13.2 nm Table-Top Inspection Microscope for Extreme Ultraviolet Lithography Mask Defect Characterization (open access)

13.2 nm Table-Top Inspection Microscope for Extreme Ultraviolet Lithography Mask Defect Characterization

We report on a reflection microscope that operates at 13.2-nm wavelength with a spatial resolution of 55{+-}3 nm. The microscope uses a table-top EUV laser to acquire images of photolithography masks in 20 seconds.
Date: April 7, 2009
Creator: Brizuela, F.; Wang, Y.; Brewer, C.; Pedaci, F.; Chao, W.; Anderson, E. et al.
Object Type: Article
System: The UNT Digital Library
2010 Census: Census Bureau Continues to Make Progress in Mitigating Risks to a Successful Enumeration, but Still Faces Various Challenges (open access)

2010 Census: Census Bureau Continues to Make Progress in Mitigating Risks to a Successful Enumeration, but Still Faces Various Challenges

Testimony issued by the Government Accountability Office with an abstract that begins "The decennial census is a constitutionally-mandated activity that produces data used to apportion congressional seats, redraw congressional districts, and help allocate billions of dollars in federal assistance. In March 2008, GAO designated the 2010 Census a high-risk area in part because of information technology (IT) shortcomings. The U.S. Census Bureau (Bureau) has since strengthened its risk management efforts and made other improvements; however, in March 2009, GAO noted that a number of challenges and uncertainties remained. This testimony discusses the Bureau's readiness for 2010 and covers: (1) the delivery of key IT systems, (2) preliminary findings on the results of address canvassing and the lessons learned from that operation that can be applied to subsequent field operations, and (3) the Bureau's progress in improving its cost estimation abilities. The testimony is based on previously issued and ongoing GAO work."
Date: October 7, 2009
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
5000 groove/mm multilayer-coated blazed grating with 33percent efficiency in the 3rd order in the EUV wavelength range (open access)

5000 groove/mm multilayer-coated blazed grating with 33percent efficiency in the 3rd order in the EUV wavelength range

We report on recent progress in developing diffraction gratings which can potentially provide extremely high spectral resolution of 105-106 in the EUV and soft x-ray photon energy ranges. Such a grating was fabricated by deposition of a multilayer on a substrate which consists ofa 6-degree blazed grating with a high groove density. The fabrication of the substrate gratings was based on scanning interference lithography and anisotropic wet etch of silicon single crystals. The optimized fabrication process provided precise control of the grating periodicity, and the grating groove profile, together with very short anti-blazed facets, and near atomically smooth surface blazed facets. The blazed grating coated with 20 Mo/Si bilayers demonstrated a diffraction efficiency in the third order as high as 33percent at an incidence angle of 11? and wavelength of 14.18 nm.
Date: July 7, 2009
Creator: Lawrence Berkeley National Laboratory. Advanced Light Source.
Object Type: Article
System: The UNT Digital Library
ACRF Instrumentation Status and Information April 2009 (open access)

ACRF Instrumentation Status and Information April 2009

The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following five sections: (1) new instrumentation in the process of being acquired and deployed, (2) field campaigns, (3) existing instrumentation and progress on improvements or upgrades, (4) proposed future instrumentation, and (5) Small Business Innovation Research instrument development.
Date: May 7, 2009
Creator: Voyles, JW
Object Type: Report
System: The UNT Digital Library
Added Value of Reliability to a Microgrid: Simulations of Three California Buildings (open access)

Added Value of Reliability to a Microgrid: Simulations of Three California Buildings

The Distributed Energy Resources Customer Adoption Model is used to estimate the value an Oakland nursing home, a Riverside high school, and a Sunnyvale data center would need to put on higher electricity service reliability for them to adopt a Consortium for Electric Reliability Technology Solutions Microgrid (CM) based on economics alone. A fraction of each building's load is deemed critical based on its mission, and the added cost of CM capability to meet it added to on-site generation options. The three sites are analyzed with various resources available as microgrid components. Results show that the value placed on higher reliability often does not have to be significant for CM to appear attractive, about 25 $/kWcdota and up, but the carbon footprint consequences are mixed because storage is often used to shift cheaper off-peak electricity to use during afternoon hours in competition with the solar sources.
Date: May 7, 2009
Creator: Marnay, Chris; Lai, Judy; Stadler, Michael & Siddiqui, Afzal
Object Type: Article
System: The UNT Digital Library
Advanced Gate Drive for the SNS High Voltage Converter Modulator (open access)

Advanced Gate Drive for the SNS High Voltage Converter Modulator

SLAC National Accelerator Laboratory is developing a next generation H-bridge switch plate [1], a critical component of the SNS High Voltage Converter Modulator [2]. As part of that effort, a new IGBT gate driver has been developed. The drivers are an integral part of the switch plate, which are essential to ensuring fault-tolerant, high-performance operation of the modulator. The redesigned driver improves upon the existing gate drive in several ways. The new gate driver has improved fault detection and suppression capabilities; suppression of shoot-through and over-voltage conditions, monitoring of dI/dt and Vce(sat) for fast over-current detection and suppression, and redundant power isolation are some of the added features. In addition, triggering insertion delay is reduced by a factor of four compared to the existing driver. This paper details the design and performance of the new IGBT gate driver. A simplified schematic and description of the construction are included. The operation of the fast over-current detection circuits, active IGBT over-voltage protection circuit, shoot-through prevention circuitry, and control power isolation breakdown detection circuit are discussed.
Date: May 7, 2009
Creator: Nguyen, M. N.; Burkhart, C.; Kemp, M. A. & Anderson, D. E.
Object Type: Article
System: The UNT Digital Library
Advanced Water-Gas Shift Membrane Reactor (open access)

Advanced Water-Gas Shift Membrane Reactor

The overall objectives for this project were: (1) to identify a suitable PdCu tri-metallic alloy membrane with high stability and commercially relevant hydrogen permeation in the presence of trace amounts of carbon monoxide and sulfur; and (2) to identify and synthesize a water gas shift catalyst with a high operating life that is sulfur and chlorine tolerant at low concentrations of these impurities. This work successfully achieved the first project objective to identify a suitable PdCu tri-metallic alloy membrane composition, Pd{sub 0.47}Cu{sub 0.52}G5{sub 0.01}, that was selected based on atomistic and thermodynamic modeling alone. The second objective was partially successful in that catalysts were identified and evaluated that can withstand sulfur in high concentrations and at high pressures, but a long operating life was not achieved at the end of the project. From the limited durability testing it appears that the best catalyst, Pt-Re/Ce{sub 0.333}Zr{sub 0.333}E4{sub 0.333}O{sub 2}, is unable to maintain a long operating life at space velocities of 200,000 h{sup -1}. The reasons for the low durability do not appear to be related to the high concentrations of H{sub 2}S, but rather due to the high operating pressure and the influence the pressure has on the WGS reaction …
Date: January 7, 2009
Creator: Emerson, Sean; Vanderspurt, Thomas; Opalka, Susanne; Radhakrishnan, Rakesh & Willigan, Rhonda
Object Type: Report
System: The UNT Digital Library
Afghanistan: Narcotics and U.S. Policy (open access)

Afghanistan: Narcotics and U.S. Policy

This report provides current statistical information, profiles the Afghanistan narcotics trade's participants, explores linkages between narcotics, insecurity, and corruption, and reviews U.S. and international policy responses since late 2001. The report also considers ongoing policy debates regarding the counternarcotics role of coalition military forces, poppy eradication, alternative livelihoods, and funding issues for Congress.
Date: October 7, 2009
Creator: Blanchard, Christopher M.
Object Type: Report
System: The UNT Digital Library
Agricultural Conservation Issues in the 111th Congress (open access)

Agricultural Conservation Issues in the 111th Congress

This report focuses on the discussions in the 111th Congress on the 2008 farm bill. Moreover, the report details that debate has shifted to the off-farm impact the bill has. The report also discusses the budgetary issues surrounding the farm bill that the 111th Congress was presented with.
Date: July 7, 2009
Creator: Stubbs, Megan
Object Type: Report
System: The UNT Digital Library
Air Force C-17 Aircraft Procurement: Background and Issues for Congress (open access)

Air Force C-17 Aircraft Procurement: Background and Issues for Congress

This report provides background information on the C-17 Aircraft program, including previous appropriations, related programs, and issues for Congress. The primary issue for Congress in FY2010 is whether to procure additional C-17s. An additional issue is whether to pass legislation relating to the airlift aircraft force structure. Congress's decisions on these issues could affect DOD capabilities and funding requirements and the U.S. military aircraft industrial base.
Date: October 7, 2009
Creator: O'Rourke, Ronald
Object Type: Report
System: The UNT Digital Library
Alert Systems for Missing Adults in Eleven States: Background and Issues for Congress (open access)

Alert Systems for Missing Adults in Eleven States: Background and Issues for Congress

This report discusses the emerging development of nationwide alert systems to recover missing adults, such as those with mental impairment (such as Alzheimer's disease), developmental disabilities, or suicidal tendencies. This report provides an overview of such alert systems in 11 states: Colorado, Delaware, Florida, Georgia, Kentucky, North Carolina, Ohio, Oklahoma, Rhode Island, Texas, and Virginia. This report also provides a discussion of issues for Congress to consider with respect to the federal role, if any, in developing state alert programs for missing adults.
Date: May 7, 2009
Creator: Fernandes, Adrienne L. & Colello, Kirsten J.
Object Type: Report
System: The UNT Digital Library
America Competes Act: NIST Applied Some Safeguards in Obtaining Expert Services, but Additional Direction from Congress Is Needed (open access)

America Competes Act: NIST Applied Some Safeguards in Obtaining Expert Services, but Additional Direction from Congress Is Needed

A letter report issued by the Government Accountability Office with an abstract that begins "The America COMPETES Act gave the National Institute of Standards and Technology (NIST), within the Department of Commerce, the authority, through 2010, to obtain the temporary services of up to 200 experts or consultants per year, but did not specify how the agency should acquire these services. NIST has used this authority to award personal services contracts to obtain the services of individuals. The act requires GAO to report on whether additional safeguards would be needed if NIST's authority were to be made permanent. To meet that requirement, GAO determined (1) the extent to which NIST has used its authority; (2) how effective the authority has been in helping NIST meet its need for experts; and (3) the extent to which NIST has provided appropriate safeguards over its use, and what additional safeguards are needed. GAO reviewed statutes, regulations, federal guidance, and NIST's contracts. In addition, GAO interviewed officials at NIST, Commerce, and the Office of Personnel Management (OPM)."
Date: August 7, 2009
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Anomalies and Discrete Chiral Symmetries (open access)

Anomalies and Discrete Chiral Symmetries

The quantum anomaly that breaks the U(1) axial symmetry of massless multi-flavored QCD leaves behind a discrete flavor-singlet chiral invariance. With massive quarks, this residual symmetry has a close connection with the strong CP-violating parameter theta. One result is that if the lightest quarks are degenerate, then a first order transition will occur when theta passes through pi. The resulting framework helps clarify when the rooting prescription for extrapolating in the number of flavors is valid.
Date: September 7, 2009
Creator: Creutz, M.
Object Type: Article
System: The UNT Digital Library
Area 5 Radioactive Waste Management Complex Administrative Boundary Survey (open access)

Area 5 Radioactive Waste Management Complex Administrative Boundary Survey

A package sent to the Bureau of Land Management containing a property description, a notice of intent to relinquish, aerial photos, and engineering drawings
Date: May 7, 2009
Creator: National Security Technologies, LLC
Object Type: Report
System: The UNT Digital Library
Assessing Treasury's Strategy: Six Months of TARP (open access)

Assessing Treasury's Strategy: Six Months of TARP

April report of the U.S. Congressional Oversight Panel describing their activities and findings regarding the federal government's current strategy in mitigating the effects of the 2007-2008 financial crisis through the Troubled Asset Relief Fund (TARP).
Date: April 7, 2009
Creator: United States. Congressional Oversight Panel.
Object Type: Report
System: The UNT Digital Library
ATPA Renewal: Background and Issues (open access)

ATPA Renewal: Background and Issues

This report outlines the various aspects of the Andean Trade Preference Act (ATPA), including significant dates and modifications. The ATPA extends special duty treatment to certain U.S. imports from Bolivia, Colombia, Ecuador, and Peru that meet domestic content and other requirements. The purpose of ATPA is to promote economic growth in the Andean region and to encourage a shift away from dependence on illegal drugs by supporting legitimate economic activities.
Date: August 7, 2009
Creator: Villarreal, M. A.
Object Type: Report
System: The UNT Digital Library
Aviation Security: DHS and TSA Have Researched, Developed, and Begun Deploying Passenger Checkpoint Screening Technologies, but Continue to Face Challenges (open access)

Aviation Security: DHS and TSA Have Researched, Developed, and Begun Deploying Passenger Checkpoint Screening Technologies, but Continue to Face Challenges

A letter report issued by the Government Accountability Office with an abstract that begins "Since fiscal year 2002, the Transportation Security Administration (TSA) and the Department of Homeland Security (DHS) have invested over $795 million in technologies to screen passengers at airport checkpoints. The DHS Science and Technology Directorate (S&T) is responsible, with TSA, for researching and developing technologies, and TSA deploys them. GAO was asked to evaluate the extent to which (1) TSA used a risk-based strategy to prioritize technology investments; (2) DHS researched, developed, and deployed new technologies, and why deployment of the explosives trace portal (ETP) was halted; and (3) DHS coordinated research and development efforts with key stakeholders. To address these objectives, GAO analyzed DHS and TSA plans and documents, conducted site visits to research laboratories and nine airports, and interviewed agency officials, airport operators, and technology vendors."
Date: October 7, 2009
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
BaBrI:Eu2 + , a new bright scintillator (open access)

BaBrI:Eu2 + , a new bright scintillator

The scintillation properties of BaBrI:Eu2+ are reported. Crystals were produced by the vertical Bridgman technique in a sealed quartz ampoule. Excellent scintillation properties were measured. A light yield of 81,0007 +- 3000 photons per MeV (ph/MeV) of absorbed gamma-ray energy was measured. An energy resolution (FWHM over peak position) of 4.870.5percent was observed for the 662keV full absorption peak. Pulsed X-ray luminescence measurements show two exponential decay components of 297 and 482 ns with a contribution to the total light output of 23percent and 77percent, respectively. Under X-ray and UV excitation, the emission corresponds to a broadband center at 413 nm. These initial values make BaBrI:Eu2+ one of the brightest and the fastest known Eu2+ doped scintillators.
Date: November 7, 2009
Creator: Bourret-Courchesne, E.D.; Bizarri, G.; Hanrahan, S.M.; Gundiah, G.; Yan, Z. & Derenzo, S.E.
Object Type: Article
System: The UNT Digital Library
Binary pseudo-random gratings and arrays for calibration of the modulation transfer function of surface profilometers: recent developments (open access)

Binary pseudo-random gratings and arrays for calibration of the modulation transfer function of surface profilometers: recent developments

The major problem of measurement of a power spectral density (PSD) distribution of the surface heights with surface profilometers arises due to the unknown Modulation Transfer Function (MTF) of the instruments. The MTF tends to distort the PSD at higher spatial frequencies. It has been suggested [Proc. SPIE 7077-7, (2007), Opt. Eng. 47 (7), 073602-1-5 (2008)] that the instrumental MTF of a surface profiler can be precisely measured using standard test surfaces based on binary pseudo-random (BPR) patterns. In the cited work, a one dimensional (1D) realization of the suggested method based on use of BPR gratings has been demonstrated. Here, we present recent achievements made in fabricating and using two-dimensional (2D) BPR arrays that allow for a direct 2D calibration of the instrumental MTF. The 2D BPRAs were used as standard test surfaces for 2D MTF calibration of the MicromapTM-570 interferometric microscope with all available objectives. The effects of fabrication imperfections on the efficiency of calibration are also discussed.
Date: July 7, 2009
Creator: Barber, Samuel K.; Soldate, Paul; Anderson, Erik H.; Cambie, Rossana; Marchesini, Stefano; McKinney, Wanye R. et al.
Object Type: Article
System: The UNT Digital Library
Biosafety Laboratories: BSL-4 Laboratories Improved Perimeter Security Despite Limited Action by CDC (open access)

Biosafety Laboratories: BSL-4 Laboratories Improved Perimeter Security Despite Limited Action by CDC

A letter report issued by the Government Accountability Office with an abstract that begins "Biosafety laboratories are primarily regulated by either the Department of Health and Human Services (HHS) or the U.S. Department of Agriculture (USDA), depending on whether the substances they handle pose a threat to the health of humans or plants, animals, and related products, respectively. Currently, all operational biosafety level 4 (BSL-4) labs are overseen by HHS's Centers for Disease Control and Prevention (CDC). BSL-4 labs handle the world's most dangerous agents and toxins that cause incurable and deadly diseases. In September 2008, GAO reported that two of the five operational BSL-4 labs had less than a third of the key perimeter security controls GAO assessed and recommended that CDC implement specific perimeter controls for all BSL-4 labs. GAO was asked to (1) provide an update on what action, if any, CDC took to address the 2008 recommendation; (2) determine whether perimeter security controls at the two deficient BSL-4 labs had improved since the 2008 report; and (3) provide other observations about the BSL-4 labs it assessed. To meet these objectives, GAO reviewed CDC's statement to Congress as well as other agency and HHS documentation on actions …
Date: July 7, 2009
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
California Drought: Hydrological and Regulatory Water Supply Issues (open access)

California Drought: Hydrological and Regulatory Water Supply Issues

This report discusses California's current hydrological situation and provides background on regulatory restrictions affecting California water deliveries, as well as on the long-established state water rights system, which also results in uneven water deliveries in times of shortages.
Date: December 7, 2009
Creator: Cody, Betsy A.; Folger, Peter & Brougher, Cynthia
Object Type: Report
System: The UNT Digital Library
Causticizing for Black Liquor Gasifiers (open access)

Causticizing for Black Liquor Gasifiers

The cost-benefit outlook of black liquor gasification (BLG) could be greatly improved if the smelt causticization step could be achieved in situ during the gasification step. Or, at a minimum, the increase in causticizing load associated with BLG could be mitigated. A number of chemistries have been proven successful during black liquor combustion. In this project, three in situ causticizing processes (titanate, manganate, and borate) were evaluated under conditions suitable for high temperature entrained flow BLG, and low temperature steam reforming of black liquor. The evaluation included both thermodynamic modeling and lab experimentation. Titanate and manganate were tested for complete direct causticizing (to thus eliminate the lime cycle), and borates were evaluated for partial causticizing (to mitigate the load increase associated with BLG). Criteria included high carbonate conversion, corresponding hydroxide recovery upon hydrolysis, non process element (NPE) removal, and economics. Of the six cases (three chemistries at two BLG conditions), only two were found to be industrially viable: titanates for complete causticizing during high temperature BLG, and borates for partial causticizing during high temperature BLG. These two cases were evaluated for integration into a gasification-based recovery island. The Larsen [28] BLG cost-benefit study was used as a reference case for …
Date: January 7, 2009
Creator: Sinquefeld, Scott; Cantrell, James; Zeng, Xiaoyan; Ball, Alan & Empie, Jeff
Object Type: Report
System: The UNT Digital Library
Cellulose Synthesizing Complexes in Vascular Plants and Procaryotes (open access)

Cellulose Synthesizing Complexes in Vascular Plants and Procaryotes

Continuing the work initiated under DE-FG03-94ER20145, the following major accomplishments were achieved under DE-FG02-03ER15396 from 2003-2007: (a) we purified the acsD gene product of the Acetobacter cellulose synthase operon as well as transferred the CesA cellulose gene from Gossypium into E. coli in an attempt to crystallize this protein for x-ray diffraction structural analysis; however, crystallization attempts proved unsuccessful; (b) the Acetobacter cellulose synthase operon was successfully incorporated into Synechococcus, a cyanobacterium2; (c) this operon in Synechococcus was functionally expressed; (d) we successfully immunolabeled Vigna cellulose and callose synthase components and mapped their distribution before and after wounding; (e) we developed a novel method to produce replicas of cellulose synthases in tobacco BY-2 cells, and we demonstrated the cytoplasmic domain of the rosette TC; (f) from the moss Physcomitrella, we isolated two full-length cDNA sequences of cellulose synthase (PpCesA1 and PpCesA2) and attempted to obtain full genomic DNA sequences; (g) we examined the detailed molecular structure of a new form of non-crystalline cellulose known as nematic ordered cellulose (=NOC)3.
Date: July 7, 2009
Creator: Brown, Richard M., Jr. & Saxena, Inder Mohan
Object Type: Report
System: The UNT Digital Library
Chemical reactions of water molecules on Ru(0001) induced by selective excitation of vibrational modes (open access)

Chemical reactions of water molecules on Ru(0001) induced by selective excitation of vibrational modes

Tunneling electrons in a scanning tunneling microscope were used to excite specific vibrational quantum states of adsorbed water and hydroxyl molecules on a Ru(0 0 0 1) surface. The excited molecules relaxed by transfer of energy to lower energy modes, resulting in diffusion, dissociation, desorption, and surface-tip transfer processes. Diffusion of H{sub 2}O molecules could be induced by excitation of the O-H stretch vibration mode at 445 meV. Isolated molecules required excitation of one single quantum while molecules bonded to a C atom required at least two quanta. Dissociation of single H{sub 2}O molecules into H and OH required electron energies of 1 eV or higher while dissociation of OH required at least 2 eV electrons. In contrast, water molecules forming part of a cluster could be dissociated with electron energies of 0.5 eV.
Date: May 7, 2009
Creator: Mugarza, Aitor; Shimizu, Tomoko K.; Ogletree, D. Frank & Salmeron, Miquel
Object Type: Article
System: The UNT Digital Library