Shear wave velocity and geotechnical properties of tailings deposits

Bulletin of Engineering Geology and the Environment - This paper presents the results of subsurface shear wave velocity Vs measurement of tailings deposits (tailings sand and slime) at 4 tailings...     

中国城市分区规划研究的回顾与展望

作者从中国城市分区规划的由来与发展过程入手，分析了分区规划目前面临的问题，并对分区规划研究的发展作出了初步展望。     

资源型小城镇发展规划与设计——以山西泽州县下村镇为例

一、资源型小城镇总体特征区位特征:就交通区位而言,一般位于区域交通干线上,是片区交通枢纽和物资集散中心;就经济地理位置而言,     

建筑桩基设计中若干问题的探讨

本文对目前建筑桩基设计中的下述问题提出探讨 :a)关于人工挖孔灌注桩与机械成孔灌注桩实际承载能力的比较 ;b)关于桩长与桩端持力层的选择 ;c)关于岩层桩端承载力的确定方法 ;这些问题的解决 ,有利于正确评价桩基的承载能力 ,有利于桩基础设计的优化     

上海世纪公园国际花卉区彩色沥青路面设计与施工

通过科研及上海世纪公园国际花卉区彩色沥青路面的应用 ,阐述其原材料性能及配合比设计、施工等要点 ,证明其性能达到同类产品的技术指标且价格适中 ,在市政建设中将具有广阔前景。     

城市人居环境建设中环境友好理念的引入

我国城市人居环境建设面临着人地关系紧张、城市生态环境的恶化、城市交通运输梗塞、城市文化消失等问题.应将环境友好理念引入城市人居环境规划、建设和管理中,并以此为基础,制定具体的工作内容和方法.     

建设部鼓励推广应用实用技术

前段时间,香港报纸刊载了几例工程技术应用实例,引起中央有关领导和建设部领导的重视。经有关专家分析论证,建设部相关部门决定今后采取相应措施和适当方法,鼓励内地有关单位和相关工程推广使用此类技术和产品。     

Diurnal variation of dissolved gaseous mercury (DGM) levels in a southern reservoir lake (Tennessee, USA) in relation to solar radiation

Variations of dissolved gaseous mercury (DGM) concentrations in a southern reservoir lake (Cane Creek Lake, Cookeville, TN, USA) in relation to solar radiation were investigated consecutively from June 2003 to May 2004. The daytime DGM levels in the lake exhibited a two-phase diurnal trend; the DGM concentrations rose in the morning, peaked around noontime and then fell in the afternoon through the evening; these trends followed the general pattern of diurnal solar radiation variations. The morning and afternoon phases appeared to be asymmetrical with the former relatively steep and the latter gradual. A variety of daytime DGM level variations other than the typical two-phase diurnal patterns were also observed. For the time spans studied, the daytime mean DGM concentrations of the lake ranged from 12 to 68 pg L(-1) (60-340 fM). The daytime mean DGM levels in the summertime (June, July, August) showed values above 30 pg L(-1) (150 fM) in most cases and a large number of peak DGM concentrations above 50 pg L(-1) (250 fM). The summer DGM levels in the lake appear to be comparable to those observed in the large northern lakes for the summertime. The daytime DGM levels in the lake were found to correlate with solar radiation to various degrees (cases of r values above 0.8: approximately 12% and approximately 18% of the total sampling days for correlation with global solar radiation and UVA radiation, respectively). Correlating trends are recognizable between the daytime mean DGM concentration and the corresponding mean global solar radiation (r = 0.66, p < 0.0005) and between the daytime mean DGM concentration and the corresponding mean UVA radiation (r = 0.62, p < 0.0005).     

Study on two operating conditions of a full-scale oxidation ditch for optimization of energy consumption and effluent quality by using CFD model

The operating condition of an oxidation ditch (OD) has significant impact on energy consumption and effluent quality of wastewater treatment plants (WWTPs). An experimentally validated numerical tool, based on computational fluid dynamics (CFD) model, was proposed to optimize the operating condition by considering two important factors: flow field and dissolved oxygen (DO) concentration profiles. The model is capable of predicting flow pattern and oxygen mass transfer characteristics in ODs equipped with surface aerators and submerged impellers. Performance demonstration and comparison of two operating conditions (existing and improved) were carried out in two full-scale Carrousel ODs at the Ping Dingshan WWTP in Henan, China. A moving wall model and a fan model were designed to simulate surface aerators and submerged impellers, respectively. Oxygen mass transfer in the ditch was predicted by using a unit analysis method. In aeration zones, the mass inlets representing the surface aerators were set as one source of DO. In the whole straight channel, the oxygen consumption was modeled by using modified BOD-DO model. The following results were obtained: (1) the CFD model characterized flow pattern and DO concentration profiles in the full-scale OD. The predicted flow field values were within 1.98 ± 4.28% difference from the actual measured values while the predicted DO concentration values were within −4.71 ± 4.15% of the measured ones, (2) a surface aerator should be relocated to around 15 m from the curve bend entrance to reduce energy loss caused by fierce collisions at the wall of the curve bend, and (3) DO concentration gradients in the OD under the improved operating condition were more favorable for occurrence of simultaneous nitrification and denitrification (SND).