Fractionation, particulate

This approach is based on the premise that Al can be used as a tracer for bottom sediment material and that the concentration of Al in resus-pendable surface sediment is fairly uniform basinwide. Detailed profiles of size-fractionated particulate aluminum concentrations spaced closely in time over the unstratified period show vertical concentration profiles at nearly uniform levels, indicating that a pseudosteady state had been achieved. The mean areal pool of Al during this period was designated as the net resuspended pool (80-90% settles from the water column by September), and the quantity of surface sediment required to supply this pool was calculated. 

Perez L, Medina-Ramon M, Kiinzli N, Alastuey A, Pey J, Perez N, Garcia A, Tobias A, Querol X, Sunyer J (2009) Size fractionated particulate matter, vehicle traffic, and case specific daily mortality in Barcelona (Spain). Environ Sci Technol 43(13) 4707-4714. doi 10.1021/es8031488, 2009... 

Weinstein, S.E. and S.B. Moran. 2004. Distribution of size-fractionated particulate trace metals collected by bottles and in-situ pumps in the Gulf of Maine-Scotian Shelf and Labrador Sea. Mar. Chem. 87 121-135. 

To obtain the fractional particulate capture efficiency, E, of the power plant, divide the percentage of ash capmred by 100 ... 

PKC Carotid artery Cytosolic fraction Particulate fraction Singer et al. (1992)... 

Burnett RT, Goldberg MS (2003) Size fractionated particulate mass and daily mortality in 8 Canadian cities. In Health Effects Institute, special report. Revised analyses of time-series studies of air pollution and health, pp 85-89... 

Xiu, G., D. Zhang, J. Chen, X. Huang, Z. Chen, H. Guo and J. Pan (2004) Characterization of major water-soluble inorganic ions in size-fractionated particulate matters in Shanghai campus ambient air. Atmospheric Environment 38, 227-236 Yao, X., M. Fang and C. C. Chan (2003) The size dependence of chloride depletion in fine and coarse sea-salt particles. Atmospheric Environment 37, 743-751 Yokelson, R. I, T. Karl, P. Artaxo, D. R. Blake, T. J. Christian, D. W. T. Griffith, A. Guenther and W. M. Hao (2007) The tropical forest and fire emissions experiment Overview and airborne fire emission factor measurements. Atmospheric Chemistry and Physics Discussion 1, 6903-6958... 

Of the four commercial processes for the purification of carbon monoxide two processes are based on the absorption of carbon monoxide by salt solutions, the third uses either low temperature condensation or fractionation, and the fourth method utilizes the adsorption of carbon monoxide on a soHd adsorbent material. AH four processes use similar techniques to remove minor impurities. Particulates are removed in cyclones or by scmbbing. Scmbbing also removes any tars or heavy hydrocarbon fractions. Acid gases are removed by absorption in monoethanolamine, hot potassium carbonate, or by other patented removal processes. The purified gas stream is then sent to a carbon monoxide recovery section for final purification and by-product recovery. 

Sohd rocket propellants represent a very special case of a particulate composite ia which inorganic propellant particles, about 75% by volume, are bound ia an organic matrix such as polyurethane. An essential requirement is that the composite be uniform to promote a steady burning reaction (1). Further examples of particulate composites are those with metal matrices and iaclude cermets, which consist of ceramic particles ia a metal matrix, and dispersion hardened alloys, ia which the particles may be metal oxides or intermetallic compounds with smaller diameters and lower volume fractions than those ia cermets (1). The general nature of particulate reinforcement is such that the resulting composite material is macroscopicaHy isotropic. 

Creep Resistsince. Studies on creep resistance of particulate reinforced composites seem to indicate that such composites are less creep resistant than are monolithic matrices. Silicon nitride reinforced with 40 vol % TiN has been found to have a higher creep rate and a reduced creep strength compared to that of unreinforced silicon nitride. Further reduction in properties have been observed with an increase in the volume fraction of particles and a decrease in the particle size (20). Similar results have been found for SiC particulate reinforced silicon nitride (64). Poor creep behavior has been attributed to the presence of glassy phases in the composite, and removal of these from the microstmcture may improve the high temperature mechanical properties (64). 

Particulate Fluidization Fluid beds of Geldart class A powders that are operated at gas velocities above the minimum fluidizing velocity (L/, y) but belowthe minimum bubbhngvelocity (L/, i) are said to be particulately fluidized. As the gas velocity is increased above L/, y, the bed further expands. Decreasing (p, — Py), d and/or increasing increases the spread between L/, yand U, b until at some point, usually at high pressure, the bed is fully particulately fluidized. Richardson and Zald [Trans. Inst. Chem. Eng., 32, 35 (1954)] showed that U/U = E , where /i is a function of system properties, = void fraction, U = superficial fluid velocity, and Uj = theoretical superficial velocity from the Richardson and Zald plot when = 1. 

Leaching is the removal of a soluble fraction, in the form of a solution, from an insoluble, permeable sohd phase with which it is associated. The separation usually involves selective dissolution, with or without diffusion, but in the extreme case of simple washing it consists merely of the displacement (with some mixing) of one interstitial liquid by another with which it is miscible. The soluble constituent may be solid or liquid and it may be incorporated within, chemically combined with, adsorbed upon, or held mechanically in the pore structure of the insoluble material. The insoluble sohd may be massive and porous more often it is particulate, and the particles may be openly porous, cellular with selectively permeable cell walls, or surface-activated. 

Each is discussed in Sec. 17 of this handbook under Gas-Sohds Separations. The effectiveness of conventional air-poUution-control equipment for particulate removal is compared in Fig. 25-23. These fractional efficiency cui ves indicate that the equipment is least efficient in removing particulates in the 0.1- to 1.0- Im range. For wet... 

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