The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Shuanglin Shen - One of the best experts on this subject based on the ideXlab platform.
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dynamic characteristics of local current densities and temperatures in proton exchange membrane fuel cells during Reactant starvations
International Journal of Hydrogen Energy, 2012Co-Authors: Guangsheng Zhang, Shuanglin ShenAbstract:Abstract Reactant starvation during proton exchange membrane fuel cell (PEMFC) operation can cause serious irreversible damages. In order to study the detailed local characteristics of starvations, simultaneous measurements of the dynamic variation of local current densities and temperatures in an experimental PEMFC with single serpentine flow field have been performed during both air and hydrogen starvations. These studies have been performed under both current controlled and cell voltage controlled operations. It is found that under current controlled operations cell voltage can decrease very quickly during Reactant starvation. Besides, even though the average current is kept constant, local current densities as well as local temperatures can change dramatically. Furthermore, the variation characteristics of local current density and temperature strongly depend on the locations along the flow channel. Local current densities and temperatures near the channel inlet can become very high, especially during hydrogen starvation, posing serious threats for the membrane and catalyst layers near the inlet. When operating in a constant voltage mode, no obvious damaging phenomena were observed except very low and unstable current densities and unstable temperatures near the channel outlet during hydrogen starvation. It is demonstrated that measuring local temperatures can be effective in exploring local dynamic performance of PEMFC and the thermal failure mechanism of MEA during Reactants starvations.
Juinndar Huang - One of the best experts on this subject based on the ideXlab platform.
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ISVLSI - Multi-target Many-Reactant Sample Preparation for Reactant Minimization on Microfluidic Biochips
2018 IEEE Computer Society Annual Symposium on VLSI (ISVLSI), 2020Co-Authors: Juinndar HuangAbstract:Sample preparation is one of essential steps in biochemical applications. It produces solutions with target concentrations through mixing various Reactants in a specific way. In this paper, we propose a Reactant cost minimization technique, M2SPA, for multi-target many-Reactant sample preparation on microfluidic biochips through maximally sharing identical intermediate solutions among different targets. M2SPA first represents target concentrations as a recipe cube, searches all feasible candidates for intermediate solution sharing among targets, and then selects the one with the best cost saving for action. Experimental results show that the proposed algorithm can reduce up to 15.7% of Reactant cost as compared to a state-of-the-art method.
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Reactant Minimization in Sample Preparation on Digital Microfluidic Biochips
IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 2015Co-Authors: Tingwei Chiang, Juinndar HuangAbstract:Sample preparation plays an essential role in most biochemical reactions. Raw Reactants are diluted to solutions with desirable concentration values in this process. Since the Reactants, like infant’s blood, DNA evidence collected from crime scenes, or costly reagents, are extremely valuable, their usage should be minimized whenever possible. In this paper, we propose a two-phased Reactant minimization algorithm (REMIA), for sample preparation on digital microfluidic biochips. In the former phase, REMIA builds a Reactant-minimized interpolated dilution tree with specific leaf nodes for a target concentration. Two approaches are developed for tree construction; one is based on integer linear programming (ILP) and the other is heuristic. The ILP one guarantees to produce an optimal dilution tree with minimal Reactant consumption, whereas the heuristic one ensures runtime efficiency. Then, REMIA constructs a forest consisting of exponential dilution trees to produce those aforementioned specific leaf nodes with minimal Reactant consumption in the latter phase. Experimental results show that REMIA achieves a reduction of Reactant usage by 32%–52% as compared with three existing state-of-the-art sample preparation approaches. Besides, REMIA can be easily extended to solve the sample preparation problem with multiple target concentrations, and the extended version also effectively lowers the Reactant consumption further.
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sample preparation for many Reactant bioassay on dmfbs using common dilution operation sharing
International Conference on Computer Aided Design, 2013Co-Authors: Haohan Chang, Tungche Liang, Juinndar HuangAbstract:Sample preparation is an essential processing step in most biochemical applications. Various Reactants are mixed together to produce a solution with the target concentration. Since Reactants generally take a notable part of the cost in a bioassay, their usage should be minimized whenever possible. In this paper, we propose an algorithm, CoDOS, to prepare the target solution with many Reactants using common dilution operation sharing on digital microfluidic biochips (DMFBs). CoDOS first represents the given target concentration as a recipe matrix, and then identifies rectangles in the matrix, where each rectangle indicates an opportunity of dilution operation sharing for Reactant minimization. Experimental results demonstrate that CoDOS can achieve up to 27% of Reactant saving as compared with the bit-scanning method in single-target sample preparation. Moreover, even if CoDOS is not developed for multi-target sample preparation, it still outperforms the recent state-of-the-art algorithm, RSMA. Hence, it is convincing that CoDOS is a better alternative for many-Reactant sample preparation.
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Reactant and waste minimization in multitarget sample preparation on digital microfluidic biochips
IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 2013Co-Authors: Juinndar HuangAbstract:Sample preparation is one of essential processes in biochemical reactions. Raw Reactants are diluted in this process to achieve given target concentrations. A bioassay may require several different target concentrations of a Reactant. Both the dilution operation count and the Reactant usage can be minimized if multiple target concentrations are considered simultaneously during sample preparation. Hence, in this paper, we propose a multitarget sample preparation algorithm that extensively exploits the ideas of waste recycling and intermediate droplet sharing to reduce both Reactant usage and waste amount for digital microfluidic biochips. Experimental results show that our waste recycling algorithm can reduce the waste and operation count by 48% and 37%, respectively, as compared to an existing state-of-the-art multitarget sample preparation method if the number of target concentrations is ten. The reduction can be up to 97% and 73% when the number of target concentrations goes even higher.
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graph based optimal Reactant minimization for sample preparation on digital microfluidic biochips
International Symposium on VLSI Design Automation and Test, 2013Co-Authors: Tingwei Chiang, Juinndar HuangAbstract:Sample preparation is an essential step in biochemical reactions. Reactants must be diluted to achieve given target concentrations in sample preparation. Since some Reactants like costly reagents and infant's blood are valuable, their usage should be minimized during dilution. In this paper, we propose an optimal Reactant minimization algorithm, GORMA, for sample preparation on digital microfluidic biochips. GORMA adopts a systematic method to exhaustively check all possible dilution solutions and then identifies the one with minimal Reactant usage and waste through maximal droplet sharing. Experimental results show that GORMA outperforms all the existing methods in Reactant usage. Meanwhile, the waste amount is reduced up to 30% as compared with existing waste minimization methods. Moreover, GORMA requires only 0.6% more operations on average when compared with an operation-minimal dilution method.
Eva M Nilsson - One of the best experts on this subject based on the ideXlab platform.
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compact mixed Reactant fuel cells
Journal of Power Sources, 2002Co-Authors: Michael A Priestnall, Vega P Kotzeva, Deborah J Fish, Eva M NilssonAbstract:Abstract The compact mixed-Reactant (CMR) fuel cell is an important new “platform” approach to the design and operation of all types of fuel cell stacks. Amongst several other advantages, CMR has the potential to reduce polymer electrolyte membrane (PEM) stack component costs by around a third and to raise volumetric power densities by an order of magnitude. Mixed-Reactant fuel cells, in which the fuel and oxidant within a cell are allowed to mix, rely upon the selectivity of anode and cathode electrocatalysts to separate the electrochemical oxidation of fuel and reduction of oxidant. A comprehensive review of the 50-year history of mixed-Reactant literature has demonstrated that such systems can perform as well as and, in some circumstances, much better than conventional fuel cells. The significant innovation that Generics has introduced to this field is to combine the concept of mixed-Reactant fuel cells with that of a fully porous membrane electrode assembly (MEA) structure. Passing a fuel–oxidant mixture through a stack of porous cells allows the conventional bipolar flow-field plates required in many fuel cell designs to be eliminated. In a conventional PEM stack, for example, the bipolar carbon flow-field plates may block up to half of the active cell area and account for up to 90% of the volume of the stack and of the order of one-third of the materials costs. In addition to all the advantages of mixed-Reactant systems, the “flow-through” mode, embodied in Generics’ CMR approach, significantly enhances mass-transport of Reactants to the electrodes and can reduce Reactant pressure drops across the stack. Redesigning fuel cells to operate in a CMR mode with selective electrodes offers the attractive prospect of much reduced stack costs and significantly higher stack power densities for all types of fuel cell. Initial modeling and proof of principle experiments using an alkaline system have confirmed the validity of the CMR approach and the potential for substantial performance improvements.
Guangsheng Zhang - One of the best experts on this subject based on the ideXlab platform.
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dynamic characteristics of local current densities and temperatures in proton exchange membrane fuel cells during Reactant starvations
International Journal of Hydrogen Energy, 2012Co-Authors: Guangsheng Zhang, Shuanglin ShenAbstract:Abstract Reactant starvation during proton exchange membrane fuel cell (PEMFC) operation can cause serious irreversible damages. In order to study the detailed local characteristics of starvations, simultaneous measurements of the dynamic variation of local current densities and temperatures in an experimental PEMFC with single serpentine flow field have been performed during both air and hydrogen starvations. These studies have been performed under both current controlled and cell voltage controlled operations. It is found that under current controlled operations cell voltage can decrease very quickly during Reactant starvation. Besides, even though the average current is kept constant, local current densities as well as local temperatures can change dramatically. Furthermore, the variation characteristics of local current density and temperature strongly depend on the locations along the flow channel. Local current densities and temperatures near the channel inlet can become very high, especially during hydrogen starvation, posing serious threats for the membrane and catalyst layers near the inlet. When operating in a constant voltage mode, no obvious damaging phenomena were observed except very low and unstable current densities and unstable temperatures near the channel outlet during hydrogen starvation. It is demonstrated that measuring local temperatures can be effective in exploring local dynamic performance of PEMFC and the thermal failure mechanism of MEA during Reactants starvations.
Haruhiko Ohya - One of the best experts on this subject based on the ideXlab platform.
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development of porous solid Reactant for thermal energy storage and temperature upgrade using carbonation decarbonation reaction
Applied Energy, 2001Co-Authors: Masahiko Aihara, Toshiyuki Nagai, Junro Matsushita, Yoichi Negishi, Haruhiko OhyaAbstract:Cyclic reaction performances of solid Reactants for a CaO-CO2 chemical heat-pump designed for upgrading and storing high-temperature thermal energy were studied. Solid Reactants composed of CaO as the Reactant and CaTiO3 as the inert framework were prepared using the conventional powder method or the metal alkoxide method. Upon experiments of cyclic operation between CaO carbonation and CaCO3 decarbonation at 1023K, the reaction reversibility of the solid Reactants with the inert CaTiO3 framework was steady, whereas that of the solid Reactant without the inert framework decreased with sintering of the solid particles during cyclic operation. Reaction rates for the first carbonation and the decarbonation of solid Reactant prepared using the alkoxide method were about 1.8 and 2.4 times faster, respectively, than for those prepared by the powder method due to the smaller average diameter of Reactant particles derived from the alkoxide method.
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Development of porous solid Reactant for thermal-energy storage and temperature upgrade using carbonation/decarbonation reaction
Applied Energy, 2001Co-Authors: Masahiko Aihara, Toshiyuki Nagai, Junro Matsushita, Yoichi Negishi, Haruhiko OhyaAbstract:Cyclic reaction performances of solid Reactants for a CaO-CO2 chemical heat-pump designed for upgrading and storing high-temperature thermal energy were studied. Solid Reactants composed of CaO as the Reactant and CaTiO3 as the inert framework were prepared using the conventional powder method or the metal alkoxide method. Upon experiments of cyclic operation between CaO carbonation and CaCO3 decarbonation at 1023K, the reaction reversibility of the solid Reactants with the inert CaTiO3 framework was steady, whereas that of the solid Reactant without the inert framework decreased with sintering of the solid particles during cyclic operation. Reaction rates for the first carbonation and the decarbonation of solid Reactant prepared using the alkoxide method were about 1.8 and 2.4 times faster, respectively, than for those prepared by the powder method due to the smaller average diameter of Reactant particles derived from the alkoxide method.
