To obtain a meaningful comparison of Eq. (6) with experimental data and to measure Vs, consider the slope dV/dJj aiV= Vx and JT = 0, which is [Pg.43]

Measurement of as a function of the log of JK gives a value for / , and a plot of dV/dJT at V= Vx as a function of J l will give a value for V%. However, experimentally it is more convenient to measure JK and derive Vs from a plot of dV/dJr at V = Vx versus such as shown in Fig. 4 for a test [Pg.43]

The relationship in Fig. 4 is linear, with the intercept on the y-axis equal to [Pg.43]

To simplify further analysis it is assumed that 7 c = 0. A geometric representation of Vs, V, AV, and dV/dJT at V=Voe in relation to the I-V characteristic is shown in Fig. 5 for the simplified case of Rc = 0. The value for JK/JP is determined as a function of Vs by setting the terminal voltage in Eq. (6) equal to zero, and, with the values of / and experimentally derived, solving the transcendental equation. With application of the results toEq. (10), V is plotted as a function of Vs as shown in curve A, Fig. 6, where / = 1.56 and FOC = 850 mV. [Pg.44]

One valuable approach to quantify the effects of diffusion (or mobility restrictions) on the cure kinetics is via direct estimation of a diffusion factor, DF. The latter is defined as the ratio of the experimentally measured conversion rate (dx/d/)obs over the predicted conversion rate at the same reaction conversion x in the absence of mobility restrictions (dx/d/)kin [Pg.129]

The left-hand-side part of this equation (dx/dt)obs is proportional to the non-reversing heat flow according to Eq. (8). For step-growth polymerisation reactions, diffusion control is governed by the vitrification process (section 5.1.1). Therefore, as a first approximation, the normalised heat capacity signal or mobility factor, DF, [Eq. (10)] is proposed to be an in [Pg.129]

The empirical rate equation proposed by Kamal [38] is applied for the chemically controlled reaction rate of any epoxy resin cure showing auto-catalytic behaviour [Pg.130]

The temperature dependence of any rate constant is given by an Arrhenius relationship [Pg.130]

The phenomenological rate constant kin(, 7 ) describes the overall chemically controlled polymerisation reaction and is incorporating an increase in value due to auto-catalysis. Combining Eq. (11) and Eq. (14) results in [Pg.130]

Employing the proposed model, the behavior of the experimental signals of Cu, Ag, and Zn at different temperatures was described. The model explains increased tailing of the back edge of Cu profiles. [Pg.105]

The quantitative computations were conducted using equilibrium thenuodynamic model. The proposed model for thermochemical processes divides layer of the sample into contacting and non-contacting zones with the material of the atomizer. The correlation of all initial components in thermodynamic system has been validated. Principles of results comparison with numerous experimental data to confirm the correctness of proposed mechanism have been validated as well. [Pg.414]

semi-quantitative agreements are found in diffraction patterns and proposed models obtained by molecular-dynamics[14], because the results of the ex-periments[31-34] are consistent with the atomic models proposed by us[14]. However, in the present state of high-resolution electron microscopy, taking into account, moreover, the number of sheets and the complicated geometry of the helix, it seems unlikely to directly visualize the pentagon-hexagon pairs. [Pg.84]

Based on the modification studies of this chapter, the potential reactants in the proposed model of important factors described in Fig. 6.1 must certainly be considered to be in a different configuration in terms of morphology and relative position than in the starting configuration. [Pg.171]

However, one should emphasize that the proposed model of the interactions does not exclude a possibility of the formation of higher-order associates. On average, the concentration of trimers and higher-order mers is about 8% in the case of systems presented in Fig. 20. Thus, the presence of associates larger than dimers does not prevent the applicability of the... [Pg.236]

The sense of this procedure may be verified in Figure 4.13. An implicit assumption in this procedure is that the speed at which the sources are activated equals the speed at which the activation zone is propagated. This holds only if the flame propagates into a quiescent mixture, which does not really happen. Computational experiments with the proposed model show that this assumption is increasingly justified as a cloud s aspect ratio increases. [Pg.97]

An artificial neural network based approach for modeling physical properties of nine different siloxanes as a function of temperature and molecular configuration will be presented. Specifically, the specific volumes and the viscosities of nine siloxanes were investigated. The predictions of the proposed model agreed well with the experimental data [41]. [Pg.10]

A list of the systems investigated in this work is presented in Tables 8-10. These systems represent 4 nonpolar binaries, 8 nonpolar/polar binaries, and 9 polar binaries. These binary systems were recognized by Heil and Prausnitz [55] as those which had been well studied for a wide range of concentrations. With well-documented behavior they represent a severe test for any proposed model. The experimental data used in this work have been obtained from the work of Alessandro [53]. The experimental data were arbitrarily divided into two data sets one for use in training the proposed neural network model and the remainder for validating the trained network. [Pg.20]

Fig. 3. A proposed model for 1 1 complex of [18]aneN6 3 H+ with citrate 49>... |

The proposed model of the structure of oxyfluoride melts corresponds with the conductivity results shown in Fig. 69. The specific conductivity of the melt drops abruptly and asymptotically approaches a constant value with the increase in tantalum oxide concentration. This can be regarded as an additional indication of the formation of oxyfluorotantale-associated polyanions, which leads to a decrease in the volume in which light ions, such as potassium and fluorine, can move. The formation of the polyanions can be presented as follows ... [Pg.167]

PA at l. 48 eV appeal s instantaneously, shows spectral relaxation to the red, and decays on the same timescale of SE, as shown in Figure 8-9. We assign the observed PA to singlet Bu exciton transitions towards higher lying even parity (A ) states. We can speculate on the nature of this state within the proposed model. A possible candidate for the final slate is the inirachain biexciton. However, its energy level is located below the two-exciton stale by an amount equal to the bind-... [Pg.450]

It should be noted that the sense of asymmetric induction in the lithiation/ rearrangement of aziridines 274, 276, and 279 by treatment with s-butyllithium/ (-)-sparteine is opposite to that observed for the corresponding epoxides (i.e. removal of the proton occurs at the (S)-stereocenter) [102], If one accepts the proposed model to explain the selective abstraction of the proton at the (R) -stereo-center of an epoxide (Figure 5.1), then, from the large difference in steric bulk (and Lewis basicity) between an oxygen atom and a tosyl-protected nitrogen atom, it is obvious that this model cannot be applied to the analogous aziridines. [Pg.178]

Figure 6.8 Rationale for enantioselection in Mn-salen epoxida-tion. a) Initially proposed model (the axial ligand L is omitted for clarity), b) Recently proposed model based on calculation. |

Within the framework of the proposed model, the ion exchange equilibrium between the solution and CP ion exchanger can be described by the equation ... [Pg.18]

In reality, oxygen concentration never reaches the concentration defined in the proposed model, since the microbial activities at optimal and maximum cell density would reach the point where oxygen depletion takes place.5... [Pg.45]

This equation, however, does not adequately represent the experimental data when used to correlate measured values of k0, Ag and Qx. It was modified empirically, but the modified equation does not account for observed variations of conversion with bed height and pressure. The proposed model would therefore appear to rest on oversimplified assumptions. [Pg.83]

In the proposed model, the total volume of the dispersion (or of the reactor) is subdivided into many subvessels (or subreactors). In each, Gal-Or and Hoelscher considered a fraction of the total number of bubbles having a radius between a and a + da. The distribution of bubbles in the subreactors... [Pg.363]

Where large samples of reactant are used and/or where C02 withdrawal is not rapid or complete, the rates of calcite decomposition can be controlled by the rate of heat transfer [748] or C02 removal [749], Draper [748] has shown that the shapes of a—time curves can be altered by varying the reactant geometry and supply of heat to the reactant mass. Under the conditions used, heat flow, rather than product escape, was identified as rate-limiting. Using large ( 100 g) samples, Hills [749] concluded that the reaction rate was controlled by both the diffusion of heat to the interface and C02 from it. The proposed models were consistent with independently measured values of the transport parameters [750—752] whether these results are transfenable to small samples is questionable. [Pg.171]

Numerical simulations. Locate one research publication that makes use of the kinsim program, by tracing Ref. 30 in Science Citation Index. Examine the data to check the match between experiment and model. In particular, study the differences between the results and those expected for a simpler kinetic system to ascertain why the complex treatment was needed. Report on how well the proposed model accounts for the complications. [Pg.123]

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