南京长江隧道火灾数值模拟

以南京长江隧道为研究背景,运用火灾动力学模拟软件PYROSIM建立实体物理模型,并将空间划分为0.1 ×0.1 ×0.1m3的网格,对南京长江隧道火灾过程中的纵向通风进行模拟计算.定量分析了不同通风速率条件下火灾及烟气蔓延的规律,并得到隧道拱顶附近温度和烟气分布状况.模拟结果显示较小风速下烟气会产生回流,但随着风速增大烟气扩散速率随之加快,通过对3种不同风速的分析比较,选择3.0m/s纵向通风作为临界风速.进一步结合南京长江隧道现有的消防设施及应急救援系统,分析该临界风速下烟气温度对隧道结构和毒害气体对人员疏散救援的影响.结果显示此临界风速下隧道结构安全,且在疏散及时、救援有效的基础上,基本能保证人员疏散安全.     

考虑抢行行为的恐慌状态人员疏散研究*

为研究恐慌状态下人员抢行行为对整体疏散效果的影响,建立考虑抢行行为的恐慌状态人员疏散元胞自动机模型,基于恐慌情绪算法将人员分为恐慌者和非恐慌者,通过改变恐慌者抢行概率体现抢行行为,并模拟仿真分析初始人员密度、恐慌情绪转化、抢行概率对人员疏散影响,对疏散过程中特殊现象进行分析。研究结果表明:人员密度适中时,抢行行为能够减少恐慌者数量,加快恐慌者转换进程,疏散时间随抢行概率增加而减小,疏散过程中存在恐慌聚集和两端疏散现象。研究结果可为突发事件下人员紧急疏散提供理论支持。     

Amalgam in Dentistry A Health Hazard for Dental Personnel?

In a cross sectional study done in 1993 among dental personnel in Norrbotten, self-reported prevalence of muscular pain, headache, tremor, insomnia, irritation, impaired memory and depression, as well as information regarding different mercury exposures were collected Mercury exposures were determined as “number of amalgam fillings in teeth,” “years in practice,” “insufficient ventilation at work,” “total number of amalgam removed, produced and polished per day,” and “working in dental clinics.” As controls, physicians and nurses from the same geographical area were selected. The correlation between symptoms and different mercury exposures was calculated using logistic regression. The results suggested a higher prevalence of muscular fatigue and tremor for female dental personnel compared to controls Controls reported a lower prevalence of symptoms with increasing number of amalgam fillings in teeth. There was no correlation between the number of amalgam fillings handled per day and symptoms for dental personnel. Male dental personnel associated muscular fatigue headache, impaired memory, and depression with increased handling of amalgam in the clinic’ whereas the female dental personnel associated the same symptoms with the number of amalgam fillings in teeth. The strongest correlation was found between symptoms and insufficient ventilation at dental clinics for dental personnel.     

Symptoms and musculoskeletal diseases in hospital nurses and in a group of university employees: a cross-sectional study

Background. Most studies have shown that nurses have a higher risk of developing musculoskeletal symptoms compared with other occupational groups. Aim. A cross-sectional study was performed to gain more insight into the prevalence rates of musculoskeletal disorders (MSDs) in nurses. Methods. The presence of musculoskeletal symptoms was revealed by personal interviews in a sample of 177 hospital nurses and in a reference group of 185 university employees. Musculoskeletal diseases were based on radiological examinations in all subjects. Results. Lower back pain (61% vs 42.2%) was the most frequently reported symptom, followed by neck pain (48.6% vs 38.4%) and shoulder pain (36.7% vs 25.9%), with a significantly higher prevalence in nurses. Women had about a 2-fold risk of upper limb region and neck pain compared with men. The most common abnormal findings on radiological examinations were disc herniations (n?=?40). Conclusions. Nurses showed a significantly higher risk of MSDs. Prevalence rates in nurses increased significantly with age. Musculoskeletal symptoms were also common in university employees. This suggests the need for effective intervention strategies involving workers’ active participation, in order to improve the process and organization of work and promote a positive psychosocial work environment.     

社区治安高危人员异常轨迹识别与预警方法研究*

为解决社区治安高危人员异常轨迹难以实时感知、精确识别、及时预警的问题,对社区治安高危人员动态轨迹进行标定,并建立动态轨迹序列化模型,通过序列化模型构建动态行为链;根据静态身份属性与动态轨迹时空特征信息,建立异常轨迹分析模型。结果表明:动态轨迹标定可实现对GPS轨迹数据高效、准确标定;异常轨迹分析模型可实现异常轨迹识别与预警。研究结果适用于社区高危人群管控,可为社区治安防控提供技术支持。     

农村环境监测存在的问题及建议——以敖其村为例

通过对敖其村地表水、饮用水源地、环境空气、土壤进行调查,发现作物种类改变、监测点位变化、专业人员匮乏、经费来源紧张等问题制约了农村环境质量监测工作的开展,建立固定监测点位、加强人员培训、加大经费投入等措施可以有效解决农村环境质量监测中存在的问题,保证监测工作的顺利开展和进行。     

导流栏杆设置对地铁岛式站台人员疏散的影响分析

为研究导流栏杆设置对地铁岛式站台人员疏散效率的影响,选取不同出口分布类型的地铁岛式站台为研究对象,基于BuildingEXODUS软件进行数值模拟,分析导流栏杆设置对不同出口分布类型地铁岛式站台人员疏散的影响.研究结果表明:A型站台在设置导流栏杆后,人员疏散时间均有所增加,导流栏杆设置长度为2,4 m时,人员疏散时间增...     

神经网络模型在环境监测机构编制管理中的应用研究

根据非线性化现代神经元理论 ,以湖北省三、四级环境监测站为例 ,建立了神经网络定量测算人员编制的模型。研究确立了反向传播 BP模型在测算人员编制中的应用方法及技术路线。采用所建模型对某部门、某单位人员编制测算具有操作方便灵活 ,准确可靠以及实用性、通用性和动态可操作性特点。不仅可指导环保系统机构实现科学化定编、定员 ,同时对其他事业单位编制的规范化管理亦有参考意义。