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951.
基于性能的结构抗风设计理论框架   总被引:4,自引:0,他引:4  
提出了基于性能的结构抗风设计理论框架,将风压强度划分为4个设计风压等级(弱风压、中风压、强风压及超强风压),将人体振动舒适度划分为6个等级(无振感、轻微振感、中等振感、烦恼、非常烦恼和无法忍受)、三种振动水平(与人的舒适感相关的振动水平、与人正常工作和操作有关的振动水平、与人的生理健康直接相关的振动水平)。结合不同类别建筑物的性能需求及人体振动舒适度的要求,将结构风振性能水准划分为4种状态(性能健康、性能亚健康、性能病态及性能丧失),将结构风振性能目标划分为5个等级(A、B、C、D、E)。提出了结构抗风概念设计与计算分析的一般原则,给出了结构性能抗风安全性评价及社会经济评价基本内容的建议。  相似文献   
952.
Objective: The primary purpose of this study was to examine the association between variations in visual behavior measures and subjective sleepiness levels across age groups over time to determine a quantitative method of measuring drivers' sleepiness levels.

Method: A total of 128 volunteer drivers in 4 age groups were asked to finish 2-, 3-, and 4-h continuous driving tasks on expressways, during which the driver's fixation, saccade, and blink measures were recorded by an eye-tracking system and the subjective sleepiness level was measured through the Stanford Sleepiness Scale. Two-way repeated measures analysis of variance was then used to examine the change in visual behavior measures across age groups over time and compare the interactive effects of these 2 factors on the dependent visual measures.

Results: Drivers' visual behavior measures and subjective sleepiness levels vary significantly over time but not across age groups. A statistically significant interaction between age group and driving duration was found in drivers' pupil diameter, deviation of search angle, saccade amplitude, blink frequency, blink duration, and closure duration. Additionally, change in a driver's subjective sleepiness level is positively or negatively associated with variation in visual behavior measures, and such relationships can be expressed in regression models for different period of driving duration.

Conclusions: Driving duration affects drivers' sleepiness significantly, so the amount of continuous driving time should be strictly controlled. Moreover, driving sleepiness can be quantified through the change rate of drivers' visual behavior measures to alert drivers of sleepiness risk and to encourage rest periods. These results provide insight into potential strategies for reducing and preventing traffic accidents and injuries.  相似文献   

953.

Introduction

Fall-related occupational injuries and fatalities are serious problems in the U.S. construction industry, especially incidents related to unguarded holes. The National Institute for Occupational Safety and Health, Division of Safety Research, Morgantown, WV conducted a project to evaluate the effectiveness of guardrail systems to prevent falls through roof and floor holes.

Methods

Two commercial edge-protection products were evaluated when used as perimeter guarding around a roof hole. Installations of the commercial products were compared to job-built guardrails constructed of 2 × 4 construction-grade lumber. Occupational Safety and Health Administration (OSHA) regulations require that “a force of at least 200 pounds” must be supported by the top rail of a guardrail system “in any outward or downward direction at any point along the top edge.” A laboratory testing system was developed to evaluate this requirement. A dynamic 200-lb force was generated against the top rail using a weighted manikin mounted on a hinged steel frame. Nine construction workers, who served as test subjects, each built five different guardrail configurations.

Results

All 45 configurations met the 200-lb OSHA requirement. Installation time for one commercial product was 32% quicker than the job-built configuration (25.6 min vs. 37.9 min).

Impact on Industry

This study: (a) indicates that the two edge-protection products can be used as perimeter guarding; (b) highlights the importance of using proper materials and fasteners to construct guardrails to protect workers from falling into unguarded roof and floor holes; and (c) discusses an overall-strength-testing methodology that can be used by fall-protection researchers.  相似文献   
954.
印染行业清洁生产技术   总被引:3,自引:0,他引:3  
论述了目前印染行业水污染的现状及原因,指出调整产业结构、应用新工艺、大力提倡节约用水、清沽生产将是印染行业实现可持续发展的必由之路。  相似文献   
955.
痕量壬基酚及相关化合物的样品预处理和测定   总被引:14,自引:1,他引:14  
对近年来环境样品中痕量内分泌干扰物壬基酚及相关化合物的分离富集方法和测定技术的研究进展进行了综合评述。重点讨论了索氏提取、液液萃取、液膜分离、回流萃取、固相萃取、固相微萃取、超临界流体萃取、超声提取八种样品预处理方法和气相色谱质谱联用、高效液相色谱两种测定方法,而且针对以上方面提出了尚需进一步研究的问题。  相似文献   
956.
Learning from incidents is considered a very important source for learning and improving safety in the process industries. However, the effectiveness of learning from reported incidents can often be questioned. Therefore, there is a need to be able to evaluate the effectiveness of learning from incidents, and for that purpose we need methods and tools. In this paper, a method is described for evaluating the effectiveness of learning, based on the idea of “level of learning” of the lessons learned. The level of learning is expressed in terms of how broadly the lesson learned is applied geographically, how much organizational learning is involved and how long-lasting the effect of learning is. In the 6-step method, the incidents reported in a typical incident learning system are evaluated both for the actual and the potential level of learning in a semi-quantitative way with different tools. The method was applied in six process industries on a large number of incidents. The method was found to be very useful and to give insights of aspects that influence the learning from incidents.  相似文献   
957.
Toxiceffectsofseleniumonmarinefish¥/ZhangYuanxun(ShanghaiInstituteofNuclearResearch,ChineseAcademyofsciences,Shanghai201800,C...  相似文献   
958.

针对我国2030年碳达峰要求,立足当前经济和能源需求快速发展的现状,选取2000—2020年时间序列数据,采用Tapio脱钩模型,定量分析中国能源消费CO2排放量与经济增长的脱钩状况;建立扩展的STIRPAT模型,探讨中国能源消费CO2排放的影响因素;运用情景分析法对基准情景(S0)、产业结构优化情景(S1)、能源结构优化情景(S2)、多要素优化情景(S3)4种情景下的CO2排放量进行了预测。结果表明:中国能源消费CO2排放量与经济增长之间的脱钩状态总体以弱脱钩为主。人口规模、能源消费结构、第二产业占比、城镇化率、人均GDP、第三产业占比、碳排放强度每变动1%时,分别引起能源消费CO2排放量的2.857%、0.879%、0.836%、0.623%、(0.221+0.011ln A1)%、0.241%、0.132%的变动。基准情景下中国在2030年之前不能实现碳达峰,产业结构优化情景和能源结构优化情景下在2030年实现碳达峰,峰值分别为110.90亿和109.18亿t,多要素优化情景下可以在2030年之前实现碳达峰,峰值为105.03亿t。

  相似文献   
959.
中国工业用水效率的动态演进及驱动因素研究   总被引:1,自引:0,他引:1  
选取中国31个省级行政区1999~2014年的面板数据,运用Frontier4.1软件测算了我国各省区历年工业用水效率值,还通过聚类分析方法将各省区分为高效率组、中效率组、低效率组进行工业用水效率差异分析,接着选择自然资源、经济水平、工业发展、工业结构、用水结构和政府影响这6个因素,构建Tobit回归模型对这6个驱动因素分全国、高、中、低效率组样本分别对工业用水效率的影响进行实证分析。研究结论如下:我国工业用水效率平均值呈现逐年上升的趋势;东、中、西部地区的工业用水效率值差异较为明显;工业用水效率整体分布从东南向西北逐渐递减的趋势;我国各省区的工业用水效率处于一种较快的增长趋势且地区间的工业用水效率差距在不断缩小;人均水资源量与工业用水效率呈负相关关系;经济水平驱动因素和工业发展驱动因素都与工业用水效率存在很强的正相关关系;合理的工业结构可以显著提高工业用水效率;政府作为对于工业用水效率的提高也是至关重要的。  相似文献   
960.
With the fast development of Qingdao’s economy, the energy consumption is increasing significantly. In this paper, based on the energy statistic data in Qingdao area from 2010 to 2015, energy consumption structure was analyzed, indicating the existence of single energy structure; that is, coal, petroleum, and natural gas are dominant in the area. Thus, some issues between energy supply and demand have been brought. To solve present problem, we put forward to formulate the development strategy of energy, including energy savings, the exploitation of petroleum and natural gas resources, the development and utilization of renewable energy sources, and energy policy. It is worthy of mentioning that, according to the geological investigation, the shale gas may be abundant in Qingdao area and the gas resource amount estimated is huge. This is our first finding, important for developing unconventional energy and adjusting the energy structure in Qingdao in the future. Therefore, we suggest that Qingdao government should take action to develop local new energy resources for satisfying the energy demand.  相似文献   
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