Present status of the recycling of waste electrical and electronic equipment in Korea

In Korea due to rapid economical growth followed by urbanisation, breakage of large traditional families into small nuclear families, continuous changes in equipment features and capabilities causes tremendous increase in sale of new electrical and electronic equipment (EEE) and decrease in sale of used EEE. Subsequently, the ever-increasing quantity of waste electrical and electronic equipment (WEEE) has become a serious social problem and threat to the environment. Therefore, the gradual increase in the generation of WEEE intensifies the interest for recycling to conserve the resources and protect the environment. In view of the above, a review has been made related to the present status of the recycling of waste electrical and electronic equipment in Korea. This paper describes the present status of generation and recycling of waste electrical and electronic equipment, namely TVs, refrigerators, washing machines, air conditioners, personal computers and mobile phones in Korea. The commercial processes and the status of developing new technologies for the recycling of metallic values from waste printed circuit boards (PCBs) is also described briefly. Since 1998, three recycling centers are in full operation to recycle WEEE such as refrigerators, washing machines and air conditioners, having the total capacity of 880,000 units/year. All waste TVs are recently recycled on commission basis by several private recycling plants. The recycling of waste personal computers and mobile phones is insignificant in comparison with the amount of estimated obsolete those. Korea has adopted and enforced the extended producer responsibility (EPR) system. Korea is making consistent efforts to improve the recycling rate to the standards indicated in the EU directives for WEEE. Especially environmentally friendly and energy-saving technologies are being developed to recycle metal values from PCBs of WEEE.     

锅炉房电气设备运行安全应注意的几个问题

对工业锅炉房电气设备及电缆敷设的设计和运行管理安全提出应注意的问题,并提出本质安全要求。     

洗浴用小型锅炉的测试与评价

经过多次对煤炭气化高温蒸汽锅炉、型煤锅炉、常压反烧锅炉和蒸汽锅炉等洗浴用小锅炉的测试、分析与评价,确认煤炭气化高温蒸汽锅炉的节能环保指标都比其他锅炉具有显著的优越性。它可以在常压下产生150℃的高温蒸汽,燃烧散煤时其排放的SO2和烟尘都达到国家一级排放标准,锅炉平均热效率可达78.05%,比同吨位的常压热水锅炉和蒸汽锅炉节能30%,比型煤锅炉节能约50%,比燃油锅炉、燃气锅炉、电锅炉节能约60%以上。     

储罐长周期腐蚀声发射监测试验

对一放置2年时间的储罐试验模型进行长周期的声发射腐蚀监测,通过研究其在稳定腐蚀状态下的声发射信号特征,分析其腐蚀的机理和信号产生的原因,形成对储罐腐蚀更深入的认识。文章还对稳定腐蚀状态下的储罐声发射特征参数进行统计分析,为后续的储罐在线声发射检测评价打下数据基础。     

Spatial variability in soil water and salinity in Tamarix community in a semiarid saline region of the upper Yellow River北大核心CSCD

Tamarix is widely distributed in semiarid saline regions of the upper Yellow River. The community of Tamarix affects the spatial distribution of soil water and salinity. It is important to explore the dynamic response relationship of Tamarix community and spatial distribution of soil water and salinity in order to evaluate the effects of vegetation community construction and ecological restoration in this region. The natural Tamarix community in the secondary saline-alkali land of the Ningxia Yellow River Irrigation Area was investigated in July 2016. Classical statistics and geostatistics were used to analyze the spatial distribution characteristics of soil water and salinity. The results showed that the soil water content was relatively low (1.98%-7.55%), whereas the soil salinity was high (average conductivity 10.28-25.38 mS/cm) in the study area. The variability coefficient range of soil water and salinity was 36.1%-83.7%, both with moderate variations. Furthermore, the variation degree of soil salinity decreased with the increase in soil depth. The soil water and salinity had obvious spatial structure characteristics, which was mainly affected by structural factors or structural factors associated with stochastic factors. The coefficients of nugget were 0.04%-49.88%, indicating the strong spatial correlation. The spatial distribution of soil water and salinity in Tamarix community showed a patchy pattern; the soil water and salinity distribution in the areas with high Tamarix growing density were considerably high. The correlation analysis showed that there was a positive correlation between soil water and salinity in the study area. In conclusion, soil water and salinity restrict the distribution and growth of Tamarix. Furthermore, the distribution and growth of Tamarix enhanced the spatial variability of soil water and salinity. Keywords. © 2018 Science Press. All rights reserved.     

镉、汞、铅和石油烃复合污染对渤海湾常见渔业资源生物的影响初探(Effects of the Combined Pollution of Cd, Hg, Pb and Petroleum Hydrocarbons on Common Fishery Species in the Bohai Bay)

通过对1996～2005年渤海湾近岸海域海水镉、汞、铅和石油烃浓度变化的分析,发现海水中镉浓度呈明显上升趋势,汞、铅和石油烃则无明显变化趋势.加速生命试验法模型(Accelerated Life Testing model)的研究显示,1996～2005年渤海湾近岸海域海水镉、汞和铅平均浓度均已超过其对渤海湾常见渔业资源生物的安全浓度.镉、汞、铅和石油烃对生物的长期致死率鱼类分别为4.5%、16.3%、0.0%和12.0%,甲壳类为0.4%、7.9%、0.3%和6.6%,双壳类为10.5%、0.2%、0.2%和2.3%.效应加和模型(Independence Action model)的估算表明,在镉、汞、铅和石油烃组成的复合污染条件下,渤海湾常见鱼类、甲壳类和双壳类的长期死亡率分别为29.7%、14.6%和12.9%,其种群增长率分别降低约6.4%、14.6%和12.9%.与镉、汞、铅和石油烃单种污染物暴露相比,其复合污染导致的渤海湾常见渔业资源生物种群(鱼类、甲壳类和双壳类)增长率的降低更明显.因此,复合污染是导致渤海湾渔业资源衰退的重要因素。     

Theoretical and Experimental Investigation of a Novel Hybrid Heat-Pipe Solar Collector

Abstract

This article describes a novel flat plate heat-pipe solar collector, namely, the hybrid heat-pipe solar collector. An analytical model has been developed to calculate the collector efficiency as well as simulate the heat transfer processes occurring in the collector. The effects of heat pipes/absorber, top cover, flue gas channel geometry, and flue gas temperature and flow rate, on the collector efficiency were investigated based on three modes of operation, i.e., solar only operation, solar/exhaust gas combined, and solar, exhaust gas and boiler combined. Experimental testing of the collector was also carried out for each of these modes of operation under real climatic conditions. The results were used to estimate the efficiency of the collector and determine the relation between the efficiency and general external parameter. The modeling and experimental results were compared and a correlation factor was used to modify the theoretical predictions. It was found that the efficiency of the collector was increased by about 20–30% compared to a conventional flat-plate heat pipe solar collector.     

Effects of significant damage of flame gap surfaces in flameproof electrical apparatus on flame gap efficiency

Electrical apparatus for use in the presence of explosive gas atmospheres has to be specially designed to prevent the apparatus from igniting the gas. Flameproof design is one of several options, and one requirement is then that any holes and slits in the enclosure wall be designed to prevent a possible gas explosion inside the enclosure from being transmitted to an explosive gas cloud outside it. Current standards (IEC) require that joint surfaces have a surface roughness of <6.3 μm. Any damaged joint surface has be restored to this quality. The present investigation has demonstrated that flame gap surfaces in flameproof electrical apparatuses can suffer considerable mechanical and corrosive damage before the flame gaps no longer function satisfactorily. In some cases very significant mechanical surface damage in fact improves the gap performance. This indicates that current high costs of repairing and replacing flameproof electrical apparatus in process plants offshore and onshore can be reduced considerably without any increase of the explosion risk.     

LY12CZ铝合金腐蚀损伤的概率分布及其变化规律

采用铜加速乙酸盐雾试验方法对LY12CZ铝合金腐蚀行为进行了研究。结果表明：腐蚀深度服从Gumbel分布、正态分布、威布尔分布和对数正态4种分布。选用正态分布描述了LY12CZ铝合金在盐雾环境下的腐蚀损伤的分布特性,并得出了不同置信度和可靠度下腐蚀深度随时间变化的规律。     

电导和直流安培双检测器离子色谱法测定清洁水样中的碘化物

选用配备了2种不同检测器(电导检测器和直流安培检测器)的离子色谱仪对稀释后过0.22μm滤膜的水样进行分析。配备有直流安培检测器的离子色谱仪测定水中碘化物的方法在0.100~20.0μg/L范围内线性关系良好,相关系数(r)=0.9999,方法检出限为0.030μg/L,测定下限为0.120μg/L,样品加标回收率为95.0%~104%,相对标准偏差为1.06%~1.64%;配备有电导检测器的离子色谱仪测定水中碘化物的方法在20.0~2.00×105μg/L范围内线性关系良好,相关系数(r)=0.9995,方法检出限为2.00μg/L,测定下限为8.00μg/L,样品加标回收率为99.0%~110%,相对标准偏差为0.71%~3.12%。离子色谱-直流安培检测器法测定水中碘化物的方法准确度高、灵敏度高、精密度好,检出限相对较低,适用于测定ρ(碘化物)≤20.0μg/L的清洁水样;离子色谱-电导检测器法主要适用于测定ρ(碘化物)≥20.0μg/L的水样。