Volume 2, Issue 5, 01 May 1932
Index of content:
2(1932); http://dx.doi.org/10.1063/1.1745059View Description Hide Description
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.
2(1932); http://dx.doi.org/10.1063/1.1745060View Description Hide Description
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.
2(1932); http://dx.doi.org/10.1063/1.1745061View Description Hide Description
Because of the equivalence of the pressure in a liquid bearing sand to a velocity potential, an analysis has been carried through of the potential theory of the electrical analogue of an artesian well partially penetrating a water bearing sand.
Part I. In Part I the method of analysis is illustrated by the solution of the problem of a hemispherical electrode imbedded in one of the faces of the disk. Two types of formulae are developed suitable for study of the potential distribution at small and large distances from the electrode respectively. The resistance of this system as a function of the disk thickness is computed and plotted.
Part II. In Part II is treated the more general problem of the potential distribution for a partially penetrating electrode, with a uniform flux density along the electrode surface. Separate formulae for the potential function are again derived that are convenient for discussion at small and large separations from the electrode. It is shown that they reduce in the limit of small penetrations to those of Part I and in the limit of complete penetration to well‐known radial flow formulae. Expressions are also given for the stream functions corresponding to the derived potential functions. Finally it is shown that when the flux density along the electrode is assumed to be constant the potential over the electrode is far from uniform, falling sharply near the electrode extremity to a value slightly more than half of that at the top of the electrode.
Part III. The problem of physical interest in which the electrode is at uniform potential is attacked in Part III. After discussing the case of a flux density over the electrode surface increasing with distance from the top the direct method of superposing discontinuous flux density elements is finally used to obtain electrodesurface potentials uniform to within 2 percent of the average surface value. The equivalence of this method to the direct solution of the integral equation for the problem is pointed out. The resistances of the disk for various electrode penetrations and disc thicknesses are then computed and plotted. From these a semi‐empirical approximation is derived permitting the resistances for other cases to be derived from a single expression without the necessity of first adjusting the electrode flux distribution so that its potential be uniform.
2(1932); http://dx.doi.org/10.1063/1.1745062View Description Hide Description
The desirable properties of rotary drilling fluid in the technique of boring oil wells are considered. An analysis of the problem of elimination of cuttings by differential settling with reclamation of the colloidal content of clay dispersions shows that viscosity should be lowered as much as possible when the density is held constant. It is demonstrated that lowering of viscosity results in a small lowering of pump pressure, even though the velocity of the mud‐fluid is increased to maintain constant carrying capacity for cuttings. Several chemicals have been found that cause remarkable lowering of the viscosity of clay drilling fluids. Suitable adjustment of the concentration of caustic soda in these chemical reagents imparts desirable thixotropic properties to the clay dispersion. The theoretical results of this study are applied to some of the practical problems of oil‐well drilling.
2(1932); http://dx.doi.org/10.1063/1.1745063View Description Hide Description
An electroscope and technique for measuring the radon content of soil gas are described. Measurements were made to answer several questions regarding the radon content of soil gas. It was found that there is no systematic increase of radon content with depth of penetration into a soil, that soil formations appear to have more or less characteristic radon contents, that high radon content of a soil gas is not necessarily an indication of the presence of a fault, and vice versa; and finally it is found that there is great local variation of radon content of soil gases.
Speed, Speed Factor and Power Input of Different Designs of Diffusion Pumps, and Remarks on Measurements of Speed2(1932); http://dx.doi.org/10.1063/1.1745064View Description Hide Description
The speed factor of a diffusion pump is defined as the ratio of its real speed to the ideal maximum speed. The fact that the speed factor is much less than unity is due to three causes, namely, the vapor dispersed through the slit, the nozzle chamber resistance and the diffuse reflection of gas molecules at the boundary of the vapor‐stream and at the condensing wall. Some effects on the speed are considered as being independent of the configuration. The following general conclusions result from the measurement of the speeds of different configurations. (a) In order to reduce the amount of dispersed vapor by the slit, the vapor nozzle should be divergent instead of being parallel; (b) in order to reduce the chamber resistance the space surrounding the slit should be large and the nozzle chamber should be cold; (c) there exists for each design a certain slit area at which the speed is maximum, but there has been no general rule to predetermine it; (d) in designing a large pump either a narrow throat annular nozzle or multiple nozzles can be used. In measuring speeds some precautions should not be overlooked, unless the results will be falsified: Either the determined speed will be too small or too large (pseudospeed).
2(1932); http://dx.doi.org/10.1063/1.1745065View Description Hide Description