ARTICLES BY BELL SYSTEM AUTHORS 485 



Note on the Inertia and Damping Constant of Ferromagnetic Domain Bound- 

 aries. C. KiTTEL.i Phys. Rev., v. 80, p. 918, Dec. 1, 1950. 



Reduction of SrO by Tungsten in Vacuum.* G. E. Moore,^ H. W. Allison,' 

 and J. Morrison.' Bibliography. Jl. Chem. Phys., v. 18, pp. 1579-1586, 

 Dec, 1950. 



Abstract — It is shown that in the temperature range 1150-1550°K, SrO 

 is reduced by tungsten in vacuum. Both the rate of the reaction and its 

 equilibrium constant can be calculated, giving values in substantial agree- 

 ment with the experiments, which were performed under conditions such that 

 both could be measured. The use of radioactive isotopes simplified the 

 experimental work. 



Vaporization of Strontium Oxide.* G. E. Moore,' H. W. Allison,' and 

 J. D. Struthers.' Bibliography. Jl. Chem. Phys., v. 18, pp. 1572-1579, 

 Dec, 1950. 



Abstract — ^The vapor pressure of SrO was measured by studying the 

 product evaporated from platinum filaments coated with SrO. Most of the 

 experiments employed radiactive isotopes. The possibility of systematic error 

 caused by chemical reduction of the oxide or by its thermal dissociation is 

 discussed. A value of Xo, the heat evaporation at 0°K computed from the 

 results, is used to evaluate precision and to derive a vapor-pressure equa- 

 tion. 



Millimeter Waves.* J. R. Pierce.' Electronics, v. 24, pp. 66-69, Jan., 1951. 



Effect of Stress-Free Edges in Plane Shear of a Flat Body.* W. T. Read.' 

 Jl. Applied Mech., v. 17, pp. 349-352, Dec, 1950. 



Abstract — This paper determines the tangential stiffness of a flat rectangu- 

 lar body, or shear pad, with a uniform relative tangential displacement on 

 the upper and lower surfaces. The state of stress differs from pure shear in 

 that the edges are stress-free. The correction to the stiffness in pure shear is 

 obtained as a function of Poisson's ratio and the length-to-thickness ratio. 

 The paper also illustrates the power of energy methods in furnishing ac- 

 curate approximations with a small amount of numerical work when only 

 over-all quantities, such as stiffness, are investigated. By manipulating 

 energy relations and using the Prager-Synge approximate method a few 

 hours of slide-rule computation was sufficient to determine both upper and 

 lower bounds for the stiffness. 



Growing Piezoelectric Crystals.* A. C. Walker.' Franklin Inst., J I., v. 

 250, pp. 481-524, Dec, 1950. 



Abstract — This paper is a summary of work carried out at the Bell Tele- 



* A reprint of this article may be obtained on request to the editor of the B. S. T, J. 

 ^B. T. L. 



