Controlled cavities

Moroni L, Schotel R, Sohier J, De Wijn J R and Van Bhtterswijk C A (2006), Polymer hollow fiber three-dimensional matrices with controllable cavity and shell thickness . Biomaterials, 27(35), 5918-5926. DOI 10.1016/j. biomaterials.2006.08.015. 

Fig. 5.122. Three-mirror resonator for tunable cw OPO, resonant for pump and idler with polarization beam splitter and separately controlled cavity lengths Mi M2 and M3 M2 [5.3001...

In order to influence the distribution of products, we worked out how to control cavity sizes synthetically by intra- and extraann ar substituents X, Y (Fig. 5). 

The permeation rate is determined by the gravimetric method. The permeation device, after it has been assembled, is weighed and then placed in a temperature-controlled cavity with constant flow of nitrogen or clean air to sweep away the permeated chemical vapor. After a period of time, perhaps days, the tubing is weighed again and the permeation rate is determined by weight loss over elapsed time. Since... 

As was also discussed in this chapter, very significant progress has been made in the development of ferroelectrets. A large number of polymer electrets, including polyolefins (PP and PE), polyesters (PETP and PENP), COC, PC, and fiuoropolymers, were adopted to prepare ferroelectrets using a variety of techniques. By now, ferroelectrets with excellent electromechanical properties and with well-controlled cavity structures are becoming available. 

A new dimension to acid-base systems has been developed with the use of zeolites. As illustrated in Fig. XVIII-21, the alumino-silicate faujasite has an open structure of interconnected cavities. By exchanging for alkali metal (or NH4 and then driving off ammonia), acid zeolites can be obtained whose acidity is comparable to that of sulfuric acid and having excellent catalytic properties (see Section XVIII-9D). Using spectral shifts, zeolites can be put on a relative acidity scale [195]. An important added feature is that the size of the channels and cavities, which can be controlled, gives selectivity in that only... 

Injection Molding. Any standard design plunger or reciprocating screw injection machine can be used for PEA 340, although a reciprocating screw machine is preferred (32). Slow injection into mold cavities avoids surface or internal melt fracture, and control of ram speed is important at low... 

One successful total artificial heart is ABIOMED s electric TAH. This artificial heart consists of two seamless blood pumps which assume the roles of the natural heart s two ventricles (Fig. 7). The pumps and valves are fabricated from a polyurethane, Angioflex. Small enough to fit the majority of the adult population, the heart s principal components are implanted in the cavity left by the removal of the diseased natural heart. A modest sized battery pack carried by the patient suppHes power to the drive system. Miniaturized electronics control the artificial heart which mns as smoothly and quietly as the natural heart. Once implanted, the total artificial heart performs the critical function of pumping blood to the entire body (6). 

Metering Pumps. For small flow rates, such as dosing chemical additives where precise control is requited, progressive cavity self-contained pumping units are used. These can often handle shear-sensitive fluids or Hquids containing abrasive particles. These pumps are not as widely pubHci2ed or generally as well known in the Hterature as other pump types. 

In the Mooney shearing disk viscometer, a serrated disk is rotated ia a sample fixed ia a pressuri2ed cavity. The instmment was developed for mbber and other elastomeric materials and is a standard quaUty control iastmment ia the mbber iadustry (ASTM D1646). It is used to measure high viscosities givea ia arbitrary Mooaey units, but usually ca 7.5 x 10 mPa-s atlow(ca 1.5 ) shear rates. 

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