Fire safety of thermoplastic polyurethane based on pyromellitic dianhydride

In this paper, pyromellitic dianhydride (PMDA) was firstly used as fire safety agent for thermoplastic polyurethane (TPU). And, the fire safety improvement of PMDA in TPU was intensively investigated by limiting oxygen index (LOI), smoke density test (SDT), cone calorimeter test, and thermogravimetric/infrared spectroscopy, respectively. It has been found that PMDA could significantly improve the ignition level, and the LOI value increase to 28.5% when 8.0 wt% PMDA was incorporated into TPU; PMDA also could effectively suppress the smoke production and heat release during the combustion process. The peak heat release rate and total smoke release of the sample with 8.0 wt% PMDA were decreased by 68% and 22% compared with pure TPU in cone calorimeter test. The thermogravimetric/infrared spectroscopy results showed that PMDA could improve the thermal stability of TPU composites at high temperature and increased the release of CO₂, H₂O, and so on. All results confirmed that PMDA would have a good prospect in reducing the fire hazard of TPU.     

Reliability of design approaches for axially loaded offshore piles and its consequences with respect to the North Sea

In the near future, several offshore wind farms are planned to be built in the North Sea. Therefore, jacket and tripod constructions with mainly axially loaded piles are suitable as support structures. The current design of axial bearing resistance of these piles leads to deviant results regarding the pile resistance when different design methods are adopted. Hence, a strong deviation regarding the required pile length must be addressed. The reliability of a design method can be evaluated based on a model error which describes the quality of the considered design method by comparing measured and predicted pile bearing resistances. However, only few pile load tests are reported with regard to the boundary conditions in the North Sea. This paper presents 6 large-scale axial pile load tests which were incorporated within a new model error approach for the current design methods used for the axial bearing resistance, namely API Main Text method and cone penetration test (CPT)-based design methods, such as simplified ICP-05, offshore UWA-05, Fugro-05 and NGI-05 methods. Based on these new model errors, a reliability-based study towards the safety was conducted by performing a Monte-Carlo simulation. In addition, consequences regarding the deterministic pile design in terms of quality factors were evaluated. It is shown that the current global safety factor (GSF) prescribed and the partial safety factors are only valid for the API Main Text and the offshore UWA-05 design methods; whereas for the simplified ICP-05, Fugro-05 and NGI-05 design methods, an increase in the required embedded pile length and thus in the GSF up to 2.69, 2.95 and 3.27, respectively, should be considered to satisfy the desired safety level according to DIN EN 1990 of β = 3.8. Further, quality factors for each design method on the basis of all reliability-based design results were derived. Hence, evaluation of each design method regarding the reliability of the pile capacity prediction is possible.     

提升机启动操作中制动油泵软性停转的分析与排除

同一个多功能集控器件长期使用后，其不同故障程度对应有不同故障现象，为了加快现场技术管理人员对提升机疑难故障的有效排除进度，着重分析了制动油泵停转的控制通道，根据提升机启动操作中制动油泵停转后的排查处理结果，圈定了故障范围为变频控制器件。制动油泵在提升机启动操作中停转的不确定性，查找故障时整机电控系统处于非故障状态，接近更换变频主控板D6时启动提升机操作中制动油泵软性停转次数有所增多、启动中无发生制动油泵停转的全程提升未见异常，上述因素使制动油泵软性停转成为疑难杂症。故障现象恶化为每次操作至制动手把推向松闸位置制动油泵均停转，用梯形图确定D6故障是症结所在。对D6的自身故障精确定位功能且在变频控制柜人机界面RJ2显示故障信息认识不足，导致故障长时存在。此副井提升机有关人员应做到:对故障反映到位、深刻了解器件性能特征、透析有关动作过程后方可采取针对性措施、确定故障元件、最终排除故障。可恢复性的轻故障发生后必须采取相应措施，避免故障扩大导致停机延误提升。将变频就绪与故障的实时信息显示于司控台面，弥补了技改缺陷。     

基于灾度辨识的钢闸门巡视检查研究

巡视检查是对钢闸门要点部位开展定期、定点的信息收集,并对警兆信息做出快速辨识和评估的重要内容。应用灾度辨识的警兆信息评估方法,综合钢闸门巡视检查的各类要素信息,明确工程最大隶属的灾度等级(Ⅰ～Ⅴ级),可作为工程日常巡视检查决策的重要软技术手段。     

日本三菱材料公司水泥窑协同处置废物现状及探讨

通过详细分析日本三菱材料公司下属水泥工厂获得的废物处置许可证的种类、处置废物的范围、处置能力、处置业绩、污染物排放以及实际生产过程中的安全措施和社区互动,为国内水泥窑协同处置废物企业提供生产和管理参考.     

Partial safety factors for laminated glass

Glass plies can be bonded together by polymeric interlayers to form laminated glass. Thanks to the capacity in finding alternative stress paths after partial breakage, it is commonly accepted that the more the layers are, the higher the safety level is. However, a negative aspect is that the tensile strength of glass carries a size effect in terms of surface area, which increases with lamination. Here we evaluate these competing factors by calibrating the partial safety factors to be used in semi-probabilistic (level-I) design, through comparison with probabilistic (level-III) methods in paradigmatic case-studies under wind, snow, and dead weight. Starting from a two-parameter Weibull distribution for glass strength, the “failure modes” approach determines the statistical distribution of strength for a multi-laminate as a function of the number of plies, which interferes with the statistics for actions. As a function of the target probability of failure for the assigned class of consequence, we introduce a new coefficient in the verification formula of level-I, to account for the effects of lamination with dependence upon the number of plies. We find that there is strong gain when passing from a monolith to a two-ply laminate, but the advantage fades by increasing the number of layers. Verification formulas of this type could avoid overconservative design.     

Development of an experimental test rig for cogeneration based on a Stirling engine and a biofuel burner

A system consisting of a last-generation Stirling engine (SE) and a fuel burner for distributed power generation has been developed and experimentally investigated. The heat generated by the combustion of two liquid fuels, a standard Diesel fuel and a rapeseed oil, is used as a heat source for the SE, that converts part of the thermal energy into mechanical and then electric energy. The hot head of the SE is kept in direct contact with the flame generated by the burner. The burner operating parameters, designed for Diesel fuel, were changed to make it possible to burn vegetable oils, not suitable for internal combustion engines. The possibility of adopting different configurations of the combustion chamber was taken into account to increase the system efficiency. The preliminary configurations adopted allowed to operate this integrated system, obtaining an electric power up to 4.4 kW_el with a net efficiency of 11.6%.     

山区危险路段公路线形设计安全性分析

山区公路工程设计过程中,必须更加重视安全分项设计,尤其是在危险路段,应妥善调查各种潜在的交通安全风险源,并根据具体的风险源类型制定针对性的安全设计方案。本文以山区危险路段的线形特点为研究背景,选取平曲线半径和横坡率两个指标作为研究对象,定量分析了两种指标对线形安全的影响,并从曲率变化协调性和行车视距合理性角度对山区危险路段安全性进行分析,提出了相应的设计参考及控制措施。     

"人机环管"在煤矿供电安全管理中的应用

制定供电过程中消除安全隐患的针对性措施,可以为矿井安全生产提供必要保障。为探究煤矿供电管理中安全隐患的具体分析方法,首先介绍“人机环管”管理体系的建立过程和核心内容,接着以“人机环管”的管理方法分析了供电管理中的普遍问题。在分析供电管理中的具体问题时,分别得出了“人”“机”“环”“管”4方面的具体措施。分析认为,“人机环管”方法可以有效查找出存在的安全隐患,进而保证煤矿供电系统的安全可靠。     

Research on thermal risk and decomposition behavior of methyl nitrite

The thermal hazards of methyl nitrite(MN) were investigated in the present study. The determination and evaluation of MN decomposition were conducted using a C600 micro thermometer. The thermal runaway reaction characteristics of the compound under different initial pressures were obtained using a VSP2 calorimeter. The kinetic parameters of MN were obtained by regression fitting and calculation of the microthermal experimental data. The experimental and calculated results demonstrated that the potential explosion risk of MN is very high.In addition, there was a high energy barrier in the early stage of the uncontrolled decomposition of MN; however,once the decomposition reaction was initiated, the subsequent decomposition was easily conducted. Under the conditions of adiabatic simulation, the possibility that the reaction was uncontrolled increases with the initial temperature and pressure of the system, and there is a great potential safety risk.