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Collapsing Radiative Shocks in Argon Gas on the Omega Laser
A number of astrophysical systems involve radiative shocks that collapse spatially in response to energy lost through radiation. Supernova remnants are an example of systems that cool enough to radiatively collapse. This is believed to produce thin, dense shells that are Vishniac unstable. This type of instability may be responsible for the convoluted structure of supernova remnants such as the Cygnus Loop. We are conducting experiments on the Omega laser intended to produce such collapsing shocks and to study their evolution. The experiments use the laser to accelerate a thin slab of driving material (beryllium) through 1.1 ATM of argon gas ({approx}2 mg/cc) at {approx}100 km/sec. The simulations also predict that the dense layer will be pushed ahead of the dense beryllium by the leading edge of the expansion of this material. The experiment is diagnosed in two ways. X-ray radiography has detected the presence of the dense shocked layer. These data indicate that the shock velocity is {approx}100 km/s. A unique, side-on application of the VISAR (Velocity Interferometer System for Any Reflector) technique is used to detect frequency shifts from ionization and any reflections from the edge of the dense shocked layer.
Date:
November 1, 2003
Creator:
Reighard, A. B.; Drake, R. P.; Dannenberg, K.; Perry, T. S.; Robey, H. A.; Remington, B. A. et al.
Object Type:
Article
System:
The UNT Digital Library
Conceptual Design of a Very High Temperature Pebble-Bed Reactor
Efficient electricity and hydrogen production distinguish the Very High Temperature Reactor as the leading Generation IV advanced concept. This graphite-moderated, helium-cooled reactor achieves a requisite high outlet temperature while retaining the passive safety and proliferation resistance required of Generation IV designs. Furthermore, a recirculating pebble-bed VHTR can operate with minimal excess reactivity to yield improved fuel economy and superior resistance to ingress events. Using the PEBBED code developed at the INEEL, conceptual designs of 300 megawatt and 600 megawatt (thermal) Very High Temperature Pebble-Bed Reactors have been developed. The fuel requirements of these compare favorably to the South African PBMR. Passive safety is confirmed with the MELCOR accident analysis code.
Date:
November 1, 2003
Creator:
Gougar, Hans D.; Ougouag, A. M.; Moore, Richard M. & Terry, W. K.
Object Type:
Article
System:
The UNT Digital Library
Consumptive Water Use for U.S. Power Production: Preprint
Evaporative cooling systems have been criticized for their water use and acclaimed for their low energy consumption, especially when compared to typical cooling systems. In order to determine the overall effectiveness of cooling systems, both water and energy need to be considered; however, there must be a metric to compare the amount of energy used at the site to the amount of water used at the power plant. A study of power plants and their respective water consumption was completed to effectively analyze evaporative cooling systems.
Date:
November 1, 2003
Creator:
Torcellini, P.; Long, N. & Judkoff, R.
Object Type:
Article
System:
The UNT Digital Library
[Couple Preparing Altar]
Photograph of two individuals preparing an altar during a Day of the Dead celebration hosted by the Mexic-Arte Museum in Austin, Texas. They adjust a piece of cloth laid on the altar. A framed painting rests on the altar. A yellow archway and cross are affixed to the wall behind it.
Date:
November 1, 2003
Creator:
Mexic-Arte Museum (Austin, Tex.)
Object Type:
Photograph
System:
The Portal to Texas History
Covert air vehicle 2003 LDRD final report.
This report describes the technical work carried out under a 2003 Laboratory Directed Research and Development project to develop a covert air vehicle. A mesoscale air vehicle that mimics a bird offers exceptional mobility and the possibility of remaining undetected during flight. Although some such vehicles exist, they are lacking in key areas: unassisted landing and launching, true mimicry of bird flight to remain covert, and a flapping flight time of any real duration. Current mainstream technology does not have the energy or power density necessary to achieve bird like flight for any meaningful length of time; however, Sandia has unique combustion powered linear actuators with the unprecedented high energy and power density needed for bird like flight. The small-scale, high-pressure valves and small-scale ignition to make this work have been developed at Sandia. We will study the feasibility of using this to achieve vehicle takeoff and wing flapping for sustained flight. This type of vehicle has broad applications for reconnaissance and communications networks, and could prove invaluable for military and intelligence operations throughout the world. Initial tests were conducted on scaled versions of the combustion-powered linear actuator. The tests results showed that heat transfer and friction effects dominate the …
Date:
November 1, 2003
Creator:
Spletzer, Barry Louis; Callow, Diane Schafer; Salton, Jonathan Robert & Fischer, Gary John
Object Type:
Report
System:
The UNT Digital Library
The Cross Timbers Gazette (Flower Mound, Tex.), Vol. 29, No. 11, Ed. 1, November 2003
Monthly newspaper from Flower Mound, Texas that includes news and information for communities in southern Denton County along with advertising.
Date:
November 2003
Creator:
Johnson, LaRue
Object Type:
Newspaper
System:
The Portal to Texas History
[Dallas National Bank Schedule of Fees]
Dallas National Bank schedule of fees on November 1, 2003 listing miscellaneous fees, deposit box charges, and ATM services.
Date:
November 1, 2003
Creator:
unknown
Object Type:
Text
System:
The UNT Digital Library
[Dancers at Día de los Muertos Parade]
Photograph of individuals dancing at a parade hosted by the Mexic-Arte Museum in honor of Día de los Muertos, or Day of the Dead. A woman faces away from the camera. She wears a yellow dress with ribbonwork tiers and lace. A young girl dances on the right. She wears a similar style dress that is blue in color. The photograph was taken at nighttime in downtown Austin, Texas.
Date:
November 1, 2003
Creator:
Mexic-Arte Museum (Austin, Tex.)
Object Type:
Photograph
System:
The Portal to Texas History
The dependence of natural graphite anode performance on electrode density
The effect of electrode density for lithium intercalation and irreversible capacity loss on the natural graphite anode in lithium ion batteries was studied by electrochemical methods. Both the first-cycle reversible and irreversible capacities of the natural graphite anode decreased with an increase in the anode density though compression. The reduction in reversible capacity was attributed to a reduction in the chemical diffusion coefficient for lithium though partially agglomerated particles with a larger stress. For the natural graphite in this study the potentials for Li (de)insertion shifted between the first and second formation cycles and the extent of this shift was dependent on electrode density. The relation between this peak shift and the irreversible capacity loss are probably both due to the decrease in graphite surface area with compression.
Date:
November 1, 2003
Creator:
Shim, Joongpyo & Striebel, Kathryn A.
Object Type:
Article
System:
The UNT Digital Library
Design, Construction and Operation Of A High Pressure Flow Loop Reactor For Carbon Sequestration
The Department of Energy’s Albany Research Center has been exploring the possibility of direct mineral carbonation as a means of sequestering carbon dioxide. As part of this research, a three-phase flow through reactor capable of operating at 200°C and 2500 psia was built. The reactor is a plug flow reactor with continuous and complete recycle. The results from this reactor may be used to design a larger and truly continuous flow reactor. This paper describes the design, construction and operation of this reactor. The extent of reaction, pressure drop across the pump and static mixers were measured at various test conditions. The extent of reaction was then compared to the results achievable in an autoclave.
Date:
November 1, 2003
Creator:
Gerdemann, Stephen J., Penner, Larry R.
Object Type:
Presentation
System:
The UNT Digital Library
Design of a Production Process to Enhance Optical Performance of 3(omega) Optics
Using the Phoenix pre-production conditioning facility we have shown that raster scanning of 3{omega} optics using a XeF excimer laser and mitigation of the resultant damage sites with a CO{sub 2} laser can enhance their optical damage resistance. Several large-scale (43 cm x 43 cm) optics have been processed in this facility. A production facility capable of processing several large optics a week has been designed based on our experience in the pre-production facility. The facility will be equipped with UV conditioning lasers--351-nm XeF excimer lasers operating at 100 Hz and 23 ns. The facility will also include a CO{sub 2} laser for damage mitigation, an optics stage for raster scanning large-scale optics, a damage mapping system (DMS) that images large-scale optics and can detect damage sites or precursors as small as {approx} 15 {micro}m, and two microscopes to image damage sites with {approx} 5 {micro}m resolution. The optics will be handled in a class 100 clean room, within the facility that will be maintained at class 1000.
Date:
November 1, 2003
Creator:
Prasad, R R; Bruere, J R; Halpin, J; Lucero, P; Mills, S; Bernacil, M et al.
Object Type:
Article
System:
The UNT Digital Library
Design of Controls to Attenuate Loads in the Controls Advanced Research Turbine: Preprint
Designing wind turbines to maximize energy production and increase fatigue life is a major goal of the wind industry. To achieve this goal, we must design wind turbines to extract maximum energy and reduce component and system loads. This paper applies modern state-space control design methods to a two-bladed teetering-hub upwind machine located at the National Wind Technology Center*. The design objective is to regulate turbine speed in region 3 (above rated wind speed) and enhance damping in several low-damped flexible modes of the turbine. The controls approach is based on the Disturbance Accommodating Control (DAC) method and provides accountability for wind-speed disturbances. First, controls are designed using the single control input rotor collective pitch to stabilize the first drive-train torsion as well as the tower first fore-aft bending modes. Generator torque is then incorporated as an additional control input. This reduces some of the demand placed on the rotor collective pitch control system and enhances first drive train torsion mode damping. Individual blade pitch control is then used to attenuate wind disturbances having spatial variation over the rotor and effectively reduces blade flap deflections caused by wind shear.
Date:
November 1, 2003
Creator:
Wright, A. D. & Balas, M. J.
Object Type:
Article
System:
The UNT Digital Library
Detection and Location of Damage on Pipelines
The INEEL has developed and successfully tested a real-time pipeline damage detection and location system. This system uses porous metal resistive traces applied to the pipe to detect and locate damage. The porous metal resistive traces are sprayed along the length of a pipeline. The unique nature and arrangement of the traces allows locating the damage in real time along miles of pipe. This system allows pipeline operators to detect damage when and where it is occurring, and the decision to shut down a transmission pipeline can be made with actual real-time data, instead of conservative estimates from visual inspection above the area.
Date:
November 1, 2003
Creator:
Moore, Karen A.; Carrington, Robert & Richardson, John
Object Type:
Article
System:
The UNT Digital Library
Development of a Process Model for CO(2) Laser Mitigation of Damage Growth in Fused Silica
A numerical model of CO{sub 2} laser mitigation of damage growth in fused silica has been constructed that accounts for laser energy absorption, heat conduction, radiation transport, evaporation of fused silica and thermally induced stresses. This model will be used to understand scaling issues and effects of pulse and beam shapes on material removal, temperatures reached and stresses generated. Initial calculations show good agreement of simulated and measured material removal. The model has also been applied to LG-770 glass as a prototype red blocker material.
Date:
November 1, 2003
Creator:
Feit, M D; Rubenchik, A M; Boley, C & Rotter, M D
Object Type:
Article
System:
The UNT Digital Library
DEVELOPMENT OF AN ADVANCED APPROACH FOR NEXT GENERATION, HIGH RESOLUTION, INTEGRATED RESERVOIR CHARACTERIZATION
During this reporting period all preliminary tasks were completed (such as the creation of a flexible project database) and construction of the actual broadband transform function was begun. Analysis of intermediate results performed during the reporting period has proven that the neural networks being used can accurately predict data elements using surface seismic or crosswell seismic data and attributes as input.
Date:
November 1, 2003
Creator:
Reeves, Scott R. & Steen, Jack W.
Object Type:
Report
System:
The UNT Digital Library
Development of detection techniques and diagnostics for airborne carbon nanoparticles.
We have recorded time-resolved LII signals from a laminar ethylene diffusion flame over a wide range of laser fluences at 532 nm. We have performed these experiments using an injection-seeded NdYAG laser with a pulse duration of 7 ns. The beam was spatially filtered and imaged into the flame to provide a homogeneous spatial profile. These data were used to aid in the development of a model, which will be used to test the validity of the LII technique under varying environmental conditions. The new model describes the heating of soot particles during the laser pulse and the subsequent cooling of the particles by radiative emission, sublimation, and conduction. The model additionally includes particle heating by oxidation, accounts for the likelihood of particle annealing, and incorporates a mechanism for nonthermal photodesorption, which is required for good agreement with our experimental results. In order to investigate the fast photodesorption mechanism in more detail, we have recorded LII temporal profiles using a regeneratively amplified Nd:YAG laser with a pulse duration of 70 ps to heat the particles and a streak camera with a temporal resolution of {approx}65 ps to collect the signal. Preliminary results confirm earlier indications of a fast mechanism leading …
Date:
November 1, 2003
Creator:
Michelsen, Hope A.; Witze, Peter O. & Settersten, Thomas B.
Object Type:
Report
System:
The UNT Digital Library
Development of Detection Techniques and Diagnostics for Airborne Carbon Nanoparticles
We have recorded time-resolved LII signals from a laminar ethylene diffusion flame over a wide range of laser fluences at 532 nm. We have performed these experiments using an injection-seeded Nd:YAG laser with a pulse duration of 7 ns. The beam was spatially filtered and imaged into the flame to provide a homogeneous spatial profile. These data were used to aid in the development of a model, which will be used to test the validity of the LII technique under varying environmental conditions. The new model describes the heating of soot particles during the laser pulse and the subsequent cooling of the particles by radiative emission, sublimation, and conduction. The model additionally includes particle heating by oxidation, accounts for the likelihood of particle annealing, and incorporates a mechanism for nonthermal photodesorption, which is required for good agreement with our experimental results. In order to investigate the fast photodesorption mechanism in more detail, we have recorded LII temporal profiles using a regeneratively amplified Nd:YAG laser with a pulse duration of 70 ps to heat the particles and a streak camera with a temporal resolution of {approx}65 ps to collect the signal. Preliminary results confirm earlier indications of a fast mechanism leading …
Date:
November 1, 2003
Creator:
Michelsen, Hope Andrea
Object Type:
Report
System:
The UNT Digital Library
Development of Polymer Gel Systems to Improve Volumetric Sweep and Reduce Producing Water/Oil Ratios
Gelled polymer treatments are applied to oil reservoirs to increase oil production and to reduce water production by altering the fluid movement within the reservoir. This report describes the results of the first year of a three-year research program that is aimed at the understanding of the chemistry of gelation and the fundamental mechanisms that alter the flows of oil and water in reservoir rocks after a gel treatment. Work has focused on a widely-applied system in field applications, the partially hydrolyzed polyacrylamide-chromium acetate gel. Gelation occurs by network formation through the crosslinking of polyacrylamide molecules as a result of reaction with chromium acetate. The initial reaction between chromium acetate and one polymer is referred to as the uptake reaction. The uptake reaction was studied as functions of chromium and polymer concentrations and pH values. Experimental data were regressed to determine a rate equation that describes the uptake reaction of chromium by polyacrylamide. Pre-gel aggregates form and grow as the reactions between chromium acetate and polyacrylamide proceed. A statistical model that describes the growth of pre-gel aggregates was developed using the theory of branching processes. The model gives molecular weight averages that are expressed as functions of the conversion of …
Date:
November 1, 2003
Creator:
Willhite, G. Paul; McCool, Stan; Green, Don W.; Cheng, Min; Jain, Rajeev & Nguyen, Tuan
Object Type:
Report
System:
The UNT Digital Library
DGS Newsletter, Volume 27, Number 9, November/December 2003
Newsletter of the Dallas Genealogical Society discussing membership, Society meetings, genealogical workshops and events, and other news of interest to members.
Date:
November 2003
Creator:
Dallas Genealogical Society
Object Type:
Journal/Magazine/Newsletter
System:
The Portal to Texas History
[Día de los Muertos Parade Preparation]
Photograph of individuals preparing for a parade hosted by the Mexic-Arte Museum in honor of Día de los Muertos, or Day of the Dead. Black and white photographs are set up on an altar. Two archways decorated with paper flowers are visible. A sign in the background reads "Railroad Crossing." The photograph was taken at dusk in downtown Austin, Texas.
Date:
November 1, 2003
Creator:
Mexic-Arte Museum (Austin, Tex.)
Object Type:
Photograph
System:
The Portal to Texas History
DOE's Public Database for Green Building Case Studies: Preprint
To help capture valuable information on''green building'' case studies, the U.S. Department of Energy has created an online database for collecting, standardizing, and disseminating information about high-performance, green projects. Type of information collected includes green features, design processes, energy performance, and comparison to other high-performance, green buildings.
Date:
November 1, 2003
Creator:
Torcellini, P. A. & Crawley, D. B.
Object Type:
Article
System:
The UNT Digital Library
[Dogs in Costume]
Photograph of four small costumed dogs during a Day of the Dead celebration hosted by the Mexic-Arte Museum in Austin, Texas. A man and woman hold the dogs' leashes. Altars and patrons in costume can be seen in the background. The photograph was taken at nighttime in downtown Austin, Texas.
Date:
November 1, 2003
Creator:
Mexic-Arte Museum (Austin, Tex.)
Object Type:
Photograph
System:
The Portal to Texas History
Dose/Sensitivity in Proton Computer Tomography
N/A
Date:
November 1, 2003
Creator:
Satogata, T.; Sadrozinski, H. F. W.; Dilmanian, A.; Peggs, S. & Ruggiero, A.
Object Type:
Report
System:
The UNT Digital Library
Earth Sciences Division Research Summaries 2002-2003
Research in earth and atmospheric sciences is becoming increasingly important in light of the energy, climate change, and environmental issues facing the United States and the world. The development of new energy resources other than hydrocarbons and the safe disposal of nuclear waste and greenhouse gases (such as carbon dioxide and methane) are critical to the future energy needs and environmental safety of this planet. In addition, the cleanup of many contaminated sites in the U.S., along with the preservation and management of our water supply, remain key challenges for us as well as future generations. Addressing these energy, climate change, and environmental issues requires the timely integration of earth sciences' disciplines (such as geology, hydrology, oceanography, climatology, geophysics, geochemistry, geomechanics, ecology, and environmental sciences). This integration will involve focusing on fundamental crosscutting concerns that are common to many of these issues. A primary focus will be the characterization, imaging, and manipulation of fluids in the earth. Such capabilities are critical to many DOE applications, from environmental restoration to energy extraction and optimization. The Earth Sciences Division (ESD) of the Ernest Orlando Lawrence Berkeley National Laboratory (Berkeley Lab) is currently addressing many of the key technical issues described above. In …
Date:
November 1, 2003
Creator:
Bodvarsson, G.S.
Object Type:
Report
System:
The UNT Digital Library