scholarly journals VII. On the viscosity of gases at high exhaustions

1881 ◽  
Vol 172 ◽  
pp. 387-446 ◽  
Keyword(s):  
Internal Friction ◽  
Plane Surface ◽  
Tangential Force ◽  
The Other ◽  
British Association ◽  
Mean Velocity ◽  
Total Action ◽  
The Mean ◽  
The One

635. By the viscosity or internal friction of a gas, is meant the resistance it offers to the gliding of one portion over another. In a paper read before the British Association in 1859, Maxwell† gives the following explanation of the internal friction of gases:— “Particles having the mean velocity of translation belonging to one layer of the gas, pass out of it into another layer having a different velocity of translation, and by striking against the particles of the second layer exert upon it a tangential force which constitutes the internal friction of the gas. The whole friction between two portions of gas separated by a plane surface, depends upon the total action between all the layers on the one side of that surface upon all the layers on the other side.”

Toroidal plasma configuration with anisotropic pressure

1987 ◽  
Vol 38 (2) ◽  
pp. 209-222 ◽  
Author(s):  
Hussain M. Rizk
Keyword(s):  
General Expression ◽  
Magnetic Surface ◽  
Anisotropic Pressure ◽  
Mean Velocity ◽  
Magnetohydrodynamic Equation ◽  
Toroidal Plasma ◽  
Hydrodynamic Calculations ◽  
The Mean ◽  
The One ◽  
Plasma Configuration

The relation between various surface quantities required in hydrodynamic calculations, and the relation between the parallel and perpendicular currents in an arbitrary magnetic toroidal plasma configuration with scalar pressure, are generalized to the case of anisotropic pressure. Magnetic co-ordinates for hydrodynamic equilibria in this configuration are defined. A general expression for the mean velocity of diffusion through a magnetic surface, on the basis of the one-fluid magnetohydrodynamic equation with anisotropic pressure, is derived.

On Turbulent Flow Between Parallel Plates

1953 ◽  
Vol 20 (1) ◽  
pp. 109-114
Author(s):  
S. I. Pai
Keyword(s):  
Turbulent Flow ◽  
Velocity Distribution ◽  
Poiseuille Flow ◽  
The Other ◽  
Turbulent Velocity ◽  
Parallel Plates ◽  
Mean Velocity ◽  
Reynolds Equations ◽  
Mean Pressure ◽  
The Mean

Abstract The Reynolds equations of motion of turbulent flow of incompressible fluid have been studied for turbulent flow between parallel plates. The number of these equations is finally reduced to two. One of these consists of mean velocity and correlation between transverse and longitudinal turbulent-velocity fluctuations u 1 ′ u 2 ′ ¯ only. The other consists of the mean pressure and transverse turbulent-velocity intensity. Some conclusions about the mean pressure distribution and turbulent fluctuations are drawn. These equations are applied to two special cases: One is Poiseuille flow in which both plates are at rest and the other is Couette flow in which one plate is at rest and the other is moving with constant velocity. The mean velocity distribution and the correlation u 1 ′ u 2 ′ ¯ can be expressed in a form of polynomial of the co-ordinate in the direction perpendicular to the plates, with the ratio of shearing stress on the plate to that of the corresponding laminar flow of the same maximum velocity as a parameter. These expressions hold true all the way across the plates, i.e., both the turbulent region and viscous layer including the laminar sublayer. These expressions for Poiseuille flow have been checked with experimental data of Laufer fairly well. It also shows that the logarithmic mean velocity distribution is not a rigorous solution of Reynolds equations.

The Effect of Waking Suggestion on Post-Hypnotic Amnesia

1981 ◽  
Vol 11 (1) ◽  
pp. 44-46 ◽  
Author(s):  
D.P. Fourie
Keyword(s):  
Point Of View ◽  
The Other ◽  
Hypnotic Susceptibility ◽  
The Subject ◽  
The Mean ◽  
The Difference ◽  
The One ◽  
The Relationship ◽  
Female Subjects

It is increasingly realized that hypnosis may be seen from an interpersonal point of view, meaning that it forms part of the relationship between the hypnotist and the subject. From this premise it follows that what goes on in the relationship prior to hypnosis probably has an influence on the hypnosis. Certain of these prior occurences can then be seen as waking suggestionns (however implicitly given) that the subject should behave in a certain way with regard to the subsequent hypnosis. A study was conducted to test the hypothesis that waking suggestions regarding post-hypnotic amnesia are effective. Eighteen female subjects were randomly divided into two groups. The groups listened to a tape-recorded talk on hypnosis in which for the one group amnesia for the subsequent hypnotic experience and for the other group no such amnesia was suggested. Thereafter the Stanford Hypnotic Susceptibility Scale was administered to all subjects. Only the interrogation part of the amnesia item of the scale was administered. The subjects to whom post-hypnotic amnesia was suggested tended to score lower on the amnesia item than the other subjects, as was expected, but the difference between the mean amnesia scores of the two groups was not significant.

Experimental Study on Near-Wall Bubble Clustering Behaviors in Bubbly Channel Flow (Keynote)

2003 ◽  
Author(s):  
Soo-Hyun So ◽  
Shu Takagi ◽  
Akiko Fujiwara ◽  
Yoichiro Matsumoto
Keyword(s):  
Liquid Phase ◽  
Bubble Size ◽  
The Other ◽  
Image Processing Technique ◽  
Cluster Center ◽  
Turbulence Structure ◽  
Mean Velocity ◽  
Bubble Cluster ◽  
The Mean ◽  
Near Wall

The turbulence properties of gas-liquid bubbly flows and the near-wall bubble clustering behaviors are investigated for upward flow in a rectangular channel. Bubble size distributions are well-controlled and the flow with mono-dispersed 1mm-diameter and that with 1–4mm diameter bubbles are compared. Bubble size, turbulent properties of liquid phase and the bubble cluster motion were measured using image-processing technique, Laser Doppler Velocimetry (LDV) and Particle Image Velocimetry (PIV), respectively. To create the mono-dispersed small bubbles by the bubble generator, being made of stainless steel pipes, a small amount of surfactant (20ppm of 3-pentanol) was added into the flow. In this study, experiments with three different bulk Reynolds numbers (1350, 4100, 8200) were conducted with void fractions less than 0.6% in the fluid with/without the surfactant. In all cases with surfactant, there was a very high accumulation of bubbles near the wall. The local void fraction has a wall-peak distribution and the horizontal bubble clusters are formed near the wall. As a result, the local mean velocity of the liquid phase becomes larger near the wall due to the driving force of buoyant bubbles and the stream-wise turbulent intensity in the vicinity of the wall was enhanced. On the other hand, the turbulent fluctuations and Reynolds stress are remarkably suppressed in the other region. At the Reynolds number of 8200, the bubble cluster was investigated. Experimental observation showed that the bubble cluster changes its shape in time and that the shape change is caused by the difference of the rising velocity between the cluster center and the both ends. The clusters accelerated the mean streamwise velocity near the wall, thus the mean velocity profile of the liquid phase becomes flattened. It is suggested that the highly concentrated bubbles in the vicinity of the wall disturb the transport of turbulence energy produced in the wall shear layer toward the center of channel. Moreover, in the middle of channel, the turbulence structure is governed by pseudo-turbulence induced by present bubbles.

On the capture of interstellar matter by stars

1940 ◽  
Vol 36 (3) ◽  
pp. 314-322 ◽  
Author(s):  
R. d'E. Atkinson
Keyword(s):  
Radial Velocity ◽  
The Other ◽  
Interstellar Matter ◽  
Centre Of Gravity ◽  
Compelling Reason ◽  
Other Hand ◽  
The Mean ◽  
The One ◽  
The Individual ◽  
Capture Radius

The derivation given by Hoyle and Lyttleton for an accretion formula proposed by them is examined. A number of arguments against its validity are put forward, especially that on the one hand their capture radius depends on the theorem that if the velocity of certain masses of gas after collision is less than the velocity of escape at the point, they will not in fact escape, while on the other hand it is clear (and is now admitted) that the gas cannot in fact move with this velocity at all. It is also shown that since, ex hypothesi, the individual molecules will all, on the average, retain their hyperbolic velocities, there is not the compelling reason for their capture that there appeared to be in Hoyle and Lyttleton's argument, where only the mean radial velocity of the centre of gravity of the mass was considered. Further, it seems improbable that the temperature of the interstellar matter can be low enough for the initial assumptions of their theory to hold.

Struktur von Schmelzen aus dem System Wismut-Antimon mittels Neutronenbeugung

1976 ◽  
Vol 31 (1) ◽  
pp. 90-101 ◽  
Author(s):  
Peter Lamparter ◽  
Siegfried Steeb ◽  
Walter Knoll
Keyword(s):  
Neutron Diffraction ◽  
Coordination Number ◽  
Covalent Binding ◽  
The Other ◽  
Nearest Neighbour ◽  
Neighbour Distance ◽  
The Mean ◽  
The One ◽  
Subsidiary Maxima ◽  
Versus Concentration

Neutron diffraction work (λ = 0.695 Å) was done with molten Bi-Sb-alloys in the temperature range between 550 and 750 °C. Furthermore molten Bi was investigated at 300 °C. The interference functions show subsidiary maxima especially for alloys with higher Sb-concentrations. Evaluation yields, that the melts contain two different kinds of structure:a) The one kind shows coordination number 9 and a statistical distribution of the atoms of two components. This kind is more inetal-like.b) The other kind shows coordination number 3, consists of non-centered tetrahedra with smaller nearest neighbour distance. It shows covalent binding.In molten Sb the nearest neighbour distance amounts up to 3.16 - 3.19 Å for theo ne kind and up to 2.64 -2.78 Å fort he other kind, which yields an mean distance of 2.99 Å, which was observed. The dependence of the concentration of the statistical kind of meld, of the (Sb)4-, and the (Bi)4-kind from the concentration of the whole melt is given.By the model described the run of the measured mean coordination number and the mean distance versus concentration can be well explained.

Asymptotic independence of counts in isotropic planar point processes of phase-type

2000 ◽  
Vol 32 (2) ◽  
pp. 363-375
Author(s):  
Marie-Ange Remiche
Keyword(s):  
Poisson Process ◽  
Arbitrary Shape ◽  
Point Processes ◽  
The Other ◽  
Asymptotic Independence ◽  
Planar Point ◽  
Phase Type ◽  
Disjoint Sets ◽  
The Mean ◽  
The One

The isotropic planar point processes of phase-type are natural generalizations of the Poisson process on the plane. On the one hand, those processes are isotropic and stationary for the mean count, as in the case of the Poisson process. On the other hand, they exhibit dependence of counts in disjoint sets. In a recent paper, we have proved that the number of points in a square window has a Poisson distribution asymptotically as the window is located far away from the origin of the process. We extend our work to the case of a window of arbitrary shape.

scholarly journals VI. The specific heats of metals and the relation of specific heat to atomic weight.—Part III

1904 ◽  
Vol 203 (359-371) ◽  
pp. 139-149 ◽  
Keyword(s):  
Specific Heat ◽  
Atomic Weight ◽  
The Other ◽  
Influence Of Temperature ◽  
Specific Heats ◽  
Weight Part ◽  
Chemical Combination ◽  
Influence Of Temperature On ◽  
The Mean ◽  
The One

The law of Neumann assumes that when an atom enters into chemical combination it retains the same capacity for heat as when in the uncombined or elemental state. This generalisation is, however, based on the values observed for the mean specific heats of elements and their compounds between 0° and 100° C. Attention was directed in Part II. of this investigation to the great differences found in the influence of temperature on the specific heats of various metals, such as aluminium on the one hand, and silver or platinum on the other. The experiments now about to be described were undertaken with the object of ascertaining to what extent these differences persist in the compounds of such elements.

scholarly journals Tables of the variation, through a cycle of nine years, of the mean height of the barometer, mean temperature, and depth of rain, as connected with the prevailing winds, influenced in their direction by the occurrence of the lunar apsides, with some concluding observations on the result

1843 ◽  
Vol 4 ◽  
pp. 226-227
Keyword(s):  
The Other ◽  
Mean Temperature ◽  
The Mean ◽  
The One

From the Tables here given, the author draws the following conclusions:— 1 The barometer is higher under the lunar apogee, than under the perigee; the mean height in the former case being 29·84517, and in the latter, 29·75542. 2. The mean temperature is lower under the apogee than under the perigee; that of the former being 48°·7126, and of the latter, 49°·0356. The mean of the whole year was 48°·7126. 3. The rain of the weeks following the apsis exceeds that under the perigee; but with two striking exceptions in the annual result of nine years, the one in the wettest, and the other in the driest year of the cycle.

scholarly journals Skin friction of the wind on the Earth's surface

1916 ◽  
Vol 92 (637) ◽  
pp. 196-199 ◽  
Keyword(s):  
Flat Plate ◽  
Skin Friction ◽  
Solid Surface ◽  
Unit Area ◽  
Tangential Force ◽  
Mean Velocity ◽  
Small Surface ◽  
The Mean ◽  
General Velocity ◽  
Very High

The mechanism by means of which momentum is transmitted to a solid surface, in order that it may exert a drag on a fluid flowing past it, is at present understood only very imperfectly. It seems certain, however, that the law of dynamical similarity is applicable to skin friction; if therefore it were possible to measure the tangential force exerted by the wind as it blows over a large tract of land, it should be equal to the skin friction on a similar small surface when subjected to the action of the very high wind which would correspond with the same value of l V/ v . In reducing the tract of land to a similar small flat plate, the trees and houses would be reduced to a mere roughness on the plate. It is to be expected therefore that, if the skin friction on unit area of the earth's surface be expressed in the form F = kp Q 2 s , (1) Q s being the wind velocity near the surface and p the density of air, the constant k will be the same as the constant which would be found in the laboratory by experimenting with a small, slightly roughened plate, if a sufficiently high value of l V/ v , could be obtained. It should be noticed, however, that the velocity which should be compared with is the velocity close to the solid surface and not the general velocity of the air in the case of a flat plate, or the mean velocity over a cross section in the case of flow in a pipe.

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