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Abstract To elucidate the gas generation mechanism due to electrolyte decomposition in commercial lithium-ion cells after long cycling, we developed a device which can accurately determine the volume of generated gas in the cell. Experiments on LixC6/Li1−xCoO2 cells using electrolytes such as 1 M LiPF6 in propylene carbonate (PC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are presented and discussed. In the nominal voltage range (4.2–2.5 V), compositional change due mainly to ester exchange reaction occurs, and gaseous products in the cell are little. Generated gas volume and compositional change in the electrolyte are detected largely in overcharged cells, and we discussed that gas generation due to electrolyte decomposition involves different decomposition reactions in overcharged and overdischarged cells.

Proton conducting ceramics (PCC) cells are promising energy conversion devices that enable high efficiency energy conversion at lower temperature range, solving the challenge of conventional solid oxide cells (SOCs) due to the high operating temperature. Electrochemical performance and chemical stability of PCC electrolyte has been investigated in recent studies, suggesting that rare-earth doped Ba(Zr,Ce)O3 perovskite-type ceramics are optimal materials exhibiting high proton conductivity and chemical stability during operations. On the contrary, mechanical stability of these PCC electrolyte materials has not been evaluated despite the fact that the mechanical properties are critically important for achieving long-term stable operation as fuel cells or electrolyser cells. For the development of conventional SOCs, mechanical stability during high temperature operation was one of the most significant challenges to deal with, which was attained as a result of detailed studies on in-situ elastic properties of composing materials such as oxygen ion conducting electrolytes and residual stresses. Similarly, for PCC cells, mechanical properties of cells and composing materials have been of significant interest in order to achieve mechanically stable long-term operation, even though PCC cells operate at lower temperature than SOCs. Furthermore, the metal-supported (MS) structure which provides superior mechanical robustness compared to anode-supported (AS) structure is expected to be applied effectively to PCC cells, which are called proton conducting ceramics – metal-supported cells (PCC-MSCs), leading to greater necessity of the mechanical evaluation of the cells and composing materials. Electrolyte is the most crucial component in an electrochemical cell and must be mechanically stable because ion transport and gas tightness made by electrolyte determines electrical performance. However, there has been important concern that larger thermal stresses might be introduced in PCC cells compared to SOCs, resulting from the thermal expansion coefficient (TEC) mismatch between the electrode and electrolyte and from the chemical expansion by the hydration that occurs in a certain temperature range. The PCC electrolyte is highly in need of investigation on in-situ mechanical properties, especially on elastic properties. In this study, elastic properties of electrochemically promising PCC, Y-doped Ba(Zr,Ce)O3 perovskite-type ceramics, were investigated under high temperature conditions. Elastic moduli such as Young’s modulus and Poisson’s ratio were measured by the method that we previously developed for elastic investigation in high temperature conditions using ultrasonic waves. This method enables highly accurate and repetitive examination of elastic properties at high temperatures in materials with poor sinterability including PCC by measuring ultrasonic sound velocities in pellets typically fabricated for electrochemical tests. Pellets of BaZr1-xYxO3-δ (BZY) with different concentrations of doped yttrium, BaZr0.9Y0.1O3-δ (BZY10), BaZr0.85Y0.15O3-δ (BZY15), and BaZr0.8Y0.2O3-δ (BZY20), were fabricated. Additionally, pellets of BaZryCe1-yY0.1O3-δ (BZCY) with different ratio of Ce to Zr, BaZr0.7Ce0.2Y0.1O3-δ (BZCY721) and BaZr0.8Ce0.1Y0.1O3-δ (BZCY811) were fabricated. Powders of PCCs above were consolidated to be thick rounded shape and sintered in air. Each prepared sample was set in an electric furnace in laboratory air atmosphere and sound velocities were measured with the sample slowly heated up to 700 °C and subsequently cooled down to room temperature to calculate elastic moduli at each measuring point. In the first series of heating and cooling measurements for as-sintered samples, hysteresis on elastic moduli in intermediate temperature range was observed. We repeatedly conducted a series of heating and cooling measurements several times, and then the hysteresis was not observed any further. Fig.1 shows final state Young’s modulus of BZCY721, BZCY811, and BZY10 (BZCY901) without hysteresis. Elastic moduli at room temperature have not changed through multiple heating and cooling measurements, and crystal structures and lattice parameters were also confirmed to remain constant by x-ray diffraction (XRD) analysis. The hysteresis found in a specific temperature range suggests that elastic moduli were influenced presumably by a change in defect structure of PCC caused by hydration or defect association of oxygen vacancies and dopants. At room temperature, Young’s modulus decreased with the increment of Ce concentration by 16 % from BZY10 to BZCY721. When materials have the same crystalline structure, Young’s modulus generally decreases as mean atomic volume of the base crystal increases. Because BaCeO3 has larger mean atomic volume than BaZrO3, this observation is qualitatively reasonable. However, in high temperatures, the difference became significant only for BZCY721, Young’s modulus decreased by 30 % from that at room temperature in BZCY721. These results suggest that Ce substitution causes different high temperature dependences. Figure 1

Abstract Rice husk (RH), an agricultural waste, is abundantly available in rice producing countries like China, India, Bangladesh, Brazil, US, Cambodia, Vietnam, Myanmar, and South East Asia. Despite the massive amount of annual production worldwide, so far RHs have been recycled only for low-value applications. In recent years, many rice mills in rice producing countries have started using RH for the energy production for mill operations as well as household lighting in rural regions. Burning of RHs produces the rice husk ash (RHA). The disposal in landfills or open fields can be problematic and may cause a serious environmental and human health related problems due to the low bulk density of RHA. Several ways are being thought of for disposing RHA by making its commercial use. The amorphous silica forms the main component (83–90%) of RHA. The amorphous silica rich RHA has wide range of applications. High-value applications and current research investigations such as the use of RHA in manufacturing of silica gels, silicon chip, synthesis of activated carbon and silica, production of light weight construction materials and insulation, catalysts, zeolites, ingredients for lithium ion batteries, graphene, energy storage/capacitor, carbon capture, and in drug delivery vehicles are presented. Use of RHA in potential future applications is also discussed. It is suggested that the amorphous silica rich RHA could become a potential resource of low cost precursor for the production of value-added silica based materials for practical applications.

Taraxacum coreanum Nakai has been traditionally used for treating inflammatory diseases including gastrointestinal diseases.We studied whether water extracts of Taraxacum coreanum Nakai (TCN) had a protective effect on acute and chronic gastritis induced by ethanol/HCl in an animal model of gastritis and its mechanism was also explored.In the acute study, rats were orally administered 0.15g/mL dextrin (normal-control), 0.15g/mL dextrin (control), 0.05g/mL TCN (TCN-L), 0.15g/mL TCN (TCN-H), or 0.01g/mL omeprazole (orally; positive-control), followed by oral administration of 1mL of 60% ethanol plus 150mM HCl (inducer). In the chronic study, rats were administered 10% diluted inducer in drinking water, and 0.6% dextrin, 0.2% or 0.6% TCN, and 0.05% omeprazole were administered in chow for 4 weeks. Acid content, gastric structure, oxidative stress, and markers of inflammation in the stomach tissue were measured at the end of experiment.Acute and chronic ethanol/HCl administration caused the inner layer of the stomach to redden, hemorrhage, and edema in the control group; TCN-H reduced these symptoms more effectively than did the omeprazole positive-control. Acid production and total acidity in the stomach increased in the control group, which was markedly suppressed by omeprazole. TCN also reduced the acid production and acidity, but not to the same degree as omeprazole. H-E and PAS staining revealed that in the inner layer of the stomach, cellular structure was disrupted, with an increased nuclear size and thickness, disarrangement, and decreased mucin in the control group. TCN prevented the cellular disruption in the inner layer, and TCN-H was more effective than the positive-control. This was associated with oxidative stress and inflammation. TCN dose-dependently reduced the infiltration of mast cells and TNF-α expression in the inner layer of the stomach, and decreased lipid peroxides by increasing superoxide dismutase and glutathione peroxidase expression.TCN-H acutely and chronically protected against gastritis and gastric ulcer by reducing oxidative stress and inflammation, not by completely suppressing gastric acid production.

Abstract Sodium-promoted vanadium oxide catalysts supported on MCM-41 and TiO 2 (anatase) were investigated for the partial oxidation of ethanol to acetaldehyde. The catalysts were prepared by incipient wetness impregnation with a vanadium oxide content of 6 wt.%. The experimental characterization was performed by X-ray diffraction (XRD), N 2 adsorption, temperature-programmed reduction (TPR), and diffuse reflectance UV–vis. Temperature-programmed oxidation (TPO) was also used to identify carbon deposits on the spent catalysts. The presence of sodium plays a strong role in the dispersion and reducibility of the vanadium species as detected by TPR analysis and optical absorption spectroscopy. While sodium addition increases the dispersion of the VO x species, its presence also decreases their reducibility. Additionally, TPO of the spent catalysts revealed that an increase in the Na loading decreases the carbon deposition during reaction. In the case of the catalysts supported on MCM-41, these modifications were mirrored by a change in the activity and selectivity to acetaldehyde. Additionally, on the VO x /TiO 2 catalysts the catalytic activity decreased with increasing sodium content in the catalyst . A model in which sodium affects dispersion, reducibility and also acidity of the supported-vanadia species is proposed to explain all these observations.

AbstractWe report on the synthesis and characterization of an electrospun gel polymer electrolyte (GPE) membrane based on polyacrylonitrile nanofibers (PAN) swollen in a polyethylene glycol dimethyl ether/Na‐salt electrolyte solution, for application in room temperature sodium–sulfur (Na–S) batteries. The membranes show a high ionic conductivity, wide electrochemical stability window, and good thermal stability. We demonstrate the performance of the membrane in an Na–S cell using a sulfur–carbon nanotubes composite cathode and Na metal as anode. Our results show that the GPE membrane stabilizes the Na metal anode resulting in stable cycling behavior. The capacity of the Na–S cell, using the GPE membrane and operating at room temperature, is approximately 500 mAh g−1 over 40 cycles. The selected electrolyte configuration also provides improved safety by replacing the highly reactive sodium perchlorate (NaClO4) salt previously used in literature. All these benefits make the gel‐polymer electrolyte membrane a very promising system for application in room‐temperature sodium and sodium–sulfur batteries.

The effects of redox potential and electric charge on the rate of electron-transfer reaction by a two-electron process were investigated. For electron donors, beta-NADH, beta-NADPH and alpha-NADH were used; they have similar structures but different charges and different redox potentials. For electron acceptors, the following 5-ethylphenazine derivatives were used: 1-(3-carboxypropyloxy)-5-ethylphenazine, 1-(3-ethoxycarbonylpropyloxy)-5-ethylphenazine, and 1-[N-(2-aminoethyl)carbamoylpropyloxy]-5-ethylphenazine. They have similar structures and different charges. Using these donors and acceptors, the potential and the charge effects were estimated separately. In the potential effect, a linear free energy relationship was observed for the change in the redox potential of the donor with a Brønsted slope of about unity. On the other hand, the slope for the change in the potential of the acceptor was about 0.5. These results show that the potential effect due to electron donors is different from that due to electron acceptors. A linear relationship was also observed between activation free energy and electrostatic force (or potential). The redox potential effect and the electrostatic effect are independent and additive. New theory for the mechanism of electron-transfer reactions is needed to explain these results.

ADP ribosylation is considered one of the important covalent modifications of cellular proteins catalyzed by ADP ribosyltransferase, which transfers ADP ribose moiety of NAD to an acceptor protein. Because a growing body of evidence has suggested significant biological roles for mono-ADP ribosylations in transmembrane signal transduction and other cell metabolism, how alcohol intake alters them is of interest. Cholera toxin and pertussis toxin have been widely used as probes to investigate the roles of GTP-binding proteins (G-proteins) in the transduction of hormonal and sensory signals. We first tested effects of long-term alcohol intake on these toxin-catalyzed ADP ribosylations of G-proteins in rat liver plasma membranes. Treatment of rat liver plasma membrane with [32P]NAD and thiol-preactivated cholera toxin resulted in the labeling of a 44-kD band, most likely an α-subunit of the stimulatory GTP-binding protein, the extent of which was much greater in alcohol-fed rats than in pair-fed controls. Analogous experiments with pertussis toxin also demonstrated enhancement of toxin-catalyzed ADP ribosylation of the inhibitory GTP-binding protein after long-term alcohol intake. More interesting was that long-term alcohol intake remarkably stimulated endogenous mono-ADP ribosylation of a 58-kD protein in a GTP-dependent manner. In vitro, ethanol (50 mmol/L) or a single load of ethanol (3 gm/kg) did not stimulate the reaction. Thus long-term alcohol intake stimulated both toxin-catalyzed and endogenous mono-ADP ribosylations of proteins in rat liver plasma membranes. Pursuit of alcohol interaction with mono-ADP ribosylation may provide an interesting approach to the study of alcohol's effects on the liver. (HEPATOLOGY 1993;18:870-873).

The current study was carried out with particular emphasis on the association between phonetic function tests and alterations in the appearance of the hypopharyngeal and laryngeal mucosa, such as capillary dilatation, edema, and vocal fold injection after alcohol intake. The results demonstrated the occurrence of previously unrecognized pathophysiological changes associated with synchronous phonetic functions in the vocal pathway after alcohol intake. Serum ethanol and aldehyde concentration levels were evaluated hourly for 2.5 h after ingestion of alcohol. When an electronystagmogram showed the typical pattern of alcohol intake, the study was initiated. Occasionally, rhinography was performed on subjects complaining of a stuffy nose after alcohol intake.