Numerical modeling of large elastoplastic strains in terms of principal stretches. II. Physical relations,calculation algorithm

The constitutive relations and plastic flow rule are derived from the thermodynamics equations. The known procedures of determining the plastic strain rate value are described. A calculation algorithm is presented that is based on the incremental loading, linearization of the virtual power equation and the projection method. A numerical example is presented.     

Modeling of helicopter behavior dynamics under the controlling action of the stabilization and control system

A possibility of evaluating dynamic response of a mechanical system to controlling actions of the automatic stabilization and control system is considered on the basis of a numerical experiment. Examples of design analysis are presented for a light-weight helicopter in which an autopilot is part of the control system. The finite element analysis is used in this paper.     

Intensification of heat exchange on the convex surface of an annular channel with continuous flow swirling

In this paper, the results of an experimental study concerning average heat transfer in an annular channel with flow swirling by an endless screw and spherical grooves on the convex surface are presented. Also analyzed is the heat and hydraulic efficiency of grooves application under conditions being considered.     

Testing for Year 2000 readiness: technical and management issues

The approach of the Year 2000 (Y2K) has called into question the condition of readiness of computer systems upon which organizations depend. Will these systems operate reliably after midnight, January 1, 2000, or will problems associated with date calculations cause failures that adversely affect users? This question has caused organizations to identify their critical systems, test these systems for Y2K problems, and take corrective action where necessary to ensure Y2K readiness. This paper examines various technical and management issues that Southwest Research Institute has dealt with in solving these problems     

Target-Handling Capacity of a Phased-Array Tracking Radar

The factors which affect the target-handling capacity of an agile-beamelectronically scanned multitarget-tracking radar are reviewed and analyze.Consideration is given to the choice of strategy for dwell allocation amongtargets, the choice of trajectory extrapolation algorithms for target tracking, and the determination of saturation target acquisition rates. Emphasisis placed upon radar systems with control computers having limited speed and memory, and recommendations are made for allocation strategy and targetytracking algorithms, based on uniform sampling, to be used in maximizing thetarget-handling capacity in this situation.     

Effect of clinostating on photosynthetic apparatus of pea plants.

The photosynthetic membrane composition and low temperature fluorescence spectra were analyzed for pea chloroplasts from control and clinostated plants. Clinorotation induces a decrease in the amount of the oligomeric form of the light-harvesting chlorophyll a/b complex (LHCII) and an increase of its monomeric form. Some changes in organization of photosystem 1 (PS1) complex were revealed as well. These changes are in accordance with the variations of fluorescence characteristics and photochemical activity.     

Growth of wheat under one tenth of the atmospheric pressure.

Wheat plants were grown in twin closed growth chambers under normal and reduced atmospheric pressures. For the first 22 days from sowing, the reduced pressure was maintained at 200 hPa, and at 100 hPa for the remaining 27 days until harvest. These pressures were obtained by evacuation of the chamber and adding oxygen (170 and 79 hPa respectively) and carbon dioxide (0.65 and 1.0 hPa respectively; about 2 and 3 times above the control). Eighty-seven per cent of the final dry mass was produce under 100 hPa treatment. Growth and development of wheat are not negatively affected by low pressure treatment. Compared to the control, final dry mass increased by 76%, leaf number by 133%, and ear number by 35%, probably due to elevation of CO2. Shortening of shoot parts and increases in chlorophyll and proteins content are not in accordance with a predicted CO2 effect and could be attributed to the N2 removal and the subsequent alteration in gas diffusion rate.     

Modelling of genetically engineered microorganisms introduction in closed artificial microcosms.

The possibility of introducing genetically engineered microorganisms (GEM) into simple biotic cycles of laboratory water microcosms was investigated. The survival of the recombinant strain Escherichia coli Z905 (Apr, Lux+) in microcosms depends on the type of model ecosystems. During the absence of algae blooming in the model ecosystem, the part of plasmid-containing cells E. coli decreased fast, and the structure of the plasmid was also modified. In conditions of algae blooming (Ankistrodesmus sp.) an almost total maintenance of plasmid-containing cells was observed in E. coli population. A mathematics model of GEM's behavior in water ecosystems with different level of complexity has been formulated. Mechanisms causing the difference in luminescent exhibition of different species are discussed, and attempts are made to forecast the GEM's behavior in water ecosystems.