Use of the superelements method to solve problems involving a longitudinal shear crack

The method of superelements is used to solve problems in fracture mechanics. A study is made of the torsion of a rod containing longitudinal cracks. It is shown that a square is a convenient form of superelement for the tip of a type-III crack. The stiffness matrix of the superelement is calculated and a numerical example is presented.Translated from Problemy Prochnosti, No. 3, pp. 73–77, March, 1995.     

The clinical significance of phasic duodenal intubation and ultrasonic monitoring of the gallbladder in healthy subjects

Hypoxic and low-temperature effects on the thermal regulation and the content of catecholamines (epinephrine--E and norepinephrine--NE) in mice have been compared. Continuous and repeated hypoxia brought about a significant drop of the rodent body temperature and heat content. Found was a significant elevation of catecholamines in the pituitary and adrenal tissues, and blood plasma with E prevalence after the continuous exposure. Repeated stimulus resulted in a more pronounced effect. Exception was the adrenal tissue where enhanced E and NE secretion into blood was noted. The uninterrupted and repeated cold conditions were also responsible for heat release. Continuous exposure to low temperature increased NE and decreased insignificantly E in blood and adrenal. Multiple stimulation increased sharply catecholamines concentration in blood plasma with the dominance of epinephrine in the pituitary gland, and norepinephrine in the adrenal.     

The use of nuclear reactors for high-temperature power-technological industrial processes

Conclusions Arising from the expected scales of development of high-temperature and power-capacity industrial establishments, and also from the reserves and disposition of fuel resources, it can be confirmed that the use of nuclear fuel for these factories can be completely justified. In this case, the actual economic expediency will depend on a sufficient level of technical reliability of the high-temperature complexes and nuclear reactors. The steam catalytic conversion of methane — which is one of the main links of the technological cycle for the large-scale production plants in the chemical industry for obtaining ammonia, methanol, higher alcohols, etc. — is in the maximum state of preparedness for achievement, based on the utilization of high-temperature heat from nuclear reactors. The conversion of methane for the chemical industry may become the technical basis for the introduction of nuclear reactors into ferrous metallurgical processes, the conversion of energy carriers and the production of hydrogen. The main technical problems lie in the field of transfer of the high-temperature heat from the core to the working space for carrying out the technological process, while observing the conditions of radiation safety of the production plant, the personnel and the environment. The search for an effective solution of the problem will be accomplished advantageously both in the direction of development of heat-transfer technical methods — which should allow gas-cooled nuclear reactors to be used for industrial technology — and also in the direction of development of new types of high-temperature nuclear reactors, directly oriented toward their introduction into industrial technology, e.g., based on the removal and transfer of heat from the core by radiative heat exchange, by means of a large-celled solid coolant.A preliminary estimate has shown that the incorporation of high-temperature nuclear reactors in industrial technology can be accompanied by a positive economic effect, if the specific capital investments in them do not exceed the specific capital investments in the power reactors of nuclear power stations by more than a factor of 1.5–2.0.Translated from Atomnaya Énergiya, Vol. 43, No. 6, pp. 432–437, December, 1977.