Electrochemical analysis of hydrogen membrane fuel cells

An electrochemical analysis was conducted with respect to a hydrogen membrane fuel cell with SrZr_0.8In_0.2O_3−δ electrolyte, which is a new type of fuel cell featuring an ultra-thin proton conductor supported on a dense metal anode. Most of the voltage loss derives from the cathode and the electrolyte, and a small amount of anode polarization was observed only in regions with high current density. The cathode polarization was approximately an order of magnitude lower than that of SOFCs. Furthermore, the conductivity of the film electrolyte was almost identical to that of the sinter at 600 °C; however, it was several times as large at 400 °C. A TEM micrograph revealed that the film electrolyte consists mainly of long columnar crystals, and this crystal structure can be related to the conductivity enhancement below 600 °C.     

Depassivation-repassivation behavior of type-312L stainless steel in NaCl solution investigated by the micro-indentation

Repassivation behavior of type-312L stainless steel containing 6% of molybdenum was examined in NaCl solution using in situ micro-indentation technique, together with type-304 and 316L stainless steels. High stability of the passive film formed on the type-312L stainless steel was also examined by depth profiling analysis of passive films using glow discharge optical emission spectroscopy (GDOES). In 0.9 mol dm⁻³ NaCl solution at 296 K the type-304 and 316L stainless steels are passive only up to 0.3 V (SHE), above which pitting corrosion occurs. In contrast, no pitting corrosion occurs on type-312L stainless steel. Despite the significant difference of the pitting corrosion resistance, the repassivation kinetics of the three stainless steels, examined by micro-indentation at 0.3 V (SHE), is similar. The presence of molybdenum in the stainless steel does not influence the repassivation kinetics. The charge required to repassivate the ruptured type-312L stainless steel surface increases approximately linearly with the potential, even though the passivity-maintaining current increased markedly at potentials close to the transpassive region. Repassivation occurs without accompanying significant dissolution of steel, regardless of the stability of passive state. Depth profiling analyses of the passive films on the type-312L stainless steels formed at several potentials revealed that molybdenum species enrich in the outer layer of the passive film, below which chromium-enriched layer is present. The permeation of chloride ions may be impeded by the outer layer containing molybdate, enhancing the resistance against the localized corrosion of the type-312L stainless steel.     

Impact of noble rot on the aroma precursor of 3-sulfanylhexanol content in Vitis vinifera L. cv Sauvignon blanc and Semillon grape juice

The most famous sweet wine in France is made from botrytised grapes in the Sauternes region. Its distinctive, complex aromas are undoubtedly due to noble rot as a result of Botrytis cinerea development on perfectly ripe Sauvignon blanc and Semillon grapes. The contribution of volatile thiols in botrytised wine aroma was recently reported. The objective of this work was to investigate the impact of B. cinerea development on the aromatic potential of grape juice. The level of S-3-(hexan-1-ol)cysteine (P-3SH), the cysteinylated precursor of the most abundant volatile thiol in wine (3-sulfanylhexanol, 3SH), was determined during grape botrytisation and several grape overripening processes. Production was considerably amplified when B. cinerea had developed on the grapes in both on- and off-vine experiments. The P-3SH levels were increased about 100-fold between the healthy and botrytised stages in one week. We demonstrated that the grape metabolism produced aroma precursor under post-harvest conditions. When grapes were left to overrippen, the vine also produced P-3SH, but levels increased more moderately (about 10-fold). Moreover, a determination of P-3SH distribution demonstrated that B. cinerea was not directly responsible for precursor formation but probably stimulated the grape metabolic pathway involved in this formation.     

Automatic identification of bone erosions in rheumatoid arthritis from hand radiographs based on deep convolutional neural network

Although radiographic assessment of joint damage is essential in characterizing disease progression and prognosis in patients with rheumatoid arthritis (RA), it is often difficult even for trained radiologists to find radiographic changes on hand and foot radiographs because lesion changes are often subtle. This paper proposes a novel quantitative method for automatically detecting bone erosion on hand radiographs to assist radiologists. First, the proposed method performs with the crude segmentation of phalanges regions from hand radiograph and extracts the detailed phalanges regions by the multiscale gradient vector flow (MSGVF) Snakes method. Subsequently, the region of interest (ROI; 40?×?40 pixels) is automatically set on the contour line of the segmented phalanges by the MSVGF algorithm. Finally, these selected ROIs are identified by the presence or absence of bone erosion using a deep convolutional neural network classifier. This proposed method is applied to the hand radiographs of 30 cases with RA. The true-positive rate and the false-positive rate of the proposed method are 80.5% and 0.84%, respectively. The number of false-positive ROIs is 3.3 per case. We believe that the proposed method is useful for supporting radiologists in imaging diagnosis of RA.

     

Diverse reports recommendation system based on latent Dirichlet allocation

Behaviormetrika - This paper presents a proposal for system supporting learners in improving their report-writing skills by recommending reports from previous learners. The proposed system...     

Thermal Characterization of the Gelatinization of Corn Starch Suspensions with Added Sodium Hydroxide or Urea as a Main Component of Corrugating Adhesives

The effects of sodium hydroxide and urea on the gelatinization of corn starch suspensions, a main component of corrugating starch adhesives, were studied using differential scanning calorimetry (DSC). Sodium hydroxide and urea decreased the gelatinization starting temperature (T_s1), peak temperature, conclusion temperature, enthalpy of gelatinization (DSCΔH), apparent activation energy (ApEa), and van’t Hoff enthalpy change (ΔH_vHº). DSC analysis showed the gelatinization endotherm, the melting endotherm of starch−lipid complexes, and an exotherm attributable to the alkali-decomposition of starch. This exotherm was only observed in the first scan for sodium hydroxide additions of more than 3.8 mol%. The existence of the starch−lipid complexes was also suggested by the reappearance of the corresponding endotherm in the second DSC scan. The increases in the gelatinization rate constants caused by the two additives were deduced from the Arrhenius equation using ApEa. The relationship between the temperature corresponding to the half gelatinization transition (T_m) and DSCΔH, and that between T_mand ApEa quantitatively agreed for the two additives, suggesting that gelatinization might be stimulated by a similar mechanism involving breaking intermolecular hydrogen bonds in starch. Only sodium hydroxide caused a significant decrease of T_s1 and broadening of the gelatinization peak. Therefore, ΔH_vHºand the size of the gelatinizing cooperative unit estimated from the ΔH_vHº/DSCΔH ratio were decreased more by sodium hydroxide than by urea, indicating that sodium hydroxide facilitated the mobility of starch molecules more effectively during gelatinization.     

Stress and rock mechanics issues of relevance to HDR/HWR engineered geothermal systems: review of developments during the past 15 years

This paper reports the findings of the Stress and rock mechanics working group of the Academic Review of Hot Dry Rock/Hot Wet Rock (HDR/HWR) Engineered Geothermal Systems convened in Sendai, Japan in 1997. Key developments in the fields of stress and rock mechanics that are relevant to the development of HDR/HWR systems and that have occurred since the last Academic Review in 1982 are described. Rock mechanics is here taken to include basic studies of fluid flow through fractures. Key unresolved issues that are important for HDR/HWR systems are also discussed.     

Effect of film thickness on electrical property of microcrystalline silicon

We report dependences of electrical properties on SiH₄/H₂ dilution rate and film thickness for microcrystalline silicon films formed by a hydrogen radical-induced chemical vapor deposition (HRCVD) method. The electrical conductivity of the films at SiH₄ 18 sccm /H₂ 120 sccm was markedly increased to 10⁻³ S/cm as film thickness increased above 100 nm. Crystalline grains with (2 2 0) orientation were formed. Theoretical analysis revealed that grain boundaries among (2 2 0) grains had a low defect density of 1×10¹² cm⁻² so that the high conductivity was achieved.