United States method

The United States methods of solvent recovery and drying of single-base propellants are described in detail in Ref 2, pp 26-32. These operations are conducted with proplnts in the shape of final grains. Prior to this, the colloided mass of proplnt is subjected, in sequence, to action of a preliminary blocking press, a macaroni press, final blocking press, graining and cutting opns (Ref 2, pp 23"25)... 

In the United States, methods for several pesticides at occupational levels in air are given in the National Institute for Occupational Safety and Health (NIOSH) Manual of Analytical Methods (Eller, 1994). The NIOSH methods for organochlo-rines and organophosphates utilize small traps with a particle filter backed up by two Amberlite XAD-2 resin beds. They are designed to be used with personal sampling pumps operating at flow rates of 0.2 to 1 L/min for maximum sample volumes of 60 to 240 L. Detection limits are in the 5 ng/m to 600 ng/m range. 

Much has been said concerning the differences between the British and United States methods of specifying explosives such as RD1333 lead azide, but little said about the similarities. The British military specification CS2637 contains a statement, "The composition RD1333 shall be manufactured by a process which will receive authoritative approval." The United States specification MIL L-46225C requires only that "a performance test detonator loaded with lead azide RD1333 shall form a hole in the lead disk 0.156 inch diameter." In essence the two specifications are the same. 

Nitration of phenoUulphonic acid m stationary reactors United States method... 

Measurement of octane numbers is carried out using a reference motor called CFR (Cooperative Fuel Research), referring to a series of studies conducted in 1928 in the United States in order to standardize the methods for characterizing motor fuels. 

The combination of sulfuric acid addition to propene followed by hydrolysis of the resulting isopropyl hydrogen sulfate is the major method by which over 10 lb of isopropyl alcohol is prepared each year m the United States... 

Over 10 ° lb of urea—most of it used as fertilizer—is produced annually m the United States by this method... 

From cumene Almost all the phenol produced in the United States is prepared by this method Oxi dation of cumene takes place at the benzylic posi tion to give a hydroperoxide On treatment with dilute sulfuric acid this hydroperoxide is converted to phenol and acetone... 

Trichloroacetic acid is manufactured in the United States by the exhaustive chlorination of acetic acid (38). The patent Hterature suggests two alternative methods of synthesis hydrogen peroxide oxidation of chloral (39) and hydrolytic oxidation of tetrachloroethene (40). 

Production of acetone by dehydrogenation of isopropyl alcohol began in the early 1920s and remained the dominant production method through the 1960s. In the mid-1960s virtually all United States acetone was produced from propylene. A process for direct oxidation of propylene to acetone was developed by Wacker Chemie (12), but is not beheved to have been used in the United States. However, by the mid-1970s 60% of United States acetone capacity was based on cumene hydroperoxide [80-15-9], which accounted for about 65% of the acetone produced. 

Selection of pollution control methods is generally based on the need to control ambient air quaUty in order to achieve compliance with standards for critetia pollutants, or, in the case of nonregulated contaminants, to protect human health and vegetation. There are three elements to a pollution problem a source, a receptor affected by the pollutants, and the transport of pollutants from source to receptor. Modification or elimination of any one of these elements can change the nature of a pollution problem. For instance, tall stacks which disperse effluent modify the transport of pollutants and can thus reduce nearby SO2 deposition from sulfur-containing fossil fuel combustion. Although better dispersion aloft can solve a local problem, if done from numerous sources it can unfortunately cause a regional one, such as the acid rain now evident in the northeastern United States and Canada (see Atmospheric models). References 3—15 discuss atmospheric dilution as a control measure. The better approach, however, is to control emissions at the source. 

The two procedures primarily used for continuous nitration are the semicontinuous method developed by Bofors-Nobel Chematur of Sweden and the continuous method of Hercules Powder Co. in the United States. The latter process, which uses a multiple cascade system for nitration and a continuous wringing operation, increases safety, reduces the personnel involved, provides a substantial reduction in pollutants, and increases the uniformity of the product. The cellulose is automatically and continuously fed into the first of a series of pots at a controlled rate. It falls into the slurry of acid and nitrocellulose and is submerged immediately by a turbine-type agitator. The acid is deflvered to the pots from tanks at a rate controlled by appropriate instmmentation based on the desired acid to cellulose ratio. The slurry flows successively by gravity from the first to the last of the nitration vessels through under- and overflow weirs to ensure adequate retention time during nitration. The overflow from the last pot is fully nitrated cellulose. 

In the United States the analytical methods approved by most states are ones developed under the auspices of the Association of Official Analytical Chemists (AOAC) (3). Penalties for analytical deviation from guaranteed analyses vary, even from state to state within the United States (4). The legally accepted analytical procedures, in general, detect the solubiUty of nitrogen and potassium in water and the solubiUty of phosphoms in a specified citrate solution. Some very slowly soluble nutrient sources, particularly of nitrogen, are included in some specialty fertilizers such as turf fertilizers. The slow solubihty extends the period of effectiveness and reduces leaching losses. In these cases, the proportion and nature of the specialty source must be detailed on the labeling. 

United States Pharmacopeia. Reference standards are requited in many USP and NF tests, and in a few FCC tests. The USPC distributes such standards domestically and has authorized international distribution by a number of organizations or companies. There are well over 1000 USP Reference Standards, including several for melting points, and also specimens of narcotics and other controlled substances. New standards are constantly under development as needed in various USP, NF, and FCC testing methods. 

The FDA has pubhshed methods for the deterrnination of residual solvents in spice extracts such as oleoresins and has limited the concentrations of those specific solvents that are permitted. Chlorinated hydrocarbons and benzene have been almost completely removed from use as extracting solvents in the United States their use continues overseas where toxicity regulations are less stringent. The presence of pesticides or herbicides in spices is rigidly controHed by the FDA. 

Several preparatory methods for the manufacture of Hg2p2 have been reported (5). Whereas no commercial appHcations for Hg2p2 have been reported, it is available from Advance Research Chemicals and Aldrich Chemicals in the United States. As of 1993, the U.S. market was a few kilograms per year at a price of 1500/kg. 

Several countries have developed their own standard test methods for cellular plastics, and the International Organization for Standards (ISO) Technical Committee on Plastics TC-61 has been developing international standards. Information concerning the test methods for any particular country or the ISO procedures can be obtained in the United States from the American National Standards Institute. The most complete set of test procedures for cellular plastics, and the most used of any in the world, is that developed by the ASTM these procedures are pubUshed in new editions each year (128). There have been several reviews of ASTM methods and others pertinent to cellular plastics (32,59,129—131). 

In 1993 there were over 100 organisations undertaking plasma fractionation woddwide, having plant capacities ranging from 4 to 1800 m /yr. Virtually all of these plants use methods based on those originally devised. Table 2 Hsts the six commercial manufacturers in the United States and the largest plasma fractionators woddwide. 

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