Models, predictions based

In Figure 5.23 the finite element model predictions based on with constraint and unconstrained boundary conditions for the modulus of a glass/epoxy resin composite for various filler volume fractions are shown. 

Figure 4.17. Measured sticking probability (relative to the clean surface) of a methane molecular beam on Ni(l 11) surfaces with varying amounts of Au alloying into the surface. The result of a model (prediction) based on DFT calculations of the change in the activation energy due to the addition of Au atoms is also shown. The beam data primarily measures methane sticking on the facets. Adapted from Ref. [59].

Altogether, the data reported in this section indicate a very good predictive quality of the model simulations this implies in the first place that the SCR kinetics estimated over powdered catalyst were successfully validated at this bigger scale. However, the excellent agreement between monolith data and model predictions based on intrinsic kinetics also confirms the accurate model description of physical phenomena, specifically external and intraporous mass transfer, which were not significant in the microreactor runs over the powdered catalyst, but played an important role in the monolith runs, as pointed out by the direct comparison in Fig. 44. 

The various approaches to discriminate between models and to test a given model s adequacies have been treated above, and focus is given here on the design criterion A simple approach can be followed to determine the maximum divergence between model predictions Based on statistical considerations for two models, a simple expression was derived to measure the divergence D(x ) at the experimental settings x of the experimental grid... 

Fig. 18. Average fractional energy transfer of diretly scattered oxygen atoms as a function of deflection angle, x. for i i) = 47 kJ mol and 6i = 60° (circles). The dashed line is the hard-sphere model prediction based on the effective surface mass, ms, shown. The solid line is the revised prediction after the hard-sphere model is corrected for the internal excitation of the interacting surface fragment. The correction is derived from a kinematic analysis of scattering in the c.m. reference frame.

Titration curves may be misleading when the reagent and effluent reach an equilibrium pH on a time-scale comparable to or longer than the residence time in the treatment system. Unless the reactions involved are modeled, predictions based on the titration curve(s) may be quite inaccurate. The most common instance of this involves the use of calcium hydroxide reagents (slaked or hydrate lime), which is discussed below. If other slow reactions take place, considerable modeling effort may be needed, or very careful interpretation of results. 

The results are consistent with the Shawnee findings. Furthermore, the SO2 removal obtained at Springfield lay within 1 to 3 percentage points of model prediction based on the Shawnee data under similar operating conditions. 

Model predictions based on realistic thermophysical and thermochemical parameters (see Table 2) are also shown in Fig. 11 for both Eg 1 (Eg = 40 kcal/mol) and Eg 1 (Eg = 0). Both models exhibit exponential temperature profiles, Eg 1 concave-up and Eg 1 concave-down. At the surface, dT/dx is... 

Fig. 17 Temperature profile for HMX. Experimental data from Zenin [27]. Model predictions based on parameters in Table 2.

Several CD experimental runs were conducted with varying reflux flow rate and different amount of catalyst. The productions of DAA and MO were determined using gas chromatographic techniques. The experimental conditions and comparison of model predictions based on our recent three-phase non-equilibrium... 

Figure 21 shows model predictions based on Eq. (53) when X ranges from 0 to 5. It is seen that in general the heterogeneity effect does not seriously disturb the adsorption properties for values of X smaller than 2 - 3. It is also interesting to observe that the model predicts Frumkin s type adsorption isotherms even at high X values (Figure 21B). This may explain the validity ofthe Frumkin isotherm in a number of studies using solid polycrystalline electrodes of high hydrogen overpotential. ...

Fig. 3.6. Results of a kinetic experiment performed in batch mode and comparison with model predictions based on the kinetic approach suggested by Rehfinger and Hoffmann [11] ([18], reprinted from Chem. Eng Sci., Vol 57, Beckmann et al., Pages 1525-1530, Copyright 2002, with permission from Elsevier Science)...

Hogg et al. [7], Karra and Fuerstenau [8] and Abouzeid and Fuerstenau [11,29] carried out extensive experimental studies on solids flow in rotating drums with and without end constriction. Abouzeid and Fuerstenau gave empirical expressions for the drum fractional hold-up in terms of a dimensionless feed rate function. Their expression for the fractional hold-up was designed to cover a wide range of drum dimensionless rotational speed, 0 S n < 0.9. Unfortunately, their expressions of H in of their papers differ, and it was not possible to reconcile the two expressions [11,29], However, their experimental findings will be used to assess model predictions based on Equation 3. 

The reinforcing effect in the UDP MFC was assessed on the basis of the E and data from the stress-strain curves in comparison with the data of the neat HDPE matrix, or the model predictions based on Eqs. 14.1-14.4. 

ABSTRACT. We describe an apparatus by which the detonation products of an explosive can be identified and whose relative concentrations can be determined quantitatively. These measurements can be made on products that have been formed in less than one microsecond after the passage of the detonation wave. The technique is based on the rapid quenching of chemical reactions by virtue of the free expansion of the products into vacuum. Of course, products that have been formed over a longer period of time and under different pressure/temperature conditions can also be studied. Time resolved molecular-beam mass spectrometry is used, so that whether detonation occurred or not in forming the products can be determined. We describe optical techniques, principally Schlieren photographs, that also confirm detonation. We report measurements made on six standard explosives, PETN, RDX, HMX, HNS, TNT and TATB, and one research explosive, nitric oxide. For none of the standard explosives do we measure product distributions that agree with model predictions based on equilibrium assumptions. A computer model of the free expansion is described briefly and its importance to the interpretation of the data is emphasized. 

The effectiveness of gas-solid contact is reflected in the reactant conversions. Figure 10 shows the extents of reactant conversions in a bubbling bed reactor for various reactions as a function of dimensionless rate coefficients along with model predictions based on both the plug flow and the CSTR flow patterns for bubbling bed reactors (Kunii and Levenspiel, 1991). The conversions are typically lower than those predicted by either model, and this is an indication of inefficient gas-solid contact. 

The fifth parameter varied in this study was the type of pressurant gas. This parameter has implications on both LAD and pressurization subsystems as mentioned previously in Chapter 3. To determine the effect of pressurant gas type on the LAD subsystem, bubble point tests were conducted for the three different meshes across the same set of thermodynamic states of the liquid using both non-condensable (GHe) and autogenous GH2/ LH2) pressurization schemes. Results are plotted in Figures 5.15a-c and 5.16a-c for the 325 X 2300,450 x 2750, and 510 x 3600 screens in LH2 and LN2, respectively. All the bubble point data collected in this experiment from Figures 5.8 and 5.9 is thus plotted for comparison. Solid lines are again model predictions based on room temperature predictions. Error bars are plotted but are barely discernible. 

Figure 13. Reduced solubility parameter as a function of chain aspect ratio for the Ud = 0.5 SFC model and the analytic Gaussian thread model. Predictions based on two choices of polyethylene aspect ratio at 430 K arc shown. The liquid density is determined by the calibration procedure discussed in Ref. 52.

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