System dynamics model for analyzing effects of eco-design policy on packaging waste management system

EU's long-term objective is to become a recycling and resource effective society, where waste is utilized as a resource and waste generation is prevented. A system dynamics model was developed to analyze the policy mechanisms that promote packaging material efficiency in products through increased recycling rates. The model includes economic incentives such as packaging and landfill taxes combined with market mechanisms, behavioral aspects and ecological considerations in terms of material efficiency (the packaging material per product unit, recycled fraction in products). The paper presents the results of application of various policy instruments for increasing packaging material efficiency and recovery rate and reducing landfilled fraction. The results show that a packaging tax is an effective policy instrument for increasing the material efficiency. It ensures the decrease of the total consumption of materials and subsequent waste generation. The tax helps to counteract a rebound effect, which, as identified by the analysis, can be caused by reduced material costs due to eco-design. The model is applied to the case of Latvia. Yet, the elements and structure of the model developed are similar to waste management systems in many countries. By changing numeric values of certain parameters, the model can be applied to analyze policy mechanisms in other countries.     

秸秆还田下氮肥用量对玉米产量及土壤无机氮的影响

研究连续2年秸秆还田下氮肥用量对玉米产量、氮肥利用率及土壤硝态氮的影响,结果表明,玉米产量随着施氮量的增加逐渐增加,施氮量达到216 kg·hm^-2时,产量最高,施氮量超过216 kg·hm^-2时产量有降低的趋势。相同施氮处理玉米产量年际变化明显,2010年较2009年产量提高0.69％~4.75％。氮肥利用率、氮肥农学利用率和氮收获指数随着秸秆还田年限的增加,均有不同程度的增加。2年0~100 cm土层土壤硝态氮含量均以施氮240 kg·hm^-2最高,且有向土壤深层迁移的趋势,对浅层地下水构成潜在的威胁。与施氮240 kg·hm^-2相比,施氮168、192 kg·hm^-2和216 kg·hm^-2处理0~100 cm土壤无机氮残留量2年平均减少39.87％、35.84％和29.38％。相同施氮处理,0~100 cm土壤无机氮累积量2010年较2009年略有降低。综合考虑玉米产量、氮肥利用率与生态环境效益,该地区最适施氮量200 kg·hm^-2左右。     

我国燃油税改革效应模拟分析

经历了十几年的讨论,燃油税改革方案终于在2009年出台并实施,改革后燃油税究竟会对我国宏观经济及各部门产生怎样的影响,倍受关注.基于此背景,采用环境CGE模型对改革前后的两种不同燃油税税率进行了量化分析,总体研究得出：从长期发展来看,燃油税改革有利于我国经济结构调整,减少能源消耗和降低碳排放;短期内会增加企业生产成本,抑制宏观经济增长,其中交通运输业和石油加工业受到的冲击最大,应引起有关部门重视.     

The Convergence Analysis on the Economic Growth and Energy Intensity Gap between Regional Sectors

In this paper,the authors have analyzed the relationship between energy intensity gap and GDP per worker gap of China’s western and eastern provinces over the period 1997-2006.Using panel data model with lag adjustment,taking the above provinces and six industrial sectors (agriculture,forestry,animal husbandry,and fisheries,industry,construction industry,transport,storage and post & telecommunications,wholesale and retail trades & catering industry,and other sectors of tertiary industry.) as the investigated subjects,the authors have conducted empirical study on the convergence of GDP per worker gap and the convergence of energy intensity gap with respect to the variation of GDP per worker gap,and have concluded that:First,the GDP per worker gap of the six industrial sectors and provinces are convergent,and of this,the convergence rate of GDP per worker gap of Construction Industry is the fastest,while that of Industry is the slowest.Second,the overall energy intensity gap between eastern and western provinces is convergent,that is,with the narrowing of GDP per worker gap between eastern and western provinces,the energy intensity gap converges,but its convergence rate is slower than that of GDP per worker gap.Third,energy intensity gap between various industrial sectors of the east and the west is either convergent or divergent,and there are differences.The energy intensity gap of agriculture,forestry,animal husbandry,and fisheries,industry,and construction industry is convergent,while that of the other three industrial sectors is divergent.Fourth,the convergence of the overall energy intensity of the western provinces is not in conformity with the convergence of the various industrial sectors,and there are significant differences,indicating that the western provinces and autonomous regions should take measures to more effectively improve their overall energy utilization efficiency at the industrial sector level.     

能源强度收敛:对发达国家与发展中国家的检验

能源强度是指一个国家或地区生产单位产值所消耗的能源量,它反映了经济系统对能源的依赖程度和能源的使用效率。许多国家的能源强度曲线在直观上表现出收敛的显著特征。为了对这一现象进行严格的证明和检验,该文依据时间序列协整概念,首先提出了能源强度收敛的定义,然后从一个包含能源投入的内生增长模型出发,从理论上证实了能源强度收敛的存在性。为了对能源强度收敛进行实证检验,选取24个国家,并划分组合为5组样本,分别对能源强度收敛进行了σ收敛检验和协整检验,结果表明:高收入国家、高中收入国家、中低收入国家、发展中国家和样本中所有国家都存在能源强度收敛现象;σ收敛检验还揭示出各组样本中能源强度收敛的时间段以及收敛程度的大小排序。     

基于生物质能的芒属（Miscanthus）植物碳动态和收支研究进展

生物质能（Biomass energy）是最为广泛的可再生能源，其中多年生芒属C4植物（Miscanthus）由于具有巨大碳固定能力而成为潜力巨大的生物质能植物。中国是芒属植物芒草起源中心，但相对于欧洲国家应对能源危机和温室效应而采取的芒草研究与应用来说，仍处于起步阶段。我国长期以来传统的草地利用模式，决定了在南方草地的研究显著少于北方，近年来芒草在华南地区的运用研究集中于生态修复，对草本植物群落基于生态系统水平的 CO2气体交换能力的研究仍然相当缺乏，在二氧化碳浓度持续增长及全球变暖背景下，生物质能植物及其碳汇功能的相关研究尤显重要。我国南方近6700万hm2退化丘陵草坡急待恢复或处于恢复中，草坡地芒属植物符合生物质能植物标准，施肥少，害虫少，农药输入少，能够有效地利用光、水等自然资源。考虑到C4植物具有比C3植物更强的光合作用能力，高光能利用率C4芒属植物的碳固定能力及能源潜力值得重视，但缺乏科学的碳动态和碳收支评估。综述了国内外芒草生物量特征与生物质能潜力研究现状，重点论述芒属植物生态系统水平的碳动态和收支能力研究，探讨了系统水平更客观评估芒属碳源汇（Carbon sequestration）功能的方法，基于生物量过程的研究结果及华南地区草坡研究历史和现状，为草坡地生物质能的合理开发利用提出了相关对策，强调在我国南方开发和利用芒属植物资源具有重要能源价值和经济、环境效益。     

北京兰天热能系统工程探讨

文章通过综合分析、计算 ,提出用天然气代替煤作主要能源 ,走燃机热电联供道路 ,解决北京市大气环境恶化的问题 ,并对这一工程方案实施的可能性和优越性作了阐述 ,最后提出了多项实施建议。     

城市煤气输配过程中的变频调速自动恒压控制系统

将河南平顶山煤气公司原煤气输配系统改造成为自动恒压控制系统,从而提高安全系数,降低煤气输配电耗。     

Comparison of a two-stage sampling design and its composite sample alternative: An application to soil studies

The objective of a long-term soil survey is to determine the mean concentrations of several chemical parameters for the pre-defined soil layers and to compare them with the corresponding values in the past. A two-stage random sampling procedure is used to achieve this goal. In the first step, n subplots are selected from N subplots by simple random sampling without replacement; in the second step, m sampling sites are chosen within each of the n selected subplots. Thus n · m soil samples are collected for each soil layer. The idea of the composite sample design comes from the challenge of reducing very expensive laboratory analyses: m laboratory samples from one subplot and one soil layer are physically mixed to form a composite sample. From each of the n selected subplots, one composite sample per soil layer is analyzed in the laboratory, thus n per soil layer in total. In this paper we show that the cost is reduced by the factor m — 1 when instead of the two-stage sampling its composite sample alternative is used; however, the variance of the composite sample mean is increased. In the case of positive intraclass correlation the increase is less than 12.5%; in the case of negative intraclass correlation the increase depends on the properties of the variable as well. For the univariate case we derive the optimal number of subplots and sampling sites. A case study is discussed at the end.     

Evaluation of Saccharomyces cerevisiae strains as probiotic agent with aflatoxin B1 adsorption ability for use in poultry feedstuffs

In this study the aflatoxin B₁ (AFB₁) removal capacity, the tolerance to salivary and gastrointestinal conditions, autoaggregation and coaggregation with pathogenic bacteria of Saccharomyces cerevisiae strains isolated from broiler feces, were evaluated. Only four of twelve isolated strains were identified as Saccharomyces cerevisiae using molecular techniques. The results obtained in AFB₁ binding studies indicated that the amount of AFB₁ removed was both strain and mycotoxin-concentration dependent. Therefore, a theoretical model was applied in order to select the most efficient strain to remove AFB₁ in a wide range of mycotoxin concentration. The results indicated that S. cerevisiae 08 and S. cerevisiae 01 strains were the most efficient microorganisms in the mycotoxin removal. Viability on simulated salivary and gastrointestinal conditions was investigated and S. cerevisiae 08 strain showed the best results, achieving 98% of total survival whereas S. cerevisiae 01 reached only 75%. Autoaggregation and coaggregation assays showed S. cerevisiae 08 as the most appropriate strain, mainly because it was the unique strain able to coaggregate with the four bacterial pathogens assayed. Consequently, S. cerevisiae 08 is the best candidate for future in vivo studies useful to prevent aflatoxicosis. Further quantitative in vitro and in vivo studies are required to evaluate the real impact of yeast-binding activity on the bioavailability of AFB₁ in poultry. However, this study could be useful in selecting efficient strains in terms of AFB₁ binding and provide an important contribution to research into microorganisms with potential probiotic effects on the host.