DETERMINATION OF ZINC IN VEHICLE EXHAUST PARTICULATES BY INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION SPECTROMETRY WITH ELECTROTHERMAL VAPORIZATION

Joint Research on Environmental Science and Technology for the Eart

Design of Titanium Alloys Insensitive to Thermal History for Additive Manufacturing

Powder bed fusion is the most common technology used for 3D printing, where thermal energy is used to selectively melt/sinter granular materials into solid shapes. The build platform is then lowered, more powder is added, and the process is repeated for the next layer to fully print the design. As a result, the built-up part is repeatedly heated. Therefore, materials that are not sensitive to thermal history are preferred for this process. The Ti–Zr system forms a continuous solid solution for both β- and α-phases. The presence of Fe in Ti alloys is inevitable; however, it provides some beneficial effects. The purpose of this work was to prepare Ti–Zr–Fe alloys and investigate their heat treatment behaviour. Ti-xmass%Zr-1mass%Fe alloys (x = 0, 5, 10) were prepared with arc melting. The formation of a solid solution of Zr in Ti was confirmed on the basis of X-ray diffraction peak shifts and hardening effects. A small amount of β-phase precipitation was suggested by the change in electrical resistivity after isothermal ageing at 673 and 773 K. However, no obvious phase or microstructural changes were observed. The laser scanning increased the volume of the precipitates and also coarsened them, but the effect was limited.Ueda M., Ting Hsuan C., Ikeda M., et al. Design of Titanium Alloys Insensitive to Thermal History for Additive Manufacturing. Crystals 13, 568 (2023); https://doi.org/10.3390/cryst13040568

Aflatoxins in Rice Artificially Contaminated with Aflatoxin-producing Aspergillus flavus under Natural Storage in Japan

Aflatoxin (AFT) contamination is frequent in foods grown in tropical regions, including rice. Although AFTs are generally not found in temperate-region foods, global warming has affected typical temperate-region climates, potentially permitting the contamination of foods with AFT-producing Aspergillus flavus (A. flavus). Here we investigated the AFT production in rice during storage under natural climate conditions in Japan. We examined AFTs in brown rice and rough rice artificially contaminated with A. flavus for 1 year in Japan, and we subjected AFTs in white rice to the same treatment in airtight containers and examined the samples in warm and cold seasons, simulating the storage of white rice in general households. In the brown rice, AFTs increased after 2 months (March) and peaked after 9 months (October). The AFT contamination in the rough rice was minimal. After the polishing and cooking of the brown rice, AFTs were undetectable. In the white rice stored in airtight containers, AFTs increased after 1 month (August) and peaked after 2 months (September). Minimal AFTs were detected in the cold season. Thus, AFT contamination in rice may occur in temperate regions following A. flavus contamination. The storage of rice as rough rice could provide be useful for avoiding AFT contamination

β型チタン合金の比熱的ω相に関する研究

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