公路工程施工安全事故致因模型构建

为了探究公路施工安全事故诱因及其影响关系,基于"4M"理论和事故致因"2-4"模型,识别公路工程施工安全事故致因因素并确定模型框架,运用SPSS Modeler软件对2007~2017年426起事故进行关联规则挖掘,采取路径分析与重要度分析,构建出公路工程施工安全事故致因模型。结果表明:施工单位内外部原因共同引发公路工程施工安全事故,外部原因来源于建设单位、监理单位和勘察设计单位的安全管理缺失,而施工单位内部影响因素中,人的不安全动作、物的不安全因素、不良的生产环境和自然环境是事故发生的直接原因,无效的安全监管和作业层安全素质及能力不强是间接原因,根本原因是施工程序和技术方案存在缺陷,根源原因是决策层和管理层的安全素质及能力有待提高。该模型系统展现了工程施工项目安全事故致因因素的影响关系和重要程度,为公路工程施工安全事故预防提供指导。     

乌鲁木齐市PM_(2.5)和PM_(2.5~10)中碳组分季节性变化特征

2011年1月至12月在乌鲁木齐市区用膜采样法采集了大气PM_(2.5)和PM_(2.5~10)样品,并利用热光/碳分析仪测定了其中有机碳(OC)和元素碳(EC)的质量浓度.通过OC与EC的粒径分布特征、比值和相关性的分析,初步分析了乌鲁木齐市大气可吸入颗粒物中碳质气溶胶污染特征,并用OC/EC比值法估算了二次有机碳(SOC)的浓度.结果表明,PM_(2.5)和PM_(2.5~10)的年平均质量浓度分别为92.8μg/m~3和64.7μg/m~3.PM_(2.5)中OC和EC的年平均浓度分别为13.85μg/m~3和2.38μg/m~3,PM_(2.5~10)中OC和EC的年平均浓度分别为2.63μg/m~3和0.57μg/m~3.OC和EC四季变化趋势基本一致,季浓度最高.碳组分主要集中于PM_(2.5)中,OC/EC比值范围为3.62~11.21.夏季和秋季的PM_(2.5)和PM_(2.5~10)中OC和EC的相关性较好(R20.65).估算得出的PM_(2.5)和PM_(2.5~10)中SOC的估算浓度为2.31~11.98μg/m~3和0.38~1.49μg/m~3.     

A novel bioremediation strategy for petroleum hydrocarbon pollutants using salt tolerant Corynebacterium variabile HRJ4 and biochar

The present work aimed to develop a novel strategy to bioremediate the petroleum hydrocarbon contaminants in the environment. Salt tolerant bacterium was isolated from Dagang oilfield, China and identified as Corynebacterium variabile HRJ4 based on 16S rRNA gene sequence analysis. The bacterium had a high salt tolerant capability and biochar was developed as carrier for the bacterium. The bacteria with biochar were most effective in degradation of n-alkanes (C16, C18, C19, C26, C28) and polycyclic aromatic hydrocarbons (NAP, PYR) mixture. The result demonstrated that immobilization of C. variabile HRJ4 with biochar showed higher degradation of total petroleum hydrocarbons (THPs) up to 78.9% after 7-day of incubation as compared to the free leaving bacteria. The approach of this study will be helpful in clean-up of petroleum-contamination in the environments through bioremediation process using eco-friendly and cost effective materials like biochar.     

以三乙烯四胺为前驱体合成的离子液体对CO2的吸收效果研究

以三乙烯四胺(TETA)为阳离子前驱体合成多胺基离子液体([TETAH]+[Cl]-、[TETAH]+[NO_3]~-、2[TETAH]+[SO_4]~(2-)和[TETAH]+[BF_4]~-),以CO_2摩尔吸收量和CO_2平均吸收速率为评价指标,优选出对CO_2吸收效果最优的2[TETAH]+[SO_4]~(2-)离子液体.进一步考察在不同含水率、气体流量和温度等因素下2[TETAH]+[SO_4]~(2-)离子液体对CO_2的吸收效果,结果表明:2[TETAH]+[SO_4]~(2-)吸收CO_2的最佳条件为含水率30%、气体流量50 m L·min~(-1)、温度10℃,此时CO_2饱和摩尔吸收量达到1.325 mol·mol~(-1),各因素对CO_2吸收量的影响大小顺序为含水率气体流量温度.     

镰刀菌(Fusarium sp.)对2,4,6-三氯苯酚的降解特性及其机制

为了解镰刀菌(Fusarium sp.)降解2,4,6-三氯苯酚(TCP)的因素影响规律,研究了温度、p H、外加碳源、氮源、氯离子及TCP浓度对其降解特性的影响,分析了其降解动力学与降解途径.结论:镰刀菌能以TCP为唯一碳源和能源物质进行生长繁殖,TCP降解最适条件为:氮源Na NO3(0.2 g·L~(-1)),30℃,p H=6~7.外加碳源葡萄糖对降解TCP具有明显的抑制作用.氯离子浓度低于0.2 g·L~(-1)时对降解TCP具有一定的促进作用,但随着氯离子浓度的增加,TCP的降解受到了抑制.镰刀菌对TCP降解速率随着其浓度的升高而减缓.镰刀菌能降解10~50 mg·L~(-1)的TCP,其降解反应符合零级降解动力学方程.镰刀菌降解TCP过程中检测到2,6-二氯苯酚(RT 12.521 min),可推测TCP是通过2,6-二氯苯酚途径进行降解的.     

台风“麦德姆”福州降水δ18O特征及水汽来源分析

大气降水的氢氧同位素不仅在长时间尺度和短时间尺度上对气候环境有一定的响应,而且在极端天气事件中也响应强烈。论文基于2014年7月23—24日10号台风麦德姆登陆前后福州降水的氢氧稳定同位素分析,发现台风麦德姆降水的δ¹⁸O变化范围为-7.2‰~-15.4‰,整个降雨过程分为3个阶段：阶段1（23日3：00至23日12：00）,雨水δ¹⁸O相对偏正（加权平均值为-7.8‰）,降水开始增加,主要受台风外围环流的影响;阶段2（23日12：00至24日8：00）,雨水δ¹⁸O显著偏负（加权平均值为-13.9‰）,采样点降水量达134.8 mm,约占观测时段降水量的78%,降雨量效应明显,主要受台风云雨区影响;阶段3（24日8：00至24日17：00）,雨水δ¹⁸O偏正（加权平均值为-9.2‰）,降水减少,台风远离福州。通过降水δ¹⁸O的阶段性特征以及过量氘,结合水汽输送通量与HYSPLIT-4模拟水汽轨迹分析,确定此次降水的水汽源主要来自西北太平洋水汽通道与孟加拉湾和南海水汽通道。     

阴、阳离子影响离子液体溶解甲烷性能的研究进展

煤矿抽采出的低浓度瓦斯直接排空不仅浪费清洁能源而且加剧温室效应。离子液体(IL)是近年来用于气体分离的热点研究对象。综述了利用IL分离气体,特别在溶解CH_4气体方面的研究进展,归纳了具有高效溶解CH4能力的IL结构特征,以及阴阳离子对IL溶解CH_4的影响规律。分析结果表明CH_4在大部分ILs中的溶解度较小;与咪唑类ILs相比,阴离子为[FAP]~-、[doc]~-、[Tf_2N]~-、[TMPP]~-,阳离子取代链为长烷烃的季膦类和季胺类ILs具有更强的溶解CH_4的能力。特别是[P4444][TMPP]和[P(14)666][TMPP]对CH_4表现出优越的溶解性,可考虑用这2种ILs存储CH_4。至于两者能否用于浓缩CH_4,还需实验测试[P4444][TMPP]和[P(14)666][TMPP]溶解CO_2和N_2的情况,以及对溶解过程的影响。     

Feasible conversion of solid waste bauxite tailings into highly crystalline 4A zeolite with valuable application

Bauxite tailings are a major type of solid wastes generated in the flotation process. The waste by-products caused significant environmental impact. To lessen this hazardous effect from poisonous mine tailings, a feasible and cost-effective solution was conceived and implemented. Our approach focused on reutilization of the bauxite tailings by converting it to 4A zeolite for reuse in diverse applications. Three steps were involved in the bauxite conversion: wet-chemistry, alkali fusion, and crystallization to remove impurities and to prepare porous 4A zeolite. It was found that the cubic 4A zeolite was single phase, in high purity, with high crystallinity and well-defined structure. Importantly, the 4A zeolite displayed maximum calcium ion exchange capacity averaged at 296 mg CaCO₃/g, comparable to commercially-available zeolite (310 mg CaCO₃/g) exchange capacity. Base on the optimal synthesis condition, the reaction yield of zeolite 4A from bauxite tailings achieved to about 38.43%, hence, this study will provide a new paradigm for remediation of bauxite tailings, further mitigating the environmental and health care concerns, particularly in the mainland of PR China.     

Prenatal screening and diagnosis of neural tube defects

This review article discusses prenatal screening and diagnosis of neural tube defects (NTD). High detection rates occur in countries operating ultrasound screening programmes because classical two-dimensional ultrasound cranial signs (lemon shaped head, banana cerebellum, ventriculomegaly) are important diagnostic clues to the presence of spina bifida. Careful evaluation of both the spine and a search for other abnormalities is warranted. Important prognostic information for spina bifida relates to the lesion level, with a “watershed” between L3 and L4 marking a very high chance of being wheelchair bound with the higher lesions. Three-dimensional ultrasound using multiplanar views can achieve diagnostic accuracy within one vertebral body in around 80% of patients. There are high rates of pregnancy termination for spina bifida in many European countries, but the use of new imagining techniques allow better prediction of outcome, and consequently a refinement of prenatal counselling. Copyright © 2009 John Wiley & Sons, Ltd.