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Full-Text Articles in Chemical Engineering
Fast Measurements Of Flow Through Mitral Regurgitant Orifices With Magnetic Resonance Phase Velocity Mapping, Haosen Zhang, Sandra S. Halliburton, Richard D. White, George P. Chatzimavroudis
Fast Measurements Of Flow Through Mitral Regurgitant Orifices With Magnetic Resonance Phase Velocity Mapping, Haosen Zhang, Sandra S. Halliburton, Richard D. White, George P. Chatzimavroudis
Chemical & Biomedical Engineering Faculty Publications
Magnetic-resonance (MR) phase velocity mapping (PVM) shows promise in measuring the mitral regurgitant volume. However, in its conventional nonsegmented form, MR-PVM is slow and impractical for clinical use. The aim of this study was to evaluate the accuracy of rapid, segmented k-spaceMR-PVM in quantifying the mitral regurgitant flow through a control volume (CV) method. Two segmented MR-PVM schemes, one with seven (seg-7) and one with nine (seg-9) lines per segment, were evaluated in acrylic regurgitant mitral valve models under steady and pulsatile flow. A nonsegmented (nonseg) MR-PVM acquisition was also performed for reference. The segmented acquisitions were …
A Steady-State Impedance Model For A Pemfc Cathode, Qingzhi Guo, Ralph E. White
A Steady-State Impedance Model For A Pemfc Cathode, Qingzhi Guo, Ralph E. White
Faculty Publications
A model for the simulation of the steady-state impedance response of a polymer electrolyte membrane fuel cell (PEMFC) cathode is presented. The catalyst layer of the electrode is assumed to consist of many flooded spherical agglomerate particles surrounded by a small volume fraction of gas pores. Stefan-Maxwell equations are used to describe the multicomponent gas-phase transport occurring in both the gas diffusion layer and the catalyst layer of the electrode. Liquid-phase diffusion of O2 is assumed to take place in the flooded agglomerate particles. Newman’s porous electrode theory is applied to determine over-potential distributions. © 2004 The Electrochemical Society. All …