Industrial ecology: concepts and approaches.

Industrial ecology is a new approach to the industrial design of products and processes and the implementation of sustainable manufacturing strategies. It is a concept in which an industrial system is viewed not in isolation from its surrounding systems but in concert with them. Industrial ecology seeks to optimize the total materials cycle from virgin material to finished material, to component, to product, to waste product, and to ultimate disposal.

Perfection of quartz and its connection to crystal growth.

The perfection of cultured quartz and its connection to growth processes is reviewed. The principal macroscopic imperfection, ;creative flawing', is shown to be the hydrothermal crystal growth analog of dendritic growth and can be eliminated by the proper choice of growth direction and manipulation of conditions to minimize the effects of diffusion. Acoustic loss (1/Q) is proportional to the infrared absorption at the OH stretch frequency and is most likely due to a small (a few hundred molecules) number of aggregates of H(2)O, although lesser quantities of OH, which charge-compensate Al(+3) and Fe(+3) at Si(+4) sites, are also present.

Synthetic quartz with high ultraviolet transmission.

Quartz has been synthesized under hydrothermal conditions at rates of 1.78 mm/day in the presence of LiNO(2) in Ag lined and Ag plated systems, and it is shown that such quartz has optical transmission between 1500 A and 3 micro equal, and in some cases superior to, natural quartz. The uv cutoff at about 1500 A has been shown to be associated with Fe whose concentration may be reduced by procedures that reduce the concentration of charge compensating H+ in the lattice (growth in LiNO(2)) and by procedures which reduce the concentration of Fe in solutions (inert conditions).