LPG储罐的失效原因分析

简要介绍了LPG储罐的各种失效形式及其特征,分析了导致储罐失效的主要原因,用事故树分析方法进行整理归纳,并针对各种失效形式分别提出防治措施.     

火灾环境中LPG储罐失效的研究

分别从实验和数值模拟研究两个方面对火灾环境中LPG储罐的失效进行探讨,简要介绍了近年来国内外研究现状和研究成果.从储罐内部和外部环境两个方面的因素,对火灾环境中LPG储罐失效的原因进行了简单分析.提出了今后的研究发展方向.     

污水稳定塘菌-藻生态系统去除与灭活植物病毒TMV研究

了解污水稳定塘生态系统去除与灭活植物病毒的效率与机理具有重要的理论和实际意义。 对模型植物病毒———烟草花叶病毒(tobaccomosaicvirus, TMV)的实验结果显示:稳定塘系统中的悬浮固体(SS)可在短时间内吸附TMV且达到一个饱和值。 纯培养的枯草芽孢杆菌及小球藻对TMV的存活无明显不良影响, 而光合细菌和稳定塘中的混合细菌群却对TMV具有灭活作用。 当它们同藻类形成菌藻共生体系时, 对TMV的灭活速率分别从对照的每天0.0404log10(枯斑数·mL-1)升高到0.     

Virus transport in physically and geochemically heterogeneous subsurface porous media

A two-dimensional model for virus transport in physically and geochemically heterogeneous subsurface porous media is presented. The model involves solution of the advection-dispersion equation, which additionally considers virus inactivation in the solution, as well as virus removal at the solid matrix surface due to attachment (deposition), release, and inactivation. Two surface inactivation models for the fate of attached inactive viruses and their subsequent role on virus attachment and release were considered. Geochemical heterogeneity, portrayed as patches of positively charged metal oxyhydroxide coatings on collector grain surfaces, and physical heterogeneity, portrayed as spatial variability of hydraulic conductivity, were incorporated in the model. Both layered and randomly (log-normally) distributed physical and geochemical heterogeneities were considered. The upstream weighted multiple cell balance method was employed to numerically solve the governing equations of groundwater flow and virus transport. Model predictions show that the presence of subsurface layered geochemical and physical heterogeneity results in preferential flow paths and thus significantly affect virus mobility. Random distributions of physical and geochemical heterogeneity have also notable influence on the virus transport behavior. While the solution inactivation rate was found to significantly influence the virus transport behavior, surface inactivation under realistic field conditions has probably a negligible influence on the overall virus transport. It was further demonstrated that large virus release rates result in extended periods of virus breakthrough over significant distances downstream from the injection sites. This behavior suggests that simpler models that account for virus adsorption through a retardation factor may yield a misleading assessment of virus transport in "hydrogeologically sensitive" subsurface environments.     

鼠伤寒沙门氏菌的紫外灭活及光复活抑制的研究

研究了鼠伤寒沙门氏菌的紫外失活动力学、在日光灯下的光复活现象以及氯对其光复活的抑制。结果表明,鼠伤寒沙门氏菌的紫外失活动力学曲线分为滞后区、一级动力学区、拖尾区三阶段,在PBS中的一级动力学失活速率常数为0.9041 cm2/mJ。而紫外灭活后的鼠伤寒沙门氏菌在日光灯下存在光复活。当紫外剂量为10 mJ/cm2时,鼠伤寒沙门氏菌在日光灯下照射3 h内发生明显的光复活,浓度从8.6×103CFU/mL增加到4.1×106 CFU/mL;但是在紫外消毒后,投加1 mg/L的氯可以有效抑制该细菌的光复活,投加2 mg/L的氯可以在10 min内全部灭活。因此,紫外-氯联合消毒能够有效的抑制鼠伤寒沙门氏菌细菌光复活,使其得到高效灭活。     

固载型TiO2光催化反应器对富营养水体杀藻作用研究

以泡沫镍作为载体,利用电沉积技术将纳米TiO2负载在泡沫镍上,制成固载型TiO2光催化反应器。研究表明,经过光催化反应器处理的富营养水体,30 h内叶绿素a由96.2 mg/m3降至2.2mg/m3,下降率达97.6％,而未负载纳米TiO2普通泡沫镍材料,在同样光强的紫外灯照射下,叶绿素a下降率为74.3％,表明紫外光照射虽然也具有一定的杀藻功能,但是光催化反应才是藻类被杀灭的主要原因。利用9.54 m3景观喷水池进行杀藻中试,光催化反应器也同样表现出优异的杀藻性能,12 d内叶绿素a由18.7 mg/m3降至1.9mg/m3,下降率达到89.8％,水体由浓绿变为清澈见底,这表明光催化反应器具有很强的杀藻能力,通过有效杀灭富营养水体中藻类、控制藻类基数,对应急处理城市景观水、湖泊等富营养水体和突发性藻华,提高生物-生态法处理效率,改善城市水环境具有十分重要的意义。     

H2O2氧化铜绿微囊藻致嗅物质及灭藻效应研究

分别以不同浓度梯度的H_2O_2为氧化剂,研究其对铜绿微囊藻致嗅物质β-环柠檬醛的去除效果和藻细胞的灭活程度.结果表明,当藻细胞密度为1.01×10~6cells·m L~(-1)时,H_2O_2对胞外β-环柠檬醛的氧化较为迅速,反应1 min内即可去除75%以上,而对胞内β-环柠檬醛的降解比较缓慢,只有在投加4或5 mg·L~(-1)时才能取得显著效果;其降解的二级动力学速率常数为57.12 L·mol~(-1)·s~(-1);H_2O_2的氧化能力相对较弱,不足以导致藻细胞剧烈破碎,但也因此而减少了藻毒素的释放;并且H_2O_2可使溶解性有机物各个组分的荧光强度明显降低,荧光峰中心位置也发生了一定的偏移;因细胞壁和细胞膜受到损害,浓度为4 mg·L~(-1)以上的H_2O_2能够充分灭活藻细胞.