bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solution to shape identification problem of unsteady heat‐conduction fields
Authors: Katamine Eiji , Azegami Hideyuki , Matsuura Yasuhiro 
Published: April 2003

AbstractThis paper presents a numerical analysis method for shape determination problems of unsteady heat‐conduction fields in which time histories of temperature distributions on prescribed subboundaries or time histories of gradient distributions of temperature in prescribed subdomains have prescribed distributions. The square error integrals between the actual distributions and the prescribed distributions on the prescribed subboundaries or in the prescribed subdomains during the specified period of time are used as objective functionals. Reshaping is accomplished by the traction method that was proposed as a solution to shape optimization problems of domains in which boundary value problems are defined. The shape gradient functions of these shape determination problems are derived theoretically using the Lagrange multiplier method and the formulation of material derivative. The time histories of temperature distributions are evaluated using the finite‐element method for a space integral and the Crank–Nicolson method for a time integral. Numerical analyses of nozzle and coolant flow passage in a wing are demonstrated to confirm the validity of this method. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(3): 212–226, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10086
Numerical analysis of microwave heating of a dielectric
Authors: Funawatashi Yuichi , Suzuki Tateyuki 
Published: April 2003

AbstractMicrowave heating of a dielectric in a cavity was analyzed numerically with the FDTD method with the aim of devising new methods for reducing uneven heating typical of microwaving. The dielectric was assumed to be water and the frequency of a microwave was taken to be 1 GHz. It was found that the electric field is highly dependent on the position of the dielectric in a cavity. The temperature distribution reflects the profile of the RMS value of the electric field in the dielectric, although there appears to be no effect of the short wavelength typical of the electric field. The heating rate depends on the position of the dielectric. In the case of a higher effective loss factor a microwave decays immediately after entering the dielectric, and the temperature of the interior remains low. These results indicate that the uneven heating is due to at least two causes: standing wave and rapid decay of a microwave. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(3): 227–236, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10087
Evaluation tests of 1700 °C class turbine cooled blades for a hydrogen fueled combustion turbine system
Authors: Okamura Takanari , Kawagishi Hiroyuki , Koga Akinori , Itoh Shoko 
Published: April 2003

AbstractThe development of 1700 °C class hydrogen fueled combustion turbine system with output of 500 MW and thermal efficiency of over 60% (HHV) has been conducted in the World Energy Network (WE‐NET) program. This paper describes the development of the first‐stage turbine cooled stator and rotor blades applied to the power generation system. The conceptual design of these cooling blades which were served in hot steam flow was carried out. The hybrid cooling method combining recovery cooling with partial ejection cooling was chosen from several cooling systems from a viewpoint of plant efficiency, operational reliability, and durability of cooled blades. Also, the single crystal superalloy (SC) as a blade substrate and thermal barrier coating (TBC) were applied. The experiments of the scale model turbine cooled blades were carried out using a hydrogen–oxygen combustion wind tunnel with practical steam conditions of 1700 °C and 2.5 MPa. The cooling effectiveness and metal temperature at rated condition and the soundness of TBC and blade substrate of the first stage stator and rotor test blades were clarified. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(3): 237–252, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10088
Influence of inclination angle, attack angle, and arrangement of rectangular vortex generators on heat transfer performance
Authors: Tanaka Takeo , Itoh Masaaki , Hatada Toshio , Matsushima Hitoshi 
Published: April 2003

AbstractWe have studied the enhancement of heat transfer by vortex generators. Experiments were performed on rectangular‐type vortex generators mounted on a parallel‐plate heater, and the heat transfer coefficient of the heater surface and pressure drop in the duct were measured. These measurements indicated that a rectangular vortex generator (called a double‐inclined winglet), with inclination angle of the vortex generator surface to the heater surface (β) at 60°, and the attack angle to the flow direction (γ) at 45°, maximizes the local Nusselt number of the heater surface. It was also found that a group of double‐inclined winglets has an optimal arrangement in a winglet array, longitudinal pitch and transverse pitch, that maximizes the ratio [Colburn's dimensionless heat transfer coefficient JH]/[friction factor f]. The results of numerical calculations showed that the double‐inclined winglet was superior to the conventional rectangular vortex generator in heat transfer. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(3): 253–267, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10089
Thermal contact resistance between an element and a housing in an aluminum electrolytic capacitor
Authors: Suzuki Osamu , Sasaki Kaname , Kuwahara Heikichi 
Published: April 2003

AbstractCooling performance of an aluminum electrolytic capacitor, whose element pressed on the inner bottom surface of the capacitor housing in order to decrease thermal contact resistance between the element and the housing, was measured and improved. It was found that a thermally conductive elastomer decreases this contact resistance. The elastomer with a thickness ranging from 0.5 to 1.5 mm was inserted between the bottom surface of the capacitor element and the plain metal surface. Experimental measurements show that the contact resistance with the 0.5‐mm‐thick elastomer is smaller than that without an elastomer. A simple analysis was also developed for predicting the thermal contact resistance with different elastomer thicknesses, and these predicted resistances agree reasonably well with the experimental measurements. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(3): 268–277, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10090
Fluid flow and heat transfer of natural convection adjacent to upward‐facing inclined heated plates
Authors: Kimura Fumiyoshi , Kitamura Kenzo , Yamaguchi Manabu , Asami Toshihiko 
Published: April 2003

AbstractTurbulent transition mechanism and local heat transfer characteristics of the natural convective flows over upward‐facing inclined plates were investigated experimentally. The experiments were performed in the range of modified local Rayleigh numbers from 104 to 8 × 1014 and of inclination angles θ from 0 to 90°. The flow fields over the plate and the surface temperatures of the plate were visualized with dye and liquid crystal thermometry. The results showed that longitudinal vortices play a main role in the turbulent transition over the plate of θ < 72°. These vortices appear first in the laminar boundary layer, then detach from the plate and, finally become distorted. It is found that the heat transfer is enhanced markedly by the detachment and the distortion of these vortices. The local heat transfer coefficients were measured in the laminar, transitional, and turbulent regions. The results show that the coefficients in the turbulent region become identical and independent of inclination angles. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(3): 278–291, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10091
Selective descriptor pruning for QSAR/QSPR studies using artificial neural networks
Authors: Turner Joseph V. , Cutler David J. , Spence Ian , Maddalena Desmond J. 
Published: April 2003

AbstractSelection of optimal descriptors in quantitative structure–activity–property relationship (QSAR/QSPR) studies has been a perennial problem. Artificial Neural Networks (ANNs) have been used widely in QSAR/QSPR studies but less widely in descriptor selection. The current study used ANNs to select an optimal set of descriptors using large numbers of input variables. The effects of clean, noisy, and random input descriptors with linear, nonlinear, and periodic data on synthetic and real data QSAR/QSPR sets were examined. The optimal set of descriptors could be determined using a signal‐to‐noise ratio method. The optimal values for the rho parameter, which relates sample size to network architecture, were found to vary with the type of data. ANNs were able to detect meaningful descriptors in the presence of large numbers of random false descriptors. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 891–897, 2003
Predicting structural models for silicon clusters
Authors: Zacharias Carlos Renato , Lemes Maurício Ruv , Dal Pino Arnaldo , Santo Orcero David 
Published: April 2003

AbstractThis article introduces an efficient method to generate structural models for medium‐sized silicon clusters. Geometrical information obtained from previous investigations of small clusters is initially sorted and then introduced into our predictor algorithm in order to generate structural models for large clusters. The method predicts geometries whose binding energies are close (95%) to the corresponding value for the ground‐state with very low computational cost. These predictions can be used as a very good initial guess for any global optimization algorithm. As a test case, information from clusters up to 14 atoms was used to predict good models for silicon clusters up to 20 atoms. We believe that the new algorithm may enhance the performance of most optimization methods whenever some previous information is available. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 869–875, 2003
Theoretical study of the interaction between a high‐valent manganese porphyrin oxyl‐(hydroxo)‐Mn(IV)‐TMPyP and double‐stranded DNA
Authors: Arnaud Philippe , Zakrzewska Krystyna , Meunier Bernard 
Published: April 2003

AbstractCationic porphyrin derivatives such as meso‐tetrakis(4‐N‐methylpyridinium)porphyrin, TMPyP, have been shown to interact with double‐stranded DNA. The manganese derivative, Mn(III)‐TMPyP, activated by an oxygen donor like potassium monopersulfate, provides an efficient DNA‐cleaving system. Previous experimental work1 has shown that DNA cleavage by the Mn(III)‐TMPyP/KHSO5 system was due to an oxidative attack, within the minor groove of B‐DNA, at the C5′ or C1′ carbons of deoxyribose units. The aim of this study was to use molecular modeling to elucidate the specificity of the interactions between the transient active species oxyl‐Mn(IV)‐TMPyP and the DNA target. Geometric parameters, charges, and force field constants consistent with the AMBER 98 force field were calculated by DFT methods. Molecular modeling (mechanics and dynamic simulations) were performed for oxyl‐(hydroxo)‐Mn(IV)‐TMPyP bound in the minor groove of the dodecamer d(5′‐TCGTCAAACCGC)‐d(5′‐GCGGTTTGACGA). Geometry, interactions, and binding energy of the metalloporphyrin located at the A.T triplet region of the dodecamer were analyzed. These studies show no significant structural change of the DNA structure upon ligand binding. Mobility of the metalloporphyrin in the minor groove was restrained by the formation of a hydrogen bond between the hydroxo ligand trans to the metal‐oxyl and a DNA phosphate, restricting the access of the oxyl group to the (pro‐S) H atom at C5′. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 797–805, 2003
Packing optimization for automated generation of complex system's initial configurations for molecular dynamics and docking
Authors: Martínez José Mario , Martínez Leandro 
Published: April 2003

AbstractMolecular Dynamics is a powerful methodology for the comprehension at molecular level of many chemical and biochemical systems. The theories and techniques developed for structural and thermodynamic analyses are well established, and many software packages are available. However, designing starting configurations for dynamics can be cumbersome. Easily generated regular lattices can be used when simple liquids or mixtures are studied. However, for complex mixtures, polymer solutions or solid adsorbed liquids (for example) this approach is inefficient, and it turns out to be very hard to obtain an adequate coordinate file. In this article, the problem of obtaining an adequate initial configuration is treated as a “packing” problem and solved by an optimization procedure. The initial configuration is chosen in such a way that the minimum distance between atoms of different molecules is greater than a fixed tolerance. The optimization uses a well‐known algorithm for box‐constrained minimization. Applications are given for biomolecule solvation, many‐component mixtures, and interfaces. This approach can reduce the work of designing starting configurations from days or weeks to few minutes or hours, in an automated fashion. Packing optimization is also shown to be a powerful methodology for space search in docking of small ligands to proteins. This is demonstrated by docking of the thyroid hormone to its nuclear receptor. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 819–825, 2003
Structures and energies of D‐galactose and galabiose conformers as calculated by ab initio and semiempirical methods
Authors: Rahal‐Sekkal Majda , Sekkal Nezha , Kleb Dirk C. , Bleckmann Paul 
Published: April 2003

AbstractOptimized geometries and total energies of some conformers of α‐ and β‐D‐galactose have been calculated using the RHF/6‐31G* ab initio method. Vibrational frequencies were computed at the 6‐31G* level for the conformers that favor internal hydrogen bonding, in order to evaluate their enthalpies, entropies, Gibbs free energies, and then their structural stabilities. The semiempirical AM1, PM3, MNDO methods have also been performed on the conformers GG, GT, and TG of α‐ and β‐D‐galactose. In order to test the reliability of each semiempirical method, the obtained structures and energies from the AM1, PM3, and MNDO methods have been compared to those achieved using the RHF/6‐31G* ab initio method. The MNDO method has not been investigated further, because of the large deviation in the structural parameters compared with those obtained by the ab initio method for the galactose. The semiempirical method that has yielded the best results is AM1, and it has been chosen to perform structural and energy calculations on the galabiose molecule (the disaccharides constituted by two galactose units α 1,4 linked). The goal of such calculations is to draw the energy surface maps for this disaccharide. To realize each map, 144 different possible conformations resulting from the rotations of the two torsional angles ψ and ϕ of the glycosidic linkage are considered. In each calculation, at each increment of ψ and ϕ, using a step of 30° from 0 to 330°, the energy optimization is employed. In this article, we report also calculations concerning the galabiose molecule using different ab initio levels such as RHF/6‐31G*, RHF/6‐31G**, and B3Lyp/6‐31G*. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 806–818, 2003
Polarized basis sets of Slater‐type orbitals: H to Ne atoms
Authors: Ema I. , García de la Vega J. M. , Ramírez G. , López R. , Fernández Rico J. , Meissner H. , Paldus J. 
Published: April 2003

AbstractWe present three Slater‐type atomic orbital (STO) valence basis (VB) sets for the first and second row atoms, referred to as the VB1, VB2, and VB3 bases. The smallest VB1 basis has the following structure: [3, 1] for the H and He atoms, [5, 1] for Li and Be, and [5, 3, 1] for the B to Ne series. For the VB2 and VB3 bases, both the number of shells and the number of functions per shell are successively increased by one with respect to VB1. With the exception of the H and Li atoms, the exponents for the VB1 bases were obtained by minimizing the sum of the Hartree–Fock (HF) and frozen‐core singles and doubles configuration interaction (CISD FC) energies of the respective atoms in their ground state. For H and Li, we minimized the sum of the HF and CISD FC energies of the corresponding diatoms (i.e., of H2 or Li2) plus the ground‐state energy of the atom. In the case of the VB2 basis sets, the sum that was minimized also included the energies of the positive and negative ions, and for the VB3 bases, the energies of a few lowest lying excited states of the atom. To account for the core correlations, the VBx (x = 1, 2, and 3) basis sets for the Li to Ne series were enlarged by one function per shell. The exponents of these extended (core‐valence, CV) basis sets, referred to, respectively, as the CVBx (x = 1, 2, and 3) bases, were optimized by relying on the same criteria as in the case of the VBx (x = 1, 2, and 3) bases, except that the full CISD rather than CISD FC energies were employed. We show that these polarized STO basis sets provide good HF and CI energies for the ground and excited states of the atoms considered, as well as for the corresponding ions. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 859–868, 2003
Comparative studies of quasi‐relativistic density functional methods for the description of lanthanide and actinide complexes
Authors: Vetere Valentina , Maldivi Pascale , Adamo Carlo 
Published: April 2003

AbstractWe present a comparative Density Functional Theory (DFT) study based on two different implementations of relativistic effects within the Kohn–Sham (KS) approach, to describe the metal–ligand interaction in I3M‐L complexes (L = NH3, NCCH3, CO and M = La, Nd, U). In the first model, the scalar corrections were included by a quasi‐relativistic approach (QR) via the so‐called ZORA or Pauli Hamiltonians, while in the second, these effects are taken into account in a quasi‐Relativistic Effective Core Potential (RECP). These relativistic approaches were used in conjunction with various gradient corrected (GGA) or hybrid (SCH) functionals. The structural parameters obtained from geometry optimizations have been compared to experimental structural trends, and rationalized by a KS orbital analysis. Both approaches provide similar results for mainly ionic metal–ligand bonds (e.g., for the σ‐donor ligand L = NH3). For the π‐acceptor ligands (NCCH3, CO), the QR approach is in agreement with experimental trends and consistent with the presence of a backbonding interaction between U(III) and the neutral ligand, which does not exist in the lanthanide homologues. The GGA/RECP methods also reproduce this phenomenon, while the SCH/RECP scheme fails to describe this interaction. The role of the RECP, of its size, and of additional polarization functions has also been examined. Finally, the failure of the SCH/RECP approach was interpreted as a consequence of a bad estimation of frontier orbital energy levels in the uranium and ligand species. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 850–858, 2003
Novel topological index for research on structure‐property relationships of complex organic compounds
Authors: Jiang Yu‐Ren , Liu Jing‐Ya , Hu Yue‐Hua , Fujita Toyohisa 
Published: April 2003

AbstractBased on bonding parameters such as Yang's Electronegative Force Gauge Yi, electronic number of valence layer Zi, number of combined hydrogen atoms hi, number of bonding electron bi, and quantum number such as the highest main quantum number of valence layer ni, a novel atomic valence δ is defined and a novel topological index 1χY is derived from the atomic valence. The atomic valence is defined as δ = (Zi − hi)bi/nYi, while the topological index is expressed as 1χY ∑ (δδ)−1/2. Subsequently, the index 1χY is utilized to study the structure‐property relationships of complex organic compounds. The results of correlativity showed that the index is highly and extensively correlated with such properties as solubility of phenyl chlorides, gas chromatographic retention index of alkoxyl silanes, and toxicity of heterocyclic nitrogen‐containing compounds. Moreover, predicted values are quite consistent with experimental ones when the index is employed to predict the partition coefficient (log P) of fatty alcohols, phenyl chlorides, and barbitals. Compared to the topological indices reported in the literature, the universality and reliability of 1χY to the properties of complex organic compounds have been distinctively improved, and its calculating process is simple and convenient. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 842–849, 2003
Inverse Monte Carlo procedure for conformation determination of macromolecules
Authors: Bathe Mark , Rutledge Gregory C. 
Published: April 2003

AbstractA novel numerical method for determining the conformational structure of macromolecules is applied to idealized biomacromolecules in solution. The method computes effective inter‐residue interaction potentials solely from the corresponding radial distribution functions, such as would be obtained from experimental data. The interaction potentials generate conformational ensembles that reproduce thermodynamic properties of the macromolecule (mean energy and heat capacity) in addition to the target radial distribution functions. As an evaluation of its utility in structure determination, we apply the method to a homopolymer and a heteropolymer model of a three‐helix bundle protein [Zhou, Y.; Karplus, M. Proc Natl Acad Sci USA 1997, 94, 14429; Zhou, Y. et al. J Chem Phys 1997, 107, 10691] at various thermodynamic state points, including the ordered globule, disordered globule, and random coil states. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 876–890, 2003
Algorithm for normal mode analysis with general internal coordinates
Authors: Kamiya Kenshu , Sugawara Yoko , Umeyama Hideaki 
Published: April 2003

AbstractA technique for performing normal vibrational analysis for biological macromolecules using general internal coordinates is proposed. The technique is based on the conventional algorithm for calculating the second derivatives of potential and kinetic energies using intramolecular dihedral angles, intermolecular translation, and rotation as variables [Braun, W. et al., J Phys Soc Jpn 1984, 53, 3269]. We extend the algorithm to include more general internal coordinates, bond stretching, angle bending, and so forth, without assuming two‐body interactions. The essential point is the separation of the variables for potential functions and vibrational analysis. With our technique, we can arbitrarily choose any combination of internal coordinates as variables, free from the functional form of potential energy. We can analyze complex systems such as a multiple molecular system including solvents or a transition state of chemical reactions. In addition, mixed use of the potentials of molecular mechanics and quantum chemistry is possible. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 826–841, 2003