Design and Performance of Capping Layers for EUV Multilayer Mirrors (open access)

Design and Performance of Capping Layers for EUV Multilayer Mirrors

The reflectance stability of multilayer coatings for extreme ultraviolet lithography (EUVL) in a commercial tool environment is of uttermost importance to ensure continuous exposures with minimum maintenance cost. We have made substantial progress in designing the protective capping layer coatings, understanding their performance and estimating their lifetimes based on accelerated electron beam and EUV exposure studies. Our current capping layer coatings have about 40 times longer lifetimes than Si-capped multilayer optics. Nevertheless, the lifetime of current Ru-capped multilayers is too short to satisfy commercial tool requirements and further improvements are essential.
Date: March 10, 2003
Creator: Bajt, S.; Chapman, H. N.; Nuygen, N.; Alameda, J.; Robinson, J. C.; Malinowski, M. et al.
System: The UNT Digital Library
The Role of Demand Response in Default Service Pricing (open access)

The Role of Demand Response in Default Service Pricing

Dynamic retail electricity pricing, especially real-time pricing (RTP), has been widely heralded as a panacea for providing much-needed demand response in electricity markets. However, in designing default service for competitive retail markets, demand response often appears to be an afterthought. But that may be changing as states that initiated customer choice in the past 5-7 years reach an important juncture in retail market design. Most states with retail choice established an initial transitional period, during which utilities were required to offer a default or ''standard offer'' generation service, often at a capped or otherwise administratively-determined rate. Many retail choice states have reached, or are nearing, the end of their transitional period and several states have adopted an RTP-type default service for large commercial and industrial (C&I) customers. Are these initiatives motivated by the desire to induce greater demand response, or is RTP being called upon to serve a different role in competitive markets? Surprisingly, we found that in most cases, the primary reason for adopting RTP as the default service was not to encourage demand response, but rather to advance policy objectives related to the development of competitive retail markets. However, we also find that, if efforts are made in …
Date: March 10, 2006
Creator: Barbose, Galen; Goldman, Chuck & Neenan, Bernie
System: The UNT Digital Library
Neutron Detection with Cryogenics and Semiconductors (open access)

Neutron Detection with Cryogenics and Semiconductors

The common methods of neutron detection are reviewed with special attention paid to the application of cryogenics and semiconductors to the problem. The authors' work with LiF- and boron-based cryogenic instruments is described as well as the use of CdTe and HgI{sub 2} for direct detection of neutrons.
Date: March 10, 2005
Creator: Bell, Z. W.; Carpenter, D. A.; Cristy, S. S. & Lamberti, V. E.
System: The UNT Digital Library
A human breast cell model of pre-invasive to invasive transition (open access)

A human breast cell model of pre-invasive to invasive transition

A crucial step in human breast cancer progression is the acquisition of invasiveness. There is a distinct lack of human cell culture models to study the transition from pre-invasive to invasive phenotype as it may occur 'spontaneously' in vivo. To delineate molecular alterations important for this transition, we isolated human breast epithelial cell lines that showed partial loss of tissue polarity in three-dimensional reconstituted-basement membrane cultures. These cells remained non-invasive; however, unlike their non-malignant counterparts, they exhibited a high propensity to acquire invasiveness through basement membrane in culture. The genomic aberrations and gene expression profiles of the cells in this model showed a high degree of similarity to primary breast tumor profiles. The xenograft tumors formed by the cell lines in three different microenvironments in nude mice displayed metaplastic phenotypes, including squamous and basal characteristics, with invasive cells exhibiting features of higher grade tumors. To find functionally significant changes in transition from pre-invasive to invasive phenotype, we performed attribute profile clustering analysis on the list of genes differentially expressed between pre-invasive and invasive cells. We found integral membrane proteins, transcription factors, kinases, transport molecules, and chemokines to be highly represented. In addition, expression of matrix metalloproteinases MMP-9,-13,-15,-17 was up regulated …
Date: March 10, 2008
Creator: Bissell, Mina J; Rizki, Aylin; Weaver, Valerie M.; Lee, Sun-Young; Rozenberg, Gabriela I.; Chin, Koei et al.
System: The UNT Digital Library
An Evaluation of Savings and Measure Persistence Fromretrocommissioning of Large Commercial Buildings (open access)

An Evaluation of Savings and Measure Persistence Fromretrocommissioning of Large Commercial Buildings

Commercial building retrocommissioning activity has increased in recent years. LBNL recently conducted a study of 8 participants in Sacramento Municipal Utility District's (SMUD) retrocommissioning program. We evaluated the persistence of energy savings and measure implementation, in an effort to identify and understand factors that affect the longevity of retrocommissioning benefits. The LBNL analysis looked at whole-building energy and the retrocommissioning measure implementation status, incorporating elements from previous work by Texas A&M University and Portland Energy Conservation Inc. When possible, adjustments due to newly discovered major end uses, occupancy patterns and 2001 energy crisis responses were included in the whole-building energy analysis. The measure implementation analysis categorized each recommended measure and tracked the measures to their current operational status. Results showed a 59% implementation rate of recommended measures. The whole-building energy analysis showed an aggregate electricity savings of approximately 10.5% in the second post-retrocommissioning year, diminishing to approximately 8% in the fourth year. Results also showed the 2001 energy crisis played a significant role in the post-retrocommissioning energy use at the candidate sites. When natural gas consumption was included in the analysis, savings were reduced slightly, showing the importance in considering interactive effects between cooling and heating systems. The cost effectiveness …
Date: March 10, 2004
Creator: Bourassa, Norman J.; Piette, Mary Ann & Motegi, Naoya
System: The UNT Digital Library
Mechanism of GEMS formation (open access)

Mechanism of GEMS formation

GEMS (glass with embedded metal and sulfides) in interplanetary dust particles (IDPs) were examined using 200 keV analytical transmission electron microscopy. The morphologies and crystallography of embedded relict grains reveal that GEMS are pseudomorphs formed by irradiation processing of crystals free-floating in space. Some GEMS retain a compositional and morphological ''memory'' of the crystal from which they formed. Pseudomorphism rules out condensation, annealing, flash heating, or shock melting as alternative mechanisms of GEMS formation. A significant and often dominant fraction of the atoms in GEMS were sputtered deposited from other grains. Therefore, a normal (solar) isotopic composition is not a reliable indicator of whether GEMS formed in the solar system or in presolar interstellar or circumstellar environments.
Date: March 10, 2004
Creator: Bradley, J P & Dai, Z R
System: The UNT Digital Library
Year of Birth Determination Using Radiocarbon Dating of Dental Enamel (open access)

Year of Birth Determination Using Radiocarbon Dating of Dental Enamel

Radiocarbon dating is typically an archaeological tool rather than a forensic one. Recently however, we have shown that the amount of radiocarbon present in tooth enamel, as a result of nuclear bomb testing during the cold war, is a remarkably accurate indicator of when a person is born. Enamel isolated from human teeth is processed to form graphite and carbon-14 ({sup 14}C) levels are measured using accelerator mass spectrometry. Since there is no turnover of enamel after it is formed, {sup 14}C levels in the enamel represent {sup 14}C levels in the atmosphere at the time of its formation. In this paper we describe the strategy used to determine the date of birth of an individual based on radiocarbon levels in tooth enamel, focusing on the methodology of this strategy. Year of birth information can significantly assist police investigators when the identity of a deceased individual is unknown. In such cases police will try to match particulars of the unidentified individual (which is often only gender and/or an estimate of age), with particulars from missing persons lists.
Date: March 10, 2009
Creator: Buchholz, B. A. & Spalding, K. L.
System: The UNT Digital Library
Nonlinear Magneto-Optical Rotation via Alignment-to-Orientation Conversion (open access)

Nonlinear Magneto-Optical Rotation via Alignment-to-Orientation Conversion

Nonlinear magneto-optical rotation (NMOR) is investigated at highlight powers where the rotation is significantly modified by AC Stark shifts. These shifts are shown to change the overall sign of rotation for closed F-->F+1 transitions as light power is increased. The effect is demonstrated by measurements in rubidium and density matrix calculations. The results are important for applications of nonlinear optical rotation such as sensitive magnetometry.
Date: March 10, 2000
Creator: Budker, D.; Kimball, D. F.; Rochester, S. M. & Yashchuk, V. V.
System: The UNT Digital Library
Kinetics of HMX and CP Decomposition and Their Extrapolation for Lifetime Assessment (open access)

Kinetics of HMX and CP Decomposition and Their Extrapolation for Lifetime Assessment

Decomposition kinetics are determined for HMX (nitramine octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) and CP (2-(5-cyanotetrazalato) pentaammine cobalt (III) perchlorate) separately and together. For high levels of thermal stress, the two materials decompose faster as a mixture than individually. This effect is observed both in high-temperature thermal analysis experiments and in long-term thermal aging experiments. An Arrhenius plot of the 10% level of HMX decomposition by itself from a diverse set of experiments is linear from 120 to 260 C, with an apparent activation energy of 165 kJ/mol. Similar but less extensive thermal analysis data for the mixture suggests a slightly lower activation energy for the mixture, and an analogous extrapolation is consistent with the amount of gas observed in the long-term detonator aging experiments, which is about 30 times greater than expected from HMX by itself for 50 months at 100 C. Even with this acceleration, however, it would take {approx}10,000 years to achieve 10% decomposition at {approx}30 C. Correspondingly, negligible decomposition is predicted by this kinetic model for a few decades aging at temperatures slightly above ambient. This prediction is consistent with additional sealed-tube aging experiments at 100-120 C, which are estimated to have an effective thermal dose greater than that from decades …
Date: March 10, 2005
Creator: Burnham, A K; Weese, R K & Andrzejewski, W J
System: The UNT Digital Library
Coalescence of Nanometer Silver Islands on Oxides Grown by Filtered Cathodic Arc Depostion (open access)

Coalescence of Nanometer Silver Islands on Oxides Grown by Filtered Cathodic Arc Depostion

This report talks about Coalescence of Nanometer Silver Islands on Oxides Grown by Filtered Cathodic Arc Depostion
Date: March 10, 2003
Creator: Byon, Eungsun; Oates, Thomas W.H. & Anders, Andre
System: The UNT Digital Library
Euler angles for G2 (open access)

Euler angles for G2

We provide a simple parameterization for the group G2, which is analogous to the Euler parameterization for SU(2). We show how to obtain the general element of the group in a form emphasizing the structure of the fibration of G2 with fiber SO(4) and base H, the variety of quaternionic subalgebras of octonions. In particular this allows us to obtain a simple expression for the Haar measure on G2. Moreover, as a by-product it yields a concrete realization and an Einstein metric for H.
Date: March 10, 2005
Creator: Cacciatori, Sergio; Cerchiai, Bianca Letizia; della Vedova,Alberto; Ortenzi, Giovanni & Scotti, Antonio
System: The UNT Digital Library
Growth and characterization of superconducting spinel oxide LiTi2O4 thin films (open access)

Growth and characterization of superconducting spinel oxide LiTi2O4 thin films

Epitaxial films of LiTi{sub 2}O{sub 4} on single crystalline substrates of MgAl{sub 2}O{sub 4}, MgO, and SrTiO{sub 3} provide model systems to systematically explore the effects of lattice strain and microstructural disorder on the superconducting state. Lattice strain that affects bandwidth gives rise to variations in the superconducting and normal state properties. Microstructural disorder, such as antiphase boundaries that give rise to Ti network disorder, reduces the critical temperature, and Ti network disorder combined with Mg interdiffusion lead to a much more dramatic effect on the superconducting state. Surface sensitive X-ray absorption spectroscopy has identified Ti to retain site symmetry and average valence of the bulk material regardless of film thickness.
Date: March 10, 2009
Creator: Chopdekar, R.V.; Wong, F.; Takamura, Y.; Arenholz, E. & Suzuki, Y.
System: The UNT Digital Library
21st Century Steam for Asteroid Mitigation (open access)

21st Century Steam for Asteroid Mitigation

The systematic requirements to divert an object on an earth-impacting course are developed relating the minimum velocity perturbation (both magnitude and direction) to the time available before impact. This, coupled with the accuracy to which orbits can be determined, restricts the time available for any mitigation technology to operate. Because nuclear energy densities are nearly a million times higher than those possible with chemical bonds, it is the most mass efficient means for storing delivering energy with today's technology. The question is how to most effectively apply that energy. This paper will examine the simple case of shattering the body, as well as a more controlled approach in which one or more small velocity increments divert a body. The optimal approach depends on the detailed circumstances, but in either case, already developed technology permits a successful diversion with a few years to decades of notice. The success of nuclear options on relatively short timescales permits consideration of other technologies that while not so well developed might be sufficiently improved to divert small (100 meter) bodies.
Date: March 10, 2004
Creator: Dearborn, D S
System: The UNT Digital Library
Documenting the Physical Universe:Preserving the Record of SLAC from 1962 to 2005 (open access)

Documenting the Physical Universe:Preserving the Record of SLAC from 1962 to 2005

Since 1905, Albert Einstein's ''miraculous year'', modern physics has advanced explosively. In 2005, the World Year of Physics, a session at the SAA Annual meeting discusses three institutional initiatives--Einstein's collected papers, an international geophysical program, and a research laboratory--to examine how physics and physicists are documented and how that documentation is being collected, preserved, and used. This paper provides a brief introduction to the research laboratory (SLAC), discusses the origins of the SLAC Archives and History Office, its present-day operations, and the present and future challenges it faces in attempting to preserve an accurate historical record of SLAC's activities.
Date: March 10, 2006
Creator: Deken, Jean Marie
System: The UNT Digital Library
Recent Results from the MINOS Experiment (open access)

Recent Results from the MINOS Experiment

MINOS is an accelerator neutrino oscillation experiment at Fermilab. An intense high energy neutrino beam is produced at Fermilab and sent to a near detector on the Fermilab site and also to a 5 kTon far detector 735 km away in the Soudan mine in northern Minnesota. The experiment has now had several years of running with millions of events in the near detector and hundreds of events recorded in the far detector. I will report on the recent results from this experiment which include precise measurement of |{Delta}m{sup 2}{sub 32}|, analysis of neutral current data to limit the component of sterile neutrinos and the search for {nu}{sub {mu}} {yields} {nu}{sub e} conversion. The focus will be on the analysis of data for {nu}{sub {mu}} {yields} {nu}{sub e} conversion. Using data from an exposure of 3.14 x 10{sup 20} protons on target, we have selected electron type events in both the near and the far detector. The near detector is used to measure the background which is extrapolated to the far detector. We have found 35 events in the signal region with a background expectation of 27 {+-} 5(stat) {+-} 2(syst). Using this observation we set a 90% C.L. limit …
Date: March 10, 2009
Creator: Diwan,M.V.
System: The UNT Digital Library
Electrode Materials with the Na0.44MnO2 Structure: Effect ofTitanium Substitution on Physical and Electrochemical Properties (open access)

Electrode Materials with the Na0.44MnO2 Structure: Effect ofTitanium Substitution on Physical and Electrochemical Properties

The physical and electrochemical properties of LixMnO2 and LixTi0.11Mn0.89O2 synthesized from precursors made by glycine-nitrate combustion (GNC) and solid-state synthesis methods (SS) are examined in this paper. The highest specific capacities in lithium cells are obtained for SS-LixMnO2 electrodes at low current densities, but GNC-LixTi0.11Mn0.89O2 electrodes show the best high rate performance. These results can be explained by changes in the voltage characteristics and differences in the particle morphologies induced by the Ti-substitution and synthesis method. Ti-substitution also results in a decrease in the electronic conductivity, but greatly improves the thermal properties and imparts dissolution resistance to the electrode. For these reasons, it is preferable to use LixTi0.11MnO0.89O2 in lithium battery configurations rather than LixMnO2. Suggestions for improving the electrochemical performance of the Ti-substituted variant are given based on the results described herein.
Date: March 10, 2008
Creator: Doeff, Marca M; Saint, Juliette A.; Doeff, Marca M & Wilcox, James D.
System: The UNT Digital Library
Strength and toughness of ceramic-metal composites prepared by reactive hot pressing (open access)

Strength and toughness of ceramic-metal composites prepared by reactive hot pressing

Metal-reinforced Al{sub 2}0{sub 3}-matrix composites were prepared using reactive hot pressing. The volume fraction of the reinforcing phase was controlled by the stoichiometry of the particular displacement reaction used. Dense Al{sub 2}0{sub 3}-Ni and Al{sub 2}O{sub 3}-Nb composites were fabricated using this technique. The best combination of strength, 610 MPa, and toughness, 12 MPam{sup 1/2}, was found for the Al{sub 2}O{sub 3}-Ni composites. Indentation cracks and fracture surfaces showed evidence of ductile deformation of the Ni phase. The Al{sub 2}O{sub 3}-Nb composites had high strength, but the toughness was lower than expected due to the poor bonding between the Nb and A1{sub 2}0{sub 3}phases.
Date: March 10, 2000
Creator: Ellerby, Donald T.; Loehman, Ronald E. & Fahrenholtz, William G.
System: The UNT Digital Library
CODE ACCEPTANCE OF A NEW JOINING TECHNOLOGY FOR STORAGE CONTAINMENTS [REISSUE] (open access)

CODE ACCEPTANCE OF A NEW JOINING TECHNOLOGY FOR STORAGE CONTAINMENTS [REISSUE]

One of the activities associated with cleanup throughout the Department of Energy (DOE) complex is packaging radioactive materials into storage containers. Much of this work will be performed in high-radiation environments requiring fully remote operations, for which existing, proven systems do not currently exist. These conditions require a process that is capable of producing acceptable (defect-free) welds on a consistent basis; the need to perform weld repair, under fully-remote operations, can be extremely costly and time consuming. Current closure-welding technologies (fusion welding) are not well suited for this application and will present risk to cleanup cost and schedule. To address this risk, Fluor and the Pacific Northwest National Laboratory (PNNL) are proposing that a new and emerging joining technology, Friction Stir Welding (FSW), be considered for this work. FSW technology has been demonstrated in other industries (aerospace and marine) to produce near flaw-free welds on a consistent basis. FSW is judged capable of providing the needed performance for fully-remote closure welding of containers for radioactive materials for the following reasons: FSW is a solid-state process; material is not melted. FSW does not produce the type of defects associated with fusion welding, e.g., solidification-induced porosity, cracking, and distortion due to weld …
Date: March 10, 2009
Creator: GR, CANNELL; GJ, GRANT & BE, HILL
System: The UNT Digital Library
Adaptive Optics at Lawrence Livermore National Laboratory (open access)

Adaptive Optics at Lawrence Livermore National Laboratory

Adaptive optics enables high resolution imaging through the atmospheric by correcting for the turbulent air's aberrations to the light waves passing through it. The Lawrence Livermore National Laboratory for a number of years has been at the forefront of applying adaptive optics technology to astronomy on the world's largest astronomical telescopes, in particular at the Keck 10-meter telescope on Mauna Kea, Hawaii. The technology includes the development of high-speed electrically driven deformable mirrors, high-speed low-noise CCD sensors, and real-time wavefront reconstruction and control hardware. Adaptive optics finds applications in many other areas where light beams pass through aberrating media and must be corrected to maintain diffraction-limited performance. We describe systems and results in astronomy, medicine (vision science), and horizontal path imaging, all active programs in our group.
Date: March 10, 2003
Creator: Gavel, D T
System: The UNT Digital Library
RTP as an Optional Service: It's Alive, But Is It Well? (open access)

RTP as an Optional Service: It's Alive, But Is It Well?

Economists have advocated for real-time pricing (RTP) of electricity on the basis of the gains in economic efficiency that would result from charging customers the contemporaneous marginal cost of supplying electricity instead of the average cost. In recent years, RTP has also become the subject of interest in a variety of policy contexts, including integrated resource planning initiatives, ongoing efforts to improve efficiency and reliability in competitive electricity markets, and implementation of default service in states with retail choice. Most experience with RTP has been as an optional service, that is, a self-selecting alternative to the standard utility service. By our count, approximately 70 utilities in the U.S. offered an optional RTP program at some point over the past 20 years. However, many programs are now defunct. In 2003, 47 utilities in the U.S. were still offering an optional RTP program, on either a pilot or permanent basis (see Figure 1). In addition, 10 utilities in states with retail choice currently offer RTP as the default service for large customers that are not under contract with a competitive supplier. Another two utilities have received regulatory approval to do so in the next few years. Although the results of a few …
Date: March 10, 2006
Creator: Goldman, Charles; Barbose, Galen & Neenan, Bernie
System: The UNT Digital Library
2005 Radiation Oncology Gordon Research Conference (open access)

2005 Radiation Oncology Gordon Research Conference

This Report is about the Gordon Research Conference on Radiation Oncology Which was held at Crowne Plazza
Date: March 10, 2006
Creator: Gray, Elizabeth L. Travis Nancy Ryan
System: The UNT Digital Library
Linear Scaling First-Principles Molecular Dynamics with Controlled Accuracy (open access)

Linear Scaling First-Principles Molecular Dynamics with Controlled Accuracy

In our quest for accurate linear scaling first-principles molecular dynamics methods for pseudopotential DFT calculations, we investigate the accuracy of real-space grid approaches, with finite differences and spherical localization regions. We examine how the positions of the localization centers affect the accuracy and the convergence rate of the optimization process. In particular we investigate the accuracy of the atomic forces computation compared to the standard O(N{sup 3}) approach. We show the exponential decay of the error on the energy and forces with the size of the localization regions for a variety of realistic physical systems. We propose a new algorithm to automatically adapt the localization centers during the ground state computation which allows for molecular dynamics simulations with diffusion processes. The combination of algorithms proposed lead to a genuine linear scaling First-Principles Molecular Dynamics method with controlled accuracy. We illustrate our approach with examples of microcanonical molecular dynamics with localized orbitals.
Date: March 10, 2004
Creator: Gygi, F. & Fattebert, J.
System: The UNT Digital Library
EXPLORATION OF BEAM FAULT SCENARIOS FOR THE SPALLATION NEUTRON SOURCE TARGET. (open access)

EXPLORATION OF BEAM FAULT SCENARIOS FOR THE SPALLATION NEUTRON SOURCE TARGET.

The Spallation Neutron Source (SNS) accelerator systems will provide a 1 GeV, 1.44 MW proton beam to a liquid mercury target for neutron production. In order to ensure adequate lifetime of the target system components, requirements on several beam parameters must be maintained. A series of error studies was performed to explore credible fault scenarios which can potentially violate the various beam-on-target parameters. The response of the beam-on-target parameters to errors associated with the phase-space painting process in the ring and field setpoint errors in all the ring-to-target beam transport line elements were explored and will be presented. The plan for ensuring beam-on-target parameters will also be described.
Date: March 10, 2004
Creator: HENDERSON,S. RAPARIA,D. FEDOTOV,A. LEE,Y. Y. WEI,J. ET AL.
System: The UNT Digital Library
COMPUTATIONAL STUDIES OF COLLECTIVE BEAM DYNAMICS IN HIGH INTENSITY RINGS. (open access)

COMPUTATIONAL STUDIES OF COLLECTIVE BEAM DYNAMICS IN HIGH INTENSITY RINGS.

Collective interactions of the beam with itself and with its periodic lattice surroundings in high intensity accelerator rings, such as PSR and SNS, can lead to beam growth, halo generation, and losses. These interactions also provide a rich source of dynamic phenomena for analytical, computational, and experimental study. With continuing increases in model development and computer power, a number of sophisticated codes are now capable of detailed realistic studies of collective beam dynamics in rings. We concentrate here on a computational examination of high intensity beam dynamics in SNS. These studies include the effects of the accelerator lattice, space charge, impedances, losses and collimation, and magnet errors.
Date: March 10, 2004
Creator: HOLMES,J. A. COUSINEAU,S. DANILOV,V. HENDERSON,S. SHISHLO,A. FEDOTOV,A.
System: The UNT Digital Library