Materials pellets

Image analysis in case of size change in organic material, pellets, mycelium hyphae or agglomerates of single cells (see e.g. [44 - 54,60])... 

In this example, the composition of the catalyst surface is responsible for its activity. Therefore, catalysts are placed on porous supporting material (pellets) which have specific surface areas of some hundred m2/g pellet. Because the pellet core has the largest surface area, the reaction predominantely takes place here. 

The probability of readsorption increases as the intrinsic readsorption reactivity of a-olefins (k,) increases and as their effective residence time within catalyst pores and bed interstices increases. The Thiele modulus [Eq. (15)] contains a parameter that contains only structural properties of the support material ( <>, pellet radius Fp, pore radius 4>, porosity) and the density of Ru or Co sites (0m) on the support surface. A similar dimensional analysis of Eqs. (l9)-(24), which describe reactant transport during FT synthesis, shows that a similar structural parameter governs intrapellet concentration gradients of CO and H2 [Eq. (25)]. In this case, the first term in the Thiele modulus (i/>co) reflects the reactive and diffusive properties of CO and H2 and the second term ( ) accounts for the effect of catalyst structure on reactant transport limitations. Not surprisingly, this second term is... 

Fiberfill molding (Fiberfil ). A term used for an injection-molding process employing as a molding material pellets containing short bundles of fiber surrounded by resin. 

Roller compactors are available in different designs and can be equipped with a variety of differently profiled rollers to produce compacted material, pellets, or briquettes. Usually, the compacted product then has to be milled to the desired particle size. To minimize dust and fines, which have to be recycled back to the compaction process, selection of suitable milling equipment is important. Gentle systems, such as roller mills or sieve mills, are preferred. As Figure 16.21 shows, compacted granules appear as more irregular, sharp-edged particles. 

Phase change material pellets consist of a tnixmre of paraffin (n-octadecane), a polymer, and a thermal conductivity improver (expandable graphite, graphite microfiber pieces, or graphite powder), a nucleating agent (sodium and calcium chloride and 1-octa-decanol). ... 

A partial list of the tool-kit available for nuclear forensics investigations is shown in Table 5.1 (IAEA 2006). A somewhat different list of the tools that are used to characterize seized nuclear materials (pellets or powder) is shown in Table 5.2 (Wallenius et al. 2006). One more point that is almost unique for nuclear forensics when a smuggled radioactive material is seized or when undeclared nuclear activities are suspected, the law enforcement forces are expected to provide a preliminary characterization of the material within a short time (usually 24 h) and more detailed and accurate data after a few more days, as shown in Table 5.3 (IAEA 2006). These publications will be mentioned in context with the subject matter of this chapter. 

Color concentrates are also used for some materials. Pellets of plastic containing high concentration of color are mixed with the clear pellets in a ratio of about 1 10 for plunger machines and 1 20 for screw machines. The correct shade and intensity of color is ascertained by experimenting with the amounts of colorant used and the length of tumbling time. ... 

Historically, hard tissues were analyzed by FT-IR as homogenized powders in KBr or other infrared transparent material pellets of known sample concentrations. 

A major difference between spinning methods is in how the raw material (pellets or powder) is liquefied. 

Polymer reactions have another attribute that can have a significant effect on processing. Some polymers are delivered in a form in which the polymerizalion reaction is essentially complete. They are described by the broad term thermoplastics. Thermoplastic materials are converted to parts through the application of heat and force. They are normally delivered as solid materials (pellets, powders, or granules) and are melted by the process and cooled to solidification to produce their finished part fonn. Polymer materials that can be handled in this way are often referred to as being melt processable. One of the chief advantages of thermoplastics is that they can be remelted and used more than once (within limitations) by the processor. 

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