Перегляд за Автор "Mamalis, A. G."
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Документ 3D simulation of diamond grinding process by finite element method(НТУ "ХПИ", 2011) Mamalis, A. G.; Grabchenko, A. I.; Fedorovich, V. A.; Kundrak, J.; Babenko, A. E.Process of manufacture of diamond wheels on various bonds is characterized by high labour content and low productivity, high consumption of expensive diamond grains and, as consequence, the high cost price of a further operational process of diamond wheels. It is necessary to attain reliability and quality heightening at diamond-abrasive tool manufacture without which its effective application in production is impossible. Production of diamond - abrasive tool is founded on establishment of physical and technological regularities of sintering process of diamond-bearing layer. Now there are no scientifically based recommendations for choice of the rational combinations of strength, brand of grain, graininess, concentration with the physical-mechanical properties of bonds. The aim of given research is the development of the technique of the theoretical definition of an optimal combination of strength properties of diamond grains and bond at which ones retention of diamond grain integrity at the process of manufacture of diamond wheel is ensured by using 3D simulations of deflected mode of sintering area of its diamond-bearing layer.Документ The analysis of tasks of development and reengineering process of reliability computer networks for critical technologies(NTU "KhPI", 2009) Elyasi-Komari, I.; Mamalis, A. G.; Lavrynenko, S. N.The analysis of tasks of development and reengineering of computer networks of information-control (I&C) systems of critical technologies (CT) using opened network technologies and the commercial network equipment is executed. Formal tasks of development and reengineering of computer networks I&C systems of CT are formulated and the initial data, necessary for their decision are analyzed. The principles of profile formation bases of the computer networks based on open standards, variants of a network structure and their choice are considered in view of the requirements showed to reliability, quality of service, to functional and other characteristics of computer networks. These procedures can be realized as the tool utilities, which allowing to automate the process of computer systems designing.Документ Development of modular machine design and technologies of dynamic action for finishing-grinding treatment by an oscillating abrasive medium(Nova Science Publishers, Inc., 2015) Mamalis, A. G.; Kundrak, J.; Mitsyk, A. V.; Fedorovich, V. A.A complex approach is proposed to designing machines and technologies for finishinggrinding treatment of complex-shaped parts by an oscillating fine-dispersed abrasive medium. A designed element base has been developed for the design-technological synthesis of the autonomously controlled actuating mechanisms in the form of the device with the processed parts and the reservoir, combined into a single aggregate modular machine. The field of combining schemes of the power actions on an abrasive medium and processed parts has been considered.Документ Diamond biocompatible coatings for medical implants(Collegium Basilea & AMSI, 2016) Starikov, V. V.; Starikova, S. L.; Mamalis, A. G.; Lavrynenko, S. N.New carbon (diamond-like) nanocomposite coatings deposited from a C60 ionic beam can be used as a wear-resistant protective coating for implants. It was found that these coatings enhance resistance to тelectrochemical corrosion processes due to a shift of the material’s electrode potential to a zone of positive values. They also promote a complex of reparative, adaptative and compensatory reorganization that accelerates the healing processes in the vicinity of the implant.Документ Features of medical implant passivation using anodic oxide films(Collegium Basilea & AMSI, 2016) Starikov, V. V.; Starikova, S. L.; Mamalis, A. G.; Lavrynenko, S. N.The passivation ability of metals from groups IV and V of the Periodic Table is considered. Anodic treatment is able to neutralize the increase of metal hardening when comminuting grains to nanometre sizes. The deposition of metal oxide film coatings on a cobalt–chromium alloy surface results in substantial passivation of its surface and prevents cobalt and chromium accumulation in bone tissues. The decrease of surface activity of titanium implants can be achieved both by cleaning the surface during vacuum annealing before oxidation and by the increase of the anodic oxide film thickness, which limits mass and charge transfer through the implant surface. Recommended titanium implant treatment regimens are vacuum annealing at 650 °C and anodic oxidation to attain an oxide thickness less or equal to 300 nm.Документ Improving the Design of Diamond Wheel for High-Speed Grinding(Nova Science Publishers, Inc., 2016) Mamalis, A. G.; Grabchenko, A. I.; Fedorovich, V. A.; Romashov, D. V.Grinding at high speeds is a complex process requiring specific tools for successful use. Rotational stresses during high-speed grinding can lead to failure if the wheel is not correctly designed. These results are extremely difficult to be obtained during a large number of field experiments due to the high cost of testing equipment. So, the article describes ways of improving the integrity of the body of the diamond grinding wheel for high-speed regimes using analytical approaches and finite element method.Документ Mathematical simulation of motion of working medium at finishing-grinding treatment in the oscillating reservoir(Springer-Verlag London, 2014) Mamalis, A. G.; Grabchenko, A. I.; Mitsyk, A. V.; Fedorovich, V. A.; Kundrak, J.The results of mathematical simulation have been carried out for the pattern of working medium motion providing the technological process of finishing–grinding treatment in an oscillating reservoir. With use of physics laws, it is ascertained and grounded that the flow of granules at the plane wall of reservoir is travelling oppositely to the source of vibrations, whereas the granules are drifting on the cycloid–trochoid trajectories from the wall of reservoir, where the looped displacement is maximal, to the center of reservoir in which the shift of granules is reduced to minimum because of damping and dissipation effect. The received theoretical regulations have a fundamental nature and can be used at the account of technological parameters of designed vibration machines.Документ A novel concept for the manufacture of individual sapphire-metallic hip joint endoprostheses(Collegium Basilea & AMSI, 2006) Mamalis, A. G.; Ramsden, J. J.; Grabchenko, A. I.; Lytvynov, L. A.; Filipenko, V. A.; Lavrynenko, S. N.At the present time, artificial joints made with metallic, ceramic, metal-polymeric or ceramic polymeric friction pairs substituting for the natural biomechanic articulations "head of the hip joint-acetabulum" are widely used for endoprosthetic operations on hip joints. Experience gained in the course of more than 2000 operations has shown that along with the advantageous properties of modern endoprosthetic constructions made of metal, ceramics and polymers, they have certain drawbacks. Among them are insufficient biological inertness and susceptibility to excessive wear of the friction pair components. In addition, as a result of wear of the hinge friction pair, toxic and oncologically dangerous products of degradation accumulate in the different organs and tissues. This in turn results in severe complications and demands correspondingly complicated corrective intervention, often leading to worse disability than that which the original operation was designed to cure. The aim of the study reported here was the development and clinical validation of a highly effective and long-lived hip joint endoprosthesis with a sapphire head whose wear capacity is superior to all others. The endoprosthesis consists of a metallic pedicle, a dismountable articulation (metallic necklayer of supramolecular polyethylene sapphire head) and an acetabular cup. The endoprostheses with the sapphire head proved themselves positively in clinical trials and are considered to be highly promising for future applications.Документ Properties of magnetron hydroxyapatite coatings deposited on oxidized substrates(Collegium Basilea & AMSI, 2016) Starikov, V. V.; Kostuchenko, A. V.; Starikova, S. L.; Mamalis, A. G.; Lavrynenko, S. N.Hydroxyapatite (HA) coating were formed on oxidized niobium surfaces by the highfrequency magnetron sputtering method using hydroxyapatite and tricalcium phosphate targets. The structure, substructure and mechanical properties of the Nb–Nb2O5–HA system were investigated by X-ray diffraction, atomic force microscopy and nanoindentation and the stress state was assessed. The synthesized hydroxyapatite film had the following characteristics: thermal expansion coefficient 10–5 K–1; modulus of elasticity 120 GPa; adhesive strength not less than 0.45 kg/mm2; density 2900 kg/m3. The stress magnitude in the metal oxide substrate was from 11 to 14 MPa after hydroxyapatite film deposition.Документ Simulation of effects of metal phase in a diamond grain and bonding type on temperature in diamond grinding(Springer-Verlag London, 2012) Mamalis, A. G.; Grabchenko, A. I.; Fedorovich, V. A.; Kundrak, J.Manufacturing diamond wheels on various bonds is a relatively high-cost process, requiring high labour and high consumption of expensive diamond grains but yielding relatively low productivity. With better knowledge of the various factors involved in the sintering process, the most efficient combinations can be found, leading to higher productivity. Currently, there are no scientifically based recommendations for the choice of the rational combinations of strength, brand of grain, graininess and concentration with the physical–mechanical properties of bonds. The aim of this research is the development of a technique for the theoretical definition of an optimal combination of strength properties of diamond grains and bond to provide maximum retention of diamond grain integrity during the process of diamond wheel manufacture. This is investigated using 3D simulations of the deflected mode of the sintering area of the wheel's diamond bearing layer.Документ Stimulation of calcium phosphate crystal formation by implant surfaces with electret properties(Collegium Basilea & AMSI, 2015) Starikov, V. V.; Starikova, S. L.; Mamalis, A. G.; Lavrynenko, S. N.Oxide coatings with electret properties are investigated. The possibility of stimulation of the formation of calcium phosphate sediments near the electroactive surface is discussed. The exposure of implants with such coatings to solutions imitating blood plasma showed their high efficiency of biointegration due to activation of an exchange processes in living tissues by a negative superficial charge. The revealed effect amplifies with the growth of the thickness of the anodic oxide film.Документ Two-stage electro-discharge machining fabricating superhard cutting tools(Elsevier Inc., 2004) Mamalis, A. G.; Grabchenko, A. I.; Magazeev, M. G.; Krukova, N. V.; Prohàszká, J.; Vaxevanidis, N. M.A novel technique for fabricating efficiently precision cutting tools made from polycrystalline superhard materials is reported in the present paper. For this purpose, a two-stage electro-discharge machining (EDM) was applied on diamond polycrystallines, by employing first wire-electrode EDM for rough cutting and subsequently rotational disc-electrode EDM for finishing operations. Experimental results obtained clearly indicate the applicability of the proposed two-stage technique for fabricating precision cutting tools that can be used for the production of machined components made from glass and plastics, ceramics, composite materials and non ferrous metals, at an industrial scale.