Graphical Presentation of 50/60 Hz Magnetic Field Contours as an Engineering Tool for Minimizing ELF Fields

Summary Since IARC classified ELF magnetic field as Possibly Carcinogenic to Human the fear from 50/60 Hz magnetic field exposure had been increased to the state of public “panic”. Subsequently, environment quality preservation organizations increased their pressure on their government to adopt the “precautionary principle” and to reduce the allowable ELF Magnetic Field exposure to much lower values than are recommended by ICNIRP-1998. As an example the present Environmental Ministry in Israel recommendation is to lower the ELF Field exposure to 10 mG averaged over 24 h. As a result of this stringent exposure guideline imposed by the government, electrical engineers who are involved in the deployment and installation of large and medium electrical utilities, such as overhead power lines, transformers, UPS systems, electrical public transportation, switching stations, etc., are much more aware to the need to employ special measures and methods for reducing the magnetic fields that might be emitted from such utilities. There are few computer codes that are capable of analyzing with great accuracy magnetic and electric fields surrounding single phase and three phase electrical utilities in a 3-D system. The best presentations of the analysis results are by equi-value contours depicting electric and magnetic fields. This graphical presentation is a powerful design tool that enables better deployment and installation design aided to reduce the magnetic field emissions from high-power electrical utilities. This paper describes the various types of graphical presentations available for ELF field contours, the dependent and independent variants and parameters, magnetic field animation for optimization of power line installation and routing, and finally an example that demonstrates the usefulness of the graphical presentation tools.     

地下金属矿山安全评价体系的探讨

对矿山实行安全评价是确保安全生产的重要措施。根据地下金属矿山生产工艺的特点，分析发生事故的原因及影响因素，以定量分析的方法，从企业管理、工程设计、人员配备、环境条件等方面进行安全评价，提出评价体系，系统而直观地反映企业生产安全程度。     

崩滑流雷达遥感应用潜力分析

综述了我国崩滑流（崩塌、滑坡、泥石流）遥感的应用现状；着重分析了成像雷达遥感在崩滑流识别、监测、预警中具有的独特优势，特别是随着新型成像雷达遥感（极化、干涉雷达）的发展，基于干涉雷达发展的差分干涉测量技术能以一量级甚至更小尺度测量地表形变，在崩滑流研究中能提供定量的动态信息，为崩滑流遥感应用研究注入了新的活力，开辟了新的思路；并指出以雷达（ＳＡＲ）遥感信息为主的多源信息复合解译，能为崩滑流灾害的调查提供更为方便、准确、及时、动态的信息．     

静电增强纤维层过滤技术的研究

对静电增强纤维层过滤进行理论及实验研究。得出纤维层在非稳态状态下,考虑三种作用机理时的效率式,并利用模型系统进行实验研究,对各种影响因素加以分析     

高电阻率收尘极板的实验研究

用电阻率较高的非金属材料制作电收尘器的收尘极板收尘,对于比电阻低于10~4Ω·cm的烟尘,能有效地克服积尘的跳跃式二次飞扬。对于比电阻为10~8Ω·cm左右的氧化铝粉尘,在工业现场实验,收尘效率达98.5％;对于比电阻为10~(13)Ω·cm左右的莹石粉尘,采用比电阻为10~(10)Ω·cm左右的混凝土极板,实验室实验,电晕电流正常,未观察到反电晕现象,推断存在“受抑制”的尘层间隙放电。     

三峡库区地质灾害监测数据采集与传输现状

文章对目前三峡库区地质灾害监测系统的构成进行了阐述,详细介绍了监测数据的采集和传输方式,并分析了每种方式的优缺点和改进办法,且对该类技术的发展趋势进行了预测。     

How are coastal households responding to climate change?

In Australia, shared responsibility is a concept advocated to promote collective climate change adaptation by multiple actors and institutions. However, a shared response is often promoted in the absence of information regarding actions currently taken; in particular, there is limited knowledge regarding action occurring at the household scale. To address this gap, we examine household actions taken to address climate change and associated hazards in two Australian coastal communities. Mixed methods research is conducted to answer three questions: (1) what actions are currently taken (mitigation, actions to lobby for change or adaptation to climate impacts)? (2) why are these actions taken (e.g. are they consistent with capacity, experience, perceptions of risk); and (3) what are the implications for adaptation? We find that households are predominantly mitigating greenhouse gas emissions and that impact orientated adaptive actions are limited. Coping strategies are considered sufficient to mange climate risks, proving a disincentive for additional adaptive action. Influencing factors differ, but generally, risk perception and climate change belief are associated with action. However, the likelihood of more action is a function of homeownership and a tendency to plan ahead. Addressing factors that support or constrain household adaptive decision-making and action, from the physical (e.g. homeownership) to the social (e.g. skills in planning and a culture of adapting to change) will be critical in increasing household participation in adaptation.     

Magnetophoretic separation of Chlorella sp.: Role of cationic polymer binder

Cationic polyelectrolyte promoted effective attachment of iron oxide nanoparticles (IONPs) onto microalgal cells through electrostatic attraction. Poly(diallyldimethylammonium chloride) (PDDA) and chitosan (ChiL), both are cationic polymer, are feasible to act as binding agent to promote rapid magnetophoretic separation of Chlorella sp. through low gradient magnetic separation (LGMS) with field gradient ▿B less than 80 T/m in real time. Cell separation efficiency up to 98% for the case of PDDA and 99% for the case of ChiL can be achieved in 6 min when 3 × 10⁷ cells/mL Chlorella sp. are exposed to 300 mg/L surface functionalized-IONPs (SF-IONPs). Different polyelectrolytes do not give significant effect on cell separation efficiency as long as the particle attachment occurred. However, the PDDA is more preferable as the binder for all type of microalgae medium than the chitosan (ChiL) since it is not pH dependent. SF-IONPs coated with PDDA guarantee the cell separation performance for all pH range of cell medium, with 98.21 ± 0.40% at pH 8.84. On the other hand, the ChiL performance will be affected by the cell medium pH, with only 22.93 ± 31.03% biomass recovery at pH 9.25.     

农业职业安全与健康分析研究

我国农业产业化经营已步入持续发展和提高的新阶段,农业生产维护中的安全与健康问题应给予更高的关注。本文对农业机械维护和基础设施维护中存在的风险与危害及其对健康的影响进行了描述与分析,提出了预防措施。     

基于层次-模糊评价法的山区油气管道地质灾害易发性研究

针对山区油气管道地质灾害的基本特征,将层次分析与模糊综合评价相结合,建立起可用于山区管道地质灾害易发性评价的层次-模糊评价模型;并从自然因素、管道敷设状况、灾害活动和设计与误操作四个方面建立山区油气管道地质灾害易发性评价体系.首先依据专家经验构造各层影响因素的判断矩阵,并利用层次分析法求出各影响因素的权重集,然后对山区油气管道地质灾害易发性进行多级模糊综合评价,最终根据评价结果确定山区油气管道地质灾害易发性等级.通过具体实例检验了本文所建立评价方法的应用效果.