共查询到20条相似文献,搜索用时 15 毫秒
1.
A macroscopic model of the process of magnetophoretic separation of slightly magnetic particles from a suspension under the
action of a high-gradient magnetic field with account for the particle size is proposed. The mechanisms of separation of dia-
and paramagnetic particles from a narrow fluid layer in an inhomogeneous field of a magnetized rod have been investigated.
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 82, No. 2, pp. 221–226, March–April, 2009. 相似文献
2.
3.
H. C. Greenwell L. M. L. Laurens R. J. Shields R. W. Lovitt K. J. Flynn 《Journal of the Royal Society Interface》2010,7(46):703-726
Microalgae provide various potential advantages for biofuel production when compared with ‘traditional’ crops. Specifically, large-scale microalgal culture need not compete for arable land, while in theory their productivity is greater. In consequence, there has been resurgence in interest and a proliferation of algae fuel projects. However, while on a theoretical basis, microalgae may produce between 10- and 100-fold more oil per acre, such capacities have not been validated on a commercial scale. We critically review current designs of algal culture facilities, including photobioreactors and open ponds, with regards to photosynthetic productivity and associated biomass and oil production and include an analysis of alternative approaches using models, balancing space needs, productivity and biomass concentrations, together with nutrient requirements. In the light of the current interest in synthetic genomics and genetic modifications, we also evaluate the options for potential metabolic engineering of the lipid biosynthesis pathways of microalgae. We conclude that although significant literature exists on microalgal growth and biochemistry, significantly more work needs to be undertaken to understand and potentially manipulate algal lipid metabolism. Furthermore, with regards to chemical upgrading of algal lipids and biomass, we describe alternative fuel synthesis routes, and discuss and evaluate the application of catalysts traditionally used for plant oils. Simulations that incorporate financial elements, along with fluid dynamics and algae growth models, are likely to be increasingly useful for predicting reactor design efficiency and life cycle analysis to determine the viability of the various options for large-scale culture. The greatest potential for cost reduction and increased yields most probably lies within closed or hybrid closed–open production systems. 相似文献
4.
5.
6.
7.
Magnetic cell separation has become a popular technique to enrich or deplete cells of interest from a heterogeneous cell population. One important aspect of magnetic cell separation is the degree to which a cell binds paramagnetic material. It is this paramagnetic material that imparts a positive magnetophoretic mobility to the target cell, thus allowing effective cell separation. A mathematical relationship has been developed to correlate magnetic labeling to the magnetophoretic mobility of an immunomagnetically labeled cell. Four parameters have been identified that significantly affect magnetophoretic mobility of an immunomagnetically labeled cell: the antibody binding capacity (ABC) of a cell population, the secondary antibody amplification (psi), the particle-magnetic field interaction parameter (DeltachiV(m)), and the cell diameter (D(c)). The ranges of these parameters are calculated and presented along with how the parameters affect the minimum and maximum range of magnetophoretic mobility. A detailed understanding of these parameters allows predictions of cellular magnetophoretic mobilities and provides control of cell mobility through selection of antibodies and magnetic particle conjugates. 相似文献
8.
High gradient magnetic separation has proved to be a successful method for removing micron size colouring bodies from china
clays. Clays from Chotanagpur, Bihar have been beneficiated to improve its brightness. The effect of field, flow rate and
dispersing agents has been studied on both the run of mine (rom) clay and the washed clay. Significant improvement in the
brightness of clay has been obtained. 相似文献
9.
10.
11.
12.
Ehresmann A Lengemann D Weis T Albrecht A Langfahl-Klabes J Göllner F Engel D 《Advanced materials (Deerfield Beach, Fla.)》2011,23(46):5568-5573
Domain wall movement assisted transport of particles: exchange-biased samples with designed stripe-domains show strong stray fields and an asymmetric magnetization reversal. Using these characteristics superparamagnetic particles can be trapped and transported directly on the sample over large-scale areas. High particle velocities, small external fields, and automatically reduced particle clustering allow broad applicability of this transport method. 相似文献
13.
Joo H. Kang Eujin Um Alexander Diaz Harry Driscoll Melissa J. Rodas Karel Domansky Alexander L. Watters Michael Super Howard A. Stone Donald E. Ingber 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(42):5657-5666
Magnetic nanoparticles have been employed to capture pathogens for many biological applications; however, optimal particle sizes have been determined empirically in specific capturing protocols. Here, a theoretical model that simulates capture of bacteria is described and used to calculate bacterial collision frequencies and magnetophoretic properties for a range of particle sizes. The model predicts that particles with a diameter of 460 nm should produce optimal separation of bacteria in buffer flowing at 1 L h−1. Validating the predictive power of the model, Staphylococcus aureus is separated from buffer and blood flowing through magnetic capture devices using six different sizes of magnetic particles. Experimental magnetic separation in buffer conditions confirms that particles with a diameter closest to the predicted optimal particle size provide the most effective capture. Modeling the capturing process in plasma and blood by introducing empirical constants (ce), which integrate the interfering effects of biological components on the binding kinetics of magnetic beads to bacteria, smaller beads with 50 nm diameters are predicted that exhibit maximum magnetic separation of bacteria from blood and experimentally validated this trend. The predictive power of the model suggests its utility for the future design of magnetic separation for diagnostic and therapeutic applications. 相似文献
14.
In order to evaluate the separation factor for the isotopic separation of Uranium in the conventional enrichment process by gaseous diffusion through membranes, it
is fundamental to control the size of the pore radius. The efficiency of the separation process depends critically on this
value. The existence of cracks may affect the perfomance of the membrane or even disable it. In the particular case of Uranium
enrichment, in order to increase the separation factor, it is necessary to have pores of a very small radius making even more
critical the presence of cracks. Here we discuss the influence of cracks on the separation process, deriving the corresponding
expressions for the separation factor (α) by considering its effect on the separation effectiveness (S) and the permeabi lity (H).
Received: 30 March 2000 相似文献
15.
16.
17.
以硝酸钴和硝酸铁为主要原料,采用化学共沉淀法制备CoFe2O4纳米磁性微粒,然后将其与膨胀石墨复合制得CoFe2O4载量不同的磁性膨胀石墨。用X射线衍射(XRD)、透射电镜(TEM)、震动样品磁强计(VSM)、扫描电镜(SEM)对CoFe2O4纳米磁性微粒和磁性膨胀石墨进行了表征。并研究了CoFe2O4载量不同的磁性膨胀石墨对不同油类的饱和吸油量、对水和油的竞争吸附比、不同吸附时间和环境温度对饱和吸油量的影响、磁分离回收及离心法再生吸附后的磁性膨胀石墨。结果表明,合成的CoFe2O4结晶度高,晶粒度约为13nm。CoFe2O4载量越低、油品粘度越高,磁性膨胀石墨的饱和吸油量越大;油品粘度越大,油、水竞争吸附时水含量越低;磁性膨胀石墨10s即可达到饱和吸油量的80%,90s后达到饱和吸附;CoFe2O4载量为35%时,磁回收率为99.2%,且再生离心转速为3000r/min时再生吸油量达到较大值。 相似文献
18.
19.
在多元醇媒介中采用溶剂热法合成了油酸/三苯基膦包裹的钴纳米粒子.采用X射线衍射4g(XRD)、透射电镜(TEM)、红外光谱仪(IR)和热重分析仪(TG)对所得样品进行了分析.TEM照片显示所制备的钴纳米粒子粒径约为14nm,分散良好,尺寸分布较窄.XRD分析表明,钴纳米以六角密堆积和面心立方的混晶形式存在.研究发现溶液的pH值对产物有重要影响,即只有当溶液的pH值高于12.62时才可以得到纯的纳米钴.热重分析证实包裹在纳米钴表面的油酸和三本基膦分别占整个纳米粒子质量的25.8%和69.2%. 相似文献
20.
Stefaan J. H. Soenen Nele Nuytten Simon F. De Meyer Stefaan C. De Smedt Marcel De Cuyper 《Small (Weinheim an der Bergstrasse, Germany)》2010,6(7):832-842
Iron oxide nanoparticle internalization exerts detrimental effects on cell physiology for a variety of particles, but little is known about the mechanism involved. The effects of high intracellular levels of four types of iron oxide particles (Resovist, Endorem, very small organic particles, and magnetoliposomes (MLs)) on the viability and physiology of murine C17.2 neural progenitor cells and human blood outgrowth endothelial cells are reported. The particles diminish cellular proliferation and affect the actin cytoskeleton and microtubule network architectures as well as focal adhesion formation and maturation. The extent of the effects correlates with the intracellular concentration (= iron mass) of the particles, with the biggest effects for Resovist and MLs at the highest concentration (1000 µg Fe mL?1). Similarly, the expression of focal adhesion kinase (FAK) and the amount of activated kinase (pY397‐FAK) are affected. The data suggest that high levels of perinuclear localized iron oxide nanoparticles diminish the efficiency of protein expression and sterically hinder the mature actin fibers, and could have detrimental effects on cell migration and differentiation. 相似文献