永济市热电厂150m烟囱爆破拆除

介绍了永济市热电厂150m高烟囱爆破拆除的工程实例。结合待爆烟囱特点和周围环境制定了爆破方案。针对高耸烟囱筒身切口较多可能会导致定向倒塌过程中折断、变向等特点,通过预处理形成导向窗和定向窗,采取加固大体积切口以及割断背部竖筋等措施,辅以毫秒延时起爆、簇联接力复式网路以及安全防护措施,取得了理想的爆破效果,可为类似工程提供参考。     

100 m高钢筋砼烟囱定向爆破拆除

以定向爆破拆除100 m高钢筋砼烟囱为工程实例,论述了烟囱爆破要合理地确定爆破切口部位、选择爆破切口形状和精确地开设对称定向窗等工程经验.     

复杂环境厚壁砖混烟囱拆除的精准定向控制爆破

根据砖混结构烟囱的特点和复杂环境,合理选择烟囱拆除爆破的倒塌方向,确定爆破切口为近等腰梯形,并在切口底部采用控制爆破方式预先开凿定向窗,以实现厚壁砖混结构烟囱拆除的精准定向爆破。实施砖混结构烟囱定向窗的爆破开凿,降低了劳动强度,缩短了开凿时间,提高了开凿准确性。采用竹笆近体防护措施和排栅远体防护措施,防止切口爆破飞散物及落地飞溅的危害,同时采用沙包减振堤降低落地冲击振动,控制了振动危害,取得了预期的爆破效果。对类似工程有较好的参考价值。     

复杂环境厚壁砖混烟囱拆除的精准定向控制爆破

根据砖混结构烟囱的特点和复杂环境,合理选择烟囱拆除爆破的倒塌方向,确定爆破切口为近等腰梯形,并在切口底部采用控制爆破方式预先开凿定向窗,以实现厚壁砖混结构烟囱拆除的精准定向爆破。实施砖混结构烟囱定向窗的爆破开凿,降低了劳动强度,缩短了开凿时间,提高了开凿准确性。采用竹笆近体防护措施和排栅远体防护措施,防止切口爆破飞散物及落地飞溅的危害,同时采用沙包减振堤降低落地冲击振动,控制了振动危害,取得了预期的爆破效果。对类似工程有较好的参考价值。     

砖砌烟囱定向爆破拆除实践

介绍了一座 62m砖砌烟囱定向爆破拆除的实例。为保证烟囱准确定向倾倒 ,采取了一些技术措施 ,这些措施包括采用倒梯形切口减少烟囱爆破时的后坐 ;开设定向窗控制切口范围和形状 ;采用多向闭合起爆网路提高起爆网路可靠性以及内衬预处理等。通过采用微差爆破、开挖减震沟及在地面铺设缓冲材料等 ,降低爆破震动及烟囱触地震动强度。文中论述了爆破方案设计、爆破参数确定以及飞石防护等安全措施 ,并简述了爆破效果。     

复杂环境下高位切口爆破拆除钢筋混凝土烟囱

介绍了在倒塌空间不足的条件下,采用高位切口爆破拆除80m钢筋混凝土烟囱的工程实例。采用了烟囱高位切口支撑断面力学分析模拟计算出烟囱的切口位置和切口角度;采用正梯形切口,开设定向窗,设置缓冲堤,开挖减振沟等措施成功爆破拆除该烟囱。结合爆破效果,初步探讨了烟囱高位切口支撑断面力学分析的结果,可为类似工程提供参考依据。     

定向爆破拆除偏斜烟囱

文章针对偏斜砖结构烟囱的特点和复杂环境条件,论述了为保证烟囱准确定向倾倒而采取了预拆除、优化爆破切口设计、精确开凿定向窗等一系列技术措施.     

定向爆破拆除砖混烟囱

介绍了一座砖混烟囱定向拆除爆破的实例，论述了爆破方案设计，爆破参数确定，爆破切口形状和尺寸．定向窗的开设以及防护措施等施工工艺。     

百米钢筋混凝土烟囱的定向爆破拆除

介绍了百米钢筋混凝土烟囱定向爆破拆除工程的实例 ,论述了爆破方案设计、爆破参数确定、爆破切口的形式和尺寸、定向窗的开设、起爆网路、防护措施以及内衬处理等 ,尤其对施工工艺进行了较为详细的叙述。爆破取得了理想的效果。通过对爆破效果的分析 ,得到了一些有益的启示和实际经验     

风化倾斜砖烟囱定向爆破拆除

某厂有1座砖烟囱,由于时间久远,局部已经发生风化开裂,烟囱整体已出现倾斜.针对风化偏斜砖结构烟囱的实际特点,以及复杂的现场周围环境,通过合理选择切口位置、形状、爆破参数等措施,保证了烟囱爆破拆除设计的合理性,在倾倒方向施加预应力、预先爆破拆除烟囱内衬、人工修整定向窗等措施,确保了烟囱按照预定方向倾倒.     

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.……     

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.……     

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.     

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.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.