倒向受限时水塔的爆破拆除

文中介绍了复杂环境下爆破拆除水塔的一个实例,对水塔定向倾倒受限时如何制定爆破方案,参数设计及安全警戒防护等问题作了叙述。     

倒塌空间不足的水塔爆破拆除

介绍邢台矿业集团36m高大型生活水塔，在倒塌空间不足时，采用折叠控制爆破拆除的过程，通过选择合理的切口参数和微差爆破时间，水塔安全倾倒在预定的空间，对以后类似的工程提供了宝贵的经验。     

薄壳结构水塔定向爆破拆除

薄壳结构水塔有头重脚轻、重心高的特点,为了保证这种结构的定向倒塌,以水塔的定向拆除爆破工程事例,介绍了如何在施工中加速水塔倾倒的技术措施,及施工方案的选取,使水塔爆破后能在在较短时间内倾倒,保证了设计目标的实现.     

无后坐控爆拆除砖砌水塔的实践

介绍了对一砖砌水塔进行无后坐拆除爆破时爆破参数的选取,以及控制后坐的措施.实践证明:用控制爆破方法,选择合理的爆破参数完全可以控制水塔在倾倒时的后坐.     

钢筋混凝土水塔的水压和定向爆破拆除

采用水压爆破和接触爆破定向倾倒技术联合对钢筋混凝土水塔实施拆除,实践证明,该方法施工简单、速度快,爆破解体好、降振和防尘效果显著.介绍了药包的布置和爆破结果的简单分析.     

倾斜水塔的爆破拆除

针对某部倾斜水塔的定向爆破拆除,从防止水塔倾倒偏移和筒体触地冲击地面对周围环境造成影响等不利情况,确定爆破方案和采取相应的防护措施.     

40m高倒锥形钢筋混凝土水塔爆破拆除

介绍了一座薄壁密配筋钢筋混凝土倒锥形水塔爆破拆除,详述了该水塔爆破拆除的设计思路、爆破方案、爆破参数及实际爆破效果,并分析了影响水塔倾倒坍塌速度的原因,提出了类似爆破拆除工程应注意的事项,对于类似简体结构的爆破参数选取具有一定的参考意义.     

38m高倒锥形钢筋砼水塔控爆拆除

介绍了复杂环境下对1座38m高倒锥形水塔的定向控制爆破拆除,论述了倒锥形水塔爆破拆除的爆破设计和爆破切口参数.通过精心组织施工、采取有效的安全防护,水塔起爆后完全按照设计倾倒方向倒塌,爆破产生的飞石和二次飞溅控制较好,未产生飞散危害,达到预期的爆破效果.爆破实践表明,对小直径建(构)筑物的爆破拆除,适当提高切口高度对其顺利倾倒是有利的,值得类似工程爆破中参考.     

40m高倒锥形钢筋混凝土水塔爆破拆除

介绍了一座薄壁密配筋钢筋混凝土倒锥形水塔爆破拆除,详述了该水塔爆破拆除的设计思路、爆破方案、爆破参数及实际爆破效果,并分析了影响水塔倾倒坍塌速度的原因,提出了类似爆破拆除工程应注意的事项,对于类似筒体结构的爆破参数选取具有一定的参考意义。     

40m高倒锥形钢筋混凝土水塔爆破拆除

介绍了一座薄壁密配筋钢筋混凝土倒锥形水塔爆破拆除,详述了该水塔爆破拆除的设计思路、爆破方案、爆破参数及实际爆破效果,并分析了影响水塔倾倒坍塌速度的原因,提出了类似爆破拆除工程应注意的事项,对于类似筒体结构的爆破参数选取具有一定的参考意义。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.