Hydrogen production through dry reforming of biogas using a porous electrochemical cell: Effects of a cobalt catalyst in the electrode and mixing of air with biogas

This paper reports the performance of porous Gd-doped ceria (GDC) electrochemical cells with Co metal in both electrodes (cell No. 1) and with Ni metal in the cathode and Co metal in the anode (cell No. 2) for CO₂ decomposition, CH₄ decomposition, and the dry reforming reaction of a biogas with CO₂ gas (CH₄ + CO₂ → 2H₂ + 2CO) or with O₂ gas in air (3CH₄ +?1.875CO₂ +?1.314O₂ → 6H₂ +?4.875CO +?0.7515O₂). GDC cell No. 1 produced H₂ gas at formation rates of 0.055 and 0.33?mL-H₂/(min?m²-electrode) per 1?mL-supplied gas/(min?m²-electrode) at 600?°C and 800?°C, respectively, by the reforming of the biogas with CO₂ gas. Similarly, cell No. 2 produced H₂ gas at formation rates of 0.40?mL-H₂/(min?m²) per 1?mL-supplied gas/(min?m²) at 800?°C from a mixture of biogas and CO₂ gas. The dry reforming of a real biogas with CO₂ or O₂ gas at 800?°C proceeded thermodynamically over the Co or Ni metal catalyst in the cathode of the porous GDC cell. Faraday's law controlled the dry reforming rate of the biogas at 600?°C in cell No. 2. This paper also clarifies the influence of carbon deposition, which originates from CH₄ pyrolysis (CH₄ → C + 2H₂) and disproportionation of CO gas (2CO → C + CO₂), on the cell performance during dry reforming. The dry reforming of a biogas with O₂ molecules from air exhibits high durability because of the oxidation of the deposited carbon by supplied air.     

DETERMINATION OF PALAEOSTRESSES FROM MESOSCALE SHEAR FRACTURES IN CORE SAMPLES USING THE MULTI-INVERSE METHOD

Palaeostress reconstruction is the key to quantitative characterization of fractured hydrocarbon reservoirs. In order to calculate the palaeostresses responsible for fault activity, faults in oriented core samples can be analysed and the optimal stresses can then be determined from fault-slip data in a least-squares sense. Many fractured reservoir rocks, however, include faults generated during a number of different tectonic phases. In these cases, the optimal stresses can be determined for subgroups of faults which are considered to be of approximately the same age. The difficulty with this is that criteria for accurate age-dating are often absent, especially from core samples.
Recently, the so-called "multi-inverse" method has been proposed to address this problem. This is a numerical technique for separating palaeostresses within a heterogeneous fault assemblage in the absence of a priori information on the faults'relative ages. In this paper, we apply the method to eighteen faults in two short (9m) cores from an exploration well in Hokkaido, northern Japan. The cores came from a fractured hydrocarbon reservoir and were oriented by correlation with borehole images. Core lithologies included massive Cretaceous basalts in which there was no layering which would show fault offsets; for these samples, we determined the sense of shear by studying asymmetric microstructures on the fault surfaces. The results show that the rocks have experienced six different stress regimes. In general, these are compatible with the tectonic history of the study area as inferred from the regional stratigraphy and from macroscale geological structures.
These results show that the multi-inverse method can be used to extract palaeostress data from cores, thereby providing information which will assist with the exploration of (and production from) fractured hydrocarbon reservoirs.     

Effective lightning protection schemes for distribution line

The causes of lightning outage are subdivided into direct lightning strokes and induced lightning strokes, which are identified by the characteristics of the lightning overvoltage. In the past, lightning protection devices were directed mainly toward the latter, and attention has been focused on the installation of lightning protection devices, ground wires, and reinforcement of insulators. However, lightning outages continue to occur. Thus it is extremely important to clarify the fault characteristics of lightning surges and to study the effectiveness of various lightning protection devices by considering both direct lightning stroke and induced lightning stroke in order to prevent lightning outage in the future. In this research, the electromagnetic transients program (EMTP) has been applied to the direct lightning stroke, and the induced lightning outage analysis program for multiple conductor systems has been applied to the induced lightning stroke to study the effectiveness of lightning protection devices provided by combination of various lightning protection devices. The most effective lightning protection schemes are analyzed and evaluated based on verification tests on the full scale models as well as economic considerations.     

Changes in cerebral blood flow and oxygen metabolism related to magnetic resonance imaging white matter hyperintensities in Alzheimer's disease

We studied changes in cerebral perfusion and oxygen metabolism to elucidate the pathophysiological nature and clinical significance of white matter hyperintensities in Alzheimer's disease (AD). METHODS: Sixteen AD patients (age 71.6 +/- 3.1 yr) whose T2-weighted MR images showed white matter hyperintensities, and 16 age-matched AD patients (age 71.0 +/- 4.3 yr) without white matter hyperintensities were compared. Regional cerebral blood flow (CBF), oxygen metabolism (CMRO2) and oxygen extraction fraction (OEF) were measured by using (15)O steady-state method and PET. RESULTS: There was no significant difference in cognitive impairment between the two groups. Compared to the patients without white matter hyperintensities, those with them had significantly low CBF values and significantly high OEF values in all cortical and white matter regions. However, there were no significant differences in CMRO2 values between the two groups. Severity of white matter hyperintensities correlated with the mean cortical and mean white matter OEF. CONCLUSION: In AD patients, white matter hyperintensities on T2-weighted MR images represent ischemic changes in which oxygen metabolism and function are fairly compensated. These changes are not disease-specific but are age-associated coincidences, as in normal aging with or without vascular risk factors.     

Facile optical resolution of amino acid esters via hydrolysis by an industrial enzyme in organic solvents

Racemic amino acid esters were optically resolved via hydrolysis in organic solvents by the catalysis of an industrial alkaline protease, “Alcalase”. The products which were composed mainly of L-amino acids were insoluble and easily separated by filtration. The activity of the enzyme and enantiomeric excess of the products were significantly dependent on the nature of solvent and the water content in the reaction media. Generally, high values of enantiomeric excess were obtained at low water contents. Many natural and unnatural amino acids were resolved by this method.     

Identification of SYS1 as a Host Factor Required for Shiga Toxin-Mediated Cytotoxicity in Vero Cells

Shiga toxin (STx) or Vero toxin is a virulence factor produced by enterohemorrhagic Escherichia coli. The toxin binds to the glycosphingolipid globotriaosylceramide (Gb3) for its entry, and causes cell death by inhibiting ribosome function. Previously, we performed a loss-of-function screen in HeLa cells using a human CRISPR knockout (KO) library and identified various host genes required for STx-induced cell death. To determine whether this library targeted to the human genome is applicable to non-human primate cells and to identify previously unrecognized factors crucial for STx-induced cell death, we herein performed a similar screen in the African green monkey kidney-derived Vero C1008 subline. Many genes relevant to metabolic enzymes and membrane trafficking were enriched, although the number of enriched genes was less than that obtained in the screening for HeLa cells. Of note, several genes that had not been enriched in the previous screening were enriched: one of these genes was SYS1, which encodes a multi-spanning membrane protein in the Golgi apparatus. In SYS1 KO Vero cells, expression of Gb3 and sphingomyelin was decreased, while that of glucosylceramide and lactosylceramide was increased. In addition, loss of SYS1 inhibited the biosynthesis of protein glycans, deformed the Golgi apparatus, and perturbed the localization of trans-Golgi network protein (TGN) 46. These results indicate that the human CRISPR KO library is applicable to Vero cell lines, and SYS1 has a widespread effect on glycan biosynthesis via regulation of intra-Golgi and endosome–TGN retrograde transports.     

Synergic effect of Pd/γ-alumina and Cu/ZSM-5 on the performance of NO x storage reduction catalyst

NO _x reduction with a combination of catalysts, Pd catalyst, NO _x storage reduction (NSR) catalyst and Cu/ZSM-5 in turn, was investigated to elucidate for the high NO _x reduction activity of this catalyst combination under oxidative atmosphere with periodic deep rich operation. The catalytic activity was evaluated using the simulated exhaust gases with periodically fluctuation between oxidative and reductive atmospheres, and it was found that the NO _x reduction activity with this catalyst combination was apparently higher than that of the solely accumulation of these individual activities, which was caused by the additional synergic effect by this combination. The Pd catalyst upstream of the NSR catalyst improved NO _x storage ability by NO₂ formation under oxidative atmosphere. The stored NO _x was reduced to NH₃ on the NSR catalyst, and the generated NH₃ was adsorbed on Cu/ZSM-5 downstream of the NSR catalyst under the reductive atmosphere, and subsequently reacted with NO _x on the Cu/ZSM-5 under the oxidative atmosphere.     

Fracture toughness of silica particulate‐filled epoxy composite

The relationship between the postcuring conditions and fracture toughness on three silica particulate‐filled epoxy composites was investigated. The glass transition temperature, T_g, and the fragility parameter, m, derived from the thermo‐viscoelasticity, were used to characterize the composites, which were postcured under various conditions. The glass transition temperature and fragility both depended on both of the curing conditions and the volume fraction of silica particles. The glass transition temperature increased with the postcuring time and temperature, while the fragility generally decreased as the volume fraction increased. There was no direct correlation between the glass transition temperature and fragility. The fracture toughness depended on both the glass transition temperature and fragility. The composites with a high glass transition temperature and low fragility had high fracture toughness. These results indicate that the glass transition temperature and fragility are useful parameters for estimating the fracture toughness of the silica particulate‐filled epoxy composites. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2261–2265, 2002     

Fracture toughness of bisphenol A‐type epoxy resin

The relationship between the postcuring conditions and the fracture toughness of a bisphenol A‐type epoxy resin cured with acid anhydride was investigated. The glass transition temperature and fragility parameter, derived from the thermo‐viscoelasticity, were used to characterize the epoxy resin postcured under various conditions. Relationship between these two parameters and the fracture toughness was then investigated, based on the fractography results of a microscopic roughness examination of a fractured surface. The values of the glass transition temperature and fragility greatly depended on the postcuring conditions. The glass transition temperature was approximately 400 K when the crosslinking reaction was saturated. The fragility was independent of the saturation of the reaction and varied between 50 and 180. The results of the fracture test and fractography examination showed that there was no direct correlation between the glass transition temperature, the fracture toughness, and the roughness. On the other hand, there was a correlation between the fragility, fracture toughness, and roughness when the glass transition temperature saturated (at 400 K). As the fragility decreased from 180 to 50, the fracture toughness increased from 0.6 to 1.1 MPa · m^1/2 at the same glass transition temperature. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 10: 2266–2271, 2002     

Effects of growth temperature on the fatty acid composition of the free-living nematodeCaenorhabditis elegans

The effects of growth temperature on the fatty acid compositions of the phosphatidylcholine (PC), phosphatidylethanolamine (PE), and total lipid (TL) fractions of the free-living nematodeCaenorhabditis elegans were investigated. A reduction in growth temperature from 25 to 15°C caused the proportions of eicosapentaenoic acid (20∶5n-3) to increase from 23.6 to 32.5% in the PC, from 7.4 to 10.8% in the PE, and from 12.9 to 19.9% in the TL fractions. Conversely, the levels of dihomo-γ-linolenic acid (20∶3n-6) and arachidonic acid (20∶4n-6) in these phospholipid fractions and the TL fraction both decreased with decreasing growth temperature. Analysis of the positional distribution of fatty acids in the PC fraction revealed that the change in the composition of C₂₀ polyunsaturated fatty acid was obvious in positionsn-2. Lowering the growth temperature induced an increase in the level of the diacyl subclass of PE from 58% at 25°C to 71% at 15°C, with a concomitant decrease in the levels of the alkylacyl and alkenylacyl subclass of PE ofC. elegans. These changes observed in the phospholipids ofC. elegans might be one mechanism for adaptation to low temperature. Lipids 31, 1173–1178 (1996).