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A 1-Joule laser for a 16-fiber injection system (open access)

A 1-Joule laser for a 16-fiber injection system

A 1-J laser was designed to launch light down 16, multi-mode fibers (400-{micro}m-core dia.). A diffractive-optic splitter was designed in collaboration with Digital Optics Corporation (DOC), and was delivered by DOC. Using this splitter, the energy injected into each fiber varied <1%. The spatial profile out of each fiber was such that there were no ''hot spots,'' a flyer could successfully be launched and a PETN pellet could be initiated. Preliminary designs of the system were driven by system efficiency where a pristine TEM{sub 00} laser beam would be required. The laser is a master oscillator, power amplifier (MOPA) consisting of a 4-mm-dia. Nd:YLF rod in the stable, q-switched oscillator and a 9.5-mm-dia. Nd:YLF rod in the double-passed amplifier. Using a TEM{sub 00} oscillator beam resulted in excellent transmission efficiencies through the fibers at lower energies but proved to be quite unreliable at higher energies, causing premature fiber damage, flyer plate rupture, stimulated Raman scattering (SRS), and stimulated Brillouin scattering (SBS). Upon further investigation, it was found that both temporal and spatial beam formatting of the laser were required to successfully initiate the PETN. Results from the single-mode experiments, including fiber damage, SRS and SBS losses, will be presented. In …
Date: April 6, 2004
Creator: Honig, J.
System: The UNT Digital Library
2\beta + \gamma from B^0 to D^\mp K^0 \pi^\pm Decays at BaBar: aSimulation Study (open access)

2\beta + \gamma from B^0 to D^\mp K^0 \pi^\pm Decays at BaBar: aSimulation Study

The authors present the results of a simulation study to perform the extraction of 2{beta} + {gamma} from B{sup 0} {yields} D{sup {-+}}K{sup 0}{pi}{sup {+-}} decays through a time-dependent Dalitz analysis of BaBar data.
Date: April 16, 2007
Creator: Polci, Francesco; Schune, Marie-Helene; Stocchi, Achille & /Orsay, LAL
System: The UNT Digital Library
2-D and 3-D Elastic Modeling with Shared Seismic Models (open access)

2-D and 3-D Elastic Modeling with Shared Seismic Models

Several elastic models, both 2-D and 3-D, are being built for use in calculating synthetic elastic seismic data. The models will be made available to the research community, along with the synthetic data that are being calculated from them. These shared models have been proposed or contributed by participants in a collaborative industry, national laboratory, and university research project. The purpose of the modeling is to provide synthetic data to better understand elastic wave propagation and the effects of structural and stratigraphic complexities. The 2-D models are easier to design and change and synthetic calculations can be run relatively quickly in them. It will be possible to alter their layer properties and calculate time-lapse data sets from them. Field data will be available to accompany many of the 2-D models. 3-D models are more realistic, but more difficult to design and change. They also require considerably more computing resources to calculate synthetic data from them. A new 3-D model is being designed, and will be used for computing synthetic elastic data.
Date: April 30, 2002
Creator: House, L.; Marfurt, K. J.; Larsen, S. & Martin, G. S.
System: The UNT Digital Library
3-D elastic wave scattering by a layer containing vertical periodic fractures (open access)

3-D elastic wave scattering by a layer containing vertical periodic fractures

None
Date: April 30, 2002
Creator: Nakagawa, Seiji; Nihei, Kurt T.; Myer, Larry R. & Majer, Ernest L.
System: The UNT Digital Library
A 3-Dimensional discrete fracture network generator to examine fracture-matrix interaction using TOUGH2 (open access)

A 3-Dimensional discrete fracture network generator to examine fracture-matrix interaction using TOUGH2

Water fluxes in unsaturated, fractured rock involve the physical processes occurring at fracture-matrix interfaces within fracture networks. Modeling these water fluxes using a discrete fracture network model is a complicated effort. Existing preprocessors for TOUGH2 are not suitable to generate grids for fracture networks with various orientations and inclinations. There are several 3-D discrete-fracture-network simulators for flow and transport, but most of them do not capture fracture-matrix interaction. We have developed a new 3-D discrete-fracture-network mesh generator, FRACMESH, to provide TOUGH2 with information about the fracture network configuration and fracture-matrix interactions. FRACMESH transforms a discrete fracture network into a 3 dimensional uniform mesh, in which fractures are considered as elements with unique rock material properties and connected to surrounding matrix elements. Using FRACMESH, individual fractures may have uniform or random aperture distributions to consider heterogeneity. Fracture element volumes and interfacial areas are calculated from fracture geometry within individual elements. By using FRACMESH and TOUGH2, fractures with various inclinations and orientations, and fracture-matrix interaction, can be incorporated. In this paper, results of flow and transport simulations in a fractured rock block utilizing FRACMESH are presented.
Date: April 9, 2003
Creator: Ito, Kazumasa & Yongkoo, Seol
System: The UNT Digital Library
8-oxoguainine enhances bending of DNA that favors binding of glycosylases (open access)

8-oxoguainine enhances bending of DNA that favors binding of glycosylases

Molecular dynamics (MD) simulations were carried out on the DNA oligonucleotide GGGAACAACTAG:CTAGTTGTTCCC in its native form and with guanine in the central G19:C6 base pair replaced by 8-oxoguanine (8oxoG). A box of explicit water molecules was used for solvation and Na+ counterions were added to neutralize the system. The direction and magnitude of global bending were assessed by a technique used previously to analyze simulations of DNA containing a thymine dimer. The presence of 8oxoG did not greatly affect the magnitude of DNA bending; however, bending into the major groove was significantly more probable when 8oxoG replaced G19. Crystal structures of glycosylases bound to damaged-DNA substrates consistently show a sharp bend into the major groove at the damage site. We conclude that changes in bending dynamics that assist the formation of this kink are a part of the mechanism by which glycosylases of the base excision repair pathway recognize the presence of 8oxoG in DNA.
Date: April 23, 2003
Creator: Miller, John H.
System: The UNT Digital Library
12.6 keV Kr K-alpha X-ray Source For High Energy Density Physics Experiments (open access)

12.6 keV Kr K-alpha X-ray Source For High Energy Density Physics Experiments

A high contrast 12.6 keV Kr K{alpha} source has been demonstrated on the petawatt-class Titan laser facility. The contrast ratio (K{alpha} to continuum) is 65, with a competitive ultra short pulse laser to x-ray conversion efficiency of 10{sup -5}. Filtered shadowgraphy indicates that the Kr K{alpha} and K{beta} x-rays are emitted from a roughly 1 x 2 mm emission volume, making this source suitable for area backlighting and scattering. Spectral calculations indicate a typical bulk electron temperature of 50-70 eV (i.e. mean ionization state 13-16), based on the observed ratio of K{alpha} to K{beta}. Kr gas jets provide a debris-free high energy K{alpha} source for time-resolved diagnosis of dense matter.
Date: April 22, 2008
Creator: Kugland, N.; Constantin, C. G.; Niemann, C.; Neumayer, P.; Chung, H.; Doppner, T. et al.
System: The UNT Digital Library
13.2 nm Table-Top Inspection Microscope for Extreme Ultraviolet Lithography Mask Defect Characterization (open access)

13.2 nm Table-Top Inspection Microscope for Extreme Ultraviolet Lithography Mask Defect Characterization

We report on a reflection microscope that operates at 13.2-nm wavelength with a spatial resolution of 55{+-}3 nm. The microscope uses a table-top EUV laser to acquire images of photolithography masks in 20 seconds.
Date: April 7, 2009
Creator: Brizuela, F.; Wang, Y.; Brewer, C.; Pedaci, F.; Chao, W.; Anderson, E. et al.
System: The UNT Digital Library
50 years of excellence in science and engineering at the Savannah River Site (open access)

50 years of excellence in science and engineering at the Savannah River Site

This is a collection of papers including abstracts about the celebration of 50 years of excellence in science and engineering at the Savannah River Site. The Symposium Committee invited current and former employees to nominate the innovations to be recognized. Several selection panels of experts in various technical fields reviewed 190 nominations and selected the achievements included in this proceedings. Neither the Symposium Committee nor the selection panels claim that these accomplishments are the best of the best. Instead, they believe that they typify the outstanding quality of science and engineering at the Site during its first half-century.
Date: April 19, 2000
Creator: Phillips, A G
System: The UNT Digital Library
100% foundry compatible packaging and full wafer release and die separation technique for surface micromachined devices (open access)

100% foundry compatible packaging and full wafer release and die separation technique for surface micromachined devices

A completely foundry compatible chip-scale package for surface micromachines has been successfully demonstrated. A pyrex (Corning 7740) glass cover is placed over the released surface micromachined die and anodically bonded to a planarized polysilicon bonding ring. Electrical feedthroughs for the surface micromachine pass underneath the polysilicon sealing ring. The package has been found to be hermetic with a leak rate of less than 5 x 10{sup {minus}8} atm cm{sup {minus}3}/s. This technology has applications in the areas of hermetic encapsulation and wafer level release and die separation.
Date: April 6, 2000
Creator: Oliver, Andrew D. & Matzke, Carolyn M.
System: The UNT Digital Library
2005 Applied and Environmental Microbiology Gordon Conference July 24-29, 2005 (open access)

2005 Applied and Environmental Microbiology Gordon Conference July 24-29, 2005

This report is about Applied and Environmental Microbiology on Gordon Conference
Date: April 14, 2006
Creator: Kenneth Nealson, Nancy Ryan Gray
System: The UNT Digital Library
2005 DOE Hydrogen Program Review PresentationCOST AND PERFORMANCE ENHANCEMENTS FOR A PEM FUEL CELL TURBOCOMPRESSOR (open access)

2005 DOE Hydrogen Program Review PresentationCOST AND PERFORMANCE ENHANCEMENTS FOR A PEM FUEL CELL TURBOCOMPRESSOR

The objectives of the program during the past year was to complete Technical Objectives 2 and 3 and initiate Technical Objective 4 are described. To assist the Department of Energy in the development of a low cost, reliable and high performance air compressor/expander. Technical Objective 1: Perform a turbocompressor systems PEM fuel cell trade study to determine the enhanced turbocompressor approach. Technical Objective 2: Using the results from technical objective 1, an enhanced turbocompressor will be fabricated. The design may be modified to match the flow requirements of a selected fuel cell system developer. Technical Objective 3: Design a cost and performance enhanced compact motor and motor controller. Technical Objective 4: Turbocompressor/motor controller development.
Date: April 1, 2005
Creator: Gee, Mark K.
System: The UNT Digital Library
2006 Electrochemistry Gordon Research Conference - February 12-17-2006 (open access)

2006 Electrochemistry Gordon Research Conference - February 12-17-2006

This report is a descriptive journey of 2006 Electrochemistry Gordon Research Conference.
Date: April 3, 2007
Creator: Abruna, Hector D.
System: The UNT Digital Library
2006 Reversible Associations in Structural and Molecular Biology Conference-January 15-20, 2006 (open access)

2006 Reversible Associations in Structural and Molecular Biology Conference-January 15-20, 2006

Many biological processes are carried out through the formation of macromolecular complexes, ranging from the simplest conformational organization to the most sophisticated interactions among complexes themselves. Reversible associations generate specific local conformations, active site configurations, and subunit--subunit interfaces, and encompass larger scale quaternary rearrangements and dissociation events. Assembled complexes exhibit properties different from those of component parts, such that 'the whole is greater than the sum of the parts', resulting in biological functioning of the assembly. This Gordon Research Conference brings together researchers from what may appear to be disparate fields with the common focus of applying quantitative kinetic and thermodynamic analysis to reversible macromolecular interactions. This conference will include the following session topics: (1) Protein design in evolution and recognition; (2) Emerging technologies; (3) Single molecule mechanics; (4) Nucleic acid/protein recognition; (5) Lipid/protein recognition; (6) Protein switches and networks; (7) Advances in classic technologies; (8) Ligand/macromolecule complexes and drug design; and (9) Selected student oral presentations; all from the perspective of reversibly associating systems. A wide array of techniques are typically covered, from single molecule to computational methods, chromatography and analytical ultracentrifugation, spectroscopic dynamics and titration calorimetry. The quantitative analysis of assembled complexes demonstrates that these biologically important functions …
Date: April 10, 2007
Creator: Gray, Gary Ackers Nancy Ryan
System: The UNT Digital Library
2007 Microbial Population Biology (July 22-26, 2007) (open access)

2007 Microbial Population Biology (July 22-26, 2007)

Microbial Population Biology covers a diverse range of cutting edge issues in the microbial sciences and beyond. Firmly founded in evolutionary biology and with a strongly integrative approach, past meetings have covered topics ranging from the dynamics and genetics of adaptation to the evolution of mutation rate, community ecology, evolutionary genomics, altruism, and epidemiology. This meeting is never dull: some of the most significant and contentious issues in biology have been thrashed out here. We anticipate the 2007 meeting being no exception. The final form of the 2007 meeting is yet to be decided, but the following topics are likely to be included: evolutionary emergence of infectious disease and antibiotic resistance, genetic architecture and implications for the evolution of microbial populations, ageing in bacteria, biogeography, evolution of symbioses, the role of microbes in ecosystem function, and ecological genomics.
Date: April 1, 2008
Creator: Dean, Anthony M. & Gray, Nancy Ryan
System: The UNT Digital Library
THE 2ND ERHIC WORKSHOP. (open access)

THE 2ND ERHIC WORKSHOP.

None
Date: April 4, 2000
Creator: Venugopalan, R. & Al, Et
System: The UNT Digital Library
A 3D Frictional Segment-to-Segment Contact Method for Large Deformations and Quadratic Elements (open access)

A 3D Frictional Segment-to-Segment Contact Method for Large Deformations and Quadratic Elements

Node-on-segment contact is the most common form of contact used today but has many deficiencies ranging from potential locking to non-smooth behavior with large sliding. Furthermore, node-on-segment approaches are not at all applicable to higher order discretizations (e.g. quadratic elements). In a previous work, [3, 4] we developed a segment-to-segment contact approach for eight node hexahedral elements based on the mortar method that was applicable to large deformation mechanics. The approach proved extremely robust since it eliminated the over-constraint that caused 'locking' and provided smooth force variations in large sliding. Here, we extend this previous approach to treat frictional contact problems. In addition, the method is extended to 3D quadratic tetrahedrals and hexahedrals. The proposed approach is then applied to several challenging frictional contact problems that demonstrate its effectiveness.
Date: April 1, 2004
Creator: Puso, M; Laursen, T & Solberg, J
System: The UNT Digital Library
3D Magnetotelluic characterization of the Coso GeothermalField (open access)

3D Magnetotelluic characterization of the Coso GeothermalField

Electrical resistivity may contribute to progress inunderstanding geothermal systems by imaging the geometry, bounds andcontrolling structures in existing production, and thereby perhapssuggesting new areas for field expansion. To these ends, a dense grid ofmagnetotelluric (MT) stations plus a single line of contiguous bipolearray profiling has been acquired over the east flank of the Cosogeothermal system. Acquiring good quality MT data in producing geothermalsystems is a challenge due to production related electromagnetic (EM)noise and, in the case of Coso, due to proximity of a regional DCintertie power transmission line. To achieve good results, a remotereference completely outside the influence of the dominant source of EMnoise must be established. Experimental results so far indicate thatemplacing a reference site in Amargosa Valley, NV, 65 miles from the DCintertie, isstill insufficient for noise cancellation much of the time.Even though the DC line EM fields are planar at this distance, theyremain coherent with the nonplanar fields in the Coso area hence remotereferencing produces incorrect responses. We have successfully unwrappedand applied MT times series from the permanent observatory at Parkfield,CA, and these appear adequate to suppress the interference of thecultural EM noise. The efficacy of this observatory is confirmed bycomparison to stations taken using an ultra-distant …
Date: April 23, 2007
Creator: Newman, Gregory A.; Hoversten, G. Michael; Wannamaker, Philip E. & Gasperikova, Erika
System: The UNT Digital Library
3w Transmitted Beam Diagnostic at the Omega Laser Facility (open access)

3w Transmitted Beam Diagnostic at the Omega Laser Facility

A 3{omega} transmitted beam diagnostic has been commissioned on the Omega Laser at the Laboratory for Laser Energetics, University of Rochester [Soures et.al., Laser Part. Beams 11 (1993)]. Transmitted light from one beam is collected by a large focusing mirror and directed onto a diagnostic platform. The near field of the transmitted light is imaged; the system collects information from twice the original f-cone of the beam. Two gated optical cameras capture the near field image of the transmitted light. Thirteen spatial positions around the measurement region are temporally resolved using fast photodiodes to allow a measure of the beam spray evolution. The Forward stimulated Raman scattering and forward simulated Brillion scattering are spectrally and temporally resolved at 5 independent locations within twice the original f-cone. The total transmitted energy is measured in two spectral bands ({delta}{lambda} < 400 nm and {delta}{lambda} > 400 nm).
Date: April 24, 2006
Creator: Froula, D. H.; Rekow, V.; Sorce, C.; Piston, K.; Knight, R.; Alvarez, S. et al.
System: The UNT Digital Library
6th Annual Systems Biology Symposium: Systems Biology and the Environment (open access)

6th Annual Systems Biology Symposium: Systems Biology and the Environment

Systems biology recognizes the complex multi-scale organization of biological systems, from molecules to ecosystems. The International Symposium on Systems Biology is an annual two-day event gathering the most influential researchers transforming biology into an integrative discipline investigating complex systems. In recognition of the fundamental similarity between the scientific problems addressed in environmental science and systems biology studies at the molecular, cellular, and organismal levels, the 2007 Symposium featured global leaders in “Systems Biology and the Environment.” The objective of the 2007 “Systems Biology and the Environment” International Symposium was to stimulate interdisciplinary thinking and research that spans systems biology and environmental science. This Symposium was well aligned with the DOE’s Genomics:GTL program efforts to achieve scientific objectives for each of the three DOE missions: • Develop biofuels as a major secure energy source for this century, • Develop biological solutions for intractable environmental problems, and • Understand biosystems’ climate impacts and assess sequestration strategies Our scientific program highlighted world-class research exemplifying these priorities. The Symposium featured 45 minute lectures from 12 researchers including: Penny/Sallie Chisholm of MIT gave the keynote address “Tiny Cells, Global Impact: What Prochlorococcus Can Teach Us About Systems Biology”, plus Jim Fredrickson of PNNL, Nitin Baliga …
Date: April 1, 2007
Creator: Galitski, Timothy, P.
System: The UNT Digital Library
7th Annual Systems Biology Symposium: Systems Biology and Engineering (open access)

7th Annual Systems Biology Symposium: Systems Biology and Engineering

Systems biology recognizes the complex multi-scale organization of biological systems, from molecules to ecosystems. The International Symposium on Systems Biology has been hosted by the Institute for Systems Biology in Seattle, Washington, since 2002. The annual two-day event gathers the most influential researchers transforming biology into an integrative discipline investingating complex systems. Engineering and application of new technology is a central element of systems biology. Genome-scale, or very small-scale, biological questions drive the enigneering of new technologies, which enable new modes of experimentation and computational analysis, leading to new biological insights and questions. Concepts and analytical methods in engineering are now finding direct applications in biology. Therefore, the 2008 Symposium, funded in partnership with the Department of Energy, featured global leaders in "Systems Biology and Engineering."
Date: April 1, 2008
Creator: Galitski, Timothy P.
System: The UNT Digital Library
AB INITIO AND CALPHAD THERMODYNAMICS OF MATERIALS (open access)

AB INITIO AND CALPHAD THERMODYNAMICS OF MATERIALS

Ab initio electronic structure methods can supplement CALPHAD in two major ways for subsequent applications to stability in complex alloys. The first one is rather immediate and concerns the direct input of ab initio energetics in CALPHAD databases. The other way, more involved, is the assessment of ab initio thermodynamics {acute a} la CALPHAD. It will be shown how these results can be used within CALPHAD to predict the equilibrium properties of multi-component alloys.
Date: April 14, 2004
Creator: Turchi, P A
System: The UNT Digital Library
Ab initio study of Al(III) adsorption on stepped {100} surfaces of KDP crystals (open access)

Ab initio study of Al(III) adsorption on stepped {100} surfaces of KDP crystals

Crystals of potassium dihydrogen phosphate (KH{sub 2}PO{sub 4}, KDP) are grown in large scale for use as nonlinear material in laser components. Traces of trivalent metal impurities are often added to the supernatant to achieve habit control during crystal growth, selectively inhibiting the growth of the {l_brace}100{r_brace} face. Model systems representing AlPO{sub 4}-doped KDP {l_brace}100{r_brace} stepped surfaces are prepared and studied using ab initio quantum methods. Results of Hartree-Fock partial optimizations are presented, including estimated energies of ion pair binding to the steps. We find that the PO{sub 4}{sup 3-} ion takes a position not unlike that of a standard phosphate in the crystal lattice, while the aluminum atom is displaced far from a K{sup +} ion position to establish coordinations with the PO{sub 4}{sup 3-} ion and to bind with another lattice-bound phosphate. Our optimized structures suggest that it is the formation of a fourth coordination of Al(III) to a third phosphate ion from solution, or perhaps from a nearby position in the lattice, that disrupts further deposition, pinning the steps.
Date: April 1, 2004
Creator: Salter, E A; Wierzbicki, A & Land, T A
System: The UNT Digital Library
Ab initio study of low-energy electron collisions withtertafluoroethene, C2F4 (open access)

Ab initio study of low-energy electron collisions withtertafluoroethene, C2F4

We report the results of variational calculations of elastic electron scattering by tetrafluoroethene, C{sub 2}F{sub 4}, with incident electron energies ranging from 0.5 to 20 eV, using the complex Kohn method and effective core potentials. These are the first fully calculations to reproduce experimental angular differential cross sections at energies below 10 eV. Low-energy electron scattering by C{sub 2}F{sub 4} is sensitive to the inclusion of electronic correlation and target-distortion effects. We therefore present results that describe the dynamic polarization of the target by the incident electron. The calculated cross sections are compared with recent experimental measurements.
Date: April 26, 2004
Creator: Trevisan, C. S.; Orel, A. E. & Rescigno, Thomas N.
System: The UNT Digital Library