共查询到20条相似文献,搜索用时 109 毫秒
1.
2.
工程机械在冬季使用时,因气候寒冷,易导致内燃机起动困难,冷却水和电解液冻结,零部件磨损加剧,燃油消耗量显著增加,因此,在入冬之前必须采取相应的保护措施,加强维护,确保设备的安全正常使用. 相似文献
3.
世界文化遗产、流传千古的凝固音乐—布达拉宫,建筑在西藏拉萨市中心的布达拉山上。布达拉,是观音胜地普陀洛迦的梵语译音,意思是持航或航行解脱海岛之舟,表示观音持航以普救众生。布达拉山最早叫红山,有着坎坷的经历,辉煌的历史,公元6世纪,雅砻部落第27代赞普拉脱脱日年赞“居拉萨红山之顶”。公元7世纪之初,松赞干布迁都拉萨,“筑王宫于红山顶居之”。之后,大兴土木,建造偌大的城堡,“高达30围墙,既高且阔,每边一里余”,“城的四面有四道门,各有门楼,每门设岗”,“红宫900,合顶之王宫,共1000间,一切宫檐,以宝为饰,走廊台阁,铃铎泠然。”(… 相似文献
4.
浙江省嘉兴市余南村位于嘉兴市南部,距嘉兴市区9公里,地处余新镇区之南,北靠余新镇余贤大街,中心村距余新镇区仅6公里,属镇郊村.余南村西临海盐塘,东部设有乍嘉苏高速公路余新出口,水陆交通十分便利.全村区域面积5856平方公里,有耕地3209亩.到2005年底,全村有36个自然村,18个村民小组,860户,总人口2525人.有劳动力1580人,男劳动力760人,女劳动力820人,其中在本村企业就业的有460人,占全村劳动力总数的29.11%,70%的劳动力在村内和镇内就业.全村外来人口2806人,主要在村内企业就业.村内有个体私营企业129家,主要生产五金、塑料,有个体种养大户7户.2005年工农业总产值38973万元,其中,农业产值2695万元,工业产值36103万元,第三产业产值176万元. 相似文献
5.
6.
7.
8.
9.
10.
11.
12.
结合人工挖孔桩特点,对其施工过程中的质量管理进行了探讨,分别阐述了护壁、井圈施工、挖桩、钢筋笼、桩身混凝土浇筑等关键环节的质量控制措施,对促进人工挖孔桩在建筑工程中的推广应用具有积极意义。 相似文献
13.
以鄂尔多斯市呼吉尔特矿区葫芦素副立井为工程实例,详细阐述国内首个基岩冻结新型单层井壁的施工工艺和监测方法,对井壁施工过程中的技术难点进行分析,给出井壁混凝土的质量控制指标。现场实测表明:(1) 凿井期新型单层井壁的钢筋应力和混凝土应变同时受基岩冻结压力与井壁温度的影响;(2) 井壁钢筋应力、混凝土应变的变化过程可分为OA,AB,BC,CD共4个阶段;(3) 凿井期葫芦素副立井竖向钢筋拉、压应力极值分别为35.5~70.8和-7.0~-45.0 MPa,环向钢筋则始终处于受压状态,其压应力极值为-41.7~-101.0 MPa;(4) 凿井期混凝土竖向、环向压应变极值分别为-190.5~-458.0和-590.4~-799.1 με,环向压应变极值为竖向的1.3~4.2倍;(5) 建议将竖筋悬吊的井壁高度取为12 m;(6) 葫芦素副立井井壁配筋于凿井期具有足够的安全储备,混凝土压应变处于安全范围。 相似文献
14.
15.
The authors conducted a series of wood crib burnout tests to determine the emissivity and convective heat transfer coefficient
of wood crib flames. These values can be used to calculate heat transfer between flames and exposed structural members. 相似文献
16.
新型干水灭火剂因其高含水量和特殊核壳结构,具有良好的灭火效果。为探究干水对木垛火的灭火效果,自行制备磷酸二氢铵改性干水并开展小尺寸木垛火灭火试验。结果表明:干水灭火剂能够扑灭小尺寸木垛火且不发生复燃,改性干水的控火时间仅为8 s,控火过程中火焰高度持续快速下降,而干粉灭火剂的控火时间则为20 s,喷撒结束39 s后发生复燃;改性干水对火焰区及木垛的温度抑制效果均优于干粉灭火剂,控火时间内,改性干水作用下木垛表面的平均温降速率高达17.00℃/s,是干粉灭火剂作用下平均温降速率的1.94倍;改性干水能够有效降低木垛内部温度,在喷撒50 s内,木垛中心的平均温降速率为8.78℃/s,而干粉灭火剂缺乏冷却作用,木垛中心的平均温降速率仅为6.10℃/s,无法有效抑制阴燃。 相似文献
17.
18.
19.
Curtis T. Ewing Francis R. Faith James B. Romans Charles W. Siegmann Ralph J. Ouellette J. Thomas Hughes Homer W. Carhart 《Fire Technology》1995,31(3):195-211
We investigated the extinguishing properties of multipurpose dry chemicals using openregime cribs of two sizes. One measured 20.3 by 20.3 by 15.2 cm, and the other 50.8 by 50.8 by 38 cm. A crib fire, which has both flaming and smoldering contributions, is primarily extinguished when the burning surfaces are covered or smothered by a gas phase of the original multipurpose agent or a product of the agent's decomposition. The overall effectiveness of each dry chemical depends on its particle size, the degree of its decomposition and/or vaporization, and the openness of the crib. All particles of an agent below a unique limiting size completely decompose and/or vaporize in the crib fire and have the same extinguishing effectiveness. Particles above the limit have no measurable effectiveness. Scaling is considered on the basis of the minimum extinction weight per unit of exposed wood surface.Carhart is recently retired from the U.S. Navy Technology Center for Safety and Survivability at the Naval Research Laboratory in Washington, D.C. 相似文献
20.
Haukur Ingason 《Fire Safety Journal》2008,43(7):512-528
A model scale study (1:23) was carried out in order to improve the basic understanding of water spray systems in longitudinal tunnel flow. The water spray system consisted of commercially available axial-flow hollow cone nozzles. Tests with both a deluge system made of 12 nozzles placed directly above the fire source and a water curtain system consisting of four nozzles placed either downstream or upstream of the fire source were carried out. A wood crib was used to simulate the fire source, which was designed to correspond to a HGV (heavy goods vehicle) fire load in large scale. A second wood crib was used as a target pile and was placed downstream the ignited wood crib. The parameters varied were the water flow rate and water pressure, the longitudinal ventilation rate and the arrangement of the nozzle system. Possible fire spread between wood cribs, with a free distance corresponding to 15 m in large scale, was investigated. 相似文献