A multi-path routing-inventory problem for a closed-loop supply chain considering the heterogeneous fleet of vehicles

In this paper, the inventory-routing problem is studied for a closed-loop supply chain. This closed-loop supply chain considers suppliers, manufacturers, whole-sellers, and disposal centers. To formulate this problem, a mixed integer linear programming model is proposed. This mathematical model minimizes the total costs of the supply chain, including the fixed and variable costs of vehicles, and holding inventory costs of final products and scraps. The proposed model considers the road roughness degree, multi-path setting and the heterogeneous fleet of vehicles, which increases its flexibility and the quality of solutions. Then, two symmetry-breaking constraints are proposed to reduce the complexity of the mathematical model. In order to evaluate the integrity of the proposed model, 20 instances of different sizes are randomly generated and solved. Finally, a comprehensive sensitivity analysis is conducted with respect to five key features of the problem, such as the impact of the symmetry-breaking constraints on the CPU time, multi-path setting, fixed cost of vehicles, heterogeneous fleet of vehicles, and lost sales. The results indicate that the consideration of multi-path setting and the heterogeneous fleet of vehicles improves the quality of solutions significantly.     

图书馆书库清点方法初探

图书馆藏书大多存在实物与财产登记不符的状况，如情况较为严重则会影响到图书馆流通、采访等项工作的开展，因此适时进行书库清点具有重要意义。本文以中国环境管理干部学院图书馆的清点为实例，初步探讨了将条码作为清点切入点的书库清点工作的方法、步骤和注意事项。     

北京市农业机械排放因子与排放清单

利用车载排放测试技术对典型的联合收割机、拖拉机、农用运输车和农田建设机械实际工况下的尾气进行测试,建立了实际工况下农业机械的排放因子和2017年北京市农用机械排放清单.结果表明,不同的工作状态对农业机械尾气排放有较大的影响,怠速和行走时CO、NO_x、HC和PM排放趋于平稳;而切地和翻地模式下的波动较为明显.根据各类机械的分类和排放标准对排放因子进行细化,建立了较为完整的实际工况下的排放因子.根据农业机械排放因子和燃油消耗量计算出2017年北京市CO、NO_x、HC和PM的排放量分别是2 566.60、 1 239.29、 563.08和538.32 t.拖拉机、运输机械和联合收割机的污染物总量占CO、NO_x、HC和PM这4种污染物总量的98%、 95%、 95%和98%.因此,农用拖拉机、运输机械和联合收割机在农业机械污染减排中应作为重点控制对象.     

上海地区大气中氯化氢和颗粒氯排放源清单初步研究

氯自由基对于臭氧和二次气溶胶的生成贡献不容忽视.夜间颗粒相氯(Cl~-)可以通过与N_2O_5的复杂反应转化生成ClNO_2,其光解产生的氯自由基将显著影响大气污染的形成机制.本文以上海地区为案例,以2017年为基准年,收集了人为源活动水平数据,采用排放系数估算方法,首次建立了上海地区人为源氯化氢(HCl)和颗粒氯(Cl~-)的排放清单;并进一步结合模型计算海盐气溶胶排放的颗粒氯(Cl~-).结果表明,2017年上海市人为源和天然源排放的HCl和Cl~-分别为1207 t和820 t,其中,燃煤、工业、垃圾焚烧和秸秆燃烧产生的HCl排放量分别为327、134、722和24 t.燃煤源中的燃煤电厂和其它行业燃烧约占燃煤源排放的80%;工业源中水泥为HCl的最大排放源,约占工业源排放的51%;垃圾焚烧厂排放约占总HCl排放的60%,为最大的HCl排放源.燃煤、工业源、垃圾焚烧、秸秆焚烧、烹饪源和海盐的颗粒Cl~-排放量分别为82、153、498、47、39和0.6 t,燃煤源中的燃煤电厂占燃煤Cl~-排放的40%,供热、其他行业和家庭燃烧分别占燃煤Cl~-排放的24%、22%和14%;钢铁行业为工业源的主要Cl~-排放源,约占工业源排放的90%,垃圾焚烧厂占全部Cl~-排放的61%,烹饪源中餐饮企业为最主要排放源,占烹饪源的70%;天然源海盐的排放量极少,未占到总排放的1%.从空间分布来看,浦东新区、宝山、普陀、松江和金山排放的HCl和Cl~-占到全市人为源总排放的80%,为主要的HCl和Cl~-排放区域.本文研究建立的上海地区大气中氯化氢和颗粒氯排放源清单,对于深入研究氯化学机制对二次污染的影响提供了重要的数据参考.     

Reviews of emission of biogenic volatile organic compounds (BVOCs) in Asia

Biogenic volatile organic compounds (BVOCs) in the atmosphere play important roles in the formation of ground-level ozone and secondary organic aerosol (SOA) in global scale and also in regional scale under some condition due to their large amount and relatively higher reactivity. In places with high plant cover in the tropics and in China where air pollution is serious, the effect of BVOCs on ozone and secondary organic aerosols is strong. The present research aims to provide a comprehensive review about the emission rate, emission inventory, research methods, the influencing factors of BVOCs emissions, as well as their impacts on atmospheric environment quality and human health in recent years in Asia based on the summary and analysis of literatures. It is suggested to use field direct measurement method to obtain the emission rate and model method to calculate the emission amount. Several recommendations are given for future investigation and policy development on BVOCs emission.     

贵州草海湿地溶解性有机物的光谱特征及其与PFASs的相关性分析

为描述草海湿地DOM（dissolved organic matter,溶解性有机物）荧光特征,探究其对PFASs（per-and polyfluoroalkyl substances,全氟及多氟化合物）环境行为造成的影响,利用超高效液相色谱-质谱联用技术和三维荧光光谱技术,结合平行因子分析,开展DOM光谱学特性研究,分析ρ（DOM）与ρ（PFASs）的相关关系.结果表明:①草海湿地中共解析出3类4种荧光组分,分别为类腐殖酸[λ_Ex（360 nm）/λ_Em（450 nm）]、长波段腐殖质[λ_Ex（400 nm）/λ_Em（510 nm）]、类富里酸[λ_Ex（330 nm）/λ_Em（400 nm）]和类色氨酸[λ_Ex（280 nm）/λ_Em（350 nm）],贡献率分别为48.6%、23.6%、22.9%和4.9%,其中类腐殖质总贡献率高达72.2%.在农业生产和人类活动的影响下,总荧光强度大致呈现从入湖区向出湖区逐渐降低、湖心区略高的趋势.②在草海湿地表层水中共检出了12种PFASs,ρ（PFASs）为233.18 ng/L,每种平均值为19.43 ng/L,PFBA（perfluorobutanoic acid,全氟丁酸）是主要污染物;草海湿地入湖区点源影响特征明显,生活污水和农业生产用水是主要的潜在污染源.③相关性分析结果显示,各荧光组分含量均与ρ（PFBS）（potassium perfluorobutanesulfonate,全氟丁烷磺酸）负相关;类色氨酸含量与ρ（PFHpA）（perfluororoheptanoic acid,全氟庚酸）负相关,与ρ（PFTriDA）（perfluorotrideanoic acid,全氟十三酸）则显著正相关.研究显示,草海湿地水体腐殖化程度高,外源特征明显,共检出12种PFASs,初步揭示了草海湿地水环境中ρ（DOM）与ρ（PFASs）的相关关系,其受水体性质及化合物结构等差异的影响,有待进一步开展深入研究.      

郑州市VOCs组分排放清单及其臭氧生成潜势

基于人为源挥发性有机物（VOCs）活动水平统计和源成分谱梳理,采用排放因子法,建立了郑州市2016年VOCs组分排放清单,评估了各类源臭氧生成潜势（OFP）.结果表明,2016年郑州市人为源VOCs排放总量为96215.3 t,排放量最高的是道路移动源（29.7%）,其次是有机溶剂使用源（28.1%）;排放量最高的组分是烷烃（29.8%）,其次是芳香烃（29.0%）.郑州市人为源VOCs的OFP为341291.0 t,贡献最高的排放源是道路移动源（30.5%）,其次是溶剂使用源（28.8%）,其中轻型汽油车、内墙涂料使用、机动车表面涂层、加油站装卸油和非金属矿物制造是OFP的主要次级排放源,也是郑州市降低臭氧污染时需重点管控的VOCs排放源.对于VOCs种类而言,贡献较高的是芳香烃（42.8%）,其次是烯烃（38.9%）,未来应加强对间/对-二甲苯、丙烯和乙烯等物种排放来源的控制.     

基于高精度清单的京津冀机动车控污政策研究

为研究京津冀机动车污染控制政策对CO、HC、NO_x、PM_2.5、PM₁₀等污染物的减排效果,建立了2014年高精度机动车排放清单,选取过去已经实施,未来规划实施及优化/劣化后的若干政策,设置4类共13种政策情景,与实际清单基准情景进行对比,识别各政策情景的排放变化,并对其中由政府给予补贴的政策进行成本收益核算.结果显示,淘汰低排放标准机动车带来的污染减排效果最好,在天津和河北对CO和HC的排放削减分别为53.19%,49.75%和51.28%,50.87%,达半数及以上;升级机动车发动机和燃油标准也能显著削减排放,在天津和河北对PM_2.5、PM₁₀的削减分别为17.01%,17.00%和21.95%,21.93%.政府补贴政策存在明显边际效应特征,排放标准高,重污染车少的北京单位成本的减排收益明显低于天津和河北,.河北和天津在考虑成本因素的基础上,应当逐步采纳北京的高标准减排政策;北京则可在一定条件下,将一部分低效的政府补贴通过合理方式转移支付给天津和河北,以提高政府投入的减排效率.     

上海市机动车污染实时排放预警系统设计与应用

研究上海市机动车污染的动态排放测算和网格化动态排放清单构建,在实时的交通数据和交通环境监测数据的基础上,结合交通模型、机动车排放清单模型等业务模型和算法,依托大数据存储、可视化和GIS等技术,开发了上海市机动车污染物实时排放预警系统,实现了上海市全市道路的机动车动态排放测算、交通环境政策实施情景模拟和网格化排放清单,更新频率为每30 min一次,包含PM、NOx、CO、SO2、VOCs等污染物和9种车型。系统建成后直接服务于首届中国国际进口博览会,为大气污染排放实时总量跟踪评估、污染源管控措施分析及监测成因分析等提供了有力的实时数据和技术支撑。     

Forest Area in Costa Rica: A Comparative Study of Tropical Forest Cover Estimates over Time

Forest area figures, at a given point in time and for a given region of interest, differ considerably, affecting the calculation of deforestation rates and thus confuse the political and scientific discussion on the state and change of the resource forest. This article discusses the variation of published forest cover figures, using Costa Rica as an example. A list of published figures on the forest cover of Costa Rica from 1940 onwards is analyzed. Reasons for the differences are hypothesized and discussed. These differences are mainly in the definition of forest and forest classes included, in the type of the studies conducted (mapping and/or sampling), in the precision of the estimates, and in the information sources used. It is concluded that part of the problem is inherent in the nature of the resource `forest'. Quality and completeness of the presentation of the forest cover estimates are a clue to their correct understanding and interpretation. The latter point being especially relevant, as forest cover data have both a technical-scientific and a political meaning and are used as relevant arguments in many discussions. In the example of Costa Rica, a general downward trend is observed up to about 1985/1990, whereas after that forest area figures are on the average at a markedly higher level. Some hypotheses for this change in the trend are discussed.