多孔介质中化学–热–水力–力学耦合过程本构模型和数值模拟

本文发展了一个多孔介质中的化学–热–水力–力学(CTHM)耦合本构模型。该模型基于文献[1]中多孔介质热–水力–力学(THM)本构模型、文献[2,3]中的污染物传输本构模型和文献[4]提出的化学–力学本构模型。在本构模型中引入化学软化函数以模拟孔隙水中有机污染物对多孔介质力学性质的影响。考虑了温度对污染物传输机制的影响。本文CTHM耦合本构模型已在多孔介质的热–水力–力学–污染物传输数学模型中建立。在CTHM本构模拟框架中对计及化学塑性效应、描述在热–水力–污染物传输耦合作用下多孔介质力学行为、在应力–吸力–温度四维空间中包含了五重屈服面的耦合本构模型发展了一致性切线模量矩阵。数值结果突出显示了污染物浓度在多孔介质化学–热–水力–力学(CTHM)耦合系统中的影响。     

排污河道的疏浚底泥在园林中的应用研究

通过温室盆栽试验，考察了将天津市大沽排污河疏浚底泥应用于园林绿地后，其对景观园林植物——黑麦草、紫花苜蓿生理特性的影响以及植物对重金属的积累和对有机物的降解情况，并对重金属在土壤中的迁移特性及其对地下水的潜在危害进行了评价。结果表明，施用30、60、90、120kg／m^2的底泥，黑麦草和紫花苜蓿的发芽率均随底泥施用量的增加而减小，但植物的株高、生物量和叶绿素含量均高于对照组的，表明底泥的施用不仅没有对植物的生理造成伤害，而且促进了植物的生长；两种植物积累的Pb^2＋、Zn^2＋、Cu^2＋、Ni^2＋量随着底泥施用量的增加而明显增加，但二者之间没有显著差异；土壤中有机污染物含量明显降低，且复杂的有机物被转化为易于被植物吸收利用的小分子有机物；土壤溶液中Zn^2＋浓度较高，需考虑其对环境的潜在危害。     

Distribution and transport of sediment-bound metal contaminants in the rio grande de tarcoles, costa rica (Central America)

A reconnaissance survey of the extent of metal contamination in the Rio Grande de Tarcoles river system of Costa Rica indicated high levels of chromium (Cr) in the fine-grain bed sediments (<60 μm) of tributaries downstream from leather tanneries (50–83 times Cr background or 3000–5000 μg/g). In the main channel of the river downstream of the San Jose urban area, Cr contamination in sediments was 4–6 times background and remained relatively constant over 50 km to the mouth of the river. Sediments from a mangrove swamp at the river mouth had Cr levels 2–3 times above background. Similar patterns of dilution were observed for lead (Pb) and zinc (Zn) sediment contamination, although the contamination levels were lower. The high affinity of Cr towards particulate phases, probably as Cr(III), allows the use of Cr contamination levels for delineating regions of deposition of fine-grained sediments and dilution of particle associated contaminants during transport and deposition.     

双区域内离散污染源的模拟及分析

为研究污染源对非污染源区域的影响,具体考虑室内污染源、室外污染物浓度以及室内与室外通风方式的作用,对双区域内一般离散气态污染物在室内的浓度水平进行模拟和分析。通过对污染源的研究表明:室内污染源浓度的成倍增加会导致两个区域平均浓度均成倍增加,并且区域平均浓度是区域本身浓度与室外浓度的叠加值。通过对通风方式的研究表明:在污染源区域设置排气扇是有效的排污方法,有利于改善室内人居环境。     

有机膨润土作为防渗垫层材料的性能研究

以十六烷基三甲基氯化铵为改性剂合成制备了有机膨润土,并考察其作为防渗垫层材料的性能.研究发现,有机膨润土能有效截留渗漏液中的有机污染物,阻止其向环境的迁移,具有较好的防渗效果.研究还发现,改性剂用量对防渗性能具有一定的影响,十六烷基三甲基氯化铵用量为5%(质量分数)时可以获得防渗性能较好的有机膨润土材料.当渗漏液体积足够大时,有机膨润土防渗层会被穿透,且穿透体积随渗漏液初始浓度的增加而减少.     

压风供氧状态下避难硐室污染物分布特性及热舒适性研究

为确定井下避难硐室合理供风量,采用RNGκ-ε模型和SIMPLE算法,对某100人避难硐室压风供氧状态下,不同供风量、散流器布置方案、空载和载人时生存区的污染物净化时间、通风效率、污染物(CO,CO2)浓度场分布和人体热舒适性等进行了数值模拟分析,并与现场实测结果进行了对比。模拟结果表明,若硐室内CO体积分数偏高,供风量应不低于0.1 m3/(min·人),并配合使用净化药剂尽快去除;常规避难状态下,供风量减小至600 m3/h,配合局部通风措施,即可满足人员避险和热舒适性基本要求。     

Comparison Between Dielectric Barrier Discharge Plasma and Ozone Regenerations of Activated Carbon Exhausted with Pentachlorophenol

In this study, two regeneration methods （dielectric barrier discharge （DBD） plasma and ozone （03） regeneration） of saturated granular activated carbon （GAC） with pentachlorophe- nol （PCP） were compared. The results show that the two regeneration methods can eliminate contaminants from GAC and recover its adsorption properties to some extent. Comparing the DBD plasma with 03 regeneration, the adsorption rate and the capacity of the GAC samples after DBD plasma regeneration are greater than those after 03 regeneration. 03 regeneration decreases the specific surface area of GAC and increases the acidic surface oxygen groups on the surface of GAC, which causes a decrease in PCP on GAC uptake. With increasing regeneration cy- cles, the regeneration efficiencies of the two methods decrease, but the decrease in the regeneration efficiencies of GAC after 03 regeneration is very obvious compared with that after DBD plasma regeneration. Furthermore, the equilibrium data were fitted by the Freundlich and Langmuir models using the non-linear regression technique, and all the adsorption equilibrium isotherms fit the Langmuir model fairly well, which demonstrates that the DBD plasma and ozone regeneration processes do not appear to modify the adsorption process, but to shift the equilibrium towards lower adsorption concentrations. Analyses of the weight loss of GAC show that 03 regeneration has a lower weight loss than DBD plasma regeneration.     

Effect of light on the concentration of ethyl carbamate in cachaça stored in glass bottles

This study sought to evaluate the influence of natural light on the concentration of ethyl carbamate (EC) in cachaças aged in wooden barrels and stored in glass bottles for a period of 6 months. The quantification of EC was achieved by HPLC using a fluorescence detector after previous derivation of the samples and standards with 9‐xanthydrol. All of the samples presented an EC concentration below the limit established by Brazilian legislation. The highest concentration found was 79.70 µg L^?1. As for the influence of light and storage period, 70% of the samples exhibited an influence of these parameters. Copyright © 2015 The Institute of Brewing & Distilling     

Experimental Investigation on Electrical Tracking of Epoxy Resin Compound with Silicon Rubber

The use of polymer materials as electrical insulators on transmission and distribution lines has been increas- ing such,as epoxy resin. Several advantages of using epoxy resin as an insulating material...     

Evaluation of ITS PCR and RFLP for Differentiation and Identification of Brewing Yeast and Brewery ‘Wild’ Yeast Contaminants

A reference library of ITS PCR/RFLP profiles was collated and augmented to evaluate its potential for routine identification of domestic brewing yeast and known ‘wild’ yeast contaminants associated with wort, beer and brewing processes. This library contains information on band sizes generated by restriction digestion of the ribosomal RNA‐encoding DNA (rDNA) internal transcribed spacer (ITS) region consisting of the 5.8 rRNA gene and two flanking regions (ITS1 and ITS2) with the endonucleases CfoI, HaeIII, HinfI and includes strains from 39 non‐Saccharomyces yeast species as well as for brewing and non‐brewing strains of Saccharomyces. The efficacy of the technique was assessed by isolation of 59 wild yeasts from industrial fermentation vessels and conditioning tanks and by matching their ITS amplicon sizes and RFLP profiles with those of the constructed library. Five separate, non‐introduced yeast taxa were putatively identified. These included Pichia species, which were associated with conditioning tanks and Saccharomyces species isolated from fermentation vessels. Strains of the lager yeast S. pastorianus could be reliably identified as belonging to either the Saaz or Frohberg hybrid group by restriction digestion of the ITS amplicon with the enzyme HaeIII. Frohberg group strains could be further sub‐grouped depending on restriction profiles generated with HinfI.