地下水大尺度非列线不等距采样网的优化研究

采样的方法决定地质统计学中克立格法的估值精度。以研究区由开采井构成的具有99个地下水位长期观测孔的观测网为例,对地下水大尺度非列线不等距最佳采样网的合理性选择方法进行了研究。以采样点要避免过滤效应、分团效应以及采样数据分布要满足均匀性和随机性的检验准则为原则,选择了具有66个样本点的最佳采样网。     

Uncertainty propagation in FE modelling of a fire resistance test using fractional factorial design based model reduction and deterministic sampling

In this paper, fractional factorial design (FFD) and deterministic sampling (DS) are applied to a finite element (FE) model of a fire resistance test of a loaded steel beam, to investigate how uncertainties are propagated through the FE model. The sought quantity was the time when the deflection of the beam exceeded 225 mm. The FFD method was used as a model reduction technique which reduced the number of uncertain parameters from 5 to 3. The DS method was compared to a reference Monte Carlo (MC) method of 1000 simulations from all 5 uncertain parameters, which was the minimum number of simulations in order for the statistical moments to converge. The combined FFD and DS method successfully computed the propagation of the mean and standard deviation in the model, compared to the MC method. Given the uncertainties in the FE model, the fractional factorial design reduced the number of simulations required in the DS method by 82%. The combined method of FFD and DS reduced the number of required simulations by 96% compared to the MC method. The DS method did not capture the tails of the probability distribution and is therefore not a suitable candidate for probabilistic evaluation of the time of failure at the edges of the domain of possible failure times. Future research could very well be on improving the tails in DS. However, the DS method provides a conservative 95% coverage interval of 6 min for the time to failure of the steel beam.     

Status of the indoor air chemical pollution in Japanese houses based on the nationwide field survey from 2000 to 2005

This paper describes the present state and the changes in indoor air pollution levels by Volatile Organic Compounds (VOCs) in houses in Japan, as revealed through measurements of indoor VOC concentrations and investigations on the actual conditions in the residential environment by means of a questionnaire survey covering a total of more than 10,000 newly built houses over six years (from 2000 to 2005). The VOCs initially measured were formaldehyde, toluene, xylene, and ethylbenzene, followed by the subsequent inclusion of styrene and acetaldehyde.     

Application of exceedance probability based on wind kinetic energy to evaluate the pedestrian level wind in dense urban areas

In the present study, assessment of wind environment within the pedestrian level domains of highly populated areas is carried out. Three typical models of a dense urban area are considered and numerically simulated in order to examine the effects of the geometry of such models on wind flow characteristics within the pedestrian domain of a street canyon located within this area. The calculated flow fields are employed to estimate the exceedance probabilities within the study domain using a new approach: average wind kinetic energy. The study is applied to Tokyo, Japan; based on its mean wind velocity data. The results demonstrate that the exceedance probability analysis of the pedestrian wind environment could be a valuable tool for assessing urban areas. Also, the calculated probabilities demonstrate substantial dependence on both the geometry of building arrays and the wind conditions of the considered domain.     

Performance of the Chemcatcher passive sampler when used to monitor 10 polar and semi-polar pesticides in 16 Central European streams, and comparison with two other sampling methods

We investigated the performance of the Chemcatcher, an aquatic passive sampling device consisting of a sampler body and an Empore disk as receiving phase, when used to monitor acetochlor, alachlor, carbofuran, chlorfenvinphos, alpha-endosulfan, fenpropidin, linuron, oxadiazon, pirimicarb and tebuconazole in 16 Central European streams. The Chemcatcher, equipped with an SDB-XC Empore disk, detected seven of the aforementioned pesticides with a total of 54 detections. The time-weighted average (TWA) concentrations reached up to 1 microg/L for acetochlor and alachlor. Toxic units derived from these concentrations explained reasonably well the observed ecological effects of pesticide stress, measured with the SPEAR index. In a follow-up analysis, we compared the Chemcatcher performance with those of two other sampling systems. The results obtained with the Chemcatcher closely matched those of the event-driven water sampler. By contrast, the TWA concentrations were not significantly correlated with concentrations on suspended particles. We conclude that the Chemcatcher is suitable for the monitoring of polar organic toxicants and presents an alternative to conventional spot sampling in the monitoring of episodically occurring pollutants.     

Design and Calibration of a Simple Instrument for Measuring Dust on Surfaces in the Indoor Environment

Abstract A simple method for quantifying dust on indoor non-textile surfaces has been developed and evaluated. The method uses gelatine foils to sample particles from surfaces, applying a constant pressure. The foils possess unique properties, making them particularly suitable for evaluation by light extinction. The amount of particles collected as measured by laser light extinction is expressed as the area percentage covered by particles. Foil sampling effectiveness has been estimated to range from 87% to 97%. A simple method for calibrating the instrument has been developed. The relation between the total projected particle area excluding overlap can be determined from the measured projected area including overlap from a simple equation. An overall uncertainty is given, including effects of positioning foils in the detector, sampling from rough surfaces, and the natural variability due to the discrete nature of particles. The lower level of detection for dust on an object is less than 0.5% surface area covered by dust. The method has formed the basis for suggesting a sampling strategy and surface dust limits in relation to cleaning and the quality of the indoor environment.     

‘Between a rock and a hard place’: the failure to agree on regulation for the private rented sector in England

The private rented sector in England presents a number of widely-acknowledged problems for the policy maker including relatively poor property conditions and sometimes low management standards. There are a number of intractable obstacles to dealing with these problems, including an inability to agree on how the sector should be regulated, extreme variation in letting arrangements, a lack of clarity on the relationship between regulation and supply, industry distrust of regulation, and an anti-landlord culture.     

Remediation of PAHs in a saline-alkaline soil amended with wastewater sludge and the effect on dynamics of C and N

Contamination of soil with hydrocarbons occurs frequently and organic material, such as sludge, is often applied to accelerate their dissipation. Little is known, however, how sludge characteristics affect removal of polycyclic aromatic hydrocarbons (PAHs) from alkaline-saline soil. Soil of the former lake Texcoco with pH 9 and electrolytic conductivity 7 dS m(-1) was contaminated with phenanthrene and anthracene and amended with sludge, sterilized sludge, sludge adjusted to maintain pH in contaminated soil or glucose plus an inorganic N and P source while emission of CO2 and concentrations of NH4+, NO3-, NO2-, extractable P, phenanthrene and anthracene were monitored in an aerobic incubation experiment of 112 days. An agricultural soil from Acolman treated in the same way served as control. Contaminating the Texcoco soil increased emission of CO2 significantly, but not in the Acolman soil. After 112 days, the largest concentration of anthracene and phenanthrene was found in the Acolman soil added with glucose and the lowest in the sludge-amended soil. The largest concentration of anthracene in the Texcoco soil was found in soil added with sterile sludge and the lowest in the sludge-amended soil. The largest concentration of phenanthrene in the Texcoco soil was found in the glucose-amended soil and the lowest in the sludge-amended soil. It was found that addition of sludge removed more phenanthrene, but not anthracene from soil compared to the unamended contaminated soil, glucose inhibited dissipation of PAHs while microorganisms in the sludge contributed to their removal, and adjustment of soil pH had no effect. Organic material can be used to accelerate removal of hydrocarbons from soil, but the effect is controlled by soil type, contaminant and organic material characteristics.     

A study on the development and application of the E/V shaft cooling system to reduce stack effect in high-rise buildings

This study suggests the E/V(Elevator) shaft cooling system as a new approach to reduce the stack effect and the related problems in high-rise buildings. The basic characteristics on its application were analyzed with some simulations in this study. Moreover, the system was applied to an actual building and its performance was evaluated through the measurements.The system can reduce the stack effect itself and the related problems simultaneously and it can reduce the pressure and the air flow rate in each part of a building in the same ratio. These features were shown in the results of the simulations; for the examples, when all the E/V shafts were cooled from 22 °C to 12 °C, the stack effect and the pressure in each part of the modeled building were decreased by about 27%.In the field measurements, the wind velocity through the E/V door was decreased effectively in the whole building; its reduction ratio at the lobby floor was about 25% and at the upper floors (37F, 38F) about 10% respectively. But, the neutral pressure level at the E/V shaft was moved by the vertical temperature difference in the E/V shaft because of the inflow ducts concentrated in the lower part of the E/V shaft. This movement was also shown in another simulation on the same conditions as the measured ones. It is very important to minimize the vertical temperature difference in the E/V shaft to maximize the reduction effects on the problems.     

Using a battery of bioassays, benthic phytoplankton and the AUSRIVAS method to monitor long-term coal tar contaminated sediment in the Cache la Poudre River, Colorado

This survey provides information on sediment toxicity and structural characteristics of the macroinvertebrates and benthic phytoplankton at 10 locations in the Cache la Poudre River after long-term exposure to coal tar residue. The application of the Australian river bioassessment system (AUSRIVAS) as well as a biotest battery was used to evaluate the river ‘health’ condition. Coal tar is a dense nonaqueous-phase liquid of significant environmental concern due to its toxicity and persistence in the subsurface. Organisms like Selenastrum capricornutum, Daphnia magna and Chironomus tentans, representing different complexities in the biosphere, were selected as test systems for ecotoxicological studies. The results obtained in this study indicate that a biotest battery, macroinvertebrate and benthic phytoplankton communities are in principle suitable biological tools for evaluation of toxic oil and coal-derived substances in long-term contaminated river sediment.     

Effects of laying order and experimentally increased egg production on organic pollutants in eggs of a terrestrial songbird species, the great tit (Parus major)

In this study, concentrations and profiles of organic pollutants were investigated in a passerine species with a large clutch size, the great tit (Parus major). In the first clutches, mean egg concentrations decreased significantly in relation to the laying order from 3025 ± 416 ng/g lw to 2267 ± 386 ng/g lw for sum PCBs and from 989 ± 339 ng/g lw to 695 ± 320 ng/g lw for sum DDTs. Sum PBDE concentrations also decreased in relation to the laying order from 68 ± 10 ng/g lw to 53 ± 11 ng/g lw, but not significantly. Although laying order effects were found, variation in concentrations within clutches was smaller than among clutches. To further investigate the impact of laying large numbers of eggs on levels and profiles of organic pollutants, initiation of replacement clutches was experimentally induced. Mean sum PCB and sum PBDE concentrations were significantly lower in eggs of replacement clutches compared to first clutches. In addition, first clutches had a higher contribution of the higher chlorinated and more persistent PCB congeners, CB 170, 180 and 183, and a lower contribution of CB 52, 95 and 149 compared to replacement clutches. Because of the differences in concentrations and profiles between the first and replacement clutches, the combined use of eggs from both the first and replacement clutches for monitoring purposes is not recommended. In conclusion, we suggest that, due to the larger variation among clutches compared to the variation within clutches, one randomly collected great tit egg from a first clutch is useful as a biomonitoring tool for organic pollutants. To our knowledge, this is the first study in which the impact of an experimentally increased clutch size on the levels and profiles of contaminants in eggs has been investigated.     

Evaluation of a chemical munition dumpsite in the Baltic Sea based on geophysical and chemical investigations

This paper discusses the results of geophysical and chemical investigations carried out in a chemical munition dumpsite in the southern Baltic Sea, east of the island of Bornholm. After WW2 over 32,000 tons of chemical war material was dumped here including shells and bombs as well as small drums and containers. The geophysical investigations combined very-high-resolution seismics and gradiometric measurements. The results indicate the presence of a large number of objects buried just below the seafloor. The size of the objects and their distribution, with a marked increase in density towards the center of the dumpsite, suggests that we are dealing with dumped war material. Sediment and near-bottom water samples, taken within the dumpsite and in the surrounding area, were analysed for the presence of various chemical warfare agents (CWA) including Adamsite, Clark, sulphur mustard, tabun, chlorobenzene and arsine oil. The results indicate a widespread contamination that reaches far beyond the dumpsite boundary. CWA degradation products were found in most of the sediment samples. The contamination was mostly related to arsenic containing compounds; only one sample indicated the presence of sulfur mustard. Although the correlation between detected objects and CWA concentrations is not always straightforward, the overall results suggest that a lot of the dumped war material is leaking and that over the years the contamination has reached the seafloor sediments.     

The application of heat pipe heat exchangers to improve the air quality and reduce the energy consumption of the air conditioning system in a hospital ward—A full year model simulation

Research was conducted to study the effect of heat pipe heat exchangers on the existing air conditioning system of a hospital ward located in Malaysia, a tropical region. The present research employs the transient system simulation software (TRNSYS) to study the hour-by-hour performance of the system in terms of supply duct air and indoor air conditions in the ward space. Fieldwork study showed that the existing air conditioning system operating in the Orthopaedic Ward, University of Malaya, Malaysia is not capable of providing the desired supply duct air and indoor air to the space. Therefore, the possibility of improving the air conditioning system by adding heat pipe heat exchangers was investigated. The impact on energy consumption, power savings, supply duct air and indoor air with heat pipe heat exchangers incorporated in the air conditioning system were simulated and the results were compared with the existing system.Based on the present research, the system with the added eight-row heat pipe heat exchangers is recommended to provide convenient and healthy air into the ward space according to the ASHRAE recommendations. Moreover, it was found that by applying the new design, a considerable amount of energy and power could be saved.     

实施水泥和混凝土夏令标准养护制度的节能措施研究

以浙江省为例,进行了南方缺电省份夏令水泥和混凝土绿色节能养护制度的探讨.实施夏令标准养护制度,将混凝土养护温度和水泥试验室温度均由20℃提高28℃,这样做既能节电节能,又接近实际工程,接近含混合材料与掺合料泵送混凝土的夏季实际水化硬化过程.我国的南方,疆域辽阔,若所有试验室都采用这一节电节能措施,将具有巨大的经济效益和社会效益.     

关注城市整体塑造特色环境--唐山市总体城市设计实践回顾

介绍了总体城市设计概念和理论提出的背景，结合唐山市总体城市设计实践案例，对总体城市设计实践进行了总结和回顾。     

The structural variability of quarters and residential areas in the historical texture of the city of Yazd based on Islamic rules and jurisprudence: a case study of Golchinan quarter

According to many researchers and scholars, religious beliefs can be considered as the most influential factor in forming Muslim urban spaces and their architectural elements. In fact, historical cities reflect the culture and beliefs of their residences. Among all historical places in Iranian cities, the historical texture of the city of Yazd, especially the quarters since the age of Qajar dynasty, are well preserved. The present study aims at identifying the Islamic principles and values influencing the formation of architectural spaces and the extent of their applications in one of the historical quarters known as Golchinan. The results of the conformation of the theoretical findings with the data acquired from field studies revealed that almost 90% of the urban and architectural spaces (e.g. residential areas, mosques, bazaars, and pathways) in Yazd are directly influenced by Islamic principles. In other words, there is a strong conformity between the accepted Islamic values of the society and what actually was applied to urban constructions during Qajar dynasty.     

The comparison of two heavy fuel oils in composition and weathering pattern, based on IR, GC-FID and GC-MS analyses: Application to the Prestige wreackage

This paper compares the weathering patterns of two similar fuel oils: a fuel oil spilled after a ship accident (Prestige-Nassau, off the Galician coast -NW Spain-) and a fuel designed to cope with the numerous quests for samples to carry out scientific studies (IFO). Comparative studies were made to evaluate the capability of common fingerprinting analytical techniques to differentiate the fuels, as well as their capabilities to monitor their weathering. The two products were spilled under controlled conditions during ca. four months to assess how they evolved on time. Mid-IR spectrometry and gas chromatography (flame ionization and mass spectrometry detectors) were used. IR indexes related to total aromaticity, type of substituents (branched or linear chains) and degree of aromatic substitution reflected well the differences between the fuels during weathering. Regarding the chromatographic measurements, the n-alkanes became highly reduced for both fuel oils and it was found that the PAHs of the synthetic fuel (IFO) were more resistant to weathering. Regarding biomarkers, the different profiles of the steranes, diasteranes and triaromatic steroids allowed for a simple differentiation amongst the two products. The %D2/P2 ratio differentiated both products whereas the %N3/P2 one ordered the samples according to the extent of their weathering.     

Complexation of copper in the effluent of a sewage treatment plant and an estimate of its influence on toxicity to coho salmon

Measurements by cupric ion electrode of the complexing capacity of the effluent from a sewage treatment plant (STPE) averaged 0.300 mg 1⁻¹. Of the complexed Cu 67% was due to compounds of 10,000 MW. Organic compounds removable by activated carbon composed 88% of the total organic carbon and were responsible for 87% of the complexation. Complexation of Cu²⁺ by STPE diminishes the toxicity from total Cu to juvenile coho salmon; the LC₅₀ was 0.164 mg 1⁻¹ for river water vs 0.286 mg 1⁻¹ for 40% STPE. The LC₅₀ of Cu²⁺ was approximately the same (0.017 vs 0.022 mg 1⁻¹) in both matrices; this species thus appears to play a toxic role. The mean survival time in diluted STPE with added Cu was inversely proportional to the Cu²⁺ concentration.     

主成分分析法识别岩溶多重介质含水系统水化学和水动力特性——以贵州后寨岩溶典型小流域为例

基于主成分分析,以贵州后寨典型岩溶含水系统为例,对该区1995年8月到1996年8月的10个代表性站点的20个变量进行分析,结果表明,前两个主成分综合携带了全部信息的89．3％。从变量的主成分判别平面图上得出第一主成分F1主要由Ca^2＋、SIc（方解石饱和指数）、SId（白云石饱和指数）、HCO3^-、总硬度、Mg^2＋决定,第二主成分F2主要由K^＋＋Na^＋、Cl^-、SO4^2-、HCO3^-,SO4^2-、TOD、水温等决定;水流流经地层的岩性是后寨流域内岩溶含水系统水化学类型和各种水化学参数在空间和时间上变化的主要控制因素,次要因素是地下水的水动力条件特别是地下水的径流深度。水文地球化学信息对地下水系统的水动力特征分析具有指示意义,而主成分分析法耦合水动力和水化学方面的信息,为深入了解岩溶含水系统水动力化学特征提供了一种途径。     

Escalation of commitment in troubled IT projects: Influence of project risk factors and self-efficacy on the perception of risk and the commitment to a failing project

Past studies have indicated that project managers may be less likely to continue failing IT projects if they are able to perceive project risks accurately. Using the scenario of a failing IT project, a computer simulation-based experiment investigated the influence of individual self-efficacy and project risk factors on the perception of risk. Participants played the role of a project manager and managed a simulated IT project. The results suggest that project managers are likely to underestimate the risks of a project with endogenous risk factors as compared to a project with exogenous risk factors. Results of this study point to a ‘self-efficacy bias’ where project managers with higher self-efficacy may underestimate the risks of a troubled IT project as compared to project managers with lower self-efficacy. Further, risk perception mediated the influence of self-efficacy on the commitment to a failing IT project.