A reliability-based data treatment system for actual load history

This paper seeks to establish an integrated and practical data treatment system for actual load history reliability analysis. A convergence–divergence counting procedure is presented to extract all load cycles from a load history of divergence–convergence waves. The lowest number of load history sampling is established on the basis of the damage‐based prediction criterion. A parameter estimation formula is proposed for hypothesis testing of the load distribution. The examples of its application for the data treatment of actual load history are given. The proposed data treatment system has been shown to have valid and practical characteristics in analysing reliability results.     

Assessing technologies for reducing dust emissions from sintermaking based on cross-media effects and economic analysis

Clean Technologies and Environmental Policy - The Industrial Emission Directive (IED) requires industrial establishments to apply the best available techniques (BATs), and competent environmental...     

大型浅埋隧道爆破工程安全管理模式

从中国大连地铁1、2号线建设的实际情况出发,介绍了一种大型浅埋隧道爆破工程安全管理模式。首先结合线路分布图对重大风险源进行识别、重点控制;然后从技术层面上进行施工前爆破安全论证评估;同时采用专家咨询或现场指导的方式动态解决了工程遇到的难题。为了将爆破振动速度的控制引入爆破振动监测体系,针对爆破施工的特殊性,制定了爆破施工安全管理细则。经过四年的工程实践,爆破安全管理问题得到了很好的控制,该安全管理模式可为未来城市浅埋轨道交通及相关工程提供参考。     

大型浅埋隧道爆破工程安全管理模式

从中国大连地铁1、2号线建设的实际情况出发,介绍了一种大型浅埋隧道爆破工程安全管理模式。首先结合线路分布图对重大风险源进行识别、重点控制;然后从技术层面上进行施工前爆破安全论证评估;同时采用专家咨询或现场指导的方式动态解决了工程遇到的难题。为了将爆破振动速度的控制引入爆破振动监测体系,针对爆破施工的特殊性,制定了爆破施工安全管理细则。经过四年的工程实践,爆破安全管理问题得到了很好的控制,该安全管理模式可为未来城市浅埋轨道交通及相关工程提供参考。     

Sixty years of engineering blasting in China: review and prospect

Based on representative blasting engineering examples, the development history of engineering blasting in China since 1950s was reviewed, three development phases were summarized, main achievements of fundamental theory, engineering practice, scientific study and industry organization of engineering blasting in each phase were introduced briefly. Finally, some suggestions about the development direction of engineering blasting in China were given.     

让工程爆破技术更好地服务社会、造福人类——我国工程爆破60年回顾与展望

结合典型爆破工程,回顾了我国工程爆破自20世纪50年代以来的发展历史,将其总结为"起步、成长、壮大"三个阶段,简要介绍了各阶段工程爆破基础理论、工程实践、科学研究和行业组织的主要成果。并对我国工程爆破行业未来的发展方向进行了展望。     

盐岩能源地下储备库群风险综合评价与管理体系

利用盐岩洞穴进行能源地下储备是我国能源储备的重点战略部署方向。我国盐岩地层埋深浅,呈层状分布,且夹层较多,地质条件相对复杂,增加储库灾变的可能性,因此建立一套盐岩能源地下储备库群风险综合评价和管理体系尤显重要。根据盐岩地下储库群灾变事故的统计结果,获取了盐岩地下储库的主要风险因子,对库群风险进行了辨识。建立了盐岩地下库群风险评价方法和风险分级标准,通过数值模拟方法对失效概率进行了核算,评价了金坛盐岩库群风险等级,并通过模型试验对结果进行了验证,开发了基于计算机网络技术的盐岩地下库群风险信息管理与评估系统,建立了盐岩能源地下储备库群风险综合评价和管理体系。     

隧道钻爆法水封装药结构爆破引起振动计算分析

装药结构是影响爆破振动效应的一个主要因素,针对隧道钻爆法施工中常见的水封爆破装药结构以Heelan短柱状药包激发引起远场质点运动理论解为基础,将该种装药结构分为炸药段和水介质段,并假定爆源远场质点最大振速主要由两段孔壁压力叠加作用引起,求得远场位置处振动速度解析解,并通过现场实测数据进行了验证,同时针对爆破振动影响因素进行了分析。研究结果表明:理论计算值与实测数据存在一定误差,但能满足工程要求,可用于指导施工;水介质段对围岩的作用主要由水介质段的长度和对孔壁的径向压力决定,水介质段长度与炸药段长度的比例直接影响水介质段作用产生的爆破振动数值及在爆破振动总效应中的比例;由于水介质段本身作用强度较小,在远场作用不明显,适于预测和评价爆破近场爆破振动速度。     

基于地质雷达与孔内摄像的爆破防漏施工方法

为了解决在裂隙溶洞岩体条件下,散装炸药由于良好的流动性,容易发生炸药泄漏,形成安全隐患并影响爆破效果的问题。结合具有典型喀斯特地貌特征的贵阳龙洞堡机场三期扩建工程中露天爆破施工的实际情况,以检测数据为基础,提出了一种适用于不良地质条件的散装炸药施工新方法。设计前,对爆区采用地质雷达进行地质检测,探测地下溶洞等不良构造,基于探测数据有针对性的进行爆破设计;使用孔内摄像技术对炮孔内部条件进行检测,从而确定可能发生炸药泄漏的位置。在施工过程中,采用分段装药、包装炸药隔离、高强度聚乙烯膜柔性隔离等技术控制炸药泄漏。在龙洞堡机场扩建工程的露天爆破中应用结果表明,合理运用该技术,可以有效避免混装炸药因泄漏而流失,从而改善裂隙岩体条件的爆破效果。     

基于地质雷达与孔内摄像的爆破防漏施工方法

为了解决在裂隙溶洞岩体条件下,散装炸药由于良好的流动性,容易发生炸药泄漏,形成安全隐患并影响爆破效果的问题。结合具有典型喀斯特地貌特征的贵阳龙洞堡机场三期扩建工程中露天爆破施工的实际情况,以检测数据为基础,提出了一种适用于不良地质条件的散装炸药施工新方法。设计前,对爆区采用地质雷达进行地质检测,探测地下溶洞等不良构造,基于探测数据有针对性的进行爆破设计;使用孔内摄像技术对炮孔内部条件进行检测,从而确定可能发生炸药泄漏的位置。在施工过程中,采用分段装药、包装炸药隔离、高强度聚乙烯膜柔性隔离等技术控制炸药泄漏。在龙洞堡机场扩建工程的露天爆破中应用结果表明,合理运用该技术,可以有效避免混装炸药因泄漏而流失,从而改善裂隙岩体条件的爆破效果。     

渤海海峡隧道竖井钻爆法施工风险分析及对策研究

针对拟建的渤海海峡隧道竖井施工进行风险分析,确定了施工期间的风险并结合风险权重分析排序,依次为支护结构失效风险最小、自然灾害风险较大、竖井开挖风险最大,并通过风险评估确定了突水、突泥风险为关键风险。综合考虑关键风险与其他风险对竖井施工的影响,从地质预报、竖井吊装设备的选择与吊装过程控制、竖井开挖风险控制、自然灾害风险的预防、竖井支护结构的质量控制以及建立竖井施工作业安全制度等方面提出了对渤海海峡隧道竖井施工风险的应对措施,为后续施工提供参考。     

Modeling system behavior for risk and reliability analysis using KBARM

With advances in technology and the growing complexity of technological systems, the job of the reliability/system analyst has become more challenging as they have to study, characterize, measure and analyze the behavior of systems with the help of various traditional analytical (mathematical and statistical) techniques, which require knowledge of the precise numerical probabilities and component functional dependencies, information which is difficult to obtain. Even if data are available they are often inaccurate and are thus subject to uncertainty, i.e. historical records can only represent the past behavior and may be unable to predict the future behavior of the equipment. To cope with such situations, the knowledge‐based approximate reasoning methodologies (KBARMs) provide necessary help. Among them, the fuzzy and grey methodologies are the most viable and effective tools for coping with imprecise, uncertain and subjective information in a consistent and logical manner. In this paper, the authors present a methodological and structured approach (which makes use of both qualitative and quantitative techniques) to model, analyze and predict the failurebehavior of two units, namely the forming and press units of a paper machine, using KBARMs. Various system parameters such as repair time, failure rate, mean time between failures, availability and expected number of failures are computed to quantify the system behavior in terms of fuzzy, crisp and defuzzified values. Furthermore, a risk ranking approach based on fuzzy and grey relational analysis is discussed to prioritize various failure causes associated with the components in failure mode and effects analysis (FMEA). Copyright © 2007 John Wiley & Sons, Ltd.     

某引水工程取水口围堰和预留岩坎拆除爆破

某引水工程取水口前端预留岩坎与已建水库相连,距离取水口塔体和已建大坝较近,为确保周边建筑物安全,拆除时先进行预留岩坎迎水坡爆破剥离,减少其厚度,再对混凝土围堰和剩余预留岩坎进行分层分区拆除爆破。爆破施工中采取了有效的安全爆破控制技术措施,降低了施工难度,保证了施工质量,达到了预期的效果。通过分层分区拆除爆破,有效解决了围堰和预留岩坎在大型水库水下淹没深度较深且不需人为降低水库水位进行拆除爆破的难题,为今后类似工程积累了宝贵的经验。     

基于物元分析与云模型的地下工程围岩稳定性评价

针对以往地下工程岩体质量评判过程中存在的模糊性与随机性问题,根据岩石质量指标、岩石单轴饱和抗压强度、岩体完整性系数、结构面强度系数和地下渗水量这5项指标建立地下工程围岩稳定性评价指标体系.基于物元分析法,通过计算专家评判矩阵的效度物元及合成权重物元来确定评价指标的重要性.根据确定的评价标准,得到各评价因子隶属于各级别的综合云模型,并针对广州抽水蓄能电站二期地下工程岩体实测数据,先通过正向云发生器计算各评价因子所对应的各个评价级别的隶属度,再与其权重结合得到合成隶属度,然后以最大隶属度为依据判别出岩体稳定性所属级别.将该方法所得评价结果与约简概念格-模糊优选评判法、粗糙集-逼近理想解的排序法(RS-TOPSIS)进行对比,三者判别等级一致,表明该方法准确可靠,且免除了对大量样本的学习过程,能够克服评价指标定性语言和定量数值相互转换所产生的模糊随机性,可以用于地下工程岩体稳定性的评判.     

A four-way catalytic system for control of emissions from diesel engine

The pollution caused by diesel-fuelled vehicles has become a subject of global concern. Presently, various separate technologies such as diesel oxidation catalyst, diesel particulate filter, selective catalytic reduction and ammonia selective catalytic reduction are used to control these pollutants. The four-way catalytic (FWC) system integrates all the separate control systems into a single compact unit. FWC technique using a combination of oxidation–reduction catalysts under various strategies has been investigated to simultaneously remove CO, HC, PM and NOx emitted from diesel engines. An oxidation catalyst (La_0.6K_0.4CoO₃) was prepared by two different methods (sol–gel and co-precipitation). The reduction catalysts: Ag/Al₂O₃ and Cu-ZSM5 were synthesized by impregnation and ion-exchange method, respectively. The FWC was characterized by N₂-sorption, X-ray diffraction, Fourier transform spectroscopy and scanning electron microscopy. The catalytic activities of FWC containing double-layer of catalysts were evaluated in a fixed-bed-tubular-reactor. The highest catalytic activity resulted by the two-layered system of La_0.6K_0.4CoO₃ (sol–gel)?+?Cu-ZSM5 showing 100% NO conversion to N₂ at 415°C, maximum-temperature of soot-combustion at 410°C, complete C₃H₈ conversion at 450°C and 100% CO conversion at 388°C. Maximum NO conversion was maintained up to 427°C; conversion started decreasing with further increase in temperature and 75.4% conversion remained up to 450°C. The performance of double-layered-catalytic-system was as follows: La_0.6K_0.4CoO₃(sol–gel)?+?Cu-ZSM5?>?La_0.6K_0.4CoO₃(sol–gel)?+?Ag/Al₂O₃?>?La_0.6K_0.4CoO₃(co-ppt)?+?Ag/Al₂O₃?>?La_0.6K_0.4CoO₃(co-ppt)?+?Cu-ZSM5.     

Applying a risk assessment approach for cost analysis and decision-making: a case study for a basic design engineering project

Abstract

Many uncertainties and cost variations occur in the work activities of a project, thereby causing many possibilities of under-estimating or over-estimating for a bid price. A comprehensive study for each process of risk management should be investigated to achieve project objectives. However, a limited number of studies have a comprehensive viewpoint to indicate the benefits of risk management and the effect on project performance for the engineering design stage of engineering–procurement–construction (EPC) projects, especially in the basic design stage. This research was conducted to identify and analyze the risks associated with a Basic Design Engineering (BDE) project for a high value-added petrochemical plant in Taiwan. First, a project risk management work flow was proposed as an effective tool to minimize the project risks and maximize the management capacity of practitioners. Second, the cost effect of project risks was described by conducting a case study for the design process of a high value-added petrochemical plant using a Monte Carlo simulation. A risk register was identified to support the data required for conducting simulation analysis. The results of this paper provide reference points for risk management planning of project execution and help project managers evaluate particular risks at the engineering design stage of EPC projects to avoid cost overruns.     

工程爆破引起的振动速度计算经验公式及应用条件探讨

论文分析总结了工程爆破界对于爆破振动速度计算的经验公式。根据相似理论,推导了爆破振动速度计算的公式。研究结果发现,在地形、地质和使用炸药种类不变的情况下,爆破引起的地面振动速度与最大起爆药量Q、爆源距测点的直线距离R、以及爆破作用指数n有关。只有在集中药包、标准抛掷爆破条件下,爆破振动速度的计算公式,才适合于前苏联学者萨道夫斯基提出的经验公式。论文把深孔直列药包,假定为无数个等效集中药包,提出了深孔爆破的振动速度计算公式,并进行了工程实际应用     

I2QFD: A blackboard-based multiagent system for supporting concurrent engineering projects

Although Concurrent Engineering has been accredited as a superior approach to product development, its intrinsic complexity in coordinating the multidisciplinary project team is further augmented when team members are remotely distributed. Assuming the teamwork is supported by an Intranet, this paper proposes the framework of a blackboard-based multiagent system, called I 2 QFD, to facilitate the communication and coordination of the design projects. Configured within a hierarchical structure, this system is defined with IDEF0 and high-level Petri nets to depict the operations of Intelligent Agencies and their affiliated agents. Based on temporal logic, the operation of the project team with I 2 QFD is simulated to manifest the dynamics of the design process as well as to generate the project's schedule that ensures the intended concurrency.     

Simulation analysis and engineering application of distribution characteristics about multi-stage atomization field for cutting dust in fully mechanized mining face

To improve the dust suppression efficiency of the external spray systems of shearers, a dust reduction method consisting of shearer external multi-stage atomization and dust removal fan was proposed. Computational fluid dynamics-based numerical simulation was combined with atomization experiments to analyze the migration and distribution of the cutting dust and multi-stage atomization field under airflow at the 2307 fully mechanized mining face of the Tangkou mine. The results show that with adding dust removal fan and multi-stage atomization points, the peak area of wind speed appeared on both sides of the shearer, and the wind speed was greater than 2.7 m/s, the dust concentration on the downside side of the shearer decreased, the spray coverage area increased significantly, and the droplet concentration at the shearer drum was the largest, exceeding 0.05 kg/m³. According to the research results, the multi-stage atomization arrangement of single-fluid water nozzles of shearer was put forward, and the field application was carried out. Compared with the engineering application results of the single-stage atomization dust suppression system, the total dust reduction rate of the synergistic effect of multi-stage atomization external spray with dust removal fan for the shearer is 87.12%, which is 38.59% higher than that of the conventional single-stage atomization dust suppression system.     

A selective strategy for shakedown analysis of engineering structures

Determining the load‐bearing capacity of engineering structures is essential for their design. In the case of varying thermo‐mechanical loading beyond the elastic limit, the statical shakedown analysis constitutes a particularly suitable tool for this. The application of the statical shakedown theorem, however, leads to a nonlinear convex optimization problem, which is typically characterized by large numbers of variables and constraints. In the present work, this optimization problem is solved by a primal–dual interior‐point algorithm, which shows a remarkable performance due to its problem‐tailored formulation. Nevertheless, the solution procedure remains still a demanding task from computational point of view. Thus, the aim of this paper is to tackle the task of solving large‐scale problems by use of a new so‐called selective algorithm. This algorithm detects automatically the plastically most affected zones within the structure, which have the highest influence on the solution. The entire system is then reduced to a substructure consisting of these zones, based upon which a new optimization problem can be set up, which is solved with significantly less effort. Consequently, the running time decreases drastically, as is shown by application to numerical examples from the field of power plant engineering. Copyright © 2013 John Wiley & Sons, Ltd.