Volume 3, Issue 3, 01 September 1932
Index of content:
Some Measurements on the Vapor Viscosities of the Two Common Pentanes, Two Pentenes, and Carbon Tetrachloride3(1932); http://dx.doi.org/10.1063/1.1745088View Description Hide Description
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.
3(1932); http://dx.doi.org/10.1063/1.1745090View Description Hide Description
An ideal soil is an assemblage of spheres packed to a definite porosity, and for statistical purposes may be represented by grains placed in hexagonal array, with adjacent grain centers equidistant and at a distance (2r+d), where r is the grain radius and d a spacing constant adjusted to suit the observed porosity. Three sets of capillaries, found to extend continuously throughout the packing, furnish the channels through which fluid crosses the soil body. The velocity through the mean capillary is calculated by a method essentially due to Slichter; and from this quantity, the sectional area of the mean capillary, and the number of capillaries per cm2, the quantity of fluid per sec., f, crossing a soil of section area s and length L, is found to be P is the porosity, D the diameter of the grains, η the viscosity of the fluid, and Δp the pressure difference under which the flow occurs. Intrinsic permeabilities computed from this equation are compared with values for carefully sized glass spheres and quartz sands observed experimentally by Green and Ampt. A further comparison with corresponding values calculated from Slichter's equation is given.
3(1932); http://dx.doi.org/10.1063/1.1745091View Description Hide Description
A study is made of the penetration of hydrogen through a very fine grained steel as compared to the usual grade of steel used in the construction of pressure equipment. The penetration is studied in specially constructed cylinders and found to take place at much lower pressure than had previously been recorded. The penetrating effect of hydrogen is observed at as low as 4000 atmospheres, whereas 9000 atmospheres is the lowest pressure previously recorded for this effect.
3(1932); http://dx.doi.org/10.1063/1.1745092View Description Hide Description
3(1932); http://dx.doi.org/10.1063/1.1745093View Description Hide Description
The attack of armor by competent projectiles involves a punching cycle of very short duration and extreme reactions. The characteristic results, with respect to the essential properties in the design of ship protection, have been investigated by means of simple dimensional forms, and a generalization has been made by reference to a penetration coefficient. The latter is a function of the penetration number (ratio of plate thickness to projectile diameter) and the obliquity of impact. A similar treatment of the absorption problem is outlined, and the special case of thin plate is of note in the implied linear velocity law of reaction. Conditions for extension in scale are stated and also certain convenient ratios for the estimation of the relative limits of nonsimilar systems.