电梯安全钳型式试验结果分析

为了提高电梯安全钳的动作效能,以电梯型式试验为基础,模拟电梯因断绳、严重超载等原因导致轿厢坠落这一典型危害事故下安全钳动作,根据实验结果对安全钳失效及合格情况分别进行对比分析,通过对轿厢坠落减速度变化曲线、安全钳楔块磨损程度分析、楔块成分及硬度测试分析等综合比较,分析安全钳失效的可能原因.结果表明,安全钳制动效果与楔块的性能不可分,楔块性能主要从其耐磨性能、材质及硬度等方面考量.研究结果对电梯安全钳设计制造有一定的借鉴作用,有利于电梯安全钳安装和使用质量的提升.     

Influence of coal particles on methane/air mixture ignition in a heated environment

The temperature at which coal dust glows is normally much lower than the auto-ignition temperature (AIT) of methane/air mixtures, and thus a better understanding is needed regarding methane/air ignition in a heated environment in the presence of coal particles. A horizontal tube apparatus was used to test the effect of brown coal and two kinds of bituminous and anthracite on methane/air combustibility. For the four coal samples tested, the presence of coal particles significantly reduced the minimum temperature for ignition of methane/air mixtures in a heated environment. No. 1 bituminous coal with 12 mm diameter decreased the ignition temperature value from 595 to 500 °C. It is thought that pre-ignition of low-AIT volatiles emitted from the heated coal particles ignited the methane/air mixtures. Volatiles, sulfur content, and large porosity of piled coal particles all enhanced ignition of methane/air mixtures in a hot environment, while water content and small particle size reduced ignition. For anthracite, no ignition occurred when temperatures of the heated environment were lower than the AIT of methane (595 °C), except for the 12-mm-diameter sample. Anthracite did not readily ignite methane/air mixtures and the ignition mechanism was somewhat similar to that of a burning cigarette.     

Development of Micropore Mufflers

Research on micropore mufflers was started in the middle of the 1970s. In this article we have summarized and systematized what has been done in the past 20 years. Some expressions, derivations, and calculation curves have been formally modified to make them easier to understand and apply. Some new considerations have been added. The main purpose of this article is to introduce the fundamentals, theories, and calculations that are useful for the design of a micropore muffler. Therefore, we have not included any experiments. Direct and indirect experimental proofs can be found in the given relevant references. Micropore mufflers are grouped into two classes, simple micropore mufflers and expansion micropore mufflers. The latter have additional noise reduction due to flow expansion. Noise reduction and flow are two important aspects that have been discussed in detail.     

进口废塑料环境保护管理研究

随着塑料资源的大量消耗,废塑料的利用引起了社会的高度重视。工艺简单,投入成本少,入行门槛低导致部分废塑料加工利用企业技术水平低、管理模式差、环境污染重。为规范进口废塑料行业,通过调研统计、实验分析、咨询论证和研究了进口废塑料环境保护管理规定,对进口废塑料企业的规模、设备、人员和管理等方面提出了要求,为进一步规范提升进口废塑料行业提供技术支撑。     

环洞庭湖经济圈旅游产业协同发展探析

环洞庭湖经济圈的可持续发展问题正引起国家相关部门的高度重视,而环洞庭湖经济圈旅游产业的协同发展是实现该区域可持续发展的重要途径。从协同学理论视角出发,阐析区域旅游产业协同发展的理论机理,解析环洞庭湖经济圈旅游产业协同发展的现实基础与主要障碍,提出推进环洞庭湖经济圈旅游产业协同发展的政策建议。     

废旧电脑拆解工艺与资源化案例研究

以某再生资源公司的废旧电脑拆解为案例进行研究,介绍了工艺技术、拆解回收各种资源的数据。研究结果表明,我国废旧电脑人工拆解-破碎-冶炼相结合的工艺,是电子废弃物循环利用、资源高效回收、减少环境风险的较好工艺技术,符合固废处理的3R(替代、减少、优化)原则。     

可燃粉尘爆炸基础研究综述

对工业可燃粉尘爆炸基础研究进行了综述.对粉尘爆炸领域有史以来的主要基础研究成果进行了高度概括,内容涉及引起粉尘爆炸的可燃物质、影响粉尘云可燃性和爆炸性的因素、粉尘云在空气中的燃烧、引发粉尘爆炸的点火源、一次和二次粉尘爆炸、粉尘闪燃、杂混物的爆炸及粉尘云爆轰8个方面.回顾了粉尘爆炸的预防和缓解措施进展,指出了本质安全设计的意义.最后针对纳米颗粒粉尘的爆炸特性进行了探讨,通常粉尘的最小点火能随粉尘粒径减小而减小、爆炸指数随粉尘粒径减小而增大,这种趋势直到粉尘粒径减小到1～10 μm一直存在,但这种趋势可能不会持续到纳米粉体级别,可能的两个原因是纳米粉体的难于分散和凝并作用.     

新型氨化菌丝体吸附剂的制备及吸附典型内分泌干扰物的研究

以产黄青霉(Penicillium chrysogenum)菌丝体为原料,通过2步化学反应将含有大量氨基的聚乙烯亚胺(PEI)嫁接到菌丝体表面,优化反应条件,得到最佳的氨化菌丝体吸附剂.该氨化吸附剂的等电点为pH 10.2,是一种表面带正电荷的菌丝体吸附剂,能有效吸附水中的阴离子内分泌干扰物五氯酚钠(PCP)、2,4二氯苯氧乙酸(2,4-D)和全氟辛烷磺酸钾(PFOS).3种污染物的吸附等温线符合Langmuir方程,15℃时最大吸附量分别为342.9、234.1、1725.6 mg/g.热力学计算表明,3种污染物的吸附均是自发发生的,2,4-D和PFOS的吸附是吸热反应,而PCP是放热反应.     

世界自然遗产地面临的威胁及中国的保护对策

中国的自然遗产事业方兴未艾,但自然遗产地的保护状况令人担忧。论文以广泛的基础资料收集为前提,分析论证了自然遗产地保护的完整性原则,并对全球范围内世界自然遗产地的威胁因素进行了定量化统计评价。结合中国世界自然遗产地的保护状况,提出了中国自然遗产地的保护对策。     

厌氧生物流化床处理啤酒废水动力学研究

通过合理假设推导出了厌氧生物流化床处理啤酒废水过程中的基质降解的动力学模型和微生物生长的动力学模型,并通过实验测出了模型中的相关参数.