Effects of composition

At a given temperature, the value of the true, or thermodynamie, equilibrium eonstant, K, is independent of eomposition. Exeept in the speeial ease of extremely dilute solutions, values of the eoneentration 

In the composition range where the sea-island morphology was shown, the increase of the PEI concentration caused an increase in the PEI phase volume and a lowering of the 

In the composition range showing the nodular morphology, the increase in the PEI concentration increased the viscosity of the system and the PEI phase volume, thus reducing the rate of coalescence of the epoxy nodules in the late stage of spinodal phase separation. Smaller epoxy nodules, therefore, were formed at higher PEI concentration. 

In the composition range where the dual phase morphology was shown, the volume fraction of the PEI-rich phase increased with the increasing initial PEI content because the volume fraction of the PEI-rich phase at the onset point of secondary phase separation increases. 

4 Domain size of epoxy nodule within dispersed phase in dual phase system. c Volume fraction of dispersed phase. 

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Liquid-liquid equilibria are much more sensitive than vapor-liquid equilibria to small changes in the effect of composition on activity coefficients. Therefore, calculations for liquid-liquid equilibria should be based, whenever possible, at least in part, on experimental liquid-liquid data. 

Table 9. Effect of Composition on the Permeability of Various Gases Through VDC Copolymers ...

Fig. 3. Effects of composition on physical properties. A, acetyl B, butyryl C, cellulose. 1, increased tensile strength, stiffness 2, decreased moisture sorption 3, increased melting point 4, increased plasticizer compatibiUty 5, increased solubiUties in polar solvents 6, increased solubiUties in nonpolar...

Fig. 1. Effect of compositional variations on the dielectric properties of strontium titanate-barium titanate solid solutions. A, BaQ SrQ QTiO B,...

A trial-and-error procedure is required with any K-value correlation that takes into account the effect of composition. One cannot calculate K values until phase compositions are known, and those cannot be known until the K values are available to calculate them. For K as a function of T and P only, the DePriester charts provide good starting values for the iteration. These nomographs are shown in Fig. 13-14/7 andZ . SI versions of these charts have been developed by Dadyburjor [Chem. Eng. Prog., 74(4), 85 (1978)]. 

Mangipudi et al. [63,88] reported some initial measurements of adhesion strength between semicrystalline PE surfaces. These measurements were done using the SFA as a function of contact time. Interestingly, these data (see Fig. 22) show that the normalized pull-off energy, a measure of intrinsic adhesion strength is increased with time of contact. They suggested the amorphous domains in PE could interdiffuse across the interface and thereby increase the adhesion of the interface. Falsafi et al. [37] also used the JKR technique to study the effect of composition on the adhesion of elastomeric acrylic pressure-sensitive adhesives. The model PSA they used was a crosslinked network of random copolymers of acrylates and acrylic acid, with an acrylic acid content between 2 and 10%. 

Benkoski, J.J., Fredrickson, G.H. and Kramer, E.J., The effect of composition drift on the effectiveness of random copolymer reinforcement at polymer-polymer interfaces. Macromolecules (2001, in press). 

Eigelstein, H. C., and E. N. Skinner. The Effect of Composition on the Scaling of Iron-Chromium-Nickel Alloys Subjected to Cyclic Temperature Conditions, ASTM, STP No. 165 (1954). 

Graft copolymerization of methylmethacrylate onto paper wood pulp using ceric ammonium nitrate as the initiator has been studied. Different experimental conditions have been used, including both water and water-organic solvent systems. The effects of composition of the grafting medium and grafting temperature on the grafting process are examined. 

Table 8 Effect of Composition of TMTD Curing System on the Charpy Notched Impact Strength (ai<) for 85/15 and 80/20 PP/EPDM Blends...

Blackburn, G. A. and B. A. George, Studies Show Effects of Composition on Propane Refrigeration, Oil and Gas Journal, PennWell Publishing Company, p. 124, Feb. 26, (1979). A1 rights reserved. 

With regard to the effect of composition, ferrous metals fall into three broad categories ... 

Fig. 7.48 Effect of composition of alloy and deposit on corrosion, shown as weight loss (gcm ) against plotted points. (Shaded area shows most attack, i.e. >0-5gcm )" ...

In a previous section it has already been observed that high-strength 2000 and 7000 series alloys are sensitive to the presence of water vapour in corrosion fatigue tests. Stress-corrosion susceptibilities of these alloys in low temperature aqueous solutions and the effect of composition and heat treatment have been widely investigated . It is not surprising therefore that when subjected to corrosion fatigue in similar environments, substantial environmental effects can be observed particularly at low frequencies of less than 1 Hz and AA values above These environmental effects tend to be... 

Since the conditions of this test can be standardised fairly readily, it has also been used as a routine test in comparing different alloys of the same general kind in the course of studies of effects of composition on properties, as, for example, in the researches by Hanawalt, Nelson and Peloubet on the corrosion of magnesium... 

The time to perforation may be influenced considerably by the random occurrence of pits that happen to meet after starting from opposite sides of a sheet. This chance meeting of pits may be determined only to a slight extent by the composition of the material and, therefore, will interfere with observations of the effects of composition. 

Fig. 8-3. Curves showing the effect of composition on the intensities of the analytical lines in the silica-alumina system. Marked absorption and enhancement effects "are showm. (Courtesy of K. K. Scott, Determination of Major Elements in Clays by X-ray. Spectroscopy, Fall, 1956 Meeting, Refractories Division, American Ceramic Society.)...

Fig. I. Effect of pressure on the melting temperature of argon, (a) Pure argon, (b) argon-helium, (c) argon-hydrogen.Qualitative difference between curves (b) and (c) is due to the effect of composition on the liquid-phase fugacity of argon (M6).

Equations (35) and (36) constitute what is called the unsymmetric convention of normalization, because yt and y g° t0 unity in different ways. The asterisk serves as a reminder that the activity coefficient so designated is normalized in a manner different from the customary one. Separate notation for activity coefficients normalized according to Eq. (36) is psychologically useful because the effect of composition on y is radically different from that on y. 

In addition to deciding on the method of normalization of activity coefficients, it is necessary to undertake two additional tasks first, a method is required for estimating partial molar volumes in the liquid phase, and second, a model must be chosen for the liquid mixture in order to relate y to x. Partial molar volumes were discussed in Section IV. This section gives brief attention to two models which give the effect of composition on liquid-phase thermodynamic properties. 

The difficulties encountered in the Chao-Seader correlation can, at least in part, be overcome by the somewhat different formulation recently developed by Chueh (C2, C3). In Chueh s equations, the partial molar volumes in the liquid phase are functions of composition and temperature, as indicated in Section IV further, the unsymmetric convention is used for the normalization of activity coefficients, thereby avoiding all arbitrary extrapolations to find the properties of hypothetical states finally, a flexible two-parameter model is used for describing the effect of composition and temperature on liquid-phase activity coefficients. The flexibility of the model necessarily requires some binary data over a range of composition and temperature to obtain the desired accuracy, especially in the critical region, more binary data are required for Chueh s method than for that of Chao and Seader (Cl). Fortunately, reliable data for high-pressure equilibria are now available for a variety of binary mixtures of nonpolar fluids, mostly hydrocarbons. Chueh s method, therefore, is primarily applicable to equilibrium problems encountered in the petroleum, natural-gas, and related industries. 

So far, we have described the effect of pressure and temperature on the phase equilibria of a pure substance. We now want to describe phase equilibrium for mixtures. Composition, usually expressed as mole fraction x or j, now becomes a variable, and the effect of composition on phase equilibrium in mixtures becomes of interest and importance. 

FIGURE 28.24 Plots of Payne effect of composites filled with different contents of Mg(OH)2. (From Zhang, Q. et al J. Appl. Polym. Set, 94, 2341, 2004.)... 

Prosser, H. J., Groffman, D. M. Wilson, A. D. (1982). The effect of composition on the erosion properties of calcium hydroxide cements. Journal of Dental Research, 61, 1431-5. 

The design of this fish study centered on sample collection, preservation, preparation, analysis, and QA/QC. There was no discussion of the effect of compositing on the sample population. No description was given of statistical techniques to be applied to the data for reporting results and for comparison with action levels and future data. Unfortunately, the omission of a statistical framework during planning of the field study is the rule rather than the exception in hazardous waste investigations. 

Cortie, M., Xu, X. and Ford, M. (2006) Effect of composition and packing configuration on the dichroic optical properties of coinage metal nanorods. Physical Chemistry Chemical Physics, 8, 3520-3527. 

An important aspect is that of studying the effects of composition of the efectrolyte solution on the electrocapillary and capacitance curves. Identical curves are obtained for solutions of fluorides, sulfates, and certain other alkali metal salts having identical... 

Griffiths RW (1986) The differing effects of compositional and thermal buoyancies on the evolution of mantle diapirs. Phys Earth Planet Inter 43 261-273... 

Figure 2. Contour sensitivity analysis illustrating the effect of compositional changes on the response around the optimal formulation.

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