Particle fibers

Equation (1) points to a number of important particle properties. Clearly the particle diameter, by any definition, plays a role in the behavior of the particle. Two other particle properties, density and shape, are of significance. The shape becomes important if particles deviate significantly from sphericity. The majority of pharmaceutical aerosol particles exhibit a high level of rotational symmetry and consequently do not deviate substantially from spherical behavior. The notable exception is that of elongated particles, fibers, or needles, which exhibit shape factors, kp, substantially greater than 1. Density will frequently deviate from unity and must be considered in comparing aerodynamic and equivalent volume diameters. 

Put in ordinary terms, the more successful we are in causing a separation, the more propensities there are for a re-mixing of the components. There are many ways this can occur but there are a fewer number of important routes to mixing. It seems reasonable that we examine these before we consider all the possible ways in which thermodynamics can be controlled in general terms. In almost all equilibrium separation systems, the separation can occur either in a packed bed of particles or fibers or in an open channel or tube. The stationary phase is either coated on the walls of the channel or on the particles/fibers of the packed bed. If there were no mixing mechanisms an infinitely narrow packet containing the components would become a series of infinitely narrow packets of pure components moving at different velocities toward the end of the packed bed or tube. 

Although, the true density of solid phase p=m/Vp (e.g., g/cm3) is defined by an atomic-molecular structure (/ ), it has become fundamental to the definition of many texture parameters. In the case of porous solids, the volume of solid phase Vp is equal to the volume of all nonporous components (particles, fibers, etc.) of a PS. That is, Vp excludes all pores that may be present in the particles and the interparticular space. The PS shown in Figure 9.17a is formed from nonporous particles that form porous aggregates, which, in turn, form a macroscopic granule of a catalyst. In this case, the volume Vp is equal to the total volume of all nonporous primary particles, and the free volume between and inside the aggregates (secondary particles) is not included. 

Fillers can take many forms, including particles, fibers, flakes, and whiskers. Whiskers are individual crystals that act like tiny fibers. In the pleasure boat example, the glass, plastic, carbon, or other fiber constitutes the filler of the composite, and the plastic makes up the matrix. 

Fillers are available in many forms including particles, fibers, and mats or fabrics. Table 9.4 lists common forms of fillers and reinforcements that are used with epoxy adhesives. Note that epoxy adhesive film carriers such as fabrics or mats can be considered as a type of filler. 

Due to the need to check for particles, fibers, and possible discoloration in drug solutions transparent and colorless packaging materials are desirable. Hence, uncolored glass and plastic, bottles and bags, are commonly used as primary packaging for parenteral. To attain photo protection without losing VIS controllability, transparent containers or covers are necessary. 

For drugs which are soluble in SC CO2, the SC fluid can be expanded info air, or info a solufion containing polymers and other additives, such as phospholipids or Tween 80.1 By varying depressurization, the product can be formed as very fine particles, fibers, thin films, or as biodegradable polymeric microspheres containing drug. Typical biodegradable polymers which are soluble in the SC fluid include poly(hydroxyacid) and poly(D,L-lactic acid). Scale-up has been complicated... 

Necrosis of macrophage with the release of active factors, including the ingested particles/fibers... 

Figure 20.2. Sequential pattern of ceUular responses to inhaled particles/fibers.

Wettability - The rate at which a substance (particle, fiber) can be made wet under specified conditions. See also Wetting. 

In thermoplastics, the fillers and/or reinforcements can be in the form of particles, fibers or flakes. Fibers can be particularly effective since the flow patterns can create preferential orientation distributions and, therefore, directional properties. Table 10.36 shows typical properties of fibers, indicating the wide difference in strength and modulus compared to that of polymers. Glass fibers are typically 1-2 to 10-50 mm long, with an aspect ratio of 10-50. 

II. Metals cast or molded shapes powders or particles fibers... 

Uses Additive for ERP composites binder for loose particles/fibers sin-... 

Chem. Descrip. LDPE CAS 9002-88-4 EINECS/ELINCS 200-815-3 Uses Additive for FRP composites binder for loose particles/fibers sintering agent in ceramics, powd. metallurgy cosmetic filler for soaps/... 

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