Principal sources

The study of the operating experience available on similar installations is one of the principal sources of guidance criteria for the optimization of plants. 

During the design, operation and safety evaluation phases of every plant, data should be continuously collected to give information which can be recycled into future activities. The following question should be asked about the occurrence of an event at a plant Could it happen in the plant I am considering now If the answer is yes then appropriate measures of prevention/mitigation should be taken, within the minimum technical times but without unjustified haste. 

Various sets of design and safety criteria require that, during the important phases of a plant s life, the collection and recycling of experience are systematically performed within the responsible organization (see Appendix 3). 

The first source of data, because of its xmiversal nature, is the Incident Report System (IRS). This is jointly operated by the OECD and by the IAEA with information on events supplied by member countries. Often the contribution of the various countries is not in proportion with the respective number of operated plants due to local organization problems. Hopefully this situation will improve. 

The next source is the private service supplied by the World Association of Nuclear Operators (WANO) to its members. It represents a responsible and commendable response of the nuclear operators worldwide to the need to pool the available experience in order to attain ever safer plant operation. 

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The principal sources of utility waste are associated with hot utilities (including cogeneration) and cold utilities. Furnaces, steam boilers, gas turbines, and diesel engines all produce waste as gaseous c bustion products. These combustion products contain carbon... 

Silver occurs native and in ores such as argentite (Ag2S) and horn silver (AgCl) lead, lead-zinc, copper, gold, and copper-nickel ores are principal sources. Mexico, Canada, Peru, and the U.S. are the principal silver producers in the western hemisphere. 

Gr. neos, new, and didymos, twin) In 1841, Mosander, extracted from cerite a new rose-colored oxide, which he believed contained a new element. He named the element didymium, as it was an inseparable twin brother of lanthanum. In 1885 von Welsbach separated didymium into two new elemental components, neodymia and praseodymia, by repeated fractionation of ammonium didymium nitrate. While the free metal is in misch metal, long known and used as a pyrophoric alloy for light flints, the element was not isolated in relatively pure form until 1925. Neodymium is present in misch metal to the extent of about 18%. It is present in the minerals monazite and bastnasite, which are principal sources of rare-earth metals. 

D (+) Galactose is a constituent of numerous polysaccharides It is best obtained by acid hydrolysis of lactose (milk sugar) a disaccharide of d glucose and d galactose L (—) Galactose also occurs naturally and can be prepared by hydrolysis of flaxseed gum and agar The principal source of d (+) mannose is hydrolysis of the polysaccharide of the ivory nut a large nut like seed obtained from a South American palm... 

Although there are only three principal sources for the analytical signal—potential, current, and charge—a wide variety of experimental designs are possible too many, in fact, to cover adequately in an introductory textbook. The simplest division is between bulk methods, which measure properties of the whole solution, and interfacial methods, in which the signal is a function of phenomena occurring at the interface between an electrode and the solution in contact with the electrode. The measurement of a solution s conductivity, which is proportional to the total concentration of dissolved ions, is one example of a bulk electrochemical method. A determination of pH using a pH electrode is one example of an interfacial electrochemical method. Only interfacial electrochemical methods receive further consideration in this text. 

For both aqueous and nonaqueous liquids, MBSL is caused by chemical reactions of high energy species formed duriag cavitation by bubble coUapse, and its principal source is most probably not blackbody radiation or electrical discharge. MBSL is predominandy a form of chemiluminescence. 

Fatty acid CAS Registry Number Common name Designation Principal sources... 

On average, fluorine is about as abundant as chlorine in the accessible surface of the earth including oceans. The continental cmst averages about 650 ppm fluorine. Igneous, metamorphic, and sedimentary rocks all show abundances in the range of 200 to 1000 ppm. As of 1993, fluorspar was still the principal source of fluorine for industry. 

Economic Aspects. Pertinent statistics on the U.S. production and consumption of fluorspar are given in Table 4. For many years the United States has rehed on imports for more than 80% of fluorspar needs. The principal sources are Mexico, China, and the Repubflc of South Africa. Imports from Mexico have declined in part because Mexican export regulations favor domestic conversion of fluorspar to hydrogen fluoride for export to the United States. 

Fat Replacers. Eat has a ubiquitous presence in food and provides unique flavor, mouthfeel, and functional effects. At 9 kcal/g (38 kj/g), fat can be a principal source of dietary calories, and excessive consumption has been correlated with the incidence of chronic disease and morbidity. Health officials have strongly urged consumers to reduce fat intake to no more than 30% of daily calories. Therefore, a demand for low fat versions of high fat foods has developed. Eat replacers (qv) are the ingredients that make these foods possible. 

The eady juice industry was largely a salvage operation. The principal source of raw material was misshapen, poorly colored, or skin blemished fmit unsuitable for the fresh, canned, or frozen fmit market. In the 1990s, raw materials are selected for suitabiUty for juice production, except for apple juice production which still uses much cull fmit (4). 

Renewable carbon resources is a misnomer the earth s carbon is in a perpetual state of flux. Carbon is not consumed such that it is no longer available in any form. Reversible and irreversible chemical reactions occur in such a manner that the carbon cycle makes all forms of carbon, including fossil resources, renewable. It is simply a matter of time that makes one carbon from more renewable than another. If it is presumed that replacement does in fact occur, natural processes eventually will replenish depleted petroleum or natural gas deposits in several million years. Eixed carbon-containing materials that renew themselves often enough to make them continuously available in large quantities are needed to maintain and supplement energy suppHes biomass is a principal source of such carbon. 

Substitute or synthetic natural gas (SNG) has been known for several centuries. When SNG was first discovered, natural gas was largely unknown as a fuel and was more a religious phenomenon (see Gas, NATURAL) (1). Coal (qv) was the first significant source of substitute natural gas and in the early stages of SNG production the product was more commonly known under variations of the name coal gas (2,3). Whereas coal continues to be a principal source of substitute natural gas (4) a more recendy recognized source is petroleum (qv) (5). 

The principal source of helium is certain natural gas fields. The helium contents of more than 10,000 natural gases in various parts of the world have been measured (9). Helium concentrations of a few are Hsted in Table 2. In the United States, recovery of helium is economical only for helium-rich gases containing more than about 0.3 vol % belium. Most of the United States helium resources are located in the midcontinent and Rocky Mountain regions, and about 89% of the known United States supply is in the Hugoton field in Kansas, Oklahoma, and Texas the Keyes field in Oklahoma the Panhandle and Cliffside fields in Texas and the Riley Ridge area in Wyoming (11). 

Partial oxidation of heavy Hquid hydrocarbons requires somewhat simpler environmental controls. The principal source of particulates is carbon, or soot, formed by the high temperature of the oxidation step. The soot is scmbbed from the raw synthesis gas and either recycled back to the gasifier, or recovered as soHd peUetized fuel. Sulfur and condensate treatment is similar in principle to that required for coal gasification, although the amounts of potential poUutants generated are usually less. 

Other problems occur in the measurement of pH in unbuffered, low ionic strength media such as wet deposition (acid rain) and natural freshwaters (see Airpollution Groundwatermonitoring) (13). In these cases, studies have demonstrated that the principal sources of the measurement errors are associated with the performance of the reference electrode Hquid junction, changes in the sample pH during storage, and the nature of the standards used in caHbration. Considerable care must be exercised in all aspects of the measurement process to assure the quaHty of the pH values on these types of samples. 

Commercial mining of rare-earth reserves began ia the late 1800s. Mona2ite was the principal rare-earth source up until 1965. Thereafter bastnaesite production exceeded mona2ite production and as of 1992 bastnaesite, which is the world s principal source of rare earths, constituted 65% of world output of rare-earth minerals (see Table 5). In addition to the conventional ores, there are several other rare-earth resources having a low level of iadustrial production. 

Nutritional Value of Milk Products. Milk is considered one of the principal sources of nutrition for humans. Some people are intolerant to one or more components of milk so must avoid the product or consume a treated product. One example is intolerance to lactose in milk. Fluid milk is available in which the lactose has been treated to make it more digestible. The consumption of milk fat, either in fluid milk or in products derived from milk, has decreased markedly in the 1990s. Whole milk sales decreased 12% between 1985 and 1988, whereas the sales of low fat milk increased 165%, and skimmed milk sales increased 48% (35). Nutritionists have recommended that fat consumed provide no more than 30 calories, and that consumption of calories be reduced. Generally, a daily diet of 2000—3000 cal/d is needed depending on many variables, such as gender, type of work, age, body responses, exercise, etc. Further, there is concern about cholesterol [57-88-5] and density of fat consumed. Complete information on the nutritive value of milk and milk products is provided on product labels (36) (see also Table 4). 

The spectmm of oxo products ia Japan is far less diverse. Nearly 75% of Japan s total oxo capacity of 733,000 t is dedicated to the hydroformylation of propylene. 2-EH derived from -butyraldehyde is by far the dominant product. Other products iaclude linear alcohols and higher branched alcohols. Additionally, Japan is the world s principal source of branched heptyl alcohol. The three ptincipal Japanese oxo producers having slightly more than 70% of Japan s total oxo capacity are Mitsubishi Kasei, Kyowa Yuka, and Japan Oxocol. 

Shaped products used for adsorbent purposes are generally less sophisticated and therefore less expensive than catalytic products. In 1985, it was reported that 10,000 t/yr of activated alumina adsorbents were produced in the United States. North American producers of Bayer process-based activated aluminas include Alcoa, La Roche (formerly Kaiser Chemicals), Discovery, and Alcan. Gel-based activated aluminas are produced by La Roche, Vista, and several of the major catalyst manufacturers. In Europe, principal sources of supply are Rhc ne-Poulenc and Condea. 

Recovering ammonia as a by-product from other processes accounted for less than 1% of the total U.S. ammonia production in 1987. The principal source of by-product ammonia is from the coking of coal. In the coking operation, about 15—20% of the nitrogen present in the coal is Hberated as ammonia and is recovered from the coke oven gas as ammonium sulfate, ammonia Hquor, and ammonium phosphates. The recovery product depends on the scmbbing medium employed, sulfuric acid, milk of lime, and phosphoric acid, respectively. Ammonium sulfate recovery by the so-called semidirect process, is most widely employed. 

Either product can be favored over the other by proper selection of catalyst and reaction conditions. However, the principal source of DIPE is as a by-product from isopropyl alcohol production. Typically, excess DIPE is recycled over acidic catalysts ia the alcohol process where it is hydrated to isopropyl alcohol. DIPE is used to a minor extent ia iadustrial extraction and as a solvent. 

The R D function itself will be organized from company to company in very different ways. In some firms, the responsibiUty for innovation will be broadly shared and a distinct R D unit may cease to exist. In others, technical developments from an R D lab will be the principal source of innovation for the business. In still others, the primary task of the R D or technology group will be to obtain technology from outside the firm. Those involved in R D will need to make certain that their knowledge and talents impact the business irrespective of their precise function. The innovation process will become less linear (Fig. 8) as more feedback loops, technology transfer, and cooperative efforts are involved. 

Rubidium is found widely dispersed in potassium minerals and salt brines. LepidoHte [1317-64-2] a lithium mica having the composition KRbLi(0H,F)Al2Si20 Q, contains up to 3.5% Rb20 and is the principal source of the element. An ore that is basically poUucite [1308-53-8] ... 

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