bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bichromatic spectroscopy of coherent population trapping resonances with phase‐locked fields
Authors: Akimov A. V. , Matveev A. N. , Sokolov A. V. , Sorokin V. N. , Kanorsky S. I. , Kolachevsky N. N. 
Published: February 2005

AbstractWe propose a new approach to the study of coherent population trapping (CPT) resonances using a phase‐coherent bichromatic light source based on a mode‐locked femtosecond laser as an intermediate frequency coupler. The source consists of two diode lasers tuned to the rubidium D2 line (780 nm) which are phase locked to different longitudinal modes of a femtosecond laser MIRA‐900F with 75 MHz repetition rate. Using this bichromatic source with a stable differential frequency, we excited and investigated the CPT resonances in the three‐level system 5s S1/2 (F = 2) ↔ 5s P3/2 (F = 2) ↔ 5s S1/2 (F = 3) of the 85Rb atom. Potentially, this method opens up the possibility of coherently exciting Raman transitions with differential frequencies up to hundreds of terahertz. Copyright © 2005 John Wiley & Sons, Ltd.
Influence of the dehydration process on active compounds of okara during its fractionation
Authors: Surel Olivier , Couplet Blandine 
Published: February 2005

AbstractOkara (residue of the soymilk manufacture) is rich in proteins, fibres and lipids. It also contains isoflavones that possess health‐promoting properties. A new method has been developed for the valorization of fibres from okara by hydrolysis of insoluble proteins with a protease and removal of the oil. Three different processes were investigated: the first one involved delipidation and drying prior to proteolysis and led to the highest content of fibre (80%) in the final product. The second used proteolysis on crude okara followed by solvent delipidation–dehydration and gave an intermediate content of fibre (75%). The last process was totally enzymatic (proteolysis and lipolysis) and gave the lowest content of fibre in the final product (50%). Fibre water‐holding capacity was correlated to the total dietary fibre content of each sample. It was preferable to use crude okara for hydrolysis, since oven‐drying during the process decreased the water‐holding capacity and modified the isoflavone profile of okara. Copyright © 2005 Society of Chemical Industry
Proximate composition and free radical scavenging activity of edible fruits from the Argentinian Yungas
Authors: Schmeda‐Hirschmann Guillermo , Feresin Gabriela , Tapia Alejandro , Hilgert Norma , Theoduloz Cristina 
Published: February 2005

AbstractThe proximate composition and free radical scavenging effect of native food plants gathered in the Argentinian Yungas have been assessed. Some 25 samples were collected for proximate analysis and free radical scavenging effect of their MeOH‐soluble extracts. Total acidity, phenolics and solid content of 16 preserves prepared from native fruits have been determined. The samples belong to 13 different species corresponding to eight plant families, mainly Myrtaceae, Solanaceae and Ulmaceae. The highest organic acid contents (as citric acid) were found in the preserves of Psidium guineense and Cyphomandra betaceae with the lowest in Sideroxylon obtusifolium and Myrciantes pungens. Total phenolics in the preserves ranged from 0.34 g kg−1 DM in Rhipsalis flocosa to 7.30 g kg−1 DM in Celtis iguanae. The MeOH‐solubles of the fruits/petioles as well as the preserves were assessed for inhibition of the enzyme xanthine oxidase (XO), decoloration of the free radical 2,2‐diphenyl‐1‐picryl‐hydrazyl (DPPH) and scavenging of the superoxide anion. The highest effect of the solubles towards the DPPH assay was observed for M pungens and Rubus imperialis before processing. None of the samples was effective as a XO inhibitor or superoxide anion scavenger. The best protein sources in our study were the fruits of Carica quercifolia, Celtis iguanae and Sambucus nigra. Copyright © 2005 Society of Chemical Industry
An efficient algorithm for modelling progressive damage accumulation in disordered materials
Authors: Nukala Phani Kumar V. V. , Šimunović Srđan , Guddati Murthy N. 
Published: February 2005

AbstractThis paper presents an efficient algorithm for the simulation of progressive fracture in disordered quasi‐brittle materials using discrete lattice networks. The main computational bottleneck involved in modelling the fracture simulations using large discrete lattice networks stems from the fact that a new large set of linear equations needs to be solved every time a lattice bond is broken. Using the present algorithm, the computational complexity of solving the new set of linear equations after breaking a bond reduces to a simple triangular solves (forward elimination and backward substitution) using the already Cholesky factored matrix. This algorithm using the direct sparse solver is faster than the Fourier accelerated iterative solvers such as the preconditioned conjugate gradient (PCG) solvers, and eliminates the critical slowing down associated with the iterative solvers that is especially severe close to the percolation critical points. Numerical results using random resistor networks for modelling the fracture and damage evolution in disordered materials substantiate the efficiency of the present algorithm. In particular, the proposed algorithm is especially advantageous for fracture simulations wherein ensemble averaging of numerical results is necessary to obtain a realistic lattice system response. Copyright © 2005 John Wiley & Sons, Ltd.
A new hybrid method for solving linear–non‐linear systems of equations
Authors: Lukasiewicz S. A. , Hojjati M. H. 
Published: February 2005

AbstractThis paper presents a new method for solving any combination of linear–non‐linear equations. The method is based on the separation of linear equations in terms of some selected variables from the non‐linear ones. The linear group is solved by means of any method suitable for the linear system. This operation needs no iteration. The non‐linear group, however, is solved by an iteration technique based on a new formula using the Taylor series expansion. The method has been described and demonstrated in several examples of analytical systems with very good results. The new method needs the initial approximations for non‐linear variables only. This requires far less computation than the Newton–Raphson method. The method also has a very good convergence rate. The proposed method is most beneficial for engineering systems that very often involve a large number of linear equations with limited number of non‐linear equations. Copyright © 2005 John Wiley & Sons, Ltd.
Treatment of discontinuity in the reproducing kernel element method
Authors: Lu Hongsheng , Wan Kim Do , Kam Liu Wing 
Published: February 2005

AbstractA discontinuous reproducing kernel element approximation is proposed in the case where weak discontinuity exists over an interface in the physical domain. The proposed method can effectively take care of the discontinuity of the derivative by truncating the window function and global partition polynomials. This new approximation keeps the advantage of both finite element methods and meshfree methods as in the reproducing kernel element method. The approximation has the interpolation property if the support of the window function is contained in the union of the elements associated with the corresponding node; therefore, the continuity of the primitive variables at nodes on the interface is ensured. Furthermore, it is smooth on each subregion (or each material) separated by the interface. The major advantage of the method is its simplicity in implementation and it is computationally efficient compared to other methods treating discontinuity. The convergence of the numerical solution is validated through calculations of some material discontinuity problems. Copyright © 2005 John Wiley & Sons, Ltd.
A Crank‐Nicolson Petrov‐Galerkin method with quadrature for semi‐linear parabolic problems
Authors: Bialecki B. , Ganesh M. , Mustapha K. 
Published: February 2005

AbstractWe propose and analyze an application of a fully discrete C2 spline quadrature Petrov‐Galerkin method for spatial discretization of semi‐linear parabolic initial‐boundary value problems on rectangular domains. We prove second order in time and optimal order H1 norm convergence in space for the extrapolated Crank‐Nicolson quadrature Petrov‐Galerkin scheme. We demonstrate numerically both L2 and H1 norm optimal order convergence of the scheme even if the nonlinear source term is not smooth. © 2005 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2005.
The pseudo‐elastic response of rubberlike solids
Authors: Dorfmann A. 
Published: February 2005

AbstractIn this paper we focus on the mechanical behaviour of filled natural rubber. Filled elastomers under cyclic loading show noticeable differences between the mechanical response under loading and unloading during the first cycles in oscillation tests. We examine the change in material response associated with the Mullins effect and with cavitation, the latter arising from hydrostatic tensile stresses of sufficient magnitude. Then, we focus on constitutive equations using the theory of pseudoelasticity. Specifically, the strain‐energy function depends on a scalar parameter, which provides a means for modifying the form, thereby reflecting stress softening observed during unloading. The dissipation of energy is also accounted for by the use of a dissipation function, which evolves with the deformation history. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Tests for the validation of numerical models for cracking of plain concrete
Authors: Feist Christian , Hofstetter Günter 
Published: February 2005

AbstractThe paper deals with experiments on single edge notched beams, subjected to 2D and 3D stress states, for the validation of material models for cracking of plain concrete. Both, the test setup and the test results, mainly consisting of load – displacement curves and crack paths and crack surfaces, are described briefly. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Messsystem zur Bestimmung der Kavitationsempfindlichkeit von Wasser
Authors: Heller W. , Kempe T. 
Published: February 2005

AbstractDie Bedingungen für das Auftreten von Kavitation, d. h. das lokale Verdampfen der Flüssigkeit unter statischer oder dynamischer Zugbeanspruchung, sind eng verknüpft mit dem Zustand der Flüssigkeit hinsichtlich seiner “Zerreissfestigkeit”. Obwohl seit vielen Jahren der dominante Einfluss der Wasserqualität auf den Kavitationsbeginn bekannt ist, wird nach wie vor international dieser Parameter nicht gemessen. Sowohl bei der ASME/JASME Konferenzen in San Francisco 1999 [1] und Honolulu 2003 [2], als auch beim Fourth International Symposium on Cavitation in Pasadena 2001 [3] wurde deutlich, dass international vergleichbare Versuchsbedingungen bezüglich der Berücksichtigung der Wasserqualität geschaffen werden müssen. Eine relativ einfache Methode zur permanenten Messung der Zugspannung bzw. Kavitationsempfindlichkeit an Kavitationskanälen wurde in den letzten Monaten am ISM der TU Dresden konzipiert und gebaut. Diese Zugspannungsmesseinrichtung stellt nicht nur eine praktikable und kostengünstige Möglichkeit zur Messung dar, sondern sie kann mit relativ geringem Aufwand in alle bestehenden Kavitationskanäle eingebaut werden. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Identification of the Material Parameters of a Micropolar Model for Granular Materials
Authors: Scholz Bernd , Ehlers Wolfgang 
Published: February 2005

AbstractGranular frictional materials show a complex stress‐strain behaviour depending on the stress state and the load history. Furthermore, biaxial experiments exhibit the occurrence of shear band phenomena as the result of the localization of plastic strains. It is well known that the onset of shear bands is associated with microrotations of the granular microstructure, which has a significant influence on the macroscopic behaviour. Consequently, the macroscopic material must result in a micropolar model, which incorporates rotational degrees of freedom. After the formulation of the constitutive equations and the numerical implementation, it is necessary to determine all required material parameters. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Betrachtungen über zweieinhalbdimensionale Strömungen zäher Flüssigkeiten mit Gedächtnis
Authors: Böhme G. , Pokriefke G. 
Published: February 2005

AbstractBei der Durchströmung eines Kanals konstanten Querschnitts beliebiger Form stellt sich unter Wirkung eines axialen Druckgradienten und unter der Schleppwirkung bewegter Kanalwände eine räumliche Strömung mit kartesischen Geschwindigkeitskomponenten der Form u(x; y), v(x; y) und w(x; y) ein. Solche zweieinhalbdimensionalen Strömungsfelder besitzen nicht nur bei newtonschen Flüssigkeiten einige bemerkenswerte Eigenschaften, sondern unter gewissen Voraussetzungen auch bei Flüssigkeiten mit Gedächtnis. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical Solution of Some Cardiovascular Problem
Authors: Prokop V. , Kozel K. , Keslerová R. 
Published: February 2005

AbstractThis paper deals with problem of numerical solution of flows through vessel with bypass. One could use model of Navier‐Stokes equations and find solution by using multistage Runge‐Kutta method together with time dependent artificial compressibility method. Some results of numerical solution of cardiovascular problems are presented: stationary and unstationary 2D flows in a vessel and a bypass. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preparation and characterization of polysiloxane–polyacrylates composite latices and their film properties
Authors: Zou Mingxuan , Huang Fangzhi , Nie Jun , Zhang Zhicheng , Ge Xuewu 
Published: February 2005

AbstractGamma‐ray induced seeded emulsion polymerization of methyl methacrylate and butyl acrylate was carried out in the presence of a polymerizable polysiloxane seed latex, obtained by ring‐opening copolymerization of octamethyl cyclotetrasiloxane (D4) and tetramethyl tetravinyl cyclotetrasiloxane (VD4), catalyzed by dodecylbenzene sulfonic acid (DBSA). A series of polysiloxane seed latices with different molecular weights, vinyl contents and particle sizes was used. The conversion–time curve showed that the polymerization rate was accelerated significantly by the seed latex. The obtained composite latices also showed good storage stability, mechanical stability and high electrolyte resistance ability. By using transmission electron microscopy (TEM), the morphology of the composite latex particles was found to display a quite uniform fine structure. The graft polymerization reactions between the polymerizable polysiloxane and the acrylates were confirmed by Fourier‐transform infrared spectroscopy (FT‐IR) and the graft efficiencies were also studied. The influence of seed content, molecular weight, vinyl content of the polysiloxane and seed latex particles size on the mechanical performance, water absorption ratio, surface properties and transparency of the latex films was also investigated. It was found that the seed content and particles size greatly affect the mechanical performance, water absorption ratio and transparency of the latex films. Copyright © 2005 Society of Chemical Industry
Surfactant concentration effects on amorphous PETG–montmorillonite layered silicate (MLS) nanocomposite films
Authors: Ranade Ajit , D'Souza Nandika , Thellen Christopher , Ratto Jo Ann 
Published: February 2005

AbstractImprovements in the dispersion of montmorillonite layered silicates (MLS) have centered on appropriate surfactant treatment of the MLS, to ensure chemical interaction with the polymer material. Here, polyethylene terephthalate glycol (PETG) nanocomposites made with two MLS cation exchanged with dimethyl dihydrogenated tallow quaternary ammonium at two concentrations, 95 (MLS‐95) and 125 meq (100 g)−1 (MLS‐125), were investigated. The host MLS had a cation exchange capacity (CEC) around 92 meq (100 g)−1. The effect of exchanging past the CEC was studied with respect to the dispersion, glass transition and mechanical properties. Films were extruded on a single‐screw extruder with a film die attached. X‐ray diffraction (XRD) and optical transmission measurements indicated that increasing surfactant concentration changed the dispersion from intercalated to immiscible. The differences in the dispersion were related to the inherent degradation temperature of the MLS treated with the different surfactant concentrations, relative to the processing temperature. The over‐exchanged MLS (MLS‐125) suffered more surfactant degradation leading to an immiscible dispersion and narrower XRD peaks reflected a higher degree of ordering. In contrast, the XRD peaks of the MLS‐95 nanocomposites had increased breadth indicating decreased ordering. MLS orientation, however, did not influence birefringence measured by polarized Fourier‐transform infrared spectroscopy (FTIR). All nanocomposites showed no significant changes in the glass transition temperatures. Copyright © 2005 Society of Chemical Industry
Synergistic effect of nickel formate on the thermal and flame‐retardant properties of polypropylene
Authors: Chen Xuecheng , Ding Yaping , Tang Tao 
Published: February 2005

AbstractNickel formate was used as a catalyst to improve the flame‐retardancy of intumescent systems based on ammonium polyphosphate (APP) and pentaerythritol (petol) in polypropylene (PP). Limited oxygen index (LOI), X‐ray diffraction (XRD) and thermogravimetric analysis (TGA) were used to characterize the fire‐retardancy and thermal stability of the PP system and the microstructure of the burned residue. The catalytic effect was shown in an increase in LOI, and a change in the residue microstructure and the thermal stability of the PP system. LOI increased with the concentration of the catalyst in the range 0.1–5 wt% of the composition until a maximum was reached. At higher concentration of the catalyst a decrease in the LOI was observed. Copyright © 2005 Society of Chemical Industry
Synthesis of polypropylene‐graft‐maleic anhydride compatibilizer and evaluation of nylon 6/polypropylene blend properties
Authors: Abacha N , Fellahi S 
Published: February 2005

AbstractPolymer blends based on polyolefins are of a great interest owing to their broad spectrum of properties and practical applications. However, because of poor compatibilities of components, most of these systems generally exhibit high interfacial tension, a low degree of dispersion and poor mechanical properties. It is generally accepted that polypropylene (PP) and nylon 6 (N6) are not compatible and that their blending results in poor materials. The compatibility can be improved by the addition of a compatibilizer, and in this study PP was functionalized by maleic anhydride (MAH) in the presence of an optimized amount of dicumyl peroxide (DCP). The reaction was carried out in the molten state using an internal mixer. Then, once the compatibilizer polypropylene‐graft‐maleic anhydride (PP‐g‐MAH) was prepared, it was added at various concentrations (2.5–10 wt%) to 30/70 glass fibre reinforced N6 (GFRN6) PP, and the mechanical properties were evaluated. It was found that the incorporation of the compatibilizer enhanced the tensile properties (tensile strength and modulus) as well as the Izod impact properties of the notched samples. This was attributed to better interfacial adhesion as evidenced by scanning electron microscopy (SEM). The optimum in these properties was achieved at a critical PP‐g‐MAH concentration. Copyright © 2005 Society of Chemical Industry
Catalysis of aminolysis of p‐nitrophenyl acetate by 2‐pyridones
Authors: Fischer Christian B. , Steininger Harald , Stephenson David S. , Zipse Hendrik 
Published: February 2005

AbstractThe influence of a series of alkyl‐substituted 3‐cyano‐2‐pyridones on the kinetics of the reaction of p‐nitrophenyl acetate (10) with n‐butylamine (9) was studied. The reactions were monitored under pseudo‐first‐order conditions using an excess of n‐butylamine by 1H NMR spectroscopy at 23°C in CDCl3. A non‐linear dependence of the observed rate constants kobs on the pyridone concentration was observed in all cases. The results were analysed using two different kinetic models. The first model is based on the amine‐catalysed background reaction in combination with a pyridone‐catalysed process, whose efficiency is reduced through dimerization of the pyridone catalyst to an inactive dimer. The second model also involves the amine‐catalysed background process, now in combination with a catalysed process proceeding through pre‐equilibrium complexation of the substrate with a 1:1 amine–pyridone complex and a second (rate‐determining) step involving C—N bond formation. In addition to these kinetic studies, the aggregation behaviour of pyridones 2 and 3 was also studied in pure deuteriochloroform solutions and mixtures of n‐butylamine and deuteriochloroform. While substantial aggregation to dimers occurs for both pyridones in deuteriochloroform, no such dimerization appears to occur in deuteriochloroform solutions containing 250 × 10−3 mol l−1 n‐butylamine. This finding strongly supports kinetic model 2 as the more realistic choice. Copyright © 2005 John Wiley & Sons, Ltd.
Concentration effects in the cationic ring‐opening polymerization of 2‐ethyl‐2‐oxazoline in N,N‐dimethylacetamide
Authors: Hoogenboom Richard , Paulus Renzo M. , Fijten Martin W. M. , Schubert Ulrich S. 
Published: February 2005

AbstractThe monomer concentration for the cationic ring‐opening polymerization of 2‐ethyl‐2‐oxazoline in N,N‐dimethylacetamide was optimized utilizing high‐throughput experimentation methods. Detailed 1H‐NMR spectroscopic investigations were performed to understand the mechanistic aspects of the observed concentration effects. Finally, the improved polymerization concentration was applied for the synthesis of higher molecular weight (> 10,000 Da) poly(2‐ethyl‐2‐oxazoline)s. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1487–1497, 2005
Synthesis and optical and electrochemical properties of thermotropic, liquid‐crystalline, semirigid copolyesters based on 2,5‐diphenyl‐1,3,4‐thiadiazole units
Authors: Sato Moriyuki , Tada Yuji , Nakashima Shinji , Ishikura Ken‐ichi , Handa Makoto , Kasuga Kuninobu 
Published: February 2005

AbstractNovel thermotropic liquid‐crystalline (LC) copolyesters were prepared with three disubstituted (4,4′‐, 3,4′‐, and 3,3′‐) dioxydiundecanol derivatives of terphenyl analogues of 1,3,4‐thiadiazole [2,5‐diphenyl‐1,3,4‐thiadiazole (DPTD)], and their optical and electrochemical properties were examined. Their structures were characterized with Fourier transform infrared, 1H NMR spectroscopy, and elemental analyses. The thermal and mesomorphic properties of the copolyesters were investigated with differential scanning calorimetry measurements, polarized microscopy observations, and X‐ray analyses; the data suggested that these copolymers formed LC smectic or nematic phases. The mesomorphic tendency decreased in the following order: 4,4′‐DPTD and 3,4′‐DPTD copolyesters > 4,4′‐DPTD and 3,3′‐DPTD copolyesters > 3,4′‐DPTD and 3,3′‐DPTD copolyesters. Solution and solid‐state ultraviolet–visible (UV–vis) and photoluminescence spectra indicated that the copolyesters displayed maximum absorbances and blue emissions according to the DPTD unit; the peak maxima of absorption and emission spectra of the copolyesters shifted to lower wavelengths in the aforementioned order for the LC properties. Cyclic voltammetry measurements indicated that the electrochemical band gaps of the polyesters estimated from the onset of reduction and oxidation processes were almost the same as the optical band gaps determined from the solid‐state UV–vis spectral data. The DPTD unit enhanced the hole‐injection barrier and improved the charge‐injection balance in these polyesters. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1511–1525, 2005