Advanced Materials Research Vol. 880

Abstract: Using numerical experiment one-dimensional unsteady processes of heterogeneous combustion in porous object under free convection in horizontal case have been investigated and compared with vertical case. It is shown that in the case of the horizontal porous object the oxidizer supply, which is the result of natural convection, is not sufficient for the appearance of stable wave of heterogeneous combustion. In contrast to the vertical position of the object, there are no long-lived combustion waves in the horizontal case, which completely burns down the solid combustible material. When the ignition zone is on the border of the object, the combustion wave near the vicinity of the boundary burns the oxygen and becomes extinct. When the ignition zone is in the center of the porous object, two combustion waves arise which may move very slowly, burn oxygen and become extinct.

Abstract: The time-dependent gas flows through porous objects with heterogeneous reactions are considered when the gas pressure at object boundaries is known but the flow rate and velocity of the gas filtration at the inlet to the porous objects are unknown. In such porous objects the flow rate of oxidant, which enters into the reaction zone in porous object, regulates itself. An original numerical method, based on a combination of explicit and implicit finite-difference schemes, have been developed for investigating the unsteady gas flows in such porous objects with zones of heterogeneous reactions. Used approach enables to solve problems of filtration combustion for both forced filtration and free convection, so it can be efficiently applied for modeling the combustion zones in porous media, which may arise from natural or man-caused disasters.

Abstract: The authors described a new approach to calculation of gasoline blending formulations taking into account the non-additivity of octane numbers and the composition of the raw materials with the use of the modeling system Compounding. Gasoline blending formulations developed for "Achinsk petroleum refinery" (Russia) meeting all environmental and technical standards. Applying the developed modeling system each refinery can choose necessary formulation of gasoline production taking into account composition and available flows. This will allow them to reduce the cost of gasoline and make the products more competitive.

Abstract: It is known that chemical bonding is only possible when particles with antiparallel valence electrons spins orientation collide [1, 2]. In an external magnetic field unpaired electrons spins precession around the field lines is observed. Precession frequencies of valence electrons of magnetic and nonmagnetic nuclei differ, resulting in a different probability to collide in reactive state for different isotopes. The investigations results of magnetic field influence on the carbon isotopes redistribution between carbon dioxide and disperse carbon in plasmachemical processes are given. Argon-oxygen plasma by a high-frequency generator was produced. Carbon placed into reaction zone by the high-frequency electrode evaporation. The plasmachemical reaction products quenching in the plasma flow at the sampler probe were examined. It is found that the Laval nozzle sampler is more efficient for plasma stream cooling versus the cylindrical sampler. The effects of flow rate, pressure and carbon dioxide concentration on the plasma flow cooling efficiency were estimated.

Abstract: The experimental study of the structure of commercially pure titanium after saturation with hydrogen from the gas phase by means of positron lifetime spectroscopy (PLS) and Doppler broadening spectroscopy (DBS) was carried out. In the result of penetration and accumulation of hydrogen, significant changes of annihilation characteristics occurred due to the defect structure changing. The investigated samples contained hydrogen in concentrations varying from 0 to 0.961 wt.%. Several stages of hydrogen interaction with the metal structure were revealed.

Abstract: The short analysis of the assessment opportunities is presented for the resource efficiency in various industries and particularly in the foundry production. The developed algorithm of carrying out such assessment is presented. It is shown that such algorithm consists of five steps. They are the formation of the evaluating team, the choice of the technology or a product, the analysis of the chain creation of the added value for a technology or a product, the assessment of the current state of the technology or a product, developing the recommendations for the improvement of the efficiency of resources use. This article describes in detail the works, which need to be carried out at each stage of evaluating the resource efficiency. The evaluating map and the criteria are developed for comparing different types of the foundry technologies as well as the map for assessing the current state of the foundry technology. The result of the accomplished assessment with the described algorithm is the developed recommendations on the use of the enterprise resources.

Abstract: By pulse magnetron deposition method the heat-shielding coatings on the basis of Zr-Y-O/ Si-Al-N layers on copper substrate are formed. Surface layer of copper substrate was treatment by the Zr⁺ ions. Structure-phase states were investigated by TEM, SEM, X-ray and SIMS. Thermal cycle durability of coatings is defined.

Abstract: This work is devoted to the study of copper ion positions in zeolite matrices. Copper cations were exchanged in mordenite and zeolite X from aqueous solutions of different copper salts varying their concentrations. Electronic state of copper in ion-exchanged samples exchanged and dried at different temperatures was evaluated by XPS spectroscopy. Depending on conditions of exchange treatment copper was found to be distributed between two different accessible sites in zeolites. These copper ions are stabilized as isolated species with well-defined oxygen coordination polyhedra.

Abstract: This paper is devoted to the studying of the dynamical changes in the density of aluminium microparticles (MPs) on the substrate surface made of stainless steel, immersed in vacuum arc plasma, at high-frequency short-pulse negative bias potential. It is shown experimentally that the density of aluminium MPs on the substrate surface is decreased dynamically by 3 orders when the treatment time is increased from 15 s to 3 min at the bias potential –2 kV. A possibility of the application of MPs unfiltered vacuum arc plasma for high-frequency short-pulse plasma immersion ion implantation to form the intermetallic layers is discussed.

Abstract: This paper reports on the use of nanopowders in the coating composition forms in casting blanks from lead bronzes for the petrochemical industry. Influence of composition of used protective separating coating of casting mold on the microstructure castings was investigated. For experimental investigations following coating were selected [1]: the mixture of zirconium dioxide nanopowder with industrial oil and the same composition as it’s, but on the basis of aluminum oxide nanopowder. As the test material multicomponent and lead bronzes were selected. The cooling curves castings using coatings of different compositions by means the developed device thermograph were constructed using techniques developed by the authors. The study results showed that the greatest reduction in the cooling rate at the time of crystallization bronze corresponds to coating casting mold based on powder of zirconium dioxide (45 °C/c). The cooling rate is reduced only to 65 °C/c when coating based on aluminum oxide. Decrease the cooling rate of castings using these coatings can change the shape and size of lead inclusions and align the casting structure in section. Form inclusions lead is becoming more spherical and their interfacial surface is leveled. The greatest changes occur in the surface layers of castings. Is shown that the multicomponent bronzes decreased speed the cooling due to the use plasters leads not only to changes in the morphology of inclusions but also to lead the change in the phase composition. Decrease of cooling rate leads to increasing the amount of eutectoid and growth of hardness casting.