多传感器耦合区域火灾报警技术研究

早期预警与低误报率一直是建筑火灾探测面临的挑战与难题。已有研究多针对特殊场所特定燃烧产物或多种传感器耦合,普适性不强,探测设备成本高,无法大规模应用。通过将火灾烟气蔓延规律与探测器信号时空分布融合,在不增加探测器数量和分布的情况下,提出了一种基于建筑结构微元的多传感器耦合区域火灾报警模型。对典型火灾场景的烟气蔓延情况进行了模拟分析,狭长结构中探测器信号强度变化具有一定的规律性。应用区域火灾报警模型后,报警时间较传统模式提前了14.7%,基本杜绝了单个探测器误报引发建筑物火灾报警的问题。结果表明:多传感器耦合探测模式显著缩短了火灾报警时间,降低了火灾探测误报率,实现了火灾的早期准确识别与预警。     

基于直觉模糊集的城市供水安全预警评价模型

为了更好地评价城市供水安全预警的等级,基于直觉模糊集理论,建立城市供水安全预警评价模型。模型选取12个评价指标构成属性集,预警等级划分标准构成评价等级集,再将二者转换为直觉模糊数,以此构成直觉模糊决策矩阵,并综合主、客观权重的优势得到组合权重,以此计算样本综合值,最后分析指标权重变化对于评价结果影响的灵敏度。实例计算结果表明:基于直觉模糊集的城市供水安全预警评价与可拓物元分析法的结果总体接近,2006—2009年供水安全预警等级处于重警或中警等级,2009年以后预警等级降低并基本稳定在无警这一等级。不同指标的敏感性分析有助于提高权重的准确性。     

震源车主动防侧翻预警系统研

为了防止震源车在野外行驶过程中发生侧翻事故,实现对震源车危险状态的提前预警,迫切需要开展震源车主动防侧翻预警系统研究。基于震源车不同工况下的侧倾稳定性分析,结合国内外现有车辆侧翻预警指标特点,采用多级判断原则,建立了一种能综合判断不同行驶工况的震源车侧翻预警指标A和主动防侧翻预警系统,并通过MATLAB/simulink软件对该预警系统进行仿真模拟分析。研究结果表明:震源车侧倾稳定性随转弯速度、转向角、坡度角等参数的增大而呈现降低趋势;同时,该预警系统能通过侧翻预警指标A实现对震源车平路转向和斜坡转向过程中的行驶状态进行准确判断,并发出不同级别的声光报警。此研究将为进一步开展震源车预警系统的试验研究奠定理论基础。     

Noise exposure as related to productivity, disciplinary actions, absenteeism, and accidents among textile workers

A sample of 2458 workers exposed to average noise levels ranging from 80 to 99 dBA in different operations of three textile mills was studied with respect to their productivity, work rule violations, absenteeism, and accidents. The three mills were in rural, suburban, and urban locations. Noise exposure levels were measured in individual departments of the mills, and workers were interviewed to ascertain socioeconomic background, work history data, and health status. Workers' job attitude was rated by their supervisors, and data about their productivity, disciplinary reports, absenteeism, and accidents were collected from plant records. Results of the study suggested that workers in departments with high noise levels (above 90 dBA) had more disciplinary actions and absenteeism and lesser productivity than those in departments with low noise exposure (below 90 dBA). Disciplinary actions showed the greatest difference between the high-noise and low-noise departments followed by production incentives, production efficiency, and absenteeism. Noise appeared to affect the quality of work as reflected by disciplinary actions for material damage, and this effect was higher in weaving and spinning operations which involved vigilance tasks. The frequency and severity rates of accidents in highnoise departments were greater than in low-noise departments. Certain personal and socioeconomic factors affected high vs. low noise exposure differences found among workers for the investigated variables. These effects were most apparent for absenteeism and, to a lesser extent, productivity. Disciplinary actions did not appear to be influenced by any such individual factors. It was concluded that noise abatement in the textile industry could be beneficial to worker productivity and well being and contribute to more economically effective operation.     

考虑可靠性的矿井瓦斯传感器选址模型

针对依据现行煤矿安全规程及相关规范布置的瓦斯传感器有可能出现失效的情况,提出兼顾经济性和可靠性双目标的瓦斯传感器优化选址模型。借助图论和设施选址理论,以矿井通风网络节点为候选布置点,节点间的风流流经时间为监测等级,以煤矿相关规程规范硬性要求的布置点为必选点,建立瓦斯传感器多目标优化选址模型。然后,基于Pareto蚁群算法(PACA)阐述模型的求解过程。最后,结合某风网算例,给出模型与算法的具体应用。结果表明:模型的非劣解包含了传统的以最小化传感器成本为目标的选址模型最优解,并且可靠性越高所需的传感器就越多。     

Perceptions of implied hazard for visual and auditory alerting signals

Visual and auditory alerts are increasingly important and have many applications, particularly in the presentation of hazard information in transportation and many industrial systems. This paper is concerned with the factors that govern the relative effectiveness of alerting signals involving various combinations of visual and auditory signals. The visual variables were colour, flash rate, and flash mode, combined with or without an auditory alarm. It was found that the subjects associated different levels of hazard with different alerting light colours, flash rates, flashing modes, and with combinations of auditory and visual alerts. A red flashing light was perceived as the most effective hazard warning colour, with yellow and blue warning lights indicative of less hazardous situations. The faster the flash rate, the greater is the hazard perceived. A flash rate of 60 fpm (flashes per minute) was not as effective as the rates of 180 and 240 fpm, and 240 fpm was the most effective. This implies that hazard warning signal should flash at well above 60 fpm. Having a breakup in the flashing pattern so as to provide a double or triple flash mode also increases the effectiveness of the signal. There were significant interactions between the alert variables used. The difference in perceived hazard levels for the colours blue and yellow were statistically non significant, but blue was more effective in conveying hazard message than yellow at the high flash rates. When accompanied with auditory alarms, blue and yellow were perceived to convey the same perception level of hazard as red without auditory alarms. The effect of colour on perceived hazard was also found to vary with flash mode. As compared to either visual signal alone or a visual signal with other types of acoustic alarms, a siren type of auditory alarm was found more effective for eliciting perception of hazards. There was evidence that presenting alerting signal in triple-flash mode and at high flash rate could be annoying and might not help improving hazard awareness.     

Health impact and noise exposure assessment in the cricket bat industry of Kashmir,India

Aim. The aim of the present study was to identify and evaluate predominant noise sources in the cricket bat industry of Kashmir, India. Methods. Sound levels were measured at operator’s ear level in the working zone of the workers of seven cricket bat factories. The impact assessment was made through personal interviews with each worker separately during their period of rest. Results. On average, 62.5% of the workers reported difficulty in hearing and 24.1% of the workers have become patients for hypertension. Only 58.1% of the workers complained of headache due to high noise level. Conclusions. The workers engaged in the cricket bat industry of Kashmir are exposed to high noise levels. It is suggested that personal protective equipment like ear plugs and ear muffs be used by these workers as a protection against this hazard.     

某垃圾焚烧热电联产项目职业病危害控制效果评价

对某垃圾焚烧热电联产项目职业病危害控制效果进行评价,确定其主要的职业病危害因素。根据项目职业病危害的特点,通过职业卫生现场调查、职业卫生检测、职业健康检查等方法收集数据和资料,并结合职业病防护设施、个人职业病防护水平和定量分级结果,对试运行期间作业人员的职业病危害因素接触水平及职业健康影响进行评价。该项目主要职业病危害因素有硫化氢、氨、氢氧化钠、氯化氢、氟化氢、粉尘、一氧化碳、二氧化碳、NOX、SOX、重金属（如铅、汞、镉等）、二噁英等有毒气体（或有毒粉尘）和噪声、高温等物理因素。项目除输煤系统4#皮带头作业点煤尘浓度和5#皮带头、5#皮带卸煤口、碎煤机（三楼）检测点的噪声强度不符合国家职业卫生标准外,其余均符合国家职业卫生标准。该项目职业病危害控制效果基本符合国家职业卫生标准。建议改进完善部分岗位的职业病防护设施,建立健全职业卫生管理制度,完善现场职业病危害警示标识和警示说明。     

基于声信号特征分析的燃气管道探测识别方法

为了探测和辨识地下燃气管道,避免燃气管道改扩建的过程发生第三方破坏引发安全事故,提出1种基于声信号特征分析的燃气管道探测识别方法,该方法考虑燃气管道声信号声压级低以及易衰减的特点,采用Hilebert-Huang变换算法分析燃气管道流噪声信号特征,建立燃气管道流噪声信号的特征数据库,并通过BP神经网络进行模式识别,判别...     

济钢中板厂精整区噪声污染的分析与对策

分析了济钢中板厂精整区噪声污染严重的原因。采取了吸音材抖、消声设备、加强个体防护等措施,使总声压级由105dB降到72dB,保护了职工的身体健康。     

Noise generated by multiple-jet nozzles with conical profiles 287

Conical multiple-jet nozzles, which reduce the risk of nozzle openings being blocked, are tested for their effectiveness in noise reduction. Nozzles with different exit spacings are tested. It is found that the multiple-jet design significantly decreases noise levels in the audible range by shifting emitted sound power to higher and ultrasonic frequencies. No significant difference in noise characteristics between exits distributed on a flat plane and beveled exits on a conical surface is observed. When the exits are more densely distributed, there is a trend of spectra shifting back toward the low frequency. This phenomenon is found to increase sound levels in a certain range of frequencies much lower than the peak one. Although this increase contributes little to the total emitted sound power, it is an important factor in determining the sound levels of audible noise.     

高海拔矿井风机气动噪声数值模拟及实验研究

为研究高海拔矿井风机气动噪声规律，建立小型轴流风机三维物理模型，利用CFD软件对环境气压分别为1，0.9，0.8，0.7，0.6及0.5 atm时的风机模型进行定常模拟、非定常模拟及噪声计算，并通过自主设计的压变实验装置对上述不同环境气压条件下风机转数分别为500，1 000，1 500和2 000 rpm时的风机噪声进行测试，分析风机叶片附近监测点噪声频谱曲线及压变环境风机噪声实验数据，结果表明:风机转数和环境气压是影响风机气动噪声的2个重要因素；环境气压P一定时，风机转数n越大，各频率下的风机气动噪声声压级SPL越大，且风机噪声总声压级Lp和平均声压级Lavg均随风机转数n的增大呈对数函数增加；风机转数n不变时，随着海拔高度的升高，环境气压P降低，各频段下风机气动噪声声压级SPL均将减小，且风机噪声总声压级Lp和平均声压级Lavg随环境气压值P的降低呈线性函数减小，环境气压每降低0.1 atm，二者分别降低1.47和1.29 dB。     

20种护耳器噪声防护效果的探讨

探讨了国内外２０种护耳器对石油钻井噪声的防护效果。首先在隔声室内模拟石油钻井工人接触的噪声环境，声级达１０３ｄＢ（Ａ）。采用护耳器主观测量方法对每种护耳器进行噪声防护效果测量，并筛选出噪声防护效果明显的几种护耳器。     

基于CAN总线的新型煤矿粉尘浓度检测系统的研究

为了实现对粉尘的实时在线检测和粉尘超限报警,以及实现煤矿粉尘浓度检测系统的高性能运行,本文设计了一种基于CAN总线的新型煤矿粉尘浓度检测系统.本文首先对粉尘浓度检测系统的整体设计方案进行了描述,然后对系统的传感器及调理转换电路、声光报警电路和CAN通信电路等硬件电路进行了设计,对粉尘检测系统的软件进行了详细的设计分析.最后给出了实验结果,并通过实验结果证明了该系统能长时间实时监测粉尘浓度,并通过CAN总线接口可以实现系统的远距离、高可靠性通信功能和远程监控功能.本系统具有测量准确、速度快、可靠性高和能及时报警等特点.     

铁路一线职工心理健康评估及风险预警模型研究

对某铁路机务段420名一线职工进行心理健康状况的现况研究并探索其影响因素,初步建立心理健康风险评估模型。整群抽取420例样本,采用症状自评量表(SCL-90)进行心理健康水平测评,与全国常模比较,采用二分类Logistic心理健康风险预警模型进行回归分析。结果表明,铁路一线职工在躯体化、饮食睡眠情况、敌对、强迫症状方面的得分均高于全国常模。年龄、文化程度、现职工种、劳动班制、工龄等因素影响职工心理健康状况。进而提出应做好职工心理疏导工作,探索一线职工心理健康预警指标,实现风险识别关口前移,保障铁路运输安全。     

Theoretical predictions and actual hearing threshold levels in workers exposed to ultrasonic noise of impulsive character--a pilot study.

Results of standard pure-tone audiometry (PTA) were collected from 25 workers, mainly females, aged 23-58 years, exposed for 2-13 years to ultrasonic noise emitted by ultrasonic welders. Hearing tests were completed by evaluation of exposure to ultrasonic noise. The subjects' actual audiometric hearing threshold levels (HTLs) were compared with theoretical predictions calculated according to ISO 1999:1990. In 60% of cases sound pressure levels in the 10-40 kHz 1/3-octave bands at workstands exceeded Polish exposure limits for ultrasonic noise. Our comparison of predicted and measured HTLs suggests that the ISO 1999:1990 method, intended for audible noise, might also make it possible to predict reliably permanent hearing loss (in the 2000-6000 Hz frequency range) after exposure to ultrasonic noise. No significant progress of hearing impairment (assessed using PTA) in the operators of ultrasonic welders was noted. Nevertheless, further studies on the hearing status of workers exposed to ultrasonic noise are needed.     

Design of Optimal Noise Hazard Control Strategy With Budget Constraint

An analytical design procedure to determine optimal noise hazard control strategies for industrial facilities is presented. Its objective is to determine a set of appropriate noise controls to eliminate or reduce noise levels so that workers ‘ daily noise exposure does not exceed a permissible level. From a given noise control budget, engineering controls will be firstly implemented, followed by administrative controls, and then the use of hearing protection devices. Six optimization models are developed and sequentially applied to select appropriate noise controls without exceeding the budget. Numerical examples are presented to demonstrate the application of the proposed design procedure.     

有限空间作业人员生理状态监测设备研制

为监测有限空间作业人员异常生理状况,进而保障有限空间作业安全与作业人员生命健康,在分析手腕处6个测量位置信号质量的基础上,获得最佳信号采集位置,并结合事故成因,从光电容积脉搏波(PPG)信号中提取心率、脉搏周期、振幅等生理参数作为评价指标,研制一款针对有限空间特殊作业人群的手腕处脉动生理信息监测设备;并进行系统稳定性测试。研究结果表明:手腕内侧中心位置为信号最佳采集位置;在有限空间运动状态下设备性能良好;研制的设备可以实现人员生理状态的实时无创监测与预警。     

基于粗神经网络的管制员工作差错风险预警模型

针对空中交通管制员工作差错风险类型,指出指标体系建构过程的动态性特征,从个人、团队、设备、环境及管理几个方面,建构预警指标体系,运用粗糙集在数据挖掘方面的优势,通过基于属性重要度的启发式约简算法,提取关键指标,剔除冗余指标,可以实现在不丢失关键预警监控对象的情况下,结合BP人工神经网络构建实时预警模型,既有利于加快运算速度,又有利于进行重点监控.经过实例仿真,粗糙集与BP网络结合建构的预警模型,能有效针对管制员工作差错风险进行实时预警监控.