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排序方式: 共有148条查询结果,搜索用时 15 毫秒
141.
为了研究消防水幕衰减火灾热辐射和阻隔火灾烟气蔓延的隔热阻烟特性,基于搭建的3 m× 3 m × 2.5 m(长×宽×高)小尺寸试验平台,开展大量实体火灾试验,研究水幕作用下空间温度分布特性以及烟气运动规律,并重点分析了喷头压力和喷头类型2种参数对水幕隔热阻烟性能的影响。结果表明:实施水幕分隔对火灾上层高温烟气具有明显的降温作用;实施水幕能够有效阻止火灾烟气的前期扩散;喷头压力越大,水幕的隔热效率越高,当喷头压力增大至0.6 MPa时,水幕的隔热效率可达70%以上;使用ZSTWC撞击式水雾喷头比ZSTM-AT式扇形水幕喷头更有利于形成均匀分布的水幕断面。 相似文献
142.
废冰箱保温材料低温热解及气体成分分析 总被引:4,自引:3,他引:1
在80~220 ℃内,通过热重分析仪-傅立叶变化红外线光谱(TGA-FTIR)联用研究半球牌和雪花牌冰箱保温材料(聚氨酯硬质泡沫,简称PUR泡沫)热解特性.结果表明,PUR泡沫的质量损失随温度的增加而快速增大. 80~160 ℃的主要气体化合物有多元醇、氟氯化碳化合物 (CFCs)和含氯烷烃,并未发生热分解;170~220 ℃时发生初始热分解,主要是聚合物主链上的C—O键发生断裂,分解成多异氰酸酯和多元醇,同时还有烯烃产生. 在160 ℃以下加热PUR泡沫可快速移除包裹和吸附于泡沫中的CFCs,但在加热期间,必须收集和处理CFCs. 相似文献
143.
144.
城市宾馆的噪声控制状况普遍不佳。针对目前这种情况,宾馆在选址及总平面布置方面应作周密考虑,尤其要注意客房的单体设计及相应的建筑隔声处理,包括朝向、间距和围护结构(如门窗、走廊)等相关问题。 相似文献
145.
针对国内现有的外墙外保温系统的防火性较差的现状,通过分析上海公寓楼外墙保温层的火灾,得到外墙外保温防火的三种重要因素(粘结或固定方式、防火隔离带的构造、防火保护面层)。鉴于现在流行的保温材料为膨胀聚苯板(EPS),因而选用EPS作为模拟材料,利用数值模拟计算得出以下结论:认为火灾时有空腔的保温层比无空腔的保温层更危险;设置防火隔离带能有效得阻隔火灾的蔓延,较宽的隔离带效果更好。除此之外,外保温层防火设计中还应考虑以下三方面的问题,即遴选适当的保温材料、建议保温层也使用类似于防火分区的防火措施和保证保温效果的同时增加防火隔离带的宽度。研究结论和建议对于解决外墙保温体系防火问题具有重要的参考价值和现实意义。 相似文献
146.
《International Journal of Sustainable Engineering》2013,6(3):266-280
Cost-effective materials, products and installation methods are required to improve the energy efficiency of the UK's existing building stock. The aim of this paper is to assess the potential for high-performance translucent granular aerogel insulation to be retrofitted over single glazing to reduce heat loss without blocking out all of the useful natural light. In situ testing of a 10-mm-thick prototype panel, consisting of a clear twin-wall polycarbonate sheet filled with granular aerogel, was carried out and validated with steady-state calculations. Results demonstrate that an 80% reduction in heat loss can be achieved without detrimental reductions in light transmission. Payback calculations accounting for the inevitable thermal bridging from openable solutions such as roller shutters or pop-in secondary glazing suggest that a return on investment between 3.5 and 9.5 years is possible if products are consistently used over the heating season. Granular aerogel is a promising material for improving the thermal performance of existing windows. Future research will seek to map out different ways in which the material can be applied to the existing UK housing stock, identifying which systems offer the greatest potential for widespread CO2 savings over their life cycle. 相似文献
147.
Material selection in manufacturing may be characterized as a series of trade-offs between characteristics, properties, environmental impacts, sustainability, availability, and economics. Societal concerns about the environmental impacts of construction practices and materials have been expressed through an increase in the demand, production and use of “green” building products. This, combined with a desire to integrate more bioproducts and natural and renewable resources into the construction industry, has extended to the production and promotion of insulation made from sheep's wool.Although substantial literature exists on the insulation properties and other benefits of wool, less is known about the economics and manufacturing processes of sheep's wool insulation at varying scales of production. This paper contributes to this field of enquiry through presentation of the preliminary results of a wool insulation manufacturing pilot project, in which the scale and economics of the production of sheep's wool insulation were considered. Processing techniques, the impact of sheep breed, yield, energy use, and manufacturing costs were also examined. The results of the pilot project indicate that, while sheep's wool insulation produced at a smaller, or artisanal scale shows some potential, scale of operation and volume of production need to be carefully considered in order to ensure long-term sustainability of the operation. Using the least expensive sheep's wool available for the manufacture of wool batt insulation (and thereby reducing production costs) did not, in this pilot study, have a negative impact on productivity or product performance. Diversion of this waste stream of currently less marketable, and consequently less valuable wool, into the production of a green building material may offer small but significant benefit to sheep producers and the broader agricultural community, as well as consumers. 相似文献
148.
为增强木材的阻燃性能,采用压缩致密化工艺制备致密化阻燃木材,并对其燃烧特性与成炭行为进行研究。结果表明:压缩致密化工艺能促进木材在燃烧过程中形成更多的芳香结构以增强炭层的致密性和隔热性,进而有效阻隔热量和氧气进入木材内部,使致密化木材表现出良好的阻燃性和自熄性。压缩致密化木材的阻燃和隔热性能与去木质化程度密切相关,并随去木质化程度的增加呈先提高后下降的趋势。经过24 h去木质素处理后的致密化木材的极限氧指数增加到39.5%并达到UL94 V-0级,总释放热和2 400 s背面平衡温度相比于未去木质素的致密化木材分别下降了25.8%和21.4%,表现出最佳的阻燃和隔热性能。 相似文献