bluuebunny/crossref_metadata_2025 huggingface dataset:
Morphology and Properties of Poly(L‐Lactide) (PLLA) Filled with Hollow Glass Beads
Authors: Hu Xiao , Xu Hong‐Sheng , Li Zhong‐Ming
Published: May 2007

The morphology, crystalline behavior, and mechanical and thermal properties of poly(L‐lactide)/hollow glass beads (PLLA/HGBs) composites were investigated. The incorporation of HGBs enhanced the crystallization rate and crystallinity of PLLA, but slightly decreased its elongation at break. In addition, HGBs acted as stress concentration points inducing the plastic deformation of PLLA, leading to increased Izod impact strength. Differential scanning calorimetry results show that annealed PLLA eliminated cold crystallization phenomenon in the region of 100–140 °C and presented a double melting peak around 150 °C. Moreover, annealing was demonstrated to be effective for the improvement of tensile modulus, strength, Izod impact strength and heat distortion temperature of the composites due to the increased crystallinity and more perfect crystals. Silane coupling agents can enhance the interfacial adhesion of the composites, and lead to better mechanical properties. Compared to neat PLLA, the HGBs filled PLLA composites did not exhibit an obvious increase of the density.

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Introduction of a New Coupling Agent for Selective Coupling of Hydroxy and Amino Group‐Containing Polymers
Authors: Jakisch Lothar , Komber Hartmut , Böhme Frank
Published: May 2007

A new bifunctional coupling agent with an oxazinone and a lactamate group is synthesized. It is shown by means of model reactions that in the presence of aliphatic hydroxy compounds the reaction of the coupling agent is highly selective. At 220 °C, a conversion of the lactamate group of about 90% is observed under elimination of lactam. In a second reaction the oxazinone group is converted with an aliphatic amino compound. This high selectivity is utilized in the synthesis of segmented polyester/polyamide block copolymers by sequential conversion of the coupling agent with hydroxy‐terminated polyesters [poly(butylene terephthalate) (PBT) and polycaprolactone (PCL)] and amino‐terminated polyamide 12 (PA12) under the conditions of reactive extrusion. In the case of the PA12/PBT block copolymer, ductile behavior is observed, whereas the PA12/PCL block copolymer shows elastic properties. Both polymers are phase separated on the nanometer‐scale, as evidenced by AFM and SEM. The thermal behavior of the polymers is affected by the influence of the individual blocks.

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Weighted Tent Spaces
Authors: Soria Javier
Published: May 2007

We generalize the theory of tent spaces introduced in [9] and [10], to consider weighted norms related to some function parameters (see [11]). We study their atomic decomposition, from which we obtain a weighted inequality for a certain fractional maximal operator. We also find the dual spaces, and get a new class of CARLESON measures and we identify the intermediate spaces when using several methods of interpolation.
Extensions of Unbounded Representations
Authors: Inoue Atsushi , Kurose Hideki , Ǒta Schǒichi
Published: May 2007

Induced extensions of unbounded (non *‐preserving, in general) representations of a *‐algebra are studied and some elementary facts are shown. For further study of *‐representation of non‐commutative *‐algebra, we introduce twisted extensions of *‐representations as a generalization of induced extensions. And we show that the SCHRÖDINGER representation of a WEYL‐algebra can be realized as a twisted extensions for any its *‐subrepresentation.
Über die Veränderung konformer Gebietsgrößen bei quasikonformer Abbildung
Authors: Kirsch Siegfried
Published: May 2007

Es wird ein neuer Typ von Extremalproblemen bei quasikonformen Abbildungen behandelt, bei denen das zugehörige quadratische Differential eine stückweise analytische Funktion darstellt.

Für eine spezielle Klasse quasikonformer Abbildungen wird ein Verfahren vorgestellt, das zu asymptotisch scharfen Abschätzungen der Funktionalwerte führt, falls die Dilatation der quasikonformen Abbildungen nur wenig von 1 abweicht.
A New Integral Geometric Formula of the Blaschke‐Petkantschin Type
Authors: Vedel Jensen E. B. , Kiê K.
Published: May 2007

Recently, a new geometric measure decomposition has been derived by Zähle (1990), involving the r‐fold product of the d‐dimensional Hausdorff measure with itself. The application to moment measure estimation has been discussed in Jensen et al. (1990a) and Zähle (1990). The decomposition involves, in essence, the rotational invariant measure on r‐dimensional linear subspaces in Rn and the r‐fold product of the (d ‐ n + r)‐dimensional Hausdorff measure. In the present paper, we derive another decomposition of this type, involving linear subspaces containing a fixed lower‐dimensional linear subspace. The formula has applications in geometric sampling.
A Coarea Formula for Multiple Geometric Integrals
Authors: Kiêu K.
Published: May 2007

The coarea formula by Federer (1969) is a general transformation formula for simple geometric integrals. In the present paper, we derive a coarea formula for multiple geometric integrals. The construction of this new formula is based on the use of the simple coarea formula on a product of Hausdorff rectifiable sets. Also, this coarea formula for multiple integrals is extended, so it can be applied to the locally Hausdorff rectifiable sets described in Zähle (1982). An application of the formula resulting in new Blaschke‐Petkantschin formulae is presented in Jensen and Kiêu (1991).
Some Characterizations of Ergodic Probability Measures
Authors: Adamski Wolfgang
Published: May 2007

Let P be a Markov kernel defined on a measurable space (X, 𝒜). A P‐ergodic probability is an extreme point of the family of all P‐invariant probability measures on 𝒜. Several characterizations of P‐ergodic probabilities are given. In particular, for the special case of a topological space X both P‐ergodic Baire probabilities and P‐ergodic Borel probabilities with additional regularity properties are characterized.
Über ein Extremalproblem bei im Mittel quasikonformen Abbildungen
Authors: Kirsch Siegfried
Published: May 2007

Es werden notwendige Bedingungen, eine hinreichende Bedingung und ein Unitätskriterium für Extremalfunktionen zu einem Extremalproblem bei Q(z)‐quasikonformen Abbildungen angegeben, deren Dilatation im Mittel beschränkt ist und auf einer vorgegebenen Teilmenge nur vorgeschriebene Werte annimmt. Die Anwendung der hinreichenden Bedingung zur Konstruktion von Extremalfunktionen wird an Beispielen demonstriert.
Central Limit Theorems for Markov‐Connected Random Variables
Authors: Liebscher E.
Published: May 2007

The paper provides some central limit theorems for triangular arrays of Markov‐connected random variables. It is assumed the Markov chain to satisfy condition (D1) which is an generalization of strong Doeblin's condition (Do). One result represents a central limit theorem without the assumption of finite variances.
Kernel Properties and Representations of Boundary Integral Operators
Authors: Schwab C. , Wendland W. L.
Published: May 2007

Boundary integral operators arise in the reduction to the boundary method for solving elliptic boundary value problems. These are classical pseudodifferential operators of integer order on the boundary. In order to exploit these boundary integral operators for computational methods one needs explicit knowledge of the corresponding kernel properties in the framework of Hadamard finite part regularization, explicit representation based on local polar coordinates and explicit transformation under the change of the parametric representation of the boundary manifold. Here we present these properties for the special case of a (piecewise) smooth two‐dimensional boundary surface immersed into ℝ3.
Boundedly Compatible Webs and Strict Mackey Convergence
Authors: Gilsdorf Thomas E.
Published: May 2007

We look for characterizations of those locally convex spaces that satisfy the strict Mackey convergence condition within the context of spaces with webs. We will say that a locally convex space has a boundedly compatible web if it has a web of absolutely convex sets whose members behave like zero neighborhoods in a metrizable locally convex space. It will be shown that these locally convex spaces satisfy the strict Mackey convergence condition. One consequence of this result will be a characterization of boundedly retractive inductive limits. We will also prove that if E is locally complete and webbed, then the strict Mackey convergence condition is equivalent to E having a boundedly compatible web.
Disjointness of Lattice Elements
Authors: Saarimäki Mikko
Published: May 2007

We examine the relations between various disjointness properties in lattices with least elements, and in special lattices like section semicomplemented lattices and section complemented lattices.
On the Structure of Hv0(D) and hv0(D)
Authors: Lusky Wolfgang
Published: May 2007

Weighted spaces of harmonic and holomorphic functions on the unit disc are discussed. It is shown that these spaces are always subspaces of c0. Moreover, for many weights, it is shown that the weighted space of holomorphic functions has a basis.
Toward a Unified Theory of Generalized Functions: Convergence
Authors: Mikusiński Piotr , Taylor Michael D.
Published: May 2007

Generalized functions are usually treated as bounded linear functionals on spaces of test functions. Here they are considered as objects which „convolute”︁ with test functions and satisfy a certain associativity condition. In this setting simple definitions are given for convergence of sequences of test functions and generalized functions, definitions which do not depend on particular properties of the space of test functions. It is shown that for the most commonly used spaces, these general definitions reduce to the standard ones.
A Note on the Type of Local von Neumann Algebras in Quantum Field Theory over Curved Space‐time
Authors: Wollenberg Manfred
Published: May 2007

It is shown that there are relations between the Connes invariant for local v. Neumann algebras belonging to different curved space‐times provided these local algebras are connected by a certain asymptotic condition. This asymptotic condition is implied by a scaling limit condition as well as by a condition of connectedness by large translations.
Generalized Brownian Motion, Point Processes and Stochastic Calculus for Random Fields
Authors: Fichtner K.‐H. , Winkler G.
Published: May 2007

A representation of the Malliavian derivative and the Skorochod integral in terms of random point systems on Polish spaces (and thus generalizing from the unit interval) is derived. This leads to a stochastic calculus based on random point systems. The operators are given explicitely and in a simple form allowing concrete probabilistic and quantum probabilistic interpretations.
On the Reconstruction Problem in Superselection Theory
Authors: Baumgärtel Hellmut
Published: May 2007

The paper presents a new construction of crossed products of C*‐algebras 𝒜 and group duals (of compact groups) acting on 𝒜 using a suitable 𝒜‐left module as the starting object.
The Stability and the Convergence of a Collocation Method for a Class of Cauchy Singular Integral Equations
Authors: Capobianco Maria Rosaria
Published: May 2007

The author proves the stability and the uniform convergence of a collocation method for solving Cauchy singular integral equations with regular pertubation kernel. Error estimates in the uniform norm are also given.
Construction of Corner Singularities for Agmon‐Douglis‐Nirenberg Elliptic Systems
Authors: Costabel Martin , Dauge Monique
Published: May 2007

Corner singularities in plane domains are characterized by certain singular exponents and angular functions. Our construction of singularities is based on two Cauchy integrals at two different levels of symbolic calculus. This construction yields new information about the angular functions and also more explicit formulas for the computation of the singular exponents.
Ergänzungsgesetze
Authors: Burde Klaus
Published: May 2007

Für rationale Primzahlen p, q mit q  1(pk) wird unter der Voraussetzung, daß p zumindest pk‐1‐ter Potenzrest modulo q ist, in §2 ein Kriterium dafür hergeleitet, daß p ein pk‐ter Potenzrest modulo q ist. Solche Kriterien wurden für k = 1 und beliebiges p von ANKENY in [1] sowie von Muskat in [8] und [9] angegeben. Für p = 2 und beliebiges k bewies Evans in [6] ein entsprechendes, von Muskat in [10] vermutetes Kriterium. Das hier aufgestellte Kriterium (2.10), (2.10') stimmt für k = 1 mit dem von ANKENY überein, hat für p = 2 jedoch eine andere Form als das von Muskat‐Evans.

In einem vorbereitenden §1 wird der zur Herleitung unseres Kriteriums geeignete Rechenbereich vorgestellt, §3 enthält Auswertungsbeispiele. Einige für das Verständnis nicht wesentliche Beweise sind in einem Anhang zusammengestellt, auf den mit A* verwiesen wird.
On Finite Krutik‐Groups
Authors: Brandl R. , Deaconescu M.
Published: May 2007

The structure of the finite Krutik‐groups is investigated. It is shown that they are solvable groups with very special properties.
Symmetry Groups of Coloured Graphs
Authors: Baumann Ulrike
Published: May 2007

A perfect colouring Φ of a simple undirected connected graph G is an edge colouring such that each vertex is incident with exactly one edge of each colour. This paper concerns the problem of representing groups by graphs with perfect colourings. We define groups of graph automorphisms, which preserve the structure of the colouring, and characterize these groups up to isomorphism. Our considerations are based on the fact that every perfectly coloured graph is isomorphic to a Schreier coset graph on a group generated by involutions.
On Colouring Partial Joins of a Complete Graph and a Cycle
Authors: Stiebitz M. , Wessel W.
Published: May 2007

Define the partial join of two graphs to be some graph arising from their disjoint union by adding a set of new edges each joining a vertex of the first graph and a vertex of the second one. We characterize all colour‐critical graphs being partial joins of a complete graph and an odd cycle thus completely answering a special case of a question raised by T. GALLAI in 1969.
Analysis of a Distinguished Laplacian on Solvable Lie Groups
Authors: Giulini Saverio , Mauceri Giancarlo
Published: May 2007

We study a class of kernels associated to functions of a distinguished Laplacian on the solvable group AN occurring in the Iwasawa decomposition G = ANK of a noncompact semisimple Lie group G. We determine the maximal ideal space of a commutative subalgebra of L1, which contains the algebra generated by the heat kernel, and we prove that the spectrum of the Laplacian is the same on all Lp spaces, 1 ≤ p < ∞. When G is complex, we derive a formula that enables us to compute the Lp norm of these kernels in terms of a weighted Lp norm of the corresponding kernels for the Euclidean Laplacian on the tangent space. We also prove that, when G is either rank one or complex, certain Hardy‐Littlewood maximal operators, which are naturally associated with these kernels, are weak type (1, 1).
Modular Interval Spaces
Authors: Bandelt H.‐J. , van de Vel M. , Verheul E.
Published: May 2007

Modular interval spaces represent a common generalization of Banach spaces of type L1(μ) or B(X), of hyperconvex metric spaces, modular lattices, modular graphs, and median algebras. It turns out that several types of structures are susceptible for a notion capturing essential features of modularity in lattices, e.g., semilattices, multilattices, metric spaces, ternary algebras, and graphs. There is no perfect correspondence between modular structures of various types unless the existence of a neutral point is imposed. Modular structures with neutral points embed in modular lattices. Particular modular interval spaces (e.g., median spaces, or more generally, modular spaces in which intervals are lattices) can be characterized by forbidden subspaces.
Besov Spaces of M‐harmonic Functions on Bounded Symmetric Domains
Authors: Hahn K. T. , Youssfi E. H.
Published: May 2007

New Besov spaces of M‐harmonic functions are introduced on a bounded symmetric domain in ℂn. Various characterizations of these spaces are given in terms of the intrinsic metrics, the Laplace‐Beltrami operator and the action of the group of the domain.
Measure‐valued Solutions of the Euler and Navier‐Stokes Equations for Compressible Barotropic Fluids
Authors: Neustupa Jiří
Published: May 2007

The notion of a measure‐valued solution for the Euler and the Navier‐Stokes equations is introduced and its global in time existence is proved.
Some Further Properties of Kählerian Twistor Spinors
Authors: Kirchberg K.‐D.
Published: May 2007

On a spin Kähler manifold M2m a new first integral QΨ of the Kählerian twistor equations is presented. If the scalar curvature has a critical point then QΨ vanishes. In case M2m is closed, this fact provides a simple geometrical obstruction for Kählerian twistor spinors and, consequently, some new vanishing theorems. Twistor spinors with QΨ ≠ 0 are investigated. Some invariants of the corresponding space of twistor spinors are constructed if the other basic first integral CΨ does not vanish, too. Each twistor spinor Ψ with CΨ ≠ 0 and QΨ ≠ 0 determines a foliation of M2m whose leaves are totally geodesic immersed Kähler manifolds. It is shown that Kählerian twistor spinors of type (r, s) can be interpreted as the minima of a certain functional. Some properties of Kählerian twistor spinors of the exceptional type r = (m + 2)/2 are proved.
Rings with Approximation Property Admit a Dualizing Complex
Authors: Hinich V.
Published: May 2007

Let A be a commutative Noetherian local ring satisfying the approximation property. This means that any system of polynomial equations over A having a solution in the completion Ǎ has also a solution in A. Then A is proven to admit a dualizing complex.
On Lyapunov Exponents and Rotation Number of Random Linear Hamiltonian Systems
Authors: Teichert Heidrun
Published: May 2007

We consider linear Hamiltonian differential systems in R2n depending on a stationary ergodic Markov process. The induced processes on the Lagrangian manifolds Lp and Lp−1, p (1 ≦ p ≦ n) are studied. From this we derive representations for the Lyapunov exponents, especially the lowest non‐negative exponent, and a (suitably defined) rotation number of the system.
Stability and Convergence of a Hyperbolic Tangent Method for Singular Integral Equations
Authors: Venturino Ezio
Published: May 2007

In this paper we reexamine a previously proposed quadrature scheme, [VENTURINO], based on a formula proposed in [STENGER, 1976]. Our goal is to establish a stability result for the dominant singular integral equation of index one, and from it derive the error analysis for the proposed numerical method. The convergence of the method can then be extended to the first kind complete equation and to the equation of index zero. Finally the modifications necessary for applying this analysis to a recently proposed scheme for Hadamard finite part integral equations are examined. In all these proofs the necessary assumption we need to make is to restrict our considerations to a compact subset of the interval in which the equation is formulated, containing all the nodes where the unknown is evaluated.
Asymptotic Behaviour of Neutral Differential Equations with Distributed Delay
Authors: Bainov D. , Petrov V.
Published: May 2007

In the paper the asymptotic behaviour of the solutions of a class of neutral differential equations with distributed delay is studied.
Real Analytic Fibre Bundles: Some Results on Classification and Homotopies
Authors: Guaraldo F.
Published: May 2007

The classification problem for holomorphic fibre bundles over Stein spaces was solved by H. GRAUERT. Along the same lines, the real coherent analytic case was considered by A. TOGNOLI and V. ANCONA.

In this paper we propose a different approach, based on classifying spaces, in order to study the previous problem for real analytic fibre bundles over C‐analytic subspaces of Rm.

So, let X be a C‐analytic subspace of Rm and G a compact Lie group. The main result is a characterization of the real analytic G‐principal fibre bundles over X for which the analytic and topological equivalence coincide.

Moreover, we prove that these bundles can be classified also by means of homotopy classes of analytic maps of X into classifying spaces.

Among the others results, are worth recording: a relative approximation theorem of continuous cross sections by analytic ones, a theorem about the equivalence between analytical and topological homotopy between cross sections and a covering homotopy theorem.
On the Distributional Index 2F1‐transform
Authors: Hayek N. , González B. J.
Published: May 2007

In this paper the index 2F1‐transform is defined on a space of generalized functions by using the method of adjoints. We prove that smooth functions having suitable asymptotic behaviors around zero and infinite are 2F1‐transforms of generalized functions.
On the Existence of Radial Solutions of a Nonlinear Elliptic BVP in an Annulus
Authors: Cheng Yuanji
Published: May 2007

In this paper we study the radial solutions of quasilinear elliptic BVP:

on A, u satisfies the Robin boundary conditions (2) below, where A = {x∈Rn; a1 < |x| < a2}, a2 > a1 > 0, constants. Under the very general conditions, we prove that if f is superlinear at u = ∞, then (*) admits infinitely many radial solutions, and that each of them has a different (finite) number of zeros.
The Conformal Arclength Functional
Authors: Musso Emilio
Published: May 2007

A generic smooth curve of the three dimensional Möbius space admits a natural parameter (or conformal arclength). Integrating the conformal arclength we get a conformally invariant variational problem. In the present paper we study the extremal curves of this variational problem. We derive the associated Euler‐Lagrange equations and we get the natural equations of the extremal curves. The natural equations are integrated and the explicit solutions are given.
Some Remarks on Krein's Extension Theory
Authors: Brasche J. F. , Neidhardt H.
Published: May 2007

The extension problem of semibounded symmetric operators and symmetric operators with a gap is studied in detail. Using a suitable representation (Krein model) for the inverses of those operators a parameterization of their symmetric and self‐adjoint extensions is introduced which improves Krein's famous extension theory. In particular, the parameterization clearly shows which self‐adjoint extensions in the gap case correspond to Friedrichs and v. Neumann or Krein extensions in the semibounded case. Moreover, special properties of the extensions as the exactness of the gap are characterized in terms of the parameters.
On the Spectral Flow of Families of Dirac Operators with Constant Symbol
Authors: Bunke Ulrich
Published: May 2007

We consider families of generalized Dirac operators Dt with constant principal symbol and constant essential spectrum such that the endpoints are gauge equivalent, i.e., D1 = W*D0W. The spectral flow un any gap in the essential spectrum we express as the Fredholm index of 1 + (W ‐ 1)P where P is the spectral projection on the interval d, ∞) with respect to D0 and d is in the gap. We reduce the computation of this index to the Atiyah‐Singer index theorem for elliptic pseudodifferential operators. We find an invariant of the Riemannian geometry for odd dimensional spin manifolds estimating the length of gaps in the spectrum of the Dirac operator.
Notes on Embedding Theorems for Local Hardy spaces
Authors: Mizuhara Takahiro
Published: May 2007

In this note we establish an embedding theorem (Theorem 2.4) for local Hardy spaces in the sense of GOLDBERG [G]. This result is a non‐homogeneous version of the theorem of BAERNSTEIN and SAWYER (Theorem BS). Also applying this theorem we establish embedding theorem and Fourier embedding theorem (Theorem 4.2, Theorem 4.3 and Corollary 4.4) for local Hardy spaces.
Hypersingular Integrals of Marchaud Type and the Inversion Problem for Potentials
Authors: Rubin Boris
Published: May 2007

In 1927 A. MARCHAUD defined a fractional derivative of a function of one variable in the form of the integral containing the finite difference of this function. The purpose of the paper is to show that this idea can be generalized to become a foundation of the general method which enables to invert and to characterize a wide class of potential type operators with a semigroup property arising in analysis and in mathematical physics. This method leads to hypersingular integrals (HSI's), by means of which one can construct both explicit and stable approximate inverses to potentials. The paper contains the description and the justification of the method as well as its applications to various important one‐ and multidimensional potentials.
On the Metrizability of Fuzzy Neighborhood Spaces
Authors: Flüshöh Wolfgang
Published: May 2007

A fuzzy neighborhood space is said to be pseudometrizable if, and only if, the associated fuzzy topology is induced by a probabilistic pseudometric under.

By the aid of the concept of quasi‐inverse functions it will be shown that a fuzzy neighborhood space is pseudometrizable if, and only if, every associated level‐topology is pseudometrizable and a family of generating pseudometrics is monotone decreasing.
Application of Polymerization Kinetic Modeling in High‐Throughput Screening of Catalyst Systems for Productivity
Authors: Beigzadeh Daryoosh
Published: May 2007

In high‐throughput research, it is essential to use “right data” and “meaningful parameters” to reach reliable conclusions. The complexity and the large amount of data obtained from each set of experiments make the analysis of reaction data a nontrivial task. The important role of reaction kinetic modeling in the analysis of polymerization reaction data is discussed, and it is shown that the application of traditional methods for the determination of catalyst productivity can be misleading. Reaction kinetic modeling provides meaningful parameters for data analysis, gives complete information about the polymerization kinetic profile, and makes it possible to evaluate assumptions and hypotheses.

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Estimation of the Polymerization Rate of Liquid Propylene Using Adiabatic Reaction Calorimetry and Reaction Dilatometry
Authors: Ali Mohammad Al‐haj , Betlem Ben , Roffel Brian , Weickert Günter
Published: May 2007

The use of pressure‐drop and constant‐pressure dilatometry for obtaining rate data for liquid propylene polymerization in filled batch reactors was examined. The first method uses reaction temperature and pressure as well as the compressibility of the reactor contents to calculate the polymerization rate; in the second, the polymerization rate is calculated from the monomer feed rate to the reactor. Estimated polymerization rates compare well to those obtained using the well‐developed isoperibolic calorimetry technique, besides pressure‐drop dilatometry provides more kinetic information during the initial stages of the polymerization than the other methods.

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Modelling Induced Tension in a Growing Catalyst/Polyolefin Particle: A Multi‐Scale Approach for Simplified Morphology Modelling
Authors: Di Martino Audrey , Weickert Günter , Sidoroff François , McKenna Timothy F. L.
Published: May 2007

A multi‐scale modelling approach is proposed as a means of eventually overcoming the limitations of the multigrain and polymer flow models of particle growth. It is demonstrated that there is a need to introduce some sort of macroheterogeneity into the evolution of the stress build‐up in the growing macroparticles in order to see a local rupture of the particle structure. Different simulations are proposed and qualitatively compared to previously published experimental results in order to validate the approach.

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Accelerated Silane Water‐Crosslinking Kinetics of Ethylene–Propylene Copolymer by Boron Trifluoride Complexes
Authors: Adachi Kenta , Hirano Tomoyuki , Fukuda Katsuhito , Nakamae Katsuhiko
Published: May 2007

The hydrolysis and overall water‐crosslinking kinetics of vinyltrimethoxysilane‐grafted ethylene–propylene copolymer (EPR‐g‐VTMS) containing boron trifluoride monoethylamine complex (BF3–MEA), boron trifluoride methanol complex (BF3–MeOH), or di‐n‐butyltin(II) dilaurate (DBTL) as a silane‐crosslinking catalyst was followed by ATR‐FT‐IR and measuring the gel fraction, respectively. Kinetics results by ATR‐FT‐IR technique showed that using BF3–MEA provided much lower activation energy for the hydrolysis reactions than that of DBTL; however, BF3–MeOH had little catalytic effect on both the hydrolysis and overall water‐crosslink reaction of EPR‐g‐VTMS. We propose that the actual catalytic effect of ethylamine molecule dissociated from BF3–MEA results in the displacement of SiOCH3 groups via an SN2‐Si mechanism.

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The Kinetic Modeling of Strong Diffusion‐Limited Reaction with Cyclization for Three Isomers – Diallyl Ortho‐, Iso‐ and Tere‐Phthalate in a Bulk
Authors: Hace Iztok
Published: May 2007

Free radical polymerization kinetic in a bulk for three diallyl phthalate isomers – diallyl orthophthalate, diallyl isophthalate and diallyl terephthalate was investigated in a temperature range from 50 to 70 °C initiated with dicyclohexan peroxydicarbonate as initiator at three different initiator concentrations. Conversion points were measured using Fourier Transform Raman measurements. A new kinetic model for polymerization of three diallyl phthalate isomers was developed. It demands the inclusion of only two new kinetic parameters kDegC and kpc which were obtained as a ratio kDegC/kpc from an additional set of experiments conducted. Computed conversions from the proposed kinetic model show good agreement with the conversion and molecular weight measured data for all three investigated diallyl phthalate isomers.

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In‐Reactor Compounding Metallocenic Isotactic Poly(propylene)/Nucleation Agent Compositions by Employing the Nucleation Agent as a Catalyst Support
Authors: Yi Qing‐Feng , Wen Xiao‐Jing , Dong Jin‐Yong , Han Charles C.
Published: May 2007

A nucleation agent, 1,3,2,4‐dimethylbenzylidene sorbitol (DMBS), was used as a support for C2‐symmetric metallocene rac‐Me2Si[2‐Me‐4‐Naph‐Ind]2ZrCl2. Propylene polymerization with the supported catalyst resulted in i‐PP polymers with granular morphology. The role of a catalyst support ensures a good dispersion of the nucleation agent in the formed i‐PP matrix. The employment of a nucleation agent as catalyst support provides a unique solution to in‐reactor compounding metallocenic i‐PP/nucleation agent compositions.

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Long term partial bladder outlet obstruction induced contractile dysfunction in male rabbits: A role for Rho‐kinase
Authors: Guven Ahmet , Onal Bulent , Kalorin Carmin , Whitbeck Catherine , Chichester Paul , Kogan Barry , Levin Robert , Mannikarottu Anita
Published: May 2007

Aims

In this study we examined the expression of Rho‐kinase (ROK) isoforms in rabbit detrusor smooth muscle during the progression of partial bladder outlet obstruction and correlated them with the time course of obstruction.

Methods

Detrusor samples were obtained from bladders after 1, 2, 4, and 8 weeks of obstruction and also sham operated control rabbits. Contractile responses to field stimulation (FS) and also the smooth muscle (SM) to collagen ratio were determined in isolated bladder strips. Reverse transcriptase‐polymerase chain reaction, sodium dodecyl sulfate‐polyacrylamide gel electrophoresis and Western blotting were used to determine the relative levels of ROK isoform expression at the mRNA and protein levels.

Results

Bladder weight increased gradually and contractile responses were reduced significantly over the course of obstruction. The smooth muscle/collagen ratio increased significantly during the course of obstruction. The expression of ROKα increased significantly to approximately the same extent in 1–4‐week obstructed groups and increased further in the 8‐week obstructed group, both at the mRNA and protein levels. In contrast, there was a significant decrease in the expression of ROKβ in the obstructed groups, which gradually decrease during the course of 1–4‐week obstruction period and are slightly upregulated at the decompensated stage at 8‐week obstruction.

Conclusions

The change in the isoforms of ROK may be part of the molecular mechanism for bladder compensation following partial bladder outlet obstruction. Neurourol. Urodynam. 26:1043–1049, 2007. © 2007 Wiley‐Liss, Inc.
Progress instrument
Authors: Henning Emily
Published: May 2007

Minneapolis Downtown Council has been major force in reviving planning for a better city.
Wisconsin home rule
Authors: Hagensick A. Clarke
Published: May 2007

Legislative interference, willingness of local officials to yield powers corollary factors.
Extended digital image correlation with crack shape optimization
Authors: Réthoré Julien , Hild François , Roux Stéphane
Published: May 2007

The methodology of eXtended finite element method is applied to the measurement of displacements through digital image correlation. An algorithm, initially based on a finite element decomposition of displacement fields, is extended to benefit from discontinuity and singular enrichments over a suited subset of elements. This allows one to measure irregular displacements encountered, say, in cracked solids, as demonstrated both in artificial examples and experimental case studies. Moreover, an optimization strategy for the support of the discontinuity enables one to adjust the crack path configuration to reduce the residual mismatch, and hence to be tailored automatically to a wavy or irregular crack path. Copyright © 2007 John Wiley & Sons, Ltd.
Micromechanics for fiber volume percent with a photocure vinyl ester composite
Authors: Petersen Richard C. , Lemons Jack E. , McCracken Michael S.
Published: May 2007

Micromechanics for fiber volume percent (Vf) from 0.0Vf to 54.0 Vf were conducted using (3 mm long × 9 μm diameter) high‐purity quartz fibers in a visible‐light vinyl ester particulate‐filled photocure resin. MTS fully articulated four‐point bend fixtures were used with a 40 mm test span and 50 × 2 × 2 mm3 sample dimensions. Specimens were tested following the combined modified ASTM standards for advanced ceramics ASTM‐C‐1161–94 and polymers ASTM‐D‐6272–00 for modulus, flexural strength, and yield strength. Experimental data provided reliable statistical support for the dominant fiber contribution expressed through the rule‐of‐mixtures theory as a valid representation of micromechanical physics. The rule‐of‐mixtures micromechanics described by Vf could explain 92, 85, and 78% of the variability related to modulus, flexural strength, and yield strength respectively. Statistically significant improvements with fiber addition began at 10.3Vf for modulus, 5.4Vf for flexural strength, and 10.3Vf for yield strength, p < 0.05. In addition, correlation matrix analysis was performed for all mechanical test data. An increase in Vf correlated significantly with increases in modulus, flexural strength, and yield strength as measured by the four‐point bending test, p < 10−10. All mechanical properties in turn correlated highly significantly with one another, p < 10−9. POLYM. COMPOS., 28:294–310, 2007. © 2007 Society of Plastics Engineers
Fracture toughness micromechanics by energy methods with a photocure fiber‐reinforced composite
Authors: Petersen Richard C. , Lemons Jack E. , McCracken Michael S.
Published: May 2007

A fracture toughness analysis for discontinuous fiber reinforcement was evaluated as a function of fiber volume percent (Vf) using advanced flexural bend tests. Fully articulated fixtures with 40‐mm spans were used to examine specimens (2 × 2 × 50 mm3) under conditions of Euler‐type bending to reduce shearing effects. Testing for fracture toughness in standardized international units (kJ/m2) using fundamental mechanics‐of‐materials energy methods by strain energy was then applied for assessment of resilience and work of fracture (WOF). Fracture toughness was also measured as strain energy release (SERIC) for the condition of unstable fracture between peak load and 5% maximum deflection past peak load. Energies were calculated by numerical integration using the trapezoidal rule from the area under the load–deflection curve. Fracture depths were normalized using sample dimensions from microscopy imaging for a combined correlation matrix analysis of all mechanical test data. Vf significantly correlated with resilience, WOF, and SERIC, but negatively correlated with degree of crack depth with p < 0.0000005. All measured interrelated properties also significantly correlated with one another (p < 0.000001). Significant fracture toughness differences between particulate‐filled and fiber‐reinforced composites began when adding fiber reinforcement at 10.3 Vf for resilience, 5.4 Vf for WOF, and 5.4 Vf for SERIC (p < 0.05). POLYM. COMPOS., 28:311–324, 2007. © 2007 Society of Plastics Engineers
Optimisation of an extraction procedure and chemical characterisation of Croatian propolis tinctures
Authors: Cvek J. , Medić‐Šarić M. , Jasprica I. , Zubčić S. , Vitali D. , Mornar A. , Vedrina‐Dragojević I. , Tomić S.
Published: May 2007

Three spectrophotometric methods for the quantitative determination of different flavonoid groups and total phenolics in Croatian propolis samples were optimised and validated. The assay based on the formation of aluminium chloride complex (with galangin as a standard) was applied to the quantification of flavones and flavonols, while the 2,4‐dinitrophenylhydrazine method (with pinocembrine as a reference) was used for the quantification of flavanones. Total phenolic content was measured by the Folin–Ciocalteau method using reference solution of caffeic acid:galangin:pinocembrine (1:1:1). Through analytical validation, the most suitable extraction conditions (with respect to time, temperature and concentration of extraction solvent) were determined, and final conditions for the extraction were established (80% ethanol, 1 h at the room temperature). The appropriate ratio between the mass of raw propolis and the extraction solvent volume was also established. By the application of the optimised method of extraction, 10 propolis tinctures were prepared and subjected to the analysis of general pharmacopoeial parameters, which are fundamental for the creation of quality specification (relative density, dry residue of extract, content of ethanol, methanol and 2‐propanol). Additionally, the content of waxes as the main inactive constituents was determined in order to observe the level of their migration from crude propolis to the prepared tinctures. Copyright © 2007 John Wiley & Sons, Ltd.
The problem of interoperability: A common data format for quantum chemistry codes
Authors: Angeli C. , Bendazzoli G. L. , Borini S. , Cimiraglia R. , Emerson A. , Evangelisti S. , Maynau D. , Monari A. , Rossi E. , Sanchez‐Marin J. , Szalay P. G. , Tajti A.
Published: May 2007

A common format for quantum chemistry (QC), enhancing code interoperability and communication between different programs, has been designed and implemented. An XML‐based format, QC‐ML, is presented for representing quantities such as geometry, basis set, and so on, while an HDF5‐based format is presented for the storage of large binary data files. Some preliminary applications that use the format have been implemented and are also described. This activity was carried out within the COST in Chemistry D23 project “MetaChem,” in the Working Group “A meta‐laboratory for code integration in ab initio methods.” © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Characterization of the chemical components on the surface of different solids with electrospray‐assisted laser desorption ionization mass spectrometry
Authors: Huang Min‐Zong , Hsu Hsiu‐Jung , Wu Chen‐I , Lin Shu‐Yao , Ma Ya‐Lin , Cheng Tian‐Lu , Shiea Jentaie
Published: May 2007

In this study we demonstrate that electrospray‐assisted laser desorption ionization (ELDI) mass spectrometry (MS) can be used to rapidly characterize major chemical components on the surfaces of different solids under ambient conditions. The major chemical components in (a) dried milks with different fat contents, (b) different color‐regions of a painting, (c) the thin coating on a compact disc, (d) drug tablets, and (e) porcine brain tissue were rapidly characterized as protonated molecules [M+H]+ or sodiated molecules [M+Na]+ by ELDI‐MS with minimum sample pretreatment. The ionized ions of synthetic polymer and dye standards were detected directly from dried sample solutions using either positive or negative ion mode. Further structural information for the FD&C Red dye was obtained through tandem mass spectrometric (MS/MS) analysis using an ion trap mass analyzer attached to the ELDI source. Copyright © 2007 John Wiley & Sons, Ltd.
Transfer in context: replication and adaptation in knowledge transfer relationships
Authors: Williams Charles
Published: May 2007

This paper explores the role of replication and adaptation in knowledge transfer relationships. I develop a model of knowledge transfer in which firms replicate because knowledge is ambiguous and adapt because knowledge depends on context. In the model, firms replicate more when knowledge is discrete and adapt more when they understand the interactions between different areas of knowledge. Replication and adaptation lead to successful knowledge transfer, which leads to improved performance of the receiving unit. The predictions are tested using a survey of cross‐border knowledge transfer relationships among firms in the telecommunications industry. The results are largely consistent with the model and point to potential areas for future research, such as the drivers of replication, the depreciation rate of knowledge, and the role of understanding in organizational knowledge. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis of needle‐like polyanilines
Authors: Jung Woo‐Hyuk , Lee Young Moo , McCarthy Stephen P.
Published: May 2007

Needle‐like polyanilines were prepared in aqueous media by chemical oxidation. p‐Toluenesulfonic acid (pTSA) was used to protonate aniline (ANi) and readily made the anilinium complex. By slowly adding ammonium peroxydisulfate (APS) at 15°C, polyanilines were prepared in the micelles and grew to be needle‐like aggregates potentially useful as conductive fillers for electromagnetic interference shielding and radar‐absorbing materials. The needle‐like aggregates of protonated polyaniline prepared at 15°C and 0.5 M aniline concentration with 3 h of APS addition time showed conductivity up to 3 S/cm and a maximum aspect ratio of 26 L/D. They were observed by scanning electron microscopy to peel off partially into fibrils after washing. The needle‐like polyaniline‐pTSA complexes prepared with 0.5 M aniline concentration showed good thermal stability up to 200°C. The high conductivity of the needle‐like aggregates was ascribed to their well‐developed crystalline structures, compared with those of spherical particles. J. VINYL ADDIT. TECHNOL., 13:76–86, 2007. © 2007 Society of Plastics Engineers.
Unique atmospheric plasma surface pretreatment approach for improving adhesion
Authors: Wolf Rory A.
Published: May 2007

Three‐dimensional parts and web‐processed products comprised of polyolefins, such as polypropylene, have low levels of polar functional groups on the surface and poor wettability and adhesion properties, thus making it difficult to apply other functional layers such as dyes, inks, adhesives, and coatings. To enhance surface polarity, surface treatments such as flame, corona, or plasma can be applied to improve wettability and adhesion. Plasma can be used specifically as a preparatory treatment for the photografting approach recommended in this paper in order to achieve high stability in treatment and permanent changes to the surface. J. VINYL ADDIT. TECHNOL., 13:87–90, 2007. © 2007 Society of Plastics Engineers.
Crosslinking of rigid poly(vinyl chloride) with epoxysilane
Authors: Li Lanjun , Chen Xian , He Bobing
Published: May 2007

Crosslinking is an effective way to improve the properties of poly(vinyl chloride). A crosslinking agent consisting of R‐glycidoxypropyltrimethoxysilane (KH560) has been used for the first time in order to introduce crosslinking into rigid poly(vinyl chloride). Different thermal stabilizers (organotin, Ca/Zn stearate, and Ba/Zn stearate) as well as sodium bisulfite were tried in order to promote grafting of the epoxy group and enhance the degree of crosslinking. Fourier transform infrared (FTIR) spectra showed that grafting and crosslinking of KH560 with poly(vinyl chloride) could take place, and that a gel content of 40% could be obtained when more than 10 phr of epoxysilane was used with a 2:1 (weight) ratio of BaSt2/ZnSt2 and a 1:1 molar ratio of NaHSO3/KH560, while premature crosslinking was avoided. The Vicat softening temperature of crosslinked PVC could be increased by about 10°C when 5 phr of epoxysilane was added, and thermal degradation could be delayed with increasing gel content. Therefore, epoxysilane‐crosslinked PVC has the potential for extensive applications. J. VINYL ADDIT. TECHNOL., 13:103–109, 2007. © 2007 Society of Plastics Engineers.
Hot pin welding of thin poly(vinyl chloride) sheet
Authors: Van de Ven James D. , Erdman Arthur G.
Published: May 2007

This paper develops a method of welding two thin sheets of poly(vinyl chloride) (PVC) with a heated pin, thus allowing construction of a relationship between the weld temperature and weld strength. Constructing a relationship between weld strength and temperature is necessary for modeling many welding processes, including laser transmission welding. An experimental approach to establishing this relationship is required because of the complex melting behavior of PVC. The designed experimental device uses a single heated pin to weld samples by using varying pressure and temperature for one second dwell time. An electro‐mechanical loadframe pulled the welded samples until joint failure occurred, thereby allowing determination of the weld strength. An experiment varying welding pin temperature and joining pressure found the temperature to be a highly significant determiner of weld strength, while the pressure was found to be not significant. A transient numerical heat transfer model was used to calculate the weld interface temperature for each pin temperature. The relationship established in this paper can be used to predict the weld strength from the temperature output from models of alternative welding methods. J. VINYL ADDIT. TECHNOL., 13:110–115, 2007. © 2007 Society of Plastics Engineers.
Delay from Symptom Onset Increases the Conversion Rate in Laparoscopic Cholecystectomy for Acute Cholecystitis
Authors: Hadad Sirwan M. , Vaidya Jayant S. , Baker Lee , Koh Hoey C. , Heron Timothy P. , Thompson Alastair M.
Published: May 2007

Background

Randomized trials suggest that laparoscopic cholecystectomy should be performed on first admission for acute cholecystitis. However, this is not widely practiced, possibly because of a perceived high conversion rate. We hypothesized that delay from onset of symptoms may increase the conversion rate.

Methods

We performed a retrospective case note review of patients undergoing emergency cholecystectomy in a single institution between January 2002 and December 2005. We analyzed whether delay from onset of symptoms was related to the conversion rate in patients with a histopathological diagnosis of acute cholecystitis.

Results

Of patients who underwent emergency laparoscopic cholecystectomy in our institution, 32.4% (197/608) had acute cholecystitis on histopathology. The conversion rate of those with acute cholecystitis was considerably higher (24.4%) than for those with other pathologies (6.3%). For patients with acute cholecystitis, the conversion rates increased with duration of symptoms: 9.5%, 16.1%, 38.9%, and 38.6% for delays of 0–2 days, 3–4 days, 5–6 days, and > 6 days from symptom onset, respectively (chi‐square for trend = 14.27, DF = 1, p = 0.00016). Most conversions were due to the presence of acute inflammatory adhesions.

Conclusions

Early intervention for acute cholecystitis (preferably within 2 days of onset of symptoms) is most likely to result in successful laparoscopic cholecystectomy; increasing delay is associated with conversion to open surgery.