Melt-quenched oxide glasses with ultrahigh Young's modulus and small thermal expansion coefficient

The well-known Makishima–Mackenzie relationship, consisting of two terms of the dense packing structure and dissociation energy regarding bonding in constituent oxides, enables fabricating oxide glasses with ultrahigh Young's modulus (∼140 GPa) and a small coefficient of thermal expansion (CTE) (∼4 ppm/K). The effects of increasing MgO and Ta₂O₅ contents in an MgO–Ta₂O₅–Al₂O₃–SiO₂–B₂O₃ glass system using a conventional melt-quenching method are revealed. The essential oxides of Al₂O₃ and Ta₂O₅ are primarily suitable for dense packing structures dominated by a large coordination number of oxygens. The substitution of CaO by MgO results in high dissociation energy when the glass composition falls in the peraluminous regime (Al₂O₃/[MgO + CaO] > 1). A small CTE is realized by increasing the molar ratio of Al₂O₃/MgO. According to magic-angle spinning-nuclear magnetic resonance spectra, mechanically and thermally functional oxide glasses depend on their structures. These findings facilitate the development of glass substrate applications without thermal dilatation.     

Size-Controlled Synthesis of Luminescent Few-Atom Silver Clusters via Electron Transfer in Isostructural Redox-Active Porous Ionic Crystals (Small 23/2023)

Ag clusters with a controlled number of atoms have received significant interest because they show size-dependent catalytic, optical, electronic, or magnetic properties. However, the synthesis of size-controlled, ligand-free, and air-stable Ag clusters with high yields has not been well-established. Herein, it is shown that isostructural porous ionic crystals (PICs) with redox-active polyoxometalates (POMs) can be used to synthesize Ag clusters via electron transfer from POMs to Ag⁺. Ag clusters with average numbers of three, four, or six atoms emitting blue, green, or red colors, respectively, are formed and stabilized in the PICs under ambient conditions without any protecting ligands. The cluster size solely correlates with the degree of electron transfer, which is controlled by the reduction time and types of ions or elements of the PICs. Thus, advantages have been taken of POMs as electron sources and PICs as scaffolds to demonstrate a convenient method to obtain few-atom Ag clusters.     

Detection of abnormal fish by image recognition using fine-tuning

Artificial Life and Robotics - Fishermen need to remove abnormal or dead fish for the prevention of viral infection. However, the identification of diseased fish is more ambiguous that the...     

Hydrogen production using thermochemical water-splitting Iodine–Sulfur process test facility made of industrial structural materials: Engineering solutions to prevent iodine precipitation

A thermochemical water-splitting iodine–sulfur process offers the potential for mass-producing hydrogen at high-efficiency levels, and it uses high-temperature heat sources, including high-temperature gas-cooled reactors, solar heat, and waste heat of industries. The raw material (H₂O) is split into H₂ and O₂ by combining three chemical reactions using sulfur and iodine. Currently, R&D tasks are essential to confirm the integrity of the components that are made of practical structural materials and the stability of hydrogen production in harsh working conditions. A test facility for producing hydrogen was constructed from corrosion-resistant components that are developed using industrial materials. In addition, for stable hydrogen production, technical issues for instrumental improvements (i.e., stable pumping of the hydrogen iodide (HI)–I₂–H₂O solution without locking the shaft seal, prevention of leakage by improving the quality control of glass-lined steel, prevention of I₂ precipitation using a water removal technique in a Bunsen reactor) were solved. The entire process was successfully operated for 150 h at the rate of ca. 30 L/h. The integrity of components made of practical structural materials and the operational stability of the hydrogen production facility in harsh working conditions were demonstrated.     

The Influence of Pre-treatment on the Properties of Photographic Gelatin

Abstract

The influence of the liming period in the manufacturing process on the chemical and photographic properties of gelatin was investigated. Three limed osseins soaked for various periods were prepared and gelatins zvere extracted from them. The impurity contents of the gelatins and the physical restraining properties decreased with prolonging liming periods. The impurity contents and physical retardance were also relative to the extraction order. The deionization treatment of gelatin decreased the impurity contents and the differences of restraining effect with extraction order. Furthermore, the fractionation of sample gelatins by use of gel permeation chromatography was applied to study the relationship to the molecular weight of impurity contents and amino acid composition, as affected by the liming period.     

Soft Decision with Soft Target for Car-like Mobile Vehicle in Dynamic Environment

Online flexible operation of a car-like mobile vehicle with non-holonomic constraints in dynamic environment is still a very challenging problem because the surrounding situations are not qualified in static, knowledge is only partial and the execution is often associated with uncertainty. The difficulty lies in the setting of appropriate moving sub-targets in real-time to obtain a collision-free and low-cost path. In this paper, we present a new approach for the autonomous motion control of mobile vehicle in a narrow area with static and dynamic obstacles. It is based on the selection of sub-target points of vehicle's movement called ‘soft target’ which is a target set defined as all possible and reachable via-points in a navigation space. The soft target is acquired by online learning based on the final target and environment information. Each element of it has its membership value in [0, 1] denoting its evaluation degree. With the acquired soft target, soft decision is made like human's decision process by predictive fuzzy control (PFC) to achieve final target safely and economically. The simulation results show the effectiveness and flexibility of the proposed vehicle motion control method. © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

New Sweet Potato Line having low Gelatinization Temperature and altered Starch Structure

A new sweet potato breeding line, Kanto 116, was developed, featuring low gelatinization temperature and an altered starch fine structure. Starch granules from Kanto 116 showed an abnormal morphology characterized by cracking into granules. Starch content, amylose content and tuberous root appearance of Kanto 116 were similar to those of the control and the parents. Pasting temperatures of Kanto 116 starch determined by the Rapid Visco Analyser were 51.4 — 52.6 °C, approximately 20 °C lower than those of the control and parents starches. Onset, peak, and conclusion temperature of gelatinization, and gelatinization enthalpy of Kanto 116 starch determined by differential scanning calorimetry were 39.0 °C, 46.9 °C, 64.8 °C, and 8.8 J/g, respectively, and much lower than those of the control and parents starches. The chain‐length distribution of the amylopectin molecules, determined by high‐performance anion‐exchange chromatography, showed that Kanto 116 starch had a higher proportion of short chains (DP 6 — 11) and a lower proportion of chains between DP 12 — 28 than control and parent starches. The debranched β‐limit dextrin of Kanto 116 starch also showed that the proportion of both short and long B1 chains was different from those of the control and parents starches.