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▶ Start-up/shut-down of a PEFC was simulated by exchanging H2 and air at the anode. ▶ Dye film was used to visualize pO2 at the anode during the H2/air exchange. ▶ Gas exchange rate ...was lowered by protons produced by carbon corrosion at the cathode. ▶ After degradation, oxygen was consumed mainly in the middle of the MEA. ▶ STEM images of the catalyst layer showed holes near the inlet and outlet of the cell.
During start-up/shut-down processes of a polymer electrolyte fuel cell, platinum particles are lost from the catalyst layer at the cathode due to corrosion of the carbon supports. We simulated the start-up/shut-down cycle by exchanging gases at the anode between hydrogen and air. During the gas exchange, the distribution of oxygen partial pressures at the anode was visualized by our real-time/space visualization system, which clearly showed the location of H2- and O2-rich areas along the gas-flow channel from the inlet to the outlet. The gas exchange rate was found to be much slower than that predicted from the simple replacement and to be correlated to the proton transfer derived from carbon corrosion of the cathode catalyst layer. By the visualization results, it was found that the shut-down process gives more serious effect than the start-up process. After the degradation, the oxygen partial pressure at the cathode was visualized during the cell operation. Oxygen was consumed mainly in the middle of the MEA because the MEA was degraded mainly near the inlet and outlet of reactant gases in the cell.
C-SMC (Carbon fiber - Sheet Molding Compound) is formed by mixing carbon fiber with a long fiber and resin. The fiber distribution becomes uneven in the part due to the resin flow during ...manufacturing. Therefore, it is more difficult to grasp the signs at the time of fracture and the growth of cracks than other CFRPs. In this paper, we performed C-SMC tensile strength test and C-SMC structural component test with loading / unloading cycles by acoustic emission and reported the result of evaluation and application of Kaiser effect for C-SMC.
Liver injuries associated with chest compressions are difficult to treat when veno-arterial extracorporeal membrane oxygenation (V-A ECMO) is used. We report two cases of delayed liver injury after ...extracorporeal cardiopulmonary resuscitation cured by laparotomy. One case of liver injury appeared after percutaneous coronary intervention, resulting in abdominal compartment syndrome and emergency laparotomy. The other case of hemorrhagic ascites increased after V-A ECMO was started, resulting in emergency laparotomy. Both patients survived. V-A ECMO required the use of anticoagulants and intra-abdominal hemorrhage caused decreased venous return and increased intra-abdominal hypertension. Our case studies suggest that emergency laparotomy can safely be performed to stop bleeding with liver injury under V-A ECMO.
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▶ Dye film was used to visualize PO2 and water blockages in flow channels of a PEFC. ▶ Water droplets in a gas-flow channel lowered PO2 in the blocked channel. ▶ Air was supplied ...through the GDL to the channel blocked by water droplets. ▶ Under the blocked channel, water formed by power generation was accumulated. ▶ Flooding of catalyst and/or porous layers lowered the power generation.
Visualization inside polymer electrolyte fuel cells (PEFCs) is important for elucidating reaction distributions to improve the performance and durability of the cells. An O2-sensitive porphyrin luminescent dye film was used to visualize oxygen partial pressures and water blockages simultaneously in triple-serpentine gas flow channels in an operating PEFC. Water droplets formed near the exit of a gas-flow channel lowered the oxygen partial pressure noticeably over the channel by blocking air flow near the entrance. Meanwhile, air was continuously supplied from the other channels through the gas diffusion layer, thus allowing power to be generated in the blocked channel. With water blockages, however, the catalyst layer under the channel became flooded by the water produced during the reaction, and the flooded state continued to exist in the catalyst and/or porous layers, even after blowing the water droplet out, so that the power generation was lowered along the channel.
A luminescent PtTFP/PMSP polymer coating was prepared for the oxygen partial pressure visualization inside a PEFC. PMSP formed a smooth and tough coating as a highly oxygen‐permeable matrix with a ...thickness of ca. 2 µm in which the PtTFP was homogeneously dispersed. The coating displayed a strong red luminescence with significantly decreasing intensity upon increasing oxygen partial pressure. The sensitivity for the oxygen partial pressure was high and the analytical curve of the sensor polymer coating was undisturbed by external factors. The PtTFP/PMSP sensor was coated on the surface of a cathode gas diffusion layer on the air flow channel inside PEFC. The oxygen‐pressure distribution in the air flow channel was successfully visualized while operating the PEFC.
A luminescent sensory polymer coating was prepared for the visualization of the oxygen partial pressure in the interior of the cathode separator channels of an operating fuel cell. The coating was stable under irradiation in water, acids, and methanol at high temperatures. The oxygen distribution on the surface of the channel was successfully visualized in real‐time through analysis of luminescence and quenching.
An unconscious 75-year-old female was admitted to our hospital. She went into cardiopulmonary arrest in the emergency room, but was resuscitated successfully. Abdominal computed tomography revealed a ...massive hematoma in the stomach. Gastrointestinal endoscopy was performed, but the source of the bleeding could not be identified. An emergency laparotomy was performed under a diagnosis of a hemorrhagic gastric ulcer. Laparotomy revealed ulcerative lesions in the posterior wall of the upper body of the stomach. A total gastrectomy was performed and the patient was rescued. On postoperative day 35, Roux-Y reconstruction was performed. We report herein on a case of cardiopulmonary arrest due to a hemorrhagic gastric ulcer successfully treated with a two staged operation and discuss the clinical implications based on a review of the literature.
Gas diffusion layer (GDL) is an important component for the performance of polymer electrolyte fuel cells controlling the gas flow and the water transport. In this study, the real-time formation ...process of water droplets on two GDLs with different pore sizes was imaged using a CCD camera during the cell operation. A porphyrin luminescent dye was coated on the GDLs to clarify the shape of the water droplets. On the GDL with a smaller pore size, the droplets were distributed uniformly on the GDL in the flow channel at the cathode. On the GDL with a larger pore size, the water droplets were larger and formed mainly near the ribs of the flow channel, and the droplets were observed to move slowly towards the gas outlet. The difference in the formation of water droplets were explained by the difference in the partial air flow inside the GDLs along the gas channel.
Liver injuries associated with chest compressions are difficult to treat when veno-arterial extracorporeal membrane oxygenation (V-A ECMO) is used. We report two cases of delayed liver injury after ...extracorporeal cardiopulmonary resuscitation cured by laparotomy. One case of liver injury appeared after percutaneous coronary intervention, resulting in abdominal compartment syndrome and emergency laparotomy. The other case of hemorrhagic ascites increased after V-A ECMO was started, resulting in emergency laparotomy. Both patients survived. V-A ECMO required the use of anticoagulants and intra-abdominal hemorrhage caused decreased venous return and increased intra-abdominal hypertension. Our case studies suggest that emergency laparotomy can safely be performed to stop bleeding with liver injury under V-A ECMO.
Visualization of the oxygen partial pressures was carried out at the surface of a gas diffusion layer (GDL) for the first time together with the upper part of the gas-flow channel of the cathode of a ...running polymer electrolyte fuel cell (PEFC) using two different oxygen-sensitive luminescent dye films. The visualized distributions of the oxygen partial pressures at the GDL and the upper gas-flow channel during the PEFC operation were very different in a conventional test cell. The change in the distribution of the oxygen partial pressures was observed by changing the oxygen utilization, which should be connected with the reactive locations in the membrane-electrode assembly (MEA). A numerical calculation was carried out to understand the distributions of water and current density inside the MEA. The water distribution inside the MEA was confirmed to strongly affect the distributions of the current density and the oxygen/partial pressure.
This paper presents a FPGA-based analog-digital hybrid real-time simulator (HRTS)with a new state space representation method. In the proposed method, electro-magnetic transient models with switches ...are represented by parallel ordinary differential equation (ODE)based on a block-diagonal decomposition of matrix. This paper also proposes a new update rule of state space form in order to accurately calculate with limited resources. The proposed method can be implemented with low costs of computation, and enables accurate computation with a less size fixed point of Field-Programmable Gate Array (FPGA). We implemented a doubly fed induction generator (DFIG)based wind turbine model on the FPGA using the proposed method and connected it to the analog simulator via a current source. By comparing with MATLAB/Simulink references, the effectiveness of the proposed method is illustrated.
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