Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Details of the Modeling

All superparamagnetic beads with radius a and magnetic susceptibility x subject to a homogeneous external magnetic field B develop a dipole moment with identical orientation and strength. [Pg.414]

The dynamic Eq. (9.21) for particle velocity Vi can be written in reduced form [57]. It shows that the dynamics of the superparamagnetic filament depends on three characteristic numbers. One of them is the sperm number [Pg.415]

It determines the influence of the external magnetic field on the superparamagnetic filament. The number Bj compares dipolar to bending forces and it is proportional to the magnetoelastic number introduced in Refs [4, 73, 74]. An alternative dimensionless number for characterizing the influence of the magnetic field is the Mason number introduced in the literature on magnetorheological suspensions [75, 88], [Pg.415]

It is the ratio of frictional to magnetic forces and determines the behavior of the superparamagnetic filament when magnetic forces dominate over bending forces. Finally, a reduced spring constant [Pg.415]


The integral under the heat capacity curve is an energy (or enthalpy as the case may be) and is more or less independent of the details of the model. The quasi-chemical treatment improved the heat capacity curve, making it sharper and narrower than the mean-field result, but it still remained finite at the critical point. Further improvements were made by Bethe with a second approximation, and by Kirkwood (1938). Figure A2.5.21 compares the various theoretical calculations [6]. These modifications lead to somewhat lower values of the critical temperature, which could be related to a flattening of the coexistence curve. Moreover, and perhaps more important, they show that a short-range order persists to higher temperatures, as it must because of the preference for unlike pairs the excess heat capacity shows a discontinuity, but it does not drop to zero as mean-field theories predict. Unfortunately these improvements are still analytic and in the vicinity of the critical point still yield a parabolic coexistence curve and a finite heat capacity just as the mean-field treatments do. [Pg.636]

In particular we would like to treat some essential effects of fluctuations where we assume that, for example, thermal fluctuations exist and are localized in space and time. The effects on large lengths and long times are then of interest where the results are independent of local details of the model assumptions and therefore will have some universal validity. In particular, the development of a rough surface during growth from an initially smooth surface, the so-called effect of kinetic roughening, can be understood on these scales [42,44]. [Pg.861]

Based on this physical view of the reaction dynamics, a very broad class of models can be constructed that yield qualitatively similar oscillations of the reaction probabilities. As shown in Fig. 40(b), a model based on Eckart barriers and constant non-adiabatic coupling to mimic H + D2, yields out-of-phase oscillations in Pr(0,0 — 0,j E) analogous to those observed in the full quantum scattering calculation. Note, however, that if the recoupling in the exit-channel is omitted (as shown in Fig. 40(b) with dashed lines) then oscillations disappear and Pr exhibits simple steps at the QBS energies. As the occurrence of the oscillation is quite insensitive to the details of the model, the interference of pathways through the network of QBS seems to provide a robust mechanism for the oscillating reaction probabilities. [Pg.155]

Experimental data from Bech Nielsen s study is shown in Fig. 6 and Fig. 7. The data show that implanted 2H is found predominantly in bond-center sites. This qualitative conclusion can be drawn immediately from the raw channeling data, especially the 111 planar scans, and does not depend on the details of the model used to subsequently analyze the data in greater detail. Si—Si bonds run perpendicularly across the 111 planar channel. At zero tilt, a strong flux peak of planar channeled ions is focused on the bond centered site and causes the peak seen in the data at this angle. However, back-bonded sites are hidden in the wall of this channel, which is unusually thick and consists of two planes of atoms close together. Thus, the ion flux near the back-bonded sites is low when the tilt angle is small, hence the dip in nuclear reaction yield calculated for this site. Bech Nielsen (1988) found that this data pointed to there being a minority of the 2H... [Pg.220]

Here we want to report a few results of such simulations that, we believe, shed some light on the structure of water and aqueous solutions on metal electrodes, and that do not depend on the details of the model. As mentioned above, one cannot simulate an ensemble of water and ions because one would need too large an ensemble. Therefore most studies have been limited to pure water. While the various water models that have been employed differ in detail, they all predict an extended boundary region at the surface where the water structure differs from that in the bulk. [Pg.242]

In less frequent situations a more comprehensive analysis approach is used to analyze the structure as a whole. For example, a finite element analysis of an entire building may be performed. Obviously, the load path need not be predetermined when such global analysis methods are used. However, the load path is influenced by the type and level of detail of the modeling so that engineering judgment and experience are also necessary to achieve a safe and economical design,... [Pg.38]

An overview of the NRLT-SAC model will be given here with sufficient detail to understand the case study. Full details of the model and its mathematical formulation are given in [1],... [Pg.53]

Here, the densities of the gaseous and solid fuels are denoted by pg and ps respectively and their specific heats by cpg and cps. D and A are the dispersion coefficient and the effective heat conductivity of the bed, respectively. The gas velocity in the pores is indicated by ug. The reaction source term is indicated with R, the enthalpy of reaction with AH, and the mass based stoichiometric coefficient with u. In Ref. [12] an asymptotic solution is found for high activation energies. Since this approximation is not always valid we solved the equations numerically without further approximations. Tables 8.1 and 8.2 give details of the model. [Pg.172]

The evolution of cooperation is frequently analysed in terms of the repeated Prisoner s Dilemma game. Computer simulations show that the emergence of cooperation is a robust phenomenon. However, the strategy which eventually gets adopted in the population seems to depend sensitively on fine details of the modelling process, so that it becomes difficult to predict the evolutionary outcome in real populations. [Pg.65]

The number of published fuel-cell-related models has increased dramatically in the past few years, as seen in Figure 2. Not only are there more models being published, but they are also increasing in complexity and scope. With the emergence of faster computers, the details of the models are no longer constrained to a lot of simplifying assumptions and analytic expressions. Full, 3-D fuel-cell models and the treatment of such complex phenomena as two-... [Pg.441]

Details of the model as well as more comprehensive discussion of the various cases simulated have been published elsewhere [23-26] and only the highlights and the overall significance of the work are presented here. [Pg.113]

To provide the necessary data on NO, the entire SFR laser - OA absorption system was enclosed in a capsule and flown to an altitude of 28 kM for real time in situ measurements." Figures 7(a) and (b) show the OA spectrum of ambient air (at 28 kM) analyzed before sunrise and at local noon. The lack of NO before sunrise and large concentration of NO at room is clearly seen. Figure 8 shows a summary of all the data compiled on two such balloon flights. We see that the measurements provide 1) absolute concentration of NO and 2) its diurnal variation. Many of the details of the model proposed above are confirmed (see Ref. 11 for details). [Pg.187]

Einstein coefficient of absorption for the pump wavelength calculated as B 531 In(lO) / where c is the velocity of light and is Avogadro s number. Other details of the modeling may be found in reference 3. [Pg.193]

We use the physical concept of the dynamic melting model proposed by McKenzie (1985) for the situation where the rate of melting and volume porosity are constant and finite while the system of matrix and interstitial fluid is moving. This requires that the melt in excess of porosity be extracted from the matrix at the same rate at which it is formed (the details of the model are shown in Fig. 3 of McKenzie, 1985). [Pg.41]

Fig. 19. Reciprocal particlescattering factor of a tri-functional regularly branched molecule, soft sphere moder931, where the numbers denote the shells of branching (details of the model are shown in Fig. 24 a, u2 = (S2)... Fig. 19. Reciprocal particlescattering factor of a tri-functional regularly branched molecule, soft sphere moder931, where the numbers denote the shells of branching (details of the model are shown in Fig. 24 a, u2 = (S2)...
The below concepts are an extension of those in Chapter 3 of Hydrate Engineering (Sloan, 2000). Details of the model can be found in the work by Davies et al. (2006). Here, only the first, most-common method of depressurization is treated conceptually. [Pg.669]

Fig. 7.10. The positronium 13Si-23Si resonance curve, together with the Te2 calibration line. Details of the model fit to the experimental data can be found in Fee et al. (1993b). Fig. 7.10. The positronium 13Si-23Si resonance curve, together with the Te2 calibration line. Details of the model fit to the experimental data can be found in Fee et al. (1993b).
Eq. (4), frequency-dependent, such that the limit for a(w) in Eq. (8) becomes physically acceptable. Under conditions appropriate to the correct limit, the normalized real and imaginary parts of the complex permittivity and the normalized dielectric conductivity take on the form depicted in Fig. (1). Here, is the relaxation time in the limit of zero frequency (diabatic limit). Irrespective of the details of the model employed, both a(w) and cs(u>) must tend toward zero as 11 + , in contrast to Eq. (8), for any relaxation process. In the case of a resonant process, not expected below the extreme far-infrared region, a(u>) is given by an expression consistent with a resonant dispersion for k (w) in Eq. (6), not the relaxation dispersion for K (m) implicit in Eq. [Pg.4]


See other pages where Details of the Modeling is mentioned: [Pg.394]    [Pg.397]    [Pg.581]    [Pg.41]    [Pg.65]    [Pg.124]    [Pg.47]    [Pg.129]    [Pg.108]    [Pg.371]    [Pg.168]    [Pg.343]    [Pg.394]    [Pg.79]    [Pg.189]    [Pg.80]    [Pg.468]    [Pg.52]    [Pg.446]    [Pg.34]    [Pg.61]    [Pg.84]    [Pg.160]    [Pg.525]    [Pg.165]    [Pg.34]    [Pg.351]    [Pg.169]    [Pg.247]    [Pg.213]    [Pg.239]    [Pg.70]   


SEARCH



Detailed Models

Detailed modelling

Model details

© 2024 chempedia.info