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61.
Low energy ballasted flotation   总被引:1,自引:0,他引:1  
P. Jarvis  B. Holden 《Water research》2009,43(14):3427-3434
A novel process which involves the replacement or supplementation of bubbles in the dissolved air flotation process with low density beads is presented. The work comprised a series of bench-scale flotation trials treating three commonly encountered algal species (Microcystis, Melosira and Chlorella) that were removed in a flotation cell configured as either: conventional dissolved air flotation (DAF); ballasted flotation using low density 70 μm glass beads with a density of 100 kg m−3; or a hybrid process of ballasted flotation combined with conventional DAF. Results indicated that the bead only system was capable of achieving better residual turbidity than standard DAF at bead concentrations of 500 mg L−1. Addition of beads in combination with standard DAF reduced turbidity further to even lower residual turbidity levels. Algae removal was improved when glass beads were dosed, but removal was dependent on algal species. Microcystis was removed by 97% for bead only systems and this removal did not change significantly with the addition of air bubbles. Melosira was the next best removed algae with bead only dosed systems giving similar removals to that achieved by standard DAF using a 10% air recycle ratio (81 and 76% removal respectively). Chlorella was the least well removed algae by bead only systems (63% removal). However, removal was rapidly improved to 86% by the addition of air bubbles using only a 2% recycle ratio. Energy estimations suggested that at least a 50% energy reduction could be achieved using the process offering a potential route for future development of low energy separation processes for algae removal.  相似文献   
62.
Professional geropsychology is a growing area of practice and training. To meet the mental health needs of an aging population, increasing numbers of psychologists need to develop competence to work with older adults, their families, and related care systems. The Pikes Peak model for geropsychology training (Knight, Karel, Hinrichsen, Qualls, & Duffy, 2009) delineates attitude, knowledge, and skill competencies for professional geropsychology practice and makes recommendations for training. In this paper, we define and illustrate the Pikes Peak geropsychology practice competencies through a case example. In the case, an older man with complex needs seeks care through a generalist psychologist in an outpatient setting. The attitudes, knowledge, and skills that the psychologist needs to consider, and implications for training, are reviewed. Training recommendations and resources are provided, with a focus on the training needs of psychologists who wish to expand their practices to include older adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
63.
64.
对于完整的控制和安全系统,建立强大的防护体系是否是一项可以确保安全仪表系统商业连续性的必要投资?  相似文献   
65.
创新推动无线技术的发展,成功的应用充分证明无线技术的经济、可靠、安全和易用性。  相似文献   
66.
传感器对工业系统设计中的性能、可靠性、安全性和自身成本等方面具有提供重大改进的潜能.涉及惯性传感器的应用案例包括平台稳定性、工业机器的运动控制、安全性设备、天线稳定性、机器人技术、导航、机械调平以及许多其它的应用.但是,在优秀的传感器技术与其在重要工业系统中的实现之间长期以来一直处于空白阶段.  相似文献   
67.
In this research, a number of process modifications to the lime-soda softening process were examined, including utilization of high Mg-content lime, addition of MgCl2, and the recycling of softening sludge, in order to improve the removal of natural organic matter (NOM) and reduce the formation of disinfection byproducts (DBPs). Jar test results showed that dissolved organic carbon (DOC) removal increased and trihalomethane (THM) formation was reduced as the magnesium in hydrated lime increased, and was directly correlated with the amount of magnesium removed from the system. However, a dolomitic quick lime hydrated under atmospheric conditions resulted in less effective DOC removal due to a lack of available Mg, and subsequently, less co-precipitation of Mg(OH)2-NOM complexes. The addition of MgCl2 to the raw water also increased DOC removal and reduced THM formation in both the presence and absence of softening sludge, with DOC removal increasing as softening sludge and magnesium dosages increased. As high as 43% removal of DOC was achieved at the stoichoimetric lime-soda ash dose in the presence of 457 mg/L sludge and 7.5 mg/L MgCl2, as compared to only 13% removal in the absence of sludge and MgCl2. The recycling of softening sludge had little or no effect on the hardness and the level of inorganic elements in treated water. The results presented here provide new approaches for improving DBP precursor removal during lime-soda softening without significantly increasing lime and soda ash dosage or the generation of waste sludge.  相似文献   
68.
We searched for new components that are involved in the positive regulation of nuclear gene expression by light by extending a screen for Arabidopsis cue (chlorophyll a/b-binding [CAB] protein-underexpressed) mutants (H.-M. Li, K. Culligan, R.A. Dixon, J. Chory [1995] Plant Cell 7: 1599-1610). cue mutants display reduced expression of the CAB3 gene, which encodes light-harvesting chlorophyll protein, the main chloroplast antenna. The new mutants can be divided into (a) phytochrome-deficient mutants (hy1 and phyB), (b) virescent or delayed-greening mutants (cue3, cue6, and cue8), and (c) uniformly pale mutants (cue4 and cue9). For each of the mutants, the reduction in CAB expression correlates with the visible phenotype, defective chloroplast development, and reduced abundance of the light-harvesting chlorophyll protein. Levels of protochlorophyllide oxidoreductase (POR) were reduced to varying degrees in etiolated mutant seedlings. In the dark, whereas the virescent mutants displayed reduced CAB expression and the lowest levels of POR protein, the other mutants expressed CAB and accumulated POR at near wild-type levels. All of the mutants, with the exception of cue6, were compromised in their ability to derepress CAB expression in response to phytochrome activation. Based on these results, we propose that the previously postulated plastid-derived signal is closely involved in the pathway through which phytochrome regulates the expression of nuclear genes encoding plastid proteins.  相似文献   
69.
A field study of soils and pistachio nuts in three major pistachio-growing areas of Turkey has been undertaken. The predominant soil fungus isolated from all three areas was Aspergillus niger; isolates of Fusarium, Trichoderma, Mucor and Rhizopus species were also common. A flavus and A. ochraceus and related organisms were isolated only from the plateau of Gaziantep. The dominant external mycoflora of the immature nuts from all sites consisted of A. niger, A. flavus and Penicillium spp. There was no evidence for fungal contamination of immature endosperms nor of freshly dehulled nuts, but stored dehulled nuts and dust samples taken from ware-houses were extensively contaminated with A. flavus, A. niger and A. ochraceus. Of 43 A. flavus isolates tested, 20 produced aflatoxins on laboratory media or on rice; all 11 isolates of A. ochraceus tested produced ochratoxin A on laboratory media. The results obtained are discussed in relation to agricultural and marketing practices for Turkish pistachio nuts.  相似文献   
70.
N6-(p-Azidobenzyl)adenosine (ABA) and nitrobenzylthioinosine (NBMPR) were employed as covalent probes of the nucleoside transport mechanism in human erythrocytes. NBMPR, a potent inhibitor of nucleoside transport, binds tightly (KD 0.3-1 nM) to specific sites on nucleoside transporter elements. ABA, a less potent inhibitor of uridine influx, competitively inhibited NBMPR binding (Ki 15 nM). [3H]ABA was bound tightly (KD 13.4 nM) but reversibly to sites on erythrocytes which appeared to be those which bind NBMPR. ABA binding was inhibited by uridine and adenosine. Irradiation with UV light caused site-bound [3H]ABA on erythrocyte membranes to become covalently bound and, similarly, photoactivation resulted in covalent attachment of membrane-bound [3H]NBMPR. In the presence of dithiothreitol, a free radical scavenger, photoactivation of the site-bound 3H-ligand on membranes depleted of extrinsic membrane proteins resulted in selective incorporation of 3H into band 4.5 of the membrane polypeptides which were resolved on sodium dodecyl sulfate-polyacrylamide gel electropherograms. This result, when considered with previous findings, indicates that the NBMPR-binding component of the nucleoside transport mechanism (or the entire mechanism, if the NBMPR site is an integral part) is a band 4.5 polypeptide.  相似文献   
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