人体动力特性振动台试验研究

随着社会发展和经济水平的提高,人们对于生产、生活的环境质量要求也不断提升,因而环境振动已越来越多的引起了社会的关注,为了研究环境振动对人体的影响,需要了解人体动力特性和在振动环境下的响应。对20名受试者以站、坐、躺姿进行了水平两向输入白噪声的振动台试验,测得人体头、肩、腹、上肢、下肢五个部位的振动响应,通过对人体各部分振动频率与身高、体重、年龄的关系分析,给出了人体频率分布规律。     

基于响应曲面法的钠化焙烧-水浸法回收废加氢催化剂中有价金属工艺优化

为提高废加氢催化剂钠化焙烧-水浸分离工艺回收有价金属的效率,采用响应面法优化了废加氢催化剂钠化焙烧-水浸工艺条件,探讨了焙烧温度、焙烧时间、碳酸钠添加量、浸出温度和液固比对Mo、Al浸出率的影响,并确定了最优工艺条件;同时,采用热重-差示扫描量热法 (TG-DSC) 和X射线衍射法 (XRD) 分析了废催化剂预处理与钠化焙烧过程的物相变化。结果表明：适宜的预处理温度为400~500 ℃。随着预处理温度的升高,钼与铝结合生成Al₂(MoO₄)₃;Al₂(MoO₄)₃可参与钠化反应。在钠化焙烧温度为950 ℃、焙烧时间为2 h、碳酸钠与废加氢催化剂质量比为1.1∶1、浸出液固比为6：1、浸出温度为70 ℃的条件下,Mo的浸出率可达98%以上、Al的浸出率可达94%以上。当碳酸钠添加量较少时,未参与钠化反应的Mo和Al会结合生成Al₂(MoO₄)₃,从而造成Mo、Al浸出率降低。Mo、Al发生钠化反应的温度在700~1000 ℃之间;当焙烧温度为700 ℃时,钠化反应未大量发生;随着反应温度的提高,钠化反应大量发生,至950 ℃时钠化反应最充分。本研究结果可为废加氢催化剂钠化焙烧-水浸分离回收有价金属提供参考。     

电阻加热修复佳乐麝香污染土壤的工艺优化

佳乐麝香(Galaxolide,HHCB)是土壤中的一种新兴的半挥发性有机污染物,具有较高的毒性,需修复治理。电阻加热技术(electrical resistance heating,ERH)因加热均匀、效果好,逐渐被应用于有机污染土壤修复工程。采用自主研制的电阻加热装置,研究了加热过程中电场强度、土壤含水率和土壤粒径等因素对土壤HHCB去除效果的影响,并采用响应面法对工艺参数进行了优化。结果表明,土壤 HHCB去除率随电场强度和含水率的增大先增加后减小,随土壤粒径的增大而增大;在土壤含水率为40%、土壤粒径1~2 mm和电场强度12 V·cm⁻¹的条件下,加热6 h,HHCB去除效果最好,去除率达到了81.35%。通过响应曲面模拟优化得到的最佳工艺参数条件为,含水率39.07%、土壤粒径2.92 mm、电场强度12.64 V·cm⁻¹,在此条件下土壤HHCB的去除率为86.43%;在本实验条件下,3个因素对土壤HHCB去除率的影响为：含水率>土壤粒径>电场强度。本研究结果可为多环麝香污染土壤的修复提供参考。     

Seismic response mitigation of chemical plant components by passive control techniques

This paper deals with the applicability of seismic passive control in major-hazard chemical installations. The objective is to show numerically and experimentally the applicability of Passive Control Techniques (PCT) in industrial plants. Consequently, the main components of a process plant are classified and collected into a limited number of classes; for each class, the main damages caused by past earthquakes are described and the most vulnerable components are identified. A synthesis of the effects of earthquakes on the different typologies of process components is also presented and the most suitable innovative seismic protection systems, in particular passive control techniques (PCT), are acknowledged. Finally, the effectiveness of PCT in reducing the seismic response of process plant components is proved by three representative case studies: a base isolated above-ground storage tank, a distillation column connected by elastoplastic dampers to the adjacent service frame and an application of non-conventional Tuned Mass Dampers to a support frame.     

The barriers impeding precautionary behaviours by undocumented immigrants in emergencies: The Hurricane Ike experience in Houston,Texas, USA

Emergency management tends to be planned for legal, resident populations that are responsive to mainstream channels of communication and enforcement. For many areas prone to extreme events and emergencies, populations are also composed of transitory tourists, temporary visitors and migrant workers. This latter group may be a large population and, while not completely invisible to residents, may prefer obscurity and concealment within the social landscape. Tending towards poverty, technologically disconnected and linguistically isolated, undocumented migrants seek employment and attempt to avoid local law enforcement and immigration officials for fear of imprisonment and deportation. In this context, the behaviours prompted by developing public emergencies will be different for undocumented migrants than for the population at large. We examine the experience of 135 Hispanic undocumented migrants in the coastal zone of Houston-Galveston, Texas to understand the factors and issues that influence decision making and behaviours under region-wide mandatory evacuation conditions. Undocumented migrants’ decisions to evacuate rest upon: the presence (or absence) of family and/or children, their access to risk information that they find meaningful and rational and is in harmony with their pre-conceptions about their circumstances, their openness to information that either confirms their experiences or confronts rumour-generated biases they carry, their familiarity with social groups and governmental agencies and the services they offer, and the outcome of their risk analyses that consider the dangers of remaining in situ against the danger of exposing themselves to discovery as ‘illegal aliens’. The results suggest that emergency management plans ought to promote the dispelling of rumours that weaken the effect of emergency communication, promote non-emergency outreach to peripheral populations through community groups, and promote better, basic, non-technical, Spanish-language media through mainstream conduits (i.e. the most commonly watched non-Spanish television channels) that do not require high-tech devices or advanced understanding of visual media tools.     

磷肥种类对李氏禾富集铜、铬的影响及其生理响应

植物修复是现下环境和生态领域研究的热门话题.环境中的铜、铬等重金属复合污染问题越发严重,在水环境修复和治理的方法中,植物修复技术的优越性越发显著.该文旨在加深磷对李氏禾累积重金属铜和铬复合污染的认识.施磷是一种重要的农艺措施,其在提高植物修复复合污染水体效率方面的效果不容忽视.该实验研究李氏禾(Leersia Hexa...     

高速动能弹撞击装甲结构引起的螺栓连接失效及部件过载损伤研究

目的 验证和揭示高速动能弹对装甲结构的损伤机理。方法 聚焦高速动能弹打击装甲目标时,弹道冲击造成的靶标结构连接失效及部件过载损伤这2种损伤效应,以典型螺栓连接为研究对象,采用高速球形弹丸撞击螺栓连接结构的小尺寸试验对数值模拟方法和材料模型参数进行校验。在此基础上,采用数值模拟和冲击响应谱分析方法对高速动能弹打击全尺寸坦克进行模拟分析,获得撞击过程螺栓连接失效特征、主要影响因素及坦克典型位置部件的冲击加速度曲线和冲击响应谱曲线。结果 在小尺寸试验中,动能输入为0.042MJ时,螺栓连接未发生失效;但25.6MJ动能输入全尺寸坦克时,螺栓发生断裂而使连接失效。数值模拟结果揭示了螺栓发生断裂的主要原因。结论 输入动能大小、连接螺栓直径、模拟设备部件质量和撞击位置为螺栓是否断裂的主要影响因素。坦克某些位置的冲击响应谱曲线高于军用标准给出的临界曲线的下限甚至上限,表明这些位置的部件因高过载损伤导致失效的概率较高。     

玄武岩砖红壤磷肥活化效果及其机理研究

应用不同活化剂处理不同性质的磷肥,并对其在玄武岩砖红壤中的生物效应及作用机理进行了研究.结果显示在玄武岩砖红壤上,活化剂处理磷肥均能显著提高蔬菜生物量,其中对磷矿粉无机活化剂处理后的生物效应最大;对磷铵则是有机2号活化剂的生物效应最大.玄武岩砖红壤中的铁、锰与磷素有效性关系密切,且在还原条件下的土壤锰对磷的固定作用更大;硅可促进土壤中磷的释放;供试活化剂不仅可促进难溶磷的释放,还可控释水溶性磷,使土壤供磷性能平稳.在体系中,活化剂对磷的促释和控释机理在于通过对土壤铁、锰、铝含量的调节而实现对磷的活化.     

From Policy to Practice: Challenges in Infant Feeding in Emergencies During the Balkan Crisis

The preparation and dissemination of policy statements are necessary but insufficient to prevent the inappropriate use of infant-feeding products in emergencies. The widespread failure of humanitarian agencies operating in the Balkan crisis to act in accordance with international policies and recommendations provides a recent example of the failure to translate infant-feeding policies into practice. This article explores the underlying reasons behind the failures which include: (1) the weak institutionalisation of policies; (2) the massive quantities of unsolicited donations of infant-feeding products: (3) the absence of monitoring systems; (4) inadequate co-ordination mechanisms; (5) the high costs of correcting mistakes; and (6) the cumulative effects of poor practice. Efforts to uphold best practice during the crisis are also documented. Finally, the article identifies actions that could be undertaken in advance of and during future emergencies to enhance the application of infant feeding policies in emergencies.     

华北1743-1744年与1876-1878年旱灾中的政府粮食调度与社会后果对比

以《清实录》等清代档案文献为主要历史信息源,挑选华北地区清代盛期(1743-1744年)和晚期(1876-1878年)分别发生的两次典型旱灾,对灾害气候背景和灾情、政府措施(特别是政府主导的跨区粮食调度)、社会后果(人口迁徙和动乱)等信息进行整理并分别对比,可以发现1743-1744年旱灾期间政府的粮食调度体现出粮食数量大、来源渠道广、调度效率高等鲜明特点,并取得了良好的社会效果;而1876-1878年旱灾则反之,粮食数量及来源有限,且转运效率极低,由此引发严重社会后果。这种转变,发生在主要余粮产区农业凋敝、南北粮食运道(大运河)阻断、漕运及仓储制度衰败的时代背景之下,重灾区空间分布带来的交通通达性差异,也在客观上影响了粮食调度的效率。