茅台酒厂26层剪力墙结构大楼爆破拆除

根据茅台酒厂钟楼的结构特性、周围环境特点及爆破要求,分析该栋26层高楼的爆破拆除控制要点,采用了单向三折叠的爆破方案。通过爆破方法预先拆除切口内部分剪力墙,有效地降低爆破总药量;通过切口间开设铰链,使大楼在空中充分解体,减小了塌落体的触地块度,从而降低了触地冲击;采用胶皮网覆盖和敷设减振带等防护措施,有效地控制了爆破飞石及触地振动。结合高速摄影对钟楼倒塌后坐造成排污管及排污沟破坏的原因进行了分析,可为类似工程提供参考。     

180m高钢筋混凝土烟囱三段单向控制爆破拆除

对复杂环境下180m高钢筋混凝土烟囱,采用三段单向分次控制爆破拆除。采用复式梯形爆破切口,确保烟囱倒塌方向;铺设黄土缓冲垫层和个体特殊防护措施,有效地控制烟囱倒塌触地振动;采用刚性和柔性复合式措施防控爆破飞石;采用高空吊篮法进行高空爆破切口施工。爆破后,烟囱倒塌方向准确,周边建筑物和设施安然无恙,取得了良好的爆破效果,达到了安全、精细和快速爆破拆除的目的,为以后类似爆破工程提供参考。     

180m高钢筋混凝土烟囱三段单向控制爆破拆除

对复杂环境下180m高钢筋混凝土烟囱,采用三段单向分次控制爆破拆除。采用复式梯形爆破切口,确保烟囱倒塌方向;铺设黄土缓冲垫层和个体特殊防护措施,有效地控制烟囱倒塌触地振动;采用刚性和柔性复合式措施防控爆破飞石;采用高空吊篮法进行高空爆破切口施工。爆破后,烟囱倒塌方向准确,周边建筑物和设施安然无恙,取得了良好的爆破效果,达到了安全、精细和快速爆破拆除的目的,为以后类似爆破工程提供参考。     

复杂环境下110 m冷却塔控制爆破拆除

介绍了一座高110 m的薄壁钢筋混凝土冷却塔的定向控制爆破拆除。针对冷却塔高度大、塔壁薄以及底部直径大的特点,采用“开窗口、断钢筋、预留支撑板块”爆破方案,预拆除中通过对冷却塔爆破缺口进行优化设计,在爆破边沿开设2个简化的定向窗。在爆破区域仅对冷却塔人字柱底部和顶部进行布孔爆破,将爆破切口分为5个起爆区域采用分区分段的非电毫秒延期起爆技术。为了有效控制爆破危害效应,在冷却塔倒塌方向铺设缓冲土层及钢板进行双重防护有效地降低了塌落冲击振动,在爆破切口处采用密目网和土工格栅覆盖相结合的防护措施有效地控制了飞石,未对周围建(构)筑物造成损害。爆破效果表明：在爆破切口边沿开设2个简化的定向窗窗口,不仅减少了钻孔及相关工作量,降低了安全隐患和防护难度,而且提高了预处理部分的结构稳定性,防止爆破切口处下坐;通过对定向窗的简化设计,使得冷却塔在倾倒过程中发生扭曲充分解体,爆堆较为集中,触地振动较小,爆破效果良好。     

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。     

分段控制爆破技术在210m烟囱拆除中的应用

根据国家相关政策,某电厂现有一座高210 m烟囱需要进行爆破拆除。介绍了分段控制爆破技术在实际工程中的具体应用。通过在烟囱100 m处和底部开设倒梯形爆破切口、梅花形布孔,确保烟囱倒塌方向;爆破采用毫秒延时起爆、在烟囱倒塌方向开挖减震沟、烟囱触地地面铺设松软黄土缓冲层、倒塌方向三面搭设防护屏障等措施有效地控制了爆破振动和飞石危害,达到了比较理想的效果。     

茅台酒厂朱旺沱宾馆12层大楼爆破拆除

针对朱旺沱宾馆倒塌长度有限,周围建筑及物品抗震性能较差的实际情况,采用单向三折叠爆破技术;对爆破切口处的梁以及切口外立柱、梁进行钻孔松动破坏;通过捆扎胶皮网、开挖多条减震沟、铺设柔性缓冲层的方法对爆破飞石、触地振动进行了控制,爆破拆除达到了预期效果。     

19层楼房单向折叠爆破拆除

通过4切口单向折叠爆破拆除技术成功爆破19层楼房.工作中通过人工加机械的方法预先拆除切口处砖墙和部分剪力墙,“化墙为柱”有效地降低了工程量和爆破量;在最后一排立柱间的预制板上开1条15 cm宽的缝有利于楼房的轴向运动,对楼房倾倒方向的控制起到了至关重要的作用.特别针对楼房高度高,自重大的特点,设计了3条0.5m×1.5m×60m以黄沙堆砌的缓冲带,成功地将楼房倒地的触地振动控制在安全范围之内.除合理安排单响起爆药量外在保护体与振源之间开挖减振沟可以有效地保证触地振动和爆破振动不会伤害周围建筑.     

两座55m高钢筋混凝土烟囱定向爆破拆除

为了成功爆破拆除复杂环境下两座相距10m的55m高钢筋混凝土烟囱,采用精细化爆破技术,选取合理的爆破参数及爆破切口形状,精心组织施工。同时,为了防止两座烟囱同时触地引起较大的塌落触地振动,采取孔外延时、依次起爆的起爆网路,确保两座烟囱按预定设计方向顺序倾倒。通过设置减振带、采取消防车洒水、爆破切口近体防护及重点建筑物遮挡等有效的安全防护措施,确保烟囱塌落触地振动及爆破飞石等爆破有害效应控制在安全允许范围内。烟囱的爆破拆除达到了设计效果,可为类似工程提供参考。     

85m高的烟囱拆除爆破及其振动测试分析

为了验证爆破方案设计的合理性,介绍了广州油制气厂85m高钢筋混凝土烟囱的定向拆除爆破,同时分析了现场环境和影响倒塌的因素。在实施拆除爆破的设计方案时,沿烟囱倒塌方向前后、侧方及周围厂房布置共计11个测点,对此次拆除爆破进行全程振动监测。通过对实测振动信号和数据分析比较,发现在拆除爆破过程中,距离爆源较近处的爆破振动大于塌落触地振动;塌落触地振动强度不仅与振中距有关,而且测点方位对其也有着重要的影响;通过对测试数据拟合分析,发现减振沟和负高差地形能有效地降低振动强度。该研究为改进和优化拆除爆破方案,利用地形条件选择爆破倾倒方向,降低振动效应对周围环境影响具有一定的参考价值。     

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.