靶式流量计在火灾烟气流速测量中的应用

分析了几种传统气体流速测量仪器的原理及其应用于火灾烟气测速时的缺陷,介绍了靶式流量计的工作原理及应用靶式流量计测量火灾烟气流速的方法.利用三种不同的仪器,对水啧淋作用下自然排烟口的烟气流动速度进行了试测.实验结果证明,在处理低速、中温、高湿度和多颗粒杂质火灾烟气的测速问题上,与传统方法相比,靶式流量计具有更好的适用性和明显的优越性.     

国内外数字化应急预案技术发展现状与趋势

简述了数字化预案的概念、功能和主要开发步骤;分析了数字化预案发展的三个阶段,即电子化、可视化和智能化;通过国内外数字化预案项目典型案例,分析了国内外数字化预案技术的发展现状与趋势,以期为我国数字化预案技术发展做出有益的探讨。     

Hazard evaluation of hydrogen–air deflagration with flame propagation velocity measurement by image velocimetry using brightness subtraction

Deflagration phenomena in hydrogen–air mixtures initially filled in 1.4 m³ spherical latex balloons were measured using a high-speed digital video camera and pressure transducers. The image velocimetry using brightness subtraction was introduced to eliminate the background effects for obtaining accurate time evolution records of flame propagation velocity. The maximum flame propagation velocity of about 100 m/s was observed with maximum overpressure 15 kPa at 1 m from ignition point. According to the detailed flame propagation velocity records, there were long deceleration durations. The observed maximum overpressure was smaller than the overpressure estimated by the basis of the observed maximum flame propagation velocity and the pressure wave theories of spherical flames. A new blast curve plot of scaled overpressure vs. distance was tentatively proposed.     

Gender differences in the perception of organizational influence tactics

A short incident describing a political influence attempt was given to 152 management level and professional employees. Subjects were then asked to complete short attitude scales pertaining to the characteristics of the actor and the incident. The experimental factorial design included three factors (1) sex of subject, (2) sex of influencing party, (3) sex of target of influence. The results suggest that males are more tolerant of political behavior than women. Subjects view political manipulators of their own sex more favorably than manipulators of the opposite sex. Subjects of both sexes are more tolerant of political behavior when the victim of the behavior is a member of the opposite sex rather than of their own sex. The results may suggest a growing inclination on the part of both genders to identify with members of their own sex as a meaningful coalition and react to organizational events in view of the implications to members of their own gender. Possible implications for research and intervention are suggested.     

Hospitalizations for immersion-related injuries in Alaska 1991–2000

ObjectiveThis study analyzed factors associated with injuries to hospitalized victims of nonfatal immersion-related events in Alaska from 1991 through 2000.DataAlaska Trauma Registry (ATR) records of victims of nonfatal immersion events requiring hospitalization were examined to identify factors associated with injury outcomes. Subjects were divided into two groups: the “immersion only” (IO) group had no additional injuries associated with their immersion-related events, while subjects in the “associated injury” (AI) group incurred additional trauma during injury events.ResultsThere were 176 ATR records of nonfatal immersion events. In 87 (49.5%) cases, hospitalizations were due to the effects of immersion only (IO group). In 89 (50.5%) cases, hospitalizations were due not only to the effects of immersion, but also due to additional injuries occurring immediately before or while immersion took place (AI group). The final logistic regression model revealed statistically significant relationships between age greater than 12 years, female gender, white ethnicity, and operation of water transport vehicles, and increased risk for associated injury outcomes (p < 0.05).DiscussionThis study is the first of its kind to analyze factors associated with the most severe nonfatal immersion-related injuries in Alaska, and identifies target populations for future safety campaigns.     

磨料特性对磨料气体射流破煤影响的实验研究

针对磨料气体射流,基于气固两相流理论分析影响磨料速度的因素,在一定喷嘴结构基础上,通过实验研究磨料特性对破煤效果的影响。通过理论分析发现,影响磨料速度的主要因素有磨料密度和磨料粒径。实验结果表明:在射流压力一定条件下,石英砂、石榴石和棕刚玉3种磨料中棕刚玉破煤深度最大,在80,120,200和280目4种不同目数磨料中,120目磨料破煤效果最优。通过分析磨料特性的影响,得出磨料硬度对破煤的影响最大,其次是磨料密度。开展磨料气体射流破煤实验,确定了磨料气体射流中最优射流靶距为70 mm,最佳破煤磨料为120目的棕刚玉磨料。     

Experimental study of the effect of nitrogen addition on gas explosion

Flame propagation and combustion characteristics of methane/air mixed gas in gas explosion were studied in a constant volume combustion bomb. Stretched flame propagation velocity, unstretched laminar flame propagation velocity, unstretched laminar combustion velocity and Markstein length were obtained at various ratios of nitrogen to gas mixture. Combustion stability at various ratios of nitrogen to gas mixture was analyzed by analyzing the pictures of flame propagation. Furthermore, the effect of initial pressure on the flame propagation and combustion characteristics of methane/air mixed gas in gas explosion was analyzed. The results show that the unstretched laminar flame propagation velocity, the unstretched laminar combustion velocity, Markstein length, flame stability, and the maximum combustion pressure decrease distinctly with the increase of nitrogen fraction in the gas mixture. At the same ratios of nitrogen to gas mixture, Markstein length, unstretched laminar flame propagation velocity and unstretched laminar combustion velocity decrease and the maximum combustion pressure increase with the increase of initial pressure of the gas mixture. When nitrogen fraction in the gas mixture is over 20%, the flame will be unstable and is easy to exterminate.     

“数字化集中仓”模式下危化品仓储安全监管的演化博弈分析

针对利用数字化技术提高危化品仓储安全监管水平问题,考虑政府搭建“危化品集中式仓储中心+数字化网络监管平台”策略,基于演化博弈理论,构建危化品仓储安全监管演化博弈模型,分析建立数字化集中仓概率(本文简称“建仓概率”)对相关政府部门和危化品仓储企业行为演化规律的影响,探讨数字化集中仓模式下,危化品仓储企业合规仓储的驱动因素。研究结果表明：当建仓概率低于某临界值时,政府部门和危化品仓储企业会疏于监管违规仓储;随着建仓概率提高,政府部门和危化品仓储企业策略呈现周期性波动现象;当建仓概率很高时,虽然数字化集中仓一定程度上可提高政府监管便利性,但从长远看会使政府监管部门放松对危化品仓储安全的监管。研究结果可为政府推行数字化监管新模式和危化品仓储企业实施智能仓储管理提供一定决策支持。     

Digital Screening for Blood Alcohol Concentration (BAC) in a Southern Nigeria City

OBJECTIVE: Blood alcohol concentration (BAC) was digitally determined for transport operators, passengers, and pedestrians in a southern Nigeria city. METHODS: The subjects were screened with a digital breathalyzer, Alco Scan CA 2000, for BAC along major accident-prone highways, resting spots, and hospitals. The mouthpieces were complemented with disposable straws for rapid and hygienic screening of the subjects. RESULTS: Based on convenience sampling, a significant proportion of Nigerians has a BAC level above 0.06 on accident-prone highways (44.60%), at resting spots (54.50%), and in hospitals (47.80%). CONCLUSION: This research confirms that digital breathalyzer BAC levels are reliable and empirical means for determining incidents of alcohol-impaired driving.     

混凝土结构火灾损伤检测技术研究

对混凝土在火灾条件下的热像平均温升、抗压强度、超声波速和损伤深度进行了检测,获得了混凝土热像平均温升、抗压强度、超声波速和损伤深度随着温度变化的规律,并对影响混凝土热像平均温升和超声波速的因素进行了分析,为混凝土结构火灾损伤程度的现场检测提供了一种科学的技术方法。     

温压炸药弹内爆轰特性试验研究

研究温压炸药爆炸初期弹内爆炸波作用过程,可以进一步分析温压炸药分散爆轰的作用机理,为温压炸药武器设计和系统优化提供可靠依据.设计了用测时法研究温压炸药爆轰波传播速度的试验装置,并用探针对相同组分和密度条件下、温压战斗部弹内爆炸初期的爆炸作用过程进行了对比试验,记录了触发时间信号,计算并分析了温压炸药弹内爆炸波的传播特性,得到了波阵面与弹径方向夹角α的变化规律.试验结果表明,温压炸药的爆轰波传播速度为4.632km/s,其弹内爆轰波的传播特性与中心高能分散药的爆轰波有密切联系,通过合理设计弹体结构和比药量,可以实现温压炸药的分散爆轰,提高温压炸药的爆炸威力.     

Effects of vehicle impact velocity, vehicle front-end shapes on pedestrian injury risk

Objective: This study aimed at investigating the effects of vehicle impact velocity, vehicle front-end shape, and pedestrian size on injury risk to pedestrians in collisions with passenger vehicles with various frontal shapes. Method: A series of parametric studies was carried out using 2 total human model for safety (THUMS) pedestrian models (177 and 165?cm) and 4 vehicle finite element (FE) models with different front-end shapes (medium-size sedan, minicar, one-box vehicle, and sport utility vehicle [SUV]). The effects of the impact velocity on pedestrian injury risk were analyzed at velocities of 20, 30, 40, and 50?km/h. The dynamic response of the pedestrian was investigated, and the injury risk to the head, chest, pelvis, and lower extremities was compared in terms of the injury parameters head injury criteria (HIC), chest deflection, and von Mises stress distribution of the rib cage, pelvis force, and bending moment diagram of the lower extremities. Result: Vehicle impact velocity has the most significant influence on injury severity for adult pedestrians. All injury parameters can be reduced in severity by decreasing vehicle impact velocities. The head and lower extremities are at greater risk of injury in medium-size sedan and SUV collisions. The chest injury risk was particularly high in one-box vehicle impacts. The fracture risk of the pelvis was also high in one-box vehicle and SUV collisions. In minicar collisions, the injury risk was the smallest if the head did not make contact with the A-pillar. Conclusion: The vehicle impact velocity and vehicle front-end shape are 2 dominant factors that influence the pedestrian kinematics and injury severity. A significant reduction of all injuries can be achieved for all vehicle types when the vehicle impact velocity is less than 30?km/h. Vehicle designs consisting of a short front-end and a wide windshield area can protect pedestrians from fatalities. The results also could be valuable in the design of a pedestrian-friendly vehicle front-end shape. [Supplementary materials are available for this article. Go to the publisher's online edition of Traffic Injury Prevention for the following free supplemental resource: Head impact conditions and injury parameters in four-type vehicle collisions and validation result of the finite element model of one-box vehicle and minicar. ].     

基于组合赋权法的空管监视信息质量评估

为准确评估监视信息质量,给空中交通管制(ATC)提供决策依据,预防事故的发生,从目标航迹完整性、精确性、正确性等3个方面出发,构建由跟踪完整性、参数完整性、位置精度、速度精度、航向精度、参数正确性和目标真伪值等7个指标构成的监视信息质量评估体系;以总偏差最小为目的 将可拓层次分析法(EAHP)和熵权法有效结合确定指标权...     

煤层露头自燃火灾演化规律数值模拟研究

为解决煤层露头自燃所引起的资源浪费和环境污染,以新疆台勒维丘克煤层露头为研究对象,采用数值模拟方法研究煤层露头在火风压、火风压及外部风压作用下的自燃演化规律,为治理火区和保护环境提供依据。研究表明:火风压作用下,风流最大流动速度0.729 m/s,火风压最大达到170.2 Pa;火风压与外部风压联合作用下,煤层露头动力系统是负压通风系统,在漏风速度为0.2 m/s时,研究5个典型位置的温度、氧浓度、速度及压力的变化规律;并分析孔隙率、漏风速度对煤层露头自燃火灾的影响,说明大孔隙和漏风供氧为火灾大规模发展提供有利条件。研究成果对治理火区及保护生态环境奠定坚实基础。     

Computer professionals and Carpal Tunnel Syndrome (CTS).

Carpal Tunnel Syndrome (CTS) is an important problem among computer professionals. Hence the prevalence of CTS among computer professionals and risk factors were studied. 648 subjects were selected from 4,276 computer professionals from 21 companies by with simple random sampling method. CTS was diagnosed based on clinical features. The prevalence of CTS was found to be 13.1% (95% CI 10.5-15.7%). Subjects with over 8 years of computer work, over 12 hrs of work per day and system administrators were at a higher risk for CTS (OR 3.3, 4.9 and 2.5 respectively). Flexed or extended hand position had higher risk for CTS. Higher risk for CTS was found with higher exposure to computer work. Ergonomic considerations are important in facilitating proper positioning of hand while working with a computer. Further studies on CTS risk factors among computer professionals are essential for planning prevention.     

不同入口位置的行人进入流实验研究

为了研究行人进入流运动规律,寻找合理的入口位置,对不同入口位置(中间、右侧)进行了不同人数(10人、20人、30人、40人)的可控实验。分析了行人进入流的时间、速度和空间分布,并统计了空间分布影响因素——入口避让、边界吸引、分布角度和空间关系的规律。结果表明,入口位于中间的设计更好,进入时间和稳定时间较短,速度更快,空间分布更合理。这些影响因素的统计,也为行人进入流的模型建立提供了实验基础。     

Experimental and theoretical investigation of dry-water containing phosphoric acid for new fire suppressant

To overcome the shortcomings of phosphorus-containing compounds (PCCs, not widely used) in fire suppression, the dry water powder containing phosphoric acid was analyzed for a new fire suppressant (SiO₂-P). First, the fine conditions (solid-to-liquid ratio, stirring time and stirring speed) were determined to prepare the new powder. The particle size distributions and XPS of SiO₂-P powder were analyzed. The TG tests were conducted to study the decomposition of powder, and there was a major decomposition peak. Second, the extinguishing time of SiO₂-P powder was tested, which showed that the SiO₂-P powder containing phosphorus species could significantly improve the fire suppression ability. In addition, the kinetic parameters of powder decomposition reaction were determined by genetic algorithm based on TG results. Last, based on the decomposition products and kinetic parameters, the burning velocity and mass fraction of free radicals of CH₄/air flame with SiO₂-P powder addition were studied theoretically. The results indicated that SiO₂-P powder had great ability of reducing the burning velocity and scavenging free radicals. Furthermore, the suppression effects were analyzed, which indicated that the cooperation of H₂O and P suppression effect dominated the suppression mechanism and resulted in the good suppression efficiency.     

水幕流场特性诊断与隔热性能的实验研究

水幕系统作为一种新型的防火分隔方法,其自身参数对隔热性能有着重要影响。该文利用DPIV技术测量水幕的流场特性,水雾粒子的速度场分布,研究了水幕流场特性随喷头压力的变化关系;通过小尺度热态实验研究了水幕的隔热性能。研究结果表明：增大水幕厚度有助于提高阻隔效率,但是并不成线性关系;增大水幕压力、流量,可以提高水幕的隔热效率。     

不同封闭情况下T型管道中瓦斯爆炸传播规律实验研究*

为研究不同封闭情况下T型管道中瓦斯爆炸的传播规律,在90°分岔管道中进行瓦斯爆炸实验,管道封闭情况为弱封闭（双PVC薄膜弱封闭）和强封闭（直管封闭或支管封闭）。实验结果表明:在瓦斯浓度为9.5%时,管道中各点处的瓦斯爆炸压力、火焰传播速度和火焰锋面振荡幅度最大,11%次之,8%最小。T型管道中,弱封闭端瓦斯爆炸压力不断减小;火焰传播速度先缓慢增大后减小,随后又快速增大。强封闭端,瓦斯爆炸压力增大;火焰传播速度先缓慢增大后略微下降,随后快速增大后又大幅度下降,甚至出现火焰锋面振荡现象。不同封闭管道中各测点的瓦斯最大爆炸压力和火焰传播速度大小比较可知,直管封闭管道＞双PVC薄膜弱封闭管道＞支管封闭管道。     

Air bag effectiveness as function of impact speed

An investigation was conducted to estimate the effectiveness of air bags as a function of velocity. The study consisted of three parts: a theoretical idealization, an analysis of National Automotive Sampling System/Crashworthiness Data System (NASS/CDS), and a reanalysis of previously published Fatality Analysis Reporting System (FARS) data. The theoretical analysis looked at idealized risk curves as a function of velocity; assuming that the air bag offers a benefit for both belted and unbelted occupants. Analysis of the NASS/CDS data looked at the effectiveness of air bags as a function of velocity for Maximum Abbreviated Injury Scale (MAIS) 3+ injuries. The reanalysis of the previously published FARS data looked at the effectiveness of the air bag as a function of velocity for fatalities. The theoretical analysis indicates that the air bag effectiveness should be greatest at the low velocities. The field data analysis of both NASS/CDS and FARS were consistent with the theoretical analysis, indicating that air bags are most effective at the lower velocities, below 40 kph (25 mph), for both belted and unbelted occupants. Although it was not possible to estimate a different effect for belted and unbelted for fatalities using FARS, it was possible for MAIS 3+ using NASS/CDS. For unbelted occupants the effectiveness goes to zero or becomes negative above 40 kph (25 mph) for MAIS 3+, and for belted occupants the effectiveness stays positive but with significantly lower magnitude for speeds above 40 kph (25 mph).