Boundary elements and symmetry

Hartmann, Friedel; Katz, Casimir; Protopsaltis, B.

doi:10.1007/bf00537652

Cited by 70 publications

(18 citation statements)

References 5 publications

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“…The adhesion of selected polymers (polysaccharides) on mucin was in the order S-hya> gellan> S-Alg > dextran. Miosis testing of gellan containing formulations in rabbits shows a possible reduction of drug concentration from 2% to 0.5% obtaining the same bioavailability 26 .…”

Section: +mentioning

confidence: 90%

Untitled

2012

IJPSR

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Topical administration of a drug in the conjunctival cul-de-sac is the treatment of choice for diseases of the anterior segment of eye. Development of ophthalmic drug delivery systems has always been challenging because of the drawbacks with this route, like non-productive absorption, drainage, induced lacrimation, tear turn over, impermeability of drugs to cornea. New approaches have been investigated for delivery of drugs to the eye by means of polymeric delivery of ophthalmic drugs to the pre-and intra ocular tissues, have been attempted to increase the bioavailability and the duration of therapeutic action of ocular drug. Certain new approaches to increase the ocular bioavailability, duration of the drug action and to reduce the undesirable side effects are by using drug carriers that regulate pre-corneal drug loss and improve the corneal contact time. Many of these systems prolong ocular bioavailability but do not control drug penetration through the cornea. Consequently, the drug concentration at the site of action might remain inadequate. Therefore, it is necessary to develop safer, efficacious and more acceptable ocular therapeutic system. The ocular bioavailability of the drugs can be improved by prolonging their residence time in the cul-de-sac and by increasing their corneal permeability. There are various new dosage forms like in-situ gel, collagen shield, etc.

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Section: +mentioning

confidence: 90%

Untitled

2012

IJPSR

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“…Maier et al [5] presented an elastodynamic Galerkin formulation employing multi-zone approach. Further treatments in elasticity has been given by Polizzotto [6] and Hartman et al [7]. In elastoplastic analysis, Galerkin approaches have been described by Maier and Polizzotto [8] and Polizzotto and Zito [9].…”

Section: Background Of the Symmetric Galerkin Methodsmentioning

confidence: 98%

Symmetric coupling of multi-zone curved Galerkin boundary elements with finite elements in elasticity

Ganguly

Layton

Balakrishna

2000

Int. J. Numer. Meth. Engng.

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SUMMARYThe coupling of Finite Element Method (FEM) with a Boundary Element Method (BEM) is a desirable result that exploits the advantages of each. This paper examines the e$cient symmetric coupling of a Symmetric Galerkin Multi-zone Curved Boundary Element Analysis method with a Finite Element Method for 2-D elastic problems. Existing collocation based multi-zone boundary element methods are not symmetric. Thus, when they are coupled with FEM, it is very di$cult to achieve symmetry, increasing the computational work to solve the problem. This paper uses a fully Symmetric curved Multi-zone Galerkin Boundary Element Approach that is coupled to an FEM in a completely symmetric fashion. The symmetry is achieved by symmetrically converting the boundary zones into equivalent ¯o "nite elements', that are symmetric, so that symmetry in the coupling is retained. This computationally e$cient and fast approach can be used to solve a wide range of problems, although only 2-D elastic problems are shown. Three elasticity problems, including one from the FEM-BEM literature that explore the e$cacy of the approach are presented.

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“…The formulation possesses the attractive feature of producing a symmetric coefficient matrix [1][2][3] and, in addition, the Galerkin approximation allows standard continuous C 0 elements to be used for evaluation of hypersingular integrals. These properties make the SGBEM suitable for coupling with the popular finite element method (FEM) [4].…”

Section: Introductionmentioning

confidence: 99%

On hypersingular surface integrals in the symmetric Galerkin boundary element method: application to heat conduction in exponentially graded materials

Sutradhar

Paulino

Gray

2004

Int. J. Numer. Meth. Engng

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SUMMARYA symmetric Galerkin formulation and implementation for heat conduction in a three-dimensional functionally graded material is presented. The Green's function of the graded problem, in which the thermal conductivity varies exponentially in one co-ordinate, is used to develop a boundary-only formulation without any domain discretization. The main task is the evaluation of hypersingular and singular integrals, which is carried out using a direct 'limit to the boundary' approach. However, due to complexity of the Green's function for graded materials, the usual direct limit procedures have to be modified, incorporating Taylor expansions to obtain expressions that can be integrated analytically. Several test examples are provided to verify the numerical implementation. The results of test calculations are in good agreement with exact solutions and corresponding finite element method simulations.

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Boundary elements and symmetry

Cited by 70 publications

References 5 publications

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Symmetric coupling of multi-zone curved Galerkin boundary elements with finite elements in elasticity

On hypersingular surface integrals in the symmetric Galerkin boundary element method: application to heat conduction in exponentially graded materials

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