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Gearbox Reliability Collaborative: Test and Model Investigation of Sun Orbit and Planet Load Share in a Wind Turbine Gearbox; Preprint (open access)

Gearbox Reliability Collaborative: Test and Model Investigation of Sun Orbit and Planet Load Share in a Wind Turbine Gearbox; Preprint

This paper analyzes experimental measurement of the sun gear orbit in dynamometer testing and describes its relation to the other measured responses of the planetary stage. The relation of the sun orbit to component runout, component flexibility, gear coupling alignment, planet load share, and planet position error will be investigated. Equations describing the orbit of the sun gear in the test cases are derived. Rigid and flexible multibody models of the full gearbox are investigated and compared to sun and planet measurements. This paper shows that the sun gear's path may be influenced by gear coupling responses and gearbox structural flexibilities.
Date: April 1, 2012
Creator: LaCava, W.; Keller, J. & McNiff, B.
System: The UNT Digital Library
Outdoor PV Module Degradation of Current-Voltage Parameters: Preprint (open access)

Outdoor PV Module Degradation of Current-Voltage Parameters: Preprint

Photovoltaic (PV) module degradation rate analysis quantifies the loss of PV power output over time and is useful for estimating the impact of degradation on the cost of energy. An understanding of the degradation of all current-voltage (I-V) parameters helps to determine the cause of the degradation and also gives useful information for the design of the system. This study reports on data collected from 12 distinct mono- and poly-crystalline modules deployed at the National Renewable Energy Laboratory (NREL) in Golden, Colorado. Most modules investigated showed < 0.5%/year decrease in maximum power due to short-circuit current decline.
Date: April 1, 2012
Creator: Smith, R. M.; Jordan, D. C. & Kurtz, S. R.
System: The UNT Digital Library
Requirements for Computer Based-Procedures for Nuclear Power Plant Field Operators Results from a Qualitative Study (open access)

Requirements for Computer Based-Procedures for Nuclear Power Plant Field Operators Results from a Qualitative Study

Although computer-based procedures (CBPs) have been investigated as a way to enhance operator performance on procedural tasks in the nuclear industry for almost thirty years, they are not currently widely deployed at United States utilities. One of the barriers to the wide scale deployment of CBPs is the lack of operational experience with CBPs that could serve as a sound basis for justifying the use of CBPs for nuclear utilities. Utilities are hesitant to adopt CBPs because of concern over potential costs of implementation, and concern over regulatory approval. Regulators require a sound technical basis for the use of any procedure at the utilities; without operating experience to support the use CBPs, it is difficult to establish such a technical basis. In an effort to begin the process of developing a technical basis for CBPs, researchers at Idaho National Laboratory are partnering with industry to explore CBPs with the objective of defining requirements for CBPs and developing an industry-wide vision and path forward for the use of CBPs. This paper describes the results from a qualitative study aimed at defining requirements for CBPs to be used by field operators and maintenance technicians.
Date: May 1, 2012
Creator: Blanc, Katya Le & Oxstrand, Johanna
System: The UNT Digital Library
DEVELOPMENT AND ASSESSMENT OF COATINGS FOR FUTURE POWER GENERATION TURBINES (open access)

DEVELOPMENT AND ASSESSMENT OF COATINGS FOR FUTURE POWER GENERATION TURBINES

The NETL-Regional University Alliance (RUA) continues to advance technology development critical to turbine manufacturer efforts for achieving DOE Fossil Energy (FE's) Advanced Turbine Program Goals. In conjunction with NETL, Coatings for Industry (CFI), the University of Pittsburgh, NASA GRC, and Corrosion Control Inc., efforts have been focused on development of composite thermal barrier coating (TBC) architectures that consist of an extreme temperature coating, a commercially applied 7-8 YSZ TBC, a reduced cost bond coat, and a diffusion barrier coating that are applied to nickel-based superalloys or single crystal airfoil substrate materials for use at temperatures >1450 C (> 2640 F). Additionally, construction of a unique, high temperature ({approx}1100 C; {approx}2010 F), bench-scale, micro-indentation, nondestructive (NDE) test facility at West Virginia University (WVU) was completed to experimentally address in-situ changes in TBC stiffness during extended cyclic oxidation exposure of coated single crystal coupons in air or steam containing environments. The efforts and technical accomplishments in these areas are presented in the following sections of this paper.
Date: January 1, 2012
Creator: Alvin, Maryanne; Klotz, K.; McMordie, B.; Gleeson, B.; Zhu, D.; Warnes, B. et al.
System: The UNT Digital Library
Design and Simulation of IOTA - a Novel Concept of Integrable Optics Test Accelerator (open access)

Design and Simulation of IOTA - a Novel Concept of Integrable Optics Test Accelerator

The use of nonlinear lattices with large betatron tune spreads can increase instability and space charge thresholds due to improved Landau damping. Unfortunately, the majority of nonlinear accelerator lattices turn out to be nonintegrable, producing chaotic motion and a complex network of stable and unstable resonances. Recent advances in finding the integrable nonlinear accelerator lattices have led to a proposal to construct at Fermilab a test accelerator with strong nonlinear focusing which avoids resonances and chaotic particle motion. This presentation will outline the main challenges, theoretical design solutions and construction status of the Integrable Optics Test Accelerator (IOTA) underway at Fermilab.
Date: May 1, 2012
Creator: Nagaitsev, S.; Valishev, A.; /Fermilab; Danilov, V.V.; Ridge, /Oak; Shatilov, D.N. et al.
System: The UNT Digital Library
Microworlds, Simulators, and Simulation: Framework for a Benchmark of Human Reliability Data Sources (open access)

Microworlds, Simulators, and Simulation: Framework for a Benchmark of Human Reliability Data Sources

In this paper, we propose a method to improve the data basis of human reliability analysis (HRA) by extending the data sources used to inform HRA methods. Currently, most HRA methods are based on limited empirical data, and efforts to enhance the empirical basis behind HRA methods have not yet yielded significant new data. Part of the reason behind this shortage of quality data is attributable to the data sources used. Data have been derived from unrelated industries, from infrequent risk-significant events, or from costly control room simulator studies. We propose a benchmark of four data sources: a simplified microworld simulator using unskilled student operators, a full-scope control room simulator using skilled student operators, a full-scope control room simulator using licensed commercial operators, and a human performance modeling and simulation system using virtual operators. The goal of this research is to compare findings across the data sources to determine to what extent data may be used and generalized from cost effective sources.
Date: June 1, 2012
Creator: Boring, Ronald; Kelly, Dana; Smidts, Carol; Mosleh, Ali & Dyre, Brian
System: The UNT Digital Library
Still Processing Tons of Data with QuickView (open access)

Still Processing Tons of Data with QuickView

This slide show is about data analysis for photonic Doppler velocimetry.
Date: October 21, 2012
Creator: Diaz, A. B.
System: The UNT Digital Library
Shielding of a hadron in a finite e-beam (open access)

Shielding of a hadron in a finite e-beam

The thorough study of coherent electron cooling, the modern cooling technique capable to deal with accelerators operating in the range of few TeVs, rises many interesting questions. One of them is a shielding dynamics of a hadron in an electron beam. Now this effect is computed analytically in the infinite beam approximation. Many effects are drastically different in finite and infinite plasmas. Here we propose a method to compute the dynamical shielding effect in a finite cylindrical plasma - the realistic model of an electron beam in accelerators.
Date: May 20, 2012
Creator: A., Elizarov; Litvinenko, V. & Wang, G.
System: The UNT Digital Library
Ionic Liquids: Radiation Chemistry, Solvation Dynamics and Reactivity Patterns (open access)

Ionic Liquids: Radiation Chemistry, Solvation Dynamics and Reactivity Patterns

N/A
Date: October 21, 2012
Creator: F., Wishart J.
System: The UNT Digital Library
Plasma-Accelerated Flyer-Plates for Equation of State Studies (open access)

Plasma-Accelerated Flyer-Plates for Equation of State Studies

None
Date: February 13, 2012
Creator: Fratanduono, D E; Smith, R F; Boehly, T R; Eggert, J H; Braun, D G & Collins, G W
System: The UNT Digital Library
Considerations for Possible Light Impact of Spent Nuclear Fuel for Safeguards Measurements (open access)

Considerations for Possible Light Impact of Spent Nuclear Fuel for Safeguards Measurements

This effort is designed to be a preliminary study to determine the appropriateness of lightly contacting SNF with zirconium-based cladding, in wet storage, for the purpose of taking safeguards measurements. Contact will likely consist of an initial impact followed by a light tensile load on the exterior surface of the SNF cladding. In the past, concerns have been raised that contacting SNF cladding could result in a loss of long-term mechanical integrity due to crack initiation, uncontrolled crack propagation, and a mechanical exfoliation of the protective oxide layer. The mechanical integrity concerns are addressed with an analytic model that evaluates the threshold impact limits for degraded, but undamaged SNF cladding. Aqueous corrosion concerns, associated with exfoliation of the protective oxide layer, are addressed with a qualitative argument, focusing on the possible corrosion mechanisms of zirconium-based cladding.
Date: September 1, 2012
Creator: Castle, Brian K. & Ellis, Kelly D.
System: The UNT Digital Library
Electroexcitation of nucleon resonances (open access)

Electroexcitation of nucleon resonances

We review recent progress in the investigation of the electroexcitation of nucleon resonances, both in experiment and in theory. The most accurate results have been obtained for the electroexcitation amplitudes of the four lowest excited states, which have been measured in a range of Q2 up to 8 and 4.5 GeV2 for the Delta(1232)P33, N(1535)S11 and N(1440)P11, N(1520)D13, respectively. These results have been confronted with calculations based on lattice QCD, large-Nc relations, perturbative QCD (pQCD), and QCD-inspired models. The amplitudes for the Delta(1232) indicate large pion-cloud contributions at low Q2 and don't show any sign of approaching the pQCD regime for Q2<7 GeV2. Measured for the first time, the electroexcitation amplitudes of the Roper resonance, N(1440)P11, provide strong evidence for this state as a predominantly radial excitation of a three-quark (3q) ground state, with additional non-3-quark contributions needed to describe the low Q2 behavior of the amplitudes. The longitudinal transition amplitude for the N(1535)S11 was determined and has become a challenge for quark models. Explanations may require large meson-cloud contributions or alternative representations of this state. The N(1520)D13 clearly shows the rapid changeover from helicity-3/2 dominance at the real photon point to helicity-1/2 dominance at Q2 > 0.5 GeV2, confirming …
Date: January 1, 2012
Creator: Inna Aznauryan, Volker D. Burkert
System: The UNT Digital Library
Effects of Changing Atmospheric Conditions on Wind Turbine Performance (Poster) (open access)

Effects of Changing Atmospheric Conditions on Wind Turbine Performance (Poster)

Multi-megawatt, utility-scale wind turbines operate in turbulent and dynamic winds that impact turbine performance in ways that are gradually becoming better understood. This poster presents a study made using a turbulent flow field simulator (TurbSim) and a Turbine aeroelastic simulator (FAST) of the response of a generic 1.5 MW wind turbine to changing inflow. The turbine power output is found to be most sensitive to wind speed and turbulence intensity, but the relationship depends on the wind speed with respect to the turbine's rated wind speed. Shear is found to be poorly correlated to power. A machine learning method called 'regression trees' is used to create a simple model of turbine performance that could be used as part of the wind resource assessment process. This study has used simple flow fields and should be extended to more complex flows, and validated with field observations.
Date: December 1, 2012
Creator: Clifton, A.
System: The UNT Digital Library
Universality of the Volume Bound in Slow-Roll Eternal Inflation (open access)

Universality of the Volume Bound in Slow-Roll Eternal Inflation

It has recently been shown that in single field slow-roll inflation the total volume cannot grow by a factor larger than e{sup S{sub dS}/2} without becoming infinite. The bound is saturated exactly at the phase transition to eternal inflation where the probability to produce infinite volume becomes non zero. We show that the bound holds sharply also in any space-time dimensions, when arbitrary higher-dimensional operators are included and in the multi-field inflationary case. The relation with the entropy of de Sitter and the universality of the bound strengthen the case for a deeper holographic interpretation. As a spin-off we provide the formalism to compute the probability distribution of the volume after inflation for generic multi-field models, which might help to address questions about the population of vacua of the landscape during slow-roll inflation.
Date: March 28, 2012
Creator: Dubovsky, Sergei; Senatore, Leonardo & Villadoro, Giovanni
System: The UNT Digital Library
Ab Initio Calculations Of Light-Ion Reactions (open access)

Ab Initio Calculations Of Light-Ion Reactions

The exact treatment of nuclei starting from the constituent nucleons and the fundamental interactions among them has been a long-standing goal in nuclear physics. In addition to the complex nature of nuclear forces, one faces the quantum-mechanical many-nucleon problem governed by an interplay between bound and continuum states. In recent years, significant progress has been made in ab initio nuclear structure and reaction calculations based on input from QCD employing Hamiltonians constructed within chiral effective field theory. In this contribution, we present one of such promising techniques capable of describing simultaneously both bound and scattering states in light nuclei. By combining the resonating-group method (RGM) with the ab initio no-core shell model (NCSM), we complement a microscopic cluster approach with the use of realistic interactions and a microscopic and consistent description of the clusters. We discuss applications to light nuclei scattering, radiative capture and fusion reactions.
Date: March 12, 2012
Creator: Navratil, P; Quaglioni, S; Roth, R & Horiuchi, W
System: The UNT Digital Library
Fermi Large Area Telescope Observations of the Crab Pulsar and Nebula (open access)

Fermi Large Area Telescope Observations of the Crab Pulsar and Nebula

None
Date: March 29, 2012
Creator: Abdo, A. A.; Ackermann, M.; Ajello, M.; Atwood, W. B.; Axelsson, M.; Baldini, L. et al.
System: The UNT Digital Library
Simulation and Experiment of Thermal Fatigue in the CPV Die Attach: Preprint (open access)

Simulation and Experiment of Thermal Fatigue in the CPV Die Attach: Preprint

FEM simulation and accelerated thermal cycling have been performed for the CPV die attach. Trends in fatigue damage accumulation and equivalent test time are explored and found to be most sensitive to temperature ramp rate. Die attach crack growth is measured through cycling and found to be in excellent agreement with simulations of the inelastic strain energy accumulated. Simulations of an entire year of weather data provides for the relative ranking of fatigue damage between four cites as well as their equivalent accelerated test time.
Date: May 1, 2012
Creator: Bosco, N.; Silverman, T. & Kurtz, S.
System: The UNT Digital Library
Intense Super-radiant X-rays from a Compact Source using a Nanocathode Array and Emittance Exchange (open access)

Intense Super-radiant X-rays from a Compact Source using a Nanocathode Array and Emittance Exchange

A novel method of producing intense short wavelength radiation from relativistic electrons is described. The electrons are periodically bunched at the wavelength of interest enabling in-phase super-radiant emission that is far more intense than from unbunched electrons. The periodic bunching is achieved in steps beginning with an array of beamlets emitted from a nanoengineered field emission array. The beamlets are then manipulated and converted to a longitudinal density modulation via a transverse to longitudinal emittance exchange. Periodic bunching at short wavelength is shown to be possible, and the partially coherent x-ray properties produced by Inverse Compton scattering from an intense laser are estimated. The proposed method increases the efficiency of x-ray production by several orders of magnitude, potentially enabling compact x-ray sources to produce brilliance and flux similar to major synchrotron facilities.
Date: February 1, 2012
Creator: Graves, W. S.; Kaertner, F. X.; Moncton, D. E. & Piot, P.
System: The UNT Digital Library
Fully Integrated Applications of Thin Films on Low Temperature Cofired Ceramic (LTCC) (open access)

Fully Integrated Applications of Thin Films on Low Temperature Cofired Ceramic (LTCC)

Thin film multilayers have previously been introduced on multilayer low temperature cofired ceramic (LTCC), as well as initial thin film capacitors on LTCC. The ruggedness of a multipurpose Ti-Cu-Pt-Au stack for connectivity and RF conductivity has continued to benefit fabrication and reliability in state of-the-art modules, while the capacitors have followed the traditional Metal-Insulator-Metal (MIM) style. The full integration of thin film passives with thin film connectivity traces is presented. Certain passives, such as capacitors, require specifically tailored and separately patterned thin film (multi-)layers, including a dielectric. Different capacitance values are achieved by variation of both the insulator layer thickness and the active area of the capacitor. Other passives, such as filters, require only the conductor - a single thin film multilayer. This can be patterned from the same connectivity thin film material (Ti-Cu-Pt-Au), or a specially tailored thin film material (e.g. Ti-Cu-Au) can be deposited. Both versions are described, including process and integration details. Examples are discussed, ranging from patterning for maximum tolerances, to space and performance-optimized designs. Cross-sectional issues associated with integration are also highlighted in the discussion.
Date: April 19, 2012
Creator: Wolf, Ambrose; Peterson, Ken; O'Keefe, Matt; Huebner, Wayne & Kuhn, Bill
System: The UNT Digital Library
Lorentz Force Compensation for Long Pulses in SRF Cavities (open access)

Lorentz Force Compensation for Long Pulses in SRF Cavities

None
Date: May 1, 2012
Creator: Pischalnikov, Y.; Cancelo, G.; Chase, B.; Crawford, D.; Edstrom, D.; Harms, E. et al.
System: The UNT Digital Library
UPGRADING THE CEBAF INJECTOR WITH A NEW BOOSTER, HIGHER VOLTAGE GUN, AND HIGHER FINAL ENERGY (open access)

UPGRADING THE CEBAF INJECTOR WITH A NEW BOOSTER, HIGHER VOLTAGE GUN, AND HIGHER FINAL ENERGY

The Continuous Electron Beam Accelerator Facility (CEBAF) accelerator at Jefferson Lab will be upgraded from 6 GeV to 12 GeV in the next few years. To meet the requirement of the new machine and to take the opportunity to improve the beam quality, the CEBAF injector will be upgraded with a higher voltage gun, a new booster, and a new accelerating RF module. The CEBAF injector creates and accelerates three beams at different currents simultaneously. The beams are interleaved, each at one third of the RF frequency, traveling through the same beam line. The higher voltage gun will lower the space charge effects. The new booster with optimized beam dynamics will complete the bunching process and provide initial acceleration matched to the new gun voltage. Using our latest SRF design, the new booster has significantly lower x/y coupling effects that should improve our beam setup and operation for the highly sensitive parity experiments scheduled for the CEBAF's future. Finally, the new accelerating RF module will roughly double the injector final energy to match the rest of the 12 GeV accelerator. In this paper we will provide more detail about this upgrade.
Date: July 1, 2012
Creator: Kazimi, Reza; Freyberger, Arne; Hofler, Alicia; Hutton, Andrew & Hannon, Fay
System: The UNT Digital Library
Wind Power Forecasting Error Distributions: An International Comparison; Preprint (open access)

Wind Power Forecasting Error Distributions: An International Comparison; Preprint

Wind power forecasting is expected to be an important enabler for greater penetration of wind power into electricity systems. Because no wind forecasting system is perfect, a thorough understanding of the errors that do occur can be critical to system operation functions, such as the setting of operating reserve levels. This paper provides an international comparison of the distribution of wind power forecasting errors from operational systems, based on real forecast data. The paper concludes with an assessment of similarities and differences between the errors observed in different locations.
Date: September 1, 2012
Creator: Hodge, B. M.; Lew, D.; Milligan, M.; Holttinen, H.; Sillanpaa, S.; Gomez-Lazaro, E. et al.
System: The UNT Digital Library
A Terrestrial Search for Dark Contents of the Vacuum, Such as Dark Energy, Using Atom Interferometry (open access)

A Terrestrial Search for Dark Contents of the Vacuum, Such as Dark Energy, Using Atom Interferometry

We describe the theory and first experimental work on our concept for searching on earth for the presence of dark contents of the vacuum (DCV) using atom interferometry. Specifically, we have in mind any DCV that has not yet been detected on a laboratory scale, but which might manifest itself as dark energy on the cosmological scale. The experimental method uses two atom interferometers to cancel the effect of earth's gravity and diverse noise sources. It depends upon two assumptions: first, that the DCV possesses some space inhomogeneity in density, and second that it exerts a sufficiently strong nongravitational force on matter. The motion of the apparatus through the DCV should then lead to an irregular variation in the detected matter-wave phase shift. We discuss the nature of this signal and note the problem of distinguishing it from instrumental noise. We also discuss the relation of our experiment to what might be learned by studying the noise in gravitational wave detectors such as LIGO. The paper concludes with a projection that a future search of this nature might be carried out using an atom interferometer in an orbiting satellite. The laboratory apparatus is now being constructed.
Date: June 11, 2012
Creator: Adler, Ronald J.; /Stanford U., HEPL /San Francisco State U.; Muller, Holger; /UC, Berkeley; Perl, Martin L. & /KIPAC, Menlo Park /SLAC
System: The UNT Digital Library
Compact proton spectrometers for measurements of shock (open access)

Compact proton spectrometers for measurements of shock

The compact Wedge Range Filter (WRF) proton spectrometer was developed for OMEGA and transferred to the National Ignition Facility (NIF) as a National Ignition Campaign (NIC) diagnostic. The WRF measures the spectrum of protons from D-{sup 3}He reactions in tuning-campaign implosions containing D and {sup 3}He gas; in this work we report on the first proton spectroscopy measurement on the NIF using WRFs. The energy downshift of the 14.7-MeV proton is directly related to the total {rho}R through the plasma stopping power. Additionally, the shock proton yield is measured, which is a metric of the final merged shock strength.
Date: May 2, 2012
Creator: Mackinnon, A.; Zylstra, A.; Frenje, J. A.; Seguin, F. H.; Rosenberg, M. J.; Rinderknecht, H. G. et al.
System: The UNT Digital Library