Parametric calculations

It was shown in Ref. [5] that the arguments given above for the closed EGT cycles also hold good for open EGT cycles, but this analysis is not repeated here. Some simple parametric calculations were given to illustrate the increased thermal efficiency of practical open EGT cycles, corresponding to Fig. 6.8a-c. It was assumed that water injection was... 

The assumptions made by the various authors (viz. polytropic efficiencies, combustion pressure loss and temperature ratio, etc.) are all roughly similar to those used in the calculations of uncooled dry cycles. Some modest amounts of turbine cooling were allowed in certain cases [9] but the effect of these on the efficiency should not be large at max 250°C (see later for discussion of more detailed parametric calculations by some of these authors). 

Harvey et al. gave a parametric calculation of the thermal efficiency of this plant, as a function of turbine inlet temperature, the reformer pinch point temperature difference and the pressure level in the reformer (the compressor overall pressure ratio, r). 

To make the phase angle plot, we simply use the definition of ZGp(joo). As for the polar (Nyquist) plot, we do a frequency parametric calculation of Gp(jco) and ZGp(joo), or we can simply plot the real part versus the imaginary part of Gptjco).1 To check that a computer program is working properly, we only need to use the high and low frequency asymptotes—the same if we had to do the sketch by hand as in the old days. In the limit of low frequencies,... 

In this Chapter we describe the extension of the parametric model used for 4f" spectra to calculations of absorption and emission spectra for the 4f 15d configuration. We also illustrate how they can be applied to calculate other properties of interest, such as non-radiative relaxation rates. Finally, we discuss the relationship between parametrized calculations and other approaches, such as ab initio calculations. 

Duan et al. (2007) present an alternative approach to these ab initio calculations. They suggest that, rather than attempting to calculate the multitude of 5d energy levels directly, ab initio approaches could concentrate on producing useful parameter values for only the subset of terms in the parametrized Hamiltonian (see section 2) which cannot be experimentally determined. That is, the ab initio calculations could produce reliable values, for example, for the / (fd) and <7v(fd) parameters that could then be incorporated into parametrized calculations. The parameters may then be fine tuned to give a reliable calculation that might be used to investigate other properties of the ions, such as the non-radiative relaxation discussed in section 3.4. 

Based on the reference case, parametric calculations were conducted specifying the actuation condition and time of isolation valves as a parameter. Table 2 shows the actuation times of isolation valves, calculation results of secondary cooling system isolation time and amount of helium gas transportation from primary to secondary. 

Caltech unified GCM (Global) Bulk equilibrium, ZSR equation, no hysteresis None Autoconversion nucl. scavenging with prescribed scavenging coefficient for sea-salt and dust and a first-order precipitation-dependent parametrization for other aerosols precip. rate independent of aerosols First-order precipitation-dependent bulk parametrization calculated scavenging efficiency with size dependence Implicitly accounted for in a parametrization of the limiting autoconversion rate... 

Dynamic Response Functions. - The perturbation series formula or spectral representation of the response functions can be used only in connection with theories that incorporate experimental information relating to the excited states. Semi-empirical quantum chemical methods adapted for calculations of electronic excitation energies provide the basis for attempts at direct implementation of the sum over states (SOS) approach. There are numerous variants using the PPP,50,51 CNDO(S),52-55 INDO(S)56,57 and ZINDO58 levels of approximation. Extensive lists of publications will be found, for example, in references 5 and 34. The method has been much used in surveying the first hyperpolarizabilities of prospective optoelectronically applicable molecules, but is not a realistic starting point for quantitative calculation in un-parametrized calculations. 

The most extensive systematic determination of 4f parameters for ions across the lanthanide series is by Carnall et al. (1988, 1989) for lanthanides in LaFs. The 4f free ion parameters are reduced by a few percent in crystals relative to gaseous ions, but do not change very much from one crystalline environment to another. For this reason, the tabulations of Carnall are still used as the starting point for many of the parametrized calculations within the 4f shell. In most cases, the energy level data are not sufficiently complete to unambiguously determine all of the free ion parameter values, so some of the parameters, such as the three-body parameters, r, are often kept fixed at Carnall s values. The determination of exactly which parameters to keep fixed, and which to vary, is usually decided on a case-by-case basis, based upon how many multiplets are covered by the data, and upon the indeterminacies that arise during the fitting process itself. 

In general, it is recommended that parametric calculations be performed for the key factors. This sensitivity analysis should cover at least the following parameters ... 

A computer algorithm has been formulated from ah analytical method which transforms without approximation the general form of the two-dimensiohal (2-D) transport equation into a diffusion-like differential equation. The computational. economy of this procedure is demonstrated in the application of the technique ta the parametric calculations required in determining fuel storage pool -eigenvalues as a function of fuel assembly spacing. 

Some more rigorous, non-parametric calculations also confirm the validity of the isolobal principle. Fenske-Hall LCAO-MO-SCF calculations of the structure of B5H9 and some of its ferroborane derivatives, i.e. l-Fe(CO)3B4Hs, 2-Fe(CO)3B4Hs and l,2-[Fe(CO)3]2B3H3 have been completed. A summary of a qualitative description of the properties of frontier molecular orbitals in... 

To ensure that the remaining QM and MM atoms interacted correctly across the covalent interface. Field et al performed a series of parametrization calculations on model compounds [17]. They found that the same covalent MM and... 

In addition, stand-alone parametric calculations were performed which confirmed the order of magnitude of the APRIL-calculated melting rates of the upper vessel internals due to heat radiation from the d aded and partially molten reactor... 

Parametric calculations were performed to examine the relationship between the steam temperature in the upper plenum and the leadscrew temperatures deduced from the TMI-2 leadscrew material samples as described in Reference 5. The steam temperature calculated in this fashion can be compared with that predicted by the codes to detect any inconsistency. 

Barakat et al. [8] have photographed the Pd III spectrum emitted by a sliding spark in the 450 to 2300 A region with a 6.65 m normal incidence vacuum spectrograph. They have found all the missing levels of the 4d , 4d 5s, and 4d 5p configurations with the aid of Hartree-Fock and parametric calculations and listed 326 newly classified lines between 611 and 2285 A. 

It is planned to extend the capabilities of reactor parametric calculations of the computer-based system to include the following additional reactor parameters. 

---