Biomagnification of organochlorine pollutants in farmed and wild gilthead sea bream (Sparus aurata) and stable isotope characterization of the trophic chains

Organochlorine pollutants (pesticides and polychlorinated biphenyls) were analysed in farmed and wild gilthead sea bream (Sparus aurata) tissues (white muscle and liver) from the Western Mediterranean (Spain) and in their diets. Determination was carried out by gas chromatography coupled to tandem mass spectrometry after clean up of the fatty extracts by normal phase HPLC, with detection limits around 0.1 ng/g. Carbon and nitrogen stable isotope ratios were also determined in the samples. Organochlorine compounds concentration was found to be uniform throughout the year in farmed fish, in both white muscle and liver. In contrast, wild fish showed contamination profiles that reflect environmental factors and the biological cycle. Although biomagnification factors for white muscle and liver were found to be 2.4 and 3.0, respectively for farmed fish, and 0.15 and 0.54 for wild specimens, wild fish presented higher levels of organochlorine contaminants than farmed fish. Nitrogen stable isotopes determination in muscle from wild and farmed sea bream during the year gave us a profile related to the biological cycle. delta(15)N mean values from farmed fish were 2.0 per thousand higher than from wild fish throughout the year that corresponding to close to one trophic step. delta(13)C values were stable during the year, and also more enriched in the case of farmed fish. The low levels of contaminants found in the feed supplied to farmed fish explain the organochlorine concentrations in their tissues which remain below wild fish, in spite of the intensive culture conditions and higher trophic level of cultured specimens.     

极端条件下尾矿库排洪系统失效溃坝影响规律研究

为了有效减少尾矿库溃坝对周围各类设施带来的不良作用,采用MIKE 21平面二维水动力模块模拟最终堆积标高时达到漫顶情况下出现溃口且溃口逐渐扩大导致失稳对周围1 km各类设施的影响规律,溃口形状为倒梯形,溃口位置选取对下游最不利位置（尾矿库东北坝）,生成二维溃坝演进模型,分别得到溃坝范围内的流量过程、淹没高程、淹没范围等数据。研究表明：该尾矿库在正常标高且良好管理下运行时,不会发生溃坝;当水库达到最高洪水位、排洪系统全部失效、遭遇远超1000年一遇洪水、24 h入库洪水总量超出安全运行水位至坝顶之间库容时,可能产生漫顶溃坝风险;洪水漫顶溃坝和边坡局部失稳溃坝后下泄的尾矿砂对东北侧砂场的影响均大于东南侧;洪水漫顶溃坝影响范围未超过1 km;局部边坡失稳溃坝下东北侧的溃坝影响范围超过1 km,但此时溃坝已停止,泥石流不再向前移动,风险处于可控状态。     

极端条件下地铁应急通信保障的思考与对策

针对地铁发生重特大灾害事故造成公网瘫痪、电力中断等极端条件下,消防救援队伍应急通信保障存在的不足,提出了地铁应急通信保障的对策建议。探讨了现阶段运用有线+无线自组网基站混合组网,未来修订完善标准规范,在隧道内利用“光纤直放站+天线”的方式搭建隧道无线信号覆盖平台、建设专用区间电话等系统的方式,制定了解决方案,并模拟“断路断电断网”等极端条件,多次组织在不同城市的地铁站进行实地测试和全流程、全要素演练,验证了该解决方案的可行性。     

极端天气条件下山火防控策略分析——以川渝地区山火为例

摘 要：川渝地区位于我国西南部,地处四川盆地及巫山东部,植被以亚热带常绿阔叶林为主,引发山火原因较多。受极端高温干旱天气影响,川渝地区山火的数量和强度持续增加,给当地造成了严重的生态灾难和社会危机。在概括近期川渝地区山火案例的基础上,从氧气、可燃物和引火源3方面分析引发该地山火的主要原因,并从地形、气候和植被方面分析扑救难点,从多角度出发提出相应山火防控策略。     

Energy simulation in the variable refrigerant flow air-conditioning system under cooling conditions

As a high-efficiency air-conditioning scheme, the variable refrigerant flow (VRF) air-conditioning system is finding its way in office buildings. However, there is no well-known energy simulation software available so far which can be used for the energy analysis of VRF. Based on the generic dynamic building energy simulation environment, EnergyPlus, a new VRF module is developed and the energy usage of the VRF system is investigated. This paper compares the energy consumption of the VRF system with that of two conventional air-conditioning systems, namely, variable air volume (VAV) system as well as fan-coil plus fresh air (FPFA) system. A generic office building is used to accommodate the different types of heating, ventilating, and air-conditioning (HVAC) systems. The work focuses on the energy consumption of the VRF system in the office buildings and helps the designer's evaluation and decision-making on the HVAC systems in the early stages of building design. Simulation results show that the energy-saving potentials of the VRF system are expected to achieve 22.2% and 11.7%, compared with the VAV system and the FPFA system, respectively. Energy-usage breakdown for the end-users in various systems is also presented.     

部分负荷工况下多台冷水机组的冷量分配

以两台相同冷量冷水机组并联运行的空调系统为例分析了部分负荷工况下机组的性能,指出如果不对机组的冷水出水温度进行重设,系统冷量只能是平均分配,而无法实现主从控制.     

Properties of thermal insulation materials during extreme environment changes

In this experimental study properties of condense formation, drainage and moisture dependent heat transmittance were studied for three different thermal insulation materials often used in railway carriages; glass wool (from Isover), melamine foam (Basotect) and corrugated sheets of cellulose plastics (Moniflex). The materials are quite different with respect to condense formation and maximal moisture accumulation at similar environmental conditions. They showed also considerable differences in moistures’ influence on thermal transmissivity. The higher the moisture accumulation, the bigger the moistures’ influence on thermal transmissivity at steady state. At a sudden reversion of the temperature field the moisture gave a temporary effect of even higher heat transmission for 1–2 h.     

极端气候条件下的罗沙旅舍设计分析

对瑞士罗沙旅舍的形体策略、空间领域性及其采用的生态技术进行了分析，并对罗沙旅舍的可持续理念与形式生成之间的关联性进行了探讨，通过太阳能的利用、节能减排等技术措施的实施，实现了可持续发展的设计目标。     

极端恶劣天气下如何提高公路应急保障能力

结合实例介绍了极端恶劣天气对社会经济的重大影响及危害,总结归纳了公路部门在暴雪冰冻极端天气条件下提高保障能力方面存在的问题,针对性地提出了提高抢险队伍应急作战保障能力的对策,具有一定指导意义。     

Performance-driven design methodology for habitation shell design in extreme conditions on Mars

The research project illustrates how performance-driven design tools can be conducted as an architectural design methodology that suggests an innovative approach to design a habitation shell in extreme environmental conditions without human assistance. This research study attempts to use environmental data revealed by NASA and its habitat design requirements to develop a conceptual design for an innovative habitation form and then simulate it with Mars conditions to analyze the habitation shell's structural behavior according to finite element analysis. In this regard, research phases, including layout configuration, form-finding, and structural analysis, have been conducted to explore a habitation concept implemented with generative design tools as a decision-maker in extreme conditions. In conclusion, two generated typologies of proposed habitation forms will be compared in terms of their structural performance under extreme loads of the martian environment. Within this research project, due to the numerous extreme challenges of design and construction of habitation in extreme conditions using conventional approaches, a performance-driven design methodology will provide a rational and sustainable design methodology to tackle extreme barriers to Mars's environment.     

Performance-driven design methodology for habitation shell design in extreme conditions on Mars

The research project illustrates how performance-driven design tools can be con-ducted as an architectural design methodology that suggests an innovative approa...     

Sensitivity analysis of jacket-type offshore platforms under extreme waves

Jacket-type offshore platforms play an important role in oil and gas industries in shallow and intermediate water depths such as Persian Gulf region. Such important structures need accurate considerations in analysis, design and assessment procedures. In this paper, nonlinear response of jacket-type platforms against extreme waves is examined utilizing sensitivity analyses. Results of this paper can reduce the number of random variables and consequently the computational effort in reliability analysis of jacket platforms, noticeably. Effects of foundation modeling have been neglected in majority of researches on the response of jacket platforms against wave loads. As nonlinear response of the pile foundation is one of the most important sources of potential nonlinearity in the response of offshore platforms, in this study, a powerful model which is able to consider Pile–Soil–Structure Interaction (PSSI) is employed. Therefore, PSSI parameters as well as other parameters such as uncertainties in the prediction of the wave force on jacket structure and uncertainties in structural model are utilized in sensitivity analyses. In this research, pushover methods as well as an advanced approach named “Incremental Wave Analysis (IWA)” are employed. Consequently, collapse prevention limit state of jacket platforms is investigated through different outcomes of pushover and IWA methods including Reserve Strength Ratio, ultimate capacity, collapse displacement and Collapse Wave Height indicators. In order to consider the effects of correlation between random variables, a robust method of sensitivity analysis named correlation coefficient approach is also employed.     

Cadmium and zinc interactions and their transfer in soil-crop system under actual field conditions

The transfer of Cd and Zn from calcareous soils nearby a non-ferrous mining and smelting bases to the spring wheat (Triticum aestivum L.) and corn (Zea mays L.) tissues and the interactions between the two metals concerned were investigated under actual field conditions. Samples of soils and entire crops were randomly collected during harvest time in 1998 in the Baiyin region. The soil metal contents showed that the furrows had been polluted (mean values: 3.16 mg kg(-1) for Cd; 146.78 mg kg(-1) for Zn) and the significant spatial variation of the soil contamination existed here (ranges, Cd: 0.14-19.3 mg kg(-1); Zn: 43.5-565.0 mg kg(-1)). The translocation ratios of the two metals from soil to crop parts in the region studied were relatively lower and the order of the element transfer in different plant tissues was root > stem > grain. The transfer ratio of element Cd was lower than that of element Zn. Cd and Zn uptake by the crop structures could be best described by four models (P < 0.01): linear; exponential; quadratic; and cubic. Apart from a linear relationship between the element Cd in the corn grains and soils, models were generally non-lincar. An analysis of Cd-Zn interaction mechanism led to the conclusion that the effects of the two metals were synergistic to each other under field conditions, in which increasing Cd and Zn contents in soils could increase the accumulations of Zn or Cd in the two crops.     

Phosphate uptake under anoxic conditions and fixed-film nitrification in nutrient removal activated sludge system

Simultaneous enhanced biological phosphate uptake and biological denitrification under anoxic conditions were investigated in a modified lab-scale nutrient removal activated sludge system. The aim of the experiments was to find whether poly-P bacteria are capable of taking up phosphate under anoxic conditions by utilising nitrate as an electron acceptor. The phosphate uptake in anoxic conditions was compared to that in aerobic environment in batch tests. The results of the long-term operation of continuous-flow lab-scale system as well as the results of batch tests showed that the anoxic phosphate uptake with simultaneous denitrification after preceding anaerobic substrate uptake could significantly reduce the extent of competition for organic substrate between poly-P bacteria and denitrifiers. A side-stream nitrification in fixed-film reactor enabled to reduce the losses of organic carbon by aerobic oxidation and to stabilise the slow-growing population of nitrifiers in the system.     

Modeling of semi-rigid beam-to-column steel joints under extreme loading

Joints play an important role in providing ductility for steel-composite structures subject to extreme loading conditions, such as blast, fire and impact. Due to sound energy dissipation capability and fabrication efficiency, semi-rigid joints have increasingly received attention during the last decade. This paper presents a component approach for modeling semi-rigid beam-to-column joints based on Eurocode3, where the post-elastic response, including component strain hardening and ultimate rotational capacity, is also considered. Failure criteria are defined based on the ultimate deformation capacity of components and bolt-rows. The model enables a direct integration of joint response into global frame models with the consideration of axial deformability, such that the interaction between bending moment and axial force within the joints can be realistically captured. In addition, elevated temperature can be considered in the joint model via the degradation of the component response. Through comparisons with available test data, the joint model is shown to have good accuracy, and the failure criteria are found to be reliable yet conservative. The strain hardening response of components is shown to have significant influence on the ultimate bending capacity of the joints, while neglecting it usually leads to a conservative prediction.     

相同外保温系统在不同气候条件下的节能率比较

采用与瓦克化学品有限公司“外墙外保温系统在多种气候条件下的应用”项目相同的对比房,用特征温度法模拟计算了采用相同外保温系统的建筑全年空调和采暖负荷。研究表明,对于完全相同的对比建筑,其全年的采暖与空调负荷及节能量在不同城市的差异可达10～20倍,说明气象条件是决定负荷和节能量大小的外在因素,相同外保温措施在不同气象条件下的经济价值和节能潜力有可能完全不同,这是建筑节能的个性;但对于相同建筑采取相同的外保温措施,在不同城市的全年采暖和空调节能率相近(约44%),这是建筑节能的共性规律。以重庆和哈尔滨的空调节能率为例,揭示了逐时、逐月空调负荷降低率与全年空调节能率的内在联系。     

复杂环境条件下深基坑设计方案的优化

邻近环境敏感设施的基坑围护结构设计多采取增加围护墙嵌固深度、增加坑内地基加固、基坑外设置隔断墙等措施对周边环境予以保护，造成的工程费用增加、工期延长等问题存在优化的可能。目前基坑工程的设计优化主要集中于围护墙的类型及构件的优化，缺少对整个基坑围护体系整体方案的优化研究。以与运营中的地铁车站及大直径雨水管相邻的建筑地下室基坑及地铁连通道基坑设计为例，以确保地铁车站及周边环境安全为目标，对基坑围护体系的设计方案进行了比选优化，分析采用三维有限元方法模拟实际开挖工况，并根据土体在不同阶段的受力特点，在初始应力状态分析及开挖过程模拟阶段对土体赋予不同的弹性模量。结果表明：对原设计方案进行了取消临时封堵墙，地下一层区与地下二层区同步施工的优化设计后，基坑周边建、构筑物安全，获得了安全、经济的方案。     

Resilience analysis of shield tunnel lining under extreme surcharge: Characterization and field application

A resilient system should have the ability to mitigate the disruption caused by unfavorable environment and to rapidly recover to an acceptable performance level. In this paper, a detailed model to assess resilience of shield tunnel is presented. The performance robustness under disruption and the subsequent recovery rapidity are emphasized in this model. The tunnel horizontal convergence is selected as the performance indicator. The resilience index (Re) is defined by the ratio of the integral of the performance transition function over the integral of the normal performance function. The rationality and applicability of the model is validated by a real case of extreme surcharge on Shanghai metro tunnel. In this case, the performance transition and the normal performance degradation are characterized by the measured data. 70–80% of the normal performance is disrupted due to the surcharge, but only 1% is recovered by unloading of the surcharge in 9 days and 12.4% is recovered after 4 years by the soil grouting in 38 days. It results in a resilience index (Re) between 0.28 and 0.45. The lesson learned from the case indicates that the high vulnerability of lining convergence due to the severe surcharge and the long time duration between recovery measures could result in weak resilient abilities for shield tunnels. The value of resilience index Re could be significantly increased by 73% on average if the recovery duration were shortened.     

超早期火灾探测报警系统的应用分析

介绍了高灵敏度空气采样感烟火灾探测系统的性能、结构特点及工作原理，并重点讨论了此系统在通信建筑环境中的具体应用。