非金属材料的氙灯曝露试验概述

氙灯曝露试验是非金属材料的耐候性和耐光性测试的主要方法之一,本文着重介绍了氙灯曝露试验的原理、试验条件在当前的氙灯曝露试验设备上的物理实现、主要的氙灯试验标准以及氙灯曝露试验应考虑的因素.     

聚苯乙烯材料的氙灯与海南自然老化的相关性和加速性研究

为考查聚苯乙烯材料(PS)的在人工和自然老化之间相关性和加速性,在海南湿热环境的5个站点开展自然暴露试验,基于色差变化数据,PS在琼海和临高的老化速率最大。通过开展3种不同条件的氙灯老化试验,比较自然和加速老化的相关性,选出最适合模拟海南湿热环境的氙灯试验条件。再对氙灯老化相对5个站点的自然老化的加速性进行了探讨,结果显示氙灯老化方法 1对海口自然老化的加速性最大,加速因子为7.87。     

关于长霉试验结果的再现性讨论

影响长霉试验结果再现性的因素众多。作者就菌种选用、试验操作与检测方法、试验设备三方面,探讨提高长霉试验结果再现性问题。     

汽车行业的氙灯曝露试验综述及技术发展趋势

本文着重对汽车行业主要的氙灯曝露试验标准的技术特点进行了综述,并分析了该行业氙灯曝露试验的技术发展趋势.     

振动环境试验中应注意问题分析

为了使振动试验具有高的再现性,试验的结果可信度高,防止因试验设备、人为操作失误而造成试验结果出现偏差。对振动试验中影响试验结果的因素进行了简要的说明,并对试验中应注意的问题进行了描述。     

连接器和继电器自然暴露和盐雾试验腐蚀效应分析

在热带海洋气候环境自然暴露试验站开展了连接器、继电器自然暴露棚下试验,同时实验室开展了模拟盐雾试验,获得了电连接器、继电器腐蚀效应试验结果。通过自然暴露试验与模拟试验的元器件腐蚀生成物形貌、成分和腐蚀机理对比分析,得出了自然暴露试验和模拟环境试验在腐蚀形貌和机理上的不同,为后续实验室模拟试验条件的制定提供参考,为器件的防腐蚀提供基础数据。     

电磁兼容测量结果可追溯性技术探讨

无线电波因其具有较强的方向性和反射性等传播特点,往往会引起电磁兼容测量结果的不稳定甚至有较大的偏差,如果不对测量过程中的测量和试验布置、试品的工况、记录报告等要素进行可追溯性分析和控制,势必会造成测量结果的随意和不确定性.因此在电磁兼容测量实验室,非常有必要对测量过程和测量结果进行可追溯性研究、分析和控制,一是提供准确可再现的测量数据,对客户负责,二是通过可追溯性控制,再现试验和测量过程,验证测量结果,对实验室的风险进行预见和预防.本文主要立求通过实际案例的分析,畅述和分析在电磁兼容测量实验室如何建立可追溯性的控制体系.     

《气候试验仪和大气暴露试验结果的比较》等10篇

《气候试验仪和大气暴露试验结果的比较》--《长野县林业综合センタ-业务报告》1999.(1998).84-85(日):对广告牌用的透明涂装木材,比较了用近似太阳光照射条件的气候试验仪进行的加速老化试验和大气暴露试验的结果.涂装预处理使用丙烯酸涂料,透明涂装使用丁二烯涂料.通过色差、光泽、接触角、涂膜缺陷率评价了老化,反映出了利用气候试验仪进行的加速老化和利用大气暴露进行的涂装耐候性的优劣,得知了大气暴露角度低则暴露环境变得严酷,加快老化,此时,耐候性差的预处理会受暴露角度的影响. 《以ISO为中心的老化评价试验技术》--《涂装技术》1999.38(10).102-105 (日):介绍了涂料/涂膜缺陷的评价及试验方法.对ISO中的主要相关标准及使用体会进行了阐述,还介绍了为使ISO标准更完善而进行的研讨状况. 《聚乙烯衬里钢管的彩色化》--《防锖防食技术发表大会讲演予稿集》1999.19th.107-110(日):题记钢管因其耐蚀性和长期耐久性而被广泛使用,考虑到美观问题还要求彩色化.最近已可以通过特殊预涂处理进行表面着色,因此使用各种涂料进行了附着性试验,以及利用户外曝露试验和盐雾试验进行了耐久性和耐候性的确认.试材的制作是利用粉末热粘砂法在钢板上进行聚乙烯衬里,将其表面分为3部分,各自经过预涂处理、砂纸机械粘砂、表面改性的基底处理,然后刷涂上6种涂料进行比较.特殊预涂处理获得了良好的结果.举出了根据上述结果而制作的4个实用例. 《臭氧对涂膜耐久性变化的影响》--《材料と环境讨论会讲演集》 1999.46th.379-382(日): 为了掌握臭氧对涂膜耐久性的影响, 把各种防腐蚀涂膜暴露在高浓度的臭氧环境中, 与紫外线照射、连续盐水喷雾进行了比较. 结果发现臭氧不但影响涂膜表面性能, 而且对涂膜内部的性能也有影响. 在实际环境中臭氧和紫外线对涂膜的影响比例约为0.3∶1. 在臭氧等氧化性成分多的环境中, 不能无视臭氧对涂膜性能的影响. 《具有光稳定化结构的高耐候性预涂钢板的耐蚀性》--《材料とプロセス》1999.12(6).1351(日): 调查了涂膜不因太阳光而老化厉害的题记钢板的耐蚀性.使用经铬酸盐光泽处理过的热浸镀锌钢板,制作出加入了耐候性好的光稳定剂HALS的丙烯酸涂料预涂钢板,通过耐候性试验及循环腐蚀试验与一般聚酯涂料钢板进行了比较,结果得知在耐候性试验和循环腐蚀试验中,题记钢板的耐蚀性比一般预涂钢板要好. 《新的铝电泳涂装复合被膜的耐候性》--《アルミニウム研究会志》1999.(6).10-17(日):介绍新的灰色无光漆电泳涂装复合被膜,并基于加速耐候性试验和大气暴露试验结果评价了其耐候性. 《利用交流阻抗法进行粉末涂装钢板的耐久性评价》--《表面技术协会讲演大会讲演要旨集》1999.100th.238-239(日):使用交流阻抗法开发了快速评价粉末涂装钢板耐蚀性的方法.在加速耐候性试验后和户外暴露试验后研讨了涂膜种类(树脂、颜料)对涂装耐久性的影响.从加速耐候性试验后涂膜电阻的时效变化中明确得知了涂膜种类对供试材耐久性的影响,确认了水分是涂膜老化的重要因素.而在户外暴露试验后,没有看到涂膜种类对涂膜电阻的影响. 《有关钢制烟囱涂装修改技术的研究》--《日本建筑学会学术讲演梗概集A-1材料施工》1999.619-620(日):对具有延伸性的涂装规格进行了180天加速腐蚀试验,评价了其防锈性能.试验体是以钢板作基材,通过户外暴露使之腐蚀,按涂料厂家的标准规格用毛刷涂装至中涂层,再使用硬化了的试验体进行180天复合循环试验,评价了生锈的状况.另外,测量了涂膜的交流阻抗,比较了防锈性能,同时在冲压加工部位评价了对钢材变形的随着性. 《有关寒冷地带防蚀涂装耐久性的研究》--《土木学会论文集》1999.(630).11-25(日):根据暴露试验和实桥试验,评价了冰海用涂料和新的寒冷地带用重防蚀涂料等超厚膜型涂装系的性能.从10年暴露试验,8年实桥试验结果得知:以富锌漆作底漆,使用了环氧+聚氨脂或氟树脂涂料的涂装系防蚀性良好;超厚膜型涂装系如果使用耐候性好的面涂涂料的话则也可以用作重防蚀涂装系;而邻苯二甲酸、氯化橡胶系涂料早期会产生裂纹、剥落等,不适宜作寒冷地带用涂料. 《考虑了景观性的重防蚀被覆材料的长期耐久性》--《防锖管理》2000(3).103-106(日):对用于景观设计的着色重防蚀被覆材料进行了加速试验及5年大气暴露试验,调查了其长期耐久性.结果得知聚乙烯因老化防止剂和颜料,聚氨酯因颜料而受到较大影响. (广州电器科学研究所)     

汽车内外饰件氙灯老化试验对样品的要求

氙灯老化试验目前是众多汽车企业必检项目之一,汽车内外饰件用到的非金属材料有很多,如涂料、塑料、纤维织物、橡胶、皮革及装饰木纹件等等,并且形状多样,如何让氙灯试验更加准确,重复性更好,这对试验样品有严格的要求。     

环境与可靠性试验方法研究

实验室进行的试验分两类,一类通过应力激发观察发现事物的运动规律与特性达到科学发现的目的;第二类是通过环境可能遇到各种事件,用事件模拟的方法,考核评定产品耐环境的能力,观测某种环境应力的作用产生的效应,发现产品缺陷和薄弱环节,改进产品设计工艺,提高产品的质量可得到科学快速正确试验结果,各类试验都制定了统一试验方法,确保试验的模拟性和试验结果再现性。随科学技术的发展试验方法也在发展,有关组织规定定期修订标准,以确保试验方法的不断发展,本文讨论试验方法中的发展。     

实验室电磁骚扰测量结果复现性保障

电磁兼容测量结果与测量过程具有较强的相关性和较差的复现性。对一个电磁兼容实验室怎么在极其复杂的电磁骚扰测量中保证测量结果的准确性和可信性？文章重点从管理、设备、人员和技术等方面分析了如何建立一个全方位的可追溯性的保证体系，并严格贯彻实施，从而使实验室电磁骚扰测量结果复现性得到保障。     

UNIVARLATE LEAST SQUARES MUSKINGUM FLOOD ROUTING1

ABSTRACT: The Muskingum method of hydrologic flood routing is based on a graphical bivariate curve fitting procedure. The subjectivity of this procedure may lead to problems of reproducibility and provides no guarantee of model coefficients which minimize the error of estimation. A transformation is developed to express the Muskingum method as a univariate transcendental function suitable for numeric solution. Solution of this function minimizes the sum of the squared deviations between estimated and measured rates of discharge. Five textbook examples of the Muskingum method are evaluated by the univariate transformation. Error reductions range from negligible to tenfold. While the univariate transformation may not improve upon graphically-based results in every case, in no instances are the univariate results inferior; in many cases they are superior.     

Specific Contributions of Politics,Economics, and Toxicology in Setting Socially Consensual Limit Values

/ Limit values are legal limits for the concentrations of substances in the environment. They must be agreed upon in a consensual procedure between science, economics/technology, and political forces. This is a crucial political precondition for their social acceptance. The arguments put forward to justify their expediency and numerical level are based not only on risk-benefit considerations but also on the aspect of the technical avoidability of direct and indirect exposure. The critical assessment of the direct benefit of specified exposures falls within the responsibility of economics/technology, whereas criteria for their potential adverse effects (direct and indirect) are provided by medicine/biochemistry and/or ecology. Within this concept, the avoidance of nonbeneficial-even if not openly adverse-exposure is the essential aim of environmental hygiene and should be promoted by politics/science. In general, society or segments thereof reject adverse, accept beneficial, and tolerate unavoidable exposure. Conflicts of interest arise when different groups of society simultaneously define a given exposure as being adverse, beneficial, and unavoidable. Therefore, from the viewpoint of society as a whole, an optimal exposure lies as far as reasonably achievable at a level lower than known or plausible adverse effect thresholds (as defined by toxicology or ecology). This optimal level of exposure must be determined using a transparent and, hence, public procedure.KEY WORDS: Legal limit values; Benefit threshold; Social acceptance; Social tolerability; Adverse effect threshold; Avoidable exposure; Tolerance threshold; Environmental hygiene     

The relation between objective and subjective exposure to traffic noise around two suburban highway viaducts in Ghent: lessons for urban environmental policy

A growing empirical evidence base identifies environmental noise exposure as an important health problem. While the health effects depend for a great part on personal noise sensitivity and contextual factors, in environmental policy, generic noise standards and procedures based on objective sound levels are used. In this article, the relation between objective and subjective noise exposure variables is further explored by carrying out a residents’ survey in a highly noise polluted area along two highways south of the city centre of Ghent, Belgium. The survey results show only a weak correlation between objective and subjective exposure variables, with both variables demonstrating different associations with the respondents’ background characteristics. While lower-educated and lower-income people are generally higher exposed according to the models, they do not report a higher subjective exposure. People who have been living longer in the area are not necessarily higher exposed according to the models but do report a higher subjective exposure. Most strikingly, owners of a comfortable detached house report a higher subjective exposure than renters of an apartment or small house, while the latter group is significantly higher exposed according to the models. The results support a plea for the joint evaluation of both objective and subjective noise exposure variables in environmental policy and environmental assessments. In addition, the results argue for specific attention for noise exposure of socio-economically vulnerable people and the establishment of a shared knowledge base on noise exposure with both objective and subjective information.     

USE OF HEMISPHERIC IMAGERY FOR ESTIMATING STREAM SOLAR EXPOSURE1

ABSTRACT: Solar exposure profoundly affects stream processes and species composition. Despite this, prominent stream monitoring protocols focus on canopy closure (obstruction of the sky as a whole) rather than on measures of solar exposure or shading. We identify a candidate set of solar exposure metrics that can be derived from hemispheric images. These metrics enable a more mechanistic evaluation of solar exposure than can be achieved with canopy closure metrics. Data collected from 31 stream reaches in eastern Oregon enable us to quantify and compare metrics of solar exposure from hemispheric images and a metric of canopy closure with a concave densiometer. Repeatability of hemispheric metrics is generally as good as or better than the densiometer closure metric, and variation in the analysis of hemispheric images attributable to differences between analysts is negligibly small. Metrics from the hemispheric images and the densiometer are typically strongly correlated, at the scale of an individual observation and for 150 m stream reaches, but not always in a linear fashion. We quantify the character of the uncertainty in the relationship between the densiometer and the hemispheric metrics. Hemispheric imagery produces repeatable metrics representing an important ecological attribute; thus those researching the effects of solar exposure on stream ecosystems should consider the use of hemispheric imagery.     

Social Dimensions of Urban Flood Experience,Exposure, and Concern

With growing urban populations and climate change, urban flooding is an important global issue, even in dryland regions. Flood risk assessments are usually used to identify vulnerable locations and populations, flooding experience patterns, or levels of concern about flooding, but rarely are all of these approaches combined. Furthermore, the social dynamics of flood concerns, exposure, and experience are underexplored. We combined geographic and survey data on household‐level measures of flood experience, concern, and exposure in Utah's urbanizing Wasatch Front. We asked: (1) Are socially vulnerable groups more likely to be exposed to flood risk? (2) How common are flooding experiences among urban residents, and how are these experiences related to sociodemographic characteristics and exposure? and (3) How concerned are urban residents about flooding, and does concern vary by exposure, flood experience, and sociodemographic characteristics? Although floodplain residents were more likely to be White and have higher incomes, respondents who were of a racial/ethnic minority, were older, had less education, and were living in floodplains were more likely to report flood experiences and concern about flooding. Flood risk management approaches need to address social as well as physical sources of vulnerability to floods and recognize social sources of variation in flood experiences and concern.     

On experimental setup in bioelectromagnetics

Bioeffects created by electromagnetic field (EMF) are the subject of intensive studies. This paper critically considers estimations of exposure to EMF in bioelectromagnetic experiments. Results of calculations presented herein show the significant role of the presence of conducting bodies (the exposure system) near an object under test on EMF energy absorption as well as mutual interactions between simultaneously exposed objects. Our aims herein are twofold: firstly to find a way to refer measurement results to free-space conditions in order to enable comparison of results obtained in different laboratories, and secondly to show that EMF energy absorption in any exposed object is different and that this difference is a function of the size of the exposure system, the number of exposed objects, and the particular properties (i.e., the electromagnetic structure) of the objects. In the authors’ opinion the existence of interactions caused by the presence of the exposure system and other exposed objects is a reason why remarkable differences are observed between experiments performed even under supposedly identical conditions. The presented considerations and conclusion suggest wider participation of physicists and engineers in bioelectromagnetic experiments in order to ensure the correctness of metrological aspects of these experiments.     

EMF risk for operators mounting,adjusting and maintaining base stations

In the recent years concerns whether exposure to electromagnetic fields (EMF) from base station antennae can cause adverse health effects are grown. Great attention is paid on risk of EMF exposure to people living in a close proximity of base stations. In this issue, a point of interest is the personnel mounting, adjusting and maintaining base stations. Their working tasks require stay in high EMF levels’ conditions. There are only few studies concerning this specific occupational group. The results from our previous investigation (COST 281—Graz, 2006) show that in many cases on performing some specific tasks operators are overexposed according to our national legislation, and ICNIRP guidelines. Here, we present an extended study covering more base stations and more precise scenario for performed tasks and working positions. Results of exposure assessment are presented. They include energetic load calculations on the basis of Bulgarian national legislation, and the corresponding SAR values. Data are used to determine permissible time duration for each particular work operation and served as a base for limiting the exposure and proposal for protective measures for the personnel.     

Needs of communications with general public about the potential risk of electromagnetic fields and methods for achieving this goal

In the recent years concerns whether exposure to electromagnetic fields (EMF) from base station antennae can cause adverse health effects are grown. Great attention is paid on risk of EMF exposure to people living in a close proximity of base stations. In this issue, a point of interest is the personnel mounting, adjusting and maintaining base stations. Their working tasks require stay in high EMF levels’ conditions. There are only few studies concerning this specific occupational group. The results from our previous investigation (Zaryabova and Israel 2006) show that in␣many cases on performing some specific tasks operators are overexposed according to our national legislation, and ICNIRP guidelines. Here, we present an extended study covering more base stations and more precise scenario for performed tasks and working positions. Results of exposure assessment are presented. They include energetic load calculations on the basis of Bulgarian national legislation, and the corresponding SAR values. Data are used to determine permissible time duration for each particular work operation and served as a base for limiting the exposure and proposal for protective measures for the personnel.     

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.