Large concentration

Because of the existence of numerous isomers, hydrocarbon mixtures having a large number of carbon atoms can not be easily analyzed in detail. It is common practice either to group the constituents around key components that have large concentrations and whose properties are representative, or to use the concept of petroleum fractions. It is obvious that the grouping around a component or in a fraction can only be done if their chemical natures are similar. It should be kept in mind that the accuracy will be diminished when estimating certain properties particularly sensitive to molecular structure such as octane number or crystallization point. 

Measured ernes range from large concentrations, such as approximately 0.6 M for sodium octanoate, to... 

AIO4 tetraliedra directly linked to an SiO. tetraliedron can be detennined from Si NMR since different chemical shifts are observed for tire corresponding Si nuclei. In tire absence of large concentrations of silanol defects, which... 

When large concentrations of water are added to the solutions, nitration according to a zeroth-order law is no longer observed. Under these circumstances, water competes successfully with the aromatic for the nitronium ions, and the necessary condition for zeroth-order reaction, namely that all the nitronium ions should react with the aromatic as quickly as they are formed, no longer holds. In these strongly aqueous solutions the rates depend on the concentrations and reactivities of the aromatic compound. This situation is reminiscent of nitration in aqueous nitric acid in which partial zeroth-order kinetics could be observed only in the reactions of some extremely reactive compounds, capable of being introduced into the solution in high concentrations ( 2.2.4). 

Ion-exchange columns can be substituted into the general HPLC instrument shown in Eigure 12.26. The most common detector measures the conductivity of the mobile phase as it elutes from the column. The high concentration of electrolyte in the mobile phase is a problem, however, because the mobile-phase ions dominate the conductivity, for example, if a dilute solution of HCl is used as the mobile phase, the presence of large concentrations of H3O+ and Ck produces a background conductivity that may prevent the detection of analytes eluting from the column. 

There are large concentrations of proven reserves ia specific areas of the globe such as the Middle East, North America, and the Confederation of Independent States. Thus the future of natural gas, worldwide, is dependent on the flow of natural gas across international boundaries on a long-term basis. This future is also dependent on the maintenance of an economic balance between the price of oil and the price of natural gas. 

The first factor to be considered when looking at the plasticization of a polymer is the need even though some polymers may be compatible with large concentrations of plasticizer, the resultant softening benefits maybe ofHtde use. Other factors are short- and long-term compatibiUty, ie, the abiUty of a polymer to accept and retain the plasticizer. 

Stabilization. A critical step in preparing sol—gel products and especially Type VI siHca optical components is stabilization of the porous stmcture as indicated in Figure 1. Both thermal and chemical stabilization is required in order for the material to be used in an ambient environment. The reason for the stabilization treatment is the large concentration of hydroxyls on the surface of the pores of these high (>400 /g) surface area materials. 

Sodium and Potassium. Sodium and potassium can be deterrnined by either atomic emission or absorption. Large concentrations of sodium can interfere with the potassium deterrnination in either of these methods. Excess sodium can be added to both the potassium standards and samples to minimize any variations in the samples. Proper positioning of the flame helps reduce sodium interference in atomic absorption. 

Calcium is a macronutrient essential for all organisms. Chlorine is a micronutrient essential for higher (ie, seed) plants but not considered essential for mammals. Above certain levels chloride is toxic to plants and animals, thus when considering calcium chloride, potentially large concentrations of calcium ion can be tolerated, but at these concentrations the chloride ion becomes toxic. 

A numerical solution of this equation for a constant surface concentration (infinite fluid volume) is given by Garg and Ruthven [Chem. Eng. ScL, 27, 417 (1972)]. The solution depends on the value of A. = n i — n )/ n — n ). Because of the effect of adsorbate concentration on the effective diffusivity, for large concentration steps adsorption is faster than desorption, while for small concentration steps, when D, can be taken to he essentially constant, adsorption and desorption curves are mirror images of each other as predicted by Eq. (16-96) see Ruthven, gen. refs., p. 175. 

A duplex heat exchanger tube containing a single small perforation was examined. Perforation occurred due to internal surface wastage beneath a deposit layer containing large concentrations of sulfur compounds (Fig. 4.28). 

Batch equipment located indoors. A release of flammable/toxic material tends to disperse slower than if the release is outdoors. May lead to large concentration buildup and result in operator exposure. Confined flammable releases are also more likely to result in explosion with larger overpressures. 

It is not necessary for a compound to depart from stoichiometry in order to contain point defects such as vacant sites on the cation sub-lattice. All compounds contain such iirndirsic defects even at the precisely stoichiometric ratio. The Schottky defects, in which an equal number of vacant sites are present on both cation and anion sub-lattices, may occur at a given tempe-ramre in such a large concentration drat die effects of small departures from stoichiometry are masked. Thus, in MnOi+ it is thought that the intrinsic concentration of defects (Mn + ions) is so large that when there are only small departures from stoichiometry, the additional concentration of Mn + ions which arises from these deparmres is negligibly small. The non-stoichiometry then varies as in this region. When the departure from non-stoichio-... 

When the liquid being pumped is known to have a large concentration of solids, the materials inside the pump should be changed to more... 

The outer balance gives the overall change between the outside boundaries of the RR system. The chemical change that occurred over the W kg catalyst is now expressed as the difference between the small flow times the large concentration change between in and out of the RR system. 

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