Search

Austenitic steel Kh20N6G11AM2BF with a nitrogen content of 0.4 wt % exhibits enhanced mechanical properties, high wear, and high resistance to stress-corrosion cracking (SCC) after quenching from rolling heating and after quenching from 1150°C and 15% cold deformation. This shows that it can be used in arctic shipbuilding as a cladding material for hull plates. Strong bonding of Kh20N6G11M2AFB austenitic steel cladding with a nitrogen content of 0.4 wt % with 10N3KhDMBF hull steel is obtained. The shear resistance is registered to be 437–520 MPa. Redistribution of the alloying elements with the formation of a martensitic layer, which is observed at the interface between the cladding layer and the base material, must be taken into account in the final heat treatment considering different processing conditions.

Rapamycin is an increasingly important immunosuppressive drug and reduces restenosis after coronary stenting, but its effects on cardiac contractility are largely unknown. We investigated the acute inotropic effects of rapamycin on isolated human cardiomyocytes. Cardiomyocytes were enzymatically isolated from right atrial appendages obtained during routine coronary artery bypass surgery. Cell morphology was examined by confocal microscopy. Cell contraction was recorded after electrical stimulation. Rapamycin elicited a concentration-dependent decrease in fractional cell shortening ranging from 14.3 ± 2.6% at 10−8M rapamycin to 26.4 ± 4.2% at 10−5M. Rapamycin also caused a concentration-dependent decrease in diastolic cell length. Contractile performance of isolated cardiomyocytes was well preserved, as evidenced by the profound positive inotropic effects of high extracellular calcium concentration and the β-adrenoreceptor agonist isoproterenol. The acute negative inotropic effect of rapamycin on human cardiomyocytes might be due to altered calcium homeostasis through the binding of rapamycin to FKBP12.6 and its regulatory function on the ryanodine receptor, with increased calcium leakage from the sarcoplasmic reticulum.

We solve the problem of identifying the structure of a stochastic process during nonlinear measurements of its state vector in the given finite time interval. The possible variants of practical implementation of the proposed method are analyzed and a numerical example demonstrating its efficiency is considered.

The propagation of the filtration—diffusion combustion front deep in a bulk of titanium powder in a nitrogen medium is studied experimentally. The dependence of the combustion–propagation depth on the height of a fill of titanium powder and the pressure of gaseous nitrogen, the effect of degassing impurities on the limit, and some specific features of combustion are revealed. A model of the process by means of which a formula for estimation of the burning–out depth of the fill is derived is proposed.

Abstract: Numerical results of an experimental study of burning through steel tubes in a water medium by thermite-combustion products are presented. Based on the analysis of experimental data, recommendations on the optimal organization of the process are given, and an empirical formula for calculating the thermite mass necessary for burning through a steel wall is derived.

1.A parameter determining the development of the initiation process with an arbitrary level of heat losses for narrow and broad reaction zones in interacting systems has been Found.2.The possibility of change in the condition of initiation with variation in the heat losses has been demonstrated.3.It has been shown that the development of the initiation of heterogeneous systems is determined by parameters corresponding to a maximum of the heat-liberation rate function. The role of zones of complete combustion in the subsequent development of the transient conditions has been noted.4.The possibility, in principle, of selecting a transient system such as to eliminate extinction at the boundary within the composite charge has been proven.

Myocytes can die by necrosis or by apoptosis and the characteristics of both kinds of cell death are so typical that a differentiation can be made by histological and molecular-biological methods using electron microscopy, dUTP labeling with fluorescence or peroxidase stainig (TUNEL) and the DNA laddering method. However, the problem of quantification of apoptotic cells has not been completely solved because of lack of standardization as well as uncritical use and interpretation of the TUNEL method. Equally, quantification of apoptotic cells is not optimal until now because of three reasons: methodological (overinterpretation of results, no differentiation between myocytes and non-myocytes), experimental (global or regional acute ischemia, chronic conditions such as heart failure or hibernating myocardium), and interpretation (unknown time period for the completion of apoptosis). This problem is reflected in the large differences in incidence of apoptosis reported. Our own data show that in dog myocardium made globally ischemic for 90 min, 8% of the myocytes showed a positive staining for apoptosis (TUNEL method) after 6 h of reperfusion. Despite these results the question of reperfusion injury and the influence of apoptosis still remains open, because it can not be excluded until now that the apoptotic process is initiated during the ischemic period. Studies in hibernating myocardium and chronic heart failure show a similar situation, because of a wide variation of numbers of apoptotic cells and the limited possibility to investigate human tissue. There is no doubt that apoptosis plays an important role in chronic pathophysiological situations such as heart failure and hibernating myocardium but the importance of apoptosis in the acute situation of ischemia/reperfusion still has to be clarified.

Without Abstract:

Without Abstract:

A one-dimensional model of combustion of slightly gaseous porous compositions is considered. Using this model an analysis of the dependence of the combustion characteristics on the basic parameters such as the mass ratio of the “gas-free” and “volatile” components in the starting composition, initial porosity, position of the gas liberation source relative to the reaction front of the “gas-free” component, and degree of sample hermetic sealing is performed for different exothermicity and endothermicity levels of the chemical processes taking place.

Abstract: The role of heat and mass transfer by gas flow at the initial and final stages of the combustion of low-gas-mixture samples is investigated. Transient phenomena are considered. These occur in the course of initiation and decay of the combustion and depend on the combustion wave structure as well as on the conditions of gas mass exchange through the lateral and end surfaces of the sample.

The mathematical model of low-gas condensed systems permits the investigation of a wide range of frontal processes of exothermal conversion of porous condensed compositions with partially gasifying reaction products. However, this model, like the phenomenon itself, is complex, nonlinear, and multiparametric. Lacking the means to obtain an analytical solution in traveling-wave form and establish the limits of its stability, the influence of various determining factors on the limit of stability has been investigated in the present work. This provides a qualitative picture of the influence of the LGC parameters on the stability of steady combustion and permits rational control of the combustion conditions.

Without Abstract:

The effect of isometric and fiber organic and inorganic additives such as chamotte, carbon black, hydrophilic graphite, glass fiber, mullite-siliceous fiber, carboxymethyl cellulose, and cellulose introduced jointly and separately on the penetrability, maximum pore size, size distribution of penetrable pores, and mechanical strength of ceramic materials based on low-melting clay is investigated. It is shown that the pore structure can be controlled by simultaneous introduction of additives of different natures. The materials obtained have a maximum pore size of 1.2–2.9 µm, a gas penetrability of 0.150 µm2, and satisfactory mechanical strength. The materials can be used as ceramic filters.

Infiltration-mediated combustion of a thin porous cylinder in reactive gas was studied by mathematical modeling. Gas reagent is infiltrated through an annular gap left of the side surface. In conditions of instability, the self-sustained propagation of individual cellular spots of exothermic combustion was observed. The structure of cellular waves, their dynamics, and travel direction are defined by such factors as temperature profile, pressure gradients, heat release rate, porous structure, and heat losses. Cellular combustion of Ti powder in dish was also explored experimentally and the results were compared with theoretical predictions.

The article is devoted to the development of the Advanced Driver Assistance Systems (ADAS) for the GAZelle NEXT car. This project is aimed at developing a visual information system for the driver integrated into the windshield racks. The developed system implements the following functions: assistance in maneuvering and parking; Recognition of road signs; Warning the driver about the possibility of a frontal collision; Control of "blind" zones; "Transparent" vision in the windshield racks, widening the field of view, behind them; Visual and sound information about the traffic situation; Control and descent from the lane of the vehicle; Monitoring of the driver's condition; navigation system; All-round review. The scheme of action of sensors of the developed system of visual information of the driver is provided. The moments of systems on a prototype of a vehicle are considered. Possible changes in the interior and dashboard of the car are given. The results of the implementation are aimed at the implementation of the system - improved informing of the driver about the environment and the development of an ergonomic interior for this system within the new Functional Salon of the Gazelle Next vehicle equipped with a visual information system for the driver.