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Features of the simulation of the thermodynamic and gasdynamic processes occurring in devices for reducing the noise level of a shot from a gun were considered. A simulation of large vortices in the nonstationary turbulent flow of powder gases in a muzzle noise reduction device with a silencer representing a shaped channel with several chambers, whose volumes decrease in the direction to the silencer outlet, has been performed. Results of qualitative and quantitative investigations of the initiation, development, and damping of the shock waves in the flow of powder gases, formed as a result of the firing of a shot made from a signal gun, are presented.

The impetus for this article was provided by Ing. I. M. Pautkin and Dr. D. N. Matveev (for which I am grateful to them) the following works

Possibilities for using general-purpose graphics processing units to simulate compressible gas flows are discussed. Consideration is given to different schemes of computation of flows through the faces of the flow control volume and to the features of their implementation on graphics processing units. A solution of a number of model problems of gas dynamics on graphics processing units is presented and consideration is given to approaches to optimization of the program code connected with the use of different types of memory. A comparison is made between the rates of counting on a graphics processing unit and a central processor using grids having different resolution capabilities and various difference schemes of computation of flows.

Background.The prevalence of various allergic diseases has increased worldwide in recent decades. Allergy diagnosis in children should be economically optimal and as sparing as possible, while ensuring the high quality of medical care.Objective.The aim of the study is to develop optimal algorithms for analysis of sensitization profile in children with allergy family history, or suspected allergy, or atopy phenotype.Methods.Complete examination of 153 children aged from 1 to 17 years 11 months was performed. Children were divided in 4 groups according to the presence and characteristics of complaints, the presence of allergic disease. Sensitization was determined via the “gold standard” of allergy diagnosis — the ImmunoCap method (Phadia, Sweden), and the results of skin testing.Results.97 (63.4%) children have shown sensitization to various allergens. We have revealed seasonal manifestation of allergy in children to various allergens: Fagales in 89-92% of cases, grasses in 68-72% of cases, weeds in 39-57% of cases. Complaints of all-year manifestations of allergic rhinitis were revealed in 24% of cases to cat dandruff, complaints of coughing and/or bronchospasm — in 100% of cases to birch pollen and in 35% of cases to house dust. The sensitization analysis has revealed strong correlations with confirmed statistical significance between pollen allergen sensitization classes in groups of different plants.Conclusion.Optimal algorithms for sensitization diagnosis in children living in Moscow agglomeration were developed according to the obtained results and revealed correlations.

A numerical simulation of a nonstationary flow of a gas containing inert particle in a shock tube has been perfumed on the basis of the model of mutually penetrating continua, in which the gaseous and dispersed phases are defined by sets of mass, momentum, and energy conservation equations and the equation for the evolution of the dispersed-phase volume fraction. The main equations are hyperbolic, and they are solved using the Godunov-type method of increased accuracy. The shock-wave structure of the gas flow in the working section of the shock tube and the space and time dependences of this flow were determined. The numerical-simulation results are compared with available experimental and calculation data.

A numerical simulation of the flow induced by rotation of the ducted fan blades of a quadcopter is carried out using the vortex-resolving approach that assumes solution of the full Navier–Stokes equations. Based on the numerical simulation results, the aerodynamic characteristics of the ducted fan are determined in various flight modes with asymmetric airflow over the surface swept by the propeller. In the problem formulation, various angles of the ducted fan rotation plane deviation from the vertical were considered for various flight modes of a multicopter type aircraft as well as characteristics of the non-perturbing incident air flow.

The influence of the geometric and regime parameters of a resonance infrared jet-edge generator on the formation, in its resonance tube, of a sound field with a predominant discrete tone at the fundamental frequency of the generator resonant cavity was investigated. A parametric investigation of the self-sustained oscillation processes arising in the resonance tube of the generator as a result of the interaction of a subsonic gas jet and a supersonic one with its resonant cavity has been performed. The nonstationary structure of the gas flow inside this cavity, characteristic of the self-sustained oscillation interaction of a gas jet with an obstacle, is discussed. Prominence is given to the study of the pattern of the gas flow inside the resonant cavity and the amplitude-frequency characteristics of the wave process in it. Recommendations for designing a resonance infrasound jet-edge generator with regard for its use in actual practice are given.

The choice of non-drug methods for the treatment of systemic scleroderma is currently very limited. Several studies show that extracorporeal photochemotherapy can improve kidney and lung function and reduce skin fibrosis in patients with systemic scleroderma. We studied the dynamics of clinical and laboratory parameters in patients with systemic scleroderma with an assessment before and after 12 months against the background of complex treatment, which included programmed extracorporeal photochemotherapy. Indications for inclusion in the study was the ineffectiveness of standard therapy with glucocorticoids and cytostatics or the impossibility of their use, as well as signs of an unfavorable prognosis of the disease: diffuse form, high skin count (14), rapid progression with a significant initial decrease in the glomerular filtration rate, forced vital capacity, high immunological activity (high titer of antinuclear factor and positivity for antibodies to Scl-70). When evaluating the results of complex treatment, a good clinical effect was observed in all patients: the induration of the skin decreased, the functionality of the lungs and kidneys increased. A significant decrease in the disease activity index was noted. These positive changes were the basis for a decrease in the daily dose of glucocorticoids. Significantly significant changes were observed in a decrease in the immunological activity of the disease: levels of C-reactive protein, erythrocyte sedimentation rate and immunoglobulin G, antinuclear factor titer and all types of circulating immune complexes. The results of our study confirm the data of other studies that demonstrated the positive effect of extracorporeal photochemotherapy as a component of the complex treatment of systemic scleroderma.

The results of complex treatment with the programmed procedures of extracorporeal photopheresis and methotrexate in patients with psoriatic arthritis for 12 months are presented. It has been established that program extracorporeal photopheresis in combination with basic therapy with methotrexate in patients with psoriatic arthritis have a significant effect on the relief of articular syndrome (reduction of morning stiffness, pain intensity, joint swelling). It was revealed that the inclusion of programmed extracorporeal photopheresis and methotrexate in the complex treatment of psoriatic arthritis reduces the level of circulating low molecular weight, medium molecular weight and high molecular weight immune complexes and in most cases leads to clinical and immunological remission. This is confirmed by a decrease in complaints of the severity of articular syndrome and a decrease in the clinical and laboratory activity of the disease (a significant decrease in the level of C-reactive protein, erythrocyte sedimentation rate). A scheme has been developed for the programmed use of extracorporeal photopheresis procedures in the complex treatment of psoriatic arthritis, which consists of 2 procedures every other day with an interval of 2,5-3 months for 12 months. Combined therapy with the programmed application of extracorporeal photopheresis procedures and methotrexate prolongs the period of disease remission and can be recommended for patients with psoriatic arthritis with high activity, insufficient effect of basic therapy and intolerance to higher doses of immunosuppressive drugs.

Problems on the development of mathematical models for control of the technological processes of producing powders of metals from their melts and for optimization of these processes were considered. A numerical simulation of the solidification of melt droplets in a turbulent cold-gas jet has been performed with the use of a complex mathematical model, and results of this simulation were used for estimating the influence of different factors on the flying of a melt droplet in a gas flow until it is solidified.

The design of a subsonic jet-edge rod generator of the Hartmann-type oscillator and a scheme of measuring its acoustic parameters are presented. In this generator, unlike the Hartmann oscillator, not a cylindrical gas jet but an annular gas jet, moving along the thin cylindrical rod positioned at the axis of the generator nozzle, is used. A parametric investigation of the gasdynamic and acoustic processes arising in the tubular cavity of such a generator as a result of the interaction of a subsonic gas jet with this cavity has been performed with consideration for the nonstationary structure of the gas flow in the generator cavity. Recommendations on the choice of the design of a jet-edge rod generator of acoustic radiation with regard for its practical application are given.

Numerical modeling of the underwater outflow of a supersonic gas jet in a three-dimensional non-stationary formulation is carried out using an eddy-resolving approach based on a combination of RANS-LES turbulence modeling methods. The calculation of the interaction of a gaseous medium with a liquid is carried out using the VOF multi-phase model, the forces of surface tension and the compressibility of the liquid are taken into account. As a result of calculations, an unsteady pattern of the formation of a supersonic jet and a gas cavity in a liquid is obtained, the shock-wave structure of the flow is visualized, and pressure fluctuations in the liquid are estimated. The results of calculations are compared with the data of experimental high-speed photography.

A simulation of a high-temperature air flow in a nozzle with a nonstationary local power supply has been performed. The thermodynamic processes in this flow were simulated using an approximate model of equilibrium air thermodynamics. Results of a numerical simulation of one-dimensional flows in nozzles with a moving powersupply zone, used in alternating-current plasma generators, are presented. On the basis of the numerical-simulation data obtained, the qualitative patterns of the gasdynamic and thermal processes proceeding in such a nozzle with a nonstationary power supply were analyzed. The results of calculations performed on the basis of the ideal-gas and real-gas models with regard for the physicochemical processes occurring in a real gas at a high temperature were compared.

Interest in the development of models and methods focused on the mechanisms of noise generation in jet flows is due to strict noise requirements produced by various industrial devices, as well as the possibilities of using sound in engineering and technological processes. The tools of physical and computational modeling of gas dynamics and aero-acoustics problems are considered, and noise sources and mechanisms of noise generation in supersonic jet flows are discussed. The physical pattern of the flow in free supersonic under-expanded jets is discussed on the basis of experimental and numerical data, as well as the flow structure arising from the interaction of a supersonic under-expanded jet with a cylindrical cavity. The influence of the nozzle pressure ratio and cavity depth on the sound pressure level, amplitude and frequency characteristics of the flow parameters is studied.

The interaction of solid particles with vortex structures was investigated, and the scattering of such particles by a combined vortex was numerically simulated using the Euler–Lagrange approach. The concentration distributions of particles in the region of a gas flow occupied by a vortex at different instants of time have been obtained. The dependence of the time for which these particles escape from the central zone of the vortex on their size was determined. The results obtained can be used for increasing the efficiency of measurement of the parameters of the disperse phase in a fluid flow by optical methods.

According to WHO, burns rank third place among other injuries, and in some countries, the second, after traffic injuries. One of the promising tools for treating burn wounds is the use of lyophilized xenograft skin substrate. The purpose of this work was to determine the morphometric parameters of the affected by burns area of the skin in the dynamics after an experimental thermal trauma and in the case of correction by crushed lyophilized xenograft skin substrate. Burning of third degree on the shaved skin of the back of the guinea pig was applied to the vapor under general anesthetic. Morphometrically, at 7, 14, and 21 days of the experiment, the thickness of the epidermis (thin skin without a layer of scales), the number of fibroblast cells per unit area, the outer and inner diameter of the capillaries were determined in the boundary and central areas of the wound. Morphometric studies were carried out using programs VideoTest-5.0, KAAPA Image Base and Microsoft Exсel on a personal computer. Statistical processing of the obtained quantitative data was carried out using methods of variation statistics with the determination of the mean arithmetic and its error (M±m), Student’s criterion (t) and reliability index (p). Differences are considered valid at р≤0.05. It has been established that already in the 7 day of the experiment, under conditions of wound closure by xenograft skin substrate marked a significant thickening of the epidermis on the periphery of the wound appear. Activation of the process of boundary epithelization contributes to the renewal of components of the microcirculatory bed, the formation of granulation tissue. It was found that on the 14 day of application of the corrective factor in the peripheral zone of the wound, the number of cells of the fibroblast row and the mean value of the thickness of the epidermis reach their peak value, significantly (p

According to the experimental study on Vietnamese pigs after implantation of a polypropylene mesh with PRF membrane into retromuscular space, the results of ultrastructural changes in the cells of muscular aponeurotic layer of abdominal wall were presented. It was proved that on the 14th day of the experiment, inflammatory changes in tissues were expressed significantly less than in cases of the isolated implantation of the polypropylene mesh without PRF membrane. Activation of fibroblasts and signs of fiber structures development around the mesh material increased. In the late experimental period (28 days), at the microscopic and electron-microscopic levels the minor manifestations of inflammatory reaction, improved microcirculation in the area of implantation of the mesh with PRF membrane were found that in turn contributed to the increased activity of fibroblasts and development of collagen fibers around the mesh material. The use of PRF plasma membranes stimulated an active development of new capillaries, improved blood flow, accelerated metabolic processes in tissues, and suddenly increased development of collagen, hyaluronic acid that in turn created favourable environment for a complete integration of the polypropylene mesh into the muscular aponeurotic layer of anterior abdominal wall tissue.

The lack of the ability to determine the individual standard angle characteristics of the position of the teeth and the technical provision of their control often does not lead to the expected result and in each case requires individualization, the vision of which is based, as a rule, on the experience and intuition of the doctor. In order to solve such a situation, in addition to improving the positioning protocols of the non-removable equipment, the physician should be able to clearly identify the individual angular characteristics of the tooth-jaw system. The purpose of the study – by studying computer tomography and cephalometric indices and conducting direct stepwise regression analysis to develop in Ukrainian adolescents with orthognathic bite mathematical models of individual angular positions of teeth. Using the Veraviewepocs 3D device, Morita (Japan) at 38 young men (aged from 17 to 21) and 55 young women (aged from 16 to 20 years) with normal occlusion close to orthognathic bite received and analyzed dental tomograms and lateral teleroentgenograms. Cephalometric points and measurements were performed according to recommendations of A. M. Schwarz, J. McNamara, W. B. Downs, R. A. Holdway, G. P. F. Schmuth, C. C. Steiner and C. H. Tweed. Anatomical points were determined taking into account the recommendations of A. E. Athanasiou and S. I. Doroshenko and Y. A. Kulginsky. The simulation of CT indexes describing the position of individual teeth relative to each other, to the bone cranial structures and the profile of adolescents with orthognathic bite, depending on the metric characteristics of the skull, which are usually unchanged during surgical and orthodontic treatment, as well as the width, lengths, angles and positions of the upper and lower jaws that may be altered by orthodontic surgery done. The statistical processing of the obtained results was carried out in the license package “Statistica 6.0” using a direct stepwise regression analysis. It was found that in young men of 40 possible models, 23 were constructed with a determination coefficient R2 of 0.557 to 0.832, while in young women, only 8 models with a determination coefficient R2 of 0.581 to 0.832. Moreover, in the young men – of 10 possible 9 models of vestibular-tongue inclination of corresponding teeth (R2 from 0.557 to 0.832) were constructed; out of 10 possible 5 models of mesio-distal inclination of corresponding teeth (R2 from 0.558 to 0.769) constructed; of the possible 14 constructed 6 models of rotation of the corresponding teeth (R2 from 0.579 to 0.737); and in young women - there are only 5 models of vestibular-tongue inclination of the corresponding teeth (R2 from 0.603 to 0.665). In addition, in both young men and young women, models of the size of the inter-incision angle (R2 0.748 in young men and 0.581 in young women) were constructed, the magnitude of the angle of inclination of the lower canine in the jet plane (R2 respectively 0.729 and 0.793), and the magnitude of the inclination of the closure planes relative to the palatal plane (R2 respectively 0.808 and 0.832). In the analysis it was found that in young men, most frequently models included - indicator WITS (7.0%); angle GL_SNPOG (5.4%); distance S_E, angle ММ, angle NSBA (by 4.7%); angle AB_NPOG, angle N_POG_, distance N_SE, coefficient N_SP_SP, angle P_OR_N (by 3.9%). In young women, most frequently models included – angle N_POG_ (14.3%); angle AB_NPOG (10.2%); indicator WITS (8.2%); angle ММ, angle ANB, length of the branch of the mandible R_ASC (by 6.1%). Thus, in the work with the help of the method of step-by-step regression with inclusion, among Ukrainian adolescence, on the basis of peculiarities of computer-tomographic and teleroentgenography indices, reliable models of computer-tomographic individual linear angular characteristics of the position of teeth necessary for constructing the correct three-dimensional geometry of dental arches are developed and analyzed.

The ultrastructural changes of the tissues of musculo-aponeurotic layer of anterior abdominal wall after implantation of the “lightweight” and “heavyweight” polypropylene meshes into the retrometallic space were studied in the experiment. Significant differences of the tissue reactions at different periods of the experiment on the implanted material were evidenced. The presence of a moderately pronounced inflammatory tissue reaction was noticed on the 14th day of the study in the area of the implantation of the “lightweight” polypropylene mesh compared to the “heavyweight” one: the inflammatory response included acute manifestations of aseptic inflammation with a significant tissue response. On the 28th day of the experiment, in cases of implantation of the “lightweight” mesh, the stabilization of tissue reaction to the implant with reduction of inflammatory changes was observed, as evidenced by a significantly smaller number of leukocyte infiltration sites, a significant improvement in vascularization and development of collagen fibres around the mesh material with fibroblasts, which was not observed in the area of implantation of the “heavyweight” polypropylene mesh. The conducted morphological and ultrastructural studies have prioritized the use of “lightweight” meshes when choosing material to perform allohernioplasty.

Background. To date, numerous clinical observations and experimental data have proven that there is practically no such organ that would not be subjected to toxic effects of alcohol. Purpose of the work was to determine the dynamics of changes in the metric indices of the submandibular glands’ resistive link of the haemomicrovascular bed of the rats in chronic ethanol intoxication. Methods. The work was performed on 45 white, non-breeding rats. 5 animals were an intact group, which was washed out 4 times a day with isotonic sodium chloride solution, and 40 - experimental, which was injected intrastomach 1 times a day with 12 mg / kg 400 ethanol (in terms of pure alcohol). Animals were withdrawn from the experiment at 5, 9, 12 and 30 days by overdose of thiopental anesthesia (25 mg / kg). Sections of the submandibular glands were enclosed in epon-812 according to the generally accepted method. The mean values of the outer diameter and diameter of the arterioles lumen were determined using a microscope with a digital microphocamera Biorex 3 with an adapted for data research program. Results. In the morphometric study it was found that on the fifth day after ethanol introduction, the mean values of the outer diameter of the arterioles decreased significantly by 15.8%, compared with the control group, and amounted to 15.28 ± 0.06 μm. Also, the diameter of the arteriol lumen was reduced by 53.5%, compared with the control group (p, Реферат. Многочисленными клиническими наблюдениями и экспериментальными данными доказано, что практически нет такого органа, который не поддавался бы токсическому действию алкоголя. Безусловно, существенное патогенное влияние алкоголь оказывает именно на систему пищеварения, так как ей приходится первой вступать в контакт с этанолом. Целью работы было установить динамику изменений метрических показателей резистивной звена гемомикроциркуляторного русла поднижнечелюстных желез крыс в норме и при хронической интоксикации этанолом.В работе проведено морфометрическое исследование, которое установило, что хроническая интоксикация этанолом влияет на резистивное звено гемомикроциркуляторного русла долек поднижнечелюстной слюнной железы. На ранних сроках наблюдения определяется спазм сосудов, что подтверждается увеличением толщины сосудистой стенки на 41,8%. На девятые сутки наблюдается дилатация, которая проявляется достоверным увеличением диаметра внешнего и просвета, и уменьшением толщины сосудистой стенки. Нормализация показателей к тридцатым суткам не определяется., Реферат. Численними клінічними спостереженнями і експериментальними даними доведено, що практично немає такого органу, який не піддавався би токсичній дії алкоголю. Безумовно, істотний патогенний вплив алкоголь робить саме на систему травлення, так як їй доводиться першій вступати в контакт з етанолом. У порожнині рота етанол пригнічує секрецію і підвищує в'язкість слини. Відомі дані про токсичний вплив етанолу на внутрішні слизові оболонки органів, що викликає їх опік і порушення диференціювання. Значний вплив на функціонування органів має стан ланок гемомікроциркуляторного русла, особливо резистивної, яка забезпечує надходження крові до паренхіматозних елементів та адекватну оксигенацію. В деяких роботах встановлено, що при експериментальній гіпосалівації, як ендогенного, так і екзогенного генезу відбувається стійке звуження резистивної ланки гемомікроциркуляторного русла. Застосування морфометричного методу дозволяє об’єктивно оцінити зміни в структурних елементах органів після дії різних ендогенних та екзогенних чинників. Метою роботи було встановити динаміку змін метричних показників резистивної ланки гемомікроциркуляторного русла піднижньощелепних залоз щурів в нормі та при хронічній інтоксикації етанолом. У роботі проведене морфометричне дослідження, яке встановило, що хронічна інтоксикація етанолом впливає на резистивну ланку гемомікроциркуляторного русла часточок піднижньощелепної слинної залози. На ранніх термінах спостереження визначається спазм судин, що підтверджується збільшенням товщини судинної стінки на 41,8 %. На девʼяту добу спостерігається дилатація, яка проявляється достовірним збільшенням діаметру зовнішнього і діаметру просвіту, та зменшенням товщини судинної стінки. Нормалізація показників до тридцятої доби не визначається.

The formation of regions with a higher concentration of solid particles in the completely developed turbulent flow in a channel with impermeable walls was investigated. A gas flow was simulated on the basis of nonstationary three-dimensional Navier–Stokes equations. The discrete-trajectory approach was used for simulation of the movement of particles. On the basis of the data of a direct numerical simulation, the distributions of the average and pulsating characteristics of the flow in the channel and the concentration distribution of the dispersed phase in it were determined. It was established that the formation of regions with a higher concentration of solid particles in the channel is due to the instantaneous redistribution of vorticity near its walls. The numerical-simulation data obtained are in qualitative and quantitative agreement with the corresponding results of physical and computational experiments.

In the article the function and the scale for the entropy evaluation of the current state of sensors quality in the technical system which fits the requirements of universality and maximal independency from the human factor are offered. It is highlighted that the available methods of the determination of the quality of the technical systems have essential flaws which consist in both subjectivism because the dominant role in the evaluation belongs to experts and legitimacy of providing them properties of universality which was proved by nobody. The offered function of the quality evaluation, the parameter of which is the quantity of own information of the explored sensor, provides the declared universality approach according to the principles of the information theory. The conformity to all requirements for the functions of the evaluation of the quality: continuity, monotonicity and smoothness over the whole range of definition regardless of the probability distribution function, which is measured by the random value sensor was proved. The conformity to all requirements for the functions of the quality evaluation: continuity, monotonicity and smoothness over the whole range of definition regardless of the probability distribution function, which is measured by the random value sensor is proved. The proposed scale of the entropy evaluation of the quality fits to standard settings of the diagnostic of the technical systems and has three subranges which determine the state of the sensors: good state, up state, and down state. Unlike the existing psychophysical scales the offered scale has dynamic range of the evaluation so the limits of the subranges will automatically change depending on the regulatory and technical requirements for the state of the explored sensor. Such approach provides adaptation of the scale to specific requirements which gives a chance to evaluate the qualitative state of the object more reliably. The results of modeling of the qualitative state of the sensor are given. The possible practical application of the offered function and scale is usage in the systems of monitoring and diagnostic for determination of the current qualitative state of the explored technical system.

A numerical simulation of a supersonic two-dimensional gas flow into which a gas jet is injected from the surface of a fl at plate along the normal to it has been performed. The calculations were carried out using the Reynolds-averaged Navier–Stokes equations closed by the SST model of turbulence. The influence of the pressure ratio of the jet on the structure of the flow formed as a result of its injection into the supersonic crossflow, the angle of inclination of the head shock wave, the length of the separation zone, and the depth of penetration of the jet into the main flow were determined. The results of calculations performed for different Mach numbers of the main flow and different pressure ratios of the injected jet were compared with the corresponding results of a physical experiment. The data obtained can be used for optimization of the mixing of the injected jet with the main supersonic crossflow.

The transverse injection of a pulsed jet into a supersonic flow for thrust vectoring in solid rocket motors is investigated. The gas flow through the injection nozzle is controlled by a piston which performs reciprocating motion. Reynolds-averaged Navier–Stokes equations and the (k–e) turbulence model equations are discretized using the finite volume method and moving grids. The pressure distributions on the plate surface obtained using various approaches to the description of the flow field and difference schemes are compared. The solution obtained for the case of injection of a pulsed jet is compared with the solution for the case where a valve prevents gas flow through the injection nozzle. The dependence of the control force produced by gas injection on time is investigated.

The flow of combustion products containing condensed-phase particles over the recessed vectorable nozzle of a solid-propellant rocket motor was investigated with the use of the Reynolds-averaged Navier–Stokes equations, equations of the k–e model of turbulence, and the Lagrange approach. The fields of flows of combustion products and the mechanical trajectories of condensed-phase particles in the charge channel, the prenozzle space, and the nozzle unit of this motor were calculated for different angles of swing of the nozzle. The formation of vortices in the gas flow in the neighborhood of the downstream cover of the nozzle and their influence on the movement of particles different in size were considered.

Numerical simulation of gasdynamic processes accompanying the operation of the recessed nozzle of a solid-propellant rocket motor in its linear displacement is carried out. Reynolds-averaged Navier–Stokes equations closed using the equations of a k–e turbulence model are used for calculations. The calculations are done for different rates of flow of the gas in the main channel and in the over-nozzle gap, and also for different displacements of the nozzle from an axisymmetric position. The asymmetry of geometry gives rise to a complicated spatial flow pattern characterized by the presence of singular points of spreading and by substantially inhomogeneous velocity and pressure distributions. The vortex flow pattern resulting from the linear displacement of the nozzle from an axisymmetric position is compared with the data of experimental visualization. The change in the vortex pattern of the flow and in the position of the singular points as a function of the flow coefficient and the displacement of the nozzle from the symmetry axis is discussed.

Background. Severe thermal injuries accompanied by the development of endogenous intoxication, causing severe structural and metabolic disorders not only of the skin, but of all organs and body systems of burned organism. But lesser known submicroscopic changes of testis – the central organ of male reproductive system in dynamics after burn injury. Objective. The aim of this work was to established ultrastructural reorganization of the testes at early stages after experimental thermal injury. Methods. Experiment has been carried out on 20 mature white rats-males. Burn applied under ketamin anesthesia for 18-20% of hairless body surface of animals. Histological studies indicate the development of third-degree burn of skin. Experimental animals were decapitated on the 1st, 3th and 7th days of the experiment (early stage of shock and toxemia). Collecting the material for electronmicroscopic research conducted under the conventional method. Results. Electronmicroscopic research of the testes on the 1st day after thermal injury (stage of shock) detected adaptive-compensatory reorganization of the structural components of organ. Arterioles, venules and hemocapillaries have expanded lumens filled with blood cells, mainly erythrocytes. Vessel walls are irregularly thickened due to swelling of the endothelial cytoplasm and basement membrane. There are degranulation and mitochondrial hypertrophy in the cytoplasm of a part of Leydig cells that have perivascular location. There are also signs of reorganization of spermatogenic epithelium. Small amount of spermatogonia with signs of mitosis are available. Sertoli cells are moderately changed. Primary and secondary spermatocytes include round nucleus that have euchromatin and small clumps of heterochromatin in carioplasm, and small amount of organelles in the cytoplasm. Some spermatids and spermatozoa have damage structure of acrosome, observed high electron density of nucleus. At the early stage of toxemia (3th, 7th day of experiment) detected signs of destructive changes in the blood capillaries of the stroma and structural components of convoluted seminiferous tubules of the testes of experimental animals. Conclusion. Under burn shock ultrastructural reorganization of microcirculatory bed, walls of convoluted tubules and spermatogenic epithelium has adaptive-compensatory character. At the early stage of toxemia thermal lesions of animals skin lead to destructive changes in the blood capillaries, endocrinocytes, submicroscopic organization of structural components of the convoluted seminiferous tubules., В эксперименте на белых крысах – самцах проведены электронномикроскопические исследования структурных компонентов симяников в ранние сроки после тяжелой термической травмы. Установлено что в стадии шока происходят приспособительно-компенсаторные изменения микроциркуляторного русла, стенки извитых семенных канальцев и сперматогенного эпителия. В стадии ранней токсемии (3, 7 сутки опыта) выявлены признаки деструктивных изменений кровеносных капилляров, стромы и структурных компонентов извитых семенных канальцев органа экспериментальных животных., В експерименті на білих щурах–самцях проведені електронномікроскопічні дослідження структурних компонентів сім’яників в ранні терміни після тяжкої термічної травми. Встановлено, що в стадії шоку відбуваються пристосувально-компенсаторні зміни мікроциркуляторного русла, стінки звивистих сім’яних канальців та сперматогенного епітелію. В стадії ранньої токсемії (3, 7 доба досліду) виявлені ознаки деструктивних змін кровоносних капілярів, строми та структурних компонентів звивистих сім’яних канальців органу експериментальних тварин.

A numerical simulation of the hydrodynamic effects arising in the process of work of the vectorable thrust nozzle of a solid-propellant rocket engine has been performed. The fields of the flows of combustion products in the channel of a charge, the prenozzle space, and the nozzle unit were calculated for different angles of vectoring of the nozzle. The distributions of the gasdynamic parameters of the flow of combustion products in the prenozzle space, corresponding to their efflux from the cylindrical and star-shaped channels of charges, were compared. The formation of a vortex flow in the neighborhood of the back cover of the nozzle was considered.

Subject of Research. Numerical simulation results and investigation of shock wave diffraction of differentintensity on the flat right angleare presented. Method. The numerical model is based on the solution of unsteadyEuler equations for inviscid compressible gas. The finite volume method and explicit WENO-type difference scheme of the third-order of accuracyare used. Convective fluxesare calculated independently for each direction with the approximate Riemann solver(HLLC method). Time integration is performed with the Runge-Kutta method of the third order. Main Results. Flow structure and flowquantitative characteristicshave beendetermined. To visualize and interpret the results of numerical calculations theprocedure of identification and classification of gas-dynamic discontinuities has beenappliedbased on the use of dynamic compatibility conditions and methods of digital image processing. The results of calculations have beenpresented in the form of numerical shadow pictures, schlieren images and interferograms, and compared with the optical observations. Significantly better agreement with the experimental data has beendemonstrated as compared toconventionalnumerical methods. Application of numerical methods of high order accuracy has yielded a numerical solution which is free from non-physicaloscillations on the shock waves with minimal smearingoverdifference cells. Practical Relevance. The study of shock-wave phenomena is of interest for the solution of problems related to the impact of shock waves on the design elements, the operation of pulsed gas-dynamic devices, the use of shock waves in technological processes. Supersonic flows around angle configurations lead to interference and diffraction phenomena complicated by flow separation. These effects make complexthe calculation of such phenomena using conventional numericalmethods. The problem ofthe results interpretation is not less complicated one,as well, in particular, identification of gas-dynamic discontinuities.

We consider current problems of improving propulsion systems of highly supersonic air-space vehicles. In the first part, we review historic developments and list the landmark scientific papers. Classification of detonation engines is presented with detailed consideration of rotation detonation engines and continuous detonation engines. Experimental results on detonation, which are of particular importance for the design of detonation engines, are discussed. The second part of the paper provides an overview of the development in detonation theory, mathematical modelling, and numerical simulation. We focus on the interference of shock waves with formation of triple points, regular and irregular reflection of shock waves, existence of multiple solutions and the resulting appearance of hysteresis. The relevance and importance of triple shock wave configurations for the development of new types of air intakes and detonation jet engines is demonstrated.

Using a quadripole network, a model has been built for a metalworking-machine pump unit consisting of a triple plunger pump. It is shown that the use of a high-speed electric motor may lead to the appearance of resonance with a pump-unit manifold, and as a result, the equipment for pulsations control fails to operate effectively. To solve the problem it is necessary either to update the pump manifold in order to change its oscillation eigenfrequency or to use a different motor speed.

The atmospheric composition behind a normal shock ahead of a hypersonic vehicle differs from the atmosphere ahead of the shock. Various models of air equilibrium composition are compared, analysis of areas of these models applicability is performed. Numerical simulations of flow in a channel with a step are performed using models of perfect gas and high-temperature air. The results computed with both models are compared.

УДК 532.529 ПРОИЗВОЛЬНОЕ ВЗАИМОДЕЙСТВИЕ ПЛОСКИХ СВЕРХЗВУКОВЫХ ПОТОКОВ П.В. Булат, К.Н. Волков a Университет ИТМО, Санкт-Петербург, 197101, Российская Федерация b Университет Кингстона, Лондон, SW15 3DW, Великобритания Адрес для переписки: Pavelbulat@mail.ru Информация о статье Поступила в редакцию 13.07.15, принята к печати 08.10.15 doi:10.17586/2226-1494-2015-15-6-1155-1168 Язык статьи – русский Ссылка для цитирования: Булат П.В., Волков К.Н. Произвольное взаимодействие плоских сверхзвуковых потоков // Научнотехнический вестник информационных технологий, механики и оптики. 2015. Т. 15. No 6. С. 1155–1168. Аннотация Предмет исследования. Рассматривается задача Римана о распаде произвольного разрыва параметров при столкновении под некоторым углом двух плоских потоков. Задача решается в точной постановке. К задаче о произвольном взаимодействии двух сверхзвуковых потоков может быть сведено большинство случаев интерференции как стационарных, так и нестационарных газодинамических разрывов, течения за которыми – сверхзвуковые. В зависимости от соотношения параметров в потоках исходящие разрывы могут быть или скачками уплотнения, или волнами разрежения. В некоторых случаях решение может отсутствовать вовсе. Важно уметь находить области существования соответствующих решений, так как вид образующихся ударно-волновых структур в этих областях заранее известен. Задача о распаде разрыва используется в численных методах типа метода Годунова. Обычно применяется приближенное решение, известное как решение Ошера, но в ряде задач, когда требуется высокая точность, необходимо решать эту задачу в точной постановке. Основные результаты. Рассмотрены области существования решений с различными типами ударно-волновой структуры. Аналитически определены границы существования решений с двумя исходящими скачками уплотнения, а также с исходящими скачком и волной разрежения. Выявлена область чисел Маха и углов, под которым взаимодействуют потоки, при которых решение отсутствует. Специфические течения с двумя исходящими волнами разрежения не рассматриваются. Практическая значимость. Результаты работы дополняют теорию интерференции стационарных газодинамических разрывов и могут быть использованы при разработке новых методов численного расчета с выделением разрывов. Ключевые слова волна разрежения, задача Римана, распад произвольного разрыва, скачок уплотнения, ударная волна, ударноволновые структуры. Благодарности. Работа выполнена при финансовой поддержке Министерства образования и науки РФ (Соглашение No 14.575.21.0057, уникальный идентификатор прикладных научных исследований RFMEFI57514X0057).

The article is dedicated to the problem of food allergy in children. The number of patients with this pathology continues to rise, which can be explained by multiple factors, which speaks for the relevance and the social importance of the matter. For food allergy, the causesignificant allergens are both simple and complex food proteins. Wheat is one of the most prevalent source of food allergens not only for children, but for adults too. The article contains the main information concerning the ley characteristics of this product; the protein content and the different roles of individual components in forming allergic reactions and cross activity are thoroughly investigated. The authors provide recommendations for the diagnostics and treatment of wheat protein allergy, and various difficulties in different clinical cases are examined. The article also contains main treatment approaches, which are relevant to the modern data. An individual approach in each case means regular monitoring of the main figures, preventing the negative consequences of an eliminative diet at wheat protein allergy through using specialized gluten-free products.