Particles granular

Granular media filtration is used for treating aqueous waste streams. The filter media consists of a bed of granular particles (typically sand or sand with anthracite or coal). The anthracite has adsorptive characteristics and hence can be beneficial in removing some biological and chemical contaminants in the wastewater. This material may also be substituted for activated charcoal. 

Messenger RNA (mRNA) carries genetic messages from DNA to ribosomes, small granular particles in the cytoplasm of a cell where protein synthesis takes place. 

The primary cellular function of mRNA is to direct biosynthesis of the thousands of diverse peptides and proteins required by an organism—perhaps 100,000 in a human. The mechanics of protein biosynthesis take place on ribosomes, small granular particles in the cytoplasm of a cell that consist of about 60% ribosomal RNA and 40% protein. 

Because PTFE cannot be dissolved or melted, there are problems with fabricating articles out of the polymer. These are overcome by using a technique similar to powder metallurgy, in which granular particles are fused under high pressures and temperatures. 

The earliest reports of controlled release steroids were those of Jackanicz (63), Yolles (64), Anderson (65), and Wise (66). Most of those early studies were based on poly[ (L+)-lactic acid). Implants and granular particles were fabricated with progesterone, norgestrel, and norethisterone. In vivo urinary excretion studies were conducted on [I Cjprogesterone beads (64). The reported results were somewhat questionable as only 20% of the original implanted drug could be accounted for. 

In order to avoid the problems of weak signals from typical solid samples, all NMR/MRI signals from granular particles to date have been obtained with solid particles containing liquids. The majority of experiments have been done either with seeds that naturally contain oils, predominantly mustard seeds, or pharmaceutical pills that contain liquid cores. In some cases, however, solid beads were impregnated with liquid to make them NMR-visible. In one case, it was oil-soaked sugar particles [12], while in another, acetone was imbibed into catalytic materials... 

Granular particles (100 to 150 Tyler mesh— equivalent diameter = 0.13 mm). 

Spherical pellets (1.27 cm diameter) fabricated by compressing unreduced granular particles in a steel mold. 

External mass transfer resistance was neglected, as reported by [63] in biofilm reactors with granular particles (fluidized bed, airlift) the Biot number was generally larger than 100. 

Sediment Type Wet Density x 103 (kg rrr3) % by Granular Particle Size (mm) Minimum-Mean-Maximum Organic Content (%)... 

In some cases the interaction between the particles and the surrounding fluid is of little significance, although at other times this can have a dominating effect on the behaviour of the system. Thus, in filtration or the flow of fluids through beds of granular particles, the characterisation of the porous mass as a whole is the principal feature, and the resistance to flow is dominated by the size and shape of the free space between the particles. In such situations, the particles are in physical contact with adjoining particles and there is... 

Buslik, D. Bull. Am. Soc. Testing Mat. 165 (1950) 66. Mixing and sampling with special reference to multisized granular particles. 

Fluidized-bed combustion is a process in which fuel or waste is burned in a turbulent bed of heated particles, normally sand, which is suspended (fluidized) by combustion air. A fluidized bed is a bed of granular particles through which a flow of gas passes upwards. The particles are suspended in the upwardly flowing stream and have the appearance of a boiling liquid. 

For granular particles, typical values of sphericity range between 0.6 and 0.95. In Table 3.13, the sphericity of selected materials is presented. 

For example, the most noteworthy disadvantage of catalytic wet oxidation is the severe catalyst deactivation (Larachi el al., 1999). Hamoudi el al. (1998, 1999) systematically studied the deactivation of Mn02/Ce02 catalyst during wet catalytic oxidation of phenol and the catalyst-surface modifications. It was observed that deactivation was induced mainly by the formation of carbonaceous deposits on the catalyst surface. Ohta et al. (1980) reported that the size of the catalyst particles affected the stabilization of catalytic activity. For granular particles of supported copper oxide, the catalytic activity was decreased after each inn, even after six successive experiments. In contrast, for larger particles the catalytic activity was stabilized after the first three runs. 

Before discussing the effects of pressure on biological activity it will be necessary to briefly review the behavior of powders or granules under applied pressure. Powder and granular particles tend to compact in three main stages. 

As manufactured, PTFE is of two principal types dispersion polymer, made by suspension polymerization followed by coagulation, and granular PTFE, polymerized and generally comminuted to a desirable particle size. Some details are given by Sperati. We have observed cast films of an aqueous colloidal dispersion and see that it consists of peanut-shaped particles, approximately 0.25 pm in size, which are composed of even finer particles. Electron micrographs of as-polymerized granular particles show three structures bands arranged in parallel, striated humps, and fibrils, some of which have the shish-kebab structure."... 

J. Li, D.J. Mason, A computational investigation of transient heat transfer in pneumatic transport of granular particles, Powder Technol. 112 (2000) 273-282. 

The structure of the interfacial layers in food colloids can be quite complex as these are usually comprised of mixtures of a variety of surfactants and all are probably at least partly adsorbed at interfaces which even individually, can form complex adsorption layers. The layers can be viscoelastic. Phospholipids form multi-lamellar structures at the interface and proteins, such as casein, can adsorb in a variety of conformations [78]. Lecithins not only adsorb also at interfaces, but can affect the conformations of adsorbed casein. The situation in food emulsions can be complicated further by the additional presence of solid particles. For example, the fat droplets in homogenized milk are surrounded by a membrane that contains phospholipid, protein and semi-solid casein micelles [78,816], Similarly, the oil droplets in mayonnaise are partly coated with granular particles formed from the phospho and lipo-protein components of egg yolk [78]. Finally, the phospholipids can also interact with proteins and lecithins to form independent vesicles [78], thus creating an additional dispersed phase. 

---