Internet Taxation: Issues and Legislation in the 108th Congress (open access)

Internet Taxation: Issues and Legislation in the 108th Congress

None
Date: May 4, 2004
Creator: Maguire, Steven & Noto, Nonna A.
Object Type: Report
System: The UNT Digital Library
Kazakhstan: Current Developments and U.S. Interests (open access)

Kazakhstan: Current Developments and U.S. Interests

None
Date: May 4, 2004
Creator: Nichol, Jim
Object Type: Report
System: The UNT Digital Library
Air Force Aerial Refueling (open access)

Air Force Aerial Refueling

Aerial refueling aircraft are key to military air operations. The U.S. tanker fleet is numerous and effective, but old. Modernizing or replacing the current fleet of tankers presents the Department of Defense (DOD) with difficult choices in terms of desired capabilities, force structure, and budget. The Air Force’s proposal to lease 100 Boeing 767 aircraft to replace it’s KC-135E fleet is controversial.
Date: May 4, 2004
Creator: Bolkcom, Christopher
Object Type: Report
System: The UNT Digital Library
Unfunded Mandates Reform Act Summarized (open access)

Unfunded Mandates Reform Act Summarized

The term "unfunded mandates" generally refers to requirements that a unit of government imposes without providing funds to pay for costs of compliance. The Unfunded Mandates Reform Act (UMRA) establishes mechanisms to limit federal imposition of unfunded mandates on other levels of government and on the private sector. This report provides a summary of UMRA and any related issues.
Date: May 4, 2004
Creator: Beth, Richard S. & Bea, Keith
Object Type: Report
System: The UNT Digital Library
Data Mining: Federal Efforts Cover a Wide Range of Uses (open access)

Data Mining: Federal Efforts Cover a Wide Range of Uses

A letter report issued by the General Accounting Office with an abstract that begins "Both the government and the private sector are increasingly using "data mining"--that is, the application of database technology and techniques (such as statistical analysis and modeling) to uncover hidden patterns and subtle relationships in data and to infer rules that allow for the prediction of future results. As has been widely reported, many federal data mining efforts involve the use of personal information that is mined from databases maintained by public as well as private sector organizations. GAO was asked to survey data mining systems and activities in federal agencies. Specifically, GAO was asked to identify planned and operational federal data mining efforts and describe their characteristics."
Date: May 4, 2004
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
Ponderomotive Barrier as a Maxwell Demon (open access)

Ponderomotive Barrier as a Maxwell Demon

The possibility of efficient ponderomotive current drive in a magnetized plasma was reported recently in [Phys. Rev. Lett. 91, 205004 (2003)]. Precise limitations on the efficiency are now given through a comprehensive analytical and numerical study of single-particle dynamics under the action of a cyclotron-resonant rf drive in various field configurations. Expressions for the particle energy gain and acceleration along the dc magnetic field are obtained. The fundamental correlation between the two effects is described. A second fundamental quantity, namely the ratio of the potential barrier to the energy gain, can be changed by altering the field configuration. The asymmetric ponderomotive current drive effect can be optimized by minimizing the transverse heating.
Date: May 4, 2004
Creator: Dodin, I. Y.; Fisch, N. J. & Rax, J. M.
Object Type: Report
System: The UNT Digital Library
E781 Hyperon Spectrometer Constants (open access)

E781 Hyperon Spectrometer Constants

This is a discussion of the physical measurements, sizes, distances and magnetic fields of the Hyperon Spectrometer Magnet and its components. Some we get from construction drawings (like the target dimensions) and others from measurements in differing coordinate systems. Included also are the properties of the hyperon productions targets used in E781.
Date: May 4, 2004
Creator: Lach, Joseph T.
Object Type: Report
System: The UNT Digital Library
Study of new FNAL-NICADD extruded scintillator as active media of large EMCal of ALICE at LHC (open access)

Study of new FNAL-NICADD extruded scintillator as active media of large EMCal of ALICE at LHC

The current conceptual design of proposed Large EMCal of ALICE at LHC is based largely on the scintillating mega-tile/fiber technology implemented in CDF Endplug upgrade project and in both barrel and endcap electromagnetic calorimeters of the STAR. The cost of scintillating material leads us to the choice of extruded polystyrene based scintillator, which is available in new FNAL-NICADD facility. Result of optical measurements, such as light yield and light yield variation, show that it is possible to use this material as active media of Large EMCal of ALICE at LHC.
Date: May 4, 2004
Creator: al., Oleg A. Grachov et
Object Type: Article
System: The UNT Digital Library
A physically based numerical approach for modeling fracture-matrix interaction in fractured reservoirs (open access)

A physically based numerical approach for modeling fracture-matrix interaction in fractured reservoirs

Modeling fracture-matrix interaction within a multiple-phase flow system is a key issue for fractured reservoir simulation. Commonly used mathematical models for dealing with such interactions employ dual- or multiple-continuum concepts, in which fractures and matrix are represented as overlapping, different, but interconnected continua, described by parallel sets of conservation equations. The conventional single-point upstream weighting scheme is most commonly used to estimate flow mobility for fracture-matrix flow. However, such a scheme may have serious limitations or flaws, which lead to unphysical solutions or significant numerical errors. To overcome the limitations of the conventional upstream weighting scheme, this paper presents a physically based modeling approach for estimating physically correct relative permeability in calculating multiphase flow between fractures and the matrix, using continuity of capillary pressure at the fracture-matrix interface. The proposed approach has been implemented into two multiphase reservoir simulators and verified using analytical solutions and laboratory experimental data. The new method is demonstrated to be accurate, numerically efficient, and easy to implement in dual- or multiple-continuum reservoir simulators.
Date: May 4, 2004
Creator: Wu, Yu-Shu & Pruess, Karsten
Object Type: Article
System: The UNT Digital Library
Evaluation of Proposed New LLW Disposal Activity Disposal of LLW in a Mega Trench rather than in Slit Trenches (open access)

Evaluation of Proposed New LLW Disposal Activity Disposal of LLW in a Mega Trench rather than in Slit Trenches

The effect of disposing of low-level waste in a much larger trench than the slit trenches analyzed in the revised performance assessment for the E-Area low-level waste facility is evaluated. The conclusion of the evaluation is that such disposal is bounded by the performance assessment if two restrictions are imposed. These restrictions are: the radionuclide inventory limits for slit trench disposal derived from the revised performance assessment, rather than the radionuclide concentration or package limits, are applied to the larger trench. For stabilized waste radionuclide concentration or package limits derived from the inventory limits for these wasteforms calculated in the performance assessment and the volumetric waste capacity of the entire MegaTrench may be used if this waste fills a large-enough segment of the trench to provide structural support for the closure cap, as assumed in the performance assessment and the stabilized waste is segregated from the unstabilized waste by emplacing the stabilized waste along the edge of the trench and separating the stabilized waste from the unstabilized waste by a minimum of two feet of soil or other material with similar hydraulic properties.
Date: May 4, 2004
Creator: WILHITE, ELMERL.
Object Type: Report
System: The UNT Digital Library
A node-centered local refinement algorithm for poisson's equation in complex geometries (open access)

A node-centered local refinement algorithm for poisson's equation in complex geometries

This paper presents a method for solving Poisson's equation with Dirichlet boundary conditions on an irregular bounded three-dimensional region. The method uses a nodal-point discretization and adaptive mesh refinement (AMR) on Cartesian grids, and the AMR multigrid solver of Almgren. The discrete Laplacian operator at internal boundaries comes from either linear or quadratic (Shortley-Weller) extrapolation, and the two methods are compared. It is shown that either way, solution error is second order in the mesh spacing. Error in the gradient of the solution is first order with linear extrapolation, but second order with Shortley-Weller. Examples are given with comparison with the exact solution. The method is also applied to a heavy-ion fusion accelerator problem, showing the advantage of adaptivity.
Date: May 4, 2004
Creator: McCorquodale, Peter; Colella, Phillip; Grote, David P. & Vay, Jean-Luc
Object Type: Article
System: The UNT Digital Library
Minature Nuclear Magnetic Resonance Spectrometer for In-situ and In-Process Analysis and Monitoring (open access)

Minature Nuclear Magnetic Resonance Spectrometer for In-situ and In-Process Analysis and Monitoring

The effort in this project has been in 3 distinct directions. (1) First, we focused on development of minature microfabricated micro-coil NMR detectors with maximum Signal-to-Noise (SNR) ratio. (2) Secondly, we focused on design of minature micro-coil NMR detectors that have minimal effect on the NMR spectrum distortions. (3) Lastly we focused on the development of a permanent magnet capable of generating fields on the order of 1 Tesla with better than 10 ppm uniformity.
Date: May 4, 2004
Creator: Friedman, Gennady
Object Type: Report
System: The UNT Digital Library
On the development of a coupled land surface and groundwater model (open access)

On the development of a coupled land surface and groundwater model

Management of surface water quality is often complicated by interactions between surface water and groundwater. Traditional Land-Surface Models (LSM) used for numerical weather prediction, climate projection, and as inputs to water management decision support systems, do not treat the LSM lower boundary in a fully process-based fashion. LSMs have evolved from a leaky bucket to more sophisticated land surface water and energy budget models that typically have a so-called basement term to depict the bottom model layer exchange with deeper aquifers. Nevertheless, the LSM lower boundary is often assumed zero flux or the soil moisture content is set to a constant value; an approach that while mass conservative, ignores processes that can alter surface fluxes, runoff, and water quantity and quality. Conversely, groundwater models (GWM) for saturated and unsaturated water flow, while addressing important features such as subsurface heterogeneity and three-dimensional flow, often have overly simplified upper boundary conditions that ignore soil heating, runoff, snow and root-zone uptake. In the present study, a state-of-the-art LSM (CLM) and a variably-saturated GWM (ParFlow) have been coupled as a single column model. A set of simulations based on synthetic data and data from the Project for Intercomparison of Landsurface Parameterization Schemes (PILPS), version …
Date: May 4, 2004
Creator: Maxwell, R. M. & Miller, N. L.
Object Type: Article
System: The UNT Digital Library
Development of Chemical Treatment Alternatives for Tetraphenylborate Destruction in Tank 48H (open access)

Development of Chemical Treatment Alternatives for Tetraphenylborate Destruction in Tank 48H

This study assessed chemical treatment options for decomposing the tetraphenylborate in High Level Waste (HLW) Tank 48H. Tank 48H, located at the Savannah River Site in Aiken, SC, contains approximately one million liters of HLW. The tetraphenylborate slurry represents legacy material from commissioning of an In Tank Precipitation process to separate radioactive cesium and actinides from the non radioactive chemicals. During early operations, the process encountered an unplanned chemical reaction that catalytically decomposed the excess tetraphenylborate producing benzene. Subsequent research indicated that personnel could not control the operations within the existing equipment to both meet the desired treatment rate for the waste and maintain the benzene concentration within allowable concentrations. Since then, the Department of Energy selected an alternate treatment process for handling high-level waste at the site. However, the site must destroy the tetraphenylborate before returning the tank to HLW service. The research focuses on identifying treatments to decompose tetraphenylborate to the maximum extent feasible, with a preference for decomposition methods that produce carbon dioxide rather than benzene. A number of experiments examined whether the use of oxidants, catalysts or acids proved effective in decomposing the tetraphenylborate. Additional experiments developed an understanding of the solid, liquid and gas decomposition …
Date: May 4, 2004
Creator: Lambert, Daniel P.
Object Type: Article
System: The UNT Digital Library
Valence band hybridization in N-rich GaN1-xAsx alloys (open access)

Valence band hybridization in N-rich GaN1-xAsx alloys

We have used photo-modulated transmission and optical absorption spectroscopies to measure the composition dependence of interband optical transitions in N-rich GaN{sub 1-x}As{sub x} alloys with x up to 0.06. The direct bandgap gradually decreases as x increases. In the dilute x limit, the observed band gap approaches 2.8 eV; this limiting value is attributed to a transition between the As localized level, which has been previously observed in As-doped GaN at 0.6 eV above the valence band maximum in As-doped GaN, and the conduction band minimum. The structure of the valence band of GaN{sub 1-x}As{sub x} is explained by the hybridization of the localized As states with the extended valence band states of GaN matrix. The hybridization is directly confirmed by soft x-ray emission experiments. To describe the electronic structure of the GaN{sub 1-x}As{sub x} alloys in the entire composition range a linear interpolation is used to combine the effects of valence band hybridization in N-rich alloys with conduction band anticrossing in As-rich alloys.
Date: May 4, 2004
Creator: Wu, J.; Walukiewicz, W.; Yu, K. M.; Denlinger, J. D.; Shan, W.; Ager, J. W., III et al.
Object Type: Article
System: The UNT Digital Library
Detecting DNA regulatory motifs by incorporating positional trendsin information content (open access)

Detecting DNA regulatory motifs by incorporating positional trendsin information content

On the basis of the observation that conserved positions in transcription factor binding sites are often clustered together, we propose a simple extension to the model-based motif discovery methods. We assign position-specific prior distributions to the frequency parameters of the model, penalizing deviations from a specified conservation profile. Examples with both simulated and real data show that this extension helps discover motifs as the data become noisier or when there is a competing false motif.
Date: May 4, 2004
Creator: Kechris, Katherina J.; van Zwet, Erik; Bickel, Peter J. & Eisen,Michael B.
Object Type: Article
System: The UNT Digital Library
Broadband Internet Access: Background and Issues (open access)

Broadband Internet Access: Background and Issues

This report contains background information and issues of broadband internet access.
Date: May 4, 2004
Creator: Gilroy, Angele A. & Kruger, Lennard G.
Object Type: Report
System: The UNT Digital Library
Kazakhstan: Current Developments and U.S. Interests (open access)

Kazakhstan: Current Developments and U.S. Interests

This report discusses the relationship between the U.S. and Kazakhstan. Kazakhstan is becoming an important power in Central Asia by virtue of its large territory, ample natural resources, and strategic location. However, it faces political, ethnic, economic, and environmental challenges to its stability and integrity. After the terrorist attacks on the United States on September 11, 2001, Kazakhstan granted overflight rights for U.S.-led coalition actions in Afghanistan, and in 2003 provided some troops for post-conflict rebuilding in Iraq.
Date: May 4, 2004
Creator: Nichol, Jim
Object Type: Report
System: The UNT Digital Library
Science and Technology for Bioterrorism Defense (open access)

Science and Technology for Bioterrorism Defense

The Lawrence Livermore National Laboratory (LLNL) Chemical & Biological National Security Program (CBNP) provides science, technology, and integrated systems for chemical and biological security. Our approach is to develop and field systems that dramatically improve the nation's capabilities to prevent, prepare for, detect, and respond to terrorist use of chemical or biological weapons.
Date: May 4, 2004
Creator: Fitch, J P
Object Type: Article
System: The UNT Digital Library
Reconstruction of Sedimentary Rock Based on MechanicalProperties (open access)

Reconstruction of Sedimentary Rock Based on MechanicalProperties

We describe a general, physics-based approach to numericalreconstruction of the geometrical structure and mechanical properties ofnatural sedimentary rock in 3D. Our procedure consists of three mainsteps: sedimentation, compaction, and diagenesis, followed by theverification of rock mechanical properties. The dynamic geologicprocesses of grain sedimentation and compaction are simulated by solvinga dimensionless form of Newton's equations of motion for an ensemble ofgrains. The diagenetic rock transformation is modeled using a cementationalgorithm, which accounts for the effect of rock grain size on therelative rate of cement overgrowth. Our emphasis is on unconsolidatedsand and sandstone. The main input parameters are the grain sizedistribution, the final rock porosity, the type and amount of cement andclay minerals, and grain mechanical properties: the inter-grain frictioncoefficient, the cement strength, and the grain stiffness moduli. We usea simulated 2D Fontainebleau sandstone to obtain the grain mechanicalproperties. This Fontainebleau sandstone is also used to study theinitiation, growth, and coalescence of micro-cracks under increasingvertical stress. The box fractal dimension of the micro-crackdistribution, and its variation with the applied stress areestimated.
Date: May 4, 2004
Creator: Jin, Guodong; Patzek, Tad W. & Silin, Dmitry B.
Object Type: Report
System: The UNT Digital Library
Direct Determination of the Equilibrium Unbinding Potential Profile for a Short DNA Duplex from Force Spectroscopy Data (open access)

Direct Determination of the Equilibrium Unbinding Potential Profile for a Short DNA Duplex from Force Spectroscopy Data

Modern force microscopy techniques allow researchers to use mechanical forces to probe interactions between biomolecules. However, such measurements often happen in non-equilibrium regime, which precludes straightforward extraction of the equilibrium energy information. Here we use the work averaging method based on Jarzynski equality to reconstruct the equilibrium interaction potential from the unbinding of a complementary 14-mer DNA duplex from the results of non-equilibrium single-molecule measurements. The reconstructed potential reproduces most of the features of the DNA stretching transition, previously observed only in equilibrium stretching of long DNA sequences. We also compare the reconstructed potential with the thermodynamic parameters of DNA duplex unbinding and show that the reconstruction accurately predicts duplex melting enthalpy.
Date: May 4, 2004
Creator: Noy, A
Object Type: Article
System: The UNT Digital Library
Titan's 2 micron Surface Albedo and Haze Optical Depth in 1996-2004 (open access)

Titan's 2 micron Surface Albedo and Haze Optical Depth in 1996-2004

We observed Titan in 1996-2004 with high-resolution 2 {micro}m speckle and adaptive optics imaging at the W.M. Keck Observatory. By observing in a 2 {micro}m broadband filter we obtain images that have contributions from both Titan's surface and atmosphere. We have modeled Titan's atmosphere using a plane-parallel radiative transfer code that has been corrected to agree with 3-D Monte Carlo predictions. We find that Titan's surface albedo ranges from {le} 0:02 in the darkest equatorial region of the trailing hemisphere to {approx_equal} 0:1 in the brightest areas of the leading hemisphere. Over the past quarter of a Saturnian year haze optical depth in Titan's Southern hemisphere has decreased substantially from a value of 0.48 in 1996 down to 0.18 in 2004, while the northern haze has been increasing over the past few years. As a result of these changes, in 2004 the North/South haze asymmetry at K' band has disappeared.
Date: May 4, 2004
Creator: Gibbard, S. G.; de Pater, I.; Macintosh, B. A.; Roe, H. G.; Max, C. E.; Young, E. F. et al.
Object Type: Article
System: The UNT Digital Library