基坑支护组合钢支撑设计与施工技术

通过镇江市邮电通信指挥中心大楼深基坑工程的设计与施工,全面介绍了组合钢支撑在深基坑支护工程应用中的设计、施工方法及支撑效果.实践证明,组合钢支撑是一种施工方法简单、施工速度快、对周边环境影响小、安全可靠的支撑形式,具有较强的市场竞争能力及良好的推广应用前景.     

A mass balance approach to estimate the dilution and removal of the pollutants in stream water polluted by acid mine drainage

 A few simple mass balance equations were developed to simultaneously estimate how much the pollutants from acid mine drainage (AMD) in stream water are diluted and removed during their migration. The application of the equations requires knowledge of the variations in the concentrations of the dissolved pollutants and the stoichiometry of the precipitation reaction of the pollutants when none of the pollutant shows a conservative behavior along the stream path. The calculation should be restricted to the pollutants showing much higher concentrations in the polluted main stream water than in the combining or diluting water of the same target area. The mass balance equations were applied to estimate the dilution factor and precipitation fractions of pollutants in Imgok Creek such as Fe, SO₄ and Al from the AMD of Yeongdong mine. The results show that the estimation, especially for SO₄ and Al, significantly depends on the kinds of the precipitates. When FeOHSO₄ and AlOHSO₄ are assumed to precipitate, the maximum removal fractions of SO₄ and Al by precipitation are respectively 34% and 46% of the original input, which is much higher than the values estimated when SO₄ is considered to be perfectly conservative. It indicates that the stoichiometry of precipitation reaction is very important in the interpretation of the pollutant dilution and migration and assessment of environmental impacts of AMD. The applicability of the mass balance equations may still need to be verified. However, examining the calculated dilution factor and precipitation fractions with the equations can provide invaluable information on not only the behavior but also unexpected input of the pollutants in the stream water polluted by AMD and other point sources. Received: 12 November 1997 · Accepted: 30 March 1998     

浮床无土栽培植物控制池塘富营养化水质

采用浮床无土栽培技术,在池塘水面种植景观植物--陆生植物美人蕉(Cana generalis     

Using δN values in algal tissue to map locations and potential sources of anthropogenic nutrient inputs on the island of Maui, Hawai‘i, USA

Macroalgal blooms of Hypnea musciformis and Ulvafasciata in coastal waters of Maui only occur in areas of substantial anthropogenic nutrient input, sources of which include wastewater effluent via injection wells, leaking cesspools and agricultural fertilizers. Algal δ¹⁵N signatures were used to map anthropogenic nitrogen through coastal surveys (island-wide and fine-scale) and algal deployments along nearshore and offshore gradients. Algal δ¹⁵N values of 9.8‰ and 2.0-3.5‰ in Waiehu and across the north-central coast, respectively, suggest that cesspool and agricultural nitrogen reached the respective adjacent coastlines. Effluent was detected in areas proximal to the Wastewater Reclamation Facilities (WWRF) operating Class V injection wells in Lahaina, Kihei and Kahului through elevated algal δ¹⁵N values (17.8-50.1‰). From 1997 to 2008, the three WWRFs injected an estimated total volume of 193 million cubic meters (51 billion gallons) of effluent with a nitrogen mass of 1.74 million kilograms (3.84 million pounds).     

Assessment of Urban Source Metal Levels in Influent,Effluent, and Sludge of Two Municipal Biological Nutrient Removal Wastewater Treatment Plants of Bursa,an Industrial City in Turkey

Removal of Al, As, Cd, total Cr (Tot. Cr), Cu, Total Fe (Tot. Fe), Mn, Ni, Pb, Sb, Sn, and Zn from urban effluent by wastewater treatment plants (WWTPs) operated under five‐stage Bardenpho® process were investigated and water soluble metals in the dewatered sludge were quantified. Samples were collected from two WWTPs on a weekly basis over an approximately 2.5‐year time span. Tot. Fe and Al were the most abundant, As, Pb, Ni, Cu, and Cd were the least abundant metals in the influents of both WWTPs. Removal efficiencies above 75% were achieved for Tot. Cr, Tot. Fe, Al, and Cu, whereas, no significant removal was observed for As, Cd, Pb, Sb, and Sn. Removal of Tot. Cr, Cu, Tot. Fe, Zn, Al, Mn, and Ni were influenced by influent suspended solids concentrations, and of Tot. Cr, Zn, and Cd were influenced by their initial content in the influent. Zn removal efficiency of biological nutrient removal (BNR) system in this study was higher and Cd removal efficiency was lower than that of conventional activated sludge reported in the literature. No remarkable difference for metals such as Cu, Mn, Ni, and Pb was observed between the removal efficiencies of conventional system and BNR system.     

Cercis siliquastrum Tree Leaves as an Efficient Adsorbent for Removal of Ag(I): Response Surface Optimization and Characterization of Biosorption

The Cercis siliquastrum tree leaves are introduced as a low cost biosorbent for removal of Ag(I) from aqueous solution in a batch system. FT‐IR, XRD analysis, and potentiometric titration illustrate that the adsorption took place and the acidic functional group (carboxyl) of the sorbent was involved in the biosorption process. In addition, it was observed that the pH beyond pH_pzc 4.4 is favorable for the removal procedure. The effect of operating variables such as initial pH, temperature, initial metal ion concentration, and sorbent mass on the Ag(I) biosorption was analyzed using response surface methodology (RSM). The proposed quadratic model resulting from the central composite design approach (CCD) fitted very well to the experimental data. The optimum condition obtained with RSM was an initial concentration of Ag(I) of 85 mg L^?1, pH = 6.3 and sorbent mass 0.19 g. The applicability of different kinetic and isotherm models for current biosorption process was evaluated. The isotherm, kinetic, and thermodynamic studies showed the details of sorbate‐sorbent behavior. The competitive effect of alkaline and alkaline earth metal ions during the loading of Ag(I) was also considered.     

不同黏土对中肋骨条藻的絮凝去除研究

比较了不同种类黏土对中肋骨条藻的絮凝去除效率, 分析了黏土理化特征对絮凝去除效率的影响。结果表明, 不同种类黏土的Zeta 电位为？36.1～？15.9 mV, BET 比表面积为0.31～60.76 m2/g, 硅铝比为1.35～3.62。当黏土用量均为0.50 g/L 时, 不同黏土对中肋骨条藻的絮凝去除速度和去除...     

资源一号卫星影像预处理方法研究

资源一号卫星的零级数据存在纵向规则条纹、横向不规则条纹、灰度不均衡、第四波段模糊等缺陷。本文探讨对资源一号卫星数据这些问题的预处理方法, 并提出资源一号卫星数据预处理软件系统的设计和实现的具体流程。     

如皋观测场搬迁前后气温对比分析

针对如皋观测场搬迁后气温偏低的现象,本文对产生这种现象的原因从环境条件、天气过程、土壤土质做了专题分析,结果表明:这种现象是多种因素共同作用的结果,其中最主要的是:(1)观测场环境变化是形成气温偏低的重要原因.(2)观测场所在地的土壤母质等地质背景是形成气温差异的条件之一.(3)冷空气的直接影响为气温差异提供了有利的背景.经分析揭示出:如皋观测场搬迁后的气温偏低现象是更自然地反映了大气自然状况.     

Biofiltration of Hexane Vapor: Experimental and Neural Model Analysis

Biofiltration is a commonly practiced biological technique to remove volatile compounds from waste gas streams. From an industrial view‐point, biofilter (BF) operation should be flexible to handle temperatures and inlet load (IL) variations. A compost BF was operated at different temperatures (30–45°C) and at various inlet loading rates (ILR; 8–598 g m^?3 h^?1) under intermittent loading conditions. Complete removal of n‐hexane was observed at 30 and 35°C at ILRs up to 330 g m^?3 h^?1. Besides, 20–75% of the pollutant was removed at 40°C, corresponding to the different ILs applied to the BF. Increasing the temperature to 45°C decreased the removal efficiency (RE) significantly. A feed forward neural network was used to predict the RE of BF with temperature and ILR as the input variables. The experimental data was divided into training (2/3) and test datasets (1/3). The best structure of neural network was obtained by trial and error on the basis of the least differences between predicted and experimental values, as ascertained from their coefficient of regression (R²) values. The modeling results showed that a multilayer network with the topology 2?10?1 was able to predict BF performance effectively with R²‐value of 0.995 for the test data. The results from this study showed the predicting capability of ANNs which can be considered as an alternative for conventional knowledge‐based models.