Frictional assessment of magnesium stearate and palmitate lubricant powders

A method has been developed for the frictional assessment of powder lubricants using a shear-box tester similar to that employed by Jenike. One commercial magnesium stearate, three high-purity magnesium stearates and three high-purity magnesium palmitates were assessed using this method. Powders with a well-ordered crystal structure and particle shape have a lower initial maximum coefficient of friction μ_a. The difference between μ_a and μ_b, the equilibrium dynamic friction coefficient, gives an indication of lubricant film-forming propensity. The basic friction equation is obeyed by the powders for most of the load range studied but deviates slightly approaching zero normal load.     

Removing cesium radionuclides from sodium-potassium coolant

Translated from Atomnaya Énergiya, Vol. 66, No. 1., pp. 22–24, January, 1989.     

Analysis of performance of fuel elements of the BOR-60 reactor with vibrocompacted uranium-plutonium oxide fuel

Translated from Atomnaya Énergiya, Vol. 66, No. 5, pp. 299–302, May 1989.     

Long distance fiber-optic transmission of C-band microwave signals to and from a satellite antenna

We demonstrate here the use of high-speed semiconductor lasers and detectors with low loss optical fiber for the transmission of the 500-MHz C-band microwave signal spectrum to and from a satellite antenna. The optical system has low attenuation and large band, width, so the microwave signals can be transmitted directly at the microwave frequency (4 or 6 GHz) over 20 km of fiber without regeneration or qualization. The optical system introduces ≈ 1 dB or less of degradation for both low spectral density QPSK signals and high spectral density FM video signals present in typical satellite transmission systems. For the video signals, the signal to noise after AM conversion was reduced from 56 to 55 dB. The microwave drive level to the laser must be significantly larger (typically > -10 dBm) than the intensity noise of the laser, yet small enough (typically < 10 dBm) to reduce the intermodulation distortion signals to an acceptable level. The laser bias current must be several times threshold so that the resonance frequency is beyond the frequency band of interest (4-6 GHz in this case). A flat modulation response is then obtained, and the intensity noise and intermodulation levels are low.     

A Device for Measurements of Dielectric Characteristics of Liquid Crystalline Materials, Solid Substances, and Their Melts

The device developed allows one to measure the dielectric characteristics of solid substances and their melts at frequencies of 20–20000 Hz and in a wide temperature range of 20–250°C. The measured temperature dependencies of the dielectric permittivities of several molecular and liquid crystals (stilbene, diphenyl, naphthalene, cholesterylpelargonate, and 8OCB) are presented.