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An improved thermal model for characteristics analysis of multi-link ultra-precision press system
Enlai Zheng,Shilu Xie,Jin Zhang,Yue Zhu,Xiao Zhao,Xiangze Lin,Min Kang 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.1
In traditional models, only the effect of temperature change of bearings on the heat generation power and thermal contact resistance is considered. But the effect of bearing stiffness and flexibility of crank shaft on the heat generation power is often neglected, thereby impairing the accuracy of the thermal analysis. Therefore, a better thermal model is demanded to accurately analyse the thermal characteristics of a Multi-link ultra-precision press system (MLUPPS). By combining the effect of stiffness of bearing and flexibility of crank shaft on the heat generation power, an improved thermal model of MLUPPS was developed in this work. The model was based on as-derived kinematic and dynamic equations of Multi-link transmission mechanism (MLTM) and flexible dynamic model of crankshaft-bearing system. The dimension chain of thermal error is constructed to analyse the dimensional error between the slider and the work table at the position of Bottom dead point (BDP). The developed thermal model of MLUPPS and its analysis results from this model are in good agreement with the measurement results, and that is more accurate than the traditional one. The simulation results reveal that the maximum temperature rise of MLUPPS occurs at the crank shaft, and the dimensional error between the slider and the work table at the position of BDP is due to thermal expansion fluctuation before the generation and conduction of heat power reaches balance. The temperature rise and thermal error of MLUPPS under different rotation speeds, piling forces and bearing stiffness were also studied.
Johnson, Derek Christopher,Bhatta, Madhav Prasad,Gurung, Santosh,Aryal, Shilu,Lhaki, Pema,Shrestha, Sadeep Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.19
Background: This study assessed human papillomavirus (HPV), cervical cancer, and HPV vaccine knowledge and awareness among women in two sub-populations in Nepal - Khokana, a traditional Newari village in the Lalitpur District about eight kilometers south of Kathmandu, and Sanphebagar, a village development committee within Achham District in rural Far-Western Nepal. Methods: Study participants were recruited during health camps conducted by Nepal Fertility Care Center, a Nepali non-governmental organization. Experienced staff administered a Nepali language survey instrument that included questions on socio-demographics, reproductive health and knowledge on HPV, cervical cancer, and the HPV vaccine. Results: Of the 749 participants, 387 (51.7%) were from Khokana and 362 (48.3%) were from Sanphebagar. Overall, 53.3% (n=372) of women were aware of cervical cancer with a significant difference between Khokana and Sanphebagar (63.3% vs 43.0%; p=0.001). Overall, 15.4% (n=107) of women had heard of HPV and 32% (n=34) of these women reported having heard of the HPV vaccine. If freely available, 77.5% of the women reported willingness to have their children vaccinated against HPV. Factors associated with cervical cancer awareness included knowledge of HPV (Khokana: Odds Ratio (OR)=24.5; (95% Confidence Interval (CI): 3.1-190.2, Sanphebagar: OR=14.8; 95% CI: 3.7-58.4)) and sexually transmitted infections (Khokana: OR=6.18; 95% CI: 3.1-12.4; Sanphebagar: OR=17.0; 95% CI: 7.3-39.7) among other risk factors. Conclusions: Knowledge and awareness of HPV, cervical cancer, and the HPV vaccine remains low among women in Khokana and Sanphebagar. Acceptance of a freely available HPV vaccine for children was high, indicating potentially high uptake rates in these communities.
Mortality risk attributable to high and low ambient temperature: a multicountry observational study
Gasparrini, Antonio,Guo, Yuming,Hashizume, Masahiro,Lavigne, Eric,Zanobetti, Antonella,Schwartz, Joel,Tobias, Aurelio,Tong, Shilu,Rocklö,v, Joacim,Forsberg, Bertil,Leone, Michela,De Sario, Manuela Elsevier 2015 The Lancet Vol.386 No.9991
<P><B>Summary</B></P><P><B>Background</B></P><P>Although studies have provided estimates of premature deaths attributable to either heat or cold in selected countries, none has so far offered a systematic assessment across the whole temperature range in populations exposed to different climates. We aimed to quantify the total mortality burden attributable to non-optimum ambient temperature, and the relative contributions from heat and cold and from moderate and extreme temperatures.</P><P><B>Methods</B></P><P>We collected data for 384 locations in Australia, Brazil, Canada, China, Italy, Japan, South Korea, Spain, Sweden, Taiwan, Thailand, UK, and USA. We fitted a standard time-series Poisson model for each location, controlling for trends and day of the week. We estimated temperature–mortality associations with a distributed lag non-linear model with 21 days of lag, and then pooled them in a multivariate metaregression that included country indicators and temperature average and range. We calculated attributable deaths for heat and cold, defined as temperatures above and below the optimum temperature, which corresponded to the point of minimum mortality, and for moderate and extreme temperatures, defined using cutoffs at the 2·5th and 97·5th temperature percentiles.</P><P><B>Findings</B></P><P>We analysed 74 225 200 deaths in various periods between 1985 and 2012. In total, 7·71% (95% empirical CI 7·43–7·91) of mortality was attributable to non-optimum temperature in the selected countries within the study period, with substantial differences between countries, ranging from 3·37% (3·06 to 3·63) in Thailand to 11·00% (9·29 to 12·47) in China. The temperature percentile of minimum mortality varied from roughly the 60th percentile in tropical areas to about the 80–90th percentile in temperate regions. More temperature-attributable deaths were caused by cold (7·29%, 7·02–7·49) than by heat (0·42%, 0·39–0·44). Extreme cold and hot temperatures were responsible for 0·86% (0·84–0·87) of total mortality.</P><P><B>Interpretation</B></P><P>Most of the temperature-related mortality burden was attributable to the contribution of cold. The effect of days of extreme temperature was substantially less than that attributable to milder but non-optimum weather. This evidence has important implications for the planning of public-health interventions to minimise the health consequences of adverse temperatures, and for predictions of future effect in climate-change scenarios.</P><P><B>Funding</B></P><P>UK Medical Research Council.</P>
A multi-country analysis on potential adaptive mechanisms to cold and heat in a changing climate
Vicedo-Cabrera, Ana M.,Sera, Francesco,Guo, Yuming,Chung, Yeonseung,Arbuthnott, Katherine,Tong, Shilu,Tobias, Aurelio,Lavigne, Eric,de Sousa Zanotti Stagliorio Coelho, Micheline,Hilario Nascimento Sal Elsevier 2018 Environment international Vol.111 No.-
<P><B>Abstract</B></P> <P><B>Background</B></P> <P>Temporal variation of temperature-health associations depends on the combination of two pathways: pure adaptation to increasingly warmer temperatures due to climate change, and other attenuation mechanisms due to non-climate factors such as infrastructural changes and improved health care. Disentangling these pathways is critical for assessing climate change impacts and for planning public health and climate policies. We present evidence on this topic by assessing temporal trends in cold- and heat-attributable mortality risks in a multi-country investigation.</P> <P><B>Methods</B></P> <P>Trends in country-specific attributable mortality fractions (AFs) for cold and heat (defined as below/above minimum mortality temperature, respectively) in 305 locations within 10 countries (1985–2012) were estimated using a two-stage time-series design with time-varying distributed lag non-linear models. To separate the contribution of pure adaptation to increasing temperatures and active changes in susceptibility (non-climate driven mechanisms) to heat and cold, we compared observed yearly-AFs with those predicted in two counterfactual scenarios: trends driven by either (1) changes in exposure-response function (assuming a constant temperature distribution), (2) or changes in temperature distribution (assuming constant exposure-response relationships). This comparison provides insights about the potential mechanisms and pace of adaptation in each population.</P> <P><B>Results</B></P> <P>Heat-related AFs decreased in all countries (ranging from 0.45–1.66% to 0.15–0.93%, in the first and last 5-year periods, respectively) except in Australia, Ireland and UK. Different patterns were found for cold (where AFs ranged from 5.57–15.43% to 2.16–8.91%), showing either decreasing (Brazil, Japan, Spain, Australia and Ireland), increasing (USA), or stable trends (Canada, South Korea and UK). Heat-AF trends were mostly driven by changes in exposure-response associations due to modified susceptibility to temperature, whereas no clear patterns were observed for cold.</P> <P><B>Conclusions</B></P> <P>Our findings suggest a decrease in heat-mortality impacts over the past decades, well beyond those expected from a pure adaptation to changes in temperature due to the observed warming. This indicates that there is scope for the development of public health strategies to mitigate heat-related climate change impacts. In contrast, no clear conclusions were found for cold. Further investigations should focus on identification of factors defining these changes in susceptibility.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Evidence on adaptation is crucial for the assessment of climate change impacts. </LI> <LI> Most of the studied countries showed a strong reduction in heat vulnerability. </LI> <LI> We found more diffuse patterns on cold-mortality trends. </LI> <LI> Pace of decrease in heat susceptibility was faster than the observed warming. </LI> <LI> There is scope for development of mitigation strategies of climate change impacts. </LI> </UL> </P>
Predicted temperature-increase-induced global health burden and its regional variability
Lee, Jae Young,Kim, Ho,Gasparrini, Antonio,Armstrong, Ben,Bell, Michelle L.,Sera, Francesco,Lavigne, Eric,Abrutzky, Rosana,Tong, Shilu,Coelho, Micheline de Sousa Zanotti Stagliorio,Saldiva, Paulo Hila Elsevier 2019 Environment international Vol.131 No.-
<P><B>Abstract</B></P> <P>An increase in the global health burden of temperature was projected for 459 locations in 28 countries worldwide under four representative concentration pathway scenarios until 2099. We determined that the amount of temperature increase for each 100 ppm increase in global CO<SUB>2</SUB> concentrations is nearly constant, regardless of climate scenarios. The overall average temperature increase during 2010–2099 is largest in Canada (1.16 °C/100 ppm) and Finland (1.14 °C/100 ppm), while it is smallest in Ireland (0.62 °C/100 ppm) and Argentina (0.63 °C/100 ppm). In addition, for each 1 °C temperature increase, the amount of excess mortality is increased largely in tropical countries such as Vietnam (10.34%p/°C) and the Philippines (8.18%p/°C), while it is decreased in Ireland (−0.92%p/°C) and Australia (−0.32%p/°C). To understand the regional variability in temperature increase and mortality, we performed a regression-based modeling. We observed that the projected temperature increase is highly correlated with daily temperature range at the location and vulnerability to temperature increase is affected by health expenditure, and proportions of obese and elderly population.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Future health burden with respect to CO<SUB>2</SUB> increase was projected in 28 countries. </LI> <LI> Future temperature and mortality were compared across locations. </LI> <LI> Daily temperature range determines the rate of temperature increase. </LI> <LI> Amount of health expenditure determines the vulnerability to temperature change. </LI> </UL> </P>