走向工作面贯通上山与支架快速回撤技术

针对走向工作面停采线与上山之间的护巷煤柱造成煤炭损失，支架回撤工艺复杂、巷道掘进量大等问题，提出走向工作面贯通上山与支架快速回撤技术。工作面贯通采区上山，利用上山回撤支架。在贯通前，利用压力拱模型分析剩余煤柱应力变化规律，并结合极限平衡区公式，确定让压煤柱为8 m；对贯通前基本顶合理断裂位置、让压调节机制、末采阶段采高进行了分析确定，并采取上山巷内补强支护及挂绳铺网措施。贯通上山后，首先利用支架对上山留巷，完成留巷后，利用上山回撤支架，先将上部端头3架逆时针旋转90°作为掩护架，在对剩余支架逐架回撤时，3个掩护架呈现台阶型。提出的技术取消了护巷煤柱及回撤通道，提高了煤炭采出率，减少了巷道掘进量，简化了回撤工艺。     

A product analysis-based study on the mechanism of inflammable gas explosion suppression

To study the mechanism of the suppressing effect of Expanded Aluminium (EA) on the premixed gas explosion, premixed methane-air and propane-air gases were undergone explosion reaction in the presence of EA in a self-designed closed pipeline with the overpressures and the compositions, rates and sensitivities of products analyzed. The results showed that the 9.5% methane-air and 5% propane-air explosions produced peak pressures decreased by 79.3% and 65.6%, and residual methane and propane contents increased by 270% and 560% respectively than without EA. In addition, the results revealed that the explosions of propane in the presence of EA produced less methane and carbon oxides contents, but more ethylene and propylene contents. The simulation showed that H, O, and OH are the key factors affecting the rate of products. The product compositions, together with other parameters, suggested that EA decreased temperature, inhibited chain initiation and propagation reaction, but facilitated chain termination reaction by advancing and accelerating the gas phase and wall destruction reaction of radicals, especially collisions and concentration of key free radicals. This new research method based on the analysis of explosion products can be used for in-depth research into gas explosion features and shed light on the suppressing mechanism of EA in flammable gas explosion.     

Arsenic residue in residential area after cleanup of pesticide illegal dumping sources in Thanh Hoa province,Central Vietnam

In Vietnam, Nicotex's site is perhaps the most infamous case of illegal disposal of toxic pesticides near residential areas. In 2013, affected villagers discovered illegal burials of around 1,000 tons of expired pesticides in the Nicotex factory. Organic pesticides were detected in illegal burial areas (IBAs) around 60 times greater than acceptable levels, but no attention was paid to contamination of metals, metalloids, and other classes of organic contaminants, which could be co-contaminants in pesticide formulation. This study assessed the contaminants remaining in the IBAs and surrounding residential areas two years after the source removal conducted in 2014. Additionally, a preliminary health risk assessment from residual contaminants was performed. Nine classes of chemicals including parental pesticides, inorganic and organic degradation byproducts, and metals and metalloids, comprising 123 chemicals were quantified in soil, sediment, and water samples from Nicotex and surrounding residential areas. Although concentrations of organic pesticides were below acceptable levels, arsenic contamination in the soil in a Nicotex IBA named NCT5 and Nap village (NV) exceeded the acceptable level. The enrichment factor and log-probability plot indicate that arsenic enrichment at NV is not from natural sources but is associated with arsenic contamination in NCT5. Arsenic may be a co-contaminant in pesticide manufacturing or an arsenical pesticide, such as monosodium methanearsonate. Arsenic found in NV was toxic arsenate for which the preliminary risk assessment yielded an unacceptable excess carcinogenic risk (1 × 10^?4). While all attention was paid to investigate and treat contamination of organic pesticides, it turns out that arsenic is the major existing threat which poses an unacceptable cancer risk in good agreement with the high cancer rate claimed by villagers near Nicotex. This justifies the need for further investigation of the extent of the arsenic contamination and restoration of the contaminated land.     

Validation of the Polish version of the World Health Organization Disability Assessment Schedule (WHODAS 2.0) in an elderly population (60–70 years old)

Purpose. To assess the reliability and validity of the Polish version of the 36-point World Health Organization Disability Assessment Schedule (WHODAS 2.0) in an elderly population. Method. One thousand randomly selected individuals, aged 60–70 years, living in south-eastern Poland were assessed using the Polish version of the WHODAS 2.0. Results. The analysis confirmed the high reliability and validity of the tool. Cronbach’s α index was 0.89. The tool had high stability, and the correlation between test and retest results was high. The relevance of the domain selection was high or very high. A factor analysis confirmed the relevance of assigning questions to domains. High theoretical relevance was also demonstrated. Statistically significant differences between those who were and were not suffering from health problems were observed. An analysis of the internal structure of the WHODAS 2.0 revealed strong correlations between the components of each domain and the final result. Conclusion. The Polish version of the WHODAS 2.0 showed high reliability and validity; thus, it can be used to assess health, functioning and disability in the elderly population of Poland.     

基于SVM的矿井通风阻力系数影响因素分析与预测

矿井通风阻力系数是通风安全最重要的基础参数之一，为了实现矿井通风阻力系数简单准确地预测，提出了利用支持向量机（SVM）来预测矿井通风阻力系数的方法。通过分析影响因子与矿井通风阻力系数的相关性关系，并利用MATLAB逐步建立单影响因素与矿井通风阻力系数、多影响因素与矿井通风阻力系数之间的SVM预测模型，对比分析各预测模型的相对误差，确定最佳矿井通风阻力系数预测模型，即当输入模型影响因素为巷道断面积、周长和支护方式时，预测相对误差小于10%的样本数占测试样本的76%，相对误差小于20%的样本数占测试样本的90%。结果表明:该预测方法在矿井通风阻力系数预测中是可行的，并具较高的准确性。     

我国污染物总量控制制度改革的思考

污染物总量控制制度是我国环境保护制度的重要组成部分。结合污染物总量控制制度的实施现状,分析实施过程中减排基数、核算体系、责任主体等方面存在的问题。提出,改革现行污染物总量控制制度,将总量控制与改革中的排污许可制相融合,落实企业主体责任,将总量指标与环境质量改善挂钩,建立差异化的减排核算体系,并加强日常监管,达到改善环境质量的目标。     

600 MW机组低压转子叶片裂纹分析

针对某台600 MW亚临界参数汽轮机低压转子的末三级叶片(2Cr12NiMo1W1V钢)出汽侧裂纹进行了宏观形貌观察、化学成分分析、金相组织分析、室温冲击韧性试验、硬度试验，并对断口进行了扫描电镜及能谱分析。结果表明：此次开裂的低压转子叶片，是由于其化学成分Mo元素含量低于标准要求，导致材料的KISCC降低，以及硬度偏低造成裂纹扩展所需的外界启动应力降低，进而在运行过程中拉应力和湿蒸汽的氧化腐蚀共同作用下，发生了应力腐蚀开裂。     

宁波市“十二五”与“十一五”期间酸雨污染特征变化趋势分析

基于地面观测数据,分析了"十一五"和"十二五"期间宁波市酸雨污染特征变化趋势。结果表明,2015年降水pH从2010年的4.37上升到4.89;2010—2015年酸雨发生频率降低了17.4百分点;重酸雨区范围不断缩小,轻酸雨区范围不断扩大,酸雨污染程度有所改善。降水中化学组成变化显示,与"十一五"末相比,2015年除NO_3~-、Cl~-外其他离子浓度均有所下降;2015年SO_3~(2-)与NO_3~-的当量浓度之比从2010年的3.10下降到1.73,表明酸雨污染从硫酸型向硫酸与硝酸混合型转变。     

沼泽湿地水生无脊椎动物完整性指数构建与健康评价

依据2017年5、7、9月对三江平原19处沼泽湿地(参照湿地6处,受损湿地13处)的水生无脊椎动物采样结果,应用生物完整性理论和方法,构建水生无脊椎动物完整性指数,评价三江平原沼泽湿地健康状况。通过对27个候选指标的分布范围、判别能力和相关性分析,筛选出总分类单元数、扁卷螺科百分比、龙虱科百分比、刮食者百分比4个指标构成水生无脊椎动物完整性指数核心指标。采用比值法计算各指标参数值,将各参数值加和得到水生无脊椎动物完整性指数值。根据参照湿地水生无脊椎动物完整性指数值的25%分位数值确定评价标准,对小于25%分位数的值进行三等分,确定三江平原沼泽湿地健康评价标准:≥2.58,无干扰;1.72～2.58,轻度干扰;0.86～1.72,中度干扰;0～0.86,重度干扰。结果表明:所调查的三江平原沼泽湿地有78.95%受到不同程度的干扰(其中47.37%受到了中重度干扰),21.05%属于无干扰。     

考虑保护层响应的炼化过程系统风险动态转移模型

为适时、有效地控制炼化过程系统风险,以模糊Petri网(FPN)为基础,针对炼化系统动态退化性和系统中保护层对风险转移的干预性,建立考虑保护层响应的炼化过程系统风险动态转移模型。描述基于FPN的保护层作用动态机制,分析炼化系统在保护层干预下,从非正常干扰触发开始至炼化系统退化过程的风险变化趋势。最后通过正己烷缓冲罐案例分析验证模型。结果表明:正己烷缓冲罐在开始运行的30 000 h内,系统风险等级呈阶段性变化,在工作的前16 800 h,风险为Ⅰ级;第16 800~27 600 h,风险为Ⅱ级;第27 600~30 000 h,风险为Ⅲ级。