3B坝段坝身孔洞洞周应力应变分析

百色水利枢纽 3B坝段孔洞密集 ,且在空间位置上相互交错。为此 ,采用三维有限元数学模型对 3B坝段坝身孔、洞进行应力应变分析 ,定量分析了各工况下坝体孔、洞周边的应力应变量值及分布特征 ,评价了坝体应力的安全性 ,为孔、洞周边配筋提供了设计依据     

地下水埋深较大条件下农田深层渗漏模拟研究

为了能够在设计灌溉制度时充分考虑深层渗漏的影响,以辽宁大连地区地下水埋深比较大的农田玉米种植为例,采用VADOSE/W程序建立一维有限元模型,在对多年长系列气象资料进行分析的基础上,对枯水年、中水年和丰水年3种典型年在雨养、喷灌、畦灌条件下农田土壤水分的变化过程进行了长历时的模拟,并与实测值进行对比,以分析深层渗漏的产生规律。结果表明,在地下水埋深较大的情况下,深层渗漏占有效降雨与灌溉水量的比例,雨养条件下小于5%,喷灌条件下为5%~9%,畦灌条件下为7%~13%;70%~95%的深层渗漏由灌溉引起;13%~28%的有效灌溉水量会转化为深层渗漏。在设计灌溉制度时,深层渗漏的影响不容忽视。     

Effective distribution of domestic wastewater effluent between percolation trenches in on-site treatment systems.

On-site treatment systems discharging to groundwater rely on the effective distribution of effluent across a percolation area to provide an appropriate loading rate for the subsoil. In Ireland, this is achieved in a distribution box which splits the effluent evenly between the requisite number of percolation pipes. The flow regime experienced at four different distribution boxes was monitored continuously over twelve month periods which established that the most common flow rates at the distribution unit were in the range 1-4 litres/minute for a four to five person dwelling. In addition, the average flow rate from the four sites was only 100 litres per person per day, compared to recommended design value of 180 litres per person per day. Two distribution boxes were also tested in the laboratory to assess their distribution efficiency over a range of loading rates. The most commonly installed unit was found to significantly favour two out of the four trenches and both units were shown to perform particularly poorly at a range of different off-level installation angles. Modifications to the boxes were also tested, involving plastic V-notch inserts which were shown to greatly improve the hydraulic distribution and make the unit much less sensitive to off-level installation or subsidence.     

Biodegradation of bisphenol A and 4-alkylphenols by Novosphingobium sp. strain TYA-1 and its potential for treatment of polluted water

We investigated the use of Novosphingobium sp. strain TYA-1 for the simultaneous removal of bisphenol A (BPA) and 4-alkylphenols (4-APs) from complex polluted waters. Strain TYA-1 degraded BPA and utilized it as a sole carbon and energy source via oxidative skeletal rearrangement involving the cytochrome p450 monooxygenase system. Strain TYA-1 also degraded 4-APs with branched side alkyl chains (4-tert-butylphenol [4-tert-BP], 4-sec-butylphenol, 4-tert-pentylphenol, 4-tert-octylphenol [4-tert-OP], and branched nonylphenol mixture) via 4-alkylcatechols but could not degrade 4-APs with linear side alkyl chains. Degradation of 4-APs, like that of BPA, involved the cytochrome p450 monooxygenase system in strain TYA-1. A sequencing batch bioreactor (100 mL of polluted water [50 mg/L BPA, 50 mg/L 4-tert-BP, and 5 mg/L 4-tert-OP]; 6 h of reaction time/cycle; 12 cycles in total) containing alginate-immobilized TYA-1 cells (15 mg dry cells) simultaneously removed BPA, 4-tert-BP, and 4-tert-OP from complex polluted waters. These immobilized TYA-1 cells could be reused for a total of 9 cycles without any loss of degradation activity. Our results support the potential of using immobilized TYA-1 cells for the simultaneous removal of BPA and 4-APs from complex polluted waters.     

E. coli transport in soil columns: implications for reuse of treated wastewater in irrigation.

Reuse of treated wastewater in irrigation is gaining recognition as a vital element in the water resources management plan of developing countries, especially those situated in arid and semi-arid regions. An understanding of the transport of residual pollutants from treated wastewater, such as bacteria, in soil as a result of irrigation is critical to assessing health risks and the possible contamination of limited groundwater resources. In this work, retention of E. coli is evaluated for a soil that is irrigated by treated wastewater for growth of non-food crops near Egypt's Red Sea coast. In particular, the effects of soil organic fraction (SOF) and hydraulic loading rate (HLR) were investigated in laboratory soil columns. The matrix of experiments included three HLRs and three SOFs. The retention of bacteria by adsorption was observed at HLRs of 5 and 13 cm/h, with the magnitude of the adsorption increasing proportionally to the SOF. The impact of SOF was greater for the lower HLR. At the lowest HLR investigated (5 cm/h), filtration was also observed for the two higher SOFs (0.674 and 2.04 per cent). At a high HLR (66 cm/h) simulating flood irrigation, retention of bacteria was minimal regardless of the SOF. Since the bacterial solution is applied to a dry soil column to simulate field conditions, E. coli breakthrough after two pore volumes of throughput (vs. one) provided a meaningful comparison of bacterial retention as a function of HLR and SOF.     

P3软件在龙滩水电站右岸导流洞洞身施工中的应用

龙滩水电站右岸导流洞洞身段长849．421m，合同工期为2002-06-18～2003-09-30，通过运用Primavera Project Planner(以下简称P3)软件对导流洞洞身施工进度进行控制，在施工中不断调整施工进度，针对新的施工进度制定施工方案，使导流洞施工进度安排得更加合理，导流洞工程能按照施工总进度计划进行施工，保证红水河按期截流．     

Isolation of Salmonella sp. in sludge from septage treatment plant.

Waste stabilization ponds (WSP) are an often-used option to treat faecal sludges collected from on-site sanitation systems. Since agricultural use is one of the most attractive options for sludge disposal, specific guidelines on the hygienic sludge quality must be fulfilled, such as for viable helminth eggs and Salmonella sp. Although Salmonella isolation methods are well known for other types of samples, they are not suitable for faecal sludge. The reason can be attributed to the co-existence of a native bacterial sludge flora masking Salmonella development, especially if this bacteria is present at low concentrations. In order to select the best methodology for Salmonella recovery from septage sludge, different culture media were assayed at different incubation periods and temperatures. The proposed methodology for Salmonella recovery from sludge can be summarised as follows: (1) enrichment in Rappaport-Vassiliadis broth at 43 degrees C, 48 hours, and (2) isolation in XLD agar at 40 degrees C, 24 hours. Identification of suspected colonies by biochemical tests: TSI, LIA, urease and serological confirmation with Group O Antigen.     

Dynamics of the nitrogen transformation in a shallow stream and possible interventions.

This paper presents the assessment of the efficiency of the main biological nitrogen transformation processes in a shallow well-oxygenated river and conditions under which they are active and stabilise. The process dynamics was studied with the help of mathematical modelling of 2 years on-line data series measured in a reach of the Toess River, Switzerland. The algal nitrogen uptake was very stable and unaffected by most but frequent flood events. Daylight photosynthetic nitrogen uptake stabilised at 6 mgN mstreambed(-2) h(-1) (15 degrees C), dark uptake on storage products at rates of 0.5-2.5 mgN mstreambed(-2) h(-1). Nitrogen uptake by heterotrophic bacteria in the hyporheic zone was relatively constant at a level of 1.5-3.5 mgN mstreambed(-2) h(-1). Streambed nitrification could establish only during periods with average an daily concentration of at least 0.3 g(NH4-N) m(-3) in river water for several weeks. The maximum nitrification rate was 35 mgN mstreambed(-2) h(-1) for 3 g(NH4-N) m(-3). The effects of reduced nitrification in the WWTP and of river banks shading on a sudden ammonium peak were simulated. A river reach endangered by ammonium spills should be kept open to sun to favour ammonium uptake by algae. In-stream nitrification reduces ammonium peaks efficiently but leads to toxic nitrite concentrations.     

规则波对大直径群桩作用的数值模拟研究

多桩柱结构在海洋工程中应用广泛,大直径群桩效应使得桩柱所受到的波浪力与单桩大为不同。首先使用基于势流理论开发的三维水动力分析程序DIFFRACT计算了单个圆柱和双圆柱所受到的波浪力,通过与相应解析解的对比验证了数值结果的准确性。进一步分析了大尺度多桩柱结构在规则波中所受的波浪力。群桩间的水动力相互作用使桩群中每个圆柱所受的波浪力存在多个峰值,其最大值可达单个圆柱所受波浪力的2.30倍,并且最大波浪力圆柱的位置受桩群布置的影响。     

The transformation of aluminium species in the processes of coagulation, sedimentation and filtration.

The aluminium toxicity is closely related to aluminium species. In this work aluminium was fractionated into seven forms: Al(T), Al(Sus), Al(C + S), Al(S), Al(C), Al(O) and Al(I). Four Al-based coagulants and simulated raw water were used in the laboratory to investigate the aluminium transformation in coagulation, sedimentation and filtration processes. It is the use of Al-based coagulants that contributes more to the increase of the residual aluminium for the low-turbidity raw water, while the Al-based coagulants, especially the polymeric aluminium coagulants, work to remove the aluminium from the high-turbidity raw water. In the case of traditional coagulants, the increase of the turbidity or the dissolved organic carbon (DOC) concentration in the raw water results in a high concentration of Al(C + S). The removal rate of aluminium species in the filtration process is not only related to its size: RAl(Sus) > RAl(C+S), RAl(C) > RAl(S), but also to the physicochemical properties of aluminium species and filter. For the kaolin-polyaluminium chloride system, a lower removal rate of aluminium species results is due to the complexation of humic acid and aluminium species.     

泵站前池单排方柱整流措施数值模拟

为改善泵站前池内水流流态,基于Fluent软件,运用RNG k-ε模型对加单排方柱的正向进水泵站前池流态进行数值模拟,分析单排方柱的几何参数对前池流态改善的影响。结果表明:单排方柱具有分流效果,流经单排方柱的水流会向前池两侧分散,在单排方柱的后方形成漩涡。无整流措施时,泵站前池流态紊乱;通过在前池加设单排方柱可显著改善流态;单排方柱宜布置在前池前中部,不宜布置在两侧回流区内;方柱宽度越小,分流作用越小,行近流速分布越不均匀。     

Application of the Innovative Trend Analysis Method for the Trend Analysis of Rainfall Anomalies in Southern Italy

In this paper, an investigation of the temporal rainfall variability, in a large area of southern Italy, has been carried out using a homogeneous monthly rainfall dataset of 559 rain gauges with more than 50 years of observation. The area under investigation is a large portion of the Italian peninsula, ranging from the Campania and the Apulia regions in the North, to Sicily in the South, and covering an area of about 85,000 km². Possible trends in seasonal and annual rainfall values have been detected by means of a new graphical technique, ?en’s method, which allows the trend identification of the low, medium and high values of a series. Moreover, the Mann–Kendall test has been also applied. As a result, different values and tendencies of the highest and of the lowest rainfall data have emerged among the five regions considered in the analysis. In particular, at seasonal scale, a negative trend has been detected especially in winter and in autumn in the whole study area, whereas not well defined trend signals have been identified in summer and spring.     

自由面区域变换法解三体船兴波问题

为求解三体船兴波问题,基于线性自由面条件的势流兴波理论Rankine源方法,利用物理平面与计算平面的转换关系计算自由面上物理量的导数,开发了三体船兴波阻力预报程序.采用该方法和程序,对不同侧体布局的Wigley三体船兴波阻力及波形进行计算,并将计算结果与模型试验结果、其他作者数值计算结果进行比较,验证了该方法对三体船的适用性,表明采用贴水线网格及自由面区域变换法解三体船兴波问题可提高三体船兴波问题求解效率.     

Biosorption of Pb2+ and Cd2+ in a fixed bed column with immobilised Chorella sp. biomass

The biosorption of Pb2+ and Cd2+ in a fixed bed column by immobilised Chlorella sp. was characterised in a fixed bed column. Effect of initial concentration of Pb2+ and Cd2+, pH, and pellet size on the biosorption capacity was studied, at laboratory scale, using a factorial experiment design 2(3), in a 10 cm heightx1 cm of diameter continuous flow column packed with immobilised biomass. Equilibrium uptake of Pb2+ and Cd2+, increased with increasing initial metal ion concentration. It was favoured to pH 5, with a pellet of 5 mm of diameter. Langmuir model described the biosorption equilibrium of both metals.The biosorption of each single cation was studied too in a large column (50 cm heightx5 cm of diameter) at bench scale with a range of flow of 40 to 80 mL min(-1). The mass transfer coefficient was determined fitting the experimental data to continuity equations that were discretised in the radial terms with orthogonal collocation method.     

我国水电厂技术改造综述

自改革开放以来， 我国的水电建设取得了迅猛发展。至１９９８ 年底， 全国水电装机容量已达６６ ０６５ Ｍ Ｗ，年发电量达２ ０４３ 亿ｋ Ｗ·ｈ ， 分别占全国电力总装机容量的２３８ ％ 和年总发电量的１７６ ％ ； 已建成或已投产发电的１ ０００ Ｍ Ｗ 以上的大型水电厂有１４ 座。随着水电事业的不断发展， 水电在电力系统中的地位、作用和效益也日益突出， 并对水电厂的安全、可靠运行提出了更高的要求。为此， 对一批已建成投产的水电厂特别是 “六五”以前建成投产的老电厂， 必须进行全面的技术改造， 以不断挖掘设备潜力和增强电网的调峰能力。笔者以亲身经历， 就我国近年来特别是 “八五” 以来老水电厂进行技术改造所取得的成绩和经验给予了充分肯定， 指出了当前水电厂机电设备存在的主要问题， 提出了当前机电设备改造与技术进步的工作重点和目标， 并就全面加强水电厂的技术改造工作阐述了应遵循的原则。