Measurements of the Optical Constants of Scandium in the 50-1300eV Range. (open access)

Measurements of the Optical Constants of Scandium in the 50-1300eV Range.

Scandium containing multilayers have been produced with very high reflectivity in the soft x-ray spectrum. Accurate optical constants are required in order to model the multilayer reflectivity. Since there are relatively few measurements of the optical constants of Scandium in the soft x-ray region we have performed measurements over the energy range of 50-1,300 eV. Thin films of Scandium were deposited by ion-assisted magnetron sputtering at Linkoping University and DC Magnetron sputtering at CXRO. Transmission measurements were performed at the Advanced Light Source beamline 6.3.2. The absorption coefficient was deduced from the measurements and the dispersive part of the index of refraction was obtained using the Kramers-Kronig relation. The measured optical constants are used to model the near-normal incidence reflectivity of Cr/Sc multilayers near the Sc L{sub 2,3} edge.
Date: October 3, 2004
Creator: Aquila, A. L.; Salmassi, F.; Gullikson, E. M.; Eriksson, F. & Birch, J.
System: The UNT Digital Library
Mechanical and Thermal Properties of Ultra-High Carbon Steel Containing Aluminum (open access)

Mechanical and Thermal Properties of Ultra-High Carbon Steel Containing Aluminum

The properties of ultrahigh carbon steels (UHCS) are strongly influenced by aluminum additions. Hardness studies of quenched UHCS-Al alloys reveal that the temperature for the start of transformation increases with increases in aluminum content. It is shown that this change is a function of the atomic percent of solute and of the valence state when comparisons are made with UHCSs containing silicon and tin as solutes. The thermal expansion of UHCSs with dilute aluminum additions shows no discontinuity in the vicinity of the ferrite-austenite transformation temperature. This is the result of a three phase region of ferrite, carbides and austenite. The slope of the expansion curve is higher in the austenite range than in the ferrite range as a result of the dissolution of carbon in austenite with temperature. Processing to achieve a fine grain size in UHCS-Al alloys was principally by hot and warm working (HWW) followed by isothermal warm working (IWW). The high temperature mechanical properties of a UHCS-10Al-1.5C material show nearly Newtonian-viscous behavior at 900 to 1000 C. Tensile elongations of 1200% without failure were achieved in the 1.5%C material. The high oxidation corrosion resistance of the UHCS-10Al materials is described.
Date: October 3, 2005
Creator: Syn, C. K.; Lesuer, D. R.; Goldberg, A.; Tsai, H. C. & Sherby, O. D.
System: The UNT Digital Library
E.M. and Hadronic Shower Simulation with FLUKA (open access)

E.M. and Hadronic Shower Simulation with FLUKA

A description of the main features of e.m. and hadronic shower simulation models used in the FLUKA code is summarized and some recent applications are discussed. The general status of the FLUKA project is also reported.
Date: October 3, 2005
Creator: Battistoni, G.; Fasso, A.; Ferrari, A.; Ranft, J.; Rubbia, A.; Sala, P.R. et al.
System: The UNT Digital Library
Impacts of Renewable Fuel and Electricity Standards on State Economies (Poster) (open access)

Impacts of Renewable Fuel and Electricity Standards on State Economies (Poster)

This poster, submitted for the CU Energy Initiative/NREL Symposium on October 3, discusses the impacts of renewable fuel and electricity standards on state economies.
Date: October 3, 2006
Creator: Brown, E.; Cory, K.; Brown, J.; Bird, L. & Sweezey, B.
System: The UNT Digital Library
Core Scale and Pore Scale Studies of Carbon Dioxide Migration Insaline Formations (open access)

Core Scale and Pore Scale Studies of Carbon Dioxide Migration Insaline Formations

Understanding core scale and pore scale migration of CO2 will improve our ability to predict storage capacity and determine the effectiveness of solubility and capillary (residual CO2) trapping. While the theoretical underpinnings of multi-phase flow are well developed for oil and gas production, there are few, if any measurements relevant to CO2 storage in saline formations. To fill this gap, core scale and porescale measurements of CO2 migration in sandstone are being conducted.
Date: October 3, 2005
Creator: Benson, Sally M.; Tomutsa, Liviu; Silin, Dmitriy; Kneafsey,Timothy & Miljkovic, Ljubinko
System: The UNT Digital Library
Are Quasar Jets Matter Or Poynting Flux Dominated? (open access)

Are Quasar Jets Matter Or Poynting Flux Dominated?

If quasar jets are accelerated by magnetic fields but terminate as matter dominated, where and how does the transition occur between the Poynting-dominated and matter-dominated regimes? To address this question, we study constraints which are imposed on the jet structure by observations at different spatial scales. We demonstrate that observational data are consistent with a scenario where the acceleration of a jet occurs within 10{sup 3-4}R{sub g}. In this picture, the non-thermal flares--important defining attributes of the blazar phenomenon--are produced by strong shocks formed in the region where the jet inertia becomes dominated by matter. Such shocks may be formed due to collisions between the portions of a jet accelerated to different velocities, and the acceleration differentiation is very likely to be related to global MHD instabilities.
Date: October 3, 2005
Creator: Sikora, Marek; /Warsaw, Copernicus Astron. Ctr.; Madejski, Greg M.; /SLAC /KIPAC, Menlo Park; Lasota, Jean-Pierre; /Paris, Inst. Astrophys. et al.
System: The UNT Digital Library
Multiphase imaging of gas flow in a nanoporous material usingremote detection NMR (open access)

Multiphase imaging of gas flow in a nanoporous material usingremote detection NMR

Pore structure and connectivity determine how microstructured materials perform in applications such as catalysis, fluid storage and transport, filtering, or as reactors. We report a model study on silica aerogel using a recently introduced time-of-flight (TOF) magnetic resonance imaging technique to characterize the flow field and elucidate the effects of heterogeneities in the pore structure on gas flow and dispersion with Xe-129 as the gas-phase sensor. The observed chemical shift allows the separate visualization of unrestricted xenon and xenon confined in the pores of the aerogel. The asymmetrical nature of the dispersion pattern alludes to the existence of a stationary and a flow regime in the aerogel. An exchange time constant is determined to characterize the gas transfer between them. As a general methodology, this technique provides new insights into the dynamics of flow in porous media where multiple phases or chemical species may be present.
Date: October 3, 2005
Creator: Harel, Elad; Granwehr, Josef; Seeley, Juliette A. & Pines, Alex
System: The UNT Digital Library
IRIS Reactor a Suitable Option to Provide Energy and Water Desalination for the Mexican Northwest Region (open access)

IRIS Reactor a Suitable Option to Provide Energy and Water Desalination for the Mexican Northwest Region

The Northwest region of Mexico has a deficit of potable water, along this necessity is the region growth, which requires of additional energy capacity. The IRIS reactor offers a very suitable source of energy given its modular size of 300 MWe and it can be coupled with a desalination plant to provide the potable water for human consumption, agriculture and industry. The present paper assess the water and energy requirements for the Northwest region of Mexico and how the deployment of the IRIS reactor can satisfy those necessities. The possible sites for deployment of Nuclear Reactors are considered given the seismic constraints and the closeness of the sea for external cooling. And in the other hand, the size of the desalination plant and the type of desalination process are assessed accordingly with the water deficit of the region.
Date: October 3, 2004
Creator: Alonso, G.; Ramirez, R.; Gomez, C. & Viais, J.
System: The UNT Digital Library
Life Cycle Assessments Confirm the Need for Hydropower and Nuclear Energy (open access)

Life Cycle Assessments Confirm the Need for Hydropower and Nuclear Energy

This paper discusses the use of life cycle assessments to confirm the need for hydropower and nuclear energy.
Date: October 3, 2004
Creator: Gagnon, L.
System: The UNT Digital Library
How to Shape a Successful Repository Program: Staged Development of Geologic Repositories for High-Level Waste (open access)

How to Shape a Successful Repository Program: Staged Development of Geologic Repositories for High-Level Waste

Programs to manage and ultimately dispose of high-level radioactive wastes are unique from scientific and technological as well as socio-political aspects. From a scientific and technological perspective, high-level radioactive wastes remain potentially hazardous for geological time periods--many millennia--and scientific and technological programs must be put in place that result in a system that provides high confidence that the wastes will be isolated from the accessible environment for these many thousands of years. Of course, ''proof'' in the classical sense is not possible at the outset, since the performance of the system can only be known with assurance, if ever, after the waste has been emplaced for those geological time periods. Adding to this challenge, many uncertainties exist in both the natural and engineered systems that are intended to isolate the wastes, and some of the uncertainties will remain regardless of the time and expense in attempting to characterize the system and assess its performance.
Date: October 3, 2004
Creator: Isaacs, T.
System: The UNT Digital Library
The Optimum Plutonium Inert Matrix Fuel Form for Reactor-Based Plutonium Disposition (open access)

The Optimum Plutonium Inert Matrix Fuel Form for Reactor-Based Plutonium Disposition

The University of Florida has underway an ongoing research program to validate the economic, operational and performance benefits of developing an inert matrix fuel (IMF) for the disposition of the U.S. weapons plutonium (Pu) and for the recycle of reprocessed Pu. The current fuel form of choice for Pu disposition for the Department of Energy is as a mixed oxide (MOX) (PuO2/UO2). We will show analyses that demonstrate that a Silicon Carbide (SiC) IMF offers improved performance capabilities as a fuel form for Pu recycle and disposition. The reason that UF is reviewing various materials to serve as an inert matrix fuel is that an IMF fuel form can offer greatly reduced Pu and transuranic isotope (TRU) production and also improved thermal performance characteristics. Our studies showed that the Pu content is reduced by an order of magnitude while centerline fuel temperatures are reduced approximately 380 degrees centigrade compared to MOX. These reduced temperatures result in reduced stored heat and thermal stresses in the pellet. The reduced stored heat reduces the consequences of the loss of coolant accident, while the reduced temperatures and thermal stresses yield greatly improved fuel performance. Silicon Carbide is not new to the nuclear industry, being …
Date: October 3, 2004
Creator: Tulenko, J.S.; Wang, J. & Acosta, C.
System: The UNT Digital Library
Teaching Thermal Hydraulics & Numerical Methods: An Introductory Control Volume Primer (open access)

Teaching Thermal Hydraulics & Numerical Methods: An Introductory Control Volume Primer

This paper covers the basics of the implementation of the control volume method in the context of the Homogeneous Equilibrium Model (HEM)(T/H) code using the conservation equations of mass, momentum, and energy. This primer uses the advection equation as a template. The discussion will cover the basic equations of the control volume portion of the course in the primer, which includes the advection equation, numerical methods, along with the implementation of the various equations via FORTRAN into computer programs and the final result for a three equation HEM code and its validation.
Date: October 3, 2004
Creator: Lucas, D. Scott
System: The UNT Digital Library
The Influence of Coating Structure on Micromachine Stiction (open access)

The Influence of Coating Structure on Micromachine Stiction

We have clearly shown that the film morphology dictates the anti-stiction properties of FDTS coatings. Release stiction is not observed when ideal monolayer films are present but can be extensive when thicker aggregate structures are present. This finding is significant because it indicates that agglomerate formation during processing is a major source of irreproducible behavior when FDTS coatings are used to release micromachined parts. The results could also help explain why coatings that are aged at high. humidity start to stick to each other. (AFM results show that humid environments promote the formation of aggregates from monolayer films.) The reason why aggregate structures promote stiction is currently unknown. However, it appears that aggregates interfere with the ability of FDTS to form dense, well-ordered coatings under microstructures, leading to surfaces that are sufficiently hydrophilic to allow for release stiction via an attractive Laplace force during drying.
Date: October 3, 2000
Creator: Kushmerick, J. G.; Hankins, M. G.; De Boer, M. P.; Clews, P. J.; Carpick, R. W. & Bunker, B. C.
System: The UNT Digital Library
Industry Teams with National Laboratories to Develop a Predictive Model for Powder Pressing and Die Design (open access)

Industry Teams with National Laboratories to Develop a Predictive Model for Powder Pressing and Die Design

None
Date: October 3, 2000
Creator: Ewsuk, K. G.; Arguello, J. G., Jr.; Zeuch, D. H.; Farber, B.; Carinci, L.; Kaniuk, J. et al.
System: The UNT Digital Library
Craters produced on Al, Cu and Au by Ar cluster impacts. (open access)

Craters produced on Al, Cu and Au by Ar cluster impacts.

None
Date: October 3, 2000
Creator: Birtcher, R. C.; Matsuo, J. & Yamada, I.
System: The UNT Digital Library
Directional Shear Force Microscopy (open access)

Directional Shear Force Microscopy

None
Date: October 3, 2000
Creator: Burns, A. R. & Carpick, R. W.
System: The UNT Digital Library
Resists for next generation lithography (open access)

Resists for next generation lithography

Four Next Generation Lithographic options (EUV, x-ray, EPL, IPL) are compared against four current optical technologies (i-line, DUV, 193 nm, 157 nm) for resolution capabilities based on wavelength. As the wavelength of the incident radiation decreases, the nature of the interaction with the resist changes. At high energies, optical density is less sensitive to molecular structure then at 157 nm.
Date: October 3, 2001
Creator: Brainard, Robert L.; Barclay, George G.; Anderson, Erik H. & Ocola, Leonidas E.
System: The UNT Digital Library
New Methods for Measuring Performance of Monolithic Multi-Junction Solar Cells (open access)

New Methods for Measuring Performance of Monolithic Multi-Junction Solar Cells

None
Date: October 3, 2000
Creator: King, David L.; Hansen, Barry R.; Moore, Jeannette M. & Aiken, Daniel James
System: The UNT Digital Library
Report of the Working Group on precision measurements (open access)

Report of the Working Group on precision measurements

Precision measurements of electroweak quantities are carried out to test the Standard Model (SM). In particular, measurements of the top quark mass, m{sub top}, when combined with precise measurements of the W mass, M{sub W}, and the weak mixing angle, sin{sup 2} {bar {theta}}{sub W}, make it possible to derive indirect constraints on the Higgs boson mass, M{sub H}, via top quark and Higgs boson electroweak radiative corrections to M{sub W}. Comparison of these constraints on M{sub H} with the mass obtained from direct observation of the Higgs boson in future collider experiments will be an important test of the SM. In this report, the prospects for measuring the W parameters (mass and width) and the weak mixing angle in Run II are discussed, and a program for extracting the probability distribution function of M{sub H} is described.
Date: October 3, 2001
Creator: al., Raymond L. Brock et
System: The UNT Digital Library
Search for Leptoquark Pairs Decaying to nu nu + Jets in p pbar Collisions at {radical}s = 1.8 TeV (open access)

Search for Leptoquark Pairs Decaying to nu nu + Jets in p pbar Collisions at {radical}s = 1.8 TeV

None
Date: October 3, 2001
Creator: al., V. M. Abazov et
System: The UNT Digital Library
Sleuth: A quasi-model-independent search strategy for new physics (open access)

Sleuth: A quasi-model-independent search strategy for new physics

How can we search for new physics when we only vaguely know what it should look like? How can we perform an unbiased yet data-driven search? If we see apparently anomalous events in our data, how can we quantify their ''interestingness'' a posteriori? We present an analysis strategy (SLEUTH) that simultaneously addresses each of these questions, and we demonstrate its application to over thirty exclusive final states in data collected by D0 in Run I of the Fermilab Tevatron.
Date: October 3, 2001
Creator: Knuteson, Bruce O.
System: The UNT Digital Library
On The Electric Fields and Currents Produced by Induction Logging Instruments in Anisotropic Media (open access)

On The Electric Fields and Currents Produced by Induction Logging Instruments in Anisotropic Media

None
Date: October 3, 2000
Creator: Lu, X.; Alumbaugh, D. L. & Weiss, C. J.
System: The UNT Digital Library
Mechanism and processing dependence of biaxial texture development in magnesium oxide thin films grown by inclined-substrate deposition. (open access)

Mechanism and processing dependence of biaxial texture development in magnesium oxide thin films grown by inclined-substrate deposition.

None
Date: October 3, 2000
Creator: Chudzik, M. P.; Koritala, R.; Luo, L. P.; Miller, D. J.; Balachandran, U. & Kannewurf, C. R.
System: The UNT Digital Library
Threshold Assessment: Definition of Acceptable Sites as Part of Site Selection for the Japanese HLW Program (open access)

Threshold Assessment: Definition of Acceptable Sites as Part of Site Selection for the Japanese HLW Program

For the last ten years, the Japanese High-Level Nuclear Waste (HLW) repository program has focused on assessing the feasibility of a basic repository concept, which resulted in the recently published H12 Report. As Japan enters the implementation phase, a new organization must identify, screen and choose potential repository sites. Thus, a rapid mechanism for determining the likelihood of site suitability is critical. The threshold approach, described here, is a simple mechanism for defining the likelihood that a site is suitable given estimates of several critical parameters. We rely on the results of a companion paper, which described a probabilistic performance assessment simulation of the HLW reference case in the H12 report. The most critical two or three input parameters are plotted against each other and treated as spatial variables. Geostatistics is used to interpret the spatial correlation, which in turn is used to simulate multiple realizations of the parameter value maps. By combining an array of realizations, we can look at the probability that a given site, as represented by estimates of this combination of parameters, would be good host for a repository site.
Date: October 3, 2000
Creator: McKenna, S.A.; Wakasugi, Keiichiro; Webb, E.K.; Makino, Hitoshi; Ishihara, Yoshinao, Ijiri, Yuji; Sawada, Atsushi et al.
System: The UNT Digital Library