盘点城市

近些年,河南城乡建设取得长足进步,给我们留下太多的惊喜和惊奇。花园多了,建筑高了,广场大了,道路宽了,河道治理了,污水少了,绿化率提高了……     

70 m以上空心高墩施工的温度应力应变控制

介绍了关家沟特大桥工程概况,分析了桥墩轴线的放样施工,提出了施工中消除温度影响的控制技术,并进行了理论计算,对该技术的现场应用情况进行了探讨,得出了该方法正确的结论,为同类工程积累了经验.     

多媒体技术在小学数学教学中的作用

科学技术的日新月异发展,推动了素质教育的进程,多媒体技术已经走进了课堂,本文阐述了小学数学教学应用多媒体技术,激发了学生浓厚的学习兴趣,化解了教学重点难点,营造了良好的氛围,优化了课堂教学,提高了课堂教学效率。     

多媒体-小学数学教学的得力助手

多媒体技术的发展使小学数学教学模式发生了根本性变化。课堂体现了学生的主体性原则,多媒体的应用丰富了教学内容,灵活了教学方式,点燃了学生思维的火花,提高了学生听课效率,有效解决了数学教学中的重难点,多媒体是小学数学教学的得力助手。     

柴油发电机励磁绕组的改进

本文介绍了柴油发电机组励磁系统出现的故障及原因,设计了新的励磁装置,并制定了使用控制措施,通过实践检验,排除了类似故障,从而保证了工程施工的安全、质量、进度和效益,取得了较好的经济效益。     

聚合物改性砂浆耐久性的试验研究

正交试验表明,聚合物干粉改性砂浆相对普通砂浆,折压比增加了69%,粘结强度增长了22.48倍,最大渗透压增加了6个级别,失水率下降了34.8%,干缩率减少了16%,明显改善了砂浆性能.     

大国重器 节能先锋——徐工集团2014成套绿色节能道路机械新品挺进东北

正此次徐工重磅推出的"先进、可靠、节能、高效"成套绿色节能道路机械,不但提高了能源利用率,减少了油耗,进而为用户大幅降低了成本,而且降低了排放,保护了环境,以"节能环保"优势在市场竞争中占据了主动地位。     

小型热回收装置的可行性研究

通过回收排气中的余热对引入空调系统的新风进行预热或者预冷,可以减少空调系统的能耗。分析了不同装置的原理和性能特点以及适用性特征,初步探讨了热回收设备配置的合理性并举例说明了其节能效果,从而论证了应用的技术可行性。提出了一种简易的经济分析计算方法,评价了经济效果,论证了经济可行性。得出了小型热回收装置用于暖通空调系统可行的结论,并展望了乐观的应用前景。     

给水管网漏损的检测措施及原因分析

介绍了管网漏损的检测方法,结合实际描述了相关检测法在检漏中的具体应用,针对漏损进行了成因分析,并提出了相应对策.     

大线径导线恒张力架设技术

研究了高速铁路大线径导线恒张力架设技术,分析了其原理、机械及技术,给出了整套架设方案,实践证明,采用该施工工艺后,提高了施工效率,节约了材料及其他费用,取得了非常理想的效果。     

Zustandsuntersuchung und Instandsetzung am Hauptdach des Hauses der Kulturen der Welt in Berlin

The main roof of the ”Haus der Kulturen der Welt“ in Berlin Which is very well‐known on account of its history and striking structural design – was to be inspected by the author to determine its condition and analysed with regard to the durability of the existing liquid synthetic sealant. The roof structure consists of a biaxial, curved area‐covering structural element with circumferential edge beams of pre‐stressed lightweight concrete. This is the result of the reconstruction between 1984 and 1987 following a partial collapse of the then Berlin Congress Hall in 1980. The very thin roof shell is also made of lightweight concrete and, like the edge beams, has a polyurethane‐based spray‐on seal that was specially developed for this purpose as protection against the ingress of moisture. The reason why this, at the time, novel type of seal was chosen was that it should take into account the fact that the roof design urgently needed some kind of protection against moisture that had to compensate the expected changes shape and crack movements of the roof with no damage. The following article reports on the nature, scope and main results of the analysis of the condition of the roof seal, edge beams and abutments. It will also describe the repair recommendations resulting from the investigations, which form the basis of the execution of work at the present point in time. Apart from presenting the technical principles and special features of the building that have to be taken into account during any repairs, the special features of the execution will also be addressed.     

Magnetoelastische Spannkraftmessung in Bauwerken

Magnetoelastic Measurement of Prestressing Force in Civil Structures The knowledge of the tensile force of prestressing steel elements and its reliable and non‐destructive determination are of essential importance for the assessment of the structural health condition of prestressed concrete structures and tie‐back systems in terms of structural safety, serviceability and durability. For the evaluation of the prestressing force in steel tension members, the measurement technique presented in this contribution is using the magneto‐elastic effect (ME‐effect) of ferromagnetic materials. This effect describes the reverse‐proportional correlation between the mechanical stress and the magnetic properties of ferromagnetic materials. The cylindrical coiled sensors pushed over the tendon and the measuring device developed and practically optimized at the iBMB/MPA of the TU Braunschweig enable a fast and reliable measurement of the prestressing steel force after an initial calibration. In this contribution first the state of the art of prestress measurement techniques for steel tension members is presented. Afterwards, the ME‐measuring method with the basics and merits of magneto‐elastic prestressing force identification is shown. Further recent research results as well as several building applications will be discussed.     

Erfahrungen bei der Beurteilung der Dauerhaftigkeit vorgespannter Bewehrung von älteren Spannbetonbrücken

Experiences due to the evaluation of the durability of prestressed reinforcements in old prestressed concrete bridges. Old prestressed concrete bridge superstructures exhibiting cracks across the prestressed reinforcement need detailed inspections for estimating maintenance requirements. Only this type of evaluation makes it possible to determine the required extent and nature of maintenance. In this paper essential steps of the “Directive of the durability of prestressed reinforcements in old prestressed concrete bridge superstructures” of the Federal Highway Research Institute are explained, also against the effects of growing heavy traffic with expected higher gross weights and axle loads.     

谈贯标中企业如何做好检验和试验工作

根据在贯彻GB／T 19001－ISO9000族标准过程中的实际工作经验,从贯彻中为什么要抓好检验和试验工作入手,对检验和试验依据的管理,检验和试验设计的控制,检验和试验人员的培训,检验和试验记录的填写,保存和分析四个方面进行了论述,阐述了检验和试验工作在贯标中的重要性。     

Colour and turbidity removal with reusable magnetite particles—VII: A colloid chemistry study of the effect of inorganic ions on the efficiency of clarification

The removal of colour and turbidity from natural waters by the addition of magnetite is an interfacial process. Furthermore the components of this system are either of colloidal dimensions or of a surface active nature and thus this method of water clarification is very much in the realm of surface and colloid chemistry. Electrokinetic techniques have been used to examine the influence of a number of inorganic species, commonly encountered in the practical situation, on the surface properties of magnetite and consequently on the efficiency of the process.     

Alternative Methods of Procurement for Works of Water and Environmental Management

The paper considers methods of procurement for the construction of water- and sewage-treatment works other than the traditional use of the ICE 5th Edition Conditions of Contract and Bills of Quantities. This is as a consequence of the speed at which schemes are currently required within the water industry.
The paper particularly focuses on the use of target contracts, using the Institution of Chemical Engineers'Green Book form, and considers various types of target. It also discusses the form which tender documents may take, and how targets may be calculated.
Tendering procedures, including the use of two-stage tenders and negotiated targets, are considered, as are the procedures for cost monitoring and the financial management of the contract. Finally, the role of the engineer and quantity surveyor is considered.     

斜坡失稳的突变模型与混沌机制

针对斜坡平在滑动失稳问题,运用突变理论方法,给出了快速滑坡和慢还滑坡发生的判据,提出了刚度效应失稳新理论,指出刚体极限平衡稳定性评价方法有较大缺陷;根据建立的斜坡演非线性动力学模型,发现外部环境因素的作用一斜坡系统的响应有复杂的非线性关系,当斜坡本身的非线性作用与外部环境因素的作用能力相当时,斜坡化过程会出现混沌现象,其通向混沌之路是通过倍周期分叉实现的。     

River water quality of the River Cherwell: an agricultural clay-dominated catchment in the upper Thames Basin, southeastern England

The water quality of the River Cherwell and a tributary of it, the Ray, are described in terms of point and diffuse sources of pollution, for this rural area of the upper Thames Basin. Point sources of pollution dominate at the critical ecological low flow periods of high biological activity. Although the surface geology is predominantly clay, base flow is partly supplied from springs in underlying carbonate-bearing strata, which influences the water quality particularly with regards to calcium and alkalinity. The hydrogeochemistry of the river is outlined and the overall importance of urban point sources even in what would normally be considered to be rural catchments is stressed in relation to the European Unions Water Framework Directive. Issues of phosphorus stripping at sewage treatment works are also considered: such stripping on the Cherwell has reduced phosphorus concentrations by about a factor of two, but this is insufficient for the needs of the Water Framework Directive.     

Towards Sustainable Landscape Planning: experiences from the Wye Valley Area of Outstanding Natural Beauty

The role of Area of Outstanding Natural Beauty (AONB) partnerships in the planning and management of landscapes is assessed. It is particularly explored how the AONB partnerships can provide focus for environmental planning through their strategies and the role they play in building consensus between different actors. The study is contextualized in light of recent findings from the Countryside Agency Review of AONBs, and the general move in environmental planning towards seeking integrated and sustainable solutions. A case study of the Wye Valley AONB is used in order to explore the types of collective ventures for landscape planning under the themes of landscape planning for visual amenity, planning for sustainable tourism and integrated rural land management.