Variables ratio

Appreciable property differences appear between crude oils as a result of the variable ratios of the crude oil components. For a refiner dealing with crudes of different origins, a simple criterion may be established to group crudes with similar characteristics. Crude oils can be arbitrarily classified into three or four groups depending on the relative ratio of the hydrocarbon classes that predominates in the mixture. The following describes three types of crudes ... 

Phthalic anhydride, a polyol, and an unsaturated fatty acid are usually copolymerized to unsaturated polyesters for coating purposes. Many other combinations in variable ratios are possible for preparing these resins. The 1998 U.S. production of polyesters was approximately 1.7 billion pounds. 

Boiler FW is comprised of variable ratios of returned condensate and a MU water source. The MU requirement is proportional to the sum of nonrecoverable steam and BW blowdown that is lost from the plant. 

Thiamine is present in cells as the free form 1, as the diphosphate 2, and as the diphosphate of the hydroxyethyl derivative 3 (Scheme 1) in variable ratio. The component heterocyclic moieties, 4-amino-5-hydroxymethyl-2-methylpyrimidine (4) and 4-methyl-5-(2-hydroxyethyl)thiazole (5) are also presented in Scheme 1, with the atom numbering. This numbering follows the rules of nomenclature of heterocyclic compounds for the ring atoms, and is arbitrary for the substituents. To avoid the use of acronyms, compound 5 is termed as the thiazole of thiamine or more simply the thiazole. This does not raise any ambiguity because unsubstituted thiazole is encountered in this chapter. Other thiazoles are named after the rules of heterocyclic nomenclature. Pyrimidine 4 is called pyramine, a well established name in the field. A detailed account of the present status of knowledge on the biosynthesis of thiamine diphosphate from its heterocyclic moieties can be found in a review by the authors.1 This report provides only the minimal information necessary for understanding the main part of this chapter (Scheme 2). 

Atom-bonding state sp2 only sp only sp2, sp, sp (variable ratio)... 

All of the above essential elements, in non-stoichiometric and maybe somewhat variable ratios, are necessary for structure, energy capture, catalysis, coding, osmotic and electrolyte stability, and confinement in space... 

Treatment of bicyclopropylidene (1) with lithium powder led to ring opening and subsequent treatment of the reaction mixture with dimethyl sulfate afforded the methylenecyclopropane derivative 225 and 4-octyne (226) in variable ratios (Scheme 51) [143]. 

In the case of unsaturated chloramines 209, the DTBB-catalyzed lithiation had to be carried out in the presence of the electrophile in THF at —78 °C in order to avoid decomposition of the corresponding functionalized organolithium intermediate through elimination reactions. Final hydrolysis yielded a mixture (variable ratios 11.5/1 to 1/19 depending on the electrophile) of the a- and y-products 210 (Scheme 72) . ... 

Very interesting results were obtained from the reaction of magnesium alkylidene carbenoids with mefa-substituted arylamines (Table 8) . The reaction of magnesium alkylidene carbenoids 157 and 161 with three mefa-substituted anilines was carried out and the results are summarized in Table 8. The reaction of 157 with meta-anisidine gave two products 163 and 164 (in a 30 13 ratio) in 43% yield. The main product was found to have the alkenyl group at the more hindered position (163). As shown in the Table, all the other meto-substituted aniline derivatives also gave the more hindered alkenylated compounds as the main product in variable ratio. 

A main drawback of the Reformatsky reaction resides in the poor control of simple diastereoselectivity, resulting in variable ratios of syn and anti /3-hydroxyesters (equation... 

The animal can allocate between 0 and 100 percent of its time to the two activities. One is rewarded by a VR (variable-ratio) mechanism this is the one-armed bandit. The other is rewarded by a VI (variable-interval) mechanism this is the mechanism... 

The use of molecular mechanics as an aid in the interpretation of spectroscopic data is outlined in more detail in Chapter 9. One of the most rapidly developing applications of molecular mechanics is the use of the structures to aid in the analysis of multidimensional NMR spectroscopy125,261. This is particularly pertinent to the study of metal-macromolecule interactions where the spectroscopic data often have too low an observation/variable ratio to allow an unequivocal determination of the structure. Therefore, an additional source of structural information is needed. To date, there have been a limited number of studies involving metal ions but this area is likely to become a very important application of structural information from molecular mechanics studies (see also Chapter 9). 

In a limited sense solutions are homogeneous liquid phases consisting of more than one substance in variable ratios, when for convenience one of the substances, which is called the solvent and may itself be a mixture, is treated differently from... 

Interestingly, the two methods published for quantification of sunitinib used either HPLC [114] or UPLC [113] but the analytical time periods were of similar duration (run time of 3 min and 4 min, respectively). Of note, we observed during the course of our own method development [122] the presence of two peaks with the same molecular mass/signal transition for sunitinib, which, to the best of our knowledge, has not been reported elsewhere [113, 114, 123], The phenomenon was known, however, and is due to a Z-E isomerization reaction of sunitinib [124], Previous studies by the sunitinib manufacturer have shown that E isomer can be generated from the Z isomer in a reversible manner in solution [124], The rate of interconversion between the Z-E configurations in solution is dependent on a number of factors, most notably exposure to light. In our studies [122], we found that both isomers could be detected in the pharmaceutical preparation (tablet) at ratios of about 1 2, as well as in patients plasma samples (variable ratios). 

There are many variants in drug discrimination methodology whereby small procedural differences (fixed or variable interval instead of fixed or variable ratio reinforcement, probe trials with or without... 

In geochemical analysis the concentration range of an analyte often spans several orders of magnitude, and dilutions are frequently required to bring the sample solution within the calibration range. An automatic variable-ratio diluter is essential for this purpose. Many manufacturers produce suitable models, but corrosion problems are almost inevitable with the acidic solutions which are regularly used. Small amounts of acid can escape between the piston and the barrel, and cause corrosion, especially where metal parts are enclosed. 

A limited number of organic substances with two lattices is also known all columnar misfit structures. The crystal structure of hepta(tetrathiofulvalene)-pentaiodide, (TTF)7l5, determined by Johnson and Watson is one of the best described. [The substructures of the two components (TTF and iodine) were also determined - but in projection only - by Daly and Sanz ] In it, columns of TTF molecules form a matrix, the channels within which are filled by rows of iodine atoms. The 7 5 ratio of subcell multiplicities is only approximate within about 1% of the true ceD value. Similar structures have been determined for (TTF)Br , with a variable ratio of component subcells... 

In a limited sense solutions are homogeneous liquid phases eonsisting of more than one substanee in variable ratios, when for eonvenienee one of the substanees, whieh is ealled the solvent and may itself be a mixture, is treated differently from the other substanees, whieh are ealled solutes [1], Normally, the eomponent whieh is in exeess is ealled the solvent and the minor eomponent(s) is the solute. When the sum of the mole fraetions of the solutes is small eompared to unity, the solution is ealled a dilute solution A solution of solute substanees in a solvent is treated as an ideal dilute solution when the solute aetivity eoeffieients y are elose to unity (y=l) [1, 171], Solute/solvent mixtures A+ B that obey Raoult s law over the entire eomposition range from pure A to pure B are ealled ideal solutions. Aeeording to Raoult, the ratio of the partial pressure of eomponent AljpfO to its vapour pressure as a pure liquid (p ) is equal to the mole fraetion of A xa) in the liquid mixture, i.e. xa = Pa/Pa- Many mixtures obey Raoult s law very well, partieularly when the eomponents have a similar moleeular strueture e.g. benzene and toluene). 

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