bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal Shock loading of a surface crack in a hollow sphere
Authors: Grebner H. 
Published: June 2005

AbstractTemperature and stress distributions in a hollow sphere are calculated, caused by a sudden cooling (thermal shock) of the inner surface of a hollow sphere. The thermal stresses are acting as load of surface cracks of approximate semi‐elliptic shape. By means of the weight functions method stress intensity factors are estimated at the deepest point of the cracks using the well‐known Newman‐Raju solution for semi‐elliptical surface cracks in a plate as reference solution.
In vivo detection of iron and neuromelanin by transcranial sonography: A new approach for early detection of substantia nigra damage
Authors: Zecca Luigi , Berg Daniela , Arzberger Thomas , Ruprecht Petra , Rausch Wolf D. , Musicco Massimo , Tampellini Davide , Riederer Peter , Gerlach Manfred , Becker Georg 
Published: June 2005

AbstractEarly diagnosis of Parkinson's disease (PD) in nonsymptomatic patients is a key issue. An increased echogenicity of the substantia nigra (SN) was found previously in Parkinsonian patients and in a low percentage of healthy adults. These nonsymptomatic subjects also showed a reduced 18F‐dopa uptake in striatum, suggesting a preclinical injury of the nigrostriatal system that could later proceed into PD. To investigate the ability of ultrasonography to detect markers of SN degeneration, such as iron deposition and neuromelanin depletion, we scanned postmortem brains from normal subjects at different ages by ultrasound and measured the echogenic area of the SN. The SN was then dissected and used for histological examinations and determination of iron, ferritin, and neuromelanin content. A significant positive correlation was found between the echogenic area of the SN and the concentration of iron, H‐ and L‐ferritins. Multivariate analysis carried out considering the iron content showed a significant negative correlation between echogenicity and neuromelanin content of the SN. In PD, a typical loss of neuromelanin and increase of iron is observed in this brain area. The finding of a positive correlation between iron and ferritin levels and a negative correlation of neuromelanin content with the area of echogenicity at the SN could therefore provide an interesting basis for diagnosis and therapeutic follow‐up studies in PD. © 2005 Movement Disorder Society
Vibration‐induced disruption of retrograde axoplasmic transport in peripheral nerve
Authors: Yan Ji‐Geng , Matloub Hani S. , Sanger James R. , Zhang Lin‐Ling , Riley Danny A. 
Published: June 2005

AbstractHand‐arm vibration syndrome (HAVS) results from excessive exposure to hand‐transmitted vibration. Whether the peripheral nerve damage characteristic of HAVS is a direct result of vibration or is secondary to vascular insufficiency remains unclear. The purpose of this study was to explore the effect of vibration exposure on axoplasmic transport in peripheral nerves and soleus motor neurons. Sciatic nerves and motor neurons from rats following two 5‐h periods of vibration exposure demonstrated disruption in retrograde transport compared to normal. After 10 days of vibration (5 h/day), axoplasmic transport failed to recover within 24–48 h in most rats. This study demonstrates that disrupted axoplasmic transport is an early consequence of short‐term vibration exposure. The effects of vibration on axoplasmic transport also appear to be cumulative. This study provides a new biological way to evaluate measures to prevent early vibration injury. Muscle Nerve, 2005
Application of h‐adaptive FEM and Zarka's approach to analysis of shakedown problems
Authors: Cecot Witold 
Published: June 2005

AbstractThe Zarka shakedown approach and the h‐adaptive finite element method are applied to evaluate residual stresses resulting from arbitrary cyclic loading. Two error indicators are used to refine the mesh: the explicit residual one which controls accuracy of the momentum balance and the interpolation error indicator which controls approximation of the modified back stresses. Validation tests performed for the Zarka method of simplified shakedown analysis suggest that such an approach may be used to obtain a quick estimate of residual states with the error acceptable for engineering purposes. Thus, it has been applied to compute residual stresses arising from service load in railroad rails. Copyright © 2004 John Wiley & Sons, Ltd.
Forced vibrations in the medium frequency range solved by a partition of unity method with local information
Authors: De Bel E. , Villon P. , Bouillard Ph. 
Published: June 2005

AbstractA new approach for the computation of the forced vibrations up to the medium frequency range is formulated for thin plates. It is based on the partition of unity method (PUM), first proposed by Babuška, and used here to solve the elastodynamic problem. The paper focuses on the introduction of local information in the basis of the PUM coming from previous approximations, in order to enhance the accuracy of the solution. The method may be iterative and generates a PUM approximation leading to smaller models compared with the finite element ones required for a same accuracy level. It shows very promising results, in terms of frequency range, accuracy and computational time. Copyright © 2004 John Wiley & Sons, Ltd.
Parameter identification in constitutive models via optimization with a posteriori error control
Authors: Johansson Håkan , Runesson Kenneth 
Published: June 2005

AbstractIn this paper we outline a computational technique for the calibration of macroscopic constitutive laws with automatic error control. In the most general situation the state variables of the constitutive law, as well as the material parameters, are spatially non‐homogeneous. The experimental observations are given in space–time. Based on an appropriate dual problem, we compute a posteriori the discretization error contributions from approximations of the parameter, state and costate fields in space–time for an arbitrarily chosen goal‐oriented error measure of engineering significance. Such a measure can be used in an adaptive strategy (not discussed in this paper) to meet a predefined error tolerance. An important observation is that the Jacobian matrix associated with the resulting Newton method is used (in principle) in solving the dual problem. Rather than treating the Jacobian in a monolithic fashion, we utilize a sequential solution strategy, whereby the FE‐topology of the discretized state problem is used repeatedly. Moreover, the proposed solution strategy lends itself naturally to the computation of first and second order sensitivities, which are obtained with little extra computational effort. Numerical results are given for the prototype model of confined aquifer flow with spatially non‐homogeneous permeability. The efficiency of the optimization strategy and the effectivity of the error computation are assessed. Copyright © 2005 John Wiley & Sons, Ltd.
Validation of the LES approach in Kiva‐3V on a square duct geometry
Authors: Huijnen V. , Somers L. M. T. , Baert R. S. G. , de Goey L. P. H. 
Published: June 2005

AbstractThe LES approach implemented in the Kiva‐3V code is evaluated on the fully developed flow through a rectangular duct of square cross section. The Reynolds number based on the bulk velocity and duct width is 8000. The number of grid nodes is 96000. Three subgrid‐scale models are compared: the Smagorinsky, the WALE and the Vreman model. The results differ mainly in the predicted shear stress levels. The Smagorinsky model shows a large overprediction of the shear at the walls, whereas both the WALE and Vreman models perform better due to a reduced contribution of the subgrid dissipation. In this study the WALE model gives the best results on simulating the secondary flows and turbulence statistics. Copyright © 2005 John Wiley & Sons, Ltd.
Strahlende Kostbarkeiten: Uran als Farbkörper in Gläsern und Glasuren
Authors: Schwankner Robert Josef , Eigenstetter Michael , Laubinger Rudolf , Schmidt Michael 
Published: June 2005

AbstractDas älteste heute bekannte Uranglas stammt aus dem Wandmosaik einer spätrömischen Villa nahe Neapel (79. n. Chr.). Für die moderne Chemie entdeckte Martin Heinrich Klaproth das Uran im Jahr 1789. Er erkannte schnell, dass Oxide und weitere Verbindungen des Urans sich gut zum Färben von Glasuren und Gläsern eignen. Ab Mitte des 19. Jahrhunderts entstanden sehr viele Objekte aus uranhaltigen Gläsern oder mit solchen Glasuren, etwa Geschirr, Ziergläser, Kacheln oder Bijouteriewaren. Manche dieser Objekte werden heute noch hergestellt, viele historische sind noch im Umlauf. Ihre Erforschung und strahlenhygienische Einordnung ist Aufgabe der konservatorischen Radiometrie.
Quételet‐Ringe auf Fenstern: Spielwiese
Authors: Schlichting H. Joachim 
Published: June 2005

AbstractQuételetsche Ringe zeigen sich dem aufmerksamen Beobachter zuweilen an verschmutzten Fensterscheiben, die aus hinreichender Entfernung mit einem Autoscheinwerfer angestrahlt werden. Besonders geeignet scheinen Fensterscheiben zu sein, die durch eine Bedampfung mit einer reflektierenden Schicht ein stärkeres Reflexionsvermögen aufweisen als normale Scheiben. Quételet‐Ringe kommen dadurch zustande, dass sich an Schmutzteilchen gestreute und anschließend an der Rückseite der Scheibe reflektierte Lichtstrahlen mit an der Scheibenvorderseite reflektierten und anschließend an jeweils denselben Teilchen gestreuten Lichtstrahlen überlagern. Das Phänomen lässt sich an einem mit Gips eingestäubten Spiegel im Lichte eines Halogenstrahlers experimentell nachvollziehen.
Der Doppelspaltversuch in moderner Form
Authors: Paulus Gerhard G. 
Published: June 2005

AbstractDer Doppelspaltversuch gilt als eines der zentralen Experimente der Quantenmechanik. Dies gilt insbesondere auch für die 1961 durchgeführte Variante mit Elektronen. Physiker in Europa und den USA haben diesen Versuch nun so abgeändert, dass die Interferenz nicht im Orts‐, sondern im Zeitraum stattfindet.
Photocycloaddition‐induced preparation of nanostructured, cyclic polymers using biscinnamated or biscoumarinated oligo(ethylene glycol)s
Authors: Nakayama Y. , Matsuda T. 
Published: June 2005

AbstractTwo types of photoreactive water‐soluble oligo(ethylene glycol)s (OEGs; Mn = ca. 6500) were prepared by derivatization of OEG with photodimerizable groups such as cinnamates or coumarinates at both ends. Upon UV light irradiation of biscinnamated OEG in an aqueous solution, almost all trans‐cinnamate groups were isomerized to cis form in preference to dimerization even in an associated state at high concentrations of cinnamate groups, whereas dimerization via intermolecular photocycloaddition was the dominant process in methanol solution and in the film state. Coumarinate groups attached to OEG were photodimerized by UV irradiation, and this process was enhanced in an aqueous solution and in film cast from a polar solvent by hydrophobic association between coumarinate groups, resulting in the production of macromolecules. Kinetic analysis revealed that for low‐concentration aqueous solutions or a film cast from a nonpolar solvent, predominantly circular trimers to tetramers were produced on average, whereas from high‐concentration aqueous solutions or film cast from a polar solvent, mostly cyclic heptamers were produced. These results suggest that the molecular design of nanostructured, cyclic polymers of various sizes is possible by changing the concentration of aqueous solutions and cast solvents in this photoaddition system. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3324–3336, 2005
Preparation and phase behavior of side‐chain cholesteric liquid‐crystalline elastomers
Authors: Hu Jian‐She , Zhang Bao‐Yan , Zhou Ai‐Juan , Dong Yan‐Li , Zhao Zhan‐Xiang 
Published: June 2005

AbstractA series of new side‐chain cholesteric elastomers derived from cholesteryl 4‐(10‐undecylen‐1‐yloxy)‐4′‐ethoxybenzoate and phenyl 4,4′‐bis(10‐undecylen‐1‐yloxybenzoyloxy‐p‐ethoxybenzoate) was synthesized. The chemical structures of the monomers were confirmed by elemental analyses, Fourier transform infrared, and 1H NMR and 13C NMR spectra. The mesomorphic properties of elastomers were investigated with differential scanning calorimetry, thermogravimetric analysis, polarizing optical microscopy, and X‐ray diffraction measurements. The influence of the content of the crosslinking unit on the phase behavior of the elastomers was examined. Monomer M1 showed a cholesteric phase, and M2 displayed smectic and nematic phases. The elastomers containing <15 mol % of the crosslinking units revealed reversible mesomorphic phase transition, wide mesophase temperature ranges, and high thermal stability. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3315–3323, 2005
Influence of the cocatalyst structure on the statistical copolymerization of methyl methacrylate with bulky methacrylates using the zirconocene complex Cp2ZrMe2
Authors: Kostakis Konstantinos , Mourmouris Stylianos , Kotakis Konstantinos , Nikogeorgos Nikolaos , Pitsikalis Marinos , Hadjichristidis Nikos 
Published: June 2005

AbstractStatistical copolymers of methyl methacrylate with cyclohexyl and trimethylsilyloxy ethyl methacrylate were synthesized with two different catalytic systems based on the zirconocene complex Cp2ZrMe2. The reactivity ratios of methyl methacrylate and these methacrylates were calculated with the Finemann–Ross, inverted Finemann–Ross, and Kelen–Tüdos graphical methods. The structural parameters of these copolymers were estimated from the calculation of the dyad monomer sequence fractions. Two different borate cocatalysts were employed, and their effect on the copolymerization process is discussed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3305–3314, 2005
Polymerization of acrylates and bulky methacrylates with the use of zirconocene precursors: Block copolymers with methyl methacrylate
Authors: Kostakis Konstantinos , Mourmouris Stylianos , Pitsikalis Marinos , Hadjichristidis Nikos 
Published: June 2005

AbstractThe polymerization behavior of cyclohexyl methacrylate and trimethylsilyloxyethyl methacrylate with the catalytic system Cp2ZrMe2/B(C6F5)3/ZnEt2 was examined. Block copolymers of these bulky methacrylates with methyl methacrylate (MMA), having high molecular weights and relatively narrow molecular weight distributions, were prepared. n‐Butyl acrylate and tert‐butyl acrylate were polymerized with various catalytic systems based on zirconocene complexes. These polymerizations seemed to proceed to a nonquantitative yield, producing polymers with high molecular weights and relatively low polydispersities. This behavior indicated the presence of termination reactions in the initiation step, which appeared to be faster than the propagation step. Block copolymers of these acrylates with MMA were synthesized with the catalytic system rac‐Et(Ind)2ZrMe2/[B(C6F5)4]−[Me2NHPh]+/ZnEt2, starting from the polymerization of MMA. The block copolymers produced were well defined in most cases, as indicated by size exclusion chromatography, NMR, and differential scanning calorimetry measurements. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3337–3348, 2005
Electrical Conduction Mechanisms of Nitrogenated Amorphous Carbon Films Deposited by High‐Density Plasma Chemical Vapor Deposition
Authors: Guerino Marciel , Mousinho Ana P. , Massi Marcos , Mansano Ronaldo D. 
Published: June 2005

AbstractSummary: In this work, we study the electrical conduction mechanisms of nitrogenated amorphous carbon (a‐C:H:N) films, which were deposited by a high‐density plasma chemical vapor deposition (HDP‐CVD) technique. The plasma was inductively coupled by an external planar coil. Mixtures of methane and nitrogen at different concentrations were used in the depositions. The working pressure process was 15 mTorr and the RF power was 250 W. An analysis focused on the influence of the precursor gases and plasma parameters on the conduction mechanisms of the a‐C:H:N films is reported. Current‐voltage (I‐V) curves were used to study the conduction mechanisms of the a‐C:H:N films. As a result of these studies we observed that the main electrical conduction mechanism found in the I‐V characteristics of our a‐C:H:N films was the Poole‐Frenkel emission. I‐V curves were also obtained in the range of 0–100 V and they were used to determine the electrical resistivity of the films.Current‐voltage characteristics of the a‐C:H:N films deposited with various N2 content in the discharge.magnified imageCurrent‐voltage characteristics of the a‐C:H:N films deposited with various N2 content in the discharge.
Characterizing the Structure of Abrasive Fineparticles
Authors: Kaye Brian H. , Clark Garry G. , Liu Ying 
Published: June 2005

AbstractA new computer‐aided image analysis procedure for characterizing the number and sharpness of potential cutting facets on the profiles of the image of an abrasive fineparticle is described. In the method, the digitized profile is explored by a running chord generating procedure which generates what is described as the facet signature of the profile. This signature can be processed at different threshold levels to recognize facets of the profile having different levels of sharpness as defined by the acute angle of the facet. Several different ways in which data from the procedure could be used to describe a population of polishing powder fineparticles are outlined. The potential use of the new descriptive characterization procedures for following the physical changes in the powder corresponding to the degeneration in performance of a polishing powder during use is outlined. The possible use of the new methodology to describe the health hazards of angular shaped dust fineparticles and flake type fillers (such as mica) in composite material technology is outlined.
Data Scatter in Richardson Plots
Authors: Clark Nigel N. , Maeder Anthony J. , Reilly Stephanie 
Published: June 2005

AbstractTwo dimensional images are often used as a basic for calculating shape descriptors of particles. An edge roughness descriptor, the fractal dimension, can be found from a Richardson plot of measured perimeter versus the measuring step length. Data Scatter on these plots is shown to be related to the incipient formation of polygonal harmonics, which are regular polygons formed during a structured walk around the image edge. This relationship was verified using both computer generated fractal images and real particle outlines.
Characterization of the Structure of Agglomerate Particles
Authors: Rogak Steven N. , Flagan Richard C. 
Published: June 2005

AbstractAgglomerates of uniformly sized primary spheres are found in many aerosol and colloidal systems. Such particles have been described as fractal although they possess selfsimilarity over only a narrow range of length scales. Previous work suggests that, for such objects, ideal fractal scaling laws may require substantial corrections. The problem is particularly acute for measurements of particle structure from 2d images. The relation between the structure of an agglomerate and the characteristics of its projection is investigated using simple analytical models and clusters generated by a modified cluster cluster aggregation simulation. The morphology of the simulated clusters is varied by changing the ratio of masses of the colliding clusters. The fractal dimensions Df3 of the simulated clusters were typically 10–20% higher than those measured for the projections, Df2, even though Df3 > 2. This difference decreases as the cluster size increases. It was found that the fraction of primary particles visible in the 2d image is more sensitive to cluster size than to fractal dimension for clusters with less than several thousand primary particles.
The Aggregation Probability in Random Coagulation and Breakup Processes
Authors: Cohen Ruben D. 
Published: June 2005

AbstractA single parameter, denoted as the "aggregation probability", is introduced to represent the average potential of clustering in a suspension in which the aggregates are undergoing random and simultaneous coagulation and breakup by means of mechanical stirring. The parameter may be useful for obtaining quick estimates of the equilibrium cluster size distributions in such systems.
Transport and Deposition of Wear Particles in Computer Disk Drives
Authors: Tsai Chuen‐Jinn , Pui David Y. H. , Liu Benjamin Y. H. 
Published: June 2005

AbstractTo understand the roles that wear particles play in disk crashes, analytical and numerical approaches have been used to study three dimensional fluid flow and wear particle transport and deposition in computer disk drives. The study shows that wear particles are flying very close to the disk surface. They can deposit on the disk surface and cause damage to disk drives. Cooling air flow through the disk hub of corotating disks has been found to play important roles in removing wear particles from disk drives. Parametric study has shown that the optimum cooling air flow rate is 12 slpm for 8″ disk with the Reynolds number of 150,000.
Operation Characteristics of Vibrating‐Orifice Generators: The coherence length
Authors: Anders Klaus , Roth Norbert , Frohn Arnold 
Published: June 2005

AbstractThe use of monosized droplet streams for the calibration and testing of optical particle sizing methods and their application to the study of basic phenomena in two‐phase systems are discussed. Owing to their coherent structure–all the droplets have the same size and spacing–such droplet streams are very useful tools for these applications. The droplets streams have been produced with a vibrating‐orifice generator. Limitations and problems that occur during the operation of these generators are described. Special emphasis is laid on the problem of the loss of coherence with increasing distance from the exit of the generator, which sometimes restricts the application of the generator for certain purposes.
Evaluation of the Dual‐Cylindrical Wave Laser Technique for sizing of liquid droplets
Authors: Naqwi Amir A. , Liu Xiao‐Z. , Durst Franz 
Published: June 2005

AbstractThe newly developed dual‐cylindrical wave laser system is an alternative to the phase Doppler technique. It requires only frequency measurements for particle sizing and velocimetry, and hence prevents the difficulties associated with the phase measurements. This technique was evaluated experimentally using monosize liquid droplets of water and diethyl phthalate. The experimental results are compared with the theoretical predictions of the system response, based on geometrical optics and the electromagnetic theory of light, under certain simplifying assumptions. Although the measurements generally agree with the theory, some minor oscillations in the measured response are only roughly represented by the theory. Also, the experimental data indicate a large deviation from the theory if the particle is within a distance of three diameters from the origin of the cylindrical waves, hence defining the boundary of the region in which the theory is applicable. This work indicates that a properly laid out dual‐cylindrical wave laser system can be employed for sizing of small droplets in liquid sprays.
Monte Carlo Simulation of Multiple Scattering in arbitrary 3‐D geometry
Authors: Briton Jean‐Philippe , Maheu Bruno , Gréhan Gérard , Gouesbet Gérard 
Published: June 2005

AbstractMUSCAT is a Monte Carlo code for numerical simulation of Multiple Scattering. Only the general restrictive assumptions of the steady‐state, scalar radiative transfer equation are required, hence the MUSCAT code can deal with a broad field of applications. The algorithm follows the physical phenomena as closely as possible and realistic 3‐D problems can be handled without geometric simplifications. Special care has been devoted to the analysis and validation of the pseudo‐random generator subroutine. Global validations of the code in 1‐D and 2‐D geometries have been successfully carried out. An example of application is reported concerning 3‐D studies of visibility in foggy weather.