bluuebunny/crossref_metadata_2025_split huggingface dataset:
A stabilized 9‐node non‐linear shell element
Authors: Kebari H. , Cassell A. C. 
Published: November 2005

AbstractA non‐linear 9‐node stress resultant shell finite element with six degrees of freedom per node is formulated. The material non‐linearity is based on an implicit integration scheme using the von Mises yield criterion and linear isotropic bardening. The small strain geometric non‐linearity is formulated using the polar decomposition theorem of continuum mechanics via a corotational updated Lagrangian method, which represents finite rotations with accuracy. Reduced integration is used to remove locking and calculate the stresses at their optimal stress accuracy points. A practical procedure is employed to stabilize the troublesome spurious zero energy modes. A number of tests covering the non‐linear material and geometry ranges and buckling show the good performance of the new element.
Genuinely resultant shell finite elements accounting for geometric and material non‐linearity
Authors: Chróścielewski J. , Makowski J. , Stumpf H. 
Published: November 2005

AbstractA general theoretical framework is presented for the fully non‐linear analysis of shells by the finite element method. The governing equations are derived exclusively in terms of resulting quantities through a logical and straightforward descent from three‐dimensional continuum mechanics without appealing to simplifying assumptions (hence the name genuinely resultant). As a result, the underlying theory is statically and geometrically exact, and it naturally includes small strain and finite strain problems of thin as well as thick shells. The underlying mathematical structure and the variational formulation of the theory are examined. This appears to be crucial for the development of computational procedures employing the Newton‐Kantorovich linearization process and the Galerkin type discretization method. The treatment of finite rotations through an arbitrary parametrization of the rotation group and the interpolation procedure of SO(3)‐valued functions underlying the construction of finite element basis are other issues studied in this paper. A numerical analysis is presented in order to assess the effectiveness of the proposed formulation. Small strain problems as well as finite strain deformation of rubber‐like shells undergoing finite rotations are considered. Special attention is devoted to the assessment of the relevance of the drilling degree‐of‐freedom and highly non‐uniform through‐the‐thickness deformation in the case of shells made of incompressible material.
Design and Optimization of airfoils in non‐stalling incompressible flow with a prescribed range of the angle of attack
Authors: Elizarov A. M. , Fokin D. A. 
Published: November 2005

AbstractA simple and reliable method of aerodynamic design of airfoils is proposed for a given range of the angle of attack. The method is based on the solution of a new inverse boundary‐value problem of aerohydrodynamics. In the problem the initial velocity distributions are given along the contour of the required airfoil as a function of the are co‐ordinate for extreme values of the angle of attack from a fixed range. We justify a method of choice of these distributions which guarantees a non‐stalling flow around the airfoil. The problem of airfoil optimization is also considered. Results of numerical calculations are presented.
Diffusion problems using transient discrete source superposition
Authors: Walker S. P. 
Published: November 2005

AbstractDiscrete source superposition techniques seek sets of discrete, singular source strengths which satisfy the boundary conditions of a particular problem, and, necessarily, the governing differential equation. The sum of the fields produced by such sources thus provides an approximation to the required solution. In many respects these techniques are a special case of conventional boundary integral equation methods, where density distributions of smeared sources are sought. In this paper an attempt is made to extend the discrete source superposition technique to transient problems. The example addressed is the transient diffusion equation. The method developed does seem to have sòme promise. It is found that even coarse spatial discretization can yield quite accurate results, and that surprisingly large timesteps can be employed and accuracy maintained. Further, although no direct comparisons are made, the absence of spatial integrations indicates that the computational effort per timestep is likely to be less than for conventional BIE.
Noncovalent synthesis of supramolecular dendritic architectures in water
Authors: Broeren Maarten A. C. , Linhardt Jeffrey G. , Malda Hinke , de Waal Bas F. M. , Versteegen Ron M. , Meijer Joris T. , Löwik Dennis W. P. M. , van Hest Jan C. M. , van Genderen Marcel H. P. , Meijer E. W. 
Published: November 2005

AbstractWater‐soluble guest–host complexes are prepared in a two‐step process. For this a new, polydisperse ethylene glycol containing guest molecule is synthesized that is soluble in both chloroform and water. This guest is able to bind to urea–adamantyl‐modified poly(propylene imine) dendrimers in chloroform in a noncovalent manner. When the chloroform is slowly evaporated and D2O is added, the hydrophobic dendrimer is solubilized in water. This is not possible when the hydrophobic dendrimer is directly added to the hydrophilic guests in water. When the unmodified poly(ethylene glycol) starting material is used, no solubilization occurs, and this indicates that the urea–acetic acid head group is necessary to solubilize the dendrimer. Approximately 26 guests are required for solubilization of the dendrimer. A lower number of guests results in aggregation and precipitation of the dendrimer. A monodisperse guest molecule has been used in NMR studies to show that the guest molecule binds with its acidic head group to the periphery of the dendrimer. This methodology opens the way to functional dendrimer aggregates in aqueous media. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6431–6437, 2005
Synthesis, polymerization, and effects on the flame retardancy of boron‐containing styrenic monomers
Authors: Martín C. , Hunt B. J. , Ebdon J. R. , Ronda J. C. , Cádiz V. 
Published: November 2005

AbstractA boron‐containing styrenic monomer, 5‐benzyl‐2‐phenyl‐5‐(4‐vinylbenzyl)‐[1,3,2]‐dioxaborinane, was synthesized to study the influence of boron on the properties of the homopolymer and copolymer with styrene. A similar monomer without boron was also prepared and polymerized so that the properties of its polymer could be compared with the aforementioned boron‐containing polymers. These monomers were characterized by elemental analysis, mass spectrometry, Fourier transform infrared, and 1H and 13C NMR. The thermal degradation of boron‐containing styrenic polymers was studied by means of Fourier transform infrared, which showed the presence of boric acid as char. The flame‐retardant effect was assessed by the measurement of the limiting oxygen indices and char yields during heating in nitrogen and air. The boron‐containing polymers had higher limiting oxygen indices and gave greater yields of char than those without boron. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem43: 6419–6430, 2005
Reactions of Me2Si(2‐Me‐4,5‐BenzInd)Zr(Cl)(NEt2) and Me2Si(2‐Me‐4,5‐BenzInd)ZrCl2 (BenzInd = benzindenyl) with trimethylaluminum and methylaluminumoxane: Correlation of spectroscopy and propene polymerizations
Authors: Seraidaris Tanja , Löfgren Barbro , Helaja Tuulamari , Vanne Tiina , Mäkelä‐Vaarne Nora 
Published: November 2005

AbstractThe activity of metallocene/methylaluminumoxane (MAO) catalysts in olefin polymerization is highly dependent on both the alkylation and activation of the complexes. The leaving ligands have an important role in the complex activation, influencing the activity of the system. The aim of this work was to study the reactions of complexes Me2Si(2‐Me‐4,5‐BenzInd)2ZrCl2 (A; BenzInd = benzindenyl) and Me2Si(2‐Me‐4,5‐BenzInd)2Zr(Cl)(NEt2) (B) with trimethylaluminum (TMA) and MAO. The reaction kinetics and products were studied by both ultraviolet–visible and NMR spectroscopy. In addition, the polymerization behavior of the different species was investigated in propene polymerizations. Complex B was more easily monomethylated by TMA than complex A and resulted in L2Zr(Me)(NR2)‐type species. Monomethylation of the complexes before polymerization enhanced the polymerization activity of both complexes. When complexes A and B reacted with MAO, similar cationic species were formed, giving equal polymerization activities. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6455–6464, 2005
Polymerization of n‐hexyl isocyanate with CpTiCl2(OR) (R = functional group or macromolecular chain): A route to ω‐functionalized and block copolymers and terpolymers of n‐hexyl isocyanate
Authors: Mourmouris Stylianos , Kostakis Konstantinos , Pitsikalis Marinos , Hadjichristidis Nikos 
Published: November 2005

AbstractWell‐defined ω‐cholesteryl poly(n‐hexyl isocyanate) (PHIC–Chol), as well as diblock copolymers of n‐hexyl isocyanate (HIC) with styrene, PS‐b‐PHIC [PS = polystyrene; PHIC = poly(n‐hexyl isocyanate)], and triblock terpolymers with styrene and isoprene, PS‐b‐PI‐b‐PHIC and PI‐b‐PS‐b‐PHIC (PI = polyisoprene), were synthesized with CpTiCl2(OR) (R = cholesteryl group, PS, or PS‐b‐PI) complexes. The synthetic strategy involved the reaction of the precursor complex CpTiCl3 with cholesterol or the suitable ω‐hydroxy homopolymer or block copolymer, followed by the polymerization of HIC. The ω‐hydroxy polymers were prepared by the anionic polymerization of the corresponding monomers and the reaction of the living chains with ethylene oxide. The reaction sequence was monitored by size exclusion chromatography, and the final products were characterized by size exclusion chromatography (light scattering and refractive‐index detectors), nuclear magnetic resonance spectroscopy, and, in the case of PHIC–Chol, differential scanning calorimetry. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6503–6514, 2005
Relation between thermal conductivity and molecular alignment direction of free‐standing film aligned with rubbing method
Authors: Kato Takashi , Nagahara Takatoshi , Agari Yasuyuki , Ochi Mitsukazu 
Published: November 2005

AbstractThe liquid crystal acryl compounds, in which the molecular directions were aligned by the rubbing method, were polymerized by UV irradiation, to provide the free‐standing aligned films of 200‐μm thickness. The relation between the thermal conductivity and the aligned molecular direction of the films was investigated. The homogeneous film showed the largest magnitude of the thermal conductivity at the direction along the molecular long axis (0.69 W/m K). This was 3.6 times greater than that of poly(methyl methacrylate). The thermal conductivity was dependent on the rotation angle and the concentration of the homogeneous molecular long axis fractions in the networks. These relations were investigated with the twisted film. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3591–3599, 2005
Compatibilization level effects on the structure and mechanical properties of rubber‐modified polyamide‐6/clay nanocomposites
Authors: González I. , Eguiazábal J. I. , Nazábal J. 
Published: November 2005

AbstractExfoliated polyamide‐6 (PA6)/organically modified montmorillonite clay (OMMT) nanocomposites (PNs) were modified with partially maleinized styrene–ethylene/butadiene–styrene triblock copolymers (SEBS) at three maleinization levels in an attempt to link in these materials high toughness with appropriate small‐strain and fracture tensile properties. OMMT stayed only in the PA6 matrix, and no preferential location in the matrix/rubber interphase was observed. The increased dispersed phase size upon the addition of OMMT was attributed to interactions between maleic anhydride (MA) functionalized SEBS and the surfactant of OMMT. The rubber particle size generally decreased when the MA content of SEBS increased, and this indicated compatibilization. The subsequent good adhesion led to tough nanocomposites across a wide range of both strain rates and fracture modes. As the critical interparticle distance (τc) decreased with the MA content, and the other parameters that could influence the surface‐to‐surface mean interparticle distance did not change, it is proposed that in these PNs higher adhesion leads to a smaller τc value. Finally, the presence in the matrix of a nanostructured clay makes the rubber content necessary for the toughness jump to increase and τc to decrease. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3611–3620, 2005
Atomic branching in molecules
Authors: Estrada Ernesto , Rodríguez‐Velázquez Juan A. , Randić Milan 
Published: November 2005

AbstractA graph theoretic measure of extended atomic branching is defined that accounts for the effects of all atoms in the molecule, giving higher weight to the nearest neighbors. It is based on the counting of all substructures in which an atom takes part in a molecule. We prove a theorem that permits the exact calculation of this measure based on the eigenvalues and eigenvectors of the adjacency matrix of the graph representing a molecule. The definition of this measure within the context of the Hückel molecular orbital (HMO) and its calculation for benzenoid hydrocarbons are also studied. We show that the extended atomic branching can be defined using any real symmetric matrix, as well as any Hermitian (self‐adjoint) matrix, which permits its calculation in topological, geometrical, and quantum chemical contexts. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Reactivity of acetonyl anion with nitroaromatics: an atmospheric pressure chemical ionization study
Authors: Song Yishu , Chen Hao , Cooks R. Graham 
Published: November 2005

AbstractNucleophilic attack by the acetonyl anion (CH3COCH) on highly electron‐deficient nitroaromatics such as trinitrotoluene (TNT) results in the carbon‐bonded anionic σ‐complexes (Meisenheimer complexes). The complexes are generated at atmospheric pressure with relatively low internal energy and do not dissociate under atmospheric pressure chemical ionization conditions, but can be dissociated upon collisional activation to produce characteristic nitrobenzyl‐substituted acetonyl anions via elimination of HNO2. Further fragmentation produces deprotonated nitrotoluene anions through the loss of CH2CO, while loss of CH2COCH3 and CH3COCH3 yields nitroaromatic molecular anions and their H‐loss counterparts. Hydrogen/deuterium (H/D) scrambling is observed in the fragmentation products of the [TNT · CD3COCD2]− complex to extents which vary for different fragmentation pathways. Selective Meisenheimer complex formation, together with its distinctive fragmentation pattern, supplies a highly discriminatory method for detection of TNT and related compounds. Copyright © 2005 John Wiley & Sons, Ltd.
Method for the elucidation of the elemental composition of low molecular mass chemicals using exact masses of product ions and neutral losses: application to environmental chemicals measured by liquid chromatography with hybrid quadrupole/time‐of‐flight mass spectrometry
Authors: Suzuki Shigeru , Ishii Tetsuko , Yasuhara Akio , Sakai Shinichi 
Published: November 2005

AbstractA method for elucidating the elemental compositions of low molecular weight chemicals, based primarily on mass measurements made using liquid chromatography (LC) with time‐of‐flight mass spectrometry (TOFMS) and quadrupole/time‐of‐flight mass spectrometry (LC/QTOFMS), was developed and tested for 113 chemicals of environmental interest with molecular masses up to ∼400 Da. As the algorithm incorporating the method is not affected by differences in the instrument used, or by the ionization method and other ionization conditions, the method is useful not only for LC/TOFMS, but also for all kinds of mass spectra measured with higher accuracy and precision (uncertainties of a few mDa) employing all ionization methods and on‐line separation techniques. The method involves calculating candidate compositions for intact ionized molecules (ionized forms of the sample molecule that have lost or gained no more than a proton, i.e., [M+H]+ or [M–H]−) as well as for fragment ions and corresponding neutral losses, and eliminating those atomic compositions for the molecules that are inconsistent with the corresponding candidate compositions of fragment ions and neutral losses. Candidate compositions were calculated for the measured masses of the intact ionized molecules and of the fragment ions and corresponding neutral losses, using mass uncertainties of 2 and 5 mDa, respectively. Compositions proposed for the ionized molecule that did not correspond to the sum of the compositions of a candidate fragment ion and its corresponding neutral loss were discarded. One, 2–5, 6–10, 11–20, and >20 candidate compositions were found for 65%, 39%, 1%, 1%, and 0%, respectively, for the 124 ionized molecules formed from the 113 chemicals tested (both positive and negative ions were obtained from 11 of the chemicals). However, no candidate composition was found for 2% of the test cases (i.e., 3 chemicals), for each of which the measured mass of one of the product ions was in error by 5–6.7 mDa. Copyright © 2005 John Wiley & Sons, Ltd.
Matrix‐assisted laser desorption/ionization mass spectrometry of taxanes
Authors: Armirotti Andrea , Benatti Umberto , Miele Mariangela , Damonte Gianluca 
Published: November 2005

AbstractTaxanes are biologically active compounds that have been extensively used in pharmacology for their powerful anticancer properties. High specificity and low level sensitivity for analysis of these compounds have been obtained with reversed‐phase high‐pressure liquid chromatography/mass spectrometry (RP‐HPLC/MS), but the number of applications of matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) for low molecular weight analytes is rapidly growing. A new MALDI‐MS approach for the rapid screening of a variety of taxanes and a tandem mass spectrometric (MS/MS) analysis of the most important and diagnostic taxane fragmentation pathways are proposed. A solid‐phase extraction method followed by preliminary quantification is also reported. Copyright © 2005 John Wiley & Sons, Ltd.
Evolution in software systems: foundations of the SPE classification scheme
Authors: Cook Stephen , Harrison Rachel , Lehman Meir M. , Wernick Paul 
Published: November 2005

AbstractThe SPE taxonomy of evolving software systems, first proposed by Lehman in 1980, is re‐examined in this work. The primary concepts of software evolution are related to generic theories of evolution, particularly Dawkins' concept of a replicator, to the hermeneutic tradition in philosophy and to Kuhn's concept of paradigm. These concepts provide the foundations that are needed for understanding the phenomenon of software evolution and for refining the definitions of the SPE categories. In particular, this work argues that a software system should be defined as of type P if its controlling stakeholders have made a strategic decision that the system must comply with a single paradigm in its representation of domain knowledge. The proposed refinement of SPE is expected to provide a more productive basis for developing testable hypotheses and models about possible differences in the evolution of E‐ and P‐type systems than is provided by the original scheme. Copyright © 2005 John Wiley & Sons, Ltd.
Précis of Breakdown of Will
Authors: Ainslie George 
Published: November 2005

Behavioral science has long been puzzled by the experience of temptation, the resulting impulsiveness, and the variably successful control of this impulsiveness. In conventional theories, a governing faculty like the ego evaluates future choices consistently over time, discounting their value for delay exponentially, that is, by a constant rate; impulses arise when this ego is confronted by a conditioned appetite. Breakdown of Will (Ainslie 2001) presents evidence that contradicts this model. Both people and nonhuman animals spontaneously discount the value of expected events in a curve where value is divided approximately by expected delay, a hyperbolic form that is more bowed than the rational, exponential curve.With hyperbolic discounting, options that pay off quickly will be temporarily preferred to richer but slower-paying alternatives, a phenomenon that, over periods from minutes to days, can account for impulsive behaviors, and over periods of fractional seconds can account for involuntary behaviors. Contradictory reward-getting processes can in effect bargain with each other, and stable preferences can be established by the perception of recurrent choices as test cases (precedents) in recurrent intertemporal prisoner's dilemmas. The resulting motivational pattern resembles traditional descriptions of the will, as well as of compulsive phenomena that can now be seen as side-effects of will: over-concern with precedent, intractable but circumscribed failures of self-control, a motivated (“dynamic”) unconscious, and an inability to exploit emotional rewards. Hyperbolic curves also suggest a means of reducing classical conditioning to motivated choice, the last necessary step for modeling many involuntary processes like emotion and appetite as reward-seeking behaviors; such modeling, in turn, provides a rationale for empathic reward and the “construction” of reality.
Marginal cost of operating a positron emission tomography center in a regulatory environment
Authors: Chuck Anderson , Jacobs Philip , Logus J. Wayne , Hilaire Donald St. , Chmielowiec Chester , McEwan Alexander J. B. 
Published: November 2005

Objectives: Cost studies of positron emission tomography (PET) imaging are important for resource and operational planning; the most relevant cost analysis in this regard is the marginal cost. Operating within a regulatory environment can add considerably to the costs of providing PET services. Previously published research has not examined the marginal cost structure of PET nor have they described the implications of regulatory compliance to operational costs. The purpose of this study was to conduct a comprehensive cost estimation of PET imaging with 18F-fluorodeoxyglucose (18F-FDG) to better identify the fixed and variable cost components, the marginal cost structure, and the added costs of satisfying regulatory requirements.Methods: Financial data on capital and operating expenses were collected for the PET center at the Cross Cancer Institute in Edmonton, Alberta, Canada.Results: The total per-service cost for clinical operations ranged between $7,869 (400 annual scans) and $1,231 (3,200 annual scans). The marginal cost for the center remained steady as volume increased up to the throughput capacity.Conclusions: Results indicate that economies from increased volumes did not arise. Regulatory requirements added significant costs to operating an 18F-FDG-PET center.