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Special valuing

The basic assumption is that the Langmuir equation applies to each layer, with the added postulate that for the first layer the heat of adsorption Q may have some special value, whereas for all succeeding layers, it is equal to Qu, the heat of condensation of the liquid adsorbate. A furfter assumption is that evaporation and condensation can occur only from or on exposed surfaces. As illustrated in Fig. XVII-9, the picture is one of portions of uncovered surface 5o, of surface covered by a single layer 5, by a double-layer 52. and so on.f The condition for equilibrium is taken to be that the amount of each type of surface reaches a steady-state value with respect to the next-deeper one. Thus for 5o... [Pg.619]

The MM+ force field uses special values for ihe bending force coii-sianis when Lhe aloins are in a Ihree- or fmir-niembered ring. [Pg.186]

Th c values of V I, V2, and V3, in keal/tnol, are listed in mmp-tor.txtfdbf). fhc MM+ force field uses special values for the torsional force constants when the atoms are in a four-member ring. [Pg.187]

Since Grignard reagents can easily be obtained from aryl halides, they are of special value in the s nthesis of many aromatic compounds, particularly as, for reasons already stated (pp. 270, 276), aromatic compounds cannot generally be prepared by means of ethyl acetoacetate and ethyl malonate. [Pg.284]

This is not the only method of forming tetrazo-compounds. Each amino-group of a diamine may be diazotised and coupled. Benzidine and its homologues, which ha e been utilised in this way, have a special value for the cotton dyer, as the shades produced are not only ery biilliant, but, unlike the maiorily of... [Pg.290]

Zinc diffusion produces slight dimensional changes, but the increase of thickness due to the addition of zinc is controllable and independent of the surface contours. This property which is common to most diffusion processes is of special value for the treatment of threaded parts and articles with intricate contours. [Pg.400]

If for certain values of a parameter A in the differential equation, the qualitative aspect of the solution (i.e., the phase portrait ) of the differential equation remains the same (in other words the changes are only quantitative) such values of A are called ordinary values. If however, for a certain value A = A0 this qualitative aspect changes, such a special value is called a critical or bifurcation value. [Pg.338]

It follows that for a special value of one parameter, the observed value of y is independent of the second parameter. This happens at Ii= a2/ai2 or I2 = -ai/ai2 any of these values determines y= a -aia2/ai2, the so called isoparametrical point. The argument can evidently be extended to more than two independently variable parameters. Experimental evidence is scarce. In the field of extrathermodynamic relationships, i.e., when j and 2 are kinds of a constants, eq. (84) was derived by Miller (237) and the isoparametrical point was called the isokinetic point (170). Most of the available examples originate from this area (9), but it is difficult to attribute to the isoparametrical point a definite value and even to obtain a significant proof that a is different from zero (9, 170). It can happen—probably still more frequently than with the isokinetic temperature—that it is merely a product of extrapolation without any immediate physical meaning. [Pg.473]

Alkylcatechols are important as chemicals and chemical intermediates in the fine chemistry industry for the synthesis of flavouring agents, agricultural chemicals and pharmaceuticals [1]. 3-methyl catechol has a special value from the industrial point of view. Previously y-alumina was found to be an effective catalyst for the gas-phase methylation of catechol with methanol [2]. The process can be schematically presented as ... [Pg.171]

The distinct advantage of marginal costing is that it helps the farmer to realise the absolute minimum he has to earn on his products. This is of special value when the farmer is selling directly at the farm gate. [Pg.117]

Thus, the family of azolides represents a versatile system of reagents with graduated reactivity, as will be shown in the following section by a comparison of kinetic data. Subsequent chapters will then demonstrate that this reactivity gradation is found as well for alcoholysis to esters, aminolysis to amides and peptides, hydrazinolysis, and a great variety of other azolide reactions. The preparative value of azolides is not limited to these acyl-transfer reactions, however. For example, azolides offer new synthetic routes to aldehydes and ketones via carboxylic acid azolides. In all these reactions it is of special value that the transformation of carboxylic acids to their azolides is achieved very easily in most cases the azolides need not even be isolated (Chapter 2). [Pg.15]

The Frobenius series can be shown not to converge forjx > 1. An important special case occurs when c = q = 1(1 + 1), l = 0,1,2,..., any non-negative integer. For each of these special values, one of the two chains of coefficients terminates at A because... [Pg.42]

The solution for T is rather similar to X with the constant c2A replacing A. Boundary conditions are used to select acceptable solutions from the infinite set. It can happen that one or more of these boundary conditions can be satisfied only when the separation constant takes on some special values. The subset so generated contains only permissible values, or eigenvalues, for the problem. The corresponding solutions are called eigenfunctions. [Pg.48]

Effective and simple immobilization of enzymes can be obtained by the cross-linking of enzyme aggregates, so-called CLEAs [55]. In this way, essentially any enzyme, including crude preparations, can be transformed into a heterogeneous type of material, insoluble in both water and organic solvents, that is stable and recyclable with high retention of the enzyme s original activity [56], These enzyme preparations are, therefore, of special value for both bio-bio and bio-chemo cascade processes. [Pg.293]

These differences are of special value for an estimation of the effects of branching. [Pg.136]

The petroleum ether solvents are a specific-boiling-range naphtha, as is ligroin. Thus, the term petroleum solvent describes a special liquid hydrocarbon fraction obtained from naphtha and used in industrial processes and formulations (Weissermel and Arpe, 1978). These fractions are also referred to as industrial naphtha. Other solvents include white spirit, which is subdivided into industrial spirit [distilling between 30 and 200°C (86 to 392°F)] and white spirit [light oil with a distillation range of 135 to 200°C (275 to 392°F)]. The special value of naphtha as a solvent lies in its stability and purity. [Pg.258]

The use of metals for prearranging reaction centers as neighboring groups has a special value in the production of macrocycles (template effect). Although these ligands can be sometimes prepared directly, the addition of metal ion during the synthesis will often increase the yield, modify the stereochemical nature of the product, or even be essential in the buildup of the macrocycle. There have been few mechanistic studies of these processes. The alkali and alkaline-earth metal ions can promote the formation of benzo[18]crown-6 in methanol ... [Pg.301]

In most cases the catalytically active metal complex moiety is attached to a polymer carrying tertiary phosphine units. Such phosphinated polymers can be prepared from well-known water soluble polymers such as poly(ethyleneimine), poly(acryhc acid) [90,91] or polyethers [92] (see also Chapter 2). The solubility of these catalysts is often pH-dependent [90,91,93] so they can be separated from the reaction mixture by proper manipulation of the pH. Some polymers, such as the poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymers, have inverse temperature dependent solubihty in water and retain this property after functionahzation with PPh2 and subsequent complexation with rhodium(I). The effect of temperature was demonstrated in the hydrogenation of aqueous allyl alcohol, which proceeded rapidly at 0 °C but stopped completely at 40 °C at which temperature the catalyst precipitated hydrogenation resumed by coohng the solution to 0 °C [92]. Such smart catalysts may have special value in regulating the rate of strongly exothermic catalytic reactions. [Pg.74]

The above and reports from other workers (awaiting publication at the time of writing), strongly suggest that this type of neuromuscular blocking agent constitutes a notable advance in anaesthesia. The properties of pancuronium, which make it of special value in the poor-risk or asthmatic patient may be briefly summarized as ... [Pg.15]

The isotope is of special value as a heat source to make... [Pg.24]

The use of FCIO3 chemical reagent for the introduction of fluorine or a CIO3 group has been discussed in detail in Section III, K, 4 and is of special value for the synthesis of fluorine-containing steroids. The polymerization of ethylene under a pressure of hundreds of atmospheres and a temperature of about 200°C in the presence of FCIO3 has been patented (135). [Pg.385]

As a fourth compound one might quote RuFs that was already assigned to the VFa-type. The fluorine parameter (x = —0.100) in this trifluoride deviates but slightly from the special value x = —... [Pg.40]

I believe I have already mentioned in my preceding letter that, several years before my trip to Vienna, perhaps in 1785 to 1786,1 had already worked with the so-called auro prohlematico which the late Mr. von Fichtel had sent here to my honored friend, Treasurer Siegfried, and that I was guided by the experiments which Mr. Miiller von Reichenstein had made and had described in the Physical Researches, and whose belief that it contains a new metal I found to be well grounded to which conclusion the beautiful criterion previously announced by M. v. R., the red color which this metal imparts to sulfuric acid, was also of special value. Several of my friends here and members of my1 audience at that time can and will testify to this. [Pg.333]

Predictably with an NP-rich product like wine, consumption is accompanied by ritual. Wines are served at official dinners, at weddings, to celebrate births and to show displays of triumph after car racing. Special drinking vessels (wine glasses), special storage containers (wine bottles), special storage racks and wine cellars, all point to wine having a special value in European culture. [Pg.54]

The efficiency of the golden section stems from the special value of the ratio i. We require the ratio of the larger of the two segments to the total length of the interval be the same as the ratio of the smaller to the larger segment,... [Pg.88]

Imagine the liquid to be divided into microscopic cells as shown in Fig. 22. The volume of a cell must be chosen carefully to have a particular, special value, described later. A cell is small enough so that occasionally it may be empty. At other times one or many molecules may occupy the cell. Consider all possible configurations of all the molecules in all the cells. The most probable configuration will exist for a large mass for a long time. In this respect the most probable distribution is a description of the steady-state condition. The problem is to calculate the most likely distribution. Once this is known, the rate of formation of any density in a cell can be calculated. [Pg.40]


See other pages where Special valuing is mentioned: [Pg.270]    [Pg.146]    [Pg.150]    [Pg.195]    [Pg.132]    [Pg.238]    [Pg.248]    [Pg.218]    [Pg.248]    [Pg.133]    [Pg.225]    [Pg.152]    [Pg.119]    [Pg.113]    [Pg.284]    [Pg.180]    [Pg.406]    [Pg.12]    [Pg.399]    [Pg.33]    [Pg.88]    [Pg.364]   
See also in sourсe #XX -- [ Pg.42 ]




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