Dispersion modeling of LNG-Vapor on land – A CFD-Model evaluation study

Based on methane from renewable resources, LNG is an alternative fuel for heavy and long-distance traffic in land transport. Contrary to its positive properties, the fuel contains risks from an explosion and extremely low temperatures for personal and infrastructure safety. CFD-models are suitable for doing risk analyses for arbitrary scenarios. For examining how to model for risk research the dispersion of LNG-vapor, this paper contains a model variant study, with an evaluation by experiments.This paper describes the use of the CFD-code ANSYS Fluent for simulating experiments of the ‘LNG Safety Program Phase II‘. The content of the well-documented experiments was the research of the vaporization rate of LNG on land and the dispersion of LNG-vapor in the air. Based on the comparison to two experiments, overall 12 CFD-model variants with varying thermal and turbulence parameters were examined how they affect the transient LNG-vapor dispersion in air.The definition of turbulence-boundary-condition at the domain borders had the biggest impact on modeling, followed by the turbulence model. The most accurate model variant had been applied for observing the spreading behavior of LNG-vapor in the air after evaporation on land and analyzing the influence of the LNG-composition to the dispersion. The results show that the mixture of LNG-vapor and the air in the free field is cooler than the ambient air and spreads like a heavy gas on the ground.     

纳米金修饰分子印迹聚合膜电极检测双酚A

以纳米金修饰玻碳电极为基础电极,以双酚A为模板分子,以邻氨基苯硫酚为聚合单体,采用循环伏安法电聚合制备分子印迹聚合膜,利用循环伏安和交流阻抗法研究电极的电化学特性。结果表明,双酚A在修饰电极表面的反应是一个受吸附控制的等电子、质子转移的不可逆反应。采用差分脉冲伏安法检测双酚A,线性范围为5. 0×10~(-6)mol/L～4. 0×10~(-4)mol/L,检出限为2. 3×10~(-7)mol/L。将该电极用于自来水和牛奶样品的测定,结果均为未检出,加标回收率分别为93. 5%和95. 4%,3次测定结果的RSD分别为4. 0%和5. 7%。     

Biochemical and histopathological changes of Biomphalaria alexandrina snails exposed to bisphenol A

The effects of sub-lethal concentrations of bisphenol A on some biochemical parameters in Biomphalaria alexandrina snail's hemolymph and tissues as well as on histological changes of the hermaphrodite gland were evaluated. Adult snails were exposed to sub-lethal concentrations for four weeks and samples of snails were investigated after two and four weeks. Total protein and albumin levels in hemolymph, as well as lipid peroxidation and glutathione contents of snails’ tissues, were measured. After two weeks of exposure, total protein content and albumin levels decreased in all groups. Elevation of lipid peroxidation levels was correlated with decreasing glutathione content in the treated snails. Histological examination of the hermaphrodite gland revealed deformations in eggs and affected sperm production.     

寻求湿度系数与风速关系的数学表达式

在中央气象局编制的《湿度查算表》和GB6999-86《环境试验用相对湿度查算表》的基础上,用最小二乘法与搜索法寻求湿度系数A与风速V关系的数学表达式,提出了湿度系数A适用风速V的参照表,这对提高相对湿度的测量准确度有一定帮助。     

（School of Life Science, Sun Yat-sen University, Guangzhou 510275, China）

Introduction B isphenol A (BPA ), 2,2-bis(4-hydroxyphenyl) propane (CA S 80-05-07), is a representative m aterial am ong endocrine disrupting chem icals (ED Cs) and has been extensively used as a raw m aterial of epoxy and polycarbonate resins, and also a…     

Photodegradation of bisphenol A in Fe(Ⅲ)-oxalate complexes solution

The aqueous photodegradation of bisphenol A (BPA) in the presence of Fe(Ⅲ)-oxalate complexes (Fe(Ⅲ)-Ox), which are common compositions of natural water, was investigated in this study. BPA underwent rapid indirect photolysis in Fe(Ⅲ)-Ox solution under simulated solar irradiation, proceeding pseudo-first-order kinetics. The photolysis rate increased with decreasing pH or initial processes of Fe(Ⅲ)-Ox complexes and contributed to the photooxidation of BPA, were determined by molecular probe and electron spin resonance (ESR) methods with the steady-state concentration of 2.56 × 10-14 mol/L. Superoxide anion radical (O2.-) was consistructural analysis of the intermediate photoproducts of BPA in Fe(Ⅲ)-Ox complexes solution, the possible degradation pathways of of Fe(Ⅲ) may affect the environmental fate of BPA in natural water significantly.     

A/O法在焦化废水处理中的应用

常州中天焦化有限公司污水处理站采用AO法处理焦化废水,该装置于1995年投入运行,至今运行状况良好。在此介绍了焦化废水的来源、水量、水质、工艺流程、经验和存在的问题,对运行中的几个阶段进行了分析和探讨。     

应用水解+A/O工艺治理化工废水的工程实践

兰州石化公司应用水解(酸化)+AO工艺组合治理化工废水。化工废水经水解(酸化)处理后,BOD5CODCr比值从<0.2提高到0.37,提高了化工废水的可生化性。该工艺利用兼氧和好氧微生物对高浓度化工废水处理后,CODCr的去除率达85%以上,NH3N的去除率达95%以上。     

斜网-混凝沉淀-A/O工艺处理白卡纸废水

采用斜网+混凝沉淀+A/O工艺处理白卡纸废水,平均CODCr去除率为97·9%,平均SS去除率为99·1%,出水各项指标达到《造纸工业水污染物排放标准》(GB3544-92)一级标准。以斜网装置回收废浆,过水量5~12m3/(m2·h),CODCr去除率52·8%,SS去除率53·7%。回收纤维获益相当于每吨纸节省成本33元,占总成本的2·5%。将剩余污泥回流到沉淀反应池,可降低投药量,节约总运行费用25%,并能减轻二次污染。     

双酚A降解菌的分离鉴定及降解基因的定位

从土壤中分离到一株双酚A降解菌W2。该菌可在饱和的双酚A溶液里以其为唯一碳源与能源生长。具有较强的双酚A降解能力。通过16SrDNA序列分析与形态与生理生化分析,该菌株为假单胞菌。通过质粒丢失实验、质粒转化实验证明该基因位于一个19kb左右的质粒上。