Production, consumption, and general equilibrium with physical constraints

This paper analyzes the consequences of integrating the conservation laws of mass and energy into the microeconomic models of production, consumption, and general equilibrium. We show that abstract models and especially general equilibrium theory are consistent with these physical constraints, but most applied and environmental economic models are not. We analyze the consequences of physical conservation laws for substitution possibilities and show that these constraints limit the number of independent substitution processes but not the value of the substitution elasticities. Finally, we propose a method for integrating physical constraints into static microeconomic models with a minimum of changes.     

煤渣吸附脱除含硫气体的实验研究

煤渣是煤炭燃烧后的残余物 ,由于其含有多种活性组分 ,且结构松散 ,比表面积大 ,是一种具有发展潜力的廉价吸附剂。本文利用重量法测量了在不同温度及压力情况下 ,煤渣对纯 SO2 气体和加入空气后对含硫气体的吸附能力 ;并利用 Freundlich经验式对实验数据进行了回归分析 ,得到了不同温度及压力情况下煤渣对含硫气体吸附能力的预测公式。本文同时还测量了煤渣的动态吸附性能 ,并利用实验数据求出了吸附总传质系数 ,为煤渣吸附脱硫的工业应用提供了实验数据和理论依据。     

火焰原子吸收分光光度法检测矿区环境的常见重金属

在红河州某矿区周围的土壤、池塘、鱼塘采集若干土壤、水样品.用氢氟酸-高氯酸-浓硝酸消化土壤样品,用硝酸处理水样品.实验中,原子吸收分光光度法的平均相关系数≧0.99906;测定元素的相对标准差从0.27%～1.67%,其平均相对标准偏差为1.005%;样品的回收率在102,8%～111.5%之间,表明该法可用于环境中的土壤样品和水样品中重金属元素的准确测定.在仪器的最佳工作状态,使用FAAS法检测矿区环境中的铅(Pb)、铜(Cu)、铬(Cr)、汞(Hg)的含量;依此来发现矿区周围环境的重金属分布规律和周围环境的安全性.     

Quantification of groundwater contamination in an urban area using integral pumping tests

In this paper, the integral groundwater investigation method is used for the quantification of PCE and TCE mass flow rates at an industrialized urban area in Linz, Austria. In this approach, pumping wells positioned along control planes perpendicular to the groundwater flow direction are operated for a time period on the order of days and sampled for contaminants. The concentration time series of the contaminants measured during operation of the pumping wells are then used to determine contaminant mass flow rates, mean concentrations and the plume shapes and positions at the control planes. The three control planes used in Linz were positioned downstream of a number of potential source zones, which are distributed over the field site. By use of the integral investigation method, it was possible to identify active contaminant sources, quantify the individual source strength in terms of mass flow rates at the control planes and estimate the contaminant plume position relative to the control planes. The source zones emitting the highest PCE and TCE mass flow rates could be determined, representing the areas where additional investigation and remediation activities will be needed. Additionally, large parts of the area investigated could be excluded from further investigation and remediation activities.     

Transient analysis of volatile organic compound concentrations for estimating emission rates

While emission rates of volatile organic compounds (VOCs) have been obtained for building materials, furnishings and processes in chambers, field measurements are more difficult. Procedures to estimate emission rates using transient analysis of VOC concentrations are described and applied in a two-story classroom/office building. The analysis employs semi-real-time VOC concentrations determined with a portable GC/FID and simultaneous air change rate measurements using tracer gas decay. The results of the analysis yield consistent values of emission rates for building materials ranging from 0.20 to 0.40 mg m⁻² h⁻¹ when normalized by floor area. Occupancy-related emissions were more difficult to estimate and covered a wider range from roughly 0.1 to 1.5 mg m⁻² h⁻¹. The test data were also analyzed in an attempt to determine sink parameters, but these efforts were not particularly successful. Furthermore, in these tests, the inclusion of sink effects did not significantly impact the estimated emission rates. While this paper offers a transient analysis approach that may lead to improved field estimates of VOC emission rates, it is not presented as a definitive methodology. Nevertheless, transient analysis has potential for use in other buildings, but simultaneous air change rate measurements are critical in its application in estimating VOC emission rates in the field.     

广州市夏、冬季室内外PM2.5质量浓度的特征

2004年7月2日至8月13日和2004年11月29日至2005年1月6日分别在广州市3种类型区域(一般城市区域、道路旁、工业源附近)9个居民住宅的室内和室外同步采集了PM2.5颗粒.采用标准称重法测定PM2.5质量浓度,得到广州市夏季住宅室内外PM2.5平均质量浓度分别为67.7、74.5 μg/m3,冬季室内外PM2.5平均质量浓度分别为109.9、123.7 μg/m3.广州市PM2.5平均质量浓度,与美国PM2.5标准相比,与国内PM10标准基础上假设的PM2.5限值相比,与其他一些国内、亚洲和欧美城市的文献记录相比,结果均显示广州市PM2.5处于相当严重污染状态.广州市PM2.5质量浓度呈现明显的空间分布特征和季节变化特征;PM2.5室内质量浓度并不总是低于室外质量浓度,反映了室内空气污染的存在.     

TF5池火平均质量损失速率简化模型及其高原环境下的适用性研究

通过池火在常压环境下燃烧时的质量损失机理分析,对火灾探测中欧洲标准试验火TF5(正庚烷池火)归纳推导出以辐射热反馈为主导的质量损失速率简化模型,并推广到拉萨高原低压环境.该模型建立了TF5池火平均质量损失速率与火焰温度四次方的正比关系,通过对火焰温度的测量,确定燃料液面所受的辐射热反馈功率,从而推算出燃料的平均质量损失速率.同时结合合肥及拉萨两地的TF5标准火实验,对模型进行了验证,实验结果表简化模型能够反映出不同气压下TF5池火燃烧的主要过程.     

Mass flows of endocrine disruptors in the Glatt River during varying weather conditions

This study focused on the occurrence and behaviour in wastewater and surface waters of several phenolic endocrine disrupting compounds (EDCs) including parabens, alkylphenolic compounds, phenylphenol (PhP) and bisphenol A (BPA). Analytical procedures using solid-phase-extraction and LC-MS/MS techniques were applied to samples of influents and effluents of wastewater treatment plants (WWTPs) discharging into the Glatt River (Switzerland) as well as to river water samples. A mass flow analysis provided insight into the main sources and the fate of these contaminants during different weather conditions. Concentrations in influents were in the low μg/L range for most analytes. Removal of parabens in the WWTPs was mostly above 99%. Nonylphenol polyethoxylates (A₉PEO) removal amounted to 98%, but in some cases nonylphenoxy acetic acid (A₉PEC) or nonylphenols (NP) were formed. In effluents, concentrations were highest for the A₉PEC, A₉PEO and NP. Concentrations in river water were in the high ng/L range for alkylphenolic compounds and in the low ng/L range for BPA, PhP and the parabens. During the sampling period, in which several rain events occurred, both water flows and mass flows varied strongly. Mass flows in WWTP effluents and in the river increased with increasing water flows for most compounds indicating that higher water flows do not lead necessarily to a proportional dilution of the pollutants. Throughout the low water flow period, mass flows predicted from the known inputs were similar to the actual mass flows at the end of the river for most analytes. For none of the EDCs, significant in-stream removal could be observed. In the periods with high water flows, mass flows in the river were much higher than can be explained by the initially defined sources. Discharge of untreated wastewater influent into the river was assessed as an additional source. Adding this source improved the mass balance for some, but not all of the analytes.     

Persistent organic pollutants (POPs) in Caspian seals of unusual mortality event during 2000 and 2001

Persistent organic pollutants including organochlorine pesticides, PCBs, and PCDDs/DFs were determined in the blubber of Caspian seals, which died during an outbreak of canine distemper virus in 2000 and 2001. DDTs were the predominant contaminants that ranged from 3.1 to 560 microg/g lipid. A negative correlation was observed between concentration of contaminants and blubber thickness. During spring, as the blubber layer becomes thin after breeding and moulting, seals may face higher risk due to the increased concentration of organochlorines in their bodies. TEQs in the blubber of Caspian seals (10-340 pg TEQ/g) were lower than those in seals from other locations, suggesting that toxic effects of these contaminants are a deal less in the present population and they are unlikely to be linked to mass mortality. The levels of PCBs and pesticides in Caspian seals, however, comparable to those in other aquatic mammals that have suffered from epizootics, might pose a risk of immunosuppression.     

Mass flows and removal of antibiotics in two municipal wastewater treatment plants

The mass flows and removal of 20 antibiotics of seven classes in two wastewater treatment plants (WWTPs) of Hong Kong were investigated in different seasons of a whole year, using bihourly 24 h flow proportional composite samples. Antibiotics were detected at concentrations of 3.2-1718, 1.3-1176 and 1.1-233 ng L⁻¹ in influents, secondary and disinfection effluents. Total daily discharges of all the detected antibiotics from effluents of Shatin and Stanley WWTPs were 470-710 and 3.0-5.2 g d⁻¹, respectively. Ampicillin, cefalexin, sulfamethoxazole, sulfadiazine, sulfamethazine, chlortetracycline and vancomycin were effectively (52-100%) eliminated by activated sludge process while ampicillin and cefalexin were effectively (91-99%) eliminated by disinfection. Bihourly variation analysis showed that concentrations of the major antibiotics in influents varied more significantly in Stanley WWTP which served small communities.