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The aim of this study is to investigate the effects of the separator thickness on not only the heat and mass transfer characteristics, but also the power generation characteristics of a polymer electrolyte membrane fuel cell (PEMFC) with a thin polymer electrolyte membrane (PEM) and thin gas diffusion layer (GDL) operated at higher temperatures of 363 and 373 K. The in-plane temperature distributions on the back of the separator at the anode and cathode, which are the opposite sides to the GDL, are measured using a thermograph at various initial cell temperatures (Tinit), relative humidity (RH) levels, and supply gas flow rates. The total voltage corresponding to the load current is measured in order to evaluate the performance of the PEMFC. As a result, it is revealed that the effect of the RH on the power generation characteristics is more significant when the separator thickness decreases. It is revealed that the power generation performance obtained at high current densities decreases with the increase in Tinit with thinner separator thicknesses. According to the investigation of the in-plane temperature distribution, it is clarified that the temperature decreases at corner positions in the separator with the separator thickness of 2.0 mm, while the temperature gradually increases along with the gas flow with separator thicknesses of 1.5 mm and 1.0 mm.

The purpose of this study is to understand the impact of the thickness of Nafion membrane, which is a typical polymer electrolyte membrane (PEM) in Polymer Electrolyte Membrane Fuel Cells (PEMFCs), and relative humidity of supply gas on the distributions of H2, O2, H2O concentration and current density on the interface between a Nafion membrane and anode catalyst layer or the interface between a Nafion membrane and cathode catalyst layer. The effect of the initial temperature of the cell (Tini) is also investigated by the numerical simulation using the 3D model by COMSOL Multiphysics. As a result, the current density decreases along with the gas flow through the gas channel irrespective of the Nafion membrane thickness and Tini, which can be explained by the concentration distribution of H2 and O2 consumed by electrochemical reaction. The molar concentration of H2O decreases when the thickness of Nafion membrane increases, irrespective of Tini and the relative humidity of the supply gas. The current density increases with the increase in relative humidity of the supply gas, irrespective of the Nafion membrane thickness and Tini. This study recommends that a thinner Nafion membrane with well-humidified supply gas would promote high power generation at the target temperature of 363 K and 373 K.

The aim of this study is to clarify the impact of the thickness of a gas diffusion layer (GDL) and a micro porous layer (MPL) on the distributions of gas, H2O, and current density in a polymer electrolyte fuel cell (PEFC) which is operated at 363 K and 373 K and with various thicknesses of polymer electrolyte membrane (PEM) as well as a relative humidity (RH) of supply gas. These investigations are carried out by numerical simulation using the 3D model with COMSOL Multiphysics. In the case of Nafion 115, which is the thicker PEM, the change in the molar concentration of H2O from the inlet to the outlet with MPL is larger than that without MPL irrespective of the thickness of GDL, Tini and RH condition. In the case of Nafion NRE-212, which is the thinner PEM, the change in the molar concentration of H2O from the inlet to the outlet is larger with MPL than that without MPL in the case of TGP-H-060 (the thicker commercial GDL), while that is smaller with MPL than that without MPL in the case of TGP-H-030 (the thinner commercial GDL). These results exhibit the same tendency as the results of the numerical simulation on the current density.

The present study aims to analyze the performance characteristics of the biogas dry reforming process conducted in a membrane reactor using Ni/Cr catalysts and to compare these characteristics with those obtained using pure Ni catalysts. The effect of the pre-set reaction temperature, the molar ratio of CH4:CO2 and the pressure difference between the reaction chamber and the sweep chamber on the characteristics of biogas dry reforming is analyzed. In the present work, the molar ratio of the supplied CH4:CO2 is varied to 1.5:1, 1:1 and 1:1.5. In this case, CH4:CO2 = 1.5:1 simulates a biogas. The pressure difference between the reaction chamber and the sweep chamber is varied to 0 MPa, 0.010 MPa and 0.020 MPa. The reaction temperature is changed to 400 °C, 500 °C and 600 °C. It is revealed that the highest concentration of H2 is achieved using a Ni/Cr catalyst when the molar ratio of CH4:CO2 is 1.5:1 at the differential pressure of 0.010 MPa and the reaction temperature of 600 °C. Under this condition, the H2 yield, H2 selectivity and thermal efficiency are 12.8%, 17.5% and 174%, respectively. The concentration of the H2 produced using a Ni/Cr catalyst is larger than that produced using a Ni catalyst regardless of the pre-set reaction temperature, the molar ratio of CH4:CO2 and the differential pressure.

The present study pays attention to biogas dry reforming for the purpose of producing H2. It is known that biogas contains approximately 40 vol% CO2, causing a decrease in the efficiency of power generation due to its lower heating value compared to natural gas, i.e., CH4. We suggest a hybrid system composed of a biogas dry reforming membrane reactor and a high-temperature fuel cell, i.e., a solid oxide fuel cell (SOFC). Since biogas dry reforming is an endothermic reaction, we adopt a membrane reactor, controlled by providing a non-equilibrium state via H2 separation from the reaction site. The purpose of the present study is to understand the effect of the thickness of the Pd/Cu membrane on the performance of the biogas dry reforming membrane reactor with a Pd/Cu membrane as well as a Ni/Cr catalyst. The impact of the reaction temperature, the molar ratio of CH4:CO2 and the differential pressure between the reaction chamber and the sweep chamber on the performance of the biogas dry reforming membrane reactor with the Pd/Cu membrane as well as the Ni/Cr catalyst was investigated by changing the thickness of the Pd/Cu membrane. It was revealed that we can obtain the highest concentration of H2, of 122,711 ppmV, for CH4:CO2 = 1:1 at a reaction temperature of 600 °C and a differential pressure of 0 MPa and using a Pd/Cu membrane with a thickness of 40 μm. Under these conditions, it can be concluded that the differential pressure of 0 MPa provides benefits for practical applications, especially since no power for H2 separation is necessary. Therefore, the thermal efficiency is improved, and additional equipment, e.g., a pump, is not necessary for practical applications.

In hydrogen energy systems, the polymer electrolyte fuel cell (PEFC) is an important component. The purpose of this study is to clarify the effect of separator thickness (s.t.) in PEFC on the distributions of mass such as H2, O2, H2O and current density when PEFC is operated at 363 K and 373 K. The relative humidity (RH) of supply gases also impacts the operation. The numerical simulation (using a 3D model) with COMSOL Multiphysics has been conducted to analyze the characteristics of PEFC. It has been observed that the molar concentration of H2 using s.t. of 2.0 mm is smaller compared with the thinner s.t. cases at the initial operation temperature of a cell (Tini) = 363 K and 373 K. The molar concentration of O2 using s.t. of 2.0 mm is smaller compared with the thinner s.t. cases at Tini = 373 K, as well as the case for the RH of supply gases at the anode of 40%RH and cathode of 40%RH (A40%RH/C40%RH) irrespective of Tini. Additionally, it has been clarified that the molar concentration of H2O maintains a low value along with the gas channel at Tini = 373 K using s.t. of 1.5 mm and 1.0 mm. Moreover, it has been clarified that the current density using s.t. of 2.0 mm is the highest among the different s.t. irrespective of Tini, which is the most remarkable in the case of A40%RH&C40%RH.

Aims/Introduction Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long‐term treatments are available. Methods This was an investigator‐initiated multicenter prospective intervention study in which ipragliflozin (50 mg) was administered once daily, and glycemic control, estimated glomerular filtration rate (eGFR) and adverse events were evaluated until 104 weeks after starting research. Results There were 407 patients analyzed. In the eGFR ≥90 group and eGFR ≥60 to <90 group, eGFR had significantly decreased compared with baseline at all time points from 4 to 104 weeks. There were significant increases in the eGFR ≥45 to <60 groups compared with baseline at 36 weeks (2.3 ± 1.0) and 52 weeks (2.6 ± 1.2). Comparison between the eGFR <60, urine albumin‐to‐creatinine ratio >300 group and the eGFR <60, urine albumin‐to‐creatinine ratio <300 group showed a greater reduction in eGFR in the former (−5.4 ± 2.4 vs 3.3 ± 1.1) at 12 weeks and was maintained to 104 weeks. In any group, eGFR did not significantly decrease until 104 weeks compared with 4 weeks. The urine albumin‐to‐creatinine ratio after 52 weeks and after 104 weeks was significantly decreased compared with baseline in the eGFR ≥90 group. Conclusions Ipragliflozin lowers eGFR and corrects hyperfiltration in patients with high eGFR (eGFR ≥60). In patients with low eGFR (eGFR ≥30 to <60), ipragliflozin has the possibility of increasing eGFR and exerting a renoprotective effect. In the estimated glomerular filtration rate (eGFR) ≥90 group and eGFR ≥60 to <90 group, eGFR had significantly decreased compared with baseline at all time points from 4 to 104 weeks. There were significant increases in the eGFR ≥45 to <60 groups compared with baseline at 36 weeks (2.3 ± 1.0) and 52 weeks (2.6 ± 1.2). In each group, there was no significant change compared with 12 weeks at all time points between 24 and 104 weeks.