Big Chemical Encyclopedia

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

Articles Figures Tables About

Constraints, Theory application

These limitations of the theory suggest that a more general statistical theory is necessary if the artificial constraint that applicability is limited to situations where Ni(r ) < 1 is to be removed. In making such a theory, we retain the assumption that Ni(r is an average value given by Equation 5.22. However, we now explicitly introduce a binomial distribution to account for the variation from the mean number of antifoam entities associated with any given bubble size. [Pg.335]

It turns out that there is another branch of mathematics, closely related to tire calculus of variations, although historically the two fields grew up somewhat separately, known as optimal control theory (OCT). Although the boundary between these two fields is somewhat blurred, in practice one may view optimal control theory as the application of the calculus of variations to problems with differential equation constraints. OCT is used in chemical, electrical, and aeronautical engineering where the differential equation constraints may be chemical kinetic equations, electrical circuit equations, the Navier-Stokes equations for air flow, or Newton s equations. In our case, the differential equation constraint is the TDSE in the presence of the control, which is the electric field interacting with the dipole (pemianent or transition dipole moment) of the molecule [53, 54, 55 and 56]. From the point of view of control theory, this application presents many new features relative to conventional applications perhaps most interesting mathematically is the admission of a complex state variable and a complex control conceptually, the application of control teclmiques to steer the microscopic equations of motion is both a novel and potentially very important new direction. [Pg.268]

Combined principles of thermodynamics are widely utilized in assessing the performances of heat storage systems. Thermoeconomics further combines the thermodynamic principles with engineering economics to estimate the cost of exergy, and optimize the cost under various constraints. Although, Valero et al. (1989) tried to unify the thermoeconomic theories, the concepts and procedures may vary, and create ambiguity in practical applications (Szargut, 1990 Tsataronis, 1993 Erlach et al., 1999 Sciubba, 2003). [Pg.134]

In this section we examine this orthogonality constraint in order to evaluate its consequences for a theory of valence. Is it a substantive formal constraint on the type of model we may use does it restrict the type of physical phenomenon we can describe or is it simply a technical constraint on the method of calculation or what In fact we shall find that the strong orthogonality constraint is central to any orbital basis theory of molecular electronic structure. It has a bearing on the applicability of the model approximations we use, on the validity of most numerical approximations used within these models and (apart from the simplest MO model) has a dominant effect on the technical feasibility of the methods of solution of the equations generated by our models. Thus, it is of some importance to try to separate these various effects and attempt to evaluate them individually. [Pg.59]

Until recently, the theory did not allow the configuration of the positive state to be described, due to entry/exit DNAs interpenetration upon application of the positive constraint to the loop. A recent development [63] takes the DNA impenetrability into account and deals with the resulting DNA self-contacts, which were allowed to slide freely, following the needs of the energy minimization process. [Pg.59]

The Slater hull constraints are not directly applicable to existing approaches to pair-density functional theory because they are formulated in the orbital representation. Toward the conclusion of this chapter, we will also address A-representability constraints that are applicable when the spatial representation of the pair density is used. [Pg.449]

Abstract The theoretical basis for the quantum time evolution of path integral centroid variables is described, as weU as the motivation for using these variables to study condensed phase quantum dynamics. The equihbrium centroid distribution is shown to be a well-defined distribution function in the canonical ensemble. A quantum mechanical quasi-density operator (QDO) can then be associated with each value of the distribution so that, upon the application of rigorous quantum mechanics, it can be used to provide an exact definition of both static and dynamical centroid variables. Various properties of the dynamical centroid variables can thus be defined and explored. Importantly, this perspective shows that the centroid constraint on the imaginary time paths introduces a non-stationarity in the equihbrium ensemble. This, in turn, can be proven to yield information on the correlations of spontaneous dynamical fluctuations. This exact formalism also leads to a derivation of Centroid Molecular Dynamics, as well as the basis for systematic improvements of that theory. [Pg.47]

Problem formulations [ 1-3 ] for designing lead-generation library under different constraints belong to a class of combinatorial resource allocation problems, which have been widely studied. They arise in many different applications such as minimum distortion problems in data compression (11), facility location problems (12), optimal quadrature rules and discretization of partial differential equations (13), locational optimization problems in control theory (9), pattern recognition (14), and neural networks... [Pg.75]

Although factorial designs are very useful for studying multiple variables at various levels, typically they will not be applicable to cosolvent solubility studies because of the constraint that all of the components must add to 100%. Forthis reason, mixtures of experimental designs are typically used. The statistical theory behind mixture designs has been extensively published [81-85], There... [Pg.167]

Because of its simplicity the impulsive model is very appealing and frequently employed to model measured rotational state distributions (Dugan and Anthony 1987 Levene and Valentini 1987 Butenhoff, Car-leton, and Moore 1990). In most applications, however, it is necessary to incorporate at least one fit parameter or some dynamical constraints in order to obtain agreement with experimental results, for example, the equilibrium angle in the excited electronic state or the point at which the repulsive force vector intersects the BC-axis. The impulsive model is not an a priori theory. [Pg.253]


See other pages where Constraints, Theory application is mentioned: [Pg.227]    [Pg.534]    [Pg.378]    [Pg.50]    [Pg.2024]    [Pg.777]    [Pg.220]    [Pg.44]    [Pg.50]    [Pg.16]    [Pg.215]    [Pg.82]    [Pg.83]    [Pg.216]    [Pg.230]    [Pg.214]    [Pg.16]    [Pg.23]    [Pg.591]    [Pg.245]    [Pg.107]    [Pg.109]    [Pg.328]    [Pg.259]    [Pg.122]    [Pg.235]    [Pg.126]    [Pg.820]    [Pg.258]    [Pg.33]    [Pg.406]    [Pg.2]    [Pg.77]    [Pg.664]    [Pg.133]    [Pg.140]    [Pg.14]    [Pg.129]    [Pg.169]   


SEARCH



Applicability constraints

Applications theory

© 2024 chempedia.info