2012年国内外石油化工行业事故统计分析

按照事故级别、所属板块、事故类型、事故时间、涉及的化学品、发生国家,对2011年和2012年国内外石油化工行业发生的死亡1人以上的事故进行了统计分析,研究了事故动态和趋势.结果表明:重特大事故呈上升态势,具有“小概率、大后果”的特点;事故涉及的化学品种类很集中;我国伤亡事故金字塔呈现出“底部小、形状陡”的特点;死亡人数/起数比值与经济发展水平有关;爆炸事故的起数和死亡人数最高,事故起数增幅较大,火灾事故起数增幅不大,但死亡人数有大幅度增加,泄漏事故和其他事故的起数、死亡人数均有所降低.根据统计分析的结果,从加强未遂事件管理、引进OSHA绩效考核机制、加强危险品运输和化工企业安全监管、加大安全投入和提升安全技术装备水平等方面提出了建议措施.对研究国内外石化行业的事故动向,从整体上防范事故发生,具有重要的指导意义.     

Optimum Heat Conductance Distribution for Power Optimization of a Regenerated Closed Brayton Cycle

In this paper, the power output of the cycle is taken as objective for performance optimization of an irreversible regenerated closed Brayton cycle coupled to constant-temperature thermal energy reservoirs in the viewpoint of finite time thermodynamics (FTT) or entropy generation minimization (EGM). The analytical formulae about the relations between power output and pressure ratio are derived with the heat resistance losses in the hot- and cold-side heat exchangers and the regenerator, the irreversible compression and expansion losses in the compressor and turbine, and the pressure drop loss in the piping. The maximum power output optimization is performed by searching the optimum heat conductance distribution corresponding to the optimum power output among the hot- and cold-side heat exchangers and the regenerator for the fixed total heat exchanger inventory. The influence of some design parameters, including the temperature ratio of the heat reservoirs, the total heat exchanger inventory, the efficiencies of the compressor and the turbine, and the pressure recovery coefficient, on the optimum heat conductance distribution and the maximum power output are provided. The power plant design with optimization leads to smaller size including the compressor, turbine, and the hot- and cold-side heat exchangers and the regenerator.     

Climate Change in Southern and Eastern Africa During the Past Millennium and its Implications for Societal Development

Climatic records from equatorial eastern Africa and subtropical southern Africa have shown that both temperature and the amount of rainfall have varied over the past millennium. Moreover, the rainfall pattern in these regions varied inversely over long periods of time. Droughts started abruptly, were of multi-decadal to multi-centennial length and the changes in the hydrological budget were of large amplitude. Changing water resources in semi-arid regions clearly must have regional influences on both ecological and socio-economic processes. Through a detailed analysis of the historical and paleoclimatic evidence from southern and eastern Africa covering the past millennium it is shown that, depending on the vulnerability of a society, climatic variability can have an immense impact on societies, sometimes positive and sometimes disastrous. Therefore, the interconnected issue of world ecosystem and social resilience is the challenge for decision-makers if sustainable development is to be reached on global and local levels.     

EVALUATING RELIABILITY OF STORAGE SCHEMES WITH DENDROHYDROLOGY AND THE HURST PHENOMENON1

ABSTRACT: The mean annual flow at a damsite during a water project yield study of several decades may differ considerably from the mean flow of several hundred years. The frequency of the most severe droughts of record may be much different than apparent from the historical record as well. Dendrohydrology and the Hurst Phenomenon provide means to evaluate the validity of the study period for project reliability analysis. The most severe hydrologic drought (1928–1934) affecting the watersheds of the Sacramento River and tributaries in Northern California during the 75-year period 1906–1980 was also the worst drought in 421 years (1560–1980). In contrast, the most severe drought (1945–1951) in the Santa Ynez River watershed in Santa Barbara County, California, during the 62-year period 1918–1979 was the ninth worst drought in 443 years (1537–1979). Thus, in one case the drought risk indicated by the dendrohydrologic time series would actually be less; in the other, actual risk would be greater than perceived from the historical record. In the absence of a dendrohydrologic prehistoric time series, Hurst Phenomena would have provided clues to this outcome. Hurstian plotting of the accumulated deviation from the mean for long time series facilitates observation of the wet-dry regime of the examples and identification of characteristics that should be accounted for in water development planning.     

Disaster in the South Paciic: Impact of tropical cyclone "Nomu" on the Solomon Islands, May 1986

Tropical Cyclone "Namu" struck the Pacific nation of the Solomon Islands during 18-20th May 1986. It was sthe most serious natural disaster in the Solomons in lining memory. Nearly a third of the total population of 267,000 were diriven from their homes and 150 people were killed, with damage estimates beginning in AUD 25 million. It has been estimated by the Solomon Islands Ministry of Economic Planning that it will take seven years for the economy to recover. This paper discusses the major events of the disaster episode by employing the Powell and Rayner model of "disaster-time." Factors relating to current disaster Planning and management within the Solomon Islands are outlined. The paper also highlights assistance provided by Australla during the Post-impact sequence and illustrates the type of general disaster preparatory support which Australia provides to South pacific.     

Recursive residuals and model diagnostics for normal and non-normal state space models

Model diagnostics for normal and non-normal state space models are based on recursive residuals which are defined from the one-step ahead predictive distribution. Routine calculation of these residuals is discussed in detail. Various diagnostic tools are suggested to check, for example, for wrong observation distributions and for autocorrelation. The paper also discusses such topics as model diagnostics for discrete time series and model discrimination via Bayes factors. The case studies cover environmental applications such as analysing a time series of the number of daily rainfall occurrences and a time series of daily sulfur dioxide emissions.     

DISCHARGE AND SUSPENDED SEDIMENT PATTERNS OF AN INTERMITTENT COLD DESERT STREAM1

Sage Creek in south‐central Wyoming is listed as impaired by the U.S. Environmental Protection Agency (USEPA) due to its sediment contribution to the North Platte River. Despite the magnitude of sediment impacts on streams, little research has been conducted to characterize patterns of sediment transport or to model suspended sediment concentration in many arid western U.S. streams. This study examined the relationship between stream discharge and suspended sediment concentration near the Sage Creek and North Platte River confluence from 1998 through 2003. The objectives were to determine patterns of stream discharge and suspended sediment concentration, produce a sediment prediction model, and compare sediment concentrations for the six‐year period. Stream discharge and suspended sediment transport responded rapidly to convective storms and spring runoff events. During the study period, events exceeding 0.23 m³/s accounted for 92 percent of the sediment load, which is believed to originate from erodible headwater uplands. Further analysis of these data indicates that time series modeling is superior to simple linear regression in predicting sediment concentration. Significant increases in suspended sediment concentration occurred in all years except 2003. This analysis suggests that a six‐year monitoring record was insufficient to factor out impacts from climate, geology, and historical sediment storage.     

Fracture Characterization Using Borehole Radar: Numerical Modeling

Forward modeling of borehole radar data for a series of synthetic discrete-fracture network (DFN) models provides a conceptual framework for interpreting experimental field data at fractured rock sites. A finite-difference time-domain (FDTD) radar wave propagation model was developed for this purpose. Synthetic examples demonstrate the utility of single-hole reflection-mode and cross-hole transmission-mode borehole radar for (1) identification of fracture location and orientation, and (2) identification of fracture pore-fluid properties, which might change as a result of tracer tests or flooding exercises in support of resource development or site remediation. A two-dimensional, synthetic DFN was generated statistically based on hypothetical distributions of fracture length, orientation, aperture, permeability, and inter-connectivity. The DFN includes a zone of permeable fractures embedded within a network of lower-permeability fractures and a low-permeability rock matrix. We modeled the unconnected and non-permeable fractures as being filled with freshwater. To simulate tracer experiments, contaminant releases, or engineered-remediation processes, we considered alternately the inter-connected, permeable fractures to be filled with freshwater air, or saline water (tracer). Synthetic radar data sets for both single-hole reflection and cross-hole transmission modes were generated. The features in synthetic radargrams were then examined and compared to the DFN model to evaluate the likelihood of identifying fracture location, orientation, and pore fluid in field situations. This comparison demonstrates that (1) the replacement of freshwater with saline water in permeable fractures generally increases the amplitude of reflections from permeable, connected fractures; and (2) in general, radar reflection-mode data contains more information about fracture properties than transmission-mode data.     

实时荧光定量PCR技术对氨氧化细菌的研究

传统的PCR技术只能实现对核酸的定性检测而无法对其进行定量研究。随着分子生物学技术的发展,在传统PCR技术的基础上发展起来的实时荧光定量PCR技术实现了对核酸的定量研究。该技术是向常规PCR反应体系中加入荧光染料或荧光探针,通过监测PCR反应过程中荧光信号的变化来实现对核酸的定量。实时荧光定量PCR技术具有应用范围广、灵敏度高、操作简单、工作量低等特点,在医学和微生物学领域已广泛地应用于疾病诊断、病毒定量检测、微生物群落结构分析及演替规律的研究。文章综述了该项技术的原理、特点及其在环境氨氧化细菌研究中的应用,同时也指出了该技术存在的问题及其发展应用前景。     

Effects of operational factors on soluble microbial products in a carrier anaerobic baffled reactor treating dilute wastewater

The effects of feed strength,hydraulic residence time(HRT),and operational temperatures on soluble microbial product(SMP) production were investigated,to gain insights into the production mechanism.A carrier anaerobic batfled reactor (CABR) treating dilute wastewater was operated under a wide range of operational conditions,namely,feed strengths of 300-600 mg/L,HRTs of 9-18 h,and temperatures of 10-28℃.Generally, SMP production increased with increasing feed strength and decreasing temperature.At high temperature (28℃),SMP production increased with decreasing HRT. As the temperature Was decreased to 18 and 10℃.the SMP production was at its peak for 12 h HRT Therefore,temperature could be an important determinant of SMP production along with HRT. A higher SMP to soluble chemical oxygen demand (SCOD) ratio Was found at high temperature and long HRT because of complete volatile fatty acid degradation.SMP accounted for 50%-75% of the SCOD in the last chamber of the CABR.As a secondary metabolite.some SMP could be consumed at lower feed strength.