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51.
通过对钻孔过程中的钻头破煤机理及影响钻杆转速变化的因素进行理论分析,提出了钻进速度与钻杆转速的对应变化关系,并利用钻进装置、加载装置及自主研制的钻孔多参量测试装置进行试验分析,验证了利用钻杆转速法测定煤体应力大小的可行性,同时对不同钻进速度下钻杆转速的变化规律进行研究。结果表明:在钻头、钻杆、煤岩体参数及钻孔前钻杆空转转速一定时,钻杆转速与钻进速度大致呈现负指数的函数关系,钻进速度越小,钻杆转速越大,反之,钻杆转速越小。研究钻进速度对钻杆转速的影响,可以减少利用转速指标对冲击地压等动力灾害的预测误差,实现高效预警。  相似文献   
52.
为研究岩爆事件的声发射特征,为岩爆灾害的进一步监测预警提供依据,对五老峰隧道掌子面附近区域岩爆事件进行声发射监测,以RA均值作为主要参数,研究岩爆发生前后的参数变化规律,并通过与b值等参数分析结果的相互印证,对比岩爆信号与爆破震动信号之间的区别。试验结果表明:不同传感器因为布设位置、耦合程度的差异,接收到的声发射信号数量与参数分布范围存在较大差异;RA均值作为参数分析依据,能够较好地反映岩爆事件的孕育发展过程,且能够一定程度上消除传感器接收信号数量差异的影响,更稳定地反映岩爆事件的信号特征;岩爆事件发生前RA均值与事件密度不断升高,峰值后则都迅速降低,而爆破产生的声发射信号则在RA值上存在一定突变性,且峰值后仍保持较高水平。本次监测中,共发生1次微型岩爆,而在左洞爆破后,声发射信号明显增多,但并未产生显著破裂事件。  相似文献   
53.
为研究高压水射流卸压防治复合动力灾害的可行性,以余吾煤业高瓦斯矿井东翼采区内首采N2105工作面工程地质条件为背景,通过现场调研、理论分析、数值模拟和工业性试验等方法,对N2105进风平巷两帮采取高压水射流卸压防治效果进行了研究。结果表明:对巷帮煤体采取高压水射流卸压技术,煤体在高压水射流的冲击力和扰动应力波共同作用下瞬间发生破坏;巷帮侧支承应力分布曲线由原有的“单高峰值”转变为“内低外高双峰值”,受以上支承应力变化的影响,底板煤岩体内难以形成范围较大且连续的塑性应力状态区;现场电磁辐射和矿压监测结果表明高压水射流技术对煤层卸压增透效果显著,降低了巷道发生复合动力灾害的可能性。研究结果可为同类矿井复合动力灾害的防治提供参考和借鉴。  相似文献   
54.
室内燃煤取暖与烟雾程度对呼吸道健康的影响研究   总被引:2,自引:1,他引:1  
在儿童家庭调查问卷的基础上 ,报告室内燃煤取暖与烟雾污染程度对呼吸系统病症的影响。结果表明家庭燃煤取暖与否、室内空气烟雾程度对儿童及其父母的呼吸系统健康有不利的影响  相似文献   
55.
室内外空气污染对学龄儿童呼吸系统影响的研究   总被引:6,自引:0,他引:6  
通过对污染区和对照区 2 0 0 0多名学龄儿童呼吸系统症状、疾病患病率比较 ,并运用非条件 Logistic回归分析方法 ,就室内外空气污染对学龄儿童呼吸系统健康的影响 ,进行了研究。结果显示 ,污染区室内外空气污染较严重 ,大气中TSP、SO2 和 NOx 的浓度均超过国家二级标准 ,其儿童呼吸系统症状、疾病患病率明显高于对照区。对儿童呼吸系统发病有显著影响的环境因素是 :大气污染、被动吸烟、家庭燃煤、冬季取暖和室内油烟污染程度。其中咳嗽与以上五个因素有显著的正相关关系 (P<0 .0 5) ;除被动吸烟外 ,支气管炎与其它四个因素呈显著正相关 (P<0 .0 5) ;咳痰与大气污染、被动吸烟、冬季取暖和室内油烟污染程度 ,气喘和呼吸系统疾病住院率与大气污染和室内油烟污染正相关关系显著 (P<0 .0 5)。哮喘与室内外空气污染无显著的统计学联系  相似文献   
56.
兰州市空气污染对儿童及其父母呼吸系统健康的影响   总被引:4,自引:0,他引:4  
叙述了居住环境对儿童和儿童父母亲呼吸系统健康影响的研究结果。揭示了儿童对空气污染所引起的呼吸系统疾病的急性反应较成人更敏感。吸烟合并空气污染更能损害人的健康  相似文献   
57.
概述了海洋溢油应急处置的技术方法,分析了溢油应急处置装置设备的应用特点,为海洋溢油应急处置工作提供理论依据。  相似文献   
58.
Since the damage suffered by buildings as a consequence of explosions usually affect the people inside them, it is important to take it into account when performing consequence analysis. The aim of this paper is to provide a methodology to estimate consequences to buildings from pressure waves produced by spherical vessel burst. This is done by combining characteristic overpressure–impulse–distance curves [González Ferradás, E., Diaz Alonso, F., Sanchez Perez, J.F., Miñana Aznar, A., Ruiz Gimeno, J. and Martinez Alonso, J., 2006, Characteristic overpressure–impulse–distance curves for vessel burst, Process Safety Progress, 25(3): 250–254] with PROBIT equations. The main advantage of this methodology is that it allows an overview of all the magnitudes involved, as damage is shown in the same graph as the overpressure, impulse and distance. In this paper diagrams and equations are presented to determine minor damage to buildings (broken windows, displacement of doors and window frames, tile displacement, etc.), major structural damage (cracks in walls, collapse of some walls) and collapse (the damage is so extensive that the building is partially or totally demolished).  相似文献   
59.
Respiratory health of road-side vendors in a large industrialized city   总被引:1,自引:1,他引:0  
GOAL, SCOPE AND BACKGROUND: The literature reports a high prevalence of respiratory symptoms associated with exposure to motor vehicle exhaust emissions and people exposed to vehicle emissions are at risk of reduced lung function and cardiovascular performance. Although the effect of traffic emissions is a known risk to respiratory health, retailers are often situated along major roads in a busy urban environment to maximise customers. Shop assistants in an air-conditioned environment should be less exposed to traffic fumes and their lung function should be better preserved compared to 'unprotected' vendors exposed directly to vehicle emissions. The lung function of these two groups of workers has not previously been compared. The aims of this study are to determine if there is a difference in the concentration of respirable particles of diameter less than 10 micrometers (PM10) inside and outside air-conditioned shops along a busy major road; and to compare the lung function parameters, blood lead levels and respiratory symptoms between road-side vendors directly 'exposed' to traffic fumes and vendors working in 'protected' air-conditioned shops along the same road. METHODS: Roadside vendors (n=33) and adjacent shop assistants (n=31) were recruited for the study in a district known to have high emissions and pollution measures. All subjects were asked to complete a questionnaire providing the frequency of their respiratory symptoms. Spirometry pulmonary function tests were conducted and exhaled carbon monoxide levels (ECO), oxygen saturation and blood lead levels (BLL) were measured. PM10 level was concurrently measured in the subject's working environment. Pulmonary function data and ECO levels collected from a cohort of university staff aged > or = 30 years (n=92) at a university campus were included for comparison. RESULTS: The concentration of particulate matter (PM10) at the roadside (210 +/- 70 microg/m3) was significantly higher than inside the shops (130 +/- 40 microg/m3). There was no difference in lung function parameters or BLL between the groups, however the forced vital capacity of both groups of vendors was significantly lower than a 'control' cohort of academic institution personnel (n=92). DISCUSSION: This study illustrated that while the level of pollution improved with air conditioning, this may not be sufficient to prevent respiratory consequences. Our data suggests that a reduction in occupational exposure is not enough to protect these workers. CONCLUSIONS: Air-conditioned work environment is insufficient to protect the respiratory system against the adverse effects of exposure to vehicle emissions. RECOMMENDATIONS: The overwhelming effect of exposure during travel to and from work and at home cannot be underestimated. More stringent guidelines to control pollution appear necessary to protect the respiratory health of both shop-keepers and road-side vendors and further studies to explore the effect on respiratory health of the exposure to pollutants associated with commuting to and from work are warranted.  相似文献   
60.
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