Browsing by Author "Hsieh, Yu-Ping"

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Routing, ship size, and sailing frequency decision-making for a maritime hub-and-spoke container network
(2007-04-01)
Hsu, Chaug-Ing
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Hsieh, Yu-Ping
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運輸與物流管理系註：原交通所+運管所
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Department of Transportation and Logistics Management
This study formulates a two-objective model to determine the optimal liner routing, ship size, and sailing frequency for container carriers by minimizing shipping costs and inventory costs. First, shipping and inventory cost functions are formulated using an analytical method. Then, based on a trade-off between shipping costs and inventory costs, Pareto optimal solutions of the two-objective model are determined. Not only can the optimal ship size and sailing frequency be determined for any route, but also the routing decision on whether to route containers through a hub or directly to their destination can be made in objective value space. Finally, the theoretical findings are applied to a case study, with highly reasonable results. The results show that the optimal routing, ship size, and sailing frequency with respect to each level of inventory costs and shipping costs can be determined using the proposed model. The optimal routing decision tends to be shipping the cargo through a hub as the hub charge is decreased or its efficiency improved. In addition, the proposed model not only provides a tool to analyze the trade-off between shipping costs and inventory costs, but it also provides flexibility on the decision-making for container carriers. (c) 2006 Elsevier Ltd. All rights reserved.
Ruthenium substituted pyrochlore metal oxide catalysts Y2Ce2-xRuxO7-delta (x=0-0.4) for oxidative steam reforming of ethanol
(2020-07-31)
Hsieh, Ho-Chen
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Chen, Yun-Sheng
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Weng, Sheng-Feng
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Hsieh, Yu-Ping
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Lee, Chi-Shen
Metal oxides Y2Ce2-xRuxO7-delta (x = 0-0.4) with partial substitution of Run+ cations in the host structure were synthesized to study their catalytic activity on oxidative steam reforming of ethanol (OSRE). The samples were characterized using X-ray diffraction (XRD), X-ray photoelectron spectra (XPS) and temperature-programmed reduction (TPR). The performances investigated by varied temperatures, Ru ion content, carbon-to-oxygen ratios and long-term stability. The lowest activation temperature on OSRE is 300 degrees C, which is significantly lower than that of La2Ce2-xRuxO7-delta (400 degrees C). The cell dimension of Y2Ce2-xRuxO7-delta was reduced compare to La2Ce2-xRuxO7-delta for the replacement of the Y3+ ion with La3+ ion. The reduced unit cell in the host structure not only increase the surface composition of the Ce4+ ions, but also induce the synergetic effect of Run+/Ru4+ (n > 4) and Ce4+/Ce3+, which lead to the enhanced OSRE activity. The optimized catalyst Y2Ce1.6Ru0.4O7-delta showed selectivity of hydrogen S-H2 = 84(4)% (Y-H2 = 2.5(1) mol/mol EtOH) and carbon monoxide S-CO = 48(1)% for long-term stability test at T = 300 degrees C, C/O = 0.5, and O-2/C2H5OH = 1.5. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.