關西電力公司

Existing spillway piers constructed more than 60 years ago in Japan are usually reinforced with round rebars and have very low rebar ratios; consequently, their seismic response may be strongly influenced by post-cracking bond–slip. However, the applicability of nonlinear analytical models to such piers has not yet been systematically clarified. In this study, practical modeling strategies for existing spillway piers were investigated by performing Incremental Dynamic Analysis (IDA) using both a beam model based on nonlinear moment–curvature (M-φ) relationships and a 3D finite element analysis that explicitly accounts for bond–slip between concrete and rebar. An actual spillway pier was analyzed at multiple seismic intensity levels, and the effects of bar diameter, rebar ratio, and bond condition were examined via 3D finite element analysis. The results showed that the beam model is useful for global screening but may misclassify the damage mode because it cannot explicitly represent bond–slip. By contrast, the 3D finite element analysis reproduced flexure-dominant damage patterns and quantified the influence of bond–slip on maximum displacement, residual displacement, rebar strain, tensile damage distribution, and compression damage distribution. These differences became more pronounced under stronger ground motions and for larger bar diameters and lower rebar ratios. The findings support a staged strategy for seismic performance evaluation that combines beam models for global screening with 3D finite element analysis for detailed member-level assessment.

Abstract Background Hypertension is an important occupational risk factor for adults and associated with the working type and working hours. Objective We aimed to determine the association between overtime work hours per month (OWHs) and the risk of developing occupational hypertension. Subjects and methods We studied 1504 employees of two public institutions, who were providing electricity service to the general population on Kansai area in Japan. The age ranged from 23 to 62 years (mean 39.8±4.0 ) and 86.4 % of the cohort were men. OWHs were calculated from the attendance management system. OWHS were grouped into the following categories; less than 50 hours, 50 to 69 hours, more than 70 hours per month. Subjects were analyzed by body mass index, blood pressure, blood chemistry, and sleeping times according to annual health check-up data. And, workplace clinic blood pressure was taken at rest during the Industrial physician interview due to overtime work. Diagnosis of hypertension was based on systolic blood pressure (SBP) ≧140 and/or diastolic blood pressure (DBP) ≧90mmHg, according to the Janese Society of Hypertension guidelines. Results The mean value of OWTs in this study subjects were 44.4±11.6 hours. The mean value of SBP and DBP at workplace clinic of subjects with more than 50 hours OWHs, were significantly elevated to subjects with less than 50 hours OWHs (126±15.1 mmHg vs 114.8±12.6 mmHg; p<0.0001 and 80.5±12.1mmHg vs 71.8±9.9mmHg; p<0.0001, respectively. HR:1.64, 65%CI: 1.02-2.53). The mean value of SBP at workplace clinic of subjects with more than 70 hours OWHs were more elevated compared to subjects with 50 to 69 hours OWHs (132.4±13.5 mmHg vs 122.9±14.9 mmHg; p<0.0014, HR: 1.42, 95%CI: 1.14-2.01). Among employees aged less than 35years, there were no significant differences of both SBP and DBP under more than 50 hours OWHs (114.8±12.6 mmHg vs 115.1±10.0 mmHg; p=ns).The mean values of SBP and DBP at annual health check-up have not significantly differentiated between subjects with less than 50 hours and more than 50 hours OWHs (114.8 ±12.6 mmHg vs 114.9±13.3 mmHg; p=ns and 7.9±10.2 mmHg vs 71.9±10.2mmHg; p=ns, respectively). Conclusion Long OWHs were an important risk factor of occupational hypertension among employees aged more than 35 years, which could not be detected at annual health check-up. Workplace strategies targeting long OWHs could be effective in reducing the clinical health burden of occupational hypertension.

Renewable-electricity-powered hydrogen supply chains require compact, efficient, and demand-responsive NH3 crackers. Here we develop a microwave-driven ammonia decomposition system based on an LTA-type zeolite catalyst loaded with 10 wt% Ru nanoparticles that directly converts electrical energy into chemical energy through localized catalyst heating. The system achieves an external energy conversion efficiency of 48%, based on the net microwave input power after subtracting the reflected power. Thermal simulations further reveal an internal energy conversion efficiency of 60%, based on the microwave energy absorbed by the catalyst, independent of microwave frequency, corresponding to a hydrogen production efficiency of 92% on a lower heating value (LHV) basis. The reactor maintains high reaction rates while keeping the reactor wall at only 450 °C, enabling the use of conventional stainless steels. Multiphysics simulations combined with in situ synchrotron total scattering reveal that the dielectric properties of the zeolite support promote efficient power-to-chemical energy conversion by localizing electromagnetic energy within the catalyst. Fast start-up, rapid shutdown, and stable operation under fluctuating power demonstrate a compact and demand-responsive platform for decentralized hydrogen production compatible with renewable electricity.