bluuebunny/crossref_metadata_2025_split huggingface dataset:
A strategic assessment of six sigma
Authors: Goh T. N. 
Published: October 2002

AbstractSix Sigma as a quality improvement framework has been gaining considerable attention in recent years. The hyperbole that often accompanied the presentation and adoption of Six Sigma in industry could lead to unrealistic expectations as to what Six Sigma is truly capable of achieving. In this paper, some strategic perspectives on the subject are presented, highlighting the potential and possible limitations of Six Sigma applications particularly in a knowledge‐based environment. Without delving into the mechanics of the subject in detail, the points raised could be useful to those deliberating on the appropriateness of Six Sigma to their respective organizations. Copyright © 2002 John Wiley & Sons, Ltd.
Theoretical study of the hydrogen bond interaction between methylene blue and water and possible role on energy transfer for photodynamics
Authors: Quintão Andréa Dias , Coutinho Kaline , Canuto Sylvio 
Published: October 2002

AbstractDensity‐functional theory calculations using B3LYP/6‐31+G(d) are performed on the hydrogen bond interaction between methylene blue (MB+) and water to analyze the structure, binding energy and change in spectroscopic properties. The vibrational frequency observed in the region of 1200 cm−1is found to present the larger shift (+10 cm−1), and corresponds to the asymmetric in‐plane twist mode of CC bond of the central ring. The binding energy between MB+and water is calculated for three different isomers giving values varying between 3.1 and 5.1 kcal/mol, after correcting for basis‐set superposition error. The binding energy is also calculated using Hartree–Fock and other density‐functionals, such as B3P86/6‐31+G(d) and B3PW91/6‐31+G(d). In the most stable isomer considered, the water plays the role of the proton acceptor and the oxygen atom makes multiple hydrogen bonds with MB+. The stability of this isomer is also influenced by other electrostatic interaction between MB+and water. The influence of the complexation on the characteristic visible absorption band of MB+is analyzed using INDO/CIS. Overall, the results indicate that several hydrogen bonds can be formed and some present multiple bonds. However, they all seem to be numerically unimportant for the photochemistry of MB+in water. © 2001 Wiley Periodicals, Inc. Int J Quantum Chem, 2001
Atomic and molecular energies in terms of electrostatic potentials at nuclei
Authors: Politzer Peter , Lane Pat , Concha Monica C. 
Published: October 2002

AbstractSeveral formulas, both exact and approximate, that relate atomic and molecular energies to electrostatic potentials at nuclei are discussed in terms of the relative contributions of the nuclear–electronic, nuclear–nuclear, and electronic–electronic interactions. These quantities and related ratios are evaluated at the density functional B3PW91/6‐311+G(3df,2pd) level for a group of 24 molecules. A modified version of an approximate molecular energy expression is tested and found to give improved results. © 2002 John Wiley & Sons, Inc. Int J Quantum Chem, 2002
Comparison of different atomic charge schemes for predicting pKavariations in substituted anilines and phenols*
Authors: Gross Kevin C. , Seybold Paul G. , Hadad Christopher M. 
Published: October 2002

AbstractA number of different methods have been proposed for assigning partial charges to the atoms of a molecule, including both quantum chemical and empirical schemes. A reasonable expectation for any successful calculational scheme is that the atomic charges it produces should vary in a manner consistent with chemical intuition and, more specifically, that these variations should be correlated in a sensible way with experimental observations. Seven of the most popular atomic charge schemes (Bader's AIM chargesQAIM, electrostatic potential chargesQESP, GAPT chargesQGAPT, Gasteiger π chargesQGast, Löwdin chargesQLöw, Mulliken chargesQMul, and charges derived from natural population analysisQNPA) were tested for their ability to represent variations in the pKa's of 19 monosubstituted anilines and 19 monosubstituted phenols. In most cases the calculations were performed at the B3LYP/6‐311G** level of theory. For the substituted anilines, the amino nitrogen, anilinium proton, and total amino group charges were taken as representative regression parameters, and for the phenols, the phenolic hydrogen, phenoxide oxygen, and hydroxyl group charges were employed. Overall,QAIM,QLöw, andQNPAyielded the most successful correlations with the pKa's of these compounds, although for the phenol series,QGAPTandQMulalso yielded good results. © 2002 John Wiley & Sons, Inc. Int J Quantum Chem, 2002
Ab initio calculations of the NMR properties of the NH3 … HH2O complex
Authors: Janowski Tomasz , Jaszuński Michał 
Published: October 2002

AbstractThe shielding constants, nuclear quadrupole coupling constants, and spin–spin coupling constants are computed for the ammonia–water complex. Four structures of the complex are considered. A series of multiconfiguration self‐consistent field (MCSCF) wavefunctions is applied for the trans conformer to estimate the role of electron correlation, and a selected MCSCF function is next systematically used for all the other conformers. The largest changes of all the nuclear magnetic resonance (NMR) parameters with respect to the monomers are observed for the nuclei participating in the hydrogen bond, and they are similar for the trans and cis conformers. The parameter changes due to the interaction are significant also for both bifurcated structures of the complex, even though there is no hydrogen bond. The electron correlation effects are not negligible, in particular for the spin–spin coupling constants. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Three‐center nuclear attraction, three‐center two‐electron Coulomb and hybrid integrals over B functions evaluated using the nonlinear S\documentclass{article}\pagestyle{empty}\begin{document}$\overline{D}$\end{document} transformation
Authors: Safouhi Hassan , Hoggan Philip 
Published: October 2002

AbstractThis work describes and applies the nonlinear \documentclass{article}\pagestyle{empty}\begin{document}$S\overline{D}$\end{document} transformation, recently developed by the first author, to accelerate the convergence of semi‐infinite integrals occurring in molecular structure electronic energy calculations. These energy terms must be evaluated precisely and quickly. The approach chosen involves expanding Slater type atomic orbital basis functions over B functions to exploit the compact Fourier transforms of B functions. The resulting integrals have been evaluated in previous work using the nonlinear D (due to Levin and Sidi) and \documentclass{article}\pagestyle{empty}\begin{document}$\overline{D}$\end{document} (due to Sidi) transformations and some improved nonlinear transformations HD and \documentclass{article}\pagestyle{empty}\begin{document}$H\overline{D}$\end{document} have been developed. These methods are precise and faster than alternatives for convergence acceleration of oscillatory integrals involved. In the present work a more recent, highly compact, and convenient nonlinear transformation \documentclass{article}\pagestyle{empty}\begin{document}$S\overline{D}$\end{document} is described and applied to the three‐center nuclear attraction integral common to ab initio and density functional theory work. Three‐center Coulomb and hybrid integrals which occur in ab initio self‐consistent field work are also evaluated. This approach is shown to represent a further substantial advance in efficiency and should lead to a definitive suite of ab initio Slater software. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Atomic spin‐density polarization index and atomic spin‐density information entropy distance
Authors: Fuentealba P. , Melin Junia 
Published: October 2002

AbstractIt is shown that information theory concepts based on the Shanon entropy are useful to define indices yielding a quantitative measure of spin polarization. Numerical results for the ground state of all the atoms from He to Xe are presented. They were obtained by solving numerically the Kohn–Sham equations with two different approximations for the exchange–correlation functionals. The defined indices predict very nicely the periodical trends along the periodical table of elements. They are numerically great for atoms with the greater spin multiplicity and zero for closed‐shell atoms. © 2002 John Wiley & Sons, Inc. Int J Quantum Chem, 2002
A rapid screening method for routine congener‐specific analysis of polychlorinated biphenyls in human serum by high‐resolution gas chromatography with mass spectrometric detection
Authors: Turci Roberta , Angeleri Federica , Minoia Claudio 
Published: October 2002

AbstractA screening method using gas chromatography/mass spectrometry in the single ion monitoring (SIM) mode for the routine congener‐specific analysis of polychlorinated biphenyls (PCBs) in human serum has been developed and validated. A fast procedure incorporating both liquid‐liquid and solid‐phase extraction was used for clean up and enrichment. Interday and intraday precision and accuracy were assessed for the 12 congeners having dioxin‐like activity and PCBs #180 and #170 by analyzing spiked samples on three subsequent days and using 13C12‐labelled analogues as internal standards. Furthermore, the relative errors for six non‐dioxin‐like congeners (PCBs #28, #52, #101, #138, #153 and #180) were measured by using certified reference materials, providing good accuracy at two different concentration levels. The limits of quantification and of detection were 0.5 and 0.2 µg/L in serum for each congener, respectively. The method allows the chromatographic separation of at least 35 congeners and can therefore be applied to the routine monitoring of the general population for both dioxin‐like and non‐dioxin‐like PCB congeners. Copyright © 2002 John Wiley & Sons, Ltd.
Investigation and correction of the gene‐derived sequence of glutenin subunit 1Dx2 by matrix‐assisted laser desorption/ionisation mass spectrometry
Authors: Cunsolo Vincenzo , Foti Salvatore , Saletti Rosaria , Gilbert Simon , Tatham Arthur S. , Shewry Peter R. 
Published: October 2002

AbstractDirect matrix‐assisted laser desorption/ionisation time‐of‐flight mass spectrometry (MALDI‐TOFMS) analysis of a mixture of tryptic peptides was used to verify the gene‐derived amino acid sequence of the high molecular weight (HMW) subunit 1Dx2 of bread wheat. Analysis of the digest was performed by recording several MALDI mass spectra of the mixture at low, medium and high mass ranges, and optimising the matrix and the acquisition parameters for each mass range. This resulted in coverage of the whole sequence except for a short fragment T3 (3 amino acids), which was not detected. It also allowed the insertion of a Pro residue in position 59 to be identified. The results obtained provide evidence for the lack of a substantial level of glycosylation or other post‐translational modifications of subunit 1Dx2, and demonstrate that MALDI‐MS is the most useful method presently available for the direct verification of the gene‐derived sequences of HMW glutenin subunits and similar proteins. Copyright © 2002 John Wiley & Sons, Ltd.
Hydrogen/deuterium exchange of myoglobin ions in a linear quadrupole ion trap
Authors: Mao Dunmin , Ding Chuanfan , Douglas D. J. 
Published: October 2002

AbstractThe hydrogen/deuterium (H/D) exchange of gas‐phase ions of holo‐ and apo‐myoglobin has been studied by confining the ions in a linear quadrupole ion trap with D2O or CD3OD at a pressure of several mTorr. Apo‐myoglobin ions were formed by collision‐induced dissociation of holo‐myoglobin ions between the orifice and skimmer of the ion sampling system. The exchange takes place on a time scale of seconds. Earlier cross section measurements have shown that holo‐myoglobin ions can have more compact structures than apo‐myoglobin. Despite this, both holo‐myoglobin and apo‐myoglobin in charge states +8 to +14 are found to exchange nearly the same number of hydrogens (ca. 103) in 4 s. It is possible the ions fold or unfold to new conformations on the much longer time scale of the exchange experiment compared with the cross section measurements. Copyright © 2002 John Wiley & Sons, Ltd.
Evaluation of white‐rot fungi for the remediation of creosote‐contaminated soil
Authors: Lamar Richard T. , White Richard B. , Ashley Karl C. 
Published: October 2002

AbstractApplication of fungal‐based bioaugmentation was evaluated for the remediation of
creosote‐contaminated soil at a wood‐preserving site in West Virginia. Soil at the site contained
creosote‐range polycyclic aromatic hydrocarbons (PAHs) at concentrations in some areas that
exceed industrial risk‐based levels. Two white‐rot fungi (Pleurotus ostreatus and
Irpex lacteus) were evaluated for remediation effectiveness in a two‐month
bench‐scale treatability test. Both fungi produced similar results, with up to 67.3 percent degradation
of total PAHs in 56 days. Pilot‐scale testing was performed at the site using Pleurotus
ostreatus grown on two local substrate mixtures. During the 276‐day field trial, total PAHs were
degraded by up to 93.2 percent, with all individual PAHs except one achieving industrial risk‐based
concentrations. It was recommended that fungal‐based remediation be applied to all contaminated soil at
the site. © 2002 Wiley Periodicals, Inc.
Formation and characterization of thin films of H(CH2)xPO(OH)2 on polycrystalline zinc substrates
Authors: Sinapi F. , Forget L. , Delhalle J. , Mekhalif Z. 
Published: October 2002

AbstractMonolayers of n‐pentanephosphonic or n‐tetradecanephosponic acids are obtained by immersion of mechanically polished zinc substrates in solutions of either absolute ethanol or a mixture of water/ethanol (25/75%). X‐ray photoelectron spectroscopy, contact angle and scanning Kelvin probe measurements indicate that both compounds lead to good‐quality monolayers and the longer alkyl chain n‐tetradecanephosponic acid molecules form the more densely packed films. However, the best films (n‐tetradecanephosponic acids) do not show any resistance to electrochemical assays (polarization curves in NaOH and NaCl). Copyright © 2002 John Wiley & Sons, Ltd.
Corrosion of brass in ultrapure water
Authors: Zhdan P. A. , Castle J. E. 
Published: October 2002

AbstractCorrosion at the nano‐thickness level is significant in the heat exchangers of power stations because of the subsequent transport of released copper throughout the steam/water circuit. One the most significant factors determining the extent of corrosion is the level of dissolved oxygen. In the work to be described, samples of admiralty brass have been exposed to pure water at 95°C at different oxygen levels: the oxygen level is monitored at very low concentrations by use of the oxidation–reduction potential.All samples were characterized by measurement of the surface roughness using atomic force microscopy as a function of exposure time, and it will be shown that there is an excellent correlation between surface topography and the release of metal ions to solution. Representative samples were analysed using XPS and it is shown that a higher copper release rate is usually associated with the appearance of cupric oxide on the surface. Copyright © 2002 John Wiley & Sons, Ltd.
Fine determination of interatomic distances on surface using extended energy‐loss fine structure (EELFS) data: peculiarities of the technique
Authors: Wainstein D. L. , Kovalev A. I. 
Published: October 2002

AbstractFor determination of interatomic distances on a surface we use spectra below the lines of backscattered electrons and below the Auger lines. In contrast to other authors, who record spectra in dN/dE mode for extended energy‐loss fine structure (EELFS) analysis, the integral N(E) mode is used with further filtering of the structure‐dependent oscillations by original software. The sequence of structure‐dependent oscillation extraction from the energy‐loss spectrum is presented, including the following main stages: synthesis of peak and inelastic background and detection of inelastic oscillations; normalization of the inelastic spectrum; recalculation of the spectrum to K‐space; and Fourier transformation.Good agreement between theoretical and experimentally obtained interatomic distances for various systems (multicomponent grain boundary segregations in steels, hard diamond‐like coatings and films generated on the surface of cutting tools with engineered coatings) is observed. Detailed results of application of EELFS for investigation of the atomic structure of these systems are presented.In particular, the results of EELFS analysis of hard amorphous hydrogenated carbon films show the ability of this method to resolve interatomic bonds of different types (sp, sp2, sp3, aromatic bonds). The ‘carbon–hydrogen’ distances are also determined. Copyright © 2002 John Wiley & Sons, Ltd.
Surface composition changes in GaN induced by argon ion bombardment
Authors: Kovač J. , Zalar A. 
Published: October 2002

AbstractThe wide‐bandgap GaN semiconductor has been used to fabricate efficient blue–green light‐emitting diodes, laser diodes and high‐power/high‐temperature electronic devices since the many problems regarding the life‐time characteristics were resolved in recent years. Knowledge of ion‐bombardment‐induced surface composition changes is important in quantitative AES/XPS analysis.We investigated the dependence of preferential sputtering of components on ion energies and on the angle of incidence of argon ions. Thin films of GaN prepared on a smooth Si substrate and GaN single crystals were bombarded with argon ions of energy 0.5–5 keV at incidence angles of 10–72° with respect to the surface normal. The N KLL and Ga LMM AES signals were acquired after the steady‐state surface composition was reached. The results show that nitrogen is sputtered preferentially. This effect is more pronounced for higher ion energies and smaller incidence angles. The experimental results are discussed in the framework of models of preferential sputtering and compared with computer simulations. Copyright © 2002 John Wiley & Sons, Ltd.
Auger parameter studies of aluminium–transition metal alloys
Authors: Abel Marie‐Laure , Tsakiropoulos Panos , Watts John F. , Matthew James A. D. 
Published: October 2002

AbstractWithin a general study of transition metal (TM) alloys, the variation of the Auger parameters of Fe–10 at.% Al and Fe–50 at.% Al relative to the pure metal was determined. Initial‐ and final‐state Auger parameters were calculated and related to charge transfer calculations. Iron exhibits almost pure metal behaviour, particularly in Fe10Al, but Al core holes are more poorly screened than in Al metal. Charge transfer inferred from the final‐state Auger parameters suggests that Al carries a positive charge consistent with the electronegativity differences of Fe and Al. However, there is no evidence of Fe carrying a corresponding negative charge: furthermore, positive Al charge is inconsistent with the Al initial‐state parameter. This suggests, rather, that the Alsp–Fesd bonds in the alloys are less polarizable than Al bonds in the nearly free electron metal, a concept supported by the reduction in Al 2p plasmon satellite intensity on alloying and the increased plasmon energy associated with the enhanced valence electron density. Copyright © 2002 John Wiley & Sons, Ltd.
Role of sulphur in carburization, carbide formation and metal dusting of iron
Authors: Grabke H. J. , Moszynski D. , Müller‐Lorenz E. M. , Schneider A. 
Published: October 2002

AbstractThe kinetics and mechanisms of reactions on iron in CH4–H2 and CO–H2–H2O mixtures have been studied, also in the presence of H2S, to understand carburization, iron carbide formation, metal dusting and carbon deposition. Rate equations and mechanisms of the carburization in CH4–H2 and CO–H2–H2O have been elucidated. Both reactions are retarded by adsorbed sulphur, the rates becoming inversely proportional to the sulphur activity aS ∼ p(H2S)/p(H2) with increasing aS. At carbon activities aC > 1, cementite growth can be started in both gas mixtures on iron but the decomposition of this unstable carbide gives rise to a corrosion process called ‘metal dusting’, i.e. a disintegration of iron and steels to a dust of metal particles and graphitic carbon. This disintegration can be prevented by adsorbed sulphur, which hinders the nucleation of graphite. The stabilizing effect of sulphur on cementite and higher carbides such as Hägg carbide allows fundamental studies to be carried out on their thermodynamics, non‐stoichiometry and diffusional growth mechanisms, and the presence of sulphur will allow iron carbide production in a process of great present interest—the direct reduction of iron ores in carburizing gas mixtures. Kinetic studies in the system Fe–C–S are supplemented by AES and low‐energy electron diffraction investigations on the adsorption and segregation of sulphur on iron and cementite. Copyright © 2002 John Wiley & Sons, Ltd.
Formation of petroleum organic deposits on steel surfaces
Authors: Cosultchi A. , García‐Bórquez A. , Aguilar‐Hernandez J. , Yee‐Madeira H. , Reguera E. , Lara V. H. , Bosch P. 
Published: October 2002

AbstractAn adhered organic deposit, formed within the petroleum well on the steel surface of the tubing walls, was systematically characterized following a sequence of bulk and surface techniques. The results allowed the identification of the tubing wall and its internal surface structures. As a consequence of the contact with sulphur‐bearing compounds such as H2S and brine from petroleum, the pre‐oxidized steel surface was modified by non‐stoichiometric iron compound formation. These new iron phases favour adsorption and chemisorption of the petroleum polar compounds on the steel surface. Copyright © 2002 John Wiley & Sons, Ltd.
Application of argon r.f. plasma etching for the removal of oxidic scales on ULC steels
Authors: Martínez C. , Kyrsta S. , Cremer R. , Neuschütz D. 
Published: October 2002

AbstractThe effects of argon r.f. plasma etching processes on steel samples at discharge voltages substantially lower than 300 V were studied. The removal of not only the hydrocarbon contamination of the surface but also of the native oxidic scale was investigated by means of x‐ray photoelectron spectroscopy (XPS). Special attention was paid to the remaining structure of the surface after etching, using reflection high‐energy electron diffraction (RHEED) to determine the influence of plasma etching on the crystallographic structure. The removal of hydrocarbons was already effective at a power of 20 W. At a power of 60 W it was possible to remove the native oxidic scale in only a few minutes. In contrast to the amorphization observed after etching at high Ar+ energies, the crystalline structure of the outermost layers was not significantly influenced by the low‐energy ion etching. Copyright © 2002 John Wiley & Sons, Ltd.
Oxidation of the silicon carbide surface in Watts' plating bath
Authors: Socha R. P. , Laajalehto K. , Nowak P. 
Published: October 2002

AbstractAn important problem in metal–matrix composite production by electrochemical co‐deposition of SiC particles with nickel is the large variation of the SiC concentration in the composite. One of the possible reasons is the change of SiC surface properties due to its oxidation during contact with the plating bath. X‐ray photoelectron spectroscopy was applied to study the surface oxidation of the [0001] basal plane of α‐SiC crystals contacted with Watts' plating bath at 55°C. It was shown that the growth of silica at the surface is preceded by the formation of a silicon oxycarbide species (SiOxCy). The formation of graphite‐type carbon at the surface was also observed. The equivalent layer thickness of the main species at the oxidized surface was calculated. Copyright © 2002 John Wiley & Sons, Ltd.