An improved extraction method to determine the initial emittable concentration and the partition coefficient of VOCs in dry building materials

Based on the extraction method presented by Smith et al. (2008), this paper proposes an improved method, the multi-emission/flush regression method, to simultaneously determine the initial emittable concentration and the partition coefficient. Compared to the extraction method, the proposed method has the following advantages: (1) it is unnecessary for the target volatile organic compounds (VOCs) to emit completely from the material, thus greatly reducing experimental time; (2) it provides a simpler way to obtain the partition coefficients of VOCs for tested materials and can avoid the measurement uncertainties at low VOC concentrations which often occur during the last few cycles of the extraction method; (3) it does not require grinding the building material into powders thus making this method more convenient to use. Comparisons were made between the initial emittable VOC concentrations determined by the original extraction method and the proposed method. Results show good agreements between these two methods. To further validate the proposed method, the type of static chamber developed by Wang et al. (2006) was used to conduct the experiment for a type of medium density board, and formaldehyde was selected as the target compound. Based on the initial emittable concentration and partition coefficient obtained using the proposed method, and the diffusion coefficient obtained by the mercury intruding porosimetry, the chamber formaldehyde concentration was predicted and compared with the experimental measurements. Results show that the predicted chamber VOC concentration using the measured parameters agree well with the experimental data.     

Long-term variations of CO2 trapped in different mechanisms in deep saline formations: A case study of the Songliao Basin,China

The geological storage of CO₂ in deep saline formations is increasing seen as a viable strategy to reduce the release of greenhouse gases to the atmosphere. There are numerous sedimentary basins in China, in which a number of suitable CO₂ geologic reservoirs are potentially available. To identify the multi-phase processes, geochemical changes and mineral alteration, and CO₂ trapping mechanisms after CO₂ injection, reactive geochemical transport simulations using a simple 2D model were performed. Mineralogical composition and water chemistry from a deep saline formation of Songliao Basin were used. Results indicate that different storage forms of CO₂ vary with time. In the CO₂ injection period, a large amount of CO₂ remains as a free supercritical phase (gas trapping), and the amount dissolved in the formation water (solubility trapping) gradually increases. Later, gas trapping decrease, solubility trapping increases significantly due to the migration and diffusion of CO₂ plume and the convective mixing between CO₂-saturated water and unsaturated water, and the amount trapped by carbonate minerals increases gradually with time. The residual CO₂ gas keeps dissolving into groundwater and precipitating carbonate minerals. For the Songliao Basin sandstone, variations in the reaction rate and abundance of chlorite, and plagioclase composition affect significantly the estimates of mineral alteration and CO₂ storage in different trapping mechanisms. The effect of vertical permeability and residual gas saturation on the overall storage is smaller compared to the geochemical factors. However, they can affect the spatial distribution of the injected CO₂ in the formations. The CO₂ mineral trapping capacity could be in the order of 10 kg/m³ medium for the Songliao Basin sandstone, and may be higher depending on the composition of primary aluminosilicate minerals especially the content of Ca, Mg, and Fe.     

熔融盐在废弃物处理中的应用研究进展

针对传统的废弃物处理技术存在的问题,从介绍国内外熔融盐在废弃物处理中的研究进展,总结其主要的工艺类型和使用的熔融盐,比较传统的处理技术4个方面探讨了新型的熔融盐处理技术,在此基础上指出了目前熔融盐处理技术研究存在的问题和今后的研究方向.     

基于ArcSDE的地震紧急救援数据库建设

提出了建设地震紧急救援数据库的必要性,阐述了地震紧急救援数据库的建设目标,分析了ArcSDE的基础原理,以四川省紧急救援队为例,介绍了利用ArcSDE技术构建地震紧急数据库的建设方法。     

基于随机化Pushover的结构整体抗震可靠度参数分析

为了研究使用随机化Pushover方法进行RC框架结构整体抗震可靠度计算过程中相关参数的适应性,使用Matlab调用SAP2000编制出基于随机化Pushover的结构整体抗震可靠度程序,以一榀11层RC框架结构为例,通过该程序统计出不同参数下结构最大层间位移角的分布情况及整体失效概率,并以大样本实际地震波进行时程分析所统计出的相应结果为基准进行对比。结果表明,在常规参数设置下随机化Pushover方法统计出的最大层间位移角分布情况和结构整体失效概率与大样本时程分析结果有较大差异,然后提出了一种修正方式,有效地减小了两者的差异,并以某算例验证了该修正方式的适用性。     

改性沸石去除水中低浓度氨氮的研究

分别利用无机盐、无机酸和稀土对天然沸石进行了改性处理,并从理论上阐述了不同方法对沸石进行改性的机理,提出了改性沸石的最佳制备方法,并采用X衍射的分析手段观察化学处理对载体的影响,探讨了改性沸石对NH4 吸附动力学以及再生实验.研究表明,3种方法均不同程度地提高了沸石去除氨氮的能力,其中利用无机盐改性的沸石的效果最佳,对NH4 的吸附动态符合Freundlich方程,与传统的化学凝聚法和生物法相比,具有工艺简单、高效、经济等优点.无机盐改性沸石制备最佳条件是:溶液中钠离子浓度为0.8 mol/L,在水浴温度70～75 ℃时,按固液比1∶50投加沸石,浸渍时间为2 h,过滤后滤饼在100 ℃下干燥1 h.     

木材胶粘剂生产中的污染及防治

阐述了木材胶粘剂－脲醛树脂胶粘剂（ＵＦ）,密胺甲醛树脂胶粘剂（ＭＦ）,酚醛树脂胶粘剂（ＰＦ）生产过程中产生的废气,釜垢及碱洗废液的污染,提出了从工艺上改善排放条件及治理的方法,同时提出了控制产品中游离甲醛的方法。     

硅烷化对云南松木材表面疏水性和润湿性的影响

利用三甲基氯硅烷(TMCS)对云南松木材进行表面改性,研究了木材改性前后的吸水率和表面接触角等性质的变化。通过傅立叶变换红外光谱(FTIR),对改性后的云南松进行了表征。结果表明,改性0—10d的木材吸水率从138.4%下降到111.1%;木材分别经过1d、2d和4d的硅烷化改性,甘油表面接触角从未改性时的88.7°上升到99.0°,蒸馏水表面接触角从54.2°上升到69.1°,二碘甲烷则从40.0°下降到31.9°。木材表面吸水率和表面接触角的变化证明,改性后木材表面的疏水性增强。与未改性的木材相比,经硅烷化处理后木粉的FTIR在1265cm-1位置出现了Si-(CH3)3特征峰,表明木材表面疏水性增强是由表面羟基与TMCS间发生了硅烷化反应所致。     

长输管道工程施工期环境监理初探 ——以中缅油气管道工程（缅甸段）为例

中缅油气管道工程(缅甸段)首次在长输管道建设项目中引入独立第三方环境监理,目的是保证工程环境保护达到国际一流水平,促进管道建设与当地的经济社会、自然环境的和谐可持续发展。通过工程的环境监理实践,分析了长输管道施工准备阶段、施工期和试运行期的环境监理要点和工作重点,介绍了环境监理的工作方法,并对完善环境监理工作提出了建议,为长输管道工程环境监理进行了初步实践探索。