bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stochastic Particle Method for Nonlinear Hyperbolic Problems
Authors: Tyagi Manav , Jenny Patrick , Lunati Ivan , Tchelepi Hamdi 
Published: January 2007

AbstractIn this paper, we present a new method based on stochastic particles, which allows us to compute solutions of a system of nonlinear transport equations arising in the modeling of immiscible displacement in porous pedia. In this approach, we use different particles for different phases and move them according to the stochastic rules for which the probability density function depends on the spatial distribution of the particles. Our motivation for such a method is a Lagrangian modeling framework in which one can describe certain physical phenomena more naturally than in an Eulerian framework. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Generalized Intervals and the Dependency Problem
Authors: Krämer Walter 
Published: January 2007

AbstractComputing enclosures of the range of functions using interval arithmetic often leads to overestimations due to variables (parameters) appearing more than once within the expression to be evaluated (dependency problem). An experimental implementation of a generalized interval arithmetic which has been proposed by Hansen [2] in 1975 is now available [1, 3]. In many cases generalized intervals are well suited to reduce the dependency problem and/or the so called wrapping effect. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Towards an Axiomatization of Interval Arithmetic
Authors: Markov Svetoslav 
Published: January 2007

AbstractIn this paper intervals are viewed as approximate real numbers. A revised formula for interval multiplication of generalized intervals is given. This formula will be useful for further axiomatization of interval arithmetic and relevant implementations within computer algebra systems. Relations between multiplication of numbers and multiplication of errors are discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimal Design of 2 DOF Parallel Kinematics Machines
Authors: Stan Sergiu‐Dan , Maties Vistrian , Balan Radu 
Published: January 2007

AbstractThe aim of this paper is to show the usefulness of the multicriteria approach to optimize the Parallel Kinematic Machines (PKM). Variations of the kinematic performances index remain not constant throughout workspace. Aiming to deal at the same time with multiple criteria in optimal design of PKM, we have developed a Multi‐Objective Genetic Algorithm (MOGA) using concepts of Pareto optimality and niching techniques. The obtained results have shown that the use of MOGA in such kind of optimization problem enhances the quality of the optimization outcome, providing a better and more realistic support for the decision maker. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polynomial representations from abstract perturbed Krylov methods
Authors: Zemke Jens‐Peter M. 
Published: January 2007

AbstractWe present the framework of “abstract perturbed Krylov methods”, a new, unified point of view on different types of Krylov subspace methods. We give a brief informal sketch of polynomial representations of QOR approximations to solutions of linear systems and eigenvectors. The results are applicable to exact arithmetic, finite precision computations including semiduality approaches, and inexact methods. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Difference schemes for a general parabolic problem with interface
Authors: Jovanović Boško S. , Vulkov Lubin G. 
Published: January 2007

AbstractStability and convergence of finite difference schemes approximating a general parabolic partial differential equation with interface are examined. Convergence rate estimates compatible with the smoothness of the input data are obtained. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling and numerical analysis of the thread rolling process
Authors: Kukielka Krzysztof , Kukielka Leon 
Published: January 2007

AbstractThe paper presents the physical and mathematical models of deformations (displacements and strains) and the stress in the cold process of the thread rolling. The process is considered as a geometrical and physical nonlinear, initial as well as a boundary value problem. The phenomena of a typical incremental step were described using a step‐by‐step incremental procedure, in the updated Lagrangian formulation. The state of strains was described by Green‐Lagrange's tensor, while the state of stress was described by the second symmetrical Pioli‐Kirchhoff's tensor. The object was treated as an elastic (in the reversible zone) and visco‐plastic body (in the non‐reversible zone) with mixed hardening. The variational equation of the motion in three dimensions for this case was proposed. Then, the finite elements methods (FEM) and dynamic explicit method (DEM) were used to obtain the solution. In a numerical analysis, boundary condition for a displacement increment, was determined in the model investigation. The results of a numerical analysis were compared and verified in an experimental investigation. Examples of calculations of the influence of a friction coefficient on the state of the deformation and stress, and an example application for this method of thread rolling were presented. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical Computation of Heat and Mass Transfer in Fluidized Beds with Liquid Injection
Authors: Nagaiah Chamakuri , Warnecke Gerald , Heinrich Stefan , Peglow Mirko 
Published: January 2007

AbstractThe goal of this work is the simulation of concentration and temperature distributions insides fluidized bed with a uniform liquid distribution. Further, a physically based 2D model is developed for the heat and mass transfer processes in fluidized beds with a spray nozzle. The model is a coupled and semi‐linear system of convection‐reaction‐diffusion equations. We considered the numerical solution of these semi‐linear partial differential equations with discrete boundary conditions using linear finite elements on an adaptive triangular grid in space and implicit methods in time. We present calculations using, semi implicit and implicit methods in time, and different solvers for solving the linear systems. The complex correlations of mass and liquid flow rates, mass transfer, heat transfer, drying, and transient two dimensional air humidity, air temperature, degree of wetness, liquid film temperature and particle temperature were simulated. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Radiation, Frequency Averaging and Proper Orthogonal Decomposition
Authors: Pinnau René , Schulze Alexander 
Published: January 2007

AbstractWe study proper orthogonal decomposition (POD) for frequency averaging in radiative heat transfer. Especially, we employ the method of snapshots to devise an automated a posteriori algorithm, which helps to reduce significantly the dimensionality for further simulations. The reliability of the surrogate models is tested and we present several numerical results underlining the feasibility of our approach. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Decoupling of Abstract DAEs
Authors: Reis Timo 
Published: January 2007

AbstractWe consider linear and time‐invariant abstract differential‐algebraic equations (DAEs) which are equations of the form E $ \dot x $(t) = Ax (t) + f (t), x (0) = x0. x (·) and f (·) are functions with values in Hilbert spaces X and Z and the operator E: X → Z is assumed to be bounded, whereas A is closed and defined on some dense subspace D (A). Motivated by the Kronecker normal form for the finite dimensional case, the decoupling of abstract DAEs is investigated. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical Stokes Flow Estimation: An Imaging‐Based Control Approach
Authors: Ruhnau Paul , Schnörr Christoph 
Published: January 2007

AbstractWe present an approach to particle image velocimetry based on optical flow estimation subject to physical constraints. Admissible flow fields are restricted to vector fields satifying the Stokes equation. The latter equation includes control variables that allow to control the optical flow so as to fit to the apparent velocities of particles in a given image pair. We show that when the real unknown flow observed through image measurements conforms to the physical assumption underlying the Stokes equation, the control variables allow for a physical interpretation in terms of pressure distribution and forces acting on the fluid. Although this physical interpretation is lost if the assumptions do not hold, our approach still allows for reliably estimating more general and highly non‐rigid flows from image pairs and is able to outperform cross‐correlation based techniques. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mechanical and morphological characterization of PVC plastisol composites with almond husk fillers
Authors: Crespo J.E. , Sanchez L. , Parres F. , López J. 
Published: January 2007

AbstractThe present study develops new composite materials derived from environmentally friendly material, based on lignocellulosic fillers combined with a thermoplastic matrix. Almond husk, obtained as a by‐product of the agri‐food industry, has been used as a filler, combined with PVC thermoplastic matrix. This composite type (lignocellulosic material/thermoplastic matrix) is the object of this work for the advantages that it offers in environmental protection terms. With a view to identifying the degree of influence of filler amount, plasticizer concentration, and filler particle size on the properties of this new composite, we tested its mechanical properties and analyzed tensile fracture surfaces using scanning electron microscopy. POLYM. COMPOS., 28:71–77, 2007. © 2007 Society of Plastics Engineers
Fluorescence quenching of phenanthrene and anthracene by maleic anhydride and n‐octadecenylsuccinic anhydride in solution and in bulk polypropylene
Authors: Fang Haixia , Mighri Frej , Ajji Abdellah 
Published: January 2007

AbstractFluorescence quenching of phenanthrene (Ph) and anthracene (An) fluorophores by maleic anhydride (MAH) and n‐octadecenylsuccinic anhydride (ODSA) quenchers in solid polypropylene (PP) films were studied. Results were compared with fluorescence quenching of the same fluorophores by MAH and ODSA quenchers in chloroform solution. Contrary to the results obtained in solution, it was observed that fluorescence emission of Ph fluorophore in PP films was more efficiently quenched by ODSA than by MAH. This was due to the better miscibility of Ph with ODSA than with MAH. When An fluorophore was used instead of Ph, it was observed that its fluorescence intensity in PP films was notably reduced by the addition of MAH. This was mainly due to the Diels–Alder reaction, which consumed a part of the An molecule. However, fluorescence intensity of An strangely increased with the addition of ODSA instead of MAH. Because of short lifetime of An (around 6 ns), ODSA had no quenching effect on An. POLYM. ENG. SCI., 47:192–199, 2007. © 2007 Society of Plastics Engineers
Perfectionism and depressive symptoms in early adolescence
Authors: Rice Kenneth G. , Leever Brooke A. , Noggle Chad A. , Lapsley Daniel K. 
Published: January 2007

AbstractThe Adaptive/Maladaptive Perfectionism Scale (AMPS; K.G. Rice & K.J. Preusser, 2002) was developed on samples of 9‐ to 11‐year‐old children. A primary purpose of the current research was to examine whether the AMPS could be useful in studies of adolescents, and in particular, studies of adolescent depression. This study of 145 early adolescents revealed (1) a somewhat different AMPS factor structure than has been evident in studies of younger children; (2) no significant mean differences between boys and girls on perfectionism, although girls were significantly more depressed than boys; (3) a pattern of perfectionism‐depression correlations that differed somewhat between boys and girls; and (4) several interactions of different dimensions of perfectionism in accounting for depression. Results are discussed by addressing differences between children and adolescents in school cultures, physical and psychological changes from childhood to adolescence, and the importance of considering the positive as well as the negative aspects of perfectionism among school‐age children. © 2007 Wiley Periodicals, Inc. Psychol Schs 44: 139–156, 2007.
The role of TAP1 and TAP2 gene polymorphism in idiopathic bronchiectasis in children
Authors: Doğru Deniz , Özbaş Gerçeker Filiz , Yalçın Ebru , Çobanoğlu Nazan , Pekcan Sevgi , Özçelik Uğur , Kiper Nural , Özgüç Meral 
Published: January 2007

AbstractBronchiectasis is characterized by permanent changes in the structure and function of the airways. Its cause cannot be identified in some cases. A genetic disease can predispose to bronchiectasis in our country, where consanguinity of parents is common. Transporter associated with antigen presentation (TAP) deficiency syndrome is characterized by recurrent bacterial lower respiratory tract infections, which cause bronchiectasis. Our aim was to document the relationship between idiopathic bronchiectasis and TAP gene polymorphisms. Forty‐four patients with idiopathic bronchiectasis and 100 healthy individuals as the control group were included. DNA was extracted and gene polymorphisms for TAP1 and TAP2 were studied. When compared to healthy controls, in the patient group, Ile/Ile genotype was decreased and Ile/Val genotype was increased in TAP1‐333 polymorphism analysis; Asp/Asp and Gly/Gly genotypes were decreased and Asp/Gly frequency was increased in TAP1‐637 polymorphism analysis; Ile/Val genotype was increased and Ile/Ile genotype was decreased in TAP2‐379 polymorphism analysis; and Thr/Thr genotype frequency was decreased and Thr/Ala and Ala/Ala genotypes were increased in TAP2‐665 polymorphism analysis. No statistically significant difference between patient and control groups was noted only in TAP2‐565 polymorphism analysis. These results indicate that TAP gene polymorphisms may have had a role in the development of bronchiectasis in our patient group. Therefore, TAP deficiency syndrome should be considered in children with idiopathic diagnosis, since early diagnosis of the disease will improve life quality and survival. Pediatr Pulmonol. 2007; 42:237–241. © 2007 Wiley‐Liss, Inc.
Topological map learning from outdoor image sequences
Authors: He Xuming , Zemel Richard S. , Mnih Volodymyr 
Published: January 2007

AbstractWe propose an approach to building topological maps of environments based on image sequences. The central idea is to use manifold constraints to find representative feature prototypes, so that images can be related to each other, and thereby to camera poses in the environment. Our topological map is built incrementally, performing well after only a few visits to a location. We compare our method to several other approaches to representing images. During tests on novel images from the same environment, our method attains the highest accuracy in finding images depicting similar camera poses, including generalizing across considerable seasonal variations. © 2007 Wiley Periodicals, Inc.
Field emission devices for space applications
Authors: Rüdenauer Friedrich G. 
Published: January 2007

AbstractIn the late 1950s, interest arose in the US to use electrostatic droplet sprayers as a new heavy charged particle source for electric space propulsion. Originally, charged droplets were produced from conductive organic liquids. Around 1960, first attempts were made to use liquid metals as the charge material. It was discovered that the device was a very high brightness source of metal ions, which could be focused to spots of nanometer dimensions. This liquid metal ion source (LMIS) has developed into a commercially exploited device for ion microbeam technology. In Europe, the potential of the LMIS as a very high specific impulse ion thruster has been recognized. Since the 1970s, development of cesium and, later, indium ion thrusters has been going on. Presently, the development is at an advanced stage. Contracts have been issued by ESA to equip microsatellites with an attitude control system based on field (ion) emission electric propulsion (FEEP). The first technological test to verify microgravity operation of the indium LMIS was performed in 1991 on the Russian MIR space station, and from 1992 the device has been exploited for active potential control of scientific satellites and for on‐site planetary mass spectrometry in seven space missions. The first gas field‐ionization source was flown as early as 1977 on a sounding rocket and in 1986 to comet Halley. Apart from these field emission devices actually flown, field ion‐ and electron devices are under development or discussion for a number of other space applications. The latest developments and future prospects are discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Investigation of new aspects in the initial stages of decomposition of Cu2at.%Co with the tomographic atom probe and the field ion microscope
Authors: Heinrich Alexander , Al‐Kassab Tala'at , Kirchheim Reiner 
Published: January 2007

AbstractThe initial stages of nucleation and precipitation of the Co‐rich phase in a supersaturated Cu2at.%Co alloy were studied with the field ion microscope (FIM) and the tomographic atom probe (TAP). The specimens of nominal composition Cu2at.%Co were homogenised at 1173 K and aged for different times at different temperatures from 703 to 853 K to follow the decomposition path at these reaction temperatures. In this paper, results on the time evolution of the decomposition are presented. New aspects in the decomposition of CuCo were found, which are discussed. At the initial stages of the nucleation, fluctuations were observed, which could be quantitatively characterised.Decomposition was found to take different paths at different annealing temperatures. At 853 K individual precipitates grew, whereas during coarsening the elastic soft [100] directions were preferred.At 763 K, cigar‐shaped precipitates formed along the [100] directions as a metastable state, which degraded into individual spherical precipitates for longer aging times. The initial stages of decomposition were also characterised for 703 K by using the cluster search algorithm. Copyright © 2007 John Wiley & Sons, Ltd.
Chemical composition and fermentation characteristics of grain and different parts of the stover from maize land races harvested at different growing periods in two zones of central Mexico
Authors: Estrada-Flores J. G. , González-Ronquillo M. , Mould F.L. , Arriaga-Jordán C. M. , Castelán-Ortega O. A. 
Published: January 2007

AbstractThe objective of this work was to determine the rumen fermentation characteristics of maize land races used as forage in central Mexico. In vitro gas production (ml per 200 mg dry matter (DM)) incubations were carried out, and cumulative gas volumes were fitted to the Krishnamoorthyet al.(1991) model. The trial used a split-plot design with cultivation practices associated with maize colour (COL) as the main plot with three levels: white, yellow and black maize; growing periods (PER) were the split plots where PER1, PER2 and PER3 represented the first, second and third periods, respectively and two contrasting zones (Z1=valley and Z2=mountain) were used as blocking factors. The principal effects observed were associated with the maturity of the plants and potential gas production increased (P<0·05) in stems (PER1=51·8, PER2=56·3, PER3=58·4 ml per 200 mg DM) and in whole plant (PER1=60·9, PER2=60·8, PER3=70·9 ml per 200 mg DM). An inverse effect was observed with fermentation rates in leaves (P<0·01) with 0·061, 0·053 and 0·0509 (per h) and in whole plant (P<0·05) with 0·068, 0·057, 0·050 (per h) in PER1, PER2 and PER3 respectively. The digestibility of the neutral-detergent fibre (NDF) decreased with maturity especially in leaves (P<0·05) with values of 0·71, 0·67 and 0·66 g/kg; in rachis (P<0·01) 0·75, 0·72, and 0·65 in PER1, PER2 and PER3 respectively. The NDF content in leaves in leaves (668, 705 and 713 g/kg DM for PER1, PER2 and PER3, respectively), stems (580, 594 and 644 g/kg DM) and, husk (663, 774 and, 808 g/kg DM) increased (P<0·05) with increasing plant maturity, rachis were significantly different between periods (P<0·01). The structure with the best nutritive characteristics was the husk, because it had the lowest fibre contents, especially in acid-detergent lignin, with values of 22·6, 28·6 and 37·6 g/kg DM in PER1, PER2 and PER3, respectively.
Genetic variation in serum copper concentration in Angus cattle
Authors: Morris C. A. , Amyes N. C. , Hickey S. M. 
Published: January 2007

AbstractFollowing the discovery of low serum copper (Cu) concentrations in 9-month-old beef calves at pasture in autumn (50% of animals had values <7·5 μmol/l), genetic variation in serum Cu concentration was studied in an experimental Angus herd in New Zealand, monitoring at intervals from about 7 to 17 months of age. The study was initiated in autumn when animals were supplemented with zinc (Zn) salts (to protect against liver injury from toxin-producing facial eczema spores on the pasture), and later in the production year after Cu supplementation but without Zn supplementation. Heritabilities of Cu concentration were estimated in 837 calves from six calf crops, the progeny of 47 sires, using restricted maximum likelihood procedures with an animal model. Correlations between Cu concentration and Zn concentration were also estimated, along with correlations between Cu concentration and 6-month, 9-month and yearling live weights. The heritability estimate for Cu concentration at all times outside the autumn Zn supplementation period was 0·28±0·08 (between-animal repeatability, 0·30±0·05), and the heritability estimates for autumn Cu concentration and Zn concentration were 0·35±0·11 and 0·26±0·13, respectively. The genetic and environmental correlations between autumn Cu concentration and Zn concentration were ?0·29±0·31 and 0·15±0·11, respectively, suggesting antagonistic effects between Zn and Cu only at the genetic level, with a net (phenotypic) correlation of 0·02±0·06. Genetic correlations between Cu concentration (outside the autumn season) and 6-month, 9-month and yearling weights ranged from 0·15±0·15 to 0·17±0·16. It was concluded that serum Cu and Zn concentrations in calves were heritable traits under the grazing conditions encountered, and that index selection to increase live weights and Cu concentrations could be applied if desired.