Index of content:
Volume 12, Issue 6, 01 June 1941
12(1941); http://dx.doi.org/10.1063/1.1712925View Description Hide Description
12(1941); http://dx.doi.org/10.1063/1.1712926View Description Hide Description
12(1941); http://dx.doi.org/10.1063/1.1712929View Description Hide Description
12(1941); http://dx.doi.org/10.1063/1.1712930View Description Hide Description
A method of measuring the thermal conductivity of long rock core samples is described. It is an adaptation of Bidwell's method of measuring the thermal conductivity of metals. The core is packed in Silocel in a cylindrical container. Heat is supplied by a flat electric heater on one end of the core sample, and measurements of temperature are made along the core and at several radial distances in the insulator. Isothermal surfaces in the insulator are determined and found to be conical surfaces within several centimeters of the core. These are parallel for some distance along the core. Using this fact the conductivity of the core is computed relative to that of the Silocel. A value 5.92 × 10−3 cal./cm deg. sec. was obtained for a sample of Norite and 2.59 × 10−3 for a Pyrex rod at room temperature.
12(1941); http://dx.doi.org/10.1063/1.1712931View Description Hide Description
At the composition PtCo there exists a tetragonal superlattice with the AuCu structure. It is stable at 600°C, but forms a face‐centered‐cubic disordered phase at 1000°C. It is the incipient formation of this superlattice which is responsible for the superlative remanence and coercivity reported by Jellinghaus. At 400°C a body‐centered‐cubic phase begins to form. More than 50 atomic percent molybdenum and more than 35 atomic percent tungsten are soluble in platinum at 1000°C.
12(1941); http://dx.doi.org/10.1063/1.1712932View Description Hide Description
The streamline flow of air through highly porous wads of textile fibers is studied. The rate of flow is found to be twice as great for fibers parallel to flow as for fibers perpendicular to flow. Shape factors for the channels through which the flow takes place are determined and compared with those for the ideal case of Emersleben. The problem of measuring specific surface of high porosity wads is discussed.