Particles capsule

The capsules are separated from the process liquid by filtering (Figure 11-8). The filter uses a medium a flat material with little holes. Surprisingly the holes are usually chosen larger than the particles (capsules) to be retained. If the pores are not too large, particles form bridges... 

Microencapsulation Processes with Their Relative Particle Size Ranges Approximate Particle/Capsule Size (pm) Approximate Payload% ... 

Development of other polymer-based ERMs (self-immolative polymers, micelles, solid particles, capsules)... 

In addition to graft copolymer attached to the mbber particle surface, the formation of styrene—acrylonitrile copolymer occluded within the mbber particle may occur. The mechanism and extent of occluded polymer formation depends on the manufacturing process. The factors affecting occlusion formation in bulk (77) and emulsion processes (78) have been described. The use of block copolymers of styrene and butadiene in bulk systems can control particle size and give rise to unusual particle morphologies (eg, coil, rod, capsule, cellular) (77). 

The extremely high peak power densities available ia particle beams and lasers can heat the small amounts of matter ia the fuel capsules to the temperatures required for fusion. In order to attain such temperatures, however, the mass of the fuel capsules must be kept quite low. As a result, the capsules are quite small. Typical dimensions are less than 1 mm. Fuel capsules ia reactors could be larger (up to 1 cm) because of the iacreased driver energies available. 

Microcapsules can have a wide range of geometries and stmctures. Figure 1 illustrates three possible capsule stmctures. Parameters used to characteri2e microcapsules include particle size, size distribution, geometry, actives content, storage stabiHty, and core material release rate. 

Figure 4c also describes the spontaneous polymerisation ofpara- s.yX en.e diradicals on the surface of soHd particles dispersed in a gas phase that contains this reactive monomer (16) (see XylylenePOLYMERS). The poly -xylylene) polymer produced forms a continuous capsule sheU that is highly impermeable to transport of many penetrants including water. This is an expensive encapsulation process, but it has produced capsules with impressive barrier properties. This process is a Type B encapsulation process, but is included here for the sake of completeness. 

Pipelines to transport soHds are called freight pipelines, of which three different types exist pneumatic pipelines, the use of which is known as pneumotransport or pneumatic conveying slurry pipelines, which may also be called hydrotransport or hydrauHc conveying and capsule pipelines. When air or inert gas is used to move the soHds in the pipeline, the system is called a pneumatic pipeline and often involves a wheeled vehicle inside the pipeline, propelled by air moving through the pipe (25). Slurry pipelines involve the transport of soHd particles suspended in water or another inert Hquid. HydrauHc capsule pipelines transport soHd material within cylindrical containers, using water flow through the pipeline for propulsion. 

The protective nature of graphitic carbon against oxidation of core nanocrystals was demonstrated by an environmental test (80°C, 85% relative humidity, 7 days)[44]. Even after this test, XRD profiles revealed that the capsulated iron particles were not oxidized at... 

Engineering of Core-Shell Particles and Hollow Capsules... 

An important class of materials that originates from the precursor core-shell particles is hollow capsules. Hollow capsules (or shells ) can be routinely produced upon removal of the core material using chemical and physical methods. Much of the research conducted in the production of uniform-size hollow capsules arises from their scientific and technological interest. Hollow capsules are widely utilized for the encapsulation and controlled release of various substances (e.g., drugs, cosmetics, dyes, and inks), in catalysis and acoustic insulation, in the development of piezoelectric transducers and low-dielectric-constant materials, and for the manufacture of advanced materials [14],... 

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