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11,964 Matching Results
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High-Order Boundary Condition Perturbation Theory for the Neutron Transport Equation
First-order boundary condition perturbation theory is extended to nth-order in transport theory for eigenvalue problems. In particular, using an unperturbed (known) solution, formalisms are developed to determine the solution to the neutron transport equation when the boundary condition of the system is perturbed. The new method requires the computation of an adjoint Green's function. The numerical solution of this function is discussed. Finally, four numerical examples are provided to verify the validity of the formalisms presented.
Date:
September 19, 2001
Creator:
McKinley, M. S. & Rahnema, F
Object Type:
Report
System:
The UNT Digital Library
Discovery and Classification of Bioinformatics Web Services
The transition of the World Wide Web from a paradigm of static Web pages to one of dynamic Web services provides new and exciting opportunities for bioinformatics with respect to data dissemination, transformation, and integration. However, the rapid growth of bioinformatics services, coupled with non-standardized interfaces, diminish the potential that these Web services offer. To face this challenge, we examine the notion of a Web service class that defines the functionality provided by a collection of interfaces. These descriptions are an integral part of a larger framework that can be used to discover, classify, and wrapWeb services automatically. We discuss how this framework can be used in the context of the proliferation of sites offering BLAST sequence alignment services for specialized data sets.
Date:
September 2, 2002
Creator:
Rocco, D. & Critchlow, T.
Object Type:
Article
System:
The UNT Digital Library
Performance-Oriented Privacy-Preserving Data Integration
Current solutions to integrating private data with public data have provided useful privacy metrics, such as relative information gain, that can be used to evaluate alternative approaches. Unfortunately, they have not addressed critical performance issues, especially when the public database is very large. The use of hashes and noise yields better performance than existing techniques while still making it difficult for unauthorized entities to distinguish which data items truly exist in the private database. As we show here, leveraging the uncertainty introduced by collisions caused by hashing and the injection of noise, we present a technique for performing a relational join operation between a massive public table and a relatively smaller private one.
Date:
September 15, 2004
Creator:
Pon, R. K. & Critchlow, T.
Object Type:
Article
System:
The UNT Digital Library
The Framework for Approximate Queries on Simulation Data
AQSim is a system intended to enable scientists to query and analyze a large volume of scientific simulation data. The system uses the state of the art in approximate query processing techniques to build a novel framework for progressive data analysis. These techniques are used to define a multi-resolution index, where each node contains multiple models of the data. The benefits of these models are two-fold: (1) they are compact representations, reconstructing only the information relevant to the analysis, and (2) the variety of models capture different aspects of the data which may be of interest to the user but are not readily apparent in their raw form. To be able to deal with the data interactively, AQSim allows the scientist to make an informed tradeoff between query response accuracy and time. In this paper, we present the framework of AQSim with a focus on its architectural design. We also show the results from an initial proof-of-concept prototype developed at LLNL. The presented framework is generic enough to handle more than just simulation data.
Date:
September 27, 2001
Creator:
Abdulla, G.; Baldwin, C.; Critchlow, T.; Kamimura, R.; Lee, B.; Musick, R. et al.
Object Type:
Article
System:
The UNT Digital Library
Design and Test of Advanced Multi-Layer Dielectric Gratings for High Energy Petawatt
In this paper we discuss recent work on the development of high damage threshold, high efficiency MLD (multilayer dielectric) diffraction gratings for use in high energy, petawatt laser systems. This effort involves a close integration between modeling, fabrication, and testing. The modeling work is used to identify grating designs that satisfy the constraints of high efficiency (>94%) and low field enhancement which is a necessary condition for high damage threshold. Subscale MLD gratings for test are being fabricated in an advanced ion-etch machine we have recently built. The testing effort is being conducted in a dedicated laboratory. The laser beam used to test the samples is based on an OPCPA (optical parametric chirped-pulse amplifier) and a compressor that can provide pulse energies up to 50mJ with pulse lengths variable from 0.3-20 ps. This test station is equipped with diagnostics to fully characterize both the spatial and temporal characteristics of the test beam at the plane of the sample. Initial results have demonstrated a dependence of damage threshold on incident angle that is in good agreement with the field enhancement calculations. We have demonstrated a grating design with a damage threshold of 3J/cm{sup 2} and are investigating manufacturability and reproducibility issues …
Date:
September 5, 2003
Creator:
Molander, W.; Komashko, A.; Britten, J.; Jones, L.; Brown, C.; Caird, J. et al.
Object Type:
Article
System:
The UNT Digital Library
Alfred A. Arraj U.S. Courthouse; Denver, Colorado: A Model of Sustainability
This brochure describes the sustainability of the Alfred A. Arraj United States Courthouse in Denver, Colorado.
Date:
September 1, 2005
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Solar is Saving Energy for the Alfred A. Arraj U.S. Courthouse: Achieving Results with Renewable Energy in the Federal Government Case Study
Solar is Saving Energy for the Alfred A. Arraj U.S. Courthouse is a case study that describes how building-integrated photovoltaic systems can be incorporated into the federal sector, and also how they can provide opportunities to meet federal renewable energy goals.
Date:
September 1, 2005
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Thick Liquid-Walled, Field-Reversed Configuration
A thick flowing layer of liquid (e.g., flibe--a molten salt, or Sn{sub 80}Li{sub 20}--a liquid metal) protects the structural walls of the field-reversed configuration (FRC) so that they can last the life of the plant even with intense 14 MeV neutron bombardment from the D-T fusion reaction. The surface temperature of the liquid rises as it passes from the inlet nozzles to the exit or receiver nozzles due to absorption of line and bremsstrahlung radiation, and neutrons. The surface temperature can be reduced by enhancement of convection near the surface to transport hot surface liquid into the cooler interior. This surface temperature must be compatible with a practical heat transport and energy recovery system. The evaporative flux from the wall driven by the surface temperature must also result in an acceptable impurity level in the core plasma. The shielding of the core by the edge plasma is modeled with a 2D transport code for the resulting impurity ions; these ions are either swept out to the distant end tanks, or diffuse to the hot plasma core. An auxiliary plasma between the edge plasma and the liquid wall can further attenuate evaporating flux of atoms and molecules by ionization. The current …
Date:
September 22, 2000
Creator:
Moir, R. W.; Bulmer, R. H.; Gulec, K.; Fogarty, P.; Nelson, B.; Ohnishi, M. et al.
Object Type:
Article
System:
The UNT Digital Library
Computerized Ultrasound Risk Evaluation (CURE) System: Development of Combined Transmission and Reflection Ultrasound with New Reconstruction Algorithms for Breast Imaging
Our Computerized Ultrasound Risk Evaluation (CURE) system has been developed to the engineering prototype stage and generated unique data sets of both transmission and reflection ultrasound (US). This paper will help define the clinical underpinnings of the developmental process and interpret the imaging results from a similar perspective. The CURE project was designed to incorporate numerous diagnostic parameters to improve upon two major areas of early breast cancer detection. CURE may provide improved tissue characterization of breast masses and reliable detection of abnormal microcalcifications found in some breast cancers and ductal carcinoma in situ (DCIS). Current breast US is limited to mass evaluation, whereas mammography also detects and guides biopsy of malignant calcifications. Screening with CURE remains a distant goal, but improved follow-up of mammographic abnormalities may represent a feasible breakthrough. Improved tissue characterization could result in reduction of the estimated one million benign biopsies each year in the United States, costing up to several billion dollars. Most breast calcifications are benign and comprise-80% of stereotactic biopsies guided by mammography. Ultrasound has the capability of finding some groups of calcifications, but further improvements in resolution should also address tissue characterization to define the soft tissue filling of ducts by DCIS. …
Date:
September 7, 2001
Creator:
Littrup, Peter J.; Duric, Neb; Azevedo, Stephen; Chambers, David; Candy, James V.; Johnson, Stephen et al.
Object Type:
Article
System:
The UNT Digital Library
Switchyard Enclosure Bolted Connection Calculations
The maximum deflection and the maximum stress were calculated for the bolted connection of the flanges. The stress is a result from both the air pressure inside the beam enclosures as well as the force from the compressed p-gasket. The results of the calculations are shown for each of the four beam enclosure types. The Safety Factor was calculated using a yield strength of 41 ksi. Calculations were also performed on the M8 bolts that are used to connect the flanges. Both the internal air pressure and the force of the compressed p-gasket induce the normal stress. The shear stress is from the weight of the unsupported beam enclosure. The calculated maximum stresses and the resulting safety factors are given. The safety factors were calculated using the maximum shear stress hypothesis and a yield strength of 30 ksi.
Date:
September 10, 2001
Creator:
Patton, Becky
Object Type:
Report
System:
The UNT Digital Library
Laser activity at 1.18 um, 1.07 um, and 0.97 umin the low phonon energy crystalline hosts KPb2Br5 and RbPb2Br5 doped with Nd3+
For the first time laser activity has been achieved in the low phonon energy, moisture-resistant bromide host crystals, neodymium-doped potassium lead bromide (Nd{sup 3+}:KPb{sub 2}Br{sub 5}) and rubidium lead bromide (Nd{sup 3+}:RbPb{sub 2}Br{sub 5}). Laser activity at 1.07 {micro}m was observed for both crystalline materials. Laser operation at the new wavelengths 1.18 {micro}m and 0.97 {micro}m resulting from the {sup 4}F{sub 5/2} + {sup 2}H{sub 9/2} {yields} {sup 4}I{sub J} transitions (J=13/2 and 11/2) in Nd:RPB was achieved for the first time in a solid state laser material. Rare earth- doped MPb{sub 2}Br{sub 5} (M=K, Rb) is a promising candidate for long wavelength infrared applications because of its low phonon frequencies and other favorable features. In principle, Nd{sup 3+}:MPb{sub 2}Br{sub 5} has high potential for laser operation at new wavelengths as well as for the realization of short-wavelength lasing due to upconversion processes.
Date:
September 15, 2004
Creator:
Rademaker, Katja; Heumann, Ernst; Payne, Stephen A.; Huber, Guenter; Krupke, William F.; Isaenko, Ludmila I. et al.
Object Type:
Article
System:
The UNT Digital Library
HADES-CCG, a new tomographic reconstruction tool
We have developed a new tomography code, HADES-CCG. This code uses HADES, a radiographic simulation code, to perform forward- and back-projection and is coupled to a Constrained Conjugate Gradient (CCG) optimizer. An iterative solution to the reconstruction problem is found which is optimal, given the detector noise model, a source model and the appropriate attenuation cross-sections. By explicitly including experimental effects in forward- and back-projection, these effects are not folded back into the object model.
Date:
September 7, 2000
Creator:
Martz, H. E., Jr.; Aufderheide, M. B., III; Hall, J.; Schach von Wittenau, A.; Goodman, D.; Logan, C. et al.
Object Type:
Article
System:
The UNT Digital Library
Advancing the R&D of Mesoscale Nondestructive Characterization
This Strategic Initiative (SI) will advance nondestructive characterization of mesoscale (millimeter-sized) objects-allowing micrometer resolution over the objects' entire volume. X-ray imaging will be developed that allows object characterization with materials that vary widely in composition, density, and geometry.
Date:
September 24, 2004
Creator:
Martz, H. E., Jr.; Aufderheide, M.; Barty, A.; Jackson, J.; Kallman, J. S.; Kozioziemski, B. et al.
Object Type:
Report
System:
The UNT Digital Library
Advancing the Technology R&D of Tabletop Mesoscale Nondestructive Characterization
This Strategic Initiative (SI) will advance nondestructive characterization of mesoscale (millimeter-sized) objects--allowing micrometer resolution over the objects' entire volume. X-ray imaging will be developed that allows object characterization with materials that vary widely in composition, density, and geometry.
Date:
September 24, 2004
Creator:
Martz, H. E., Jr.; Aufderheide, M.; Barty, A.; Jackson, J. A.; Kallman, J. S.; Kozioziemski, B. et al.
Object Type:
Report
System:
The UNT Digital Library
ALS Performance Summary - Update
High Energy Density Physics (HEDP) experiments play an important role in corroborating the improved physics codes that underlie LLNL's Stockpile Stewardship mission. Conducting these experiments, whether on the National Ignition Facility (NIF) or another national facility such as Omega, will require not only improvement in the diagnostics for measuring the experiment, but also detailed knowledge of the as-built target components and assemblies themselves. To assist in this effort, a defined set of well-known reference standards designed to represent a range of HEDP targets have been built and are being used to quantify the performance of different characterization techniques [Hibbard, et al. 2004]. Without the critical step of using reference standards for qualifying characterization tools there can be no verification of either commercial or internally-developed characterization techniques and thus an uncertainty in the input to the physics code models would exist.
Date:
September 30, 2004
Creator:
Waters, A M; Brown, W D & Martz, H. E., Jr.
Object Type:
Report
System:
The UNT Digital Library
Deterministic, Nanoscale Fabrication of Mesoscale Objects
Neither LLNL nor any other organization has the capability to perform deterministic fabrication of mm-sized objects with arbitrary, {micro}m-sized, 3-dimensional features with 20-nm-scale accuracy and smoothness. This is particularly true for materials such as high explosives and low-density aerogels. For deterministic fabrication of high energy-density physics (HEDP) targets, it will be necessary both to fabricate features in a wide variety of materials as well as to understand and simulate the fabrication process. We continue to investigate, both in experiment and in modeling, the ablation/surface-modification processes that occur with the use of laser pulses that are near the ablation threshold fluence. During the first two years, we studied ablation of metals, and we used sub-ps laser pulses, because pulses shorter than the electron-phonon relaxation time offered the most precise control of the energy that can be deposited into a metal surface. The use of sub-ps laser pulses also allowed a decoupling of the energy-deposition process from the ensuing movement/ablation of the atoms from the solid, which simplified the modeling. We investigated the ablation of material from copper, gold, and nickel substrates. We combined the power of the 1-D hydrocode ''HYADES'' with the state-of-the-art, 3-D molecular dynamics simulations ''MDCASK'' in our studies. …
Date:
September 24, 2004
Creator:
Mariella, R., Jr.; Shirk, M; Gilmer, G & Rubenchik, A
Object Type:
Report
System:
The UNT Digital Library
Texas Construction and Maintenance Report: September 2000
Monthly report documenting contracts for road construction and maintentance in Texas, organized by county and district. It includes information about each project including contractor, dates, costs, and other relevant data.
Date:
September 1, 2000
Creator:
Texas. Department of Transportation. Construction Division.
Object Type:
Report
System:
The Portal to Texas History
Texas State Park Rules and Regulations
Poster listing Texas Sate Park's rules and regulations.
Date:
September 2009
Creator:
Texas. Parks and Wildlife Department.
Object Type:
Poster
System:
The Portal to Texas History
Texas Temporary Registration, September 2001
Texas Transportation code allows for a number of temporary registration permits to be issued when it is possible or convenient for a vehicle owner or operator to issued regular Texas registration
Date:
September 2001
Creator:
Texas. Department of Transportation.
Object Type:
Report
System:
The Portal to Texas History
Texas Travel Log, September 2007
Newsletter dedicated to traveling in Texas, including information about news, locations, and events of interest to visitors as well as statistics and summaries of travel in the state.
Date:
September 2007
Creator:
Texas. Travel and Information Division.
Object Type:
Journal/Magazine/Newsletter
System:
The Portal to Texas History
Texas Travel Log, September 2005
Newsletter dedicated to traveling in Texas, including information about news, locations, and events of interest to visitors as well as statistics and summaries of travel in the state.
Date:
September 2005
Creator:
Texas. Travel and Information Division.
Object Type:
Journal/Magazine/Newsletter
System:
The Portal to Texas History
Edwards Aquifer Authority General Manager's Report, September 2003
Monthly newsletter of the general manage at the Edwards Aquifer Authority discussing news and activities of the organization as well as other information related to water in southern Texas.
Date:
September 2003
Creator:
Edwards Aquifer Authority (Tex.)
Object Type:
Journal/Magazine/Newsletter
System:
The Portal to Texas History
Edwards Aquifer Authority General Manager's Report, September 2004
Monthly newsletter of the general manage at the Edwards Aquifer Authority discussing news and activities of the organization as well as other information related to water in southern Texas.
Date:
September 2004
Creator:
Edwards Aquifer Authority (Tex.)
Object Type:
Journal/Magazine/Newsletter
System:
The Portal to Texas History
Edwards Aquifer Authority General Manager's Report, September 2002
Monthly newsletter of the general manage at the Edwards Aquifer Authority discussing news and activities of the organization as well as other information related to water in southern Texas.
Date:
September 2002
Creator:
Edwards Aquifer Authority (Tex.)
Object Type:
Journal/Magazine/Newsletter
System:
The Portal to Texas History