Optimization of parameters

The synthesis of the correct structure and the optimization of parameters in the design of the reaction and separation systems are often the single most important tasks of process design. Usually there are many options, and it is impossible to fully evaluate them unless a complete design is furnished for the outer layers of the onion. For example, it is not possible to assess which is better. 

Optimization of Parameters Control and Characterization Defects by Magnetic Particles. 

Stewart J J P 1989 Optimization of parameters for semlempirical wavefunctlons J. Comput. Chem. 10... 

Tliroughout this chapter and in Table 1 the inclusion of QM results as target data is evident, with the use of such data in the optimization of empirical forces fields leading to many improvements. Use of QM data alone, however, is insufficient for the optimization of parameters for condensed phase simulations. This is due to limitations in the ability to perform QM calculations at an adequate level combined with limitations in empirical force fields. As discussed above, QM data are insufficient for the treatment of dispersion... 

Figure 4.4. Optimization of parameters. The exponential equation (4.1) was fitted to the normalized data from Table 4.5.

C. The Rheodyne Model 7010 injection valve, equipped with a 20-pl loop, was switched to injection at the apex of the sample band, as observed on the refractive index detector. The complex kinetics of the production of mono-, di-, and tri-brominated glycols is shown in Figure 14. Optimization of parameters such as the flow rate of acid resulted in a 15% reduction in batch cycle time and eliminated the need for manual analysis and intervention to obtain a desired endpoint composition. 

The synthesis of the correct structure and the optimization of parameters in the design of the reaction and separation systems are often the most important tasks of... 

Stewart J (1989) Optimization of parameters for semiempirical methods. 1 method. J Comput Chem 10(2) 209-220... 

New methods can be created by automatic optimization of parameters during a trial run and all methods can be stored permanently in a non-volatile area of memory which is preserved even when the instrument is switched off. Some instruments provide a means of producing first and second derivatives of the titration curve (p. 243) which can be advantageous where the end-point is indistinct or there is more than one end-point to be detected. Titrators with a substantial amount of RAM incorporate what is in effect a dedicated microcomputer. 

Stewart, J. J. P., Optimization of Parameters for Semiempirical Methods I. Method , J. Comput. Chemistry, 10, 209 (1989a). 

Macromolecular diffraction data are rarely of sufficient quality and quantity to allow construction of atomic models that would obey basic stereochemistry just based on this optimization of parameters to data. The observation-to-parameter ratio is a key factor in optimization procedures. For the optimization of a crystallographic model. 

American scientists at LLNL have studied all aspects of scaling-up followed by optimization of parameters and it appears that TATB would be manufactured by them in future by following the TMHI route. However, a new method proposed by the UK scientists is still at the laboratory scale in UK. According to a recent report in the literature, ATK Thiokol, Inc, USA has performed considerable route development for an alternate TATB process starting with phloroglucinol via Scheme 2.1. 

J. P. Stewart, subsequently left Dewar s labs to work as an independent researcher. Stewart felt that the development of AMI had been potentially non-optimal, from a statistical point of view, because (i) the optimization of parameters had been accomplished in a stepwise fashion (thereby potentially accumulating errors), (ii) the search of parameter space had been less exhaustive than might be desired (in part because of limited computational resources at the time), and (iii) human intervention based on the perceived reasonableness of parameters had occurred in many instances. Stewart had a somewhat more mathematical philosophy, and felt that a sophisticated search of parameter space using complex optimization algorithms might be more successful in producing a best possible parameter set within the Dewar-specific NDDO framework. 

Sharma, A., Chunn, C. D., Rothmel, R. K. Unterman, R. (1991). Studies on bacterial degradation of polychlorinated biphenyls optimization of parameters for in vivo enzyme activity. In Abstracts of the 9lst General Meeting of the American Society for Microbiology, p. 284. Washington, DC, Q-48. 

It should be mentioned that by changing the conditions of electrochemical synthesis — such as nature of the alcohol, the purity of the metal used as anode, the nature and concentration of the conductive additive, the voltage (usually 30 — 110 V DC is applied), the temperature, and even the construction of the cell — one can significantly effect the process of the anodic dissolution or even change its mechanism. As it has already been mentioned, the electrochemical dissolution of iron in alifatic alcohols gives insoluble iron (II) alkoxides [1005], while in 2-methoxyethanol a soluble iron (HI) complex is obtained [1514], Another example is provided by tantalum dissolution in isopropanol while high-purity metal is rapidly dissolved anodically [1639], the one containing impurities is passivated. Therefore, it is quite clear that each synthesis requires careful study, optimization of parameters of electrochemical synthesis, and isolation and purification of final products. 

J.J.P. Stewart, Optimization of parameters for semiempirical methods V Modification of NDDO approximations and application to 70 elements. J. Mol. Model. 13, 1173-1213 (2007)... 

Optimization of parameters of these equations for a set of data from Ref. [30] yields values of kt = 9.5 x 10-4 min-1 and ]/k6ROOH0/k3 = 100 mol s1/2 kg 1. It may be of interest that the rate constant kj is more than 4 times higher than that for decomposition of tert-butyl hydroperoxide at 150 °C (2x 10-4min-1) (inert solvent). 

Additional work in progress includes optimization of parameters affecting the oxalate precipitation step this includes determination of the chloride concentration required to solubilize lead the oxalate ion concentration required for maximum americium recovery with minimum impurity precipitation precipitate aging and hydrogen ion concentrations that will minimize americium solubility yet maximize impurity solubilization. 

Westendorf, R.G. "Optimization of Parameters for Purge and Trap Gas Chromatography" presented at the 32nd Pittsburgh Conference on Analytical Chemistry and applied Spectroscopy Atlantic City, NJ March, 1981. 

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