PRB技术对PCBs及重金属污染地下水的试验研究

可渗透反应墙(Permeable Reactive Barrier PRB)技术是原位修复污染土壤及地下水的新型技术。试验以多氯联苯(PCBs)及重金属为靶污染物,设计3个PRB反应装置:柱Ⅰ、柱Ⅱ、柱Ⅲ,分别以还原铁粉、废料生铁、废料生铁与活性炭的混合物为反应介质,对PRB技术治理PCBs及重金属污染的地下水的可行性进行试验研究。试验结果表明:进入稳定期,柱Ⅰ、柱Ⅱ、柱Ⅲ对PCBs的去除效率分别为98%,97%,96%;对重金属(Cr、Cd、Pb、As)的去除效率均在97%以上。通过各柱处理,出水水质均达到地下水水质Ⅲ标准。说明PRB技术治理PCBs及重金属污染的土壤及地下水是可行的。     

中国海岛潮下带大型底栖动物时空分布特征

利用中国近海海洋综合调查与评价(908)专项生物调查数据,从海岛类型、地理分布等方面考虑,选取26个具代表性的中国海岛,对海岛潮下带大型底栖动物群落结构的时空分布特征进行分析研究.结果表明:26个海岛潮下带大型底栖动物共鉴定767种,各海岛底栖动物种类组成均以多毛类、软体动物和甲壳动物为主,棘皮动物所占比例较小;物种数在各海岛间差别较大,在空间分布上有较明显的北低南高特点;在季节分布上,海岛潮下带大型底栖动物物种数、栖息密度和Shannon-Wiener指数(H’)都表现出春季>夏季>冬季>秋季的特点,而生物量则表现出秋季>春季>夏季>冬季的特点;受人类活动影响较强烈的长三角地区海岛、近岸岛及河口岛潮下带大型底栖动物物种数及多样性指数明显低于其他海岛,说明目前中国海岛潮下带大型底栖动物群落结构已受人类活动的明显干扰.     

Return delays and evacuation order compliance: the case of Hurricane Georges and the Florida Keys

Abstract

Using interview data, we examine the effects of the heavily publicized delays in reentering the Florida Keys after Hurricane Georges on future evacuation intent. Of particular interest is the finding that the delays will have less influence on the future evacuation decisions of those who experienced them than on those who learned of them from secondary sources. Fear of return delays is only one factor in evacuation decision-making, albeit an understudied one. For this sample of evacuees, perceived risk is the most salient factor, and this risk assessment is not sufficiently diminished by the inconveniences, such as delays, associated with evacuation. For non-evacuees, however, the delay factor appeared to only increase their reluctance to evacuate the next time, despite their level of perceived risk.     

Guidance to improve the effectiveness of process safety management systems in operating facilities

The Process Safety Management (PSM) systems at the operating facilities in the Oil & Gas and in Chemical manufacturing industries have matured over the years and have become, at most facilities, very robust and sophisticated. These programs are administrated by Process Safety (PS) teams at both the corporate business units and plant levels and have been effective in reducing the number and severity of PS events across the industries over the past 25 years or so. Incidents however are occurring at a regular interval and in recent times several noteworthy PS events have occurred in the United States which have brought into question the effectiveness of the PSM programs at play. These facilities have been applying their PSM programs with the expectation that the number and severity of PS events would decrease over time. The expected result has not been realized, especially in context to those facilities that have undergone the recent incidents. Current paper reviews a few publicly available PS performance reports of Oil & Gas and Chemical manufacturing industries. The authors identified a few factors at play that have led to these PS events based on their experience, literature review, and incident investigation reports. Most of the factors are intertwined with multiple PSM elements and it requires a holistic approach to address them. Each of the factors is described and the path forward is proposed to improve the effectiveness of PSM programs.     

复合介质人工浮岛对缓流水体N、P修复研究

针对目前人工浮岛技术对氮磷去除效率低的现状,提出了一种层状复合介质人工浮岛原位水体净化技术,通过试验对其受水力停留时间、气水比及温度的影响进行了研究。试验结果表明,该人工浮岛技术对于缓流地表水体N、P去除效果较好,且优于传统人工浮岛装置。随着水力停留时间的增加,其去除率增大,通过试验进一步确定其适宜气水比为10:1,此时系统对氮磷的去除率比未曝气时增加1倍。在此运行条件下,水温高于13℃及水力停留时间为2.5d时,人工浮岛系统对水体中氨氮、硝酸盐氮、总氮和总磷的平均去除率分别为87.6%、63.8%、82%和83.5%;当水温低于13℃时去除率显著降低,此时延长HRT至7d时,系统对总氮和总磷仍有较高的净化效果,去除率分别为70.1%和69.2%。     

海岛环境管理的特殊性及其对策

随着海岛开发活动的不断加剧,海岛环境管理势在必行,但又困难重重,这是由其特殊性决定的.本文从海岛环境、海岛发展历程、海岛区位和海岛物权等几个方面分析了海岛环境管理的特殊性.在此基础上,通过对法律、行政、技术、经济和宣传等五种环境管理手段应用于海岛环境管理的具体分析,提出了海岛环境管理问题的基本对策.     

Effects of reduced water quality on coral reefs in and out of no‐take marine reserves

Near‐shore marine environments are increasingly subjected to reduced water quality, and their ability to withstand it is critical to their persistence. The potential role marine reserves may play in mitigating the effects of reduced water quality has received little attention. We investigated the spatial and temporal variability in live coral and macro‐algal cover and water quality during moderate and major flooding events of the Fitzroy River within the Keppel Bay region of the Great Barrier Reef Marine Park from 2007 to 2013. We used 7 years of remote sensing data on water quality and data from long‐term monitoring of coral reefs to quantify exposure of coral reefs to flood plumes. We used a distance linear model to partition the contribution of abiotic and biotic factors, including zoning, as drivers of the observed changes in coral and macro‐algae cover. Moderate flood plumes from 2007 to 2009 did not affect coral cover on reefs in the Keppel Islands, suggesting the reef has intrinsic resistance against short‐term exposure to reduced water quality. However, from 2009 to 2013, live coral cover declined by ～50% following several weeks of exposure to turbid, low salinity water from major flood plume events in 2011 and subsequent moderate events in 2012 and 2013. Although the flooding events in 2012 and 2013 were smaller than the flooding events between 2007 to 2009, the ability of the reefs to withstand these moderate floods was lost, as evidenced by a ～20% decline in coral cover between 2011 to 2013. Although zoning (no‐take reserve or fished) was identified a significant driver of coral cover, we recorded consistently lower coral cover on reserve reefs than on fished reefs throughout the study period and significantly lower cover in 2011. Our findings suggest that even reefs with an inherent resistance to reduced water quality are not able to withstand repeated disturbance events. The limitations of reserves in mitigating the effects of reduced water quality on near‐shore coral reefs underscores the importance of integrated management approaches that combine effective land‐based management with networks of no‐take reserves.     

Numerical simulations on the attenuation effect of a barrier material on a blast wave

This paper numerically modeled previous experimental results and quantitatively revealed the attenuation effect of a barrier material on a blast wave. Four fluids were considered in the present study: the detonation products, water, foamed polystyrene, and air. These fluids were modeled by Jones-Wilkins-Lee (JWL), stiffened gas, and ideal gas equations of state. A mixture of water and foamed polystyrene was used as a barrier to encircle a 0.1 kg mass of spherical pentolite, and the interface problem between the barrier and the blast wave was investigated. The simulation parameters were the radius and the water volume fraction of the barrier. To elucidate the effect of the barrier, we conducted two series of numerical simulations; one without a barrier, and another with a barrier of 50 or 100 mm in outer radius and 0–1 in the water volume fraction. Peak overpressure, positive impulse, and pressure history all agreed well with the previous experimental results. We focused on the energy transfer from high-pressure detonation products to other fluids. The sum of the kinetic energies of the detonation products and the barrier induced by the blast wave could quantitatively estimate the attenuation effect of the blast wave and was minimized when the water volume fraction was 0.5, as was the case in the previous experiment.     

噪声控制材料的性能测试

阻塞、吸收、制止或隔离噪声达到噪声控制的目的。噪声障碍材料的降噪效果与材料的性能有关。本文提供一些常用降噪材料的阻塞和吸音的技术性能     

Importance of Assessing Population Genetic Structure before Eradication of Invasive Species: Examples from Insular Norway Rat Populations

Abstract:  Determining the inter-island migration abilities of pest species and delimiting eradication units enable more viable long-term eradication campaigns because recurrent colonization from neighboring islands is avoided. We examined the genetic structure of the invasive Norway rat ( Rattus norvegicus ) to identify gene flow between islands and delimit population units at different geographical scales. We investigated variation in eight microsatellite loci in rat populations from 18 islands, representing five archipelagos off the Brittany coast (France). Although most of the islands are isolated from each other, short genetic distances, weak F_ST values between close islands, and a high level of cross-assignment showed that individuals collected on different islands could represent a single population unit. A Bayesian clustering method also supported the existence of high levels of gene flow between some neighboring islands. Thus, the statement "one island equals one population" can be false when inter-island distances are less than a few hundred meters. Genetic studies enable the definition of island clusters among which migration may occur that should be considered eradication units. To avoid reinvasion and to minimize ecological and economic costs, rats on all islands in an eradication unit should be eradicated simultaneously. We suggest that the genetic monitoring we performed here can be applied for management of any pest.