bluuebunny/crossref_metadata_2025 huggingface dataset:
PHYSICS IN THE STUDY OF PIGMENT DISPERSIONS
Authors: Steele F. A.
Published: January 2005

The study of colloids has reached the point where many important contributions are coming from physicists. Even more attention from physicists will be required if this science is to progress as it should. A suitable dispersion of zinc oxide in kerosene has a high yield value and marked plastic properties. A few drops of a dispersing agent added to this mixture largely destroys its plastic properties and greatly increases its fluidity. It is well established that the dispersing agent accomplishes this result by decreasing the interfacial tension and thereby destroying the flocculation of the pigment. In certain cases in paints, however, there is reason to believe an entirely different phenomenon is responsible for yield value and plasticity. Much work with the tools of the physicist is indicated in the solution of this problem. There is much to be done in the study of solid-liquid interfacial tension, adsorption layers, interfacial potentials, and the dielectric properties of colloids before these problems are to be solved. The behavior of pigments in rubber is also discussed.
THE ELECTRIC CONDUCTIVITY AND CAPACITY OF DISPERSE SYSTEMS
Authors: Fricke Hugo
Published: January 2005

This report refers in particular to suspensions of biological cells. The interior of a biological cell is a well-conducting salt solution, but at its surface polarization or the presence of a nonconducting membrane obstructs the passage of an electric current with a resulting low conductivity and high dielectric constant of the suspension. The theory for the passage of an alternating current through a suspension of this type is dealt with and experimental work with various kinds of suspensions such as cream, wet sand, blood, and animal tissue, is described to show the applicability of the theory. The determination of the volume concentration of suspensions, of the form factor of the suspended particles, of the thickness of surface membranes, and of the interior conductivity of living cells, are instances of practical applications.
THREE METHODS OF STUDYING CAPILLARY STRUCTURE AS APPLIED TO WOOD
Authors: Stamm Alfred J.
Published: January 2005

Three different physical methods for studying the capillary structure of porous materials are developed and applied to the study of the fine effective continuous capillary structure of wood. The three characteristic capillary properties measured are, (1) the ratio of effective capillary cross section to the effective length, (2) the average effective capillary radius, and (3) the maximum effective capillary radius. Some of the important characteristics of the porous structure of wood are briefly presented in order to show that the major part of the void structure, the fiber cavities, have very little to do with the permeability of wood. The pores in the pit membranes which connect the adjacent fiber cavities are shown to be the structure effective in controlling permeability of wood. The pores in the pit membranes in general, are below microscopic visibility, thus necessitating other means of study. The ratio of the effective capillary cross section to the effective capillary length is determined from electrical resistance measurements of strong salt solutions filling the void structure and from the specific resistance of the salt solutions in bulk. Strong salt solutions are used in order to make the surface conductivity negligible as well as the conductivity of the swollen cell wall. The average effective capillary radius is determined by combining the results of the preceeding measurements with results obtained from hydrostatic flow studies of a continuous water phase extending through the section. Poiseuille's law is used for the calculations. A differential pressure drop apparatus was devised for these measurements in which the flow of liquid through a standard capillary tube and the test specimen connected in series is determined by measuring the pressure drop through each. The maximum effective capillary radius is determined by measuring the gas pressure required to overcome the effect of the surface tension of water in the capillary systems. The data show the large differences between the fine capillary structure of heartwood and of sapwood.
SOME COLLOIDAL PROPERTIES OF BENTONITE SUSPENSIONS
Authors: Ambrose H. A. , Loomis A. G.
Published: January 2005

A study of the swelling and gelling properties of bentonite dispersions has been made in connection with the increasing use of this mineral for drilling oil wells. It is shown that the emulsoid type of colloids present responds to changes in the pH of the dispersion medium with respect to rate of settling, viscosity and swelling, thus behaving as a typical hydrophilic colloid. The curve for percent of solid matter settled in a definite time as ordinate against the pH shows a maximum at the isoelectric point, with minima on each side of this point, corresponding to the points of maximum adsorption. As the pH is further increased or decreased flocculation begins with increased rate of settling. The viscosity curve is closely related to the rate of settling curve, showing maxima and minima corresponding to the electro-viscous effect. Maximum swelling occurs at approximately the point of maximum viscosity. Methods are given for controlling the swelling of bentonites. Relaxation curves are given for bentonite suspensions and utilized to explain the suspension qualities of these sols for heavy mineral dispersions, such as barytes or amorphous silica. A few applications of bentonite sols to the drilling of oil wells are given.
TEMPERATURE DISTRIBUTION IN SOLID BODIES DURING HEATING OR COOLING
Authors: Austin J. B.
Published: January 2005

Most treatments of the problem of temperature distribution in a solid body during heating or cooling assume that the change in surface temperature is either instantaneous or linear with time. Experience shows that in many cases of practical importance the increase in surface temperature may be represented by a simple exponential function of the time. Equations for the distribution of temperature within a body when the surface is heated in accordance with this exponential relation have been derived for the following shapes: (1) rectangular parallelopiped (brick); (1a) rectangular rod; (1b) slab; (2) cylinder; (2a) cylindrical rod; (3) sphere. These equations also represent the general case of diffusion under the given boundary conditions and apply, therefore, equally well to problems such as the diffusion of one substance into another, as for instance, one metal into another.
SOME THERMIONIC PROPERTIES OF BARIUM FILMS ADSORBED ON TUNGSTEN
Authors: Nelson Herbert
Published: January 2005

An investigation has been made of some thermionic properties of a barium film adsorbed on tungsten for various values of θ, the fraction of the surface covered with barium. The experimental tube was so constructed that the measurements could be made on a small area of the filament in order that errors due to lead losses, non-uniformities, and voltage drop along the filament might be minimized. An electrometer vacuum tube was used to measure the electron currents. The experimental results obtained by Eglin were confirmed, i.e. the thermionic activity of the composite surface was found to increase with θ until an optimum value was reached after which further deposit of barium caused the activity to decrease. As a result of prolonged deposition, a steady value of the activity was reached which did not change appreciably or regularly with further deposition. The change in C.D.P. was found to be directly proportional to the change in Tθ, the absolute temperature of the filament required to give an arbitrarily fixed value of electron emission. It is significant that the factor of proportionality for all values of the activity higher than the steady value reached after prolonged deposition was found to be different than that obtained for the values which were lower. The distribution of velocities of the emitted electrons was found to be Maxwellian for all values of θ. The construction of the experimental tube was found to be unsuitable for studying the effect of field intensity on the activity. Thus the results obtained pertaining to this effect are of little significance.
THE EFFECT OF THE PRESENCE OF A GRID UPON CERTAIN CHARACTERISTICS OF THE AIRFLOW AT THE SURFACE OF AN AIRFOIL
Authors: Scott Merit
Published: January 2005

In a previous article it was reported that the heat dissipation per unit area from the surface of an airfoil, as measured by resistance strips mounted parallel to the span and flush with the surface, is characteristic of the airflow. An integral relation was set up from which it was shown that the coefficient of heat dissipation is proportional to the velocity gradient at the surface of the airfoil and hence to the viscous resistance. The effect of the presence of a grid upon the above mentioned characteristics has now been observed and comprises the subject of this paper. Experimental data are presented to show the changes in the heat dissipation for different parts of the airflow due to grids of varying fineness and spacing, due to changes of angle of attack and due to changes in location of the grids with respect to the airfoil. In general, the heat dissipation is increased whenever a grid is present to induce turbulence in the air stream and the effect is maximum at about 0.6 x/c. It is concluded that near the leading edge there exists a region that serves rapidly to damp the turbulence.
THE LIMITATIONS AND ADAPTABILITY OF ULTRAMICROSCOPES TO THE STUDY OF COLLOID SYSTEMS
Authors: Foster L. V.
Published: January 2005

Ultramicroscopes are of two distinctly different types. The best known is the cardioid ultramicroscope in which the illuminating portion produces a hollow cone of large angular aperture with its apex at the object. The observing system is a microscope consisting of a high aperture objective of angular aperture slightly less than that of the hollow cone and a high power eyepiece. The other is the slit ultramicroscope. The illumination system in the slit ultramicroscope is perpendicular to the observing system. Both systems are of high numerical aperture, but no direct light can enter the observation system. Details of construction of both types of ultramicroscopes and their sensitiveness of adjustment are discussed. Expressions of their limitations in colloid microscopy are given.
CONDUCTIVITIES OF LOW ORDER IN HYDROCARBONS AND TRANSFORMER OIL
Authors: Welo Lars A.
Published: January 2005

A method is described for removing moisture, air and soluble and suspended matter from oils and hydrocarbons in preparation for measurements of the d.c. conductivities and the power factors. The method at the same time provides for cleaning of the measuring cell and insures that no contamination occurs while measurements are being made. Normal decane, transformer oil and dimethyl octane were studied. In each case, d.c. conductivities in the lower range of 10−18 ohm−1 cm−1 were obtained, suggesting that if individual hydrocarbons have characteristic d.c. conductivities they must be of the order 10−19 or lower. In each substance the power factor was reduced to cos θ=0.0004 at room temperatures. A normal temperature-power factor function was found for the purified transformer oil. Near saturation was observed at the early stages of purification. Then, as purification proceeded, there was approach to Ohm's law, and finally approach to saturation again. It is pointed out that saturation at the early stages is the unexpected and unexplained feature. Some time-current curves and volt-ampere characteristics bearing on the phenomenon of electrical cleaning are included.
NATURAL OBSERVATION LIMIT OF RADIOMETRIC MEASUREMENTS
Authors: Cartwright C. Hawley
Published: January 2005

The sensitivities of thermocouples, radiomicrometers, bolometers, expansiometers and radiometers are compared by determining the minimum amount of energy that can be detected by a single observation. The instruments are considered to be critically damped and the accuracy of the measurements to be limited by the Brownian motion fluctuations of the measuring device. A detectable deflection is arbitrarily taken as four times as large as the Brownian motion fluctuations. The theoretical considerations are included for their generality or for their direct bearing on the practical design and use of the instruments. A thermocouple with a galvanometer or a radiomicrometer is the most sensitive of the measuring instruments considered. By a single observation with a galvanometer of one sec. period, 3×10−11 gm·cal./sec. falling on a thermocouple receiver 1 mm2 should be detected. A complete theory of the vacuum bolometer is presented. The ideal sensitivity of a vacuum bolometer is approximately the same as for a thermocouple but practical difficulties make the bolometer less sensitive. The vacuum tube is less sensitive than a galvanometer for use with a thermocouple or bolometer. A thin bimetallic receiver would not be as sensitive as a thermocouple for making accurate radiometric measurements. A vacuum thermocouple is about 20 times more sensitive than a radiometer mostly because the gas pressure that is needed for the action of the radiometer only allows the receiver to be heated about 1/10th as high as a vacuum thermocouple receiver. The sensitivity of a critically damped galvanometer or radiometer, limited by the Brownian motion, is proportional to the square root of the period.
THE VARIATION IN THE SURFACE TENSION OF GAS-SATURATED PETROLEUM WITH PRESSURE OF SATURATION
Authors: Swartz C. A.
Published: January 2005

The surface tension of a number of samples of crude petroleum has been measured, by the capillary rise method, as a function of the pressure at which the oil is saturated with gas. Oils and natural gases were used which were obtained from various fields throughout the country. Carbon dioxide, air, and benzene were also used. The oils were saturated with the gases at various pressures up to 2000 pounds per square inch at a temperature of 31°C (88°F), and curves obtained to show how the surface tension varies with the saturation pressure. The results show that in all cases curves of the same general type are obtained, and at 2000 pounds pressure the surface tension has decreased by more than 50 percent. In one case the decrease was as much as 80 percent.
CAPILLARY CONDUCTION OF LIQUIDS THROUGH POROUS MEDIUMS
Authors: Richards L. A.
Published: January 2005

The flow of liquids in unsaturated porous mediums follows the ordinary laws of hydrodynamics, the motion being produced by gravity and the pressure gradient force acting in the liquid. By making use of Darcey's law, that flow is proportional to the forces producing flow, the equation K∇2ψ+∇K·∇ψ+g∂K/∂z=−ρsA∂ψ/∂t may be derived for the capillary conduction of liquids in porous mediums. It is possible experimentally to determine the capillary potential ψ=∫dp/ρ, the capillary conductivity K, which is defined by the flow equation q=K(g−▿ψ), and the capillary capacity A, which is the rate of change of the liquid content of the medium with respect to ψ. These variables are analogous, respectively, to the temperature, thermal conductivity, and thermal capacity in the case of heat flow. Data are presented and application of the equations is made for the capillary conduction of water through soil and clay but the mathematical formulations and the experimental methods developed may be used to express capillary flow for other liquids and mediums. The possible existance of a hysteresis effect between the capillary potential and moisture content of a porous medium is considered.
SOME EXPERIMENTS WITH GAS-FILLED Cs–O–Ag PHOTO CELLS
Authors: Kingdon K. H. , Thomson H. E.
Published: January 2005

The amplification of the cathode emission by argon is much greater for a tube with a photo-cathode, than for a tube of similar geometry equipped with a thermionic cathode. This difference is attributed to large secondary electron emission by positive ion bombardment of the photo-cathode. If the anode voltage of one of these argon-filled tubes is abruptly increased, the time lag in the resulting current change is of the order 5×10−5 sec. for the thermionic tube, but of the order 10−3 sec. for the photo-tube. This lag is attributed to the life of the positive ion charge on the spongy surface of the photo-cathode. Measurements of the spontaneous fluctuations in the current through a gas-filled photo-tube indicate that the ``noise'' is of low frequency and associated with the gas amplification effect.
THE USE OF GLYCOL-PHTHALIC ANHYDRIDE RESIN AS A HIGH-VACUUM CEMENT
Authors: Sager T. P. , Kennedy R. G.
Published: January 2005

By using ethylene glycol-phthalic anhydride resin to seal the top of a camera box in a magnetic spectrograph it was found that a high vacuum could be obtained after pumping a short time. The preparation of the resin and its characteristics are described.
A NEW METHOD OF DIELECTRIC CONSTANT MEASUREMENT AT RADIO FREQUENCIES
Authors: Andrews H. L.
Published: January 2005

A new method of making dielectric constant measurements on gases at radio frequencies is described. This method eliminates the difficult condenser calibration required by earlier heterodyne methods. In addition, the effect of certain errors in previous methods can be estimated. The dielectric constant is obtained in terms of a single frequency standard, whose absolute frequency can be determined by auxiliary apparatus described. The method has been used to measure the dielectric constant of nitrogen at room temperature over a pressure range from zero to seven atmospheres. All measurements were made at a frequency of 884 kilocycles. The final value of ε−1 at N.P.T.=0.000589 is probably correct in absolute value to better than 0.5 percent.
A ``MAGNETIC SHARPENER''
Authors: McKeehan L. W.
Published: January 2005

The claim that the mere placing of a double-edged safety razor blade upon the poles of a specially designed permanent magnet has a sharpening action has been investigated by studying the characteristics of the device and by testing the sharpness of blades so treated in comparison with untreated and with mechanically stropped blades. No definite ``magnetic sharpening'' was observed to occur in these tests.
PHOTOELECTRIC PROPERTIES OF THIN FILMS OF ALKALI METALS
Authors: Asao S.
Published: January 2005

Measurements are reported on the color sensitivities of various photoelectric tubes having cathodes made of alkali metals. A composite surface of R-Ag-RO-Ag of any alkali metal R shows a higher sensitivity over a wider range of wave-lengths than R-RO-Ag and has two peaks, one between 330 and 370 mμ, and one at about 500 mμ for potassium and 550 mμ for rubidium and between 700 and 800 mμ for caesium. If a gas filled lamp at 2700°K is used as a light source, photoelectric currents from vacuum photo-tubes are obtained sometimes as large as 29μa per lumen for potassium, and 10–15μa per lumen for rubidium, and 40–50μa per lumen for caesium. It is also reported that the potassium cell in combination with a proper filter would constitute a means for an ideal photometer.
IMPEDANCE CHARACTERISTICS OF LOADED LECHER SYSTEMS
Authors: Tonks Lewi
Published: January 2005

Simple formulas are developed for the impedance of short lengths of Lecher system terminated by resistances. This impedance is most simply expressible as a multiple of the surge impedance. The variation of impedance with system length is traced and certain simple relationships are found. It is shown that any system of loads across a Lecher system is equivalent to a certain length of system terminated by a certain resistance. The formulas account for Takagishi's double hump phenomenon and this phenomenon is applied to finding the bridge shortening of an actual bridge. A method of calculating resistance from a resonance curve is derived.
MAGNETIC SUSCEPTIBILITY OF SOME BINARY ALLOYS
Authors: Meara Francis L.
Published: January 2005

The magnetic susceptibilities of eight series of alloys: tin-thallium, antimony-thallium, thallium-cadmium, zinc-cadmium, lead-antimony, tin-antimony, cadmium-antimony and zinc-antimony have been investigated by Gouy's method. In three series,—antimony-cadmium, antimony-zinc and tin-antimony an intermetallic compound is indicated by an abrupt change in the slope of the susceptibility concentration curve. The compounds thus indicated are SnSb, CdSb, and ZnSb with some evidence for the compound Sn2Tl. There is nearly a linear relation between the susceptibility and the concentration of one of the constituents where the constituents form simple heterogeneous mixtures—a result best illustrated in the zinc-antimony series of alloys.
THE UNPOLARIZED RESISTIVITY OF GLASS
Authors: Robinson Denis M.
Published: January 2005

An experimental comparison has been made of three methods of measuring the unpolarized resistivity of glass and fused quartz over a temperature range from 20 to 500°C. At high temperatures all three methods are in quantitative agreement and give a straight line when the logarithm of the resistivity is plotted against the reciprocal of the absolute temperature. At lower temperatures, however, the a.c. curve deviates from this straight line, indicating an additional component of loss which does not exist on d.c. This additional loss may be due to the orientation of polar molecules, though no definite proof can be given. The results obtained by the other two methods, both with direct current, are in close agreement over the whole temperature range, and give without doubt the true unpolarized resistivity.
A PRECISION METHOD OF MEASURING SMALL CHANGES OF LATTICE SPACINGS OF METAL SINGLE CRYSTALS
Authors: Hergenrother Rudolf C.
Published: January 2005

A method of studying the progressive crystal lattice changes occurring in a series of alloys or mixed crystals is described. This method compares the Bragg angles of x-ray reflection from a standard crystal with those of the crystal being studied. The important features of the method are simplicity and high accuracy (0.002 percent), which is attained without the use of an accurately calibrated angle scale. The theory of the method is discussed and two examples of experimental data which have been obtained are given.
POTENTIAL DISTRIBUTION, RADIATION AND ELECTRICAL CONDUCTION IN PAPER
Authors: Baker Edward B. , James Robert F.
Published: January 2005

The nature of electrical conduction in paper is discussed, particularly with regard to the formation of potential discontinuities. Experiments are described which indicate the formation of soft x-rays in paper insulated cables under voltage. Methods of measurement of potential distribution in paper insulation are given, together with preliminary results, which show large electrode drops under certain conditions. The relation of these experiments to those of Reboul and Bodin is pointed out.
DIELECTRIC LOSS AND RELAXATION TIME IN ROSIN
Authors: Whitehead J. B.
Published: January 2005

The power factor, dielectric loss and capacitance at 60 cycles of abietic acid have been measured over the temperature range 20° to 100°C. Short time charge and discharge curves, beginning 0.001 sec. after the application or removal of voltage, taken with the amplifier oscillograph, have permitted direct measurement of the relaxation time over the same temperature range. It is shown in general that there are two principal components of the discharge curve which lead to two types of relaxation time, one being the principal factor in the dielectric loss at low temperatures, and the other at high temperatures. The discharge curves have been used for an analysis of the alternating current behavior following the method of von Schweidler. There is uniform agreement between measured and computed loss. With increasing temperature the dielectric constant rises from about 2.6 to 2.8 within the temperature interval 20° to 50°C, the maximum rate of rise being at about 30°, at which temperature the maximum of power factor is also observed. The results are discussed in the light of dielectric absorption in the Maxwell sense and of Debye's theory of polar molecules. The conclusion is reached that alternating current measurements at 60 cycles do not offer a promising method of distinguishing between the two theories, since the same behavior is predicted by each.
HEAT WAVES THROUGH INSULATING WALLS
Authors: Pugh Emerson M. , Houghten F. C.
Published: January 2005

For calculating the flow of heat through walls of buildings the steady state formula based upon average temperatures has been found inadequate. A solution for the periodic heat flow through such walls is given, which has been simplified so that it depends upon two dimensionless quantities f and β1, which are functions of the physical properties of the walls and the periodicity. Curves are given which make it possible to read off the solution directly as soon as f and β1 are known. An experimental check is given.
SOME ASPECTS OF ELECTRICAL PROSPECTING APPLIED IN LOCATING OIL STRUCTURES
Authors: Peters Leo J. , Bardeen John
Published: January 2005

Electrical prospecting is defined as the science and the art of determining the variations of the electrical constants (resistivity, magnetic permeability and the dielectric constant) of the earth's crust and of interpreting these variations in terms of geological structure. The most successful systems of prospecting are based on the study of resistivity variations. The basic assumption made is that in general changes of resistivity follow the bedding planes. Electrical methods of exploration may be divided into two classes, direct current methods and alternating current methods. In part II the fundamental theory of direct current method is discussed and a typical survey is described. Part III deals with the theory of alternating current methods, with particular reference to the optimum frequency to be used. It is shown that in general very low frequencies are desirable. Two alternating current surveys made by the Swedish American Prospecting Corporation are briefly described. In the conclusion (part IV) some of the difficulties of electrical prospecting are discussed. The depth to which investigations may be carried is limited. In the present stage of the art, it would take exceptionally favorable conditions to obtain reliable information much in excess of 2,000 feet. However, it is stated that improvements in methods of interpretation and in field technique should give electrical methods a definite field of usefulness in prospecting for oil.
VELOCITY OF ELASTIC WAVES IN GRANITE
Authors: Leet L. Don , Ewing W. Maurice
Published: January 2005

The velocity of elastic waves in granite was determined at Quincy and Rockport, Massachusetts, and Westerly, Rhode Island. The waves measured were generated by dynamite explosions. They were recorded by portable seismographs at distances ranging from fifty feet to four thousand six hundred feet. The observed velocities for longitudinal waves were: Quincy … …16,260± 70 ft./sec. or 4.96±0.02 km/sec.*Westerly … . 16,400±120 ft./sec. or 5.00±0.04 km/sec.Rockport … .16,670± 40 ft./sec. or 5.08±0.01 km/sec.Average… . .16,530± 90 ft./sec. or 5.04±0.03 km/sec.A three-component seismograph, used only at Quincy, recorded transverse waves, the velocity of which was 8150±90 ft/sec., or 2.48±0.03 km/sec. From the two velocities determined at Quincy and the density of specimens taken from the shooting location, 2.65 grams/cm3, values for the bulk modulus, k, compressibility, β, rigidity,μ, Poisson's Ratio, σ and Young's Modulus E, were obtained as follows: k=44±1×1010 dynes/cm2; β=2.28±0.05×10−12 cm2/dynes; μ=16.3±0.4×1010 dynes/cm2; σ=0.333±0.005; E=43±1×1010 dynes/cm2. The form of the time-distance curves, straight lines through the origin, indicated that the waves did not penetrate deeply. Accordingly, the values obtained are for pressures of only a few atmospheres. The bearings of these results upon earlier investigations of the elastic constants of granite are discussed. Although direct comparisons between laboratory and field results are not conclusive, they indicate that the Adams and Williamson curve is incorrect for pressures below 2,000 megabars, and that there is no marked difference between dynamically and statically determined compressibilities of granite.
THE CALCULATION OF THE MOTION OF THE GROUND FROM SEISMOGRAMS
Authors: Wilson H. A.
Published: January 2005

The equation of motion of a mechanical seismograph is −ẍ=ÿ+2kẏ+p2y where x is the ground displacement and y the seismograph deflection. This equation may be solved for y when x is supposed known or for x when y has been observed as a function of the time. In this paper both of these ways of solving the equation are considered. The motion of the seismograph due to a train of waves starting at t=0 is considered and also the motion due to the arrival of a single wave. In each case seismographs with several periodic times and either undamped or critically damped are considered. Curves are given showing the motion of the ground and the calculated motion of the seismograph. The motion of the ground corresponding to several simple assumed seismograms is also worked out and shown by means of curves. The motion corresponding to a given seismogram depends greatly on the periodic time and damping of the seismograph. Finally the ground motion is deduced from two actual seismograms due to dynamite explosions. An integraph is described which enables the calculations to be done more quickly.
A CATHODE-RAY FREQUENCY MULTIPLIER
Authors: Jamison Noel C.
Published: January 2005

A vacuum tube was constructed having a filament and slit arrangement for the production of a sheet of electrons, one pair of deflecting plates, and a receiving plate composed of a series of rectangular conductors. Adjacent conductors were insulated from one another and alternate conductors were in electrical connection. An alternating potential difference applied to the deflecting plates causes the electron beam to move across the surface of the receiving plate, current flowing first to one set of conductors and then to the other set. During one complete cycle of the deflecting plate field, the currents from the two sets of conductors will pulsate with frequencies which are multiples of the frequency applied to the deflecting plates. By applying steady potentials to the deflecting plates, the current to each set of conductors may be measured and plotted as a function of the deflecting plate potential difference. Such static characteristic curves were examined for widely different currents, potentials, and gas content of the tube. Tests with an alternating potential difference applied to the deflecting plates gave very definite indications of receiving plate currents of two, four, and six times the frequency of the applied field.
NEW THEORY AND DESIGN OF WAVE FILTERS
Authors: Cauer W.
Published: January 2005

A new mathematical theory of wave filters gives the following results: It is possible to realize as constant an image impedance as desired in the transmitting bands. In the new theory there is no mathematical difference in the consideration of proper attenuation or proper image impedance characteristics. In other words, the same attack applies in both cases. All known wave filters as far as they are symmetrical fourterminal networks or equivalent to such networks in series with a transformer, are contained in the filters of the new theory which comprises all possible filters of this kind. The new theory has been carried through practically to find out the most economical filter for any practical purpose. This results in many cases in solving a given practical question already solved by known methods with considerable saving of material. The chief aim of this paper is to show the relation between the new theory and the older design methods due to O. J. Zobel and other members of the Bell Laboratories.
INFLUENCE OF TEMPERATURE ON THE CRYSTAL STRUCTURE OF ELECTRODEPOSITED ANTIMONY
Authors: Kersten H.
Published: January 2005

It is shown by x-ray diffraction methods that ``explosive'' antimony is amorphous before exploding and crystalline afterward. It is also shown that the crystal structure of electrodeposited antimony is influenced by the temperature of the plating bath.
ELECTROMAGNETIC EQUATIONS AND SYSTEMS OF UNITS
Authors: Page Leigh
Published: January 2005

The electromagnetic equations are put in their most general form and the following criteria for a useful set of equations and sets of units are established: (1) there should be only one set of fundamental equations, (2) there should be two sets of units, one c .g. s. for the physicist and one practical for the engineer, (3) the eight internationally recognized units should be retained in the practical system, (4) the fundamental equations should be symmetrical in form. It is shown that these criteria can be fulfilled in an infinite variety of ways, of which the Heaviside-Lorentz system of equations provides the simplest. The relations between c. g. s. and practical units employing this system of equations are tabulated.
FURTHER STUDIES ON THE THEORY OF SPONTANEOUS DISPERSION OF SMALL LIQUID SYSTEMS WHICH ARE THE SEATS OF PHYSICO-CHEMICAL REACTIONS
Authors: Rashevsky N.
Published: January 2005

The treatment of the problem which was given in previous publications is generalized so as to include not only the part played by the changes of the surface tension, but also that played by osmotic forces. Whenever any reactions take place in a liquid drop of the kind considered previously, there is always a difference of concentrations inside and outside of the drop. The forces caused by this difference are such that they always tend to divide the drop. The surface tension counteracts this tendency. As a result of this, the drop will divide only above a critical size. Calculations of this critical size leads to dimensions of actual living cells.
Dielectric Properties of Some Glycols
Authors: White A. H. , Morgan S. O.
Published: January 2005

The Debye theory of polar molecules leads to the conclusion that the anomalous dispersion due to dipoles which has been observed at high frequencies should also be found at low frequencies. Supercooled glycols are viscous enough at low temperatures to show dispersion at low frequencies. Real and imaginary dielectric constant and power factor are calculated and their inter-relationships are discussed. Better than qualitative agreement with the Debye theory is observed in the pure pentandiol, but not in the solution measurement.
Development of Polar Characteristics in Insulating Oils
Authors: Stoops W. N.
Published: January 2005

It is shown that the decomposition in transformer oils may be followed rather closely by measuring the dielectric constant of the oils as they deteriorate in service, the method being sufficiently accurate to distinguish between different oils. These data are compared with those obtained on oils decomposed very much more rapidly in laboratory tests. The change in polar characteristics is definitely correlated with change in chemical characteristics. That the change in dielectric constant of the oils is due to the formation of polar molecules is shown by a study of the variation of the dielectric constant and power factor of the decomposed oils with temperature and frequency.
On the Ultra High-Frequency Oscillation of the Magnetostatic Vacuum Tube
Authors: Dehlinger Walter
Published: January 2005

A physical picture of the phenomena during the electronic oscillation in the magnetostatic oscillator is given. The notion of a critical radius for plate voltages varying between a larger and a smaller value than the critical voltage for a given constant magnetic field is developed. The value of the critical radius is calculated as a function of the voltage differences and the potential distribution. The flying time of the electrons is discussed in its relation to the voltage distribution, and the falling angle is expressed in a simple way.
Experimental Study of Parallel-Cut Piezoelectric Quartz Plates
Authors: Fox Gerald W. , Hutton W. G.
Published: January 2005

Y-cut piezoelectric quartz plates were studied with respect to the charges developed on the plates when oscillating near their resonant frequencies. The attractive force between crystal and electrodes was measured. Two methods for determining the piezoelectric voltage developed across the crystal are suggested. It is concluded from a study of crystal breakage that fracture is due to intense mechanical vibration.
An Electrostatic Alternator
Authors: Culver Charles A.
Published: January 2005

In electrical measurements and research work it is frequently necessary to have available a source of e.m.f. having a sine wave form. It is also desirable to be able to produce electrical wave forms having special contours. Existing means for producing special e.m.f. wave forms have serious limitations. By utilizing a continuously varying capacitance, means are developed whereby a pure sine wave, as well as special forms, may be produced. Filtering is not required. The theory underlying the production of any desired wave form is outlined. Factors which tend to modify the resultant wave form are pointed out.
A New Low Noise Vacuum Tube
Authors: Metcalf G. F. , Dickinson T. M.
Published: January 2005

When commercial vacuum tubes are used to amplify small low-frequency voltages it is found that random disturbances of the order of 100 to 1000 microvolts are present in the anode circuit. These disturbances exist almost entirely in the range below 100 cycles per second, and therefore fix the minimum voltage which can be measured over this low frequency band from 10 to 100 microvolts. These disturbances are shown to be caused by any or all of the following: (1) insulating material in or near electron path; (2) irregularity of filament emission; (3) gas; (4) positive ions emitted by filament; (5) insulating or foreign deposits on grid wires. A tube has been developed in which the above effects are removed or reduced to a point where the disturbances are nearly that of the shot effect of the electrons, as limited by space charge. This allows the amplification of low-frequency voltages of less than 1 microvolt over the entire frequency band below 100 cycles.
The Amplifier-Oscillograph Applied to the Study of Dielectrics With Continuous Potentials
Authors: Waldorf Sigmund K.
Published: January 2005

The underlying causes of the losses occurring in dielectrics when subjected to alternating stress have long been a subject for speculation. There have been a number of proposals of methods for linking such losses with the dielectric behavior under continuous or d-c. electrical stress. To investigate the validity of the suggestions for correlating the d-c. properties of dielectrics with their a-c. losses, the continuous currents flowing must be measured as soon as possible after the d-c. voltage is applied to or removed from the specimen. The development of the amplifier-oscillograph permits a much improved and satisfactory technique. With the apparatus and method described here, observations could be begun within one or two thousandths of a second after the specimen had had the d-c. voltage applied, or had been short-circuited and they could be continued as long as desired. By this method, a connected series of observations was obtained with a single cycle of voltage application, removal, and short circuiting of the specimen, greatly expediting the work and eliminating inaccuracies arising from changes in the dielectric sample during the long periods of time heretofore required for such studies. The apparatus employed consisted principally of a quick acting, spring-actuated switch for operating the specimen circuits rapidly, and a sensitive-amplifier-oscillograph for recording the dielectric currents. On operating, the quick acting switch shunted the geometric charge of the specimen to ground for a brief interval after applying voltage to the specimen, or short-circuiting it, and then connected the amplifier-oscillograph to the measuring circuit. The observations could be continued as long as desired with a D'Arsonval galvanometer of high sensitivity. The amplifier-oscillograph attained a sensitivity of 1.6×10−8 ampere per mm deflection, which is about 300,000 times that of the oscillograph alone. The vacuum tube amplifier which accomplished this extension of range was in three stages, pure resistance coupled for the accurate reproduction of continuous currents. Many precautions were taken and tests made to ensure the reliability of this instrument and its connecting circuit apparatus.
A Theory of Surface Conductance at an Electrolyte-Solid Interface
Authors: Cole Kenneth S.
Published: January 2005

An expression has been derived on the basis of the Maxwell-Boltzmann distribution and Poisson's equation for the tangential surface conductance of an electrolyte in contact with a charged plane surface. One part of this expression is analogous to the result given by Smoluchowski for a Helmholtz double layer, while the second part arises from the movement of the ions in the diffuse ion cloud under the applied electric field. The theory shows qualitative agreement with the data of Briggs for the conductance of univalent chloride solutions at a cellulose surface. For all but the most dilute solutions, the Smoluchowski term is negligible and the surface conductance is proportional to the charge density on the surface. The theory does not agree with the data for different anions and it is suggested that the discrepancy may be due to absorption phenomena. There may be a movement of the adsorbed ions or of a diffuse ion cloud resulting from the presence of adsorption potentials at a distance from the interface.
The X-Ray Method of Determining the Sizes of Sub-Microscopic Crystals
Authors: Cameron G. Harvey
Published: January 2005

A brief critical summary of the principal contributions published on the theory of the subject is presented, followed by the report of a series of experiments designed to test the methods which have been proposed. It is concluded that while relative measurements can be made with sufficient accuracy, absolute values cannot be relied on as yet. The results emphasize the necessity for careful attention to such details as the construction of the camera, the preparation of the sample, and the characteristics of the x-ray film and of the microphotometer.
Flow of Liquids through Porous Media under the Action of Gravity
Authors: Wyckoff R. D. , Botset H. G. , Muskat M.
Published: January 2005

Recent published results of studies on the flow of liquids through porous media under the action of gravity have shown wide disagreement in both the formulation and interpretation of the problem. A new attack on the problem has been carried out and has led to unambiguous answers to the questions of interest. Experiments on a radial sector of sand show that the old Dupuit formula of 1863 stating that the fluid outflow is proportional to the square of the differences in the fluid heights in the sand is exact within experimental error provided the fluid heights are replaced by fluid heads as measured at the sand bottom. Both the pressure distribution formula and the integrated expression for the fluid outflow are verified in detail. The cases where an added pressure head is superposed upon the gravity flow, heretofore not mentioned in the literature, behaves both with regard to its pressure distribution and fluid outflow as a direct superposition of the simple gravity flow and pure radial flow systems. A semi-quantitative treatment is given for the flow in the capillary zone above the main fluid body. It is necessary under certain experimental conditions to correct for the added flow carried by the capillary layer in addition to that induced by the gravity drive. In most practical cases the capillary flow may be ignored. A theoretical discussion is given of the conditions at the free surface of a gravity flow system and it is shown that nowhere on it can the slope exceed 45°. The results on the radial flow experiments are also generalized to give a method for treating general drives.
Some Measurements on the Vapor Viscosities of the Two Common Pentanes, Two Pentenes, and Carbon Tetrachloride
Authors: Bleakney William M.
Published: January 2005

The present work is a continuation of the investigations begun by Dr. R. K. Day on the behavior of vapors by means of accurate viscosity measurements. The instrument, designed and built by him, has been improved, and his results on normal and iso-pentane have been verified. In addition, measurements on two pentenes, similar in structure to the pentanes, have been made at room temperature, and the viscosity-pressure curves for all four hydrocarbons and also for CCl4 have been obtained at 100°C. A linear relation, with a negative slope, persists in all these curves, the slope for the hydrocarbons being considerably less at the higher temperature, while the curve for CCl4 is comparable to those for the hydrocarbons at room temperature. Following are the values of the constants in the equation η=η0(1−αp), the pressure being expressed in atmospheres.
The Crystal Structure of Black Nickel
Authors: Kersten H. , Maas Joseph
Published: January 2005

This paper shows by means of x-ray diffraction analysis that electrodeposited black nickel has an amorphous structure which changes to a crystalline structure when the deposit is heated.
A Semiportable Alternating-Current Susceptibility Meter
Authors: Barret William M.
Published: January 2005

This paper describes a semiportable alternating-current instrument that has been developed recently for measuring the magnetic susceptibility of geological samples. Its construction, basic theory, and operation are outlined briefly.
Chemical Treatment of Rotary Drilling Fluids. Release of Cuttings: Chemical vs. Mechanical Methods
Authors: Lawton H. C. , Ambrose H. A. , Loomis A. G.
Published: January 2005

The general problem of elimination of sand, cuttings, and gas from aqueous dispersions of clay, commonly used in the rotary method of drilling oil wells, with reclamation of the colloidal content of the drilling fluid, is considered. Various mechanical devices for this purpose are briefly described and available data compared with laboratory findings on the rates of settling of particles from clay drilling fluids after chemical treatment. The colloid physics underlying the efficiency of chemical treatment is discussed. Graphs are given showing the superiority of chemical treatment of drilling fluids as compared with mechanical methods for reclaiming spent fluids. Treatment by chemical reagents has the great advantage of requiring no new equipment or expensive installation, and individual wells may be treated economically. Certain recommendations are made for maximum efficiency of the chemical method for field practice.
An Inverter-Lamp for the Conversion of 60-Cycle Power into 1000-Cycle Modulated Light
Authors: Westendorp W. F.
Published: January 2005

A gaseous discharge lamp in combination with a special electrical circuit is described with which a high-efficiency conversion of 60-cycle a.c. power into 1000-cycle pulsating light is obtained. The efficiency of this device is 17 lumens per watt as compared to 6 lumens per watt for an incandescent lamp with a mechanical shutter. As the modulated light is designed for the use in beacons and for the detection by means of a photoelectric tube and tuned amplifier, the component of fundamental frequency is the only important one. In a mathematical analysis of different wave shapes, the fundamental component is calculated as a function of the average light output; also the efficiency of a modulated neon discharge.