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61.
针对江苏省常州市地区村镇自建住宅的抗震性能进行了调查研究,针对存在的问题提出了相应的抗震设防措施与对策. 相似文献
62.
张平 《湖南环境生物职业技术学院学报》2005,11(2):156-160
经济全球化背景下,产业安全问题成为影响中国产业竞争力的重要因素.行业协会对产业具有特殊的安全阀功能.发展中国行业协会,关键取决于政府对其的推动和扶持. 相似文献
63.
O3/GAC/UV预处理医药化工废水的研究 总被引:2,自引:0,他引:2
以对硝基苯甲酸车间废水为试验对象,采用先进的O3/GAC/UV工艺进行预处理。结果表明:对原水CODcr浓度为10960mg/L,经预氧化处理后,CODcr去除率达53%,废水BOD5/CODcr由原来的0.1提高到0.34,极大地改善了废水的生化性能,为后续的生物降解打下了良好的基础。 相似文献
64.
针对阻燃电缆等难燃材料,为研究其在外界热源条件下的火灾性能与蔓延燃烧特性,研制了基于环形加热的阻燃电缆细观燃烧特性诊断实验平台。该平台主要包括三个部分,即:半封闭环形桶式加热与燃烧腔室、样品竖直固定模块和数据采集系统。实验参数的标定及典型阻燃电缆受热与燃烧实验结果表明,常规条件下无法点燃的阻燃电缆,当置于实验平台的加热炉内被加热一段时间后,底部小火源可将其点燃并呈现猛烈的燃烧与蔓延过程。该加热模块能够详细、准确地研究各种阻燃电缆在环形加热条件下的膨胀、引燃及蔓延燃烧的细观特性,而不同的加热模式有助于深入研究阻燃材料在各种热环境下的火灾特性,为阻燃材料的引燃机理及火蔓延模型研究提供了必要的研究平台。 相似文献
65.
66.
Nearly 130 years ago Holtzwart and von Meyer (1891) demonstrated by experiments that explosible dust clouds could be ignited by inductive electric sparks. Then more than half a century passed before the publication of the important quantitative research of Boyle and Llewellyn (1950) and Line et al. (1959). They worked with capacitive electric sparks and found that the minimum capacitor energies ½CU2 required for ignition of various dust clouds in air decreased substantially when a large series resistance, in the range 104–107 Ω, was introduced in the discharge circuit. When considering that the net energies of the sparks themselves were only of the order of 10% of the ½CU2 discharged, the minimum net spark energies required for ignition with a large series resistance were only a few per cent of the net energies required without such a resistance.Line et al. observed that the essential effect of increasing the series resistance, and hence increasing the discharge time of the sparks, was to reduce the disturbance of the dust cloud by the blast wave from the spark. This phenomenon was explored further by Eckhoff (1970, 2017), and subsequently by some simple experiments by Eckhoff and Enstad (1976). Franke (1974, 1977) and Laar (1980) confirmed the additional finding of Line et al. (1959) that the minimum ½CU2 for ignition is also substantially reduced by including a series inductance in the discharge circuit, rather than a series resistance. The basic reason is the same as with a large series resistance, viz. increased spark discharge time and hence decreased disturbance of the dust cloud by blast wave from the spark. For this reason inclusion of an appreciable series inductance in the spark discharge circuit is an essential element in current standard MIE test methods.In experiments with spark ignition of transient dust clouds produced by a blast of air in a closed vessel, it is necessary to synchronize the occurrence of the spark with the formation of the dust cloud. The precision required from this type of synchronization is typically of the order of 10 ms, which can be obtained even by mechanical arrangements, such as rapid change of spark gap length, or of the distance between two capacitor plates. The present paper reviews some methods that have been/are being used for achieving adequate synchronization of dust cloud appearance and spark discharge. Some current standard experimental methods for determining MIEs of dust clouds experimentally have also been reviewed. The same applies to some theories of electric-spark ignition of dust clouds.At the end of paper some suggestions for possible future modifications of current standard methods for measuring MIEs of explosible dust clouds are presented. With regard to justifying significant modifications of existing standard methods, the “bottom line” is, as quite often in many connections, that any modifications should be based on realistic cost/benefit evaluations. 相似文献
67.
68.
为评估机场旅客安检系统的保障能力,并针对评估过程中存在的不确定性和指标中影响因素之间的不独立性,采用模糊网络分析法(Fuzzy-ANP)建立系统评估模型。在综合考虑安检影响因素的前提下,从人、机、环、管四方面建立了机场旅客安检系统保障能力评估指标体系。以某机场为例,应用模型进行实证分析得出结论,影响该机场旅客安检系统保障能力的主要因素为员工工作量、员工心理状况和设备完好率。研究表明,评价结果与该机场实际运营状况相符合,该方法能更好地满足机场运营安全管理的实际要求。 相似文献
69.
The prevention of dust explosions is still a challenge for the process industry. Ignition, in particular, is a phenomenon that is still not completely understood. As a consequence, safety conditions pertaining to ignition suppression are rarely identified to an adequate level. It is well known that, in general, the ignition attitude of a dust depends on several factors, such as the nature of the chemical, the particle size, moisture content, etc., but there is still a lack of knowledge on the effect of the single variables.This paper has the aim of providing data on the Minimum Ignition Temperatures of dust mixtures obtained from a mixing of a combustible dust (flour, lactose, sucrose, sulphur) and an inert dust (limestone, extinguishing powders) as well as from the mixing of two different combustible dusts. Various mixtures with different weight ratios have been tested in a Godbert Greenwald (GG) furnace and on a hot plate in order to measure the effect of mixture composition on the Minimum Ignition Temperature (MITL) of the layer and on the Minimum Ignition Temperature (MITC) of the cloud. In order to further verify the effects of inert dust particle size, inerts sieved to different size ranges have been tested separately. Generally, both MITL and MITC increase as the inert content is increased. MITC is poorly affected by inert particle size when limestone is used. The MITL of pure flour is higher than the MITL of mixtures containing up to 40% of 32–75 μm of limestone. This was probably due to the behaviour of pure flour during the test, which demonstrated strong tendency to produce char, cracks in the layer and detachment from the hot plate. 相似文献
70.
To restrict the progress of the global warming, A2L refrigerants such as 2,3,3,3-tetrafluoroprop-1-ene (R1234yf), (Z/E)-1,3,3,3-tetrafluoroprop-1-ene (R1234ze), and difluoromethane (R32) have been expected of alternatives to the standard refrigerants currently in use. The ignition hazard of A2L refrigerants under plausible accident situations in service and maintenance was examined experimentally for two cases: leakage of an A2L refrigerant from a pinhole in a pipe or hose (Scenario 1), and leakage of an A2L refrigerant into an item of equipment used for service and maintenance, such as a collection device (Scenario 2). In Scenario 1, the location of the flammable zone and the possibility of a jet flame being formed instantaneously on contact with an ignition source were examined. Even when R1234yf leaked from a 4 mmϕ pinhole (corresponding to breakage of a pipe), the flammable zone extended only about 10 cm from the pinhole in the downstream region. In an ignition test with a continuous spark as the ignition source, a pale emission appeared only near the spark, and the flame did not propagate to the rest of the refrigerant jet. In Scenario 2, the accumulation and ignition behaviors of A2L refrigerants in a model collection device were examined experimentally. Ignition and flame propagation occurred in a test on a model collection device lacking slits, whereas when slits wider than 20 mm were present, ignition and flame propagation did not occur. Even if R1234yf leaked into the model collection device, provided that slits of an effective width were present, the R1234yf could diffuse through slits and barely accumulated, and no ignition or flame propagation occurred. 相似文献