bluuebunny/crossref_metadata_2025_split huggingface dataset:
Duct flow with a transverse magnetic field at high Hartmann numbers
Authors: Barrett K. E. 
Published: August 2002

AbstractFinite element methods can be used for determining the flow in a straight channel under a variety of wall conductivity conditions when a uniform magnetic field is imposed perpendicular to the flow direction. At high Hartmann numbers oscillatory solutions are found unless sufficient points are placed within the Hartmann layers. In some one‐ and two‐dimensional problems it appears that it is adequate to place one or two points within the Hartmann layer to remove the oscillations. Central core values can sometimes be predicted with good accuracy even when the Hartmann layers are not resolved adequately. A nine‐point Gauss point rule has been used to evaluate the stiffness and other matrices for the eight‐node elements. Copyright © 2001 John Wiley & Sons, Ltd.
All‐hexahedral mesh smoothing with a node‐based measure of quality
Authors: Calvo N. A. , Idelsohn S. R. 
Published: August 2002

AbstractThis research work deals with the analysis and test of a normalized‐Jacobian metric used as a measure of the quality of all‐hexahedral meshes. Instead of element qualities, a measure of node quality was chosen. The chosen metric is a bound for deviation from orthogonality of faces and dihedral angles. We outline the main steps and algorithms of a program that is successful in improving the quality of initially invalid meshes to acceptable levels. For node movements, the program relies on a combination of gradient‐driven and simulated annealing techniques. Some examples of the results and speed are also shown. Copyright © 2001 John Wiley & Sons, Ltd.
On non‐linear transformations for accurate numerical evaluation of weakly singular boundary integrals
Authors: Singh Krishna M. , Tanaka Masataka 
Published: August 2002

AbstractThis paper presents a study of the performance of the non‐linear co‐ordinate transformations in the numerical integration of weakly singular boundary integrals. A comparison of the smoothing property, numerical convergence and accuracy of the available non‐linear polynomial transformations is presented for two‐dimensional problems. Effectiveness of generalized transformations valid for any type and location of singularity has been investigated. It is found that weakly singular integrals are more efficiently handled with transformations valid for end‐point singularities by partitioning the element at the singular point. Further, transformations which are excellent for CPV integrals are not as accurate for weakly singular integrals. Connection between the maximum permissible order of polynomial transformations and precision of computations has also been investigated; cubic transformation is seen to be the optimum choice for single precision, and quartic or quintic one, for double precision computations. A new approach which combines the method of singularity subtraction with non‐linear transformation has been proposed. This composite approach is found to be more accurate, efficient and robust than the singularity subtraction method and the non‐linear transformation methods. Copyright © 2001 John Wiley & Sons, Ltd.
Fixed‐lag smoothing and state estimation in dynamic electrical impedance tomography
Authors: Vauhkonen P. J. , Vauhkonen M. , Kaipio J. P. 
Published: August 2002

AbstractIn electrical impedance tomography (EIT), an approximation for the internal resistivity distribution is computed based on the knowledge of the injected currents and measured voltages on the surface of the body. The conventional approach is to inject several different current patterns and use the associated data for the reconstruction of a single distribution. This is an ill‐posed inverse problem. In some applications the resistivity changes may be so fast that the target changes between the injection of the current patterns and thus the data do not correspond to the same target distribution. In these cases traditional reconstruction methods yield severely blurred resistivity estimates. We have earlier proposed to formulate the EIT problem as an augmented system theoretical state estimation problem. The reconstruction problem can then be solved with Kalman filter and Kalman smoother algorithms. In this paper, we use the so‐called fixed‐lag smoother to solve the dynamic EIT reconstruction problem. We show that data storage difficulties that are associated with the previously used fixed‐interval smoother can be avoided using the fixed‐lag smoother. The proposed methods are compared with simulated measurements and real data. Copyright © 2001 John Wiley & Sons, Ltd.
The extended finite element method for rigid particles in Stokes flow
Authors: Wagner G. J. , Moës N. , Liu W. K. , Belytschko T. 
Published: August 2002

AbstractA new method for the simulation of particulate flows, based on the extended finite element method (X‐FEM), is described. In this method, the particle surfaces need not conform to the finite element boundaries, so that moving particles can be simulated without remeshing. The near field form of the fluid flow about each particle is built into the finite element basis using a partition of unity enrichment, allowing the simple enforcement of boundary conditions and improved accuracy over other methods on a coarse mesh. We present a weak form of the equations of motion useful for the simulation of freely moving particles, and solve example problems for particles with prescribed and unknown velocities. Copyright © 2001 John Wiley & Sons, Ltd.
Alternative time marching process for BEM and FEM viscoelastic analysis
Authors: Mesquita A. D. , Coda H. B. , Venturini W. S. 
Published: August 2002

AbstractBased on the weighted residual technique, both Finite Element and Boundary Element alternative procedures for viscoelastic analysis are proposed. After imposing the space approximations, applying the kinematical relations for material and strain velocities at the approximation level, the time integration is carried out using appropriate operators. The Kelvin‐Voigt viscoelastic model is implemented in order to validate the idea. The Newmark β time integral scheme is applied to the Finite Element procedure while the Houbolt scheme is applied to the Boundary Elements, allowing the consideration of dynamic analysis in future works. Copyright © 2001 John Wiley & Sons, Ltd.
Stress resultant geometrically exact form of classical shell model and vector‐like parameterization of constrained finite rotations
Authors: Ibrahimbegovic A. , Brank B. , Courtois P. 
Published: August 2002

AbstractIn this work we consider the geometrically exact shell model subjected to finite rotations, making use of rotation vector parameters for handling the corresponding constrained rotation for smooth shells. A modification of such a parameterization which is based on the incremental rotation vector and thus capable of avoiding the singularity problem is also discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Mathematical model of soil freezing and its numerical implementation
Authors: Mikkola M. , Hartikainen J. 
Published: August 2002

AbstractA mathematical model is presented to predict the evolution of freezing of water‐saturated soil. It is based on the theory mixtures and the principles of continuum mechanics and macroscopic thermodynamics. The numerical solution of the problem is accomplished using an enriched family of interpolation functions. Copyright © 2001 John Wiley & Sons, Ltd.
Changing fish use on Mangaia, southern Cook Islands: resource depression and the prey choice model
Authors: Butler Virginia L. 
Published: August 2002

AbstractThis study applies the prey choice model from foraging theory to explain changing human use of fish during the 700‐year occupation of Tangatatau Rockshelter, Mangaia, southern Cook Islands. The prey choice model suggests that predators will focus initially on high ranked prey, turning to lower ranked prey if abundance of higher ranked prey declines. It is suggested that increasing human population size would have resulted in increases in harvesting pressure and ultimately prey resource depression. To apply the prey choice model to archaeological faunal records and based on previous research, prey ranks are estimated using overall attributes of taxon body size; the larger the taxon, the higher the rank. Two indices, the Marine and Freshwater Fish Index, are developed to estimate the ratio of high to low ranked prey and are calculated for each zone of the rockshelter. Over time, the indices show a decreasing abundance of high ranked prey and increasing abundance of low ranked prey, which supports the view of resource depression. Skeletal elements from two of the high ranked prey, Serranidae and Anguilla sp., are measured to examine taxon‐specific changes in fish body size/age that would indicate direct human exploitation pressure. Evidence for a decline in Serranidae body size over time suggests that some of the decline in prey abundance and encounter rates results from direct harvesting pressure along with behavioural adjustments in the prey. Sample sizes for Anguilla were insufficient for statistical treatment. Environmental and technological factors that might also affect prey abundance and taxonomic representation do not satisfactorily account for the patterns. Overall, the increasing use of lower ranked prey suggests a decline in foraging efficiency, given higher energetic costs associated with their use. The study adds to a growing body of evidence that Polynesians profoundly affected the indigenous biota on islands they colonized. Copyright © 2001 John Wiley & Sons, Ltd.
Optimal control of deterministic epidemics
Authors: Behncke Horst 
Published: August 2002

AbstractVarious deterministic optimal control models for SIR‐epidemics are investigated in this paper. The epidemics are governed by a rather general interaction, which covers most cases studied in the literature. Vaccination, quarantine, screening or health promotion campaigns as forms of control are considered. In all cases one finds a maximum effort control on some initial time interval. In addition, uniqueness and monotonicity properties of these models are studied. The results are also extended to the infinite time‐horizon situation. Copyright © 2000 John Wiley & Sons, Ltd.
Asymmetric hydroformylation of vinyl acetate catalyzed by zeolite‐supported gelatin–Co–Ru complex
Authors: Zhang Xi , Han Bing , Huang Mei‐Yu , Jiang Ying‐Yan 
Published: August 2002

AbstractZeolite‐supported gelatin–cobalt–ruthenium complex (zeo–gelatin–Co–Ru) was prepared by a simple method, first the zeolite and gelatin (chiral natural bio‐polymer) were mixed to give zeolite‐supported gelatin (zeo–gelatin), then this was used as a polymer ligand to react with CoCl2·6H2O and RuCl3·H2O to form the complex. This complex has been found to catalyze the asymmetric hydroformylation of vinyl acetate to give (R)‐2‐acetoxy‐propanal in 83.4% product yield and 90.9% optical yield. And this catalyst could be reused several times without any considerable change in the optical yield. Copyright © 2001 John Wiley & Sons, Ltd.
Estimation of free radical‐quenching activity of leaf pigment extracts
Authors: Arnao Marino B. , Cano Antonio , Alcolea Jesús F. , Acosta Manuel 
Published: August 2002

AbstractThe chromogen 2,2′‐azino‐bis‐(3‐ethylbenzthiazoline‐6‐sulphonic acid) radical (ABTS·+) can be directly generated by the enzymatic system formed by hydrogen peroxide and horseradish peroxidase in ethanolic media. The reaction is time‐ and concentration‐dependent, and the ABTS·+ generated shows excellent stability. The method is an adaptation of the decolouration method previously reported (Cano et al. 1998. Phytochem Anal 9:196–202), which was used for estimating anti‐oxidant activity in aqueous media. When the assay described here was used to quantify the anti‐oxidant activity of two anti‐oxidants, Trolox (an analogue of vitamin E) and β‐carotene, the latter had 2.5 times better anti‐oxidant capacity than Trolox at the same concentration. The free radical quenching activity (anti‐oxidant activity) of leaf pigment extracts was measured and related to the the carotenoid contents in leaf extracts of barley, oat and citrus. The possibilities of using this experimental approach to evaluate the status of photoprotective pigments are discussed. Copyright © 2001 John Wiley & Sons, Ltd.
High‐performance liquid chromatographic separation of natural and synthetic desulphoglucosinolates and their chemical validation by UV, NMR and chemical ionisation‐MS methods
Authors: Kiddle Guy , Bennett Richard N. , Botting Nigel P. , Davidson Nicola E. , Robertson Avril A. B. , Wallsgrove Roger M. 
Published: August 2002

AbstractMethods are described for the optimised extraction, desulphation and HPLC separation of desulphoglucosinolates. These methods provide rapid separation, identification and quantitative measurements of glucosinolates extracted from Brassica napus L and related crops, of unusual glucosinolates found in crucifer weed species, and also of synthetic alkylglucosinolates. The desulphoglucosinolates used in these studies were either chemically synthesised (at least one example from each major structural class), or purified from various plant sources. Validation of the identities of the desulphoglucosinolates was by comparison of retention times with standards, and by UV, 1H‐ and 13C‐NMR and chemical ionisation MS analysis. A list of useful species, and the specific tissues, from which high concentrations of standards can be extracted is included. Copyright © 2001 John Wiley & Sons, Ltd.
A rapid capillary gel electrophoresis method for the quantitative determination of RuBisCo in spinach
Authors: Nicholas Kumudini U. K. G. , Forney Charles F. , Paulson Allan T. 
Published: August 2002

AbstractA capillary gel electrophoretic (CGE) method for the quantitative analysis of RuBisCo in spinach leaves was developed. RuBisCo was resolved into large and small subunits in the presence of sodium dodecyl sulphate (SDS) by the CGE procedure which enabled the determination of the molecular weight of each unit accurately; the values so determined were in close agreement with those reported using other methods. Advantages of CGE over SDS–polyacrylamide gel electrophoresis and high‐pressure gel filtration include decreased sample preparation and analysis time, superior resolution and greater sensitivity permitting reduced sample size and trace analysis. In addition, CGE provided precise quantification of RuBisCo and was demonstrated to be a viable alternative to other available methods of protein analysis. Copyright © 2001 John Wiley & Sons, Ltd.
Variation in uptake of serum screening: the role of service delivery
Authors: Dormandy Elizabeth , Michie Susan , Weinman John , Marteau Theresa M. 
Published: August 2002

AbstractThe present study aimed to determine the extent to which variation in the uptake of serum screening for Down syndrome reflects variation in the way the test is offered. A higher uptake of serum screening was seen at hospitals that offered the blood test as part of a routine visit than at those where screening required a separate visit. The type of screening test offered and whether a reminder was sent were not associated with uptake. Given the consensus that undergoing screening should be the result of an informed choice, further research is needed to determine which methods of offering serum screening facilitate and which impede informed choice. Copyright © 2002 John Wiley & Sons, Ltd.
Intrauterine growth restriction (IUGR): biometric and Doppler assessment
Authors: Galan Henry L. , Ferrazzi Enrico , Hobbins John C. 
Published: August 2002

AbstractIntrauterine growth restriction (IUGR) is a common complication in pregnancy and influences morbidity and mortality at all stages of life. Historically, the management of IUGR has been dependent on antenatal biophysical testing and umbilical artery Doppler studies. With recent Doppler studies of the fetal central circulation, including intracardiac flows and the ductus venosus, better timing of delivery to minimize morbidity may be possible. This review will provide the reader with tools to diagnose IUGR, more accurately date the IUGR pregnancy with poor dating criteria, and better assess the condition of the IUGR fetus. A brief review of animal models of IUGR is presented to demonstrate research directions for answering human clinical questions and potentially carrying therapeutic intervention from the bench to the bedside. Copyright © 2002 John Wiley & Sons, Ltd.
Alpha‐thalassaemia prenatal diagnosis by two PCR‐based methods
Authors: Kleanthous M. , Kyriacou K. , Kyrri A. , Kalogerou E. , Vassiliades PH. , Drousiotou A. , Kallikas I. , Ioannou P. , Angastiniotis M. 
Published: August 2002

AbstractIn Cyprus all couples carrying α0‐thalassaemia mutations are detected in the course of the thalassaemia carrier screening program and prenatal diagnosis is offered to all of them. Prenatal diagnosis for α‐thalassaemia is routinely done by two independent molecular methods. With the first method, the mutations of the parents are directly determined by gap‐PCR and then the chorionic villus sample (CVS) is examined for the presence of these mutations. With the other method, a (CA)n repeat polymorphic site located between the ψα1‐ and α2‐globin genes is used for determining the presence or absence of the normal and mutant alleles. In the period from 1995 to 1999, molecular analysis of 46 couples in which haematological data were consistent with deletion of two α‐globin genes in both partners indicated that only 13 of them were actually at risk for haemoglobin (Hb) Bart's hydrops fetalis and prenatal diagnosis was provided in 16 pregnancies. The molecular diagnosis was possible in all cases with the use of both gap‐PCR and (CA)n repeat polymorphisms analysis. No misdiagnosed cases for α‐thalassaemia have been reported to date. Copyright © 2001 John Wiley & Sons, Ltd.
Antenatal gene tests in low‐risk pregnancies: molecular screening for aspartylglucosaminuria (AGU) and infantile neuronal ceroid lipofuscinosis (INCL) in Finland
Authors: Kallinen Juuso , Heinonen Seppo , Palotie Aarno , Mannermaa Arto , Ryynanen Markku 
Published: August 2002

AbstractApproximately one in five subjects in Finland carries some gene defect associated with 30 diseases belonging to the Finnish disease heritage, and about one in 500 children born is affected. Almost all carriers, women and men, are unaware of their condition. Recent advances in molecular medicine have offered the possibility of population‐based carrier screening for recessive disorders. We studied acceptance and attitudes to antenatal screening for aspartylglucosaminuria (AGU) and infantile neuronal ceroid lipofuscinosis (INCL).From January 1995 until December 1996 carrier tests were offered at Kuopio City Health Center, free of charge to all pregnant women attending maternity care units. Women found to be carriers of AGU (n=47) or INCL (n=14) underwent detailed genetic counseling, and their male partners were also offered the test. If both partners appeared to be carriers we offered prenatal testing (n=1). No affected fetuses were detected. Attitudes towards the gene test were elicited by means of a questionnaire.Altogether 87% of pregnant women elected to undertake the gene tests. Antenatal screening for gene defects was feasible and well accepted, and it provided an effective way to find carriers of genetic diseases and to incorporate prenatal testing into this process. Copyright © 2001 John Wiley & Sons, Ltd.
The effect of hexamethylene diisocyanate modified ALCELL lignin as a coupling agent on the flexural properties of oil palm empty fruit bunch – polypropylene composites
Authors: Rozman H D , Tan K W , Kumar R N , Abubakar A 
Published: August 2002

AbstractALCELL lignin has been employed as a coupling agent in oil palm empty fruit bunch (EFB)–polypropylene (PP) composites. The lignin has been chemically modified with hexamethylene diisocyanate (HMDI). Evidence for the reaction between HMDI and lignin has been observed by using Fourier transform infrared (FTIR) analysis. The effect of lignin as a coupling agent on the flexural properties has been studied. The results show that the HMDI‐modified lignin is able to impart greater compatibility between EFB and PP. This is reflected in the greater flexural strength shown by the composites with HMDI‐modified lignin than those with the unmodified lignin. Scanning electron microscopy studies show that HMDI‐modification of lignin results in a better blending and compatibility between lignin and PP matrix. The glass transition temperature of lignin increases as the level of HMDI modification is increased.© 2001 Society of Chemical Industry
Addition‐cure phenolic resins based on propargyl ether functional novolacs: synthesis, curing and properties
Authors: Bindu R L , Reghunadhan Nair C P , Ninan K N 
Published: August 2002

AbstractThermosetting phenolic resins, bearing varying extents of propargyl ether groups (PN resins), have been synthesized by the Williamson reaction of a novolac with propargyl bromide and the products characterized. The resin precursors were cured through Claisen rearrangement of the propargyl ether groups and thermal polymerization. The activation energy for thermal cure is substantially lower than that of model bispropargyl ether compounds but is quite independent of the degree of functionalization. The isothermal cure profile, extrapolated from non‐isothermal DSC kinetics studies is consistent with the results from DMA studies. The mechanical properties of glass composites of the resins, of varying propargyl contents, reveal good consolidation of the interphases, evident from the initial gain in both interlaminar shear strength (ILSS) and flexural strength. The benefits of better resin–reinforcement interactions are not retained on crosslinking the resin further, wherein the composite fails by a combination of fibre debonding and brittle fracture of the matrix. Although the resins show better thermal stability than cured resoles, a higher extent of propargylation is detrimental for the thermal stability. Resins with moderate propargylation show good mechanical and thermal properties.© 2001 Society of Chemical Industry
Modification of polysiloxane polymers for biomedical applications: a review
Authors: Abbasi Farhang , Mirzadeh Hamid , Katbab Ali‐Asgar 
Published: August 2002

AbstractThis paper reviews methods of modifying polydimethylsiloxane (PDMS) polymers to improve their properties for biomedical applications. The modification methods are discussed under three different categories: bulk, surface and other modification techniques. Surface modification techniques include physical and chemical techniques to modify polymer surfaces. Bulk modification techniques include blending, copolymerization, interpenetrating polymer networks (IPNs) and functionalization. The third category includes less common modification techniques.© 2001 Society of Chemical Industry
End‐group determination in poly(ethylene terephthalate) by infrared spectroscopy
Authors: Al‐AbdulRazzak Sami , Lofgren Elizabeth A , Jabarin Saleh A 
Published: August 2002

AbstractA complete infrared (IR) spectroscopy experimental procedure was used to determine end‐group concentrations of poly(ethylene terephthalate) (PET). The correlations of the hydroxyl and carboxyl units were derived independently for accurate calibration results. The intermediate monomer of PET, bis(hydroxyethyl terephthalate), was used to prepare hydroxyl end‐group standards and titration measurements were used to determine the carboxyl content for the carboxyl end‐group standards. A double‐Gaussian form equation was defined to account for the interference between the hydroxyl and the carboxyl absorbance peaks in the PET IR spectrum. Some deviation was found from the assumption traditionally used for end‐group determination, stating that carboxyl and hydroxyl are the only end‐group units available in PET.© 2002 Society of Chemical Industry