气瓶充装前检查的重要作用

介绍了因气瓶充装前不检查而发生的爆炸及质量事故，以及气瓶充瓶前严格按照《气瓶安全监察规程》检查，使气瓶的不安全隐患得以排除的几个例子，比较了气瓶充装前不检查以致造成不安全的惨痛结果，以及气瓶充装前检查了安全的良好结果，从而有力的证明了气瓶充装前检查所起的重要作用。     

焊接绝热气瓶充装系数取值探讨

指出了在法规标准中明确焊接绝热气瓶充装系数的必要性,并提出了充装系数的确定方法.     

氢气气瓶充装的技术及安全

氢气是主要的工业原料,也是最重要的工业气体和特种气体,但是氢气也是易燃易爆的气体,容易引发事故。综述了氢气气瓶充装过程中的操作流程和氢气充装过程中的危险性分析。最后,对氢气充瓶过程中易出现的事故及原因、出现事故后的处置技术、出现事故前的预防措施等三方面加以阐述。     

气瓶充装,储运和使用中的安全与参数

论述了气瓶的充装，储运和使用中的安全问题和注意事项，并列出５８种常用气体的物理状态，生物学性质，在空气中的燃烧范围和允许极限浓度，充装系数和气瓶颜色标记等。     

音响检查在气瓶检验中的应用

介绍了音响检查的实例,并结合内部检查、重量及壁厚测定等综合评定结果,说明了音响检查的实用性和准确性。     

气瓶安全与检验问答(二十六)

问:气瓶整体或局部被火烧过,怎样对其进行检验评定?答:气瓶整体或局部被火烧的情况,大致可分为4种:(1)漆膜烧焦或烧毁;(2 )金属烧结;(3)气瓶变形;(4 )瓶阀件熔化。在受检瓶上发现上述(2 )、(3)情况时,应把受检瓶评定为报废。如果受检瓶的漆膜仅被烧焦或鼓包而未脱落,则说明未伤及金属,应评定为合格。在受检瓶漆膜被烧脱落或瓶阀件被烧熔化的情况下,如果条件不允许把被烧的受检瓶送气瓶制造厂按原工艺重新进行热处理和试验,则该瓶应评定为报废。在气瓶定期检验中,还会遇到另外两种局部热损伤:(1)在气瓶上进行电焊引弧导致瓶体出现“弧疤”;(2…     

液化气体气瓶爆炸事故分析的相关计算

通过对一起液氨气瓶爆炸事故的分析,探讨液化气体气瓶事故分析的相关计算问题。     

新形势下气瓶安全管理的现状分析与应对措施

气瓶在各行业中大量应用,但随之而来的气瓶事故也越来越多,不少事故造成严重后果.结合实际气瓶安全管理工作的经验,具体分析了气瓶充装、运输、检验、使用等环节存在的问题,总结经验教训,提出加强各环节气瓶安全管理的措施.     

气瓶安全与检验问答(二十五)

问:乙炔管道的水压试验压力和气密性试验压力是怎样规定的,试验时应注意什么?答:管道水压试验压力为:1 管道工作压力小于0 7MPa时,水压试验压力为2 2MPa ;2 管道工作压力在0 7～0 15MPa时,水压试验压力为3 2MPa ;3 压缩机后的高压管道,水压试验压力为管道工作压力的2倍。在试验过程中,先升压至水压试验压力,保压10min ,然后将压力降至气密性试验压力,进行外观检查,如无破裂、变形、渗水和降压现象,则认为水压试验合格。水压试验合格后,再以气压进行气密性试验。气密性试验压力为工作压力的1 2 5倍。试验时升压至气密性试验压力后,…     

浅谈永久气体钢瓶在充装前检查发挥的重要安全作用

永久气体钢瓶在充装过程中若有误用报废瓶、错装、气瓶超期服役、混装等情况对钢瓶充装及使用过程产生严重的安全隐患,充装前检查主要目的就是发现并排除这些安全隐患、防止事故的发生,在气瓶安全使用中发挥重大的作用。     

关于氧气钢瓶充装中的安全问题

介绍了氧气充灌站的防火间距问题 ,防爆墙结构设计问题和充灌站管道流速强度校核问题 ,以及充装工艺的安全问题。     

浅谈大型制氧企业液氧充装过程的安全管理

介绍武钢氧气公司对液氧充装过程的安全管理,以及现场充装设备的改造,通过建立健全安全管理制度,改进充装设备的安全性能,全面提高了液氧充装过程的安全性,为大型制氧企业加强液氧充装安全提供借鉴。     

Experimental study of FRP tube encased concrete cylinders exposed to fire

In recent years, fiber-reinforced polymer (FRP) tube encased concrete cylinders have been widely studied for their use in civil infrastructure. However, the performance of these FRP/concrete systems exposed to fire is a serious concern due to the combustibility of FRPs. This paper presents test results of temperature distributions and residual strength of three groups of FRP tube encased concrete cylinders (Groups 1, 2, and 3) exposed to a jet fire of 982 °C for a time period of 4 min, 8 min, and 12 min, respectively. The temperature distribution of the confined concrete cylinders under fire was recorded by the embedded thermocouples. After fire test, uniaxial compression tests were conducted to evaluate the residual strength. The results were compared with that from a group of FRP tube encased concrete cylinders without fire exposure (Group 4). To improve the fire resistance of the confined concrete cylinders, a fireproof additive was also applied to three other groups of specimens (Groups 5, 6, and 7) and these specimens were also fire tested for 4 min, 8 min, and 12 min, respectively. SEM was used to examine the burn-out of resin by fire. The test results show that the fire exposure has a significant effect on reducing the residual strength of the confined concrete cylinders. The resin has been fully burned-out and carbonized after 8 min of fire exposure. After 12 min of burning, the FRP tube basically loses its capacity to provide any meaningful confinement. The fireproof additive used is effective in minimizing the effect of the fire hazard.     

The examination of heat effects on bond degradation in reinforced concrete using acoustic emission

Experimental tests were carried out on pull-out concrete speciments with 8 mm dia. tor steel bars to examine the extent of deterioration of bond at the interface of steel and concrete afer exposure of the speciments up to 800°C furnace temperature. The bond stress-slip behaviour was examined and acoustic emission monitored simiultaneously. The bond stress-emission and slip-emission were compared and correlated with the bond stress-slip behaviour for speciments subjected to diferent levels of temperature both in the heated as well as the residual conditions. Random samples of waveforms of the emission for specific levels of temperature were compared with respect to the amplitude and time period of the pulses as well as the occurrence of reflections etc. Consequently attempts were made to utilise acoustic emission behaviour in establishing the trend of bond degradation in reinforced concrete by heat effects. The control of variable was the level of temperature exposure.     

A finite difference approach to acoustic tomography in anisotropic media

In this paper, a finite difference formulation for acoustic wave propagation is used as the basis for tomographic reconstruction. This approach offers some interesting advantages over traditional, ray based methods; particularly for anisotropic media. Since this approach provides information on the full acoustic field (not individual rays), it offers a conventional way to incorporate beam skew and ray bending phenomena directly into the problem formulation. Here, we present a tomographic reconstruction algorithm which is adapted from the algebraic reconstruction technique (ART) to take full advantage of the finite difference formulation of the problem. Results are presented to illustrate the utility of this approach.     

Analysis of thermal stress intensity factors for cracked cylinders using weight function method

In this paper a general weight function was derived to evaluate the thermal stress intensity factors of a circumferential crack in cylinders. The weight function derived is valid for a wide range of thin- to thick-walled cylinders and relative crack depth. Closed-form stress intensity factor based on the weight function method was derived as a function of the Biot number and relative depth and various inner-to-outer radius ratios of cylinders. The accuracy of the analysis has been examined using the finite element method results and were compared to existing solutions for uniform loading in the literature for special geometries, indicating an excellent agreement.     

LNG大型低温储罐膨胀珍珠岩填充技术

以国内某一LNG大型低温储罐为例,阐述了膨胀珍珠岩的填充装置、主要性能、填充方法及过程控制等内容,同时提出天气、安全因素对珍珠岩填充的影响及应对措施。     

An acoustic tensile load cell able to operate under high water pressures

The principles of operation and the experimental equipment used during an investigation into the role of percolating water within concrete and rock, have been outlined. Attention has been drawn to a problem of measuring a friction force which, if not resolved, would have compromised the investigation. The design requirements of a simple acoustic tensile load cell, capable of resolving the problem, are listed with details of its design, construction and satisfactory performance.     

Fullerene-incorporation for enhancing the electron beam resist performance for contact hole patterning and filling

The fullerene molecules such as C60 and C70 were incorporated in the commercial positive electron beam resist to investigate the performances for patterning and filling the contact holes at nanometer scale. The sensitivity, process window and contrast of the modified resist were improved, while the toluene dilution degraded the sensitivity. The electron beam dose affected the designed holes dimension, and the adulterated resist could print sub-50 nm holes pattern. We found the small amount (0.01–0.02% w/v) of fullerene molecules very effectively promoted the etch resistance and selectivity under fluoro-containing gases, and minimized the film stress. The etching resistance for C60 and C70 modification could be improved by 65% and 68%, respectively. Together with the fullerene-incorporated resist and the etching processes, the sub-50 nm contact hole could be achieved. In addition, the gap-filling and step coverage capability of titanium nitride into nanometer contact hole with chemical vapor deposition was better than physical vapor deposition.     

Circumferential stiffness tailoring of general cross section cylinders for maximum buckling load with strength constraints

Stiffness tailoring of laminated composite structures using steered fibre tows is a design method that maximally uses the directional properties of composite materials. Cylindrical structures usually have circular cross sections while some application, geometric or aerodynamic requirements can necessitate other cross sections, e.g. elliptical. Circumferential tailoring can increase the buckling load of thin cylinders by compensating for non-uniform sectional loading such as bending and/or varying radius of curvature in general cylinders. Here, strength constraints are considered in maximum buckling load design, to ensure that the failure load is greater than the buckling load. A two-step optimisation framework is used to separate the theoretical and manufacturing issues in design. A computationally cheap semi-analytical finite difference method is used to solve the linear static and buckling problems. Conservative failure envelopes based on Tsai-Wu failure criterion are used for strength evaluation. To avoid repetitive analyses, successive convex approximation method is used. For demonstration, circumferential tailoring framework is applied to a circular cylinder under bending and an elliptical cylinder under axial compression. The improvements in buckling capacity of variable over constant stiffness designs are shown and verified using nonlinear buckling analysis in the commercial FEM software Abaqus^TM, and the mechanisms of improvements are investigated.