Various Constituents

Since the composition of the raw materials varies greatly, deviations from the standard can be recognized only by collective changes in the concentration of as many components as possible. 

For orange juice, Table 18.41 shows that when the guide values for certain components are exceeded or fallen short of, information is provided on the proportion of fruit, the use of expressed residues, acidification, sweetening, and microbiological spoilage. 

Quantity being measured/Component Mean Range of variation Guide value Indicator  

Quercetin-3-rutinoside Common, but not in strawberries Elderberry juice in strawberry juice 

Naringin or naringenin Grapefruits Grapefruit juice in orange juice 

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For homogeneous mixed samples it is relatively easy to detemiine the relative concentrations of the various constituents. For two elements one has approximately ... 

Plasma Collection. Human plasma is collected from donors either as a plasma donation, from which the red cells and other cellular components have been removed and returned to the donor by a process known as plasmapheresis, or in the form of a whole blood donation. These are referred to as source plasma and recovered plasma, respectively (Fig. 1). In both instances the donation is collected into a solution of anticoagulant (146) to prevent the donation from clotting and to maintain the stabiUty of the various constituents. Regulations in place to safeguard the donor specify both the frequency of donation and the volume that can be taken on each occasion (147). 

Adsorption systems employing molecular sieves are available for feed gases having low acid gas concentrations. Another option is based on the use of polymeric, semipermeable membranes which rely on the higher solubiHties and diffusion rates of carbon dioxide and hydrogen sulfide in the polymeric material relative to methane for membrane selectivity and separation of the various constituents. Membrane units have been designed that are effective at small and medium flow rates for the bulk removal of carbon dioxide. 

The long-term effects of CECs and HCECs leaking into the environment have been discussed. Combustion where aU ceUular plastics can evolve smoke containing carbon monoxide and in certain cases cyanide and other toxic gases from various constituents involved in thein manufacture is also a consideration. 

Metals less noble than copper, such as iron, nickel, and lead, dissolve from the anode. The lead precipitates as lead sulfate in the slimes. Other impurities such as arsenic, antimony, and bismuth remain partiy as insoluble compounds in the slimes and partiy as soluble complexes in the electrolyte. Precious metals, such as gold and silver, remain as metals in the anode slimes. The bulk of the slimes consist of particles of copper falling from the anode, and insoluble sulfides, selenides, or teUurides. These slimes are processed further for the recovery of the various constituents. Metals less noble than copper do not deposit but accumulate in solution. This requires periodic purification of the electrolyte to remove nickel sulfate, arsenic, and other impurities. 

The value of fractional distillation in the examination of essential oils cannot be overestimated. The various fractions may be examined and their specific gravities, optical rotations, and refractive indices determined. The combination of these figures will often give the experienced analyst the most useful information and save him many hours needless work. Experience alone, however, will teach the chemist to make the fullest use of the results so obtained. In most cases distillation under reduced pressure is necessary on account of the risk of decomposing the various constituents of the oil. The use of a Briihl receiver (or any similar contrivance), which is easily obtained from any apparatus maker. 

The solid fuel composition is, therefore, concerned with the pursuit of higher I p involving both flame temperature elevation and molecular weight reduction. Concomitantly, it is desirable to have high heat of combustion, which also dictates the combustion chamber temperature. The actual composition is, therefore, set on the basis of the energy quantum inherent in the various constituents. 

The effectiveness of incineration has most commonly been estimated from the heating value of the fuel, a parameter that has little to do with the rate or mechanism of destraction. Alternative ways to assess the effectiveness of incineration destraction of various constituents of a hazardous waste stream have been proposed, such as assessment methods based on the kinetics of thermal decomposition of the constituents or on the susceptibility of individual constituents to free-radical attack. Laboratory studies of waste incineration have demonstrated that no single ranking procedure is appropriate for all incinerator conditions. For example, acceptably low levels of some test compounds, such as methylene chloride, have proved difficult to achieve because these compounds are formed in the flame from other chemical species. 

Fluoride glasses are difficult to classify because the various constituents can be added to the fusion mixture in several ways. However, glasses of the Laboratory of the Government Chemist (Wilson Kent, 1973 Kent, Lewis Wilson, 1979 Wilson et al., 1980 Hill Wilson, 1988a), which form the basis of many commercial cements, can be represented as... 

Solvent polymeric membranes, conventionally prepared from a polymer that is highly plasticized with lipophilic organic esters or ethers, are the scope of the present chapter. Such membranes commonly contain various constituents such as an ionophore (or ion carrier), a highly selective complexing agent, and ionic additives (ion exchangers and lipophilic salts). The variety and chemical versatility of the available membrane components allow one to tune the membrane properties, ensuring the desired analytical characteristics. 

The determination of the amounts in which the various constituents of a material are present. 

Because soil contains pores that tightly hold water, it is not sufficient to simply dry soil at 100°C. On the other hand, heating too much above 100°C will cause changes in soil mass due to loss of various constituents other than water. The compromise is to heat the soil slightly above 100-105°C for 24... 

Titration is a general word used in many different disciplines. Any time a solution of known concentration is used to find the amount of an unknown component in another solution, it can be called a titration. Although this type of analysis is very old, it still finds widespread used in chemical analysis. Titrations are used in soil analysis to measure soil acidity, soil organic matter content, and various constituents isolated from soil, particularly ammonia. 

Concerns have been focused on the various constituents present in plant protein sources or products which may have, for the most part, deleterious effects numerous recent reviews detailing various aspects have been published (e.g.,. In the... 

Fractional Distillation.—-When several volatile reaction products are to be separated from one another the procedure is not so simple as described above. In proportion as the boiling points of the various constituents approach each other the separation becomes more difficult, and it is not easy with the help of the usual laboratory apparatus to separate with any degree of precision substances which differ in boiling point by 10°. 

The outlet from the column is connected to a detector usually fitted with an automatic recorder that permits exclusively the monitoring of the relative concentrations of the various constituents present in the sample. However, one may also make use of an automatic fraction collector duly attached to the outlet from the column, if required. The various experimental parameters stated below are normally given in the official monograph, namely ... 

Second-order and third-order results often bracket the true correction to pF - Three schemes that scale the third-order terms in various ways are known as the Outer Valence Green s Function (OVGF) [8], In OVGF calculations, one of these three recipes is chosen as the recommended one according to rules based on numerical criteria. These criteria involve quantities that are derived from ratios of various constituent terms of the self-energy matrix elements. Average absolute errors for closed-shell molecules are somewhat larger than for P3 [31]. 

Several hundred individual hydrocarbon chemicals defined as petroleum-based have been identified. Furthermore, each individual crude oil and each individual petroleum product has a specific mixture of the various constituents because of the variation in petroleum composition (Chapter 2), and this variation is reflected in the composition of the finished petroleum product. At this point it is worthy of note that the term petroleum hydrocarbons (PHC) is widely used to refer to the hydrogen- and carbon-containing compounds originating from crude oil, but petroleum hydrocarbons should be distinguished from total petroleum hydrocarbons because the term total petroleum hydrocarbons is specifically associated with environmental sampling and analytical results (Weisman, 1998 CFR, 2004). 

Also known as specific susceptibility. mas sa.sep-ta bil-ad-e mass-to-charge ratio analychem In analysis by mass spectroscopy, the measurement of the sample mass as a ratio to its ionic charge. mas to charj. ra sho ) matrix analy chem The analyte as considered in terms of its being an assemblage of constituents, each with its own properties. ma-triks matrix effects analy chem 1. The enhancement or suppression of minor element spectral lines from metallic oxides during emission spectroscopy by the matrix element (such as graphite) used to hold the sample. 2. The combined effect exerted by the various constituents of the matrix on the measurements of the analysis. ma triks i.feks )... 

Various constituents in plant foods can impede Ca absorption. Plant-based diets can be high in oxalate and phytate, which are recognized as inhibitors of Ca absorption. In fact, Ca absorption is considered to be inversely proportional to oxalic acid content of the food (Weaver et al, 1999). Phytic acid poses Ca absorption problems for those species imable to endogenously synthesize phytase (e.g., humans, birds, and pigs). The Ca in CCM is chelated with the citrate and malate anions, which may make CCM less reactive than other sources of Ca toward food components known to interact with Ca " cations. For example, Lihono et al (1997a) reported data suggesting that the Ca in CCM may be less likely to complex with phytates than other Ca salts. Qn this basis, CCM may be more appropriate for the fortification of soy or other phytic acid-containing products. 

Thus glass which adsorbs the various constituents of the air more readily than it adsorbs mercury is not wetted by the metal, but if the adsorbed gas be removed from the surface, e.g. with the aid of a high vacuum such as obtains in a MacLeod gauge, the mercury may be caused to adhere to the glass. 

Latex materials are classified into three types according to the type of surfactant used in the production of the latexes cationic (positively charged), anionic (negatively charged) and nonionic (uncharged). The action of the emulsifier (surfactant) is due to its molecules having both hydrophilic and hydrophobic parts and the properties of the latex formed are very dependent on how the various constituents are put together. 

The effectiveness of each admixture may vary, depending on its concentration in the concrete, the time of addition in the mixing cycle and various constituents of the concrete. Although each class of admixture is defined by its main effect (i.e. water reduction, set acceleration), it may have one or more secondary effects (retardation of set, increased bleeding, air entrainment) and its use may result in side effects. Side effects are those modifications of properties produced in the concrete that, even though unsought, are both inevitable and independent of an admixture s main function. Prior to selecting an admixture for an intended application, these... 

Modem concretes often incorporate a mixture of chemical and mineral admixtures, each of which may interact with the various constituents of cements and influence cement hydration reactions. The admixture-cement interactions may in fact be viewed as the reaction between two complex chemical systems - the multicomponent, multiphasic inorganic materials in the cement and the organic compounds of multicomponent admixture systems. For example, lignosulfonate water-reducers are intrinsically complex mixtures of chemical compounds derived from the chemical degradation of lignin, while synthetic admixtures such as superplasticizers contain species with a broad distribution of molecular weights, reaction products, or other chemicals added for a specific purpose [125]. The performance of an admixture in concrete is highly dependent on many... 

Under steady state conditions, the relative removal rates of material from the surface must reflect the bulk concentration. This criteria is the driving force which determines the concentrations of the various constituents at the surface. For a two component system, this implies that CJC2 = r,0,/T202 where C, and are concentrations of the two constituents in the bulk material. Therefore,... 

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