Influence of thermal environment on metallographic structure characteristics of the electric arc bead pattern

Electrical apparatuses are prone to arc, which generally causes a fire, even an explosion hazard, when a flammable gas mixture is present, especially during industrial processes. Terrible fire scenes are challenging for fire investigations. In this work, by performing a simultaneous thermal analysis test we simulated a fire environment and found that as the oxygen concentration decreased, the oxidation/exothermic peak temperature of ‘cause’ bead became higher, but the melting temperature was unaffected. Results indicated that the bead pattern underwent oxidation at approximately 831 °C, melting initiated at approximately 1060 °C, and the pattern then disappeared. The melted pattern grain changes were divided into three critical temperature stages: Approximately 600 °C, the onset temperature at which the melted pattern grains began to be equiaxed; approximately 831 °C, at which the grains were interspersed with oxygen-containing material; and 831–1060 °C, when the grains disappeared, which is a criterion for identifying electrical fires. However, the boundaries remained throughout the thermal environment process. Moreover, the bead pattern demonstrated three metallographic regions: Deep layer (Region I), the intermediate layer (Region Ⅱ), and surface layer (Region Ⅲ). Region I was the most thermally sensitive, in which equiaxed crystals first appeared. Region Ⅲ was the thermal reaction lag zone, in which the typical branching crystals finally disappeared, and Region Ⅱ was intermediate between Regions I and Ⅲ. The results may help fire investigators determine the fire scene temperature stages and provide support for fire evidence extraction.     

漏电开关质量可靠性评价指标及模型的探讨——兼论民用建筑安全供用电网络的可靠构筑

结合对电气可靠性技术的宏观分析态势及安全减灾[9][10]的迫切要求,研究了实用的漏电开关质量可靠性评价指标及分析模型;针对漏电开关的故障,提出了构筑现代民用建筑(多指住宅)供用电安全网络的实施要点及有关标准化措施。     

对Ag—DDC光度法测砷的分析

用Ａｇ－ＤＤＣ光度法测砷时，影响测定结果的准确度因素较多．本文重点阐述影响原因及其解决办法．     

Nitrate removal from aqueous solutions by magnetic cationic hydrogel: Effect of electrostatic adsorption and mechanism

Excessive nitrate(NO_3~-) is among the most problematic surface water and groundwater pollutants.In this study,a type of magnetic cationic hydrogel(MCH) is employed for NO_3~-adsorption and well characterized herein.Its adsorption capacity is considerably pHdependent and achieves the optimal adsorption(maximum NO_3~--adsorption capacity is95.88±1.24 mg/g) when the pH level is 5.2-8.8.The fitting result using the homogeneous surface diffusion model indicates that the surface/film diffusion controls the adsorption rate,and NO_3~-approaches the center of MCH particles within 30 min.The diffusion coefficient(D_s) and external mass transfer coefficient(k_F) in the liquid phase are1.15 × 10~(-6) cm~2/min and 4.5 × 10~(-6) cm/min,respectively.The MCH is employed to treat surface water that contains 10 mg/L of NO_3~-,and it is found that the optimal magnetic separation time is 1.6 min.The high-efficiency mass transfer and magnetic separation of MCH during the adsorption-regeneration process favors its application in surface water treatment.Furthermore,the study of the mechanism involved reveals that both-N~+(CH_3)_3 groups and NO_3~-are convoluted in adsorption via electrostatic interactions.It is further found that ion exchange between NO_3~-and chlorine occurs.     

厚壁管变形横波周向超声检测工艺及缺陷定位系统开发

在理论研究的基础上，利用试块对厚壁管变型横波与折射横波检测灵敏度进行了比较，证实了变型横波在厚壁管件中的检测灵敏度高于折射横波；设计开发计算软件，实现缺陷进行自动定位，大大提高现场检测效率和定位精度。     

涡流检波器建模研究及参数识别

笔者分析了涡流检波器的工作原理 :综合考虑了检波器磁路系统中 ,外壳、磁靴等部件的电磁感应对固定线圈感应电流的影响 ;建立了七参数的动力学模型。理论分析表明 :涡流检波器的外壳系统的附加耦合效应 ,影响了检波器的频率特性。在上述分析和研究的基础上 ,设计了检波器参数识别实验系统 ;验证了七参数动力学模型的合理性 ;研究的结论为检波器结构设计中改善和控制其特性参数、提高其工作安全可靠性等 ,提供了理论依据。     

废弃电池能否进入废弃电器电子产品处理目录(第二批)管理的筛选评估分析

2009年2月,国务院发布《废弃电器电子产品回收处理管理条例》,成为我国废弃电器电子产品回收处理的纲领性文件。在《废弃电器电子产品处理目录(第一批)》中,明确将电视机、电冰箱、洗衣机、房间空调器、微型计算机等5种产品纳入第一批目录。同时,为了为了能够及时、客观地与经济发展、技术进步以及电器电子产品行业的发展变化等相适应,《目录》管理委员会起草了《制订和调整废弃电器电子产品处理目录的若干规定》,明确随着经济发展变化及电子产品废弃形势调整电器电子产品处理目录的原则。废弃电池在近几年来在我国增长速度很大,将来的管理形势十分紧迫。本文在此分析我国几种废弃电池(铅酸电池、镍氢电池及锂电池)的产生量、再生处理处置情况及管理政策导向。并在目录一批筛选原则的基础上利用权重分析法,筛选评估废弃电池能否进入废弃电器电子产品处理目录(第二批)管理的可能,研究显示铅酸电池已具备进入管理目录的资质。     

Drink driving deterrents and self-reported offending behaviours among a sample of Queensland motorists

Problem

The efficacy of drink driving (driving under the influence, DUI) countermeasures to deter motorists from driving over the legal limit is extremely important when considering the personal and economic impact the offending behavior has on the community. This paper reports on an examination of 780 Queensland motorists' perceptions of legal and non-legal sanctions and their deterrent impact on self-reported offending behavior. Method: The data were collected via a telephone survey of motorists recruited from a random sample of all listed telephone numbers in the state, adjusted according to district population figures. Results: The results indicated that there were a range of legal and non-legal factors that were significantly associated with self-reported DUI including: the perceived risk of apprehension and license loss (legal factors); and concerns relating to the possibility of being involved in a crash and hurting another person (non-legal factors). However, additional multivariate analyses indicated that while both legal and non-legal factors significantly predicted self-reported DUI, higher alcohol consumption levels and more favorable attitudes to the behavior also appear to increase the likelihood of DUI. Discussion: The paper will outline the direct implications of the research project such as the development and promotion of countermeasures that both effectively deter motorists and address pro-offending attitudes. Impact on industry: The findings also highlight that DUI remains a relatively common behaviour among some motoring groups and that there is a need to extend current levels of enforcement as well as adopt innovative strategies to enhance the impact of these operations on the offending behaviour.     

Measurement of selected indoor physical environmental factors in hairdresser salons in a Turkish City

Objectives The purpose of this study was to determine electromagnetic fields, electric fields, humidity, temperature, and illumination levels in hairdresser salons located in the downtown area of Aydin, Turkey. Also some health problems which could be related with the occupational factors are evaluated. Materials and methods The study was carried out in 30 hairdresser salons, all of which had been registered within the past 5 years. Electric and electromagnetic fields, illumination, temperature and humidity measurements were determined for hairdryers, hood hairdryers and depilatory heaters in the participating salons. A brief questionnaire about characteristics and the health status of hairdressers and workplace conditions was prepared and administered to the hairdressers at the salons. Results The mean electric fields of hairdryers, hood hairdryers and depilatory heaters were determined as 518 ± 74, 1,123 ± 199, and 648 ± 146 in V/m, respectively, at 5 cm from the surface of each device. These appliances generate mean electromagnetic fields in excess of 0.25 μT at 5 cm: hand-held hairdryers, 5.0 ± 0.7 μT; hood hairdryers, 1.6 ± 0.3 μT; and depilatory heaters 1.9 ± 0.6 μT. Total average of cumulative electric and electromagnetic fields, measured at a distance of 90 cm from the surface of these three devices was calculated to be 98.8 V/m and 0.5 μT, in the participating salons. Conclusions This preliminary study suggests that physical environmental factors in the salons may be contributing to the health problems of the hairdressers, and the electrical equipments in the workplaces may have cumulative electric and electromagnetic effects.     

Integrated testing and intelligent assessment—new challenges under REACH

BACKGROUND, AIM AND SCOPE: Due to a number of drawbacks associated with the previous regime for the assessment of new and existing chemicals, the European Union established a new regulation concerning the registration, evaluation, authorisation and restriction of chemicals (REACH). All relevant industrial chemicals must now be assessed. Instead of the authorities, industry itself is responsible for the risk assessment. To achieve better and more efficient assessments while reducing animal testing, all information-standard, non-standard and non-testing-has to be used in an integrated manner. To meet these challenges, the current technical guidance documents for risk assessment of new and existing chemicals had to be updated and extended considerably. This was done by experts in a number of REACH Implementation Projects. This paper presents the most relevant results of the expert Endpoint Working Group on Aquatic Toxicity in order to illustrate the change of paradigm in the future assessment of hazards to the aquatic environment by chemical substances. MAIN FEATURES AND CHALLENGES: REACH sets certain minimum data requirements in order to achieve a high level of protection for human health and the environment. It encourages the assessor to use alternative information instead of or in addition to standard one. This information has to be equivalent to the standard information requirement and adequate to draw overall conclusions with respect to the regulatory endpoints classification and labelling, persistent, bioaccumulative and toxic (PBT) assessment and predicted no-effect concentrations (PNEC) derivation. The main task of the expert working group was to develop guidance on how to evaluate the toxicity of a substance based on integration of information from different sources and of various degrees of uncertainty in a weight of evidence approach. INTEGRATED TESTING AND INTELLIGENT ASSESSMENT: In order to verify the equivalence and adequacy of different types of information, a flexible sequence of steps was proposed, covering characterisation of the substance, analysis of modes of action, identification of possible analogues, evaluation of existing in vivo and in vitro testing data as well as of QSAR results. Finally, all available data from the different steps have to be integrated to come to an overall conclusion on the toxicity of the substance. This weight of evidence approach is the basis for the development of integrated testing strategies (ITS), in that the available evidence can help to determine subsequent testing steps and is essential for an optimal assessment. Its flexibility helps to meet the different requirements for drawing conclusions on the endpoints classification and labelling, PNEC derivation as well as PBT assessment. The integration of all kinds of additional information in a multi-criteria assessment reduces the uncertainties involved with extrapolation to the ecosystem level. The weight of evidence approach is illustrated by practical examples. CONCLUSIONS AND PERSPECTIVES: REACH leads to higher challenges in order to make sound decisions with fewer resources, i.e. to move away from extensive standard testing to an intelligent substance-tailored approach. Expert judgement and integrated thinking are key elements of the weight of evidence concept and ITS, potentially leading to better risk assessments. Important sub-lethal effects such as endocrine disruption, which are not covered by the current procedure, can be considered. Conclusions have to be fully substantiated: Risk communication will be an important aspect of future assessments.