温州“行车灯光语言”处理道路紧急情况

喇叭作为一种"交通语言",大多数驾驶员想通过喇叭声来提醒其他车辆,但结果是造成噪声污染,影响社会环境。近期,温州市交警二大队民警根据《道路交通安全法》灯光使用规定,结合交通管理经验,总结出一套"行车灯光语言",准备先在出租车司机中推广使用。灯语:"你好,注意了"使用方法:亮左转向灯或右转向灯适用:一、车辆停在路边准备起步,亮左转向灯。     

似曾相识的火场悲剧为何一再重演

2013年5月31日13时15分,黑龙江中储粮林甸直属库发生一起火灾事故,造成80个粮囤、揽堆过火和恶劣社会影响,直接经济损失307．9万元。火灾直接原因为粮库作业过程中,皮带式输送机在振动状态下电源导线与配电箱箱体孔洞边缘产生摩擦,导致电源导线绝缘皮破损漏电并打火,引燃可燃物苇栅和麻袋,并蔓延至其他79个粮囤、揽堆货位的苇栅苫盖物。     

挤塑型聚苯乙烯泡沫塑料着火温度实验研究

研究了挤塑型聚苯乙烯(XPS)保温材料两种不同着火方式下的着火温度。采用南京江宁仪器分析厂生产的DW-02型点着温度测定仪对XPS的着火温度进行了测定。利用辐射引燃仪得到了2.2 cm厚挤塑型保温板在不同加热功率下的着火温度。结果表明:DW-02型点着温度测定仪测得的挤塑型聚苯乙烯保温材料的点燃温度约为355℃;热辐射引燃仪测得的2.2 cm厚保温板在不同加热功率下的着火温度是365-370℃,且引燃时间随着辐射引燃仪加热功率的增大而逐渐缩短;明火火源比热流辐射容易引燃挤塑型聚苯乙烯保温板。研究结论对FDS模拟挤塑型聚苯乙烯燃烧特性时,材料热解参数的设定有指引作用,对实际工程中遴选合适的外墙保温材料具有重要的参考价值。     

配制黑火药生产烟花爆竹是否构成犯罪

配制黑火药生产烟花爆竹是否构成犯罪?这关键看烟花爆竹是否刑法意义上的爆炸物,烟花爆竹中的黑火药是否能折算成爆炸物数量予以定罪量刑.     

对一起黑火药燃烧事故发生原因的看法

我局658火药总库内存放的存期已满4年的导火索黑火药粉300kg(据目测,无吸湿、结块现象),按《冶金矿山爆破和炸药生产安全暂行规程》的要求,于1982年8月26日在黑鱼沟尾矿库内的沉积砂上进行销毁时,发生了一起黑火药燃烧事故。是日8时,由总库将300kg 黑火药(成分为硝酸钾75%、硫磺10%、木炭15%)分装10袋,用火药车运至销毁场地。当时,天晴     

拿什么拯救你--我的市场

曾经有这样一个案例:某事主家里被盗,为了防止类似事件的再次发生,他经多方了解,找到了一家出售安全报警器的商店,花300元钱买了一种只有烟盒大小的防盗器.回到家后,他将买来的两只防盗器用双面胶分别贴到了门两侧和阳台旁边,设备安装完毕后,事主将遥控器随身携带.     

海洋球引燃条件分析

为探究海洋球的引燃条件,本文采用实验的方法,选用明火、香烟火和电火花3种点火源,测试在不同距离下海洋球的引燃时间、燃烧持续时间和海洋球表面温度变化情况.研究结果表明:明火可以引燃海洋球,明火条件下海洋球的引燃时间随引燃距离增加而增加,引燃距离超过1.5cm后,海洋球不能被引燃;香烟火无法引燃海洋球,在引燃距离为0和0.5cm时,海洋球仅出现熔化现象,温度最高可达94.7℃,随着距离增加,海洋球熔化所需时间逐渐增加,温度上升速率逐渐降低;电火花(加载电压90V)无法引燃海洋球,电火花仅能在海洋球表面留下烟熏痕迹.本文为降低海洋球引发火灾几率、预防火灾发生提供一些参考.     

金属热颗粒引燃可燃堆积材料的实验研究

电焊操作、烟花燃放、工业磨削和高压电线碰撞等过程容易产生高温热颗粒。这些热颗粒一旦接触可燃材料就有可能引燃材料,导致火灾。该文对热颗粒引燃可燃堆积材料的行为进行实验研究,从而为工业堆积材料的火灾防控方法提供参考。实验加热一系列不同直径(6mm,8mm,10mm,12mm,15mm,20mm)的黄铜金属颗粒作为热源,并采用三种常见的工业堆积材料(木粉,炭粉,羟丙基甲基纤维素HPMC)作为可燃材料的代表物,研究不同功率金属热颗粒对材料的引燃行为,分析金属热颗粒引燃材料的临界功率。结果表明,材料本身的性质会影响热颗粒的引燃行为,HPMC的引燃时间最长,木粉的引燃时间最短。随着热颗粒直径的增加,热颗粒引燃三种材料所需的功率值整体呈增大的趋势。由于燃烧空腔的形成,HPMC的引燃临界功率相对较高。     

防爆开关也会引起爆炸

某企业发生了一起因防爆开关内部放电引燃可燃气体，造成数人伤亡的爆炸事件。　　对该防爆开关现场检查发现，开关内部固定在胶木片之间的一个电触头与连接导线整体脱离固定件，与接地良好的金属外壳接触发生放电。线端放电痕迹清晰，铸铝外壳放电部位被击穿几个直径在８ｍｍ以上的不规则孔洞，安装混凝土墙面上留有熔融金属沫溅落出的占４ｍｍ的印迹。认定该开关即是这起事故的引发点。该防爆开关不防爆的主要原因是：　　（１）由于本开关长时间超负荷运行，致电触头发热，开关的绝缘胶木老化、劣化。因操作、振动或碰撞等多种原因致使触…     

一种磁控防盗报警系统

介绍了霍耳接近开关的构造和特点,利用霍耳接近开关制作了一种磁控防盗报警系统,给出了该系统的原理图和电路简图.通过实验数据分析,该传感防盗器有与众不同的优点.     

Suppression of cone discharges in a powder silo using a grounded metal rod

While filling a large silo with coarse nonconductive powders, strong electrostatic sparks known as a cone discharge, which can become sufficiently energized to ignite a flammable dust cloud, often occur on the surface of a powder heap. In an attempt to mitigate or eliminate a cone discharge, a long metal rod with a pointed tip or a flat tip was vertically installed in the center of an experimental silo (1.5 m in diameter, 2 m in effective height) with the objective that the static charge might be released by the corona discharges or the surface potential of the powder heap reduced by the electric field reducing effect. The experimental results are summarized as follows:(1) No cone discharges were observed while the silo was being filled with polypropylene pellets when either a pointed tip or a flat-tip rod was installed so that its lower end was located 10 cm above or 30 cm below the heap surface level. A corona discharge that occurred on the pointed tip was shown to be effective to some extent in reducing the charge of the powder heap.(2) Brush discharges were observed near the metal rod and its support. However, we assume that the maximum energy was not high enough to ignite a dust cloud with minimum ignition energy greater than 3 mJ.     

Ignitability of aluminous coating powders due to electrostatic spark

Electrostatic Powder coating which is a surface finishing technique has widely been used in paint industry since its invention in the 1960s. However, so far, insufficient attention has been paid to the powder fires and/or explosion hazards caused by electrostatic spark during coating process. This paper is a report of the electrostatic spark ignitability of aluminous coating powders (dry blend-type) used in practical electrostatic powder coating. The Hartman vertical-tube apparatus was used for the minimum ignition energy (MIE) test. Various aluminous coating powders, different with respect to the amount of aluminum pigment, were used in this study. Experimental results obtained in this study are as follows: (1) The aluminous coating powder was so sensitive that even an electrostatic spark with an energy as low as 10 mJ could ignite it. (2) The particle size of aluminous coating powder has a considerable effect on the ignitability when the aluminum pigment concentration is within 6 wt% of the practical coating powder manufacturing standards. Thus, the conventional expression for estimating the MIE can be useful when assessing the electrostatic hazards associated with aluminum coating powders.     

电缆表面粉尘自热行为数学模拟

建立了负载电缆表面粉尘自热过程的稳态传热数学模型,通过数值解讨论其自热行为。     

铝粉尘云燃烧火焰形态分析实验研究

为探索铝粉尘云燃烧火焰形态和灾变演化,基于改造的竖直开口实验管道,借助高速摄像仪和离子探针,研究火焰结构及变化,分析粒径因素对铝粉火焰前锋形态的影响.实验结果表明:铝粉燃烧能量的释放和空间束缚使燃烧转为爆燃,火焰前锋下方存在大片的燃烧反应区;铝粉粒径越小,颗粒氧化层破裂需要的热应力越小,越容易被点燃;随着铝粉粒径减小,...     

不同配比安全点火药B/KNO_3的研究

为研究可靠点燃主装药,性能稳定的B/KNO3点火药,对不同配比的B/KNO3进行配制并对其性能进行测试。不同配比B/KNO3在火焰感度、静电火花感度、撞击感度、摩擦感度4项外界刺激中,除了对撞击非常钝感之外,对其他3项外界刺激敏感。在不同比例的药中,以B/KNO3比例为50:50,粘结剂为X的药火焰感度最高,稳定性好;静电火花感度随B/KNO3中B比例提高而降低,摩擦感度随B/KNO3中B比例提高而提高,但当中B比例从40%提高到50%时,这两感度改变不多。分析得出B/KNO3比例为50:50,粘结剂为X的药满足对主装药点火可靠,稳定性好。     

典型静电放电火花点燃危险性评价方法研究

通过研究典型静电放电火花的实际点燃能力 ,对实际生产工艺工程中的静电放电火花的点燃危险性进行定量评价。静电放电火花的放电相当能量、放电火花空间分布范围和放电火花持续时间 ,决定了静电放电火花实际点燃可燃物的可能性大小 ,因此不同类型的静电放电火花点燃可燃物的差异性很大。根据数据序列理论分析 ,引入静电放电火花点火源序列和可燃物危险性序列之间存在的关联性 ,反映了静电放电火花点燃可燃物的危险程度 ,可用于对静电放电火花的实际点燃危险性进行量化评价。对聚烯烃粉体生产工艺过程中典型和频发性的静电放电火花的点燃危险性进行了定量评价。     

Self-ignition and explosion during discharge of high-pressure hydrogen

The phenomenon of self-ignition and explosion during discharge of high-pressure hydrogen was investigated. To clarify the ignition conditions of high-pressure hydrogen jets, rapid discharge of the high-pressure hydrogen was examined experimentally. A diaphragm was used to allow rapid discharge of the high-pressure hydrogen. The burst pressure was varied from 4 to 30 MPa. The downstream geometry of the diaphragm was a flange and extension pipes, with the pipe length varying from 3 to 300 mm. The diameter of the nozzle was 5 or 10 mm. When short pipes were used, the hydrogen jet did not ignite. However, the hydrogen jet showed an increasing tendency to ignite in the pipe as the length of the pipe became longer. At higher burst pressures, a diffusion jet flame was formed from the pipe. The blast wave from the fireball formed on self-ignition of the hydrogen jet resulted in an extremely rapid pressure rise.     

机械式立体停车库中巷道防火分隔效果研究

使用火灾CFD模拟软件Fire Dynamic Simulator(FDS)建立某机械式立体停车库的火灾动力学模型,研究停车库内巷道的防火分隔作用和巷道顶部的排烟窗对烟气的控制情况。确定了此机械立体停车库的火灾发生概率为0.00786起/年,并调研了车库汽车火灾的热释放速率模型。根据模拟结果,当巷道一侧一辆车着火后,巷道另一侧车辆受到的辐射热流密度为0.6kW/m2~2.0kW/m2,不会引燃巷道另一侧车辆,利用巷道空间作为防火分隔措施是可行的。巷道顶部自然排烟百叶对于控制烟气有着显著作用,在顶层距地面10m高度处,500s时仅起火停车单元及其对面停车单元能见度低于10m,而未开设排烟窗时整个车库能见度均降至10m以下,局部区域在2m以下。     

Study into influence of different types of igniters on the explosion parameters of dispersed nitrocellulose powder

Nitrocellulose is a flammable compound produced by cellulose nitration. The nitrocellulose production and handling are associated with a risk of fire and explosion. Nitrocellulose is used as either collodion cotton (<12.5% N) or as an explosive (>12.5% N). Nitrocellulose is a fibrous or powdered substance and may detonate or burn upon certain conditions. The article compares the combustion parameters of dry nitrocellulose in the KV-150M2-UIBE explosion chamber at the concentrations of 250, 500 and 750 g m⁻³. To ignite a nitrocellulose sample, six different types of igniters were used. A commercially available 5 kJ pyrotechnic igniter was used as the standard. Also used were a nitrocellulose igniter, a pyrotechnic igniter with magnesium powder and KNO₃/KClO₃, and an exploding wire (Kanthal and tungsten wire). The examined igniters were found to affect the explosion parameters of dispersed nitrocellulose. The deviation of the explosion constant K_st reached 50% of the standard value. The highest pressure of 12.73 bar g was reached at a concentration of 750 g m⁻³ and an igniter exploding wire with Kanthal wire. The highest K_st value of 287.9 bar.m.s⁻¹ was achieved at a concentration of 750 g m⁻³, when using the pyrotechnic igniter with KClO₃ and magnesium powder.