Thermodynamic method for the prediction of solid CO2 formation from multicomponent mixtures

The increase in GHG concentration has a direct effect on global climate conditions. Among the possible technologies to mitigate GHG emissions, CCS is being accepted to gain emission reduction. Such technology also involves cryogenic CO₂ capture processes based on CO₂ freeze-out or where the formation of solid CO₂ must be avoided. Captured CO₂ is usually transported in pipelines for the reinjection.The risk associated to the release of CO₂ is due to the changing temperatures and pressures the system may experience, which can lead to the deposition of solid CO₂ where it must be avoided. Prolonged exposure to dry ice can cause severe skin damage and its resublimation could pose a danger of hypercapnia. It is, thus, necessary to build up a tool able to predict the conditions in which CO₂ can freeze-out.A thermodynamic methodology based on cubic EoSs has been developed which is able to predict solid–liquid–vapor equilibrium of CO₂ mixtures with n-alkanes or H₂S which are usually found in equipment for acidic gas, mainly natural gas, treatment.The focus is a detailed analysis of the method performances when more than two components are present since, for such a case, literature does not provide significant modeling results.     

基于密度泛函理论模拟单壁碳纳米管对五种核酸碱基的吸附

基于密度泛函理论,模拟了单壁碳纳米管(SWNTs)对5种碱基的吸附作用.考察了SWNTs直径、电荷转移量、碱基最高占据分子轨道能(EHOMO)和最低未占据分子轨道能(ELUMO)与SWNTs吸附碱基的吸附能之间的关系.结果表明,随着SWNTs直径的增大,SWNTs吸附碱基的吸附能降低.SWNT(6,6)吸附5种碱基的最低吸附能Emin与由碱基转移到SWNTs的电荷转移量(Q)及碱基的EHOMO线性负相关,相关系数分别为-0.966和-0.804(P<0.05).吸附后SWNTs与碱基的前线轨道无重叠,且SWNTs电子结构未受影响,表明吸附行为属于物理吸附.     

阳澄湖水源中典型嗅味物质测定与来源分析

以阳澄湖水源为研究对象,采用固相微萃取-气质联用法测定水中2-甲基异莰醇(2-MIB)、土臭素(GSM)、2,4,6-三氯苯甲醚(2,4,6-TAC)、2,3,4-三氯苯甲醚(2,3,4-TAC)、2,3,6-三氯苯甲醚(2,3,6-TAC)、2-异丙基-3甲氧基吡嗪(IPMP)、2-异丁基-3甲氧基吡嗪(IBMP)、β-环柠檬醛、β-紫罗兰酮、异氟尔酮等10种典型嗅味物质,并分析可能的来源藻类.以2018年1月-12月阳澄湖水源中优势藻种为基础,建立以上述嗅味物质为变量的多元线性回归模型.结果表明,水源中2-MIB、GSM、β-环柠檬醛、β-紫罗兰酮、异氟尔酮5种嗅味物质与直链藻、针杆藻、鱼腥藻、色球藻、颤藻、微囊藻、束丝藻7种藻类有较强的相关性.     

Quantitative assessment in safety reports of the consequences from the detonation of solid explosives

Safety reports are mandatory documents in member states of European Union whenever any threshold limits of amounts of either stored or processed hazardous substances are exceeded. After a short introduction to EU Seveso Directives on major-accident hazards involving dangerous substances and to the transposition and implementation by member states, with a brief comment on last 2012/18/EU Directive (also known as Seveso III directive), the paper focuses on drafting of safety reports for industrial activities involving solid explosives. Specifically, the quantitative assessment of consequences from detonation is tackled respect to the side-on overpressure and the debris production. Both direct and inverse problems are illustrated to determine respectively the overpressure value at a given distance, and the explosive amount that allows respecting the regulations. Their solution is based on either analytic or numerical techniques and being based on recent scientific publications on the matter either evaluates or zeroes nonlinear algebraic equations. The availability of these equations avoids grounding the consequences assessment on diagrams and nomograms that otherwise would lead to interpretation and usage errors besides avoiding the automatic solution of the inverse problem. The paper focuses also on details such as embankment, crater, munitions, rocket propellant, building structure, and wall material that, at different levels, play a role in the assessment of detonation consequences. A discussion on debris formation, the available literature, and the evaluation of the impact probability of fragments on both fixed and moving targets closes the paper.     

Municipal solid waste management in South Africa: from waste to energy recovery through waste-to-energy technologies in Johannesburg

ABSTRACT

“Waste-to-energy” (WTE) technologies have been presented as one of the avenues to improve the management of solid waste whilst promoting clean and healthy urban environments through the recovery of waste and generation of energy. Research suggests that with the right investment in technologies and institutional changes, waste can potentially become a resource that can contribute to the socio-economic development of cities. It is in this context that this paper presents a review of the literature on WTE technologies and their implications on sustainable waste management in urban areas. The paper particularly contributes to our understanding of WTE technologies and its potential on Municipal Solid Waste Management (MSWM) in Johannesburg, South Africa. It is estimated that the city of Johannesburg’s landfills airspace will be completely depleted by year 2023. This projection becomes a motivation for the identification of suitable WTE alternative avenues to manage waste in the city. The paper argues that WTE technologies can contribute significantly to sustainable waste management, economic growth, ecological and environmental well-being.     

The effect of barriers on reducing thermal heat fluxes from a hydrocarbon pool fire

The radiant heat flux from a pool fire is frequently calculated using the solid flame model, where the flame envelope is approximated as a stationary cylinder whose surface emits thermal radiation at a constant rate. Radiant heat flux calculations using the solid flame model assume the target to be at a given elevation, typically at ground level, and to have an unobstructed view of the fire. The presence of obstacles (e.g., walls, buildings, etc.) or terrain features that would create shaded areas and provide shielding of a target from the fire is typically neglected in these calculations: this is a conservative approach, but it is not accurate. This paper presents a methodology to utilize the solid flame model to calculate the heat flux to a target while taking into account the presence of an obstruction between the target and the fire. The shielded solid flame method can quantitatively account for the presence of obstacles as a passive mitigation measure and allows project developers or designers to optimize their facility layout to meet safety requirements. The methodology presented in this paper uses the same correlations found in currently used solid flame models (e.g., LNGFIRE3), therefore, it remains consistent with current regulatory requirements for LNG facilities in the U.S.     

养殖废水中9种大环内酯及林可酰胺类抗生素的同时测定及分析方法研究

采用固相萃取-超高效液相色谱三重四极杆质谱联用法,建立了同时测定养殖废水中9种大环内酯及林可酰胺类抗生素的方法,并对样品pH值、保存时间、洗脱溶剂、上样流速及过滤材质等进行了优化。测定结果表明,pH值为6,过滤材质为聚丙烯（GHP）,上样速度为5 mL/min时,9种抗生素的加标回收率最优,为71.4%～126%,相对标准偏差最小,为2.4%～7.1%,标准曲线的线性最好,相关系数为0.998 5～0.999 5,检出限为0.78～1.22 ng/L。该方法灵敏度高、检出限低、测定结果准确,能够广泛应用于养殖废水中大环内酯及林可酰胺类抗生素残留量的监测分析。     

A choice experiment analysis for solid waste disposal option: a case study in Malaysia

In Malaysia, most municipal wastes currently are disposed into poorly managed 'controlled tipping' systems with little or no pollution protection measures. This study was undertaken to assist the relevant governmental bodies and service providers to identify an improved waste disposal management strategy. The study applied the choice experiment technique to estimate the nonmarket values for a number of waste disposal technologies. Implicit prices for environmental attributes such as psychological fear, land use, air pollution, and river water quality were estimated. Compensating surplus estimates incorporating distance from the residences of the respondents to the proposed disposal facility were calculated for a number of generic and technology-specific choice sets. The resulting estimates were higher for technology-specific options, and the distance factor was a significant determinant in setting an equitable solid waste management fee.     

Valorization of solid waste in sugar factories with possible applications in India : A review

Sugar production is a major agro-based industry in India that generates various solid wastes viz. sugarcane trash, bagasse, press mud and bagasse fly ash. This work examines the state-of-the-art in innovative value added products that can be obtained from the transformation of these wastes. Challenges in implementing these waste valorization solutions are also highlighted. It is observed that the extent of research and adoption of these solutions vary considerably. Both industry involvement as well as government encouragement is required in translating the research findings into commercial products.     

Formulation of criteria for pollution control on cement products produced from solid wastes in China

The process of producing cement products from solid waste can increase the level of pollutants in the cement products. Therefore, it is very important to establish a pollution control standard for cement products to protect the environment and human health. This paper presents acceptance limits for the availability of heavy metals in cement products which have been produced from solid wastes and explains how the limits have been calculated. The approach and method used to formulate these criteria were based on EN 12920. The typical exposure scenarios used in this paper involve concrete being used for drinking water supply pipelines and concrete pavements and are based on an analysis of typical applications of cement in China, and the potential for contact with water. The parameters of a tank test which was based on NEN 7375 were set in accordance with the environmental conditions of typical scenarios in China. Mechanisms controlling the release of heavy metals in concrete and a model for that release were obtained using the leaching test. Finally, based on acceptance criteria for drinking water and groundwater quality in China, limit values for the availability of heavy metals in concrete were calculated.