Other Constituents

The various classes of minor constituents can be divided into two groups. The first group consists of fatty acid derivatives such as mono- and diacylglycerols, phospholipids, waxes and esters of sterols. The second group includes classes of compounds not related chemically to fatty acids hydrocarbons, aliphatic alcohols, free sterols, tocopherols, chlorophylls, carotenoids and polar compounds such as tyrosol and hydroxytyrosol. 

Some minor constituents are present only in the crude oil. Refining removes phospholipids and phenols it also causes significant quantitative and qualitative changes in the other classes. 

Most of the minor constituents of olive oil are present in the 0.5-1.5% of unsaponihable matter. 

Tocopherols are important fat-soluble vitamins. They contribute to the stability of an oil and have an important role as quenchers of free radicals in vivo. Blekas and co-workers (1995) and Blekas and Boskou (1998) examined the role of a-tocopherol and its contribution to olive oil triacylglycerol stability. They found that a-tocopherol acts as an antioxidant at all levels but the antioxidant effect is greater at low (100 mg/kg) than at higher concentrations (500 and 1000 mg/kg). In the presence of more effective antioxidants such as o-diphenols, a-tocopherol did not show any significant antioxidant activity during the period of low peroxide accumulation but acted well when the primary oxidation products reached a critical level. 

The tocopherol content is highly variable. Concentrations may range from 5-300 mg/kg. Usual values for good quality oils lie between 100 and 300 mg/kg. Recent studies for the determination of tocopherols gave values ranging from 98-370 mg/kg in Greek oils (Psomiadou etal. 2000) and 36-314 mg/kg in Italian oils (Lo Curto et al. 2001). 

Several of the minor components of coal are of importance, because of the quantity present on occasion, but more so in some cases by virtue of the special properties they possess which are undesirable when the coal is used for certain purposes. For example, to arrive at a correct figure for the combustible carbon in coal, it is necessary to apply a correction for the quantity of carbonate associated with the sample. Combustion analyses determine only the total carbon. Again, coking coals should have low phosphorus content, and anthracites used for malting should contain only very small quantities of arsenic, so that the determination of these elements becomes necessary in certain cases. Since both are found normally in small amounts, they are not included in the general statement of the ultimate analysis but are reported separately. 

One particular test method (ASTM D-1756) covers the determination of carbon dioxide in coal in any form, such as mineral carbonate, from which carbon dioxide is released by action of mineral acids (e.g., hydrochloric acid). The method can be applied to high- and low-carbonate coals. The determination of carbon dioxide is made by decomposing with acid a weighed quantity of the sample in a closed system and absorbing the carbon dioxide in an absorbent (e.g., such as sodium 

This test method is intended for the use of industry to determine the performance of boiler furnaces and similar combustion reactors and aid in determining the quality of the solid residue from combustion. Any of several methods can be used to determine the total carbon content combined with any of several methods to determine carbonate carbon, and the calculation, by difference, of the combustible carbon remaining in the sample. Alternatively, this test method applies to the determination of total carbon remaining in a material after acidification with strong acid to evolve carbonate carbon. 

This protein binds firmly with riboflavin and 

The mineral content of egg white is 0.6%. Its Data on vitamins found in egg white are summa-composition is listed in Table 11.8. rized in Table 11.12. 

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Other constituents may be added to assist in the formation of uniform beads or to influence the use properties of the polymers through plasticization or cross-linking. These include lubricants, such as lauryl or cetyl alcohol and stearic acid, and cross-linking monomers such as di- or trivinylbenzene, diaHyl esters of dibasic acids, and glycol dimethacrylates. 

The separation of nitrogen from natural gas reHes on the differences between the boiling points of nitrogen (77.4 K) and methane (91.7 K) and involves the cryogenic distillation of a feed stream that has been preconditioned to very low levels of carbon dioxide, water vapor, and other constituents that would form soHds at the low processing temperatures. 

Alloys suitable for castings that ate to be bonded to porcelain must have expansion coefficients matching those of porcelain as well as soHdus temperatures above that at which the ceramic is fired. These ate composed of gold and palladium and small quantities of other constituents silver, calcium, iron, indium, tin, iridium, rhenium, and rhodium. The readily oxidi2able components increase the bond strength with the porcelain by chemical interaction of the oxidi2ed species with the oxide system of the enamel (see Dental materials). 

Milk consists of 85—89% water and 11—15% total soflds (Table 1) the latter comprises soflds-not-fat (SNF) and fat. Milk having a higher fat content also has higher SNF, with an increase of 0.4% SNF for each 1% fat increase. The principal components of SNF are protein, lactose, and minerals (ash). The fat content and other constituents of the milk vary with the animal species, and the composition of milk varies with feed, stage of lactation, health of the animal, location of withdrawal from the udder, and seasonal and environmental conditions. The nonfat soflds, fat soflds, and moisture relationships are well estabhshed and can be used as a basis for detecting adulteration with water (qv). Physical properties of milk are given in Table 2. 

Gas streams can be analy2ed for ammonia by bubbling a measured quantity of the gas through a boric acid solution to absorb the ammonia. The solution is then titrated against sulfuric acid. This analysis is applicable only if other constituents in the gas stream do not react with boric acid. 

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. 

The concentrations of the principal elements in marine and freshwaters are given in Figure 11. The concentrations of biologically regulated components, ie, C, N, P, and Si, vary with depth and are markedly influenced by the growth, distribution, and decay of phytoplankton and other organisms. The concentrations of other constituents, especially the salts, ie, Cl ,, and, are remarkably constant and are different from those in fresh... 

Precipitation softening processes are used to reduce raw water hardness, alkalinity, siHca, and other constituents. This helps prepare water for direct use as cooling tower makeup or as a first-stage treatment followed by ion exchange for boiler makeup or process use. The water is treated with lime or a combination of lime and soda ash (carbonate ion). These chemicals react with the hardness and natural alkalinity in the water to form insoluble compounds. The compounds precipitate and are removed from the water by sedimentation and, usually, filtration. Waters with moderate to high hardness and alkalinity concentrations (150—500 ppm as CaCO ) are often treated in this fashion. 

If a neutral chelate formed from a ligand such as acetylacetone is sufficiently soluble in water not to precipitate, it may stiH be extracted into an immiscible solvent and thus separated from the other constituents of the water phase. Metal recovery processes (see Mineral recovery and processing), such as from dilute leach dump Hquors, and analytical procedures are based on this phase-transfer process, as with precipitation. Solvent extraction theory and many separation systems have been reviewed (42). 

Clays composed of mixtures of clay minerals having from 20—50% of unsorted fine-grain nonclay materials are most satisfactory. Large amounts of iron, alkaHes, and alkaline earths, either in the clay minerals or as other constituents, cause too much shrinkage and greatiy reduce the vitrification range thus, a clay with a substantial amount of calcareous material is not desirable. Face bricks, which are of superior quaHty, are made from similar materials but it is even more desirable to avoid these detrimental components (see Building materials, survey). 

Local restrictions concerning the inclusion of preservatives and other constituents are dependent on the cosmetic product s method of use. 

Background Indirect coal liquefaction differs fundamentally from direct coal hquefaction in that the coal is first converted to a synthesis gas (a mixture of H9 and CO) which is then converted over a catalyst to the final product. Figure 27-9 presents a simplified process flow diagram for a typical indirect coal hquefaction process. The synthesis gas is produced in a gasifier (see a description of coal gasifiers earlier in this section), where the coal is partially combusted at high temperature and moderate pressure with a mixture of oxygen and steam. In addition to H9 and CO, the raw synthesis gas contains other constituents (such as CO9, H9S, NH3, N9, and CHJ, as well as particulates. 

Thus, it is uncertain to what extent the apparent protective effects of fruit and vegetable consumption on risk of stomach cancer can be attributable to their phytoestrogen content. This appears not to have been studied directly, and other constituents such as ascorbic acid (vitamin C), a-tocopherol (vitamin E) and /1-carotene may be potentially protective. 

Turboexpanders with Dry Gas Seals. As mentioned above, the application of dry gas seals in centrifugal compressors dates back to the early 1980s. They are useful in process compressors because seal gas leakage is considerably reduced. Also, the contact of process gas and other constituents that may dilute lubricating oil is minimized. 

The real atmosphere is more than a dry mixture of permanent gases. It has other constituents—vapor of both water and organic liquids, and particulate matter held in suspension. Above their temperature of condensation, vapor molecules act just like permanent gas molecules in the air. The predominant vapor in the air is water vapor. Below its condensation temperature, if the air is saturated, water changes from vapor to liquid. We are all familiar with this phenomenon because it appears as fog or mist in the air and as condensed liquid water on windows and other cold surfaces exposed to air. The quantity of water vapor in the air varies greatly from almost complete dryness to supersaturation, i.e., between 0% and 4% by weight. If Table 2-1 is compiled on a wet air basis at a time when the water vapor concentration is 31,200 parts by volume per million parts by volume of wet air (Table 2-2), the concentration of condensable organic vapors is seen to be so low compared to that of water vapor that for all practical purposes the difference between wet air and dry air is its water vapor content. 

Nitric oxide, NO, results from high-temperature combustion, both in stationary sources such as power plants or industrial plants in the production of process heat and in internal combustion engines in vehicles. The NO is oxidized in the atmosphere, usually rather slowly, or more rapidly if there is ozone present, to nitrogen dioxide, NO2. NO2 also reacts further with other constituents, forming nitrates, which is also in fine parhculate form. 

Fenner (11) has pointed out that short-lifetime constituents of the atmosphere such as nitrogen oxides, carbon monoxide, and nonmethane hydrocarbons may also play roles related to global warming because of their chemical relations to the longer-lived greenhouse gases. Also, SO, with a very short life interacts with ozone and other constituents to be converted to particulate sulfate, which has effects on cloud droplet formation. 

An understanding of the transformation of SO2 and NO. into other constituents no longer measurable as SOj and is needed to explain mass balance changes from one plume cross section to another. This loss of the primary pollutant SOj has been described as being exponential, and rates up to 1% per hour have been measured (30). The secondary pollutants generated by transformation are primarily sulfates and nitrates. 

The gaseous component typically contains hydrocarbons, hydrogen sulfide, ammonia, mercaptans, solvents, and other constituents, and is either discharged directly to the atmosphere or is combusted in a flare. The major air emissions from blowdown systems are hydrocarbons in the case of direct discharge to the atmosphere and sulfur oxides when flared. 

Engineering Considerations To effect the good engineering design of an activated carbon adsorption system, it is first necessary to obtain information on the following the actual cubic feet per minute (ACFM) of air to be processed by the adsorber, the temperature of gas stream, the material(s) to be absorbed, the concentration of the material to be adsorbed, and if the intended application is air pollution control such as odor control - then the odor threshold of the material to be adsorbed. In addition, data is needed on the presence of other constituents in the gas stream, and whether or not solvent recovery is economical. 

Use of Coagulants Coagulants may also react with other constituents of the wastewater, particularly anions such as phosphate and sulfate, forming hydrolysis products containing various mixtures of ions. The chemistry of the reactions is extremely complex and highly dependent on pH and alkalinity. The presence of... 

The gases also have other constituents mixed with them, typical ones being dusts, pollens, bacteria, viruses, mold spores, smoke particles, and the products of industrial activity such as SO2, H2, and S. Volcanic activity also adds various gases and dusts to the atmosphere. 

The term solubility thus denotes the extent to which different substances, in whatever state of aggregation, are miscible in each other. The constituent of the resulting solution present in large excess is known as the solvent, the other constituent being the solute. The power of a solvent is usually expressed as the mass of solute that can be dissolved in a given mass of pure solvent at one specified temperature. The solution s temperature coefficient of solubility is another important factor and determines the crystal yield if the coefficient is positive then an increase in temperature will increase solute solubility and so solution saturation. An ideal solution is one in which interactions between solute and solvent molecules are identical with that between the solute molecules and the solvent molecules themselves. A truly ideal solution, however, is unlikely to exist so the concept is only used as a reference condition. 

Details of the complex kinetic models and other constituent equations used in conjunction with the above equations can be found in Sheikh and Jones (1997). 

Aldehyde or Ketone may be separated from the other constituents by shaking the liquid, which should be free from water, with a saturated solution of sodium bisulphite, and decanting or filtering the liquid residue. If the liquid is soluble in water, like ethyl alcohol, it may piecipitate the bisulphite of sodium. This is prevented by adding a little ether befoie introducing the bisulphite into the liquid. 

With the exception of actinium, which is found naturally only in traces in uranium ores, these elements are by no means rare though they were once thought to be so Sc 25, Y 31, La 35 ppm of the earth s crustal rocks, (cf. Co 29ppm). This was, no doubt, at least partly because of the considerable difficulty experienced in separating them from other constituent rare earths. As might be expected for class-a metals, in most of their minerals they are associated with oxoanions such as phosphate, silicate and to a lesser extent carbonate. 

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