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This paper presents the results of studying the psychological aspects of attitudes to personal security of patients with coronary artery disease (CAD) and heart defects. The research involved 40 patients aged 45 to 81 years (47.5 % male, 52.5 % female): 20 patients with ischemic heart disease with stable angina and 20 patients with acquired heart defects. In the course of the research conducted with the help of the techniques based on subjective scaling, the attitudes to personal security, including the sources of threats, the consequences of the realization of threats and the assessment of efforts on the counteraction to these threats, posing in the author’s theoretical model as the components of the system of the attitudes to personal security, have been studied. The results show that in the patients with heart diseases, the assessments for a variety of threats, the consequences of their realization and the efforts on the counteraction to them are significantly higher, than in the patients with CAD. In general, the estimates for all the parameters in the group of the patients with CAD were closer to the estimates of healthy people, obtained in the previous studies. In the patients with heart defects, characterized by a greater duration and disease severity, the results of the indicators of the attitudes to personal security, in general, are higher and less differentiated. The conclusion is made that the attitudes to personal security as a part of the system of the psychological attitudes in general, can act as a diagnostic criterion and the indicator of the efficiency of the adaptation in cardiovascular diseases and also can be an independent target of the correctional work in a psychological consultation and psychotherapy of the patients with cardiovascular diseases. In the conclusion the recommendations for the experts who are engaged in the psychological help to the patients with cardiovascular diseases in diagnostic and correctional work with the attitudes to personal security are formulated.

Данная статья посвящена обзору психолого-педагогических исследований применения компьютерных игровых технологий в обучении. Проведенный анализ позволяет утверждать, что появился новый тренд положительного отношения к компьютерным игровым технологиям. Предложена классификация применения компьютерных игровых технологий по решаемым обучающим задачам и по уровням обучения.

Weak steady Mach reflections are numerically simulated using unstructured grids by means of either “shock-fitting” or “shock-capturing” techniques. It is shown that shock-fitting allows using coarser meshes than those required by shock-capturing, since the latter needs mesh refinement in the direction normal to the discontinuities, which is not needed using the former approach. The shock-fitted solution is also free from the numerical disturbances that arise along the captured discontinuities and pollute the captured solution in the smooth flowfield region. Finally, the shock-fitting solutions show the presence of a small region next to the Mach stem and the reflected shock downstream of the triple point, characterized by very high gradients.

The problem of transition of planar shock waves over straight wedges in steady flows from regular to Mach reflection and back was numerically studied by the DSMC method for solving the Boltzmann equation and finite difference method with FCT algorithm for solving the Euler equations. It is shown that the transition from regular to Mach reflection takes place in accordance with detachment criterion while the opposite transition occurs at smaller angles. The hysteresis effect was observed at increasing and decreasing shock wave angle.

A preliminary validation study of three DSMC chemistry models, two recent and one standard, is presented. First the 2D geometry and numerical approach used to simulate the shock experiments is verified. Next, 2 different vibrational relaxation models are validated by comparison with data for the M=9.3 case where dissociation is small in the nonequilibrium region of the shock. Finally, the 3 DSMC chemistry model results are compared for the M=13.4 case where nonequilbrium dissociation (in the region where the vibrational temperature is greatly different from the rotational and translational temperature) is important. It is shown that the peak vibrational temperature is very sensitive to vibrational favoring in the chemistry model and that the vibrationally-favored KSS model predicts the measured peak quite well.

Direct simulation Monte Carlo (DSMC) method was applied to numerical study of detonation in an H2/O 2 mixture with detailed chemical kinetics on the basis of effective DSMC molecular chemistry models. The results of the DSMC modeling of an unsteady detonation wave initiated by breakdown of a diaphragm between two channels with different pressures yield the velocity of detonation, which coincides with the ChapmanJouguet velocity. The internal structure of the detonation wave obtained in DSMC simulations is in good qualitative agreement with the detonation-wave structure calculated on the basis of the Zeldovich – von Neumann – Doering (ZND) theory. I. Introduction OLECULAR-LEVEL investigations of gas detonation are important both for applications associated with propagation of detonation waves at small scales and for basic research. The molecular-kinetic description of the gas at the level of the distribution functions of molecular velocities and internal states is usually used for rather rarefied gas flows, in particular, in problems of high-altitude aerothermodynamics of space vehicles [1], though it is also applicable for dense flows. The distribution function is sought as the solution of the integrodifferential Boltzmann kinetic equation, which describes the function evolution due to molecular transfer and collisions. The most effective numerical method for solving the Boltzmann equation is currently the Direct Simulation Monte Carlo (DSMC) method [2]. The conventional treatment of the DSMC method is based on considering the gas flow as a set of 10 5 -10 7 particles (each of them represents a large number of gas molecules) and on the principle of

RANSITIONAL and near-continuum flows are important for numerous promising applications, in particular, in the development of microand nanoelectromechanical systems (MEMS and NEMS) and low-thrust engines for aerospace applications. A more profound understanding of the nature of flows in such engineering systems is an urgent problem of today’s fluid mechanics and also molecular physics [1, 2]. A principally novel aspect of this field is the development of micro-devices capable of performing mechanical work with the use of chemically induced heat release. As the efficiency of conventional devices, such as internal combustion engines, rapidly decreases with a decrease in their size because of higher heat loss, a reasonable direction of MEMS and NEMS evolution seems to be the use of detonation waves at the microscopic scale for accelerating combustion processes and increasing the heat-release rate [3, 4]. This requires better understanding of physical and chemical processes associated with propagation of detonation waves at small scales. There is a significant current effort in this direction; in particular, the beginning of activities aimed at creating a microscopic test facility (shock tube 10 μm in diameter) was announced [4]. Some recent publications also deal with microdetonics – processes that occur during detonation of microscopic amounts of explosives. Interesting results were obtained in experimental research of propagation of detonation waves in capillary tubes (V.I. Manzhalei, Lavrentyev Institute of Hydrodynamics, Siberian Branch, Russian Academy of Sciences, 1992-1999); in particular, Manzhalei found that detonation waves under such conditions can propagate with velocities that are only 0.45-0.6 of the Chapman-Jouguet velocity. It should be noted that propagation of detonation waves in thin capillary tubes is important for explosion safety problems. Numerical simulations can become a really indispensable tool for solving problems of detonation at small scales. There are two different approaches, kinetic and continuum, to the gas flow modeling. In the first approach, the gas is considered at a level of the molecular velocity distribution function which can be determined as the solution of the kinetic Boltzmann equation; in the second approach, the gas or liquid is presented as a continuum whose motion is determined by the laws of conservation of mass, momentum, and energy. Flows whose geometric scales are typical of MEMS are near-continuum or transitional, which necessitates allowance for rarefaction effects, because the mean free path of molecules λ cannot be considered as negligibly small, as compared with the characteristic length scale L of the flow. Though the kinetic approach can be used to describe gas flows in all regimes, its application in practice for modeling a rather dense gas is impossible because of tremendous computational resources needed for that. The most effective numerical method for solving the Boltzmann equation is currently the Direct Simulation Monte Carlo (DSMC) method [5]. It allows computations of steady flows with Knudsen numbers Kn=λ /L=0.001 for twodimensional problems and Kn=0.005 for three-dimensional problems, i.e., up to the continuum flow regime [6, 7]. The DSMC method is well suited for modeling flows with nonequilibrium chemical reactions. Collision models of various chemical processes (vibrational and electron excitation and relaxation, dissociation, recombination, ionization, etc.) can be implemented directly into the collision algorithm. Nevertheless, the DSMC method can be hardly applied to compute unsteady flows because of considerable statistical fluctuations arising if averaging over a sufficiently large time period cannot be performed, which is the case with unsteady flows. Solving such problems is impossible without parallel computational technologies and without using advanced multiprocessor computers. The continuum approach is usually much less expensive, which is a strong argument for using the latter. It is applicable, however, for low Knudsen numbers only. For Knudsen numbers Kn ~ 10 -2 and higher, the continuum approach has

Highly resolved, two-dimensional reactive Navier-Stokes numerical simulations with accurate two-step kinetics were used to study the i nfluence of molecular transport processes on multifront detonation waves. Numerical simulations were performed for a hydrogenoxygen mixture in a flat channel. Simulati ons of viscous detonation in wide channels (the channel width is greater than or commensurable with the detonation cell size) show that the governing effect on the number of tra nsverse waves on the wave front is exerted by the absence or presence (owing to viscos ity and other transport phenomena) of boundary layers on the channel walls rather than by the absolute values of the transport coefficients for a particular mixture. Interaction of transverse waves with boundary layers on the channel walls alters the conditions of wave reflection from the channel walls, as compared with the case of an inviscid detonation wa ve. Different condition of detonation propagation results in a different number of transv erse waves on the leading shock front of the detonation wave. Numerical experiments in narrow channels (the channel width being smaller than the detonation cell size) show that th ere exists a geometric limit of propagation of a viscous detonation wave, i.e., there may be su ch a channel width where a quasi-steady self-sustained detonation mode cannot exist. A near -limit self-sustained marginal detonation wave, a decaying regime of detonations, and a sub-c ritical regime of detonation‐wave propagation are obtained in the present study. Nomenclature a0 = detonation cell width in the Chapman‐Jouguet regime DCJ = detonation velocity in the Chapman‐Jouguet regime H = height of the channel Nx = number of the grid cells in the x direction Ny = number of the grid cells in the y direction p0 = initial pressure of the mixture T = gas temperature, K Tw = channel walls temperature, K u = gas velocity in the x direction, m/s v = gas velocity in the y direction, m/s x = axis along the lower wall of the channel xfr = position of the detonation front along the chann el y = axis upwards, normal to the x axis µ = molecular viscosity

Direct simulation Monte Carlo (DSMC) method was applied to numerical study of detonation in an H2 /O2 mixture with detailed chemical kinetics on the basis of effective DSMC molecular chemistry models. The process of homogeneous adiabatic autoignition of a stoichiometric H2 /O2 mixture diluted by argon was simulated by the DSMC method. The modeling results provide a qualitatively correct description of autoingition process and are in good agreement with the numerical solution of equations of chemical kinetics. The results of the DSMC modeling of an unsteady detonation wave yield the velocity of detonation, which coincides with the Chapman-Jouguet velocity. The internal structure of the detonation wave obtained in the DSMC simulation is in good qualitative agreement with the detonation-wave structure calculated on the basis of the Zeldovich – von Neumann – Doering (ZND) theory.Copyright © 2009 by ASME

The Direct Simulation Monte Carlo (DSMC) method is currently the principal numerical technique for simulation of rarefied nonequilibrium flows at the kinetic level. In the DSMC method, the gas flow is represented by ∼ 10 − 10 model molecules. The process of continuous motion and collisions of molecules at a time step ∆t is divided into two consecutive stages: free-molecular transfer and collisional relaxation. The DSMC method may be treated as a stochastic numerical approach to the solution of the Boltzmann equation. One of the important areas of application of the DSMC method is high-altitude aerothermodynamics of space vehicles. The formation of a high-temperature region behind the bow shock wave is associated with the translational-rotational nonequilibrium and the excitation of vibrational molecular modes, which have significant impact on spacecraft aerothermodynamics at altitudes below 90 km. This necessitates modeling of energy exchange between translational, rotational, and vibrational modes of molecules, and raises requirements to accuracy and efficiency of energy transfer models used in the DSMC method. A simple Larsen-Borgnakke model has been successfully used for a long time to model the rotationtranslation (RT) and vibration-translation (VT) energy exchange in DSMC. In this model, post-collisional energies are sampled according to the local Boltzmann distribution. The Larsen-Borgnakke model is constructed in such a way that it allows one to exactly reproduce the solutions of relaxation equations for the mean rotational and vibrational energies in the homogeneous case. 4 The temperature dependences of rotational and vibrational relaxation times are well known for many diatomic molecules, which allows one to determine temperature-dependent probabilities of the corresponding collisional processes. The main advantages of this model over more complicated and accurate models are the possibility of using it for multispecies gas mixtures consisting of molecules of different type (including polyatomic molecules), simplicity of implementation, and numerical efficiency. Exchange of vibrational energy between the colliding molecules (VV exchange) is a process that plays an important role in aerothermodynamics of space vehicles, gas-dynamic lasers, gas discharge, etc. This process has been extensively studied theoretically for several decades (see, e.g., Refs. 5-9). There are several papers where VV transitions for diatomic molecules were modeled by the DSMC method. The model is worth noting: both VT exchange and VV exchange were modeled, and multiquantum VT and VV transitions were considered on the basis of the theoretical models. 6 One should also note the paper where VT and VV transitions for SHO were considered, the paper where the near-resonant VV exchange for anharmonic oscillators was studied (it was also noted there that the model does not satisfy the detailed balance principle), and the simple statistical model with single-quantum VT transitions and VV

Results of numerical simulations of high-altitude aerothermodynamics of the EXPERT reentry capsule along its descent trajectory are presented. Aerodynamic characteristics for different angles of attack and rolling of the capsule at altitude of 150 down to 20 km are studied. An engineering local bridging method is used in computations. The uncertainty of the engineering method in the transitional regime is determined by comparisons with results obtained by DSMC simulations. I. Introduction During disorbiting, the spacecraft experiences the influence of the atmosphere with significantly varying parameters. To estimate the aerodynamic loads and to predict the landing area, one should know, already at the stage of design, the coefficients of aerodynamic forces and moments of the spacecraft for varying temperature, density, flight velocity, and angles of attack and sideslip for numerous possible descent trajectories. Thousands of various variants have to be computed. At the beginning of descent, at high altitudes where the gas is strongly rarefied, numerical simulations do not involve many difficulties, because theoretical approaches have been developed for simple shapes and the Test Particle Monte Carlo method can be readily used for more complicated shapes. On the other hand, various engineering approaches have been developed for calculating aerodynamic characteristics of various bodies at the final segment of the descent trajectory, in the continuum regime, which are fairly effective. The main problem is the analysis of spacecraft aerodynamics in the transitional regimes between the free-molecular and continuum regimes. The Navier-Stokes equations yield, strictly speaking, incorrect results in the transitional regime and require special modifications for taking into account flow slipping. The Direct Simulation Monte Carlo (DSMC) method provides rather accurate values of aerodynamic characteristics with allowance for physical and chemical processes but requires large amounts of computer memory and performance. Application of the software based on the DSMC method is unreasonably expensive at the initial stage of spacecraft design and trajectory analysis. A possible solution of this problem is the approximate engineering methods. These methods allow calculating aerodynamic characteristics of bodies of arbitrary geometry for multiple variants of free-stream parameters within a reasonable time and then to refine the results at the most important segments of the flight trajectory by the DSMC method. The use of fast approximate engineering methods is the most acceptable approach to solving problems of spacecraft aerodynamics at the stage of conceptual design. The present paper describes the computations of aerodynamics of the EXPERT capsule by an engineering local bridging method at altitudes of 150 down to 20 km with flow parameters corresponding to the expected descent trajectory. The results in the transitional regime are refined by the DSMC method. The errors of the engineering method are studied in detail, and the contribution of various elements of the EXPERT capsule to aerodynamic characteristics is analyzed. II. EXPERT geometry The KHEOPS configuration (Fig. 1) is a blunted pyramidal shape featuring four flaps. The computational model was constructed by the RuSat software system. The total number of panels is approximately 36 thousand. The nose is made in the form of an ellipse with a misalignment of 0.9165. The local radius of the nose part is 0.6 m. The ellipse-cone junction is described by a clothoid. The conical body has a cone angle of 12.5°. The cone is truncated by planes at an angle of 8.35° to the axis of symmetry. Four control flaps are deflected by 20 °.

A novel approach to statistical simulation of high-temperature nonequilibrium chemical reactions is described. Vibrationally speciflc dissociation cross sections are sought solving an integral equation whose right side contains a two-temperature reaction rate constant. An approximate stable solution of this equation is found numerically by Tikhonov regularization method. The class of functions to which the solution belongs is deflned on the basis of physical concepts of the form of the sought cross sections as functions of energy. The approach is illustrated by an example of the model of high-temperature dissociation of nitrogen. All stages of model implementation are considered in detail, namely, the mathematical basis, analysis of the model by comparisons with conventional models both at the level of cross sections and at the level of macroscopic reaction rates, and particular applications to computations of near-continuum reacting ∞ows by the Direct Simulation Monte Carlo method.

The use of two modications of the local bridging method for approximate estimates of aerodynamic characteristics of complex-shaped reentry vehicles in a wide range of Knudsen numbers is presented. Additional computations by the DSMC method are used to estimate the accuracy of these engineering methods. he orbit of advanced space vehicles lies at altitudes of about 300-400 km. During their reentry to the Earth, the vehicles rst experience the action of the free-molecular o w, then enter the transitional regime, and nally , beginning from an altitude of 80 km, descend in the continuum o w. For successful reentry of the vehicle to the Earth, it is necessary to know the behavior of its aerodynamic characteristics in all o w regimes. Computation of aerodynamic characteristics of reentry vehicles in the free-molecular o w does not involve many diculties because theoretical approaches have been developed for simple shapes and the Test Particle Monte Carlo method can be readily used for more complicated shapes. Methods for computing aerodynamic characteristics in the continuum o w have also been adequately developed. The study of aerodynamic characteristics in the transitional o w regime (0:001 < Kn < 10) is a rather complicated problem. The Navier-Stokes equations fairly suitable in the continuum medium, yield, strictly speaking, incorrect results in the transitional regime and require special modications for taking into account o w slipping. The Direct Statistical Monte Carlo (DSMC) method provides rather accurate values of aerodynamic characteristics with allowance for physical and chemical processes but requires large amounts of computer memory and performance, which hinders the use of this method. There are several software systems that allow simulation of 3D-aerodynamics of reentry vehicles in the transitional regime (e.g., SMILE, DAC), but their application at the initial stage of spacecraft design and trajectory analysis is unreasonably expensive because it is necessary to compute a large number of variants for dieren t angles of attack and sideslip and for dieren t o w parameters. The approach for solving this problem is to use approximate engineering methods, which oer acceptable accuracy with a short computation time. For instance, the existing aerodynamic software system Ramses 1 includes an engineering method based on local bridging interpolation between the free-molecular and continuum o w regimes to obtain of local aerodynamic characteristics in the transitional regime. Accuracy evaluation of engineering methods is dicult because of the lack of experimental data on aerodynamic characteristics of modern spacecraft in the transitional regime. One possible way is a comparison with the complicated but accurate DSMC method. The aerodynamic characteristics of promising reentry capsules KHEOPS and Clipper in free-molecular and transitional regimes were examined in the present paper.

The use of two modifications of the local bridging method for approximate estimates of aerodynamic characteristics of complex -shaped reentry vehicles in a wide range of Knudsen numbers is presented . Additional computations by the DSMC method are used to estimate the accuracy of these engineering methods.

In studying the detonation phenomenon in gas mixtures, much attention is traditionally paid to investigation of the multifront (cellular) structure of a self-sustained unsteady detonation wave (DW) propagating in a mixture at rest, determination of the critical conditions of detonation initiation (critical value of the initiation energy), and marginal regimes of DW propagation.

Numerical simulations have been performed to study regular and Mach reflections of oblique shock waves (SW) in a steady supersonic flow of a homogeneous combustible hydrogen-oxygen gas mixture and different inflow Mach numbers Min. The dynamics of the compressible medium was described by two-dimensional unsteady Euler equations. Chemical transformations in the gas mixture were described by a two-stage reaction model. The resultant hyperbolic system of equations was solved numerically using the finite-volume scheme with the fourth-order MUSCL TVD reconstruction and the advanced HLLC algorithm for an approximate solution of the Riemann problem. Integration in time was performed with a second-order accuracy by using recently developed, additive semi-implicit Runge-Kutta methods. It was found that, as for nonreacting SW, there is a dual solution domain, where the existence of both regular reflection (RR) and Mach reflection (MR) is possible under identical flow parameters and geometry. In the case of the MR, the Mach stem (MS) is a section of the front of an overdriven stationary detonation wave (DW). A hysteresis phenomenon was obtained for a varied wedge angle θ.The dependence of the Mach stem height on the value of θ was found. It was showed ∗ Senior Research Scientist, Computational Aerodynamics Lab. † Senior Research Scientist, Computational Aerodynamics Lab. ‡ Professor, Head, Computational Aerodynamics Lab. Associate Fellow AIAA. E-mail: ivanov@itam.nsc.ru that for some values of Min there may exist a standing MS with a system of unsteady transverse waves on its front. The flow structure behind the Mach stem is similar to the flow structure behind the front of a multifront (cellular) freely propagating DW. Despite the motion of the transverse shocks along the MS and periodic changes in the stem shape, MS, on the average, is a standing wave that slightly oscillates near some equilibrium point. The effect of an existence of strong transverse waves on the MS front to steadiness of Mach reflection was investigated. The present study showed that the Mach stem height for the case of a chemically reacting mixture is greater than that for an inert mixture. For a model combustible mixture with variable amount of heat release, the dependence of the MS height on chemical reaction heat was found. The present study showed that certain types of local perturbations of the free-stream flow might initiate the transition from RR to MR in the dual-solution domain.

* Research scientist, Theoretical and Applied Optics Department. † Research scientist, Fundamental and Experimental Aerodynamics Department. ‡ Senior research scientist, Physical Instrumentation and Sensing Department. § Scientific director, Office National d’Etudes et de Recherches Aerospatiales. ¶ Senior research scientist, Institute of Theoretical and Applied Mechanics. # Professor, Institute of Theoretical and Applied Mechanics. Associate fellow. INTRODUCTION

A hypersonic monoatomic gas (argon) flow around a hollow cylinder flare was numerically simulated for low-to-moderate Reynolds numbers. A shock wave induced by the flare causes the formation of a separation region, and flow rarefaction near the leading edge affects the separation extent. The continuum (Navier–Stokes equations) and kinetic (the DSMC method) approaches were used to study the influence of the Mach number and wall-to-freestream temperature ratio on the flow structure and separation. To take into account rarefaction effects, slip boundary conditions are used for the Navier–Stokes solver.

The influence of relaxation associated with the excitation of vibrational degrees of freedom and chemical reactions, and flow rarefaction on the shock wave reflection phenomena in steady flows is studied in the present paper. The main attention is paid to the impact of the change in the relaxation length, which occurs due to changing Mach number, on the angle of transition from regular to Mach reflection and on the Mach stem height. The Direct Simulation Monte Carlo method is used in the computations. The computational results are compared with predictions obtained using an analytical model that takes into account the change in specific heat ratio behind the shock wave. A substantial effect of relaxation and rarefaction on regular and Mach reflections and on the RR—»MR transition angle is shown.

An impact of vibrational and chemical relaxation and flow rarefaction on the transition from regular to Mach reflection in steady supersonic flows is examined numerically with the direct simulation Monte Carlo method. Wedge-generated shock reflection in N-Nj gas is studied for M — 7.5 and Kn = 3.5 • 1CT and 9.0 • 1CT at fixed and moving wedges. Three different models of molecular collisions were considered, the first allows translationrotation energy exchanges only, the second also takes account of molecular vibrations, and the third is the general case with translation-rotation-vibration exchanges and dissociation reactions. A significant influence of real gas effects both on regular and Mach reflections is shown, and a delay of regular-to-Mach reflection transition is observed.

A detonation wave propagation along a two-dimensional 1-mm-width channel in hydrogenoxygen stoichiometric mixture has been simulated by Direct Simulation Monte Carlo method. A detailed chemical kinetic mechanism for 6 species has been implemented and all the chemical reactions have been modeled at a level of molecular collisions. Unsupported Chapman-Jouguet detonation has been observed with condition of specular reflection of molecules on the side walls. When friction and heat conduction on the side walls are taken into account through diffuse reflection conditions a detonation wave is significantly weaker and its propagation velocity is lower than predicted by the Chapman-Jouguet theory.