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401.
Abstract

Most modern pesticides are expensive. Application of excessive dosage rates is likely to cause undesirable biological side‐effects and is economically wasteful. Non‐uniform distribution of the spray cloud, or application at the wrong time, may result in failure to control the pest. It is the responsibility of the field operator to acquire sufficient knowledge and skill to ensure proper use of the control agents, to increase efficiency of their usage and to reduce unwanted side‐effects. To achieve this goal, he must take into consideration the various physical factors that govern field performance of pesticides.

A simple relationship exists between the spray volume and emission rate used, and droplet size produced. The use of extremely low spray volumes (i.e., those less than 2.0 litre per ha) for forest insect control in Canada, as opposed to higher volumes used in agriculture, necessitates the release of fine droplets (ranging from 20 to 70 μm in diameter) to obtain adequate coverage of the target area. These droplets take a long time to sediment downwards, evaporate in‐flight, become smaller in size and/or form powdery residues, thus contributing to off‐target drift and impaired droplet adhesion to target surfaces. Physical factors such as rain washing, degradation by sunlight and erosion by wind also influence the longevity of pesticide deposits on foliage which is crucial during the critical period of pest control.

Factors affecting the mode of entry into insects are related to the type of ingredients used in formulation. If a pesticide acts via crawling contact, formulations which would provide surface deposits would be more beneficial than emulsions or oil‐based mixes which tend to undergo penetration into foliar cuticle. Physical factors that affect field performance of a pesticide tank mix are related to phase separation and ‘breakdown of emulsions’ in the application equipment; ‘agglomeration and caking’ of wettable powder dispersions at the bottom of the tank; impaired flow behaviour of highly viscous formulations; and coarse atomization of high‐viscosity tank mixes leading to poor target cover.  相似文献   
402.
An energy discriminate CR-39® nuclear track etch dosimeter for use in a 220Rn and 222Rn gas monitor has been developed and experimentally assessed. It utilises a thin film of Mylar® C to attenuate the alpha particle energies to allow only the damage tracks created by the 8.785 MeV alpha particles emitted from 212Po of the 232Th decay chain to be registered in the CR-39® plaque, allowing for the direct measurement of 220Rn gas concentrations. The dosimeter was developed through a combination of experimental investigations and theoretical simulations using the Monte Carlo ion transport modelling program Stopping and Range of Ions in Materials (SRIM 2008). A film thickness of 54 μm has been shown to attenuate all alpha energies less then 7.7 MeV.  相似文献   
403.
Assessment of the environmental and radiological consequences of a nuclear accident requires the management of a great deal of data and information as well as the use of predictive models. Computerised Decision Support Systems (CDSS) are essential tools for this kind of complex assessment and for assisting experts with a rational decision process. The present work focuses on the assessment of the main features of selected state-of-the-art CDSS for off-site management of freshwater ecosystems contaminated by radionuclides. This study involved both developers and end-users of the assessed CDSS and was based on practical customisation exercises, installation and application of the decision systems. Potential end-users can benefit from the availability of several ready-to-use CDSS that allow one to run different kinds of models aimed at predicting the behaviour of radionuclides in aquatic ecosystems, evaluating doses to humans, assessing the effectiveness of different kinds of environmental management interventions and ranking these interventions, accounting for their social, economic and environmental impacts. As a result of the present assessment, the importance of CDSS “integration” became apparent: in many circumstances, different CDSS can be used as complementary tools for the decision-making process. The results of this assessment can also be useful for the future development and improvement of the CDSS.  相似文献   
404.
通过了解国内外化学污染事故的现状,分析了化学污染事故的严重性及其特征,结合我国现有的环境风险管理状况,探讨了化学污染事故环境风险管理的途径。  相似文献   
405.
Radium-226 is a significant source of radon-222 which enters buildings through soil, construction materials or water supply. When cigarette smoke is present, the radon daughters attach to smoke particles. Thus, the alpha radiation to a smoker’s lungs from the natural radon daughters is increased because of smoking. To investigate whether the cigarette tobacco itself is a potential source of indoor radon, the α potential energy exposure level contents of radon (222Rn, 3.82d) and Thoron (220Rn, 55.60s) were measured in 10 different cigarette tobacco samples using CR-39 solid-state nuclear track detectors (SSNTDs). The results showed that the 222, 220Rn concentrations in these samples ranged from 128 to 266 and 49 to 148 Bqm−3, respectively. The radon concentrations emerged from all investigated samples were significantly higher than the background level. Also, the annual equivalent doses from the samples were determined. The mean values of the equivalent dose were 3.51 (0.89) and 1.44 (0.08) mSvy−1, respectively. Measurement of the average indoor radon concentrations in 20 café rooms was, significantly, higher than 20 smoking-free residential houses. The result refers to the dual (chemical and radioactive) effect of smoking as a risk factor for lung cancer.  相似文献   
406.
危险化学品公路运输事故新特点及对策研究   总被引:5,自引:2,他引:3  
统计分析了2008年1月~2010年5月我国发生的485起危险化学品公路运输事故。从事故发生的原因、事故涉及的化学品、事故造成的危害、事故发生的月份分布及年份变化等几个方面,分析了近年来危险化学品公路运输事故的新特点及变化规律。经统计分析,道路交通事故是引发危险化学品运输事故的主要原因之一;侧翻是危险化学品车辆最容易发生的道路交通事故;而随着我国高速公路的迅猛发展,追尾造成的危险化学品运输事故数量呈上升趋势;危险化学品公路运输过程中易燃液体事故起数最多,爆炸品和毒性物质事故造成的人员伤亡最严重;春节前后取代夏季,成为近两年危险化学品运输事故高发期。针对这些特点,对我国危险化学品公路运输安全管理与监控提出了建议。  相似文献   
407.

Introduction

Through a meta-analysis, this study investigated the relation of errors and violations from the Driver Behaviour Questionnaire (DBQ) to accident involvement.

Method

We identified 174 studies using the DBQ, and a correlation of self-reported accidents with errors could be established in 32 samples and with violations in 42 samples.

Results

The results showed that violations predicted accidents with an overall correlation of .13 when based on zero-order effects reported in tabular form, and with an overall correlation of .07 for effects reported in multivariate analysis, in tables reporting only significant effects, or in the text of a study. Errors predicted accidents with overall correlations of .10 and .06, respectively. The meta-analysis also showed that errors and violations correlated negatively with age and positively with exposure, and that males reported fewer errors and more violations than females. Supplementary analyses were conducted focusing on the moderating role of age, and on predicting accidents prospectively and retrospectively. Potential sources of bias are discussed, such as publication bias, measurement error, and consistency motif.

Impact on Industry

The DBQ is a prominent measurement scale to examine drivers’ self-reported aberrant behaviors. The present study provides information about the validity of the DBQ and therefore has strong relevance for researchers and road safety practitioners who seek to obtain insight into driving behaviors of a population of interest.  相似文献   
408.
区域综合公共安全管理模式及中国综合公共安全管理对策   总被引:5,自引:1,他引:4  
中国政府将公共安全事件分为4大类,即自然灾害、事故灾难、公众卫生和社会安全。中国的公共安全管理体制包括在中央一级成立国务院应急管理办公室,以及针对上述4类公共安全问题相应组建的以管理自然灾害为主的国家减灾委员会;以管理事故灾难为主的国家安全生产委员会;以管理公共卫生为主的中国爱卫会和以管理社会治安为主的中央综合治理委员会。在地方政府一级,一般与中央有关公共安全管理体制的机构相对应,也相应组建了地方政府的应急管理办公室和上述4类的公共安全管理的委员会。此外,国家出台了各类公共安全管理的应急预案,并针对一些主要的公共安全因素,相继制定了一系列法律、规定和决定。由此可以认为,中国公共安全的管理体制是“以中央为主,中央与地方政府相互配合”。中国公共安全管理机制是中央与地方政府的相关部门,在灾前、灾中与灾后分别承担相应的责任,至今还没有一个政府部门就某一种公共安全因素承担全部的备灾、应急与恢复和重建任务。国家的公共安全管理战略一直是以“预防为主,防抗救相结合”,2003年SARS事件后,各级政府重视公共安全管理工作中应急管理体系的建设。文章提出了区域综合公共安全管理模式,即灾区政府、企业、社区在灾前备灾、灾中应急、灾后恢复与重建的减灾全过程中,形成一个有机的整体。在此模式的指导下,针对中国公共安全管理体制与机制中存在的问题,提出了进一步改进中国各级政府综合公共安全管理的对策:一是加大公共安全信息的及时公开力度,建立国家和地方公共安全信息共享体系;二是建立公共安全管理的纵向、横向与综合协调机制,全面提高各级政府的综合公共安全管理能力;三是从源头上降低公共安全事件的发生频率,建立发展规划的“风险”评价制度;四是鼓励非政府组织在综合公共安全管理中发挥作用,建立社区综合公共安全管理体系;五是大力提高减灾资源的利用效率与效益,建设区域综合风险防范关键技术示范基地。  相似文献   
409.
灰色预测在平朔煤炭工业公司安全生产中的应用   总被引:1,自引:1,他引:0  
利用灰色系统理论,建立了平朔煤炭工业公司事故伤亡率的GM(1,1)动态预测模型,并采用残差修正方法,提高了预测精度.对于该矿山有效地控制安全事故的发生,减少其造成的经济损失起到了重要的作用.  相似文献   
410.
煤矿安全从业人员心理测试指标体系研究   总被引:1,自引:0,他引:1  
为了寻求有效解决煤矿安全人为事故屡禁不止问题的有效办法,探讨了煤矿作业对人提出的安全心理素质要求,对煤矿从业人员的心理因素与安全生产关系进行了工作分析与职务分析,建立了以能力与非能力因素为基本内容的心理测试指标体系,并对这一体系的科学性进行了验证.应用实践表明,该体系为从根本上解决煤矿安全问题提供了新的途径.  相似文献   
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