bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure and Thermoelastic Behavior of Synthetic Rubber/Organoclay Nanocomposites
Authors: Privalko Valery P. , Ponomarenko Sergiy M. , Privalko Eleonora G. , Schön Frank , Gronski Wolfram , Staneva Rosina , Stühn Bernd 
Published: August 2003

AbstractNanocomposites of synthetic styrene‐co‐butadiene rubber and three types of organoclay fillers were prepared by melt‐compounding and characterized by small‐angle X‐ray scattering (SAXS), differential calorimetry and stretching calorimetry. The in‐rubber structure of the organoclay particles is characterized by different degrees of intercalation with interlayer distances ranging from 3.1–4.8 nm. In contrast to the pristine rubber, all nanocomposites exhibited irreversibility of both mechanical work and heat effects in stretching/contraction cycles at fairly low elongations. Moreover, at the same filler loading both the mechanical reinforcement effect and the magnitude of specific heat effects proved strongly dependent on the degree of intercalation. In the range of low elongations, significantly earlier onsets of the heat inversion phenomenon (compared to theoretically expected), as well as the overshoots of exothermal heat effects in contraction above the endothermal heat effects in stretching for nanocomposites, suggested the contribution of structural rearrangements at the rubber/filler interface by the mechanism of chain slippage operative in both stretching and contraction regimes. In the range of high elongations, the thermoelastic behavior of nanocomposites could be accounted for quantitatively by the model, which assumed explicitly the contributions of local strain amplification for the rubber matrix and of successive decay of nanoparticle clusters with increasing strain, generating the exothermal effects of external friction between nanoparticles.Dependency on relative elongation of specific mechanical work (squares) and specific heat effects (circles) for the pristine rubber.magnified imageDependency on relative elongation of specific mechanical work (squares) and specific heat effects (circles) for the pristine rubber.
Preparation and Characterisation of Pd Nanoclusters in Hyperbranched Aramid Templates to be used in Homogeneous Catalysis
Authors: Tabuani Daniela , Monticelli Orietta , Komber Hartmut , Russo Saverio 
Published: August 2003

AbstractIn the present paper the potential use of hyperbranched (HB) aramids as metallic solution stabilisers and carriers for homogeneous catalysis is outlined. Aramids, synthesised either from A2 + B3 reagents [namely, p‐phenylenediamine (PPD) and trimesic acid (TMA)] or from an AB2 monomer [i.e., 5‐(4‐aminobenzamido)isophtalic acid, named ABZAIA], have been used to stabilise palladium nanoclusters dispersed in two solvent media, namely N,N′‐dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). The influence of the nature of the polymeric support as well as of the solvent medium on both cluster dimensions and stability of the solutions has been investigated. Indeed, the interactions between the polymeric support and the metallic precursor (PdCl2), as revealed by 1H NMR spectroscopy, involve only the amino groups of the HB aramids. Metal nanocluster dimensions and stability are strongly dependent on the polymer used as a stabilizer. Transmission electron microscopy (TEM) analysis has shown that the presence of HB polymer in the solution reduces cluster dimensions and allows the obtaining of stable systems. The low concentration of NH2 end groups in the poly(AB2) system leads to the formation of Pd particles of rather low dimensions with a high tendency to aggregate. All prepared solutions are stable under inert atmosphere for at least a month, with an improved stabilisation when using the poly(A2 + B3) system for more than five months.A TEM micrograph of poly(ABZAIA)/Pd from a DMSO solution.magnified imageA TEM micrograph of poly(ABZAIA)/Pd from a DMSO solution.
Polymers of Carbonic Acid, 33
Authors: Kricheldorf Hans R. , Böhme Sigrid , Schwarz Gert , Schultz Claus‐Ludolf 
Published: August 2003

AbstractThe interfacial, hydrolytic polycondensation of bisphenol‐A‐bischloroformate (BABC) was performed at 5 or 35 °C initial temperature with the following amines as catalysts: isoquinoline, pyridine, 4‐methylpyridine, 4‐tert‐butylpyridine, 4‐(dimethylamino)pyridine, 2,4,6‐trimethylpyridine and ethyldiisopropylamine. The reaction products were characterized by viscosity and SEC measurements and by MALDI‐TOF mass spectrometry. In all products (with the exception of 2,4,6‐trimethylpyridine‐catalyzed samples) cyclic oligo‐ and polycarbonates (identified up to masses around 15 000 Da) were found. Their content was particularly high when 4‐(dimethylamino)pyridine was used or when a neutral salt was added to pyridine catalyzed polycondensations. A higher temperature reduced both molecular weight and content of cycles regardless, if pyridine or ethyldiisopropylamine was used as the catalyst. Furthermore, equimolar amounts of bisphenol‐A and BABC were polycondensed in anhydrous dichloromethane using pyridine or ethyldiisopropylamine as the catalyst and HCl acceptors. In both cases low molar mass polycarbonates mainly consisting of even‐membered cycles were obtained. The reaction mechanisms are discussed. All results prove that both highly nucleophilic and highly basic tert‐amines can efficiently catalyze chain growth and cyclization, provided that the reaction conditions are accordingly optimized. Both chain growth and cyclization mainly occur in the organic phase.MALDI‐TOF mass spectrum of the polycarbonate prepared by pyridine promoted polycondensation of bisphenol‐A and BABC in dry CH2Cl2.magnified imageMALDI‐TOF mass spectrum of the polycarbonate prepared by pyridine promoted polycondensation of bisphenol‐A and BABC in dry CH2Cl2.
Quasi–concave envelope of a function and convexity of level sets of solutions to elliptic equations
Authors: Colesanti Andrea , Salani Paolo 
Published: August 2003

AbstractGiven a C2 function u, we consider its quasi–convex envelope u* and we investigate the relationship between D2u and D2u* (the latter intended in viscosity sense); we obtain two inequalities between the tangential Laplacian of u and u* and the normal second derivative of u and u* (the words tangential and normal are referred to a level set of the involved functions). Then we apply the result to prove convexity of level sets of solutions of elliptic equations in convex rings. Our results can be applied to a class of elliptic operator which can be naturally decomposed in a tangential and a normal part, such as Laplacian, p–Laplacian or the Mean Curvature operator. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A generalized Hankel transform on Lν,r–spaces
Authors: Glaeske Hans–Jürgen , Kilbas Anatoly A. 
Published: August 2003

AbstractAn integral transform with a kernel generalizing the Bessel function of the first kind is investigated in weighted Lp–spaces. Mapping properties, such as the boundedness, the representation and the range of the transform, are given and an inversion formula is proved. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Measures of non–compactness of classical embeddings of Sobolev spaces
Authors: Hencl Stanislav 
Published: August 2003

AbstractLet Ω be an open subset of ℝn and let p ∈ [1, n). We prove that the measure of non–compactness of the Sobolev embedding Wk,p0(Ω) → Lp*(Ω) is equal to its norm. This means that the entropy numbers of this embedding are constant and equal to the norm. The same is true, when λn(Ω) is small enough, for the embedding of W1,n0(Ω) into the Orlicz space with Young function exp(tn/(n−1) − 1. The position is different for the embedding of W1,p0(J) in C0,1−1/p($ \bar J $), J equals; (0, 1), when p ∈ (1,∞): in this case the measure of non–compactness is less than the norm. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analytic continuation and identities involving heat, Poisson, wave and Bessel kernels
Authors: Jorgenson Jay , Lang Serge 
Published: August 2003

AbstractIn this article we use classical formulas involving the K–Bessel function in two variables to express the Poisson kernel on a Riemannian manifold in terms of the heat kernel. We then use the small time asymptotics of the heat kernel on certain Riemannian manifolds to obtain a meromorphic continuation of the associated Poisson kernel to all values of complex time with identifiable singularities. This result reproves in a different setting by different means a well–known theorem due to Duistermaat and Guillemin [DG 75]. Also, we develop analytic expressions for the heat kernel beyond asymptotic expansions. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nonlinear absolutely summing mappings
Authors: Matos Mário C. 
Published: August 2003

AbstractA mapping f, defined on an open subset A of a Banach space E, with values in another Banach space F, such that (f(a + xj) −f(a))∞j=1 is absolutely summable in F, whenever (xj)∞j=1 is unconditionally summable (respectively, absolutely summable) in E, is called absolutely summing (respectively, regularly summing) at the point a ∈ A. It is proved that f is regularly summing at a if, and only if, there areM > 0 and δ > 0, such that ‖f(a + x) − f(a)‖ ≤ M ‖x‖, for all ‖x‖ ≤ δ. This result has as a consequence a characterization of absolutely summing mappings by means of inequalities. This result is analogous to the well know characterization of the linear absolutely summing mappings. Several results and examples show that the existence of non–linear absolutely summing mappings is not a rare phenomena. A Dvoretzky–Rogers Theorem for n–homogeneous polynomials is proved. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hyers–Ulam stability of linear differential operator with constant coefficients
Authors: Miura Takeshi , Miyajima Shizuo , Takahasi Sin–Ei 
Published: August 2003

AbstractLet P(z) be a polynomial of degree n with complex coefficients and consider the n–th order linear differential operator P(D). We show that the equation P(D)f = 0 has the Hyers–Ulam stability, if and only if the equation P(z) = 0 has no pure imaginary solution. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Exposed points and extremal problems in H1 on a bidisc
Authors: Nakazi Takahiko 
Published: August 2003

AbstractAn essential bounded function ϕ gives a continuous linear functional on the Hardy space H1 on the bitorus. In this paper, we consider extremal problems on H1 when ϕ is a rational function, ϕ is a product of one variable functions or ϕ = |f|/f for some outer function f in H1 such that f(z, w) has a good property with respect to w for a.e. z. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Guest editorial: Evolutionary psychology and consumption
Authors: Hantula Donald A. 
Published: August 2003

AbstractConsumer behavior is discussed as a biobehavioral phenomenon and considered in light of evolutionary theory. Current consumer choices are viewed as shaped in the environment of evolutionary adaptedness (EEA), and the expression of these evolved behavioral repertoires in modern consumer settings such as malls, grocery stores, and on‐line shopping are analyzed in terms of evolutionary psychology. A variety of empirical studies confirm that consumption conforms to predictions made from sexual strategies, reciprocal altruism, foraging, and matching theories. Further explorations of consumer behavior and marketing practices from an evolutionary psychology perspective are a promising area for future research. © 2003 Wiley Periodicals, Inc.
An evolutionary psychology perspective on gift giving among young adults
Authors: Saad Gad , Gill Tripat 
Published: August 2003

AbstractWith evolutionary psychology used as the theoretical framework, two aspects of gift giving among young adults are investigated: (a) sex differences in motives for giving gifts to a romantic partner, and (b) the allocation of gift expenditures among various relations, including romantic partners, close friends, close kin, and distant kin members. As per the evolved sex differences in mating strategies, it is proposed and found that men report tactical motives for giving gifts to their romantic partners more frequently than women. Also, there are no sex differences in situational motives for giving gifts. In addition, women are aware that men use tactical motives more often; whereas men think that these motives are employed equally by both sexes. With regard to gift expenditures it is found that, for kin members, the amount spent on gifts increases with the genetic relatedness (rvalue) of the particular kin. When all relations (kin and nonkin members) are included, the allocation of gift expenditures were the highest to romantic partners, followed by those to close kin members and then to close friends. The latter finding is explained via the importance attached to the evolved psychological mechanisms linked to each of the above relations, namely, reproductive fitness (for partners), nonreproductive fitness (for close kin members), and reciprocal altruism (for close friends). © 2003 Wiley Periodicals, Inc.
Optimal foraging online: Increasing sensitivity to delay
Authors: DiClemente Diane F. , Hantula Donald A. 
Published: August 2003

AbstractThis experiment is a replication and extension of the Rajala and Hantula (2000) study of sensitivity to feedback delay while shopping in a simulated Internet mall. The experiment consisted of three conditions: One group had an ascending clock placed on the computer screen to cue the passage of time, another group had a descending clock placed on the computer screen, and as a control and replication condition, another group had no clock on the computer screen. Participants were more sensitive to the delays in the various stores in the cybermall when an ascending clock was present on the screen. A hyperbolic discount function fit best described the number of entries into each store, amount of time spent in each store, and relative number of purchases in each store. A customer‐satisfaction survey showed decreasing positive attitudes toward the stores as a function of delay. These results have implications both in terms of foraging theory applied to human behavior, as well as for the practice of online marketing. © 2003 Wiley Periodicals, Inc.
The behavioral ecology of brand choice: How and what do consumers maximize?
Authors: Foxall Gordon R. , James Victoria K. 
Published: August 2003

AbstractMatching theory predicts choices on concurrent variable ratio schedules on which consumers' brand selection occurs will show maximization via exclusive choice of the richest schedule. However, aggregate studies of consumer choice indicate two modes of consumer brand purchase within a product category: either exclusive purchase of one brand or multibrand purchasing. This article uses brand‐selection data from individual consumers to determine whether, at this level of analysis, (a) consumers' purchasing patterns show matching, (b) consumers maximize returns, and, if so, (c) what they maximize. Consumer behavior for fast‐moving goods exhibits matching, but in the form of multibrand purchasing rather than exclusive choice. Moreover, for substitutes, brand selection is price sensitive, suggesting both melioration and maximization; for nonsubstitutes, choice is not price sensitive but still appears consistent with maximization of price‐ and nonprice‐related sources of value. © 2003 Wiley Periodicals, Inc.
Intuitive evolutionary perspectives in marketing practices1
Authors: Colarelli Stephen M. , Dettmann Joseph R. 
Published: August 2003

AbstractFirms spend considerable sums of money on marketing, and they continue to do so because marketing works. However, marketing can only work if marketers have a reasonably accurate view of human nature. It is argued that many consumer products and advertisements reflect an accurate view of human nature, a view that is compatible with the tenets of evolutionary psychology. Implicit theories of human nature that are out of synch with reality sell few products. An overview of an evolutionary perspective on marketing is provided here, and connections between marketing practices and evolved adaptations, including kin selection, prestige seeking, preferences for salt, sweets, and fat, and savanna‐like landscapes are examined. Adaptations that differ by sex and how they are mirrored in marketing are also examined. Finally, some marketing practices that reflect evolutionary principles of variation are discussed. © 2003 Wiley Periodicals, Inc.
One‐Component Bimolecular Photoinitiating Systems, 2
Authors: Aydin Meral , Arsu Nergis , Yagci Yusuf 
Published: August 2003

AbstractThe compounds 2‐thioxanthone‐thioacetic acid and 2‐(carboxymethoxy)thioxanthone, bimolecular photoinitiators for free radical polymerization, are synthesized and characterized. Their capability to act as initiators for the polymerization of methyl methacrylate was examined. The postulated mechanism is based on the intermolecular electron‐transfer reaction of the excited photoinitiator with the sulfur or oxygen atom of the ground state of the respective photoinitiator followed by decarboxylation. The resulting alkyl radicals initiate the polymerization.Structures of the photoinitiators.magnified imageStructures of the photoinitiators.
Green Nanocomposites from Renewable Resources: Biodegradable Plant Oil‐Silica Hybrid Coatings
Authors: Tsujimoto Takashi , Uyama Hiroshi , Kobayashi Shiro 
Published: August 2003

AbstractGreen nanocomposite coatings based on renewable plant oils have been developed. An acid‐catalyzed curing of epoxidized plant oils with 3‐glycidoxypropyltrimethoxysilane produced transparent nanocomposites. The hardness and mechanical strength improved by incorporating the silica network into the organic polymer matrix, and good flexibility was observed in the nanocomposite. The nanocomposites showed high biodegradability.
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Frozen‐In Magnetic Order in Uniaxial Magnetic Gels: Preparation and Physical Properties
Authors: Collin Dominique , Auernhammer Günter K. , Gavat Odile , Martinoty Philippe , Brand Helmut R. 
Published: August 2003

AbstractWe describe the preparation and characterization of uniaxial magnetic gels. Fibril formation of the embedded magnetic particles generates easily detectable magnetic and optical anisotropies. A finite magnetization is frozen‐in and leads to a ferromagnetic‐like response in small homogeneous external magnetic fields. We present, for the first time, frequency dependent measurements of the shear modulus G′. Despite their optical and magnetic anisotropy, the gels are mechanically isotropic.The time‐dependent G′ for a ferrogel in the parallel orientation in a homogeneous field of 200 mT.magnified imageThe time‐dependent G′ for a ferrogel in the parallel orientation in a homogeneous field of 200 mT.
Poly(vinyl alcohol)‐Encapsulated Hydrophilic Carbon Black Nanoparticles Free from Aggregation
Authors: Li Han‐Ying , Chen Hong‐Zheng , Sun Jing‐Zhi , Cao Jian , Yang Zheng‐Long , Wang Mang 
Published: August 2003

AbstractCarbon black (CB) nanoparticles were encapsulated by poly(vinyl alcohol) (PVA) by a simple method of coacervation. Transmission electron microscopy (TEM) images clearly demonstrated that the successful encapsulation of PVA happened at the surfaces of CB nanoparticles. The particle‐size distribution measurements indicated that the diameters of the obtained PVA‐encapsulated CB (CB@PVA) nanoparticles were distributed within the nanoscale dimension. This strategy avoids the complicated polymerization process involved in the counterpart of polymer‐coating approaches.A TEM image of PVA‐encapsulated carbon black.magnified imageA TEM image of PVA‐encapsulated carbon black.
Bis(Phenoxy‐Imine) Zr Complexes/Et3Al/Heteropoly Compound Catalyst Systems for Ethylene Polymerization
Authors: Bando Hideki , Nakayama Yasushi , Sonobe Yoshiho , Fujita Terunori 
Published: August 2003

AbstractBis(phenoxy‐imine) Zr complexes upon activation with Et3Al/(Ph3C)mHn[PMo12O40] · 8 H2O (average: m/n = 2:1) were demonstrated to be highly active catalysts for the polymerization of ethylene. One of the complexes formed narrow‐molecular‐weight distributed polyethylene ($\overline M _{\rm w} /\overline M _{\rm n}$ 1.45) with a very high activity (5640 kg‐PE · mol‐cat−1 · h−1), representing the first example of a MAO‐ and borate‐free, highly active, single‐site catalyst system based on a Group 4 transition metal complex and a heteropoly compound.Catalysis of ethylene with bis(phenoxy‐imine) Zr complexes activated with Et3Al/(Ph3C)mHn[PMo12O40] · 8 H2O.magnified imageCatalysis of ethylene with bis(phenoxy‐imine) Zr complexes activated with Et3Al/(Ph3C)mHn[PMo12O40] · 8 H2O.
AFM Study of the Self‐Assembly Behavior of Hexa‐Armed Star Polymers with a Discotic Triphenylene Core
Authors: Yu Xiang , Fu Jun , Han Yanchun , Pan Caiyuan 
Published: August 2003

AbstractThe six‐armed polystyrenes and poly(methyl methacrylate)s with a triphenylene core showed different self‐assembling patterns, isolated cylinders for polySt on mica and highly ordered cylindrical pores for polyMMA on a silicon wafer. With a decrease of polymer concentration in tetrahydrofuran (THF), the size and height of cylinders decreased for polySt, but for polyMMA, the size and depth of the cylindrical pores increased. Slow evaporation of the solvent and a low molecular weight favored the formation of regular patterns.AFM images of self‐assembling patterns of polySt 1a on mica (A) and of polyMMA 2a on silicon wafer (B).magnified imageAFM images of self‐assembling patterns of polySt 1a on mica (A) and of polyMMA 2a on silicon wafer (B).
Thermal Degradation Processes in Poly(acyl sulfides) Investigated by Pyrolysis–Gas Chromatography/Mass Spectrometry
Authors: Sundarrajan Subramanian , Srinivasan Kalathur S. V. 
Published: August 2003

AbstractA series of poly(acyl sulfides) were synthesized by polycondensation of acid dichlorides with sodium sulfide using tetrabutylammoniumhydrogen sulfate as a phase transfer catalyst. The thermal stability of these polymers was determined by thermogravimetric analysis. A unique phenomenon of exothermic degradation behavior was observed by differential thermal analyses, which is attributed to the energetics of the acylsulfide linkage during the thermal degradation. The mechanism of formation of degradation products was investigated by the pyrolysis–gas chromatography/mass spectrometry (Py‐GC/MS) technique.The acylsulfide linkage containing polymers synthesized exhibit unique degradation behavior.magnified imageThe acylsulfide linkage containing polymers synthesized exhibit unique degradation behavior.
Credit cards scoring with quadratic utility functions
Authors: Bugera Vladimir , Konno Hiroshi , Uryasev Stanislav 
Published: August 2003

AbstractThe paper considers a general approach for classifying objects using mathematical programming algorithms. The approach is based on optimizing a utility function, which is quadratic in indicator parameters and is linear in control parameters (which need to be identified). Qualitative characteristics of the utility function, such as monotonicity in some variables, are included using additional constraints. The methodology was tested with a ‘credit cards scoring’ problem. Credit scoring is a way of separating specific subgroups in a population of objects (such as applications for credit), which have significantly different credit risk characteristics. A new feature of our approach is incorporating expert judgments in the model. For instance, the following preference was included with an additional constraint: ‘give more preference to customers with higher incomes.’ Numerical experiments showed that including constraints based on expert judgments improves the performance of the algorithm. Copyright © 2003 John Wiley & Sons, Ltd.