铝合金材料腐蚀形貌及裂纹扩展分析

通过加速腐蚀试验,利用QUESTAR三维光学显微镜观察,将蚀坑看作是椭球形,其深度及宽度都符合幂函数的形式,都随腐蚀时间的增加而增加,但增加的速率都降低;腐蚀能显著降低试件的疲劳寿命,是疲劳裂纹形成的主要原因;AFGROW软件较好地拟合了腐蚀试件的裂纹扩展寿命,拟合误差较低,且所得的裂纹扩展寿命及临界裂纹长度比实际试验...     

Software as a bridge between theory and practice in life cycle assessment

Three mutually dependent elements are required for the application of life cycle assessment: methodology, data and software. Obviously, the design of software is determined by the methodology and the type of data available. Conversely, the development of software dictates the way in which data should be collected and recorded, and improves the theoretical framework, as it forces one to state the principles clearly and unambiguously. The influence of the development of software on both data and methodology is addressed and illustrated by examples, with reference to two key terms: transparency and explicitness. Three types of influence are distinguished: the design of a protocol, the formulation in terms of recipes, and the presentation of data.     

生命周期评价数据库分析与建模

基于关系数据库和面向对象程序设计理论建立了生命周期评价数据库系统。通过综合分析生命周期评价数据，根据生命周期评价数据的数据类型，将数据分为产品评价数据、产品档案数据、基础材料数据和影响评价基础数据，相应的设计了4个数据库。运用关系数据库理论分别对4个数据库建立了物理结构模型。     

电袋复合除尘器中产生氧化性物质的研究

针对电袋复合除尘器前级电场电晕放电有可能会产生臭氧,而臭氧又迅速与烟气中NO反应生成NO2这一猜想,通过对实际工况下电袋复合除尘器中臭氧含量和NOX浓度进行的测试,得出电袋复合除尘器中并无臭氧产生,且NO2浓度也未增加。但烟气中NO2浓度已经接近除尘器PPS滤料在使用温度下(150℃)所能承受的最高限值,PPS滤料会因发生氧化而失效,缩短滤料使用寿命。     

天然气管道失效个人生命风险评价技术研究

为研究天然气长输管道失效个人生命风险,提出一种以人员伤亡概率为指标的天然气管道失效后果风险评价方法。基于天然气管道的失效概率和失效致死长度参数,建立天然气长输管道生命风险评价模型。用该模型,对国内某城市住宅小区内带腐蚀缺陷的天然气管线进行定量风险分析。借鉴英国天然气输送公司数据,确定天然气管线个人生命风险值。案例证明,用所建立的天然气管道失效个人生命风险评价模型能够有效地分析带缺陷天然气管道失效后果,实现天然气管道的个人安全生命风险全定量评价。     

基于Matlab的火灾探测报警系统可靠度Monte Carlo仿真

介绍了火灾探测报警系统的结构,指出了火灾探测报警系统失效原因,针对火灾探测报警系统的特点,确定了蒙特卡洛可靠度分析法.给出了系统的概率模型,确定了在Matlab下应用Monte Carlo方法对火灾探测报警系统的可靠度进行仿真的具体步骤,得到火灾探测报警系统可靠度仿真曲线.将仿真结果与试验结果相比较,基本一致,验证了该仿真方法能正确描述火灾探测报警系统的可靠度随使用寿命的变化规律,为进一步应用该方法来分析火灾探测报警系统的的各可靠性指标提供了理论基础.     

Benefits and challenges of streamlined life-cycle assessment for SMEs – findings from case studies on climate change impacts

ABSTRACT

Small and medium-sized enterprises (SMEs) have a substantial role in the economy and job creation, but they are a remarkable source of environmental impacts. SMEs often lack skills and resources to compile environmental impact assessments; Streamlined Life Cycle Analysis (LCA) can provide efficient tools for this. An application of streamlined LCA relying heavily on database data, LCA clinic, was developed and tested on 23 SMEs in Finland. The climate change impacts were mainly caused by the production of raw materials, electricity and heating, whereas packaging and transportation were not influential. A significant amount of emissions were indirect, i.e. caused by production of raw materials. Thus, decreasing emissions from raw material production or selecting raw materials with a smaller environmental load could be a more efficient way to decrease emissions than reducing direct emissions such as those from electricity use. Lack of data in the LCA-databases was considered a challenge. An access to regionally customised datasets is important for the implementation of LCA clinics. Company feedback indicated that LCA clinics were useful in climate-friendly product design and increased environmental awareness, but did not lead to immediate actions to reduce emissions because of inadequate investment capabilities. Company managers had limited possibilities to use the results in marketing as comparative assessments would require a full LCA. Many company managers were willing to pay a fee sufficient to cover the costs of an LCA clinic, but some considered that the costs should be covered by external funding sources.     

浅丘河道生态需水量计算方法对比研究——以鄂北地区水河为例

适宜的生态需水量是保障河道生态系统健康的重要因素,合理地计算生态需水量对河道生态系统评估具有现实意义。以鄂北地区典型浅丘河道——水河为例,基于Qp法(不同频率最枯月平均值法)、频率曲线法、最小月平均流量法、Tennant法及生物习性法5种方法的生态流量计算结果,探讨了各方法计算结果的合理性与适用性。结果表明:由于上下游河道水文条件差异性,上游断面采用生物习性法能较好地拟合河道水文节律变化和水质波动;同理,下游断面采用频率曲线法更加匹配下游河道水文、水质情况。因此,在河道上、下游断面分别采用生物习性法、频率曲线法计算得到适宜生态需水量为0.21 m^3/s、2.02 m^3/s。     

Meta-analysis of the differential effects of habitat fragmentation and degradation on plant genetic diversity

Genetic diversity is a key factor for population survival and evolution. However, anthropogenic habitat disturbance can erode it, making populations more prone to extinction. Aiming to assess the global effects of habitat disturbance on plant genetic variation, we conducted a meta-analysis based on 92 case studies obtained from published literature. We compared the effects of habitat fragmentation and degradation on plant allelic richness and gene diversity (equivalent to expected heterozygosity) and tested whether such changes are sensitive to different life-forms, life spans, mating systems, and commonness. Anthropogenic disturbance had a negative effect on allelic richness, but not on gene diversity. Habitat fragmentation had a negative effect on genetic variation, whereas habitat degradation had no effect. When we examined the individual effects in fragmented habitats, allelic richness and gene diversity decreased, but this decrease was strongly dependent on certain plant traits. Specifically, common long-lived trees and self-incompatible species were more susceptible to allelic richness loss. Conversely, gene diversity decreased in common short-lived species (herbs) with self-compatible reproduction. In a wider geographical context, tropical plant communities were more sensitive to allelic richness loss, whereas temperate plant communities were more sensitive to gene diversity loss. Our synthesis showed complex responses to habitat disturbance among plant species. In many cases, the absence of effects could be the result of the time elapsed since the disturbance event or reproductive systems favoring self-pollination, but attention must be paid to those plant species that are more susceptible to losing genetic diversity, and appropriate conservation should be actions taken.