Primary purpose

The primary purpose for expressing experimental data through model equations is to obtain a representation that can be used confidently for systematic interpolations and extrapolations, especially to multicomponent systems. The confidence placed in the calculations depends on the confidence placed in the data and in the model. Therefore, the method of parameter estimation should also provide measures of reliability for the calculated results. This reliability depends on the uncertainties in the parameters, which, with the statistical method of data reduction used here, are estimated from the parameter variance-covariance matrix. This matrix is obtained as a last step in the iterative calculation of the parameters. 

Large values of the uncertainty are assigned to the generated points, because the primary purpose of the generated points is not to have them fit accurately, but rather to maintain a reasonable slope of the function in the range outside the experimental points. 

Our primary purpose in this section is to point out some of the similarities and differences between step-growth and chain-growth polymerizations. In so doing we shall also have the opportunity to indicate some of the different types of chain-growth polymerization systems. 

Eigure 1 illustrates the Bayer process as it is practiced in the 1990s. The primary purpose of a Bayer plant is to process bauxite to provide pure alumina for the production of aluminum. World production of Al(OH)2 totaled ca 55 x 10 t in 1988. Practically all of the hydroxide was obtained by Bayer processing and 90% of it was calcined to metallurgical grade alumina (AI2O2). However, about 10% of the bauxite processed serves as feedstock to the growing aluminum chemicals industry. 

Selenium occurs in the slimes as intermetallic compounds such as copper silver selenide [12040-91 -4], CuAgSe disilver selenide [1302-09-6], Ag2Se and Cu2 Se [20405-64-5], where x < 1. The primary purpose of slimes treatment is the recovery of the precious metals gold, silver, platinum, palladium, and rhodium. The recovery of selenium is a secondary concern. Because of the complexity and variabiUty of slimes composition throughout the world, a number of processes have been developed to recover both the precious metals and selenium. More recently, the emphasis has switched to the development of processes which result in early recovery of the higher value precious metals. Selenium and tellurium are released in the later stages. Processes in use at the primary copper refineries are described in detail elsewhere (25—44). 

Other Constituents of Stream Water. The records reported ia Refs. 21 and 22 were obtaiaed for the primary purpose of evaluating the suitabihty of surface water resources of the United States for utilization by iadustry and for irrigation of agricultural lands ia the western part of the country. These stream waters also provide pubHc water suppHes for many municipahties. Evaluations of water quaUty for the latter purpose emphasize constituents that were not given detailed consideration ia Refs. 21 and 22 summaries, although there are references ia Ref. 21 to work done ia various state health laboratories and municipal treatment plants. 

Calcium carbonate is also used in industrial finishes and powder coatings. These paints typically include finer products the primary purpose is rheological and gloss control. Calcium carbonate is also used in paints to extend and enhance the use of titanium dioxide. This is accompHshed by using the finest of natural ground products or precipitated grades. 

The heart, a four-chambered muscular pump has as its primary purpose the propelling of blood throughout the cardiovascular system. The left ventricle is the principal pumping chamber and is therefore the largest of the four chambers in terms of muscle mass. The efficiency of the heart as a pump can be assessed by measuring cardiac output, left ventricular pressure, and the amount of work requHed to accomplish any requHed amount of pumping. 

Surfa.cta.nt, The primary purpose of a surfactant in toothpaste is to create a foam while the teeth are bmshed. This foam provides an enjoyable sensation. Secondarily, the surfactant helps remove material dislodged by the toothbmsh, and it may have minor effects on plaque accumulation (see Surfactants). 

Water-emulsifiable vehicles contain emulsifiers that may act as plasticizers after film formation, affecting the hardness. Water-soluble vehicles usually contain a neutralizing amine, the primary purpose of which is to solubihze the resin. These amines can influence the drying properties as they tend to complex the metal drier, thus affecting the catalytic activity. Acceptable results are usually obtained with trialkylamines such as dim ethyl eth a n o1 amine, trimethyl amine, and aminomethylpropan o1 (7). 

For some applications, either steam or electricity is simply not available and this makes the decision. It is rarely economic to install a steam boiler just for tracing. Steam tracing is generally considered only when a boiler already exists or is going to be installed for some other primary purpose. Additional electric capacity can be provided in most situations for reasonable costs. It is considerably more expensive to supply steam from a long distance than it is to provide electricity. Unless steam is available close to the pipes being traced, the automatic choice is usually electric tracing. 

Optimization The primary purpose of evaporator design is to enable production of the necessaiy amount of satisfactoiy product at the lowest total cost. This requires economic-balance calculations that may include a great number of variables. Among the possible variables are the following ... 

Continuous clarifiers generally are employed with dilute suspensions, principally industrial process streams and domestic municipal wastes, and their primary purpose is to produce a relatively clear overflow. They are basically identical to thickeners in design and layout except that they employ a mechanism of hghter construction and a drive head with a lower torque capability. These differences are permitted in clarification applications because the thickened pulp produced is smaller in volume and appreciably lower in suspended solids concentration, owing in part to the large percentage of relatively fine (smaller than 10 Im) solids. The installed cost of a clarifier, therefore, is approximately 5 to 10 percent less than that of a thickener of equal tank size, as given in Fig. 18-94. 

The CRZ/C s primary purpose is to keep the support zone free of eontaminants and hazards. The size and loeation of the CRZ/C should be based on the stability of site eonditions, the potential for dispersion of eontaminants and for unexpeeted events, and the proximity of unin-... 

It should be noted that the primary purpose of the ventilation systems described for abrasive blasting rooms and hospital isolation rooms is to prevent or minimize exposure to hazardous substances in those persons working outside the blasting or isolation room. The ventilation system may also reduce exposure for workers inside these rooms, but often the reduction is not sufficient to eliminate the need for respiratory protection. 

Data source Descriptive text in a given subject area whose primary purpose is to discuss a reliability or risk topic but which also contains some useful reliability data. 

Generally, the main pathways of exposure considered in tliis step are atmospheric surface and groundwater transport, ingestion of toxic materials that luu c passed tlu-ough the aquatic and tcncstrial food chain, and dermal absorption. Once an exposure assessment determines the quantity of a chemical with which human populations nniy come in contact, the information can be combined with toxicity data (from the hazard identification process) to estimate potential health risks." The primary purpose of an exposure assessment is to... 

Governments levy taxes to raise revenue and to discourage consumption of what is taxed. The primary purpose of United States federal and state gaso-... 

Lubrication. The primary purpose of chain lubrication is to maintain a Film of oil between the bearing surfaces in the joints, thus assuring maximum operating efficiency. This clean oil film must be maintained at all load-carrying points where relative motion occurs, that is, between the pin and bushing on the chain, and the chain and wheel sprocket teeth. Table 3-17 gives some recommended methods for various speeds. 

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