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329 Matching Results

Start Over Access Open Access Year 2011 Day 5th Language English

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Results: 1 - 24 of 329 next

(open access)

Improved resolution of hydrocarbon structures and constitutional isomers in complex mixtures using Gas Chromatography-Vacuum Ultraviolet-Mass Spectrometry (GC-VUV-MS) (Supplementary Info)

Understanding the composition of complex hydrocarbon mixtures is important for environmental studies in a variety of fields, but many prevalent compounds cannot be confidently identified using traditional gas chromatography-mass spectrometry (GC-MS) techniques. This work uses vacuum-ultraviolet (VUV) ionization to elucidate the structures of a traditionally"unresolved complex mixture" by separating components by GC retention time, tR, and mass-to-charge ratio, m/Q, which are used to determine carbon number, NC, and the number of rings and double bonds, NDBE. Constitutional isomers are resolved based on tR, enabling the most complete quantitative analysis to date of structural isomers in an environmentally-relevant hydrocarbon mixture. Unknown compounds are classified in this work by carbon number, degree of saturation, presence of rings, and degree of branching, providing structural constraints. The capabilities of this analysis are explored using diesel fuel, in which constitutional isomer distribution patterns are shown to be reproducible between carbon numbers and follow predictable rules. Nearly half of the aliphatic hydrocarbon mass is shown to be branched, suggesting branching is more important in diesel fuel than previously shown. The classification of unknown hydrocarbons and the resolution of constitutional isomers significantly improves resolution capabilities for any complex hydrocarbon mixture.

Date: September 5, 2011

Creator: Aerosol Dynamics Inc.,; Aerodyne Research, Inc.,; Tofwerk AG, Thun, Switzerland; Isaacman, Gabriel; Wilson, Kevin R.; Chan, Arthur W. H. et al.

Object Type: Article

System: The UNT Digital Library

(open access)

Trade Primer: Qs and As on Trade Concepts, Performance, and Policy

The 112th Congress has a full legislative and oversight agenda on international trade. The agenda may include considering legislation to implement pending free trade agreements with Panama, South Korea, and Colombia, enhanced enforcement of U.S. trade agreements, as well as oversight of the World Trade Organization's Doha Round and trade relations with China. This report provides information and context for many of these topics. The report is divided into four sections in a question-and-answer format: trade concepts, U.S. trade performance, formulation of U.S. trade policy, and trade and investment issues.

Date: January 5, 2011

Creator: Ahearn, Raymond J.

Object Type: Report

System: The UNT Digital Library

(open access)

QMDS: A File System Metadata Management Service Supporting a Graph Data Model-based Query Language

None

Date: December 5, 2011

Creator: Ames, S; Gokhale, M B & Maltzahn, C

Object Type: Article

System: The UNT Digital Library

(open access)

Final Report: Imaging of Buried Nanoscale Optically Active Materials

This is a final report covering work done at University of Maryland to develop a Ballistic Electron Emission Luminescence (BEEL) microscope. This technique was intended to examine the carrier transport and photon emission in deeply buried optically-active layers and thereby provide a means for materials science to unmask the detailed consequences of experimentally controllable growth parameters, such as quantum dot size, statistics and orientation, and defect density and charge recombination pathways.

Date: July 5, 2011

Creator: Appelbaum, Ian

Object Type: Report

System: The UNT Digital Library

(open access)

The Debt Limit: History and Recent Increases

This report discusses how the total debt of the federal government can increase, including an historical overview of debt limits, and how the current economic slowdown has led to higher deficits and thereby a series of debt limit increases, as well as legislation related to these increases.

Date: April 5, 2011

Creator: Austin, D. Andrew & Levit, Mindy R.

Object Type: Report

System: The UNT Digital Library

(open access)

Traumatic Brain Injury Among Veterans

Traumatic Brain Injury (TBI) has been defined as "an alteration in brain function, or other evidence of brain pathology, caused by an external force." In the general population, TBI results mainly from falls, motor vehicle/traffic accidents, assaults, and other instances in which the head is struck by or strikes against an object. In military service members, TBI may also result from improvised explosive devices, mortars, grenades, bullets, or mines.

Date: May 5, 2011

Creator: Bagalman, Erin

Object Type: Report

System: The UNT Digital Library

(open access)

Search for a Light Higgs Boson at BaBar

We search for evidence of a light Higgs boson (A{sup 0}) in the radiative decays of the narrow {Upsilon}(3S) resonance: {Upsilon}(3S) {yields} {gamma}A{sup 0}, where A{sup 0} {yields} invisible or A{sup 0} {yields} {mu}{sup +}{mu}{sup -}. Such an object appears in extensions of the Standard Model, where a light CP-odd Higgs boson naturally couples strongly to b-quarks. We find no evidence for such processes in a sample of 122 x 106 {Upsilon}(3S) decays collected by the BABAR collaboration at the PEP-II B-factory, and set 90% C.L. upper limits on the product of the branching fractions {Beta}({Upsilon}(3S) {yields} {gamma}A{sup 0}) x {Beta}(A{sup 0} {yields} invisible) at (0.7-31) x 10{sup -6} in the mass range mA{sup 0} {le} 7.8 GeV, and on the product {Beta}({Upsilon}(3S) {yields} {gamma}A{sup 0}) x {Beta}(A{sup 0} {yields} {mu}{sup +}{mu}{sup -}) at (0.25-5.2) x 10{sup -6} in the mass range 0.212 {le} mA{sup 0} {le} 9.3GeV. We also set a limit on the dimuon branching fraction of the recently discovered {eta}{sub b} meson {Beta}({eta}{sub b} {yields} {mu}{sup +}{mu}{sup -}) < 0.8% at 90% C.L. The results are preliminary.

Date: December 5, 2011

Creator: Banerjee, Swagato

Object Type: Article

System: The UNT Digital Library

(open access)

The Rambler (Fort Worth, Tex.), Vol. 94, No. 18, Ed. 1 Wednesday, October 5, 2011

Weekly student newspaper from Texas Wesleyan University in Fort Worth, Texas that includes campus and local news along with advertising.

Date: October 5, 2011

Creator: Banks, Shauna

Object Type: Newspaper

System: The Portal to Texas History

(open access)

Top-Off Injection and Higher Currents at the Stanford Synchrotron Radiation Lightsource

The Stanford Synchrotron Radiation Lightsource (SSRL) at the SLAC National Accelerator Laboratory is a 234 m circumference storage ring for 3 GeV electrons with its synchrotron radiation serving currently 13 beamlines with about 27 experimental stations. It operated for long time with 100 mA peak current provided by usually three injections per day. In July 2009, the maximum beam current was raised to 200 mA. Over the period from June 2009 to March 2010, Top-Off operation started at every beamline. Top-Off, i.e., the injection of electrons into the storage ring with injection stoppers open, is necessary for SSRL to reach its design current of 500 mA. In the future, the maximal power of the injection current will also soon be raised from currently 1.5 W to 5 W. The Radiation Protection Department at SLAC worked with SSRL on the specifications for the safety systems for operation with Top-Off injection and higher beam currents.

Date: April 5, 2011

Creator: Bauer, Johannes M.; Liu, James C.; Prinz, Alyssa A. & Rokni, Sayed H.

Object Type: Article

System: The UNT Digital Library

(open access)

Vibration Budget for SuperB

We present a vibration budget for the SuperB accelerator. We include ground motion data, motion sensitivity of machine components, and beam feedback system requirements. The SuperB accelerator design attains at least 50 times higher than current B-factories due to smaller beam sizes and a crabbed waist crossing angle scheme at the IP (interaction point). The beam size (1{sigma}) at the IP will be about 10 {micro}m (horizontal) by 40 nm (vertical). These small beam sizes will make the luminosity very sensitive to mechanical vibration and electrical noise. Relative vertical misalignment of the two beams at the IP by only 8 nm will result in a 1% reduction in luminosity. The corresponding horizontal alignment tolerance of is 250x looser (2 {micro}m). The vertical beam angle at the IP for a 1% luminosity loss is fairly loose at 200 {micro}rad, and the horizontal beam angle tolerance is looser still. We will focus on vertical beam position at the IP, since this presents the greatest alignment challenge. The values presented here are for a closed orbit with tunes near a half-integer in the SuperB v.12 lattice.

Date: April 5, 2011

Creator: Bertsche, K.; Wittmer, W.; Bolzon, B.; Brunetti, L.; Jeremie, A.; Esposito, M. et al.

Object Type: Article

System: The UNT Digital Library

(open access)

Intelligence Issues for Congress

None

Date: October 5, 2011

Creator: Best, Richard A. Jr.

Object Type: Report

System: The UNT Digital Library

(open access)

Intelligence Issues for Congress

None

Date: August 5, 2011

Creator: Best, Richard A. Jr.

Object Type: Report

System: The UNT Digital Library

(open access)

Intelligence Issues for Congress

To address the challenges facing the U.S. intelligence community in the 21st century, congressional and executive branch initiatives have sought to improve coordination among the different agencies and to encourage better analysis. In December 2004, the Intelligence Reform and Terrorism Prevention Act (P.L. 108-458) was signed, providing for a Director of National Intelligence (DNI) with substantial authorities to manage the national intelligence effort. The legislation also established a separate Director of the Central Intelligence Agency.

Date: May 5, 2011

Creator: Best, Richard A., Jr.

Object Type: Report

System: The UNT Digital Library

(open access)

Computational Needs for the Next Generation Electric Grid Proceedings

The April 2011 DOE workshop, 'Computational Needs for the Next Generation Electric Grid', was the culmination of a year-long process to bring together some of the Nation's leading researchers and experts to identify computational challenges associated with the operation and planning of the electric power system. The attached papers provide a journey into these experts' insights, highlighting a class of mathematical and computational problems relevant for potential power systems research. While each paper defines a specific problem area, there were several recurrent themes. First, the breadth and depth of power system data has expanded tremendously over the past decade. This provides the potential for new control approaches and operator tools that can enhance system efficiencies and improve reliability. However, the large volume of data poses its own challenges, and could benefit from application of advances in computer networking and architecture, as well as data base structures. Second, the computational complexity of the underlying system problems is growing. Transmitting electricity from clean, domestic energy resources in remote regions to urban consumers, for example, requires broader, regional planning over multi-decade time horizons. Yet, it may also mean operational focus on local solutions and shorter timescales, as reactive power and system dynamics (including …

Date: October 5, 2011

Creator: Birman, Kenneth; Ganesh, Lakshmi; Renessee, Robbert van; Ferris, Michael; Hofmann, Andreas; Williams, Brian et al.

Object Type: Article

System: The UNT Digital Library

(open access)

Gulf Petro Initiative

In this report, technologies for petroleum production and exploration enhancement in deepwater and mature fields are developed through basic and applied research by: (1) Designing new fluids to efficiently drill deepwater wells that can not be cost-effectively drilled with current technologies. The new fluids will be heavy liquid foams that have low-density at shallow dept to avoid formation breakdown and high density at drilling depth to control formation pressure. The goal of this project is to provide industry with formulations of new fluids for reducing casing programs and thus well construction cost in deepwater development. (2) Studying the effects of flue gas/CO{sub 2} huff n puff on incremental oil recovery in Louisiana oilfields bearing light oil. An artificial neural network (ANN) model will be developed and used to map recovery efficiencies for candidate reservoirs in Louisiana. (3) Arriving at a quantitative understanding for the three-dimensional controlled-source electromagnetic (CSEM) geophysical response of typical Gulf of Mexico hydrocarbon reservoirs. We will seek to make available tools for the qualitative, rapid interpretation of marine CSEM signatures, and tools for efficient, three-dimensional subsurface conductivity modeling.

Date: February 5, 2011

Creator: Boukadi, Fathi

Object Type: Report

System: The UNT Digital Library

(open access)

The Principle of Maximum Conformality

A key problem in making precise perturbative QCD predictions is the uncertainty in determining the renormalization scale of the running coupling {alpha}{sub s}({mu}{sup 2}). It is common practice to guess a physical scale {mu} = Q which is of order of a typical momentum transfer Q in the process, and then vary the scale over a range Q/2 and 2Q. This procedure is clearly problematic since the resulting fixed-order pQCD prediction will depend on the renormalization scheme, and it can even predict negative QCD cross sections at next-to-leading-order. Other heuristic methods to set the renormalization scale, such as the 'principle of minimal sensitivity', give unphysical results for jet physics, sum physics into the running coupling not associated with renormalization, and violate the transitivity property of the renormalization group. Such scale-setting methods also give incorrect results when applied to Abelian QED. Note that the factorization scale in QCD is introduced to match nonperturbative and perturbative aspects of the parton distributions in hadrons; it is present even in conformal theory and thus is a completely separate issue from renormalization scale setting. The PMC provides a consistent method for determining the renormalization scale in pQCD. The PMC scale-fixed prediction is independent of the …

Date: April 5, 2011

Creator: Brodsky, Stanley J & Giustino, Di

Object Type: Article

System: The UNT Digital Library

(open access)

New Physics at the LHC: A Les Houches Report. Physics at Tev Colliders 2007 - New Physics Working Group

We present a collection of signatures for physics beyond the standard model that need to be explored at the LHC. The signatures are organized according to the experimental objects that appear in the final state, and in particular the number of high p{sub T} leptons. Our report, which includes brief experimental and theoretical reviews as well as original results, summarizes the activities of the 'New Physics' working group for the 'Physics at TeV Colliders' workshop (Les Houches, France, 11-29 June, 2007).

Date: December 5, 2011

Creator: Brooijmans, Gustaaf H.; Delgado, A.; Dobrescu, Bogdan A.; Grojean, C.; Narain, Meenakshi; Alwall, Johan et al.

Object Type: Article

System: The UNT Digital Library

(open access)

Legal Standing Under the First Amendment's Establishment Clause

This report analyzes the constitutional issues associated with standing (a restraint on the power of federal courts to render decisions), specifically related to cases arising under the Establishment Clause of the First Amendment regarding religion. It provides a background on the doctrine of standing, including the U.S. Supreme Court's interpretation of various types of standing: standing to sue as a citizen, as a taxpayer, and on behalf of another party. It also examines the current standing rules related to the Establishment Clause.

Date: April 5, 2011

Creator: Brougher, Cynthia

Object Type: Report

System: The UNT Digital Library