REVIEW OF VOLATILE ORGANIC COMPOUNDS DERIVED FROM POLYETHYLENE

The formation of volatile organic compounds (VOCs) in polyethylene (PE) is a topic of concern to industries involved in the packaging of items such as foodstuffs and pharmaceuticals that are sensitive to organoleptic contamination. This article reviews the available literature on VOCs that originate from PE during its manufacture, processing, storage, and service life. The package–product interactions that may occur between PE and packaged foodstuffs are also considered together with the wide range of methods for the analysis of VOCs. The following analytical methods are discussed: (i) sensory evaluation, (ii) chromatographic techniques and their associated sampling techniques, including the “hot-jar” method and dynamic headspace sampling, (iii) gas chromatography–olfactory sensing, and (iv) artificial olfaction or “electronic nose” technology.     

饮用水中有机物的状况及其检测方法

本文介绍了当前我国饮用水水源及饮用水中有机物的状况，并对饮用水中有机物的富集和检测分析方法进行了比较全面的综述。     

NUMERICAL SIMULATION OF VOLATILE ORGANIC COMPOUNDS EVAPORATION IN CLOSED SPACES

Abstract

This paper deals with the simulation of VOCs concentration dispersion, evaporated from flooring materials, with the purpose of understanding VOCs evaporation and dispersion mechanisms. A test chamber is examined whose flooring material emits a number of VOCs. Given the area specific ventilation rate and considering it as boundary conditions, experimental data for the examined compounds concentration, the dispersion of the VOCs concentrations is examined under steady state and transient conditions. The model developed is used in conjunction with a general - purpose CFD code, PHOENFCS, that can provide detailed information on the flow as well as concentration fields. The results of the above two simulation cases are used as a guide for two other cases, where faster restoration of the air indoor quality was investigated by changing the ventilation rate in the chamber. The simulation results were used as a basis for further analysis for VOC evaporation for other flooring materials; this will allow proper material selection as well as proper ventilation system for a more healthy and comfortable environment in a building.     

NUMERICAL SIMULATION OF VOLATILE ORGANIC COMPOUNDS EVAPORATION IN CLOSED SPACES

This paper deals with the simulation of VOCs concentration dispersion, evaporated from flooring materials, with the purpose of understanding VOCs evaporation and dispersion mechanisms. A test chamber is examined whose flooring material emits a number of VOCs. Given the area specific ventilation rate and considering it as boundary conditions, experimental data for the examined compounds concentration, the dispersion of the VOCs concentrations is examined under steady state and transient conditions. The model developed is used in conjunction with a general - purpose CFD code, PHOENFCS, that can provide detailed information on the flow as well as concentration fields. The results of the above two simulation cases are used as a guide for two other cases, where faster restoration of the air indoor quality was investigated by changing the ventilation rate in the chamber. The simulation results were used as a basis for further analysis for VOC evaporation for other flooring materials; this will allow proper material selection as well as proper ventilation system for a more healthy and comfortable environment in a building.     

超临界水氧化法去除废水有机氮的工艺和动力学研究

<正> 引言 超临界水氧化法(SCWO)是一种新型高效的废水和废物处理技术.水在超临界条件下具有独特的物理化学性质,它能与非极性物质如烃类和其他有机物完全互溶,而无机物特别是盐类在超临界水中的溶解度很低.另外,超临界水可以与气体(如空气、氧气、二氧化碳等)完全互溶.这些性质使得超临界水作为反应介质的超临界水氧化法具有独特的优势.在超临     

有机物存在下水体中三价铬的去除

通过对多种有机物如草酸、柠檬酸,柠檬酸钠,酒石酸钾钠,草酸铵、柠檬酸三铵、酒石酸,EDTA分别存在下,对水体铬(Ⅲ)去除影响对比,选择酒石酸、草酸、柠檬酸和柠檬酸钠作为共存有机物,氢氧化钙或氢氧化钠做沉淀剂,三氯化铝或三氯化铁为共沉淀剂,研究水体铬(Ⅲ)去除情况,并对铬去除及影响机理进行了探讨.结果表明,所选有机物的存在,不同程度地影响水体中三价铬的去除,三氯化铝和三氯化铁的存在,有助于水体中三价铬在有机物存在情况下的去除,且多数情况下,三氯化铝的共沉淀效果好于三氯化铁.Ca(OH)2、NaOH的最佳用量为理论用量的150%,且Ca(OH)2的沉淀效果好于NaOH.     

饮水中有机污染物的危害及对策

饮水有机污染是现代社会面临的严峻挑战，日益污染的水质对人类健康造成极大威胁。提高饮水的有机污染物控制指标及水处理管理水平，并在常规给水处理工艺的基础上进行有效的深度处理，有着重要的现实意义。     

WATER - CORN EQUILIBRIUM: TEMPERATURE DEPENDENCY OF THE G.A.B. MODEL PARAMETERS AND CALCULATION OF THE HEAT OF SORPTION

ABSTRACT

By using sorption data for com in the range of 4.4-60°C, the temperature (T) variations of the GAB. model parameters (M_m, C_B and k) were studied. As only the monolayer moisture (M_m) varied (decreased) with temperature, a generalized GAB equation of four total parameters was obtained. This, together with the Clapeyron equation allowed a method to calculate the heat of sorption (L_b) as a function of T and moisture content (M). For each temperature, Lb presented a maxinuin some 30% above the heat of vaporization of water (L_f), which occurred around the M_m, in congruence with the sorption theory. A similar behavior of L_b was found using the Othmer method. In contrast, the Gallaher equation predicted an ever increasing L_b up to 3 L_f at very low moistures. The GAB-Clapeyron method is then proposed to calculate L_b as a function of M and T.     

微量有机化合物和一氧化碳催化燃烧反应器数学模拟

建立了废气中含有甲苯、一氧化碳、丙烯混合物催化燃烧反应器的数学模型.多组分混合物催化燃烧反应动力学模型采用吸附解离态的氧与吸附态的反应物反应的机理推导得到了反应速率方程.模拟计算了废气处理量、废气中各组分的浓度、床层入口温度对转化率的影响.     

EFFECT OF TEMPERATURE ON WATER SORPTION EQUILIBRIUM OF ONION (ALLIUM CEPA L)

ABSTRACT

Results of the experimental measurement of sorption isotherms at different temperatures obtained by the standard gravimetric method showed the typical sigmoid shape of products rich in carbohydrates. The temperature had the expected effect predicted by the theory of physical adsorption i,e the quantity of sorbed water at a given water activity increased as the temperature decreased. The amount of adsorbed or desorbed water per unit weight of solid depends on the equilibrium temperature. The increase of the temperature results in increase of water activity for the same moisture content which in increases the rates of reactions leading to quality deterioration. As the water activity is raised beyond the intermediate region, water is sorbed by low molecular weight constituents resulting in shifting the isotherm upward. The values of the net isosteric heat of desorption were found to be higher than those or adsorption, which indicates that the binding energy for the latter is higher. At low moisture content the heats of desorption is much higher than that of adsorption.     

水中痕量挥发性酚类的流动注射——分光光度测定

建立了测定水中痕量挥发性酚类的４ － 氨基安替比林（４ － ＡＡＰ） － 流动注射分光光度法。将含挥发性酚类的预蒸馏水样注入到载流中,与４ － ＡＡＰ试剂流混合,在Ｋ２Ｓ２Ｏ８ 流（ｐＨ１１．０） 的催化下,反应形成红色吲哚酚安替比林染料,在λｍａｘ 为５１０ ｎｍ 处对其进行分光光度检测。线性范围为０．０ ～１６．０ ｍｇ／Ｌ 挥发性酚类,检测限为０．０３４ ｍｇ／Ｌ,测定频率为４０ 次／ｈ 。本法的灵敏度较高,选择性较好,分析速度快。测定工业废水中痕量挥发性酚类,获得满意结果。     

天然沸石用于去除水体中有机污染物的效果

用固定床吸附柱方法研究天然沸石,天然沸石和活性炭配合使用去除水中致色有机物的效果,并考察了它们对苯酚与苯胺的吸附作用,结果表明,天然沸石对自来水中致色有机物有明显去除效果,与活性炭配合使用时,能将自来水中致色有机物基本去除,与活性炭不同,天然沸石地苯酚的吸附能力３成于苯胺。     

邛西北断块须二气藏水体特征及水侵动态分析

邛西构造须二气藏北断块是邛西须二气藏主产区,气藏地质储量大,区内4口井日产气量较大,生产受地层水影响较大,通过静态地质资料和4口生产井的生产动态特征分析表明：气藏裂缝水窜不可避免,水窜严重影响气井产能,通过产水动态及水体分布,综合考虑地质情况,可以分析出各井的水侵途径和水侵方向,为气藏的合理生产调整提供依据。     

WATER SORPTION ISOTHERMS OF FREEZE DRIED FISH SARDINES

Water sorption isotherms of freeze dried fish sardines were determined at 25, 40 and 50°C using an isopiestic method. Water sorption modeling was carried out using the five parameter Guggenheim-Anderson-deBoer (GAB) equation. The GAB equation was able to predict equilibrium moisture content (EMC) with a mean relative error of 7.4%. The correlation coefficient (R²) of the relationship between the actual and predicted values of EMC was 0.986. Modeling with GAB equation predicted monolayer moisture content (X_m) of 4.94% (d.b.). Net isosteric heat of sorption, determined using Clausius-Clapeyron equation, varied from 12.07 to 0.86 kJ/mol asmois ture content changed from 2.76 to 37.5% dry basis (d.b). Chemical composition analysis showed that fish sardine contained 71% (d.b.) crude protein, 10% (d.b.) fat and 15% (d.b.) ash.     

WATER SORPTION ISOTHERMS OF FREEZE DRIED FISH SARDINES

Water sorption isotherms of freeze dried fish sardines were determined at 25, 40 and 50°C using an isopiestic method. Water sorption modeling was carried out using the five parameter Guggenheim-Anderson-deBoer (GAB) equation. The GAB equation was able to predict equilibrium moisture content (EMC) with a mean relative error of 7.4%. The correlation coefficient (R²) of the relationship between the actual and predicted values of EMC was 0.986. Modeling with GAB equation predicted monolayer moisture content (X_m) of 4.94% (d.b.). Net isosteric heat of sorption, determined using Clausius-Clapeyron equation, varied from 12.07 to 0.86 kJ/mol asmois ture content changed from 2.76 to 37.5% dry basis (d.b). Chemical composition analysis showed that fish sardine contained 71% (d.b.) crude protein, 10% (d.b.) fat and 15% (d.b.) ash.     

水煤浆热解挥发分析出机理的研究

采用由日本岛津（SHIMADZU）公司生产的DTG-60H型热重-差热分析仪,对水煤浆在不同升温速率下的特性进行研究,升温速率分别为20C／min,30℃／min和50C／min．通过对水煤浆的热重分析数据的处理与分析,采用微分法和积分法相结合的方法,得到表征水煤浆热解反应挥发分析出的机理为Anti—Jander的三维扩散模型．实验表明,随着升温速率的增大,水煤浆热解反应的活化能也增大,与机理方程是吻合的．     

某自来水公司各工段水中有机物分析

本文就某自来水各工段的了水进行了研究,经过一系列处理,计算了有机残渣含量。通过ＧＣ－ＭＳ技术,鉴定了各工段水样中的有机物组分。     

UNIFICATION OF FRUIT WATER SORPTION ISOTHERMS USING ARTIFICIAL NEURAL NETWORKS

The chemical composition, water activity, temperature and equilibrium moisture content (EMC) for 10 selected fruits were determined. Two methods of water sorption modeling, the GAB equation and the artificial neural network (ANN) method, were compared for their ability to predict water sorption behavior. Unlike the GAB equation, which uses only physical data for modeling, the ANN method uses both physical and chemical compositional data to make predictions. The ANN was superior, in most cases, to that of the GAB equation, in predicting EMC. This superiority was due to the availability of the additional chemical compositional information. The ANN method could predict EMC with a mean relative error of 9.85% and a standard error (S _x ) of 1.59% EMC. The correlation coefficient (r ²) of the relationship between the actual and predicted values of equilibrium moisture content obtained by the ANN was 0.9938. The ANN model was able to show a temperature dependent crossing of water sorption isotherms, due to the dissolution of sugar crystals in the fruit. The ANN was also able to predict the extent of crossing, depending upon differences in the individual fruit chemical composition.     

UNIFICATION OF FRUIT WATER SORPTION ISOTHERMS USING ARTIFICIAL NEURAL NETWORKS

The chemical composition, water activity, temperature and equilibrium moisture content (EMC) for 10 selected fruits were determined. Two methods of water sorption modeling, the GAB equation and the artificial neural network (ANN) method, were compared for their ability to predict water sorption behavior. Unlike the GAB equation, which uses only physical data for modeling, the ANN method uses both physical and chemical compositional data to make predictions. The ANN was superior, in most cases, to that of the GAB equation, in predicting EMC. This superiority was due to the availability of the additional chemical compositional information. The ANN method could predict EMC with a mean relative error of 9.85% and a standard error (S_x) of 1.59% EMC. The correlation coefficient (r²) of the relationship between the actual and predicted values of equilibrium moisture content obtained by the ANN was 0.9938. The ANN model was able to show a temperature dependent crossing of water sorption isotherms, due to the dissolution of sugar crystals in the fruit. The ANN was also able to predict the extent of crossing, depending upon differences in the individual fruit chemical composition.     

小波在分析流态化系统多尺度动态行为中的应用

利用小波分解方法,对用激光相位多普勒颗粒分析仪（ＰＤＰＡ）、光纤探针及压差传感器同时测得的二维循环流化床中的信号进行了分解,并对分解信号和三种原始信号进行了比较．研究表明：将动态过程分解为三种尺度是合理的,ＰＤＰＡ信号包含了循环流化床所有尺度的全部信息．分解后三种尺度信号均具有混沌性态,但可预测性比原始信号好,为增加对动态过程的认知和建立较好的动态表达模型提供了途径．