利用SEM-EDS分析火场中白炽灯灯丝通电状态

该文模拟火灾现场中白炽灯破坏的不同情况,制备普通白炽灯在不同状态下破坏的灯丝残骸试样,利用扫描电子显微镜-X射线能谱仪分析灯丝残骸表面的微观形貌及其元素组成含量.研究发现,通电状态下被破坏的白炽灯灯丝表面与未通电破坏状态下灯丝表面的元素成分差异较大.经过高温或烟熏的作用,灯丝表面成分也有变化.鉴于不同破坏条件下灯丝表面成分及含量存在明显的差异,可以利用能谱分析的方法判断火场中白炽灯的通电状态.     

火场中电熨斗残留物的形貌特征分析

本文模拟电熨斗正常使用、通电过热使用、直接受火灾作用、正常使用后受火灾作用、通电过热后受火灾作用,获得电熨斗在不同条件下的试验样品,利用扫描电镜观察电热丝的微观形貌特征,并进行对比分析.为公安消防机构认定火灾原因和明确火灾责任提供了一种新的鉴定依据和方法.     

“热得快”火灾痕迹试验研究

对处于4种不同状态下的"热得快"从宏观形貌和微观形貌进行比较、观察和分析;同时系统地分析了"热得快"金属管表面形貌特征和电热丝表面形貌特征形成的机理和主要影响因素。结果表明:不同状态下"热得快"金属管宏观形貌特征存在差异,但容易受到火场复杂条件的影响,不能对火灾前"热得快"所处的状态进行定性;通过扫描电子显微镜(SEM)分析技术观察"热得快"电热丝的微观形貌的差异,可以直观快捷地识别"热得快"在火灾前所处的状态,为"热得快"火灾残留物的鉴定提供一种新的鉴定依据和技术方法。     

电气火灾残留物的SEM分析方法研究

通过分析电气火灾的形成原因,总结出该类型火灾的残留物种类。然后利用电焊机和电阻炉等设备分别制备出铜铝导线的一、二次短路熔痕和火烧熔痕,电热丝的通电过热和火烧熔痕,并运用了目前一种新式有效的显微结构分析工具——扫描电子显微镜,对以上样品的表面进行微观形貌的观察、比较与分析。通过分析讨论,可以发现电气火灾残留物在火灾前后其表面的微观形貌特征存在明显不同。根据这些特征能够很轻易的鉴别出电气设备在火灾发生前的使用状态,从而推断出火灾是否由该电气设备引发而起。此项结论能够为从事火灾调查的人员对电气火灾原因的准确认定提供可靠依据,也能够为扫描电子显微镜技术的应用领域进行拓宽提供一些帮助。     

用事故残骸件形貌特征分析判断电气事故

在电气事故的分析中,常常会遇到一些难以定论的问题。例如,现场存在几种火源,怎样判断事故的性质,确定直接原因?电气短路可以引起失火,失火也能引起电气短路,怎样确定它们之间的因果关系? 我们根据大量的模拟试验及电气事故分析的实践,总结出用事故残骸件的形貌特征分析、判断电气事故的方法。实践证明,它对正确判断事故(故障)性质,准确地确定事故(故障)直接原因,是可靠的。本文重点介绍电气事故(故障)残骸件上的形貌特征。 一、导线过负荷 不同种类、不同规格的导线都有其规定的安全电流。当导线过负荷,通过的电流大于安全电流时,就可能使…     

手持砂轮打磨金属粉尘微观特征研究

粉尘微观特征对职业健康危害及粉尘的宏观运动存在一定影响。以轨道交通工具生产企业手持砂轮打磨产生的碳钢、不锈钢、铝粉尘为研究对象,利用激光粒度仪、电子显微镜(SEM)对粉尘颗粒大小、颗粒分布特征及形貌特征进行分析,初步探讨了打磨对象的材料和打磨工艺对粉尘颗粒及微观形貌的影响、打磨产生的沉降性粉尘与空气中粉尘粒度及形貌的区别。结果表明,手持砂轮打磨的金属粉尘颗粒以粗颗粒为主;金属材料物理机械性能是影响粉尘颗粒及形貌的主要因素;同一打磨岗位上产生的沉降性粉尘与空气中漂浮粉尘的形貌特征一致,只在颗粒尺度上有差别。     

典型固体可燃物燃烧沉积物微观形貌特征的研究

利用火灾现场中燃烧物沉积物所特有的火灾原始信息,可以帮助火灾调查人员准确辨识与鉴别起火部位或起火点附近可燃物分部情况,辅助判断初始起火材料和起火部位的特点,通过燃烧模拟试验,开展了木材、化纤织物、棉织物、PVC制品、聚氨酯泡沫等常见固体可燃物燃烧沉积物微观形貌特征研究。首先,利用SEM 分析了不同材料沉积物中粒子分布、微观形貌等结构性差异。接着,进行了颗粒物的形貌学测量和组成成分测定。最终,得到了样本的量化差异特征。研究结果表明:5种固体可燃材料燃烧沉积物存在结构性差异,但并不显著;对组成粒子进行的形貌学测量和成分测定,可以量化区分材料属性。该方法可以为建立火灾现场起火部位可燃材料的燃烧时序性提供技术支持。     

循环载荷下煤裂隙演化试验研究

为了研究循环载荷下的煤体裂隙演化特征，在不同应力水平和不同频率条件下分别进行煤样破坏力学及声发射试验。结果表明:应力-应变曲线呈疏-密-疏的变化特征，对应的振铃数柱状图呈U型；上限应力点的应变值、累积能量、撞击计数均随循环次数增加而上升，曲线呈倒S型；煤裂隙演化经历了原始裂隙闭合、新生裂隙稳定发育和裂纹贯穿破坏等3个不同阶段；循环载荷的应力水平和加载频率对煤体疲劳寿命的影响具有差异性，对煤体裂隙演化和破坏模式均有明显影响。     

动载下巷道围岩微震响应特征及支护研究

为探讨动载下深部巷道围岩变形特征，采用微震监测系统、顶板动态监测仪及FLAC3D 数值模拟软件研究深部工作面回采中微震活动特征及巷道变形破坏特征，模拟动载前后巷道围岩及支护体力学响应特性。研究结果表明:微震事件分布与累计损失能量均呈现出明显的3阶段特征，与工作面开采过程出现的初次来压、采空区初次见方和遇见断层现象相对应；微震事件的分布在时间和空间上具有一致性；动载下顶板破坏程度大于底板及两帮；动载扩大了巷道围岩塑性区范围，改变了围岩的受力状态，增大了围岩的变形量与支护体的受力；通过增加锚杆直径、长度、排距及提高预紧力对支护结构进行优化，现场监测数据表明，优化后支护方案保证了围岩的完整性，限制了围岩的变形，减小了锚杆受力，能够有效控制采动影响下巷道围岩的变形，对采动影响下深部巷道维护保证煤矿安全生产具有参考应用价值。     

机械加工表面粗糙度对4130 X钢在0.5%NaCl溶液中的腐蚀性能影响

本文采用动电位极化、电化学阻抗谱、微观形貌观测等方法研究了不同表面粗糙度的4130X钢在质量分数为0.5%NaCl溶液中的腐蚀行为。实验结果表明,随表面粗糙度下降,试样表面积变化不大,其自然腐蚀电位下降,然腐蚀电流密度降低,电荷转移电阻降低,腐蚀反应剧烈程度整体有所下降。微观形貌显示,在反应发生初期,试样表面首先于凸起位置发生腐蚀,并且随腐蚀反应的进行逐渐扩展至试样整体表面。表面粗糙度对腐蚀反应影响主要来源于试样表面的几何形状差异、电化学活性差异和表面状态差异。     

一种解决线型光束感烟火灾探测器环境光干扰问题的方法

针对常规的线型光束感烟火灾探测器抗环境光干扰能力较差,在白炽灯、氙灯以及太阳光等干扰下易误报或丧失火灾探测能力的问题,采取了一系列软硬件有效技术改进措施,经实验和示范工程验证,克服了环境光干扰对线型光束感烟火灾探测器的影响.     

Visual performance for trip hazard detection when using incandescent and led miner cap lamps

Introduction

Accident data for 2003-2007 indicate that slip, trip, and falls (STFs) are the second leading accident class (17.8%, n = 2,441) of lost-time injuries in underground mining. Proper lighting plays a critical role in enabling miners to detect STF hazards in this environment. Often, the only lighting available to the miner is from a cap lamp worn on the miner's helmet. The focus of this research was to determine if the spectral content of light from light-emitting diode (LED) cap lamps enabled visual performance improvements for the detection of tripping hazards as compared to incandescent cap lamps that are traditionally used in underground mining. A secondary objective was to determine the effects of aging on visual performance.

Method

The visual performance of 30 subjects was quantified by measuring each subject's speed and accuracy in detecting objects positioned on the floor both in the near field, at 1.83 meters, and far field, at 3.66 meters. Near field objects were positioned at 0 degrees and ± 20 degrees off axis, while far field objects were positioned at 0 degrees and ± 10 degrees off axis. Three age groups were designated: group A consisted of subjects 18 to 25 years old, group B consisted of subjects 40 to 50 years old, and group C consisted of subjects 51 years and older.

Results

Results of the visual performance comparison for a commercially available LED, a prototype LED, and an incandescent cap lamp indicate that the location of objects on the floor, the type of cap lamp used, and subject age all had significant influences on the time required to identify potential trip hazards. The LED-based cap lamps enabled detection times that were an average of 0.96 seconds faster compared to the incandescent cap lamp. Use of the LED cap lamps resulted in average detection times that were about 13.6% faster than those recorded for the incandescent cap lamp. The visual performance differences between the commercially available LED and prototype LED cap lamp were not statistically significant.

Impact on Industry

It can be inferred from this data that the spectral content from LED-based cap lamps could enable significant visual performance improvements for miners in the detection of trip hazards.     

农电网改造中应注意的问题

结合农电网改造工作实践及特点,阐述了过去农电网中出现的问题,提出了在改造过程中应注意的问题及对策措施.     

The potential impact of light emitting diode lighting on reducing mining injuries during operation and maintenance of lighting systems

Research by the US National Institute for Occupational Safety and Health (NIOSH) indicates that light emitting diodes (LEDs) can be used to enhance safety by improving a miner’s ability to see mining hazards and reducing glare. This paper investigates if LEDs provide another benefit by reducing miner exposure to hazards during maintenance and operation of LED lighting. LEDs could provide useful lives up to 50 times longer than incandescent lighting commonly used in mining and could enable design changes to reduce certain hazards. The mining accident records compiled by the Mine Safety and Health Administration (MSHA) were examined to determine the extent and nature of accidents involving the maintenance and operation of mine luminaries. A total of 140 relevant accident records were found for the years 2002–2006. These incidents resulted in 3668 days lost from work with an additional 925 days of restricted activity. The injury narratives were studied to determine if the implementation of LED-based luminaries could reduce injury severity and frequency. The greatest near-term potential impacts appear to be related to reducing maintenance and cap lamp redesign. Longer term (5 years), low-power and lightweight auxiliary LED lighting for surface mines could also have potential impact for improving safety.     

配电线路发生火灾事故的原因及预防

介绍了配电线路在运行中发生短路、过负荷以及导线或电缆接头处接触电阻过大而引起导线过热、产生火花和电弧引起火灾事故的原因。并针对上述原因 ,提出安全用电 ,预防配电线路发生火灾事故的安全技术措施     

微污染水源水中磷的去除

微量和限量的有毒有害有机污染物和城市污水中的氮磷进入水体，使饮用水水源受到轻度污染，这不仅威肋了人类的健康，也对传统净水工艺提出挑战。研究了电凝聚法对微污染水中磷的去除效果，并探讨了电流密度、电解时间、pH值等主要因素对除磷效果的影响。     

柴油环卫车电动化替代环境效益分析及可行性评估

以环卫车为研究对象,通过使用阶段柴油环卫车和电动环卫车污染排放强度对比,分析电动化替代所产生的环境效益。应用模糊数学模型方法从技术、经济、配套设施、污染减排效益方面,综合评估环卫车电动化替代可行性。结果表明:电动环卫车较柴油环卫车具有显著的减排效果,主要大气污染物排放可减少95.5%。影响柴油环卫车电动化替代的关键因素在电池动力性能、续航能力、经济成本和配套设施充电时长等方面。模糊数学模型的评估结果表明,50%柴油环卫车进行电动化替代是最佳方案,能较好地平衡经济性和大气环境保护的公共利益。未来提高电动化替代比例,还需依靠科技创新改进电动环卫车电池技术和动力等性能,降低购置成本,加强充电桩等配套基础设施的完善。     

尾矿库溃坝泥石流相似模拟试验台设计及验证

泥石流是一种极具破坏力的地质灾害类型,而尾矿库溃坝形成的泥石流除产生巨大破坏力外,还会造成严重的环境污染问题,为了分析其流态演进过程设计了泥石流相似模型试验台。本尾矿库溃坝泥石流相似模拟试验台采用全透明技术以观察泥石流的流态演进过程,同时在传感器对应位置外侧固定量尺,以记录泥石流流动过程中泥深的动（泥石流淹没高程）静（泥石流结束后滞留泥浆高度）态变化。与现有技术相比具有5大优点,主要体现在弯度调节、坡度调节及闸门装置3大系统,并通过相似模型试验与前人研究成果对比,验证了此试验台的可行性,对完善矿山泥石流流体力学理论及矿山泥石流防灾减灾工作具有重要的科学价值及意义。     

Evaluating the blue-light hazard from solid state lighting

Purpose. New light sources including light-emitting diodes (LEDs) have elicited questions about retinal damage, including the blue-light hazard. Some organizations have recommended avoiding using LEDs with correlated color temperatures exceeding 3000?K, since they tend to produce greater short-wavelength energy. This article provides quantitative comparisons among light sources and use cases as they affect the blue-light hazard. Methods. The spectral radiant power characteristics of incandescent, fluorescent, LED and daylight sources were evaluated in terms of blue-light hazard using standard procedures for phakic, aphakic and pseudophakic eyes. Results. Under most use cases, LEDs do not exhibit greater risk for the blue-light hazard than other sources (e.g., incandescent). Because they generally produce little to no ultraviolet energy, LEDs often present less risk to aphakic eyes. Conclusions. LEDs present no special concerns for the blue-light hazard over some other common sources in typical use cases because photophobic responses limit exposure to bright sources. Where photophobic responses might not occur (e.g., eye surgery patients or premature infants) or where individuals suppress these responses (e.g., stage actors), caution is necessary. Evidence remains inconsistent regarding the risk of human retinal damage from long-term exposures to light insufficient to reach acute blue-light hazard thresholds.