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One of the promising methods of detoxification is electrochemical reductive dehalogenation inorganic media (MeCN, DMSO) which has been thoroughly investigated during last decade [1-3].However for practical purpose much more promising and much less studied is direct cathodicdehalogenation of those substances in aqueous media.The main problem in this case is overwhelming concentration of water molecules which discharge inthe first place sharply decreasing current efficiency and consequently almost canceling practicalapplication perspectives. However when instead of common electrodes hydrophobic carbon cloth orcarbon felt electrodes were tried it allowed to reach promising results, especially when electrode wasmodified with catalytically active metal [4]. In this work dehalogenation on carbon cloth and Znmodifiedcarbon cloth cathodes in water and water-alcohol mixture was studied. A flow-circulationTeflon electrolytic cell with membrane and electrode areas of about 40 cm 3 and a flow rate of 40 mlmin -1 was used. 200 - 400 ml of initial aqueous solution of 1,1,1-trichlorethane (20mg/L) with0.05M Na2SO4 as a supporting electrolyte circulated through the cathode compartment separatedfrom the anode compartment by a cation exchange membrane (Thomapor MC-3470). Cationexchange membrane was used to avoid oxidative destruction of the substrate on the anode andchlorinating of the products by anodically formed Cl2. Aqueous solution of Na2SO4 (0.1M)circulated through anode compartment. During the course of electrolysis the solution in cathodecompartment was sampled and analyzed by GC/MS and Cl - -selective electrode.Results of experiments have shown that 1,1,1-trichlorethane can be completely destroyed on thecathode giving as a products ethane and ethylene with 1,1-dichlorethane and chlorethane as anintermediates. Direct electrochemical reduction of trichlorethane on a carbon cloth cathode wascarried out with average current efficiency up to 30%. The modification of a carbon cloth cathode byZn permits indirect electrocatalytic dechlorination and can be carried out with much betterefficiency. Electrolysis time can be reduced approximately two times with average current efficiencyup to 75%.References1. H. Lund & M. Baizer (1991). Organic Electrochemistry. Marcel Dekker, New York.2. S. Kulikov, V. Plekhanov, A. Tsyganok, C. Schlimm & E. Heitz (1996). Electrochimica Acta41(4): 527-5313. V. Plekhanov, O. Sharkova, S. Kulikov, A. Tsyganok (1997). Russian Journal of AppliedChemistry 70(10): 1561-15634. A. Tsyganok & K. Otsuka (1998). Electrochimica Acta 43(18): 2589-2596.48
O-29 NUMERICAL SIMULATION OF GALACTIC MERGERSJ. Lodenquai and C. McNamarahDepartment of Physics, MonaRadio-loud active galactic nuclei (AGNs) are elliptical galaxies that emit unusually largeamountsof non-thermal electromagnetic radiation (EMR) over a wide spectrum. The merger hypothesispostulates that an AGN can form from the merger of two spiral galaxies containing supermassiveblack holes in their cores.During merger, some amount of matter eventually falls onto each black hole, just outside itsSchwartzschild radius, forming an accretion disk. Differential rotation within the accretion diskresults in the transformation of a significant fraction of the mass of the disk into the EMR observedfrom AGNs.In this paper, the merger of spiral galaxies is studied numerically. Each spiral galaxy is assumed tohave (i) a spheroidal halo of dark matter (ii) a spiral disk consisting of stars and gas and (iii) aspheroidal nucleus containing stars and gas with a supermassive black hole of mass about ten millionsolar masses in its core. Previous simulations, which used simplified models [Bekki and Noguchi(1994), Bekki (1995)], claim to be able to explain the onset of AGN-behaviour during the merger.However, the present work does not find that the energetics of AGNs can be accounted for duringmerger. However, sufficient infalling matter onto the black holes could occur considerably later aftermerger.Videos of typical merger simulations are presented.ReferencesBekki, K. & Noguchi, M. (1994). Gas fueling to the central 10pc in merging galaxies. Astron.Astrophys. 290: 7-18.Bekki, K. (1995). Gas dynamics of the central 1 kpc in galaxy mergers. Mon. Not. R. Astron. Soc.276: 9-19.O-30 LIMITED AREA NUMERICAL ATMOSPHERIC MODELINGFOR THE EASTERN CARIBBEANM. Mayers, C. Depradine 1 and L. L. MoseleyDepartment of Computer Science, Mathematics and Physics, Cave Hill;1Caribbean Meteorological Institute, St. James, BarbadosThe objective of our research is to contribute to the development of a general limited areaatmospheric model appropriate to the Eastern Caribbean region. We will modify and extend existingmodels, where possible, to include phenomena ranging from weak tropical waves to hurricanes, andflooding due to rainfall, storm surge and wind generated waves. Current models are generally notwell tuned for our peculiar conditions.49
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