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901.
Niansheng KuaiJianming Li Zhi ChenWeixing Huang Jingjie YuanWenqing Xu 《Journal of Loss Prevention in the Process Industries》2011,24(4):302-313
An experimental investigation was carried out on magnesium dust explosions. Tests of explosion severity, flammability limit and solid inerting were conducted thanks to the Siwek 20 L vessel and influences of dust concentration, particle size, ignition energy, initial pressure and added inertant were taken into account. That magnesium dust is more of an explosion hazard than coal dust is confirmed and quantified by contrastive investigation. The Chinese procedure GB/T 16425 is overly conservative for LEL determination while EN 14034-3 yields realistic LEL data. It is also suggested that 2000-5000 J is the most appropriate ignition energy to use in the LEL determination of magnesium dusts, using the 20 L vessel. It is essential to point out that the overdriving phenomenon usually occurs for carbonaceous and less volatile metal materials is not notable for magnesium dusts. Trends of faster burning velocity and more efficient and adiabatic flame propagation are associated with fuel-rich dust clouds, smaller particles and hyperbaric conditions. Moreover, Inerting effectiveness of CaCO3 appears to be higher than KCl values on thermodynamics, whereas KCl represents higher effectiveness upon kinetics. Finer inertant shows better inerting effectiveness. 相似文献
902.
Yasuhiro Sugimoto Daisuke Tashima Yoki Asano 《Process Safety and Environmental Protection》2011,89(5):323-326
We developed a new system for collecting electrons generated by bacterial activity to supply DC (direct current) electrical energy. This system used eight titanium sub-electrodes (surface area of each sub-electrode: 189 cm2) connected to one central main titanium electrode (surface area of electrode: 1571 cm2). The distance between each sub-electrode and the main electrode was 30 cm. In an initial experiment, we collected electrons during composting cattle excreta, which was mixed with a commercially available microbial compost activator/starter. We analysed the relationships between the composting temperature and electrical current and voltage. Electrons were effectively collected and used successfully to obtain DC electrical energy. Generation of a stable voltage of approximately 0.5 V was clearly observed. This voltage was not related to compost temperature; however, the generated electrical current increased and decreased with compost temperature. The method was then used in a second experiment to collect electrons generated by bacterial activity in an agricultural field (area: 48 m2). Electrons in the field were effectively collected, and we measured a stable voltage of approximately 1.1 V and a stable current of approximately 0.7 mA. The system has the advantages of being simple, easily maintained, inexpensive, and applicable to large-scale agricultural fields. 相似文献
903.
Rivers crossing coastal plains are often inefficient conveyors of sediment, so that changes in upstream sediment dynamics are not evident at the river mouth. Extensive accommodation space and low stream power often result in extensive alluvial storage upstream of estuaries and correspondingly low sediment loads at the river mouth. However, gaging stations with sediment records are typically well upstream of the coast, and thus tend to overestimate sediment yields by under-representing the lower coastal plain and because there is often a net loss of sediment in lower coastal plain reaches. Studies of alluvial sediment storage have generally focused on accommodation space, but, using examples from Texas, we show that low transport capacity controlled largely by slope is a crucial factor. 相似文献
904.
企业清洁生产审核是企业实行清洁生产的重要前提.阐明了企业清洁生产审核的重要性、面临的形式、存在的问题,以及改进的措施和努力的方向. 相似文献
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秦皇岛市在新能源的开发利用方面做了大量工作,但是在政策、产业和技术等方面仍需要进一步加强建设:调整新能源发展思路,制定新能源发展规划,围绕电价、税收等制定政策,并建立新能源基金,加强新能源利用技术产品的开发;做大做强新能源龙头企业,建设新能源示范工程和生态工业园区,开展技术创新,实施人才引进与培养工程,进行国际化运作。 相似文献
910.
1954年12月26日-1955年1月18日湖北省遭遇了120年一遇的历史罕见持续低温冰雪灾害。2008年1月13日-2月3日,湖北省再次出现了一次持续低温冰雪过程,严重程度仅次于1954年,为70年一遇。利用常规天气图和数值预报产品资料,应用天气学和波谱分析方法,对比分析了两次过程的环流形势特征及能谱特征。结果表明:两次过程具有基本一致的长波系统背景场、水汽条件、地面冷空气条件;在低温冰雪过程中,850~700hPa存在明显逆温层;中高纬度、中低纬度能量谱强度、输送和转换有明显的变化,并且与天气系统的变化相对应。但是,两次天气过程的表现形式有明显差异,而且前者的主要影响系统,如阻塞高压、低涡、副高和地面冷高压等的强度均明显比后者强。 相似文献