Particle size selection

The effect of initial surfactant concentration was different according to the particle size of GACs (Fig. 4). In large particle size, selectivity was increased with increasing surfactant concentration unlike small particle size. This is because excess surfactant did not adsorb onto activated carbon due to small Ajx-... 

The classical approach for particle size determination, or more correctly for particle size selection - which is still used for solids like soils, sediments and other technical materials like coal, and also for biological materials - is sieving analysis. The raw material is milled, generally after drying, see Section 2.1, and if the required particle size is obtained, typically ranging from <0.1 to a few mm, it is allowed to pass sieves with different apertures to discard coarse particles and remaining materials. For materials consisting of numerous different particles microscopical inspection is used. 

Figure 10.1. A particle size selection guide to solid-solid separation techniques and equipment (after Roberts...

ACGIH (1985) Particle Size Selective Sampling in the Workplace, American Conference of Governmental Industrial Hygienists, Cincinnati, OH. 

This synergism of Group B-C mixtures testifies to the significance of particle size selection and particle size distribution design, in order to tailor a solid particulate material to certain desired fluidizing characteristics. 

Data collected for each run Included cation concentration using ICP and H concentration by titration. Filtering characteristics were determined using solid and liquid yield rates, as well as back pressures during the filtration cycle. The filter cake was characterized by moisture content and particle size. Selected samples of the cake were analyzed using SEM to determine average particle size and shape. 

Regarding the need for absolute removal of all free liquid mist, such as with a gas turbine compressor suction scrubber, I find a 100-pm particle size selection to be good design practice. This particle size fallout before reaching a demister pad will indeed ensure that most any demister pad will remove all remaining free liquid mist. 

The optimum conditions needed to achieve the desired sulfur capture efficiency (90 percent) is dependent on sorbent type, coal type, and fluidized bed design. Representative conditions are a bed temperature of 1116 K, a sorbent particle of 1 mm, and a Ca/S ratio of about 3. The bed temperature selection is based on the admittedly shaky evidence that this is where the maximum sulfation peaks. The particle size selection is a compromise between a desire to use high gas velocities and the observed decrease in sulfation with increasing size (Figure 2). The Ca/S ratio corresponds to a maximum sulfation of about 0.3. For these conditions the mass feed rate of a limestone sorbent is 0.345 that of the coal feed and the flow rate of the partially sulfated spent sorbent is 0.285 the coal feed rate. 

Regardless of the material combination, departures from conventional sputter deposition, such as cluster beam methods with particle size selection, shaping and heating capabilities independent of the substrate, may be necessary to achieve the desired granular microstructure [50-53]. 

Impact-mill Similar to jet-mill As above jet-mill As above Particle size selection possible... 

Finally, Chapter 12 describes initial studies on biological applications of porous SiC. Free-standing porous membranes are explored as particle-size-selective semi-permeable membranes for filtering of macro (bio-) molecules. SiC s hardness makes it chemically inert and bio-compatible... 

Particle size selective OEL have already been established to address the problems associated with specific health effects, especially within fields where solid aerosol particles are to be measured. A number of filter cassette designs have been tailored to sample specific size ranges of the total aerosol fraction, in order not to overestimate the exposure causing health effects by inhalation. Since only particles less than approximately 100 /rm can be inhaled and the inhaled aerosol fraction is most certainly the main contributor to specific health effects among workers exposed to isocyanates, it seems reasonable to use sampling devices designed for sampling of the inhalable... 

Corr D, Dolovich M, McCormack D, Ruffln R, Obminski G, Newhouse M. Design and characteristics of a protable breath actuated, particle size selective medical aerosol inhaler. 1 Aerosol Sci 1982 13 1-7. 

Several theories, however, have been proposed to serve as possible explanations for this complication. Small embolization particles administered within the uterine arteries can potentially make their way into the ovarian arterial circulation through patent uterine-to-ovarian anastomoses, increasing the risk of reduced ovarian perfusion and subsequent ischemia [6, 71]. This theory is supported by the demonstration of angiographically visible anastomoses between these two arterial beds in up to 10% of cases [71]. In addition, several reports described the presence of embolization particles in the ovarian arterial vasculature, within an oophorectomy specimen obtained after UFE [7, 72]. Microspheres smaller than 500 pm in diameter can pass within the ovarian arterial circulation after uterine artery embolization performed in sheep, which may offer some guidance as to particle size selection for this procedure [47]. 

Secondary clays are those clays, which have been transported away from their primary source to another location, where they have been deposited as a sediment. The transportation process was usually effective at both mineral separation and at particle size selection, in that only the finer particles remained in suspension long enough to reach the final deposit. Important secondary deposits are foimd in the kaolin belt of south-eastern United States (Alabama, through Georgia into South Carolina) and southwestern England. These clays are very fine with mean particle sizes from 0.1 to 2.0 pm. These are all semi-reinforcing fillers. 

The filler efficiency and the corresponding material endurance depend on many parameters. The filer type, the amount used, the particle size selected and the degree of bonding to the polymer matrix are some of them to be considered. In the case of ATH, which is the filler selected in many formulations, much research has been done in the direction of the optimum formulation that will conclude in an increased material performance and lifetime. 

Fig. 3 Evolution of Cr concentration (in weight %) in the bulk and in the oxide scales (thickness 1 and 1.5 /tm) as a function of particle size. Selected alloy has 22 wt % Cr...

Hinds WC. Basis for particle size-selective sampling for wood dust. Appl Ind Hyg 1988 3 67-72. 

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