Advances in the theory of box integrals (open access)

Advances in the theory of box integrals

Box integrals - expectations <|{rvec r}|{sup s}> or <|{rvec r}-{rvec q}|{sup s}> over the unit n-cube (or n-box) - have over three decades been occasionally given closed forms for isolated n,s. By employing experimental mathematics together with a new, global analytic strategy, we prove that for n {le} 4 dimensions the box integrals are for any integer s hypergeometrically closed in a sense we clarify herein. For n = 5 dimensions, we show that a single unresolved integral we call K{sub 5} stands in the way of such hyperclosure proofs. We supply a compendium of exemplary closed forms that naturally arise algorithmically from this theory.
Date: June 25, 2009
Creator: Bailey, David H.; Borwein, J. M. & Crandall, R. E.
Object Type: Report
System: The UNT Digital Library
Corrosive Resistant Diamond Coatings for the Acid Based Thermo-Chemical Hydrogen Cycles (open access)

Corrosive Resistant Diamond Coatings for the Acid Based Thermo-Chemical Hydrogen Cycles

This project was designed to test diamond, diamond-like and related materials in environments that are expected in thermochemical cycles. Our goals were to build a High Temperature Corrosion Resistance (HTCR) test stand and begin testing the corrosive properties of barious materials in a high temperature acidic environment in the first year. Overall, we planned to test 54 samples each of diamond and diamond-like films (of 1 cm x 1 cm area). In addition we use a corrosion acceleration method by treating the samples at a temperature much larger than the expected operating temperature. Half of the samples will be treated with boron using the FEDOA process.
Date: June 25, 2009
Creator: Prelas, Mark A.
Object Type: Report
System: The UNT Digital Library
Cost-Effectiveness and Impact Analysis of Adoption of Standard 90.1-2007 for New York State (open access)

Cost-Effectiveness and Impact Analysis of Adoption of Standard 90.1-2007 for New York State

This report is a subset of the commercial nationwide building energy code analysis. New York has cost criteria that must also be met, and this report includes those details. This report will be finalized when the nationwide analysis report is finalized in September.
Date: June 25, 2009
Creator: Halverson, Mark A.; Gowri, Krishnan & Bartlett, Rosemarie
Object Type: Report
System: The UNT Digital Library
The MACHO Project HST Follow-Up: The Large Magellanic Cloud Microlensing Source Stars (open access)

The MACHO Project HST Follow-Up: The Large Magellanic Cloud Microlensing Source Stars

We present Hubble Space Telescope (HST) WFPC2 photometry of 13 microlensed source stars from the 5.7 year Large Magellanic Cloud (LMC) survey conducted by the MACHO Project. The microlensing source stars are identified by deriving accurate centroids in the ground-based MACHO images using difference image analysis (DIA) and then transforming the DIA coordinates to the HST frame. None of these sources is coincident with a background galaxy, which rules out the possibility that the MACHO LMC microlensing sample is contaminated with misidentified supernovae or AGN in galaxies behind the LMC. This supports the conclusion that the MACHO LMC microlensing sample has only a small amount of contamination due to non-microlensing forms of variability. We compare the WFPC2 source star magnitudes with the lensed flux predictions derived from microlensing fits to the light curve data. In most cases the source star brightness is accurately predicted. Finally, we develop a statistic which constrains the location of the Large Magellanic Cloud (LMC) microlensing source stars with respect to the distributions of stars and dust in the LMC and compare this to the predictions of various models of LMC microlensing. This test excludes at {approx}> 90% confidence level models where more than 80% of …
Date: June 25, 2009
Creator: Nelson, C. A.; Drake, A. J.; Cook, K. H.; Bennett, D. P.; Popowski, P.; Dalal, N. et al.
Object Type: Article
System: The UNT Digital Library
Measurement of the angle alpha at BABAR (open access)

Measurement of the angle alpha at BABAR

The authors present recent measurements of the CKM angle {alpha} using data collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at the SLAC National Accelerator Laboratory, operating at the {Upsilon}(4S) resonance. They present constraints on {alpha} from B {yields} {pi}{pi}, B {yields} {rho}{rho} and B {yields} {rho}{pi} decays.
Date: June 25, 2009
Creator: Perez, A.
Object Type: Article
System: The UNT Digital Library
NEW APPROACH TO ADDRESSING GAS GENERATION IN RADIOACTIVE MATERIAL PACKAGING (open access)

NEW APPROACH TO ADDRESSING GAS GENERATION IN RADIOACTIVE MATERIAL PACKAGING

Safety Analysis Reports for Packaging (SARP) document why the transportation of radioactive material is safe in Type A(F) and Type B shipping containers. The content evaluation of certain actinide materials require that the gas generation characteristics be addressed. Most packages used to transport actinides impose extremely restrictive limits on moisture content and oxide stabilization to control or prevent flammable gas generation. These requirements prevent some users from using a shipping container even though the material to be shipped is fully compliant with the remaining content envelope including isotopic distribution. To avoid these restrictions, gas generation issues have to be addressed on a case by case basis rather than a one size fits all approach. In addition, SARP applicants and review groups may not have the knowledge and experience with actinide chemistry and other factors affecting gas generation, which facility experts in actinide material processing have obtained in the last sixty years. This paper will address a proposal to create a Gas Generation Evaluation Committee to evaluate gas generation issues associated with Safety Analysis Reports for Packaging material contents. The committee charter could include reviews of both SARP approved contents and new contents not previously evaluated in a SARP.
Date: June 25, 2009
Creator: Watkins, R; Leduc, D & Askew, N
Object Type: Article
System: The UNT Digital Library
Recent Results From BaBar in Tau Physics (open access)

Recent Results From BaBar in Tau Physics

The BaBar collaboration has accumulated over 400 million {tau}-pairs which can be used to study charged leptonic and hadronic weak currents to unprecedented precision. This note presents results on lepton universality, measurements of |V{sub us}|, and searches for {tau} decays which violate lepton flavour conservation, or {tau} decays that proceed through a suppressed second class current.
Date: June 25, 2009
Creator: Lewczuk, Mateusz
Object Type: Article
System: The UNT Digital Library
REVERSIBLE AND IRREVERSIBLE PASSIVATION OF A LA-NI-AL ALLOY (open access)

REVERSIBLE AND IRREVERSIBLE PASSIVATION OF A LA-NI-AL ALLOY

This paper seeks to explore some of the effects of passivating a LaNi{sub 4.25}Al{sub 0.75} sample by air oxidation under controlled conditions. Passivation of this metal hydride alloy seems to have two distinct regimes. The first occurs with air oxidation at 80 C and 20 C. It is characterized by complete reversibility upon hydrogen readsorption, although said readsorption is hindered substantially at room temperature, requiring the material to be heated to produce the reactivation. The second regime is illustrated by 130 C air oxidation and is characterized by irreversible loss of hydrogen absorption capacity. This passivation does not hinder hydrogen readsorption into the remaining hydride material.
Date: June 25, 2009
Creator: Shanahan, K. & Klein, J.
Object Type: Article
System: The UNT Digital Library
Structural Analyses of Fuel Casks Subjected to Bolt Preload, Internal Pressure and Sequential Dynamic Impacts (open access)

Structural Analyses of Fuel Casks Subjected to Bolt Preload, Internal Pressure and Sequential Dynamic Impacts

Large fuel casks subjected to the combined loads of closure bolt tightening, internal pressure and sequential dynamic impacts present challenges when evaluating their performance in the Hypothetical Accident Conditions (HAC) specified in the Code of Federal Regulations Title 10 Part 71 (10CFR71). Testing is often limited by cost, difficulty in preparing test units and the limited availability of facilities which can carry out such tests. In the past, many casks were evaluated without testing by using simplified analytical methods. In addition, there are no realistic analyses of closure bolt stresses for HAC conditions reported in the open literature. This paper presents a numerical technique for analyzing the accumulated damages of a large fuel cask caused by the sequential loads of the closure bolt tightening and the internal pressure as well as the drop and crash dynamic loads. The bolt preload and the internal pressure are treated as quasi-static loads so that the finite element method with explicit numerical integration scheme based on the theory of wave propagation can be applied. The dynamic impacts with short durations such as the 30-foot drop and the 40-inch puncture for the hypothetical accident conditions specified in 10CFR71 are also analyzed by using the finite-element …
Date: June 25, 2009
Creator: Wu, T.
Object Type: Article
System: The UNT Digital Library
A Supernodal Approach to Incomplete LU Factorization with Partial Pivoting (open access)

A Supernodal Approach to Incomplete LU Factorization with Partial Pivoting

We present a new supernode-based incomplete LU factorization method to construct a preconditioner for solving sparse linear systems with iterative methods. The new algorithm is primarily based on the ILUTP approach by Saad, and we incorporate a number of techniques to improve the robustness and performance of the traditional ILUTP method. These include the new dropping strategies that accommodate the use of supernodal structures in the factored matrix. We present numerical experiments to demonstrate that our new method is competitive with the other ILU approaches and is well suited for today's high performance architectures.
Date: June 25, 2009
Creator: Li, Xiaoye Sherry & Shao, Meiyue
Object Type: Article
System: The UNT Digital Library
TANK FARM INTERIM SURFACE BARRIER MATERIALS AND RUNOFF ALTERNATIVES STUDY (open access)

TANK FARM INTERIM SURFACE BARRIER MATERIALS AND RUNOFF ALTERNATIVES STUDY

This report identifies candidate materials and concepts for interim surface barriers in the single-shell tank farms. An analysis of these materials for application to the TY tank farm is also provided.
Date: June 25, 2009
Creator: MJ, HOLM
Object Type: Report
System: The UNT Digital Library
Thorough characterization of a EUV mask (open access)

Thorough characterization of a EUV mask

We reported that we were successful in our 45nm technology node device demonstration in February 2008 and 22nm node technology node device patterning in February 2009 using ASML's Alpha Demo Tool (ADT). In order to insert extreme ultraviolet (EUV) lithography at the 15nm technology node and beyond, we have thoroughly characterized one EUV mask, a so-called NOVACD mask. In this paper, we report on three topics, The first topic is an analysis of line edge roughness (LER) using a mask Scanning Electron Microscope (SEM), an Atomic Force Microscope (AFM) and the Actinic Inspection Tool (AIT) to compare resist images printed with the ASML ADT. The results of the analysis show a good correlation between the mask AFM and the mask SEM measurements, However, the resist printing results for the isolated space patterns are slightly different. The cause ofthis discrepancy may be resist blur, image log slope and SEM image quality and so on. The second topic is an analysis of mask topography using an AFM and relative reflectivity of mirror and absorber surface using the AIT, The AFM data show 6 and 7 angstrom rms roughness for mirror and absorber, respectively. The reflectivity measurements show that the mirror reflects EUV …
Date: June 25, 2009
Creator: Mizuno, H.; McIntyre, G.; Koay, C.-W.; Burkhardt, M.; He, L.; Hartley, J. et al.
Object Type: Article
System: The UNT Digital Library
The Use of Weighting in Periodicity Searches in All-Sky Monitor Data: Applications to the GLAST LAT (open access)

The Use of Weighting in Periodicity Searches in All-Sky Monitor Data: Applications to the GLAST LAT

The light curves produced by all-sky monitors, such as the Rossi X-ray Timing Explorer All-Sky Monitor and the Swift Burst Alert Telescope (BAT), generally have non-uniform error bars. In searching for periodic modulation in this type of data using power spectra it can be important to use appropriate weighting of data points to achieve the best sensitivity. It was recently demonstrated that for Swift BAT data a simple weighting scheme can actually sometimes reduce the sensitivity of the power spectrum depending on source brightness. Instead, a modified weighting scheme, based on the Cochran semi-weighted mean, gives improved results independent of source brightness. We investigate the benefits of weighting power spectra in period searches using simulated GLAST LAT observations of {gamma}-ray binaries.
Date: June 25, 2009
Creator: Corbet, Robin & Dubois, Richard
Object Type: Article
System: The UNT Digital Library