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41.
This bench-scale study investigated the passage of particle-associated bacteriophage through a dual-media (anthracite-sand) filter over a complete filter cycle and the effect on subsequent ultraviolet (UV) disinfection. Two model viruses, bacteriophages MS2 and T4, were considered. The water matrix was de-chlorinated tap water with either kaolin or Aldrich humic acid (AHA) added and coagulated with alum to form floc before filtration. The turbidity of the influent flocculated water was 6.4+/-1.5 NTU. Influent and filter effluent turbidity and particle counts were measured as well as headloss across the filter media. Filter effluent samples were collected for phage enumeration during three filter cycle stages: (i) filter ripening; (ii) stable operation; and (iii) end of filter cycle. Stable filter operation was defined according to a filter effluent turbidity goal of <0.3 NTU. Influent and filter effluent samples were subsequently exposed to UV light (254 nm) at 40 mJ/cm(2) using a low pressure UV collimated beam. The study found statistically significant differences (alpha=0.05) in the quantity of particle-associated phage present in the filter effluent during the three stages of filtration. There was reduced UV disinfection efficiency due to the presence of particle-associated phage in the filter effluent in trials with bacteriophage MS2 and humic acid floc. Unfiltered influent water samples also resulted in reduced UV inactivation of phage relative to particle-free control conditions for both phages. Trends in filter effluent turbidity corresponded with breakthrough of particle-associated phage in the filter effluent. The results therefore suggest that maintenance of optimum filtration conditions upstream of UV disinfection is a critical barrier to particle-associated viruses.  相似文献   
42.
Perrott  Ron Harmer  Terry Lewis  Rhys 《Computer》2008,41(11):67-72
Because digital media management and distribution technologies face some of the same challenges that e-Science aims to address, this technology is a viable solution to meet the broadcasting domain's rigorous demands.  相似文献   
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Partial homogenization using a microstructured SHM (Simultaneous Homogenizing and Mixing) valve significantly reduces aggregation of fat globules within their homogenization by feeding the continuous phase directly into the droplet disruption zone (as discussed in part I of this work). It allows homogenization of cream containing up to at least 42 vol.‐% fat, and thus, significantly reduces processing costs without loss in product quality, i.e., overall process intensification. The present article details current results on the influence of material parameters, i.e., emulsifier system and fat content, and process parameters, i.e., homogenizing pressure and the temperature of both streams, on the fat globule size distribution. In contrast to conventional technology, SHM valve technology generates decreasing droplet sizes with increasing pressure or with increasing temperature of the homogenizing stream. This novel technique breaks new ground in dairy product design.  相似文献   
46.
天然裂缝性储层的特征   总被引:2,自引:0,他引:2  
天然裂缝性储层给开采带来了一个矛盾难题。这类储层包括低油气采收率储层,这些储层最初可能表现出高产,但产能下降得非常快。此外,这类储层还经常出现早期见气或见水等问题。而另一方面,一些天然裂缝性储层也是全球最大、产量最高的储层。这类储层的这种矛盾特性激发业界尽力去深入了解其特征,以便更有把握地对其进行模拟分析。  相似文献   
47.
带服务能够支持三重应用(即支持语音、视频和数据)至第一英里的客户,例如持续发展的小商业和住宅。FTTx中的主角是GPON(吉比特无源光网络,Gigabit Passive Optical Network),它提供较高的带宽替代DSL和电缆的基于光纤的网络。FTTx为家庭的第一英里应用,诸如光纤到户(FTTH),  相似文献   
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橡胶是一种有粘性的材料,其粘性有利于把不同橡胶部件成型在一起,但也会引起一些严重的问题。  相似文献   
49.
Southwire continuous rod technology has been used for approximately a quarter of a century to produce high-quality copper rod, and ongoing modifications to the process have improved not only the copper product, but the actual efficiency of the production system. Some of these developments have been achieved through automatic quality monitoring and the application of sophisticated control devices.  相似文献   
50.
Weanling male spontaneously hypertensive (SHR) and normotensive (WKY) rats were maintained on a fat-free semisynthetic diet and killed at various intervals. The effects of fat-depletion on the appearance of essential fatty acid (EFA) deficiency symptoms, the progressive changes of major fatty acids in plasma, liver, heart, and kidney phospholipids (PL), and in skin total lipids were compared between these two strains. After five weeks on the diet, the slower growth and the appearance of EFA deficiency symptoms became evident in SHR. In general, fat-depletion reduced the levels of n−6 fatty acids, whereas it increased those of 20∶3n−9. However, the fat-depletion induced reduction of 18∶2n−6 in heart PL and 20∶4n−6 in kidney, while the elevation of 20∶3n−9 in plasma, heart, and kidney PL were greater in WKY than in SHR. As a result, the elevation of biochemical EFA deficiency index—20∶3n−9/20∶4n−6 ratio—was greater in WKY than in SHR. In comparison with WKY, the concentrations of liver triacylglycerols and the weights of adipose tissues in SHR were reduced to a greater extent, indicating an active catabolism of triacylglycerols in SHR. This study suggests that the earlier appearance of morphological symptoms of EFA deficiency in SHR was not associated with the reducing n−6 EFA levels or with an elevation of triene/tetraene ratio, but possibly to a reduced supply of n−6 EFA for skin prostaglandin synthesis.  相似文献   
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