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221.
文章以国内典型压力容器用材245R为例,采用GB/T19624~断裂力学评价方法对于《压力容器定期检验规程》表5、表6中的超标非圆形缺陷可接受准则的安全裕度进行评价,评价结果表明其中可接受准则的部分规定不够保守,就此作者给出相关的修改建议。  相似文献   
222.
Abstract

The use of agrochemicals like crop protecting agents, veterinary disinfectants, and wood preservatives may result in (un)intentional exposure of the environment, animals and man. This paper deals with current testing strategies to assess the potential health risks for humans exposed to these chemicals during production or application or via consumption of foods containing pesticide residues.

Principles and procedures for safety assessment of pesticide residues in food as developed by WHO/FAO are described. Different types of toxicity studies in mammalian test animal species are discussed and a strategy is outlined in order to characterize the toxicity profile of a compound and the relationship between applied doses and adverse effects. Safety testing of agrochemicals should be carried out in relation to its intended use, and in particular attention will be paid to toxicity testing of residues of pesticides in food. Extrapolation of results from animal studies to humans and the use of safety factors is discussed.

Besides the use of animal protocol studies for safety testing of agrochemicals, the potential use of in‐vitro models derived from organs and tissues of animals is discussed. Data on the in‐vitro metabolism of thiabendazole, aldicarb and alachlor are discussed in order to demonstrate that such data may complement or partly substitute whole animal experimentation.

Principles and procedures for safety testing of residues of agrochemicals in food as applied during the last three decades, constitute a ‘safety‐first’ approach, providing sufficient safety margins for the consumer of foods which may contain low levels of residues of agrochemicals.  相似文献   
223.
Abstract

The importance of field surveys to provide data on acute pesticide hazards is discussed. The types of questions which small field surveys of pesticide exposure should answer are presented. In addition to protective clothing, the value of distance, time, and personal hygiene in reducing exposure are considered. Finally, the importance of an adequate data base for the development of protocols and guidelines for public protection is discussed.  相似文献   
224.
In a recently published annex to the National Environmental Policy Plan of the Netherlands (1989), attention was paid to ecotoxicological effects assessment. The proposed procedure was based on the advice of the Health Council of the Netherlands (1989) on risk assessment of toxic chemicals for ecosystems. The various extrapolation methods described by the Health Council are critically discussed in this paper. The extrapolation method of Van Straalen and Denneman (1989) is evaluated for eight chemicals and 11 aquatic species. Conclusions are drawn about the quality and quantity of the ecotoxicological data needed for aquatic effects assessment. For the soil—a compartment that is often at risk—ecotoxicological effects assessment is not possible because suitable ecotoxicological test methods still have to be developed.  相似文献   
225.
This article addresses the development of an agricultural productivity equation for predicting new soil (neo-sol) plant growth potential in Clay County, Minnesota, USA. Soil factors examined in the study include percent organic matter, percent slope, percent rock fragments, hydraulic conductivity, electrical conductivity, pH, topographic position, available water-holding capacity, bulk density, and percent clay. Squared terms and two-factor interaction terms were also examined as possible regressors. A best equation was selected that had a multiple coefficient of determination of 0.7399 and has five significant regressors and intercept withP.0001. The regressors are hydraulic conductivity, percent slope squared, bulk density times percent rock fragments, electrical conductivity times percent rock fragments, and electrical conductivity times percent organic matter. The regressors predict soil suitability for a general crop model. The crops included in the model are wheat, oats, barley, soybeans, sugar beets, sunflowers, and grasses/legumes.  相似文献   
226.
227.
The towns and cities of Saudi Arabia have been subjected to sustained growth pressures since the transformation of the country's economy following the discovery of oil in the Eastern Province of the Kingdom. The rapid growth which has been experienced has created major problems for the central and local government agencies responsible for planning and managing urban growth. The experience of Jeddah, one of the major cities in Saudi Arabia, is described and the problems of planning and managing its growth are analysed. Weaknesses relating to the structure of the planning system are identified, as are major difficulties in relation to the quality and quantity of professional staff. Recent attempts to improve the operation of the planning system are described and evaluated.  相似文献   
228.
ABSTRACT: Drought has been a prevalent feature of the American landscape during the latter part of the 1980s, producing serious socioeconomic and environmental consequences. These recent experiences with drought have renewed concern about the inadequacy of federal and state contingency planning efforts and the lack of coordination for assessment and response efforts between these levels of government. This paper presents the results of research aimed at facilitating the preparation of drought contingency plans by state government in conjunction with a state's overall water management planning activity. The ten-step drought plan development process reported is intended to improve mitigation efforts through more timely, effective, and efficient assessment and response activities. Officials in appropriate state agencies should examine the proposed framework and alter it to best address drought-related concerns, adding or deleting elements as necessary.  相似文献   
229.
本文主要论述了如下基本概念问题: 1、安全的主要经济功能是保障社会经济的增值和有效地减少事故的经济损失。本文试图构造增值函数I(S)和损失函数L(S)来描述其功能。 2、安全经济学的基本任务是研究安全的经济效益和安全的经济利益规律,使其有效地调整和协调安全与经济的关系,指导安全经济决策。 3、本文试提出发展安全经济学应遵循的三个基本原理。 4、为综合揭示安全经济规律,本文还探讨了安全经济的功能函数F(S)、成本函数C(S)、负担函数B(S)和效益函数E(S)。 5、针对实际应用,本文还提出了一种安全投资的评价方法及其优化理论。  相似文献   
230.
本文试用系统论、控制论和信息论的观点探索我国安全生产宏管理模式。文中主要分析了生产安全系统的内涵;行业生产安全系统的内涵;以及生产安全系统的宏观控制的内涵。并指出了行业生产安全系统是生产安全系统的主体控制系统,劳动安全监察系统是生产安全系统的强化控制系统。  相似文献   
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