits of the end?correction over the range of significant variation.

A. W. Nolle

1951-01-01T23:59:59.000Z

119

Viscosity Dependence of the Rotational Reorientation of Rhodamine B in Mono-and Polyalcohols. Picosecond Transient Grating Experiments  

E-Print Network [OSTI]

Viscosity Dependence of the Rotational Reorientation of Rhodamine B in Mono- and Polyalcohols-Stokes-Einstein (DSE) theorywas shown to extend to much higher viscosities than previously reported. Detailed of radius R and hydrodynamic volume V rotating in a fluid continuum of macroscopic viscosity q and relates

Fayer, Michael D.

120

Note: Precision viscosity measurement using suspended microchannel resonators  

SciTech Connect (OSTI)

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

Lee, I.; Lee, J. [Department of Mechanical Engineering, Sogang University, Seoul 121-742 (Korea, Republic of); Park, K. [Department of Mechanical, Industrial, and Systems Engineering, University of Rhode Island, Kingston, Rhode Island 02881 (United States)

2012-11-15T23:59:59.000Z

Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Freeze-out by bulk viscosity driven instabilities  

E-Print Network [OSTI]

We describe a new scenario (first introduced in [G. Torrieri, B. Tom\\'a\\v{s}ik and I. Mishustin, Phys. Rev. C \\textbf{77}, 034903 (2008)]) for freezeout in heavy ion collisions that could solve the lingering problems associated with the so-called HBT puzzle. We argue that bulk viscosity increases as $T$ approaches $T_c$. The fluid {then} becomes unstable against small perturbations, and fragments into clusters of a size much smaller than the total size of the system. These clusters maintain the pre-existing outward-going flow, as a spray of droplets, but develop no flow of their own, and hadronize by evaporation. We show that this scenario can explain HBT data and suggest how it can be experimentally tested.

Torrieri, Giorgio; Mishustin, Igor

2008-01-01T23:59:59.000Z

122

Viscosity Measurements on Gaseous Propane  

Science Journals Connector (OSTI)

Viscosity Measurements on Gaseous Propane ... However, in that case, the viscosities will have to be re-evaluated too, which also requires the parameters of the wire oscillation, the logarithmic decrement and the frequency. ...

Jörg Wilhelm; Eckhard Vogel

2001-09-25T23:59:59.000Z

123

Studying rheological behavior of nanoclay as oil well drilling fluid  

Science Journals Connector (OSTI)

Bentonite is commonly used to control the rheology and filtrate loss required for water-based drilling fluids. In this study, the effect ... modification on fluid viscosity and its dispersion in oil-wet fluids we...

M. Mohammadi; M. Kouhi; A. Sarrafi; M. Schaffie

2013-09-01T23:59:59.000Z

124

Viscosity-average molecular weight  

Science Journals Connector (OSTI)

n .... An averaged molecular weight for high polymers that relates most closely to measurements of dilute-solution viscosities ...

2007-01-01T23:59:59.000Z

125

Viscosity of Ring Polymer Melts  

Science Journals Connector (OSTI)

Viscosity of Ring Polymer Melts ... The ratio of the zero-shear viscosities of linear polymer melts ?0,linear to their ring counterparts ?0,ring at isofrictional conditions is discussed as a function of the number of entanglements Z. ... For this reason we have determined the viscosities by fitting the complex viscosity curves with different methods to obtain reliable estimates and error bars (see Supporting Information). ...

Rossana Pasquino; Thodoris C. Vasilakopoulos; Youn Cheol Jeong; Hyojoon Lee; Simon Rogers; George Sakellariou; Jürgen Allgaier; Atsushi Takano; Ana R. Brás; Taihyun Chang; Sebastian Gooßen; Wim Pyckhout-Hintzen; Andreas Wischnewski; Nikos Hadjichristidis; Dieter Richter; Michael Rubinstein; Dimitris Vlassopoulos

2013-09-17T23:59:59.000Z

126

Rheological Behavior of Xanthan Gum Solution Related to Shear Thinning Fluid Delivery for Subsurface Remediation  

SciTech Connect (OSTI)

Xanthan gum, a biopolymer, forms shear thinning fluids which can be used as delivery media to improve the distribution of remedial amendments injected into heterogeneous subsurface environments. The rheological behavior of the shear thinning solution needs to be known to develop an appropriate design for field injection. In this study, the rheological properties of xanthan gum solutions were obtained under various chemical and environmental conditions relevant to delivery of remedial amendments to groundwater. Higher xanthan concentration raised the absolute solution viscosity and increased the degree of shear thinning. Addition of remedial amendments (e.g., phosphate, sodium lactate, ethyl lactate) caused the dynamic viscosity of xanthan gum to decrease, but the solutions maintained shear-thinning properties. Use of simple salt (e.g. Na+, Ca2+) to increase the solution ionic strength also decreased the dynamic viscosity of xanthan and the degree of shear thinning, although the effect is a function of xanthan gum concentration and diminished as the xanthan gum concentration was increased. At high xanthan concentration, addition of salt to the solution increased dynamic viscosity. In the absence of sediments, xanthan gum solutions maintain their viscosity properties for months. However, xanthan gum solutions were shown to lose dynamic viscosity over a period of days to weeks when contacted with saturated site sediment. Loss of viscosity is attributed to physical and biodegradation processes.

Zhong, Lirong; Oostrom, Martinus; Truex, Michael J.; Vermeul, Vincent R.; Szecsody, James E.

2013-01-15T23:59:59.000Z

127

Viscosity in spherically symmetric accretion  

Science Journals Connector (OSTI)

......October 2003 research-article Papers Viscosity in spherically symmetric accretion Arnab...Calcutta 700 032, India The influence of viscosity on the flow behaviour in spherically...at least for the transonic solution, viscosity acts as a mechanism that detracts from......

Arnab K. Ray

2003-10-01T23:59:59.000Z

128

Viscosity of silica  

Science Journals Connector (OSTI)

Experimental measurements of the viscosity of silica ( SiO 2 ) are critically examined; the best measurements show an activation energy of 515 kJ/mole above 1400 °C and 720 kJ/mole below this temperature. The diffusion of silicon and oxygen in silica have temperature dependencies close to that of the high temperature viscosity. Mechanisms of viscous flow and diffusion of silicon and oxygen in silica are proposed that involve motion of SiO molecules. Viscous flow is proposed to result from the motion of line defects composed of SiO molecules At temperatures below 1400 °C the fraction of SiO molecules in line defects changes with temperature. The relaxation of this fraction to an equilibrium value depends on the time. These proposed mechanisms are consistent with experimental measurements of silicaviscosity.

Robert H. Doremus

2002-01-01T23:59:59.000Z

129

Viscosity of high-temperature iodine  

Science Journals Connector (OSTI)

The viscosity coefficient of iodine in the temperature range 500?T?3000 K is calculated. Because of the low dissociation energy of the I2 molecules, the dissociation degree of the gas increases quickly with temperature, and I+I2 and I+I collisions must be taken into account in calculations of viscosity at temperatures greater than 1000°. Several possible channels for atom-atom interaction are considered, and the resulting collision integrals are averaged over all the important channels. It is also shown that the rigid-sphere model is inaccurate in predictions of the viscosity. The approach of the present work is general and can be used for other diatomic gases with arbitrary dissociation degree.

Steve H. Kang and Joseph A. Kunc

1991-09-15T23:59:59.000Z

130

Viscosity Destabilizes Sonoluminescing Bubbles  

Science Journals Connector (OSTI)

In single-bubble sonoluminescence (SBSL) microbubbles are trapped in a standing sound wave, typically in water or water-glycerol mixtures. However, in viscous liquids such as glycol, methylformamide, or sulphuric acid it is not possible to trap the bubble in a stable position. This is very peculiar as larger viscosity normally stabilizes the dynamics. Suslick and co-workers call this new mysterious state of SBSL “moving-SBSL.” We identify the history force (a force nonlocal in time) as the origin of this destabilization and show that the instability is parametric. A force balance model quantitatively accounts for the observed quasiperiodic bubble trajectories.

Ruediger Toegel; Stefan Luther; Detlef Lohse

2006-03-20T23:59:59.000Z

131

Viscosity near phase transitions  

E-Print Network [OSTI]

Probably the most enticing observation in theoretical physics during the last decade was the discovery of the great amount of consequences obtained from the AdS/CFT conjecture put forward by Maldacena. In this work we review how this correspondence can be used to address hydrodynamic properties such as the viscosity of some strongly interacting systems. We also employ the Boltzmann equation for those systems closer to low-energy QCD, and argue that this kind of transport coefficients can be related to phase transitions, in particular the QGP/hadronic phase transition studied in heavy ion collisions.

Antonio Dobado; Felipe J. Llanes-Estrada; Juan M. Torres-Rincon

2010-09-30T23:59:59.000Z

132

Shear viscosity of nuclear matter  

E-Print Network [OSTI]

In this talk I report my recent study on the shear viscosity of neutron-rich nuclear matter from a relaxation time approach. An isospin- and momentum-dependent interaction is used in the study. Effects of density, temperature, and isospin asymmetry of nuclear matter on its shear viscosity have been discussed. Similar to the symmetry energy, the symmetry shear viscosity is defined and its density and temperature dependence are studied.

Jun Xu

2013-02-01T23:59:59.000Z

133

The Viscosity of Carbon Dioxide  

Science Journals Connector (OSTI)

26 July 1912 research-article The Viscosity of Carbon Dioxide P. Phillips The Royal Society is collaborating with JSTOR to digitize, preserve, and extend access to Proceedings...

1912-01-01T23:59:59.000Z

134

Combined effect of viscosity and vorticity on single mode Rayleigh-Taylor instability bubble growth  

SciTech Connect (OSTI)

The combined effect of viscosity and vorticity on the growth rate of the bubble associated with single mode Rayleigh-Taylor instability is investigated. It is shown that the effect of viscosity on the motion of the lighter fluid associated with vorticity accumulated inside the bubble due to mass ablation may be such as to reduce the net viscous drag on the bubble exerted by the upper heavier fluid as the former rises through it.

Banerjee, Rahul; Mandal, Labakanta; Roy, S.; Khan, M.; Gupta, M. R. [Department of Instrumentation Science and Centre for Plasma Studies, Jadavpur University, Kolkata 700032 (India)

2011-02-15T23:59:59.000Z

135

Saturation of elliptic flow and shear viscosity  

E-Print Network [OSTI]

Effect of shear viscosity on elliptic flow is studied in causal dissipative hydrodynamics in 2+1 dimensions. Elliptic flow is reduced in viscous dynamics. Causal evolution of minimally viscous fluid ($\\eta/s$=0.08), can explain the PHENIX data on elliptic flow in 16-23% Au+Au collisions up to $p_T\\approx$3.6 GeV. In contrast, ideal hydrodynamics, can explain the same data only up to $p_T\\approx$1.5 GeV. $p_T$ spectra of identified particles are also better explained in minimally viscous fluid than in ideal dynamics. However, saturation of elliptic flow at large $p_T$ is not reproduced.

A. K. Chaudhuri

2007-08-09T23:59:59.000Z

136

Viscosity-Dependent Protein Dynamics Ilya J. Finkelstein, Aaron M. Massari, and M. D. Fayer  

E-Print Network [OSTI]

Viscosity-Dependent Protein Dynamics Ilya J. Finkelstein, Aaron M. Massari, and M. D. Fayer viscosity at room temperature in four heme proteins: hemoglobin, myoglobin, a myoglobin mutant replaced by an alanine (M61A). Fructose is added to increase the viscosity of the aqueous protein solutions

Fayer, Michael D.

137

Shear viscosity and shear thinning in two-dimensional Yukawa , J. Goree2  

E-Print Network [OSTI]

Shear viscosity and shear thinning in two-dimensional Yukawa liquids Z. Donk´o1 , J. Goree2 , P using two different nonequi- librium molecular dynamics simulation methods. Shear viscosity values.e., the viscosity diminishes with increasing shear rate. It is expected that two-dimensional dusty plasmas

Goree, John

138

Viscosity and termal conductivity of nanofluids containing mult-walled carbon nanotubes stabilized by chitosan.  

SciTech Connect (OSTI)

Thermal conductivity, viscosity, and stability of nanofluids containing multi-walled carbon nanotubes (MWCNTs) stabilized by cationic chitosan were studied. Chitosan with weight fraction of 0.1%, 0.2 wt%, and 0.5 wt% was used to disperse stably MWCNTs in water. The measured thermal conductivity showed an enhancement from 2.3% to 13% for nanofluids that contained from 0.5 wt% to 3 wt% MWCNTs (0.24 to 1.43 vol %). These values are significantly higher than those predicted using the Maxwell's theory. We also observed that the enhancements were independent of the base fluid viscosity. Thus, use of microconvection effect to explain the anomalous thermal conductivity enhancement should be reconsidered. MWCNTs can be used either to enhance or reduce the fluid base viscosity depending on the weight fractions. In the viscosity-reduction case, a reduction up to 20% was measured by this work. In the viscosity-enhancement case, the fluid behaved as a non-Newtonian shear-thinning fluid. By assuming that MWCNT nanofluids behave as a generalized second grade fluid where the viscosity coefficient depends upon the rate of deformation, a theoretical model has been developed. The model was found to describe the fluid behavior very well.

Tran, P.X.: Massoudi, M: Chen, R.H.

2011-01-01T23:59:59.000Z

139

The Viscosity of Air  

Science Journals Connector (OSTI)

The viscosity of air has been remeasured with the rotating cylinder apparatus used by Day and Bleakney. All of the constants have been redetermined, and especial attention has been given to the corrections to the simple theory. The value obtained at 22°C is ?=1.8243±0.0045 c.g.s. units. This raises the oil drop value of e to 4.796 e.s.u. It is shown in the appendix that a correction must be applied for the opening between the suspended cylinder and the guard cylinders, and also a correction must be applied for the moment of inertia of the air carried around by the cylinder when determining its moment of inertia. Neglect of these corrections has introduced some additional uncertainty into other work.

W. V. Houston

1937-10-01T23:59:59.000Z

140

Bound on viscosity and the generalized second law of thermodynamics  

SciTech Connect (OSTI)

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.

Fouxon, Itzhak; Betschart, Gerold; Bekenstein, Jacob D. [Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem 91904 (Israel)

2008-01-15T23:59:59.000Z

Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Bound on viscosity and the generalized second law of thermodynamics  

Science Journals Connector (OSTI)

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.

Itzhak Fouxon; Gerold Betschart; Jacob D. Bekenstein

2008-01-10T23:59:59.000Z

142

Viscosity, Specific (for Suspensions and Solutions)  

Science Journals Connector (OSTI)

n The viscosity of a composition (?) minus the viscosity of the liquid (? o), divided by the viscosity of the liquid phase. The symbol is...? sp. (Kamide, K., and dobashi, T.,...

Jan W. Gooch

2011-01-01T23:59:59.000Z

143

Anomalous - viscosity current drive  

DOE Patents [OSTI]

An apparatus and method for maintaining a steady-state current in a toroidal magnetically confined plasma. An electric current is generated in an edge region at or near the outermost good magnetic surface of the toroidal plasma. The edge current is generated in a direction parallel to the flow of current in the main plasma and such that its current density is greater than the average density of the main plasma current. The current flow in the edge region is maintained in a direction parallel to the main current for a period of one or two of its characteristic decay times. Current from the edge region will penetrate radially into the plasma and augment the main plasma current through the mechanism of anomalous viscosity. In another aspect of the invention, current flow driven between a cathode and an anode is used to establish a start-up plasma current. The plasma-current channel is magnetically detached from the electrodes, leaving a plasma magnetically insulated from contact with any material obstructions including the cathode and anode.

Stix, Thomas H. (Princeton, NJ); Ono, Masayuki (Princeton Junction, NJ)

1988-01-01T23:59:59.000Z

144

Viscosity, relative (for suspensions and solutions)  

Science Journals Connector (OSTI)

n. The ratio between the viscosity of a composition (?), divided by the viscosity of the liquid phase (? 0). It is designated as ? rel.

2007-01-01T23:59:59.000Z

145

Viscosity of Gaseous HFC245fa  

Science Journals Connector (OSTI)

Viscosity of Gaseous HFC245fa ... The uncertainty of the reported viscosities was estimated to be within ± 2.0 % with a coverage factor of k = 2. ...

Xiaopo Wang; Jiangtao Wu; Zhigang Liu

2009-07-10T23:59:59.000Z

146

Viscosity Bound and Causality Violation  

Science Journals Connector (OSTI)

In recent work we showed that, for a class of conformal field theories (CFT) with Gauss-Bonnet gravity dual, the shear viscosity to entropy density ratio, ?/s, could violate the conjectured Kovtun-Starinets-Son viscosity bound, ?/s?1/4?. In this Letter we argue, in the context of the same model, that tuning ?/s below (16/25)(1/4?) induces microcausality violation in the CFT, rendering the theory inconsistent. This is a concrete example in which inconsistency of a theory and a lower bound on viscosity are correlated, supporting the idea of a possible universal lower bound on ?/s for all consistent theories.

Mauro Brigante; Hong Liu; Robert C. Myers; Stephen Shenker; Sho Yaida

2008-05-15T23:59:59.000Z

147

Bulk Viscosity, Decaying Dark Matter, and the Cosmic Acceleration  

E-Print Network [OSTI]

We discuss a cosmology in which cold dark-matter particles decay into relativistic particles. We argue that such decays could lead naturally to a bulk viscosity in the cosmic fluid. For decay lifetimes comparable to the present hubble age, this bulk viscosity enters the cosmic energy equation as an effective negative pressure. We investigate whether this negative pressure is of sufficient magnitude to account fo the observed cosmic acceleration. We show that a single decaying species in a flat, dark-matter dominated cosmology without a cosmological constant cannot reproduce the observed magnitude-redshift relation from Type Ia supernovae. However, a delayed bulk viscosity, possibly due to a cascade of decaying particles may be able to account for a significant fraction of the apparent cosmic acceleration. Possible candidate nonrelativistic particles for this scenario include sterile neutrinos or gauge-mediated decaying supersymmetric particles.

James R. Wilson; Grant J. Mathews; George M. Fuller

2006-09-25T23:59:59.000Z

148

The Viscosity of Liquid Helium  

Science Journals Connector (OSTI)

2 September 1935 research-article The Viscosity of Liquid Helium J. O. Wilhelm A. D. Misener A. R. Clark The Royal Society is collaborating with JSTOR to digitize, preserve...

1935-01-01T23:59:59.000Z

149

The Viscosity of the Blood  

Science Journals Connector (OSTI)

24 October 1906 research-article The Viscosity of the Blood A. Du Pre Denning John H. Watson The Royal Society is collaborating with JSTOR to digitize, preserve, and extend...

1906-01-01T23:59:59.000Z

150

Viscosity Measurements in Molten Glass  

Science Journals Connector (OSTI)

The relations existing between viscosity determinations and the various stages of glass manufacture are pointed out and explained with reference to a typical viscosity?temperature curve. The rotation viscometer employed in making such determinations is described. Curves are shown for four representative types of glasses: a lead a lime a lead borosilicate and a hard borosilicate and the use to which such comparison curves may be put is indicated.

Howard R. Lillie

1932-01-01T23:59:59.000Z

151

Viscosity/Concentration Relationships for Emulsions  

Science Journals Connector (OSTI)

Empirical and theoretical relationships are developed to describe the viscosity/concentration behavior of Newtonian and non?Newtonian emulsions having dispersed?phase concentrations less than 74% by volume. The developed equations are valid for both oil in water and water in oil types of emulsions.Emulsions exhibiting electroviscous effect (increase in viscosity due to presence of electric charge on the surface of droplets) could also be described adequately by these equations. The proposed equations have the ability to predict the emulsionviscosity as a function of dispersed?phase concentration and shear rate if the flow curve (shear stress versus shear rate plot) is known experimentally at a single value of the dispersed?phase concentration.

Rajinder Pal; Edward Rhodes

1989-01-01T23:59:59.000Z

152

Modeling of heat and mass transfer in a hydrocarbon fluid under inductive heating  

Science Journals Connector (OSTI)

Results of numerical simulations of the thermal action on a high-viscosity hydrocarbon fluid with temperature-dependent viscosity and thermal conductivity are presented. A system of equations of thermal convec...

L. A. Kovaleva; V. N. Kireev; A. A. Musin

2009-01-01T23:59:59.000Z

153

Shear viscosity in hybrid stars  

Science Journals Connector (OSTI)

A study of the shear viscosity of hadrons and quarks in hybrid stars has been performed in the framework of the microscopic transport theory. The neutron-star structure has been determined employing the equation of state from the Brueckner theory with three-body force for the hadron phase, and the equation of state from the MIT bag model for the deconfined quark phase. The nucleon-nucleon cross sections in dense matter have been consistently calculated from the Brueckner G matrix, whereas for the quark-quark cross sections the perturbative QCD has been adopted. Despite that the quark contribution to the shear viscosity is quite small at low temperature, the transition to the deconfined phase makes the equation of state much softer with the result that the baryon viscosity turns out to be enhanced instead of reduced in hybrid stars. The damping time scale of r-modes due to the shear viscosity has been evaluated for several stable configurations of a hybrid star and compared with the neutron-star spin-down time scale induced by the emission gravitation radiation from the r-modes. The enhancement of the total viscosity makes the viscosity time scale comparable with the gravitation radiation one at low temperature.

D. Jaccarino; S. Plumari; V. Greco; U. Lombardo; A. B. Santra

2012-05-03T23:59:59.000Z

154

A new type of whole oil-based drilling fluid  

Science Journals Connector (OSTI)

Abstract To meet the demand of ultra-deep well drilling and shale gas well drilling, organic clay and a oil-based filtrate reducer were developed and a whole oil-based drilling fluid formula was optimized. The performance of organic clay, oil-based filtrate reducer and the whole oil-based drilling fluid were evaluated in laboratory, and the whole oil-based drilling fluid was applied in drilling process for further test of its performance. Long carbon chain quaternary ammonium salt was used as modifying agents when synthesizing organobentonites. Oil-based filtrate reducer was synthesized with monomers of lignite and amine class. The laboratory tests show that the organic clay can effectively increase the viscosity of oil-based drilling fluid and the oil-based filtrate reducer can reduce the fluid loss. Their performances were better than additives of the same kind at home and abroad. The organic clay and oil-based filtrate reducer had great compatibility with the other additives in oil-based drilling fluid. Based on the optimal additives addition amount tests, the whole oil-based drilling fluid formula was determined and the test results show that the performances of the whole oil-based drilling fluids with various densities were great. The laboratory tests show that the oil-based drilling fluid developed was high temperature resistant, even at 200 °C, as density varies from 0.90 to 2.0 g/cm3, it still held good performance with only a little fluid loss, good inhibition, great anti-pollution, and good reservoir protection performance. Field application result shows that the performance of the oil-based drilling fluid is stable with great ability to maintain wellbore stability and lower density than the water-based drilling fluid; drilling bits can be used much longer and the average penetration rate is increased; the oil-based drilling fluid can satisfy the drilling requirements.

Jiancheng LI; Peng YANG; Jian GUAN; Yande SUN; Xubing KUANG; Shasha CHEN

2014-01-01T23:59:59.000Z

155

Singularity and entropy of the viscosity dark energy model  

E-Print Network [OSTI]

In this paper bulk viscosity is introduced to describe the effects of cosmic non-perfect fluid on the cosmos evolution and to build the unified dark energy (DE) with (dark) matter models. Also we derive a general relation between the bulk viscosity form and Hubble parameter that can provide a procedure for the viscosity DE model building. Especially, a redshift dependent viscosity parameter $\\zeta\\propto\\lambda_{0}+\\lambda_{1}(1+z)^{n}$ proposed in the previous work by X.H.Meng and X.Dou in 2009\\cite{md} is investigated extensively in this present work. Further more we use the recently released supernova dataset (the Constitution dataset) to constrain the model parameters. In order to differentiate the proposed concrete dark energy models from the well known $\\Lambda$CDM model, statefinder diagnostic method is applied to this bulk viscosity model, as a complementary to the $Om$ parameter diagnostic and the deceleration parameter analysis performed by us before. The DE model evolution behavior and tendency are...

Meng, X H

2009-01-01T23:59:59.000Z

156

Newtonian fluid flow through Microfabricated Hyperbolic Contractions  

E-Print Network [OSTI]

spraying (Barnes et al. 1989). Optimization of these processes requires accurate measurements for measurement of extensional viscosity involves studying the fluid flow through contractions profiled to give extensional viscosity. To remove the effect of shear at the walls of contractions Shaw (1975) proposed the use

157

Vanishing Viscosity Method for Transonic Flow  

E-Print Network [OSTI]

A vanishing viscosity method is formulated for two-dimensional transonic steady irrotational compressible fluid flows with adiabatic constant $\\gamma\\in [1,3)$. This formulation allows a family of invariant regions in the phase plane for the corresponding viscous problem, which implies an upper bound uniformly away from cavitation for the viscous approximate velocity fields. Mathematical entropy pairs are constructed through the Loewner-Morawetz relation by entropy generators governed by a generalized Tricomi equation of mixed elliptic-hyperbolic type, and the corresponding entropy dissipation measures are analyzed so that the viscous approximate solutions satisfy the compensated compactness framework. Then the method of compensated compactness is applied to show that a sequence of solutions to the artificial viscous problem, staying uniformly away from stagnation, converges to an entropy solution of the inviscid transonic flow problem.

Gui-Qiang Chen; Marshall Slemrod; Dehua Wang

2006-10-07T23:59:59.000Z

158

Regularity criteria and uniform estimates for the Boussinesq system with the temperature-dependent viscosity and thermal diffusivity  

E-Print Network [OSTI]

In this paper we establish some regularity criteria for the 3D Boussinesq system with the temperature-dependent viscosity and thermal diffusivity. We also obtain some uniform estimates for the corresponding 2D case when the fluid viscosity coefficient is a positive constant.

Jishan Fan; Fucai Li; Gen Nakamura

2012-10-09T23:59:59.000Z

159

Viscosity in X-ray clusters: Braginskii over 5  

E-Print Network [OSTI]

We argue that it is currently impossible to simulate X-ray clusters using correct equations, because even the MHD description is not applicable. But since fluid simulations actually reproduce observations quite well, one may try to improve the fluid codes by including molecular transport of heat and momentum. We calculate the effective molecular viscosity for the simplest model of magnetic field and obtain 1/5 of the Braginskii value, similar to 1/3 of Spitzer for the heat conduction. This is large enough to noticeably damp the X-ray cluster turbulence.

A. Gruzinov

2006-11-07T23:59:59.000Z

160

Bulk viscosity in hybrid stars  

Science Journals Connector (OSTI)

We compute the bulk viscosity of a mixed quark-hadron phase. In the first scenario to be discussed, the mixed phase occurs at large densities and we assume that it is composed of a mixing of hyperonic matter and quarks in the Color Flavor Locked phase. In a second scenario, the mixed phase occurs at lower densities and it is composed of a mixing of nucleons and unpaired quark matter. We have also investigated the effect of a nonvanishing surface tension at the interface between hadronic and quark matter. In both scenarios, the bulk viscosity is large when the surface tension is absent, while the value of the viscosity reduces in the second scenario when a finite value for the surface tension is taken into account. In all cases, the r-mode instabilities of the corresponding hybrid star are suppressed.

A. Drago; A. Lavagno; G. Pagliara

2005-05-16T23:59:59.000Z

Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Suprathermal viscosity of dense matter  

SciTech Connect (OSTI)

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 {mu}{sub {Delta}} of the chemical potentials from chemical equilibrium fulfills {mu}{sub {Delta}} > 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.

Alford, Mark; Mahmoodifar, Simin; Schwenzer, Kai [Department of Physics, Washington University in St. Louis, Missouri, 63130 (United States)

2010-12-22T23:59:59.000Z

162

Viscosity Bound and Causality Violation  

SciTech Connect (OSTI)

In recent work we showed that, for a class of conformal field theories (CFT) with Gauss-Bonnet gravity dual, the shear viscosity to entropy density ratio, {eta}/s, could violate the conjectured Kovtun-Starinets-Son viscosity bound, {eta}/s{>=}1/4{pi}. In this Letter we argue, in the context of the same model, that tuning {eta}/s below (16/25)(1/4{pi}) induces microcausality violation in the CFT, rendering the theory inconsistent. This is a concrete example in which inconsistency of a theory and a lower bound on viscosity are correlated, supporting the idea of a possible universal lower bound on {eta}/s for all consistent theories.

Brigante, Mauro; Liu, Hong [Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Myers, Robert C. [Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5 (Canada); Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Shenker, Stephen; Yaida, Sho [Department of Physics, Stanford University, Stanford, California 94305 (United States)

2008-05-16T23:59:59.000Z

163

Shear Viscosity of Quark Matter  

E-Print Network [OSTI]

We consider the shear viscosity of a system of quarks and its ratio to the entropy density above the critical temperature for deconfinement. Both quantities are derived and computed for different modeling of the quark self-energy, also allowing for a temperature dependence of the effective mass and width. The behaviour of the viscosity and the entropy density is argued in terms of the strength of the coupling and of the main characteristics of the quark self-energy. A comparison with existing results is also discussed.

W. M. Alberico; S. Chiacchiera; H. Hansen; A. Molinari; M. Nardi

2007-07-30T23:59:59.000Z

164

Bulk Viscosity of Interacting Hadrons  

E-Print Network [OSTI]

We show that first approximations to the bulk viscosity $\\eta_v$ are expressible in terms of factors that depend on the sound speed $v_s$, the enthalpy, and the interaction (elastic and inelastic) cross section. The explicit dependence of $\\eta_v$ on the factor $(\\frac 13 - v_s^2)$ is demonstrated in the Chapman-Enskog approximation as well as the variational and relaxation time approaches. The interesting feature of bulk viscosity is that the dominant contributions at a given temperature arise from particles which are neither extremely nonrelativistic nor extremely relativistic. Numerical results for a model binary mixture are reported.

A. Wiranata; M. Prakash

2009-06-30T23:59:59.000Z

165

Fundamentals of Engineering (FE) Exam Fluid Mechanics Review  

E-Print Network [OSTI]

one unit area layer of a substance over another � Viscosity (�): measure of a fluid's resistance Energy, Friction Loss, and Pipe Flow Momentum and Drag #12;Pressure � Gage pressure: measured relative Engineering March 22, 2013 #12;Morning (Fluid Mechanics) A. Flow measurement B. Fluid properties C. Fluid

Provancher, William

166

"Nanotechnology Enabled Advanced Industrial Heat Transfer Fluids"  

SciTech Connect (OSTI)

ABSTRACT Nanotechnology Enabled Advanced industrial Heat Transfer Fluids” Improving the efficiency of Industrial Heat Exchangers offers a great opportunity to improve overall process efficiencies in diverse industries such as pharmaceutical, materials manufacturing and food processing. The higher efficiencies can come in part from improved heat transfer during both cooling and heating of the material being processed. Additionally, there is great interest in enhancing the performance and reducing the weight of heat exchangers used in automotives in order to increase fuel efficiency. The goal of the Phase I program was to develop nanoparticle containing heat transfer fluids (e.g., antifreeze, water, silicone and hydrocarbon-based oils) that are used in transportation and in the chemical industry for heating, cooling and recovering waste heat. Much work has been done to date at investigating the potential use of nanoparticle-enhanced thermal fluids to improve heat transfer in heat exchangers. In most cases the effect in a commercial heat transfer fluid has been marginal at best. In the Phase I work, we demonstrated that the thermal conductivity, and hence heat transfer, of a fluid containing nanoparticles can be dramatically increased when subjected to an external influence. The increase in thermal conductivity was significantly larger than what is predicted by commonly used thermal models for two-phase materials. Additionally, the surface of the nanoparticles was engineered so as to have a minimal influence on the viscosity of the fluid. As a result, a nanoparticle-laden fluid was successfully developed that can lead to enhanced heat transfer in both industrial and automotive heat exchangers

Dr. Ganesh Skandan; Dr. Amit Singhal; Mr. Kenneth Eberts; Mr. Damian Sobrevilla; Prof. Jerry Shan; Stephen Tse; Toby Rossmann

2008-06-12T23:59:59.000Z

167

Bulk viscosity and deflationary universes  

E-Print Network [OSTI]

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

J. A. S. Lima; R. Portugal; I. Waga

2007-08-24T23:59:59.000Z

168

The Viscosity of Compressed Gases  

Science Journals Connector (OSTI)

New data and a new theory for the viscosity of compressed gases are presented. Data for nitrogen, hydrogen and a mixture of these gases are given, in the calculation of which, the "end effects" are not neglected as has been done in the past. Previous viscosity data are of doubtful validity owing to neglect of this factor. The theory is based on an analogy between the kinetic pressure and viscosity of a gas and is derived using an equation of state of the Lorentz type. Allowance is made for the difference between the viscosity and compressibility covolumes. The theory is substantiated experimentally and further confirmed by the recalculation of other data on the variation of Reynolds' criterion with the pressure, which is here shown to be constant. The mixture data offer a direct opportunity of comparing the Lorentz and linear rules for the calculation of the covolume of a mixture from the covolumes of the components and such comparison indicates that the Lorentz rule is not to be preferred. The substantiation of the new theory is the first direct proof of the validity of the separate treatment of the kinetic and cohesive pressures in the equation of state.

James H. Boyd; Jr.

1930-05-15T23:59:59.000Z

169

Kinematic Viscosity of Helium II  

Science Journals Connector (OSTI)

By observing the time of formation of the meniscus in a cylindrical vessel suddenly given a rotation, it has been found possible to determine, directly, the kinematic viscosity of both He I and He II. At the angular velocities used (?15 rev/sec) it appears that, for He II, all the liquid rotates rather than the normal component alone.

R. J. Donnelly; G. V. Chester; R. H. Walmsley; C. T. Lane

1956-04-01T23:59:59.000Z

170

Anomalous-viscosity current drive  

DOE Patents [OSTI]

The present invention relates to a method and apparatus for maintaining a steady-state current for magnetically confining the plasma in a toroidal magnetic confinement device using anomalous viscosity current drive. A second aspect of this invention relates to an apparatus and method for the start-up of a magnetically confined toroidal plasma.

Stix, T.H.; Ono, M.

1986-04-25T23:59:59.000Z

171

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS Int. J. Numer. Meth. Fluids (2012)  

E-Print Network [OSTI]

are still within reasonable range. Nevertheless, for test case two, which has higher density and viscosity, emulsification, spraying and so on. The kinematics and dynamics of the fluid interfaces play an important role

Frey, Pascal

172

Photoinduced aging and viscosity evolution in Se-rich Ge-Se glasses  

SciTech Connect (OSTI)

We propose here to investigate the non-equilibrium viscosity of Ge-Se glasses under and after light irradiation. Ge{sub 10}Se{sub 90} and Ge{sub 20}Se{sub 80} fibers have been aged in the dark and under ambient light, over months. During aging, both the relaxation of enthalpy and the viscosity have been investigated. The viscosity was measured by shear relaxation-recovery tests allowing the measurement of non-equilibrium viscosity. When Ge{sub 10}Se{sub 90} glass fibers are aged under irradiation, a relatively fast fictive temperature decrease is observed. Concomitantly, during aging under irradiation, the non-equilibrium viscosity increases and reaches an equilibrium after two months of aging. This viscosity increase is also observed in Ge{sub 20}Se{sub 80} fibers. Nevertheless, this equilibrium viscosity is far below the viscosity expected at the configurational equilibrium. As soon as the irradiation ceases, the viscosity increases almost instantaneously by about one order of magnitude. Then, if the fibers are kept in the dark, their viscosity slowly increases over months. The analysis of the shear relaxation functions shows that the aging is thermorheologically simple. On the other side, there is no simple relaxation between the shear relaxation functions measured under irradiation and those measured in the dark. These results clearly suggest that a very specific photoinduced aging process occurs under irradiation. This aging is due to photorelaxation. Nevertheless, the viscosity changes are not solely correlated to photoaging and photorelaxation. A scenario is proposed to explain all the observed viscosity evolutions under and after irradiation, on the basis of photoinduced transient defects.

Gueguen, Yann; Sangleboeuf, Jean-Christophe; Rouxel, Tanguy [LARMAUR ERL CNRS 6274, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex (France)] [LARMAUR ERL CNRS 6274, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex (France); King, Ellyn A.; Lucas, Pierre [Department of Materials Science and Engineering, University of Arizona, 4715 E. Fort Lowell Road, Tucson, Arizona 85712 (United States)] [Department of Materials Science and Engineering, University of Arizona, 4715 E. Fort Lowell Road, Tucson, Arizona 85712 (United States); Keryvin, Vincent [LIMATB EA 4250, Université de Bretagne Sud, Rue de Saint Maudé, 56321 Lorient Cedex (France)] [LIMATB EA 4250, Université de Bretagne Sud, Rue de Saint Maudé, 56321 Lorient Cedex (France); Bureau, Bruno [Equipe Verres et Céramiques, UMR-CNRS 6226 Sciences Chimiques de Rennes, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex (France)] [Equipe Verres et Céramiques, UMR-CNRS 6226 Sciences Chimiques de Rennes, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex (France)

2013-08-21T23:59:59.000Z

173

Viscosity Increments of Non-Ionized Molecules  

Science Journals Connector (OSTI)

... DISTINCTIVE property of colloidally dispersed substances as opposed to crystalloids is their relatively higher intrinsic viscosity or ... or viscosity increment. The reason for this is that the medium in which the macromolecular particles ...

ALFRED POLSON

1960-08-06T23:59:59.000Z

174

Viscosity model for gases in the transition regime  

Science Journals Connector (OSTI)

We have studied a model of tangential viscosity of a fluid in which high-order spatial derivatives of the velocity are taken into account. The model indicates that for a gas in the transition regime, and within a range of boundary conditions, the tangential stress presents an oscillatory dependence on the density. An experiment designed to detect these oscillations was done with helium at constant temperature T=294°K and varying the pressure within the range 0.5-50 mTorr. The results were found to be in good agreement with the oscillations predicted by our model when the spatial derivative of the fluid velocity near the boundaries was close to zero. From the separation in density between these oscillations, it is possible to obtain an independent measurement of the atomic mean cross section for helium. This method makes specific use of the way the viscosity oscillates with the density in the transition regime instead of using the value that the viscosity takes in the continuous regime. The good agreement between our measurements of the cross section and the values that have been obtained by other methods gives an indication of the validity of the proposed model.

D. Moronta and M. García-Sucre

1978-08-01T23:59:59.000Z

175

Can dark energy viscosity be detected with the Euclid survey?  

Science Journals Connector (OSTI)

Recent work has demonstrated that it is important to constrain the dynamics of cosmological perturbations, in addition to the evolution of the background, if we want to distinguish among different models of the dark sector. Especially the anisotropic stress of the (possibly effective) dark energy fluid has been shown to be an important discriminator between modified gravity and dark energy models. In this paper we use approximate analytical solutions of the perturbation equations in the presence of viscosity to study how the anisotropic stress affects the weak lensing and galaxy power spectrum. We then forecast how sensitive the photometric and spectroscopic Euclid surveys will be to both the speed of sound and the viscosity of our effective dark energy fluid when using weak lensing tomography and the galaxy power spectrum. We find that Euclid alone can only constrain models with a very small speed of sound and viscosity, while it will need the help of other observables in order to give interesting constraints on models with a sound speed close to one. This conclusion is also supported by the expected Bayes factor between models.

Domenico Sapone; Elisabetta Majerotto; Martin Kunz; Bianca Garilli

2013-08-05T23:59:59.000Z

176

Can dark energy viscosity be detected with the Euclid survey?  

E-Print Network [OSTI]

Recent work has demonstrated that it is important to constrain the dynamics of cosmological perturbations, in addition to the evolution of the background, if we want to distinguish among different models of the dark sector. Especially the anisotropic stress of the (possibly effective) dark energy fluid has been shown to be an important discriminator between modified gravity and dark energy models. In this paper we use approximate analytical solutions of the perturbation equations in the presence of viscosity to study how the anisotropic stress affects the weak lensing and galaxy power spectrum. We then forecast how sensitive the photometric and spectroscopic Euclid surveys will be to both the speed of sound and the viscosity of our effective dark energy fluid when using weak lensing tomography and the galaxy power spectrum. We find that Euclid alone can only constrain models with very small speed of sound and viscosity, while it will need the help of other observables in order to give interesting constraints on models with a sound speed close to one. This conclusion is also supported by the expected Bayes factor between models.

Domenico Sapone; Elisabetta Majerotto; Martin Kunz; Bianca Garilli

2013-05-08T23:59:59.000Z

177

Shear viscosity of the quark matter  

E-Print Network [OSTI]

We discuss shear viscosity of the quark matter by using Kubo formula. The shear viscosity is calculated in the framework of the quasi-particle RPA for the Nambu-Jona-Lasinio model. We obtain a formula that the shear viscosity is expressed by the quadratic form of the quark spectral function in the chiral symmetric phase. The magnitude of the shear viscosity is discussed assuming the Breit-Wigner type for the spectral function.

Masaharu Iwasaki; Hiromasa Ohnishi; Takahiko Fukutome

2007-03-26T23:59:59.000Z

178

Numerical Studies of Fluid Leakage from a Geologic Disposal Reservoir for CO2 Show Self-Limiting Feedback between Fluid Flow and Heat Transfer  

E-Print Network [OSTI]

Feedback between Fluid Flow and Heat Transfer Karsten Pruessfeedback between fluid flow and heat transfer tends to limitfluid mobility (viscosity and relative permeability effects), are countered by effects arising from limitations in the rate of conductive heat transfer.

Pruess, Karsten

2005-01-01T23:59:59.000Z

179

Ocean viscosity and climate M. Jochum,1  

E-Print Network [OSTI]

Ocean viscosity and climate M. Jochum,1 G. Danabasoglu,1 M. Holland,1 Y.-O. Kwon,1 and W. G. Large1] The impacts of parameterized lateral ocean viscosity on climate are explored using three 120-year integrations of a fully coupled climate model. Reducing viscosity leads to a generally improved ocean circulation

Jochum, Markus

180

VISCOSITY IN ACCRETION DISKS PAUL J. WIITA  

E-Print Network [OSTI]

VISCOSITY IN ACCRETION DISKS PAUL J. WIITA Department of Physics & Astronomy, Georgia State University Atlanta, Georgia, USA Abstract. Various proposals and prescriptions for the viscosity in accretion a solution to this difficult problem. 1. Introduction The nature of the viscosity within accretion disks

Wiita, Paul J.

Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Viscosity profile of the lower mantle  

Science Journals Connector (OSTI)

......October 1985 research-article Articles Viscosity profile of the lower mantle Kirk Ellsworth...determine the variation of effective viscosity across the lower mantle from models of...consistent with recent estimates of mantle viscosity from post-glacial rebound and true......

Kirk Ellsworth; Gerald Schubert; Charles G. Sammis

1985-10-01T23:59:59.000Z

182

Viscosity and the Structure of Molten Silicates  

Science Journals Connector (OSTI)

7 December 1954 research-article Viscosity and the Structure of Molten Silicates...devised which enables measurements of the viscosity of liquids to be made at maximum temperatures...instrument has been applied to measure the viscosity of the system CaO-SiO over the composition...

1954-01-01T23:59:59.000Z

183

Falsification of dark energy by fluid mechanics  

E-Print Network [OSTI]

The 2011 Nobel Prize in Physics was awarded for the discovery of accelerating supernovae dimness, suggesting a remarkable change in the expansion rate of the Universe from a decrease since the big bang to an increase, driven by anti-gravity forces of a mysterious dark energy material comprising 70% of the Universe mass-energy. Fluid mechanical considerations falsify both the accelerating expansion and dark energy concepts. Kinematic viscosity is neglected in current standard models of self-gravitational structure formation, which rely on cold dark matter CDM condensations and clusterings that are also falsified by fluid mechanics. Weakly collisional CDM particles do not condense but diffuse away. Photon viscosity predicts superclustervoid fragmentation early in the plasma epoch and protogalaxies at the end. At the plasma-gas transition, the plasma fragments into Earth-mass gas planets in trillion planet clumps (proto-globular-star-cluster PGCs). The hydrogen planets freeze to form the dark matter of galaxies and merge to form their stars. Dark energy is a systematic dimming error for Supernovae Ia caused by dark matter planets near hot white dwarf stars at the Chandrasekhar carbon limit. Evaporated planet atmospheres may or may not scatter light from the events depending on the line of sight.

Carl H. Gibson

2012-03-23T23:59:59.000Z

184

Project Title: VIscosity Reduction Date:  

Broader source: Energy.gov (indexed) [DOE]

4t 3 4t 3 l I Project lnfonnatlon Project Title: VIscosity Reduction Date: 11-22-2010 DOE Code: 673()-()20-51141 Contractor Code: 8067-778 Project Lead: Frank Ingham Project Overview 1. The purpose of the project is to test a tool that temporarily reduces the viscosity of oil which allows it to be 1. Brief project description ~nclude pumped through pipelines easier. The test will require about 4 miles of line to pump the oil through after anything that could impact the treatment (hence the need to connect the 31oops together), a holding volume for recovery, then repeat. environmenJ] There will be tanks to hold the original volume, tanks to receive the volume after treatment and pumping 2. Legal location through the line, possible transfer between tanks, transport (trucking) of the oil to the site (by the COC) and

185

Viscosity of Liquid He II  

Science Journals Connector (OSTI)

The viscosity of liquid He4 has been measured between 1.10°K and the lambda point. A new type of viscometer was used, based on the damping of the transverse vibrations of a fine wire stretched between two rigid supports. The simplicity of the hydrodynamic problem and the low nuisance damping of the wire make this technique particularly appropriate for the measurement of small viscosities. The smoothed data are presented and found to be in good agreement with the latest rotating cylinder viscometer results. In different experimental runs the vibration frequency was varied by a factor of seven and the wire diameter by a factor of three. There was no evidence of systematic trend due to mean free-path effects or geometrical corrections.

J. T. Tough; W. D. McCormick; J. G. Dash

1963-12-15T23:59:59.000Z

186

Under consideration for publication in J. Fluid Mech. 1 Dynamics of Bead Formation,  

E-Print Network [OSTI]

evolution it is possible to extract transient extensional viscosity information even for very low viscosity the instability and breakup of polymeric jets is important for a wide variety of applications including spraying- stable when compared to a Newtonian fluid of the same viscosity and inertia (Middleman (1965), Goldin et

187

Bulk Viscosity of a Gas of Massless Pions  

E-Print Network [OSTI]

In the hadronic phase, the dominant configuration of QCD with two flavors of massless quarks is a gas of massless pions. We calculate the bulk viscosity (zeta) using the Boltzmann equation with the kinetic theory generalized to incorporate the trace anomaly. We find that the dimensionless ratio zeta/s, s being the entropy density, is monotonic increasing below T=120 MeV, where chiral perturbation theory is applicable. This, combined with previous results, shows that zeta/s reaches its maximum near the phase transition temperature Tc, while eta/s, eta being the shear viscosity, reaches its minimum near Tc in QCD with massless quarks.

Jiunn-Wei Chen; Juven Wang

2007-11-30T23:59:59.000Z

188

From Stopping to Viscosity in Heavy Ion Collisions  

SciTech Connect (OSTI)

Stopping in heavy ion collisions is investigated with the aim of learning about the shear viscosity of nuclear matter. Boltzmann equation simulations are compared to available data on stopping in the energy range of 20-117 MeV/nucleon. Stopping observables used include momentum anisotropy and linear momentum transfer. The data show that modeling the transport with free nucleon-nucleon cross-sections is inaccurate and reduced cross-sections are required. Reduction of the cross-sections produces an increase in the shear viscosity of nuclear matter, compared to calculations based on free cross-sections.

Barker, Brent W.; Danielewicz, Pawel [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States)

2010-04-26T23:59:59.000Z

189

Predicting human blood viscosity in silico  

SciTech Connect (OSTI)

Cellular suspensions such as blood are a part of living organisms and their rheological and ?ow characteristics determine and affect majority of vital functions. The rheological and ?ow properties of cell suspensions are determined by collective dynamics of cells, their structure or arrangement, cell properties and interactions. We study these relations for blood in silico using a mesoscopic particle-based method and two different models (multi-scale/low-dimensional) of red blood cells. The models yield accurate quantitative predictions of the dependence of blood viscosity on shear rate and hematocrit. We explicitly model cell aggregation interactions and demonstrate the formation of reversible rouleaux structures resulting in a tremendous increase of blood viscosity at low shear rates and yield stress, in agreement with experiments. The non-Newtonian behavior of such cell suspensions (e.g., shear thinning, yield stress) is analyzed and related to the suspension’s microstructure, deformation and dynamics of single cells. We provide the ?rst quantitative estimates of normal stress differences and magnitude of aggregation forces in blood. Finally, the ?exibility of the cell models allows them to be employed for quantitative analysis of a much wider class of complex ?uids including cell, capsule, and vesicle suspensions.

Fedosov, Dmitry A.; Pan, Wenxiao; Caswell, Bruce; Gompper, Gerhard; Karniadakis, George E.

2011-07-19T23:59:59.000Z

190

Stress tensor and bulk viscosity in relativistic nuclear collisions  

E-Print Network [OSTI]

We discuss the influence of different initial conditions for the stress tensor and the effect of bulk viscosity on the expansion and cooling of the fireball created in relativistic heavy ion collisions. In particular, we explore the evolution...however, it does not significantly increase the entropy produced....

Fries, Rainer J.; Mueller, Berndt; Schaefer, Andreas.

2008-01-01T23:59:59.000Z

191

Viscosity in cosmological simulations of clusters of galaxies  

E-Print Network [OSTI]

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

M. Brüggen; M. Ruszkowski

2005-12-06T23:59:59.000Z

192

Varying properties of in situ heat treatment of a tar sands formation based on assessed viscosities  

DOE Patents [OSTI]

A method for treating a tar sands formation includes providing heat to at least part of a hydrocarbon layer in the formation from a plurality of heaters located in the formation. The heat is allowed to transfer from the heaters to at least a portion of the formation. A viscosity of one or more zones of the hydrocarbon layer is assessed. The heating rates in the zones are varied based on the assessed viscosities. The heating rate in a first zone of the formation is greater than the heating rate in a second zone of the formation if the viscosity in the first zone is greater than the viscosity in the second zone. Fluids are produced from the formation through the production wells.

Karanikas, John Michael; Vinegar, Harold J

2014-03-04T23:59:59.000Z

193

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

E-Print Network [OSTI]

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

J. Noronha-Hostler; J. Noronha; F. Grassi

2014-06-12T23:59:59.000Z

194

Sweeping has no effect on renormalized turbulent viscosity  

E-Print Network [OSTI]

We employ renormalization group techniques (RG) to the Navier-Stokes equation in the presence of constant mean velocity field $\\mathbf U_0$, and show that the renormalized viscosity is independent of $\\mathbf U_0$. Thus we demonstrates that the renormalized parameter in Eulerian field theory is Galilean invariant, and it is unaffected by the "sweeping effect", contrary to the results of Kraichnan [Phys. Fluids {\\bf 7}, 1723 (1964)] on random Galilean invariance. Using direct numerical simulation, we show that the correlation functions for $\\mathbf U_0 =0$ and $\\mathbf U_0 \

Mahendra K. Verma; Abhishek Kumar

2014-11-11T23:59:59.000Z

195

Sweeping has no effect on renormalized turbulent viscosity  

E-Print Network [OSTI]

We employ renormalization group techniques (RG) to the Navier-Stokes equation in the presence of constant mean velocity field $\\mathbf U_0$, and show that the renormalized viscosity is independent of $\\mathbf U_0$. Thus we demonstrates that the renormalized parameter in Eulerian field theory is Galilean invariant, and it is unaffected by the "sweeping effect", contrary to the results of Kraichnan [Phys. Fluids {\\bf 7}, 1723 (1964)] on random Galilean invariance. Using direct numerical simulation, we show that the correlation functions for $\\mathbf U_0 =0$ and $\\mathbf U_0 \

Verma, Mahendra K

2014-01-01T23:59:59.000Z

196

Holographic Viscosity of Fundamental Matter  

E-Print Network [OSTI]

A holographic dual of a finite-temperature SU(N_c) gauge theory with a small number of flavours N_f viscosity to entropy ratio in these theories saturates the conjectured universal bound eta/s >= 1/4\\pi. The contribution of the fundamental matter eta_fund is therefore enhanced at strong 't Hooft coupling lambda; for example, eta_fund ~ lambda N_c N_f T^3 in four dimensions. Other transport coefficients are analogously enhanced. These results hold with or without a baryon number chemical potential.

David Mateos; Robert C. Myers; Rowan M. Thomson

2006-10-16T23:59:59.000Z

197

Effective viscosity of microswimmer suspensions  

E-Print Network [OSTI]

The measurement of a quantitative and macroscopic parameter to estimate the global motility of a large population of swimming biological cells is a challenge Experiments on the rheology of active suspensions have been performed. Effective viscosity of sheared suspensions of live unicellular motile micro-algae (\\textit{Chlamydomonas Reinhardtii}) is far greater than for suspensions containing the same volume fraction of dead cells and suspensions show shear thinning behaviour. We relate these macroscopic measurements to the orientation of individual swimming cells under flow and discuss our results in the light of several existing models.

Salima Rafai; Levan Jibuti; Philippe Peyla

2009-09-23T23:59:59.000Z

198

Numerical Analysis of Cell Deformation of Twophase Flow with Discontinuous Viscosity and Nonlinear Surface Tension  

E-Print Network [OSTI]

­linear Surface Tension Zhilin Li and Sharon Lubkin Center For Research in Scientific Computation & Department equations, cell deformation, non­linear surface tension, jump conditions, interface, discontinuous and non boundary separating two fluids that have equal or different viscosity and non­linear surface tension

199

Viscosity bound violation in higher derivative gravity  

SciTech Connect (OSTI)

Motivated by the vast string landscape, we consider the shear viscosity to entropy density ratio in conformal field theories dual to Einstein gravity with curvature square corrections. After field redefinitions these theories reduce to Gauss-Bonnet gravity, which has special properties that allow us to compute the shear viscosity nonperturbatively in the Gauss-Bonnet coupling. By tuning of the coupling, the value of the shear viscosity to entropy density ratio can be adjusted to any positive value from infinity down to zero, thus violating the conjectured viscosity bound. At linear order in the coupling, we also check consistency of four different methods to calculate the shear viscosity, and we find that all of them agree. We search for possible pathologies associated with this class of theories violating the viscosity bound.

Brigante, Mauro; Liu Hong; Myers, Robert C.; Shenker, Stephen; Yaida, Sho [Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5 (Canada) and Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Department of Physics, Stanford University, Stanford, CA 94305 (United States)

2008-06-15T23:59:59.000Z

200

Viscosity of surfactant stabilized emulsions  

Science Journals Connector (OSTI)

A new scaling parameter for the viscosity of surfactant stabilized emulsions is proposed. We suggest that the attractive force between emulsiondroplets is caused by the small surfactantmicelles in the continuous phase of an emulsion. The new scaling parameter will be referred to as the depletion flow number Fl d =4?? s ??a 2 a m /kT? m and is defined as the ratio between the viscous energy needed to separate the droplets and the depletion energy that opposes this separation. Here ? s a a m and ? m are the solventviscosity dispersed phase droplet radius micelle radius and micelle volume fraction respectively. Fl d is of the order of unity at the onset of shear thinning and is capable of explaining all previously observed effects of drop size solventviscosity and surfactant concentration. With master curves which are obtained by using Fl d as the running parameter a relatively simple empirical model is constructed which can reproduce the viscosity curves of many previously reported in the literature.

K. M. B. Jansen; W. G. M. Agterof; J. Mellema

2001-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Bulk viscosity of a pion gas  

Science Journals Connector (OSTI)

We compute the bulk viscosity of a gas of pions at temperatures below the QCD crossover temperature, for the physical value of m?, to lowest order in chiral perturbation theory. Bulk viscosity is controlled by number-changing processes which become exponentially slow at low temperatures when the pions become exponentially dilute, leading to an exponentially large bulk viscosity ?~(F08/m?5)exp(2m?/T), where F0?93?MeV is the pion decay constant.

Egang Lu and Guy D. Moore

2011-04-07T23:59:59.000Z

202

Effect of Viscosity on the Microformability of Bulk Amorphous Alloy in Supercooled Liquid Region  

SciTech Connect (OSTI)

Previously published results have shown that viscosity greatly influences on the deformation behavior of the bulk amorphous alloy in supercooled liquid region during microforming process. And viscosity is proved to be a component of the evaluation index which indicating microformability. Based on the fluid flow theory and assumptions, bulk amorphous alloy can be regarded as the viscous materials with a certain viscosity. It is helpful to understand how the viscosity plays an important role in viscous materials with various viscosities by numerical simulation on the process. Analysis is carried out by linear state equation in FEM with other three materials, water, lubricant oil and polymer melt, whose viscosities are different obviously. The depths of the materials flow into the U-shaped groove during the microimprinting process are compared in this paper. The result shows that the deformation is quite different when surface tension effect is not considered in the case. With the lowest viscosity, water can reach the bottom of micro groove in a very short time. Lubricant oil and polymer melt slower than it. Moreover bulk amorphous alloys in supercooled liquid state just flow into the groove slightly. Among the alloys of different systems including Pd-, Mg- and Zr-based alloy, Pd-based alloy ranks largest in the depth. Mg-based alloy is the second. And Zr-based alloy is the third. Further more the rank order of the viscosities of the alloys is Pd-, Mg- and Zr-based. It agrees well with the results of calculation. Therefore viscosity plays an important role in the microforming of the bulk amorphous alloy in the supercooled liquid state.

Cheng Ming; Zhang Shihong; Wang Ruixue [Institute of Metal Research, Chinese Academy of Sciences Shenyang 110016, Liaoning Province (China)

2010-06-15T23:59:59.000Z

203

Hall viscosity, spin density, and torsion  

E-Print Network [OSTI]

We investigate the relationship between Hall viscosity, spin density and response to geometric torsion. For the most general effective action for relativistic gapped systems, the presence of non-universal terms implies that there is no relationship between torsion response and Hall viscosity. We also consider free relativistic and non-relativistic microscopic actions and again verify the existence of analogous non-universal couplings. Explicit examples demonstrate that torsion response is unrelated to both Hall viscosity and spin density. We also argue that relativistic gapped theories must have vanishing Hall viscosity in Lorentz invariant vacuums.

Geracie, Michael; Roberts, Matthew M

2014-01-01T23:59:59.000Z

204

Hyperon bulk viscosity in strong magnetic fields  

SciTech Connect (OSTI)

We study the bulk viscosity of neutron star matter including {lambda} hyperons in the presence of quantizing magnetic fields. Relaxation time and bulk viscosity due to both the nonleptonic weak process involving {lambda} hyperons and direct Urca processes are calculated here. In the presence of a strong magnetic field of 10{sup 17} G, the hyperon bulk viscosity coefficient is reduced, whereas bulk viscosity coefficients due to direct Urca processes are enhanced compared with their field free cases when many Landau levels are populated by protons, electrons, and muons.

Sinha, Monika; Bandyopadhyay, Debades [Theory Division and Centre for Astroparticle Physics, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata-700064 (India)

2009-06-15T23:59:59.000Z

205

Bulk viscosity in kaon condensed matter  

E-Print Network [OSTI]

We investigate the effect of $K^-$ condensed matter on bulk viscosity and r-mode instability in neutron stars. The bulk viscosity coefficient due to the non-leptonic process $n \\rightleftharpoons p + K^-$ is studied here. In this connection, equations of state are constructed within the framework of relativistic field theoretical models where nucleon-nucleon and kaon-nucleon interactions are mediated by the exchange of scalar and vector mesons. We find that the bulk viscosity coefficient due to the non-leptonic weak process in the condensate is suppressed by several orders of magnitude. Consequently, kaon bulk viscosity may not damp the r-mode instability in neutron stars.

Debarati Chatterjee; Debades Bandyopadhyay

2007-02-09T23:59:59.000Z

206

Viscosity of liquid Fe at high pressure  

Science Journals Connector (OSTI)

Synchrotron x-ray radiography has been used to measure the viscosity of pure liquid Fe at high pressure and temperature in a large volume press. A probe sphere rising through liquid Fe at high pressure and temperature is imaged, in situ, allowing for the derivation of sample viscosity through a modified form of Stokes’ equation. The effect of pressure on viscosity is fit by the semi empirical framework for transport coefficients in liquid metals, providing experimental verification of constant viscosity at the pressure-dependent melting temperature of liquid Fe where no change in liquid structure occurs.

Michael D. Rutter; Richard A. Secco; Hongjian Liu; Takeyuki Uchida; Mark L. Rivers; Stephen R. Sutton; Yanbin Wang

2002-08-14T23:59:59.000Z

207

Viscosity of Liquid Sodium and Potassium  

Science Journals Connector (OSTI)

2 November 1936 research-article Viscosity of Liquid Sodium and Potassium Y. S. Chiong The Royal Society is collaborating with JSTOR to digitize, preserve, and extend...

1936-01-01T23:59:59.000Z

208

Viscosity of Di-isodecylphthalate: A Potential Standard of Moderate Viscosity  

Science Journals Connector (OSTI)

The paper reports our first measurements of the viscosity of di-isodecylphthalate, which is a candidate ... . At the same time it has a viscosity, which, at room temperature, is around ... ±1.5%, following calibr...

F. J. P. Caetano; J. M. N. A. Fareleira…

2004-09-01T23:59:59.000Z

209

Lattice Boltzmann model for compressible fluids  

Science Journals Connector (OSTI)

We formulate a lattice Boltzmann model which simulates compressible fluids. By choosing the parameters of the equilibrium distribution appropriately, we are able to select the sound speed (which may be set arbitrarily low), bulk viscosity, and kinematic viscosity. This model simulates compressible flows and can include shocks. With a proper rescaling and zero-sound speed, this model simulates Burgers’s equation. The viscosity determined by a Chapman-Enskog expansion compares well with that measured from simulations. We also compare the exact solutions of Burgers’s equation on the unit circle to solutions of our lattice Boltzmann model, again finding reasonable agreement.

F. J. Alexander; H. Chen; S. Chen; G. D. Doolen

1992-08-15T23:59:59.000Z

210

An Empirical Viscosity Model for Coal Slags  

SciTech Connect (OSTI)

Slags of low viscosity readily penetrate the refractory lining in slagging gasifiers, causing rapid and severe corrosion called spalling. In addition, a low-viscosity slag that flows down the gasifier wall forms a relatively thin layer of slag on the refractory surface, allowing the corrosive gases in the gasifier to participate in the chemical reactions between the refractory and the slag. In contrast, a slag viscosity of <25 Pa•s at 1400°C is necessary to minimize the possibility of plugging the slag tap. There is a need to predict and optimize slag viscosity so slagging gasifiers can operate continuously at temperatures ranging from 1300 to 1650°C. The approach adopted in this work was to statistically design and prepare simulated slags, measure the viscosity as a function of temperature, and develop a model to predict slag viscosity based on slag composition and temperature. Statistical design software was used to select compositions from a candidate set of all possible vertices that will optimally represent the composition space for 10 main components. A total of 21 slag compositions were generated, including 5 actual coal slag compositions. The Arrhenius equation was applied to measured viscosity versus temperature data of tested slags, and the Arrhenius coefficients (A and B in ln(vis) = A + B/T) were expressed as linear functions of the slag composition. The viscosity model was validated using 1) data splitting approach, and 2) viscosity/temperature data of selected slag compositions from the literature that were formulated and melted at Pacific Northwest National Laboratory. The capability of the model to predict the viscosity of coal slags was compared with the model developed by Browning et al. because this model can predict the viscosity of slags from coal ash better than the most commonly used empirical models found in the literature.

Matyas, Josef; Cooley, Scott K.; Sundaram, S. K.; Rodriguez, Carmen P.; Edmondson, Autumn B.; Arrigoni, Benjamin M.

2008-10-25T23:59:59.000Z

211

Scaling Laws for Convection with Temperature-dependent Viscosity and Grain-damage  

E-Print Network [OSTI]

Numerical experiments of convection with grain-damage are used to develop scaling laws for convective heat flow, mantle velocity, and plate velocity across the stagnant lid and plate-tectonic regimes. Three main cases are presented in order of increasing complexity: a simple case wherein viscosity is only dependent on grainsize, a case where viscosity depends on temperature and grainsize, and finally a case where viscosity is temperature and grainsize sensitive, and the grain-growth (or healing) is also temperature sensitive. In all cases, convection with grain-damage scales differently than Newtonian convection due to the effects of grain-damage. For the fully realistic case, numerical results show stagnant lid convection, fully mobilized convection that resembles the temperature-independent viscosity case, and partially mobile or transitional convection, depending on damage to healing ratio, Rayleigh number, and the activation energies for viscosity and healing. Applying our scaling laws for the fully reali...

Foley, Bradford J

2014-01-01T23:59:59.000Z

212

Static and dynamic shear viscosity of a single-layer complex plasma  

SciTech Connect (OSTI)

The static and dynamic (complex) shear viscosity of a single-layer dusty plasma is measured by applying, respectively, a stationary and a periodically modulated shear stress, induced by the light pressure of manipulating laser beams. Under static conditions we observe a decrease of the viscosity with increasing shear rate, the so-called shear-thinning behavior. Under oscillating shear both the magnitude and the ratio of the dissipative and elastic contributions to the complex viscosity show strong frequency dependence, as the system changes from viscous to elastic in nature with increasing excitation frequency. Accompanying molecular dynamics simulations explain and support the experimental observations.

Hartmann, Peter [Research Institute for Solid State Physics and Optics of the Hungarian Academy of Sciences, P.O.B. 49, H-1525 Budapest (Hungary); Center for Astrophysics, Space Physics and Engineering Research (CASPER), One Bear Place 97310, Baylor University, Waco, Texas 76798 (United States); Sandor, Mate Csaba; Kovacs, Aniko; Donko, Zoltan [Research Institute for Solid State Physics and Optics of the Hungarian Academy of Sciences, P.O.B. 49, H-1525 Budapest (Hungary)

2011-07-15T23:59:59.000Z

213

Effective viscosity of bacterial suspensions: a three-dimensional PDE model with stochastic torque.  

SciTech Connect (OSTI)

We present a PDE model for dilute suspensions of swimming bacteria in a three-dimensional Stokesian fluid. This model is used to calculate the statistically-stationary bulk deviatoric stress and effective viscosity of the suspension from the microscopic details of the interaction of an elongated body with the background flow. A bacterium is modeled as an impenetrable prolate spheroid with self-propulsion provided by a point force, which appears in the model as an inhomogeneous delta function in the PDE. The bacterium is also subject to a stochastic torque in order to model tumbling (random reorientation). Due to a bacterium's asymmetric shape, interactions with prescribed generic planar background flows, such as a pure straining or planar shear flow, cause the bacterium to preferentially align in certain directions. Due to the stochastic torque, the steady-state distribution of orientations is unique for a given background flow. Under this distribution of orientations, self-propulsion produces a reduction in the effective viscosity. For sufficiently weak background flows, the effect of self-propulsion on the effective viscosity dominates all other contributions, leading to an effective viscosity of the suspension that is lower than the viscosity of the ambient fluid. This is in qualitative agreement with recent experiments on suspensions of Bacillus subtilis.

Haines, B. M.; Aranson, I. S.; Berlyand, L.; Karpeev, D. A. (Mathematics and Computer Science); ( MSD); (Penn State Univ.)

2012-01-01T23:59:59.000Z

214

Shear viscosity of pion gas  

E-Print Network [OSTI]

Using chiral perturbation theory we investigate the QCD shear viscosity ($\\eta $) to entropy density ($s$) ratio below the deconfinement temperature ($\\sim 170$ MeV) with zero baryon number density. It is found that $\\eta /s$ of QCD is monotonically decreasing in temperature ($T$) and reaches 0.6 with estimated $\\sim 50%$ uncertainty at T=120 MeV. A naive extrapolation of the leading order result shows that $\\eta /s$ reaches the $1/4\\pi $ minimum bound proposed by Kovtun, Son, and Starinets using string theory methods at $T\\sim 210$ MeV. This suggests a phase transition or cross over might occur at $T\\lesssim 210$ MeV in order for the bound to remain valid. Also, it is natural for $\\eta /s$ to stay close to the minimum bound around the phase transition temperature as was recently found in heavy ion collisions.

Eiji Nakano

2006-12-20T23:59:59.000Z

215

The viscosity of polymer melts  

Science Journals Connector (OSTI)

A simple theoretical argument is presented that gives the scaling behavior of the relaxation time in a polymer melt as a function of molecular weight M. The framework for this theory is based on the reptation model of de Gennes but also incorporates the effects of excluded volume. It is argued that the effects of excluded volume change the relaxation time from M 3 to M 3 exp(const×M 2/3). This argument agrees qualitatively with a direct simulation of the reptation model that incorporates many?chain excluded volume interactions. This simulation fits experimental data quite well giving an effective power law relationship between viscosity ? and molecular weight namely ??M 3.4±.1.

J. M. Deutsch

1986-01-01T23:59:59.000Z

216

Brief introduction to viscosity in hadron physics  

SciTech Connect (OSTI)

We introduce the concept of viscosity (both shear and bulk) in the context of hadron physics and in particular the meson gas, highlighting the current theoretical efforts to connect possible measurements of the viscosities to underlying physics such as a phase transition or the trace anomaly.

Dobado, Antonio; Llanes-Estrada, Felipe J.; Torres-Rincon, Juan M. [Departamento de Fisica Teorica I, Universidad Complutense de Madrid, 28040 Madrid (Spain)

2010-12-28T23:59:59.000Z

217

Viscosity Determination by Means of Ultrasonics  

Science Journals Connector (OSTI)

It has been shown that the phenomenon of persistence of diffracted lines in water suspensions of starch at different temperatures and also in water solutions of sucrose at different concentrations and constant temperature is related to the viscosity coefficient of the medium in terms of diffusion theory. Therefore we propose a method for the determination of viscosity coefficients by means of ultrasonics.

F. Fittipaldi; E. Ragozzino

1967-01-01T23:59:59.000Z

218

Effects of bulk viscosity at freezeout  

SciTech Connect (OSTI)

We investigate particle spectra and elliptic flow coefficients in relativistic heavy-ion collisions by taking into account the distortion of phase space distributions by bulk viscosity at freezeout. We first calculate the distortion of phase space distributions in a multicomponent system with Grad's 14-moment method. We find some subtle issues when macroscopic variables are matched with microscopic momentum distributions in a multicomponent system, and we develop a consistent procedure to uniquely determine the corrections to the phase space distributions. Next, we calculate particle spectra by using the Cooper-Frye formula to see the effect of the bulk viscosity. Despite the relative smallness of the bulk viscosity, we find that it is likely to have a visible effect on particle spectra and elliptic flow coefficients. This indicates the importance of taking into account bulk viscosity together with shear viscosity to constrain the transport coefficients with better accuracy from comparison with experimental data.

Monnai, Akihiko; Hirano, Tetsufumi [Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan)

2009-11-15T23:59:59.000Z

219

Using supercritical fluids to refine hydrocarbons  

DOE Patents [OSTI]

This is a method to reactively refine hydrocarbons, such as heavy oils with API gravities of less than 20.degree. and bitumen-like hydrocarbons with viscosities greater than 1000 cp at standard temperature and pressure using a selected fluid at supercritical conditions. The reaction portion of the method delivers lighter weight, more volatile hydrocarbons to an attached contacting device that operates in mixed subcritical or supercritical modes. This separates the reaction products into portions that are viable for use or sale without further conventional refining and hydro-processing techniques. This method produces valuable products with fewer processing steps, lower costs, increased worker safety due to less processing and handling, allow greater opportunity for new oil field development and subsequent positive economic impact, reduce related carbon dioxide, and wastes typical with conventional refineries.

Yarbro, Stephen Lee

2014-11-25T23:59:59.000Z

220

Effect of heat transfer on the plane-channel poiseuille flow of a thermo-viscous fluid  

Science Journals Connector (OSTI)

A steady-state plane channel flow of viscous incompressible fluid with no-slip and heat transfer boundary conditions is considered. The flow is ... induced by a fixed pressure difference and the fluid viscosity d...

S. N. Aristov; V. G. Zelenina

Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Nonlinear bulk viscosity and the stability of accelerated expansion in FRW spacetime  

E-Print Network [OSTI]

In the context of dark energy solutions, we consider a Friedmann-Robertson-Walker spacetime filled with a non-interacting mixture of dust and a viscous fluid, whose bulk viscosity is governed by the nonlinear model proposed in [15]. Through a phase space analysis of the equivalent dynamical system, existence and stability of critical solutions are established and the respective scale factors are computed. The results point towards the possibility of describing the current accelerated expansion of the Universe by means of the abovementioned nonlinear model for viscosity.

G. Acquaviva; A. Beesham

2014-05-14T23:59:59.000Z

222

VISCOSITY AND RELAXATION APPROXIMATIONS FOR HYPERBOLIC SYSTEMS OF CONSERVATION LAWS  

E-Print Network [OSTI]

VISCOSITY AND RELAXATION APPROXIMATIONS FOR HYPERBOLIC SYSTEMS deal with the approximation of conservation * *laws via viscosity or relaxation. The following topics are covered: The general structure of viscosity and relaxation approximations is discu

Tzavaras, Athanasios E.

223

VISCOSITY AND RELAXATION APPROXIMATIONS FOR HYPERBOLIC SYSTEMS OF CONSERVATION LAWS  

E-Print Network [OSTI]

VISCOSITY AND RELAXATION APPROXIMATIONS FOR HYPERBOLIC SYSTEMS OF CONSERVATION LAWS Athanasios E. Tzavaras Abstract. These lecture notes deal with the approximation of conservation laws via viscosity or relaxation. The following topics are covered: The general structure of viscosity and relaxation

Tzavaras, Athanasios E.

224

EXPERIMENTAL AND THEORETICAL DETERMINATION OF HEAVY OIL VISCOSITY UNDER RESERVOIR CONDITIONS  

SciTech Connect (OSTI)

The USA deposits of heavy oils and tar sands contain significant energy reserves. Thermal methods, particularly steam drive and steam soak, are used to recover heavy oils and bitumen. Thermal methods rely on several displacement mechanisms to recover oil, but the most important is the reduction of crude viscosity with increasing temperature. The main objective of this research is 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. First, we reviewed critically the existing literature choosing the most promising models for viscosity determination. Then, we modified an existing viscosity correlation, based on the corresponding states principle in order to fit more than two thousand commercial viscosity data. We collected data for compositional and black oil samples (absence of compositional data). The data were screened for inconsistencies resulting from experimental error. A procedure based on the monotonic increase or decrease of key variables was implemented to carry out the screening process. The modified equation was used to calculate the viscosity of several oil samples where compositional data were available. Finally, a simple procedure was proposed to calculate black oil viscosity from common experimental information such as, boiling point, API gravity and molecular weight.

Dr. Jorge Gabitto; Maria Barrufet

2003-05-01T23:59:59.000Z

225

Shear viscosity in neutron star cores  

E-Print Network [OSTI]

We calculate the shear viscosity $\\eta = \\eta_{e\\mu}+\\eta_{n}$ in a neutron star core composed of nucleons, electrons and muons ($\\eta_{e\\mu}$ being the electron-muon viscosity, mediated by collisions of electrons and muons with charged particles, and $\\eta_{n}$ the neutron viscosity, mediated by neutron-neutron and neutron-proton collisions). Deriving $\\eta_{e\\mu}$, we take into account the Landau damping in collisions of electrons and muons with charged particles via the exchange of transverse plasmons. It lowers $\\eta_{e\\mu}$ and leads to the non-standard temperature behavior $\\eta_{e\\mu}\\propto T^{-5/3}$. The viscosity $\\eta_{n}$ is calculated taking into account that in-medium effects modify nucleon effective masses in dense matter. Both viscosities, $\\eta_{e\\mu}$ and $\\eta_{n}$, can be important, and both are calculated including the effects of proton superfluidity. They are presented in the form valid for any equation of state of nucleon dense matter. We analyze the density and temperature dependence of $\\eta$ for different equations of state in neutron star cores, and compare $\\eta$ with the bulk viscosity in the core and with the shear viscosity in the crust.

P. S. Shternin; D. G. Yakovlev

2008-08-14T23:59:59.000Z

226

A new method for measuring the viscosity of nanoparticles | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

A new method for measuring the viscosity of nanoparticles A new method for measuring the viscosity of nanoparticles First direct determination of the chemical diffusivity and...

227

Design of High Viscosity Cement Gun for Vertebroplasty:.  

E-Print Network [OSTI]

??Vertebroplasty is a minimally invasive procedure for treating spine. Cement leakage is problem occurring from usage of low viscosity bone cements. High viscosity bone cements… (more)

Gupta, P.

2011-01-01T23:59:59.000Z

228

RMOTC to Test Oil Viscosity Reduction Technology  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

to Test Oil Viscosity Reduction Technology to Test Oil Viscosity Reduction Technology The Rocky Mountain Oilfield Testing Center (RMOTC) announces that the "Teapot Dome" oil field in Wyoming is hosting a series of tests funded by STWA, Inc. ("STWA") to determine the performance of its Applied Oil Technology (AOT(tm)) in reducing crude oil's viscosity to lower transportation costs for pipeline operators. The testing is managed by RMOTC, and conducted at Naval Petroleum Reserve No. 3, also known as the Teapot Dome oil field. RMOTC is providing the infrastructure and technical expertise to support companies such as STWA in their efforts to validate new technologies and bring those products and

229

Shear Viscosity from Effective Couplings of Gravitons  

E-Print Network [OSTI]

We calculate the shear viscosity of field theories with gravity duals using Kubo-formula by calculating the Green function of dual transverse gravitons and confirm that the value of the shear viscosity is fully determined by the effective coupling of transverse gravitons on the horizon. We calculate the effective coupling of transverse gravitons for Einstein and Gauss-Bonnet gravities coupled with matter fields, respectively. Then we apply the resulting formula to the case of AdS Gauss-Bonnet gravity with $F^4$ term corrections of Maxwell field and discuss the effect of $F^4$ terms on the ratio of the shear viscosity to entropy density.

Rong-Gen Cai; Zhang-Yu Nie; Ya-Wen Sun

2008-11-11T23:59:59.000Z

230

Bulk viscosity effects on elliptic flow  

E-Print Network [OSTI]

The effects of bulk viscosity on the elliptic flow $v_{2}$ are studied using realistic equation of state and realistic transport coefficients. We find that thebulk viscosity acts in a non trivial manner on $v_{2}$. At low $p_{T}$, the reduction of $v_{2}$ is even more effective compared to the case of shear viscosity, whereas at high $p_{T}$, an enhancement of $v_{2}$ compared to the ideal case is observed. We argue that this is caused by the competition of the critical behavior of the equation of state and the transport coefficients.

G. S. Denicol; T. Kodama; T. Koide; Ph. Mota

2009-07-24T23:59:59.000Z

231

Shear viscosity of $?$-stable nuclear matter  

E-Print Network [OSTI]

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

Omar Benhar; Arianna Carbone

2009-12-01T23:59:59.000Z

232

Viscosity of gaseous ethyl fluoride (HFC-161)  

Science Journals Connector (OSTI)

Abstract The paper describes an improved Maxwell type oscillating-disk viscometer. The experimental system was calibrated by argon, carbon dioxide, nitrogen, hydrogen and verified by nitrogen. The viscosities of gaseous HFC-161 were measured from 293 K to 369 K at pressures from 0.1 MPa up to the saturated vapor pressure. An empirical viscosity equation is proposed to interpolate the present experimental data as a function of density and temperature. The uncertainty of the reported viscosity was estimated to be within 1%.

Shaohua Lv; Xiaoming Zhao; Chuanqi Yao; Wei Wang; Zhikai Guo

2014-01-01T23:59:59.000Z

233

Bulk viscosity of a pion gas  

SciTech Connect (OSTI)

We compute the bulk viscosity of a gas of pions at temperatures below the QCD crossover temperature, for the physical value of m{sub {pi}}, to lowest order in chiral perturbation theory. Bulk viscosity is controlled by number-changing processes which become exponentially slow at low temperatures when the pions become exponentially dilute, leading to an exponentially large bulk viscosity {zeta}{approx}(F{sub 0}{sup 8}/m{sub {pi}}{sup 5})exp(2m{sub {pi}}/T), where F{sub 0}{approx_equal}93 MeV is the pion decay constant.

Lu Egang; Moore, Guy D. [Department of Physics, McGill University, 3600 rue University, Montreal, Quebec, H3A 2T8 (Canada)

2011-04-15T23:59:59.000Z

234

The Bulk Viscosity of a Pion Gas  

E-Print Network [OSTI]

We compute the bulk viscosity of a gas of pions at temperatures below the QCD crossover temperature, for the physical value of pion mass, to lowest order in chiral perturbation theory. Bulk viscosity is controlled by number-changing processes which become exponentially slow at low temperatures when the pions become exponentially dilute, leading to an exponentially large bulk viscosity zeta ~ (F_0^8/m_\\pi^5) exp(2m_\\pi/T), where F_0 = 93 MeV is the pion decay constant.

Egang Lu; Guy D. Moore

2011-01-31T23:59:59.000Z

235

Intrinsic viscosity of a suspension of cubes  

Science Journals Connector (OSTI)

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

Rajesh K. Mallavajula; Donald L. Koch; Lynden A. Archer

2013-11-06T23:59:59.000Z

236

Randall-Sundrum model with $?viscosity  

E-Print Network [OSTI]

We study the effect of the inclusion of bulk brane viscosity on brane world (BW) cosmology in the framework of the Eckart's theory, we focus in the Randall-Sundrum model with negative tension on the brane.

Samuel Lepe; Francisco Peña; Joel Saavedra

2008-03-04T23:59:59.000Z

237

Viscosity and jet quenching from holographic model  

E-Print Network [OSTI]

We consider the backreaction of the fundamental flavor degrees of freedom on the AdS$_5$-Schwarz background, and calculate their contributions to the shear viscosity and jet-quenching parameter of the thermal quark-gluon plasma.

Yi-hong Gao; Wei-shui Xu; Ding-fang Zeng

2007-07-05T23:59:59.000Z

238

Viscosity in the escape-rate formalism  

Science Journals Connector (OSTI)

We apply the escape-rate formalism to compute the shear viscosity in terms of the chaotic properties of the underlying microscopic dynamics. A first-passage problem is set up for the escape of the Helfand moment associated with viscosity out of an interval delimited by absorbing boundaries. At the microscopic level of description, the absorbing boundaries generate a fractal repeller. The fractal dimensions of this repeller are directly related to the shear viscosity and the Lyapunov exponent, which allows us to compute its values. We apply this method to the Bunimovich-Spohn minimal model of viscosity which is composed of two hard disks in elastic collision on a torus. These values are in excellent agreement with the values obtained by other methods such as the Green-Kubo and Einstein-Helfand formulas.

S. Viscardy and P. Gaspard

2003-10-23T23:59:59.000Z

239

Bulk Viscosity of a Pion Gas  

SciTech Connect (OSTI)

We calculate the bulk viscosity of a pion gas at low energies within the kinetic theory approach and show the importance of dealing properly with the zero modes of this transport coefficient.

Dobado, Antonio; Torres-Rincon, Juan M. [Dpto. Fisica Teorica I, Universidad Complutense de Madrid, 28040 Madrid (Spain)

2011-05-23T23:59:59.000Z

240

Viscosity at RHIC: Theory and Practice  

E-Print Network [OSTI]

Hydrodynamic behavior and the associated discussions of viscosity at RHIC has inspired a r enaissance in modeling viscous hydrodynamics. An explanation of Israel-Stewart hydrodynamics is presented here, with an emphasis on the tangible benefits compared to Navier Stokes.

Scott Pratt

2008-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Viscosity of Liquids and Colloidal Solutions  

Science Journals Connector (OSTI)

... conference it was decided to hold a further conference, in the following year, on "Viscosity of Liquids and Colloidal Solutions". This took place just before the German invasion and ...

G. W. SCOTT BLAIR

1945-08-04T23:59:59.000Z

242

Energy-saving technologies in viscose manufacture  

Science Journals Connector (OSTI)

-- Results of the realization of energy-economical technologies in the processes of continuous deaeration and two-stage vacuum crystallization of sodium sulfate from technological solutions in viscose manufact...

V. D. Chernov; I. Z. Éifer; N. S. Markov; A. A. Yakobuk; Yu. N. Fikhman

243

Measurement of DWPF glass viscosity - Final Report  

SciTech Connect (OSTI)

This report details the results of a scoping study funded by the Defense Waste Processing Facility (DWPF) for the measurement of melt viscosities for simulated glasses representative of Macrobatch 2 (Tank 42/51 feed).

Harbour, J.R.

2000-02-17T23:59:59.000Z

244

Shear viscosity and shear thinning in two-dimensional Yukawa liquids  

E-Print Network [OSTI]

A two-dimensional Yukawa liquid is studied using two different nonequilibrium molecular dynamics simulation methods. Shear viscosity values in the limit of small shear rates are reported for a wide range of Coulomb coupling parameter and screening length. At high shear rates it is demonstrated that this liquid exhibits shear thinning, i.e., the viscosity $\\eta$ diminishes with increasing shear rate. It is expected that two-dimensional dusty plasmas will exhibit this effect.

Z. Donkó; J. Goree; P. Hartmann; K. Kutasi

2006-03-24T23:59:59.000Z

245

Shear viscosity of degenerate electron matter  

E-Print Network [OSTI]

We calculate the partial electron shear viscosity $\\eta_{ee}$ limited by electron-electron collisions in a strongly degenerate electron gas taking into account the Landau damping of transverse plasmons. The Landau damping strongly suppresses $\\eta_{ee}$ in the domain of ultrarelativistic degenerate electrons and modifies its %asymptotic temperature behavior. The efficiency of the electron shear viscosity in the cores of white dwarfs and envelopes of neutron stars is analyzed.

P. S. Shternin

2008-03-27T23:59:59.000Z

246

Tsunamis, Viscosity and the HBT Puzzle  

E-Print Network [OSTI]

The equation of state and bulk and shear viscosities are shown to be able to affect the transverse dynamics of a central heavy ion collision. The net entropy, along with the femtoscopic radii are shown to be affected at the 10-20% level by both shear and bulk viscosity. The degree to which these effects help build a tsunami-like pulse is also discussed.

Scott Pratt

2007-10-30T23:59:59.000Z

247

Viscosity of network liquids within Doremus approach  

Science Journals Connector (OSTI)

Defect-mediated diffusion and viscous flow of network forming liquids have been investigated. An analytical formula of viscosity has been derived with two-exponential forms demonstrating high activation energy at low temperatures and low activation energy at high temperatures with Arrhenius-type behavior for both high and low temperature limits. Calculated data for the viscosity of silica glass are in excellent agreement with the experimental data.

Michael I. Ojovan; William E. Lee

2004-01-01T23:59:59.000Z

248

Viscosity Dependence of the Folding Rates of Proteins  

Science Journals Connector (OSTI)

The viscosity (?) dependence of the folding rates for four sequences (the native state of three sequences is a ? sheet, while the fourth forms an ? helix) is calculated for off-lattice models of proteins. Assuming that the dynamics is given by the Langevin equation, we show that the folding rates increase linearly at low viscosities ?, decrease as 1/? at large ?, and have a maximum at intermediate values. The Kramers' theory of barrier crossing provides a quantitative fit of the numerical results. By mapping the simulation results to real proteins we estimate that for optimized sequences the time scale for forming a four turn ?-helix topology is about 500 ns, whereas for ? sheet it is about 10 ?s.

D. K. Klimov and D. Thirumalai

1997-07-14T23:59:59.000Z

249

The dependence of suspension viscosity on particle size, shear rate, and solvent viscosity.  

E-Print Network [OSTI]

??The relative viscosity of a mono-disperse suspension of glass particles can vary drastically depending on a number of factors, including but not limited to the… (more)

Pavlik, Marc

2011-01-01T23:59:59.000Z

250

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

SciTech Connect (OSTI)

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

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

2009-01-01T23:59:59.000Z

251

Prediction of refrigerant-lubricant viscosity using the general PC-SAFT friction theory  

Science Journals Connector (OSTI)

Abstract In this work, a friction theory (f-theory) viscosity model founded on the perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state (EoS) was used to calculate the viscosity of refrigerant-oil mixtures. The model, which links viscosity to the repulsive and attractive pressure terms of the PC-SAFT EoS, can provide satisfactory viscosity predictions of mixtures of carbon dioxide (R-744) and two synthetic lubricants, namely, a polyolester (POE) ISO VG 68 and an alkylbenzene (AB) ISO VG 32, as well as mixtures of isobutane (R-600a) and two other synthetic lubricants, a POE ISO VG 7 and an AB ISO VG 5. The root-mean square (RMS) deviations related to the viscosity prediction were 0.69% (R-600a/POE ISO 7), 0.99% (R-600a/AB ISO VG 5), 3.16% (R-744/POE ISO VG 68) and 3.18% (R-744/AB ISO VG 32).

Moisés A. Marcelino Neto; Jader R. Barbosa Jr.

2014-01-01T23:59:59.000Z

252

Entropy viscosity Jean-Luc Guermond, B. Popov  

E-Print Network [OSTI]

Entropy viscosity Jean-Luc Guermond, B. Popov Department of Mathematics Texas A&M University-Luc Guermond, B. Popov Residual/Entropy viscosity #12;Acknowledgments Collaborator: Richard Pasquetti, Univ/Entropy viscosity #12;Outline 1 TRANSPORT EQUATION Jean-Luc Guermond, B. Popov Residual/Entropy viscosity #12

Guermond, Jean-Luc

253

VISCOSITY SOLUTIONS TO DEGENERATE COMPLEX MONGE-AMP`ERE EQUATIONS  

E-Print Network [OSTI]

VISCOSITY SOLUTIONS TO DEGENERATE COMPLEX MONGE-AMP`ERE EQUATIONS PHILIPPE EYSSIDIEUX, VINCENT an alternative approach based on the concept of viscosity solutions and compare systematically viscosity concepts PDE approach to second-order degenerate elliptic equations is the method of viscosity solutions

Boyer, Edmond

254

Geothermal fracture stimulation technology. Volume III. Geothermal fracture fluids  

SciTech Connect (OSTI)

A detailed study of all available and experimental frac fluid systems is presented. They have been examined and tested for physical properties that are important in the stimulation of hot water geothermal wells. These fluids consist of water-based systems containing high molecular weight polymers in the uncrosslinked and crosslinked state. The results of fluid testing for many systems are summarized specifically at geothermal conditions or until breakdown occurs. Some of the standard tests are ambient viscosity, static aging, high temperature viscosity, fluid-loss testing, and falling ball viscosity at elevated temperatures and pressures. Results of these tests show that unalterable breakdown of the polymer solutions begins above 300/sup 0/F. This continues at higher temperatures with time even if stabilizers or other high temperature additives are included.

Not Available

1981-01-01T23:59:59.000Z

255

Effective surface dilatational viscosity of highly concentrated particle-laden interfaces  

E-Print Network [OSTI]

The effective surface dilatational viscosity is calculated of a flat interface separating two immiscible fluids laden with half-immersed monodisperse rigid spherical non-Brownian particles in the limit of high particle concentration. The derivation is based upon the facts that (i) highly-concentrated particle arrays in a plane form hexagonal structure, and (ii) the dominant contribution to the viscous dissipation rate arises in the thin gaps between neighboring particles.

Lishchuk, S V

2014-01-01T23:59:59.000Z

256

Experimental Investigation of the Effective Foam Viscosity in Unsaturated Porous Media  

SciTech Connect (OSTI)

Foam has the potential to effectively carry and distribute either aqueous or gaseous amendments to the deep vadose zone for contaminant remediation. However, the transport of foam in porous media is complicated because flow characteristics such as the effective viscosity are affected not only by foam properties but also by the sediment properties and flow conditions. We determined the average effective foam viscosity via a series of laboratory experiments and found that the effective foam viscosity increased with the liquid fraction in foam, the injection rate, and sediment permeability. These impacts are quantified with an empirical expression, which is further demonstrated with data from literature. The results show that the liquid fraction in foam and sediment permeability are two primary factors affecting effective foam viscosity. These results suggest that, when foam is used in deep vadose zone remediation, foam flow will not suffer from gravitational drainage and can distribute amendments uniformly in heterogeneous sediments.

Zhang, Z. F.; Zhong, Lirong; White, Mark D.; Szecsody, James E.

2012-11-01T23:59:59.000Z

257

Thermal Diffusivity and Viscosity of Suspensions of Disc Shaped Nanoparticles  

E-Print Network [OSTI]

In this work we conduct a transient heat conduction experiment with an aqueous suspension of nanoparticle disks of Laponite JS, a sol forming grade, using laser light interferometry. The image sequence in time is used to measure thermal diffusivity and thermal conductivity of the suspension. Imaging of the temperature distribution is facilitated by the dependence of refractive index of the suspension on temperature itself. We observe that with the addition of 4 volume % of nano-disks in water, thermal conductivity of the suspension increases by around 30%. A theoretical model for thermal conductivity of the suspension of anisotropic particles by Fricke as well as by Hamilton and Crosser explains the trend of data well. In turn, it estimates thermal conductivity of the Laponite nanoparticle itself, which is otherwise difficult to measure in a direct manner. We also measure viscosity of the nanoparticle suspension using a concentric cylinder rheometer. Measurements are seen to follow quite well, the theoretical relation for viscosity of suspensions of oblate particles that includes up to two particle interaction. This result rules out the presence of clusters of particles in the suspension. The effective viscosity and thermal diffusivity data show that the shape of the particle has a role in determining enhancement of thermophysical properties of the suspension.

Susheel S. Bhandari; K. Muralidhar; Yogesh M Joshi

2014-03-05T23:59:59.000Z

258

Randall-Sundrum Model in the Presence of a Brane Bulk Viscosity  

E-Print Network [OSTI]

The presence of a bulk viscosity for the cosmic fluid on a single Randall-Sundrum brane is considered. The spatial curvature is assumed to be zero. The five-dimensional Friedmann equation is derived, together with the energy conservation equation for the viscous fluid. These governing equations are solved for some special cases: (i) in the low-energy limit when the matter energy density is small compared with brane tension; (ii) for a matter-dominated universe, and (iii) for a radiation-dominated universe. Rough numerical estimates, for the extreme case when the universe is at its Planck time, indicate that the viscous effect can be significant.

Brevik, I

2004-01-01T23:59:59.000Z

259

Entropy viscosity method applied to Euler equations  

SciTech Connect (OSTI)

The entropy viscosity method [4] has been successfully applied to hyperbolic systems of equations such as Burgers equation and Euler equations. The method consists in adding dissipative terms to the governing equations, where a viscosity coefficient modulates the amount of dissipation. The entropy viscosity method has been applied to the 1-D Euler equations with variable area using a continuous finite element discretization in the MOOSE framework and our results show that it has the ability to efficiently smooth out oscillations and accurately resolve shocks. Two equations of state are considered: Ideal Gas and Stiffened Gas Equations Of State. Results are provided for a second-order time implicit schemes (BDF2). Some typical Riemann problems are run with the entropy viscosity method to demonstrate some of its features. Then, a 1-D convergent-divergent nozzle is considered with open boundary conditions. The correct steady-state is reached for the liquid and gas phases with a time implicit scheme. The entropy viscosity method correctly behaves in every problem run. For each test problem, results are shown for both equations of state considered here. (authors)

Delchini, M. O.; Ragusa, J. C. [Nuclear Engineering Department, Texas A and M University, 3133 TAMU, College Station, TX 77843-3133 (United States); Berry, R. A. [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3840 (United States)

2013-07-01T23:59:59.000Z

260

Analysis of drilling fluid rheology and tool joint effect to reduce errors in hydraulics calculations  

E-Print Network [OSTI]

325 Temperature ?F Plastic Viscosity, cp 2000 psi 4000 psi 6000 psi 8000 psi 10000 psi Fig. 3.4?Effect of pressure and temperature on plastic viscosity (from Bogot? Technical Center... 0 200 400 600 800 1000 1200 g (sec-1) tttt,(lbf/100 ft 2 ) Fig. 4.1?Newtonian fluid rheogram. 26 To estimate viscosity in field units (cp) we have to convert by the following equation: m =47880m/100...

Viloria Ochoa, Marilyn

2006-10-30T23:59:59.000Z

Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Shear Viscosity of a Hot Pion Gas  

E-Print Network [OSTI]

The shear viscosity of an interacting pion gas is studied using the Kubo formalism as a microscopic description of thermal systems close to global equilibrium. We implement the skeleton expansion in order to approximate the retarded correlator of the viscous part of the energy-momentum tensor. After exploring this in $g\\phi^4$ theory we show how the skeleton expansion can be consistently applied to pions in chiral perturbation theory. The shear viscosity $\\eta$ is determined by the spectral width, or equivalently, the mean free path of pions in the heat bath. We derive a new analytical result for the mean free path which is well-conditioned for numerical evaluation and discuss the temperature and pion-mass dependence of the mean free path and the shear viscosity. The ratio $\\eta/s$ of the interacting pion gas exceeds the lower bound $1/4\\pi$ from AdS/CFT correspondence.

Robert Lang; Norbert Kaiser; Wolfram Weise

2012-09-04T23:59:59.000Z

262

Models of magnetic-field evolution and effective viscosity in weakly collisional extragalactic plasmas  

E-Print Network [OSTI]

In weakly collisional extragalactic plasmas such as the intracluster medium, viscous stress and the rate of change of the magnetic-field strength are proportional to the local pressure anisotropy, so subject to constraints imposed by the pressure-anisotropy-driven mirror and firehose instabilities and controlled by the local instantaneous plasma beta. The dynamics of such plasmas is dramatically different from a conventional MHD fluid. The plasma is expected to stay locally in a marginal state with respect to the instabilities, but how it does this is an open question. Two models of magnetic-field evolution are investigated. In the first, marginality is achieved via suppression of the rate of change of the field. In the second, the instabilities give rise to anomalous collisionality, reducing pressure anisotropy to marginal - at the same time decreasing viscosity and so increasing the turbulent rate of strain. Implications of these models are studied in a simplified 0D setting. In the first model, the field grows explosively but on a time scale that scales with initial beta, while in the second, dynamical field strength can be reached in one large-scale turbulence turn-over time regardless of the initial seed. Both models produce very intermittent fields. Both also suffer from strong constraints on their applicability: for typical cluster-core conditions, scale separation between the fluid motions and the microscale fluctuations breaks down at beta~10^5-10^4. At larger beta (weaker fields), a fully collisionless plasma dynamo theory is needed in order to justify the growth of the field from a tiny primordial seed. However, the models discussed here are appropriate for studying the structure of the currently observed field as well as large-scale dynamics and thermodynamics of the magnetized ICM or similarly dilute astrophysical plasmas.

Federico Mogavero; Alexander A. Schekochihin

2014-03-04T23:59:59.000Z

263

Shear Viscosity of a Unitary Fermi Gas  

E-Print Network [OSTI]

We present the first ab initio determination of the shear viscosity eta of the Unitary Fermi Gas, based on finite temperature quantum Monte Carlo calculations and the Kubo linear-response formalism. We determine the temperature dependence of the shear viscosity to entropy density ratio eta/s. The minimum of eta/s appears to be located above the critical temperature for the superfluid-to-normal phase transition with the most probable value being eta/s approx 0.2 hbar/kB, which almost saturates the Kovtun-Son-Starinets universal value hbar/(4 pi kB).

Gabriel Wlaz?owski; Piotr Magierski; Joaquín E. Drut

2012-04-01T23:59:59.000Z

264

Viscosity of Two-Dimensional Suspensions  

Science Journals Connector (OSTI)

Over a range of conditions, lipid and surfactant monolayers exhibit coexistence of discrete solid domains in a continuous liquid. The surface shear viscosity, ?s, of such monolayers collapses onto a single curve: ?s/?so=[1-(A/Ac)]-1, in which ?so is the viscosity of the liquid phase, A is the area fraction of the solid phase measured by fluorescence microscopy, and Ac is a critical solid phase fraction. This scaling relationship is directly analogous to that of three-dimensional dispersion of spheres in a solvent with long-range repulsive interactions, with area fraction replacing volume fraction.

Junqi Ding; Heidi E. Warriner; Joseph A. Zasadzinski

2002-04-08T23:59:59.000Z

265

Shear Viscosity in a Gluon Gas  

Science Journals Connector (OSTI)

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

Zhe Xu and Carsten Greiner

2008-04-29T23:59:59.000Z

266

Viscosity of a nanoconfined liquid during compression  

Science Journals Connector (OSTI)

The viscous behavior of liquids under nanoconfinement is not well understood. Using a small-amplitude atomic force microscope we found bulk-like viscosity in a nanoconfined weakly interacting liquid. A further decrease in viscosity was observed at confinement sizes of a just few molecular layers. Overlaid over the continuum viscous behavior we measured non-continuum stiffness and damping oscillations. The average stiffness of the confined liquid was found to scale linearly with the size of the confining tip while the damping scales with the radius of curvature of the tip end.

Edward L. Kramkowski; Peter J. Ochs; David M. Wilson

2014-01-01T23:59:59.000Z

267

Viscosity model for polydisperse polymer melts  

Science Journals Connector (OSTI)

A simple superposition model was used to define the relationship between molecular weight distribution and shear viscosity for linear polymeric systems. Gel permeation chromatography data for molecular weight distributions were fitted using statistical distribution functions. A simple superposition model was then employed to calculate the shear viscosity for the systems investigated. The effect of polydispersity on the shape of the flow curves was calculated. The simplicity of the model makes feasible its use in numerical simulations of complex geometries as encountered in polymer processing equipment. The present study also sheds some light on the relationship between entanglement and disentanglement phenomena in polymeric systems.

D. Nichetti; I. Manas-Zloczower

1998-01-01T23:59:59.000Z

268

Monte Carlo uncertainty estimation for an oscillating-vessel viscosity measurement  

SciTech Connect (OSTI)

This paper discusses the initial design and evaluation of a high temperature viscosity measurement system with the focus on the uncertainty assessment. Numerical simulation of the viscometer is used to estimate viscosity uncertainties through the Monte Carlo method. The simulation computes the system response for a particular set of inputs (viscosity, moment of inertia, spring constant and hysteretic damping), and the viscosity is calculated using two methods: the Roscoe approximate solution and a numerical-fit method. For numerical fitting, a residual function of the logarithmic decay of oscillation amplitude and oscillation period is developed to replace the residual function of angular oscillation, which is mathematically stiff. The results of this study indicate that the method using computational solution of the equations and fitting for the parameters should be used, since it almost always out-performs the Roscoe approximation in uncertainty. The hysteretic damping and spring stiffness uncertainties translate into viscosity uncertainties almost directly, whereas the moment of inertial and vessel-height uncertainties are magnified approximately two-fold. As the hysteretic damping increases, so does the magnification of its uncertainty, therefore it should be minimized in the system design. The result of this study provides a general guide for the design and application of all oscillation-vessel viscosity measurement systems.

K. Horne; H. Ban; R. Fielding; R. Kennedy

2012-08-01T23:59:59.000Z

269

Under consideration for publication in J. Fluid Mech. 1 Splashing from drop impact into a deep  

E-Print Network [OSTI]

surrounding gases. We find that the splashing threshold depends on the gas's dynamic viscosity, but not its, and disintegrates into a spray of secondary droplets. Nonetheless, many basic details of this process remain obscure. Fezzaa and R. D. Deegan Fluid Viscosity Density Surface tension Drop Diameter (cp) (g/cm3 ) (dyne/cm) (cm

Deegan, Robert

270

Leakage estimation of incompressible fluids in stepped labyrinth seals  

E-Print Network [OSTI]

factor g = acceleration due to gravity h = height of tooth m = pitch of tooth m = mass flowrate n = number of throttles r = tooth to step distance s = width of tooth t = step height in stepped labyrinth seals u = fluid velocity spec'fic volume... D = seal diameter H OC = tooth height to clearance ratio pressure Re = Reynolds number WTOP tooth width to pitch ratio flow coefficient car v-over coefficient absolute viscosity kinematic viscosity xv1 aensity subscripts: o = inlet value...

Chi, Daesung

2012-06-07T23:59:59.000Z

271

A Smoothed Particle Hydrodynamics-Based Fluid Model With a Spatially...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

A Smoothed Particle Hydrodynamics-Based Fluid Model With a Spatially Dependent Viscosity Authors: Martys, N.S., George, W.L., Chun, B., Lootens, D. A smoothed particle...

272

Identification of an average temperature and a dynamical pressure in a multitemperature mixture of fluids  

E-Print Network [OSTI]

Identification of an average temperature and a dynamical pressure in a multitemperature mixture pressure even if the fluids have a zero bulk viscosity. The nonequilib- rium dynamical pressure can

Boyer, Edmond

273

Viscosity to entropy ratio at extremality  

E-Print Network [OSTI]

Assuming gauge theory realization at the boundary, we show that the viscosity to entropy ratio is 1/(4 pi) where the bulk is represented by a large class of extremal black holes in anti-de Sitter space. In particular, this class includes multiple R-charged black holes in various dimensions.

Sayan K. Chakrabarti; Sachin Jain; Sudipta Mukherji

2009-10-27T23:59:59.000Z

274

Electron perpendicular viscosity in Braginskii's equations  

SciTech Connect (OSTI)

The viscosity coefficient of the electron perpendicular stress tensor in Braginskii's theory is corrected by the addition of a term of the same order of magnitude, through the inclusion of a term beyond pitch angle scattering in the mass-ratio expansion of the electron-ion collision operator.

Wong, S. K.; Chan, V. S. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)] [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)

2013-07-15T23:59:59.000Z

275

Hydrodynamic Modeling and the QGP Shear Viscosity  

E-Print Network [OSTI]

In this article, we will briefly review the recent progress on hydrodynamic modeling and the extraction of the quark-gluon plasma (QGP) specific shear viscosity with an emphasis on results obtained from the hybrid model VISHNU that couples viscous hydrodynamics for the macroscopic expansion of the QGP to the hadron cascade model for the microscopic evolution of the late hadronic stage.

Huichao Song

2012-07-10T23:59:59.000Z

276

From Stopping to Viscosity in Nuclear Reactions  

SciTech Connect (OSTI)

Data on stopping in intermediate-energy central heavy-ion collisions are analyzed following transport theory based on the Boltzmann equation. In consequence, values of nuclear shear viscosity are inferred. The inferred values are significantly larger than obtained for free nucleon dispersion relations and free nucleon-nucleon cross sections.

Danielewicz, Pawel; Barker, Brent; Shi Lijun [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy Michigan State University, East Lansing, Michigan 48824 (United States)

2009-05-07T23:59:59.000Z

277

From Stopping to Viscosity in Nuclear Reactions  

E-Print Network [OSTI]

Data on stopping in intermediate-energy central heavy-ion collisions are analyzed following transport theory based on the Boltzmann equation. In consequence, values of nuclear shear viscosity are inferred. The inferred values are significantly larger than obtained for free nucleon dispersion relations and free nucleon-nucleon cross sections.

Danielewicz, P; Shi, L

2009-01-01T23:59:59.000Z

278

From Stopping to Viscosity in Nuclear Reactions  

E-Print Network [OSTI]

Data on stopping in intermediate-energy central heavy-ion collisions are analyzed following transport theory based on the Boltzmann equation. In consequence, values of nuclear shear viscosity are inferred. The inferred values are significantly larger than obtained for free nucleon dispersion relations and free nucleon-nucleon cross sections.

P. Danielewicz; B. Barker; L. Shi

2009-03-14T23:59:59.000Z

279

Shear Viscosity from the Effective Coupling of Gravitons  

E-Print Network [OSTI]

We review the progress in the holographic calculation of shear viscosity for strongly coupled field theories. We focus on the calculation of shear viscosity from the effective coupling of transverse gravitons and present some explicit examples.

Rong-Gen Cai; Zhang-Yu Nie; Ya-Wen Sun

2010-06-03T23:59:59.000Z

280

Shear viscosity of CFT plasma at finite coupling  

E-Print Network [OSTI]

We present evidence for the universality of the shear viscosity of conformal gauge theory plasmas beyond infinite coupling. We comment of subtleties of computing the shear viscosity in effective models of gauge/gravity correspondence rather than in string theory.

Alex Buchel

2008-04-19T23:59:59.000Z

Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Relation between viscosity and stability for heavy oil emulsions  

E-Print Network [OSTI]

The relation between viscosity and stability has been hics. found by investigating the effect of surfactant concentration on emulsion stability. Based on the Bingham plastic model for viscosity as a function of shear rate, two parameters were found...

Ye, Sherry Qianwen

2012-06-07T23:59:59.000Z

282

Bulk viscosity and r-modes of neutron stars  

E-Print Network [OSTI]

The bulk viscosity due to the non-leptonic process involving hyperons in $K^-$ condensed matter is discussed here. We find that the bulk viscosity is modified in a superconducting phase. Further, we demonstrate how the exotic bulk viscosity coefficient influences $r$-modes of neutron stars which might be sources of detectable gravitational waves.

Debarati Chatterjee; Debades Bandyopadhyay

2008-08-08T23:59:59.000Z

283

VISCOSITY SOLUTIONS OF HAMILTON-JACOBI EQUATIONS, AND ASYMPTOTICS FOR  

E-Print Network [OSTI]

VISCOSITY SOLUTIONS OF HAMILTON-JACOBI EQUATIONS, AND ASYMPTOTICS FOR HAMILTONIAN SYSTEMS DIOGO. In this paper we apply the theory of viscosity solu- tions of Hamilton-Jacobi equations to understand) with cer- tain minimizing properties) and viscosity solutions of Hamilton-Jacobi equations (2) H(P + Dxu, x

284

VISCOSITY SOLUTIONS OF FULLY NONLINEAR ELLIPTIC PATH DEPENDENT PDES  

E-Print Network [OSTI]

VISCOSITY SOLUTIONS OF FULLY NONLINEAR ELLIPTIC PATH DEPENDENT PDES ZHENJIE REN Abstract, inspired by [3], we define the viscosity solution, by using the nonlinear expectation. The paper contains , that for any bounded viscosity subsolution u1 and Key words and phrases. Path dependent PDEs, Dirichlet problem

Paris-Sud XI, Université de

285

Viscosity Control of the Composition of Ocean Floor Volcanics  

Science Journals Connector (OSTI)

4 February 1971 research-article Viscosity Control of the Composition of Ocean Floor...environment. Instead it is postulated that the viscosity exercises a control by limiting the range...magmas (to those with a sufficiently low viscosity) which is capable of penetrating the...

1971-01-01T23:59:59.000Z

286

Viscosity of magmatic liquids: A model Daniele Giordano a,  

E-Print Network [OSTI]

Viscosity of magmatic liquids: A model Daniele Giordano a, , James K. Russell b , Donald B: C.P. Jaupart Keywords: viscosity model silicate-melts volatile-bearing-melts glass transition fragility The viscosity of silicate melts controls magma transport dynamics, eruption style and rates

Russell, Kelly

287

Viscosity and Relaxation Approximation for Hyperbolic Systems of Conservation Laws  

E-Print Network [OSTI]

Viscosity and Relaxation Approximation for Hyperbolic Systems of Conservation Laws Athanasios E with the approximation of conservation laws via viscosity or relaxation. The following topics are covered: The general structure of viscosity and relaxation approximations is discussed, as suggested by the second law

Tzavaras, Athanasios E.

288

Bulk viscosity of gauge theory plasma at strong coupling  

E-Print Network [OSTI]

We propose a lower bound on bulk viscosity of strongly coupled gauge theory plasmas. Using explicit example of the N=2^* gauge theory plasma we show that the bulk viscosity remains finite at a critical point with a divergent specific heat. We present an estimate for the bulk viscosity of QGP plasma at RHIC.

Alex Buchel

2007-08-27T23:59:59.000Z

289

Viscosity, hard sphere diameter and interionic potential for liquid lead  

E-Print Network [OSTI]

L-347 Viscosity, hard sphere diameter and interionic potential for liquid lead G. Chaussemy The Macedo-Litovitz equation for a hard sphere liquid provides a satisfactory model for the viscosity of lead and molecular dynamics. The activation energy for viscosity (0.07 eV) is similar to the height of the interionic

Boyer, Edmond

290

VISCOSITY SOLUTIONS OF HAMILTONJACOBI EQUATIONS WITH DISCONTINUOUS COEFFICIENTS  

E-Print Network [OSTI]

VISCOSITY SOLUTIONS OF HAMILTON­JACOBI EQUATIONS WITH DISCONTINUOUS COEFFICIENTS GIUSEPPE MARIA of viscosity solution to the Cauchy problem, and that the front tracking algorithm yields an L contractive semigroup. We define a viscosity solution by treating the discontinuities in the coefficients analogously

291

Viscosity dependence of geminate recombination efficiency after bimolecular charge separation  

E-Print Network [OSTI]

Viscosity dependence of geminate recombination efficiency after bimolecular charge separation A. A viscosity dependence. As a result the latter becomes nonmonotonous, provided the kinetic controlled ionization gives way to a diffusional one, creating the more remote ions the higher the solvent viscosity

Burshtein, Anatoly

292

VISCOSITY OF CONCENTRATED SUSPENSIONS: INFLUENCE OF CLUSTER FORMATION  

E-Print Network [OSTI]

1 VISCOSITY OF CONCENTRATED SUSPENSIONS: INFLUENCE OF CLUSTER FORMATION V.Starov1 , V.Zhdanov1 , M and these forces determine both structure and size of clusters. We assume that viscosity of concentrated suspension of viscosity on a concentration of dispersed particles taking into account cluster formation, is deduced. Under

Boyer, Edmond

293

Miscibility, solubility, viscosity, and density measurements for R-236fa with potential lubricants. Final report  

SciTech Connect (OSTI)

The report gives results of miscibility, solubility, viscosity, and density measurements for refrigerant R-236fa and two potential lubricants. (The data are needed to determine the suitability of refrigerant/lubricant combinations for use in refrigeration systems.) The tested oils were pentaerythritol ester mixed-acid (ISO68), hereafter SW-68 manufactured by Castrol, and polyol ester mixed-acid (ISO46), hereafter Arctic-46 manufactured by Mobil. Miscibility was measured in a series of miniature test cells submerged in a constant temperature bath, precisely controlled over a temperature range of -50 to 90 C. Solubility, viscosity, and density data were also obtained for R-236fa mixed with the two oils for a refrigerant concentration of 0 to 40 wt % refrigerant over a temperature range of 30 to 100 C. This research shows that: (1) solubility, viscosity, and density are functions of temperature and concentration, (2) solubility increases with increasing temperature and refrigerant concentration (i.e., mass fraction of refrigerant). (3) viscosity decreases with increasing temperature and refrigerant concentration, and (4) density decreases with increasing temperature but increases with increasing refrigerant concentration. R-114 and naphthenic mineral oil were also tested.

Kang, H.M.; Pate, M.B.

1999-02-01T23:59:59.000Z

294

Fluid Volumes: The Program “FLUIDS  

Science Journals Connector (OSTI)

This chapter describes the program FLUIDS. The mathematical model underlying this program contains over 200 variables and describes control mechanisms of body fluid volumes and electrolytes as well as respirat...

Fredericus B. M. Min

1993-01-01T23:59:59.000Z

295

Pumping viscoelastic two-fluid media  

E-Print Network [OSTI]

Using a two-fluid model for viscoelastic polymer solutions, we study analytically fluid transport driven by a transverse, small amplitude traveling wave propagation. The pumping flow far from the waving boundary is shown to be strongly wave number and viscosity dependent, in contrast to a viscous Newtonian fluid. We find the two qualitatively different regimes: In one regime relevant to small wave numbers, the fluidic transport is almost the same as the Newtonian case, and uniform viscoelastic constitutive equations provide a good approximation. In the other regime, the pumping is substantially decreased because of the gel-like character. The boundary separating these two regimes is clarified. Our results suggest possible needs of two-fluid descriptions for the transport and locomotion in biological fluids with cilia and flagella.

Hirofumi Wada

2010-04-08T23:59:59.000Z

296

Viscosity and Light Scattering in Critical Mixtures  

Science Journals Connector (OSTI)

Simultaneous measurements of both viscosity and light scattering are performed on two critical mixtures. The first one is a triethylamine-water solution, which exhibits a lower consolute point, the second one a methanol-ciclohexane mixture with an upper consolute point. It is found that the singular behavior of viscosity cannot be fitted by a simple power law, nor by a logarithmic one, in the entire range of temperature. The asymptotic behavior, however, tends to become logarithmic as the critical temperature is approached. The simultaneous observation of scattered light allows one to exclude the intervention of spurious processes, like a breaking of correlations because of impurities. In addition, it is shown that the correlation length seems to depend mainly on the reduced temperature, irrespective of the system under examination.

S. Ballaro'; G. Maisano; P. Migliardo; F. Wanderlingh

1972-10-01T23:59:59.000Z

297

Viscosity of a mixture of soft spheres  

Science Journals Connector (OSTI)

The viscosity of a 50% mixture of soft spheres (i.e., particles which interact according to the force law ?=dr12) has been simulated by applying nonequilibrium molecular dynamics to a system of 108 particles. Results for several size (actually d) and mass differences are given and compared with the predictions of a conformal-solution Van der Waals 1 theory. To construct this theory, it was necessary to derive a mixing rule for the mass. Overall, agreement between theory and simulation is satisfactory to size differences of about 14% and to mass differences of about 5%. It is pointed out that nonequilibrium molecular dynamics is a powerful technique and appears well suited to this particular application: The simulated viscosity of the mixture can be obtained to within about 5% accuracy for the 108-particle system by applying a shear to the system and following its behavior for about 7000 time steps.

Denis J. Evans and H. J. M. Hanley

1979-10-01T23:59:59.000Z

298

Viscosity, Black Holes, and Quantum Field Theory  

E-Print Network [OSTI]

We review recent progress in applying the AdS/CFT correspondence to finite-temperature field theory. In particular, we show how the hydrodynamic behavior of field theory is reflected in the low-momentum limit of correlation functions computed through a real-time AdS/CFT prescription, which we formulate. We also show how the hydrodynamic modes in field theory correspond to the low-lying quasinormal modes of the AdS black p-brane metric. We provide a proof of the universality of the viscosity/entropy ratio within a class of theories with gravity duals and formulate a viscosity bound conjecture. Possible implications for real systems are mentioned.

D. T. Son; A. O. Starinets

2007-04-02T23:59:59.000Z

299

Nonlinear Simulations of Peeling-Ballooning Modes with Anomalous Electron Viscosity and their Role in Edge Localized Mode Crashes  

SciTech Connect (OSTI)

A minimum set of equations based on the peeling-ballooning (P-B) model with nonideal physics effects (diamagnetic drift, ExB drift, resistivity, and anomalous electron viscosity) is found to simulate pedestal collapse when using the new BOUT++ simulation code, developed in part from the original fluid edge code BOUT. Nonlinear simulations of P-B modes demonstrate that the P-B modes trigger magnetic reconnection, which leads to the pedestal collapse. With the addition of a model of the anomalous electron viscosity under the assumption that the electron viscosity is comparable to the anomalous electron thermal diffusivity, it is found from simulations using a realistic high-Lundquist number that the pedestal collapse is limited to the edge region and the edge localized mode (ELM) size is about 5%-10% of the pedestal stored energy. This is consistent with many observations of large ELMs.

Xu, X. Q.; Umansky, M. V. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Dudson, B.; Wilson, H. [University of York, Heslington, York YO10 5DD (United Kingdom); Snyder, P. B. [General Atomics, San Diego, California 92186 (United States)

2010-10-22T23:59:59.000Z

300

Shear viscosity of a nonperturbative gluon plasma  

E-Print Network [OSTI]

Shear viscosity is evaluated within a model of the gluon plasma, which is based entirely on the stochastic nonperturbative fields. We consider two types of excitations of such fields, which are characterized by the thermal correlation lengths ~ 1/(g^2 T) and ~ 1/(g^4 T), where "g" is the finite-temperature Yang-Mills coupling. Excitations of the first type correspond to the genuine nonperturbative stochastic Yang-Mills fields, while excitations of the second type mimic the known result for the shear viscosity of the perturbative Yang-Mills plasma. We show that the excitations of the first type produce only an O(g^{10})-correction to this result. Furthermore, a possible interference between excitations of these two types yields a somewhat larger, O(g^7), correction to the leading perturbative Yang-Mills result. Our analysis is based on the Fourier transformed Euclidean Kubo formula, which represents an integral equation for the shear spectral density. This equation is solved by seeking the spectral density in the form of the Lorentzian Ans\\"atze, whose widths are defined by the two thermal correlation lengths and by their mean value, which corresponds to the said interference between the two types of excitations. Thus, within one and the same formalism, we reproduce the known result for the shear viscosity of the perturbative Yang-Mills plasma, and account for possible nonperturbative corrections to it.

Dmitri Antonov

2012-02-10T23:59:59.000Z

Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Viscosity of a Suspension with Internal Rotation  

Science Journals Connector (OSTI)

When an insulating particle immersed into a low conducting liquid is submitted to a sufficiently high DC field E it can rotate spontaneously around itself along any axis perpendicular to the electric field. This symmetry break is known as Quincke rotation and could have important consequences on the rheology of such a suspension of particles (insulating particles dispersed in a slightly conducting liquid). Indeed if the suspension is subject to a shear rate and a DC electric field is applied in the velocity gradient direction the spin rate of the particles is greater than in the absence of an E field so that the macroscopic spin rate of the particles drives the suspending liquid and thus leads to a decrease of the apparent viscosity of the suspension. The purpose of this paper is to provide a relation between the apparent viscosity of the suspension the spin rate of the particles and the E field intensity. The predictions of the model are compared to experimental data which have been obtained on a suspension of PMMA particles dispersed in a low polar dielectric liquid. The agreement between experiments and theory is rather good even if the model overestimates the viscosity decrease induced by the field.

Lemaire Elisabeth; Lobry Laurent; Peters François

2008-01-01T23:59:59.000Z

302

RELAP-7 Numerical Stabilization: Entropy Viscosity Method  

SciTech Connect (OSTI)

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

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

2014-06-01T23:59:59.000Z

303

Reduction of viscosity in suspension of swimming bacteria.  

SciTech Connect (OSTI)

Measurements of the shear viscosity in suspensions of swimming Bacillus subtilis in free-standing liquid films have revealed that the viscosity can decrease by up to a factor of 7 compared to the viscosity of the same liquid without bacteria or with nonmotile bacteria. The reduction in viscosity is observed in two complementary experiments: one studying the decay of a large vortex induced by a moving probe and another measuring the viscous torque on a rotating magnetic particle immersed in the film. The viscosity depends on the concentration and swimming speed of the bacteria.

Aranson, I. S.; Sokolov, A.; Chen, L.; Jin, Q.; Materials Science Division

2009-09-29T23:59:59.000Z

304

Bulk viscosity of QCD matter near the critical temperature  

E-Print Network [OSTI]

Kubo's formula relates bulk viscosity to the retarded Green's function of the trace of the energy-momentum tensor. Using low energy theorems of QCD for the latter we derive the formula which relates the bulk viscosity to the energy density and pressure of hot matter. We then employ the available lattice QCD data to extract the bulk viscosity as a function of temperature. We find that close to the deconfinement temperature bulk viscosity becomes large, with viscosity-to-entropy ratio zeta/s about 1.

D. Kharzeev; K. Tuchin

2007-05-29T23:59:59.000Z

305

Reduction of viscosity in suspension of swimming bacteria.  

SciTech Connect (OSTI)

Measurements of the shear viscosity in suspensions of swimming Bacillus subtilis in free-standing liquid films have revealed that the viscosity can decrease by up to a factor of 7 compared to the viscosity of the same liquid without bacteria or with nonmotile bacteria. The reduction in viscosity is observed in two complementary experiments: one studying the decay of a large vortex induced by a moving probe and another measuring the viscous torque on a rotating magnetic particle immersed in the film. The viscosity depends on the concentration and swimming speed of the bacteria.

Sokolov, A.; Aranson, I. S.; Materials Science Division; Illinois Inst. of Tech.

2009-01-01T23:59:59.000Z

306

The Role of Viscosity in TATB Hot Spot Ignition  

SciTech Connect (OSTI)

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.

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

2011-08-02T23:59:59.000Z

307

The Viscosity Bound Conjecture and Hydrodynamics of M2-Brane Theory at Finite Chemical Potential  

E-Print Network [OSTI]

Kovtun, Son and Starinets have conjectured that the viscosity to entropy density ratio $\\eta/s$ is always bounded from below by a universal multiple of $\\hbar$ i.e., $\\hbar/(4\\pi k_{B})$ for all forms of matter. Mysteriously, the proposed viscosity bound appears to be saturated in all computations done whenever a supergravity dual is available. We consider the near horizon limit of a stack of M2-branes in the grand canonical ensemble at finite R-charge densities, corresponding to non-zero angular momentum in the bulk. The corresponding four-dimensional R-charged black hole in Anti-de Sitter space provides a holographic dual in which various transport coefficients can be calculated. We find that the shear viscosity increases as soon as a background R-charge density is turned on. We numerically compute the few first corrections to the shear viscosity to entropy density ratio $\\eta/s$ and surprisingly discover that up to fourth order all corrections originating from a non-zero chemical potential vanish, leaving the bound saturated. This is a sharp signal in favor of the saturation of the viscosity bound for event horizons even in the presence of some finite background field strength. We discuss implications of this observation for the conjectured bound.

Omid Saremi

2006-01-20T23:59:59.000Z

308

Biodiesel Produced by Ethanolysis: Melting Profile, Densities, and Viscosities  

Science Journals Connector (OSTI)

Although biorenewable and sustainable ethanol is appealing and the fatty acid profiles of crambe, fodder radish, coconut, and macauba oils are proper for biodiesel production, there is little data regarding the physical properties of biodiesels produced by ethanolysis from these promising raw materials. ... Therefore, the objectives of the present work were to present the experimental densities and viscosities for biodiesels produced by ethanolysis from crambe oil (BPECr), fodder radish oil (BPEFR), coconut oil (BPEC), and macauba pulp oil (BPEMP) at temperatures up to 363.2 K, to compare the experimental data with calculated viscosities from the models proposed by Ceriani et al.(13) and Basso et al.(11) as well as with the densities calculated using the GCVOL model(14) and a systematized predictive methodology(11) based on the method proposed by Halvorsen et al.,(15) to determine, using differential scanning calorimetry, the melting profile of these four promising biofuels, and to correlate the three studied physical properties to the ethyl ester composition of each biodiesel. ... All biodiesels have low contents of polyunsaturated ethyl esters, a favorable characteristic for biodiesel because the oxidative stability decreases with increase of the unsaturation level. ...

Rodrigo C. Basso; Antônio J. A. Meirelles; Eduardo A. C. Batista

2013-09-03T23:59:59.000Z

309

Introduction Fluid/Jeans  

E-Print Network [OSTI]

Introduction Fluid/DMSC Fluid/Jeans Comments Fluid/Kinetic Hybrid Modeling of the Thermosphere;Introduction Fluid/DMSC Fluid/Jeans Comments Outline 1 Fluid/DMSC 2 Fluid/Jeans 3 Comments Justin Erwin Fluid/Kinetic Hybrid Modeling of the Thermosphere of Pluto #12;Introduction Fluid/DMSC Fluid/Jeans Comments Motivation

Johnson, Robert E.

310

Shear viscosity of the gluon plasma in the stochastic-vacuum approach  

E-Print Network [OSTI]

Shear viscosity of the gluon plasma in SU(3) YM theory is calculated nonperturbatively, within the stochastic vacuum model. The result for the ratio of the shear viscosity to the entropy density, proportional to the squared chromo-magnetic gluon condensate and the fifth power of the correlation length of the chromo-magnetic vacuum, falls off with the increase of temperature. At temperatures larger than the deconfinement critical temperature by a factor of 2, this fall-off is determined by the sixth power of the temperature-dependent strong-coupling constant and yields an asymptotic approach to the conjectured lower bound of 1/(4\\pi), achievable in {\\cal N}=4 SYM theory. As a by-product of the calculation, we find a particular form of the two-point correlation function of gluonic field strengths, which is the only one consistent with the Lorentzian shape of the shear-viscosity spectral function.

Dmitri Antonov

2009-05-20T23:59:59.000Z

311

Spinodal phase decomposition with dissipative fluid dynamics  

SciTech Connect (OSTI)

The spinodal amplification of density fluctuations is treated perturbatively within dissipative fluid dynamics including not only shear and bulk viscosity but also heat conduction, as well as a gradient term in the local pressure. The degree of spinodal amplification is calculated along specific dynamical phase trajectories and the results suggest that the effect can be greatly enhanced by tuning the collision energy so that maximum compression occurs inside the region of spinodal instability.

Randrup, J., E-mail: JRandrup@LBL.gov [Lawrence Berkeley Laboratory, Nuclear Science Division (United States)

2012-06-15T23:59:59.000Z

312

Coalescence of bubbles and drops in an outer fluid  

E-Print Network [OSTI]

When two liquid drops touch, a microscopic connecting liquid bridge forms and rapidly grows as the two drops merge into one. Whereas coalescence has been thoroughly studied when drops coalesce in vacuum or air, many important situations involve coalescence in a dense surrounding fluid, such as oil coalescence in brine. Here we study the merging of gas bubbles and liquid drops in an external fluid. Our data indicate that the flows occur over much larger length scales in the outer fluid than inside the drops themselves. Thus we find that the asymptotic early regime is always dominated by the viscosity of the drops, independent of the external fluid. A phase diagram showing the crossovers into the different possible late-time dynamics identifies a dimensionless number that signifies when the external viscosity can be important.

Joseph D. Paulsen; Rémi Carmigniani; Anerudh Kannan; Justin C. Burton; Sidney R. Nagel

2014-07-24T23:59:59.000Z

313

From Thermodynamics to the Bound on Viscosity  

E-Print Network [OSTI]

We show that the generalized second law of thermodynamics may shed much light on the mysterious Kovtun-Son-Starinets (KSS) bound on the ratio of viscosity to entropy density. In particular, we obtain the lower bound $\\eta/s +O(\\eta^3/s^3)\\geq 1/4\\pi$. Furthermore, for conformal field theories we obtain a new fundamental bound on the value of the relaxation coefficient $\\tau_{\\pi}$ of causal hydrodynamics, which has been the focus of much recent attention: $(\\tau_{\\pi}T)^2\\geq {{(\\sqrt{3}-1)}/{2\\pi^2}}$.

Shahar Hod

2009-07-07T23:59:59.000Z

314

A New Approach to Cosmological Bulk Viscosity  

E-Print Network [OSTI]

We examine the cosmological consequences of an alternative to the standard expression for bulk viscosity, one which was proposed to avoid the propagation of superluminal signals without the necessity of extending the space of variables of the theory. The Friedmann equation is derived for this case, along with an expression for the effective pressure. We find solutions for the evolution of the density of a viscous component, which differs markedly from the case of conventional Eckart theory; our model evolves toward late-time phantom-like behavior with a future singularity. Entropy production is addressed, and some similarities and differences to approaches based on the Mueller-Israel-Stewart theory are discussed.

Disconzi, Marcelo M; Scherrer, Robert J

2014-01-01T23:59:59.000Z

315

Viscosity Oscillations and Hysteresis in Dilute Emulsions  

Science Journals Connector (OSTI)

We show that the viscosity of a dilute emulsion exhibits oscillations and hysteresis as a function of the shear rate. This results from breaking up of droplets in response to the shear flow. The new phenomena we describe are generic and do not depend on a specific choice of model. The interesting dependence of the basic properties of a dilute emulsion on the shear rate results from the fact that the immersed droplets must break when the shear rate applied to the system is large enough.

Yiftah Navot and Moshe Schwartz

1997-12-15T23:59:59.000Z

316

The viscosity bound in string theory  

E-Print Network [OSTI]

The ratio of shear viscosity to entropy density $\\eta/s$ of any material in nature has been conjectured to have a lower bound of $1/4\\pi$, the famous KSS bound. We examine string theory models for evidence in favour of and against this conjecture. We show that in a broad class of models quantum corrections yield values of $\\eta/s$ just above the KSS bound. However, incorporating matter fields in the fundamental representation typically leads to violations of this bound. We also outline a program to extend AdS/CFT methods to RHIC phenomenology.

Aninda Sinha; Robert C. Myers

2009-07-27T23:59:59.000Z

317

Viscosity of the Electron Gas in Metals  

Science Journals Connector (OSTI)

With a view toward explaining measurements of ultrasonic attenuation in metals, the coefficient of shear viscosity of a free electron gas interacting with thermal phonons and local crystal inhomogeneities is computed. The methods employed are essentially those developed for the problem of electrical conductivity. By means of a variational principle, a general formal solution is obtained. The effective mean free path is found to be somewhat smaller and of a somewhat more complicated (though not qualitatively different) temperature dependence than that associated with electrical conduction. The effect of a transverse magnetic field is determined for the case when a time of relaxation exists.

M. S. Steinberg

1958-03-01T23:59:59.000Z

318

Fluid-Rock Characterization and Interactions in NMR Well Logging  

SciTech Connect (OSTI)

The objective of this project was to characterize the fluid properties and fluid-rock interactions which are needed for formation evaluation by NMR well logging. NMR well logging is finding wide use in formation evaluation. The formation parameters commonly estimated were porosity, permeability, and capillary bound water. Special cases include estimation of oil viscosity, residual oil saturation, location of oil/water contact, and interpretation on whether the hydrocarbon is oil or gas.

Hirasaki, George J.; Mohanty, Kishore K.

2003-02-10T23:59:59.000Z

319

The influence of fluid properties on the success of hydraulic fracturing operations  

SciTech Connect (OSTI)

Hydroxypropylguar based fluids are the most commonly used fluids for hydraulic fracturing. Through the addition of borate ions the polymer present in the fluid can crosslink to form a high viscosity gel. Prior to placement in the fracture the fluid is required to have a low viscosity to minimize friction losses in the tubular goods. A high viscosity fluid is required in the fracture for several reasons, primarily to suspend the proppant and to minimize fluid loss into the formation. This paper describes a new method which can be used to model the gelation reaction of crosslinking fluids. By modeling the dynamic properties of the fluid it is possible to predict the physical state of the fluid at any time during a fracturing treatment. Small amplitude oscillatory measurements are applied to fluid samples in a cone-and-plate geometry. The change in the dynamic properties with time can be fitted to a simple model which can then be used to determine the gel time for the fluid. Methods used to distinguish between the liquid and gel state are also discussed.

Power, D.J.; Boger, D.V. [Univ. of Melbourne, Victoria (Australia); Paterson, L.

1994-12-31T23:59:59.000Z

320

Clay-based geothermal drilling fluids  

SciTech Connect (OSTI)

The rheological properties of fluids based on fibrous clays such as sepiolite and attapulgite have been systematically examined under conditions similar to those of geothermal wells, i.e. at elevated temperatures and pressures in environments with concentrated brines. Attapulgite- and sepiolite-based fluids have been autoclaved at temperatures in the range from 70 to 800/sup 0/F with the addition of chlorides and hydroxides of Na, K, Ca, and Mg. The rheological properties (apparent and plastic viscosity, fluid loss, gel strength, yield point, and cake thickness) of the autoclaved fluids have been studied and correlated with the chemical and physical changes that occur in the clay minerals during the autoclaving process.

Guven, N.; Carney, L.L.; Lee, L.J.; Bernhard, R.P.

1982-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
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321

Bulk viscosity of anisotropically expanding hot QCD plasma  

SciTech Connect (OSTI)

The bulk viscosity, {zeta} and its ratio with the shear viscosity, {zeta}/{eta} have been studied in an anisotropically expanding pure glue plasma in the presence of turbulent color fields. It has been shown that the anisotropy in the momentum distribution function of gluons, which has been determined from a linearized transport equation eventually leads to the bulk viscosity. For the isotropic (equilibrium) state, a recently proposed quasiparticle model of pure SU(3) lattice QCD equation of state has been employed where the interactions are encoded in the effective fugacity. It has been argued that the interactions present in the equation of state, significantly contribute to the bulk viscosity. Its ratio with the shear viscosity is significant even at 1.5T{sub c}. Thus, one needs to take in account the effects of the bulk viscosity while studying the hydrodynamic expansion of quark-gluon plasma in the Relativistic Heavy Ion Collider and the Large Hadron Collider.

Chandra, Vinod [Department of Theoretical Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai-400005 (India)

2011-11-01T23:59:59.000Z

322

Shear viscosity and out of equilibrium dynamics  

E-Print Network [OSTI]

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 $\\eta/s$ 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 that for such small $\\alpha_s$, the gluon system is far from kinetic and chemical equilibrium, which indicates the break down of second-order hydrodynamics because of the strong noneqilibrium evolution. In addition, for large $\\alpha_s$ ($0.3-0.6$), the Israel-Stewart hydrodynamics formally breaks down at large momentum $p_T\\gtrsim 3$ GeV but is still a reasonably good approximation.

Andrej El; Zhe Xu; Carsten Greiner; Azwinndini Muronga

2008-12-15T23:59:59.000Z

323

Viscosity of Polymer Solutions: Scaling Relationships  

Science Journals Connector (OSTI)

Scaling in terms of temperature composition and molecular weight variables has practical and fundamental significance. The hydrodynamics of hard sphere systems suggest the scaling of the dimensionless ratio ? sp /(c[?]) in terms of a concentration parameter ?(M T)=1/[?]. Solutions of flexible chains indicate the appropriateness of this equation at ? and sub ? conditions but otherwise a molecular weight dependence of ? differing from that of [?] ?1 . It is possible however to define a corresponding states principle through an empirical relation between ? and M. In this case 1/??k H [?] with k H the Huggins parameter. This scheme extends in some cases up to the melt. One of us (L.A.U.) has previously considered melt viscosities of low and high molecular weight systems in terms of free volume concepts combined with theoretical liquid state results and with T g scaling the temperature. An extension to solutions yields an explicit viscosity?concentration?temperature function. Gratifying agreement with experiment can be seen. Structural changes generated by temperature concentration and pressure changes are reflected in the scaling parameters.

L. A. Utracki; R. Simha

1981-01-01T23:59:59.000Z

324

Anomalous viscosity of an expanding quark-gluon plasma  

E-Print Network [OSTI]

We argue that an expanding quark-gluon plasma has an anomalous viscosity, which arises from interactions with dynamically generated colour fields. The anomalous viscosity dominates over the collisional viscosity for large velocity gradients or weak coupling. This effect may provide an explanation for the apparent near perfect liquidity of the matter produced in nuclear collisions at RHIC without the assumption that it is a strongly coupled state.

M. Asakawa; S. A. Bass; B. Müller

2007-02-02T23:59:59.000Z

325

Surface tension in a reactive binary mixture of incompressible fluids  

E-Print Network [OSTI]

Surface tension in a reactive binary mixture of incompressible fluids Henning Struchtrup Institute with a distributed form of surface tension. The model describes chemistry, diffusion, viscosity and heat transfer tension at the front. Keywords: Binary mixtures, Surface tension, Irreversible thermodynamics, Hele

Struchtrup, Henning

326

Effect of bulk viscosity in low density, hypersonic blunt body flows  

SciTech Connect (OSTI)

A computational fluids dynamics scheme is presented to solve the unsteady Thin-Layer Navier-Stokes (TLNS) equations over a blunt body at high altitude, high Mach number atmospheric reentry flow conditions. This continuum approach is directed to low density hypersonic flows by accounting for non-zero bulk viscosity effects in near frozen flow conditions. The TLNS equations are solved over an axisymmetric body at zero incidence relative to the free stream. The time dependent axisymmetric governing equations are transformed into a computational plane, then cast into weak conservative form and solved using a first-order fully implicit scheme in time with second-order flux vector splitting for spatial derivatives. The physical domain is defined over representative sphere and sphere/cone geometries using a body-fitted clustered algebraic grid within a fixed domain (i.e., shock capturing). At the present time, nonequilibrium thermo-chemistry effects are not modeled. Catalytic wall, ionization and radiation effects are also excluded from the current analysis. However, the significant difference from previous studies is the inclusion of the capability to model non-zero bulk viscosity effects. The importance of bulk viscosity is reviewed and blunt body flow field solutions are presented to illustrate the potential contribution of this phenomena at high altitude hypersonic conditions. The current technique is compared with experimental data and other approximate continuum solutions. A variety of test cases are also presented for a wide range of free stream Mach conditions. 18 refs., 42 figs.

Rutledge, W.H. (Sandia National Labs., Albuquerque, NM (USA)); Hoffmann, K.A. (Texas Univ., Austin, TX (USA))

1991-01-01T23:59:59.000Z

327

Computing the viscosity of the QGP on the lattice  

E-Print Network [OSTI]

I review the recent progress made in calculating shear and bulk viscosity on the lattice, and discuss ways to improve the calculation.

Harvey B. Meyer

2008-05-29T23:59:59.000Z

328

On Eling-Oz formula for the holographic bulk viscosity  

E-Print Network [OSTI]

Recently Eling and Oz [1] proposed a simple formula for the bulk viscosity of holographic plasma. They argued that the formula is valid in the high temperature (near-conformal) regime, but is expected to break down at low temperatures. We point out that the formula is in perfect agreement with the previous computations of the bulk viscosity of the cascading plasma [2,3], as well as with the previous computations of the bulk viscosity of N=2^* plasma [4,5]. In the latter case it correctly reproduces the critical behaviour of the bulk viscosity in the vicinity of the critical point with the vanishing speed of sound.

Alex Buchel

2011-03-19T23:59:59.000Z

329

DWPF STARTUP FRIT VISCOSITY MEASUREMENT ROUND ROBIN RESULTS  

SciTech Connect (OSTI)

A viscosity standard is needed to replace the National Institute of Standards and Technology (NIST) glasses currently being used to calibrate viscosity measurement equipment. The current NIST glasses are either unavailable or less than ideal for calibrating equipment to measure the viscosity of high-level waste glasses. This report documents the results of a viscosity round robin study conducted on the Defense Waste Processing Facility (DWPF) startup frit. DWPF startup frit was selected because its viscosity-temperature relationship is similar to most DWPF and Hanford high-level waste glass compositions. The glass underwent grinding and blending to homogenize the large (100 lb) batch. Portions of the batch were supplied to the laboratories (named A through H) for viscosity measurements following a specified temperature schedule with a temperature range of 1150 C to 950 C and with an option to measure viscosity at lower temperatures if their equipment was capable of measuring at the higher viscosities. Results were used to fit the Vogel-Tamman-Fulcher and Arrhenius equations to viscosity as a function of temperature for the entire temperature range of 460 C through 1250 C as well as the limited temperature interval of approximately 950 C through 1250 C. The standard errors for confidence and prediction were determined for the fitted models.

Crum, Jarrod V.; Edwards, Tommy B.; Russell, Renee L.; Workman, Phyllis J.; Schweiger, Michael J.; Schumacher, Ray F.; Smith, Donald E.; Peeler, David K.; Vienna, John D.

2012-07-31T23:59:59.000Z

330

Viscosity measurements and empirical predictions for coal slags  

SciTech Connect (OSTI)

Slag viscosity in slagging coal gasifier is an important factor affecting the gasification regime and operating cost. Most of the empirical viscosity models of coal slags that are available in the literature are applicable to only limited ranges of temperature and composition. To develop a reliable slag viscosity model, additional data are needed. Slag viscosity was measured under air or reducing atmosphere (calculated pO2~1.2?10-12 atm at 1400°C) at temperatures in the range of 1150-1550°C on 63 statistically designed slags, including 5 actual coal slag compositions and 4 validation slag compositions. The Arrhenius equation, with Arrhenius coefficients A = constant and B expressed as linear function of mass fractions of nine major components was used to fit the viscosity/temperature data. This Arrhenius relationship represents the viscosity–temperature relationship of tested slags reasonably well, = 0.981 (reducing atmosphere) and = 0.974 (air atmosphere). The validation of the model with four randomly selected slags (two from the SciGlass database and two from experimental design) indicated an accurately measured viscosity-temperature data and a fairly good predictive performance of slag viscosity models over designed compositions. The capability of the developed model to predict the viscosity of coal slags under reducing atmosphere was found to be a superior to a number of the most commonly used empirical models in the literature that are based on simplified oxide melts and British or Australian coal ash slags.

Matyas, Josef; Sundaram, S. K.; Rodriguez, Carmen P.; Heredia-Langner, Alejandro; Arrigoni, Benjamin M.

2009-10-25T23:59:59.000Z

331

Relation between viscosity and stability for heavy oil emulsions.  

E-Print Network [OSTI]

??The relation between viscosity and stability has been hics. found by investigating the effect of surfactant concentration on emulsion stability. Based on the Bingham plastic… (more)

Ye, Sherry Qianwen

2012-01-01T23:59:59.000Z

332

Fluid inflation  

SciTech Connect (OSTI)

In this work we present an inflationary mechanism based on fluid dynamics. Starting with the action for a single barotropic perfect fluid, we outline the procedure to calculate the power spectrum and the bispectrum of the curvature perturbation. It is shown that a perfect barotropic fluid naturally gives rise to a non-attractor inflationary universe in which the curvature perturbation is not frozen on super-horizon scales. We show that a scale-invariant power spectrum can be obtained with the local non-Gaussianity parameter f{sub NL} = 5/2.

Chen, X. [Centre for Theoretical Cosmology, DAMTP, University of Cambridge, Cambridge CB3 0WA (United Kingdom); Firouzjahi, H. [School of Astronomy, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Namjoo, M.H. [School of Physics, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Sasaki, M., E-mail: x.chen@damtp.cam.ac.uk, E-mail: firouz@ipm.ir, E-mail: mh.namjoo@ipm.ir, E-mail: misao@yukawa.kyoto-u.ac.jp [Yukawa Institute for theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)

2013-09-01T23:59:59.000Z

333

Review of Helium and Xenon Pure Component and Mixture Transport Properties and Recommendation of Estimating Approach for Project Prometheus (Viscosity and Thermal Conductivity)  

SciTech Connect (OSTI)

The selected configuration for the Project Prometheus Space Nuclear Power Plant was a direct coupling of Brayton energy conversion loop(s) to a single reactor heat source through the gas coolant/working fluid. A mixture of helium (He) and xenon (Xe) gas was assumed as the coolant/working fluid. Helium has superior thermal conductivity while xenon is added to increase the gas atomic weight to benefit turbomachinery design. Both elements have the advantage of being non-reactive. HeXe transport properties (viscosity and thermal conductivity) were needed to calculate pressure drops and heat transfer rates. HeXe mixture data are limited, necessitating the use of semi-empirical correlations to calculate mixture properties. Several approaches are available. Pure component properties are generally required in the mixture calculations. While analytical methods are available to estimate pure component properties, adequate helium and xenon pure component data are available. This paper compares the sources of pure component data and the approaches to calculate mixture properties. Calculated mixture properties are compared to the limited mixture data and approaches are recommended to calculate both pure component and mixture properties. Given the limited quantity of HeXe mixture data (all at one atmosphere), additional testing may have been required for Project Prometheus to augment the existing data and confirm the selection of mixture property calculation methods.

Haire, Melissa A.; Vargo, David D. [Bechtel Bettis, Inc., Bettis Atomic Power Laboratory, P.O. Box 79, West Mifflin, PA 15122 (United States)

2007-01-30T23:59:59.000Z

334

Viscosity of ?-pinene secondary organic material and implications for particle growth and reactivity  

SciTech Connect (OSTI)

Particles composed of secondary organic material (SOM) are abundant in the lower troposphere and play important roles in climate, air quality, and health. The viscosity of these particles is a fundamental property that is presently poorly quantified for conditions relevant to the lower troposphere. Using two new techniques, namely a bead-mobility technique and a poke-flow technique, in conjunction with simulations of fluid flow, we measure the viscosity of the watersoluble component of SOM produced by ?-pinene ozonolysis. The viscosity is comparable to that of honey at 90% relative humidity (RH), comparable to that of peanut butter at 70% RH and greater than or comparable to that of bitumen for ? 30% RH, implying that the studied SOM ranges from liquid to semisolid/solid at ambient relative humidities. With the Stokes-Einstein relation, the measured viscosities further imply that the growth and evaporation of SOM by the exchange of organic molecules between the gas and condensed phases may be confined to the surface region when RH ? 30%, suggesting the importance of an adsorption-type mechanism for partitioning in this regime. By comparison, for RH ? 70% partitioning of organic molecules may effectively occur by an absorption mechanism throughout the bulk of the particle. Finally, the net uptake rates of semi-reactive atmospheric oxidants such as O3 are expected to decrease by two to five orders of magnitude for a change in RH from 90% to ? 30% RH, with possible implications for the rates of chemical aging of SOM particles in the atmosphere.

Renbaum-Wolff, Lindsay; Grayson, James W.; Bateman, Adam P.; Kuwata, Mikinori; Sellier, Mathieu; Murray, Benjamin J.; Shilling, John E.; Martin, Scot T.; Bertram, Allan K.

2013-05-14T23:59:59.000Z

335

Jet momentum balance independent of shear viscosity  

E-Print Network [OSTI]

Jet momentum balance measurements, such as those recently performed by the CMS collaboration, provide an opportunity to quantify the energy transferred from a parton shower to the underlying medium in heavy-ion collisions. Specifically, I argue that the Cooper-Frye freezeout distribution associated with the energy and momentum deposited by the parton shower is controlled to a significant extent by the distribution of the underlying bulk matter and independent of the details of how deposited energy is redistributed in the medium, which is largely determined by transport coefficients such as shear viscosity. Thus by matching the distribution of momentum associated with the secondary jet in such measurements to the thermal distribution of the underlying medium, one can obtain a model independent estimate on the amount of parton shower energy deposited.

R. B. Neufeld

2011-08-31T23:59:59.000Z

336

On bulk viscosity and moduli decay  

E-Print Network [OSTI]

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

M. Laine

2010-07-15T23:59:59.000Z

337

Hybrid viscosity and the magnetoviscous instability in hot, collisionless accretion disks  

E-Print Network [OSTI]

We aim to illustrate the role of hot protons in enhancing the magnetorotational instability (MRI) via the ``hybrid'' viscosity, which is due to the redirection of protons interacting with static magnetic field perturbations, and to establish that it is the only relevant mechanism in this situation. It has recently been shown by Balbus \\cite{PBM1} and Islam & Balbus \\cite{PBM11} using a fluid approach that viscous momentum transport is key to the development of the MRI in accretion disks for a wide range of parameters. However, their results do not apply in hot, advection-dominated disks, which are collisionless. We develop a fluid picture using the hybrid viscosity mechanism, that applies in the collisionless limit. We demonstrate that viscous effects arising from this mechanism can significantly enhance the growth of the MRI as long as the plasma $\\beta \\gapprox 80$. Our results facilitate for the first time a direct comparison between the MHD and quasi-kinetic treatments of the magnetoviscous instability in hot, collisionless disks.

Prasad Subramanian; Peter A. Becker; Menas Kafatos

2008-02-25T23:59:59.000Z

338

Leptonic contribution to the bulk viscosity of nuclear matter  

SciTech Connect (OSTI)

For {beta}-equilibrated nuclear matter we estimate the contribution to the bulk viscosity from purely leptonic processes, namely the conversion of electrons to and from muons. For oscillation frequencies in the kilohertz range, we find that this process provides the dominant contribution to the bulk viscosity when the temperature is well below the critical temperature for superconductivity or superfluidity of the nuclear matter.

Alford, Mark G.; Good, Gerald [Physics Department, Washington University, St. Louis, Missouri 63130 (United States)

2010-11-15T23:59:59.000Z

339

1 Visco-plastic rheology 1.1 Effective viscosity  

E-Print Network [OSTI]

1 Visco-plastic rheology 1.1 Effective viscosity Rheology specifies the relationship between viscosity eff, = 2eff , (2) which includes viscous and plastic components, 1 eff = 1 visc + 1 plast . (3) Also the strain rate tensor can be split into viscous and plastic part, = visc + plast , (4) where

Cerveny, Vlastislav

340

Viscosity of concentrated suspensions of sphere/rod mixtures  

SciTech Connect (OSTI)

This paper discusses the viscosity of concentrated suspensions of sphere/rod mixtures by adopting the Thomas relations for spheres and Milliken`s for randomly oriented rods with aspect ratio of 20. The relative viscosity of a mixed suspension may now be calculated for any combination of rods (of aspect ratio 20) and spheres.

Mor, R.; Gottlieb, M. [Ben-Gurion Univ. of the Negev, Beersheba (Israel). Dept. of Chemical Engineering; Graham, A.L. [Los Alamos National Lab., NM (United States); Mondy, L.A.

1996-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Viscosity Solutions In this lecture we take a glimpse of the viscosity solution theory for linear and nonlinear PDEs. From our  

E-Print Network [OSTI]

Oct. 1 0 Viscosity Solutions In this lecture we take a glimpse of the viscosity solution theory "viscosity solutions", and a quite complete regularity theory which paral- lels those we have seen has been a few example of the equations that can be dealt with using the idea of viscosity solutions. Example 1

Yu, Xinwei

342

J. Fluid Mech. (2009), vol. 626, pp. 211240. c 2009 Cambridge University Press doi:10.1017/S0022112009005795 Printed in the United Kingdom  

E-Print Network [OSTI]

geometries. Particular attention is given to the influence of the fluid viscosity on the evolution of the sheet and its bounding rim. In both geometries, after a transient that depends on the sheet viscosity rupture can be either desirable, as in spray formation (e.g. Pomeau & Villermaux 2006), or undesirable

Bush, John W.M.

343

Collision of viscoelastic jets and the formation of fluid webs Erik Miller, Beau Gibson, Erik McWilliams, and Jonathan P. Rothsteina  

E-Print Network [OSTI]

and industrial applications such as agrochemical spraying, spray coating, and ink jet printing, little work has by the extensional viscosity, E, and the surface tension, , of the fluid. For polymeric or worm-like micelle solutions, the shear and extensional viscosities can be strong functions of the flow kinematics, the rate

Rothstein, Jonathan

344

VISCOSITY OF AQUEOUS SODIUM CHLORIDE SOLUTIONS FROM 0 - 150oC  

E-Print Network [OSTI]

A. , Fabuss, B.M. , "Viscosities of Binary Aqueous Solutionsof Pressure on the Viscosity of Aqueous NaCl Solutions inF.A. , Kestin, J. , "The Viscosity of NaCl and KCl Solutions

Ozbek, H.

2010-01-01T23:59:59.000Z

345

Transition to Turbulence in Shear-Thinning Fluids  

E-Print Network [OSTI]

energy DNS direct numerical simulation RCA right coronary arteries WSS wall shear stress z? vorticity in the z direction ?t time scale of dissipation due to viscosity iu total velocity u total velocity in the x direction v total velocity in the y... viscosity K fluid consistency divided by density n power law index xL domain length in the x direction v yL domain length in the y direction Lz domain length in the z direction D height of the half channel ??? velocity field of the mature...

Zhen, Ni

2014-04-23T23:59:59.000Z

346

A Brief Review of Viscosity Models for Slag in Coal Gasification  

SciTech Connect (OSTI)

Many researchers have defined the phenomenon of 'slagging' as the deposition of ash in the radiative section of a boiler, while 'fouling' refers to the deposition of ash in the convective-pass region. Among the important parameters affecting ash deposition that need to be studied are ash chemistry, its transport, deposit growth, and strength development; removability of the ash deposit; heat transfer mechanisms; and the mode of operation for boilers. The heat transfer at the walls of a combustor depends on many parameters including ash deposition. This depends on the processes or parameters controlling the impact efficiency and the sticking efficiency. For a slagging combustor or furnace, however, the temperatures are so high that much of the coal particles are melted and the molten layer, in turn, captures more particles as it flows. The main problems with ash deposition are reduced heat transfer in the boiler and corrosion of the tubes. Common ways of dealing with these issues are soot blowing and wall blowing on a routine basis; however, unexpected or uncontrolled depositions can also complicate the situation, and there are always locations inaccessible to the use of such techniques. Studies have indicated that slag viscosity must be within a certain range of temperatures for tapping and the membrane wall to be accessible, for example, between 1300 C and 1500 C, the viscosity is approximately 25 Pa {center_dot} s. As the operating temperature decreases, the slag cools and solid crystals begin to form. In such cases the slag should be regarded as a non-Newtonian suspension, consisting of liquid silicate and crystals. A better understanding of the rheological properties of the slag, such as yield stress and shear-thinning, are critical in determining the optimum operating conditions. To develop an accurate heat transfer model in any type of coal combustion or gasification process, the heat transfer and to some extent the rheological properties of ash and slag, especially in high-temperature environments need to be understood and properly modeled. The viscosity of slag and the thermal conductivity of ash deposits are among two of the most important constitutive parameters that need to be studied. The accurate formulation or representations of the (transport) properties of coal (and biomass for co-firing cases) present a special challenge of modeling efforts in computational fluid dynamics applications. In this report, we first provide a brief review of the various approaches taken by different researchers in formulating or obtaining a slag viscosity model. In general, these models are based on experiments. Since slag behaves as a non-linear fluid, we discuss the constitutive modeling of slag and the important parameters that must be studied.

Massoudi, Mehrdad; Wang, Ping

2011-11-01T23:59:59.000Z

347

The viscosity of liquids (a) Normal octanol at atmospheric pressure (b) An equipment for high pressures.  

E-Print Network [OSTI]

??Theories of Liquid Viscosity lead to equations giving the variation of the viscosity with temperature and pressure, but give poor agreement with experimental values, particularly… (more)

De Verteuil, Georges Francois

2012-01-01T23:59:59.000Z

348

Static and Dynamic Viscosity of a Single Layer Dusty Plasma  

SciTech Connect (OSTI)

We measured the static and dynamic (complex) shear viscosity of a single layer complex plasma by applying, respectively, a stationary and a periodically modulated shear stress induced by the light pressure of manipulating laser beams. Under static conditions the shear viscosity reproduced the numerically predicted shear rate dependence, the so called shear-thinning effect. Under oscillating shear both the magnitude and the ratio of the dissipative and elastic contributions to the complex viscosity show strong frequency dependence. Accompanying molecular dynamics simulations explain and support the experimental observations.

Hartmann, Peter [Research Institute for Solid State Physics and Optics of the Hungarian Academy of Sciences, P.O.B. 49, H-1525 Budapest (Hungary); Center for Astrophysics, Space Physics and Engineering Research (CASPER), One Bear Place 97310, Baylor University, Waco, TX 76798 (United States); Sandor, Mate Cs.; Kovacs, Aniko; Donko, Zoltan [Research Institute for Solid State Physics and Optics of the Hungarian Academy of Sciences, P.O.B. 49, H-1525 Budapest (Hungary)

2011-11-29T23:59:59.000Z

349

Bulk viscosity, chemical equilibration and flow at RHIC  

E-Print Network [OSTI]

We study the effects of bulk viscosity on p_T spectra and elliptic flow in heavy ion collisions at RHIC. We argue that direct effect of the bulk viscosity on the evolution of the velocity field is small, but corrections to the freezeout distributions can be significant. These effects are dominated by chemical non-equilibration in the hadronic phase. We show that a non-zero bulk viscosity in the range $\\zeta/s \\lsim 0.05$ improves the description of spectra and flow at RHIC.

Thomas Schaefer; Kevin Dusling

2012-10-15T23:59:59.000Z

350

Bulk Viscosity driven clusterization of quark-gluon plasma and early freeze-out in relativistic heavy-ion collisions  

E-Print Network [OSTI]

We introduce a new scenario for heavy ion collisions that could solve the lingering problems associated with the so-called HBT puzzle. We postulate that the system starts expansion as the perfect quark-gluon fluid but close to freeze-out it splits into clusters, due to a sharp rise of bulk viscosity in the vicinity of the hadronization transition. We then argue that the characteristic cluster size is determined by the viscosity coefficient and the expansion rate. Typically it is much smaller and independent of the total system volume. These clusters maintain the pre-existing outward-going flow, as a spray of droplets, but develop no flow of their own, and hadronize by evaporation. We provide an ansatz for converting the hydrodynamic output into clusters.

Giorgio Torrieri; Boris Tomasik; Igor Mishustin

2008-02-26T23:59:59.000Z

351

Bulk Viscosity driven clusterization of quark-gluon plasma and early freeze-out in relativistic heavy-ion collisions  

E-Print Network [OSTI]

We introduce a new scenario for heavy ion collisions that could solve the lingering problems associated with the so-called HBT puzzle. We postulate that the system starts expansion as the perfect quark-gluon fluid but close to freeze-out it splits into clusters, due to a sharp rise of bulk viscosity in the vicinity of the hadronization transition. We then argue that the characteristic cluster size is determined by the viscosity coefficient and the expansion rate. Typically it is much smaller and independent of the total system volume. These clusters maintain the pre-existing outward-going flow, as a spray of droplets, but develop no flow of their own, and hadronize by evaporation. We provide an ansatz for converting the hydrodynamic output into clusters.

Torrieri, G; Mishustin, I

2007-01-01T23:59:59.000Z

352

Hall viscosity and angular momentum in gapless holographic models  

E-Print Network [OSTI]

We use the holographic approach to compare the Hall viscosity ?[subscript H] and the angular momentum density J in gapless systems in 2 + 1 dimensions at finite temperature. We start with a conformal fixed point and turn ...

Liu, Hong

353

Gas Viscosity at High Pressure and High Temperature  

E-Print Network [OSTI]

. Although viscosity of some pure components such as methane, ethane, propane, butane, nitrogen, carbon dioxide and binary mixtures of these components at low-intermediate pressure and temperature had been studied intensively and been understood thoroughly...

Ling, Kegang

2012-02-14T23:59:59.000Z

354

EFFECT OF GLASS COMPOSITION ON ACTIVATION ENERGY OF VISCOSITY...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

EFFECT OF GLASS COMPOSITION ON ACTIVATION ENERGY OF VISCOSITY IN GLASS-MELTING-TEMPERATURE RANGE Sang-Soo Han (1) , Pavel Hrma (1,2) (1) Division of Advanced Nuclear Engineering,...

355

Bulk viscosity and the conformal anomaly in the pion gas  

E-Print Network [OSTI]

We calculate the bulk viscosity of the massive pion gas within Unitarized Chiral Perturbation Theory. We obtain a low temperature peak arising from explicit conformal breaking due to the pion mass and another peak near the critical temperature, dominated by the conformal anomaly through gluon condensate terms. The correlation between bulk viscosity and conformal breaking supports a recent QCD proposal. We discuss the role of resonances, heavier states and large-$N_c$ counting.

D. Fernandez-Fraile; A. Gomez Nicola

2008-09-26T23:59:59.000Z

356

Viscosity and boost invariance at RHIC and LHC  

E-Print Network [OSTI]

We consider the longitudinal hydrodynamic evolution of the fireball created in a relativistic heavy-ion collision. Nonzero shear viscosity reduces the colling rate of the system and hinders the acceleration of the longitudinal flow. As a consequence, the initial energy density needed to reproduce the experimental data at RHIC energies is significantly reduced. At LHC energies, we expect that shear viscosity helps to conserve a Bjorken plateau in the rapidity distributions during the expansion.

Piotr Bozek

2008-03-31T23:59:59.000Z

357

Oxygen consumption by asphalt films and resulting viscosity changes  

E-Print Network [OSTI]

OXYGEN CONSUMPTION BY ASPHALT FILNS AND RESULTING VISCOSITY CHANGES A Thesis by FRANK LEE CARTER, JR. Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE... Nay 1965 Major Subject: Chemistry OXYGEN CONSUMPTION BY ASPHALT FILMS AND RESULTING VISCOSITY CHANGES A Thesis by FRANK LEE CARTER, JR. Approved as to style and content by: (Chairm of Committee) (H o Depa ( mb ) (Membe May 1965...

Carter, Frank Lee

2012-06-07T23:59:59.000Z

358

Coefficients of the second viscosity in bulk liquid helium  

Science Journals Connector (OSTI)

The coefficients of the second viscosity in bulk liquid helium are evaluated explicitly as a function of temperature via interactions between the anomalous excitation spectrums. The four coefficients of the second viscosity exhibit a T-1 dependence at low temperatures (well below 0.6 K), which is due to three-phonon processes originating from the anomalous dispersion at very low momenta and temperatures.

Chung-In Um; Chul-Won Jun; Thomas F. George

1992-09-01T23:59:59.000Z

359

Shear-viscosity to entropy-density ratio from giant dipole resonances in hot nuclei  

SciTech Connect (OSTI)

The Green-Kubo relation and fluctuation-dissipation theorem are employed to calculate the shear viscosity {eta} of a finite hot nucleus directly from the width and energy of the giant dipole resonance (GDR) of this nucleus. The ratio {eta}/s of shear viscosity {eta} to entropy density s is extracted from the experimental systematics of the GDR in copper, tin, and lead isotopes at finite temperature T. These empirical results are then compared with the predictions by several independent models as well as with almost model-independent estimations. Based on these results, it is concluded that the ratio {eta}/s in medium and heavy nuclei decreases with increasing temperature T to reach (1.3--4)x({h_bar}/2{pi})/(4{pi}k{sub B}) at T=5 MeV.

Nguyen Dinh Dang [Theoretical Nuclear Physics Laboratory, RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako City, 351-0198 Saitama (Japan) and Institute for Nuclear Science and Technique, Hanoi (Viet Nam)

2011-09-15T23:59:59.000Z

360

Shear viscosity of hot nuclear matter by the mean free path method  

E-Print Network [OSTI]

The shear viscosity of hot nuclear matter is investigated by using the mean free path method within the framework of IQMD model. Finite size nuclear sources at different density and temperature are initialized based on the Fermi-Dirac distribution. The results show that shear viscosity to entropy density ratio decreases with the increase of temperature and tends toward a constant value for $\\rho\\sim\\rho_0$, which is consistent with the previous studies on nuclear matter formed during heavy-ion collisions. At $\\rho\\sim\\frac{1}{2}\\rho_0$, a minimum of $\\eta/s$ is seen at around $T=10$ MeV and a maximum of the multiplicity of intermediate mass fragment ($M_{\\text{IMF}}$) is also observed at the same temperature which is an indication of the liquid-gas phase transition.

D. Q. Fang; Y. G. Ma; C. L. Zhou

2014-04-17T23:59:59.000Z

Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Shear viscosity of hot nuclear matter by the mean free path method  

E-Print Network [OSTI]

The shear viscosity of hot nuclear matter is investigated by using the mean free path method within the framework of IQMD model. Finite size nuclear sources at different density and temperature are initialized based on the Fermi-Dirac distribution. The results show that shear viscosity to entropy density ratio decreases with the increase of temperature and tends toward a constant value for $\\rho\\sim\\rho_0$, which is consistent with the previous studies on nuclear matter formed during heavy-ion collisions. At $\\rho\\sim\\frac{1}{2}\\rho_0$, a minimum of $\\eta/s$ is seen at around $T=10$ MeV and a maximum of the multiplicity of intermediate mass fragment ($M_{\\text{IMF}}$) is also observed at the same temperature which is an indication of the liquid-gas phase transition.

Fang, D Q; Zhou, C L

2014-01-01T23:59:59.000Z

362

Use of ammonia to reduce the viscosity of bottoms streams produced in hydroconversion processes  

DOE Patents [OSTI]

Coal, petroleum residuum and similar carbonaceous feed materials are subjected to hydroconversion in the presence of molecular hydrogen to produce a hydroconversion effluent which is then subjected to one or more separation steps to remove lower molecular weight liquids and produce a heavy bottoms stream containing high molecular weight liquids and unconverted carbonaceous material. The viscosity of the bottoms streams produced in the separation step or steps is prevented from increasing rapidly by treating the feed to the separation step or steps with ammonia gas prior to or during the separation step or steps. The viscosity of the heavy bottoms stream produced in the final separation step is also controlled by treating these bottoms with ammonia gas. In a preferred embodiment of the invention, the effluent from the hydroconversion reactor is subjected to an atmospheric distillation followed by a vacuum distillation and the feeds to these distillations are contacted with ammonia during the distillations.

Zaczepinski, Sioma (Houston, TX); Billimoria, Rustom M. (Houston, TX); Tao, Frank (Baytown, TX); Lington, Christopher G. (Houston, TX); Plumlee, Karl W. (Baytown, TX)

1984-01-01T23:59:59.000Z

363

Stable Numerical Approximation of Two-Phase Flow with a Boussinesq--Scriven Surface Fluid  

E-Print Network [OSTI]

We consider two-phase Navier--Stokes flow with a Boussinesq--Scriven surface fluid. In such a fluid the rheological behaviour at the interface includes surface viscosity effects, in addition to the classical surface tension effects. We introduce and analyze parametric finite element approximations, and show, in particular, stability results for semi-discrete versions of the methods, by demonstrating that a free energy inequality also holds on the discrete level. We perform several numerical simulations for various scenarios in two and three dimensions, which illustrate the effects of the surface viscosity.

Barrett, John W; Nürnberg, Robert

2014-01-01T23:59:59.000Z

364

Increasing Knowledge Increasing Knowledge 29  

E-Print Network [OSTI]

28 Increasing Knowledge Increasing Knowledge 29 Expanding Leadership 36 Building Partnerships 43 the world. The challenges ahead are large, but WSP is preparing to meet them by increasing knowledge, expanding leadership, building partnerships, and seeking solutions. #12;29 Increasing Knowledge Increasing

Fay, Noah

365

Square root singularity in the viscosity of neutral colloidal suspensions at large frequencies  

E-Print Network [OSTI]

The asymptotic frequency $\\omega$, dependence of the dynamic viscosity of neutral hard sphere colloidal suspensions is shown to be of the form $\\eta_0 A(\\phi) (\\omega \\tau_P)^{-1/2}$, where $A(\\phi)$ has been determined as a function of the volume fraction $\\phi$, for all concentrations in the fluid range, $\\eta_0$ is the solvent viscosity and $\\tau_P$ the P\\'{e}clet time. For a soft potential it is shown that, to leading order steepness, the asymptotic behavior is the same as that for the hard sphere potential and a condition for the cross-over behavior to $1/\\omega \\tau_P$ is given. Our result for the hard sphere potential generalizes a result of Cichocki and Felderhof obtained at low concentrations and agrees well with the experiments of van der Werff et al, if the usual Stokes-Einstein diffusion coefficient $D_0$ in the Smoluchowski operator is consistently replaced by the short-time self diffusion coefficient $D_s(\\phi)$ for non-dilute colloidal suspensions.

R. Verberg; I. M. de Schepper; M. J. Feigenbaum; E. G. D. Cohen

1997-01-17T23:59:59.000Z

366

Viscosity of liquid He-4 and quantum of circulation: Why and how are they related?  

E-Print Network [OSTI]

The relationship between the apparently unrelated physical quantities -- kinematic viscosity of liquid He-4, $\

V. S. L'vov; L. Skrbek

2011-02-16T23:59:59.000Z

367

Viscosity of semi-dilute polymer solutions M. Adam and M. Delsanti  

E-Print Network [OSTI]

549 Viscosity of semi-dilute polymer solutions M. Adam and M. Delsanti Laboratoire Léon viscosity measurements on semi-dilute solutions (c* c 10 %). The viscosity variation is independent to the solvent viscosity. With concentration, the following variations were observed : 2014 for PIB-toluene, ~r

Paris-Sud XI, Université de

368

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

SciTech Connect (OSTI)

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.

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

1995-12-31T23:59:59.000Z

369

Two-dimensional nanostructured Y{sub 2}O{sub 3} particles for viscosity modification  

SciTech Connect (OSTI)

Nanoparticle additives have been shown to improve the mechanical and transport phenomena of various liquids; however, little has been done to try and explain the rheological modifications provided from such modifications from a theoretical standpoint. Here, we report a non-Einstein-like reduction of viscosity of mineral oil with the utilization of yttrium oxide nanosheet additives. Experimental results, coupled with generalized smoothed-particle hydrodynamics simulations, provide insight into the mechanism behind this reduction of fluid shear stress. The ordered inclination of these two-dimensional nanoparticle additives markedly improves the lubricating properties of the mineral oil, ultimately reducing the friction, and providing a way in designing and understanding next generation of lubricants.

He, Xingliang; Xiao, Huaping; Liang, Hong, E-mail: hliang@tamu.edu [Department of Mechanical Engineering, Texas A and M University, College Station, Texas 77843-3123 (United States); Kyle, Jonathan P.; Terrell, Elon J. [Department of Mechanical Engineering, Columbia University, New York, New York 10027 (United States)

2014-04-21T23:59:59.000Z

370

Viscosity Determination of Molten Ash from Low-Grade US Coals  

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

In entrained slagging gasifiers, the fluidity of the molten ash is a critical factor for process control since it affects slag formation, the capture of inorganic constituents, refractory wear, and slag drainage along the gasification chamber walls. The use of western coal, or mixtures of eastern and western coals as gasifier feedstock, is likely to occur as western coals become available and technological issues that hinder their use are being resolved. In the present work, the viscosity of synthetic slags with ash chemistries simulating the western U.S. coals, was experimentally measured at a Po2?=?10- 8 atm in the temperature range of 1773–1573 K (1500–1300 °C) using a rotating-bob viscometer. Alumina spindles and containment crucibles of both alumina and zirconia were used. Crystallization studies of this slag using a confocal scanning laser microscope found that a (Mg,Fe)Al2O4-based spinel precipitated at temperatures below 1723 K (1450 °C), and this agreed with FactSage equilibrium phase prediction. The same spinels were observed in the post-viscometry experiment slags when ZrO2 crucibles were used and assumed to be in equilibrium with the slag at the higher temperatures. Zirconia dissolution resulted in a slight increase in the solid fraction present in slags at lower temperatures, compared to spinel fraction. Crystal precipitation changed the apparent activation energy and required a longer stabilization times for viscosity measurements. The viscosity results were used in predictive equations based on Veytsman and Einstein's models, with critical nucleation temperatures and the solid fraction calculated with FactSage. In the simulated eastern/western coal feedstock blends based on ash compositions, the fractions of the solid precipitates were also calculated using the thermodynamic program FactSage for each blend composition, and the plastic viscosity of each eastern/western coal slag blend was predicted using Veytsman's model and compared to available experimental data.

Zhu, Jingxi [National Energy Technology Laboratory (NETL), Pittsburgh, PA, and Morgantown, WV (United States); URS Corp., Albany, OR (United States); Nakano, Jinichiro [National Energy Technology Laboratory (NETL), Pittsburgh, PA, and Morgantown, WV (United States); URS Corp., Albany, OR (United States); Kaneko, Tetsuya Kenneth [National Energy Technology Laboratory (NETL), Pittsburgh, PA, and Morgantown, WV (United States); Carnegie Mellon Univ., Pittsburgh, PA (United States); Mu, Haoyuan [Carnegie Mellon Univ., Pittsburgh, PA (United States); Bennett, James P. [National Energy Technology Laboratory (NETL), Pittsburgh, PA, and Morgantown, WV (United States); Kwong, Kyei-Sing [National Energy Technology Laboratory (NETL), Pittsburgh, PA, and Morgantown, WV (United States); Rozelle, Peter [US Dept. of Energy, Washington, DC (United States). Office of Clean Energy Systems; Sridhar, Seetharaman [National Energy Technology Laboratory (NETL), Pittsburgh, PA, and Morgantown, WV (United States); Carnegie Mellon Univ., Pittsburgh, PA (United States)

2011-10-01T23:59:59.000Z

371

Viscosity and scale invariance in the unitary Fermi gas  

E-Print Network [OSTI]

We compute the shear viscosity of the unitary Fermi gas above the superfluid transition temperature, using a diagrammatic technique that starts from the exact Kubo formula. The formalism obeys a Ward identity associated with scale invariance which guarantees that the bulk viscosity vanishes identically. For the shear viscosity, vertex corrections and the associated Aslamazov-Larkin contributions are shown to be crucial to reproduce the full Boltzmann equation result in the high-temperature, low fugacity limit. The frequency dependent shear viscosity $\\eta(\\omega)$ exhibits a Drude-like transport peak and a power-law tail at large frequencies which is proportional to the Tan contact. The weight in the transport peak is given by the equilibrium pressure, in agreement with a sum rule due to Taylor and Randeria. Near the superfluid transition the peak width is of the order of $0.5 T_F$, thus invalidating a quasiparticle description. The ratio $\\eta/s$ between the static shear viscosity and the entropy density exhibits a minimum near the superfluid transition temperature whose value is larger than the string theory bound $\\hbar/(4\\pi k_B)$ by a factor of about seven.

Tilman Enss; Rudolf Haussmann; Wilhelm Zwerger

2010-07-30T23:59:59.000Z

372

Dark goo: bulk viscosity as an alternative to dark energy  

SciTech Connect (OSTI)

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

Gagnon, Jean-Sebastien [Technische Universität Darmstadt, Schlossgartenstrasse 2, 64289, Darmstadt (Germany); Lesgourgues, Julien, E-mail: jean-sebastien.gagnon@physik.tu-darmstadt.de, E-mail: julien.lesgourgues@cern.ch [École Polytechnique Fédérale de Lausanne, CH-1015, Lausanne (Switzerland)

2011-09-01T23:59:59.000Z

373

Viscosity and scale invariance in the unitary Fermi gas  

SciTech Connect (OSTI)

We compute the shear viscosity of the unitary Fermi gas above the superfluid transition temperature, using a diagrammatic technique that starts from the exact Kubo formula. The formalism obeys a Ward identity associated with scale invariance which guarantees that the bulk viscosity vanishes identically. For the shear viscosity, vertex corrections and the associated Aslamazov-Larkin contributions are shown to be crucial to reproduce the full Boltzmann equation result in the high-temperature, low fugacity limit. The frequency dependent shear viscosity {eta}({omega}) exhibits a Drude-like transport peak and a power-law tail at large frequencies which is proportional to the Tan contact. The weight in the transport peak is given by the equilibrium pressure, in agreement with a sum rule due to Taylor and Randeria. Near the superfluid transition the peak width is of the order of 0.5T{sub F}, thus invalidating a quasiparticle description. The ratio {eta}/s between the static shear viscosity and the entropy density exhibits a minimum near the superfluid transition temperature whose value is larger than the string theory bound h/(4{pi}k{sub B}) by a factor of about seven.

Enss, Tilman, E-mail: Tilman.Enss@ph.tum.de [Technische Universitaet Muenchen, James-Franck-Strasse, D-85747 Garching (Germany); Haussmann, Rudolf [Fachbereich Physik, Universitaet Konstanz, D-78457 Konstanz (Germany); Zwerger, Wilhelm [Technische Universitaet Muenchen, James-Franck-Strasse, D-85747 Garching (Germany)

2011-03-15T23:59:59.000Z

374

Decreased Hematocrit-To-Viscosity Ratio and Increased Lactate Dehydrogenase Level in Patients with Sickle Cell  

E-Print Network [OSTI]

with Sickle Cell Anemia and Recurrent Leg Ulcers Philippe Connes1,2,3* , Yann Lamarre1,2 , Marie-à-Pitre, Guadeloupe Abstract Leg ulcer is a disabling complication in patients with sickle cell anemia (SCA Dehydrogenase Level in Patients with Sickle Cell Anemia and Recurrent Leg Ulcers. PLoS ONE 8(11): e79680. doi:10

Paris-Sud XI, Université de

375

Study of shear-driven unsteady flows of a fluid with a pressure dependent viscosity  

E-Print Network [OSTI]

In this thesis, the seminal work of Stokes concerning the ow of a Navier-Stokesuid due to a suddenly accelerated or oscillating plate and the ow due to torsionaloscillations of an innitely long rod in a Navier-Stokes uid is extended to a uid...

Srinivasan, Shriram

2009-05-15T23:59:59.000Z

376

Comparative study of the fluid viscosity in tarsal hairy attachment systems of flies and beetles  

Science Journals Connector (OSTI)

...some critical height h c, the pressure inside the capillary bridge becomes (mathematically...5 microm. Below h c, the secretion...inside the capillary bridge becomes negative...creates a capillary bridge between two stiff...separated by distance h. The liquid has contact...

2014-01-01T23:59:59.000Z

377

Effectiveness of continuous hot-fluid stimulation of high viscosity oil wells  

E-Print Network [OSTI]

TABLE OF CONTENTS LIST OF TABLES . LIST OF FIGURES INTRODUCTION . PROCEDURES RESULTS AND DISCUSSION Cycling Method TABLE OF CONTENTS Page Vl , V111 lx 13 13 Effects of Control Temperature on the Cycling Method . Effects of kv/kh rat1o... Method and the Cycling Method in a 50 Ft Formation With kv/kh = I/3 Comparison of Net Rate Between the Mid-point Injection Method and the Cycling Method in a 50 Ft Formation With kv/kh = 1/3 31 32 34 35 36 25 26 Comparison of Production...

Oetama, Teddy

1983-01-01T23:59:59.000Z

378

A geological fingerprint of low-viscosity fault fluids mobilized during an earthquake  

E-Print Network [OSTI]

Deformation processes in unconsolidated sands, Geol. Soc.by the liquefaction of unconsolidated sands and some ancient

Brodsky, Emily E.; Rowe, Christie D.; Moore, J. Casey; Meneghini, Francesca

2009-01-01T23:59:59.000Z

379

Viscosity bound for anisotropic superfluids in higher derivative gravity  

E-Print Network [OSTI]

In the present paper, based on the principles of gauge/gravity duality we analytically compute the shear viscosity to entropy ratio corresponding to the superfluid phase in Einstein Gauss-Bonnet gravity. From our analysis we note that the ratio indeed receives a finite temperature correction below certain critical temperature. This proves the non universality of shear viscosity to entropy ratio in higher derivative theories of gravity. We also compute the upper bound for the Gauss-Bonnet coupling corresponding to the symmetry broken phase and note that the upper bound on the coupling does not seem to change as long as we are close to the critical point of the phase diagram. However the corresponding lower bound of the shear viscosity to entropy ratio seems to get modified due to the finite temperature effects.

Bhattacharyya, Arpan

2014-01-01T23:59:59.000Z

380

Viscosity bound for anisotropic superfluids in higher derivative gravity  

E-Print Network [OSTI]

In the present paper, based on the principles of gauge/gravity duality we analytically compute the shear viscosity to entropy ratio corresponding to the superfluid phase in Einstein Gauss-Bonnet gravity. From our analysis we note that the ratio indeed receives a finite temperature correction below certain critical temperature. This proves the non universality of shear viscosity to entropy ratio in higher derivative theories of gravity. We also compute the upper bound for the Gauss-Bonnet coupling corresponding to the symmetry broken phase and note that the upper bound on the coupling does not seem to change as long as we are close to the critical point of the phase diagram. However the corresponding lower bound of the shear viscosity to entropy ratio seems to get modified due to the finite temperature effects.

Arpan Bhattacharyya; Dibakar Roychowdhury

2014-10-13T23:59:59.000Z

Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Shear Viscosity in the Post-quasistatic Approximation  

E-Print Network [OSTI]

We apply the post-quasi--static approximation, an iterative method for the evolution of self-gravitating spheres of matter, to study the evolution of anisotropic non-adiabatic radiating and dissipative distributions in General Relativity. Dissipation is described by viscosity and free-streaming radiation, assuming an equation of state to model anisotropy induced by the shear viscosity. We match the interior solution, in non-comoving coordinates, with the Vaidya exterior solution. Two simple models are presented, based on the Schwarzschild and Tolman VI solutions, in the non--adiabatic and adiabatic limit. In both cases the eventual collapse or expansion of the distribution is mainly controlled by the anisotropy induced by the viscosity.

C. Peralta; L. Rosales; B. Rodrí guez-Mueller; W. Barreto

2010-03-09T23:59:59.000Z

382

Dissipative kinetic Alfvén solitary waves resulting from viscosity  

SciTech Connect (OSTI)

Nonlinear small-amplitude kinetic Alfvén solitary waves (KASWs) are investigated with their “anomalous” kinetic viscosity effect on electrons. It is found that the structure of a hump-type KASW solution develops into a shock-type (or double layer) KASW solution for large amplitude KASWs when viscosity exists. For small amplitude KASWs, the Korteweg-de Vries (KdV) equation with an approximate pseudopotential was solved, and it is found that the hump-type KASWs develop into oscillating shock-type (kink-type) KASWs. It is also found that the oscillating scale of this structure is related to the propagation velocity and plasma beta, while the damping scale is inversely proportional to the viscosity.

Choi, C.-R.; Kang, S.-B.; Min, K.-W. [Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of)] [Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of); Woo, M.-H. [National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of)] [National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Hwang, J.; Park, Y.-D. [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of)] [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of)

2013-11-15T23:59:59.000Z

383

A generalized viscosity equation for pure heavy hydrocarbons  

SciTech Connect (OSTI)

This paper presents a method for the correlation and prediction of the viscosity of pure heavy hydrocarbons listed in API Research Project 42. The 273 heavy hydrocarbons in the database include branched/unbranched paraffins and olefins together with a variety of complex nonfused/fused aromatic and naphthenic compounds. A generalized one-parameter viscosity-temperature equation, log ({mu} + 0.8) = 100(0.01T){sup b}, is proposed (overall AAD {lt} 7-10%) for all heavy hydrocarbons in the database. For each hydrocarbon, an optimum value of parameter b is provided. It is shown that parameter b varies linearly with the logarithm of molar mass as well as the inverse of boiling temperature (at 10 mmHg). This important observation leads to the development of a predictive method for the liquid-phase viscosity of pure heavy hydrocarbons.

Mehrotra, A.K. (Dept. of Chemical and Petroleum Engineering, Univ. of Calgary, Calgary, Alberta T2N 1N4 (CA))

1991-02-01T23:59:59.000Z

384

Polyacrylamide polymer viscosity as a function of brine composition  

SciTech Connect (OSTI)

A computer model has been developed which predicts the viscosity of polymer and oil field brine mixtures. The polymers used were Amoco- Sweepaid 103 and Dow- Pusher 500 polyacrylamide polymers. All of the experiments were conducted at 1200 ppM polymer concentration. The computer input consists of the ionic strength of the brine in the mixture and the fraction of that ionic strength due to sodium ions. The computer program makes predictions of viscosity by referencing a family of viscosity curves for various mixtures of sodium chloride and calcium chloride in 1200 ppM polymer solutions. The model has been tested using 59 mixtures of brines and polymers. The ionic strength of the brine in the mixtures varied from 0.0018 to 0.025. The fraction of the brines' total ionic strength due to sodium ions varied from 0.22 to 0.49. The brines consisted predominantly of sodium, potassium, magnesium, calcium, chloride, bicarbonate and sulfate ions.

French, T.R.; Stacy, N.; Collins, A.G.

1981-05-01T23:59:59.000Z

385

Memory Effects and Transport Coefficients for Non-Newtonian Fluids  

E-Print Network [OSTI]

We discuss the roles of viscosity in relativistic fluid dynamics from the point of view of memory effects. Depending on the type of quantity to which the memory effect is applied, different terms appear in higher order corrections. We show that when the memory effect applies on the extensive quantities, the hydrodynamic equations of motion become non-singular. We further discuss the question of memory effect in the derivation of transport coefficients from a microscopic theory. We generalize the application of the Green-Kubo-Nakano (GKN) to calculate transport coefficients in the framework of projection operator formalism, and derive the general formula when the fluid is non-Newtonian.

T. Kodama; T. Koide

2008-12-22T23:59:59.000Z

386

Nonlinear viscosity and its role in drift-Alfven modes  

SciTech Connect (OSTI)

The moment approach is used to analyze the part of the magnetized plasma viscosity related to the nonlinear character of the Landau collision integral in the Boltzmann kinetic equation (nonlinear viscosity), pointed out by Catto and Simakov [Phys. Plasmas 11, 90 (2004)]. It is shown that the results of these authors, who have used an alternative procedure based on a more detailed analysis of the kinetic equation, correspond to a 15-moment approach. In comparison with the 13-moment approach (density, temperature, velocity, heat flux, and the viscosity tensor) of Grad, the 15-moment approach takes into account two higher-order moments, one of which is the vector-type moment similar to the parallel heat flux and the second is the tensor-type moment similar to the parallel projection of the viscosity tensor. Both these higher-order moments enter into the Braginskii approximation. The nonlinear viscosity calculated in the scope of the 13-moment Grad approach is qualitatively the same as that found by Catto and Simakov. Its role is investigated for drift-Alfven modes, driven by the combined effect of the dissipative part of perpendicular heat conductivity and the standard collisional viscosity, and it is shown to be essential for the radial transport of these modes. It is shown that the wave packet of drift-Alfven modes, propagating in the diamagnetic drift direction and driven for reversed temperature gradient, is transported down the pressure gradient. In contrast to this, the wave packet propagating in the electron diamagnetic drift direction and driven for positive temperature gradient is transported up the pressure gradient.

Tsypin, V.S.; Mikhailovskii, A.B.; Shirokov, M.S.; Kovalishen, E.A.; Konovalov, S.V.; Galvao, R.M.O. [Physics Institute, University of Sao Paulo, Cidade Universitaria, 05508-900, Sao Paulo (Brazil); Institute of Nuclear Fusion, Russian Research Centre Kurchatov Institute, Kurchatov Sq., 1, Moscow 123182 (Russian Federation) and Nonlinear Physics Laboratory, Moscow Institute of Physics and Technology, Institutskii per. 9, Dolgoprudnyi 141700, Moscow Region (Russian Federation); Institute of Nuclear Fusion, Russian Research Centre Kurchatov Institute, Kurchatov Sq., 1, Moscow 123182 (Russian Federation) and Moscow Engineering Physics Institute, Kashirskoe Shosse 31, Moscow 115409 (Russian Federation); Nonlinear Physics Laboratory, Moscow Institute of Physics and Technology, Institutskii per. 9, Dolgoprudnyi 141700 (Russian Federation) and Institute of Nuclear Fusion, Russian Research Centre Kurchatov Institute, Kurchatov Sq., 1, Moscow 123182 (Russian Federation); Institute of Nuclear Fusion, Russian Research Centre Kurchatov Institute, Kurchatov Sq., 1, Moscow 123182 (Russian Federation); Physics Institute, University of Sao Paulo, Cidade Universitaria, 05508-900, Sao Paulo (Brazil) and Brazilian Center for Research in Physics, Rua Xavier Sigaud, 150, 22290-180, Rio de Janeiro (Brazil)

2005-12-15T23:59:59.000Z

387

Bulk viscosity of strongly coupled plasmas with holographic duals  

E-Print Network [OSTI]

We explain a method for computing the bulk viscosity of strongly coupled thermal plasmas dual to supergravity backgrounds supported by one scalar field. Whereas earlier investigations required the computation of the leading dissipative term in the dispersion relation for sound waves, our method requires only the leading frequency dependence of an appropriate Green's function in the low-frequency limit. With a scalar potential chosen to mimic the equation of state of QCD, we observe a slight violation of the lower bound on the ratio of the bulk and shear viscosities conjectured in arXiv:0708.3459.

Steven S. Gubser; Silviu S. Pufu; Fabio D. Rocha

2008-06-02T23:59:59.000Z

388

Bulk viscosity of the gluon plasma in a holographic approach  

E-Print Network [OSTI]

A gravity-scalar model in 5-dim. Riemann space is adjusted to the thermodynamics of SU(3) gauge field theory in the temperature range 1 - 10 $T/T_c$ to calculate holographically the bulk viscosity in 4-dim. Minkowski space. Various settings are compared, and it is argued that, upon an adjustment of the scalar potential to reproduce exactly the lattice data within a restricted temperature interval above $T_c$, rather robust values of the bulk viscosity to entropy density ratio are obtained.

R. Yaresko; B. Kampfer

2014-03-14T23:59:59.000Z

389

Fluid Inclusion Gas Analysis  

SciTech Connect (OSTI)

Fluid inclusion gas analysis for wells in various geothermal areas. Analyses used in developing fluid inclusion stratigraphy for wells and defining fluids across the geothermal fields. Each sample has mass spectrum counts for 180 chemical species.

Dilley, Lorie

2013-01-01T23:59:59.000Z

390

Experimental study of fluid flow and heat transfer in tortuous microchannels.  

E-Print Network [OSTI]

??Tortuous microchannels have attracted increasing interest due to great potential to enhance fluid mixing and heat transfer. While the fluid flow and heat transfer in… (more)

Dai, Zhenhui

2014-01-01T23:59:59.000Z

391

Shear Viscosity to Entropy within a Parton Cascade  

E-Print Network [OSTI]

The shear viscosity is calculated by means of the perturbative kinetic partonic cascade BAMPS with CGC initial conditons for various saturation momentum scale Q_s. eta/s ~ 0.15 stays approximately constant when going from RHIC to LHC.

A. El; C. Greiner; Z. Xu

2007-06-28T23:59:59.000Z

392

Universal viscosity to entropy density ratio from entanglement  

SciTech Connect (OSTI)

We present evidence that the universal Kovtun-Son-Starinets shear viscosity to entropy density ratio of 1/4{pi} can be associated with a Rindler causal horizon in flat spacetime. Since there is no known holographic (gauge/gravity) duality for this spacetime, a natural microscopic explanation for this viscosity is in the peculiar properties of quantum entanglement. In particular, it is well known that the Minkowski vacuum state is a thermal state and carries an area entanglement entropy density in the Rindler spacetime. Based on the fluctuation-dissipation theorem, we expect a similar notion of viscosity arising from vacuum fluctuations. Therefore, we propose a holographic Kubo formula in terms of a two-point function of the stress tensor of matter fields in the bulk. We calculate this viscosity assuming a minimally coupled scalar field theory and find that the ratio with respect to the entanglement entropy density is exactly 1/4{pi} in four dimensions. The issues that arise in extending this result to nonminimally coupled scalar fields, higher spins, and higher dimensions provide interesting hints about the relationship between entanglement entropy and black hole entropy.

Chirco, Goffredo; Eling, Christopher; Liberati, Stefano [SISSA, Via Bonomea 265, 34136 Trieste (Italy) and INFN Sezione di Trieste, Via Valerio 2, 34127 Trieste (Italy)

2010-07-15T23:59:59.000Z

393

Viscosity from elliptic flow: the path to precision  

E-Print Network [OSTI]

Using viscous relativistic hydrodynamics we show that systematic studies of the impact parameter dependence of the eccentricity scaled elliptic flow can distinguish between different models for the calculation of the initial source eccentricity. This removes the largest present uncertainty in the extraction of the specific viscosity of the matter created in relativistic heavy-ion collisions from precise elliptic flow measurements.

Ulrich W. Heinz; J. Scott Moreland; Huichao Song

2009-08-18T23:59:59.000Z

394

Shear viscosity of boost invariant plasma at finite coupling  

E-Print Network [OSTI]

We discuss string theory alpha' corrections in the dual description of the expanding boost invariant N=4 supersymmetric Yang-Mills plasma at strong coupling. We compute finite 't Hooft coupling corrections to the shear viscosity and find that it disagrees with the equilibrium correlation function computations. We comment on the possible source of the discrepancy.

Alex Buchel

2008-01-29T23:59:59.000Z

395

Experimental investigations and theoretical determination of thermal conductivity and viscosity of Al{sub 2}O{sub 3}/water nanofluid  

SciTech Connect (OSTI)

Experimental investigations and theoretical determination of effective thermal conductivity and viscosity of Al{sub 2}O{sub 3}/H{sub 2}O nanofluid are reported in this paper. The nanofluid was prepared by synthesizing Al{sub 2}O{sub 3} nanoparticles using microwave assisted chemical precipitation method, and then dispersing them in distilled water using a sonicator. Al{sub 2}O{sub 3}/water nanofluid with a nominal diameter of 43 nm at different volume concentrations (0.33-5%) at room temperature were used for the investigation. The thermal conductivity and viscosity of nanofluids are measured and it is found that the viscosity increase is substantially higher than the increase in thermal conductivity. Both the thermal conductivity and viscosity of nanofluids increase with the nanoparticle volume concentration. Theoretical models are developed to predict thermal conductivity and viscosity of nanofluids without resorting to the well established Maxwell and Einstein models, respectively. The proposed models show reasonably good agreement with our experimental results. (author)

Chandrasekar, M.; Suresh, S. [Department of Mechanical Engineering, National Institute of Technology, Tiruchirappalli 620 015 (India); Chandra Bose, A. [Nanomaterials Laboratory, National Institute of Technology, Tiruchirappalli 620 015 (India)

2010-02-15T23:59:59.000Z

396

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

Science Journals Connector (OSTI)

Measurements of thermophysical properties (vapour pressure, density, and viscosity) of the (water + lithium bromide + potassium acetate) system LiBr:CH3COOK = 2:1 by mass ratio and the (water + lithium bromide + sodium lactate) system LiBr:CH3CH(OH)COONa = 2:1 by mass ratio were measured. The system, a possible new working fluid for absorption heat pump, consists of absorbent (LiBr + CH3COOK) or (LiBr + CH3CH(OH)COONa) and refrigerant H2O. 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.

Antonio de Lucas; Marina Donate; Juan F. Rodríguez

2006-01-01T23:59:59.000Z

397

Effect of viscosity on the plasma decay in a magnetic field  

SciTech Connect (OSTI)

The effect of viscosity on the evolution of an axisymmetric plasma column in a longitudinal magnetic field is considered. It is found that, under the action of viscosity, the plasma density profile tends to become Gaussian.

Timofeev, A. V.; Kuyanov, A. Yu. [Russian Research Centre Kurchatov Institute (Russian Federation)

2010-11-15T23:59:59.000Z

398

Synthesis and evaluation of an oil-soluble viscosity reducer for heavy oil  

Science Journals Connector (OSTI)

To reduce the viscosity of highly-viscous oil of the Tahe oilfield (Xinjiang, China), an oilsoluble polybasic copolymer viscosity reducer for heavy oil was synthesized using the orthogonal method. The optimum ...

Jixiang Guo; Heyi Wang; Chaogang Chen; Yun Chen; Xiaohai Xie

2010-12-01T23:59:59.000Z

399

Fluid transport container  

DOE Patents [OSTI]

An improved fluid container for the transport, collection, and dispensing of a sample fluid that maintains the fluid integrity relative to the conditions of the location at which it is taken. More specifically, the invention is a fluid sample transport container that utilizes a fitting for both penetrating and sealing a storage container under controlled conditions. Additionally, the invention allows for the periodic withdrawal of portions of the sample fluid without contamination or intermixing from the environment surrounding the sample container. 13 figs.

DeRoos, B.G.; Downing, J.P. Jr.; Neal, M.P.

1995-11-14T23:59:59.000Z

400

Bulk viscosity of superfluid hyperon stars Mikhail E. Gusakov and Elena M. Kantor  

E-Print Network [OSTI]

Bulk viscosity of superfluid hyperon stars Mikhail E. Gusakov and Elena M. Kantor Ioffe Physical; published 14 October 2008) We calculate the bulk viscosity due to nonequilibrium weak processes bulk viscosity coefficients, with only three of them being independent. In addition, we correct

Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

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

DOE Patents [OSTI]

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

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

1985-01-01T23:59:59.000Z

402

Viscosity and longest relaxation time of semi-dilute polymer solutions. I. Good solvent  

E-Print Network [OSTI]

1185 Viscosity and longest relaxation time of semi-dilute polymer solutions. I. Good solvent M expliqués par un modèle de reptation classique. Abstract. 2014 The zero shear viscosity and longest concentration (4 c/c* 70), we find that : 2014 both the relative viscosity ~r and the longest relaxation time TR

Paris-Sud XI, Université de

403

Viscosity and solute dependence of F-actin translocation by rabbit skeletal heavy meromyosin  

E-Print Network [OSTI]

Viscosity and solute dependence of F-actin translocation by rabbit skeletal heavy meromyosin P, Ying Chen, Kristi L. Kulin, and Thomas L. Daniel. Viscosity and solute dependence of F the hypothesis that solvent viscosity affects transloca- tion of rhodamine phalloidin-labeled F-actin by rabbit

Daniel, Tom

404

Viscosity of carbon nanotubes water based nanofluids: Influence of1 concentration and temperature2  

E-Print Network [OSTI]

1 Viscosity of carbon nanotubes water based nanofluids: Influence of1 concentration and temperature 0019 Fax: +33 (0) 2 23 23 40 5120 21 Abstract:22 23 Experimental results on the steady state viscosity, the nanofluids are quite Newtonian. It is also observed that the relative viscosity of30 nanofluids at high shear

Paris-Sud XI, Université de

405

Viscosity of magmas containing highly deformable bubbles M. Mangaa,*, M. Loewenbergb  

E-Print Network [OSTI]

Viscosity of magmas containing highly deformable bubbles M. Mangaa,*, M. Loewenbergb a Department The shear viscosity of a suspension of deformable bubbles dispersed within a Newtonian ¯uid is calculated. For small Ca, bubbles remain nearly spherical, and for suf®ciently large strains the viscosity of suspension

Manga, Michael

406

On viscosity solutions of certain Hamilton-Jacobi equations: Regularity results and generalized Sard's Theorems  

E-Print Network [OSTI]

On viscosity solutions of certain Hamilton-Jacobi equations: Regularity results and generalized prove that any viscosity solution of the corresponding Hamilton-Jacobi equation on the manifold M). Moreover, we prove that, under additional assumptions and in low dimension, any viscosity solution

Paris-Sud XI, Université de

407

Viscosity and elastic constants of amorphous Si and Ge Ann Witwow@ and Frans Spaepen  

E-Print Network [OSTI]

Viscosity and elastic constants of amorphous Si and Ge Ann Witwow@ and Frans Spaepen Division expansion. Viscous flow was measured by stress relaxation and was found to be Newtonian. The viscosity of the viscosity of sputter-deposited samples as a function of stress (to establish the Newtonian charac- ter

Spaepen, Frans A.

408

A Viscosity Approach to Total Variation Flows of Non-Divergence Type  

E-Print Network [OSTI]

A Viscosity Approach to Total Variation Flows of Non-Divergence Type Norbert Poz´ar Graduate School, we will introduce a notion of viscosity solutions for a class of singular nonlinear parabolic viscosity theory does not apply is the unboundedness of the operator on the right-hand side of (5) at u = 0

Ishii, Hitoshi

409

A low viscosity wedge in subduction zones Magali I. Billen *, Michael Gurnis  

E-Print Network [OSTI]

A low viscosity wedge in subduction zones Magali I. Billen *, Michael Gurnis Seismological mantle wedge), which could decrease the viscosity of the mantle locally by several orders of magnitude. Using numerical models we demonstrate that a low viscosity wedge has a dramatic influence on the force

Billen, Magali I.

410

The viscosity structure of the D00 layer of the Earth's mantle inferred  

E-Print Network [OSTI]

The viscosity structure of the D00 layer of the Earth's mantle inferred from the analysis layer Core�mantle boundary Viscosity Maxwell body a b s t r a c t The viscosity structure of the D00-diurnal to 18.6 years tidal deformations combined with model viscosity�depth profiles corresponding to a range

411

Viscosity and dilepton production of a chemically equilibrating quark-gluon plasma at finite baryon density  

E-Print Network [OSTI]

By considering the effect of shear viscosity we have investigated the evolution of a chemically equilibrating quark-gluon plasma at finite baryon density. Based on the evolution of the system we have performed a complete calculation for the dilepton production from the following processes: $q\\bar{q}{\\to}l\\bar{l}$, $q\\bar{q}{\\to}gl\\bar{l}$, Compton-like scattering ($qg{\\to}ql\\bar{l}$, $\\bar{q}g{\\to}{\\bar{q}}l\\bar{l}$), gluon fusion $g\\bar{g}{\\to}c\\bar{c}$, annihilation $q\\bar{q}{\\to}c\\bar{c}$ as well as the multiple scattering of quarks. We have found that quark-antiquark annihilation, Compton-like scatterring, gluon fusion, and multiple scattering of quarks give important contributions. Moreover, we have also found that the dilepton yield is an increasing function of the initial quark chemical potential, and the increase of the quark phase lifetime because of the viscosity also obviously raises the dilepton yield.

N. N. Guan; Z. J. He; J. L. Long; X. Z. Cai; Y. G. Ma; J. W. Li; W. Q. Shen

2009-09-02T23:59:59.000Z

412

Apparatus and method for high temperature viscosity and temperature measurements  

DOE Patents [OSTI]

A probe for measuring the viscosity and/or temperature of high temperature liquids, such as molten metals, glass and similar materials comprises a rod which is an acoustical waveguide through which a transducer emits an ultrasonic signal through one end of the probe, and which is reflected from (a) a notch or slit or an interface between two materials of the probe and (b) from the other end of the probe which is in contact with the hot liquid or hot melt, and is detected by the same transducer at the signal emission end. To avoid the harmful effects of introducing a thermally conductive heat sink into the melt, the probe is made of relatively thermally insulative (non-heat-conductive) refractory material. The time between signal emission and reflection, and the amplitude of reflections, are compared against calibration curves to obtain temperature and viscosity values.

Balasubramaniam, Krishnan (Mississippi State, MS); Shah, Vimal (Houston, TX); Costley, R. Daniel (Mississippi State, MS); Singh, Jagdish P. (Mississippi State, MS)

2001-01-01T23:59:59.000Z

413

Kinetic Alfven double layer formed by electron viscosity  

SciTech Connect (OSTI)

The effect of the electron viscosity on the kinetic Alfven solitary wave is investigated. It is found that small electron viscosity changes the electron motion along the magnetic field producing a boundary layer, and thus that in a low beta electron-ion plasma({beta} Much-Less-Than m{sub e}/m{sub i}), an obliquely propagating kinetic solitary Alfven wave can become a double layer. This double layer can exist in the sub-Alfvenic and super-Alfvenic regimes. The length scale of density drop for this double layer is on the order of that of the conventional kinetic solitary Alfven wave, and thus this double layer can accelerate electrons on a very short length scale.

Woo, M. H.; Ryu, C.-M. [Department of Physics, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Choi, C. R. [Department of Physics, Korea Advanced Institute of Science and Technology, Taejon 305-701 (Korea, Republic of)

2012-07-15T23:59:59.000Z

414

Viscosity and the phenomenon of percolation in microemulsions  

Science Journals Connector (OSTI)

The viscosity of water/AOT/oil microemulsions (undecane, isooctane, cyclohexane) has been studied as a function of the molar ratio n=[water]/[AOT] and the volume fraction ? (water + AOT) at T=25 °C. [Here AOT is an abbreviation for sodium bis(2-ethylhexyl)sulfosuccinate.] At constant ? and variable n, the presence of a maximum viscosity can be observed. The results are discussed in connection with a percolation model and a very good qualitative agreement is obtained. The results are compatible with those obtained previously on the conductivity and complex permittivity of these microemulsions. The results show the importance of the idea of ‘‘percolation threshold lines.’’ Emphasis is placed on the importance of interactions and on the necessity of following an experimental procedure involving constant interaction (for either ternary or quaternary systems).

J. Peyrelasse; M. Moha-Ouchane; C. Boned

1988-10-15T23:59:59.000Z

415

Mantle viscosity and ice-age ice sheet topography  

SciTech Connect (OSTI)

Ice-age paleotopography and mantle viscosity can both be inferred from observations of Earth`s response to the most recent deglaciation event of the current ice age. This procedure requires iterative application of a theoretical model of the global process of glacial isostatic adjustment. Results demonstrate that the iterative inversion procedure converges to a paleotopography that is extremely close to that from the ICE-4G model. The accompanying mantle viscosity profile is furthermore shown to reconcile the requirements of aspherical geoid anomalies related to the mantle convection process, thus resolving a fundamental issue concerning mantle rheology. The combined model also explains postglacial sea level histories for the east cost of the United States. 28 refs., 9 figs.

Peltier, W.R. [Univ. of Toronto, Ontario (Canada)

1996-09-06T23:59:59.000Z

416

Magnetic component of gluon plasma and its viscosity  

E-Print Network [OSTI]

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

M. N. Chernodub; H. Verschelde; V. I. Zakharov

2009-05-15T23:59:59.000Z

417

Shear viscosity and chemical equilibration of the QGP  

E-Print Network [OSTI]

We have investigated, in the frame work of the transport approach, different aspects of the QGP created in Heavy Ion Collisions at RHIC and LHC energies. The shear viscosity $\\eta$ has been calculated by using the Green-Kubo relation at the cascade level. We have compared the numerical results for $\\eta$ obtained from the Green-Kubo correlator with the analytical formula in both the Relaxation Time Approximation (RTA) and the Chapman-Enskog approximation (CE). From this comparison we show that in the range of temperature explored in a Heavy Ion collision the RTA underestimates the viscosity by about a factor of 2, while a good agreement is found between the CE approximation and Gree-Kubo relation already at first order of approximation. The agreement with the CE approximation supplies an analytical formula that allows to develop kinetic transport theory at fixed shear viscosity to entropy density ratio, $\\eta/s$. We show some results for the build up of anisotropic flows $v_{2}$ in a transport approach at fixed shear viscosity to entropy density ratio, $\\eta/s$. We study the impact of a T-dependent $\\eta/s(T)$ on the generation of the elliptic flows at both RHIC and LHC. We show that the transport approach provides, in a unified way, a tool able to naturally describe the $v_{2}(p_{T})$ in a wide range of $p_{T}$, including also the description of the rise and fall and saturation of the $v_{2}(p_{T})$ observed at LHC. Finally, we have studied the evolution of the quark-gluon composition employing a Boltzmann-Vlasov transport approach that include: the mean fields dynamics, associated to the quasi-particle model, and the elastic and inelastic collisions for massive quarks and gluons. Following the chemical evolution from an initial gluon dominated plasma we predict a quark dominance close to $T_{C}$ paving the way to an hadronization via quark coalescence.

Salvatore Plumari; Armando Puglisi; Maria Colonna; Francesco Scardina; Vincenzo Greco

2012-09-04T23:59:59.000Z

418

Viscosity and Diffusion: Crowding and Salt Effects in Protein Solutions  

E-Print Network [OSTI]

We report on a joint experimental-theoretical study of collective diffusion in, and static shear viscosity of solutions of bovine serum albumin (BSA) proteins, focusing on the dependence on protein and salt concentration. Data obtained from dynamic light scattering and rheometric measurements are compared to theoretical calculations based on an analytically treatable spheroid model of BSA with isotropic screened Coulomb plus hard-sphere interactions. The only input to the dynamics calculations is the static structure factor obtained from a consistent theoretical fit to a concentration series of small-angle X-ray scattering (SAXS) data. This fit is based on an integral equation scheme that combines high accuracy with low computational cost. All experimentally probed dynamic and static properties are reproduced theoretically with an at least semi-quantitative accuracy. For lower protein concentration and low salinity, both theory and experiment show a maximum in the reduced viscosity, caused by the electrostatic repulsion of proteins. The validity range of a generalized Stokes-Einstein (GSE) relation connecting viscosity, collective diffusion coefficient, and osmotic compressibility, proposed by Kholodenko and Douglas [PRE 51, 1081 (1995)] is examined. Significant violation of the GSE relation is found, both in experimental data and in theoretical models, in semi-dilute systems at physiological salinity, and under low-salt conditions for arbitrary protein concentrations.

Marco Heinen; Fabio Zanini; Felix Roosen-Runge; Diana Fedunová; Fajun Zhang; Marcus Hennig; Tilo Seydel; Ralf Schweins; Michael Sztucki; Marián Antalík; Frank Schreiber; Gerhard Nägele

2011-09-14T23:59:59.000Z

419

Quantum Bound of the Shear Viscosity of a Strongly Coupled Plasma  

Science Journals Connector (OSTI)

String theory methods led to the hypothesis that the ratio of a shear viscosity coefficient to the volume density of entropy of any physical system has a lower bound. Systems with strong coupling have a small viscosity as compared to weakly coupled plasmas in which the viscosity is proportional to the mean free path. Here, we have estimated the fully ionized strongly coupled plasma viscosity based on the dynamic experimental data on electrical conductivity and have shown that the ratio of viscosity to entropy of the strongly coupled plasma is very close to that of the lower bound predicted by the string theory.

V. E. Fortov and V. B. Mintsev

2013-09-17T23:59:59.000Z

420

Viscosity Determination of Molten Ash from Low-Grade US Coals  

SciTech Connect (OSTI)

In entrained slagging gasifiers, the fluidity of the molten ash is a critical factor for process control since it affects slag formation, the capture of inorganic constituents, refractory wear, and slag drainage along the gasification chamber walls. The use of western coal, or mixtures of eastern and western coals as gasifier feedstock, is likely to occur as western coals become available and technological issues that hinder their use are being resolved. In the present work, the viscosity of synthetic slags with ash chemistries simulating the western U.S. coals, was experimentally measured at a Po2?=?10- 8 atm in the temperature range of 1773–1573 K (1500–1300 °C) using a rotating-bob viscometer. Alumina spindles and containment crucibles of both alumina and zirconia were used. Crystallization studies of this slag using a confocal scanning laser microscope found that a (Mg,Fe)Al2O4-based spinel precipitated at temperatures below 1723 K (1450 °C), and this agreed with FactSage equilibrium phase prediction. The same spinels were observed in the post-viscometry experiment slags when ZrO2 crucibles were used and assumed to be in equilibrium with the slag at the higher temperatures. Zirconia dissolution resulted in a slight increase in the solid fraction present in slags at lower temperatures, compared to spinel fraction. Crystal precipitation changed the apparent activation energy and required a longer stabilization times for viscosity measurements. The viscosity results were used in predictive equations based on Veytsman and Einstein's models, with critical nucleation temperatures and the solid fraction calculated with FactSage. In the simulated eastern/western coal feedstock blends based on ash compositions, the fractions of the solid precipitates were also calculated using the thermodynamic program FactSage for each blend composition, and the plastic viscosity of each eastern/western coal slag blend was predicted using Veytsman's model and compared to available experimental data.

Zhu, Jingxi [National Energy Technology Laboratory (NETL), Pittsburgh, PA, and Morgantown, WV (United States); URS Corp., Albany, OR (United States); Nakano, Jinichiro [National Energy Technology Laboratory (NETL), Pittsburgh, PA, and Morgantown, WV (United States); URS Corp., Albany, OR (United States); Kaneko, Tetsuya Kenneth [National Energy Technology Laboratory (NETL), Pittsburgh, PA, and Morgantown, WV (United States); Carnegie Mellon Univ., Pittsburgh, PA (United States); Mu, Haoyuan [Carnegie Mellon Univ., Pittsburgh, PA (United States); Bennett, James P. [National Energy Technology Laboratory (NETL), Pittsburgh, PA, and Morgantown, WV (United States); Kwong, Kyei-Sing [National Energy Technology Laboratory (NETL), Pittsburgh, PA, and Morgantown, WV (United States); Rozelle, Peter [US Dept. of Energy, Washington, DC (United States). Office of Clean Energy Systems; Sridhar, Seetharaman [National Energy Technology Laboratory (NETL), Pittsburgh, PA, and Morgantown, WV (United States); Carnegie Mellon Univ., Pittsburgh, PA (United States)

2011-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Standardization of Thermo-Fluid Modeling in Modelica.Fluid  

E-Print Network [OSTI]

Thermo-Fluid Systems, Modelica 2003 Conference, Linköping,H. Tummescheit: The Modelica Fluid and Media Library forThermo-Fluid Pipe Networks, Modelica 2006 Conference, Vi-

Franke, Rudiger

2010-01-01T23:59:59.000Z

422

Shear-Viscosity to Entropy Density Ratio of a Relativistic Hadron Gas  

E-Print Network [OSTI]

Ultrarelativistic heavy-ion collisions at the Relativistic Heavy-Ion Collider (RHIC) are thought to have produced a state of matter called the Quark-Gluon-Plasma, characterized by a very small shear viscosity to entropy density ratio $\\eta/s$, near the lower bound predicted for that quantity by Anti-deSitter space/Conformal Field Theory (AdS/CFT) methods. As the produced matter expands and cools, it evolves through a phase described by a hadron gas with rapidly increasing $\\eta/s$. We calculate $\\eta/s$ as a function of temperature in this phase and find that its value poses a challenge for viscous relativistic hydrodynamics, which requires small values of $\\eta/s$ throughout the entire evolution of the reaction in order to successfully describe the collective flow observables at RHIC. We show that the inclusion of non-unit fugacities will reduce $\\eta/s$ in the hadronic phase, yet not sufficiently to be compatible with viscous hydrodynamics. We therefore conclude that the origin of the low viscosity matter at RHIC must be in the partonic phase of the reaction.

Nasser Demir; Steffen A. Bass

2008-12-12T23:59:59.000Z

423

Working Fluids Low Global Warming Potential Refrigerants  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Working Fluids Low GWP Working Fluids Low GWP Refrigerants - CRADA Ed Vineyard Oak Ridge National Laboratory vineyardea@ornl.gov (865) 574-0576 3 April 2013 2 | Building Technologies Office eere.energy.gov Purpose & Objectives Problem Statement: - High GWP refrigerants increase CO 2 equivalent emissions for HVAC&R equipment - Low GWP alternatives may increase energy consumption, introduce safety risks, require significant modifications to equipment, and have higher costs

424

Working Fluids Low Global Warming Potential Refrigerants  

Broader source: Energy.gov (indexed) [DOE]

Working Fluids Low GWP Working Fluids Low GWP Refrigerants - CRADA Ed Vineyard Oak Ridge National Laboratory vineyardea@ornl.gov (865) 574-0576 3 April 2013 2 | Building Technologies Office eere.energy.gov Purpose & Objectives Problem Statement: - High GWP refrigerants increase CO 2 equivalent emissions for HVAC&R equipment - Low GWP alternatives may increase energy consumption, introduce safety risks, require significant modifications to equipment, and have higher costs

425

Friction-Induced Fluid Heating in Nanoscale Helium Flows  

SciTech Connect (OSTI)

We investigate the mechanism of friction-induced fluid heating in nanoconfinements. Molecular dynamics simulations are used to study the temperature variations of liquid helium in nanoscale Poiseuille flows. It is found that the fluid heating is dominated by different sources of friction as the external driving force is changed. For small external force, the fluid heating is mainly caused by the internal viscous friction in the fluid. When the external force is large and causes fluid slip at the surfaces of channel walls, the friction at the fluid-solid interface dominates over the internal friction in the fluid and is the major contribution to fluid heating. An asymmetric temperature gradient in the fluid is developed in the case of nonidentical walls and the general temperature gradient may change sign as the dominant heating factor changes from internal to interfacial friction with increasing external force.

Li Zhigang [Department of Mechanical Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)

2010-05-21T23:59:59.000Z

426

Environmentally safe fluid extractor  

DOE Patents [OSTI]

An environmentally safe fluid extraction device for use in mobile laboratory and industrial settings comprising a pump, compressor, valving system, waste recovery tank, fluid tank, and a exhaust filtering system.

Sungaila, Zenon F. (Orland Park, IL)

1993-01-01T23:59:59.000Z

427

HEAT TRANSFER FLUIDS  

E-Print Network [OSTI]

The choice of heat transfer fluids has significant effects on the performance, cost, and reliability of solar thermal systems. In this chapter, we evaluate existing heat transfer fluids such as oils and molten salts based ...

Lenert, Andrej

2012-01-01T23:59:59.000Z

428

Fluid force transducer  

DOE Patents [OSTI]

An electrical fluid force transducer for measuring the magnitude and direction of fluid forces caused by lateral fluid flow, includes a movable sleeve which is deflectable in response to the movement of fluid, and a rod fixed to the sleeve to translate forces applied to the sleeve to strain gauges attached to the rod, the strain gauges being connected in a bridge circuit arrangement enabling generation of a signal output indicative of the magnitude and direction of the force applied to the sleeve.

Jendrzejczyk, Joseph A. (Warrenville, IL)

1982-01-01T23:59:59.000Z

429

The viscosity of quark-gluon plasma at RHIC and the LHC  

E-Print Network [OSTI]

The specific shear viscosity (eta/s)_QGP of quark-gluon plasma (QGP) can be extracted from elliptic flow data in heavy-ion collisions by comparing them with the dynamical model VISHNU which couples a viscous fluid dynamic description of the QGP with a microscopic kinetic description of the late hadronic rescattering and freeze-out stage. A robust method for fixing (eta/s)_QGP from the collision centrality dependence of the eccentricity-scaled charged hadron elliptic flow is presented. The systematic uncertainties associated with this extraction method are discussed, with specific attention to our presently restricted knowledge of initial conditions. With the (eta/s)_QGP extracted in this way, VISHNU yields an excellent description of all soft-hadron data from Au+Au collisions at top RHIC energy. Extrapolations to Pb+Pb collisions at the LHC, using both a purely hydrodynamic approach and VISHNU, are presented and compared with recent experimental results from the ALICE Collaboration. The LHC data are again well described by VISHNU, with the same (eta/s)_QGP value as at RHIC energies.

Ulrich W. Heinz; Chun Shen; Huichao Song

2011-08-26T23:59:59.000Z

430

Self-similar analytic solution of the two dimensional Navier-Stokes equation with a non-Newtonian type of viscosity  

E-Print Network [OSTI]

We investigate the two dimensional incompressible Navier-Stokes(NS) and the continuity equations in Cartesian coordinates and Eulerian description for non-Newtonian fluids. As a non-Newtonian viscosity we consider the Ladyzenskaya model with a non-linear velocity dependent stress tensor. The key idea is the multi-dimensional generalization of the well-known self-similar Ansatz, which was already used for non-compressible and compressible viscous flow studies. The geometrical interpretations of the trial function is also discussed. We compare our recent results to the former Newtonian ones.

Barna, Imre Ferenc

2014-01-01T23:59:59.000Z

431

Measurement of surface tension and viscosity by open capillary techniques  

DOE Patents [OSTI]

An open-channel capillary is provided, having preferably a v-shaped groove in a flat wettable surface. The groove has timing marks and a source marker in which the specimen to be tested is deposited. The time of passage between the timing marks is recorded, and the ratio of surface tension .gamma. to viscosity .mu. is determined from the equation given below: ##EQU1## where h.sub.0 is the groove depth, .alpha. is the groove angle, .theta. is the liquid/solid contact angle, and t is the flow time. It has been shown by the

Rye,Robert R. (Albuquerque, NM), Yost,Frederick G. (Cedar Crest, NM)

1998-01-01T23:59:59.000Z

432

Motion of Fluids in the Presence of a Boundary | ornl.gov  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Motion of Fluids in the Presence of a Boundary Motion of Fluids in the Presence of a Boundary Jan 09 2014 10:00 AM - 11:00 AM Gung-Min Gie, Indiana University, Bloomington Computer Science and Mathematics Division Seminar Joint Institute for Computational Sciences (Building 5100), Auditorium (Room 128) CONTACT : Email: Clayton Webster Phone:865.574.3649 Add to Calendar SHARE In most practical applications of fluid mechanics, it is the interaction of the fluid with the boundary that is most critical to understanding the behavior of the fluid. Physically important parameters, such as the lift and drag of a wing, are determined by the sharp transition the air makes from being at rest on the wing to flowing freely around the airplane near the wing. Mathematically, the behavior of such flows at small viscosity is

433

Heat Transfer Fluids for Solar Water Heating Systems | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

Heat Transfer Fluids for Solar Water Heating Systems Heat Transfer Fluids for Solar Water Heating Systems Heat Transfer Fluids for Solar Water Heating Systems May 16, 2013 - 3:02pm Addthis Illustration of a solar water heater. Illustration of a solar water heater. Heat-transfer fluids carry heat through solar collectors and a heat exchanger to the heat storage tanks in solar water heating systems. When selecting a heat-transfer fluid, you and your solar heating contractor should consider the following criteria: Coefficient of expansion - the fractional change in length (or sometimes in volume, when specified) of a material for a unit change in temperature Viscosity - resistance of a liquid to sheer forces (and hence to flow) Thermal capacity - the ability of matter to store heat Freezing point - the temperature below which a liquid turns into a

434

Fluid breakup during simultaneous two-phase flow through a three-dimensional porous medium  

E-Print Network [OSTI]

We use confocal microscopy to directly visualize the simultaneous flow of both a wetting and a non-wetting fluid through a model three-dimensional (3D) porous medium. We find that, for small flow rates, both fluids flow through unchanging, distinct, connected 3D pathways; in stark contrast, at sufficiently large flow rates, the non-wetting fluid is broken up into discrete ganglia. By performing experiments over a range of flow rates, using fluids of different viscosities, and with porous media having different geometries, we show that this transition can be characterized by a state diagram that depends on the capillary numbers of both fluids, suggesting that it is controlled by the competition between the viscous forces exerted on the flowing oil and the capillary forces at the pore scale. Our results thus help elucidate the diverse range of behaviors that arise in two-phase flow through a 3D porous medium.

Sujit S. Datta; Jean-Baptiste Dupin; David A. Weitz

2014-06-26T23:59:59.000Z

435

Bulk viscosity and cavitation in boost-invariant hydrodynamic expansion  

E-Print Network [OSTI]

We solve second order relativistic hydrodynamics equations for a boost-invariant 1+1-dimensional expanding fluid with an equation of state taken from lattice calculations of the thermodynamics of strongly coupled quark-gluon ...

Rajagopal, Krishna

436

Definition: Isotopic Analysis- Fluid | Open Energy Information  

Open Energy Info (EERE)

Definition Definition Edit with form History Facebook icon Twitter icon » Definition: Isotopic Analysis- Fluid Jump to: navigation, search Dictionary.png Isotopic Analysis- Fluid Isotopes are atoms of the same element that have different numbers of neutrons. An isotopic analysis looks at a particular isotopic element(s) in a given system, while the conditions which increase/decrease the number of neutrons are well understood and measurable. Fluid isotopes are used to characterize a fluids origin, age, and/or interaction with rocks or other fluids based on unique isotopic ratios or concentrations.[1] View on Wikipedia Wikipedia Definition Isotope geochemistry is an aspect of geology based upon study of the relative and absolute concentrations of the elements and their isotopes in

437

Notes 06. Liquid cavitation in fluid film bearings  

E-Print Network [OSTI]

[s] U ?R. Journal surface speed [m/s] V dh/dt. Squeeze film velocity [m/s] X= ?R, y, z Coordinate system on plane of bearing ? ()/ cav ?? . Density ratio ? P ? ? ? ? . Liquid bulk-modulus [N/m 2 ] ? Liquid density [kg/m 3 ] cav... ? Density at Pcav [kg/m 3 ] ? Fluid absolute viscosity [N.s/m 2 ] ? Journal angular speed (rad/s) Subscripts * Inception of the cavitation zone a Ambient value cav Cavitation NOTES 6. CAVITATION IN LIQUID FILM BEARINGS. Dr. Luis San Andr?s ? 2009...

San Andres, Luis

2009-01-01T23:59:59.000Z

438

Shear Viscosity to Entropy Density Ratio in Six Derivative Gravity  

E-Print Network [OSTI]

We calculate shear viscosity to entropy density ratio in presence of four derivative (with coefficient $\\alpha'$) and six derivative (with coefficient $\\alpha'^2$) terms in bulk action. In general, there can be three possible four derivative terms and ten possible six derivative terms in the Lagrangian. Among them two four derivative and eight six derivative terms are ambiguous, i.e., these terms can be removed from the action by suitable field redefinitions. Rest are unambiguous. According to the AdS/CFT correspondence all the unambiguous coefficients (coefficients of unambiguous terms) can be fixed in terms of field theory parameters. Therefore, any measurable quantities of boundary theory, for example shear viscosity to entropy density ratio, when calculated holographically can be expressed in terms of unambiguous coefficients in the bulk theory (or equivalently in terms of boundary parameters). We calculate $\\eta/s$ for generic six derivative gravity and find that apparently it depends on few ambiguous coefficients at order $\\alpha'^2$. We calculate six derivative corrections to central charges $a$ and $c$ and express $\\eta/s$ in terms of these central charges and unambiguous coefficients in the bulk theory.

Nabamita Banerjee; Suvankar Dutta

2009-03-23T23:59:59.000Z

439

Bulk viscosity of strange matter and r-modes in neutron stars  

E-Print Network [OSTI]

We discuss bulk viscosity due to non-leptonic processes involving hyperons and Bose-Einstein condensate of negatively charged kaons in neutron stars. It is noted that the hyperon bulk viscosity coefficient is a few order of magnitude larger than that of the case with the condensate. Further it is found that the hyperon bulk viscosity is suppressed in a superconducting phase. The hyperon bulk viscosity efficiently damps the r-mode instability in neutron stars irrespective of whether a superconducting phase is present or not in neutron star interior.

Debarati Chatterjee; Debades Bandyopadhyay

2008-12-30T23:59:59.000Z

440

Viscosity calculated in simulations of strongly coupled dusty plasmas with gas friction  

SciTech Connect (OSTI)

A two-dimensional strongly coupled dusty plasma is modeled using Langevin and frictionless molecular dynamical simulations. The static viscosity {eta} and the wave-number-dependent viscosity {eta}(k) are calculated from the microscopic shear in the random motion of particles. A recently developed method of calculating the wave-number-dependent viscosity {eta}(k) is validated by comparing the results of {eta}(k) from the two simulations. It is also verified that the Green-Kubo relation can still yield an accurate measure of the static viscosity {eta} in the presence of a modest level of friction as in dusty plasma experiments.

Feng Yan; Goree, J.; Liu Bin [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242 (United States)

2011-05-15T23:59:59.000Z

Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Correlated changes in structure and viscosity during gelatinization and gelation of tapioca starch granules  

Science Journals Connector (OSTI)

Melting of the semicrystalline structure of native tapioca starch granules is correlated to solution viscosity for elucidating gelatinization and gelation processes.

Huang, H.-K.

2014-10-21T23:59:59.000Z

442

E-Print Network 3.0 - assess viscosity reduction Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

final spread as well as the stopping time... time with viscosity. Key words: self compacting concrete, rheology, slump flow, yield stress Source: Georgiou, Georgios - Department...

443

What Are the Limitations of Braginskii's Fluid Equations and Hazeltine's Drift Kinetic Equation?  

SciTech Connect (OSTI)

The two-fluid equations of Braginskii miss heat-flux terms in the viscosity. In this work we employ drift orderings to recover these missing terms and obtain a fully self-consistent system of short mean-free path two-fluid equations. These equations cannot be recovered from the short mean-free path limit of the well-known drift kinetic formalism of Hazeltine since this formalism is only accurate through first order in the small gyroradius expansion parameter, whereas second order accuracy is required. We propose a way of generalizing this formalism to make it second-order accurate. We also use the results to derive the gyroviscosity and ion perpendicular viscosity for plasmas of arbitrary collisionality, provided the leading order distribution function is velocity-space isotropic. As an application, we consider electrostatic turbulence in a tokamak and use our expressions for ion viscosity in the toroidal angular momentum conservation equation to show that the ion perpendicular viscosity can be important for determining the axisymmetric radial electric field (and, therefore, zonal flow amplitude), especially if the turbulent radial particle flux is small.

Simakov, Andrei N. [Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); Catto, Peter J. [MIT Plasma Science and Fusion Center, Cambridge, MA 02139 (United States)

2006-11-30T23:59:59.000Z

444

Fiber optic fluid detector  

DOE Patents [OSTI]

Particular gases or liquids are detected with a fiber optic element having a cladding or coating of a material which absorbs the fluid or fluids and which exhibits a change of an optical property, such as index of refraction, light transmissiveness or fluoresence emission, for example, in response to absorption of the fluid. The fluid is sensed by directing light into the fiber optic element and detecting changes in the light, such as exit angle changes for example, that result from the changed optical property of the coating material. The fluid detector may be used for such purposes as sensing toxic or explosive gases in the atmosphere, measuring ground water contamination or monitoring fluid flows in industrial processes, among other uses. 10 figs.

Angel, S.M.

1987-02-27T23:59:59.000Z

445

Viscous potential flow analysis of electrified miscible finitely conducting fluid through porous media  

SciTech Connect (OSTI)

In this work, a viscous potential flow analysis is used to investigate capillary surface waves between two horizontal finite fluid layers. The two layers have finite conductivities and admit mass and heat transfer. A general dispersion relation is derived. The presence of finite conductivities together with the dielectric permeabilities makes the horizontal electric field play a dual role in the stability criterion. The phenomenon of negative viscosity is observed. A new growth rate parameter, depending on the kinematical viscosity of the lower fluid layer, is found and has a stabilizing effect on the unstable modes. The growth rates and neutral stability curve are given and applied to air-water interface. The effects of various parameters are discussed for the Kelvin-Helmholtz and the Rayleigh-Taylor instabilities.

Obied Allah, M. H. [Department of Mathematics, Faculty of Science, Assiut University, Assiut (Egypt)

2013-04-15T23:59:59.000Z

446

Effect of Resins and DBSA on Asphaltene Precipitation from Petroleum Fluids  

E-Print Network [OSTI]

Effect of Resins and DBSA on Asphaltene Precipitation from Petroleum Fluids Lamia Goual and Abbas different petroleum fluids. Various resins are added to three different petroleum fluids to measure of precipitation. However, addition of resins to a petroleum fluid increases the amount of precipitated asphaltenes

Firoozabadi, Abbas

447

Frequency-dependent processing and interpretation (FDPI) of seismic data for identifying, imaging and monitoring fluid-saturated underground reservoirs  

DOE Patents [OSTI]

A method for identifying, imaging and monitoring dry or fluid-saturated underground reservoirs using seismic waves reflected from target porous or fractured layers is set forth. Seismic imaging the porous or fractured layer occurs by low pass filtering of the windowed reflections from the target porous or fractured layers leaving frequencies below low-most corner (or full width at half maximum) of a recorded frequency spectra. Additionally, the ratio of image amplitudes is shown to be approximately proportional to reservoir permeability, viscosity of fluid, and the fluid saturation of the porous or fractured layers.

Goloshubin, Gennady M. (Sugar Land, TX); Korneev, Valeri A. (Lafayette, CA)

2005-09-06T23:59:59.000Z

448

QCD Viscosity to Entropy Density Ratio in the Hadronic Phase  

E-Print Network [OSTI]

Shear viscosity (eta) of QCD in the hadronic phase is computed by the coupled Boltzmann equations of pions and nucleons in low temperatures and low baryon number densities. The eta to entropy density ratio eta/s maps out the nuclear gas-liquid phase transition by forming a valley tracing the phase transition line in the temperature-chemical potential plane. When the phase transition turns into a crossover, the eta/s valley gradually disappears. We suspect the general feature for a first-order phase transition is that eta/s has a discontinuity in the bottom of the eta/s valley. The discontinuity coincides with the phase transition line and ends at the critical point. Beyond the critical point, a smooth eta/s valley is seen. However, the valley could disappear further away from the critical point. The eta/s measurements might provide an alternative to identify the critical points.

Jiunn-Wei Chen; Yen-Han Li; Yen-Fu Liu; Eiji Nakano

2007-03-21T23:59:59.000Z

449

Hall viscosity to entropy ratio in higher derivative theories  

E-Print Network [OSTI]

In this paper based on the basic principles of gauge/gravity duality we compute the hall viscosity to entropy ratio in the presence of various higher derivative corrections to the dual gravitational description embedded in an asymptotically $ AdS_{4} $ space time. As the first step of our analysis, considering the back reaction we impose higher derivative corrections to the abelian gauge sector of the theory where we notice that the ratio indeed gets corrected at the leading order in the coupling. Considering the probe limit as a special case we compute this leading order correction over the fixed background of the charged black brane solution. Finally we consider higher derivative ($ R^{2} $) correction to the gravity sector of the theory where we notice that the above ratio might get corrected at the sixth derivative level.

Dibakar Roychowdhury

2014-08-21T23:59:59.000Z

450

Viscosity of the QGP from a virial expansion  

SciTech Connect (OSTI)

In this work we calculate the shear viscosity {eta} in the quark-gluon plasma within a virial expansion approach with particular interest in the ratio of {eta} to the entropy density s, i.e. {eta}/s. We derive a realistic equation of state using a virial expansion approach which allows us to include the interactions between the partons in the deconfined phase. From the interaction we directly extract the effective coupling {alpha}{sub V} for the determination of {eta}. Our results for {eta}/s show a minimum near to T{sub c} very close with the lowest bound and, furthermore, in line with the experimental point from RHIC as well as with the lattice calculations.

Mattiello, S., E-mail: stefano.mattiello@theo.physik.uni-giessen.de [University of Giessen, Institute for Theoretical Physics (Germany)

2012-06-15T23:59:59.000Z

451

Asymmetric tearing mode in the presence of viscosity  

SciTech Connect (OSTI)

The linear stability of the tearing mode (TM) in a plasma column is investigated in the presence of viscosity and finite equilibrium current density gradients (i.e., asymmetries). It is shown that for low {beta}, both effects are essential in order to properly describe the mode behaviour close to marginality. In particular, the theory introduces a critical threshold for the destabilization, such that the perturbation grows only if {Delta}'>{Delta}'{sub cr}. The value of {Delta}'{sub cr} depends on the equilibrium configuration and on the plasma parameters. Most importantly, {Delta}'{sub cr} can take negative values, thus allowing unstable tearing modes for {Delta}' < 0 (even in the absence of bootstrap current).

Militello, F. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Borgogno, D. [Dipartimento di Energetica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Grasso, D. [CNR Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, Dipartimento di Energetica, Politecnico di Torino, 10129 Torino (Italy); Marchetto, C. [Associazione EURATOM-ENEA sulla Fusione, IFP-CNR, Via R. Cozzi 53, 20125 Milano (Italy); Ottaviani, M. [Association EURATOM-CEA, CEA/DSM/IRFM, CEA Cadarache, 13108 St. Paul-lez-Durance (France)

2011-11-15T23:59:59.000Z

452

Determining circulating fluid temperature in drilling, workover, and well-control operations  

SciTech Connect (OSTI)

Estimation of fluid temperature in both flow conduits (drillpipe or tubing and the annulus) is required to ascertain the fluid density and viscosity and, in turn, to calculate the pressure drop or the maximum allowable pumping rate for a number of operations. These operations include drilling, workover, and well control. The fluid temperature estimation becomes critical for high-temperature or geothermal reservoirs where significant heat exchange occurs or when fluid properties are temperature sensitive, such as for a non-Newtonian fluid. In this work, the authors present an analytical model for the flowing fluid temperature in the drillpipe/tubing and in the annulus as a function of well depth and circulation time. The model is based on an energy balance between the formation and the fluid in the drillpipe.tubing and annulus. Steady-state heat transfer is assumed in the wellbore while transient heat transfer takes place in the formation. solutions are obtained for two possible scenarios: (1) the fluid flows down the annulus and up the drillpipe/tubing, and (2) the fluid flows down the tubing and up the annulus. The analytic model developed is cast in a set of simple algebraic equations for rapid implementation. The authors also show that the maximum temperature occurs not at the well bottom, but at some distance higher from the bottom for flow up the annulus.

Kabir, C.S. [Chevron Overseas Petroleum Technology Co. (Kuwait); Hasan, A.R.; Ameen, M.M. [Univ. of North Dakota, Grand Forks, ND (United States); Kouba, G.E.

1996-06-01T23:59:59.000Z

453

Thermodynamics and Fluids  

Science Journals Connector (OSTI)

... AN important section of the work of modern chemical engineers lies in the application of thermodynamics to problems of fluid systems. This volume, the fourth in the series, is ... properties of physical systems and to the transport properties of fluids. The first section on thermodynamics has been written by Dr. R. Strickland Constable of the Chemical Engineering Department at ...

J. M. COULSON

1958-09-27T23:59:59.000Z

454

ARRHENIUS MODEL FOR HIGH-TEMPERATURE GLASS VISCOSITY WITH A CONSTANT PRE-EXPONENTIAL FACTOR  

SciTech Connect (OSTI)

A simplified form of the Arrhenius equation, ln ? = A + B(x)/T, where ? is the viscosity, T the temperature, x the composition vector, and A and B the Arrhenius coefficients, was fitted to glass-viscosity data for the processing temperature range (the range at which the viscosity is within 1 to 103 Pa.s) while setting A = constant and treating B(x) as a linear function of mass fractions of major components. Fitting the Arrhenius equation to over 550 viscosity data of commercial glasses and approximately 1000 viscosity data of glasses for nuclear-waste glasses resulted in the A values of -11.35 and -11.48, respectively. The R2 value ranged from 0.92 to 0.99 for commercial glasses and was 0.98 for waste glasses. The Arrhenius models estimate viscosities for melts of commercial glasses containing 42 to 84 mass% SiO2 within the temperature range of 1100 to 1550°C and viscosity range of 5 to 400 Pa.s and for waste glasses containing 32 to 60 mass% SiO2 within the temperature range of 850 to 1450°C and viscosity range of 0.4 to 250 Pa.s.

Hrma, Pavel R.

2008-04-15T23:59:59.000Z

455

Shear viscosity from R-charged AdS black holes  

E-Print Network [OSTI]

We compute the shear viscosity in the supersymmetric Yang-Mills theory dual to the STU background. This is a thermal gauge theory with a chemical potential. The quotient of the shear viscosity over the entropy density exhibits no deviation from the well known result 1/4\\pi.

J. Mas

2006-01-20T23:59:59.000Z

456

Role of viscosity in the accurate prediction of source-terms for high molecular weight substances  

E-Print Network [OSTI]

and pressure, and mixing effects. The viscosity prediction uses an improvement on current predictions by combining b-parameter and Modified Chung-Lee-starling (MCLS) viscosity predictions for the employed pseudo-mixtures. The source-term model used is SPILLS...

Shaikh, Irfan Yusuf

2012-06-07T23:59:59.000Z

457

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

DOE Patents [OSTI]

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

Tiegs, T.N.; Wittmer, D.E.

1995-10-10T23:59:59.000Z

458

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

DOE Patents [OSTI]

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

Tiegs, Terry N. (Lenoir City, TN); Wittmer, Dale E. (Carbondale, IL)

1995-01-01T23:59:59.000Z

459

Plateau Field Test of Diesel Engine Oils with Different Viscosity Grades  

Science Journals Connector (OSTI)

The degradation of SF/CD 0W/30, CD5W/30 and SF/CD 15W/40 general engine oils has been investigated by Plateau field test with STYER 91 trucks. The experimental results have shown that on the Plateau viscosity grade of the oil hardly impacts on its service ... Keywords: Plateau, field test, viscosity grade, oil, diesel engine

Su Bin; Shi Yonggang; Gong Haifeng; Xu Jinlong; Wei Wei; Mei Lin

2011-01-01T23:59:59.000Z

460

Effects of Thermal Exposure and Test Temperature on Structure Evolution and Hardness/Viscosity  

E-Print Network [OSTI]

Effects of Thermal Exposure and Test Temperature on Structure Evolution and Hardness/Viscosity the physical and mechanical properties (i.e., viscosity, flow, and fracture). In some cases, the thermal coating techniques (e.g., high velocity oxygen fuel (HVOF), plasma spray, cold spray, etc.) have been used

Rollins, Andrew M.

Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Optical fiber-based fluorescent viscosity sensor Mark A. Haidekker and Walter J. Akers  

E-Print Network [OSTI]

Optical fiber-based fluorescent viscosity sensor Mark A. Haidekker and Walter J. Akers Department bound to a fiber-optic tip without loss of viscosity sensi- tivity. The optical fiber itself may be used to molecular rotors in solution. An optical fiber-based fluorescent vis- cosity sensor may be used in real

Theodorakis, Emmanuel

462

A parameter sensitivity analysis using an EOS for optimal characterization of Cupiagua reservoir fluids  

E-Print Network [OSTI]

PARAMETER FOR HYDROCARBONS . . . . Page 3. 1- PVT SUMMARY. . . . . . 46 3. 2- 3. 3- RECOMBINED FLUID COMPOSITION- CUPIAGUA A1 CCE AT 242eF AND 244eF ? CUPIAGUA Al . . . . . . . . . , 49 . . . . . . . 50 3. 4- CVD AT 242eF ? CUPIAGUA Al (UPPER.... 10- CCE AT 1500F, 240eF AND 247eF ? CUPIAGUA C3 . . . . . CVD AT 247eF - CUPIAGUA C3. MULTISTAGE SEPARATOR SUMMARY- CUPIAGUA C3. . . . . 54 . . . . 55 . . . . 55 3. 11- FLUID VISCOSITY AT 247 F ? CUPIAGUA C3 . . . . . . . . . 55 3. 12...

Florez, Alberto

1998-01-01T23:59:59.000Z

463

MAX Fluid Dynamics facility  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

MAX Fluid Dynamics facility MAX Fluid Dynamics facility Capabilities Engineering Experimentation Reactor Safety Testing and Analysis Overview Nuclear Reactor Severe Accident Experiments MAX NSTF SNAKE Aerosol Experiments System Components Laser Applications Robots Applications Other Facilities Other Capabilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr MAX Fluid Dynamics facility Providing high resolution data for development of computational tools that model fluid flow and heat transfer within complex systems such as the core of a nuclear reactor. 1 2 3 4 5 Hot and cold air jets are mixed within a glass tank while laser-based anemometers and a high-speed infrared camera characterize fluid flow and heat transfer behavior. Click on image to view larger size image.

464

Viscosity effects on waves in partially and fully ionized plasma in magnetic field  

E-Print Network [OSTI]

Viscosity is discussed in multicomponent partially and fully ionized plasma, and its effects on two very different waves (Alfven and Langmuir) in solar atmosphere. A full set of viscosity coefficients is presented which includes coefficients for electrons, protons and hydrogen atoms. These are applied to layers with mostly magnetized protons in solar chromosphere where the Alfven wave could in principle be expected. The viscosity coefficients are calculated and presented graphically for the altitudes between 700 and 2200 km, and required corresponding cross sections for various types of collisions are given in terms of altitude. It is shown that in chromosphere the viscosity plays no role for the Alfven wave, which is only strongly affected by ion friction with neutrals. In corona, assuming the magnetic field of a few Gauss, the Alfven wave is more affected by ion viscosity than by ion-electron friction only for wavelengths shorter that 1-30 km, dependent on parameters and assuming the perturbed magnetic fiel...

Vranjes, J

2014-01-01T23:59:59.000Z

465

Fluid sampling system  

DOE Patents [OSTI]

An fluid sampling system allows sampling of radioactive liquid without spillage. A feed tank is connected to a liquid transfer jet powered by a pumping chamber pressurized by compressed air. The liquid is pumped upwardly into a sampling jet of a venturi design having a lumen with an inlet, an outlet, a constricted middle portion, and a port located above the constricted middle portion. The liquid is passed under pressure through the constricted portion causing its velocity to increase and its pressure to be decreased, thereby preventing liquid from escaping. A septum sealing the port can be pierced by a two pointed hollow needle leading into a sample bottle also sealed by a pierceable septum affixed to one end. The bottle is evacuated by flow through the sample jet, cyclic variation in the sampler jet pressure periodically leaves the evacuated bottle with lower pressure than that of the port, thus causing solution to pass into the bottle. The remaining solution in the system is returned to the feed tank via a holding tank. 4 figs.

Houck, E.D.

1994-10-11T23:59:59.000Z

466

Tracing Geothermal Fluids  

SciTech Connect (OSTI)

Geothermal water must be injected back into the reservoir after it has been used for power production. Injection is critical in maximizing the power production and lifetime of the reservoir. To use injectate effectively the direction and velocity of the injected water must be known or inferred. This information can be obtained by using chemical tracers to track the subsurface flow paths of the injected fluid. Tracers are chemical compounds that are added to the water as it is injected back into the reservoir. The hot production water is monitored for the presence of this tracer using the most sensitive analytic methods that are economically feasible. The amount and concentration pattern of the tracer revealed by this monitoring can be used to evaluate how effective the injection strategy is. However, the tracers must have properties that suite the environment that they will be used in. This requires careful consideration and testing of the tracer properties. In previous and parallel investigations we have developed tracers that are suitable from tracing liquid water. In this investigation, we developed tracers that can be used for steam and mixed water/steam environments. This work will improve the efficiency of injection management in geothermal fields, lowering the cost of energy production and increasing the power output of these systems.

Michael C. Adams; Greg Nash

2004-03-01T23:59:59.000Z

467

J. Fluid Mech. (2012), vol. 690, pp. 94128. c Cambridge University Press 2011 94 doi:10.1017/jfm.2011.386  

E-Print Network [OSTI]

-4 percritical flows. However, thanks to the use of water-based fluids of vari-5 ous viscosity, our experiments show that a rhomboid pattern can develop in6 subcritical flows. Its angle is primarily a function the mark of a hydraulic phenomenon,10 but rather results from the coupling between the water flow

468

The Effect of Heavy Oil Viscosity Reduction by Solvent Dissolution on Natural Convection in the Boundary Layer of VAPEX  

Science Journals Connector (OSTI)

We have studied the effect of viscosity on natural convection in the boundary layer of the vapor extraction (VAPEX) process. VAPEX is a heavy oil recovery method that uses solvents to reduce oil viscosity, and...

Mohammad Javaheri; Jalal Abedi

2013-09-01T23:59:59.000Z

469

Fluid sampling tool  

DOE Patents [OSTI]

A fluid sampling tool is described for sampling fluid from a container. The tool has a fluid collecting portion which is drilled into the container wall, thereby affixing it to the wall. The tool may have a fluid extracting section which withdraws fluid collected by the fluid collecting section. The fluid collecting section has a fluted shank with an end configured to drill a hole into a container wall. The shank has a threaded portion for tapping the borehole. The shank is threadably engaged to a cylindrical housing having an inner axial passageway sealed at one end by a septum. A flexible member having a cylindrical portion and a bulbous portion is provided. The housing can be slid into an inner axial passageway in the cylindrical portion and sealed to the flexible member. The bulbous portion has an outer lip defining an opening. The housing is clamped into the chuck of a drill, the lip of the bulbous section is pressed against a container wall until the shank touches the wall, and the user operates the drill. Wall shavings (kerf) are confined in a chamber formed in the bulbous section as it folds when the shank advances inside the container. After sufficient advancement of the shank, an o-ring makes a seal with the container wall. 6 figs.

Garcia, A.R.; Johnston, R.G.; Martinez, R.K.

1999-05-25T23:59:59.000Z

470

IDENTIFYING FRACTURES AND FLUID TYPES USING FLUID INCLUSION STRATIGRAPHY |  

Open Energy Info (EERE)

IDENTIFYING FRACTURES AND FLUID TYPES USING FLUID INCLUSION STRATIGRAPHY IDENTIFYING FRACTURES AND FLUID TYPES USING FLUID INCLUSION STRATIGRAPHY Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: IDENTIFYING FRACTURES AND FLUID TYPES USING FLUID INCLUSION STRATIGRAPHY Details Activities (1) Areas (1) Regions (0) Abstract: Fluid Inclusion Stratigraphy (FIS) is a method currently being developed for use in geothermal systems to identify fractures and fluid types. This paper is the third in a series of papers on the development of FIS. Fluid inclusion gas chemistry is analyzed and plotted on well log diagrams. The working hypothesis is that select gaseous species and species ratios indicate areas of groundwater and reservoir fluid flow and reservoir seals. Previously we showed that FIS analyses identify fluid types and

471

Multiphase fluid characterization system  

DOE Patents [OSTI]

A measurement system and method for permitting multiple independent measurements of several physical parameters of multiphase fluids flowing through pipes are described. Multiple acoustic transducers are placed in acoustic communication with or attached to the outside surface of a section of existing spool (metal pipe), typically less than 3 feet in length, for noninvasive measurements. Sound speed, sound attenuation, fluid density, fluid flow, container wall resonance characteristics, and Doppler measurements for gas volume fraction may be measured simultaneously by the system. Temperature measurements are made using a temperature sensor for oil-cut correction.

Sinha, Dipen N.

2014-09-02T23:59:59.000Z

472

Br-Cl-Na systematics in Illinois basin fluids: Constraints on fluid origin and evolution  

SciTech Connect (OSTI)

The authors present here bromide, chloride, and sodium data for fluids from reservoirs of Ordovician through Pennsylvania age in the Illinois basic which suggest that remnant marine fluids contribute significantly to fluid Cl budgets. Cl/Br and NaBr ratios for Ordovician through Devonian formation fluids are relatively uniform and near those for seawater, despite greater than a factor of ten range in Cl concentration. In contrast, fluids from Mississippian and Pennsylvanian reservoirs, separated from older reservoirs by the New Albany Shale Group, have more variable fluid Cl/Br and Na/Br ratios, most of which are significantly greater then those of seawater. The 1:1 stoichiometry of Cl and Na increases for Mississippian and Pennsylvanian formation fluids is consistent with halite dissolution. Nevertheless, Br systematics and mass-balance considerations indicate that he overall Cl budget of Illinois basin formation fluids appears to be more significantly influenced by the contribution from subaerially evaporated seawater than by halite dissolution.

Walter, L.M.; Huston, T.J. (Washington Univ., St. Louis, Missouri (USA)); Stueber, A.M. (Southern Illinois Univ., Edwardsville (USA))

1990-04-01T23:59:59.000Z

473

Selection and analytical monitoring of backing pump fluids in semiconductor processes  

Science Journals Connector (OSTI)

Fluids in backing pumps must fulfill the following tasks: sealing lubricating protection against corrosion and the transportation of heat. In semiconductor processes additional demands are made on a pump fluid. It must be resistant to reactive substances. For the different processes such as etching chemical vapor deposition etc. different classes of fluids have proved to be effective in practice. This makes specific adaptation to a process possible. Regular control of the fluid is necessary to achieve safe operation. In general the quality of a fluid is controlled by determining its viscosity the total acid number and total base number and its ash content and an optical evaluation is made. With pump fluids coming from semiconductor processes specific analytical problems arise which require special treatment and analysis. Filtration extraction adsorption and degassing are good methods for treatment. The determination of decomposition products of the fluid and substances from the process chamber can be effected with the help of infrared spectroscopy. In addition mass spectroscopy elementary analysis and other chemical methods can be helpful in evaluating a pumping fluid.

Monika Kuhn; Paul Bachmann

1987-01-01T23:59:59.000Z

474

Viscosity and radial distribution function in PbxSe(1-x) melts for stoechiometric and peritectic compositions  

E-Print Network [OSTI]

L-529 Viscosity and radial distribution function in PbxSe(1-x) melts for stoechiometric by lead atoms sur- rounded by Se atoms are considered. Kinematic viscosity data are compared a molecular structure in the liquid state rather than a chain-structure [1]. Viscosity is very sensitive

Paris-Sud XI, Université de

475

Viscosity of an electro-rheological suspension with internal rotations. E. Lemaire, L.Lobry, N. Pannacci, F.Peters  

E-Print Network [OSTI]

1 Viscosity of an electro-rheological suspension with internal rotations. E. Lemaire, L.Lobry, N (Quincke rotation) which, in turn, leads to a drastic decrease of the apparent viscosity of the suspension. The purpose of the paper is to provide a relation between the apparent viscosity of the suspension and the E

Boyer, Edmond

476

Viscosity of the Aqueous Liquid/Vapor Interfacial Region: 2D Electrochemical Measurements with a Piperidine Nitroxy  

E-Print Network [OSTI]

Viscosity of the Aqueous Liquid/Vapor Interfacial Region: 2D Electrochemical Measurements, and that it is coupled to the interfacial water via hydrogen bonding with H2O. In view of this postulate, the viscosity into the dynamic characteristics of aqueous interfaces. Thus, parameters such as the viscosity of water

Majda, Marcin

477

MAGNETOHYDRODYNAMIC SIMULATIONS OF THE FORMATION OF COLD FRONTS IN CLUSTERS OF GALAXIES: EFFECTS OF ANISOTROPIC VISCOSITY  

SciTech Connect (OSTI)

We carried out three-dimensional magnetohydrodynamic simulations to study the effects of plasma viscosity on the formation of sharp discontinuities of density and temperature distributions, cold fronts, in clusters of galaxies. By fixing the gravitational potential that confines the cool, dense plasma in a moving subcluster, we simulated its interaction with the hot, lower density plasma around the subcluster. At the initial state, the intracluster medium (ICM) is assumed to be threaded by uniform magnetic fields. The enhancement of plasma viscosity along the direction of magnetic fields is incorporated as anisotropic viscosity depending on the direction of magnetic fields. We found that the Kelvin-Helmholtz instability at the surface of the subcluster grows even in models with anisotropic viscosity, because its effects on the velocity shear across the magnetic field lines are suppressed. We also found that magnetic fields around the interface between the subcluster and ICM are amplified even in the presence of viscosity, while magnetic fields behind the subcluster are amplified up to {beta}{sup -1} {approx} 0.01 in models with viscosity, whereas they are amplified up to {beta}{sup -1} {approx} 0.1 in models without viscosity, where {beta} is the ratio of gas pressure to magnetic pressure.

Suzuki, Kentaro; Ogawa, Takayuki; Matsumoto, Yosuke; Matsumoto, Ryoji, E-mail: suzukikn@astro.s.chiba-u.ac.jp, E-mail: ogawa@astro.s.chiba-u.ac.jp, E-mail: ymatumot@astro.s.chiba-u.ac.jp, E-mail: matumoto@astro.s.chiba-u.ac.jp [Department of Physics, Graduate School of Science, Chiba University, Inage-ku, Chiba 263-8522 (Japan)

2013-05-10T23:59:59.000Z

478

Rotational viscometer for high-pressure, high-temperature fluids  

DOE Patents [OSTI]

The invention is a novel rotational viscometer which is well adapted for use with fluids at high temperatures and/or pressures. In one embodiment, the viscometer include a substantially non-magnetic tube having a closed end and having an open end in communication with a fluid whose viscosity is to be determined. An annular drive magnet is mounted for rotation about the tube. The tube encompasses and supports a rotatable shaft assembly which carries a rotor, or bob, for insertion in the fluid. Affixed to the shaft are (a) a second magnet which is magnetically coupled to the drive magnet and (b) a third magnet. In a typical operation, the drive magnet is rotated to turn the shaft assembly while the shaft rotor is immersed in the fluid. The viscous drag on the rotor causes the shaft assembly to lag the rotation of the drive magnet by an amount which is a function of the amount of viscous drag. A first magnetic pickup generates a waveform whose phase is a function of the angular position of the drive magnet. A second magnetic pickup generates a waveform whose phase is a function of the angular position of the third magnet. Means are provided to generate an output indicative of the phase difference between the two waveforms. The viscometer is comparatively simple, inexpensive, rugged, and does not require shaft seals.

Carr, K.R.

1983-06-06T23:59:59.000Z

479

Numerical implication of Riemann problem theory for fluid dynamics  

SciTech Connect (OSTI)

The Riemann problem plays an important role in understanding the wave structure of fluid flow. It is also crucial step in some numerical algorithms for accurately and efficiently computing fluid flow; Godunov method, random choice method, and from tracking method. The standard wave structure consists of shock and rarefaction waves. Due to physical effects such as phase transitions, which often are indistinguishable from numerical errors in an equation of state, anomalkous waves may occur, ''rarefaction shocks'', split waves, and composites. The anomalous waves may appear in numerical calculations as waves smeared out by either too much artificial viscosity or insufficient resolution. In addition, the equation of state may lead to instabilities of fluid flow. Since these anomalous effects due to the equation of state occur for the continuum equations, they can be expected to occur for all computational algorithms. The equation of state may be characterized by three dimensionless variables: the adiabatic exponent ..gamma.., the Grueneisen coefficient GAMMA, and the fundamental derivative G. The fluid flow anomalies occur when inequalities relating these variables are violated. 18 refs.

Menikoff, R.

1988-01-01T23:59:59.000Z

480

Fluid pumping apparatus  

DOE Patents [OSTI]

A method and apparatus suitable for coupling seismic or other downhole sensors to a borehole wall in high temperature and pressure environments. In one embodiment, one or more metal bellows mounted to a sensor module are inflated to clamp the sensor module within the borehole and couple an associated seismic sensor to a borehole wall. Once the sensing operation is complete, the bellows are deflated and the sensor module is unclamped by deflation of the metal bellows. In a further embodiment, a magnetic drive pump in a pump module is used to supply fluid pressure for inflating the metal bellows using borehole fluid or fluid from a reservoir. The pump includes a magnetic drive motor configured with a rotor assembly to be exposed to borehole fluid pressure including a rotatable armature for driving an impeller and an associated coil under control of electronics isolated from borehole pressure.

West, Phillip B. (Idaho Falls, ID)

2006-01-17T23:59:59.000Z

Note: This page contains sample records for the topic "fluid viscosity increases" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

Basic fluid system trainer  

DOE Patents [OSTI]

A trainer, mounted and housed within a mobile console, is used to teach and reinforce fluid principles to students. The system trainer has two centrifugal pumps, each driven by a corresponding two-speed electric motor. The motors are controlled by motor controllers for operating the pumps to circulate the fluid stored within a supply tank through a closed system. The pumps may be connected in series or in parallel. A number of valves are also included within the system to effect different flow paths for the fluid. In addition, temperature and pressure sensing instruments are installed throughout the closed system for measuring the characteristics of the fluid, as it passes through the different valves and pumps. These measurements are indicated on a front panel mounted to the console, as a teaching aid, to allow the students to observe the characteristics of the system.

Semans, Joseph P. (Uniontown, PA); Johnson, Peter G. (Pittsburgh, PA); LeBoeuf, Jr., Robert F. (Clairton, PA); Kromka, Joseph A. (Idaho Falls, ID); Goron, Ronald H. (Connellsville, PA); Hay, George D. (Venetia, PA)

1993-01-01T23:59:59.000Z

482

Heat transfer through convection in a quasi-one-dimensional magnetic fluid  

Science Journals Connector (OSTI)

A magnetic fluid consists of magnetic nanoparticles suspended in nonmagnetic ... is observed in a quasi-one-dimensional magnetic fluid in a horizontal temperature gradient. The local...T..., increases with increa...

Jun Huang; Weili Luo

2013-08-01T23:59:59.000Z

483

Thermoporoelastic Effects of Drilling Fluid Temperature on Rock Drillability at Bit/Formation Interface  

E-Print Network [OSTI]

effects of the drilling fluid temperature on near-wellbore stresses. At the bottomhole area, a cool drilling fluid reduces the radial and tangential effective stresses in formation, whereas the vertical effective stress increases. The outcome is a possible...

Thepchatri, Kritatee 1984-

2012-10-26T23:59:59.000Z

484

GEOTHERMAL FLUID PROPENE AND PROPANE: INDICATORS OF FLUID | Open Energy  

Open Energy Info (EERE)

FLUID PROPENE AND PROPANE: INDICATORS OF FLUID FLUID PROPENE AND PROPANE: INDICATORS OF FLUID Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: GEOTHERMAL FLUID PROPENE AND PROPANE: INDICATORS OF FLUID Details Activities (1) Areas (1) Regions (0) Abstract: The use of fluid inclusion gas analysis propene/propene ratios is investigated. Ratios of these species are affected by geothermal fluid temperature and oxidations state. Our purpose is to determine if analyses of these species in fluid inclusions these species to can be used to interpret fluid type, history, or process. Analyses were performed on drill cuttings at 20ft intervals from four Coso geothermal wells. Two wells are good producers, one has cold-water entrants in the production zone, and the fourth is a non-producer. The ratios show distinct differences between

485

Shear viscosity of two-dimensional Yukawa systems in liquid state  

E-Print Network [OSTI]

The shear viscosity of a two-dimensional (2D) liquid was calculated using equilibrium molecular dynamics simulations with a Yukawa potential. The shear viscosity has a minimum, at a Coulomb coupling parameter of about 17, arising from the temperature dependence of the kinetic and potential contributions. Previous calculations of 2D viscosity were less extensive, and for a different potential. The stress autocorrelation function was found to decay rapidly, contrary to some earlier work. These results are useful for 2D condensed matter systems and are compared to a recent dusty plasma experiment.

Bin Liu; J. Goree

2005-01-31T23:59:59.000Z

486

Neutron scattering studies of crude oil viscosity reduction with electric field  

Science Journals Connector (OSTI)

Abstract The small angle neutron scattering experiment has confirmed the theoretical prediction that a strong electric field induces the suspended nano-particles inside crude oil to aggregate into short chains along the field direction. This aggregation breaks the symmetry, making the viscosity anisotropic: along the field direction, the viscosity is significantly reduced. The experiment enables us to determine the induced chain size and shape, verifies that the electric field works for all kinds of crude oils, paraffin-based, asphalt-based, and mix-based. The basic physics of such field induced viscosity reduction is applicable to all kinds of suspensions.

R. Tao; E. Du; H. Tang; X. Xu

2014-01-01T23:59:59.000Z

487

Influence of Shear Viscosity of Quark-Gluon Plasma on Elliptic Flow in Ultrarelativistic Heavy-Ion Collisions  

SciTech Connect (OSTI)

We investigate the influence of a temperature-dependent shear viscosity over entropy density ratio {eta}/s on the transverse momentum spectra and elliptic flow of hadrons in ultrarelativistic heavy-ion collisions. We find that the elliptic flow in {radical}(s{sub NN})=200 GeV Au+Au collisions at RHIC is dominated by the viscosity in the hadronic phase and in the phase transition region, but largely insensitive to the viscosity of the quark-gluon plasma (QGP). At the highest LHC energy, the elliptic flow becomes sensitive to the QGP viscosity and insensitive to the hadronic viscosity.

Niemi, H. [Frankfurt Institute for Advanced Studies, Ruth-Moufang-Strasse 1, D-60438 Frankfurt am Main (Germany); Denicol, G. S.; Huovinen, P. [Institut fuer Theoretische Physik, Johann Wolfgang Goethe-Universitaet, Max-von-Laue-Strasse 1, D-60438 Frankfurt am Main (Germany); Molnar, E. [Frankfurt Institute for Advanced Studies, Ruth-Moufang-Strasse 1, D-60438 Frankfurt am Main (Germany); MTA-KFKI, Research Institute for Particle and Nuclear Physics, H-1525 Budapest, P.O. Box 49 (Hungary); Rischke, D. H. [Frankfurt Institute for Advanced Studies, Ruth-Moufang-Strasse 1, D-60438 Frankfurt am Main (Germany); Institut fuer Theoretische Physik, Johann Wolfgang Goethe-Universitaet, Max-von-Laue-Strasse 1, D-60438 Frankfurt am Main (Germany)

2011-05-27T23:59:59.000Z

488

Tailored Working Fluids for Enhanced Binary Geothermal Power Plants  

Broader source: Energy.gov [DOE]

DOE Geothermal Program Peer Review 2010 - Presentation. Project Objective: To improve the utilization of available energy in geothermal resources and increase the energy conversion efficiency of systems employed by a) tailoring the subcritical and/or supercritical glide of enhanced working fluids to best match thermal resources, and b) identifying appropriate thermal system and component designs for the down-selected working fluids.

489

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

SciTech Connect (OSTI)

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

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

2013-12-15T23:59:59.000Z

490

Medium effects and the shear viscosity of the dilute Fermi gas away from the conformal limit  

E-Print Network [OSTI]

We study the shear viscosity of a dilute Fermi gas as a function of the scattering length in the vicinity of the unitarity limit. The calculation is based on kinetic theory, which provides a systematic approach to transport properties in the limit in which the fugacity $z=n\\lambda^3/2$ is small. Here, $n$ is the density of the gas and $\\lambda$ is the thermal wave length of the fermions. At leading order in the fugacity expansion the shear viscosity is independent of density, and the minimum shear viscosity is achieved at unitarity. At the next order medium effects modify the scattering amplitude as well as the quasi-particle energy and velocity. We show that these effects shift the minimum of the shear viscosity to the Bose-Einstein condensation (BEC) side of the resonance, in agreement with the result of recent experiments.

Bluhm, Marcus

2014-01-01T23:59:59.000Z

491

Viscosity, Shear Waves, and Atomic-Level Stress-Stress Correlations  

SciTech Connect (OSTI)

The Green-Kubo equation relates the macroscopic stress-stress correlation function to a liquid's viscosity. The concept of the atomic-level stresses allows the macroscopic stress-stress correlation function in the equation to be expressed in terms of the space-time correlations among the atomic-level stresses. Molecular dynamics studies show surprisingly long spatial extension of stress-stress correlations and also longitudinal and transverse waves propagating in liquids over ranges which could exceed the system size. The results reveal that the range of propagation of shear waves corresponds to the range of distances relevant for viscosity. Thus our results show that viscosity is a fundamentally nonlocal quantity. We also show that the periodic boundary conditions play a nontrivial role in molecular dynamics simulations, effectively masking the long-range nature of viscosity.

Levashov, Valentin A [ORNL; Morris, James R [ORNL; Egami, Takeshi [ORNL

2011-01-01T23:59:59.000Z

492

QGP viscosity at RHIC and the LHC - a 2012 status report  

E-Print Network [OSTI]

In this article, we briefly review the recent progress related to extracting the quark-gluon plasma (QGP) specific shear viscosity from the flow data measured at Relativistic Heavy-Ion Collider (RHIC) and the Large Hadron Collider (LHC).

Huichao Song

2012-10-21T23:59:59.000Z

493

Density, Speed of Sound, and Viscosity Measurements of Reference Materials for Biofuels  

Science Journals Connector (OSTI)

Measurements of density, speed of sound, and viscosity have been carried out on liquid certified reference materials for biofuels as a function of temperature at ambient pressure. The samples included anhydrous and hydrated bioethanol and two biodiesel ...

Arno Laesecke; Tara J. Fortin; Jolene D. Splett

2012-02-10T23:59:59.000Z

494

An extension of Pedersen's viscosity model for saturated black oil systems  

E-Print Network [OSTI]

) December 2000 Major Subject: Petmleum Engineering ABSTRACT An Extension of Pederscn's Viscosity Model lor Saturated Black Oil Systems. (December 2000) Adeyemi Adejuwon, M. Eng. , University ol' Surrey, United Kingdom Chair of Advisory Committee: Dr...

Adejuwon, Adeyemi

2012-06-07T23:59:59.000Z

495

Biodegradation of asphalt by Garciaella petrolearia TERIG02 for viscosity reduction of heavy oil  

Science Journals Connector (OSTI)

Petroleum hydrocarbon is an important energy resource, but it is difficult to exploit due to the presence of dominated heavy constituents such as asphaltenes. In this study, viscosity reduction of Jodhpur heav...

Meeta Lavania; Simrita Cheema; Priyangshu Manab Sarma; Ajoy Kumar Mandal…

2012-02-01T23:59:59.000Z

496

Effects of lubricant viscosity and surface texturing on ring-pack performance in internal combustion engines  

E-Print Network [OSTI]

The piston ring-pack contributes approximately 25% of the mechanical losses in an internal combustion engine. Both lubricant viscosity and surface texturing were investigated in an effort to reduce this ring-pack friction ...

Takata, Rosalind (Rosalind Kazuko), 1978-

2006-01-01T23:59:59.000Z

497

Effects of petroleum distillate on viscosity, density and surface tension of intermediate and heavy crude oils  

E-Print Network [OSTI]

Experimental and analytical studies have been carried out to better understand the effects of additives on viscosity, density and surface tension of intermediate and heavy crude oils. The studies have been conducted for the following oil samples...

Abdullayev, Azer

2009-06-02T23:59:59.000Z

498

Effect of glass composition on activation energy of viscosity in glass-melting-temperature range  

SciTech Connect (OSTI)

In the high-temperature range, where the viscosity (Eta) of molten glass is <10{sup 3} Pa s, the activation energy (B) is virtually ln(Eta) = A + B/T, is nearly independent of melt composition. Hence, the viscosity-composition relationship for Eta < 10{sup 3} Pa s is defined by B as a function of composition. Using a database encompassing over 1300 compositions of high-level waste glasses with nearly 7000 viscosity data, we developed mathematical models for B(x), where x is the composition vector in terms of mass fractions of components. In this paper, we present 13 versions of B(x) as first- and second-order polynomials with coefficients for 15 to 39 components, including Others, a component that sums constituents having little effect on viscosity.

Hrma, Pavel R.; Han, Sang Soo

2012-08-01T23:59:59.000Z

499

Density, Viscosity, Refractive Index and Conductivity of 1-Allyl-3-methylimidazolium Chloride + Water Mixture  

Science Journals Connector (OSTI)

Density, Viscosity, Refractive Index and Conductivity of 1-Allyl-3-methylimidazolium Chloride + Water Mixture† ... The data obtained will play an important supplementary function in completion of the ionic liquids database. ...

Di Wu; Bo Wu; Yu M. Zhang; Hua P. Wang

2009-10-22T23:59:59.000Z

500

The effective approach for predicting viscosity of saturated and undersaturated reservoir oil  

E-Print Network [OSTI]

Predicting reservoir oil viscosity with numerical correlation equations using field-measured variables is widely used in the petroleum industry. Most published correlation equations, however, have never profoundly realized the genuine relationship...

Kulchanyavivat, Sawin

2006-04-12T23:59:59.000Z