城郊排水沟渠溶质传输的暂态存储影响及参数灵敏性

选择Na Cl为示踪剂,于2013年9~10月在合肥城郊的关镇河支渠开展5次瞬时投加示踪实验.从暂态存储、侧向补给和对流-扩散等作用机制层面,设置4种模拟情景,解析暂态存储作用对于排水沟渠溶质传输规律的影响,并对OTIS模型参数进行灵敏性分析.结果表明,暂态存储对于主流区Cl-模拟浓度穿透曲线(BTCs)峰值大小影响很大,相对偏差高达24.23%~117.26%,显著高于对峰值出现时间的影响,且暂态存储影响显著超过了侧向补给作用;由相关性分析,主流区Cl-模拟浓度BTCs峰值大小和出现时间的相对偏差与As/A具有极显著相关性;4个主要参数的灵敏度排序为AAsαD.     

Catastrophic Reproductive Failure, Terrestrial Survival, and Persistence of the Marbled Salamander

Abstract:  Wide variation in reproductive success is common among amphibians that breed in seasonal ponds, but persistence of adults can buffer against these fluctuations, particularly for long-lived species. We hypothesized that the frequent episodes of catastrophic failure of the marbled salamander ( Ambystoma opacum ) enhance the importance of high terrestrial survival. At Rainbow Bay in South Carolina reproductive success was poor (<1 metamorph/breeding female) in nearly half of the 22 years that the species bred. Complete failure occurred in 6 of 22 years. To study catastrophic failure, we adapted an age-structured, individual-based model with density-dependent growth and survival of larvae. The model was based on extensive data from local field studies and experiments. With consistently good survival in the pond stages, the simulated population required survival probabilities in the upland stages (juveniles and adults) near 0.5/year to persist and near 0.8/year to achieve the increases observed. Catastrophic failure, occurring randomly with probability 0.5/year, created additional fluctuations in the population, raised the thresholds of survival required for persistence, and caused extinction under conditions that were otherwise favorable. The marbled salamander at Rainbow Bay is not at great risk of extinction because of catastrophic failure, but the risk increases dramatically if life span is decreased or frequency of failure is increased. Any reduction in terrestrial survival will have deleterious consequences by reducing the breeding populations at equilibrium, even if it does not jeopardize persistence. Our model provides assessments of risk that can be applied to poorly studied species with similar life histories, such as the endangered flatwoods salamander ( A. cingulatum ).     

聚糖菌颗粒污泥基于胞内储存物质的同步硝化反硝化

采用特殊运行方式的厌氧-好氧SBR系统(厌氧后排水),以乙酸钠为有机基质成功富集了聚糖菌颗粒污泥.聚糖菌颗粒污泥厌氧-好氧批式实验表明,聚糖菌颗粒污泥具有较强的SND能力,TOC/N分别为5.0,4.0,2.8时,SND效率分别96.4%、95.3%及96.2%,而周期总氮去除效率随着碳氮比降低而降低,分别为66.0%、61.2%及56.3%.通过对周期氨氮、亚硝酸盐氮、硝酸盐氮、TOC以及胞内糖原、PHB变化的测定分析,证明聚糖菌颗粒污泥SND过程中,污泥以厌氧阶段储存于胞内的多聚物PHB作为反硝化碳源,并且反硝化聚糖菌是系统中反硝化能力的来源.与溶解性基质相比,PHB的降解速率相对较低,因此在SND过程中,反硝化可以与硝化保持相近的速率,从而有助于获得良好的SND效果.     

I-Risk: development of an integrated technical and management risk methodology for chemical installations

This paper presents an integrated quantitative risk assessment method for hazardous installations, taking into account management as well as technical design and producing risk level measures. The key components of the I-Risk methodology are the technical model, the management model and their interface. The technical model consists of developing a master logic diagram (MLD) delineating the major immediate causes of loss of containment (LOC) and associated quantitative models for assessing their frequency. The management model consists of the tasks, which must be carried out systematically in the primary business functions (such as operations, emergency operations, maintenance and modifications). A management audit quantifies the quality of these management tasks. The management–technical interface modifies certain parameters of the technical model on the basis of the quality of the safety management system of the specific installation. The methodology is exemplified through its application to the risk assessment of an ammonia storage facility. A detailed technical model simulating the response of the system to various initiating events is developed along with a detailed management model simulating the influence of the plant-specific management and organisational practices. The overall effect is quantified through the frequency of release of ammonia as a result of a loss of containment in a storage tank and in a pipeline.     

油库泵站可燃气体智能型安全检测系统

根据目前油库泵站内存在可燃气体经常泄漏的实际情况,提出并应用计算机信息处理系统解决可燃气体泄漏监控问题。     

蒙德法在火电厂液氨储罐评价单元的应用

火电厂液氨储罐单元存在大量高纯度的液氨,一旦发生火灾、爆炸,后果极其严重。为了研究液氨储罐的火灾爆炸危险性及毒性,在对火电厂液氨储罐危险性辨识的基础上,依据液氨储罐单元的主要参数,运用蒙德法分别确定评价中需要的各种危险性系数,从而进行各项指标计算,查询危险性等级表,将各项指标进行等级划分,结论表明各项危险等级都很高。在得出结论基础上,进行安全措施补偿评价,补偿后的各种危险等级均降低,可见采取补偿措施后能够一定程度的降低火灾、爆炸、毒性的危险性,防止事故的发生。     

液化天然气储罐9％镍钢焊缝相控阵AUT工艺

9％镍钢液化天然气储罐制造安装过程中,焊缝检验通常用常规射线照相（RT）进行。本文研讨用相控阵半自动超声检测（AUT）取代射线照相的工艺制定及验证方法。要领分四步：首先带缺陷专用焊接试样的制备;然后相控阵AUT工艺的编制;其次在有已知缺陷的焊接试样上,对AUTT艺作“开放性”验证试验;最后在现场对整个数据采集系统作“封闭性”操作演示和验证评定试验。验证结果表明相控阵AUT取代RT可行可靠,能凸显AUT种种优势。     

Ignition temperatures of dust layers and bulk storages in hot environments

In many industrial installations, particulate solids (cereals, agri-food products, coal, plants, etc.) are stored or processed. Self-heating of these products, which can lead to fires and explosions, can occur in a variety of situations. Examples include large storage at room temperature, formation of a layer on a hot surface, layer deposited on a surface – insulating or conductive – in a hot environment or even storage of product exposed to heating on one side.The main parameters that determine the occurrence of self-heating are the size of the container, the temperature, the residence time and the characteristics of the product. Depending on the type of situation encountered and these implementation conditions, the analysis of self-heating risks must be based on specific models and/or parameters.This paper presents the different variants and combinations of the theoretical model from the theory of thermal runaway to represent self-heating, taking into account in particular the symmetry or asymmetry of heating, reagent consumption and boundary conditions. It also discusses their adaptation to the previous identified industrial situations.Nine products were chosen to be representative of those used in the different considered industrial situations. They were subjected to self-heating basket tests in isothermal ovens in order to determine the parameters for applying the described theoretical models. These results were compared with the results of self-heating tests in layers of different thicknesses in a hot environment, on an insulating or conductive plate, using a specially developed test protocol, as well as with the results of standardized tests of minimum ignition temperature in 5 mm layers.This led to the proposal of the most appropriate theoretical model to represent the self-heating phenomenon for each of the four identified industrial situations.This analysis can promote better design of industrial equipment and production conditions (temperatures, volumes or product flows …) in order to prevent fires and explosions.     

粉煤灰资源的农业利用

本文根据粉煤灰农业利用的基础及国内外研究现状，阐述了粉煤灰农业利用现状，包括直接施用于农田、利用粉煤灰生产化肥、贮灰场覆土或不覆土造田和填坑造地等。并对粉煤灰农业利用的前景提出了一些看法。     

Predatory behavior and chemical communication in two Metapone species (Hymenoptera:Formicidae)

Summary. Colonies of two species of Metapone (M. madagascarica, M. new species.) were collected in Madagascar and established in laboratory nests. It could be demonstrated that both species are specialist predators of termites (Cryptotermes kirbyi). During hunting the ants sting the termites and thereby paralyze and preserve the prey alive. In this way prey can be stored in the ant nest for extended periods. During foraging and colony emigrations the ants lay chemical trails with poison gland secretions. Among the seven compounds identified in the venom only methyl pyrrole-2-carboxylate elicits trail following behavior in both Metapone species. Received 11 February 2002, accepted 23 February 2002.