Proximate materials

The operations even of the esoteric alchemists were subject to wide variations but the central and crucial feature of the Great Work consisted in a prolonged and controlled heating of the proximate materials, under the right conditions, in the scaled vessel of Hermes. Thereafter it was often supposed that (he potency of the Stone could be greatly enhanced in the process called multiplication. Finally, the multiplied Stone was added to the fused base metal in the crowning operation of projection, thereby bringing about a rapid and spectacular transmutation. Finis coronal opus ... 

Influence of deposit environment (geomorphic unit) on difference in indoor and field test results. The loess of region for tests 5-9 has proximal materials, with loess mainly being composed of silty soil. But it is observed from Table 1 that test 6 is a special case and that the tests 5-9 are from west to east in geographic position in sequence from low to high. The corrected P ... 

See Rouelle [n.d.] p. 279f. As Venel made clear in a footnote, and as is also revealed in part by the names of the substances, extraction by solvents was not the only way of chemically separating the proximate materials of plants. The essential salts precipitated when the expressed juices of plants were evaporated, and the distilled waters and the essential oils were procured by wet distillation. The important point in all of these cases was that the temperature used in the separation of the materials was moderate, no higher than the boiling point of water. 

In reading Fourcroy s text it is important to interpret his term composes organiques in context. For example, in the introduction to his plant chemisto the heading des composes organiques v g taux refers to entire plants (Fourcroy [1801-1802] vol. Vll pp. 3-5). However in the context of his theory of composition and affinity this term refers to the proximate materials of plants (ibid. p. 54). 

In this section we consider electromagnetic dispersion forces between macroscopic objects. There are two approaches to this problem in the first, microscopic model, one assumes pairwise additivity of the dispersion attraction between molecules from Eq. VI-15. This is best for surfaces that are near one another. The macroscopic approach considers the objects as continuous media having a dielectric response to electromagnetic radiation that can be measured through spectroscopic evaluation of the material. In this analysis, the retardation of the electromagnetic response from surfaces that are not in close proximity can be addressed. A more detailed derivation of these expressions is given in references such as the treatise by Russel et al. [3] here we limit ourselves to a brief physical description of the phenomenon. 

Biodeterioration. For objects made out of organic materials, mold and insect attack are a principal cause of damage. Microbiological organisms can also be responsible for serious deterioration of outdoor stone. Museums, especially storage areas, are quite conducive to providing the conditions in which infestations can occur. Objects are stored in close proximity, and left untouched for prolonged periods, often with Htde if any ak movement. 

About 60% of the natural iron oxide pigments is used to color cement and other building materials (qv). About 30% is consumed in the production of paints. For coloring plastics and mbber, synthetic iron oxide pigments are preferred. The main advantage of the natural iron oxide pigments, as compared to the synthetic ones, is cost. However, the quaHty is inferior, and in most cases, they are consumed in close proximity to the mines. As colorants, the natural iron oxides are about 50% weaker than synthetically produced iron oxides. 

The primary siting factors which influence the selection of a plant location are as follows environmental considerations, labor avadabihty and productivity, raw material avadabihty, proximity to market, property cost, accessibdity to transportation, tax iacentives, electric power avadabdity and cost, and living conditions. 

Vitahium FHS ahoy is a cobalt—chromium—molybdenum ahoy having a high modulus of elasticity. This ahoy is also a preferred material. When combiaed with a properly designed stem, the properties of this ahoy provide protection for the cement mantle by decreasing proximal cement stress. This ahoy also exhibits high yields and tensile strength, is corrosion resistant, and biocompatible. Composites used ia orthopedics include carbon—carbon, carbon—epoxy, hydroxyapatite, ceramics, etc. 

The cost of transportation has an important effect on the marketabiUty of chemicals. For that reason, transportation, along with numerous other factors, is often a significant consideration in determining the location of chemical production faciUties. In addition, convenient and economical access to water and rail transportation and the interstate highway system, as well as proximity to raw materials and markets, may influence the choice of warehouse and terminal sites for storage and redistribution of chemical products (see Plant location). 

Isocyanates. Isocyanates in general are toxic chemicals and require great care in handling. Oral ingestion of substantial quantities of isocyanates can be tolerated by the human body, but acute symptoms may develop from the inhalation of much smaller amounts. The inhalation of isocyanates presents a ha2ard for the people who work with them as weU as the people who Hve in the proximity of an isocyanate plant. Adequate control of exposure is necessary to achieve a safe working environment. The suppHers Material Safety Data Sheets (MSDS) have to be consulted for the most current information on the safe handling of isocyanates. 

The fuel properties of wood can be summarized by ultimate and proximate analyses and deterrnination of heating value. The analytical procedures are the same as those for coal, but with some modifications. Analytical results generally vary about as much within a species as they do between species, except that softwood species generally have a higher carbon content and higher heating values than hardwood species because of the presence of more lignin and resinous materials in softwood species (see Fuels from waste). 

Table 6 shows the production of abrasive sihcon carbide in the United States and Canada (131). In 1988, four firms were producing cmde sihcon carbide under various trade names at six plants in the United States and Canada, The Exolon-ESK Co. General Abrasive/Dresser Co. Norton Co. and Superior Graphite Co. Most plants are located in areas where electrical power is, or at one time, was available at relatively low rates. Other considerations are availabihty of labor, reasonable air and water pollution standards, future expansion potential, and proximity of raw materials and markets. 

Graphite is frequently, although incorrectly, analyzed by the proximate method used for coal in which the volatile material is deterrnined by strongly beating the sample in a covered or luted cmcible. Some oxidation of the graphite always occurs so that the value obtained for volatile matter is high and thus the "fixed carbon" is too low. The method lacks both accuracy and precision. 

The behavior of colloidal suspensions is controlled by iaterparticle forces, the range of which rarely extends more than a particle diameter (see Colloids). Consequentiy suspensions tend to behave like viscous Hquids except at very high particle concentrations when the particles are forced iato close proximity. Because many coating solutions consist of complex mixtures of polymer and coUoidal material, a thorough characterization of the bulk rheology requires a number of different measurements. 

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