Lattice distortion in selective laser melting (SLM)-manufactured unstable β-type Ti-15Mo-5Zr-3Al alloy analyzed by high-precision X-ray diffractometry

A peculiar lattice distortion in a selective laser melting (SLM)-manufactured unstable β-type Ti-15Mo-5Zr-3Al was observed for the first time, through high-precision X-ray diffraction (XRD) analyses. After SLM, Ti-15Mo-5Zr-3Al exhibited a body-centered-tetragonal structure instead of a body-centered-cubic structure; the c-axis was 0.63% shorter than the a-axis. The XRD analyses also revealed tensile residual stresses of 210 ± 12 MPa at the specimen surface. A numerical simulation indicated rapid cooling during the SLM, which could have caused the residual stresses. A comparison of the partially stress-released SLM specimen and an electron beam melting-manufactured specimen with negligible residual stress suggested that the residual stress caused by the rapid cooling in SLM induced the lattice distortion. This finding is not consistent with the previous understanding that residual stress changes the lattice parameter without lattice distortion. This study provides new insight into lattice distortion generated by a combination of SLM-specific ultrarapid cooling and unstable phases.Takase A., Ishimoto T., Suganuma R., et al. Lattice distortion in selective laser melting (SLM)-manufactured unstable β-type Ti-15Mo-5Zr-3Al alloy analyzed by high-precision X-ray diffractometry. Scripta Materialia, 201, 113953. https://doi.org/10.1016/j.scriptamat.2021.113953

Surface residual stress and phase stability in unstable β-type Ti–15Mo–5Zr–3Al alloy manufactured by laser and electron beam powder bed fusion technologies

The differences between the physicochemical properties of the laser and electron beam powder bed fusion (L- and EB-PBF) methods are yet to be explored further. In particular, the differences in the residual stress and phase stability of alloys with unstable phases remain unexplored. The present work is the first to systematically investigate how the heat source type and process parameters affect the surface residual stress and phase stability of an unstable β-type titanium alloy, Ti–15Mo–5Zr–3Al. The surface residual stress and β-phase behavior were studied using high-precision X-ray diffraction (HP-XRD). Significant differences were observed between the two methods. The L-PBF-made specimens exhibited tensile residual stresses of up to 400 MPa in the surface area. HP-XRD analysis revealed a stress-induced lattice distortion, interpreted as a transitional state between the β-phase and α”-phase. In contrast, the EB-PBF-made specimens showed no significant residual stress and had an undistorted β-phase coexisting with the hexagonal α-phase caused by elemental partitioning. This study provides new insights into the previously neglected effects of L-PBF and EB-PBF in unstable β-type titanium alloys.Takase A., Ishimoto T., Suganuma R., et al. Surface residual stress and phase stability in unstable β-type Ti–15Mo–5Zr–3Al alloy manufactured by laser and electron beam powder bed fusion technologies. Additive Manufacturing, 47, 102257. https://doi.org/10.1016/j.addma.2021.102257

Evaluation of Fiber Crops as Adsorption Materials for Cesium and Strontium Ions

After the accident of atomic power plants in Fukushima, Japan, the removal of radioactive materials released to environment is most important task and rapid response to the severe problem is required. It is well known that various biomass have adsorption ability for toxic metal ions from aqueous media. We have evaluated the adsorption ability of many fiber crops for cesium and strontium ions. As the results, several fiber crops have considerable ability for the adsorption of such metal ions and are useful for a water and soil purification system in large scale

Comparison of phase characteristics and residual stresses in ti-6al-4v alloy manufactured by laser powder bed fusion (L-pbf) and electron beam powder bed fusion (eb-pbf) techniques

Ti-6Al-4V alloy fabricated by laser powder bed fusion (L-PBF) and electron beam powder bed fusion (EB-PBF) techniques have been studied for applications ranging from medicine to aviation. The fabrication technique is often selected based on the part size and fabrication speed, while less attention is paid to the differences in the physicochemical properties. Especially, the relationship between the evolution of α, α’, and β phases in as-grown parts and the fabrication techniques is unclear. This work systematically and quantitatively investigates how L-PBF and EB-PBF and their process parameters affect the phase evolution of Ti-6Al-4V and residual stresses in the final parts. This is the first report demonstrating the correlations among measured parameters, indicating the lattice strain reduces, and c/a increases, shifting from an α’ to α+β or α structure as the crystallite size of the α or α’ phase increases. The experimental results combined with heat-transfer simulation indicate the cooling rate near the β transus temperature dictates the resulting phase characteristics, whereas the residual stress depends on the cooling rate immediately below the solidification temperature. This study provides new insights into the previously unknown differences in the α, α’, and β phase evolution between L-PBF and EB-PBF and their process parameters.Takase A., Ishimoto T., Morita N., et al. Comparison of phase characteristics and residual stresses in ti-6al-4v alloy manufactured by laser powder bed fusion (L-pbf) and electron beam powder bed fusion (eb-pbf) techniques. Crystals, 11, 7, 796. https://doi.org/10.3390/cryst11070796

Speech corpora in NINJAL, Japan demonstration of corpus concordance systems : Chunagon and Kotonoha

National Institute for Japanese Language and LinguisticsNational Institute for Japanese Language and LinguisticsNational Institute for Japanese Language and LinguisticsNational Institute for Japanese Language and LinguisticsNational Institute for Japanese Language and LinguisticsNational Institute for Japanese Language and LinguisticsNational Institute for Japanese Language and LinguisticsNational Institute for Japanese Language and LinguisticsNational Institute for Japanese Language and LinguisticsNational Institute for Japanese Language and LinguisticsNational Institute for Japanese Language and LinguisticsThe National Institute for Japanese Language and Linguistics, Japan (NINJAL, Japan) provides a demonstration site in the LPSS 2019 conference. This manuscript presents an overview of the demonstration of three corpora: Corpus of Spontaneous Japanese, Corpus of Everyday Japanese Conversation, and Corpus of Japanese Dialects.NINJAL also demonstrates two concordance systems. The first is "Chunagon (中納言)" which is a morpheme based concordance system that was made publicly available in 2011. The second is the currently developing system "Kotonoha" released in 2018 that enables query of multiple corpora in terms of register type and period

Site-directed mutagenesis by biolistic transformation efficiently generates inheritable mutations in a targeted locus in soybean somatic embryos and transgene-free descendants in the T-1 generation

The clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated endonuclease 9 (Cas9) system is being rapidly developed for mutagenesis in higher plants. Ideally, foreign DNA introduced by this system is removed in the breeding of edible crops and vegetables. Here, we report an efficient generation of Cas9-free mutants lacking an allergenic gene, Gly m Bd 30K, using biolistic transformation and the CRISPR/Cas9 system. Five transgenic embryo lines were selected on the basis of hygromycin resistance. Cleaved amplified polymorphic sequence analysis detected only two different mutations in e all of the lines. These results indicate that mutations were induced in the target gene immediately after the delivery of the exogenous gene into the embryo cells. Soybean plantlets (T-0 plants) were regenerated from two of the transgenic embryo lines. The segregation pattern of the Cas9 gene in the T-1 generation, which included Cas9-free plants, revealed that a single copy number of transgene was integrated in both lines. Immunoblot analysis demonstrated that no Gly m Bd 30K protein accumulated in the Cas9-free plants. Gene expression analysis indicated that nonsense mRNA decay might have occurred in mature mutant seeds. Due to the efficient induction of inheritable mutations and the low integrated transgene copy number in the T-0 plants, we could remove foreign DNA easily by genetic segregation in the T-1 generation. Our results demonstrate that biolistic transformation of soybean embryos is useful for CRISPR/Cas9-mediated site-directed mutagenesis of soybean for human consumption