Structure of Duplex Multilayer Pb(Zr0.53Ti0.47)O3> Films Prepared by Sol-Gel Processing

Multilayer PZT films were prepared by sol-gel processing, and their structure and composition were investigated by cross-sectional TEM and EDX analyses. The films made by firing at 600°C (as-deposited films) are composed of alternating porous and dense layers, and the porosity increases by a factor of 2 through heating at 750°C. The pyrochlore phase observed in the as-deposited films turns to the perovskite phase by the heat treatment at 750°C. The Ti/Zr ratio along the film stacking direction is shown to change with the elevation of heat treatment temperature. The porous soft layers are considered to reduce the thermal stress and prevent the introduction of cracks during the firing process.     

Grain growth prediction based on data assimilation by implementing 4DVar on multi-phase-field model

We propose a method to predict grain growth based on data assimilation by using a four-dimensional variational method (4DVar). When implemented on a multi-phase-field model, the proposed method allows us to calculate the predicted grain structures and uncertainties in them that depend on the quality and quantity of the observational data. We confirm through numerical tests involving synthetic data that the proposed method correctly reproduces the true phase-field assumed in advance. Furthermore, it successfully quantifies uncertainties in the predicted grain structures, where such uncertainty quantifications provide valuable information to optimize the experimental design.     

Microstructure design of lead-free piezoelectric ceramics

Computational and experimental methodologies are integrated into a novel combined technique to define microstructure design criteria and maximize the properties of rhombohedral Bi_0.5Na_0.4K_0.1TiO₃, from untextured (1 MRD), d₃₃ = 155 pC/N, to textured (4.41 MRDs), d₃₃ = 227 pC/N. Two-dimensional orientation maps obtained using electron backscatter diffraction on sequential parallel layers are used to computationally reconstruct three-dimensional samples, simulate the local piezoelectric grain interactions, and thus demonstrate that superior lead-free piezoelectric microstructures can be fabricated by engineering its associated crystallographic and polarization texture. Computer-generated material representations, based on the experimentally determined microstructures, were used to simulate the crystallographic orientation of each grain, as function a macroscopic polarization and crystallographic texture. Computer-generated material representations, based on the experimentally determined microstructures, were used to simulate the crystallographic orientation of each grain, as function a macroscopic polarization and crystallographic texture. The method takes advantage of the anisotropy of the properties of the underlying single-crystal phases and delivers a guide to search for material anisotropy |microstructure parameters that are optimal in piezoelectric performance and reliability, and thus establish practical links between structure and macroscopic length scales.     

Life cycle assessment and cost analysis of very large‐scale PV systems and suitable locations in the world

Although the Sahara region has a high potential for solar power plants, the amount of installed photovoltaic (PV) system remains relatively low. This paper aims to evaluate these potentials of PV system installation in terms of environmental and economic viewpoints with indices of cost, energy, and greenhouse gas (GHG) emission. Two 1‐GW very large‐scale PV systems are simulated at Ouarzazate in Morocco and at Carpentras in France. The evaluation was performed using life cycle assessment. The lowest energy consumption and GHG emission are obtained while assuming cadmium telluride module. The result of our simulation shows that energy payback time is 0.9 years and CO₂ emission rate is 27.4 g‐CO_2‐eq/kWh in the Ouarzazate case. In cost estimation, generation costs are 0.06 USD/kWh in Ouarzazate and 0.09 USD/kWh in Carpentras in the case of 3% interest rate and 0.5 USD/W for multicrystalline silicon PV module price. In addition, by adapting 15% internal rate of return for 20% of budget, the generation costs become 0.09 USD/kWh in Ouarzazate and 0.13 USD/kWh in Carpentras under the same condition. Furthermore, the selection for suitable locations to install solar power plants in term of GHG emission is identified using geographical information system. Very high‐potential locations (lower than 38 g‐CO_2‐eq/kWh) could be obtained in North Chili, east and west Sahara, and Mexico. Copyright © 2015 John Wiley & Sons, Ltd.     

Permeability of ethanol solution through poly(lactic acid) film

The permeation properties of ethanol solution through poly(lactic acid) (PLA) films were investigated. The total flux of ethanol solution through PLA films was strongly depended on the flux of water. In addition, the diffusion coefficient of water was 1000 times higher than that of ethanol, and decreased with increasing feed concentration. After the permeation measurement, crystallization (X_C‐DSC = 1–2%) was observed. However, the crystallinity was not dependent on the feed concentration. On the other hand, the mole ratio of ethanol and water molecules in the PLA film strongly depended on the feed concentration. Based on the results, we concluded that the interaction with ethanol molecules caused the decrease in diffusion coefficient of water in PLA film. Thus, the permeation mechanism of the ethanol solution to the PLA film was investigated in detail. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42031.     

Reconnaissance report on geotechnical damage caused by a localized torrential downpour with emergency warning level in Kyushu,Japan

Kumamoto and Kogoshima prefectures are located in the southern Kyushu district of western Japan. In July 2020, a warm, humid air front triggered the delayed rains of the rainy season, resulting in torrential rains in many parts of Japan, especially in Kyushu. In particular, heavy downpours occurred in the southern Kyushu district on July 4th, causing severe damage to much of the infrastructure. Details could not be analyzed as usual because some branch office of local government were also damaged by floods. The spatial distribution of precipitation in the Kuma River basin, in the southern part of Kumamoto, was characterized by the uniformity of 400–500 mm on July 3rd and 4th. Finally, emergency warnings of torrential rain were issued for the southern Kumamoto and the northern Kagoshima Prefectures by Japan Meteorological Agency (JMA) at 4:50 a.m., July 4th, 2020. Then, the active rain front gradually shifted towards northern Kyushu. Again, torrential rain fell on northern Kyushu in the afternoon due to a stagnant rainy season front, and the JMA issued an emergency warning for a localized torrential downpour for parts of Fukuoka, Saga and Nagasaki prefectures at 4:30 pm. Gradually, the damage status involving geodisasters such as several types of slope failures, road subsidence, damage of the river levee was reported by local governments in each area where there had been emergency warnings.Based on the brief report of the pre-investigation team from the Kyushu branch of the Japan Geotechnical Society (JGS) in the first week after the disaster on July 4th, the geo-research teams investigated the following: 1) landslides; 2) damaged roads; 3) damaged river levees, and 4) any geotechnical infrastructures which were partially damaged and may be even more severely damaged by the next torrential rain. This reconnaissance report introduces the geological features in Kyushu, the analysis of precipitation distribution and geotechnical damages on the slope failures, road failures and river embankments based on reports obtained from July 4th to August 31st, 2020.     

Preparation of Highly Crystallized Strontium Titanate Powders at Room Temperature

Highly crystallized fine powder of strontium titanate (SrTiO₃) was obtained at room temperature simply by leaving a vial containing the powder mixture of Sr(OH)₂·8H₂O and hydrous titania gel (TiO₂·nH₂O) for 10 d. Solvent and additive(s) used in the conventional low‐temperature process were not used. The crystallinity judged from the FWHM of X‐ray diffraction peak was comparable to that obtained by a solid‐state reaction. To cause the reaction at room temperature, the titania gel had to contain a considerable amount of H₂O (n > 0.97). The reaction is considered to be neutralization of titanic acid [H₄TiO₄ or Ti(OH)₄] and strontium hydroxide (base). Using similar process, highly crystallized BaTiO₃ powder was also obtained at 60°C. In comparison with the formation temperature of BaTiO₃, tolerance factor in the perovskite structure was important for the room‐temperature synthesis of SrTiO₃. SrTiO₃ was hardly obtained at room temperature by the addition of saturated strontium hydroxide solution to the hydrous TiO₂ gel (n = 1.29). Therefore, the reaction seems to proceed in the hydrous titania gel. This process is characterized by three important points; “no solvent”, “no additional reagents”, and above all, “no heating”.     

Chemical Synthesis of Homogeneous Glycoproteins for the Study of Glycoprotein Quality Control System

The glycoprotein quality control system exists in the endoplasmic reticulum to maintain protein homeostasis and prevent accumulation of aberrant glycoproteins. Folding sensor enzyme uridine diphosphate (UDP) glucose : glycoprotein glucosyltransferase (UGGT) plays an important role in this system through its ability to discriminate immature or misfolded glycoproteins from native ones. UGGT transfers a glucose residue to a glycoprotein containing Man₉GlcNAc₂ (M9; Man=mannose, GlcNAc=N-acetyl-D -glucosamine) N-glycan only when the glycoprotein has not attained a native form. We chemically prepared homogeneous glycoproteins containing M9 N-glycan in the native form as well as in misfolded forms and examined them as substrates of UGGT. Glucose transfer to misfolded glycoproteins was clearly observed by LC-MS, but glycoproteins in the native form were barely glucosylated. Furthermore, we constructed an in vitro glycoprotein folding system in the presence of UGGT and found out that all folding intermediates which appeared during folding were also glucosylated. Through these experiments, we demonstrated the usefulness of chemically synthesized homogeneous glycoproteins as probes to gain insights into the molecular basis of the glycoprotein quality control system.     

Electrochemical measurement to examine influence of ions,DO, and pH on corrosion of early-generation conduits

ABSTRACT

In order to effectively implement measures against the adverse effects of large earthquakes on telecommunication conduits, it is important to elucidate which conduit is vulnerable. Telecommunication conduits consist of pipe bodies and joints, and as is well known the joints are weaker than the bodies against seismic loading. Hence, the seismic performance of the conduits depends on the performance of the joints. To maintain conduits properly, the corrosion rate of conduits' joint in the field must be determined. Several sites were selected and investigated for the amount of stagnant water in manholes. Next, the stagnant water test specimens were collected and observed for the extent of corrosion inside via a pipe camera, and subsequently analysed collected water test specimens. Moreover, the solution resistances and polarisation resistances using the AC impedance method and carbon steel coupons were measured. The experiments revealed differences between the measured values recorded at the different sites. It was also found that some data were related to corrosion on the inside of the conduits.

This paper is part of a supplementary issue from the 17th Asia-Pacific Corrosion Control Conference (APCCC-17).