Crystalline, technology

Nylons prepared from aromatic diamines and diacids (aramids) can lead to very high-heat amorphous nylons such as Du Font s Nomex materials [poly(m-phenyleneisophthalamide)], or the highly oriented crystalline Kevlar fibers [poly(p-phenyleneterephthalamide)] derived from liquid-crystalline technology. Both of these aramids are sold as fibers. They have excellent inherent flame-retardant properties, and Kevlar exhibits a very high modulus. 

Figure 1.13 Photo of a test system consisting of 40 high-concentrating photovoltaic (PV) modules with 34% efficiency. This test system is a joint effort of Semprius (Durham, North Carolina, United States) and Siemens in coUahoration with the Spanish Institute of Concentration Photovoltaic Systems (ISFOC) and the University of Madrid. Leading modules manufacturers of conventional PV technologies achieved the maximum module efficiency of 20% with monocrystalline PV modules and 16% with poly crystalline technology.

A good compilation of the functions of fats in various food products is available (26). Some functions are quite subtle, eg, fats lend sheen, color, color development, and crystallinity. One of the principal roles is that of texture modification which includes viscosity, tenderness (shortening), control of ice crystals, elasticity, and flakiness, as in puff pastry. Fats also contribute to moisture retention, flavor in cultured dairy products, and heat transfer in deep fried foods. For the new technology of microwave cooking, fats assist in the distribution of the heating patterns of microwave cooking. 

There ate three basic technology options for making solar cells with do2ens of variations on each. These approaches ate conveniently grouped as follows thick (- 300 fiTo) crystalline materials, concentrator cells, and thin (- 1 fiva) semiconductor films. 

Crystalline silicon technology is the most mature and best understood of PV technologies. Researchers have identified the principal barriers that limit efficiency and, as a result, since the mid-1980s laboratory cells have climbed from 18 to - 23% and commercial production from 12 to - 15%. This is a particularly impressive achievement since crystalline silicon was regarded as mature in the early 1980s. 

It has been discovered that styrene forms a linear alternating copolymer with carbon monoxide using palladium II—phenanthroline complexes. The polymers are syndiotactic and have a crystalline melting point - 280° C (59). Shell Oil Company is commercializing carbon monoxide a-olefin plastics based on this technology (60). 

With the acquisition of the Thomson plant and technology, and the constmction of their own plant in Lafayette, Indiana, in the late 1980s, the A. E. Stanley Manufacturing Company dramatically increased crystalline fmctose production. On the strength of a growing appreciation for crystalline fmctose s unique physical and functional properties, its competitive pricing, and its successful penetration of specific mainstream food appHcations, worldwide crystalline fmctose production grew to more than 50,000 metric tons by 1992. In the same time period, crystalline fmctose prices feU dramatically to ca... 

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