FY 1999 Laboratory Directed Research and Development annual report

Abstract

The images on the cover are computer simulations of the complex [Na]+ [edta]4-molecule (a tank complexing agent) using two three-dimensional codes, NWGrid and OSO. On the left is a volume mesh generated by NWGrid. The mesh fills the space between the molecular charge surface, which encloses the atoms, and a n exploded copy of that surface, slightly offset from the inner surface. There are 33 atoms in the molecule: 10 carbons (dark gray), two nitrogens (blue), one sodium (transparent cyan), eight oxygens (red), and 12 hydrogens (light gray). The volume is filled by a multiple scale-length mesh that is finest near the inner molecular charge surface, where field electric interactions a r e most complex, a n d coarsest a t the outer edge of the near-field extent.The O S 0 image on the right shows the same complex defined by each atom's characteristic van der Waals radius. The central sodium atom h a s been made transparent to reveal the atoms and structure behind it. The geometry-defining O S 0 file was used as input into NWGrid, which then generated the NWGrid surfaces and volume mesh.This work was performed by Janet Jones-Oliveira and Joseph Oliveira in their LDRD project, "Conservative Laws in Support of Reactive Transport." The project develops new algorithms for modeling hydrodynamics, subsurface transport, and molecular chemistry interactions. This work produces grids on which to compute complex geometries for modeling multiple computational and physical scales.NWGrid, the flagship code of the Applied Mathematics Group's "Center for Grid Generation and Unstructured Methods Development," is a three-dimensional, full-physics, first principles, timedomain, free-Lagrange code that was developed for parallel processing using unstructured grids. It is a library of user-callable tools that provide mesh generation, mesh optimization, and dynamic mesh maintenance in three dimensions. Regions within arbitrarily complicated geometries are defined as combinations of bounding surfaces where the surfaces are described analytically or as collections of points in space. O S 0 (developed by Los Alamos National Laboratory) is a geometry editor and volume renderer that defines geometries from which meshes are generated. The geometries may be defined interactively in terms of intersections and unions of surfaces or via input of Computer Aided Design output. DISCLAIMERPortions of this document may be illegible in electronic image products. Images are produced from the best available original document. PNNL-13203 UC-400 LDRD funding also allowed researchers at Pacific Northwest to make significant contributions in an effort to better understand global climate change and the transport and fate of subsurface contaminants. Today, we are using LDRD to explore the next frontier of environmental science and technology-improving knowledge on how environmental contaminants affect health.From LDRD-funded work on cell signaling, we now have programmatic funding to increase our understanding of the health effects of radiation exposure at ve...

Commonly Utilized Non Vascularised Bone Grafts in Maxillofacial Reconstruction

“…Apart from the common post-operative surgical complications like infection, wound dehiscence, pain, gait disturbance, and paraesthesia, proximal tibia fractures have seldomly been reported in the literature [2] [51]. In a retrospective study by Ana Lucia et al on 31 patients who underwent tibial bone harvesting, only 5 cases of minor complications were noted which all self-resolved within three weeks [52].…”