scholarly journals The viscosity of dilute solutions of strong electrolytes

1931 ◽  
Vol 134 (824) ◽  
pp. 413-427 ◽  
Keyword(s):  
Empirical Equation ◽  
Relative Viscosity ◽  
Theoretical Treatment ◽  
High Dilution ◽  
Equivalent Concentration ◽  
Pure Solvent ◽  
Wide Range ◽  
Strong Electrolytes ◽  
Negative Viscosity ◽  
Stiffening Effect

Until very recently, no empirical equation had been found to represent satisfactorily the variation with concentration of the relative viscosity of electrolytes, nor had any adequate theoretical treatment of the problem been put forward. In 1929, however, Jones and Dole showed that the fluidity (or reciprocal of the relative viscosity) of a salt solution could be represented over a fairly wide range of concentration by an equation of the form ϕ = 1 + A√ c +B c , where ϕ is the fluidity, c the equivalent concentration, and A and B are empirical constants. The value of B is negative in the case of salts which increase the viscosity of water, and positive in cases of so-called “negative viscosity,” where the viscosity of the solution is less than that of the pure solvent. Jones and Dole argued further that the stiffening effect of the interionic forces would tend to make the constant A, which determines the viscosity at high dilution, always negative. A little later, Falkenhagen and Dole treated the problem theoretically from the standpoint of the ion-atmosphere theory of Debye and Huckel. They confirmed the suggestion that at high dilution the electrolyte must always increase the viscosity of the solvent, and showed that the relative viscosity of an electrolyte solution at high dilution must be represented by an equation of the form η μ / η 0 = 1 + K √ μ , where η μ is the viscosity of the solution, η 0 is the viscosity of the solvent, μ is the equivalent concentration, K is a constant.

scholarly journals The viscosity of strong electrolytes measured by a differential method

1934 ◽  
Vol 145 (855) ◽  
pp. 475-488 ◽  
Keyword(s):  
Dielectric Constant ◽  
Empirical Equation ◽  
Relative Viscosity ◽  
Absolute Temperature ◽  
Differential Method ◽  
Theoretical Equation ◽  
Electronic Charge ◽  
Accurate Data ◽  
Avogadro’S Number ◽  
Strong Electrolytes

Until quite recently no satisfactory equation had been obtained for the representation of the viscosity of dilute solutions of strong electrolytes. An empirical equation was recently proposed by Jones and Dole to fit the only accurate data then available. Their equation may be represented thus : η = 1 + A √ c + B c , η = relative viscosity of the solution c = concentration in moles per litre A and B are constants. Jones and Dole realized that the coefficient A is due to interionic forces and in a series of later publications Falkenhagen, Dole and Vernon have deduced a theoretical equation giving values of A in terms of well-known physical constants. Their complete equation may be written η = 1 + ε √N v 1 z 1 /30η 0 √1000D k T ( z 1 + z 2 ) 4 π × [¼ μ 1 z 2 + μ 2 z 1 / μ 1 μ 2 - z 1 z 2 (μ 1 - μ 2 ) 2 /μ 1 μ 2 (√μ 1 z 1 + μ 2 z 2 + √(μ 1 + μ 2 ) ( z 1 + z 2 ) ) 2 ]√ c , where N = Avogadro's number v 1 , v 2 = numbers of ions z 1 , z 2 = valencies of ions μ 1 , μ 2 = absolute mobilities of ions D = dielectric constant of solvent k = Boltzmann's constant ε = electronic charge η 0 = viscosity of solvent T = absolute temperature.

Towards a Landscape Ethics

2020 ◽  
pp. 10-19
Author(s):  
Adriana Veríssimo Serrão
Keyword(s):  
Environmental Ethics ◽  
Global Environment ◽  
Theoretical Treatment ◽  
Ethical Dimension ◽  
Deep Roots ◽  
Wide Range ◽  
Levels Of Reality

The author seeks in this chapter to contribute to the deepening of the philosophy of landscape, an area of philosophy still in constitution, paying special attention to the ethical dimension. If the ethics of nature have deep roots in the great systems of idealism and romanticism, and if environmental ethics was most recently formed in the 1980s, offering solutions to the crisis of nature, a landscape-specific ethic did not merit still a sufficiently distinctive theoretical treatment. Some previous notes favor the need for this differentiation. Landscape, as it encompasses a wide range of intersections and interrelationships between various levels of reality—from natural to intervened or highly artificial landscapes—cannot be analytically extracted from nature. Landscape, as a differentiating concept, multiplied by unlimited world configurations, cannot be extracted from the (global) environment because, since each landscape is an individuality, its existence is always local.

scholarly journals Haemorheology in dilute, semi-dilute and dense suspensions of red blood cells

2019 ◽  
Vol 872 ◽  
pp. 818-848 ◽  
Author(s):  
Naoki Takeishi ◽  
Marco E. Rosti ◽  
Yohsuke Imai ◽  
Shigeo Wada ◽  
Luca Brandt
Keyword(s):  
Red Blood Cells ◽  
Intrinsic Viscosity ◽  
Blood Cells ◽  
Volume Fraction ◽  
Relative Viscosity ◽  
Shear Plane ◽  
Constitutive Law ◽  
Stable Mode ◽  
Volume Fractions ◽  
Wide Range

We present a numerical analysis of the rheology of a suspension of red blood cells (RBCs) in a wall-bounded shear flow. The flow is assumed as almost inertialess. The suspension of RBCs, modelled as biconcave capsules whose membrane follows the Skalak constitutive law, is simulated for a wide range of viscosity ratios between the cytoplasm and plasma,$\unicode[STIX]{x1D706}=0.1$–10, for volume fractions up to$\unicode[STIX]{x1D719}=0.41$and for different capillary numbers ($Ca$). Our numerical results show that an RBC at low$Ca$tends to orient to the shear plane and exhibits so-called rolling motion, a stable mode with higher intrinsic viscosity than the so-called tumbling motion. As$Ca$increases, the mode shifts from the rolling to the swinging motion. Hydrodynamic interactions (higher volume fraction) also allow RBCs to exhibit tumbling or swinging motions resulting in a drop of the intrinsic viscosity for dilute and semi-dilute suspensions. Because of this mode change, conventional ways of modelling the relative viscosity as a polynomial function of$\unicode[STIX]{x1D719}$cannot be simply applied in suspensions of RBCs at low volume fractions. The relative viscosity for high volume fractions, however, can be well described as a function of an effective volume fraction, defined by the volume of spheres of radius equal to the semi-middle axis of a deformed RBC. We find that the relative viscosity successfully collapses on a single nonlinear curve independently of$\unicode[STIX]{x1D706}$except for the case with$Ca\geqslant 0.4$, where the fit works only in the case of low/moderate volume fraction, and fails in the case of a fully dense suspension.

scholarly journals Operator Product Expansion, Heavy Quarks, QCD Duality and Its Violations

1997 ◽  
Vol 12 (11) ◽  
pp. 2075-2133 ◽  
Author(s):  
B. Chibisov ◽  
R. D. Dikeman ◽  
M. Shifman ◽  
N. G. Uraltsev
Keyword(s):  
Operator Product Expansion ◽  
Background Field ◽  
Decay Rates ◽  
Operator Product ◽  
Theoretical Treatment ◽  
Heavy Flavor ◽  
Wide Range ◽  
Euclidean Domain ◽  
Inclusive Processes ◽  
Hadron Duality

The quark(gluon)–hadron duality constitutes a basis for the theoretical treatment of a wide range of inclusive processes — from hadronic τ decays and Re+e- to semileptonic and nonleptonic decay rates of heavy flavor hadrons. A theoretical analysis of these processes is carried out by using the operator product expansion in the Euclidean domain, with subsequent analytic continuation to the Minkowski domain. We formulate the notion of the quark(gluon)–hadron duality in quantitative terms, then classify various contributions leading to violations of duality. A prominent role in the violations of duality seems to belong to the so-called exponential terms which, conceptually, may represent the (truncated) tail of the power series. A qualitative model, relying on an instanton background field, is developed, allowing one to get an estimate of the exponential terms. We then discuss a number of applications, mostly from heavy quark physics.

scholarly journals Note on the Standard of Relative Viscosity, and on “Negative Viscosity.”

1906 ◽  
Vol 25 (1) ◽  
pp. 227-230 ◽  
Author(s):  
W. W. Taylor
Keyword(s):  
Capillary Tube ◽  
Relative Viscosity ◽  
Absolute Viscosity ◽  
Flow Through ◽  
The Absolute ◽  
Negative Viscosity ◽  
Image Position

The absolute viscosity calculated from the formula(where p = the pressure, t the time, r the radius, l the length of capillary, and v the volume of liquid), which connects the viscosity of a liquid with the rate of flow through a long capillary tube, is not often made use of, mainly on account of the difficulty of accurately determining some of the constants (r in particular).

Oxy-Fuel Combustor Injector

2021 ◽  
Author(s):  
Shahrokh Etemad ◽  
Benjamin D. Baird ◽  
Sandeep Alavandi
Keyword(s):  
Natural Gas ◽  
Atmospheric Pressure ◽  
Stable Operation ◽  
Low Oxygen ◽  
High Dilution ◽  
Test Conditions ◽  
Wide Range ◽  
Cycle Efficiency ◽  
Oxygen Fuel ◽  
Validation Testing

Abstract Oxygen-fuel-diluent mixing is important for oxy-combustion as it impacts emissions, efficiency (oxygen slippage) and pattern factor. In this work, rapid mixing validation testing was conducted. Combustion testing was performed with natural gas and syngas from atmospheric pressure (1 atm.) to high pressure (10 atm.) to demonstrate stable operation. Oxy-natural gas testing demonstrated stable operation and low CO emissions over a wide range of test conditions. Syngas testing showed low CO emissions and a wider operability range with high dilution/low oxygen levels. Complete oxygen burnout was accomplished, indicating no oxygen slippage occurred at stoichiometric conditions and hence improved cycle efficiency.

High-Dilution Diffusion of K + , Rb + , Cs + , and Tl + in the Molten System (Li-K)NOs Studied by Wave-Front-Shearing Interferometry

1979 ◽  
Vol 34 (4) ◽  
pp. 504-509 ◽  
Author(s):  
Osamu Odawara ◽  
Isao Okada ◽  
Kazutaka Kawamura
Keyword(s):  
Diffusion Coefficient ◽  
Wave Front ◽  
Diffusion Coefficients ◽  
Free Space ◽  
Experimental Error ◽  
Positive Deviation ◽  
High Dilution ◽  
Ionic Radii ◽  
Shearing Interferometry ◽  
Wide Range

The high-dilution diffusion coefficients of K+, Rb+, Cs+, and Tl+ in molten LiNO3-KNO3 mixtures are measured over a wide range of temperatures and concentrations by means of wavefront- shearing interferometry. A slightly positive deviation from linearity is found for the concentration dependence of the diffusion coefficient of K+ , Rb+, and Tl+, while no deviation is found for Cs+ within the experimental error. This is qualitatively discussed from the viewpoint of the ionic radii, the free space in the solvent, and the interaction between the diffusing and the surrounding ions

Surface Temperatures Generated With Ceramic Materials in Oscillating/Fretting Contact

1994 ◽  
Vol 116 (2) ◽  
pp. 260-267 ◽  
Author(s):  
B. L. Weick ◽  
M. J. Furey ◽  
B. Vick
Keyword(s):  
Surface Temperature ◽  
Tungsten Carbide ◽  
Heat Generation ◽  
Tribological Behavior ◽  
Ceramic Materials ◽  
Frictional Heat ◽  
Theoretical Treatment ◽  
Frictional Heat Generation ◽  
Surface Temperatures ◽  
Wide Range

This paper summarizes the results of a study of the tribological behavior of ceramic materials in unlubricated oscillating/fretting contact with particular emphasis on frictionally-generated surface temperatures. The study was carried out using an oscillating contact device coupled to an infrared microscope. The contact geometry consists of a stationary spherical specimen loaded against a thin sapphire optical flat driven by an electromagnetic shaker. With this system, measurements can be made of friction, wear, and surface temperature over a wide range of loads, frequencies, and vibration amplitudes. Four ceramic materials were investigated, namely zirconium oxide (zirconia), tungsten carbide, and two different forms of aluminum oxide (alumina and sapphire). The first important finding was that each material exhibited unique and characteristic tribological behavior. Instantaneous variations in friction and surface temperature occurring within a single cycle of oscillation (e.g., in less than 0.005 seconds) could readily be measured with this technique. By digitizing the surface temperature, friction, and velocity signals, comparisons are made in the time and frequency domains. Frequency content correlations are determined using Fourier transform techniques. In addition, instantaneous frictional heat generation rates are calculated using the digitized friction and velocity data. Based on a series of experiments at constant oscillation frequency and amplitude, a correlation appears to exist between wear and surface temperature for the ceramics studied. Sapphire-on-sapphire and zirconia-on-sapphire produced the highest wear and the highest surface temperature rises (ca. 130–140 K). Tungsten carbide-on-sapphire produced the lowest wear and lowest surface temperature rise, while alumina exhibited intermediate behavior. In all cases, the rate of frictional heat generation was relatively low. It may be that the rapid fluctuations in surface temperature under these conditions—with two major temperature peaks per cycle—could lead to a kind of thermal stress fatigue of the ceramics as a wear mechanism. The use of the IR microscope in the scanning mode, coupled with scanning electron microscopy of the wear scars and theoretical treatment of sub-divided areas, can shed light on the nature and distribution of real areas of contact.

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