46 research outputs found
Heterogeneous Batch Distillation Processes: Real System Optimisation
In this paper, optimisation of batch distillation processes is considered. It deals with real systems with rigorous simulation of the processes through the resolution full MESH differential algebraic equations. Specific software architecture is developed, based on the BatchColumn® simulator and on both SQP and GA numerical algorithms, and is able to optimise sequential batch columns as long as the column transitions are set.
The efficiency of the proposed optimisation tool is illustrated by two case studies. The first one concerns heterogeneous batch solvent recovery in a single distillation column and shows that significant economical gains are obtained along with improved process conditions. Case two concerns the optimisation of two sequential homogeneous batch distillation columns and demonstrates the capacity to optimize several sequential dynamic different processes. For such multiobjective complex problems, GA is preferred to SQP that is able to improve specific GA solutions
Alkali and Alkaline Earth Metal Compounds: Core-Valence Basis Sets and Importance of Subvalence Correlation
Core-valence basis sets for the alkali and alkaline earth metals Li, Be, Na,
Mg, K, and Ca are proposed. The basis sets are validated by calculating
spectroscopic constants of a variety of diatomic molecules involving these
elements. Neglect of correlation in K and Ca compounds will lead to
erratic results at best, and chemically nonsensical ones if chalcogens or
halogens are present. The addition of low-exponent functions to the K and
Ca basis sets is essential for smooth convergence of molecular properties.
Inclusion of inner-shell correlation is important for accurate spectroscopic
constants and binding energies of all the compounds. In basis set
extrapolation/convergence calculations, the explicit inclusion of alkali and
alkaline earth metal subvalence correlation at all steps is essential for K and
Ca, strongly recommended for Na, and optional for Li and Mg, while in Be
compounds, an additive treatment in a separate `core correlation' step is
probably sufficient. Consideration of inner-shell correlation energy in
first-row elements requires inclusion of `deep core' correlation
energy in K and Ca for consistency. The latter requires special CCVZ `deep
core correlation' basis sets. For compounds involving Ca bound to
electronegative elements, additional functions in the basis set are
strongly recommended. For optimal basis set convergence in such cases, we
suggest the sequence CV(D+3d)Z, CV(T+2d)Z, CV(Q+)Z, and CV5Z on calcium.Comment: Molecular Physics, in press (W. G. Richards issue); supplementary
material (basis sets in G98 and MOLPRO formats) available at
http://theochem.weizmann.ac.il/web/papers/group12.htm
Optimization of a Morphing Wing Based on Coupled Aerodynamic and Structural Constraints
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77091/1/AIAA-39016-101.pd
DONLP2 Short Users Guide
This paper gives a short introduction into the design and the usage of the nonlinear programming code DONLP2. Only information pertinent to the users of the AMPL interface is given here. A more detailed description of the internal organization of the code, e.g. for users which might want to modify the code according to their needs, can be obtained from the sites with provide source code, e.g. netlib in directory opt/donlp2. 1 INTRODUCTION DONLP2 implements a variant of the SQP-method. It is designed to solve problems of the general form NLP: f(x) ! = min x2\Omega ; (1.1) where \Omega = fx 2 IR n : h(x) = 0 2 IR p ; g(x) 0 2 IR m g: (1.2) (In the following description we assume\Omega 6= ; of course. If this does not hold, then the code will terminate near a stationary point of a penalty term constructed from the constraints, see below.) It is assumed that f; h and g are defined on a open superset of\Omega and two times continuously differentiable there. Given some regularit..
A Sqp Method For General Nonlinear Programs Using Only Equality Constrained Subproblems
In this paper we describe a new version of a sequential equality constrained quadratic programming method for general nonlinear programs with mixed equality and inequality constraints. Compared with an older version [34] it is much simpler to implement and allows any kind of changes of the working set in every step. Our method relies on a strong regularity condition. As far as it is applicable the new approach is superior to conventional SQP-methods, as demonstrated by extensive numerical tests
Numerical experiments with modern methods for large scale QP-problems
We describe the outcome of numerical experiments using three approaches for solving convex QP-problems in standard form 1 2 x T Bx + b T x ! = min ; A T x \Gamma a = 0 ; (0.1) x 0 ; namely the unconstrained technique of Kanzow [14], the bound constrained technique of Friedlander, Mart'inez and Santos [8] and the author's bound constrained quadratic extended Lagrangian [23]. These three methods solve (0.1) by a single unconstrained respectively bound constrained minimization. For our test purposes a test generator has been written which generates problems of this type with free choice of the condition number of the reduced Hessian, condition number of matrix of gradients of binding constraints and number of binding constraints. The exact solution is randomly generated. As a minimizer the new limited-memory BFGS-method (for bound constrained problems) of Byrd, Lu, Nocedal and Zhu [2] has been chosen. This allows using exactly the same minimization technology with exactly the ..