bluuebunny/crossref_metadata_2025 huggingface dataset:
Fatigue and Crystal Recovery in Aluminum
Authors: Smith Howard A.
Published: January 2005

The previous x-ray work on fatigue in metals is reviewed. Such work has been confined to copper, silver and steel. The present note reports on the results of an investigation of service fatigue fractures in high voltage transmission cables made of commercially pure aluminum. The crystals composing the shallow surface layer of the fractures were found to have recovered sufficiently from the microscopic distorsion due to cold drawing that individual monochromatic diffraction spots could be identified. Two possible contributing causes are suggested to explain this crystalline recovery.
Further Studies on the Relation Between Constitution and Association: Especially in Reference to Aromatic Compounds
Authors: Bingham Eugene C. , Geddes John A.
Published: January 2005

The fluidities of fifteen ortho, meta and para compounds have been measured at temperatures of 0°C to 100°C, except when the melting point of the compounds interfered with measurements at the lower temperatures. The specific volumes of 14 of these compounds have been measured at the same temperatures. From the atomic temperature constants of C, H, O, Cl, Br and N given by Bingham and Spooner, the associations of the compounds have been calculated, whenever possible, at fluidities of 50, 100 and 200 rhes. From these same constants, and that of F determined by the authors, the associations of 14 ortho, meta and para compounds run by Swarts have been calculated at equal fluidities. On the basis of the theory of protection, the associations of these 29 compounds and of 17 ortho, meta and para compounds studied previously have been correlated.

In the case of compounds containing two non-associating groups, (A) The fluidity-temperature curves of the meta and para compounds cross, the para compound having the higher temperature coefficient of fluidity. (B) At low temperatures, the ortho compound is the most associated, the para next, and the meta compound has the least association. (C) At high temperatures, the ortho compound is the most associated, the meta next, and the para has the least association.

In the case of aromatic compounds, containing one non-associating and one associating group, the differences will be less clearly marked, but: (A) In general, the ortho compound is the least associated, the meta next, and the para compound is most associated. (B) In the phenetidines, at low temperatures, the meta compound is more associated than the para compound, but, having a higher temperature coefficient of fluidity, its fluidity-temperature curve shows a tendency to cross that of para-phenetidine, and at high temperatures, the associations will run o<m<p. (C) Where the associating group is NO2, the associations of the three isomers are nearly equal, with that of the meta compound being slightly lower than the associations of the ortho and para compounds.

In the case of compounds containing two associating groups, according to the theory, the associations should run o<m<p. Time was not available to run any of these compounds, and there are no fluidity data on them in the literature since all are solids at ordinary temperatures. In general, however, the boiling points of these substances, which vary in the same order as the association, run o<m<p (Table V). Unfortunately, even these data are scanty.

It is shown that the theory of protection offers an explanation for the behavior noted above.
The Stress-Strain Relation in Textile Fibers
Authors: Steinberger R. L.
Published: January 2005

Stress-strain relations for eight common textile fibers are given (four rayons, silk, wool, cotton and ramie) under known humidity conditions. The method has two novel features: (1) In each experiment the section area was determined on the specific fiber under test, (2) the elongations were made in steps, with a relaxation interval of 30 seconds between stress observations, rather than at a constant rate which is the usual practice. The rayons exhibit an accurately linear initial curve from which Young's modulus can be determined, followed by a yield point and a long region of plastic flow. The curves for cotton and ramie are linear with no plastic yield in the range examined. In silk and wool there is no proportionality between stress and strain. Cellulose acetate exhibits the phenomena of ``cold working'' and marked increase of total and elastic energy with falling relative humidity. The application of Maxwell's relaxation equation is examined.
On the Theory of an N-Winding Transformer
Authors: Brown Lawrence E.
Published: January 2005

The problem of a transformer of n windings, each connected to a circuit containing a source of electromotive force, is treated. The assumptions are pure reactance windings, perfect couplings and linear loads. The equations for the current in any circuit, the open-circuit voltage across any winding, the short-circuit current in any winding, the impedance looking in at any winding, the voltage transformation ratios, the current transformation ratios and the impedance transformation ratios are given. The ideal n-winding transformer, which is a more restricted case, is also treated.
Methods for Calculating the Volumetric Composition of Fluid Mixtures
Authors: Ingberg S. H.
Published: January 2005

The mathematical treatment relating to mixture of fluids in a container maintained at constant pressure and volume is developed, assuming perfect and instantaneous diffusion, free efflux and no reaction between the components of the mixture. For comparison, the equations for mixture within a container from which no efflux takes place are given and also a treatment applicable to intermediate conditions. Specific applications are developed pertaining to conditions involving inert gas, such as carbon dioxide, flue gas or engine exhaust gas, released into an inclosure by automatic or manual means to extinguish fire, and to the subsequent ventilation of spaces thus deluged to reduce the toxic gas content and raise the oxygen content to limits making such spaces safe for entry.
Sorption on Cotton Fibers of Dyes with Varying Molecular Association in Solution
Authors: Clark George L. , Southard Julia
Published: January 2005

X-ray diffraction patterns of aqueous solutions of the oxazine dye, Nile blue sulfate, yield direct evidence of a varying molecular association as a function of concentration, which was previously indicated by Cohen's potentiometric and spectrophotometric data. Solutions of the order of millionth molar approach obedience to the laws of dilute solutions; in moderate concentrations of the order of 5×10−4 molar the dye molecules associate to micellar structures; and in concentrated solutions the association proceeds to the stage of precipitation. The largest change in the value of the identity spacing d corresponding to the inner edge of the principal diffraction halo is found to begin with about 10−4 molar solutions. The attempt is then made to measure pore sizes in cotton fibers from the relative absorbability of the dye from its solutions over such a range of molecular and aggregate dimensions. Nile blue sulfate and methylene blue solutions before and after addition of absorbent cotton were subjected to spectrophotometric analysis. Again it is indicated in the case of the former that there is a large increase in dye absorption by the cotton corresponding to the change with increasing dilution from micellar to molecular dimensions which are compatible with predominating cotton pore sizes.
The Absorption of Heat Rays by Fog
Authors: Hulburt E. O.
Published: January 2005

Measurements between two stations 0.4 km apart of the intensity of heat rays transmitted through fog showed that, although 7μ rays were slightly less absorbed by fog than visible light, their penetration into fog was too slight to be of practical interest. For a fog of visibility 0.6 km the distances to reduce the light to 10−2 were 910, 970, 980 and 1140 meters for wavelengths 0.6, 1, 3 and 7μ, respectively.
On the Theoretical Determination of Earth Resistance from Surface Potential Measurements
Authors: Stevenson A. F.
Published: January 2005

A general solution for the potential in the steady flow of current from a single point electrode when the conductivity is an arbitrary continuous function of position is given in the form of an infinite series, by using the method of successive approximations, and conditions for the validity of the solution discussed. The converse problem of determining the conductivity when the surface potential is known is then shown to lead to an integral equation, which has no unique solution. The problem can be made determinate, however, by restricting the functional form of the conductivity—in particular by supposing that it is a function of depth only—or by supposing that the electrode is movable, and that the surface potential is known for all positions of the electrode on some curve at the surface. It is shown how the integral equations can be formally solved by the method of successive approximations. For the special case where the conductivity is a function of depth only, the first approximation is worked out in detail, and an approximate method is given for solving the resulting integral equation for the conductivity. This method is critically discussed and compared with the more exact method of Slichter and Langer. A numerical example is worked out where the conductivity is known in advance, namely a special case of the three-layer earth. It is shown that the present method gives a rough indication of the true behavior of the conductivity, but that the Slichter-Langer method and the ``apparent resistivity'' method both fail completely for this case. It is suggested that in certain cases the present method might give a better result than that of Slichter and Langer.
The Creep of Wires at High Temperature
Authors: Richmond W. O.
Published: January 2005

This paper describes apparatus developed to make creep tests on wires at high temperatures in a vacuum, and the results of a series of creep tests on wires of an alloy known as Konal at temperatures of from 800 to 1000°C. It is shown that Ludwik's logarithmic law connecting rate of deformation and stress holds for higher creep rates and stresses, although it certainly does not hold for the lower creep rates and stresses. In the range of temperatures tested, it is found that a linear relation best expresses the variation of the logarithm of the minimum creep rate with temperature. The method used is suggested as being readily adaptable to the making of short time creep tests, for obtaining comparative creep data in a relatively short time on materials used at high temperatures.
Concerning the Effect of Strain and Rate of Strain on Tensile Tests at Normal and Elevated Temperatures
Authors: Beeuwkes R.
Published: January 2005

A few idealized cases of plastic flow have been analyzed in an attempt to show the influence of constant coefficients of work-hardening and pure viscosity on tests made at normal and elevated temperatures. Although it is true that the assumed linear expression might approximately fit cases of very low stresses and small strains, of the order of a percent or less, it cannot be used to explain test results in which annealing and chemical changes occur, as they often do in practice. It is believed, however, that the cases discussed do bring certain fundamental considerations into sharper definition than in the past. They indicate that more emphasis should be placed by experimenters on the changes in yield stress (in the hardness) that occur in materials even without stress under exposure to time and high temperature.
Concerning the Distribution of Stress in a Laterally Compressed Strip
Authors: MacGregor C. W.
Published: January 2005

Photoelastic tests are described in which the contact pressure distribution produced by laterally compressing a strip of Bakelite between rollers of the same material is approximately determined. Further, the shapes of the shear stress trajectories as predicted by the elastic theory for a cylinder compressed between two concentrated loads are compared with the shapes of the flow layers obtained by compression tests on mild steel cylinders. A fairly good agreement was obtained.
X-Ray Crystal Measurements of Nickel at High Temperatures
Authors: Jesse William P.
Published: January 2005

X-ray powder photographs have been made of an electrically heated nickel ribbon sealed into a thin-walled glass bulb. X-ray measurements extending from 450 to 1200°C showed no new high temperature crystal form of nickel. The thermal expansion of the face-centered cubic lattice, present throughout the range investigated, is in agreement with macroscopic thermal expansion data.
Propagation of Elastic Waves in Ice. Part I
Authors: Ewing Maurice , Crary A. P. , Thorne A. M.
Published: January 2005

Measurements of the velocity of sound vibrations in ice have been made in some detail both by direct and resonance methods. The velocity of longitudinal waves was measured directly on large bodies of ice. Blasting caps were used to create elastic disturbances and the time of travel was recorded by an electric seismograph placed at suitable distances. A plot of time against distance gives a remarkably straight line showing a velocity of 3410 m/sec. Laboratory measurements were made on long thin rods of ice which were excited by an oscillator and resonance frequencies measured both for longitudinal and torsional vibrations. The velocities for these vibrations are found to be 3163 m/sec. and 1913 m/sec., respectively. A formula is derived by which the velocity of longitudinal waves in a thin infinite plate can be found from these velocities. This formula gives a value of 3400 m/sec. which checks with that obtained directly by less than one percent. Various other elastic constants for ice are also deduced from these measurements. The values of Young's modulus and Poisson's ratio for ice are found to be 9.17×1010 dynes/cm2 and 0.365, respectively, in the range −5°C to −15°C.
Permeability Changes in Ferromagnetic Materials Heat Treated in Magnetic Fields
Authors: Kelsall G. A.
Published: January 2005

Very high maximum magnetic permeability has been obtained in certain ferromagnetic alloys by slowly cooling them in a magnetic field. In permalloy with 78.5 percent nickel it has thus been raised above 140,000 that is, to the same order as is obtainable by rapid cooling without an applied field. In perminvar with 45 percent nickel, 30 percent iron and 25 percent cobalt this magnetic heat treatment is also found to be effective. It is also shown that the maximum permeability is highest if the testing field is in the same direction as that of the field applied during cooling. In directions at right angles to this, the maximum permeability is decreased. The ratio of the two permeabilities in one instance was over 14 for permalloy, and in another instance nearly 70 for perminvar.
Space Charge Grid Tube with Variable Mu Grid
Authors: Dehlinger Walter
Published: January 2005

Solutions of the generalized equations of the variable Mu triode exp (pv)= ∫ v∞(v+z)kF(z)(dx/dz)dz(v+z0)n= ∫ vz0(v+z)kF(z)(dx/dz)dzfor dx/dz are given by means of the gamma-function. Here z is the reciprocal of the amplification constant, x is the axial distance along the grid, v is the ratio of grid to plate voltage and k is the space charge constant, usually 3/2. The constant n or p determines the shape of the plate current, grid voltage curve desired. The only restrictions for the values of n and k are n>k>0Π(n−k−1)≠∞.The solution of the integral equation of the space charge grid tube is reduced to that of the triode by a process of summation. Graphical methods are developed by means of which the distribution of grid pitches can be determined from the solution of the integral equation.
An Investigation of an Alternating-Current Method of Determining Critical Potentials
Authors: Hickman Roger W.
Published: January 2005

An investigation of an alternating-current bridge method of measuring critical potentials in a vapor has been made. The tube containing mercury vapor and of similar structure to that used in the experiments of Franck and Hertz was placed in one arm of an impedance bridge and so arranged that a small alternating voltage in series with a small direct retarding voltage existed between the accelerating grid and collecting plate. Measurements of the equivalent variational plate resistance and reactance were made as the steady accelerating voltage was varied. Plots of the variational resistance or reactance, or the bridge balancing resistance or capacitance as a function of the accelerating voltage, showed the typical irregularities found in the ordinary current-voltage plots to be enhanced. The positions of the irregularities were found to be independent of the frequency and dependent on the amplitude of the applied alternating voltage within the range investigated. Results indicated that the resolving power of the method varies inversely with the amplitude of applied alternating voltage. The effect of vapor pressure on the position and evolution of the irregularities was also studied.
Nonmetallic Conducting Films
Authors: Bloomenthal S.
Published: January 2005

Immutable conducting films, which adhere to any clean solid have been formed from synthetic resin solutions holding finely ground carbon in suspension. Values of surface resistivity for uniformly thin films were secured in the range 15 to 106 ohms referred to unit area of surface. When the thickness is held constant, the resistivity depends mainly upon the proportion of binder present and the kind of carbon used. The experimental error in repeating values of resistance with a given suspension is about ±20 percent. The dependence of resistance upon resin content of the film appears to be in accord with the views of Frenkel concerning gap contacts and in definite disagreement with the classical Maxwell theory of composite conductors. The behavior of various types of carbon, when used in the films, can be predicted qualitatively from electrical measurements made upon powdered samples subjected to high pressure. Absorption of moisture by a film leads to a rise in resistance.
Fluctuation Noise in Vacuum Tubes
Authors: Pearson G. L.
Published: January 2005

The fluctuation noises originating in vacuum tubes are treated theoretically under the following headings: (1) thermal agitation in the internal plate resistance of the tube, (2) shot effect and flicker effect from space current in the presence of space charge, (3) shot effect from electrons produced by collision ionization and secondary emission, and (4) space charge fluctuations due to positive ions. It is shown that thermal agitation in the plate circuit is the most important factor and should fix the noise level in low noise vacuum tubes; shot noise and flicker noise are very small in tubes where complete temperature saturation is approached; shot noise from secondary electrons is negligible under ordinary conditions; and noise from space charge fluctuation due to positive ions is usually responsible for the difference between thermal noise in the plate circuit and total tube noise. A method is deduced for the accurate rating of the noise level of tubes in terms of the input resistance which produces the equivalent thermal noise. Quantitative noise measurements by this method are reported on four different types of vacuum tubes which are suitable for use in the initial stage of high gain amplifiers. Under proper operating conditions the noise of these tubes approaches that of thermal agitation in their plate circuits at the higher frequencies and is 0.54 to 2.18×10−16 mean square volts per cycle band width in the frequency range from 200 to 15,000 cycles per second. Below 200 cycles per second the noise is somewhat larger. The minimum noise in different types of vacuum tube circuits is discussed. These include input circuits for high gain amplifiers, ionization chamber and linear amplifier for detecting corpuscular or electromagnetic radiation, and photoelectric cell and linear amplifier for measuring light signals. With the aid of these results it is possible to design circuits having the maximum signal-to-noise ratio obtainable with the best vacuum tubes now available.
Two Fluid Systems in Porous Media. The Encroachment of Water into an Oil Sand
Authors: Muskat Morris
Published: January 2005

The problem of the encroachment of water into an oil sand is formulated as a new type of potential problem, namely, that of finding potential distributions in two regions of different ``constants'' (``conductivities'') which are separated by a surface, each point of which has a velocity proportional to the vector gradient of the potential at the point, and such that the area swept out by the moving interface assumes the ``constant'' appropriate to that of the encroaching side of the interface. The cases of strictly linear, radial and spherical systems, in which the shapes of the interfaces are evident from symmetry requirements, are solved in detail and discussed graphically. The zeroth approximation to the general problem which gives the history of a line of fluid particles in a homogeneous system is also treated in detail. Analytical and graphical solutions are presented for (1) systems with elliptical boundaries, (2) an infinite linear source driving fluid into an isolated sink, and (3) the history of a ring of fluid particles travelling from a source to a sink. The relation of the analytical results to the practical problems of the encroachment of water into oil bearing sands is discussed both for the solutions of the general problem and those of the zeroth approximation.
An Experimental Study of the Motion of Particles in Systems of Complex Potential Distribution
Authors: Wyckoff R. D. , Botset H. G.
Published: January 2005

A method is described whereby the motion of the interface between two liquids of equal viscosity and density moving through a porous medium in systems of complex pressure distribution may be obtained by the use of electrolytic models. Experimental results for certain simple cases are compared with results obtained analytically and shown to be accurate to within 95–98 percent. Illustrations are given of more complex cases showing the application of these models to some practical problems of oil field technology.
The Radium Content of Some Connate Waters
Authors: Botset Holbrook G.
Published: January 2005

A method is described for measuring the radium content of natural waters. The method is shown to be accurate to within a few percent for concentrations as low as 100×10−12 g Ra per liter. Results are given of measurements on several connate waters from mid-continent oil fields. A correlation between radium and calcium content of the waters is indicated. Samples taken from the same wells over a period of several months indicate that the radium concentration is a definite property of a connate water.
Instantaneous Speeds in Air of Explosion Reports at Short Distances from the Source
Authors: Partlo F. L. , Service Jerry H.
Published: January 2005

In the first series of measurements the source was one No. 6 blasting cap, while in the second series one pound of 50 percent nitroglycerine stick dynamite was used as source. A telephone carbon button microphone was the receiver and was held fixed in location while shots were fired successively at 5, 8, 12.5, 25, 35, 50, 100 and 600 meter distances. A two-element string oscillograph was used for timing, one element recording the instant of firing, the other element recording the arrival of the wave at the microphone. The work was done at time of no perceptible wind; air temperatures were measured carefully; no humidity measurements were made. Travel times could be read reliably to 10−4 second and distance measurements were at least correspondingly good. Instantaneous speeds were obtained by plotting time computed minus time observed against distance and measuring slopes of the resulting curve. Since this work was incidental to seismic prospecting, the observations were not quite as numerous as those of von Angerer and Ladenburg. However, the results are similar as regards abnormally high speeds near the source. Also, the use of instantaneous speeds appears to show abnormally low speeds a little farther from the source, perhaps masked in the work of von Angerer and Ladenburg due to the use by them of average speeds instead of instantaneous speeds.
A Note on Mixed Boundary Value Problems in Logarithmic Potential Theory
Authors: Muskat Morris
Published: January 2005

A method is given for solving logarithmic potential problems in which the potential is preassigned over part of the boundary and the normal derivative over the remainder. A ``mixed'' Green's function is defined such that it vanishes over part of the boundary of interest and its normal derivative vanishes over the remainder, and the solution for the logarithmic potential is expressed in terms of this function and the boundary conditions by means of Green's theorem. Taking the case of the infinite quadrant as the ``prototype'' region the solutions for other regions such as the infinite half plane, infinite and semi-infinite strips, and the circle are obtained by mapping them on the infinite quadrant; these are illustrated by several specific examples.
On Electric Charges of Disperse Systems Which Are the Seats of Physico-Chemical Reactions
Authors: Rashevsky N.
Published: January 2005

In a number of previous papers a mathematical study was made of small drops, which either absorb or produce some substances by virtue of physico-chemical reactions. This creates in the drop and in the surrounding medium gradients of concentrations of corresponding substances. In this note it is pointed out that when the reacting substances are ionized, these gradients will result in the appearance of electric charges and electric fields. An estimation shows that they are quite comparable with electric charges, produced by other factors in disperse systems. The fundamental property of the charges here considered is that they disappear as soon as the reactions cease. Their importance in biological systems is pointed out.
The Mechanism of Division of Small Liquid Systems Which Are the Seats of Physico-Chemical Reactions II. Instability of Two-Phase Systems
Authors: Rashevsky N.
Published: January 2005

In continuation of a previous paper, the same mathematical method is applied to a system, consisting of two spherical concentric drops, under the assumption, that a reaction takes place only in the outer larger drop, but not in the inner one. It is found, however, that even in that case the inner drop may become unstable for infinitesimal deformations, and spontaneously elongate.
A Determination of the Refractive Index of Vitreous Silica and the Calibration of Silica Refraction Thermometers Between 18° and −200°C
Authors: Austin J. B. , Pierce R. H. H.
Published: January 2005

The variation with temperature of the refractive index of fused silica for the helium line 5877.2A has been determined between 18° and −200°C and the results have been applied to the calibration of vitreous silica refraction thermometers at low temperatures. These data have been correlated with measurements at high temperatures. It is found that the refractive index between −200°C and 1000°C can be represented by the equation n=1.45657+0.001553 t/100+0.00219 e−0.33t/100.
Shot Effect and Thermal Agitation in an Electron Current Limited by Space Charge
Authors: Pearson G. L.
Published: January 2005

Experimental evidence is presented which shows that shot effect is decreased by space charge and that the internal impedance of a vacuum tube is subject to thermal agitation.
A Study of Arc Temperatures by an Optical Method
Authors: Suits C. G.
Published: January 2005

Sound waves passing through arcs in air are photographed with a rotating mirror camera, whereby the sound velocity in the arc core is determined. From the observed sound velocity the arc temperature may be calculated by a method previously described. The arcs measured by this method, together with the sound velocities and corresponding temperatures, are: Cored carbon1.85×105 cm sec.−15500∘KNaCl cored C1.574740Al cored C2.146160W cored C2.176220W 6 mm electrodes2.045950W 9.5 mm electrodes2.276440W–Fe2.136150Fe–Fe welding arc2.086020The experimental error corresponds to ±100° at 5500°K. The experimental requirements of the sound source are discussed in detail. The gas temperature across the arc core is found to be constant within the error of observation. For most of the arcs studied the current density and electric gradients have also been measured, so that the data may be used as a test of the thermal ionization theory. The ``effective ionization potential (I.P.)'' of the arc gas is in all cases above the I.P. of the metallic vapor and below that of nitrogen. For the W arcs the effective I.P. is 15 volts, midway between the first I.P. of O2 and N2. For the arcs other than tungsten, this quantity is lowered appreciably by electrode vapor. A small partial pressure of Na lowers the arc temperature by approximately 1500°. The temperature of a welding arc between a coated iron welding rod and a steel plate is measured to be 6000°, from which the dissociation of the arc atmosphere is found to be 81 percent. This high degree of dissociation points to the importance of the dissociation-diffusion-recombination process for heat transfer in welding arcs and explains the recently reported negative results of attempts to arc weld in pure argon.
Flow Through Submerged Orifices
Authors: Kunz Jakob
Published: January 2005

From the measurements of F. E. Giesecke on the flow of liquids through submerged orifices two definite laws have been deduced. When the diaphragm is completely closed, the liquid flows backwards along the wall of the tube, and forward in a central vein, the radius of which has been calculated for laminar and turbulent flow. The theory by v. Kármán for turbulent flow has been applied to a tube of circular cross section. It is shown that both the backward flow and the jet issuing from the orifice are unstable. By an experiment it is made evident that a jet may sometimes describe a spiral motion.
Viscous Properties of Polyisobutylene
Authors: Ferry John D. , Parks George S.
Published: January 2005

The viscosity of polyisobutylene (molecular weight about 4900) has been studied from 70°C to 175°C with a falling sphere viscometer and from −53°C to 24°C with a concentric cylinder viscometer. In the measurements with the latter apparatus, elastico-viscous effects appeared, and the viscous behavior was non-Newtonian. The apparent viscosities were accordingly extrapolated to zero torque to give values for the viscosity at zero shear. The viscosity ranges from 19 poises at 175°C to 1010 poises at −53°C, showing a rather low temperature coefficient. At −76°C, the midpoint of the ``transition region'' for polyisobutylene glass, the viscosity has an extrapolated value of about 1013 poises, in agreement with a general rule for glass-forming materials. Macroscopic and microscopic interpretations of viscosity anomalies are discussed.
Effect of Certain Discontinuities on the Pressure Distribution in a Loaded Soil
Authors: Biot M. A.
Published: January 2005

The pressure distribution due to a concentrated load on a semi-infinite elastic body is given by the well-known Boussinesq solution for either the two-dimensional or three-dimensional case. We here investigate the effect on such a pressure distribution, taken at the depth h, of the presence at that depth of a slippery rigid bed (case (b)); of a perfectly rough rigid bed (case (c)); and of a perfectly flexible but inextensible thin layer embedded in the material (case (d)). Both pressure distributions in the two and three-dimensional problems are calculated for each case, Fig. 5 and Fig. 6. Several authors have already investigated case (b) and case (c) in two dimensions (2), (3). Their results are in perfect accordance with ours. The author is indebted to Dr. A. Casagrande for suggesting this investigation as a contribution to the field of soil mechanics.
Magnetic Properties and Orientation of Ferromagnetic Particles II. Pyrrhotite
Authors: Davis C. W.
Published: January 2005

The effect of heat treatment and of particle orientation on the magnetic properties of granular pyrrhotite are discussed and illustrated by curves and data. Heat treatment which causes little or no chemical change alters pyrrhotite so that increased induction and remanence and decreased coercive force result. Particles aligned in a filed parallel to that used in their magnetic measurement showed greater induction and remanence but less coercive force than randomly oriented material, while cross-oriented particles showed the lowest induction and remanence but the greatest coercive force.
Space Charge in Liquid Dielectrics
Authors: Whitehead J. B. , Minor E. E.
Published: January 2005

Studies were made of the unequal potential distribution commonly observed in insulating liquids under continuous potential difference. The potential distribution between parallel plates is measured in two insulating oils for over-all voltages between 500 and 1500 volts, and at temperatures between 20 and 60°C. This distribution is produced by an accumulation of space charge near the electrodes which accumulation, however, extends measurably into the volume of the liquid. The amount of space charge as computed from the potential distribution increases with increase of applied voltage and decreases with increase in temperature. On reversal of the applied voltage, the initial over-all conductivity is of approximately the same value as that preceding reversal. The initial current on reversal may remain constant over an appreciable interval, say from 1 to 4 sec. Following the initial constant value, the reverse current rises sharply to a maximum from 2 to 6 times the initial constant value, and at first rapidly and then slowly decreases to the same long-time values as that of the preceding opposite potential. In this condition, a reversal of the foregoing pattern of potential distribution takes place.

It is suggested that two types of ion are involved in the space charge, one of high mobility, and the other of low mobility, due to the accumulation about it of an aggregate of neutral molecules. Oscillographic studies of the variation of current on reversal offer means for approximate computations of the mobility of the ions involved. The mobility of the ions in a given liquid may take a wide range of values. As between different oils and for the same oil at different temperatures, mobilities vary inversely as the viscosity. In a low viscosity insulating oil a high value of 10−4 cm/sec./volt/cm has been observed at 22°C.
Electrical Conduction Models for the Solution of Water Seepage Problems
Authors: Wyckoff R. D. , Reed D. W.
Published: January 2005

A method is described for the construction of electrical models with which to solve problems of the flow of liquids through porous media under the action of gravity. With these models the shape of the free surface and the extent of the surface of seepage are determined simultaneously with the potential distribution within the flow system. Four examples are given of the application of the method to the problem of the seepage of water through dams. In two cases the faces of the dams were assumed to be sloping, and in the others they were taken as vertical, the free surface and velocity distributions at the faces of one of the latter cases checking closely with those derived from an analytical solution of the problem. The method of applying these models to the study of more complex gravity flow systems is briefly indicated.
Dielectric Properties of Anodic Layers in Aluminum Electrolytic Condensers
Authors: Lilienfeld J. E. , Chandler L. , Goldman S.
Published: January 2005

With a new type of especially stable electrolytic capacitor, the dielectric properties of anodic layers are measured. The investigation shows that variations of the dielectric properties may be divided into two classes: lagging and nonlagging variations. Lagging variations, which include variations of the capacity and power factor with the operaing voltages, are especially characteristic of anodic layers. They arise from the fact that the structure (organization) of layers adjusts itself with changes of the operating conditions to a new dynamic equilibrium, within a short transition period. On the other hand, in regard to variations of the capacity and power factor with frequency, which are nonlagging variations, anodic layers are similar to other composite dielectrics. An oscillographic study of harmonics is made which verifies the lagging nature of the changes of capacity with the operating voltages (a.c. and d.c.) and demonstrates for the first time the existence of a nonlagging variation of the a.c. conductivity with voltage.
The Association by the Fluidity Method of Substances Which are Solid at Ordinary Temperatures
Authors: Bingham Eugene C. , Hatfield James E.
Published: January 2005

The fluidities of mixtures of benzoic acid and naphthalene with benzyl benzoate have been measured to show that it is possible to estimate the fluidity and association of benzoic acid and naphthalene below their melting points in a variety of ways; first, by using the undercooled liquid; second, by extrapolating the fluidity curve of the liquid; third, by extrapolating from a mixture to the pure substance in the undercooled state, and possibly in several solvents; fifth, by measurement of the various derivatives of the compound and extrapolating the association back to the mother substance; or, sixth, by measurement of other homologs in the same series, and extrapolating to the desired member. In this paper the last method is shown to be the most satisfactory. How far the method may be extended remains to be seen. Some such method must be resorted to in estimating the fluidity and association of substances which cannot be obtained in the fluid condition at the temperatures at which the fluidity is desired. The authors predict the fluidity curves of oxalic and malonic acids in the anhydrous form. The first does not melt before decomposing and the second is unstable. The method makes it desirable to obtain values of the association for representatives of the different classes of chemical compounds. The method may then be of practical use in obtaining the molecular weights of substances of very high molecular weight, particularly of substances of high association.
Some Viscosity Data for Boron Trioxide
Authors: Parks George S. , Spaght Monroe E.
Published: January 2005

The viscosities of four samples of pure molten boron trioxide have been measured between 267° and 443°C with a concentric cylinder viscometer. The results, representing true viscosity, range from 2.1×1011 to 2.1×105 poises and are consistent with earlier data obtained at much higher temperatures. A viscosity value in the neighborhood of 1013 to 1014 poises appears to be associated with the so-called transition region in this and other glassy, or amorphous, materials.
Comparison of the Temperatures in a Solid and Its Scaled Model
Authors: Churchill R. V.
Published: January 2005

If a solid is constructed of the same material and to scale with a body of any shape and subjected to initial and surface temperature conditions of the same character, properties can be derived to compare or contrast the temperatures at corresponding points in these solids. Seven properties are given in this paper, covering the cases of variable and steady temperatures of solids with and without radiation or convection at any part of the boundary, and with any fixed temperature distribution on the rest of the surface. The law used for the transfer of heat by radiation and convection is a very general one. The thermal coefficients are functions of the temperature. These properties are derived by substitutions of new variables into the heat equation and the boundary conditions. Some of the properties give important information about the effect of the size of a solid upon its rate of cooling or heating. All of the properties are useful in the determination of temperatures in any solid by measuring the temperatures in a large or small scale model.
Magnetic Anisotropy in Silicon Steel
Authors: Sixtus K. J.
Published: January 2005

In hot rolled and in cold rolled sheets of silicon steel there are directions of easiest magnetization both before and after the final high temperature anneal. They are exhibited clearly by a disk suspended in a magnetic field. This property can be explained by the fact that a great part of the crystals composing the sample lie in a preferred orientation. The samples thus exhibit to a higher or smaller degree the anisotropic magnetic properties of single crystals. This non-random orientation of the crystals was shown for the annealed samples by a determination of the orientation of a great number of crystals by a light reflection method. The preferred orientations in cold rolled and hot rolled annealed samples differ substantially.
Growth of Crystals of Zinc Containing Cadmium by the Czochralski-Gomperz Method
Authors: Schilling Harold K.
Published: January 2005

In previous experiments it was found impossible to duplicate results of Hoyem and Tyndall who found a ``range'' for the successful growth of single crystals of zinc. Most specimens were ``optically mosaic.'' It is now shown that by adding Cd to Zn of highest purity, single crystals may be grown and that a ``range'' is connected with their growth. The range is similar to, but not identical with, that of Hoyem and Tyndall. Moreover, the shape of the range is dependent on the Cd content and on the speed of growth of the crystals. Optical mosaics as well as the changes of Hoyem and Tyndall are found outside of the range. In general optical mosaics are less frequent the higher the Cd content. Certain surface markings appear on the crystals even for only 0.20 percent Cd. These are believed to be identical with markings previously described by Rosbaud and Schmid and by Straumanis and probably indicate concentration of Cd along basal planes.
Mathematical Physics of Metabolizing Systems with Reference to Living Cells
Authors: Rashevsky N.
Published: January 2005

In previous papers we have investigated the conditions for spontaneous division of systems, which are seats of physico-chemical reactions of any kind. In this paper the previous general results are specialized for one particular set of reactions: oxidation of glucose and glycolysis. It is found, that whenever the two occur simultaneously, the ratio of their relative rates determines whether the system will divide spontaneously or not. Increased glycolysis favors spontaneous division. It is pointed out that the rapidly dividing cancer cells are characterized by an abnormally high rate of glycolysis.
A Multiple Space Charge Effect
Authors: Thatcher Everett W.
Published: January 2005

An investigation has been made of certain phenomena associated with space charge external to the grid which surrounds the cathode in a multi-grid tube. This paper reports a new effect, the essential feature of which is a negative plate current-emission characteristic. The conditions under which this phenomenon is observed are outlined. Results of experiments with double and triple grid tubes are summarized. In general, two points on the characteristic may be found for which the plate current is independent of small variations in emission, whether of a statistical or ``functional'' nature. An explanation is presented based on the interaction of multiple space charge. An application to the problem of high gain amplification is suggested.
Some Electrical Properties of Ceresin Wax
Authors: Wikstrom A.
Published: January 2005

A lower limit for the resistivity of commercial ceresin is set at 1.76×1019 ohm-cm if the voltage gradient is 2000 volts per cm the thickness of the sample is 0.214 cm and the temperature is 23°C. There is a comparatively large scattering of time functions used in the equation for the discharge current if expressed in accordance with Wagner's theory. The charge Q ``stored'' in ceresin is a function of time. At any time after the application of the voltage, this charge is proportional to the voltage. P/E was measured as a function of t. The increase is found to be more rapid than is claimed by other investigators. No variation of P/E with E was found. The results, however, are not quite conclusive, because of the inherent weakness of the method used in determining the polarization. The resistance R as defined by Richardson is calculated and found not to be constant for ceresin but to vary both with time and voltage.
Magnetic Properties and Orientation of Ferromagnetic Particles
Authors: Davis C. W.
Published: January 2005

Results of preliminary tests by direct methods show definitely that alignment of particles in a magnetic field increases their magnetization up to saturation and augments their remanence, but that coercive force is not noticeably affected.
The Telegraphist's Equations at Ultra-High Frequencies
Authors: King Ronold
Published: January 2005

The telegraphist's or long line equations are derived from the Maxwell field equations for ultra-high frequencies. By taking into account retardation and the time rate of change of current, a new circuit parameter is obtained in addition to the four usually found in the conventional low frequency equations. This new parameter integrates into the radiation resistance of the parallel wires. The approximations involved are discussed, and application is made to a specific example.
The Mechanism of the High Velocity of Propagation of Lightning Discharges
Authors: Cravath A. M. , Loeb L. B.
Published: January 2005

Observations by Schonland and Collens with Boys' camera show that the luminous tip of the leader stroke of the lightning discharge advances with a high velocity sometimes exceeding 3×109 cm per second. From the fact that electrons traveling 109 cm per second produce about 6000 new electrons per cm of actual path and that 6000 new electrons per cm in the direction of the field (i.e., α=6000) requires 4×106 volts per cm shows that to give the electrons a velocity in the direction of the field of 109 cm per second would require a field exceeding 4×106 volts per cm even at the tip of the stroke. The fields, and therefore the electron velocities, are certainly far less than this value. Accordingly the velocity of the tip greatly exceeds the velocity of the electrons in the tip. It is possible to account for this velocity as follows: Calculations based on justified assumptions concerning the conditions known to exist in a lightning stroke show that if the field just ahead of the tip averages 105 volts per cm for about one centimeter, ionization by collision by the electrons present in the gas before the stroke would be great enough to advance the tip at the observed rate. Such a field is found not too high to be consistent with the low conductivity of the leader path. In this way a propagation of the leader stroke of a velocity many times higher than the velocity of the electrons can be attained.
The Propagation of Rayleigh Waves in Heterogeneous Media
Authors: Pekeris Chaim L.
Published: January 2005

A method is given for obtaining a power series expansion in the wavelength for the Rayleigh wave velocity in a half-space whose density ρ and elastic constants λ and μ are functions of depth. This is followed by a discussion of the Rayleigh wave problem in media where λ = μ and μ(z) and ρ(z) are special cases of the type (ρ/ρ0) = (μ/μ0) = A cosh2 (α+βz).
A Note on a Problem in Conduction
Authors: Snoddy L. B.
Published: January 2005

The expression for the temperature distribution in a semi-infinite bar with heat supplied to the surface x=0 at a rate given by H=ktn(n=0, 1, 2 ···) is derived, assuming no radiation to the surrounding medium and an initial temperature of zero. Curves are given which enable the distribution in a bar of any material to be readily computed for n=0 and n=1. The solution serves equally well to determine the voltage variation in a semi-infinite non-inductive cable with entering current proportional to tn provided the heat constants are replaced by the appropriate electrical parameters.