Volume 7, Issue 3, 01 March 1936
Index of content:
7(1936); http://dx.doi.org/10.1063/1.1745370View Description Hide Description
X‐ray radiography is industrially useful in the physical inspection of welded, cast, or assembled products. X‐ray diffraction analysis contributes to the understanding of the details of the processes of manufacturing and treatment of alloys, ceramics,glasses, textiles, and other materials. Both applications have led to the control and improvement of industrial processes and products.
7(1936); http://dx.doi.org/10.1063/1.1745366View Description Hide Description
A theory is given of the acid treatment of oil wells producing from limestone reservoirs, based upon the assumption of a potential flow of the liquid in the limestone. Calculations are presented for the increase in production capacity of a well resulting from an increase of the permeability in an annular ring surrounding the well bore, obtained by the reaction of the acid (HCl) with the limestone. It is found that the effects are maximal if this inner zone is initially of very low permeability, and is increased to a normal value, while if the permeability is normal originally, the effect of the acid treatment will be small. For limestones that are highly fractured, a representation is used wherein the fracture is replaced by a linear porous medium, of width equal to the fracture, bisecting the limestone proper and of a permeability that is equivalent to its fluid carrying capacity as given by the classical hydrodynamics for a free linear channel. The effect of the acid is then taken to be that of widening the fractures, thus increasing their effective permeability. The analysis here shows that increases in the production capacities as high as one hundred‐fold can be obtained in such fractured limestone systems for increases in the fracture width no greater than 1 mm, the effects being greatest when the initial fracture widths are small.
The Seepage Flux Under Dams of Extended Base Width and Under Coffer Dams Resting on Permeable Strata of Finite Thickness. I7(1936); http://dx.doi.org/10.1063/1.1745367View Description Hide Description
An exact theory is given of the seepage flux underneath dams of extended base width, with and without sheet piling, and under coffer dams with variable depths of excavation on the downstream side. The flux, per unit upstream‐downstream potential drop, is expressed in all cases as 1/2 the ratio of two complete elliptic integrals of the first kind, the modulus of that in the numerator being the comodulus of that in the denominator, these moduli completely characterizing the detailed geometry of the various individual systems. In all cases the seepage becomes logarithmically infinite with increasing thickness of the underlying permeable stratum. The effectiveness of the sheet piling in cutting down the seepage flux is a maximum when it is set at the heel or toe of the dam, and increases as the ratio of the thickness of the permeable stratum to the dam width increases. Although the flux decreases with increasing piling depth, a large portion of the flux will in general persist until the piling penetrates to the very bottom of the permeable stratum. The same is true with regard to the penetration of coffer dams. The pressure distribution at the base of dams of finite width resting upon permeable strata is found to be only slightly different from that with infinitely thick underlying beds, except when the thickness of the permeable stratum is appreciably smaller than the width of the dam.
7(1936); http://dx.doi.org/10.1063/1.1745368View Description Hide Description
Previous investigators had found that an electric field would change the viscosity of some liquids. This paper deals with this effect of an electric field on the viscosity and some of the factors upon which it is dependent. A rotating cylinder type of viscosimeter was used, the two cylinders being insulated from each other and the potential applied between them. Several liquids were investigated, some polar and some nonpolar. Nonpolar liquids showed zero effect, while polar liquids showed effects which were dependent on their polar moment. Changes in viscosity up to 200 percent were measured using fields up to 2000 volts/cm. It was also found that the effect was dependent on the velocity gradient present in the liquid.
7(1936); http://dx.doi.org/10.1063/1.1745369View Description Hide Description
The behavior of resistance‐capacity coupled amplifiers is studied with regard to their behavior as resonant networks. Expressions are obtained for the optimum value of circuit constants and the design procedure developed. Tuning at one cycle per second has been successfully applied to low noise amplifiers.