浮头式换热器故障树的建立

通过现场调研，运用故障树对浮头式换热器常见故障进行分析，得出浮头式换热器系统的主要故障为腐蚀导致的泄漏。从而，从设计、焊接制造、安装、操作维护等几个环节提出改进措施，为浮头式换热器的可靠性分析提供指导。     

乙炔干燥变温吸附装置安全性分析与燃爆事故预防对策

针对乙炔变温吸附装置的燃爆事故问题,采用HAZOP方法对该装置进行安全性分析,找出存在的安全隐患,提出整改措施,指出装置发生燃爆事故的可能性;又将该装置可能发生的燃爆事故作为顶上事件,利用FTA方法进行分析,得到了装置发生燃爆事故的可能原因,制定了预防发生燃爆事故的对策。通过将HAZOP和FTA分析方法结合使用,有效地识别出乙炔装置存在的隐患,降低了装置操作的危险性,预防了燃爆事故的发生,值得推广应用。     

事故树法在环境风险评价中的应用

针对吉林省板石一矿可能发生的井下透水事故,采用事故树法进行环境风险评价,确定了事故预防重点,提出了相应的防范措施和应急预案,为矿井的建设和管理提供科学依据。     

Current Trends in Plant and Animal Population Monitoring

Abstract:  Animal and plant population monitoring programs are critical for identifying species at risk, evaluating the effects of management or harvest, and tracking invasive and pest species. Nevertheless, monitoring activities are highly decentralized, which makes it difficult for researchers or conservation planners to get a good general picture of what real-world monitoring programs actually entail. We used a Web-based survey to collect information on population monitoring programs. The survey focused on basic questions about each program, including motivations for monitoring, types of data being collected, spatiotemporal design of the program, and reasons for choosing that design. We received responses from 311 people involved in monitoring of various species and used these responses to summarize ongoing monitoring efforts. We also used responses to determine whether monitoring strategies have changed over time and whether they differed among monitoring agencies. Most commonly, monitoring entailed collection of count data at multiple sites with the primary goal of detecting trends. But we also found that goals and strategies for monitoring appeared to be diversifying, that area-occupied and presence–absence approaches appeared to be gaining in popularity, and that several other promising approaches (monitoring to reduce parameter uncertainty, risk-based monitoring, and directly linking monitoring data to management decisions) have yet to become widely established. We suggest that improved communication between researchers studying monitoring designs and those who are charged with putting these designs into practice could further improve monitoring programs and better match sampling designs to the objectives of monitoring programs.     

广州城市绿地土壤特征及其对树木生长的影响

研究广州城市绿地土壤的特征,并探讨其对树木生长的影响。结果表明:广州城市绿地土壤受到不同程度的人为干扰。其中公园和大学校园树林土壤的理化性质虽有一定改变,但仍接近自然土壤的状况;行道树的土壤则过于紧实,且pH值太高,而有机质及氮、磷含量较低。这些土壤问题会对行道树的生长造成不利的影响。文中对这些存在的问题提出了一些相应的改善措施。      

Projecting population trends of endangered amphibian species in the face of uncertainty: A pattern-oriented approach

Amphibian populations have been declining worldwide for the last three decades. Determining the risk of extinction is one of the major goals of amphibian conservation, yet few quantitative models have been developed for amphibian populations. Like most rare or threatened populations, there is a paucity of life history data available for most amphibian populations. Data on the critical juvenile life stage are particularly lacking. Pattern oriented modeling (POM) has been used successfully to estimate life history parameters indirectly when critical data lacking, but has not been applied to amphibian populations. We describe a spatially explicit, individual-based, stochastic simulation model developed to project population dynamics of pond-breeding amphibian populations. We parameterized the model with life history and habitat data collected for the endangered Houston toad (Bufohoustonensis), a species for which there is a high degree of uncertainty for juvenile and adult male survival. During model evaluation, we focused on explicitly reducing this uncertainty, evaluating 16 different versions of the model that represented the range of parametric uncertainty for juvenile and adult male survival. Following POM protocol, we compared simulation results to four population-level patterns observed in the field: population size, adult sex ratio, proportion of toads returning to their natal pond, and mean maximum distance moved. Based on these comparisons, we rejected 11 of the 16 model versions. Results of the remaining versions confirmed that population persistence depends heavily on juvenile survival, and further suggested that probability of juvenile survival is likely between 0.0075 and 0.015 (previous estimates ranged from 0.003 to 0.02), and that annual male survival is near 0.15 (previous estimates ranged up to 0.43).     

遗传算法在度约束最小生成树问题中的应用

遗传算法是一类借鉴自然界生物种群“自然选择、优胜劣汰”进化过程的启发式随机搜索优化算法,具通用性好、鲁棒性强等特点,被广泛地应用于通信网络设计领域,如度约束最小生成树问题．通过讨论遗传算法在度约束最小生成树问题中的应用,并对遗传算法在应用时存在的问题和挑战提出了见解．参17．     

Soil to leaf transfer factor for the radionuclides ²²⁶Ra, ⁴⁰K, ¹³⁷Cs and ⁹⁰Sr at Kaiga region, India

Transfer factors are the most important parameters required for mathematical modeling used for environmental impact assessment of radioactive contamination in the environment. In this paper soil to leaf transfer factor for the radionuclides ⁴⁰K, ²²⁶Ra, ¹³⁷Cs and ⁹⁰Sr is estimated for Kaiga region in Karnataka state, India. Among the plants in which study is carried out, ²²⁶Ra, ⁴⁰K, ¹³⁷Cs and ⁹⁰Sr activity in leaves of herbaceous plants is higher than that of tree leaves. Soil to leaf transfer factor for ²²⁶Ra, ⁴⁰K, ¹³⁷Cs and ⁹⁰Sr was found to be in the range of 0.03-0.65, 0.32-8.04, 0.05-3.03 and 0.42-2.67 respectively.     

Long-term patterns in soil acidification due to pollution in forests of the Eastern Sudetes Mountains

Soil acidification was assessed in the Eastern Sudetes Mountains (Czech Republic) between 1941 and 2003, i.e. before and after the period of major industrial pollution (1950s-1990s). The twenty sites included in our study were distributed along a gradient of altitude ranging 1000 m. Values of pH have decreased in 80-90% of the pairs of samples after the six decades, on average by 0.7 for pH-H₂O and 0.6 for pH-KCl. Organic matter increased in the topsoil, probably reflecting a change in decomposition conditions. The most important finding is that the acidification varies along the joint gradient of altitude/tree layer composition, and displays a changing pattern in three soil horizons (A, B and C). Contrary to expectations, most acidified were soils in beech forests at lower elevations.     

Climate Warming and the Recent Treeline Shift in the European Alps: The Role of Geomorphological Factors in High-Altitude Sites

Global warming and the stronger regional temperature trends recently recorded over the European Alps have triggered several biological and physical dynamics in high-altitude environments. We defined the present treeline altitude in three valleys of a region in the western Italian Alps and reconstructed the past treeline position for the last three centuries in a nearly undisturbed site by means of a dendrochronological approach. We found that the treeline altitude in this region is mainly controlled by human impacts and geomorphological factors. The reconstruction of the altitudinal dynamics at the study site reveals that the treeline shifted upwards of 115 m over the period 1901–2000, reaching the altitude of 2505 m in 2000 and 2515 m in 2008. The recent treeline shift and the acceleration of tree colonization rates in the alpine belt can be mainly ascribed to the climatic input. However, we point out the increasing role of geomorphological factors in controlling the future treeline position and colonization patterns in high mountains.