AB Initio Calculations of Elastic Constants of BCC V-NB System at High Pressures (open access)

AB Initio Calculations of Elastic Constants of BCC V-NB System at High Pressures

First-principles total energy calculation based on the exact muffin-tin orbital and full potential linear muffin-tin orbital methods were used to calculate the equation of state and shear elastic constants of bcc V, Nb, and the V{sub 95}Nb{sub 05} disordered alloy as a function of pressure up to 6 Mbar. We found a mechanical instability in C{sub 44} and a corresponding softening in C at pressures {approx} 2 Mbar for V. Both shear elastic constants show softening at pressures {approx} 0.5 Mbar for Nb. Substitution of 5 at. % of V with Nb removes the instability of V with respect to trigonal distortions in the vicinity of 2 Mbar pressure, but still leaves the softening of C{sub 44} in this pressure region. We argue that the pressure induced shear instability (softening) of V (Nb) originates from the electronic system and can be explained by a combination of the Fermi surface nesting, electronic topological transition, and band Jahn-Teller effect.
Date: May 2, 2005
Creator: Landa, A; Klepeis, J; Soderlind, P; Naumov, I; Velikokhatnyi, O; Vitos, L et al.
Object Type: Article
System: The UNT Digital Library
Aviation Security: Screener Training and Performance Measurement Strengthened, but More Work Remains (open access)

Aviation Security: Screener Training and Performance Measurement Strengthened, but More Work Remains

A letter report issued by the Government Accountability Office with an abstract that begins "The screening of airport passengers and their checked baggage is a critical component in securing our nation's commercial aviation system. Since May 2003, GAO has issued six products related to screener training and performance. This report updates the information presented in the prior products and incorporates results from GAO's survey of 155 Federal Security Directors--the ranking Transportation Security Administration (TSA) authority responsible for the leadership and coordination of TSA security activities at the nation's commercial airports. Specifically, this report addresses (1) actions TSA has taken to enhance training for passenger and checked baggage screeners and screening supervisors, (2) how TSA ensures that screeners complete required training, and (3) actions TSA has taken to measure and enhance screener performance in detecting threat objects."
Date: May 2, 2005
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Cation distribution in a Fe-bearing K-feldspar from Itrongay,Madagascar. A combined neutron- and X-ray single crystal diffractionstudy (open access)

Cation distribution in a Fe-bearing K-feldspar from Itrongay,Madagascar. A combined neutron- and X-ray single crystal diffractionstudy

We determined the cation distribution and ordering of Si, Al and Fe on the tetrahedral sites of a monoclinic low-sanidine from Itrongay, Madagascar, by combined neutron- and X-ray single-crystal diffraction. The cation distribution was determined by means of a simultaneous refinement using neutron- and X-ray data, as well as by combining scattering densities obtained from separate refinements with chemical data from a microprobe experiment. The two methods give the same results and show that Fe is fully ordered on T1, whereas Al shows a high degree of disorder. Based on this and previously published temperature-dependent X-ray data, we conclude that it is preferential ordering of Fe on T1 even at high temperature, rather than a high diffusion kinetics of Fe, which causes this asymmetry in ordering behavior between Al and Fe. The preferential ordering of Fe3+ relative to Al3+ in T1 is consistent with its 25 percent larger ionic radius.
Date: May 2, 2005
Creator: Ackermann, Sonia; Kunz, Martin; Armbruster, Thomas; Schefer,Jurg & Hanni, Henry
Object Type: Article
System: The UNT Digital Library
Comparison of Direct and Indirect Gas Reactor Brayton Systems for Nuclear Electric Space Propulsion (open access)

Comparison of Direct and Indirect Gas Reactor Brayton Systems for Nuclear Electric Space Propulsion

Gas reactor systems are being considered as candidates for use in generating power for the Prometheus-1 spacecraft, along with other NASA missions as part of the Prometheus program. Gas reactors offer a benign coolant, which increases core and structural materials options. However, the gas coolant has inferior thermal transport properties, relative to other coolant candidates such as liquid metals. This leads to concerns for providing effective heat transfer and for minimizing pressure drop within the reactor core. In direct gas Brayton systems, i.e. those with one or more Brayton turbines in the reactor cooling loop, the ability to provide effective core cooling and low pressure drop is further constrained by the need for a low pressure, high molecular weight gas, typically a mixture of helium and xenon. Use of separate primary and secondary gas loops, one for the reactor and one or more for the Brayton system(s) separated by heat exchanger(s), allows for independent optimization of the pressure and gas composition of each loop. The reactor loop can use higher pressure pure helium, which provides improved heat transfer and heat transport properties, while the Brayton loop can utilize lower pressure He-Xe. However, this approach requires a separate primary gas circulator …
Date: May 2, 2005
Creator: Postlehwait, M; DiLorenzo, P; Belanger, S & Ashcroft, J
Object Type: Article
System: The UNT Digital Library
Cruise Missile Defense (open access)

Cruise Missile Defense

Congress has expressed interest in cruise missile defense for years. Cruise missiles (CMs) are essentially unmanned attack aircraft — vehicles composed of an airframe, propulsion system, guidance system, and weapons payload. The Department of Defense is pursuing several initiatives that seek to improve capabilities against an unpredictable cruise missile threat. These initiatives compete for funding and congressional attention.
Date: May 2, 2005
Creator: Hichkad, Ravi R. & Bolkcom, Christopher
Object Type: Report
System: The UNT Digital Library
Determination of Plutonium Activity Concentrations and 240Pu/239Pu Atom Ratios in Brown Algae (Fucus distichus) Collected from Amchitka Island, Alaska. (open access)

Determination of Plutonium Activity Concentrations and 240Pu/239Pu Atom Ratios in Brown Algae (Fucus distichus) Collected from Amchitka Island, Alaska.

Plutonium-239 ({sup 239}Pu) and plutonium-240 ({sup 240}Pu) activity concentrations and {sup 240}Pu/{sup 239}Pu atom ratios are reported for Brown Algae (Fucus distichus) collected from the littoral zone of Amchitka Island (Alaska) and at a control site on the Alaskan peninsula. Plutonium isotope measurements were performed in replicate using Accelerator Mass Spectrometry (AMS). The average {sup 240}Pu/{sup 239}Pu atom ratio observed in dried Fucus d. collected from Amchitka Island was 0.227 {+-} 0.007 (n=5) and compares with the expected {sup 240}Pu/{sup 239}Pu atom ratio in integrated worldwide fallout deposition in the Northern Hemisphere of 0.1805 {+-} 0.0057 (Cooper et al., 2000). In general, the characteristically high {sup 240}Pu/{sup 239}Pu content of Fucus d. analyzed in this study appear to indicate the presence of a discernible basin-wide secondary source of plutonium entering the marine environment. Of interest to the study of plutonium source terms within the Pacific basin are reports of elevated {sup 240}Pu/{sup 239}Pu atom ratios in fallout debris from high-yield atmospheric nuclear tests conducted in the Marshall Islands during the 1950s (Diamond et al., 1960), the wide range of {sup 240}Pu/{sup 239}Pu atom ratio values (0.19 to 0.34) observed in sea water, sediments, coral and other environmental media from the …
Date: May 2, 2005
Creator: Hamilton, T F; Brown, T A; Marchetti, A A; Martinelli, R E & Kehl, S R
Object Type: Report
System: The UNT Digital Library
Dynamic force spectroscopy of parallel individual mucin1-antibody bonds (open access)

Dynamic force spectroscopy of parallel individual mucin1-antibody bonds

We used atomic force microscopy (AFM) to measure the binding forces between Mucin1 (MUC1) peptide and a single chain antibody fragment (scFv) selected from a scFv library screened against MUC1. This binding interaction is central to the design of the molecules for targeted delivery of radioimmunotherapeutic agents for prostate and breast cancer treatment. Our experiments separated the specific binding interaction from non-specific interactions by tethering the antibody and MUC1 molecules to the AFM tip and sample surface with flexible polymer spacers. Rupture force magnitude and elastic characteristics of the spacers allowed identification of the bond rupture events corresponding to different number of interacting proteins. We used dynamic force spectroscopy to estimate the intermolecular potential widths and equivalent thermodynamic off rates for mono-, bi-, and tri-valent interactions. Measured interaction potential parameters agree with the results of molecular docking simulation. Our results demonstrate that an increase of the interaction valency leads to a precipitous decline in the dissociation rate. Binding forces measured for mono and multivalent interactions match the predictions of a Markovian model for the strength of multiple uncorrelated bonds in parallel configuration. Our approach is promising for comparison of the specific effects of molecular modifications as well as for determination …
Date: May 2, 2005
Creator: Sulchek, T A; Friddle, R W; Langry, K; Lau, E; Albrecht, H; Ratto, T et al.
Object Type: Article
System: The UNT Digital Library
Ecuador: Political and Economic Situation and U.S. Relations (open access)

Ecuador: Political and Economic Situation and U.S. Relations

This report provides information about the Political and Economic Situation and U.S. Relations on Ecuador. Ecuador is an oil-producing country that has experienced ten years of political and economic stability.
Date: May 2, 2005
Creator: Ribando, Clare
Object Type: Report
System: The UNT Digital Library
Egypt-United States Relations (open access)

Egypt-United States Relations

This report includes information about Egypt/United States relations, issues in these relations, and information regarding the United States' foreign assistance to Egypt
Date: May 2, 2005
Creator: Mark, Clyde R.
Object Type: Report
System: The UNT Digital Library
European Union Enlargement (open access)

European Union Enlargement

On May 1, 2004, 10 states joined the European Union (EU), enlarging the Union to 25 members. The EU views the enlargement process as an historic opportunity to promote stability in Europe and further the integration of the continent by peaceful means. In addition to the 10 new members (Cyprus, the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia, and Slovenia), three other states — Bulgaria, Romania, and Croatia — hope to accede to the EU by 2007. Turkey is also a candidate and is expected to begin accession negotiations in 2005. Macedonia has also applied for EU membership.
Date: May 2, 2005
Creator: Archick, Kristin
Object Type: Report
System: The UNT Digital Library
The European Union in 2005 and Beyond (open access)

The European Union in 2005 and Beyond

The European Union (EU) experienced significant changes in 2004 as it enlarged from 15 to 25 members and continued work on a new constitutional treaty to institute internal reforms and further EU political integration. In 2005, the EU is expected to build on these efforts and seek to implement several recent foreign policy and defense initiatives. This report describes the current status of the EU’s “constitution,” EU enlargement, the EU’s evolving foreign and defense policies, and possible implications for U.S.-EU relations.
Date: May 2, 2005
Creator: Archick, Kristin
Object Type: Report
System: The UNT Digital Library
The European Union's "Constitution" (open access)

The European Union's "Constitution"

In June 2004, the European Union (EU) concluded work on a constitutional treaty that contains changes to the EU’s governing institutions and decision-making processes. This new “constitution” grew out of the 2002-2003 Convention on the Future of Europe and previous EU efforts to institute internal reforms ahead of the Union’s expansion from 15 members to 25 in May 2004. The “constitution” aims to enable a larger EU to operate effectively and prevent gridlock, but it must still be ratified by all member states before it enters into force. This report provides background information on the Convention and describes the EU “constitution,” its key provisions, next steps, and possible implications for the U.S.-EU relationship.
Date: May 2, 2005
Creator: Archick, Kristin
Object Type: Report
System: The UNT Digital Library
The Federal Networking and Information Technology Research and Development Program: Funding Issues and Activities (open access)

The Federal Networking and Information Technology Research and Development Program: Funding Issues and Activities

This report discusses federal funding for IT research and development. Proponents assert that federal support of IT R&D has produced positive outcomes for the country and played a crucial role in supporting long-term research into fundamental aspects of computing. Critics assert that the government, through its funding mechanisms, may be picking “winners and losers” in technological development, a role more properly residing with the private sector.
Date: May 2, 2005
Creator: Moloney Figliola, Patricia
Object Type: Report
System: The UNT Digital Library
Higgs Boson Resummation via Bottom-Quark Fusion. (open access)

Higgs Boson Resummation via Bottom-Quark Fusion.

The region of small transverse momentum in q{bar q} and gg-initiated processes must be studied in the framework of resummation to account for the large, logarithmically-enhanced contributions to physical observables. In this letter, we study resummed differential cross-sections for Higgs production via bottom-quark fusion. We find that the differential distribution peaks at approximately 15 GeV, a number of great experimental importance to measuring this production channel.
Date: May 2, 2005
Creator: Field, B.
Object Type: Article
System: The UNT Digital Library
Interior and Related Agencies: FY2006 Appropriations (open access)

Interior and Related Agencies: FY2006 Appropriations

This report is a guide to one of the regular appropriations bills that Congress considers each year.
Date: May 2, 2005
Creator: Vincent, Carol H. & Boren, Susan
Object Type: Report
System: The UNT Digital Library
International Food Aid:  U.S. and Other Donor Contributions (open access)

International Food Aid: U.S. and Other Donor Contributions

This report provides three indicators of the U.S. contribution to global food aid: (1) shipments of major donors compiled by the International Grains Council, (2) U.S. contributions to the United Nations World Food Program (WFP), and (3) the U.S. commitment under the Food Aid Convention (FAC).
Date: May 2, 2005
Creator: Hanrahan, Charles E. & Canada, Carol
Object Type: Report
System: The UNT Digital Library
Legislative Vetoes After Chadha (open access)

Legislative Vetoes After Chadha

None
Date: May 2, 2005
Creator: unknown
Object Type: Report
System: The UNT Digital Library
[Letter from Leonard Sullivan, Jr. to Anthony J. Principi - May 2, 2005] (open access)

[Letter from Leonard Sullivan, Jr. to Anthony J. Principi - May 2, 2005]

Letter from Leonard Sullivan, Jr. of NARPAC, Inc to BRAC chairman Anthony J. Principi regarding closing facilities in order to open up land for urban development.
Date: May 2, 2005
Creator: Sullivan, Leonard, Jr.
Object Type: Letter
System: The UNT Digital Library
[Letters from Mitchell Daniels, Jr. to Harold Gehman, Jr., James Hansen, and James T. Hill - May 2, 2005] (open access)

[Letters from Mitchell Daniels, Jr. to Harold Gehman, Jr., James Hansen, and James T. Hill - May 2, 2005]

Letters from Governor Mitchell Daniels, Jr. to Harold Gehman, Jr., James V. Hansen, and James T. Hill discussing Naval Support Activity Crane, a joint Navy-Army installation located in Southwestern Indiana.
Date: May 2, 2005
Creator: Daniels, Mitchell Elias, 1949-
Object Type: Letter
System: The UNT Digital Library
Libya (open access)

Libya

None
Date: May 2, 2005
Creator: Mark, Clyde R.
Object Type: Report
System: The UNT Digital Library
Modeling aerosol-cloud interactions with a self-consistent cloud scheme in a general circulation model (open access)

Modeling aerosol-cloud interactions with a self-consistent cloud scheme in a general circulation model

This paper describes a self-consistent prognostic cloud scheme that is able to predict cloud liquid water, amount and droplet number (N{sub d}) from the same updraft velocity field, and is suitable for modeling aerosol-cloud interactions in general circulation models (GCMs). In the scheme, the evolution of droplets fully interacts with the model meteorology. An explicit treatment of cloud condensation nuclei (CCN) activation allows the scheme to take into account the contributions to N{sub d} of multiple types of aerosol (i.e., sulfate, organic and sea-salt aerosols) and kinetic limitations of the activation process. An implementation of the prognostic scheme in the Geophysical Fluid Dynamics Laboratory (GFDL) AM2 GCM yields a vertical distribution of N{sub d} characteristic of maxima in the lower troposphere differing from that obtained through diagnosing N{sub d} empirically from sulfate mass concentrations. As a result, the agreement of model-predicted present-day cloud parameters with satellite measurements is improved compared to using diagnosed N{sub d}. The simulations with pre-industrial and present-day aerosols show that the combined first and second indirect effects of anthropogenic sulfate and organic aerosols give rise to a global annual mean flux change of -1.8 W m{sup -2} consisting of -2.0 W m{sup -2} in shortwave and …
Date: May 2, 2005
Creator: Ming, Y; Ramaswamy, V; Donner, L J; Phillips, V T; Klein, S A; Ginoux, P A et al.
Object Type: Article
System: The UNT Digital Library
Motor Fuels: Understanding the Factors That Influence the Retail Price of Gasoline (open access)

Motor Fuels: Understanding the Factors That Influence the Retail Price of Gasoline

A letter report issued by the Government Accountability Office with an abstract that begins "Few things generate more attention and anxiety among American consumers than the price of gasoline. Periods of price increases are accompanied by high levels of media attention and consumer questioning about the causes and impacts of the price changes. The most recent upsurge in prices is no exception. Between January 3 and April 11, 2005, gasoline prices increased nearly every week, and during this time the average U.S. price for regular unleaded gasoline jumped 50 cents per gallon, adding about $7.8 billion to consumers' total gasoline bill, or about $58 for each passenger car in the United States. Spending billions more on gasoline pinched consumer budgets, leaving less money available for other purchases. Beyond having concerns over price increases, consumers find it difficult to understand how prices can vary so much across the country or even from neighborhood to neighborhood. For example, consumers in San Francisco paid an average of $2.63 per gallon during the week of April 11, 2005, while consumers in Chicago paid $2.33 per gallon; in Denver, $2.25; in New York, $2.19; and in Houston, $2.12. Within the city of Washington, D.C., pump …
Date: May 2, 2005
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Offshoring (a.k.a. Offshore Outsourcing) and Job Insecurity Among U.S. Workers (open access)

Offshoring (a.k.a. Offshore Outsourcing) and Job Insecurity Among U.S. Workers

None
Date: May 2, 2005
Creator: Levine, Linda
Object Type: Report
System: The UNT Digital Library
Partial Closure Report for the Area 514 Treatment and Storage Facility (open access)

Partial Closure Report for the Area 514 Treatment and Storage Facility

The purpose of this partial closure report is to inform the Department of Toxic Substances Control (DTSC) of the status of final closure of the Area 514 Treatment and Storage Facility (Area 514) and fulfill the DTSC requirements to proceed with the implementation of the interim action. Area 514 is located at the Livermore main site of Lawrence Livermore National Laboratory (LLNL). LLNL is owned by the U.S. Department of Energy (DOE) and operated jointly by DOE and the University of California. LLNL received its permit to operate hazardous waste facilities from DTSC in 1997. The hazardous waste treatment and storage operations of Area 514 were transferred to a newly constructed complex, the Decontamination and Waste Treatment Facility (DWTF), in 2003. Once the DWTF was operational, the final closure of Area 514 began in accordance with the DTSC-approved closure plan in June 2004. Abri Environmental Engineering, Inc., was retained by LLNL to observe the A514 closure process and prepare this partial closure report and certification. Prior to closure, the configuration of the Area 514 Treatment and Storage Facility consisted of Building 514, the Area 514-1 Container Storage and Treatment unit, the Area 514-2 Container Storage Unit (CSU), the Area 514-3 …
Date: May 2, 2005
Creator: Abri, M
Object Type: Report
System: The UNT Digital Library