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Bending fatigue strength of case-carburized helical gears (In the case of large helix angles)
Kengo Nojima,Kengo Ogata,Motomu Tanaka,Ryosuke Nishi,Yuichi Ono,Takao Koide 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.12
Case-carburizing enlarges the depth of the hardened layer at the tooth width end on the acute angle side of helical gears. For the helical gears with large helix angles (Exceeding 25°), this hardened layer may lower their bending fatigue strength. Therefore, we investigated the influence of this hardened layer on their bending fatigue strength through the bending fatigue tests. Our results suggest that this hardened layer might reduce the case-carburizing’s effect to enhance their bending fatigue strength. Thus, using only the maximum tooth root stress would be inadequate for evaluating their bending fatigue strength, and it would be necessary to consider the relationship between the hardened layer and the tooth root stress distribution (Especially, the stress applied at the tooth width end on the acute angle side) from the beginning of meshing to the end.
도시녹지의 미기후개선, $CO_2$흡수 및 화재방지의 효과
조현길,Yoshiteru Nojima 한국자원식물학회 2000 한국자원식물학회지 Vol.13 No.3
본 연구는 한국과 일본의 특정 도시내 주거녹지의 미기후개선 및 $CO_2$ 농도저감 효과를 계량화하였다. 또한, 도시수목에 의한 화재방지의 효과를 검토하고, 그들 효과를 함께 증진하기 위한 녹지계획 및 관리 전략을 제시하였다. 수목 생장기간 중 평균 온도는 수목피도 12% 및 22%인 지구에서 녹지부재의 지구보다 각각 0.5$^{\circ}C$, 1.2$^{\circ}C$ 더 낮았다. 수목의 호당 연간 $CO_2$, 흡수량과 $O_2$, 생산량은 수목피도가 2배 더 높은 지구에서 3배 더 많았다. 수목피도 22% 지구의 수목은 광합성과 에너지 절약을 통해 지구 총 $CO_2$배출량의 약 3%를 해마다 상쇄시켰고, 지구내 거주민 모두가 연간 필요로 하는 산소량의 약 10%를 생산하는 중요한 역할을 담당하였다. 흉고직경 15cm인 느티나무 한 그루의 8월 하루 증산량은 7,100kca1/h(사무실 24평용) 냉방능력을 가진 냉방기를 12시간 동안 약 3대 가동하는 효과와 같았다. 또한, 그 수목은 해마다 32리터의 휘발유 소비에 따른 $CO_2$, 배출량을 상쇄시켰고, 한 사람이 68일간 호흡하는데 필요한 산소량을 생산하였다. 화재 방지를 비롯한 미기후개선 및 $CO_2$ 농도저감의 효과를 증진하기 위해, 수종선정 , 건물주변 식재기법, 녹지확충, 식생관리 등과 관련된 도시 주거녹지의 적정한 계획 및 관리전략을 제시하였다. 제안한 전략은 현존 단독주거지에서는 물론 새로운 주거단지를 조성하는데 유용하게 적용될 수 있을 것으로 기대한다. This study quantified the effects of urban greenspace on microclimate amelioration and atmospheric $CO_2$ reduction for several residential districts selected in Korea and Japan. The study also explored fire obstruction by urban trees to develop systematic planting guidelines. Transpiration by a Zelkova serrata tree (diameter at breast height: 15 cm) in a day of August equaled cooling effect of about 3 air conditioners running for 12 hours. Average air temperature for the growing season was 0.5$^{\circ}C$ and 1.2$^{\circ}C$ cooler, respectively, in districts with 12% and 22% cover of woody plants than in a district with no vegetation. Annual $CO_2$ uptake and $O_2$ production by woody plants were 3 times greater in a district which was 2 times higher in their cover. Woody plants played, in a district with their 22% cover, an important role through offsetting total $CO_2$ emission from the district by about 3% annually, and through producing 10% of annual $O_2$ requirement by all residents within the district. Appropriate planning strategies of residential greenspace, including species selection, planting layout, greenspace enlargement, and maintenance were suggested to improve microclimate amelioration, air purification, and fire obstruction.
Nitta, Junichi,Nojima, Masanori,Ohnishi, Hirofumi,Mori, Mitsuru,Wakai, Kenji,Suzuki, Sadao,Fujino, Yoshihisa,Lin, Yingsong,Tamakoshi, Koji,Tamakoshi, Akiko Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.3
Background: We investigated four factors, height, weight gain since age 20, physical activity, and alcohol drinking, for associations with risk of breast cancer (BC) according to menopausal status, using the latest data of the Japan Collaborative Cohort Study (JACC Study). Materials and Methods: We confined the analysis to 24 areas available of cancer incidence information, excluding women with a previous diagnosis of BC. Baseline data were collected from 38,610 (9,367 premenopausal, and 29,243 postmenopausal) women during 1988 and 1990. The study subjects were followed-up at the end of 2009, and 273 (84 premenopausal, and 189 postmenopausal) cases of BC were newly diagnosed in 501,907 person-years. The Cox model was used to estimate a hazards ratio (HR) and its 95% confidence interval (CI) of BC risk. Results: As a result of the multivariate analysis adjusting for age at baseline survey, age at menarche, number of live births, and, age at first delivery, weight gain since age 20 of 6.7 kg-9.9 kg, and ${\geq}10.0kg$ were significantly associated with increased risk for postmenopausal BC (HR=2.48, 95% CI 1.40-4.41, and, HR=2.94, 95% CI 1.84-4.70, respectively). Significantly increased trend of BC risk was also observed in weight gain since age 20 (p for trend, p<0.001). Amount of ethanol intake per day${\geq}15.0g$ was significantly associated with increased risk for postmenopausal BC in the multivariable-adjusted analysis (HR=2.74, 95% CI 1.32-5.70). Conclusions: Higher weight gain in adulthood and larger amounts of ethanol intake were significantly associated with increased risk of BC in Japanese postmenopausal women. None of the investigated factors were significantly associated with BC risk in Japanese premenopausal women.
Chotoku, M.,Nojima, T.,Ochiai, A.,Aoki, H.,Lee, H.G.,Lee, S.I. North-Holland 2009 Physica. C, Superconductivity Vol.469 No.15
We have performed the detailed measurements of temperature dependence of magnetization M(T) on MgB<SUB>2</SUB> single crystals in a wide range of field H using torque magnetometry. In a field region, where the peak effect in M(H) is observed, we find that M(T) of the warming branch increases monotonously with T and exhibits a small step-like increase at T<SUB>1</SUB><SUP>*</SUP>, which is related to the order-disorder transition, while M(T) of the cooling branch, showing the larger values than that in warming branch below T<SUB>1</SUB><SUP>*</SUP>, drops suddenly toward the warming branch at T<SUB>2</SUB><SUP>*</SUP>. We ascribe this anomalous behavior of M(T) of the cooling branch to a supercooling phenomenon of disordered phase, which transforms to the ordered state at T<SUB>2</SUB><SUP>*</SUP>.