13,066 research outputs found
Efficient Compilation of a Class of Variational Forms
We investigate the compilation of general multilinear variational forms over
affines simplices and prove a representation theorem for the representation of
the element tensor (element stiffness matrix) as the contraction of a constant
reference tensor and a geometry tensor that accounts for geometry and variable
coefficients. Based on this representation theorem, we design an algorithm for
efficient pretabulation of the reference tensor. The new algorithm has been
implemented in the FEniCS Form Compiler (FFC) and improves on a previous
loop-based implementation by several orders of magnitude, thus shortening
compile-times and development cycles for users of FFC.Comment: ACM Transactions on Mathematical Software 33(3), 20 pages (2007
A general approach to transforming finite elements
The use of a reference element on which a finite element basis is constructed
once and mapped to each cell in a mesh greatly expedites the structure and
efficiency of finite element codes. However, many famous finite elements such
as Hermite, Morley, Argyris, and Bell, do not possess the kind of equivalence
needed to work with a reference element in the standard way. This paper gives a
generalizated approach to mapping bases for such finite elements by means of
studying relationships between the finite element nodes under push-forward.Comment: 28 page
Promotion of dropwise condensation of ethyl alcohol, methyl alcohol, and acetone by polytetrafluoroethylene
Coating condensing surfaces with thin layer of nonpolar Teflon results in dropwise condensation of polar organic vapor. Greater heat transfer coefficients are produced increasing effectiveness of condensing system. Investigation shows that vapors with strong dipole moment tend to condense dropwise
Preliminary investigation of effects of exposure to sulfur hexafluoride on tensile and yield strengths of aluminum and steel
Effects of sulfur hexafluoride on tensile and yield strengths of aluminum and steel with application to exhaust gases from rocket engine
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