Stability of stochastic self-adjusting automatic control systems with after effect. I. mean square asymptotic stability of systems of linear stochastic differential-difference equations

The stability of stochastic self-adjusting automatic control systems with aftereffect is investigated. Theorems on the mean square stability of stochastic differential difference equations are proved, which allow the stability analysis of stochastic self-adjusting systems.     

Adaptive response of Listeria monocytogenes to heat and its impact on food safety

Listeria monocytogenes is an important food associated pathogen because of its relatively high heat resistance and ability to multiply in refrigeration temperatures. Its thermotolerance can be increased when its cells are subjected to heat shock. One- to eight-fold increase of D values of L. monocytogenes have been reported, depending on the heat shock duration, the temperature and the heating menstrum. This acquisition of heat tolerance is related to the induction of the synthesis of heat shock proteins (HSPs).The adaptive response of food pathogens has important consequences on the safety of thermally processed foods. It is believed that this is responsible for the frequent occurrence of deviations (tails and shoulders) during heat treatments that are observed in the exponential model of microbial inactivation. These deviations from log-linear kinetic especially encountered under mild heat treatments, mean that prediction of food safety can no longer rely upon D and z values. Adaptive response to heat must be considered when quantifying and modeling microbial inactivation during thermal processing in order to achieve microbiologically safe products without overly conservative heat processes. Therefore a more mechanistic approach is needed for more accurate predictions of thermal inactivation. Prerequisite to this model are thorough studies to understand how L. monocytogenes and other pathogens adapt their cellular physiology to overcome heat and other stresses.     

Lithium incorporation into thin films of vanadium oxides

Thin-film electrodes based on vanadium oxides have been obtained using the thermal oxidation of vanadium films deposited in vacuum. It is established that these electrodes admit the reversible incorporation of lithium from aprotic electrolytes and possess an initial capacity exceeding 250 mA h/g. The electrodes have good prospects for use in thin-film lithium ion batteries.     

Corrosion longevity of gas turbine blades protective coatings

Results obtained from long-term studies conducted at the NPO Central Boiler-Turbine Institute on determining corrosion longevity of gas turbine blade protective coatings applied using different methods are presented. It is found how the base and alloying elements of coatings, the ceramic layer thickness, and the corrosion resistance level of undercoat alloy influence the longevity of coatings.     

Nondestructive testing of steel rods

The possibility of the detection of hidden flaws in magnetization with a geomagnetic field was determined experimentally. Steel rods 3 mm in diameter and 2 m long, which were prepared from a wire that is used in shock absorber springs, were used as test objects.     

Heat pump cycles based on the AF–F transition in Fe–Rh alloys induced by tensile stress

The heat-pumping scheme based on the 1st order antiferromagnetism–ferromagnetism transition induced in FeRh alloy by one-dimensional tensile stress is proposed. Using the model S–T diagram for this alloy, the heat-pump cycles are drawn up based both on the transition latent heat absorption and emission when the transition is induced isothermally and on the change in alloy's temperature when the transition is induced adiabatically by applying tensile stress. The calculated values of heat coefficient φ for the cycles are 30 at ΔT=5 К and 20 at ΔT=10 К, where ΔT is the difference between the temperature surrounding and that of the heat receiver. These values are achieved using the tensile stress of 1·10⁹ Pa. The high values of φ make it possible to consider Fe–Rh alloys near the equiatomic composition as an effective refrigerant for elastocaloric heat-pumping near the room temperature.     

Analysis of stability of stochastic dynamic systems under Poisson perturbations. II. Stability of solutions in quadratic mean of systems of linear stochastic differential equations under Poisson perturbations

Necessary and sufficient conditions of asymptotic stability in quadratic mean are obtained for trivial solutions of systems of linear stochastic differential equations under Poisson perturbations. Model problems are analyzed. Part I of this article is published in No. 4 (2005). __________ Translated from Kibernetika i Sistemnyi Analiz, No. 6, pp. 50–66, November–December 2005.