A Compact High Gradient Pulsed Magnetic Quadpole (open access)

A Compact High Gradient Pulsed Magnetic Quadpole

A design for a high gradient, low inductance pulsed quadrupole magnet is presented. The magnet is a circular current dominated design with a circular iron return yoke. Conductor angles are determined by a method of direct multipole elimination which theoretically eliminates the first four higher order multipole field components. Coils are fabricated from solid round film-insulated conductor, wound as a single layer ''non-spiral bedstead'' coil having a diagonal leadout entirely within one upturned end. The coils are wound and stretched straight in a special winder, then bent in simple fixtures to form the upturned ends.
Date: July 5, 2005
Creator: Shuman, D.; Faltens, A.; Kajiyama, Y.; Kireeff-Covo, M. & Seidl, P.
System: The UNT Digital Library
Atomistic Modeling of Wave Propagation in Nanocrystals (open access)

Atomistic Modeling of Wave Propagation in Nanocrystals

We present non-equilibrium molecular dynamics (MD) simulations of wave propagation in nanocrystals. We find that the width of the traveling wave front increases with grain size, d, as d{sup 1/2}. This width also decreases with the pressure behind the front. We extrapolate our results to micro-crystals and obtain reasonable agreement with experimental data. In addition, our extrapolation agrees with models that only take into account the various velocities of propagation along different crystalline orientations, without including grain boundary effects. Our results indicate that, even at the nanoscale, the role of grain boundaries as scattering centers or as sources of plasticity does not increase significantly the width of the traveling wave.
Date: July 5, 2005
Creator: Bringa, E; Caro, A; Victoria, M & Park, N
System: The UNT Digital Library
SNP-VISTA: An Interactive SNPs Visualization Tool (open access)

SNP-VISTA: An Interactive SNPs Visualization Tool

Recent advances in sequencing technologies promise better diagnostics for many diseases as well as better understanding of evolution of microbial populations. Single Nucleotide Polymorphisms(SNPs) are established genetic markers that aid in the identification of loci affecting quantitative traits and/or disease in a wide variety of eukaryotic species. With today's technological capabilities, it is possible to re-sequence a large set of appropriate candidate genes in individuals with a given disease and then screen for causative mutations.In addition, SNPs have been used extensively in efforts to study the evolution of microbial populations, and the recent application of random shotgun sequencing to environmental samples makes possible more extensive SNP analysis of co-occurring and co-evolving microbial populations. The program is available at http://genome.lbl.gov/vista/snpvista.
Date: July 5, 2005
Creator: Shah, Nameeta; Teplitsky, Michael V.; Pennacchio, Len A.; Hugenholtz, Philip; Hamann, Bernd & Dubchak, Inna L.
System: The UNT Digital Library
Downgrade of the Savannah River Sites FB-Line (open access)

Downgrade of the Savannah River Sites FB-Line

This paper will discuss the Safeguards & Security (S&S) activities that resulted in the downgrade of the Savannah River Site's FB-Line (FBL) from a Category I Material Balance Area (MBA) in a Material Access Area (MAA) to a Category IV MBA in a Property Protection Area (PPA). The Safeguards activities included measurement of final product items, transferal of nuclear material to other Savannah River Site (SRS) facilities, discard of excess nuclear material items, and final measurements of holdup material. The Security activities included relocation and destruction of classified documents and repositories, decertification of a classified computer, access control changes, updates to planning documents, deactivation and removal of security systems, Human Reliability Program (HRP) removals, and information security training for personnel that will remain in the FBL PPA.
Date: July 5, 2005
Creator: SADOWSKI, ED; YOURCHAK, RANDY; MARJI, PRETZELLO; MIXON, BONNIE & LYNN, ROBBIE
System: The UNT Digital Library
A Silicon-Based, Sequential Coat-and-Etch Process to Fabricate Nearly Perfect Substrate Surfaces (open access)

A Silicon-Based, Sequential Coat-and-Etch Process to Fabricate Nearly Perfect Substrate Surfaces

For many thin-film applications substrate imperfections such as particles, pits, scratches, and general roughness, can nucleate film defects which can severely detract from the coating's performance. Previously we developed a coat-and-etch process, termed the ion beam thin film planarization process, to planarize substrate particles up to {approx} 70 nm in diameter. The process relied on normal incidence etching; however, such a process induces defects nucleated by substrate pits to grow much larger. We have since developed a coat-and-etch process to planarize {approx}70 nm deep by 70 nm wide substrate pits; it relies on etching at an off-normal incidence angle, i.e., an angle of {approx} 70{sup o} from the substrate normal. However, a disadvantage of this pit smoothing process is that it induces defects nucleated by substrate particles to grow larger. Combining elements from both processes we have been able to develop a silicon-based, coat-and-etch process to successfully planarize {approx}70 nm substrate particles and pits simultaneously to at or below 1 nm in height; this value is important for applications such as extreme ultraviolet lithography (EUVL) masks. The coat-and-etch process has an added ability to significantly reduce high-spatial frequency roughness, rendering a nearly perfect substrate surface.
Date: July 5, 2005
Creator: Mirkarimi, P. B.; Spiller, E.; Baker, S. L.; Stearns, D. G.; Robinson, J. C.; Olynick, D. L. et al.
System: The UNT Digital Library