Commercially feasible

Rhodium occurs native with other platinum metals in river sands of the Urals and in North and South America. It is also found with other platinum metals in the copper-nickel sulfide area of the Sudbury, Ontario region. Although the quantity occurring here is very small, the large tonnages of nickel processed make the recovery commercially feasible. The annual world production of rhodium is only 7 or 8 tons. 

Carbon and Graphite Fibers. Carbon and graphite fibers (qv) are valued for their unique combination of extremely high modulus and very low specific gravity. Acrylic precursors are made by standard spinning conditions, except that increased stretch orientation is required to produce precursors with higher tenacity and modulus. The first commercially feasible process was developed at the Royal Aircraft Fstablishment (RAF) in collaboration with the acrylic fiber producer, Courtaulds (88). In the RAF process the acrylic precursor is converted to carbon fiber in a two-step process. The use of PAN as a carbon fiber precursor has been reviewed (89,90). 

Copolymerization is effected by suspension or emulsion techniques under such conditions that tetrafluoroethylene, but not ethylene, may homopolymerize. Bulk polymerization is not commercially feasible, because of heat-transfer limitations and explosion hazard of the comonomer mixture. Polymerizations typically take place below 100°C and 5 MPa (50 atm). Initiators include peroxides, redox systems (10), free-radical sources (11), and ionizing radiation (12). 

Polymerization. The first successful polymerizations of VDE in aqueous medium using peroxide initiators at 20—150°C and pressures above 30 MPa were described in a patent issued in 1948 (73). About a year later, the first copolymerizations of VDE with ethylene and halogenated ethylenes were also patented (74). After a hiatus of over 12 years a commercially feasible process was developed and PVDE was ready for market introduction (2). 

Oil Fields. Oil field waters in the United States containing lithium have been identified in 10 states. The greatest concentrations are in waters from the Smackover formation of southern Arkansas and eastern Texas. Concentrations from this formation have been measured from 300—600 ppm in waters originating at a 2500—3300 m depth. Recovery of lithium from this resource would only be commercially feasible if a selective extraction technique could be developed. Lithium as a by-product of the recovery of petroleum (qv), bromine (qv), or other chemicals remains to be exploited (12). 

Nylon-6 [25038-54-4] was first made in 1899 by heating 6-aminohexanoic acid (143), but its commercially feasible synthesis from caprolactam was discovered by Paul Schlack at 1. G. Farbenindustrie in 1938. Like nylon-6,6, it is a tough, white translucent, semicrystalline sofld, but melts at a lower temperature (T = 230° C. The physical properties and primary producers of nylon-6 are Hsted in Tables 9 and 10, respectively. 

The use of alternative fibers depends on the abdity of the fibers to bond to one another with sufficient strength to form a cohesive sheet. However, practical considerations determine whether pulp from a particular plant source is commercially feasible. These include the characteristics of the fiber, such as strength and optical properties, supply, yield of desirable fibers, waste generated, and the abdity to store the fibers without degeneration. 

The electro deposition of tungsten aUoys of iron, nickel, and cobalt is commercially feasible but has remained largely experimental. The properties of these aUoys should, however, be of sufficient interest for engineering appHcations. 

CP esters are generally prepared as the ammonium salt [9038-38-4] by the reaction of cellulose with phosphoric acid and urea at elevated temperatures (130—150°C). The effects of temperature and urea/H PO /cellulose composition on product analysis have been investigated (33). One of the first commercially feasible dameproofing procedures for cotton fabric, the Ban-Flame process (34,35), was based on this chemistry. It consists of mixing cellulose with a mixture of 50% urea, 18% H PO, and 32% water. It is then pressed to remove excess solution, heated to 150—175°C for 5—30 minutes, and thoroughly washed (36). 

Chemical Synthesis. The chemical synthesis of citric acid was reported in 1880 (27). Since then, many different synthetic routes have been investigated, reported, and patented (28—36). However, none of these have proven to be commercially feasible. 

Vapor-phase oxidation of cyclohexane is commercially feasible, but the preferred route is Hquid-phase cyclohexane oxidation (2). In the latter... 

During this period, the ICI laboratories were also making their other great contribution to the range of plastics materials—the product which they marketed as Perspex, poly(methyl methacrylate). As a result of work by two of their chemists, R. Hill and J. W. C. Crawford, it was found that a rigid transparent thermoplastics material could be produced at a commercially feasible cost. The material became invaluable during World War II for aircraft glazing and to a lesser extent in the manufacture of dentures. Today poly(methyl methacrylate) is... 

The process engineer also develops tests and interprets data and information from the research pilot plant. He aids in scaling-up the research qpe flow cycle to one of commercial feasibility. 

T.T.S curves as those in Fig. 3.21 can be developed for material cooled very rapidly following solution treatment but the C curve range is a OO-550°C and the nose is at very short times. Freedom from sensitisation in welding can be obtained by ensuring extremely low carbon (and nitrogen) but such levels are not commercially feasible. Stabilisation by niobium and titarium is feasible, but higher ratios are needed than with austenitic steels. With most of the super ferritic group a combination of a practical low carbon level and titanium addition is used. 

Of the chemical EOR technologies, surfactant flooding is the most complex, the farthest from commercial feasibility, and the most challenging in terms of research needs, yet it has the greatest ultimate potential. It involves injecting surfactants. 

For environmental reasons, other attempts have been made to reduce the amount of conventional electrolyte added. Lowering the liquor ratio will in itself reduce the amount of electrolyte required. In one commercially feasible system [72], a range of direct dyes was successfully screened to select members that could be applied efficiently to give 95-100% exhaustion using significantly less electrolyte than usual. Thus at applied depths up to 2-3%, only 2-5 g/1 salt is required navy and black dyeings can be produced with only 7.5-10 g/1 salt compared with the conventional 25 g/1 addition. 

Besides their essential roles in nature, isoprenoids are of commercial importance in industry. Some isoprenoids have been used as flavors, fragrances, spices, and food additives, while many are used as pharmaceuticals to treat an array of human diseases, such as cancer (Taxol), malaria (artemisinin), and HIV (coumarins). In contrast to the huge market demand, isoprenoids are present only in low abundance in their host organisms. Thus, isolation of the required isoprenoids consumes a large quantity of natural resources. Furthermore, owing to their structural complexity, total chemical synthesis is often not commercially feasible. For these reasons, metabolic engineering may provide an alternative to produce these valuable isoprenoids [88,89]. 

The use of AAAs as feed supplements appears an attractive approach either in itself or in combination with pro-, pre- and synbiotics, but the lack of animal feeding studies in which the efficacy of this approach could be determined makes it difficult to assess to what extent a two-barrier (targeting control at both the stomach and intestinal level) approach is commercially feasible. Also, since the viability of probiotics may also be affected by the use of AAA to increase the disinfection activity of the stomach, probiotics may need to be formulated in a way that protects them during stomach transfer. However, its potential should be determined in future research. 

For illustration, we consider a simplified treatment of methane oxidative coupling in which ethane (desired product) and CO, (undesired) are produced (Mims et al., 1995). This is an example of the effort (so far not commercially feasible) to convert CH, to products for use in chemical syntheses (so-called Q chemistry ). In this illustration, both C Hg and CO, are stable primary products (Section 5.6.2). Both arise from a common intermediate, CH, which is produced from CH4 by reaction with an oxidative agent, MO. Here, MO is treated as another gas-phase molecule, although in practice it is a solid. The reaction may be represented by parallel steps as in Figure 7.1(a), but a mechanism for it is better represented as in Figure 7.1(b). 

Despite the wealth of information available on the biochemistry, genetics, and nutritional values of plant proteins, people eat foods that look, smell, and taste good not because of nutritional importance. Thus, new blended plant foods or protein-supplemented snacks or food products will have to look and taste like the traditional items if they are to gain sufficient acceptance to become commercially feasible. Absolute food... 

Mark returned to research after the modernization program was organized and operating smoothly. Limited to cellulose chemistry by the necessity of commercial feasibility, he studied cellulose acetate and the effect of the degree of acetylation on product solubility. At the same time he worked closely on the development of suitable analytical methods to measure molecular weight distribution and the degree of functionality. 

The large variety of composite membranes reported In the literature are not necessarily represented by the structure shown In Figure 18. Nevertheless, the membranes which have materialized as commercially feasible, operating reverse osmosis units (e.g.,... 

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