Metric form

Color Difference Assessment. Color difference scales include those of Judd-Hunter, Macadam, Adams-Nickerson, ANLAB, and ANLAB40. AH of these have limitations in some way or another they are described in most texts (1 4). Each appHes only to the precise conditions used in thek determination and interconversion is not possible. Modifications of CIELAB in the metric form such as the CMC(1 c) system (14) promise improved performance for the future. 

Karrasik et al and has been modified to appear in metric form. The role used is often called the Scaling Laws,... 

The above development considers Ho to be an entity, and develops the nonsym-metric form of RSPT accordingly [18]. 

Some azomethines, eg HjGN.Q CHj have a tendency to polymerize to di- or tri-metric forms... 

Typical of a system in which many different phases occur (each with a small range of existence so that each may be encountered in non-stoichio-metric form) is the Cr-S system, where six phases occur in the composition range CrS0 95 to CrS15. 

In the previous section we discussed the notion of a discrete metric imposed upon the vertex set of a simple graph Because a set and its imposed metric form a metric space, any simpU graph is associated uniquely wiih a metric space (0) The vertex set of G is the basis of... 

More popular methods such as probe-beam deflection in its nonspectrophoto-metric form [177, 178] are now used to profile the diffusion layer, and in conjunction with electrochemical quartz crystal microbalance (EQCM) measurements, are used to monitor the diffusion layer ingress and egress of ions, particularly protons. Further details can be found in Chapter 2.7 in this volume. 

Chlorine cannot be stored economically or moved long distances. International movements of bulk chlorine are more or less limited to movements between Canada and the United States. In 1987, chlorine moved in the form of derivatives was 3.3 million metric tons or approximately 10% of total consumption (3). Exports of ethylene dichloride, vinyl chloride monomer, poly(vinyl chloride), propylene oxide, and chlorinated solvents comprise the majority of world chlorine movement. Countries or areas with a chlorine surplus exported in the form of derivatives include Western Europe, Bra2il, USA, Saudi Arabia, and Canada. Countries with a chlorine deficit are Taiwan, Korea, Indonesia, Vene2uela, South Africa, Thailand and Japan (3). 

The ores of most importance are fluorspar, CaF2 fluorapatite, Ca (P0 2Fj cryoHte [15096-52-3], Na AlF. Fluorspar is the primary commercial source of fluoiine. Twenty-six percent of the world s high quaHty deposits of fluorspar are ia North America. Most of that is ia Mexico. United States production ia 1987—1991 was 314,500 metric tons, most of which occurred ia the Illinois-Kentucky area. Imported fluorspar ia 1990—1991 represented about 82% of U.S. consumption 31% of U.S. fluorspar imports were from Mexico and 29% from China compared to 66% from Mexico ia the 1973—1978 period. The majority of the fluorine ia the earth s cmst is ia phosphate rock ia the form of fluorapatite which has an average fluorine concentration of 3.5%. Recovery of these fluorine values as by-product fluorosiHcic acid from phosphate production has grown steadily, partially because of environmental requirements (see Phosphoric acid and THE phosphates). 

Applications. The principal use for rigid polyurethane foams is for iasulation ia various forms utilized by a variety of iadustries. Lamiaates for resideatial sheatiag (1.2 to 2.5 cm thick with aluminum skins) and roofing board (2.5 to 10.0 cm thick with roofing paper skins) are the leading products with about 45 metric tons of Hquid spray systems also ia use. Metal doors iasulated by a pour-ia-place process coastitute another substantial use. 

Total hafnium available worldwide from nuclear zirconium production is estimated to be 130 metric tons annually. The annual usage, in all forms, is about 85 t. The balance is held in inventory in stable intermediate form such as oxide by the producers Teledyne Wah. Chang (Albany, Oregon) and Western Zirconium in the United States Ce2us in France Prinieprovsky Chemical Plant in Ukraine and Chepetsky Mechanical Plant in Russia (crystal bar). 

Metal Cleaning. About 204 thousand metric tons of HCl (100% basis) was consumed in 1993 for steel pickling, wherein the hydrochloric acid readily dissolves all of the various oxides present in the scale formed during the hot rolling process. Using suitable inhibitors such as alkyl pyridines, HCl reacts very slowly with the base metal rendering the surface so clean that it must be passivated with a mild alkaline rinse. 

Chlorine adds to ketene to form chloroacetyl chloride [79-04-9] (78). Chloroacetyl chloride (CAC) is used in large volume in the manufacture of the pre-emergence herbicides alachlor [15972-60-8] and butachlor [23184-66-9]. It is estimated that the CAC requirement for this appHcation was in excess of 45,000 metric tons in 1992. Significant volumes of CAC are also used in pharmaceutical manufacture, such as anesthetics of the Hdocaine type, and in the production of the tear gas chloroacetophenone [532-27-4]. Other commercial methods for the manufacture of CAC have been described (79). 

Uses. The sinter oxide form is used as charge nickel in the manufacture of alloy steels and stainless steels (see Steel). The oxide furnishes oxygen to the melt for decarburization and slagging. In 1993, >100, 000 metric tons of nickel contained in sinter oxide was shipped to the world s steel industry. Nickel oxide sinter is charged as a granular material to an electric furnace with steel scrap and ferrochrome the mixture is melted and blown with air to remove carbon as CO2. The melt is slagged, pouted into a ladle, the composition is adjusted, and the melt is cast into appropriate shapes. A modification of the use of sinter oxide is its injection directiy into the molten metal (33). 

Phthahc anhydride (1) is the commercial form of phthaUc acid (2). The worldwide production capacity for the anhydride was ca 3.5 x 10 metric tons ia 1993, and it was used ia the manufacture of plasticizers (qv), unsaturated polyesters, and alkyd resins (qv) (see Polyesters, unsaturated). Sales of terephthahc acid (3) and its dimethyl ester are by far the largest of any of the benzenepolycarboxyhc acids 14.3 x 10 t were produced in 1993. This is 80% of the total toimage of ah. commercial forms of the benzenepolycarboxyhc acids. Terephthahc acid is used almost exclusively for the manufacture of poly(ethylene terephthalate), which then is formed into textiles, films, containers, and molded articles. Isophthahc acid (4) and trimehitic anhydride (5) are commercial products, but their worldwide production capacities are an order of magnitude smaller than for terephthahc acid and its dimethyl ester. Isophthahc acid is used primarily in the production of unsaturated polyesters and as a comonomer in saturated polyesters. Trimehitic anhydride is used mainly to make esters for high performance poly(vinyl chloride) plasticizers. Trimesic acid (6), pyromehitic dianhydride (7), and hernimehitic acid (8) have specialized commercial apphcations. The rest of the benzenepolycarboxyhc acids are not available commercially. 

Many primary fatty amides which are available from various manufacturers are Hsted in Table 3. In 1986 approximately 55,000 metric tons of amides and bisamides were produced world wide (58), the majority of which are bisamides, followed in volume by primary amides. Most of these products are shipped in sohd form in bag or dmm quantities. Major producers of primary fatty amides are Akzo, Glyco, Humko, and Sherex. Bisamides are produced by Akzo, Milacron, and Syntex. There are over 100 producers of alkanolamides in the world, most of which are small specialized manufacturers to a specific industry. GAP, Henkel, Sherex, and Witco are among the principal producers. The most widely used alkanolamides are the Ai,Ai-bis(2-hydroxyethyl) fatty amides, mostly produced from middle-cut coco fatty acids (6% capryflc, 7% capric, 51% lauric, 19% myristic, 9% palmitic, and 2% stearic acids). An estimated 77,000 metric tons of alkanolamide was produced worldwide in 1986 (59). 

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