Making an initial tetrahedral grid for complex geometry can be a tedious and time consuming task. This paper describes a novel procedure for generation of starting tetrahedral cells using hexahedral block topology. Hexahedral blocks are arranged around an aerodynamic body to form a flow domain. Each of the hexahedral blocks is then decomposed into six tetrahedral elements to obtain an initial t...

The refinement of tetrahedral meshes is a significant task in many numerical and discretizations methods. The computational aspects for implementing refinement of meshes with complex geometry need to be carefully considered in order to have real-time and optimal results. In this paper we study some computational aspects of a class of tetrahedral refinement algorithms. For local adaptive refinem...

In this article we consider the problem of finding Hamiltonian cycles on a tetrahedral mesh. A Hamiltonian cycle is a closed loop through a tetrahedral mesh that visits each tetrahedron exactly once. Using techniques of a novel discrete differential geometry of n-simplices, we could immediately obtain Hamiltonian cycles on a rhombic dodecahedronshaped tetrahedral mesh consisting of 24 tetrahedr...

The tetrahedral Cys2His2 Zn(II)-binding site in the de novo designed protein Z alpha 4 [Regan, L., & Clarke, N. D. (1990) Biochemistry 29, 10878] has been studied by independently mutating each of the metal-binding ligands to alanine. The contribution of each ligand to the geometry and affinity of metal binding has been characterized using Co(II), Zn(II), and Cd(II). The results indicate that a...

the reaction of [pphj, nos,] with cucl and kscn (1 :3:3) in acetone produces the yell-ow crystals of [pph,], [wos,(cuncs),]. the crystals are triclinic, space group p1(2), z=2, a=12.4823(7), b=12.9224(7), c=18.6395(10)?, ?=83.907(5), ?= 73.152(4), y= 65.194(4)'. the crystal structure was determined by single crystal xray diffraction methods (mo-k ?) and refined by least-squares calculation...

In this paper we investigate the problem of lossless geometry compression of irregular-grid volume data represented as a tetrahedral mesh. We propose a novel lossless compression technique that effectively predicts, models, and encodes geometry data for both steady-state (i.e., with only a single time step) and time-varying datasets. Our geometry coder is truly lossless and also does not need a...

A more automatic method for generation of tetrahedra and directional surface meshes are the two developments presented in this paper. Un-structured grids are generated for complex 3-D ge-ometries including multi-body domains. A combined octree-advancing front method is presented for the generation of the unstructured surface mesh as well as the tetrahedral volume mesh. The unique feature of thi...

This paper presents an approach for isogeometric analysis of 3D objects using rational Bézier tetrahedral elements. In this approach, both the geometry and the physical field are represented by trivariate splines in Bernstein Bézier form over the tetrahedrangulation of a 3D geometry. Given a NURBS represented geometry, either untrimmed or trimmed, we first convert it to a watertight geometry re...

When Ni2+ is surrounded by a ligand field due to cyanide ligands, a square planar geometry results. However, when Ni2+ forms a complex with chloride a tetrahedral geometry results. To determine the cause of this difference, hybrization, bonding, the molecular orbital picture, and symmetry will be considered using several techniques. Because the spacings between energy levels depend on factors s...