Primary source

Once injection water treatment requirements have been established, process equipment must be sized to deal with the anticipated throughput. In a situation where water injection is the primary source of reservoir energy it is common to apply a voidage replacement policy, i.e. produced volumes are replaced by Injected volumes. An allowance above this capacity would be specified to cover equipment downtime. 

The primary source energy can be switched between 6, 9 and 11 MeV. So it is possible to penetrate and examine up to 0.6 m solid steel objects. In front of the accelerator a collimator... 

A number of structured databases have been developed to classify proteins according to the three-dimensional structures. Many of these are accessible via the World Wide Web, T1 protein databanlc (PDB [Bernstein d al. 1977]) is the primary source of data about the stru tures of biological macromolecules and contains a large number of structures, but many i these are of identical proteins (complexed with different ligands or determined at differet resolutions) or are of close homologues. 

Benzene was prepared from coal tar by August W von Hofmann m 1845 Coal tar remained the primary source for the industrial production of benzene for many years until petroleum based technologies became competitive about 1950 Current production IS about 6 million tons per year m the United States A substantial portion of this ben zene is converted to styrene for use m the preparation of polystyrene plastics and films... 

A breakdown of the mixed xylene supply sources in the United States is summarized in Table 1 (1). As shown in Table 1, the primary source of xylenes in the United States is catalytic reformate. In 1992, over 90% of the isolated xylenes in the United States were derived from this source. Approximately 9% of the recovered xylenes is produced via toluene disproportionation (TDP). In the United States, only negligible amounts of the xylenes are recovered from pyrolysis gasoline and coke oven light oil. In other parts of the world, pyrolysis gasoline is a more important source of xylenes. 

Residence times may vary slightly from those in Table 2 because of the differences in the primary source. Ref. 8... 

Percentage of meteorites seen to fall. Chondrites. Over 90% of meteorites that are observed to fall out of the sky are classified as chondrites, samples that are distinguished from terrestrial rocks in many ways (3). One of the most fundamental is age. Like most meteorites, chondrites have formation ages close to 4.55 Gyr. Elemental composition is also a property that distinguishes chondrites from all other terrestrial and extraterrestrial samples. Chondrites basically have undifferentiated elemental compositions for most nonvolatile elements and match solar abundances except for moderately volatile elements. The most compositionaHy primitive chondrites are members of the type 1 carbonaceous (Cl) class. The analyses of the small number of existing samples of this rare class most closely match estimates of solar compositions (5) and in fact are primary source solar or cosmic abundances data for the elements that cannot be accurately determined by analysis of lines in the solar spectmm (Table 2). Table 2. Solar System Abundances of the Elements ... 

In the United States, more than 16.3 x 10 kg of human-inedible raw materials are available each year, and the rendering industry is a valuable asset in diverting these into valuable ingredients for use primarily in animal foods (4). The three largest meat packers are responsible for nearly four-fifths of aU red meat production (5) and enormous amounts of rendered meat meal and animal fat. Three broiler producers account for about 40% of the total broiler production. American Proteins, Inc. (RosweU, Georgia), the world s largest processor of poultry by-products, produces more than 450,000 t of poultry meal, feather meal, and poultry fat each year. It also produces more than 100,000 t of fish meal, fish oil, and fish products each year. Pish meal production worldwide in 1986 was estimated at 6.23 x 10 t, which with the 125 x 10 t of meat and bone meal plus 6.67 x 10 t of feather meal and poultry by-product meal (6) is the primary source of animal proteins used by the pet food industry. 

Many valuable chemicals can be recovered from the volatile fractions produced in coke ovens. Eor many years coal tar was the primary source for chemicals such as naphthalene [91-20-3] anthracene [120-12-7] and other aromatic and heterocycHc hydrocarbons. The routes to production of important coal-tar derivatives are shown in Eigure 1. Much of the production of these chemicals, especially tar bases such as the pyridines and picolines, is based on synthesis from petroleum feedstocks. Nevertheless, a number of important materials continue to be derived from coal tar. 

Calcium. Calcium is the fifth most abundant element in the earth s cmst. There is no foreseeable lack of this resource as it is virtually unlimited. Primary sources of calcium are lime materials and gypsum, generally classified as soil amendments (see Calcium compounds). Among the more important calcium amendments are blast furnace slag, calcitic limestone, gypsum, hydrated lime, and precipitated lime. Fertilizers that carry calcium are calcium cyanamide, calcium nitrate, phosphate rock, and superphosphates. In addition, there are several organic carriers of calcium. Calcium is widely distributed in nature as calcium carbonate, chalk, marble, gypsum, fluorspar, phosphate rock, and other rocks and minerals. 

G. V. Samsonov and V. N. Bondarev, Germanides trans. A. Wald, Primary Sources, New York, 1970. 

Fuels ndEfficiency. Natural gas, oil, and electricity are the primary sources of energy propane is used as backup reserve in emergencies. Natural gas is the least expensive and most frequently used fuel, with heat content ranging from 34—45 MJ/nf (900—1200 Btu/ft ) for raw gas and approximately 3 MJ/m (80 Btu/fT) for air-gas mixtures. Fuel oil has heat content between 39—43 MJ/L (139,600—153,000 Btu/U.S. gal). Fuel oil is viscous at low temperature and must be heated before being fed to atomizing burners where it is mixed with air for combustion. 

Numeric. Researchers routinely use reported numeric measurements and data in thek work. Handbooks have been the primary source for locating this type of information, but numeric databases are now increasing in availabiUty. Advantages of searching numeric databases on-line include ease of use, dkect access to desked data, and abiUty to manipulate the information in the answer set. 

The primary sources of contamination in ion implantation come from metal atoms that may be etched off reactor fixtures, such as reactor wads, wafer holder, cHps, and so on. The pump oils used by the vacuum pumps may be a source of hydrocarbon contamination. The dopant sources themselves are not a significant source of contamination because unwanted ions are separated out from the beam during beam analysis. 

Secondary lead production made up over 70% of the lead produced in the United States in 1992 vs 54% in 1980. The amount of secondary lead produced was 698 X 10 t in 1988, 888 x 10 t in 1990, and 878 x 10 t in 1992. Of the 1.2 x 10 t of lead consumed in the United States in 1992, approximately 880,000 t were produced from the recycling of lead—acid batteries and 350,000 t from primary sources. A similar trend exists worldwide. In 1992, for the first time, slightly over half (51%) of the lead produced in the world came from secondary sources. 

Occurrence. Magnesium bromide [7789-48-2] MgBr2, is found in seawater, some mineral springs, natural brines, inland seas and lakes such as the Dead Sea and the Great Salt Lake, and salt deposits such as the Stassfurt deposits. In seawater, it is the primary source of bromine (qv). By the action of chlorine gas upon seawater or seawater bitterns, bromine is formed (see Chemicals frombrine). 

Batteries. Many batteries intended for household use contain mercury or mercury compounds. In the form of red mercuric oxide [21908-53-2] mercury is the cathode material in the mercury—cadmium, mercury—indium—bismuth, and mercury—zinc batteries. In all other mercury batteries, the mercury is amalgamated with the zinc [7440-66-6] anode to deter corrosion and inhibit hydrogen build-up that can cause cell mpture and fire. Discarded batteries represent a primary source of mercury for release into the environment. This industry has been under intense pressure to reduce the amounts of mercury in batteries. Although battery sales have increased greatly, the battery industry has aimounced that reduction in mercury content of batteries has been made and further reductions are expected (3). In fact, by 1992, the battery industry had lowered the mercury content of batteries to 0.025 wt % (3). Use of mercury in film pack batteries for instant cameras was reportedly discontinued in 1988 (3). 

Because the synthesis reactions are exothermic with a net decrease in molar volume, equiUbrium conversions of the carbon oxides to methanol by reactions 1 and 2 are favored by high pressure and low temperature, as shown for the indicated reformed natural gas composition in Figure 1. The mechanism of methanol synthesis on the copper—zinc—alumina catalyst was elucidated as recentiy as 1990 (7). For a pure H2—CO mixture, carbon monoxide is adsorbed on the copper surface where it is hydrogenated to methanol. When CO2 is added to the reacting mixture, the copper surface becomes partially covered by adsorbed oxygen by the reaction C02 CO + O (ads). This results in a change in mechanism where CO reacts with the adsorbed oxygen to form CO2, which becomes the primary source of carbon for methanol. 

Disposable polypropylene nonwoven fabrics are widely used as the coverstock for disposable baby diapers. The expansion of the disposable diaper market throughout the world has been the primary source of growth in the consumption of polypropylene in the fiber market. In addition, nonwoven polypropylene fabrics are used in a variety of other disposable sanitary products, such as baby wipes, adult incontinence, and feminine hygiene products. Use of polypropylene nonwovens in disposable medical apparel, such as surgical gowns, has increased as a means of reducing the spread of infection. 

There are two basic classes of potash-containing evaporites (2), those deposits that are rich ia magnesium sulfate, such as polyhaUte and kieserite, and those that are poor ia magnesium sulfate. The primary source of potash ia the magnesium-rich deposits is camakite, whereas both camakite and sylvite are found ia the magnesium-poor deposits. 

Capacity, Production, and Consumption. Ammonia production has worldwide significance about 85% of the ammonia produced is used for nitrogen fertilizers. As the primary source of fertilizer nitrogen, it is key to solving world food production requkements. The remaining 15% goes into various industrial products such as fibers, animal feeds, explosives, etc. 

A primary source of environmental pollution from printing ink comes from the metal-based pigments used, as well as various resins, waxes, and drying agents that are also part of the inks. These materials are added to inks regardless of the source of the oil. As a result, petroleum inks are just as suitable for landfill disposal under U.S. EPA regulations as are vegetable oil inks. 

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