Optimum composition

A high-nickel alloy is used for increased strength at elevated temperature, and a chromium content in excess of 20% is desired for corrosion resistance. An optimum composition to satisfy the interaction of stress, temperature, and corrosion has not been developed. The rate of corrosion is directly related to alloy composition, stress level, and environment. The corrosive atmosphere contains chloride salts, vanadium, sulfides, and particulate matter. Other combustion products, such as NO, CO, CO2, also contribute to the corrosion mechanism. The atmosphere changes with the type of fuel used. Fuels, such as natural gas, diesel 2, naphtha, butane, propane, methane, and fossil fuels, will produce different combustion products that affect the corrosion mechanism in different ways. 

Poly(acrylamide-diallylethylamine-HCl) (cationic polyacrylamide pAM-HCl) was prepared by gamma radiation-initiated copolymerization of acrylamide with di-allylethylamine-HCI in aqueous solution at the optimum composition for copolymerization of acrylamide with diallylamine derivatives [61]. 

Optimum compositions may be planned with the help of plots of /rmax versus solvent composition, where /cmax increases with increasing amounts of the low-viscosity component, reaching its maximum at /fmax, and then decreases again in accordance with increasing association of the electrolyte [221], For this approach, many examples exist[15]. 

These conclusions from the infrared reflectance spectra recorded with Pt and Pt-Ru bulk alloys were confirmed in electrocatalysis studies on small bimetallic particles dispersed on high surface area carbon powders.Concerning the structure of bimetallic Pt-Ru particles, in situ Extended X-Ray Absorption Fine Structure (EXAFS>XANES experiments showed that the particle is a true alloy. For practical application, it is very important to determine the optimum composition of the R-Ru alloys. Even if there are still some discrepancies, several recent studies have concluded that an optimum composition about 15 to 20 at.% in ruthenium gives the best results for the oxidation of methanol. This composition is different from that for the oxidation of dissolved CO (about 50 at.% Ru), confirming a different spatial distribution of the adsorbed species. 

Determination of the optimum composition of the mobile phase using the PRISMA model... 

Coman et al. [82] used a new modeling of the chromatographic separation process of some polar (hydroxy benzo[a]pyrene derivatives) and nonpolar (benzo[a]pyrene, dibenz[a,/ ]anthracene, and chrysene) polycyclic aromatic compounds in the form of third-degree functions. For the selection of the optimum composition of the benzene-acetone-water mobile phase used in the separation of eight polycyclic aromatic compounds on RP-TLC layers, some computer programs in the GW-BASIC language were written. 

Other established techniques to aid in the analysis of mixture models include the use of gradients to measure the rate of response change (10), graphical analysis of the response change versus individual component changes (11), and the determination of component effects within constrained regions (6). Each of these techniques, while very useful in the interpretation of component effects do not lend themselves to the determination of the optimum composition, the most important point in the formulation space. 

P.C. Meier, W.E. Morf, M. Laubli, and W. Simon, Evaluation of the optimum composition of neutral-carrier membrane electrodes with incorporated cation-exchanger sites. Anal. Chim. Acta 156,1—8 (1984). 

As anodes age their performance gradually deteriorates, and thus small changes in electrolyte composition must be made to maintain current efficiency and energy consumption. The EMOS system has been used by some operators to determine the optimum composition of the electrolyte in these circumstances and in some cases to control the composition selectively for each cell line. 

The structure of these macroassemblies of nano building blocks also raises interesting questions about optimum composite design. The fact that the porosity of these... 

The optimum composition is still to be determined for energy storage, power capability, lifetime, and cost considerations. 

Chromatography.—A computer programme has been developed for prediction of the optimum compositions of binary stationary phases for the g.l.c. separation of mixtures of steroids. Problems in the gas chromatography of H- and C-labelled... 

Creation of an optimum composition of modifiers (promoters, inhibitors, selective poisons, etc.) ... 

In 1988, Cava and co-workers also prepared (88a) a quaternary oxide, Ba/K/Bi/O, and observed superconductivity at -28 K. This compound was the first "non-transition metal" oxide with a Tc above the legendary "alloy record" of 23 K. Further studies indicated (88a) that the optimum composition for "high temperature" superconductivity in this system was Ba0 6K0 4BiO3 x, having a Tc of 30.5 K (Figure 17). The samples were multiphase, and the superconducting fraction varied from 3 to 25%. Superconductivity for the rubidium-substituted compound was observed at -28.6 K. 

Situations can be imagined, in which more than one solute has to be extracted from a sample. Such situations are, for instance, the extraction of an analyte simultaneously with an internal standard or a drug simultaneously with one or more major metabolites or co-drugs. Under these conditions, the aim of an extraction procedure is to extract all substances as quantitatively as possible. However, for each solute to be extracted the optimum composition may be located in another region of the factor space there may be no such combination of mixture variables, that guarantees optimum extraction for all substances. 

Similar to the criterion of the minimal partition coefficient, one can also use the criterion of the minimal selectivity. This criterion (a , ) is defined as follows an extraction liquid composition is optimal if there is no other composition that gives a higher value for the minimal selectivity (maximise In other words the optimum composition is that... 

The design of reactors, preparation of catalysts, control of tempera-tim and other topics of practical importance are summarized by Pokrovskii in excellent reviews1 84.1885 which encompass the literature up to 13o5. Reference should be made to these sources for numerous patent disclosures that will not be considered in the present disoussicn Among the significant problems examined by Pokrovskii from the standpoint of industrial technology are relative merits of fixed and fluidized catalyst beds, optimum composition of the reaction mixture in terms of both yield and safety, and properties of catalysts—selectivity, activity, durability, etc,—that arc vita] to the success of the enterprise. 

The optimum HLB number for forming an emulsion depends to some extent on the nature of the particular system. Suppose that 20 per cent sorbitan tristearate (HLB 2.1) plus 80 per cent polyoxyethylene sorbitan monostearate (HLB 14.9) is the optimum composition of a mixture of these emulsifiers for preparing a particular O/W emulsion. The HLB of the mixture is, therefore, (0.2 x 2.1) + (0.8 x 14.9) — 12.3. The theory is that an HLB of 12.3 should be optimum for the... 

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