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Structural Optimization (structural + optimization)
Selected AbstractsDecomposition and parallelization strategies for solving large-scale MDO problemsGAMM - MITTEILUNGEN, Issue 2 2007M. Grauer During previous years, structural optimization has been recognized as a useful tool within the discriptines of engineering and economics. However, the optimization of large-scale systems or structures is impeded by an immense solution effort. This was the reason to start a joint research and development (R& D) project between the Institute ofMechanics and Control Engineering and the Information and Decision Sciences Institute within the Research Center for Multidisciplinary Analyses and Applied Structural Optimization (FOMAAS) on cluster computing for parallel and distributed solution of multidisciplinary optimization (MDO) problems based on the OpTiX-Workbench. Here the focus of attention will be put on coarsegrained parallelization and its implementation on clusters of workstations. A further point of emphasis was laid on the development of a parallel decomposition strategy calles PARDEC, for the solution of very complex optimization problems which cannot be solved efficiently by sequential integrated optimization. The use of the OptiX-Workbench together with the FEM ground water simulation system FEFLOWis shown for a special water management problem. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Coherence of Structural Optimization and Configurational MechanicsPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2006Daniel Materna This contribution is concerned with the similarities of structural optimization and configurational mechanics. In structural optimization sensitivity analysis is used to obtain the sensitivity of continuum mechanical functions with respect to variations of the material body, i.e. the reference configuration. In the same manner in configurational mechanics we are interested in changes of the material body, e.g. crack propagation or phase transition problems. Consequently, variational design sensitivity analysis and the numerical techniques from structural optimization are applicable to problems fromconfigurational mechanics. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] ChemInform Abstract: Structural Optimization of Enantiopure 2-Cyclialkylamino-2-aryl-1,1-diphenylethanols as Catalytic Ligands for Enantioselective Additions to Aldehydes.CHEMINFORM, Issue 49 2008Sergi Rodriguez-Escrich Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Computational studies of the cone and 1,2,3 alternate calix[6]arene bis-crown-4 isomers: structures, NMR shifts, atomic charges, and steric compressionJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 12 2009Meghan N. Lawson Abstract The cone and 1,2,3 alternate isomers of calix[6]arene bis-crown-4 were investigated computationally. Structural optimizations, energies, bond distances, and Mulliken charges were calculated by the application of the B3LYP/6-31g(d) method/basis, followed by NMR calculations via both B3LYP/6-31g(d) and HF/6-31g(d). Calculations were completed at three different levels of imposed symmetry, and two calculations investigated the chloroform solvent effects. Better NMR results were obtained from HF/6-31g(d) calculations that did not impose molecular symmetry constraints. Consideration of solvent effects improved ground state energies, but other improvements were minimal and not significant enough to justify the added computational expense of solvent calculations. Overall results are consistent with known experimental assignments and were valuable for assigning previously unknown NMR peaks. Net charges, electrostatic forces, and local dipoles , but not bond lengths , are strongly correlated to spectroscopic manifestations of steric compression. Copyright © 2009 John Wiley & Sons, Ltd. [source] Development of New Pyrrolocoumarin Derivatives with Satisfactory Fluorescent Properties and Notably Large Stokes ShiftsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 36 2008Lei Chen Abstract Small, organic, fluorescent molecules with large Stokes shifts and long emission wavelengths are ideal dyes for various modern fluorescent imaging technologies such as FRET. In this study, we designed and synthesized a number of new fluorescent molecules on the basic structures of two pyrrolocoumarin skeletons where Fischer's indole synthesis and the Suzuki coupling successfully served as the efficient molecular editing protocols. The examination of the fluorescent properties and further structural optimization of these compounds afforded three new pyrrolocoumarin dyes with notably large Stokes shifts and satisfactory fluorescent properties. Among these, 30 showed a large Stokes shift (113 nm) and intense fluorescence (, = 0.55, ,em = 523 nm), and thus showed great potential in biological imaging studies. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Operational and structural optimization of multi-carrier energy systemsEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 5 2006Martin Geidl Abstract This paper presents an approach for the combined optimization of energy systems including multiple energy carriers such as electricity, natural gas, and district heat. Power flow and conversion between the different energy infrastructures are described as multi-input multi-output coupling, what enables simple analysis and optimization of the flows. While previous work deals with operational optimization (multi-carrier optimal dispatch and power flow), this paper focuses on optimization of the couplings between the different networks, that is the structure of the system. Copyright © 2006 John Wiley & Sons, Ltd. [source] Decomposition and parallelization strategies for solving large-scale MDO problemsGAMM - MITTEILUNGEN, Issue 2 2007M. Grauer During previous years, structural optimization has been recognized as a useful tool within the discriptines of engineering and economics. However, the optimization of large-scale systems or structures is impeded by an immense solution effort. This was the reason to start a joint research and development (R& D) project between the Institute ofMechanics and Control Engineering and the Information and Decision Sciences Institute within the Research Center for Multidisciplinary Analyses and Applied Structural Optimization (FOMAAS) on cluster computing for parallel and distributed solution of multidisciplinary optimization (MDO) problems based on the OpTiX-Workbench. Here the focus of attention will be put on coarsegrained parallelization and its implementation on clusters of workstations. A further point of emphasis was laid on the development of a parallel decomposition strategy calles PARDEC, for the solution of very complex optimization problems which cannot be solved efficiently by sequential integrated optimization. The use of the OptiX-Workbench together with the FEM ground water simulation system FEFLOWis shown for a special water management problem. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] A finite element-based level set method for structural optimizationINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 7 2010Xianghua Xing Abstract A finite element-based level set method is implemented for structural optimization. The streamline diffusion finite element method is used for solving both the level set equation and the reinitialization equation. The lumped scheme is addressed and the accuracy is compared with the conventional finite difference-based level set method. A Dirichlet boundary condition is enforced during the reinitialization to prevent the boundary from drifting. Numerical examples of minimum mean compliance design illustrate the reliability of the proposed optimization method. Copyright © 2009 John Wiley & Sons, Ltd. [source] An adaptive penalty scheme for genetic algorithms in structural optimizationINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 5 2004Afonso C. C. Lemonge Abstract A parameter-less adaptive penalty scheme for genetic algorithms applied to constrained optimization problems is proposed. Using feedback from the evolutionary process the procedure automatically defines a penalty parameter for each constraint. The user is thus relieved from the burden of having to determine sensitive parameter(s) when dealing with every new constrained optimization problem. The procedure is shown to be effective and robust when applied to test problems from the evolutionary computation literature as well as several optimization problems from the structural engineering literature. Copyright © 2003 John Wiley & Sons, Ltd. [source] An improved weighting method with multibounds formulation and convex programming for multicriteria structural optimizationINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 9 2001W. H. Zhang Abstract This paper presents an improved weighting method for multicriteria structural optimization. By introducing artificial design variables, here called as multibounds formulation (MBF), we demonstrate mathematically that the weighting combination of criteria can be transformed into a simplified problem with a linear objective function. This is a unified formulation for one criterion and multicriteria problems. Due to the uncoupling of involved criteria after the transformation, the extension and the adaptation of monotonic approximation-based convex programming methods such as the convex linearization (CONLIN) or the method of moving asymptotes (MMA) are made possible to solve multicriteria problems as efficiently as for one criterion problems. In this work, a multicriteria optimization tool is developed by integrating the multibounds formulation with the CONLIN optimizer and the ABAQUS finite element analysis system. Some numerical examples are taken into account to show the efficiency of this approach. Copyright © 2001 John Wiley & Sons, Ltd. [source] Coherence of Structural Optimization and Configurational MechanicsPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2006Daniel Materna This contribution is concerned with the similarities of structural optimization and configurational mechanics. In structural optimization sensitivity analysis is used to obtain the sensitivity of continuum mechanical functions with respect to variations of the material body, i.e. the reference configuration. In the same manner in configurational mechanics we are interested in changes of the material body, e.g. crack propagation or phase transition problems. Consequently, variational design sensitivity analysis and the numerical techniques from structural optimization are applicable to problems fromconfigurational mechanics. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Toward the development of new medicinal leads with selectivity for protein kinase C isozymesTHE CHEMICAL RECORD, Issue 4 2005Kazuhiro Irie Abstract Tumor promoters such as phorbol esters bind strongly to protein kinase C (PKC) isozymes to induce their activation. Since each PKC isozyme is involved in diverse biological events in addition to tumor promotion, the isozymes serve as promising therapeutic targets. Tumor promoters bind to the C1A and/or C1B domain of conventional (,, ,I, ,II, and ,) and novel PKC isozymes (,, ,, ,, and ,). As these C1 domains play differential roles in PKC activation and their translocation in cells, the development of agents with binding selectivity for individual C1 domains is a pressing need. For this purpose, we established a synthetic C1 peptide library of all PKC isozymes. The library enabled us to identify indolactam-V (1) as a promising lead compound. Our diverse structure,activity studies on 1 indicated that the position of the hydrophobic substituent on the indole ring dominates the PKC isozyme- and C1 domain-selective binding rather than conformation of the nine-membered lactam. Moreover, we suggested that the indole ring of 1 could be involved in the CH/, interaction with Pro-11 of the C1B domain of PKC,. This invaluable information will lead to the structural optimization of the PKC, ligand as exemplified by the design and synthesis of naphtholactam-V8 (21). © 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 5: 185,195; 2005: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20044 [source] Design, Synthesis, and Antifungal Activity of Novel Conformationally Restricted Triazole DerivativesARCHIV DER PHARMAZIE, Issue 12 2009Wenya Wang Abstract A series of new triazole derivatives were designed and synthesized on the basis of the active site of lanosterol 14,-demethylase from Candida albicans (CACYP51). 2-(2,4-Difluorophenyl)-3-(methyl-(3-phenoxyalkyl)amino)-1-(1H -1,2,4-triazol-1-yl)propan-2-ols show excellent in-vitro activity against most of the tested pathogenic fungi. The MIC80 value of compound 8a against Candida albicans is 0.01 ,M, which provides a good starting template for further structural optimization. The binding modes of the designed compounds were investigated by flexible molecular docking. The compounds interacted with CACYP51 through hydrophobic, van-der-Waals, and hydrogen-bonding interactions. [source] Ab-initio simulations of materials using VASP: Density-functional theory and beyondJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 13 2008Jürgen Hafner Abstract During the past decade, computer simulations based on a quantum-mechanical description of the interactions between electrons and between electrons and atomic nuclei have developed an increasingly important impact on solid-state physics and chemistry and on materials science,promoting not only a deeper understanding, but also the possibility to contribute significantly to materials design for future technologies. This development is based on two important columns: (i) The improved description of electronic many-body effects within density-functional theory (DFT) and the upcoming post-DFT methods. (ii) The implementation of the new functionals and many-body techniques within highly efficient, stable, and versatile computer codes, which allow to exploit the potential of modern computer architectures. In this review, I discuss the implementation of various DFT functionals [local-density approximation (LDA), generalized gradient approximation (GGA), meta-GGA, hybrid functional mixing DFT, and exact (Hartree-Fock) exchange] and post-DFT approaches [DFT + U for strong electronic correlations in narrow bands, many-body perturbation theory (GW) for quasiparticle spectra, dynamical correlation effects via the adiabatic-connection fluctuation-dissipation theorem (AC-FDT)] in the Vienna ab initio simulation package VASP. VASP is a plane-wave all-electron code using the projector-augmented wave method to describe the electron-core interaction. The code uses fast iterative techniques for the diagonalization of the DFT Hamiltonian and allows to perform total-energy calculations and structural optimizations for systems with thousands of atoms and ab initio molecular dynamics simulations for ensembles with a few hundred atoms extending over several tens of ps. Applications in many different areas (structure and phase stability, mechanical and dynamical properties, liquids, glasses and quasicrystals, magnetism and magnetic nanostructures, semiconductors and insulators, surfaces, interfaces and thin films, chemical reactions, and catalysis) are reviewed. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2008 [source] | |||||||||||||