Search

The destabilization of bone fixators has led to repeated surgical interventions that increased the risk of migrations of metal fixators, infectious and inflammatory complications as well. The modern trends in hip bone injury surgery are related to developing and using of metal fixators, which are effective in acute injury; however, sometimes the condition of the patient and the technical support of hospitals don’t allow performing surgery in the acute period, and these metal fixators are ineffective for chronic damage. Consequently, until now, the problem of finding the optimal design of structures for fixing chronic damage of anterior pelvic semi-ring which will be able to exclude its destabilization, is still of current interest.The purpose of the study: developing and experimental researching of durable features of original plate for reconstruction of the anterior pelvic semi-ring.Materials and methods: In order to ensure stable fixation of chronic pelvic injuries, the original metal plates have been worked out. They are made individually in accordance with the anatomical and functional structures of the anterior pelvic semi-ring of the patient with using additive technologies. The study of the reliability of the different variants of ostiosynthesis of the anterior pelvic semi-ring with using well-known pelvic plates and a new original design was carried out. Stability tests for different plate fixing methods and mechanical strength of metallophyxators were carried out on a universal test machine of LFM-50kN series.Results: one plate fixation in tensile test showed the lowest result – 0.341 kN, a low result of shear loads was received with the same object. The best result was shown by the polyaxial monolithic plate fixation in case of stretching – 0.51 kN at the shear loads – 0.591 kN. Necessary force applied to destabilizing of the metal structure while using a polyaxial monolithic plate was a half-higher than stretched, and a third higher than at shear loads, it demonstrates the benefits of using these metal fixators.Conclusion: It is experimentally confirmed that the polyaxial monolithic plate provides the highest stability of fixing anterior pelvic semi-ring indicator in contrast with fixing of one or two plates.

—It is known that linearly polarized translational vibrations can multiply the capture cross section of deposited solid particles by a single gas bubble suspended in a liquid. This fact is of great theoretical and practical importance for using vibrations to intensify the flotation process, which, however, involves multiple rising bubbles. The present work studied the capture of solid particles by a gas bubble ensemble in liquid exposed to high-frequency small amplitude vibrations in two-dimensional formulation numerically. The numerical solution was obtained using ANSYS Fluent software. The obtained fields of the averaged and pulsating components of the flow velocity were then processed by our own code in order to calculate the trajectories of small particles from a “cloud” located in the computational domain. The description of forces acting on the particle took the added mass of the fluid, gravity, the Archimedean force, Stokes force, Basset force, and the vibrational force due to the inhomogeneity of the pulsating field into account. The calculations were performed for millimeter air bubbles in water with particle characteristics significant for the flotation process. The influence of vibrations is shown to be significantly attenuated within the bubble ensemble due to the “screening” effect, which peaks at the highest vibration frequency and depends weakly on the distance between the bubbles. However, vibrations of a lesser frequency, at which the gas in bubbles is compressible, are still able to penetrate deep into the liquid volume at a sufficient excitation intensity, and thereby increase the particle capture region.

Objective. The high prevalence of obesity in employable population dictates the necessity for preclinical diagnosis of diseases associated with it, including the study of the autonomic regulation of heart rhythm. The objective was to study the correlations between the adipocytokine profile and heart rate variability in patients with obesity. Materials and methods. 300 persons were examined, the average age was 46.2 6.4 years; Group 1 was metabolically unhealthy obesity phenotype (MUHOP) 90 patients; group 2 was obesity without metabolic disorders [Ob(+)MD(-)] (MHOP) 50 persons; the control group consisted of 100 healthy respondents. We studied the following indices: blood serum adipocytokines: leptin, insulin, resistin, adiponectin. Heart rate variability was studied using Poly-Spectrum Rhythm 2012 computer electrocardiograph. Results. In the course of the study, decrease in the total heart rate variability and reactivity of the parasympathetic part of the autonomic nervous system in patients from MUHOP group was found, while there were no differences with the control in the MHOP group. It was established that a decrease in the parasympathetic effect on the regulation of heart rhythm is associated with the presence of abdominal obesity, insulin resistance, and an increase in the level of TG, glucose, resistin, and uric acid. Conclusions. The received relationships between indicators of carbohydrate and lipid metabolism, the level of uric acid and adipocytokines with temporal and spectral characteristics of the autonomic nervous system confirm their contribution to the development of autonomic dysfunction in obese persons.

Gravitational–capillary waves, arising in a system of thick layers of two aggregate states of a substance, are studied using the example of water and its vapour. Their initially flat interface is in hydrostatic and thermodynamic equilibrium at atmospheric pressure and the corresponding saturation temperature $100\,^{\circ }\text{C}$, provided that a balance is maintained for heat fluxes transported through immovable phases in the process of heat conduction. From the problem of linear stability for small perturbations, estimation relations for their damping coefficient and eigenfrequency shift are obtained, including the factors of viscosities of the media and phase transition. The first two contributions, proportional to the kinematic viscosity of the liquid and the square root of the kinematic viscosity of its vapour, respectively, are consistent, accurate to additionally accounted for capillary forces, with the result of Dore’s analysis, which is a development of the weakly viscous Lamb theory for ‘deep water’. Numerical calculations have shown that, with increasing wavelength, the accuracy of the proposed approximation increases, especially for the wave damping coefficient, and the contribution of the viscosity of the light phase increases in percentage terms. As for the phase transition effect, which was previously overestimated using the quasi-equilibrium approximation, it remains insignificant at the level of heat fluxes acceptable in the model of thick layers of homogeneous media. The factor of thermocapillarity is found to be very weak; it becomes qualitatively noticeable only on the background of disappearing heating. Here, together with the factor of dependence of the saturation temperature on the phase pressure, it determines a non-zero correction to the wave damping coefficient.

Sympathetic innervation of the stomach is carried out by the prevertebral ganglia of the solar plexus. The localization and neurochemical composition of neurons innervating the stomach in the postnatal ontogenesis of rats have been studied by the method of retrograde axon transport of Fast Blue. In all animals, the celiac ganglia had more labeled neurons than the superior mesenteric ganglion. The number of labeled neurons increased in the first ten days of life and then did not change until senescence. All labeled neurons innervating the stomach contain tyrosine hydroxylase, the catecholamine synthesis enzyme. The proportion of labeled neuropeptide Y-immunopositive neurons did not change during ontogeny; the percentage of labeled calbindin-immunoreactive neurons decreased in the first month of life.

A computational package CrystarPack developed by the author is presented, which is designed to solve problems of continuum mechanics according to an implicit scheme using finite difference and finite volume methods on a Cartesian grid with a refined step, as well as a modified iterative Newton method with global convergence. The package has the form of a dll-library and is flexible and easy to customize for various physical problems, allowing its functionality to be included in the user-written code in any of the imperative programming languages.

The purpose of the work is to reveal the influence of conical directing agents on the speed and trajectory of particles movement in the vertical pneumatic conduit of the sowing machine and to establish their rational parameters. With the help of numerical modeling the particle flight trajectories in the air flow were obtained. The carried out researches have shown expediency of application of the conical directing agent, allowing to take away a longitudinal stream of particles from walls of a pneumatic conduit and to centre their trajectories of movement along an axis of a pneumatic conduit. Particles are focused to the center of the distributor when the distributor covers the area of pneumatic conduit cross-section close to 25%.

The purpose of the research was to develop a methodology for calculating the power factor of the rotary agitator unit drive with its components and an algorithm for their determination, implemented in the form of a computer program. The structural scheme of the bulk material mixer with the developed agitator unit is given. The definition of the required parameters is realized on the base of the known expressions and operating parameters of the mixer. The developed technique and calculation algorithm, which is realized in the MathCAD mathematical package, allow determining the peripheral velocity profile parameter of the material and the hydraulic resistance coefficient of the working body, the power factor and the mixing capacity factor, which allows calculating the torque and power required for material mixing by a rotary mixer with a vertical shaft of the developed design.

Comparative analysis of methods of obtaining electricity from a renewable energy source is carried out. Various designs and op-tions for small hydroelectric power plants have been proposed. Positive and negative factors of structures under consideration and their impact on the environment are analyzed. The main characteristics of the flow (speed, head) for the choice of the optimal variant of hydroelectric power plant have been determined. Three variants of impellers for free-flow hydroelectric power plants are proposed with a comparison of the efficien-cy of each variant. An analysis was carried out and an impeller based on a Darrieus rotor was selected for further research. Simulation was performed in the Flow Simulation program. The initial data for the design of Darrieus rotor operating in a liquid were the diameter and width of the impeller. The calculations involved a rotor with straight and swirling blades. The swirling blades rotor is self-starting. In the course of the calcula-tion, the speed of the liquid flow approaching the rotor and the rotor speed were changed. As a result of cal-culation, the value of the positive moment for self-starting was determined, which occurs at an incident flow velocity of at least 1.3 m/s.

In the present work, we study the resonance oscillations of a single liquid drop or gas bubble relative to their equilibrium spherical shape, which arise as a result of harmonic, translational vibrations of a volume of liquid of different densities, containing such an inclusion. The parametric resonance of the forced translational mode with the main resonant frequency equal to the sum of two adjacent eigenfrequencies of capillary oscillations of the interface was previously discovered in an inviscid approximation [Lyubimov et al., “Resonance oscillations of a drop (bubble) in a vibrating fluid,” J. Fluid Mech. 909, A18 (2021)], also taking into account low viscosity using a phenomenological approach. Now, the effect of viscosity on the resonance is investigated by rigorous accounting for the viscosity in the dynamic boundary layer near the interface. The relations governing the evolution of the resonance modes near the threshold of instability excitation are determined. The equivalence of the two approaches taking viscosity into account is revealed: the rigorous one, built on a method of multiple scales, and the previously developed phenomenological approach, which is based on the artificial addition of the dissipative terms to the amplitude equations.

The purpose of research is justification of area efficiency of the proposed mixer with vertical shaft and paddle stirrer, the edges of the blades which are fixed sinusoidal blades. Research has shown that, by virtue of the kinetics of mixing all the mixers in the early period mixing significantly improve the quality of the mixture, after which stabilization of the quality indicators, and in some cases starts and segregation of the mixture. The nature of the change of the uniformity of the mixture is kind of exponential time mixing. In this connection there is the task of identifying areas of efficiency and opportunities the application of paddle mixer proposed design for the preparation of dry feed mixtures. Important manufacturing concentrate mixtures (compaund feeds, feed concentrates or forage medicinal mixtures) based on the purchase of BVD and your own forage. Purpose: the establishment of functional dependence between the technological parameters of the mixer (the proportion of the control component and the duration of mixing) and process performance (uneven mix and adjusted intensity of mixing taking into account the uniformity of the mixture); identifying rational values of technological parameters of the mixer, providing the desired quality mix and minimum energy intensity of mixing. It is provided the description and structural diagram mixer dry material batch. The technique is described and results of experimental studies of the mixer. It is presented the expressions describing the unevenness of the mix and the energy intensity of stirring, depending on the proportion of the control component and the duration of mixing; the required duration of mixing depending on the proportion of the control component. It is built two-dimensional section of the surface response in the studied parameters. Based on the analysis of the given graphs justifies the area efficiency of the mixer: the proportion of the control component is not less than 3%; when the portion of the control component 5% duration of mixing – 300 s, when the portion of the control component 10% the duration of the mixing – 200 s.

The influence of the assembly conditions on the rotary drag torque and static load capacity of thrust ball bearings is studied experimentally. It is found that the ball parameters and the ratio of the ball radius and the raceway radius affect the drag torque and static load capacity of the bearings. Optimal bearing geometry is established.

Fatigue and residual strength tests were performed of the wing box, which was manufactured using a polymer composite material according to a new infusion technology. There are investigated influence of the technological effects (porosity, delamination, etc.) and operational (impact) defects on the durability and strength of the composite structure.

Sympathetic innervation of the stomach is carried out by the prevertebral ganglia of the solar plexus. The localization and neurochemical composition of neurons innervating the stomach in postnatal ontogenesis in rats was studied using the method of retrograde axon transport of Fast Blue. In all animals, the celiac ganglia had more labeled neurons compared to the superior mesenteric ganglion. The number of labeled neurons increased in the first 10 days of life and then did not change until the senescence. All labeled neurons innervating the stomach contain the catecholamine synthesis enzyme, tyrosine hydroxylase. The proportion of labeled neuropeptide Y-immunopositive neurons did not change in the development, the percentage of labeled calbindin-immunoreactive neurons decreased in the first month of life.Симпатическая иннервация желудка осуществляется превертебральными узлами солнечного сплетения. Методом ретроградного аксонного транспорта быстрого голубого (Fast Blue) исследовали локализацию и нейрохимический состав нейронов, иннервирующих желудок в постнатальном онтогенезе у крыс. У всех животных в чревных узлах выявляли больше нейронов, содержащих метку, по сравнению с краниальным брыжеечным узлом. Количество меченых нейронов возрастало в первые 10 сут жизни и далее не изменялось вплоть до старости. Все меченые нейроны, иннервирующие желудок, содержат фермент синтеза катехоламинов — тирозингидроксилазу. Доля меченых нейропептид-Y-иммунопозитивных нейронов не менялась в онтогенезе, доля меченых кальбиндин-иммунореактивных нейронов снижалась в первый месяц жизни.

Production of high-viscosity oil and design of field development systems for such oil is one of the most promising directions in the development of world oil industry. As a rule, oil of this class has pronounced structural–mechanical properties. Nonlinear relationship between the pressure gradient and the rate of oil flow is due to the interaction of high-molecular substances, in particular, asphaltenes and tars that form a plastic structure in it. We have used the analytical model of stationary influx of nonlinear viscoplastic oil to the well bottom in order to provide rationale for the intensifying impact on a reservoir. We have also analyzed the method of periodic heating of a productive reservoir by means of dual-wells. The suggested method of systemic treatment of reservoirs with dual wells can be useful for fields of high-viscosity oil.

In the article we discuss the results of a comparison of interfacial activity and component composition data for petroleum sulfonates (PS) synthesized from an extract of selective N-MP refining of side stream II and for dimeric PS prepared from the same source in the presence of paraform (paraformaldehyde)—a component responsible for the formation of disulfonic acids. The prepared technical anionic PS are characterized by a higher molecular mass (688 g/mol) and lower CMC values (40-fold for the mass 120 concentration and 500-fold for the molar concentration) relative to paraform-free sulfonation of hydrocarbons. Surfactants with low CMC values sourced from the low-quality multitonnage hydrocarbon feedstock are promising in a search of formulations for chemical flooding of reservoirs.

The purpose of the study is to increase the strength of the collected compounds and to expand the technological accuracy of the method of Assembly with an interference fit. Fixed press-fit connection with interference are widely used in machine building, when the transfer of substantial axial forces are required, torques or combined loads from their joint action. Resistance to mutual misalignment of the parts in these compounds is created and supported by the forces of elastic deformation on the mating surface of the covered part (shaft) and stretching on the mating surfaces of the covering parts (holes) is proportional to the magnitude of the preload in the connection. In such compounds, the diameter of the shaft before Assembly is always larger than the diameter of the hole. In the article the analysis of the known different ways of joining parts with interference fit, including hydraulic presses. The second problem is solved due to the fact that the connection details with tightness is carried out by pressing the press stroke from one detail to another, and the breakdown of the compounds obtained by the relative longitudinal movement of parts, in which the breakdown is carried out periodically in the process of pushing through the transfer of force from the press stroke to pressed items to the elastic connection. The force on the press stroke is created by a hydraulic cylinder with large displacement, a resilient connection between the slider and pressed item performs in the cylinder, the fluid pressure and volume which can be adjusted by changing the stiffness and capacity of the drive RAM, as well as the magnitude of its longitudinal movement during the disruption. The scheme of Assembly of the connection de-hoist with tension. Original technical solution for press fit connection parts extends the technological possibilities of the equipment, increases the strength of the collected compounds and can be used in machine building, particularly in mechanical Assembly processes and, in particular, in the repair and production of agricultural machinery.

Petroleum sulfonates with the active substance content from 21 to 32.5 % wt were prepared from four extracts of solvent refining by phenol and N-methylpyrrolidone (oil side streams II and III) in laboratory conditions. Their average molecular weight, composition, and surface activity were evaluated using a rotating drop test. The sulfonated products were characterized by NMR, IR spectroscopy, and HPLC methods.

Hydroabrasive cutting may be intensified by swirling of the working jet of suspension. In addition to fatigue failure of the machined material, the swirling activates abrasive cutting.

The shaping of a part machined by an abrasive tool with overrun is analyzed. Calculation of the overrun associated with minimum shape error—the optimal overrun—is considered.

The geometric stabilization of bearing races by centerless rolling is studied experimentally, for the outer races of ball bearings.

The purpose of the research is to establish the relationship of the geometric parameters of the sinusoidal paddles of a mixer with part of the motion indicators of low-altitude radial sectors of bulk material and the possibility of numerical simulation using existing characteristics. The effect of the flat and sinusoidal mixer blades of the blender, in terms of their construction, on the process of moving layers of the mixed material has been theoretically studied. The equations obtained allow us to state that, due to the difference in the geometry of the blades' surface, when the blades are flat, an inertial shock occurs when the blade contacts the material sector due to its sharp acceleration to the peripheral velocity. With sinusoidal blades, acceleration to a specified velocity is stretched in time, taking into account the amplitude of the sinusoid, reducing the energy cost of the friction of material layers. The obtained equations allow us to identify the relationship and numerically simulate the change in the main indicators of the material position in the blender.

The paper introduces a computer-based methodology, the aim of which is to determine a watering-place radius for flocks of sheep grazing in distant pasture lands within the arid ecosystem. All calculations leading to the quantitative values are performed through mathematical modeling which is the base of the methodology we propose. The mathematical modeling is performed through some analytical method including the sequential parameters calculation with mathematical formulas. The object was theoretically described, an algorithm was compiled in the form of a block diagram, and a computer program SUARU in the QBASIC language was developed. A series of computational experiments was carried out, aimed at analyzing, interpreting and comparing the analytical modeling outcomes. At the same time, graphical dependencies are presented to show clearly the dependence between the calculation results and the source data. The calculation methodology allows modeling the object of study depending on various values of significant parameters and applying it in practice by drawing up appropriate recommendations for farms which deal with sheep breeding when grazing lands of the arid ecosystems are used.

Ethanol is a valuable product that is widely used in various sectors of the economy. In the alcohol industry, various wastes are generated - post-alcohol distillery stillage, by-products of the distillation of ethyl alcohol, microorganism cells, among which a significant amount is the post-alcohol distillery stillage. Disposal of stillage is an urgent environmental problem, since this waste of alcohol production has a short shelf life. There are methods for processing bards that can be divided into two groups: methods using biotechnology and methods based on physicochemical methods. There are many research projects that focus on the production of biofuels and fodder product from stillage. The most common method for processing post-alcohol stillage in the Central Black Earth Economic Region is drying. We have proposed a method for the integrated processing of post-alcohol stillage of distiller’s grains, which includes drying the distiller’s grains, aerobic microbiological processing to obtain a protein feed product and the production of hop-vinous fermentation. Getting sourdough is the first proposed method for recycling bards. For drying, it is proposed to use 30% of the stillage of the enterprises of the Central Black Earth Economic Region, to produce protein feed product 50%, and for hop-burgundy starter culture 20%. The method of complex processing expands the use of post-alcohol distillery stillage, and the production of hop-burgundy sourdough allows to increase the assortment of functional food products.

The purpose of the work is to model the performance of the disk grain shredder by numerical methods of determining the performance of the device and its components, and to establish the existing trends in the influence of the size of the initial particles on the components of the shredder performance. The increase in the initial particle size leads to an increase in the initial angular velocity of the particle movement, which increases as the particle is compressed, while the increase in particle size does not significantly reduce the productivity of the shredder due to the worsening conditions of particle capture by the disks as they increase in size. The increase in the initial spring compression force ensures a reduction in the thickness of the resulting flattened particles and at the same time reduces the productivity.

The aim of the study is to develop a mathematical model of linear calculation of the pneumatic system of a seeder with a pneumatic sowing system, implemented in the MathCAD computer algebra system. The description of the pneumatic transport system of a typical seeder with pneumatic sowing is presented, its design scheme is given. Based on the provisions of the mechanics of continuous media, a methodology for calculating the parameters of a pneumatic system to verify the adopted design decisions has been developed. A computer model of a pneumatic transport system with series-parallel arrangement of sections has been developed. Linear calculations with structurally implemented recounting of indicators were performed. The obtained value of the standard deviation between the calculated average values and the velocities of the flow core in the sections does not exceed 14% for the values of the velocities and 0.5% for the pressure over the sections. When implementing the proposed analytical modeling in the MathCAD 8.0 system, the error in mass flow rate is 1.152×10-14%, which allows limiting the number of conversion cycles of indicators to two – three cycles.

It is proposed to use the fracture model and the criterion equation of a generalized crackresistance diagram in two-parameter fracture macromechanics to estimate cracking resistance and construct crack-resistance diagrams of polymer composite materials in tension and compression; these fracture model and criterion equation take into account the degree of restraint of deformations near the crack tip in the form of nonsingular T-stresses. A good agreement between the experimental values of normalized stress-intensity factors and a diagram of the calculated crack-resistance of polymer composite materials has been obtained in a wide range of crack lengths using various geometry and arrangements of specimen loading for seven carbon plastics with various orderings produced by different manufacturers using pressure-chamber and infusion methods.

The catalytic properties of CoMoS/Al2O3 and K–CoMoS/Al2O3 laboratory catalysts versus those of the commercial catalyst NK-100 (CoMo/Al2O3) have been investigated in the hydrotreating of the heavy fraction of cat-cracked gasoline (CCG). The basic kinetic parameters of the hydrodesulfurization and olefin hydrogenation processes have been experimentally determined. The addition of 7.5 wt % potassium to the CoMoS/Al2O3 catalyst decreases both the apparent activation energy and preexponential factor of both processes and increases the selectivity coefficient by a factor of over 3. Selective hydrotreating of the heavy fraction of CCG has been carried out over a K–CoMoS/Al2O3 sample at a temperature of 280°C, a pressure of 1.5MPa, a feed hourly space velocity of 7.5 h–1, and H2: feed = 100 NL/L. As a result, the sulfur content of gasoline has been reduced from 92 to 13 mg/kg without affecting the octane number. If the proportion of CCG in commercial gasoline obtained by compounding CCG with other components is 20–35%, the sulfur content of the product will meet the environmental requirements imposed on Class 5 fuels according to regulations.

The effect of evaporation and condensation on the Rayleigh-Taylor instability is studied with a rigorous approach, finding that phase change induces an additional flow that affects heating of the interphase boundary. This reduces the ratio of the phase change rate to the interface position deviation.

Generation characteristics of a pulse-periodic oxygen–iodine laser with the electro-discharge production of atomic iodine were compared with inductively stabilised edged or anisotropic- resistive cathodes used for ignition of the volume discharge. The discharge was initiated by the radiation of a barrier discharge from the side of a grid anode. It was found that at equal specific electrical energy depositions to the gas-discharge plasma, the system with the anisotropic-resistive cathode provides a more stable and uniform volume discharge with the possibility of varying the composition and pressure of working mixtures over a wide range and a greater specific extraction of laser energy is observed (up to 2.4 J L{sup -1}). At a high pulse repetition rate of laser pulses (50 – 100 Hz) and long duration of the pulse trains (longer than a minute) the surface of anisotropic-resistive cathode became eroded. (laser applications and other topics in quantum electronics)

Calbindin (CB)-containing neurons in the cranial cervical, stellate, and celiac sympathetic ganglia of rats (n = 60) aged 3–90 days were studied using an immunohistochemical method. The results obtained demonstrated that the stellate ganglion contained the greatest proportion of CB-immunopositive neurons. The proportions of CB-immunopositive neurons in the para- and prevertebral sympathetic ganglia decreased with age. The formation of the group of CB-immunopositive neurons in sympathetic ganglia was complete by the end of the first month of life.

The effect of Co/Mo ratio in the CoMo/Al2O3 hydrotreating catalysts prepared by simultaneous using of the decamolybdodicobaltate heteropolyacid (Со2Мо10HPA) and cobalt citrate was investigated. Synthesized catalysts were characterized by Raman spectroscopy, N2 adsorption, XRD, XPS, HRTEM techniques and were examined in the model reaction of 4,6-dimethyldibenzothiophene (4,6-DMDBT) HDS, in hydrotreating of straight-run gas oil (SRGO) and mixture of 80 vol.% SRGO with 20 vol.% light coker gas oil (LCGO). It was established that Co/Mo ratio in the catalysts significantly influences on the structure of CoMoS phase of type II and catalytic activity. Catalysts with λ = Co/(Co + Mo) = 0.35 had maximal activities in 4,6-DMDBT HDS and diesel HDT and showed the best stability. Increase of the Co/Mo ratio led to simultaneous growing of both average length and stacking number of CoMoS multilayer active phase of the catalysts. Average length increased from 3.0 to 4.0 nm, average staking number increased from 1.4 to 1.6. It was found out that catalysts activity decreased within Co/Mo ratio λ from 0.35 to 0.45. Analysis of textural properties of the catalysts, active phase morphology, phase composition and catalytic activities allowed us to suppose that with increase of Co/Mo ratio blocking the mesopores by sulfides of the active components and by coke species with formation of new micropores would take place. The activity of the best prepared CoMo/Al2O3 catalyst was competitive with the activity of the well-known commercial catalysts for ultra-low sulfur diesel in hydrotreating of SRGO or mixture of SRGO with LCGO.

The oscillation spectrum of a compound drop, consisting of two immiscible liquids, one constituting a liquid central core, surrounded by a liquid layer of the second liquid, resembles that of two coupled harmonic oscillators. From frequency analysis it is possible to determine the surface tension of the outer liquid, and the interfacial tension between the two liquids. In previous treatments of the problem it has been always assumed that the inner core and the outer shell are concentric. This is not necessarily true; this paper removes this restriction and discusses the influence of non-concentricity on the frequency spectrum. It is shown that, except for particular cases, the correction is of second order in eccentricity. Also, the degeneracy of the concentric system with respect to the azimuthal number is lifted.

Co(Ni)MoS/Al2O3 catalysts have been prepared from ammonium 10-dodecamolybdodicobaltate (NH4)6[Co2Mo10O38H4] (further, Co2Mo10HPC) and cobalt(nickel) salts of 10-dodecamolybdodicobaltic acid H6[Co2Mo10O38H4] (hereinafter, Co2Mo10HPA). It has been found that a high activity of the Co(Ni)3-Co2Mo10HPA/Al2O3 catalysts in the hydrodesulfurization and hydrogenation reactions is due to the formation of a nanostructured type II CoMoS phase via the contact of the metals (Mo and Co(Ni)) at the molecular level. The use of Ni as a copromoter in the Ni3-Co2Mo10HPA/Al2O3 catalyst leads to a simultaneous increase, compared with Co3-Co2Mo10HPA/Al2O3, in the linear size of nanoparticles and the number of MoS2 layers in the packing of active phase. The nature of the promoter X has a substantial effect on the properties of X3Co2Mo10HPC/Al2O3 catalysts. It has been found that the catalysts with X = Co exhibit the highest activity in the hydrodesulfurization reactions and those with X = Ni, in hydrogenation reactions.

Catalysts have been synthesized using the Anderson polyoxometalates (POMs) (NH4)4[Ni(OH)6Mo6O18] (NiMo6POM), (NH4)6[Co2Mo10O38H4] · 7H2O (Co2Mo10POM), and H6[Co2Mo10O38H4] (Co2Mo10HPA) as the precursors and hydrogen peroxide as the solvent. The catalysts have been characterized by low-temperature nitrogen adsorption, XPS, and HRTEM. Their catalytic properties have been tested in thiophene hydrodesulfurization and in the hydrodesulfurization and hydrogenation of components of diesel oil. The active phase of the catalysts synthesized using the POMs is the type II CoMoS phase in which the mean plate length is 3.6–3.9 nm and the mean number of MoS2 plate per plate packet is 1.8–2.0. Use of hydrogen peroxide provides an efficient means to reduce the proportion of Co2+ promoter atoms surrounded by oxygen in the case of an impregnating solution containing both an ammonium salt of a heteropoly acid and a Co2+ salt. In the catalysts synthesized using cobalt salts of Co2Mo10HPA, the support surface contains the multilayer type II CoMoS phase and cobalt sulfides. These catalyst show high catalytic properties in thiophene hydrogenolysis and diesel oil hydrorefining. Models are suggested for the catalysts synthesized using Anderson POMs.

This paper presents an investigation of the detachment of a bubble from a solid flat substrate according to a dynamic scenario, i. e., due to strong vibrations of the surface shape of the bubble caused by normal nonacoustic harmonic vibrations of the substrate. The Layzer’s model based on an analysis of single-mode solutions near the bubble top was used to study its detachment in microgravity, where the dynamics of the bubble surface is due to competition between liquid inertia forces and surface tension forces. Detachment of the bubble from the substrate was determined from the condition of its elongation during vibrations by a magnitude comparable to the radius of the bubble in equilibrium. The dependence of the vibration intensity required for the detachment of the bubble on the problem parameters was determined using a number of empirical assumptions. The volume of the detached bubbles was estimated.

With the Chusovckoy water intake of the city of Perm as a study case specific features of organization of selective water abstraction from water bodies in the conditions of essential vertical heterogeneity of limiting contamination ingredients content have been considered. The watercourse vertical stratification is caused by the Chusovaya and Sylva rivers (with substantially different hydro/chemical regime) confluence in direct vicinity of the water intake. Simulation computing experiments in three-dimensional statement with the use of ANSYS Fluent software have been carried out to assess the bottom barriers’ effectiveness in arrangement of selective water abstraction.

The influence of gas temperature on the characteristics of a self-sustained volume discharge was studied in the working mixtures of a chemical oxygen – iodine laser with pulsed electricdischarge production of iodine atoms. In experiments, laser working mixtures were modelled by the mixture of air and iodide C{sub 2}H{sub 5}I. It was established that mixture heating is accompanied by an increase in the voltage across the discharge plasma and by a decrease in the discharge current. By varying the temperature of the mixture with the iodine content of ∼2.7% and initial pressure p=12 Torr from 22 °C to 96 °C, the current amplitude falls by ∼12%, and at the instant corresponding to a maximal current the voltage raises by ∼22%. Such a change in the discharge characteristics is explained by a higher rate of electron attachment to vibrationally excited iodide molecules at elevated temperatures. (active media)

Experimental data are presented regarding the influence of residual deformation after abrasive machining and centrifugal finishing on ball-bearing assembly.

In the present work, the possibility of joint separation of mechanical impurities and asphaltenes from intermediate layers of oil sump with the use of limiting hydrocarbon solvents and the centrifugation method was investigated, and an assessment of the effect of the separation stage on the efficiency of the oil dehydration processes was carried out. It is shown that the dilution of the hydrocarbon phase of the intermediate layers with a solvent from the saturated hydrocarbons (a broad fraction of light hydrocarbons from the oil stabilization block is used as the solvent), followed by centrifugation, allows the separation of heavy hydrocarbons, mainly asphaltenes and mechanical impurities into a separate phase. The analysis of structural and group structure of an initial hydrocarbonic phase and the allocated deposit showed that in settling 81.6 % of a mass fraction of asphaltenes and 93.6 % of a mass fraction of mechanical impurities of their initial con-tents in a hydrocarbonic phase of the interlayer concentrate. The ultimate analysis of structure of the deposit determined by a method of a X-ray fluorescent spectroscopy showed the high content of vanadium (0.4 % of a mass fraction) comparable to the main-tenance of this element in metallic ores that allows to use the allocated deposit for pro-cesses of a demetallization. Comparative tests of sediment influence on oil dewatering processes performed with the use of a bottle dough in the presence of an industrial demulsifier at the technological parameters of the dewatering unit of the oil treatment unit showed that the separation of the sediment from the hydrocarbon phase of the intermedi-ate layer substantially increases the efficiency of the oil dehydration processes. Results of the executed research can be used for creation of technology of utilization of interlayers of settlers of the oil directed to increase in effectiveness of processes of a deaquation and decrease in number of technological failures of installations of preparation of oil.

Представлена библиотека встраиваемого программного кода CrystarPack, реализованная в виде набора dll-библиотек. Ключевой идеей библиотеки является «паспортизация» точек вычислительного домена. Каждая точка получает свой «паспорт», однозначно выделяющий ее из прочих точек и передающий физическое содержание, сохраненное на этапе дискретизации уравнений решаемой задачи. Это делает возможным отделение постановочной части расчетной программы от программной реализации численного метода и организацию вычисления невязок от дискретизированных уравнений в терминах, близких к постановке самой задачи. Библиотека протестирована на простых задачах, на примере одной из которых – задаче конвекции в квадратной полости при нагреве сбоку, выполнена оценка ее производительности.

The effect of normal vibrations of a flat horizontal heater on the second boiling crisis is considered within the framework of the hydrodynamic theory of boiling crises. The critical heat flux is estimated by characteristics of growth of the most dangerous disturbances destroying the liquid-vapor interface. As the vibration intensity increases, the interface can be destroyed either owing to the Rayleigh-Taylor instability or by virtue of parametrically excited disturbances with wavelengths corresponding to resonance zones. In the domain of parameters where the parametric instability in the first resonance zone is the most dangerous factor, it is possible to significantly reduce the critical heat flux, as compared with the value corresponding to the case with no vibrations. With a further increase in vibration intensity, the critical heat flux increases as a whole. The nonmonotonic character of the critical heat flux as a function of vibration intensity allows an effective control of the critical heat flux whose value can be made higher or lower than the value in the case without vibrations.

Electron paramagnetic resonance (EPR) spectroscopy and photo-induced EPR are used to examine the point defects in vanadium-doped 4H–SiC and high-purity semi-insulating (HPSI) 4H–SiC grown by physical vapor transport. Both types of samples often exhibit a 1.1-eV activation energy, Ea, as extracted from the temperature-dependent Hall/resistivity measurements; however, different defects are related to the same Ea in each case. In the vanadium-doped wafers, the EPR data reveal both V4+ and V3+ in the same sample; thus, the 1.1-eV Hall activation energy is tentatively interpreted as the V3+∕4+ acceptor level. However, this conclusion cannot be confirmed because additional defects complicate the photoresponse of vanadium. The carbon vacancy, which is detected in all the HPSI wafers, exhibits a range of photothresholds similar to the various values measured for Ea. The photo-EPR and temperature-dependent Hall/resistivity measurements made before and after a 1600°C anneal suggest that several different types of nonuniformly distributed defects participate in compensation of the HPSI material and that annealing selectively removes those with different defect levels.

This work investigates the thermal stability of point defects in high-purity SiC. Electron paramagnetic resonance measurements made after Ar annealing between 600°C and 1700°C reveal changes in at least two defects, a carbon vacancy related center (VC) and the shallow boron acceptor. Between 1000°C and 1400°C, the number of carbon vacancies decreased and the number of boron acceptors increased in about the same proportion. Above 1400°C, the concentration of B continued to grow, while the number of carbon vacancies fell below the detection limit. After the highest temperature anneal, the initial preannealed concentration of VC was restored by illumination with sub-bandgap 578-nm light. The effects of heat treatment between 1000°C and 1400°C are interpreted in terms of the charge exchange between a compensated B acceptor and VC. The observation of optically induced carbon vacancies after the final anneal suggests that they are thermally stable in these samples up to 1700°C.

Electron paramagnetic resonance (EPR) has been employed to examine thermo- and photo-activated interactions between as-grown intrinsic defects and nitrogen/boron impurities in nominally high-resistivity 4H SiC produced without intentional vanadium doping. The EPR spectra, recorded in the dark at 4 K, revealed either a low concentration of paramagnetic boron, nitrogen, or a carbon-vacancy-related defect (ID-1). The photo-induced charge transfer between ID-1 and both boron and nitrogen has been detected. In some samples, illumination with 0.9-1.6-eV light at 4.2 K quenched the ID-1 signal and produced an approximately equal amount of shallow paramagnetic boron. Exposure to 1.9-2.7-eV light restored the ID-1 center and produced shallow paramagnetic nitrogen. A model based on excitation from the band edges and the threshold energies obtained from the photo-EPR data placed the ID-1 level 0.9 ± 0.1 eV above the valence-band edge. Comparison of these data with that obtained from other samples that exhibited excess boron or nitrogen impurities suggested the presence of an additional defect no more than 0.9 eV below the conduction-band edge. This defect can exchange charge with the nitrogen donor.