麻疯树种子油生命周期的经济、环境与能量效率

要成为化石能源的有效替代品，生物燃料必须能提供净能量收益，能产生环境效益，具有经济效率，且在大量生产的情况下不引起粮食危机。麻疯树作为第二代生物柴油的重要原料作物，在国内得到大力推广，但实际效率尚不清楚。基于将麻疯树种子油与化石柴油直接混合使用的技术选择，利用生命周期评估法分析了麻疯树种子油生命周期的经济、环境和能量效率。结果表明：（1）在当前产量和生产技术水平下，生产和使用麻疯树种子油的财务净现值为负，要促进麻疯树种子油的生产，需要每年为种子生产者提供8817 元/hm2以上的补贴，为榨油厂商提供268 元/L的补贴；（2）生产和使用每升麻疯树种子油可减少约13 kgCO2当量的温室气体排放，固碳价值为补贴生产提供了部分经济依据，但是仅考虑种子油和固碳的价值时，生产和使用麻疯树种子油尚不具有经济可行性；（3）当仅考虑种子油的能量产出时，只有当种子产量达到795 kg/hm2以上才具有能量效率；当把树枝和果壳等所包含的生物质能计算在内时，在较低种子产量的情况下，也具有显著的能量效率。敏感性分析表明，随着麻疯树种子产量的增加，财务净现值趋于下降，但是种子油的成本下降，减排温室气体的贡献和能量效率都增加。最后，基于麻疯树种子油的生命周期分析，提出了提高经济、环境和能量效率的途径。〖     

Experimental design to study corrosion under insulation in harsh marine environments

Corrosion under insulation (CUI) is a serious issue in harsh marine environments. Corrosion damage can have catastrophic effects on health and safety, asset integrity, the environment, and productivity if it is not detected and managed early. Limited information is available for CUI in marine environments. To overcome this issue, three types of corrosion tests are proposed: Determination of the effect of environmental factors on CUI using laboratory simulation, field testing, and accelerated marine atmosphere testing for CUI. This paper describes the methodology for developing statistically significant data to evaluate CUI in harsh marine field conditions, develop an accelerated laboratory test procedure to simulate CUI, develop a model of CUI rate, and develop risk-based remaining life assessment model for assets under CUI attack.     

水力发电技术的生命周期评价

以广东省内某一小型水电站为研究对象,对其进行了较系统的生命周期评价.通过目标和范围的确定,对水电站的各子过程进行了生命周期清单分析及环境影响潜值计算.分析表明,该水电站的总能耗为2.02g/(kW·h),其中煤占主要部分,占93.92％；该水电站排放的污染物中,CO2占绝大部分(96.70％),其次是粉尘(2.75％)；水电站的建设耗材生产子过程的能耗以及污染物排放量最大,该过程的能耗占总能耗的97.00％,污染物排放量占总排放量的94.41％；与常规燃煤电厂相比,每发电10000kW·h,该水电站可节约标煤3.98t,减少排放CO29.9648t、SOx79.927kg、NOx 49.92kg、粉尘499kg,水力发电具有非常显著的节能和环保效应；该水电站每发电lkW·h的总环境影响潜值为4.31×10-6人当量,其中粉尘是最主要的环境影响因素,这是由于水泥、钢材等建设耗材在制造生产过程中产生了大量的粉尘.     

Construction of evolving models for the environmental evaluation of innovative sub-systems based on a hierarchical agglomerative clustering

This paper deals with simplifying the environmental evaluation of an innovative sub-system related to the future complex system that will include it, by using evolving generic models built on a limited number of characteristics. For a complex system range, the evolving approach of the environmental modelling aims to generate a learning dynamics, to avoid the paralysing complexity induced in design by the valuation of many components according to many impact categories. Applied to the automotive sector, dendrograms are made with results of life cycle assessments (LCA) of 17 vehicles for 4 environmental indicators and on 3 life cycle steps. In an iterative process, a limit condition threshold on the resulting relative errors aims to cluster the vehicles. First, several calculation methods of dendrograms are tested. Second, the influence of the limit condition on the models is observed. Lastly, by simulating the vehicle population increase, the modelling capacity to evolve is tested. Five vehicle characteristics are sufficient to identify a model to be equivalent to the future vehicle. While the number of clusters is increased to simplify their identification with the system characteristics, the relative error variability increases too. The generic models are stable when adding LCA's results.     

Effects of Self-Compatibility on the Distribution Range of Invasive European Plants in North America

Abstract:  Many plant species have been introduced to new continents, but only a small subset of these have become invasive. It has been predicted that self-compatible species, particularly those that do not need the services of pollinators, are more likely to establish and spread after long-distance dispersal. We tested whether this hypothesis, commonly called Baker's law, applies to 361 species that have invaded the United States from Europe. Species capable of autonomous seed production occurred in significantly more states than species requiring a pollen vector. Moreover, of the species that are not capable of autonomous seed production, self-compatible species occurred in significantly more states than those that are not self-compatible. The positive effect of autonomous seed production on the range of invasion was larger for abiotically pollinated species than for biotically pollinated species and for monocarpic species than for polycarpic species. These results support Baker's law, and we recommend that screening protocols for predicting invasiveness of species considered for introduction should include assessment of their breeding system.     

Pyrophytic Properties of the Larch Larix gmelinii in Terms of Life Strategies

The pyrophytic properties of the larch Larix gmelinii (Rupr.) Rupr. growing in the northern taiga of central Siberia have been studied. It has been found that, although the trees are highly combustible and fire resistance of tree stands is low, the species is highly pyrophytic, which allows it to retain its geographic range. At early stages of postfire successions, the larch exhibits characteristics of pyrogenic explerent and is subject to r-selection. When forest restoration is close to completion, the species passes into the patient state and acquires properties subject to K-selection.     

耕地细碎化对农户化肥使用效率的影响

在国家提倡化肥使用零增长、减量化的背景下,如何提高农户化肥使用效率变得至关重要。论文从技术效率角度衡量化肥使用效率,使用回归分析和基于R²的夏普里值分解方法考察了耕地细碎化对农户化肥使用效率的影响方向及程度。结果表明：（1）农户在化肥使用上存在着较高的技术无效率,在保持劳动力、土地等其他要素投入数量不变的情况下,约52.51%的化肥投入可以削减且不影响产出。通过提高农户对化肥的使用和管理水平完全可以做到化肥减量而作物不减产。（2）耕地细碎化对农户化肥使用效率具有显著负影响,是导致农户化肥使用效率低下的一个重要原因,能够解释农户间化肥使用效率差异12.15%,在所有决定因素中位居第四,仅次于村虚拟变量、水田比例和粮食作物种植比例。而且,在细碎化程度越高的西部地区,耕地细碎化对农户化肥使用效率差异的贡献越强。（3）农户在化肥使用效率上的差异主要源于所在村特征和包括经营规模、种植结构、土地质量、是否加入合作社等因素在内的生产经营特征的不同;而农户个体特征受集体决策影响,解释力较弱。     

薄膜体声波滤波器加速寿命评估技术研究

目的 研究薄膜体声波滤波器的加速寿命评估技术,针对XXX1001型薄膜体声波滤波器进行可靠性寿命评估。方法 根据薄膜体声波滤波器设计、结构特点,针对XXX1001型薄膜体声波滤波器典型应用环境条件下的失效模式和失效机理分析,采用环境影响分析明确寿命表征指标和相应敏感应力,以此确定合适的加速寿命方法和加速模型。结合可靠性摸底试验确定的敏感应力极限和加速模型要求,设计加速寿命试验方案,利用阿伦尼斯模型对寿命表征指标等试验数据进行评估,得到该型薄膜体声波滤波器的可靠性寿命参数。结果 确定了滤波器的寿命表征指标（插入损耗）和敏感应力（温度）,设计了加速寿命试验方案,试验实施后,根据试验数据评估出XXX1001型薄膜体声波滤波器在40 ℃工作时的平均寿命为117 803 h。结论 该技术程序较为简单、实施方便、样本少、成本低,可为类似滤波器的可靠性评估提供参考。其评估结果也可为XXX1001型薄膜体声波滤波器的设计改进和应用推广提供技术支撑。     

环境对某型飞机典型结构部位疲劳寿命影响分析

目的 研究环境对飞机典型结构部位疲劳寿命的影响。方法 选取某型机机身连接壁板、机翼壁板、机翼内部大梁结构、平尾接头及垂尾接头的典型模拟件为研究对象,开展实验室加速腐蚀与随机载荷谱交替试验、载荷谱疲劳试验,分析环境对典型结构部位模拟件表面涂层损伤、疲劳断裂位置、疲劳源及中值寿命的影响,建立环境对结构部位疲劳寿命影响关系。结果 采用载荷作用后结构部位模拟件疲劳中值寿命与加速腐蚀环境-疲劳寿命后试样的疲劳中值寿命比值,估算环境对结构部位模拟件疲劳寿命的影响,比值k=1.2~2.5,且比值k越大,说明环境对试样的疲劳寿命影响越大。结论 采用载荷作用后结构部位模拟件疲劳中值寿命与加速环境-疲劳寿命后试样的疲劳中值寿命比值,可初步估算环境对结构部位模拟件疲劳寿命的影响,且试验结果表明,外部环境较内部环境对试样疲劳寿命的影响更大。     

面向导弹延寿的冲压发动机加速贮存试验方法

目的更为真实地反映自然贮存环境对某型导弹冲压发动机寿命的影响,研究综合环境应力加速贮存试验方法。方法为了符合自然环境的年变化规律,设计1个周期的综合环境应力加速贮存试验能够等效产品自然贮存1年,每个周期的加速贮存试验包括低温冷冻、高低温交变加速、高温高湿加速、高温老化4部分。采用加速模型估计出每段加速试验的加速因子,进而依据自然贮存环境测试数据折算出加速试验谱。结果所提方法提高了冲压发动机加速贮存试验的科学性与准确性。结论研究工作为高效完成导弹冲压发动机贮存延寿任务提供了可行的工程方法。