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A self-calibration scheme for two-dimensional free-form probing measurement under the assumption of rigid-body machine kinematic model
No full textA major uncertainty contributor to the on-machine probing is linear axis kinematic errors. This paper proposes a novel self-calibration scheme to separate the workpiece geometry and machine tool kinematic errors from the probed profiles. Many self-calibration schemes have been well developed, but they are limited to either of the straightness, roundness, and two-dimensional (2D) grid point positions, since they require the probed points being in a closed set, as the workpiece is rotated or translated. This paper proposes its extension to a free-form 2D geometry. A key idea is on the assumption that the machine tool’s positioning error is in accordance with the rigid-body kinematic model. It makes linear axis error motions, represented in a look-up table format, be in a closed set. Two experimental case studies are presented. The uncertainty assessment is essential to investigate the effectiveness of the proposed scheme for the given workpiece geometry
Porosity Engineering of Pt-Loaded Nb-SnO2 Catalyst Layers in Polymer Electrolyte Fuel Cells
No full textRecently, the emphasis on hydrogen-fuel utilization technologies─particularly polymer–electrolyte fuel cells (PEFCs)─has recently shifted from light-duty to heavy-duty vehicles. There is consequently an urgent need to develop a catalyst with excellent durability. In this study, we have endeavored to improve the power-generating performance of PEFCs by using high-durability Nb–SnO2 (NTO) nanoparticles and by controlling the porosity of the catalyst layer. We tuned the fused-aggregate network structure of the NTO nanoparticles by annealing them at 1000 or 1200 °C. This treatment promoted the development of aggregated structures of the NTO nanoparticles, which resulted in an increase in the porosity of the catalyst layer. In these catalysts, the maximum current density increased with increasing porosity. The gas-diffusion resistance calculated from the current–voltage (I–V) characteristics decreased from 148 m/s for NTO nanoparticles before annealing, to 113 m/s after annealing at 1000 °C, and to 102 m/s after annealing at 1200 °C. This study thus demonstrates that high-performance catalysts with high durability for PEFCs can be achieved by precisely engineering the porosity of the catalyst layer.This work was supported by JSPS KAKENHI grant numbers JP22K20482, JP23K13590 (T.H.), and JP23H01745 (T.O.). This work was partly supported by the Center for Functional Nano Oxides at Hiroshima University, the International Network on Polyoxometalate Science, the JSPS Core-to-Core Program, the Information Center of Particle Technology, Japan, and the Hosokawa Powder Technology Foundatio
Material interface modeling by the enriched RKPM with stabilized nodal integration
No full textIn this paper, an enriched reproducing kernel particle method combined with stabilized conforming nodal integration (SCNI) is proposed to tackle material interface problems. Regarding the domain integration, the use of SCNI offers an effective NI technique and eliminates the zero-energy modes which occurs to direct NI. To model material interfaces, the method enriches the approximation by adding special functions constructed based on the level set function to represent weak discontinuities. Numerical examples with simple and complicated geometries of interface problems in two-dimensional linear elasticity are presented to test the performance of the proposed method, and results show that it considerably reduces strain oscillations and yields optimal convergence rates.Huy Anh Nguyen is gratefully acknowledged the support of this work by Japanese Government (MEXT) scholarship for his Doctoral Program
Role of cell proliferation in strobilation of moon jellyfish Aurelia coerulea
No full textThe life cycle of the moon jellyfish Aurelia coerulea consists of sessile polyp and free-swimming jellyfish stages. Strobilation is a polyp-to-jellyfish transition comprising sequential segment formation (segmentation), subsequent morphogenesis into ephyrae (young jellyfish), and detachment of the ephyrae. Cell proliferation is involved in metamorphosis in various animals. In the present study, we examined the relationship between cell proliferation and strobilation in A. coerulea. To visualize cell proliferation at various stages of strobilation, 5-bromo-2′-deoxyuridine labeling experiments were conducted, in which cell proliferation was distributed in the segments and prospective regions of the next segment during segmentation. Cell proliferation in segments continues during ephyra morphogenesis. Hydroxyurea, a cell-cycle inhibitor, was administered to investigate cell proliferation in animals at different stages of strobilation. In this study, hydroxyurea interrupted the initiation of strobilation, segmentation, and ephyra morphogenesis, but not ephyra detachment. This suggests that cell proliferation plays a crucial role in generating a new segment and constructing the ephyra body
Stimulation of nuclear receptor REV-ERBs alleviates monosodium iodoacetate-induced osteoarthritis pathology of mice and the induction of inflammatory molecules expression in primary cultured chondrocytes
No full textBecause inflammation in chondrocytes contributes to the induction of osteoarthritis (OA), regulation of their activity is essential. A previous study showed that stimulation of the reverse erythroblastosis virus (REV-ERB) nuclear receptors in spinal glial cells elicits anti-inflammatory and antinociception effects in animal models of chronic pain. However, the involvement of REV-ERBs in chondrocyte functions and OA pathologies remains to be elucidated. In the current study, we found that pretreatment with the REV-ERB agonist SR9009 significantly blocked the increases in inflammatory molecules [(matrix metalloproteinase (MMP) 3, MMP9, and MMP13] and cytokines (interleukin-1β and tumor necrosis factor) in primary cultured chondrocytes following treatment with lipopolysaccharide. Furthermore, repeated intra-articular treatment with SR9009 significantly prevented monosodium iodoacetate-induced mechanical hypersensitivity and tended to partially reduce knee joint damage in mice. In conclusion, our findings suggest that REV-ERBs have a critical role in alleviating nociceptive hypersensitivity in OA pathologies by negatively regulating inflammation in chondrocytes.This work was supported by grants from the Takeda Science Foundation, Suzuken Memorial Foundation, Uehara Memorial Foundation, and Nakatomi Foundation
Development of a large-bore plasma window with an indirectly heated hollow cathode
No full textFor plasma window (PW) applications, we developed the cascade arc discharge device with an indirectly heated hollow cathode. The 8-mm channel diameter hollow cathode made of a lanthanum hexaboride (LaB ) was heated by the C/C composite heater surrounding the cathode to increase the thermionic electron emission. The PW developed successfully separated 2.4 kPa and 16 Pa, and the pressure separation capability was sustained for over 1 h. H- Stark broadening measurement and the Thomson scattering measurement showed that the electron density and temperature inside the channel reached 1019-1020m-3 and 2.0 eV, respectively. The power balance analysis on the electron thermal energy revealed that the neutral density and temperature inside the channel were as high as 1023 m-3 and 4000 K, respectively. The relation between the pressure separation capability and the neutral temperature showed that the flow inside the channel of the PW had the molecular flow feature. The SEM-EDX analysis on the LaB cathode showed that boron diffused to the molybdenum (Mo) shaft during plasma operation, which supported the LaB cathode. Mo shaft became brittle after more than 50 h of operation, exhibiting the necessity of buffer material between the LaB cathode and Mo shaft for long-duration operation.This research was supported by JSPS KAKENHI under Grant No. JP20H00141, O. S. G. Fund, Furukawa Research Fund, and NIFS Collaboration Research Program under Grant Nos. NIFS NIFS22KIIH003, NIFS22KIIH011, and NIFS23KIIH016
英語文学作品の原文とそのリトールド版との比較に基づいた英語教材開発 : エミリー・ブロンテ作『嵐が丘』の場合
No full textThe aim of this paper is to develop teaching materials based on Wuthering Heights by Emily Brontë. The materials are targeted at university EFL learners. There are at least two problems to be solved: (1) the target learners might have difficulty understanding the literal meaning of the original text; (2) even if they literally understand the text, it might be hard for them to interpret it. To solve the second problem, the developed teaching materials show an interpretation based on Van Ghent (1953), which is usually categorized as New Criticism and, as such, is relatively easier to understand than interpretations based on other literary theories like New Historicism or Post Colonialism. Five passages, which were judged as important for the interpretation, were chosen from the original text with corresponding five passages from Pearson English Readers (2008). The retold text helps learners grasp the literal meaning of the original one. The developed teaching materials also contain 16 questions which, though answerable with literal understanding of the text, are deeply related to the interpretation presented
青年期における家庭展望の概念と研究方法の検討 : ライフキャリア理論からのアプローチ
No full textThe purpose of this study was to examine the concepts, influencing factors, and research methods related to adolescents’ perspectives on their future families through a review of previous research on their views of the future and to understand their life plans. One’s outlook for the future is expressed by the concept of “time perspectives,” and another purpose of this study was to clarify the state of adolescents’ time perspectives and the factors that influence them. These, in turn, can be used to provide suggestions for educational support that promotes the development of time perspectives. A review of the research shows that there are still many issues to be addressed. For instance, we need to understand adolescents’ time perspectives in greater detail by classifying them by focusing on plans for their future occupations, families, and other areas of life. In particular, since there is no previous research focused on the time perspectives of adolescents’ family lives, there is a need to develop objective indicators to capture and classify these and to examine the factors related to them. The results of this study suggested the need to consider what kinds of career education are effective and necessary in secondary and higher education
