Influence of structural factors on the macro- and micromechanisms of fracture of austenitic dispersion-hardening alloys with an interrupted type of decomposition. Report 1

The commercial alloy 36NKhTYu in various structural conditions differing in the type of decomposition, grain size, and degree of dispersion of Y'- and -phase hardening particles was investigated by high-voltage electron microscopy and determination of the mechanical properties in tension in fatigue tests. It was established that in the alloy with the original coarse grain size regardless of the type of structure being formed and the form of loading, fracture is primarily ductile, occurring by a dislocation-shear mechanism. The comparison of structures of different type that was made showed that the structure with interrupted precipitation of -phase has the highest fracture energy requirement as the result of the presence of plastic interlamellar layers, providing effective dissipation of the energy supplied in loading. Deformation and fracture of the fragmented and ultradispersed structures is controlled by collective rotational processes.Translated from Problemy Prochnosti, No. 10, pp. 23–28, October, 1992.     

Application of the monte carlo method in the processing of experimental data on dynamic deformation of materials

The article presents a method of processing the recorded diagram of deformations vs time t for the purpose of determining the time-dependent change of strain rate and acceleration. The method is based on the utilization of data of statistical tests (the Monte Carlo method) and the least squares method applied to the deviations of the functions (t) from the experimental curve at the specified number of points.Translated from Problemy Prochnosti, No. 8, pp. 20–22, August, 1992.     

Threshold phenomena in the excitation spectrum of liquid 4He

The elementary theory of threshold phenomena in the excitation spectrum of superfluid ⁴He is presented. The multiphonon threshold in the initial part of the spectrum and the two-roton threshold at energy 2 are discussed.     

Low-temperature nonequilibrium-ionization inert-gas plasma and MHD-generators

The main results of theoretical and experimental studies of low-temperature magnetized (>1) nonequilibrium-ionization plasma properties are reported. Such plasma is found to be more stable as compared to the equilibrium-ionization one. Development of ionization instability in such plasma results in the formation of striae oriented perpendicularly to the plasma velocity and not decreasing its effective electric conductivity. Thus, the possibility exists of designing an effective MHD-generator operating with the inert-gas plasma without admixtures in closed-cycle installations.Reported at the VIIIth All-Union Conference on Physics of Low-Temperature Plasma (Minsk, September 1991).St. Petersburg Branch of the All-Union Research Institute for Electromechanical Engineering. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 63, No. 2, pp. 161–164, August, 1992.     

Healthcare industry to benefit from 'Baby Bell' court ruling

Courts have cleared the way for regional Bell operating companies to sell electronic information. Although critics are fearful of the Baby Bells' power, others say the decision will open a myriad of possibilities that could have far-reaching effects on the healthcare industry.     

Effects of silicon powder structure of nitriding

A study has been made on how the structural state of the silicon affects the nitriding at 1200–1400C. As the initial powder becomes more defective, the nitriding accelerates, and there is an increase in the importance of reactions in the gas phase, with an increase in the proportion of the a modification of silicon nitride, and a tendency for elongated crystals to form.Translated from Poroshkovaya Metallurgiya, No. 10, pp. 1–7, October, 1992.     

Solar ultraviolet irradiation of human cornea, lens, and retina: equations of ocular irradiation

Photochemical damage of ocular tissues by solar radiation depends on the spectral composition of the radiation in the environment, the geometry of the coupling of that radiation to the eye, the spectral transmittances of the ocular components and any auxiliary lenses used, the spectral sensitivity of the irradiated tissue, the accumulated exposure dose, and the action of repair processes. This paper provides formulas for quantitative estimation of corneal, lenticular, and retinal UV irradiances from the sunlit environment under clear sky conditions. Applications of these formulas for ocular irradiation will be presented in subsequent papers for the cornea, lens, and retina, and the results will be evaluated using weighting functions for the sensitivity of ocular tissue.