Advanced Thermal Interface Materials for Power Electronics

Advancing thermal interface materials for power electronics is a critical factor in power electronics equipment. NREL aims to improve thermal interface materials for power electronics technologies.
Date: November 8, 2007
Creator: Narumanchi, S.
Object Type: Presentation
System: The UNT Digital Library
Analysis of the SL-1 Accident Using RELAPS5-3D (open access)

Analysis of the SL-1 Accident Using RELAPS5-3D

On January 3, 1961, at the National Reactor Testing Station, in Idaho Falls, Idaho, the Stationary Low Power Reactor No. 1 (SL-1) experienced a major nuclear excursion, killing three people, and destroying the reactor core. The SL-1 reactor, a 3 MW{sub t} boiling water reactor, was shut down and undergoing routine maintenance work at the time. This paper presents an analysis of the SL-1 reactor excursion using the RELAP5-3D thermal-hydraulic and nuclear analysis code, with the intent of simulating the accident from the point of reactivity insertion to destruction and vaporization of the fuel. Results are presented, along with a discussion of sensitivity to some reactor and transient parameters (many of the details are only known with a high level of uncertainty).
Date: November 8, 2007
Creator: Francisco, A.D. and Tomlinson, E. T.
Object Type: Article
System: The UNT Digital Library
Assessing Recharge and Geological Model Uncertainty at the Climax Mine Area of the Nevada Test Site (open access)

Assessing Recharge and Geological Model Uncertainty at the Climax Mine Area of the Nevada Test Site

Hydrologic analyses are commonly based on a single conceptual-mathematical model. Yet hydrologic environments are open and complex, rendering them prone to multiple interpretations and mathematical descriptions. Considering conceptual model uncertainty is a critical process in hydrologic uncertainty assessment. This study assesses recharge and geologic model uncertainty for the Climax mine area of the Nevada Test Site, Nevada. Five alternative recharge models have been independently developed for Nevada and the Death Valley area of California. These models are (1) the Maxey-Eakin model, (2 and 3) a distributed parameter watershed model with and without a runon-runoff component, and (4 and 5) a chloride mass-balance model with two zero-recharge masks, one for alluvium and one for both alluvium and elevation. Similarly, five geological models have been developed based on different interpretations of available geologic information. One of them was developed by the U.S. Geological Survey for the Death Valley Regional Flow System (DVRFS) model; the other four were developed by Bechtel Nevada for the Yucca Flat Corrective Action Unit (CAU). The Climax mine area is in the northern part of the Yucca Flat CAU, which is within the DVRFS. A total of 25 conceptual models are thus formulated based on the five recharge …
Date: November 8, 2007
Creator: Ye, M.; Pohlmann, K.; Chapman, J. & Pohll, G.
Object Type: Article
System: The UNT Digital Library

Characterization and Development of Advanced Heat Transfer Technologies

Advancing heat transfer technologies is a critical factor in power electronics equipment. NREL aims to characterize and develop advanced heat transfer technologies.
Date: November 8, 2007
Creator: Abraham, T.
Object Type: Presentation
System: The UNT Digital Library
Child Support Enforcement: $25 Annual User Fee (open access)

Child Support Enforcement: $25 Annual User Fee

None
Date: November 8, 2007
Creator: Solomon-Fears, Carmen
Object Type: Report
System: The UNT Digital Library
Comparison of New and Legacy TATBs (open access)

Comparison of New and Legacy TATBs

Two newly synthesized versions of the insensitive high explosive (IHE) 1,3,5-triamino-2,4,6-trinitrobenzenes (TATBs) were compared to two legacy explosives currently used by the Department of Energy. Except for thermal analysis, small scale safety tests could not distinguish between the different synthetic routes. Morphologies of new TATBs were less faceted and more spherical. The particle size distribution of one new material was similar to legacy TATBs, but the other was very fine. Densities and submicron structure of the new TATBs were also significantly different from the legacy explosives. Pressed pellets of the new explosives were less dense. Recrystallization from sulfolane improved the density and thermal stability of both new TATBs, though the morphology of the recrystallized TATB was nearly hexagonal platelets.
Date: November 8, 2007
Creator: Hoffman, D. M.; Willey, T. M.; Mitchell, A. R. & DePiero, S. C.
Object Type: Article
System: The UNT Digital Library
Comparison of observed and theoretical Fe L emission from CIE plasmas (open access)

Comparison of observed and theoretical Fe L emission from CIE plasmas

We analyze data from the Lawrence Livermore National Lab (LLNL) Electron Beam Ion Trap (EBIT) that simulates a CIE plasma by sweeping the electron beam to approximate a Maxwellian velocity distribution. These results are compared to spectra of confirmed astronomical CIE plasmas (e.g. outer regions of x-ray clusters) observed by XMM/RGS. We utilize the Photon Clean Method (PCM) to quantify these spectra (EBIT and XMM/RGS) in the form of ratios of Fe L lines in the emission complex near 1 keV. The variances of line fluxes are measured with bootstrap methods (Efron 1979). Both of these observations are further compared with theoretical predictions of Fe L line fluxes from APED and similar atomic databases.
Date: November 8, 2007
Creator: Carpenter, M; Beiersdorfer, P; Brown, G V; Chen, H C; Gu, M F & Jernigan, J G
Object Type: Report
System: The UNT Digital Library
A Contrarian View of How to Develop Creativiity in Science and Engineering (open access)

A Contrarian View of How to Develop Creativiity in Science and Engineering

This paper outlines what an individual engineer or scientist can do to increase her or his creativity. It then describes what educators can do and makes two proposals: (a) Reduce the number of courses required for undergraduate and graduate degrees in engineering and science and (b) change the nature of laboratory courses and Ph. D. research so that students have the freedom to try out their own ideas, with the expectation that they will make mistakes and will both expand their creativity and learn more, by doing.
Date: November 8, 2007
Creator: Perl, Martin L.
Object Type: Article
System: The UNT Digital Library
Direct Measurements of an increased threshold for stimulated Brillouin scattering with polarization smoothing in ignition hohlraum plasmas (open access)

Direct Measurements of an increased threshold for stimulated Brillouin scattering with polarization smoothing in ignition hohlraum plasmas

We demonstrate a significant reduction of stimulated Brillouin scattering by polarization smoothing. The intensity threshold is measured to increase by a factor of 1.7 {+-} 0.2 when polarization smoothing is applied. The results were obtained in a high-temperature (T{sub 3} {approx_equal} 3 keV) hohlraum plasma where filamentation is negligible in determining the backscatter threshold. These results are explained by an analytical model relevant to ICF plasma conditions that modifies the linear gain exponent to account for polarization smoothing.
Date: November 8, 2007
Creator: Froula, D; Divol, L; Berger, R L; London, R; Meezan, N; Neumayer, P et al.
Object Type: Article
System: The UNT Digital Library
Effect of Island Overlap on ELM Suppression by Resonant Magnetic Perturbations in DIII-D (open access)

Effect of Island Overlap on ELM Suppression by Resonant Magnetic Perturbations in DIII-D

Recent DIII-D [J.L. Luxon, et al., Nucl. Fusion 43, 1813 (2003)] experiments show a correlation between the extent of overlap of magnetic islands induced in the edge plasma by perturbation coils and complete suppression of Type-I edge localized modes (ELMs) in plasmas with ITER-like electron pedestal collisionality {nu}*{sub e} {approx} 0.1, flux surface shape and low edge safety factor (q{sub 95} {approx} 3.6). With fixed n = 3 resonant magnetic perturbation (RMP) strength, ELM suppression is obtained only in a finite window in the edge safety factor (q{sub 95}) consistent with maximizing the resonant component of the applied helical field. ELM suppression is obtained over an increasing range of q{sub 95} by either increasing the n = 3 RMP strength, or by adding n = 1 perturbations to 'fill in' gaps between islands across the edge plasma. The suppression of Type-I ELMs correlates with a minimum width of the edge region having magnetic islands with Chirikov parameter >1.0, based on vacuum calculations of RMP mode components excluding the plasma response or rotational shielding. The fraction of vacuum magnetic field lines that are lost from the plasma, with connection length to the divertor targets comparable to an electron-ion collisional mean free …
Date: November 8, 2007
Creator: Fenstermacher, M. E.; Evans, T. E.; Osborne, T. H.; Schaffer, M. J.; Aldan, M. P.; deGrassie, J. S. et al.
Object Type: Article
System: The UNT Digital Library
The Federal Budget: Sources of the Movement from Surplus to Deficit (open access)

The Federal Budget: Sources of the Movement from Surplus to Deficit

This report discusses about the federal budget that moved from a surplus of $128 billion in 2001 to a deficit of $413 billion in 2004. It also discusses about legislative reductions in revenue and increase in spending since 2001.
Date: November 8, 2007
Creator: Labonte, Marc
Object Type: Report
System: The UNT Digital Library
Federal Home Loan Bank System: Policy Issues (open access)

Federal Home Loan Bank System: Policy Issues

This report provides a short history and basic description of the Federal Home Loan Bank System, its responsibilities, and its ties to the government. It also discusses issues affecting the Banks and highlights the differences between the FHLB and the other two housing-related GSEs.
Date: November 8, 2007
Creator: Murphy, Edward Vincent
Object Type: Report
System: The UNT Digital Library
Food Safety: Oversight and Current Issues (open access)

Food Safety: Oversight and Current Issues

None
Date: November 8, 2007
Creator: Becker, Geoffrey S.
Object Type: Report
System: The UNT Digital Library
Ion Beam Induced Surface Modulations from Nano to Pico: Optimizing Deposition During Erosion and Erosion During Deposition. (open access)

Ion Beam Induced Surface Modulations from Nano to Pico: Optimizing Deposition During Erosion and Erosion During Deposition.

Ion beams of sufficient energy to erode a surface can lead to surface modulations that depend on the ion beam, the material surface it impinges, and extrinsic parameters such as temperature and geometric boundary conditions. Focused Ion Beam technology both enables site-specific placement of these modulations and expedites research through fast, high dose and small efficient use of material. The DualBeam (FIB/SEM) enables in situ metrology, with movies observing ripple formation, wave motion, and the influence of line defects. Nanostructures (ripples of >400nm wavelength to dots spaced <40nm) naturally grow from atomically flat surfaces during erosion, however, a steady state size may or may not be achieved as a consequence of numerous controlled parameters: temperature, angle, energy, crystallography. Geometric factors, which can be easily invoked using a FIB, enable a controlled component of deposition (and/or redeposition) to occur during erosion, and conversely allow a component of etching to be incurred during (ion-beam assisted) deposition. High angles of ion beam inclination commonly lead to 'rougher' surfaces, however, the extreme case of 90.0{sup o} etching enables deposition of organized structures 1000 times smaller than the aforementioned, video-recorded nanostructures. Orientation and position of these picostructures (naturally quantized by their atomic spacings) may be …
Date: November 8, 2007
Creator: MoberlyChan, W J & Schalek, R
Object Type: Article
System: The UNT Digital Library
Iran’s Ballistic Missile Programs: An Overview (open access)

Iran’s Ballistic Missile Programs: An Overview

None
Date: November 8, 2007
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Military Personnel: Federal Agencies Have Taken Actions to Address Servicemembers' Employment Rights, but a Single Entity Needs to Maintain Visibility to Improve Focus on Overall Program Results (open access)

Military Personnel: Federal Agencies Have Taken Actions to Address Servicemembers' Employment Rights, but a Single Entity Needs to Maintain Visibility to Improve Focus on Overall Program Results

Testimony issued by the Government Accountability Office with an abstract that begins "Since September 11, 2001, the Department of Defense (DOD) has mobilized more than 500,000 National Guard and Reserve members. As reservists return to civilian life, concerns exist about difficulties with their civilian employment. The Uniformed Services Employment and Reemployment Rights Act (USERRA) of 1994 protects the employment rights of individuals, largely National Guard and Reserve members, as they transition back to their civilian employment. GAO has issued a number of reports on agency efforts to carry out their USERRA responsibilities. DOD, the Department of Labor (DOL), the Department of Justice (DOJ), and the Office of Special Counsel (OSC) have key responsibilities under the act. GAO was asked to discuss the overall process that the agencies use to implement USERRA. Specifically, this testimony addresses (1) organizational accountability in the implementation of USERRA and (2) actions that the agencies have taken to improve their processes to implement USERRA. For this testimony, GAO drew from its most recent reports on USERRA."
Date: November 8, 2007
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Modeling EERE Deployment Programs (open access)

Modeling EERE Deployment Programs

The purpose of this report is to compile information and conclusions gathered as part of three separate tasks undertaken as part of the overall project, “Modeling EERE Deployment Programs,” sponsored by the Planning, Analysis, and Evaluation office within the Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE). The purpose of the project was to identify and characterize the modeling of deployment programs within the EERE Technology Development (TD) programs, address improvements to modeling in the near term, and note gaps in knowledge where future research is needed.
Date: November 8, 2007
Creator: Cort, Katherine A.; Hostick, Donna J.; Belzer, David B. & Livingston, Olga V.
Object Type: Report
System: The UNT Digital Library

PEEM Thermal Stress and Reliability

Advancing power electronics thermal stress and reliability is a critical factor in power electronics equipment. NREL aims to improve thermal stress and reliability of power electronics technologies.
Date: November 8, 2007
Creator: O'Keefe, M. P.
Object Type: Presentation
System: The UNT Digital Library

Power Electronic Thermal System Performance and Integration

Thermal control is a critical factor in power electronics equipment. NREL aims to integrate and improve thermal system performance in power electronics.
Date: November 8, 2007
Creator: Bennion, K.
Object Type: Presentation
System: The UNT Digital Library
Progress towards Steady State at Low Aspect Ratio on the National Spherical Torus Experiment (NSTX) (open access)

Progress towards Steady State at Low Aspect Ratio on the National Spherical Torus Experiment (NSTX)

Modifications to the plasma control capabilities and poloidal field coils of the National Spherical Torus Experiment (NSTX) have enabled a significant enhancement in shaping capability which has led to the transient achievement of a record shape factor (S ≡ q95 (Iρ⁄ αΒτ)) of ∼41 (MA m−1 Τ−1) simultaneous with a record plasma elongation of κ ≡ β ⁄ α ∼ 3. This result was obtained using isoflux control and real-time equilibrium reconstruction. Achieving high shape factor together with tolerable divertor loading is an important result for future ST burning plasma experiments as exemplified by studies for future ST reactor concepts, as well as neutron producing devices, which rely on achieving high shape factors in order to achieve steady state operation while maintaining MHD stability. Statistical evidence is presented which demonstrates the expected correlation between increased shaping and improved plasma performance.
Date: November 8, 2007
Creator: D.A. Gates, J. Menard, R. Maingi, S. Kaye, S.A. Sabbagh, S. Diem, J.R.Wilson, M.G. Bell, R.E. Bell, J. Ferron, E.D. Fredrickson, C.E. Kessel, B.P. LeBlanc, F. Levinton, J. Manickam, D. Mueller, R. Raman, T. Stevenson, D. Stutman, G. Taylor, K. Tritz, H. Yu, and the NSTX Research Team
Object Type: Report
System: The UNT Digital Library
The Reliable Replacement Warhead Program: Background and Current Developments (open access)

The Reliable Replacement Warhead Program: Background and Current Developments

None
Date: November 8, 2007
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Sexual Orientation Discrimination in Employment: Analysis of H.R. 3685, the Employment Non-Discrimination Act of 2007 (open access)

Sexual Orientation Discrimination in Employment: Analysis of H.R. 3685, the Employment Non-Discrimination Act of 2007

None
Date: November 8, 2007
Creator: unknown
Object Type: Report
System: The UNT Digital Library
SUSY Les Houches Accord 2 (open access)

SUSY Les Houches Accord 2

The Supersymmetry Les Houches Accord (SLHA) [1] provides a universal set of conventions for conveying spectral and decay information for supersymmetry analysis problems in high energy physics. Here, we propose extensions of the conventions of the first SLHA to include various generalizations: the minimal supersymmetric standard model with violation of CP, R-parity, and flavor, as well as the simplest next-to-minimal model.
Date: November 8, 2007
Creator: Allanach, B.; Balazs, C.; Belanger, G.; Bernhardt, M.; Boudjema, F.; Choudhury, D. et al.
Object Type: Article
System: The UNT Digital Library
SUSY Les Houches Accord 2 (open access)

SUSY Les Houches Accord 2

The Supersymmetry Les Houches Accord (SLHA) provides a universal set of conventions for conveying spectral and decay information for supersymmetry analysis problems in high energy physics. Here, we propose extensions of the conventions of the first SLHA to include various generalizations: the minimal supersymmetric standard model with violation of CP, R-parity, and flavor, as well as the simplest next-to-minimal model.
Date: November 8, 2007
Creator: Allanach, B.; Balazs, C.; Belanger, G.; Bernhardt, M.; Boudjema, F.; Choudhury, D. et al.
Object Type: Article
System: The UNT Digital Library