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The Microbiome of the Built Environment (MoBE) is profoundly implicated in various sectors, including food science. The balance between beneficial and pathogenic microbes in these facilities directly influences product quality and public health. Maintaining a careful check on MoBE and external microbes is vital to the food industry to ensure quality control. There is also a risk of contamination in the meat processing facility as well. However, over-sanitization can increase drug-resistant microbes, highlighting the importance of balanced microbial management. Additionally, facility design, influenced by understanding MoBE, can optimize the growth of beneficial microbes and inhibit pathogenic microbes. Microbial mapping, an emerging practice, offers insights into microbial hotspots within facilities, resulting in targeted interventions. As the food industry evolves, the intricate understanding and management of MoBE will be pivotal to ensuring optimal food quality, safety, and innovation.Graphical AbstractDuring manufacturing, foods interact with The Microbiome of the Built Environment in the food-processing facility in multiple aspects.

The spatial distribution of current and temperature plays important role in the electrochemical performance of Solid Oxide Electrolysis Cells (SOECs). Many numerical predictions of current and temperature distribution have been reported, whereas experimental investigations were rare. In this research, we are applying an electrode-segmentation method to investigate the spatial current and temperature variation in a cathode-supported microtubular SOEC. The electrode-segmentation method shows a remarkable current variation among the segments. The current densities of the midstream and downstream segments are smaller than the upstream segment with an increased cell voltage, implying that the cell suffers from water starvation. Besides, the temperature at each segment increases with the voltage increase. The largest current in the upstream segment is observed, which agrees with the largest temperature rise there. The largest temperature gradient happens between the upstream and midstream segments.

Orally administered drugs are absorbed and metabolized in the intestine. To accurately predict pharmacokinetics in the intestine, it is essential to understand the intestinal expression profiles of the genes related to drug absorption, distribution, metabolism, and excretion (ADME). However, in many previous studies, gene expression analysis in the intestine has been carried out using specimens from patients with cancer. In this study, to obtain more accurate gene expression profiles, biopsy samples were collected under endoscopic observation from the noninflammatory regions of 14 patients with inflammatory bowel disease, and RNA-seq analysis was performed. Gene expression analysis of drug-metabolizing enzymes (cytochromes P450), non–cytochrome P450 enzymes, nuclear receptors, drug-conjugating enzymes (UDP-glucuronosyltransferases and sulfotransferases), and apical and basolateral drug transporters was performed in biopsy samples from the duodenum, ileum, colon, and rectum. The proportions of the cytochromes P450 expressed in the ileum were 25% (CYP3A4), 19% (CYP2C18), and 14% (CYP3A5). CYP3A4and CYP2C19were highly expressed in the duodenum and ileum, but not in the colon and rectum. In the ileum, apical transporters such as P-gp, peptide transporter 1, breast cancer resistance protein, MRP2, and ASBTwere strongly expressed, and the expression levels of P-gpand ASBTin the ileum were higher than those in other regions. In the ileum, basolateral transporters such as OSTα, OSTβ, and MRP3were strongly expressed. We succeeded in obtaining gene expression profiles of ADME-related genes in human intestinal epithelial cells in vivo. We expect that this information would be useful for accurate prediction of the pharmacokinetics of oral drugs.SIGNIFICANCE STATEMENTTo obtain gene expression profiles of ADME-related genes in human intestinal epithelial cells in vivo, biopsy samples were collected under endoscopic observation from the noninflammatory regions of 14 patients with inflammatory bowel disease, and RNA-seq analysis was performed. Gene expression profiles of drug-metabolizing enzymes (cytochromes P450), non–cytochrome P450 enzymes, nuclear receptors, drug-conjugating enzymes (UDP-glucuronosyltransferases and sulfotransferases), and apical and basolateral drug transporters in biopsy samples from the duodenum, ileum, colon, and rectum were obtained in this study.

Reducing platinum group metal (PGM) loading and high current density operation are both essential for minimizing the capital expenditure (CAPEX) of polymer electrolyte membrane (PEM) electrolyzers. Catalyst-integrated porous transport electrodes (PTEs) in which iridium acts as both a catalyst and a conductive coating on porous transport layer (PTL) surfaces, enable the preparation of Pt-coating-free PTLs, but can also result in relatively high activation and ohmic overvoltages. Here, a novel hybrid anode design combining an intermediate catalyst layer and a catalyst-integrated PTE is developed. This hybrid anode demonstrates that Ir on PTL can contribute to the oxygen evolution reaction (OER) and exhibits comparable electrolysis performance to a conventional anode consisting of Pt-coated PTL with the same Ir loadings despite Pt-coating-free on the PTL of the hybrid anode. This novel anode eliminates the need for a Pt coating whilst also enabling ultra-high current density operations up to 20 A cm−2with a total PGM loading of only around 0.6 mg cm−2on the anode side. This paper proposes a next-generation anode structure with new functions of PTLs for ultra-high current density operation with low PGM loading to significantly reduce green hydrogen costs.

In recent years, the establishment of Power to Gas technology is in progress. Promising methods include steam electrolysis and co-electrolysis using the Solid Oxide Electrolysis Cell (SOEC). We have developed a honeycomb electrolytic cell with a larger reactive area per unit volume than the conventional flat and tubular types. Thereby volumetric density of fuel production rate can be greatly improved, leading to a development of compact and high performance steam electrolysis systems. In this study, we address hydrogen production by steam electrolysis with an SOEC having a porous honeycomb support consisting of Ni-YSZ cathode. Current-voltage curves were measured with sampling the cathode outlet gas for gas chromatography. As the results, we confirmed that hydrogen concentration in the outlet increased as the current increased. The experimental results are useful to validate numerical models to design practical honeycomb cells.

Some metal oxides are stable under strongly acidic conditions of Polymer Electrolyte Membrane Water Electrolysis (PEMWE) anodes. Such oxides may be useful as catalyst support materials to reduce noble metal catalyst loading (such as iridium) and to improve electrode durability. In this study, the titanium-based porous sheet acting as the Gas Diffusion Layer (GDL), on which its surface is naturally oxidized, is used as the support material. GDL-integrated electrodes with Ir-based electrocatalysts are developed. Two types of GDL-integrated electrodes were prepared with Ir-based electrocatalysts deposited by the Arc Plasma Deposition (APD) or the evaporation-to-dryness process. A higher Oxygen Evolution Reaction (OER) activity was obtained for electrodes prepared by the APD compared to those prepared by the evaporation-to-dryness process. Electrochemical activity and durability of the Ir-based electrocatalysts on the porous Ti sheet in MEAs are characterized and discussed.

The numerical analysis conducted in this study proposes a guideline to maximize the high-temperature effect, which is expected to reduce the electrolysis voltage of the polymer electrolyte membrane water electrolyzer. High-temperature operation is intuitively thought to reduce activation overvoltages. However, a further consideration predicts that high temperature, especially a temperature higher than the saturated temperature regulated in the operation pressure, decreases the liquid saturation and causes shortage of water, leading to a large increase in overvoltages. This high temperature problem is analyzed using the developed theoretical model, which considers gas/liquid behavior. The analysis suggests that, if the gas saturation in the anode catalyst layer is kept at or below 0.3 by increasing the pressure, liquid water in the catalyst layer is sufficient to OER catalytic ability regulated by exchange current density, demonstrating that the high-temperature effect works. According to this guideline, increasing the temperature with pressurization can monotonically reduce the anode activation overvoltage. For instance, raising the temperature from 100 to 120degC and raising the pressure from 0.13 to 0.22 MPa can prevent the gas saturation from increasing beyond 0.3 and allows the lower electrolysis voltage to vary from 1.57 to 1.51 V.

Carbon black is difficult to be used as the catalyst support material for polymer electrolyte membrane water electrolysis (PEMWE) due to carbon corrosion at a high potential. In order to prepare iridium-based nano-size electrocatalysts similar to PEFC, SnO2 and TiO2 are considered as possible catalyst support materials with high potential stability. In this study, we prepare (i) iridium-decorated SnO2 supported on Vapor-Grown Cabon Fiber (IrO2/Sn(Nb)O2/VGCF) and (ii) carbon-free Ir/TiOx/Ti sheet where Ti sheet with naturally oxide surface is used as the catalyst support and the gas diffusion layer (GDL). Ir nanoparticles on each metal oxide support could be prepared, confirmed by electron microscopy. The Ir/TiOx/Ti electrode exhibited higher IV characteristics with a lower Ir loading than the IrO2/Sn(Nb)O2/VGCF electrode.

This study challenges to decrease water electrolysis voltage by thermodynamic coupling between boiling and water electrolysis. Boiling, once a system to cause boiling is given, spontaneously advances and causes entropy generation. When boiling is superimposed on an electrode where electrochemical reaction of water electrolysis progress, the entropy generation by the boiling possibly accelerates the reaction of water electrolysis, leading to reduction of electrolysis voltage. To confirm this new concept, electrolysis voltage for a unit cell of PEMWE is measured in the region from 80degC to 120degC under a condition that cell pressure and electrolysis current are kept constant. The measurement results showed that the electrolysis voltage abruptly decrease as cell temperature crosses boiling point and then turn to increase at a few degree higher than the point. These features in the measurement were reproduced in the theoretical analysis based on a mathematical model considering the thermodynamic coupling.

In the planar solid oxide fuel cell (SOFC), the fuel/oxidant distributions cause current and temperature distributions over the electrodes under the separator (interconnector) ribs and flow channels. Optimized designs of the separator to improve the output power and chemical/thermo-mechanical durabilities of practical stacks require numerical models validated by insitu current distributions measured. We have therefore clarified the difference of in-situ measurements inplane spatial current variations between an anode-supported planar SOFC and electrolyte-supported by segmented cathodes opposing the anode rib and flow channels. We focus on the effect of the rib width on the spatial current distribution. We model the current and hydrogen partial pressure distributions by finite element modeling so that the model agrees with the insitu measurements by the segmented cathodes with determining the exchange current densities, electrode porosities, electrolyte ion conductivities, and electrode ion/electron conductivities.

Secure sealing is vital for planar type SOFCs to avoid the performance degradation and achieve long-term stable operation. Here we focus on the sheet type glass sealing which is produced by tape-casting method. High wettability of the glass is essential to avoid the stress concentration because low wettability increases the contact angle of the glass and makes the notch at the edge of glass sealing interface. We have evaluated the effect of temperature rising rate on the wettability of the sealing glass and the edge shape of it using the visualization test system. High temperature rising rate led to small contact angle of the sealing glass in some cases and can mitigate the stress concentration.

In the planar solid oxide fuel cell (SOFC), the fuel/oxidant distributions cause current and temperature distributions over the electrodes under the separator ribs and flow channels. Optimized designs of the separator to improve the output power and chemical/thermo-mechanical durabilities of practical stacks require numerical models validated by insitu current distributions measured. We have therefore addressed in-situ measurements of inplane spatial current variations of an electrolyte-supported planar SOFC by segmented cathodes opposing the anode rib and flow channels. We focus on the effect of the rib width on the spatial current distribution. We model the current and hydrogen partial pressure distributions by finite element modeling so that the model agrees with the insitu measurements by the segmented cathodes with determining the exchange current densities, electrode porosities, electrolyte ion conductivities, and electrode ion/electron conductivities.

P-glycoprotein (P-gp) expression in lymphocytes is variable and 2-fold higher in rheumatoid arthritis (RA) patients with treatment resistance than in healthy subjects. To date the information on P-gp-mediated drug interaction in lymphocyte is limited. We analyzed the importance on P-gp in lymphocytes using peripheral blood mononuclear cells (PBMCs) together with K562, K562/Adr, and K562/Vin cells, which have various P-gp levels, as cell models, and dexamethasone, nintedanib and apafant as weak to good P-gp substrates. P-gp levels in K562, K562/Adr, and K562/Vin cells were 0.3-, 20-, and 106-fold of healthy PBMCs, respectively. While cell accumulation of apafant and nintedanib decreased in all cells with increasing P-gp levels, dexamethasone accumulation in K562/Adr was comparable to that in healthy PBMCs and K562 cells. Cell accumulations of substrates in cells with low P-gp expression were not significantly changed by the P-gp inhibitors at therapeutic concentrations. However, accumulation increased to 1.4-fold at highest in K562/Adr cells with higher P-gp expression than in PBMCs of the RA patients. These results suggest P-gp controls the cellular concentration of P-gp substrates in PBMCs or K562 cells but cellular concentration of a weak P-gp substrate would not be apparently affected even in cells with a sufficient P-gp expression.

The electrode segmentation method has been applied to experimentally assess the current and temperature distributions in a cathode-supported microtubular solid oxide electrolysis cell (mt-SOEC). A detailed three-dimensional SOEC model considering the mass/momentum/charge/energy transfer is also developed to explain the in-situ working mechanism with spatial current and temperature variations considering the electrochemical performance and degradation. Both the experimental and numerical results reveal that the electrode-segmentation method exhibits notable nonuniform current and temperature distributions among the segments (up-, mid-, and downstream). Reactant starvation in the mid- and downstream regions leads to spatial current and temperature variations, with the largest temperature gradient observed and predicted between the up- and midstream regions. Further analysis of the temperature variations indicates that endothermic electrochemical Peltier heat in the air (oxygen) electrode (anode) is the primary cause of temperature decrease from 1.0 V to 1.3 V, while heat production with the overpotentials in the fuel (hydrogen) electrode (cathode) dominates temperature increase above 1.3 V.

To investigate the impact of annealing conditions on electrolysis performance, annealed IrO2 powders are examined as anode catalysts in a high temperature polymer electrolyte membrane water electrolyzer (PEMWE). The IrO2 powders were annealed for from 1 to 8hours under 350oC and 490oC. The effect of annealing time and temperature on the IrO2 phase, specific surface area of IrO2 and high frequency resistance (HFR) is investigated through analyzing the current-voltage (I-V) characteristics. The experiment result shows that annealing impacts on electrolysis performance majorly through changing IrO2 phase. Both lengthening annealing time and elevating annealing temperature change IrO2 phase from amorphous phase to crystal phase. The optimum annealing conditions is annealing IrO2 powder at 350oC for 1hour.

Overpotentials included in electrochemical hydrogen pump is separated with using a reference electrode. Separation result shows that non-ohmic overpotential in cathode is larger than that in anode. This result is also confirmed by electrochemical impedance spectra measurement, which shows impedance spectra of cathode is larger than that of anode. Volmer-Heyrovsky-Tafel mechanism is used to explain the separation result. Simulation result with using this mechanism suggests that reactions in anode and cathode are dominated by different mechanisms, and reaction rate of cathode is 2 orders of magnitude slower than that of anode.

Hydrogen gas crossover, which reduces current efficiency, is critical issue in high pressure PEMWE (Polymer Electrolyte Membrane Water Electrolysis). This study proposes controlled wettability current collector, which enhances the detachment of hydrogen gas bubble from the current collector and decreases the crossover. A high pressure operation of a PEMWE cell with visualization clarified that the wettability impacts on the bubble dynamics and changes the current efficiency. Among the current collectors prepared, hydrophilic one indicated higher current efficiency and suggested smaller crossover.

Novel iridium-based electrocatalysts supported on SnO2/Vapor-Grown Carbon Fiber (VGCF) have been developed and characterized by FESEM, STEM, and XPS. The membrane electrode assembly (MEA) made with the IrO2/Sn0.98Nb0.02O2/VGCF electrocatalyst exhibited a decrease in overvoltage especially under the low current density compared to the MEA made with conventional IrO2/Ti electrocatalyst. Iridium-based SnO2/VGCF can be a good candidate for anode catalysts of water electrolysis cells.

In multifiber all-optical networks, optical amplifiers are used for amplifying multiple optical signals with different wavelengths in fibers. An optical amplifier operates when any of light-paths passes through it. Therefore, it should simultaneously amplify as many lightpaths as possible for efficiently utilizing its power. This paper proposes a dynamic lightpath establishment scheme considering the use efficiency of the optical amplifiers and the depletion of the wavelength resources in multifiber all-optical networks. The proposed scheme provides a routing and wavelength assignment strategy that reduces both the power consumption of the optical amplifiers and the blocking probability of the lightpath establishment. Through simulation experiments, we demonstrate the effectiveness of the proposed scheme.

The effect of cathode current collectors on polymer electrolyte membrane water electrolysis (PEMWE) was evaluated with I-V and I-high frequency resistance (HFR) characteristics. Results reveal that cathode current collectors can impact water electrolysis performance by controlling the amount of water accumulation there, which is proved with overpotential analysis and systematic operation such as feeding additional nitrogen gas to cathode. The hydrophilic cathode current collectors invited better performance than hydrophobic ones, because the hydrophilic ones gives less water accumulation there and enough water content in catalyst coated membrane (CCM). The thickness of cathode current collector did not impact the performance.

An advantage of polymer electrolyte membrane water electrolysis (PEMWE) over other water electrolysis technologies is its ability to operate at high current densities. However, resistive heating during . In this study, the internal cell temperature distribution at high current densities up to 12 A cm-2is evaluated through numerical simulation. The correlation between the temperature gradient in the cell and the flow rate of water supplied is examined. An increase in water supply is effective in minimizing high temperature gradients at higher current densities.

The characteristics of hydrogen gas permeation through a polymer electrolyte membrane (PEM) are important in determining the performance of electrochemical systems such as fuel cells and electrolyzers. However, the only available data related to these characteristics are those for the hydrogen permeability, which were obtained from measurements under a given pressure difference through the PEM. Although we can derive the solubility and self-diffusivity from the permeability, the derivation requires a mathematical procedure, such as providing a gas transport model and fitting experimental data with theoretical data from the model. In this study, we developed a measurement system that uses nuclear magnetic resonance and can quantify both the solubility and self-diffusivity in a rather straightforward manner. The system allows us to measure these two properties when hydrogen gas is dissolved in a dry Nafion membrane under a hydrogen gas pressure of up to 1 MPa at room temperature. The solubility increases linearly with increasing pressure, and the solubility coefficient is (1.3 +- 0.13) x 10[?]5 mol/(cm3MPa). The self-diffusivity shows a constant value of (2 +- 0.4) x 10[?]6 cm2/s regardless of the pressure.

A new cross-sectional visualization cell in which a transparent material is not embedded in the separator was developed to observe water droplet behavior in a flow channel and to analyze the impact of the channel and gas diffusion layer (GDL) surface on the behavior. A specific GDL and separator pair was chosen so that the surface of the GDL was more hydrophobic than that of the separator, where the contact angle difference between them was approximately 27deg. With this GDL and separator pair, a droplet formed in the channel does not touch the GDL surface. This specific pair also makes the droplet smaller and causes less of a pressure drop through the channel, leading to superior drainage from the channel. A theoretical analysis based on the force balance surrounding a droplet explains this superior drainage. The reason is that the combination of the hydrophobic GDL and hydrophilic separator reduces the adhesion force on the droplet, promoting water drainage.

In order to understand the water transport phenomenon in a membrane electrode assembly (MEA), the water transfer resistance through a platinum catalyst layers (CL) is required. In this study, the overall water transfer resistance through the CL is taken as the sum of the resistance to charge/discharge water from the surface of ionomer in the CL and the resistance for water to pass through the ionomer in the CL. The value of this quantity for a CL that is 4 um thick and is coated on a 178 um thick Nafion 117, was estimated. The MEA was dried/wetted by supplying gas with controlled humidity to the surface of the MEA. The water concentration contained in the PEM was measured by nuclear magnetic resonance (NMR) using a small detection coil. The rates of drying/wetting of the MEA were calculated from time-dependent changes of the water concentration measured in the PEM. The overall water transfer resistance through a CL was estimated by comparing experiment and analytical results based on the analytical model. As a result, the overall water transfer resistances through the 4 um thick CL during drying and wetting were 0-3 x 104 and 10 +- 6 x 104 s/m, respectively.

Polymer electrolyte membrane (PEM) used for fuel cells and water electrolyzers is permeable to hydrogen gas, and the permeation causes to decreases performance as electrochemical system. So, it is necessary to figure out the mechanism of hydrogen gas permeation and to develop PEM that has lower gas permeability. In this study, we developed a new measurement system for hydrogen-gas solubility and diffusivity in PEM based on NMR technique, which enables us to estimate the solubility and diffusivity without assuming theoretical dissolution model. We apply the system to the dissolved hydrogen-gas in dry Nafion(r)117. The solubility obtained is proportional to ambient pressure and 2.9x10-5 mol/cm3@0.7MPa. The diffusivity is 3x10-10 m2/s. These values are discussed with comparing the values measured in conventional method.

It is desired to develop computational procedures to simulate an internal current density, anode/cathode gas concentrations and a temperature distribution in solid oxide fuel cell (SOFC) systems. In this study, the influences of various operational conditions on the exchange current density which is the essential parameter to simulate SOFC performance were discussed. The anodic exchange current density depended strongly on the humidity of H2, and it exhibited the highest value at around 40% H2O. The cathodic exchange current density was strongly affected by the operational temperature. Parameters necessary to describe dependences of exchange current density on the operational conditions were determined by fitting measured exchange current density with the empirical equations.

Sulfur poisoning effect on the electrochemical performance and long-term durability of SOFC cathodes has been investigated for (La0.8Sr0.2)0.98MnO3 (LSM) and La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) up to 1000 hours. Gradual degradation of performance occurred, associated with the formation of strontium sulfate, which depended on SO2 concentration.

Liquid water growth pattern in the gas flow channel in PEFC was visualized by using an ex-situ optical cross-sectional observation system developed. We investigated the impact of surface hydrophobicity of the GDL and channel on the liquid water growth pattern. The liquid water, which was emerged at 5 mm back from the gas outlet, was observed with spatial resolution of 20 um by optimizing the optical system including CCD camera. Pressure drop through the channel was measured to evaluate the impact of water droplet on it. As a result, it is obtained that adhesion force formed in combination of hydrophobic GDL and hydrophilic channel sucked the water from GDL to channel corner, and suppressed the water contact with the GDL surface, and accelerated the water drainage, leading to prevent the water droplet growing in the channel.

Durability of electrocatalysts under severe operational conditions of polymer electrolyte fuel cells (PEFCs) is one of the most important technological issues to be improved. Alternative electrocatalyst support materials are desired, the use of which may solve problems such as oxidation-induced carbon support corrosion. One interesting solution is to use conductive oxide-based catalyst support. We focus our attention to SnO2, known as an oxide semiconductor with a high electronic conductivity. Nano-carbon support materials are also studied as an another option of electrocatalyst support design. Technical merits and remaining issues in alternative electrocatalyst support materials selection are discussed.

This paper proposes new testing methods for evaluating the effects of freeze-thaw action on the deformation-strength characteristics and the water retention-permeability characteristics of granular materials under unsaturated conditions. A triaxial apparatus and a permeability apparatus for unsaturated soils, with cooling systems to control the temperature of soil specimens and use the pressure membrane method instead of the pressure plate method, were newly developed in order to examine the hydro-mechanical behavior of unsaturated soils subjected to the freeze-thaw sequence, as experienced by in-situ soils in cold regions. Results indicate that the proposed testing methods with these newly developed test apparatuses are highly useful in the evaluation of the effect of freeze-thaw action on the hydro-mechanical behavior of unsaturated granular materials and in the reduction of total testing time.

The temperature distribution across a proton exchange membrane fuel cell was measured by inserting micro-thermocouples between layers such as a gas diffusion layer and membrane electrode assembly. Under steady-state operation, the cathode catalyst layer had the maximum temperature. The activation overpotential at the cathode catalyst layer served as the main heat source, resulting in the maximum temperature at the cathode catalyst layer. The temperature at the cathode catalyst layer just after the load current was interrupted had the minimum temperature. This is thought to be caused by water evaporation from the cathode catalyst layer, where liquid water accumulates during operation.

OGG1 protein has an ability to suppress mutagenesis induced by 8-hydroxyguanine (8OHG), an oxidatively damaged promutagenic base. Here, the mutation suppressive ability was compared between two common polymorphic OGG1 proteins, OGG1-Ser326 and OGG1-Cys326, using a supF forward mutation assay employing an 8OHG-containing plasmid. Polymorphic OGG1 proteins were exogenously expressed by adenoviral transduction in H1299 human lung cancer cells, in which endogenous OGG1 protein was undetectable by western blot analysis. Mutations by 8OHG were more efficiently suppressed in OGG1-Ser326 transduced cells than OGG1-Cys326 transduced cells. The results indicated that OGG1-Cys326 has a lower ability to prevent mutagenesis by 8OHG than OGG1-Ser326 in vivo in human cells; supporting the results of recent association studies that OGG1-Cys326 is a risk allele for several types of human cancers.

OH radicals play a very important role in non-thermal plasma chemical reactions for decomposition of gaseous pollutants or synthesis of methanol from methane, etc. In this paper, the CO oxidation monitoring method, which has been used in atmospheric chemistry, was examined to measure the concentration of OH radicals produced by a pulsed discharge plasma. The concentration of OH radicals in the discharge plasma of H₂O/Ar mixture gas was estimated by measuring the amount of CO₂ produced through oxidation of CO by OH radicals. The experimental results and the calculated results showed that it is possible to measure OH radicals using this simple method. In this experimental work, the maximum concentration of OH radicals produced by the pulsed discharge plasma of H₂O/Ar was measured to be 9.4×10¹⁴ molecules cm⁻³ pulse⁻¹. Within the temperature range investigated in this study (50–150°C), the formation of OH radicals increased with increase in the specific input energy (discharge energy dissipated in unit volume of the gas; SIE) value and the content of H₂O; in contrast, it decreased with increase in the gas temperature.

The characteristic size of electronic de vices is rapidly approaching the electron and phonon mean free paths in semiconductor materials. In such de vices, the nonequilibrium condition near the interface affects the thermal and charge transport considerably. A microscopic approach is thus required to model the transport in the de vice. In this study, the authors expand on a pre vious study of thermal and charge transport near a point contact interface by solving the Boltzmann equation numerically. The electron distribution function, electric field, and thermoelectric voltage are reported, and the nonequilibrium properties and transport near the point contact are discussed quantitati vely.

Novel catalyst-integrated gas diffusion electrodes (GDEs) for polymer electrolyte membrane water electrolysis (PEMWE) cells are presented, in which porous titanium microfiber sheets are etched in NaOH to generate a nanostructured TiO2surface, followed by arc plasma deposition (APD) of iridium nanoparticles. The porous titanium sheet acts as a gas diffusion layer (GDL); the nanostructured TiO2surface acts as a catalyst support with large surface area; and the iridium nanoparticles act as the electrocatalyst. The performance of these unique GDEs in PEMWE cells was optimized by etching in different NaOH concentrations to vary the nanostructure of the TiO2; and by varying the Ir loading via the number of APD pulses. The current-voltage characteristics and the durability of the optimized GDEs were comparable to those reported in the literature using conventional Ir-based electrocatalysts, and electrolysis was achieved with current density up to 5 A cm?2. The main advantages of this catalyst-integrated GDE include the very low iridium loading (i.e. around 0.1 mg cm?2, or just one-tenth of the loading typically used in conventional PEMWEs); high electrolysis current density; the fabrication of stacks with fewer components; and the fabrications of thinner stacks. This could ultimately lead to smaller and lower cost PEMWE systems.

Severity of ischemia/reperfusion injury accompanied with generation of reactive oxygen species is reduced by hypoxic preconditioning, the precise mechanisms of which are not completely understood. We found that cobalt-induced hypoxia-inducible factor-1α activity ameliorated suppression of cell growth caused by H2O2 through protecting mitochondrial DNA from oxidative damage.

Overpotentials included in electrochemical hydrogen pump is separated with using a reference electrode. Separation result shows that non-ohmic overpotential in cathode is larger than that in anode. This result is also confirmed by electrochemical impedance spectra measurement, which shows impedance spectra of cathode is larger than that of anode. Volmer-Heyrovsky-Tafel mechanism is used to explain the separation result. Simulation result with using this mechanism suggests that reactions in anode and cathode are dominated by different mechanisms, and reaction rate of cathode is 2 orders of magnitude slower than that of anode.

In the planar SOFCs, the fuel/oxidant distributions and current collecting resistance cause current and temperature distributions over the electrodes under the separator ribs and flow channels. Optimized design of the separator is hence required to improve the output power and chemical/thermo-mechanical durabilities of practical stacks. To clarify the distributions, we prepare planar cells having three segmented cathodes. Current-voltage characteristics are measured with voltage control using three electric loads to reproduce the electrode potentials of a single cell at around 800°C. We find significantly small in-plane oxygen transport rate under the cathode rib and higher current collecting resistance under the channel. Increased anode rib width gives large overpotential under the rib due to fuel starvation. Finite element modeling supports the above experimental results. We demonstrate an improved separator design of a practical stack, taking advantage of this model. Thereby ca. 17% higher maximum power is given in the finite element simulation.

When solid polymer water electrolyzer (SPWE) is operated under high pressure conditions, large pressure difference forms between anode and cathode. It causes crossover of produced gas, especially for hydrogen gas, and decreases current efficiency of SPWE. Supplying water into cathode channel, in addition to anode, is a countermeasure to suppress the crossover, because the water flow improves to drain the hydrogen gas outside of cell, resulting in a decrease of the crossover and increase of the efficiency. This countermeasure for the crossover is evaluated by a SPWE operation under 2 MPa condition with visualization of hydrogen bubbles in cathode channel. The evaluation revealed that supplying water into cathode channel increases the efficiency by several percent under 0.33 A/cm2. Enhanced detachment of hydrogen bubbles from the surface of current supplier was confirmed by the visualization. It is suggested that this enhancement increases the efficiency.

Hydrogen gas is compressed with a new electrochemical pump, where internal humidifier is built in, and dead-end at anode is considered for a practical situation. Both the voltage and current efficiency of the hydrogen pump is evaluated experimentally. The pump is operated up to 2 MPa under the temperature condition of 293 and 333 K. The voltage efficiency indicates nearly 50% at most and the current efficiency is over 90%. Overpotentials inherently involved in the pump are discussed with electrochemical impedance spectroscopy.

Efficient cold start of PEFC under freezing point can be realized by keeping the super-cooled state of generated water. If a condition is satisfied, the cell can start under a freezing point with generated heat, and the cell reaches a steady state without the gas-supply block caused by the ice from the generated water. Moreover, difficult task, such as a shorter cold-start at a lower temperature, is possible by adequate choice of component material used in the cell, and by active heat generation with a suppressed air supply. Against such a background, this paper discussed which characteristic of the component in cell leads to the success of cold start, namely of keeping super-cooled state during cold start. This analysis was performed on the basis of heterogeneous nucleation theory which considers the wettability of surface of the component material.

Sulfur poisoning effect on the electrochemical performance and long-term durability of SOFC cathodes has been investigated for (La0.8Sr0.2)0.98MnO3 (LSM) and La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) up to 1000 hours. Gradual degradation of performance occurred, associated with the formation of strontium sulfate, which depended on SO2 concentration.

Sulfur species are major impurities in practical hydrocarbon-based-fuels, chemisorption of which on Ni anode catalysts results in possible performance degradation of SOFC systems. In the present study, degradation of SOFC performance caused by sulfur in pre-reformed CH4 has been evaluated under various operational conditions such as current density, fuel utilization, pre-reforming ratio, steam-to-carbon ratio, and operational temperature.

Long-term durability is one of the most important technological issues for SOFC system development. Life time of SOFCs can be critically affected by foreign species, including impurities and minor constituents in fuels and oxidants, from the raw materials of cell components, and from system components. This paper summarizes an effort to understand the impurity poisoning analyzed by adding specific impurity species into fuels under various operational conditions to clarify poisoning mechanisms and their concentration threshold. Possible acceleration procedures for poisoning phenomena have also been discussed.

Temperature distribution in the through-plane direction in polymer electrolyte fuel cell (PEFC) is key information to achieve proper water management. We fabricated an in-line thermocouple of 49 μm diameter, insulated by Parylene coating with 12 μm thickness. The supporter for the thermocouple was fabricated to position the thermocouple to an exact measurement-point in cell, and to protect the thermocouples from the damage during assembling and operating the cell. Seven in-line thermocouples were placed in the cell in array. It was found that the insertion of thermocouples did not cause large decrease of the cell performance. When the current of 0.3 A/cm2 was loaded under the condition of 60 {degree sign}C separator temperature with supplying H2/Air humidified at 80 % RH, the cathode catalyst layer temperature showed the increase of 1.9 {degree sign}C and the maximum in the cell.

Various additives for Ni anodes mixed with ScSZ prepared by spray mist dryer are examined for SOFCs in order to improve their anodic activity and long-term durability. Among the additives examined, it is found that the addition of Mn was highly effective to improve anode activity and sulfur tolerance. In case 5 mol% Mn was added to Ni, at 800 oC and 200 mA/cm2 for 50 % pre-reformed CH4 fuels (S/C = 2.5), the initial cell voltage drop by 5 ppm H2S was ca. 30 mV, which was less than half of the initial cell voltage drop for undoped Ni-cermet anodes. Mn-oxide reacts with NiO during preparation, while Ni metal nanoparticles will be segregated after reduction and Mn-oxide acts as pinning sites to depress grain growth and agglomeration of Ni particles, leading to lower anodic overvoltage and higher sulfur tolerance. Long-term durability up to 3000 hours has been verified.

This paper reports the chemical degradation of Ni-based SOFC anodes caused by small amounts of impurities supplied with fuels. In particular, the impurity dependence of degradation behaviors as well as poisoning mechanisms are highlighted and investigated. Poisoning effects by chlorine and siloxanes are found to be critical to achieve satisfactory SOFC durability. In addition, it has also been demonstrated that phosphorus and boron compounds led to gradual decrease in cell voltage, Ni grain growth, and even formation of nickel phosphates. The measured trends are discussed in relation to the thermochemical calculations and FESEM/STEM-EDX analysis.

The influences of SO2 and water vapor in air were investigated for (La0.8Sr0.2)0.98MnO3 (LSM) and La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) cathodes by measuring cell voltage at a constant current density of 200 mA cm-2 and the operational temperature of 800 oC. The results of 1000 h durability tests suggest that SO2 and water vapor in the ambient air little affect the performance of both cathode materials under typical operational conditions.