bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hierarchic and mixed‐interpolated finite elements for Reissner–Mindlin problems
Authors: Scapolla T. , Della Croce L. 
Published: August 2005

AbstractThe focus of the present work is directed towards the construction of a family of special finite elements for the numerical solution of the Reissner–Mindlin plate problem. The model describes the deformation of a plate when transverse shear deformation is taken into account. The model is widely used for thin to moderately thick plates. Despite its simple formulation, the numerical approximation is not straightforward. When standard low‐order finite elements are used for the approximation the solution degenerates very rapidly for small thickness (locking phenomenon). To overcome such behaviour, non‐standard formulations of the problem are usually combined with low‐order finite elements to weaken or possibly eliminate the locking of the numerical solution.In recent years high‐order finite elements have been introduced and successfully applied in several fields. Previously we have constructed a family of hierarchic high‐order finite elements to solve the Reissner–Mindlin problem in its plain formulation. The locking was strongly reduced but was still active for very thin plates. Meanwhile some mixed‐interpolated finite elements have been developed and shown to be locking free. In this paper we combine the two approaches, namely, the hierarchic high‐order elements and the mixed‐interpolated elements. The result is a family of special finite elements that exhibits both properties of convergence and robustness.
A laminate theory based on global–local superposition
Authors: Li Xiaoyu , Liu Dahsin 
Published: August 2005

AbstractCombining a high‐order shear deformation theory and a layerwise theory, a laminate theory of zigzag type is presented. Like the high‐order shear deformation theories, the number of independent variables of the present theory is independent of layer number. The numerical efficiency is thus guaranteed. Similar to the layerwise theories, the in‐plane displacement components vary from layer to layer. Hence, the imposition of continuity conditions of interlaminar shear stresses on the laminate interfaces becomes possible. Consequently, the accuracy of displacement and stress components can be improved. Numerical studies on composite laminates made of alternate sequences based on 0° and 90° layers are performed. It can be concluded that the present theory gives accurate in‐plane displacement and stress for 6‐layer, 19‐layer and 32‐layer laminates. Its predictions on transverse displacement, transverse shear stress and transverse normal stress seem to be gradually improved as the number of alternate layers increases.
An accurate finite strip for analysing deep beams and shear walls
Authors: Cheung Y. K. , Kong J. 
Published: August 2005

AbstractA new finite strip for the analysis of 2D elastic problems is presented. Displacement in each of the two in‐plane directions is interpolated by a set of computed shape functions in the longitudinal direction and, as usual, standard 1D Lagrangian shape functions in the transverse direction. Unlike all other finite strips, the unknown parameters of the present finite strip are represented by the physical displacement variables at nodal points. Furthermore, C0‐continuity is maintained across the boundaries between adjacent strips. Deep beams with geometric discontinuity can be treated in a standard finite element manner. Several numerical examples are given to demonstrate its accuracy in analysing deep beams and shear walls.
On the completeness of the multiple reciprocity series approximation
Authors: Power Henry 
Published: August 2005

AbstractIn the paper we apply the boundary element multiple reciprocity method to the Brinkman equation, showing that the technique yields an incomplete series representation of the corresponding fundamental solution, incompleteness that is due to a weakness in the way the method is usually applied. For the present case an additional integral relation is found that makes the series complete. Unfortunately, the relation is particular to this problem and cannot be generalized in a simple way. The result found in this work suggests that in multiple reciprocity it is necessary to have an extra relation in integral form to define the missing terms in the series representation. This extra relation has to yield zero contribution for cases when the multiple reciprocity method gives the complete series representation.
On the application of 2D potential theory to electrostatic simulation
Authors: Shi Fan , Ramesh Palghat , Mukherjee Subrata 
Published: August 2005

AbstractComputing the charge density on the surfaces of conductors is fundamental to many electrostatic applications. Difficulties arise in two‐dimensional simulation due to the O(log|r|) potential. Fully understanding the 2D potential problem, and reasonably connecting the mathematical formulation with physical interpretation, are key to handling this difficulty properly. In the absence of these factors it is easy for one to propose an ill‐posed problem. In this paper, a complete investigation of potential theory, from 3D to 2D, is made for computing charge density on the surfaces of conductors. Various integral formulations are derived ‐ these are applicable in different situations. It is shown that, in general, the electrostatic potential need not be finite valued at infinity for 2D problems. Numerical examples for the 2D case are constructed to show that the formulations are consistent. Criteria for choosing the most appropriate formulation for a given problem are suggested.
Anti‐kinetochore staining for single laser, bivariate flow sorting of Indian muntjac chromosomes
Authors: Levy Howard P. , Schultz Roger A. , Ordóñez José V. , Cohen Maimon M. 
Published: August 2005

AbstractFlow cytometric chromosome sorting typically relies upon dual‐laser, bivariate analysis after staining with two different base pair‐specific dyes for resolution of chromosomes with similar DNA content. The availability of FITC‐conjugated antibodies offers the possibility of singlelaser bivariate analysis when combined with propidium iodide (PI) DNA staining, but requires exploitable antigenic differences between chromosomes of interest. A technique was developed for indirect immunofluorescent anti‐kinetochore staining of Indian muntjac chromosomes in suspension. Primary antibody binding within permeabilized whole cells minimized centrifugation‐induced loss of chromosomal integrity. Subsequent FITC‐conjugated second antibody binding was not affected by concurrent PI‐counterstaining. Anti‐kinetochore staining facilitated resolution of chromosomes No. 2 and X, which formed a doublet peak upon univariate DNA content analysis, as well as recognition of the Y2 peak which was indistinguishable from debris by univariate analysis. The technique allowed greater than 90% purification of each Indian muntjac chromosome.
Single laser three color immunofluorescence staining procedures based on energy transfer between phycoerythrin and cyanine 5
Authors: Lansdorp Peter M. , Smith Cam , Safford Meredith , Terstappen Leon W. M. M. , Thomas Terry E. 
Published: August 2005

AbstractMonoclonal antibodies specific for phycoerythrin (PE) were covalently labeled with the fluorescent dye cyanine 5 (Cy5). Excitation at 488 nm of immune complexes obtained by mixing Cy5‐anti‐PE with PE resulted in a 4‐fold reduction of PE fluorescence measured at 565 nm and an increase of fluorescence measured at 655 nm. The observed energy transfer between PE and Cy5‐anti‐PE was used to develop three color immunofluorescence staining procedures for flow cytometers equipped with an Argon laser tuned at 488nm. Mouse IgG1 monoclonal antibodies specific for cell surface antigens were cross‐linked with either unlabeled or Cy5 labeled mouse IgG1 anti‐PE using F(ab′)2 fragments of monoclonal rat anti‐mouse IgG1. PE was added to these immune complexes in sufficient amounts to saturate all PE binding sites. Cells were incubated with PE‐labeled and PE/Cy5‐labeled tetrameric antibody complexes together with FITC labeled antibodies and analyzed by flow cytometry. The emission from FITC, PE and PE/Cy5 could be readily separated and bright three color immunofluorescence staining of mononuclear cells from human peripheral blood and bone marrow was observed. The results of these experiments demonstrate that useful probes for single laser three color staining of cell surface antigens can be readily obtained by mixing of selected reagents. Compared to standard procedures for the covalent labeling of PE (tandem) molecules to antibodies, the non‐covalent procedures described in this report provide significant advantages in terms of the amount of reagents, time and equipment required to obtain suitable reagents for three color immunofluorescence staining.
Viral and cellular oncogene expression during progressive malignant transformation of SV40 transformed human fibroblasts
Authors: Goolsby Charles L. , Steiner Marianne , Nemeth Jeffrey 
Published: August 2005

AbstractIn vitro investigation of the multistep neoplastic progression which occurs during transformation of human cells has been hindered by resistance of human cells to both immortalization and tumorigenicity (Mut. Res. 199; 273, 1988). Previously our laboratory established a cell line, HSF4‐T12, by transfection of normal human foreskin fibroblasts with the plasmid pSV3‐neo which contains the early genes of simian virus 40 (SV40). A multi‐step progression in karyotypic alterations and transformed phenotype occurred resulting in a neoplastic cell line that was immortal, transformed, and tumorigenic. We have examined changes in the SV40 proteins, large T (T‐antigen) and small t (t‐antigen) antigens, and in the cellular protein, p53, during progressive transformation of these cells. Total viral protein expression relative to total cellular protein increased following immortalization of HSF4‐T12 as did the ratio of T‐antigen to t‐antigen. Interestingly, no significant change in DNA content accompanied immortalization. However, during the progressive in vitro transformation of HSF4‐T12 which occurred primarily post‐immortalization, DNA index increased to 1.6 but only small additional increases in T‐antigen expression were seen. No consistent or critical role for t‐antigen in development of the tumorigenic phenotype was found in this system.
Elevated serum urate concentration independently predicts poor outcome following stroke in patients with diabetes
Authors: Newman Edward J. , Rahman Fariel S. , Lees Kennedy R. , Weir Christopher J. , Walters Matthew R. 
Published: August 2005

AbstractBackgroundType 2 diabetes is a risk factor for stroke and confers increased risk of poor outcome and further vascular events following stroke. Hyperuricaemia occurs commonly in patients with type 2 diabetes, but its significance as a predictor of outcome following stroke is uncertain. We sought to investigate the prognostic significance of elevated serum urate concentration in diabetic subjects following stroke.MethodsWe studied a cohort of type 2 diabetes patients presenting to our unit with computed tomography‐confirmed acute stroke. Fasting blood samples were drawn within 24 h of admission for urate concentration and standard battery of biochemistry and hematological tests. Information on age, stroke type, prior hypertension, smoking status, resolution time of symptoms and National Institutes of Health Stroke Score was collated. The main outcome event was time to myocardial infarction, recurrent stroke or vascular death, as defined in the CAPRIE trial. Stepwise proportional hazards regression was used to estimate the effect of the above variables on event‐free survival following stroke.ResultsOne hundred and forty patients were studied. Median follow‐up duration was 974 days (IQR 163 to 1830 days). Sixty‐four patients suffered an outcome event. Urate levels of greater than 0.42 mmol/L (p < 0.001) and an increasing NIHSS score (p < 0.001) independently predicted increased likelihood of suffering an event.ConclusionElevated urate concentration is significantly and independently associated with increased risk of future vascular events in diabetic stroke patients. Further studies to elucidate the mechanism of this observation are required. Copyright © 2005 John Wiley & Sons, Ltd.
On conservative finite element formulations of the inviscid Boussinesq equations
Authors: Cliffe K. A. 
Published: August 2005

AbstractThe finite element discretization of the inviscid Boussinesq equations is studied with particular emphasis on the conservation properties of the discrete equations. Methods which conserve the total energy, total temperature and total temperature squared, or two of the above mentioned quantities, are presented. The effect of time discretization, and other numerical errors, on the conservation laws is considered. Finally, the theory is supported and illustrated by several numerical experiments.
A regular boundary element method for fluid flow
Authors: Patterson C. , Sheikh M. A. 
Published: August 2005

AbstractThe Boundary Element Method is now well established as a valid numerical technique for the solution of field problems, equal to the Finite Element Method in generality and surpassing it in computational efficiency in some cases.1 In this paper is presented a 'Regular Boundary Element Method' as applied to inviscid laminar fluid flow problems. It involves the formation of a system of regular integral equations obtained by moving the singularity outside the domain of the given problem. It is also shown that non‐conforming elements may be used whereby freedoms are not defined at the geometric nodes under the boundary element discretization. A linear element is developed here; higher order variants could easily be defined. Satisfactory numerical results have been obtained using the proposed regular method with both conventional (continuous across the boundary) and non‐conforming boundary elements for two‐dimensional inviscid laminar fluid flow problems having regular and singular solutions.
Numerical integration of the shallow water equations over a sloping shelf
Authors: Johns B. 
Published: August 2005

AbstractA finite‐difference method is described for the numerical integration of the one‐dimensional shallow water equations over a sloping shelf that allows for a continuously moving shoreline. An application of the technique is made to the propagation of non‐breaking waves towards the shoreline. The results of the computation are compared with an evaluation based upon an exact analytical treatment of the non‐linear equations. Excellent agreement is found for both tsunami and tidal scale oscillations.
Surface tension driven flows in micro‐gravity conditions
Authors: Strani M. , Piva R. 
Published: August 2005

AbstractThe importance of convective flows generated by surface tension gradients, in comparison with the ones generated by other driving forces, has been investigated in connection with space technological applications involving fluid processes. A theoretical model of the boundary conditions at the interface, considered free and diffusive, has been derived in general tensor form to allow for the use of non orthogonal curvilinear co‐ordinates. For the study of flow fields contained in enclosures, these co‐ordinates are more suitable to fit all teh boundaries, in particular near the contact angle between the interface and the solid walls, thus giving more accurate numerical solutions.A computational procedure to solve the complete set of bulk and surface equations is proposed and applied to a simplified two dimensional flow in a rectangular enclosure with a temperature gradient between the lateral walls. The numerical results show the importance of considering the interface to be deformable and diffusive for an accurate evaluation of the convective flow in the fluid bulk.
The application of the finite‐element method to meteorological simulations—a review
Authors: Staniforth A. N. 
Published: August 2005

AbstractThe application of the finite‐element method to the simulation of meterological fluid flow problems is reviewed. Early studies were aimed primarily at demonstrating the viability of the method for one‐ and two‐dimensional flows, whereas more recent studies have been aimed at demonstrating the efficiency and viability of the method for more complex three‐dimensional simulations. There has also been a shift towards exploiting such models to better understand and predict the underlying meteorological phenomena, rather than restricting attention to the development of the algorithms.
On the finite‐element calculation of turbulent flow using the k‐ϵ model
Authors: Smith R. M. 
Published: August 2005

AbstractAlthough the finite‐element (FE) method has been successful in analysing complex laminar flows, a number of difficulties can arise when two‐equation turbulence models (e.g. the k‐ϵ model) are incorporated. This work describes a particular FE discretization of the k‐ϵ model and reports its performance in recirculating flow. Severe problems encountered in attempts to obtain convergence of the numerical scheme are isolated and analysed, and methods by which the problems can be overcome are suggested.Insight gained in this work has enabled a practical turbulent flow FE code to be constructed which is robust and efficient. This code is the subject of a further paper.
A practical method of two‐equation turbulence modelling using finite elements
Authors: Smith R. M. 
Published: August 2005

AbstractIncorporation of the k‐ϵ turbulence model into Galerkin finite‐element fluid‐flow codes (which, unlike upwind finite‐difference codes, have no artificial damping) can lead to severe iterative convergence difficulties. This paper introduces an alternative turbulence model (the q‐f model) and an associated finite‐element discretization method which are designed to overcome these problems. The new model forms the basis of a finite‐element fluid‐flow code which is robust and efficient. Furthermore, it is demonstrated on a practical example that the code can give good agreement with experiment on fairly coarse meshes.
A finite element method for the three‐dimensional non‐steady Navier‐Stokes equations
Authors: Mizukami A. , Tsuchiya M. 
Published: August 2005

AbstractThe algorithm for solving the three‐dimensional non‐steady Navier‐Stokes equations by the explicit forward Euler method is shown and the Galerkin finite element formulation is presented. As a numerical example, an entrace flow in a square duct is illustrated.
Numerical computations of critical flow over a weir
Authors: O'Carroll M. J. , Toro E. F. 
Published: August 2005

AbstractComputing critical flows in hydraulics involves three problems in one: the internal flow problem, the location of the free surface and the determination of the critical flow rate. The subject can involve such difficulties as non‐uniqueness, non‐existence, ill‐conditioning and catastrophes.This paper discusses the difficulties relating to computing critical flows over weirs. A new rapidly convergent method of determining the critical flow rate is presented and various results are shown using it with finite element discretization and with a new streamline shifting method. Numerical results are in good agreement with published data, both numerical and experimental.
Spline collocation approach to boundary value problems
Authors: Doctor H. D. , Bulsari A. B. , Kalthia N. L. 
Published: August 2005

AbstractA well‐known Stokes problem is discussed by a cubic spline collocation method. Two consecutive cubic splines are obtained for the problem. The results by this method are compared with those of an orthogonal collocation method. The selection of the length of the subintervals of the range of the boundary value problem is also justified. The results obtained by these two methods are compared with the analytic solution. The methods involve simple algebra, and hence the calculations do not require the help of a computer. Necessary error analysis has been carried out.
Some explicit triangular finite element schemes for the Euler equations
Authors: Angrand Françoise , Dervieux Alain 
Published: August 2005

AbstractSeveral explicit schemes are presented for triangular P0 and P1 finite elements. A first‐order accurate upwind P0 scheme is compared to a FLIC type method. A second‐order accurate Richtmyer scheme is constructed. Applications are given for the Euler system of conservation laws in the 2‐dimensional case.
On the interactions of surface waves with immersed structures
Authors: Bird H. W. K. , Shepherd R. 
Published: August 2005

AbstractThe fluid forces resulting from wave interaction with large submerged structures may be calculated using numerical procedures based on the solution of the associated boundary‐value problem. In this paper, the analysis of wave interaction with a fixed submerged object of arbitrary cross‐section and infinite length using a two‐dimensional boundary value formation based on linear diffraction theory is summarized. Subsequently, the application of the boundary element method to obtain a solution is presented. The numerical considerations are emphasized with particular reference to computational efficiency.Numerical results are presented in the form of dimensionless wave force plots for various structural shapes. In the case of a bottom‐seated half cylinder, for which there exists a closed‐form solution, comparisons are made between results generated using both boundary element and equivalent finite element approaches. In the case of a submerged cylinder, comparisons are made between boundary element derived values and experimental results. The boundary element results compare well with both the closed‐form solution and the experimental values.
Prediction of periodic boundary layers
Authors: Menendez A. N. , Ramaprian B. R. 
Published: August 2005

AbstractA relatively simple, yet efficient and accurate finite difference method is developed for the solution of the unsteady boundary layer equations for both laminar and turbulent flows. The numerical procedure is subjected to rigorous validation tests in the laminar case, comparing its predictions with exact analytical solutions, asymptotic solutions, and/or experimental results. Calculations of periodic laminar boundary layers are performed from low to very high oscillation frequencies, for small and large amplitudes, for zero as well as adverse time‐mean pressure gradients, and even in the presence of significant flow reversal. The numerical method is then applied to predict a relatively simple experimental periodic turbulent boundary layer, using two well‐known quasi‐steady closure models. The predictions are shown to be in good agreement with the measurements, thereby demonstrating the suitability of the present numerical scheme for handling periodic turbulent boundary layers. The method is thus a useful tool for the further development of turbulence models for more complex unsteady flows.
Diffraction of waves by semi‐infinite breakwater using finite and infinite elements
Authors: Bettess P. , Liang S. C. , Bettess J. A. 
Published: August 2005

AbstractA finite and infinite element model is derived to predict wave patterns around a semi‐infinite breakwater in water of constant depth. Both circular and square meshes of elements are used. The wave theory used is that of Berkhoff. The appropriate boundary conditions for finite and infinite boundaries are described. The singularity in the velocity at the breakwater tip is modelled effectively using the technique of Henshell and Shaw originally developed in elasticity. The results agree well with the analytical solution. In addition the problem of waves incident upon a semi‐infinite breakwater and parabolic shoal, where both diffraction and refraction are present, is solved. There is no analytical solution for this case. The combination of finite and infinite elements is found to be an effective and accurate technique for such problems.