聚能切割在水库放空应急抢险中的应用

湖北某水库导流洞放空钢管闸阀因故障无法正常开启,对水库运行造成了极大的安全隐患,需采取有效措施放空水库以便在汛前完成闸阀抢修.根据工程特点和抢险需求,设计采用聚能爆破方法对放空钢管进行切割,并对环形切割和局部矩形切割的两种聚能切割方案进行了比选.根据拟采用的聚能切割器材料和几何形状,利用ANSYS/LS-DYNA对聚能切割效果进行模拟,以穿透钢板后的射流速度作为聚能切割效果的评价指标,确定了该切割器(顶宽6 mm、底宽30 mm、高25 mm、聚能罩夹角90°)的最佳炸高为13～17 mm,并进行了爆破切割模拟试验.对实际工程中聚能切割器的起爆方式、安装施工及爆破切割效果等进行了较为详细的介绍.实践证明线装药密度为380 g/m的聚能切割器可成功切割壁厚14～16 mm的钢管,为类似抢险除险工程的爆破切割提供了可供参考的成功范例.     

新型水下爆破切割弹在卡钻事故中的应用

针对安庆铜矿某一矿井的卡钻事故,在分析卡钻原因的基础上,结合井下地质情况,设计一种新型水下爆破切割弹.采用熔融的钝化黑索金浇铸装药,提高炸药的能量密度;加入12根铜管形成了环形切割器,利用聚能射流侵彻钻杆以达到破坏钻杆的目的.通过爆破切割实验和工程实践可知,新型水下爆破切割弹能够有效解决卡钻事故.     

桁架结构厂房房顶聚能切割爆破拆除

根据钢筋混凝土桁架结构厂房房顶的结构特点,在保证行车轨道等设施不被破坏的条件下,利用聚能切割技术对其关键部位实施切割爆破。施工中采用了双侧对称爆破切割方案,使房顶结构失稳并一次性塌落。本文介绍了线型聚能切割器参数设计、零炸高试验、起爆网路及安全防护措施,讨论了聚能切割爆破的设计和实施中应注意的问题。同时,简述了利用聚能切割技术拆除大型桁架式构筑物的效果和体会。     

聚能切割技术在水平井连续油管切割中的应用

将环形聚能切割技术应用于水平井连续油管遇卡事故处理中,可以解决连续油管在水平井中的遇卡事故。针对2英寸连续油管的特点,设计了一种聚能切割弹及连接装置马笼头,主要从切割弹结构设计、药型罩结构设计、装药选择、马笼头结构设计及施工工艺等方面进行了研究。通过地面切割试验、现场应用,设计的聚能切割装置,及电缆传输工艺实现了水平井中遇卡连续油管的切割解卡,操作简便、施工安全。     

聚能切割技术在水平井连续油管切割中的应用

将环形聚能切割技术应用于水平井连续油管遇卡事故处理中,可以解决连续油管在水平井中的遇卡事故。针对2英寸连续油管的特点,设计了一种聚能切割弹及连接装置马笼头,主要从切割弹结构设计、药型罩结构设计、装药选择、马笼头结构设计及施工工艺等方面进行了研究。通过地面切割试验、现场应用,设计的聚能切割装置,及电缆传输工艺实现了水平井中遇卡连续油管的切割解卡,操作简便、施工安全。     

松花江旧铁路大桥的爆破拆除技术

介绍长1382 6m松花江旧铁路大桥控制爆破拆除的设计与施工。根据该桥的环境和结构特点,采用了线形聚能装药切割技术和深孔爆破相结合的方法,拆除水面以上的钢结构梁和桥墩。文中概述了桥梁的结构、工程特点和总体爆破方案;讨论了线形聚能装药的参数、设置方法以及深孔爆破的布孔参数、装药结构、起爆方法。同时介绍了钢桁架结构的预处理和安全防护措施。     

松花江旧铁路大桥的爆破拆除技术

介绍长1382 6m松花江旧铁路大桥控制爆破拆除的设计与施工。根据该桥的环境和结构特点,采用了线形聚能装药切割技术和深孔爆破相结合的方法,拆除水面以上的钢结构梁和桥墩。文中概述了桥梁的结构、工程特点和总体爆破方案;讨论了线形聚能装药的参数、设置方法以及深孔爆破的布孔参数、装药结构、起爆方法。同时介绍了钢桁架结构的预处理和安全防护措施。     

变截面悬链线箱型无铰拱桥切割爆破拆除

某中承变截面悬链线箱型无铰拱桥,因部分已出现裂缝和公路建设的需要,必须拆除。通过试验研究,并根据桥以钢结构为主的特点,采用TNT/PENT(40/60)的聚能药包对钢结构实施爆破切割。文中介绍了爆破方案的选择、预处理和切割爆破的设计、起爆网路以及安全技术措施。此外还介绍了自行设计的聚能切割器及其在钢结构上的固定方法。     

变截面悬链线箱型无铰拱桥切割爆破拆除

某中承变截面悬链线箱型无铰拱桥,因部分已出现裂缝和公路建设的需要,必须拆除。通过试验研究,并根据桥以钢结构为主的特点,采用TNT/PENT(40/60)的聚能药包对钢结构实施爆破切割。文中介绍了爆破方案的选择、预处理和切割爆破的设计、起爆网路以及安全技术措施。此外还介绍了自行设计的聚能切割器及其在钢结构上的固定方法。     

线型聚能切割器在工程爆破中的应用研究

以线型聚能装药切割器技术在某爆破工程中应用的实例,分析了线型聚能射流切割目标的原理及影响因素,提出了对于一般常用钢构件材料条件下工程爆破采用线型聚能切割器的参数设计方法,进而展望了此器材在工程爆破中应用的发展前景.     

Differences in coagulation in clotting of vascular access in hemodialysis patients

Arteriovenous graft (AVG) thrombosis is a frequent cause of graft failure. We evaluated coagulation protein concentrations, platelet function, and viscoelasticity factors in 20 hemodialysis (HD) patients with AVGs. The goal was to determine whether significant differences in protein concentrations, platelet function, and viscoelasticity factors exist among dialysis patients requiring frequent AVG declot procedures vs. those who do not. Twenty HD patients were enrolled: 10 frequent clotters (>3 declots in the previous year) and 10 were nonclotters. Patients on antiplatelets or chronic anticoagulation were excluded. Laboratories were drawn pretreatment and heparinase was added to counteract any potential heparin effect. Coagulation protein concentrations including tissue factor (TF), thrombin/antithrombin III complex (TAT), and prothrombin fragment 1 + 2 (F₁₊₂) were assayed. The time to clot onset was measured by force onset time (FOT). Platelet contractile force (PCF) measured the force produced by platelets during clot retraction, whereas clot rigidity was measured as clot elastic modulus (CEM). FOT, CEM, and PCF were measured by Hemodyne. Both groups had upregulation of the TF pathway, as TF, TAT, and F₁₊₂ levels were similarly increased over baseline levels. Hemodialysis patients with frequent AVG clotting had higher levels of both PCF and CEM compared with nonclotters. Additionally, the frequent clotters had a lower FOT relative to nonclotters, although both were considered in the normal range. Our study suggests that HD patients with recurrent AVG thrombotic events form clots with higher tensile strength compared with HD patients without recurrent graft thrombosis.     

Trends in alcohol-impaired driving in Canada

While a general decreasing trend in the number of persons killed in a traffic crash involving a drinking driver has occurred in Canada since the 1980s, it is evident that much of this decrease occurred in the 1990s. Since 2002, less progress has been made as the number of persons killed in crashes involving drinking drivers remains high. To better understand the current situation, this paper describes trends in drinking and driving in Canada from 1998 to 2011 using multiple indicators based on data collected for the Traffic Injury Research Foundation's (TIRF) Road Safety Monitor (RSM), the National Opinion Poll on Drinking and Driving, and trends in alcohol-related crashes based on data collected for TIRF's national Fatality Database in Canada. There has been a continued and consistent decrease in the number of fatalities involving a drinking driver in Canada. This remains true when looking at the number of fatalities involving a drinking driver per 100,000 population and per 100,000 licensed drivers. This decreasing trend is also still apparent when considering the percentage of persons killed in a traffic crash in Canada involving a drinking driver although less pronounced. Data from the RSM further show that the percentage of those who reported driving after they thought they were over the legal limit has also declined. However, regardless of the apparent decreasing trend in drinking driving fatalities and behaviour, reductions have been relatively modest, and fatalities in crashes involving drivers who have consumed alcohol remain high at unacceptable levels.     

Flow-Induced Instabilities in Pump-Turbines in China

The stability of pump-turbines is of great importance to the operation of pumped storage power (PSP) stations. Both hydraulic instabilities and operational instabilities have been reported in PSP stations in China. In order to provide a reference to the engineers and scientists working on pump-turbines, this paper summarizes the hydraulic instabilities and performance characteristics that promote the operational instabilities encountered in pump-turbine operations in China. Definitions, analytical methods, numerical and experimental studies, and main results are clarified. Precautions and countermeasures are also provided based on a literature review. The gaps between present studies and the need for engineering practice are pointed out.     

Gender differences in publication productivity in psychology in India

An analysis of gender differences in psychology in India provides quantitative and qualitative assessment of R&D output contributed by psychologists with the indication of the trend of growth, skewness, relatedness, co-authorship pattern of productivity.     

Metrology in Chemistry in Germany

The system for Metrology in Chemistry in Germany is described. At the national standards level, a network of high-level chemistry institutes coordinated by the national metrology institute, PTB, provides the primary references for chemical measurements. A dissemination mechanism employs chemical calibration laboratories accredited within the framework of the German Calibration Service (DKD). They act as “multipliers” between the national standards level and the user level by providing the user with calibration means which are traceable to the SI via national standards. Traceability structures in clinical chemistry, electrochemistry, elemental analysis and gas analysis are described     

陶瓷超塑性的研究进展

本文综述了氧化锆及其复相陶瓷超塑性的研究现状，论述了陶瓷超塑性的变形机理，微观特征和断裂特性。同时，分析和对比了陶瓷超塑性与金属超塑性的特点。目前，对于正确理解超塑性陶瓷的变形机理，还需进行大量工作。     

离子液体中电沉积的研究进展

离子液体作为绿色溶剂和可设计性溶剂越来越受到重视.对电沉积来说,离子液体融合了高温熔盐和水溶液的优点.分别综述了AlCl3型离子液体、非AlCl3型离子液体和其他新型离子液体3类离子液体中电沉积的研究现状,在此基础上指出了目前尚存在的问题及今后的研究方向.采用离子液体进行电沉积能克服传统水溶液电沉积时存在的缺点,为电沉积领域找到了新的突破点,是一种很有应用前景的方法.     

高聚物银纹化的研究进展

结合最新的研究进展,对银纹引发、生长与断裂,银纹细观结构以及裂纹在银纹中的扩展等问题作了较全面的介绍和分析,对这一领域未来的研究方向和重点进行了展望。     

Ecological compensation in spatial planning in Italy

Ecological compensation or biodiversity offsets are increasingly recognized as a key element for environmental sustainability; however, more attention has been paid so far to compensation applied at the project level rather than to spatial planning. Meanwhile, there is a growing acknowledgement that extensive environmental depletion is being caused by the cumulative effects of small developments allowed by spatial/land use plans. This paper aims to collect empirical evidence on the requirements for ecological compensation at a strategic level of decision-making – spatial planning – in Italy. Results indicate that spatial plans are increasingly introducing offset requirements for residual impacts of new urban developments; however, methodological and operational aspects are not sufficiently addressed and enforcement mechanisms appear weak. The lack of legal frameworks and of established methods appears to be the main element currently hindering biodiversity offset implementation at the planning level. It is suggested that, in the Italian context, a way to foster better implementation is the design of environmental stewardship schemes involving farmers, developers and planning authorities.