162 research outputs found

    Importance of Acid–Base Equilibrium in Electrocatalytic Oxidation of Formic Acid on Platinum

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    This work was supported by Japanese Society for the Promotion of Science (JSPS) KAKENHI Grants Nos. 24550143 and 24750117 and MEXT Project of Integrated Research on Chemical Synthesis. M.T.M.K. gratefully acknowledges the award of Long-Term Fellowship of JSPS (No. L-11527) and Visiting Professorship of Hokkaido University. T.U. acknowledges Grants-in-Aid for Regional R&D Proposal-Based Program from Northern Advancement Center for Science & Technology of Hokkaido, Japan. J.J. acknowledges scholarship of Asian Graduate School, Hokkaido University.Peer reviewedPostprin

    Testing applicability of image analysis for measurements of sediment concentration in laboratory experiments

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    Flume experiments are typically conducted to reveal the detailed behavior of debris flows. Direct sampling at the lower end of a flume has been used to measure sediment concentrations in flume experiments; however, direct sampling measurements under non-steady or non-equilibrium conditions are difficult. In contrast, image analysis methods can acquire spatiotemporal high-resolution data in a non-contact manner. In this study, we conducted experiments in which a homogenous sediment concentration field of 0 ~ 20 % was prepared in a water tank with a depth of 10 cm using coarse and fine sediments. We filmed the experiments and verified the relationships between sediment concentrations and image features in a fixed area. As a result, the mean of pixel values for coarse sediments depends on the sediment concentration of up to 10 % and the number of mode pixels for fine sediments depends on the sediment concentration of up to 20 %. We then analyzed factors influencing image features and identified three processes. Furthermore, we analyzed the effects of the sediment grain size on image features, and the results show that both the brightness index and brightness uniformity index of images are affected. In conclusion, these findings indicate that image analysis can be used to clarify both sediment concentration and grain size

    Spatial Variation in Specific Sediment Discharge Volume from First-Order Catchment due to Heavy Rainfall and its Factors

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    In this study, we evaluated the variations in sediment discharge between basins from the first- order catchment of the Akatani River watershed, where sediment discharges as a result of heavy rainfall. We tested the correlation between sediment discharge, topography, and rainfall magnitude using LiDAR datasets. The results showed that the specific eroded sediment volume in the first-order catchment was sufficiently greater than the specific deposited sediment volume, and the variation of the specific discharge sediment volume from the first-order catchment was determined by the variation of the specific eroded sediment volume. The spatial variations of specific discharged sediment volumes could not be evaluated solely by topography and rainfall indices; even in the catchment, where the topographic condition and rainfall magnitude were almost the same, the specific sediment discharge varied by more than one magnitude

    Olmesartan and temocapril prevented the development of hyperglycemia and the deterioration of pancreatic islet morphology in Otsuka-long-evans-Tokushima Fatty rats

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    We investigated the impact of olmesartan and temocapril on pancreatic islet beta-cells during the development of diabetes mellitus using Otsuka-Long-Evans-Tokushima Fatty (OLETF) rats. Four-week-old male OLETF rats were fed standard chow (untreated:n5), or chow containing either 0.005% olmesartan(n5) or 0.01% temocapril (n5) until being sacrificed at 35 weeks of age. Pancreas sections were double-stained with anti-insulin and anti-glucagon antibodies. The percent areas of beta-cells, alpha-cells and non-alpha-non-beta-cells were compared among groups. In untreated OLETF rats, the fasting plasma glucose (FPG) level was elevated at the 18th week and remained elevated until the 35th week. On the other hand, no significant elevation in FPG levels was observed in olmesartan- or temocapril-treated rats. Pancreatic islets from olmesartan-treated rats were significantly smaller in size as compared with those from untreated OLETF rats. Furthermore, the average area occupied by beta-cells as a fraction of the total area of an individual islet was significantly higher in olmesartan- or temocapril-treated rats than that in untreated OLETF rats. Olmesartan and temocapril both prevented the development of hyperglycemia, possibly through the prevention of islet beta-cell loss in spontaneously diabetic OLETF rats.</p

    How are fine sediments described in sediment sheet flow?

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    Stony debris flow transits to sediment sheet flow when the river bed gradient becomes gentle. The sediment sheet flow consists of a water flow layer and a sediment moving layer. Fine sediments are expected to behave as a part of the fluid rather than a solid phase in the sediment moving layer. Further, it can be thought that a part of fine sediment can be suspended in the water flow layer. However, it was not possible to physically express whether the fine sediment behaves as a solid phase or a fluid phase in the numerical simulation model. Here we physically modeled fine sediment behavior in sediment sheet flow. We confirmed the applicability of the new model to describe the longitudinal deposited sediment gradient in flume experiments

    Strongly Blueshifted Phenomena Observed with {\it Hinode}/EIS in the 2006 December 13 Solar Flare

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    We present a detailed examination of strongly blueshifted emission lines observed with the EUV Imaging Spectrometer on board the {\it Hinode} satellite. We found two kinds of blueshifted phenomenon associated with the X3.4 flare that occurred on 2006 December 13. One was related to a plasmoid ejection seen in soft X-rays. It was very bright in all the lines used for the observations. The other was associated with the faint arc-shaped ejection seen in soft X-rays. The soft X-ray ejection is thought to be an MHD fast-mode shock wave. This is therefore the first spectroscopic observation of an MHD fast-mode shock wave associated with a flare.Comment: 18 pages, 1 table, 6 figures. ApJ, accepte
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