The universal criterion for switching a magnetic vortex core in soft magnetic nanodots (open access)

The universal criterion for switching a magnetic vortex core in soft magnetic nanodots

The universal criterion for ultrafast vortex core switching between core-up and -down vortex bi-states in soft magnetic nanodots was empirically investigated by micromagnetic simulations and combined with an analytical approach. Vortex-core switching occurs whenever the velocity of vortex core motion reaches a critical value, which is {nu}{sub c} = 330 {+-} 37 m/s for Permalloy, as estimated from numerical simulations. This critical velocity was found to be {nu}{sub c} = {eta}{sub c}{gamma} {radical}A{sub ex} with A{sub ex} the exchange stiffness, {gamma} the gyromagnetic ratio, and an estimated proportional constant {eta}{sub c} = 1.66 {+-} 0.18. This criterion does neither depend on driving force parameters nor on the dimension or geometry of the magnetic specimen. The phase diagrams for the vortex core switching criterion and its switching time with respect to both the strength and angular frequency of circular rotating magnetic fields were derived, which offer practical guidance for implementing vortex core switching into future solid state information storage devices.
Date: October 1, 2008
Creator: Lee, K. S.; Kim, S. K.; Yu, Y. S.; Choi, Y. S.; Guslienko, K. Y.; Jung, H. et al.
Object Type: Article
System: The UNT Digital Library
Peer review of the National Transportation Safety Board structural analysis of the I-35W bridge collapse. (open access)

Peer review of the National Transportation Safety Board structural analysis of the I-35W bridge collapse.

The Engineering Sciences Center at Sandia National Laboratories provided an independent peer review of the structural analysis supporting the National Transportation Safety Board investigation of the August 1, 2007 collapse of the I-35W Bridge in Minneapolis. The purpose of the review was to provide an impartial critique of the analysis approach, assumptions, solution techniques, and conclusions. Subsequent to reviewing numerous supporting documents, a SNL team of staff and management visited NTSB to participate in analysis briefings, discussions with investigators, and examination of critical elements of the bridge wreckage. This report summarizes the opinion of the review team that the NTSB analysis effort was appropriate and provides compelling supporting evidence for the NTSB probable cause conclusion.
Date: October 1, 2008
Creator: Gwinn, Kenneth West; Redmond, James Michael & Wellman, Gerald William
Object Type: Report
System: The UNT Digital Library
Top Quark Pair Production Cross Section and Forward-Backward Asymmetry at the Tevatron (open access)

Top Quark Pair Production Cross Section and Forward-Backward Asymmetry at the Tevatron

We present recent results on top quark pair production cross section and forward-backward asymmetry at the Tevatron. Three new cross section measurements from CDF and one new measurement from DO are presented that utilize the full dataset available. A new DO top cross section combination gives a ttbar production cross section of sigma ttbar = 7.83 + 0.46-0.45 (stat) + 0.64-0.53 (syst) +-0.48 (lumi). The new CDF cross section combination for ttbar production is found to be 7.0 +- 0.3 (stat) +- 0.4 (syst) +- 0.4 (lumi) pb giving a total uncertainty of 9%, very close to the that of the current best theoretical predictions. It is important to measure the top cross section in as many different channels as possible and investigate their compatibility. This is useful as new physics might show up differently in the different channels. Thus any significant discrepancy could be a sign of new physics. Three new measurements of the forward-backward asymmetry are also presented. The two CDF measurements unfold the observed asymmetry back to parton level in order to directly compare the values obtained with theoretical predictions. The DO measurement is not unfolded and therefore does not depend on the specific method used for …
Date: October 1, 2008
Creator: Lister, Alison
Object Type: Article
System: The UNT Digital Library
Air, Thermal and Water Management for PEM Fuel Cell Systems (open access)

Air, Thermal and Water Management for PEM Fuel Cell Systems

Document discussing the management of different properties of the PEM fuel cells.
Date: October 1, 2008
Creator: Liu, Mark K. Gee Chung
Object Type: Article
System: The UNT Digital Library
Economic Benefits, Carbon Dioxide (CO2) Emissions Reductions, and Water Conservation Benefits from 1,000 Megawatts (MW) of New Wind Power in Nevada (Fact Sheet) (open access)

Economic Benefits, Carbon Dioxide (CO2) Emissions Reductions, and Water Conservation Benefits from 1,000 Megawatts (MW) of New Wind Power in Nevada (Fact Sheet)

The U.S. Department of Energy?s Wind Powering America Program is committed to educating state-level policymakers and other stakeholders about the economic, CO2 emissions, and water conservation impacts of wind power. This analysis highlights the expected impacts of 1000 MW of wind power in Nevada. Although construction and operation of 1000 MW of wind power is a significant effort, six states have already reached the 1000-MW mark. We forecast the cumulative economic benefits from 1000 MW of development in Nevada to be $1.1 billion, annual CO2 reductions are estimated at 2.3 million tons, and annual water savings are 944 million gallons.
Date: October 1, 2008
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Data validation and security for reprocessing. (open access)

Data validation and security for reprocessing.

Next generation nuclear fuel cycle facilities will face strict requirements on security and safeguards of nuclear material. These requirements can result in expensive facilities. The purpose of this project was to investigate how to incorporate safeguards and security into one plant monitoring system early in the design process to take better advantage of all plant process data, to improve confidence in the operation of the plant, and to optimize costs. An existing reprocessing plant materials accountancy model was examined for use in evaluating integration of safeguards (both domestic and international) and security. International safeguards require independent, secure, and authenticated measurements for materials accountability--it may be best to design stand-alone systems in addition to domestic safeguards instrumentation to minimize impact on operations. In some cases, joint-use equipment may be appropriate. Existing domestic materials accountancy instrumentation can be used in conjunction with other monitoring equipment for plant security as well as through the use of material assurance indicators, a new metric for material control that is under development. Future efforts will take the results of this work to demonstrate integration on the reprocessing plant model.
Date: October 1, 2008
Creator: Tolk, Keith Michael; Merkle, Peter Benedict; DurÔan, Felicia Angelica & Cipiti, Benjamin B.
Object Type: Report
System: The UNT Digital Library
Addendum to the Closure Report for Corrective Action Unit 271: Areas 25, 26, and 27 Septic Systems Nevada Test Site, Nevada, Revision 0 (open access)

Addendum to the Closure Report for Corrective Action Unit 271: Areas 25, 26, and 27 Septic Systems Nevada Test Site, Nevada, Revision 0

This document constitutes an addendum to the August 2004, Closure Report for Corrective Action Unit 271, Areas 25, 26, and 27 Septic Systems as described in the document Recommendations and Justifications for Modifications for Use Restrictions Established under the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office Federal Facility Agreement and Consent Order (UR Modification document) dated February 2008. The UR Modification document was approved by NDEP on February 26, 2008. The approval of the UR Modification document constituted approval of each of the recommended UR modifications. In conformance with the UR Modification document, this addendum consists of: • This cover page that refers the reader to the UR Modification document for additional information • The cover and signature pages of the UR Modification document • The NDEP approval letter • The corresponding section of the UR Modification document This addendum provides the documentation justifying the modification of the UR for CAS 27-05-02, Leachfield. This UR was established as part of a Federal Facility Agreement and Consent Order (FFACO) corrective action and is based on the presence of contaminants at concentrations greater than the action levels established at the time of the initial investigation (FFACO, 1996; as …
Date: October 1, 2008
Creator: Kidman, Lynn
Object Type: Report
System: The UNT Digital Library
Lucasfilm, Save Energy Now (SEN) Data Center Assessment Summary (open access)

Lucasfilm, Save Energy Now (SEN) Data Center Assessment Summary

This assessment summary describes how the industrial Technologies Program helped Lucasfilm to find ways to improve the efficiency of its data center by performing a Save Energy Now energy assessment.
Date: October 1, 2008
Creator: unknown
Object Type: Report
System: The UNT Digital Library
State of the States 2008: Renewable Energy Development and the Role of Policy (open access)

State of the States 2008: Renewable Energy Development and the Role of Policy

This report provides insights into the status of renewable energy development at the state level. Renewable resources are increasing in development overall, but state development varies by resource and rates of change. The factors contributing to renewable energy development at the state level are identified and discussed, including the challenges of understanding the role of different factors in development. The report also compiles and evaluates the status of 'best practice' state policy design and connects the existence of some policies with increased renewable energy development through correlation analysis. The report also proposes a strategy for better understanding the role of policy in renewable energy development, based on market-transformation principles. Correlation analysis illustrates the potential for further application of these principles to renewable energy. The final section provides resources for state policy makers for better understanding and developing renewable energy resources.
Date: October 1, 2008
Creator: Brown, E. & Busche, S.
Object Type: Report
System: The UNT Digital Library
Future of Wind Energy Technology in the United States (open access)

Future of Wind Energy Technology in the United States

This paper describes the status of wind energy in the United States as of 2007, its cost, the potential for growth, offshore development, and potential technology improvements.
Date: October 1, 2008
Creator: Thresher, R.; Robinson, M. & Veers, P.
Object Type: Article
System: The UNT Digital Library
Economic Benefits, Carbon Dioxide (CO2) Emissions Reductions, and Water Conservation Benefits from 1,000 Megawatts (MW) of New Wind Power in West Virginia (Fact Sheet) (open access)

Economic Benefits, Carbon Dioxide (CO2) Emissions Reductions, and Water Conservation Benefits from 1,000 Megawatts (MW) of New Wind Power in West Virginia (Fact Sheet)

The U.S. Department of Energy?s Wind Powering America Program is committed to educating state-level policymakers and other stakeholders about the economic, CO2 emissions, and water conservation impacts of wind power. This analysis highlights the expected impacts of 1000 MW of wind power in West Virginia. Although construction and operation of 1000 MW of wind power is a significant effort, six states have already reached the 1000-MW mark. We forecast the cumulative economic benefits from 1000 MW of development in West Virginia to be $1.0 billion, annual CO2 reductions are estimated at 3.3 million tons, and annual water savings are 1,763 million gallons.
Date: October 1, 2008
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Search for New Physics in the B0(s) mixing phase (open access)

Search for New Physics in the B0(s) mixing phase

The Collider Detector at Fermilab (CDF) experiment performed the first measurement of the time-evolution of flavor-tagged B{sub s}{sup 0} {yields} J/{psi}{phi} decays, which probes mixing-induced CP-violation in the B{sub s}{sup 0} sector. Any sizable deviation from zero of the phase {beta}{sub s}J/{psi}{phi}, accessible through interference of the {bar b} {yields} {bar c}c{bar s} quark-level process accompanied or not by B{sub s}{sup 0}-{bar B}{sub s}{sup 0} mixing, would be unambiguous indication of physics beyond the Standard Model. I report CDF results obtained in 1.35 fb{sup -1}, a recent extension to a larger dataset corresponding to 2.8 fb{sup -1}, and future projections.
Date: October 1, 2008
Creator: Tonelli, Diego
Object Type: Article
System: The UNT Digital Library
Microfabricated wire arrays for Z-pinch. (open access)

Microfabricated wire arrays for Z-pinch.

Microfabrication methods have been applied to the fabrication of wire arrays suitable for use in Z. Self-curling GaAs/AlGaAs supports were fabricated as an initial route to make small wire arrays (4mm diameter). A strain relief structure that could be integrated with the wire was designed to allow displacements of the anode/cathode connections in Z. Electroplated gold wire arrays with integrated anode/cathode bus connections were found to be sufficiently robust to allow direct handling. Platinum and copper plating processes were also investigated. A process to fabricate wire arrays on any substrate with wire thickness up to 35 microns was developed. Methods to handle and mount these arrays were developed. Fabrication of wire arrays of 20mm diameter was demonstrated, and the path to 40mm array fabrication is clear. With some final investment to show array mounting into Z hardware, the entire process to produce a microfabricated wire array will have been demonstrated.
Date: October 1, 2008
Creator: Spahn, Olga Blum; Rowen, Adam M.; Cich, Michael Joseph; Peake, Gregory Merwin; Arrington, Christian L.; Nash, Thomas J. et al.
Object Type: Report
System: The UNT Digital Library
Modified MTS MRB500 Catalyst Performance Test (open access)

Modified MTS MRB500 Catalyst Performance Test

An experiment was conducted to determine if the oxygen supply in a CuO catalyst considered for use in the TMIST-2 irradiation test would be sufficient to convert all the hydrogen isotopes coming from the irradiation test to water. A mixture of 2% H2 in Ar was supplied to a modified MRB 500 stack m onitor from Mound Techology Solutions, Miamisburg, OH. It was found that the catalyst could convert 3.75E-03 moles of H2 before losing its effectiveness. Conversion was found to begin at a catalyst temperature of about 220 deg C and to be fully effective at about 300 deg C.
Date: October 1, 2008
Creator: Longhurst, Glen R. & Pawelko, Robert J.
Object Type: Report
System: The UNT Digital Library
Probing mSUGRA with a Search for Chargino-Neutralino Production using Trileptons (open access)

Probing mSUGRA with a Search for Chargino-Neutralino Production using Trileptons

This thesis describes the CDF II 2 fb{sup -1} search for supersymmetric chargino-neutralino production in {radical}s = 1.96TeV p{bar p} collisions using the 'golden' channel with three leptons and missing transverse energy in the final state and the application of the results to obtain a limit on the parameter space of the supersymmetric model mSUGRA. Electrons and muons are reconstructed directly; isolated tracks are used as a proxy for {tau} leptons. Several analysis channels with different signal purity are defined and evaluated independently. Based on 7 observed and 6.4 expected background events this analysis was able set the first direct limits on chargino-neutralino production in mSUGRA since LEP. Based on mSUGRA phenomenology the sensitivity of this analysis is investigated; the mSUGRA parameter space is split into different phenomenology classes. Experimental results from previous searches in this channel by CDF and D0 have been presented for specific parameter values of a given model. A more model-independent approach is proposed and, by splitting the results of this analysis into channels based on {tau} content, the results of the analysis are generalized.
Date: October 1, 2008
Creator: Glatzer, Julian
Object Type: Report
System: The UNT Digital Library
Theory and praxis pf map analsys in CHEF part 1: Linear normal form (open access)

Theory and praxis pf map analsys in CHEF part 1: Linear normal form

This memo begins a series which, put together, could comprise the 'CHEF Documentation Project' if there were such a thing. The first--and perhaps only--three will telegraphically describe theory, algorithms, implementation and usage of the normal form map analysis procedures encoded in CHEF's collection of libraries. [1] This one will begin the sequence by explaining the linear manipulations that connect the Jacobian matrix of a symplectic mapping to its normal form. It is a 'Reader's Digest' version of material I wrote in Intermediate Classical Dynamics (ICD) [2] and randomly scattered across technical memos, seminar viewgraphs, and lecture notes for the past quarter century. Much of its content is old, well known, and in some places borders on the trivial.1 Nevertheless, completeness requires their inclusion. The primary objective is the 'fundamental theorem' on normalization written on page 8. I plan to describe the nonlinear procedures in a subsequent memo and devote a third to laying out algorithms and lines of code, connecting them with equations written in the first two. Originally this was to be done in one short paper, but I jettisoned that approach after its first section exceeded a dozen pages. The organization of this document is as follows. A …
Date: October 1, 2008
Creator: Michelotti, Leo
Object Type: Report
System: The UNT Digital Library
NuMI proton beam diagnostics and control: achieving 2 megawatt capability (open access)

NuMI proton beam diagnostics and control: achieving 2 megawatt capability

The NuMI proton beam at Fermilab currently delivers 120 GeV protons to the neutrino production target with design beam power capability to 400 kW. Upgrade capability to 700 kW is being prepared, with planning toward delivering 2.3 MW beam provided by the Project X accelerator upgrade plan. We report on the system of beam diagnostics and control used in operation of the NuMI beam. Also considered are the steps to provide a robust system for transport and targeting beam of 2 MW and beyond.
Date: October 1, 2008
Creator: Childress, S.
Object Type: Article
System: The UNT Digital Library
Characterization of the self magnetic pinch diode at high voltages for flash radiography. (open access)

Characterization of the self magnetic pinch diode at high voltages for flash radiography.

The Sandia Laboratories Advanced Radiographic Technologies Department, in collaboration with the United Kingdom Atomic Weapons Establishment, has been conducting research into the development of the Self-Magnetic-Pinched diode as an x-ray source suitable for flash radiographic experiments. We have demonstrated that this source is capable of meeting and exceeding the initial requirements of 250 rads (measured at one meter) with a 2.75 mm source spot-size. Recent experiments conducted on the RITS-6 accelerator have demonstrated the ability of this diode to meet intermediate requirements with a sub 3 mm source spot size and a dose in excess of 400 rads at one meter.
Date: October 1, 2008
Creator: Cordova, Steve Ray; Portillo, Salvador; Oliver, Bryan Velten; Threadgold, James R. (Atomic Weapons Establishment Aldermaston, Reading Berkshire, U.K.); Crotch, Ian (Atomic Weapons Establishment Aldermaston, Reading Berkshire, U.K.) & Ziska, Derek Raymond
Object Type: Report
System: The UNT Digital Library
2007 Site Environmental Report (open access)

2007 Site Environmental Report

Brookhaven National Laboratory (BNL) prepares an annual Site Environmental Report (SER) in accordance with DOE Order 231.1A, Environment, Safety and Health Reporting of the U.S. Department of Energy. The report is written to inform the public, regulators, employees, and other stakeholders of the Laboratory's environmental performance during the calendar year in review. Volume I of the SER summarizes environmental data; environmental management performance; compliance with applicable DOE, federal, state, and local regulations; and performance in restoration and surveillance monitoring programs. BNL has prepared annual SERs since 1971 and has documented nearly all of its environmental history since the Laboratory's inception in 1947. Volume II of the SER, the Groundwater Status Report, also is prepared annually to report on the status of and evaluate the performance of groundwater treatment systems at the Laboratory. Volume II includes detailed technical summaries of groundwater data and its interpretation, and is intended for internal BNL users, regulators, and other technically oriented stakeholders. A brief summary of the information contained in Volume II is included in this volume in Chapter 7, Groundwater Protection. Both reports are available in print and as downloadable files on the BNL web page at http://www.bnl.gov/ewms/ser/. An electronic version on compact disc …
Date: October 1, 2008
Creator: Ratel,K.
Object Type: Report
System: The UNT Digital Library
Addendum to the Closure Report for Corrective Action Unit 427: Area 3 Septic Waste Systems 2, 6, Tonopah Test Range, Nevada, Revision 0 (open access)

Addendum to the Closure Report for Corrective Action Unit 427: Area 3 Septic Waste Systems 2, 6, Tonopah Test Range, Nevada, Revision 0

This document constitutes an addendum to the April 1999, Closure Report for Corrective Action Unit 427: Area 3 Septic Waste Systems 2, 6, Tonopah Test Range, Nevada as described in the document Recommendations and Justifications for Modifications for Use Restrictions Established under the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office Federal Facility Agreement and Consent Order (UR Modification document) dated February 2008. The UR Modification document was approved by NDEP on February 26, 2008. The approval of the UR Modification document constituted approval of each of the recommended UR modifications. In conformance with the UR Modification document, this addendum consists of: • This cover page that refers the reader to the UR Modification document for additional information • The cover and signature pages of the UR Modification document • The NDEP approval letter • The corresponding section of the UR Modification document This addendum provides the documentation justifying the cancellation of the URs for: • CAS 03-05-002-SW02, Septic Waste System • CAS 03-05-002-SW06, Septic Waste System These URs were established as part of Federal Facility Agreement and Consent Order (FFACO) corrective actions and were based on the presence of contaminants at concentrations greater than the action …
Date: October 1, 2008
Creator: Kidman, Lynn
Object Type: Report
System: The UNT Digital Library
Insecticide Exposures on Commercial Aircraft: A Literature Review and Screening Level Assessment (open access)

Insecticide Exposures on Commercial Aircraft: A Literature Review and Screening Level Assessment

The objective of this project was to provide initial estimates of the relationship between insecticide use on passenger aircraft and exposure levels present in the cabin environment. The work was initially divided into three tasks including 1) a review of insecticide application practices in commercial aircraft, 2) exploratory measurements of insecticide concentrations in treated aircraft and 3) screening level exposure modeling. Task 1 gathered information that is needed to assess the time-concentration history of insecticides in the airline cabin. The literature review focused on application practices, information about the cabin environment and existing measurements of exposure concentrations following treatment. Information from the airlines was not available for estimating insecticide application rates in the U.S. domestic fleet or for understanding how frequently equipment rotate into domestic routes following insecticide treatment. However, the World Health Organization (WHO) recommends several methods for treating aircraft with insecticide. Although there is evidence that these WHO guidelines may not always be followed, and that practices vary by airline, destination, and/or applicator company, the guidelines in combination with information related to other indoor environments provides a plausible basis for estimating insecticide loading rates on aircraft. The review also found that while measurements of exposure concentrations following simulated …
Date: October 1, 2008
Creator: Maddalena, Randy I. & McKone, Thomas E.
Object Type: Report
System: The UNT Digital Library
Electromagnetic and hadron calorimeters in the MIPP experiment (open access)

Electromagnetic and hadron calorimeters in the MIPP experiment

The purpose of the MIPP experiment is to study the inclusive production of photons, pions, kaons, and nucleons in {pi}, K, and p interactions on various targets using beams from the Main Injector at Fermilab. The function of the calorimeters is to measure the production of forward-going neutrons and photons. The electromagnetic calorimeter consists of 10 lead plates interspersed with proportional chambers. It was followed by the hadron calorimeter with 64 steel plates interspersed with scintillator. The data presented were collected with a variety of targets and beam momenta from 5 to 120 GeV/c. The energy calibration of both calorimeters with electrons, pions, kaons, and protons is discussed. The resolution for electrons was found to be 0.27/{radical}E, and for hadrons the resolution was 0.554/{radical}E with a constant term of 2.6%. The performance of the calorimeters was tested on a neutron sample.
Date: October 1, 2008
Creator: Nigmanov, T. S.; Gustafson, H. R.; Longo, M. J.; Park, H. K.; Rajaram, D.; Dukes, C. et al.
Object Type: Article
System: The UNT Digital Library
Experimental and Modeling Study of the Flammability of Fuel Tank Headspace Vapors from High Ethanol Content Fuels (open access)

Experimental and Modeling Study of the Flammability of Fuel Tank Headspace Vapors from High Ethanol Content Fuels

Study determined the flammability of fuel tank headspace vapors as a function of ambient temperature for seven E85 fuel blends, two types of gasoline, and denatured ethanol at a low tank fill level.
Date: October 1, 2008
Creator: Gardiner, D.; Bardon, M. & Pucher, G.
Object Type: Report
System: The UNT Digital Library
Zn-Site Determination in Protein Encapsulated ZnxFe3-xO4 Nanoparticles (open access)

Zn-Site Determination in Protein Encapsulated ZnxFe3-xO4 Nanoparticles

The X-ray absorption spectra of the Fe and Zn L-edges for 6.7 nm Fe{sub 3}O{sub 4} nanoparticles grown inside 12 nm ferritin protein cages with 10%, 15%, 20% and 33% zinc doping, shows that the Zn is substitutional as Zn{sup 2+} within the iron oxide host structure. A Neel-Arrhenius plot of the blocking temperature in the frequency dependent ac-susceptibility measurements show that the particles are non-interacting and that the anisotropy energy barrier is reduced with Zn loading. X-ray magnetic circular dichroism (XMCD) of the Fe displays a linear decrease with Zn-doping in sharp contrast to the initial increase present in the bulk system. The most plausible explanation for the moment decrease is that Zn substitutes preferentially into the tetrahedral A-site as a Zn{sup 2+} cation, generating a mixed spinel.
Date: October 1, 2008
Creator: Pool, V. L.; Klem, M. T.; Holroyd, J.; Harris, T.; Arenholz, E.; Young, M. et al.
Object Type: Article
System: The UNT Digital Library