基于模糊数学的重庆地区雷电灾害风险评估方法研究

科学合理的雷电灾害风险评估能有效指导防雷减灾工作,不过目前雷电风险评估体系尚不完善,在某些时候不能真实地评价项目的雷电灾害风险,比如在评估大型住宅小区、大面积的厂房等时,现有的评估结果不能准确地反映客观风险。在深入研究雷电成灾机制和重庆雷电活动规律的基础上,利用模糊数学理论,通过致灾因子、暴露性和承灾体易损性三个方面进行分析,提出重庆地区的雷电风险评估方法。通过具体的评估验证,该方法有较好的适用性,能更好地为防雷减灾服务,也能完善现有的雷电灾害风险评估体系。     

贵阳市西郊水厂所供管网末梢水重金属污染物季节性特征及潜在健康风险评价

以贵阳市西郊水厂2014年3月和7月所供管网末梢水中10种重金属污染物检测数据为基础,进行了季节性特征分析,并采用美国环保局(USEPA)推荐的健康风险评价模型进行了潜在健康风险评价。结果表明,贵阳市西郊水厂所供管网末梢水中10种重金属的浓度均符合国家饮用水卫生标准;重金属污染物的浓度随季节呈现出不同的特征,汞、锌、硒、钼和钡5种重金属的平均浓度呈现枯水期高于丰水期的特征,而铅、铜、锰和镍4种重金属正好相反,砷浓度的季节性特征不显著;成年人的年平均致癌风险显著大于儿童,但两者年平均非致癌风险接近;儿童和成年人2类人群经口暴露途径的健康风险值均大于皮肤暴露,其中致癌风险分别在2.49×10-6~9.16×10-6和3.26×10-8~9.59×10-8之间,非致癌风险在2.29×10-8~3.20×10-8和1.85×10-10~4.14×10-10之间,且致癌风险均大于非致癌风险。贵阳市西郊水厂所供管网末梢水中10种重金属污染物致癌风险和非致癌风险均未超过最大可接受水平,未对该供水区居民的健康造成威胁。     

Frequency Control Characteristics of a Direct-Mode Untreated Sewage Source Heat Pump in the Heating Mode

An untreated sewage source heat pump system directly makes use of the urban raw sewage instead of that treated by a sewage plant. At present In China, most systems adopt the indirect mode for avoiding the harmful effect of the sewage on the heat pump unit. In this article a direct-mode untreated sewage source heat pump system, which shows less theoretical analysis of the mathematical model, is theoretically designed and analyzed to simulate the system dynamic characteristics in the heating mode. The results show that the system COP changes from 4.1 to 3.4 and the heating capacity from 9.5 to 15.3 kW when the sewage inlet temperature is 12°C and the frequency increases from 18 to 32 HZ. The condenser heat-transfer coefficient increases with the frequency reducing while the change trend of evaporator heat-transfer coefficient is the opposite. The highest values of them are 303 and 1617 W.m^?2?K^?1, respectively. The frequency control simulation supplies the operation adjustment with theoretical instructions and some reference values.     

温岭“6‧13”液化石油气槽罐车爆炸事故灾害效应分析∗

为了揭示浙江温岭“6?13”液化石油气(LPG)槽罐车特大爆炸事故的成灾机制和破坏威力,通过事故现场实地勘察并收集公开资料,发现此次事故的两次主要爆炸分别为沸腾液体扩展蒸汽爆炸(BLEVE)和蒸气云爆炸 (VCE);分别采用 BLEVE 热辐射模型、能量法和 Jarrett 模型对两次爆炸进行了爆炸威力和灾害效应分析。结果表明：BLEVE 事故中参与火球燃烧的 LPG 约为 7.59 t,火球热辐射死亡半径、重伤半径、轻伤半径分别为 93、124 和 200 m;BLEVE 的爆炸威力相当于 88.4 kg TNT 炸药;BLEVE 冲击波作用下人员的死亡半径和安全半径分别为 9.5 和 23.6 m,建筑物的安全半径为 55 m;VCE 事故的爆炸威力相当于 10.7 t TNT 炸药;参与 VCE 反应的 LPG 约为 1.05 t;通过 Braker 评估模型计算出的 VCE 事故中人员安全半径和死亡半径分别为 221 和 84 m,钢筋混凝土结构倒塌(严重损毁)半径为 94 m,瓦片掉落、钢筋混凝土墙产生裂缝对应的计算半径为 136 m,窗框的损坏半径为 273 m,建筑物的安全半径为 700 m,计算结果与实际破坏情况吻合较好。     

2009年夏季黄山云雾水化学特征及来源分析

利用09年夏季在黄山光明顶气象站采集的25个云雾水样本及气象站常规资料,分析了云雾过程雾水的化学特征、污染来源与微物理特性.结果表明,观测期间云雾水呈弱酸性,平均值pH值为6.4,主要的离子浓度由大到小排列为:SO42->NH4+>Ca2+>NO3->Na+>Cl-,表明二次污染物对黄山云雾水的贡献较大.统计分析显示,各云雾过程中雾水组分变化,主要缘于不同云雾过程中污染源与海洋源的贡献率不同.结合后向轨迹进一步分析显示,影响气团主要来源于海洋和周边地区,不同气团影响下雾水离子组分及云雾微物理特征差别明显.     

基于参数实测的水中重金属暴露的健康风险研究

以位于长江和淮河流域交界处河南泌阳县为研究区,利用ICP/MS分析城镇和农村居民饮用水中14种重金属含量,抽样选取2 500名城镇和农村不同性别和年龄的受试者作为研究对象,详细记录受试者3 d内的饮水和皮肤接触水的活动频率,并对有关饮水和皮肤暴露参数进行了测量.用暴露和健康风险模型计算了城镇和农村居民对14种重金属的经...     

北京及周边地区大气羰基化合物的时空分布特征初探

利用2,4-二硝基苯肼（DNPH）/HPLC方法,于2010年6月24日、7月22日、8月24日、9月14日（夏季）和2011年1月13日（冬季）,在北京及周边地区38个采样点组织5次同步观测,测定了大气中23种羰基化合物的浓度水平.观测结果表明,北京市各类站点夏季和冬季的总羰基化合物体积分数分别为（16.38±6.03）×10-9,（8.50±5.27）×10-9;周边城市夏季和冬季的体积分数分别为（13.19±5.71）×10-9,（13.05±2.44）×10-9.区域大气中最主要的羰基化合物是甲醛、乙醛和丙酮,三者约占总羰基化合物浓度的78%～91%.夏季羰基化合物的浓度水平明显高于冬季,并且上午09：00～12：00时段的浓度高于下午13：00～16：00时段的浓度.在空间分布上,北京市夏季羰基化合物的高值区主要集中在交通密集的主城区,而冬季受西北风影响呈现由西北向东南递增的趋势.夏季,机动车尾气对大气羰基化合物有显著的一次和二次贡献,同时在不利的气象条件影响下,造成城市地区羰基化合物的污染现象.冬季,大气羰基化合物以一次排放为主,燃煤和机动车可能是主要的污染源.     

Effect of chlorine content of chlorophenols on their adsorption by mesoporous SBA-15

Studies on the effect of the chlorine content of chlorophenols (CPs) on their adsorption from aqueous solution by mesoporous SBA-15 are important in understanding the mechanisms of CP adsorption. In this study, three CPs with different degrees of chlorine content (i.e., 2-chlorophenol, 2,6-dichlorophenol and 2,4,6-trichlorophenol) were investigated. The effects of parameters such as temperature and solution pH were studied. The results showed that CP adsorption by SBA-15 increased with increasing number of chlorine substituents and depended strongly on the temperature and solution pH. Thermodynamic parameters such as Gibbs free energy change (ΔG⁰), enthalpy change (ΔH⁰) and entropy change (ΔS⁰) were also calculated. By comparison of the adsorption coefficient of CPs with varying physical-chemical properties (size, hydrophobicity and electron density), we propose that hydrophobic interactions between CPs and the SBA-15 surface, as well as electron donor-acceptor (EDA) complexes between oxygen of the siloxane surface of SBA-15 (e^--donor) and the πup-system of the CPs (e^--acceptor), were dominant adsorption mechanisms.     

Two stages kinetics of municipal solid waste inoculation composting processes

IntroductionCompostingisanatureprocess,butmanyman inducedinnovativemeasureshavebeendevelopedtoacceleratecompostingefficiency .Variousspecializedseedinoculumshavebeenappliedforpracticalengineering(Biey ,2 0 0 0 ) .ThemicrobialfloraandthemassconcentrationofmicrobesinMSWcompostingprocessesunderlyinginoculationaredifferentinvariousstages(Lei,2 0 0 0 ;Akihito ,1998) .Atthesametime ,thelivingenvironmentofmicroorganismsisalsoincessantlychangingduetotheincreaseofmetabolizingproductionandconsumption…     

Factors affecting the distribution of microplastics in soils of China

● Microplastic (MP) abundance in soil of China was highly heterogeneous. ● MP abundance was higher near large rivers and central land affected by monsoons. ● MP abundance was correlated with longitude, mulching film, and average temperature. ● Factors suitable for predicting MP pollution using models were discussed. Microplastics (MPs) are found worldwide in high abundance, posing a potential threat to ecosystems. Despite the ubiquity of MPs in the environment, very little is known about the regional distribution of MPs and underlying factors affecting this distribution in the field, which likely include human activity, but also features of the environment itself. Here, out of a total of 1157 datapoints investigated in 53 Chinese studies, 9.68% datapoints were removed as outliers in the heterogeneity analysis. This review revealed that the abundance of MPs was highly heterogeneous. In addition, microplastic (MP) distribution maps based on China demonstrated that the highest abundance of MPs tended to occur near large rivers and central land affected by the intersection of two monsoons. The model-fitting and previous studies showed that MP abundance in China was correlated with longitude, agricultural mulching film usage per capita, temperature, and precipitation. However, due to the heterogeneity of MPs and the low matching degree between the current environmental data and the sampling points, this pattern was not as evident as reported in any single study. Factors affecting the distribution of MPs can not be captured by linear relationships alone, and systematic selection of suitable environmental factors and further model optimization are needed to explore the cause of MP pollution in soil. Overall, this review revealed an uneven distribution of MPs and serves as a reference for model prediction to assess and control plastic pollution in natural soil environments.