低洼小区雨水排水的探讨

随着城市建设的大规模开展,大型低洼小区排水成为经常遇到的难题。该文通过工程实例,分析如何利用挡水设施、地面径流控制措施、现场外径流控制措施等方法,解决大型低洼小区雨水排水问题,以期用最低的投资来获取最大的排水安全性。     

软岩冻融损伤的水-热-力耦合研究初探

冻融力学研究正温、负温环境交替变化对材料的物理力学性质的影响。由于软岩为强度低、孔隙度大、胶结程度差、含有大量膨胀性粘土矿物的松散、软弱岩层。因此,软岩的水-热-力耦合不是一个简单的过程。初步提出了软岩的水-热迁移机理,进而提出了软岩水-热-力耦合的基本数学模型。最后用ANSYS软件模拟了隧道围岩温度场与应力场,得到了隧道围岩冻胀力的分布趋势。     

北京欢乐谷聚能飞船圆环柱动力基础设计研究

游乐设施设备基础作为一种特种结构,在我国建筑行业相关标准中还没有给出其相应的规范和条文。在《游艺机与游乐设施安全》(GB8408—2000)中也没有明确设备基础的设计方法与安全储备。结合欢乐谷工程的混凝土圆环柱设计,针对上述问题开展研究与探讨,通过优化结构形式和合理选取安全储备系数,采用近似计算与有限元分析相结合的方法进行设计,较好地解决了上述问题,并对圆环柱在弯、剪、扭作用下的结构计算进行了探讨。     

数据机房热环境影响因素研究

对某数据机房进行测量,以实测数据作为模拟的边界条件,采用开箱模型对机房热环境进行数值模拟,将模拟值与实测值进行对比,验证了模型的可靠性。在此基础上,分别对不同架空地板高度,送风孔板孔隙率,冷通道宽度以及不同挡板间距和高度等工况进行模拟,分析了各种因素对数据机房热环境的影响,得到了各个参数的最佳值,为数据机房的安全运行与节能优化提供指导。     

走近辽都——巴林左旗林东镇

掀开历史的画卷,辽都故地巴林左旗是一片神奇的土地。它位于内蒙古自治区赤峰市北部大兴安岭南段山麓南端,总面积6458.86平方公里。全旗共辖6个镇、10个乡、3个苏木,156个村委员会,547年自然村,总人口36万人口。旗政府所在地林东旗距赤峰市区272公里。全境属温带大陆性季风气候区。全旗土地总面积968.8290万亩,现有耕地147万亩,林地面积305万亩,森林覆盖率达30.7%。凭借丰富的林木资源,推动木材加工业的发展壮大,使之成为农牧民增收的重要渠道。全旗现有草牧场面积484万亩,为畜牧业的发展提供了充足的饲草资源,年产优质绵羊毛230吨、山羊绒1…     

Rheological and fractal characteristics of granular sludge in an upflow anaerobic reactor

The rheological and fractal characteristics of the granular sludge in an upflow anaerobic sludge blanket (UASB) reactor were investigated in this study. The influences of sludge concentration and temperature on the rheological properties of the granular sludge were evaluated, and the Bingham model was adopted to describe its rheology. In addition, image analysis was used to determine the sludge fractal dimension. The results indicate that the UASB granular sludge showed a shear-thinning behavior. The relationships between the limiting viscosity and the sludge concentration, as well as the limiting viscosity and temperature could be respectively modeled using an exponential equation and Arrhenius equation well. The Bingham model was able to adequately describe the rheology of the granular sludge. The fractal dimension of the granular sludge, 2.79+/-0.03, was larger than that of some other aggregates, suggesting that the granular sludge were more compact and denser. Furthermore, the relationship between rheological and fractal properties of the granular sludge could be properly described with the model proposed by Shih et al. [1990. Scaling behavior of the elastic properties of colloidal. Phys. Rev. A 42, 4772-4779].     

少数民族地区特色旅游规划及设施建设研究--以江华瑶族自治县旅游发展规划研究为例

在现代化建设日新月异的今天，针对少数民族地区做好旅游发展规划，如何加强营造城市特色，突出特质景观，保护其丰富而有内涵的人文自然环境，以风貌特色吸引游人，促进地方旅游和经济发展。     

浅议建筑工程招投标的策略与技巧

介绍了我国建筑工程招投标的策略与技巧，从投标策略、报价技巧、编标策略与技巧等方面进行了论述，指出熟练掌握投标技巧是提高企业中标率的关键。     

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).     

解读宜城民工潮

宜城市是湖北省首批小康市,位于江汉平原与南(阳)襄(樊)盆地的过渡地带,市域面积2115平方公里,耕地面积60万亩,市域人口54万,其中农村人口36万。近几年来,随着人增地减、农业生产率的提高,有限的土地和农村劳动力富余的矛盾越来越突出,加之乡镇企业二次创业、“五小”关闭,乡镇企业吸纳农民就业的能力锐减,全市农村富余劳力由1998年的