Transport and Adhesion of Escherichia coli JM109 in Soil Aquifer Treatment (SAT): One-Dimensional Column Study

Bacteria transport and adhesion experiments under water-saturated and partially saturated conditions were examined over a wide range of ionic strength, from 1 to 100 mM KCl, CaCl₂, and MgCl₂, and at water contents of 0.15 and 0.22 in sand columns packed with three different sands, baked, sterilized, and raw sands in order to investigate the effects of ionic strength, water content, and porous media type on the microbial adhesion in soil aquifer treatment (SAT). Well-characterized Escherichia coli JM109 were used as model bacterial cells in this study. Column study results showed that bacterial deposition rates increased with increasing ionic strength and decreasing water content, and were higher in raw sand columns than those in other sand columns. The Derjaguin–Landau–Verwey–Overbeek (DLVO) theory was applied to experimental results in order to consider the interaction energies between the bacterial cells and collector grains; results revealed that a considerable amount of bacterial cells was weakly deposited onto the solid surfaces in secondary minimum.     

渗流场对地铁隧道沉降与受力影响的流固耦合分析

地下水问题是富水地层地下结构设计与施工中普遍存在的问题。为探讨地下水流动对软岩地铁隧道的稳定性及衬砌支护受力的影响,根据流固耦合理论,采用三维快速拉格朗日有限差分方法,在不同地下水位及排水边界条件下,对开挖后洞室周边场地位移、应力场、孔隙水压力的分布情况进行了综合分析。结果显示,由渗流引起的渗透力一定程度上会增加隧道周边场地变形及衬砌应力。从围岩-支护结构共同作用的原理出发,验证了隧道开挖与支护结构设计时需要考虑渗流效应,反映了地下水确实对隧道稳定性有着重要影响。     

计算机辅助HAZOP技术的研究

在HAZOP原理的基础上,讨论了计算机辅助HAZOP技术的优势,并针对传统的HAZOP、基于深层知识模型SDG的计算机辅助HAZOP和应用PHA-Pro软件3种方法进行了分析和比较;介绍了研发成功的针对开、停车过程和应急阶段顺序颠倒、操作步骤遗漏的人工误操作危险与可操作性分析系统MO-HAZOP;该系统具有定量计算出所有的人工误操作顺序组合的发生概率值,结合现有知识和专家经验,判定事件发生的风险等级,从而有重点地给出预防危险、保障生产安全的建议的功能;MO-HAZOP分析系统对于石化企业的安全生产具有重要意义。     

人因失误与人不安全行为相关原理的分析与探讨

从人因失误的机理、分类和特点等方面,对人因失误与人不安全行为间的相关原理进行系统的对比分析与探讨,笔者认为,应从安全教育、技术培训、人机系统设计等方面预防人因失误,从建立和维持操作者对安全工作的兴趣、作业标准化、安全管理等方面来控制人的不安全行为。以煤矿斜井提升事故为例,说明人因失误与人不安全行为的判定原则和方法,从而为预防、控制人因事故提供理论依据。     

浅析油气储运设施环境保护管理发展趋势

针对油气储运设施工程特点,通过比较清洁生产和循环经济的理念及侧重点,提出了全生命周期的环保管理理念,然后根据这一理念分析了我国油气储运设施工程从设计、施工到投产、运行全过程的环保管理现状和发展趋势,并提出了相应建议。     

阵性泥石流运动与堆积的欧拉-拉格朗日模型——Ⅰ.理论

自然界中的混石流具有突发性和非恒定性的特点。为了模拟典型泥石流现象,在流团模型的基础上,进一步完善了基于欧拉－拉格朗日（Ｅ－Ｌ）观点的ＰＩＣ（Ｐａｒｃｅｌ Ｉｎ Ｃｅｌｌ）算法,细化了流元结构,建立了能够模拟典型阵性泥石流发生、运动和堆积的准结构两相流模型,求解该模型不仅可以模拟泥石流运动过程,而且可以对泥石流的堆积过程、停积形态、冲刷特征及泥石流中多组分颗粒的分选特征进行定量描述。     

How Do Groups Solve Local Commons Dilemmas? Lessons from Experimental Economics in the Field

The use of experimental settings to observe human behaviour in a controlled environment of incentives, rules and institutions, has been widely used by the behavioural sciences for sometime now, particularly by psychology and economics. In most cases the subjects are college students recruited for one to two hour decision making exercises in which, depending on their choices, they earn cash averaging US$ 20. In such exercises players face a set of feasible actions, rules and incentives (payoffs) involving different forms of social exchange with other people, and that in most cases involve some kind of externalities with incomplete contracts, such as in the case of common-pool resources situations. Depending on the ecological and institutional settings, the resource users face a set of feasible levels of extraction, a set of rules regarding the control or monitoring of individual use, and sometimes ways of imposing material or non-material costs or rewards to those breaking or following the rules. We brought the experimental lab to the field and invited about two hundred users of natural resources in three Colombian rural villages to participate in such decision making exercises and through these and other research instruments we learned about the ways they solve - or fail to - tragedies of the commons with different social institutions. Further, bringing the lab to the field allowed us to explore some of the limitations of existing models about human behaviour and its consequences for designing policies for conserving ecosystems and improving social welfare.     

Wind selectivity of migratory flight departures in birds

Optimal migration theory predicts that birds minimizing the overall time of migration should adjust stopover duration with respect to the rate of fuel accumulation. Recent theoretical developments also take into account the wind situation and predict that there is a time window (a set of days) during which birds should depart when assisted by winds but will not do so if there are head winds. There is also a final day when birds will depart irrespective of wind conditions. Hence, the wind model of optimal migration theory predicts that birds should be sensitive to winds and that there should be a correlation between departures and winds blowing towards the intended migration direction. We tested this assumption by tracking the departures of radio-tagged passerines during autumn migration in southern Sweden. Our birds were moderately to very fat when released and therefore energetically ready for departure. There was a significant correlation between direction of departure and wind direction. We also found that during days when birds departed there was a significantly larger tail wind component than during days when birds were present but did not depart. Our results show that passerines do take the current wind situation into account when departing on migratory flights. We also briefly discuss possible clues that birds use when estimating wind direction and strength. The inclusion of wind is an important amendment to optimal migration theory of birds and should be explored further. Received: 1 March 1999 / Received in revised form: 4 October 1999 / Accepted: 16 October 1999     

The role of perceived government style in the facilitation of self-determined and non self-determined motivation for pro-environmental behavior

Most North Americans are concerned about the environment and feel that responsibility for its protection lies primarily with government; however, no research to date has examined the influence of the government's approach toward environmental regulation on the motivation of individual citizens. According to self-determination theory, social contexts that support one's autonomy should facilitate self-determined motivation and social contexts that thwart autonomy should lead to non self-determined motivation and a sense of apathy or amotivation. In this study (n = 283), we examined the influence of perceptions of the government's approach toward environmental regulation on motivation toward the environment and frequency of self-reported pro-environmental behavior (PEB). Using structural equation modeling, we tested the hypothesis that frequency of PEB is predicted by motivation toward the environment and that motivation is predicted by the extent to which individuals perceive the government to be autonomy-supportive versus controlling in the implementation of environmental policies. The analysis revealed that perception of government autonomy-support contributed positively to autonomous motivation and negatively to amotivation, while perception of government control was positively related to both controlled motivation and amotivation. As predicted, autonomous motivation was positively, and amotivation was negatively, associated with frequency of PEB.     

Effects of organic matter on phosphorus release kinetics in different trophic lake sediments and application of transition state theory

Sediments have a significant influence on the overlying water, and phosphorus (P) release from sediments is an important source for the lake eutrophication, particularly in shallow ones. In this study, effects of organic matter on P release from sediments in different trophic lakes from the middle and lower reaches of Yangtze River, China, were investigated, and the release kinetics of different P fractions at different temperature were studied. The results show that the release kinetics of soluble reactive phosphorus (SRP), dissolved organic phosphorus (DOP) and dissolved total phosphorus (DTP) were similar for the studied sediments, the release rate increased rapidly in the initial hours, and it increased gradually after 10h. The release kinetics of SRP, DOP and DTP followed the Power Function model. SRP was the major fraction among the released DTP, while DOP was an important fraction in the heavily polluted sediments. Organic matter restricted the SRP and DTP release while it promoted the DOP release. Both DOP and SRP release processes were endothermic. The thermodynamic properties in the P release kinetics were calculated and discussed.