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Alexander Mukasyan |
Contact Information
Department of Chemical Engineering |
Tel: (574) 631-9825 |
MS |
Moscow Physical Engineering Institute, Russia |
1980 |
PhD |
Institute of Chemical Physics, RAS, Russia |
1986 |
DSc |
Institute of Structural Macrokinetics and Materials Science, RAS, Russia |
1994 |
Combustion of Heterogeneous Systems
Synthesis of Advanced Materials
Kinetics of Rapid High-Temperature Reactions
Inorganic Membranes
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Research interests of Professor Mukasyan are in fundamental studies of mechanisms for rapid high-temperature heterogeneous reaction and in developing of novel approaches for materials synthesis. The following fundamental topics are currently under investigation. Combustion in Microgravity Combustion in variety of gasless heterogeneous reaction systems is typically characterized by high temperatures (2000-3500 K) and heating rates (up to 106K/s). These conditions generate liquids and gases, which are subject to gravity-driven flow. The removal of such gravitational effects is likely to provide increased control of the reaction front, with a consequent improvement in control of the process. Thus on the one hand, microgravity experiments (NASA Glenn Research Center, Cleveland, OH) lead to major advances in the understanding of fundamental aspects of the combustion wave. On the other hand, the specific features of microgravity environment allow one to produce unique combustion products, which cannot be obtained under terrestrial conditions. Mechanisms of Heterogeneous Reaction Waves Propagation In these studies we address several important issues related to mechanisms of rapid high temperature heterogeneous reactions, both on the macro- and microscopic levels. They include studies on the microstructural features of combustion wave propagation in gasless systems, examined with time scale ?10-3 s and length scale 1-100 mm. For this purpose we have developed a novel technique of digital high-speed microscopic video recording (DHSMVR), which allows in-situ observation of rapid processes occurring at the microscopic level. This technique is applied to investigate high temperature reaction waves in a variety of reaction systems. Using this method, significantly new information about the microstructure of gasless combustion waves was obtained, and a new basis was created for understanding the mechanisms of fast chemical reactions in heterogeneous media. Also several industries related projects involve: Combustion Synthesis (CS) of Advanced Materials The synthesis of materials using combustion phenomena is an advanced approach in powder metallurgy. The process is characterized by unique conditions involving high temperatures (up to 3,500 K), and short reaction times (on order of seconds). As a result, combustion methods offer several attractive advantages over conventional metallurgical processing and alloy development technologies. The foremost is that solely the heat of chemical reaction (instead of an external source) supplies the energy for the synthesis. Also, simple equipment, rather than energy-intensive high-temperature furnaces, is sufficient. Further, an attractive aspect of combustion process is its ability to produce materials of hih-purity, since the high temperatures purge the powders of any volatile impurities adsorbed or present in the reactants. Remarkably, the high temperature gradients, combined with rapid cooling rates in the combustion wave, may form metastable phases and unique microstructures not possible by conventional methods. In addition, this technique allows the synthesis of new alloy compositions conveniently, rapidly, and in relatively small amounts that permit rapid screening of material composition to enhance properties. Finally, the combustion method also permits scale-up, so that commercial quantities can be produced efficiently. Currently we work on developing of two CS-based technologies, i.e. casting bio-alloys for direct production of orthopedic implants (special presentation #3) and sintering of complex oxide membranes for solid fuel cell applications (special presentation #4) . Non-isothermal Kinetics This problem is important because in a majority of chemical engineering processes, the reaction system should be preheated before it reaches isothermal conditions or it operates under conditions where temperature changes with time. Some qualitative results available in the literature indicate that temperature-time history of the reactants may influence the mechanisms of chemical reactions. Thus, it is critical to know: (i) to what extent does the behavior of the reaction system depend on heating rate; (ii) whether one can use kinetics obtained under isothermal conditions to describe the reaction occurring essentially non-isothermally. High-Toughness Carbon-Carbon Composites Current technology of carbon-carbon brake production involves several cycles of CVI/CVD processes to transform initially high porous carbon fiber substrate to dense materials (>1.7 g/cc). One of the disadvantages of this approach is a long manufacturing time (~120 days). Other way to obtain dense graphite material with the required friction properties is to sintered carbon mesophase. It was shown that in general mesocarbon can be rapidly (1-2 days) sintered into essentially fully dense materials under relatively low processing temperature (<1500 C). However the toughness of synthesized materials is far below critical and thus after few stops samples usually broke in a brittle failure mode. The goal of the project is, based on fundamental studies of sintering mechanism and using different "reinforcement" approaches, to elaborate the "rapid" technology for processing of mesocarbon microbeads (MCMB) to high-toughness composite carbon-based materials. Carbon Nano-Tubes (CNT) Carbon nanotubes currently attract great attention owing to their unique characteristics, such as high strength, electrical conductivity, as well as special functional properties. For example, CNTs have high potential for use as hydrogen storage materials in the transportation sector, electrochemical hydrogen storage in electrodes of rechargeable batteries and fuel cells and field emission materials in display technology. Among other methods for CNT synthesis the floating catalyst (FC) approach, used in our laboratory, is most promising, because of its possibility for continuous production of pure CNTs, simple equipment, low reaction temperature and thus low cost. Currently we are working on identifying the mechanism of CNT synthesis, and more specifically on the influence of catalytic agent nature on the microstructure and properties of the synthesized nanotube. Thin Dense Metal Films Nanoscale grained dense thin metallic films are of great importance in a variety of scientific and technological fields including microelectronics, optical devices, catalysis, chemical and biological sensors. A number of techniques are used for synthesis of the films, such as atomic layer epitaxy, magnetron sputtering, chemical vapor deposition and electroless plating. The properties of the films depend significantly on the microstructure and thickness. However, the available synthesis techniques, while yielding different microstructure and thickness, do not permit a systematic variation of these parameters in order to optimize film properties. We have developed a novel approach to overcome this problem and synthesize thin (~1 mm) fully dense film with nanoscale grained microstructure. This technique is an unusual combination of two different phenomena: electroless plating and osmosis. Since this unique approach can be used for synthesis of nanograined thin metal films of any desired composition, it can be employed in a variety of applications. See selected publications for more details regarding above noted directions (see also full list of publications): A.S. Mukasyan, C. Lau, and A. Varma., 2004, Review: "Influence of Gravity on Combustion Synthesis of Advanced Materials, AIAA Journal, vol. 42, (8). A. Varma, and A. S. Mukasyan, A. 2004, Combustion Synthesis of Advanced Materials: Fundamentals and Applications, Korean J. Chem. Eng., 21 (2), 527-536. C. Norfolk, Mukasyan, A.S. Hayes D., McGinn P., and Varma A., 2003 "Processing of Mesocarbon Microbeads to High-Performance Materials: Part I. Studies Toward the Sintering Mechanism. Carbon, 42 (1), 11-19. B. Li, A.S. Mukasyan, and A. Varma, 2003, Combustion Synthesis of CoCrMo (F-75) Implant Alloys: Microstructure and Properties", Mater. Res. Inov, 7 (4) 245-252. A. Varma, Mukasyan A. S, Deshpande K., Pranda P., Erii, P., 2003, Combustion Synthesis of Nanoscale Oxide Powders: Mechanism, Characterization and Properties, Mat. Res. Soc. Symp. Proc. Vol. 800, 113-124. C. Lau, Mukasyan A.S. and A. Varma, 2002, "Materials Synthesis by Reduction-Type Combustion Reaction: Influence of Gravity, Proceedings Combustion Institute, 29, 1101-1108. A. Varma, "K. L. Yeung, R. Souleimanova and A.S. Mukasyan, 2002, Novel Approach for Thin Dense Nanoscale Grained Metal Films, Ind. & Eng. Chem. Res., 41 (25), 6323-6325. A. Varma, A., Li, B. and A. Mukasyan, 2002, Novel Synthesis of Orthopaedic Implant Materials, J. Adv. Eng." Mater., 4, (7), 482-487. A.S. Mukasyan, C. Lau and A. Varma. 2001. Gasless Combustion of Aluminum Particles Clad by Nickel. Combust. Sci. Tech., 170:67-85. I.A. Filimonov, Ni.I. Kidin. and A.S. Mukasyan. 2001. The Influence of Filtration and Reactant Gas Pressure on Spin Combustion in Gas-Solid System. Int. J. SHS, 10:151-176. C. Lau, A.S. Mukasyan, A. Pelekh and A. Varma. 2001. Combustion Synthesis of NiAl-based Composite: Effects of Microgravity. J. Mat. Sci. Res. 16:1614-1625. A. S. Mukasyan, C. Costello, K.P. Sherlock, D. Lafarga and A.Varma. 2001. Perovskite Membranes by Aqueous Combustion Synthesis: Synthesis and Properties. Sep. & Purif. Tech., 25:117-126. R. Souleimanova, R., A.S. Mukasyan and A. Varma. 2000. Effects of Osmosis on Microstructure of Pd-Composite Membranes Synthesized by Electroless Plating Technique. J. Memb. Sci., 166:249-257. A.S. Mukasyan, A.S. Rogachev and A. Varma. 2000. Microstructural Mechanism of Combustion in Heterogeneous Reaction Media. Proceed. Combustion Institute, 28:1413-1419. A. Pelekh, A.S. Mukasyan and A. Varma. 2000, Electrothermography apparatus for kinetics of rapid high-temperature reactions", Rev. Sic. Instrum.,71:220-223 L. Thiers, B. Leitenberger, A.S. Mukasyan and A. Varma. 2000. Influence of Preheating Rate on Kinetics of High-Temperature Gas-Solid Reactions", AIChE Journal, 46:2518-2524. A.S. Mukasyan, A.S. Rogachev and A. Varma. 1999. Microscopic Mechanisms of Pulsating Combustion in Gasless Systems. AIChE Journal, 45:2580-2585. A.S. Mukasyan, A.S. Rogachev and A. Varma. 1999. Mechanism of Reaction Wave Propagation during Combustion Synthesis of Advanced Materials. Chem. Eng. Sci., 54:3357-3367. A. Varma, A.S. Rogachev, A.S. Mukasyan and S. Hwang. 1998.Complex Behavior of Self-Propagated Reaction Waves in Heterogeneous Media. Proc. Natl. Acad. Sci. USA, 95:11053-11058. A. Varma, A.S. Rogachev, A.S. Mukasyan and S. Hwang. 1998. Review: Combustion Synthesis of Advanced Materials: Principles and Applications. Advances in Chemical Engineering, 24:79-226. |
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