Effect of Other Variables

The principal point of interest to be discussed in this section is the manner in which the surface tension of a binary system varies with composition. The effects of other variables such as pressure and temperature are similar to those for pure substances, and the more elaborate treatment for two-component systems is not considered here. Also, the case of immiscible liquids is taken up in Section IV-2. 

The rate coefficient is almost always dependent on temperature. However, it can be influenced by total pressure, in both gas and liquid systems, plus ionic strength and solvent in liquid systems. Following Fogler (1999), in the present book, the rate coefficient is considered to be a function of only temperature, assuming that the effect of other variables is much less. 

Operating temperatures on shelf-life, while eliminating the effect of other variables (such as encapsulating agent, solids concentration, and powder moisture content) on shelf-life. 

The effects of other variables such as polymer type, processing temperature, extrusion vs. milling, etc., have not been investigated but may be fruitful areas of exploration. 

The remainder of this book applies thermodynamics to the description of a variety of systems that are of chemical interest. Chapter 12 uses thermodynamics to describe the effects of other variables such as gravitational field, centrifugal field, and surface area on the properties of the system. Most of the focus of the chapter is on surface effects. The surface properties of pure substances are described first, including the effect of curvature on the properties of the surface. For mixtures, the surface concentration is defined and its relationship to the surface properties is described. 

Synthetically, the question of which product is formed from a given carbonyl compound, the pinacol or the alcohol, is obviously of great interest. We have already noted the critical importance of the proton-donating ability of the medium in this respect. Attention has turned to the effect of other variables on the pinacol/alcohol ratio. Formaldehyde can be reduced cleanly to ethylene glycol at an electrode composed of a special type of carbon, in a process of potential commercial significance50. Nonaka and coworkers have found that reduction of aldehydes proceeds more selectively to aldehydes at nickel-Teflon-silica gel composite electrodes51. Nonaka and coworkers have also shown that for aromatic... 

Effect of Other Variables Entrainment diminishes with higher tray spacing and increases with hole diameter [Kister and Haas, l. 

A classic example showing how added refinements can come into an analysis for optimum conditions is involved in the development of methods for determining optimum economic pipe diameter for transportation of fluids. The following analysis, dealing with economic pipe diameters, gives a detailed derivation to illustrate how simplified expressions for optimum conditions can be developed. Further discussion showing the effects of other variables on the sensitivity is also presented. 

The complexity of food effects on zinc absorption is illustrated by the studies of Sandstrom et al.(25,37,38) in which phytate, protein, calcium, zinc and other factors appear to have variable effects on zinc absorption. Although It appears certain that food interferes with zinc absorption, the effects of individual food substances are unknown and difficult to predict. Regardless of individual effects, zinc administration with food will complicate efforts to measure the effects of other variables on intestinal absorption. 

Thus, four types of products (often involving stereoisomers) may be formed in dione-olefin reactions. The situation is further complicated by the fact that product compositions show solvent and temperature-dependence 125) (effects of other variables have not been investigated) so that results from different laboratories have sometimes been at variance. Prediction of results is hazardous. 

Winyl polymerization as a rule is sensitive to a number of reaction variables, notably temperature, initiator concentration, monomer concentration, and concentration of additives or impurities of high activity in chain transfer or inhibition. In detailed studies of a vinyl polymerization reaction, especially in the case of development of a practical process suitable for production, it is often desirable to isolate the several variables involved and ascertain the effect of each. This is difficult with the conventional batch polymerization technique, because the temperature variations due to the highly exothermic nature of vinyl polymerization frequently overshadow the effect of other variables. In a continuous polymerization process, on the other hand, the reaction can be carried out under very closely controlled conditions. The effect of an individual variable can be established accurately. In addition, compared to a batch process, a continuous process normally gives a much greater throughput per unit volume of reactor capacity and usually requires less labor. 

The effects of other variables on Kd and pHso are very diverse. Typically the Xp decreases and PH50 increases when the initial concentration of metal cations increases, but a few examples of constant Kd up to very high initial concentrations have been also reported. Usually the Xd increases when the equilibration time increases. 

A quantitative method has been developed to separate free and graft copolymers in an ABS sample. The ABS powder is dispersed in MEK and then introduced into the cells of a preparative ultracentrifuge. After the reproducibility of the procedure was ascertained, the method was used to determine the grafting parameters of samples polymerized under specific conditions. This analytical technique is well suited to demonstrate how the grafting efficiency or grafting density is influenced by various polymerization conditions such as mercaptan content, monomer flow rate, emulsifier content, or polybutadiene content. The effects of other variables such as temperature, the initiator system, and characteristics of the polybutadiene latex can also be demonstrated. 

In view of the large effect of changes in air-fuel ratio on PNA emissions, care must be taken in studying the effects of other variables, such as fuel composition, to make sure that variation in air-fuel ratio does not mask the prime variable under investigation. 

The effects of other variables are somewhat simpler than the effect of L/D or pressure. For example, when the design feed rate increases, all costs go up however, the capital cost per kilogram of feed drops significandy. Thus, total costs per kilogram can be significantly cheaper in large plants than in small plants. The effects of other variables are also summarized in Tables 11-4 and 11-5. 

The objective of this measurement technique is to screen surfactants for their ability to decrease interfacial tension and thereby mobilizing trapped oil. If we confine ourselves to this objective, it is not sufficient to measure the interfacial tension between crude oil and formation water only. More relevant information can be obtained by measuring trends (for example temperature and concentration variations) in the effect of other variables. Using this technique to predict behavior in an oil bearing formation, where we deal with totally different processes, leads to the question what is the real value of measuring ultra low interfacial tension for predicting oil recovery in the reservoir ... 

Monodisperse copolymer particles from 1.1 to 2.6 micrometers in diameter were obtained by unseeded batch dispersion copolymerisation of styrene and butyl acrylate in an ethanol-water medium. A two-level factorial design using bottle polymerisations was initially carried ont including the following variables stabiliser concentration, initiator concentration, polarity of the dispersion medium, initial monomer concentration, and temperature. Once the region of experimental conditions in which monodisperse latexes can be prepared was identified, further effort was devoted to analyse the effect of other variables. 51 refs. 

F. Effect of Other Variables on the Inversion Line TV. Dynamic Phenomena in Emulsion Modification... 

Where the objective is to uncover the governing physics in the problem, the effects of the local dissipation must be separated from the effects of other variables. To accomplish this, geometric similarity will often not be maintained, and the best available scaling for the local dissipation is NpN D, or the power input per unit of impeller swept volume. 

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