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Hung C.,Yung Ta Institute of Technology and Commerce
Journal of Hazardous, Toxic, and Radioactive Waste | Year: 2011

The behavior of the ammonia (NH3) oxidation was studied by selective catalytic oxidation (SCO) over a Pt-Pd-Rh nanocomposite cordierite catalyst in a tubular fixed-bed flow quartz reactor at temperatures between 423 and 623 K. The catalysts' surface properties were characterized using scanning transmission electron microscopy-energy-dispersive X-ray, optical microscopy, and ultraviolet visible. The experimental results show that high activities for NH3 removal were achieved during catalytic oxidation over the Pt-Pd-Rh cordierite catalyst at 623 K with an oxygen content of 4%. N2 was the main product in the NH3-SCO process over the Pt-Pd-Rh nanocomposite cordierite catalyst. These results also verify the Pt-Pd-Rh metals on cordierite surfaces, resulting in the formation of catalytically active sites at the metal-support interface in the reduction of NH3 in this process. In addition, the Pt-Pd-Rh nanocomposite cordierite-induced cytotoxicity testing was mainly applied to the human lung MRC-5 cell line, and the percentage of cell survival was determined by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium analysis in vitro. For Pt-Pd-Rh nanocomposite cordierite, only minor cytotoxicity was observed when human lung cells were exposed. © 2011 ASCE. Source

Hung C.-M.,Yung Ta Institute of Technology and Commerce
Powder Technology | Year: 2012

This study elucidates the electrocatalytic oxidation (ECO) of ammonia (NH 3) over a complex PtPdRh nanoparticle electrocatalytic material immersed in a 0.5-M H 2SO 4 solution, where the electrolyte was measured using a linear sweep voltammogram (LSV) technique. The complex PtPdRh nanoparticle electrode was synthesized from H 2PtCl 6, Pd(NO 3) 3 and Rh(NO 3) 3 and deposited on an alumina substrate to improve the NH 3-ECO ability. The experimental data indicate that a high ECO activity was achieved during the catalytic oxidation over the PtPdRh electrocatalytic material when using a high potential sweep rate; the maximum current density reached for the NH 3 oxidation was 0.4mA in the voltage range of 0.1V. Interesting, this LSV oxidation ability may explain the significant activity of the catalyst in an acidic environment. The catalyst structure was characterized by polarization curves, UV-vis, three-dimensional excitation-emission fluorescent matrix (EEFM) spectroscopy and TEM. EEFM was applied to evaluate the fresh catalyst yields for the fluorescent plots of 220/345nm and 210/385nm, and TEM determined the particle size of the nanoparticles and indicated a high dispersion phenomenon had occurred. © 2012 Elsevier B.V. Source

Wei P.S.,National Sun Yat - sen University | Wu T.H.,Yung Ta Institute of Technology and Commerce
International Journal of Heat and Mass Transfer | Year: 2012

The effects of local electrical contact resistance on transport variables, cooling rate, solute distribution, and nugget shape after solidification responsible for microstructure of the fusion zone during resistance spot welding are realistically and systematically investigated. The model accounts for electromagnetic force, heat generation and contact resistances at the faying surface and electrode-workpiece interfaces and bulk resistance in workpieces. Contact resistances are composed of film and constriction resistances, as functions of hardness, temperature, electrode force and surface condition. The computed results show that the bulk dynamic electrical resistance cannot reliably reflect transport processes and nugget shape, unless the local constriction resistance and electric current density are known. Regardless of high film resistance, nugget growth and transport processes are independent of film resistance due to delayed response time of local electric current in the early stage. A decrease in constriction resistance, however, delays nugget formation, enhances convection and solute mixing, and changes circulation direction of the stronger convection cell during cooling period. © 2012 Elsevier Ltd. All rights reserved. Source

This work describes the oxidation of ammonia (NH3) at temperatures between 423 and 673K by selective catalytic oxidation (SCO) over a Pt-Rh nanocomposite catalyst that was prepared by the co-precipitation of H2PtCl6 and Rh(NO3)3 in a tubular fixed-bed flow quartz reactor (TFBR). The catalysts were characterized using TEM, XRD, PSA, and CV. The experimental results reveal that at a temperature of 673K and an oxygen content of 4%, approximately 98% of the NH3 was removed by catalytic oxidation over the Pt-Rh nanocomposite catalyst. N2 was the main product of the NH3-SCO process. The Pt-Rh nanocomposite-induced cytotoxicity to the human lung cell line, MRC-5, was tested, and cell survival was determined using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetra-zolium (MTS) analysis in vitro. These results demonstrated that the Pt-Rh nanocomposite catalyst is only weakly cytotoxic to human lung cells. © 2011 Elsevier B.V. Source

Liang J.S.,Yung Ta Institute of Technology and Commerce
Computers in Industry | Year: 2010

This study describes the generation of Web-based troubleshooting system for automotive refrigeration system using knowledge engineering approach over the Internet. The relevant technologies used in the system are discussed in detail. The aim of the proposed knowledge-based troubleshooting system (KBTS) is to integrate the troubleshooting process of automotive refrigeration system into a single architecture for retrieving knowledge and experience of technicians in automobile repairing field. The application of KBTS guides the novice or learner through different stages of the troubleshooting process enabling the creation of problem-solving list, its contents include the selection of hand tools and instrument, decision of detecting methods, procedure of disassembling/reassembling component, adjusting, and so on. Through the use of web and knowledge approach, the troubleshooting knowledge of automobile refrigeration system can be effectively incorporated into the procedure generation framework and a Web-based troubleshooting procedure generation system can also be implemented. © 2009 Elsevier B.V. All rights reserved. Source

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