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Measurement of Fast Voltage Transients in High-Performance Nb3Sn Magnets (open access)

Measurement of Fast Voltage Transients in High-Performance Nb3Sn Magnets

The Superconducting Magnet group at Lawrence Berkeley National Laboratory has been developing Nb{sub 3}Sn high-field accelerator magnet technology for the last fifteen years. In order to support the magnet R&D effort, we are developing a diagnostic system that can help identify the causes of performance limiting quenches by recording small flux-changes within the magnet prior to quench-onset. These analysis techniques were applied to the test results from recent Nb{sub 3}Sn magnets. This paper will examine various types of events and their distinguishing characteristics. The present measurement techniques are discussed along with the design of a new data acquisition system that will substantially improve the quality of the recorded signals.
Date: June 1, 2008
Creator: Lietzke, A. F.; Sabbi, G. L.; Ferracin, P.; Caspi, S.; Zimmerman, S.; Joseph, J. et al.
System: The UNT Digital Library
Initial Operation of the High Temperature Electrolysis Integrated Laboratory Scale Experiment at INL (open access)

Initial Operation of the High Temperature Electrolysis Integrated Laboratory Scale Experiment at INL

An integrated laboratory scale, 15 kW high-temperature electrolysis facility has been developed at the Idaho National Laboratory under the U.S. Department of Energy Nuclear Hydrogen Initiative. Initial operation of this facility resulted in over 400 hours of operation with an average hydrogen production rate of approximately 0.9 Nm3/hr. The integrated laboratory scale facility is designed to address larger-scale issues such as thermal management (feed-stock heating, high-temperature gas handling), multiple-stack hot-zone design, multiple-stack electrical configurations, and other “integral” issues. This paper documents the initial operation of the ILS, with experimental details about heat-up, initial stack performance, as well as long-term operation and stack degradation.
Date: June 1, 2008
Creator: Stoots, C. M.; O'Brien, J. E.; Condie, K. G.; Herring, J. S. & Hartvigsen, J. J.
System: The UNT Digital Library
Magnet R&D for the US LHC Accelerator Research Program (LARP) (open access)

Magnet R&D for the US LHC Accelerator Research Program (LARP)

In 2004, the US DOE established the LHC Accelerator Research Program (LARP) with the goal of developing a technology base for future upgrades of the LHC. The focus of the magnet program, which is a collaboration of three US laboratories, BNL, FNAL and LBNL, is on development of high gradient quadrupoles using Nb{sub 3}Sn superconductor. Other program components address issues regarding magnet design, radiation-hard materials, long magnet scale-up, quench protection, fabrication techniques and conductor and cable R&D. This paper presents an overall view of the program with emphasis on the current quadrupole project and outlines the long-term goals of the program.
Date: June 1, 2006
Creator: Gourlay, S. A.; Ambrosio, G.; Andreev, N.; Anerella, M.; Barzi, E.; Bossert, R. et al.
System: The UNT Digital Library
Electron cooling rates characterization at Fermilab's Recycler (open access)

Electron cooling rates characterization at Fermilab's Recycler

A 0.1 A, 4.3 MeV DC electron beam is routinely used to cool 8 GeV antiprotons in Fermilab's Recycler storage ring [1]. The primary function of the electron cooler is to increase the longitudinal phase-space density of the antiprotons for storing and preparing high-density bunches for injection into the Tevatron. The longitudinal cooling rate is found to significantly depend on the transverse emittance of the antiproton beam. The paper presents the measured rates and compares them with calculations based on drag force data.
Date: June 1, 2007
Creator: Prost, Lionel R. & Shemyakin, A.
System: The UNT Digital Library
Stochastic Transport Modeling of Resonant Magnetic Perturbations in DIII-D (open access)

Stochastic Transport Modeling of Resonant Magnetic Perturbations in DIII-D

Three-dimensional two-fluid simulations of heat transport due to resonant magnetic perturbations of tokamaks have been computed by coupling the TRIP3D field line tracing code to the E3D edge transport code. The predicted electron temperature contours follow the new separatrix represented by the perturbed invariant manifold structure of the X-point in qualitative agreement with X-point TV observations. However, preliminary modeling predicts that the resulting stochastic heat transport is greater than that measured in low-collisionality ELM suppression experiments in DIII-D H-mode plasmas. While improved determination of transport coefficients is definitely required, possible explanations include plasma screening of resonant perturbations, invalid treatment of the edge as a fluid, or insufficient understanding of stochastic heat transport.
Date: June 1, 2006
Creator: Joseph, I.; Moyer, R. A.; Evans, T. E.; Schaffer, M. J.; Runov, A. M.; Schneider, R. et al.
System: The UNT Digital Library
Investigation of possible csr induced energy spread effects with the A0 photoinjector bunch compressor (open access)

Investigation of possible csr induced energy spread effects with the A0 photoinjector bunch compressor

The bunch compressor of the A0 Photoinjector at Fermilab was removed this past spring to install a transverse to longitudinal emittance exchange experiment. Prior to its removal questions arose about the possibility of observing the effects of Coherent Synchrotron Radiation on the compressed beam. The energy spread of the beam with and without compression was measured to observe any changes. Various beam charges were used to look for square law effects associated with CSR. No direct observation of CSR in the compressor was attempted because the design of the vacuum chamber did not allow it. In this paper we report the results of these experiments and comparison with simulations using ASTRA and CSRTrack. The results are also compared with analytical approximations.
Date: June 1, 2008
Creator: Edwards, H.; Kazakevich, G.; Thurman-Keup, R. M. & Ruan, J.
System: The UNT Digital Library
Using Contingent Valuation to Explore Willingness to Pay forRenewable Energy: A Comparison of Collective and Voluntary PaymentVehicles (open access)
Relationships between walking and percentiles of adiposity inolder and younger men (open access)

Relationships between walking and percentiles of adiposity inolder and younger men

To assess the relationship of weekly walking distance to percentiles of adiposity in elders (age {ge} 75 years), seniors (55 {le} age <75 years), middle-age men (35 {le} age <55 years), and younger men (18 {le} age <35 years old). Cross-sectional analyses of baseline questionnaires from 7,082 male participants of the National Walkers Health Study. The walkers BMIs were inversely and significantly associated with walking distance (kg/m{sup 2} per km/wk) in elders (slope {+-} SE: -0.032 {+-} 0.008), seniors (-0.045 {+-} 0.005), and middle-aged men (-0.037 {+-} 0.007), as were their waist circumferences (-0.091 {+-} 0.025, -0.045 {+-} 0.005, and -0.091 {+-} 0.015 cm per km/wk, respectively), and these slopes remained significant when adjusted statistically for reported weekly servings of meat, fish, fruit, and alcohol. The declines in BMI associated with walking distance were greater at the higher than lower percentiles of the BMI distribution. Specifically, compared to the decline at the 10th BMI percentile, the decline in BMI at the 90th percentile was 5.1-fold greater in elders, 5.9-fold greater in seniors, and 6.7-fold greater in middle-age men. The declines in waist circumference associated with walking distance were also greater among men with broader waistlines. Exercise-induced weight loss (or self-selection) …
Date: June 1, 2005
Creator: Williams, Paul T.
System: The UNT Digital Library
Fabrication of a Short-Period Nb3Sn Superconducting Undulator (open access)

Fabrication of a Short-Period Nb3Sn Superconducting Undulator

Lawrence Berkeley National Laboratory develops high-field Nb{sub 3}Sn magnets for HEP applications. In the past few years, this experience has been extended to the design and fabrication of undulator magnets. Some undulator applications require devices that can operate in the presence of a heat load from a beam. The use of Nb{sub 3}Sn permits operation of a device at both a marginally higher temperature (5-8K) and a higher J{sub c}, compared to NbTi devices, without requiring a larger magnetic gap. A half-undulator device consisting of 6 periods (12 coil packs) of 14.5 mm period was designed, wound, reacted, potted and tested. It reached the short sample current limit of 717A in 4 quenches. The non-Cu Jc of the strand was over 7,600 A/mm{sup 2} and the Cu current density at quench was over 8,000 A/mm{sup 2}. Magnetic field models show that if a complete device was fabricated with the same parameters one could obtain beam fields of 1.1 T and 1.6 T for pole gaps of 8 mm and 6 mm, respectively.
Date: June 1, 2007
Creator: Dietderich, Daniel; Dietderich, Daniel; Godeke, Arno; Prestemon, Soren; Pipersky, Paul T.; Liggins, Nate L. et al.
System: The UNT Digital Library
Supersymmetry Searches at the Tevatron (open access)

Supersymmetry Searches at the Tevatron

None
Date: June 1, 2008
Creator: Strologas, John
System: The UNT Digital Library
Measurement of Flow Phenomena in a VHTR Lower Plenum Model (open access)

Measurement of Flow Phenomena in a VHTR Lower Plenum Model

Mean velocity and turbulence data that measure turbulent flow phenomena in an approximately 1:7 scale model of a region of the lower plenum of a typical prismatic gas-cooled reactor are presented as a follow-up to summaries presented at the 2006 Annual Meeting and the 2006 Winter Meeting. The experiments were designed to develop benchmark databases to support the first Standard Problem endorsed by the Generation IV International Forum to validate the heat transfer and fluid flow software that will be used to study the behavior of the VHTR system.
Date: June 1, 2007
Creator: Jr., Hugh M. McIlroy; McEligot, Donald M. & Pink, Robert J.
System: The UNT Digital Library
Decays of B_s Mesons and b Baryons: A Review of Recent First Observations and Branching Fractions (open access)

Decays of B_s Mesons and b Baryons: A Review of Recent First Observations and Branching Fractions

Recent rate measurements of B{sub s}{sup 0} mesons and {Lambda}{sub b}{sup 0} baryons produced in {radical}s = 1.96 TeV proton-antiproton and {Upsilon}(5S) electron-positron collisions are reviewed, including the first observations of six new decay modes: B{sub s}{sup 0} {yields} D{sub s}{sup +} K{sup -} (CDF), B{sub s}{sup 0} {yields} D{sub s}{sup -} D{sub s}{sup +} (CDF), B{sub s}{sup 0} {yields} D{sub s1}{sup -}(2536){mu}{sup +} {nu}{sub {mu}} X (DZero), B{sub s}{sup 0} {yields} {phi}{gamma} (Belle)< {Lambda}{sub b}{sup 0} {yields} p{pi}{sup -} (CDF), and {Lambda}{sub b}{sup 0} {yields} pK{sup -} (CDF). Also examined are branching-fraction measurements or limits for the B{sub s}{sup 0} {yields} D{sub s}{sup (*)} D{sub s}{sup (*)} modes (Belle, CDF, and DZero), the B{sub s}{sup 0} {yields} {gamma}{gamma} radiative penguin decay (Belle), and three two-body charmless B{sub s}{sup 0} meson decay channels (CDF). Implications for the phenomenology of electroweak and QCD physics, as well as searches for physics beyond the Standard Model, are identified where applicable.
Date: June 1, 2008
Creator: Warburton, Andreas
System: The UNT Digital Library
Optimization of the Helical Orbits in the Tevatron (open access)

Optimization of the Helical Orbits in the Tevatron

To avoid multiple head-on collisions the proton and antiproton beams in the Tevatron move along separate helical orbits created by 7 horizontal and 8 vertical electrostatic separators. Still the residual long-range beam-beam interactions can adversely affect particle motion at all stages from injection to collision. With increased intensity of the beams it became necessary to modify the orbits in order to mitigate the beam-beam effect on both antiprotons and protons. This report summarizes the work done on optimization of the Tevatron helical orbits, outlines the applied criteria and presents the achieved results.
Date: June 1, 2007
Creator: Alexahin, Y.
System: The UNT Digital Library
Demonstration of Femtosecond-Phase Stabilization in 2 km OpticalFiber (open access)

Demonstration of Femtosecond-Phase Stabilization in 2 km OpticalFiber

Long-term phase drifts of less than a femtosecond per hour have been demonstrated in a 2 km length of single-mode optical fiber, stabilized interferometrically at 1530 nm. Recent improvements include a wide-band phase detector that reduces the possibility of fringe jumping due to fast external perturbations of the fiber and locking of the master CW laser wavelength to an atomic absorption line. Mode-locked lasers may be synchronized using two wavelengths of the comb, multiplexed over one fiber, each wavelength individually interferometrically stabilized.
Date: June 1, 2007
Creator: Staples, J. W.; Wilcox, R. & Byrd, J. M.
System: The UNT Digital Library
Transatlantic transport of Fermilab 3.9 GHz cryomodule for TTF/FLASH to DESY (open access)

Transatlantic transport of Fermilab 3.9 GHz cryomodule for TTF/FLASH to DESY

In an exchange of technology agreement, Fermilab built and will deliver a 3.9 GHz (3rd harmonic) cryomodule to DESY to be installed in the TTF/FLASH beamline. This cryomodule delivery will involve a combination of flatbed air ride truck and commercial aircraft transport to Hamburg Germany. A description of the isolation and damping systems that maintain alignment during transport and protect fragile components is provided. Initially, transport and corresponding alignment stability studies were performed in order to assess the risk associated with transatlantic travel of a fully assembled cryomodule. Shock loads were applied to the cryomodule by using a coldmass mockup to prevent subjecting actual critical components (such as the cavities and input couplers) to excessive forces. Accumulative and peak shock loads were applied through over-the-road testing and using a pendulum hammer apparatus, respectively. Finite Element Analysis (FEA) studies were implemented to define location of instrumentation for transport studies and provide modal frequencies and shapes. Shock and vibration measurement results of transport studies and stabilization techniques are discussed.
Date: June 1, 2008
Creator: McGee, M. W.; Vocean, V.; Grimm, C. & Schappert, W.
System: The UNT Digital Library
NIF: A Path to Fusion Energy (open access)

NIF: A Path to Fusion Energy

Fusion energy has long been considered a promising, clean, nearly inexhaustible source of energy. Power production by fusion micro-explosions of inertial confinement fusion (ICF) targets has been a long-term research goal since the invention of the first laser in 1960. The National Ignition Facility (NIF) is poised to take the next important step in the journey by beginning experiments researching ICF ignition. Ignition on NIF will be the culmination of over thirty years of ICF research on high-powered laser systems such as the Nova laser at Lawrence Livermore National Laboratory (LLNL) and the OMEGA laser at the University of Rochester, as well as smaller systems around the world. NIF is a 192-beam Nd-glass laser facility at LLNL that is more than 90% complete. The first cluster of 48 beams is operational in the laser bay, the second cluster is now being commissioned, and the beam path to the target chamber is being installed. The Project will be completed in 2009, and ignition experiments will start in 2010. When completed, NIF will produce up to 1.8 MJ of 0.35-{micro}m light in highly shaped pulses required for ignition. It will have beam stability and control to higher precision than any other laser …
Date: June 1, 2007
Creator: Moses, Edward
System: The UNT Digital Library
Modeling the Benefits of Storage Technologies to Wind Power (open access)

Modeling the Benefits of Storage Technologies to Wind Power

Rapid expansion of wind power in the electricity sector is raising questions about how wind resource variability might affect the capacity value of wind farms at high levels of penetration. Electricity storage, with the capability to shift wind energy from periods of low demand to peak times and to smooth fluctuations in output, may have a role in bolstering the value of wind power at levels of penetration envisioned by a new Department of Energy report ('20% Wind by 2030, Increasing Wind Energy's Contribution to U.S. Electricity Supply'). This paper quantifies the value storage can add to wind. The analysis was done employing the Regional Energy Deployment System (ReEDS) model, formerly known as the Wind Deployment System (WinDS) model. ReEDS was used to estimate the cost and development path associated with 20% penetration of wind in the report. ReEDS differs from the WinDS model primarily in that the model has been modified to include the capability to build and use three storage technologies: pumped-hydroelectric storage (PHS), compressed-air energy storage (CAES), and batteries. To assess the value of these storage technologies, two pairs of scenarios were run: business-as-usual, with and without storage; 20% wind energy by 2030, with and without storage. …
Date: June 1, 2008
Creator: Sullivan, P.; Short, W. & Blair, N.
System: The UNT Digital Library
An Overview of Current and Past W-UO[2] CERMET Fuel Fabrication Technology (open access)

An Overview of Current and Past W-UO[2] CERMET Fuel Fabrication Technology

Studies dating back to the late 1940s performed by a number of different organizations and laboratories have established the major advantages of Nuclear Thermal Propulsion (NTP) systems, particularly for manned missions. A number of NTP projects have been initiated since this time; none have had any sustained fuel development work that appreciably contributed to fuel fabrication or performance data from this era. As interest in these missions returns and previous space nuclear power researchers begin to retire, fuel fabrication technologies must be revisited, so that established technologies can be transferred to young researchers seamlessly and updated, more advanced processes can be employed to develop successful NTP fuels. CERMET fuels, specifically W-UO2, are of particular interest to the next generation NTP plans since these fuels have shown significant advantages over other fuel types, such as relatively high burnup, no significant failures under severe transient conditions, capability of accommodating a large fission product inventory during irradiation and compatibility with flowing hot hydrogen. Examples of previous fabrication routes involved with CERMET fuels include hot isostatic pressing (HIPing) and press and sinter, whereas newer technologies, such as spark plasma sintering, combustion synthesis and microsphere fabrication might be well suited to produce high quality, effective …
Date: June 1, 2007
Creator: Burkes, Douglas E.; Wachs, Daniel M.; Werner, James E. & Howe, Steven D.
System: The UNT Digital Library
Experimental Demonstration of Beam-Beam Compensation by Tevatron Electron Lenses and Prospects for the LHC (open access)

Experimental Demonstration of Beam-Beam Compensation by Tevatron Electron Lenses and Prospects for the LHC

Contains the observations of the beam-beam phenomena in the Tevatron and results of relevant beam studies.
Date: June 1, 2007
Creator: Shiltsev, V.; Alexahin, Y.; Kamerdzhiev, V.; Kuznetsov, G.; Zhang, X.L. & Bishofberger, K.
System: The UNT Digital Library
Measurement of b-jet Shapes in Inclusive Jet Production in p anti-p Collisions at s**(1/2) = 1.96-TeV (open access)

Measurement of b-jet Shapes in Inclusive Jet Production in p anti-p Collisions at s**(1/2) = 1.96-TeV

We present a measurement of the shapes of b-jets using 300 pb{sup -1} of data obtained with the upgraded Collider Detector at Fermilab (CDF II) in p{bar p} collisions at center of mass energy {radical}s = 1.96 TeV. This measurement covers a wide transverse momentum range, from 52 to 300 GeV/c. Samples of heavy-flavor enhanced jets together with inclusive jets are used to extract the average shapes of b-jets. The b-jets are expected to be broader than inclusive jets. Moreover, b-jets containing a single b-quark are expected to be narrower than those containing a b{bar b} pair from gluon splitting. The measured b-jet shapes are found to be significantly broader than expected from the pythia and HERWIG Monte Carlo simulations. This effect may arise from an underestimation of the fraction of b-jets originating from gluon splitting in these simulations.
Date: June 1, 2008
Creator: Aaltonen, T.
System: The UNT Digital Library
Wireless Indoor Location Estimation Based on Neural Network RSS Signature Recognition (LENSR) (open access)

Wireless Indoor Location Estimation Based on Neural Network RSS Signature Recognition (LENSR)

Location Based Services (LBS), context aware applications, and people and object tracking depend on the ability to locate mobile devices, also known as localization, in the wireless landscape. Localization enables a diverse set of applications that include, but are not limited to, vehicle guidance in an industrial environment, security monitoring, self-guided tours, personalized communications services, resource tracking, mobile commerce services, guiding emergency workers during fire emergencies, habitat monitoring, environmental surveillance, and receiving alerts. This paper presents a new neural network approach (LENSR) based on a competitive topological Counter Propagation Network (CPN) with k-nearest neighborhood vector mapping, for indoor location estimation based on received signal strength. The advantage of this approach is both speed and accuracy. The tested accuracy of the algorithm was 90.6% within 1 meter and 96.4% within 1.5 meters. Several approaches for location estimation using WLAN technology were reviewed for comparison of results.
Date: June 1, 2008
Creator: Derr, Kurt & Manic, Milos
System: The UNT Digital Library
Recent Lifetime and Mixing Measurements at the Tevatron (open access)

Recent Lifetime and Mixing Measurements at the Tevatron

None
Date: June 1, 2008
Creator: Liu, Chunlei & U., /Pittsburgh
System: The UNT Digital Library
Development Of An Agroforestry Sequestration Project In KhammamDistrict Of India (open access)

Development Of An Agroforestry Sequestration Project In KhammamDistrict Of India

Large potential for agroforestry as a mitigation option hasgiven rise to scientific and policy questions. This paper addressesmethodological issues in estimating carbon sequestration potential,baseline determination, additionality and leakage in Khammam district,Andhra Pradesh, southern part of India. Technical potential forafforestation was determined considering the various landuse options. Forestimating the technical potential, culturable wastelands, fallow andmarginal croplands were considered for Eucalyptus clonal plantations.Field studies for aboveground and below ground biomass, woody litter andsoil organic carbon for baseline and project scenario were conducted toestimate the carbon sequestration potential. The baseline carbon stockwas estimated to be 45.33 tC/ha. The additional carbon sequestrationpotential under the project scenario for 30 years is estimated to be12.82 tC/ha/year inclusive of harvest regimes and carbon emissions due tobiomass burning and fertilizer application. The project scenario thoughhas a higher benefit cost ratio compared to baseline scenario, initialinvestment cost is high. Investment barrier exists for adoptingagroforestry in thedistrict.
Date: June 1, 2007
Creator: Sudha, P.; Ramprasad, V.; Nagendra, M.D.V.; Kulkarni, H.D. & Ravindranath, N.H.
System: The UNT Digital Library
Single-Phase Self-Oscillating Jets for Enhanced Heat Transfer: Preprint (open access)

Single-Phase Self-Oscillating Jets for Enhanced Heat Transfer: Preprint

Self-oscillating jets have potential to cool insulated gate bipolar transistors in vehicle power electronics modules.
Date: June 1, 2008
Creator: Narumanchi, S.; Kelly, K.; Mihalic, M.; Gopalan, S.; Hester, R. & Vlahinos, A.
System: The UNT Digital Library