bluuebunny/crossref_metadata_2025_split huggingface dataset:
Semiconductive Colloidal Suspensions with Non-Linear Properties
Authors: Hollmann Hans E. 
Published: April 2005

Semiconductive particles in a colloidal suspension, when subjected to an electric polarizing field, form semiconductive chains. Once the suspension is polarized, its conductivity increases with increasing fields because the forces of electrostatic attraction press the individual particles together, thus strengthening the transition contacts along the chains. Both effects result in an over-all electric non-linearity that is the subject of extensive investigation.
The non-linear characteristics of such colloidal resistors are oscillographed and described in relation to the polarizing field strength by means of simple formulas based on field coefficients of the first and second order.
In addition to a true rectification, resulting from the curved characteristics, a ``pseudo-rectification'' occurs which corresponds to an average pre-polarization by stronger alternating fields. The alternating forces of electrostatic attraction assure a high frequency response, so that non-linear Lissajous-figures and harmonics, up to radiofrequencies, are produced.
Behavior of Granulated Polymers under Pressure
Authors: Spencer R. S. , Gilmore G. D. , Wiley R. M. 
Published: April 2005

In such fabricating processes as extrusion and injection molding it is frequently necessary to force a granular polymer through a channel. Frictional forces between polymer and channel walls lead to a drop in pressure through the granular material. Simultaneously, the applied pressure causes a compaction of the granules.
Assuming that the granular mass has certain fluid-like properties, a simple theoretical expression for pressure transmission is derived. Comparison with data on saran powders and granular polystyrenes shows good agreement between theory and experiment. The effect of lubrication is shown also.
The compaction of granular polystyrene follows the same pattern as that observed in the earth's crust. The porosity decreases exponentially with increasing pressure. The ``compressibility coefficient'' for the porosity of granular polystyrene is comparable with that given for clays and shales.
The Effective Permeability of an Array of Thin Conducting Disks
Authors: Estrin Gerald 
Published: April 2005

A three-dimensional array of thin conducting disks has found special application as an artificial refracting medium at microwave frequencies. Treatment of these refractive properties at oblique incidence requires specification of the dielectric and permeability coefficients of the medium.
When an alternating magnetic field is parallel to the disk faces, the field is undisturbed and the relative permeability coefficient is unity. When the alternating magnetic field is normal to the disk faces, circulating currents are induced on them. The boundary value problem of determining the current distribution on a single perfectly conducting disk is carried out in detail for the case where the disk diameter is small compared to the wave-length. This current distribution is found to be representable by a magnetic dipole. If the disks in an array are far enough apart to neglect interaction, a simple summation of the dipole moments shows the array to have a diamagnetic susceptibility in the direction normal to the disk faces.
Combining this result with an expression for the dielectric coefficient, which was developed earlier by Kock, the constants of the anisotropic array are completely specified.
Conductivity of Liquid Selenium-200°–500°C
Authors: Henkels Herbert W. 
Published: April 2005

The conductivity of liquid selenium has been measured in the temperature range 200°–500°C. The resistivity was expressed by log10ρ=A+(B/T). Average values for different selenium lots and melts of A and B were −3.81 and 5850. The maximum deviations from the averages were 10 percent and 3.4 percent respectively. The resistivity was a function of temperature alone.
Various non-metal impurities Cl2, I2, P lowered the resistivities and produced different values of B in different temperature ranges. Mercury addition caused no change in either A or B although that metal greatly influences the resistance of solid hexagonal selenium. Melts doped with Cl2 or Br2, along with Hg exhibited behaviors different from those with single additions.
It was concluded that selenium is an ideal semiconductor in the range of measurement.
A Model of Hurricane Formation
Authors: Riehl Herbert 
Published: April 2005

At first, the description of the energy cycle of the mature tropical storm is amplified on the basis of recent upper air observations. Air particles passing through such a storm at first undergo isothermal expansion as they move toward a center. Then they ascend with release of condensation. At high levels they move outward and mix with the environment giving off heat to the surrounding colder air. Several requisites for maintenance of the observed temperature field are stated.
After a discussion of previous theories of hurricane formation the proposed model is described. The initial intensification of the wind field is brought about by mass divergence at high levels that imposes a pressure reduction on the surface layers. This divergence is the result of interaction between the large-scale disturbances of the upper air inside and outside the tropics. A solenoidal circulation is initiated that acts in the kinetic energy producing sense. But this circulation contains an internal mechanism for its own destruction and is maintained only under certain special conditions which are stated.
Investigation of Field Distribution in Symmetrical Electron Lens
Authors: Shah J. R. , Jacob L. 
Published: April 2005

High accuracy of measurement in the electrolytic tank can be achieved by a suitable ratio of impedance as between tank and measuring circuit. With this requirement fulfilled, the axial distribution of the symmetrical lens was explored and found to satisfy a relation Vz=V0+Ae−bz(2), where V0 is the potential of the outers with respect to the middle electrode, `z,' the distance from the center of the lens, while A and b are constants from any one geometry.
The effect of varying the separation between the elements was specially investigated. It was found that the maximum value of the gradient between electrodes increases as the separation between them increases, reaches a flat maximum between 0.8 and 0.4 D (D, bore diameter) and then decreases with further increase in spacing. This means that a decrease in separation produces a weaker field and an increased focal length.
The potential at the saddle point is very sensitive to changes in separation in the region up to about 0.5 D; it was also found to vary linearly with bore up to 3 D.
The relaxation method of field plotting was also applied to map the distribution; the results are compared with those given by the tank.
Studies in Newtonian Flow. II. The Dependence of the Viscosity of Liquids on Free-Space
Authors: Doolittle Arthur K. 
Published: April 2005

In this paper it is shown that the viscosity of the liquid normal paraffins can be accurately defined as a simple function of relative free-space except for values in the neighborhood of the freezing points of each compound. A novel method of extrapolating the specific volumes of this family of compounds to absolute zero is described which permits the calculation of reliable values of the relative free-space from density data.
An expression of the same form as the author's function, but in which temperature rather than free-space is the primary variable (the so-called Andrade equation), fails to reproduce the viscosity of n-heptadecane over the same range of temperatures within the limits of the known accuracy of the measurements.
Dosimetry of X-Rays and Gamma-Rays by Radiophotoluminescence
Authors: Schulman James H. , Ginther Robert J. , Klick Clifford C. , Alger Raymond S. , Levy Robert A. 
Published: April 2005

The effects of high energy radiation on the luminescence properties of solids are surveyed. Of the four effects considered—radiophotoluminescence, radiophotostimulation, radiothermoluminescence, and the ``killing'' of luminescence by x-rays or gamma-rays—the first effect is shown to have advantages in principle over the others as a basis for dosimetry.
The absorption, excitation, emission, sensitivity, energy dependence, and stability characteristics of a radiophotoluminescent Ag-activated phosphate glass are described. It is shown that dosage measurements can be made with this material, employing a simple fluorophotometer, from 10 roentgens to a few thousand roentgens of gamma-rays. By proper shielding, such a dosimeter element can be made reasonably independent of energy. The dosage indication obtained is quite stable with time and is not seriously affected by exposure of the glass to visible or ultraviolet light or to temperatures in the range of −70° to +100°C. Because of its sensitivity range and its stability over a wide range of ambient conditions, the dosimeter appears to be particularly suited for monitoring personnel that may be exposed to rather high doses of gamma-rays, such as may be encountered in A-bomb explosions.
Some Measurements of Thermal Transpiration
Authors: Liang S. Chu 
Published: April 2005

Measurements have been made of the pressure ratio, R, due to thermal transpiration in hydrogen, helium, argon, and nitrogen between a warm temperature of 297°K and cold temperatures of 77.3 or 195°K. It is found that R depends on X, the product of the pressure and tube diameter according to the empirical relation, R=P1/P2=(AX2+BX+Rm)/(AX2+BX+1), where A and B are constants which depend on the gas and on the warm and cold temperatures, and Rm=(T1/T2)½. The R against P2, and threfore X, curves for different gases are found to be related by a ``pressure shifting factor'' f.
The use of these results to correct measurements of adsorption equilibrium and vapor pressures at low pressures and low temperatures is discussed.
Vapor pressures at 77.3°±0.5°K corrected for the thermomolecular pressure effect have been measured for krypton and xenon: Krypton1.754±0.002 mm;Xenon1.93 ±0.01×10−3 mm.
Periodic Statistical Distortion of Unidirectionally Ordered Diffractors, with Application to Collagen
Authors: Bear Richard S. , Bolduan Orvil E. A. 
Published: April 2005

The diffraction expected of distorted, one-dimensionally ordered cylinders (fibrils) is considered quantitatively. The distortion involved is statistically of cylindrical symmetry about any point in the fibril, and periodic along the fibril axis. An important case is that of the ``mixed perfect and imperfect fibril,'' in which, at some axial levels, distortion is absent, and at others it is appreciable. For such systems it is shown that the reciprocal-space disk corresponding to a given diffraction layer line may be regarded as composed of three sub-disks: one of perfection, whose central intensity is maximal and whose diameter is small and independent of layer-line index; another of longitudinal or axial imperfection, whose central intensity is also maximal; and a third, related to radial imperfection, whose intensity is noncentrally maximal. Both types of imperfection sub-disk expand linearly in diameter with increase in index.
It is demonstrated briefly that certain dry collagen specimens exhibit small-angle diffraction in which the characteristics of the three types of sub-disk are apparent.
Physical Entropy and Information. II
Authors: Brillouin L. 
Published: April 2005

The laws of statistical thermodynamics are used for the definition of entropy, and it is shown that the definition of information can be reduced to a problem of Fermi-Dirac statistics or to a generalized Fermi statistics. With these definitions, the entropy of a certain message can be defined, and the information contained in the message can be directly connected with the decrease of entropy in the system.
This definition leads directly to the formulas proposed by C. E. Shannon for the measure of information, and shows that Shannon's ``entropy of information'' corresponds to an equal amount of negative entropy in the physical system. The physical background of the whole method is discussed and found in agreement with previous discussions.
High Temperature Structure and Thermal Expansion of Some Metals as Determined by X-Ray Diffraction Data. I. Platinum, Tantalum, Niobium, and Molybdenum
Authors: Edwards James W. , Speiser Rudolph , Johnston Herrick L. 
Published: April 2005

The crystal structure and thermal expansion of platinum, tantalum, niobium, and molybdenum have been determined between 1100° and 2500°K. These metals were found to undergo a uniform thermal expansion over the temperature range of this investigation and to undergo no structural change. The permanent elongation of tantalum wires, produced by annealing at temperatures between 2473° and 2773°K, appears to be caused by reorientation of crystal grains in the specimen and to preferred direction of crystal growth during annealing, rather than to a change in crystal structure.
Quadratic equations have been developed for the thermal expansion of platinum, tantalum, niobium, and molybdenum. These equations are represented, respectively, by Δa0/a0=7.543×10−6(T−291)+2.362×10−9(T−291)2,Δa0/a0=6.080×10−6(T−291)+7.50×10−10(T−291)2,Δa0/a0=7.591×10−6(T−291)+6.96×10−10(T−291)2, and Δa0/a0=0.987×10−3+2.40×10−6(T−273)+2.20×10−9(T−273)2.
Values of the expansion coefficient α were computed for each of the metals by differentiating the above equations. Our values were compared with those obtained from the Grueneisen theory and indicate that the theory provides a reasonably satisfactory means of extrapolating thermal expansion data obtained at low and moderate temperatures.
Surface-Wave Propagation Over a Coated Plane Conductor
Authors: Attwood Stephen S. 
Published: April 2005

A TM-type wave is assumed propagated parallel to the surface of a plane conductor coated with a thin layer of dielectric. This wave is similar to the wave propagated over a dielectric-coated wire of circular cross section, discussed by Dr. Goubau in the references. Analysis of the cylindrical type wave requires the use of Hankel functions, while the wave over a plane surface may be described by simpler functions, namely, trigonometric functions in the dielectric layer and real exponential functions in the adjacent air region. The calculations thus are considerably simplified and the wave properties more readily observed.
Basic equations are developed for both dielectric layer and air regions, which indicate a criss-cross or multiply reflected wave in the dielectric and a unidirectional wave in the air. Equations are developed also for the electric flux line shapes, power propagated over the cross section, concentration of power flow in neighborhood of the film, attenuation due to conductor wall loss and dielectric film loss. Numerical calculations are given for five film thicknesses varying from 0.0001 to 0.01 meter and for five frequencies ranging from 3×108 to 3×1010 cycles per second.
Some Quantitative Data Bearing on the Scabbing of Metals under Explosive Attack
Authors: Rinehart John S. 
Published: April 2005

Fracturing, or scabbing, of a material near a free surface as the result of a transient compressional stress wave of high intensity impinging on that surface has been observed for many years; however, little quantitative data that relate the fracture to the nature of the stress wave and the physical properties of the material seem to exist. The phenomenon has been investigated for five metals, 1020 steel, 4130 steel, 24S-T4 aluminum alloy, brass, and copper, by using an explosive charge to induce a high intensity stress wave in the metal. The distribution of pressure within the wave was determined by a modified Hopkinson-bar type of experiment.
Scabbing has been found to be governed principally by the spatial distribution of pressure within the wave and a critical normal fracture stress σc that is characteristic of the material and perhaps the state of stress. Numerical values of σc were obtained for each of the five metals.
On Shock-Wave Phenomena: Waterlike Substances
Authors: Seeger R. J. , Polachek H. 
Published: April 2005

The properties of shock waves in waterlike substances are investigated in detail. A waterlike substance is defined as one for which the intrinsic energy is separable into a sum of two terms, one of which is a function of density only and the second a function of specific entropy. It is known that many substances, including water, behave in this fashion within a large range of pressure variation.
The paper consists of six sections. Section I contains some introductory material. Section II consists of a derivation of the basic equations that govern the propagation of plane shock waves in a waterlike substance. Section III is an analysis of one-dimensional interaction of shock waves, rarefaction waves, and contact discontinuities in a medium of this type. It is shown that a number of intrinsic differences exist between the behavior of shock waves in waterlike substances and their behavior in ideal gases.
In Section IV, one-dimensional interaction of shock waves in arbitrary fluids is discussed. Section V presents the theory of regular reflection of shock waves in waterlike substances; while Section VI presents the theory of triple-shock intersections. In both instances essential differences between the behavior of shock waves in waterlike substances and ideal gases are noted. The text is supplemented by numerous tables and charts.
Behavior of the Resistance Ignitor in Mercury
Authors: Rigrod W. W. 
Published: April 2005

An empiric expression has been derived for the probability of arc striking per unit time, per unit length of contact perimeter, for a resistance ignitor in a mercury-pool tube: p′=k(E−E0)3/ρ2, where k and E0 are constants, E is the ``useful'' electric field strength near the mercury surface, and ρ the resistivity of ignitor material at the junction with the mercury.
From the foregoing, a formula has been established for the probability of ignition per unit time, for the entire ignitor, in terms of the applied voltage v and ignitor ``firing resistance'' R. With this formula, whose two arbitrary constants can be determined by two sets of measurements, the firing voltage of any ignitor can be predicted under a wide variety of circuit conditions, provided R remains unchanged under these conditions.
The probability formula was found to be consistent with a modification of a theory advanced by L. Tonks, whereby mercury surface distortion and rupture permit field emission at field strengths less than those effective for smooth surfaces. The modification attributes the reduction in ignitor firing voltage by ignitor current to its extremely localized ohmic heating of the mercury. This heating reduces the surface tension and roughens the mercury surface, thereby accelerating the process of surface rupture by the electric field.
On the Nonspecular Reflection of Electromagnetic Waves
Authors: Twersky Victor 
Published: April 2005

The nonspecular reflection of plane electromagnetic waves of arbitrary polarization by certain perfectly conducting surfaces composed of either semicylindrical or hemispherical bosses on an infinite plane is analyzed. Solutions for the problem of the single boss on an infinite plane and a plane wave at an arbitrary angle of incidence are given and extended subject to the single-scattering hypothesis to obtain the far field solutions for certain small finite patterned distributions and both small finite and infinite uniform random distributions of bosses small compared with the wavelength. The results for the various cases are then compared in the plane of incidence and similarities between the analogous expressions for the distributions of semi-cylinders and hemispheres are noted. Expressions are obtained for the ratios of the components of the reflected intensity and radial energy flux polarized parallel and perpendicular to the plane of incidence as well as for the total intensity and radial energy flux for the case where the incident wave is unpolarized. It is found that for certain values of the parameters the reflected radiation may consist only of either the specular or the scattered contributions, while for other values one of the scattered contributions, either the parallel or perpendicular component, may vanish. The results also indicate the occurrence of an extremum in the reflected radiation in the vicinity of the specular angle of reflection, which for certain ranges of the parameters for the small finite distributions may be a minimum rather than a maximum. For these cases there is also some critical angle of incidence (not necessarily π/2 or grazing incidence) for which the reflection at the specular angle is completely specular.
The analogous distributions of cylinders and spheres are also considered.
The Motion and Precipitation of Suspensoids in Divergent Electric Fields
Authors: Pohl Herbert A. 
Published: April 2005

The motion of suspensoid particles relative to that of the solvent resulting from polarization forces produced by an inhomogeneous electric field is defined as ``dielectrophoresis.'' It is analogous to the related phenomenon of electrophoresis, in which motion of suspensoid particles is produced by the action of an electrostatic field on the charged particles.
From a consideration of theoretical calculations and from experimental observations it is concluded that the phenomena of ``dielectrophoresis'' and ``dielectro-precipitation'' can be observed under rather ideal conditions, though it is ordinarily often difficult to do so because of the presence of the more easily produced electrophoresis or ion-type migration of charged particles.
The usefulness of dielectrophoresis (and/or electrophoresis) for removing suspended solid particles from polymer solutions during analysis is described.
The Production and Stability of Converging Shock Waves
Authors: Perry Robert W. , Kantrowitz Arthur 
Published: April 2005

Converging shock waves offer interesting possibilities of attaining very high temperatures and pressures. A theoretical treatment by G. Guderley which we have confirmed and extended by the method of characteristics indicated that the strength of a strong converging cylindrical or spherical shock varies inversely with a power (0.396 for γ=1.4) of the surface area of the wave, thus becoming very great close to the center of convergence. The experimental production of high temperatures and pressures by means of these converging shocks depends on their ``stability'' of form. A converging wave is said to be stable if it approaches perfect cylindrical or spherical shape, thus damping out random disturbances as it propagates. The experimental work of L. G. Smith on Mach reflection is applied to show that these converging waves are stable for the shock range (M≤2.4) covered by his experiments. Smith's work and the theoretical work of Lighthill indicate that the stability decreases greatly at high Mach numbers.
The simplest experimental method of achieving a cylindrical converging shock is by the use of a shock tube with a converging channel. This, however, results in the hottest region of the gas being in close thermal contact with the cold walls. An axially symmetric shock tube has been designed and constructed which produces a complete converging cylindrical shock rather than just a sector and in which the region of convergence is comparatively well isolated thermally from the walls. It has been found possible to converge a moderate strength shock wave (M=1.7) sufficiently to produce considerable luminosity at the center of convergence. Schlieren photographs are presented showing various phases of the formation and stability of these converging waves.