Combined Effects of Gravity, Bending Moment, Bearing Clearance, and Input Torque on Wind Turbine Planetary Gear Load Sharing: Preprint (open access)

Combined Effects of Gravity, Bending Moment, Bearing Clearance, and Input Torque on Wind Turbine Planetary Gear Load Sharing: Preprint

This computational work investigates planetary gear load sharing of three-mount suspension wind turbine gearboxes. A three dimensional multibody dynamic model is established, including gravity, bending moments, fluctuating mesh stiffness, nonlinear tooth contact, and bearing clearance. A flexible main shaft, planetary carrier, housing, and gear shafts are modeled using reduced degrees-of-freedom through modal compensation. This drivetrain model is validated against the experimental data of Gearbox Reliability Collaborative for gearbox internal loads. Planet load sharing is a combined effect of gravity, bending moment, bearing clearance, and input torque. Influences of each of these parameters and their combined effects on the resulting planet load sharing are investigated. Bending moments and gravity induce fundamental excitations in the rotating carrier frame, which can increase gearbox internal loads and disturb load sharing. Clearance in carrier bearings reduces the bearing load carrying capacity and thus the bending moment from the rotor can be transmitted into gear meshes. With bearing clearance, the bending moment can cause tooth micropitting and can induce planet bearing fatigue, leading to reduced gearbox life. Planet bearings are susceptible to skidding at low input torque.
Date: September 1, 2012
Creator: Guo, Y.; Keller, J. & LaCava, W.
System: The UNT Digital Library
Event-by-event study of photon observables in spontaneous and thermal fission (open access)

Event-by-event study of photon observables in spontaneous and thermal fission

None
Date: September 26, 2012
Creator: Vogt, R & Randrup, J
System: The UNT Digital Library
Performance Characteristics of Hardware Transactional Memory for Molecular Dynamics Application on BlueGene/Q: Toward Efficient Multithreading Strategies for Large-Scale Scientific Applications (open access)

Performance Characteristics of Hardware Transactional Memory for Molecular Dynamics Application on BlueGene/Q: Toward Efficient Multithreading Strategies for Large-Scale Scientific Applications

None
Date: September 26, 2012
Creator: Kunaseth, M.; Kalia, R. K.; Nakano, A.; Vashishta, P.; Richards, D. F. & Glosli, J. N.
System: The UNT Digital Library
Analyzing the Deployment of Large Amounts of Offshore Wind to Design an Offshore Transmission Grid in the United States: Preprint (open access)

Analyzing the Deployment of Large Amounts of Offshore Wind to Design an Offshore Transmission Grid in the United States: Preprint

This paper revisits the results from the U.S. Department of Energy's '20% Wind Energy By 2030' study, which envisioned that 54 GW of offshore wind would be installed by said year. The analysis is conducted using the Regional Energy Deployment System (ReEDS), a capacity expansion model developed by the National Renewable Energy Laboratory. The model is used to optimize the deployment of the 54 GW of wind capacity along the coasts and lakes of the United States. The graphical representation of the results through maps will be used to provide a qualitative description for planning and designing an offshore grid. ReEDS takes into account many factors in the process of siting offshore wind capacity, such as the quality of the resource, capital and O&M costs, interconnection costs, or variability metrics (wind capacity value, forecast error, expected curtailment). The effect of these metrics in the deployment of offshore wind will be analyzed through examples in the results.
Date: September 1, 2012
Creator: Ibanez, E.; Mai, T. & Coles, L.
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
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
An efficient modeling method for thermal stratification simulation in a BWR suppression pool (open access)

An efficient modeling method for thermal stratification simulation in a BWR suppression pool

The suppression pool in a BWR plant not only is the major heat sink within the containment system, but also provides major emergency cooling water for the reactor core. In several accident scenarios, such as LOCA and extended station blackout, thermal stratification tends to form in the pool after the initial rapid venting stage. Accurately predicting the pool stratification phenomenon is important because it affects the peak containment pressure; and the pool temperature distribution also affects the NPSHa (Available Net Positive Suction Head) and therefore the performance of the pump which draws cooling water back to the core. Current safety analysis codes use 0-D lumped parameter methods to calculate the energy and mass balance in the pool and therefore have large uncertainty in prediction of scenarios in which stratification and mixing are important. While 3-D CFD methods can be used to analyze realistic 3D configurations, these methods normally require very fine grid resolution to resolve thin substructures such as jets and wall boundaries, therefore long simulation time. For mixing in stably stratified large enclosures, the BMIX++ code has been developed to implement a highly efficient analysis method for stratification where the ambient fluid volume is represented by 1-D transient partial …
Date: September 1, 2012
Creator: Zhao, Haihua; Zou, Ling; Zhang, Hongbin; Li, Hua; Villanueva, Walter & Kudinov, Pavel
System: The UNT Digital Library
The 12 GeV Energy Upgrade at Jefferson Laboratory (open access)

The 12 GeV Energy Upgrade at Jefferson Laboratory

Two new cryomodules and an extensive upgrade of the bending magnets at Jefferson Lab has been recently completed in preparation for the full energy upgrade in about one year. Jefferson Laboratory has undertaken a major upgrade of its flagship facility, the CW re-circulating CEBAF linac, with the goal of doubling the linac energy to 12 GeV. I will discuss here the main scope and timeline of the upgrade and report on recent accomplishments and the present status. I will then discuss in more detail the core of the upgrade, the new additional C100 cryomodules, their production, tests and recent successful performance. I will then conclude by looking at the future plans of Jefferson Laboratory, from the commissioning and operations of the 12 GeV CEBAF to the design of the MEIC electron ion collider.
Date: September 2012
Creator: Pilat, Fulvia C.
System: The UNT Digital Library
Analog Video Authentication and Seal Verification Equipment Development (open access)

Analog Video Authentication and Seal Verification Equipment Development

Under contract to the US Department of Energy in support of arms control treaty verification activities, the Savannah River National Laboratory in conjunction with the Pacific Northwest National Laboratory, the Idaho National Laboratory and Milagro Consulting, LLC developed equipment for use within a chain of custody regime. This paper discussed two specific devices, the Authentication Through the Lens (ATL) analog video authentication system and a photographic multi-seal reader. Both of these devices have been demonstrated in a field trial, and the experience gained throughout will also be discussed. Typically, cryptographic methods are used to prove the authenticity of digital images and video used in arms control chain of custody applications. However, in some applications analog cameras are used. Since cryptographic authentication methods will not work on analog video streams, a simple method of authenticating analog video was developed and tested. A photographic multi-seal reader was developed to image different types of visual unique identifiers for use in chain of custody and authentication activities. This seal reader is unique in its ability to image various types of seals including the Cobra Seal, Reflective Particle Tags, and adhesive seals. Flicker comparison is used to compare before and after images collected with the …
Date: September 1, 2012
Creator: Lancaster, Gregory
System: The UNT Digital Library
Thoughts on polarimetry for 3He beams at RHIC (open access)

Thoughts on polarimetry for 3He beams at RHIC

N/A
Date: September 17, 2012
Creator: Makdisi, Y.
System: The UNT Digital Library
LANDSCAPE MANAGEMENT FOR SUSTAINABLE SUPPLIES OF BIOENERGY FEEDSTOCK AND ENHANCED SOIL QUALITY (open access)

LANDSCAPE MANAGEMENT FOR SUSTAINABLE SUPPLIES OF BIOENERGY FEEDSTOCK AND ENHANCED SOIL QUALITY

Agriculture can simultaneously address global food, feed, fiber, and energy challenges provided our soil, water, and air resources are not compromised in doing so. As we embark on the 19th Triennial Conference of the International Soil and Tillage Research Organization (ISTRO), I am pleased to proclaim that our members are well poised to lead these endeavors because of our comprehensive understanding of soil, water, agricultural and bio-systems engineering processes. The concept of landscape management, as an approach for integrating multiple bioenergy feedstock sources, including biomass residuals, into current crop production systems, is used as the focal point to show how these ever-increasing global challenges can be met in a sustainable manner. Starting with the 2005 Billion Ton Study (BTS) goals, research and technology transfer activities leading to the 2011 U.S. Department of Energy (DOE) Revised Billion Ton Study (BT2) and development of a residue management tool to guide sustainable crop residue harvest will be reviewed. Multi-location USDA-Agricultural Research Service (ARS) Renewable Energy Assessment Project (REAP) team research and on-going partnerships between public and private sector groups will be shared to show the development of landscape management strategies that can simultaneously address the multiple factors that must be balanced to meet …
Date: September 1, 2012
Creator: Karlen, Douglas L. & David J. Muth, Jr.
System: The UNT Digital Library
NUCLEAR ENERGY SYSTEM COST MODELING (open access)

NUCLEAR ENERGY SYSTEM COST MODELING

The U.S. Department of Energy’s Fuel Cycle Technologies (FCT) Program is preparing to perform an evaluation of the full range of possible Nuclear Energy Systems (NES) in 2013. These include all practical combinations of fuels and transmuters (reactors and sub-critical systems) in single and multi-tier combinations of burners and breeders with no, partial, and full recycle. As part of this evaluation, Levelized Cost of Electricity at Equilibrium (LCAE) ranges for each representative system will be calculated. To facilitate the cost analyses, the 2009 Advanced Fuel Cycle Cost Basis Report is being amended to provide up-to-date cost data for each step in the fuel cycle, and a new analysis tool, NE-COST, has been developed. This paper explains the innovative “Island” approach used by NE-COST to streamline and simplify the economic analysis effort and provides examples of LCAE costs generated. The Island approach treats each transmuter (or target burner) and the associated fuel cycle facilities as a separate analysis module, allowing reuse of modules that appear frequently in the NES options list. For example, a number of options to be screened will include a once-through uranium oxide (UOX) fueled light water reactor (LWR). The UOX LWR may be standalone, or may be …
Date: September 1, 2012
Creator: Ganda, Francesco & Dixon, Brent
System: The UNT Digital Library
NIF Ignition Campaign Target Performance and Requirements: Status May 2012 (open access)

NIF Ignition Campaign Target Performance and Requirements: Status May 2012

None
Date: September 10, 2012
Creator: Haan, S. W.; Atherton, J.; Clark, D. S.; Hammel, B. A.; Callahan, D. A.; Cerjan, C. J. et al.
System: The UNT Digital Library
3D Simulation of Missing Pellet Surface Defects in Light Water Reactor Fuel Rods (open access)

3D Simulation of Missing Pellet Surface Defects in Light Water Reactor Fuel Rods

The cladding on light water reactor (LWR) fuel rods provides a stable enclosure for fuel pellets and serves as a first barrier against fission product release. Consequently, it is important to design fuel to prevent cladding failure due to mechanical interactions with fuel pellets. Cladding stresses can be effectively limited by controlling power increase rates. However, it has been shown that local geometric irregularities caused by manufacturing defects known as missing pellet surfaces (MPS) in fuel pellets can lead to elevated cladding stresses that are sufficiently high to cause cladding failure. Accurate modeling of these defects can help prevent these types of failures. Nuclear fuel performance codes commonly use a 1.5D (axisymmetric, axially-stacked, one-dimensional radial) or 2D axisymmetric representation of the fuel rod. To study the effects of MPS defects, results from 1.5D or 2D fuel performance analyses are typically mapped to thermo-mechanical models that consist of a 2D plane-strain slice or a full 3D representation of the geometry of the pellet and clad in the region of the defect. The BISON fuel performance code developed at Idaho National Laboratory employs either a 2D axisymmetric or 3D representation of the full fuel rod. This allows for a computational model of …
Date: September 1, 2012
Creator: Spencer, B. W.; Hales, J. D.; Novascone, S. R. & Williamson, R. L.
System: The UNT Digital Library
Compact, Inexpensive, Safe, and Rapidly Refuelable Hydrogen Storage in Cryogenic Pressure Vessels (open access)

Compact, Inexpensive, Safe, and Rapidly Refuelable Hydrogen Storage in Cryogenic Pressure Vessels

None
Date: September 21, 2012
Creator: Aceves, S. M.; Petitpas, G.; Espinosa-Loza, F.; Matthews, M. J. & Ledesma-Orozco, E.
System: The UNT Digital Library
Formic Acid Free Flowsheet Development To Eliminate Catalytic Hydrogen Generation In The Defense Waste Processing (open access)

Formic Acid Free Flowsheet Development To Eliminate Catalytic Hydrogen Generation In The Defense Waste Processing

The Defense Waste Processing Facility (DWPF) processes legacy nuclear waste generated at the Savannah River Site (SRS) during production of plutonium and tritium demanded by the Cold War. The nuclear waste is first treated via a complex sequence of controlled chemical reactions and then vitrified into a borosilicate glass form and poured into stainless steel canisters. Converting the nuclear waste into borosilicate glass canisters is a safe, effective way to reduce the volume of the waste and stabilize the radionuclides. Testing was initiated to determine whether the elimination of formic acid from the DWPF's chemical processing flowsheet would eliminate catalytic hydrogen generation. Historically, hydrogen is generated in chemical processing of alkaline High Level Waste sludge in DWPF. In current processing, sludge is combined with nitric and formic acid to neutralize the waste, reduce mercury and manganese, destroy nitrite, and modify (thin) the slurry rheology. The noble metal catalyzed formic acid decomposition produces hydrogen and carbon dioxide. Elimination of formic acid by replacement with glycolic acid has the potential to eliminate the production of catalytic hydrogen. Flowsheet testing was performed to develop the nitric-glycolic acid flowsheet as an alternative to the nitric-formic flowsheet currently being processed at the DWPF. This new …
Date: September 14, 2012
Creator: Lambert, Dan P.; Stone, Michael E.; Newell, J. David; Fellinger, Terri L. & Bricker, Jonathan M.
System: The UNT Digital Library
Developing of superconducting RF guns at BNL (open access)

Developing of superconducting RF guns at BNL

N/A
Date: September 9, 2012
Creator: Belomestnykh, S.; Altinbas, Z.; Ben-Zvi, Ilan; Boulware, C. H.; Brutus, J. C.; Burrill, A. et al.
System: The UNT Digital Library
Re-architecting TEIMS Web-based Legacy Applications Using the Model View Controller Paradigm (open access)

Re-architecting TEIMS Web-based Legacy Applications Using the Model View Controller Paradigm

None
Date: September 5, 2012
Creator: Barbosa, E & Laguna, G W
System: The UNT Digital Library
Modeling Ion-Exchange Processing With Spherical Resins For Cesium Removal (open access)

Modeling Ion-Exchange Processing With Spherical Resins For Cesium Removal

The spherical Resorcinol-Formaldehyde and hypothetical spherical SuperLig(r) 644 ion-exchange resins are evaluated for cesium removal from radioactive waste solutions. Modeling results show that spherical SuperLig(r) 644 reduces column cycling by 50% for high-potassium solutions. Spherical Resorcinol Formaldehyde performs equally well for the lowest-potassium wastes. Less cycling reduces nitric acid usage during resin elution and sodium addition during resin regeneration, therefore, significantly decreasing life-cycle operational costs. A model assessment of the mechanism behind ''cesium bleed'' is also conducted. When a resin bed is eluted, a relatively small amount of cesium remains within resin particles. Cesium can bleed into otherwise decontaminated product in the next loading cycle. The bleed mechanism is shown to be fully isotherm-controlled vs. mass transfer controlled. Knowledge of residual post-elution cesium level and resin isotherm can be utilized to predict rate of cesium bleed in a mostly non-loaded column. Overall, this work demonstrates the versatility of the ion-exchange modeling to study the effects of resin characteristics on processing cycles, rates, and cold chemical consumption. This evaluation justifies further development of a spherical form of the SL644 resin.
Date: September 19, 2012
Creator: Hang, T.; Nash, C. A. & Aleman, S. E.
System: The UNT Digital Library
Impedances and Wake Functions for Non-Ultrarelativistic Beams in Circular Chambers (open access)

Impedances and Wake Functions for Non-Ultrarelativistic Beams in Circular Chambers

None
Date: September 1, 2012
Creator: Macridin, Alexandru; Spentzouris, Panagiotis & Amundson, James
System: The UNT Digital Library
Ab-initio calculation of optical properties of wurtzitic In_x Ga_1x N and In_x Al_1x N alloys including excitonic effects (open access)

Ab-initio calculation of optical properties of wurtzitic In_x Ga_1x N and In_x Al_1x N alloys including excitonic effects

None
Date: September 5, 2012
Creator: de Carvalho, L C; Schleife, A; Furthmueller, J & Bechstedt, F
System: The UNT Digital Library
Performance Modeling of Algebraic Multigrid on Blue Gene/Q: Lessons Learned (open access)

Performance Modeling of Algebraic Multigrid on Blue Gene/Q: Lessons Learned

None
Date: September 9, 2012
Creator: Gahvari, H.; Gropp, W.; Jordan, K. E.; Schulz, M. & Yang, U. M.
System: The UNT Digital Library
QCD and Heavy Quark Physics at the Tevatron (open access)

QCD and Heavy Quark Physics at the Tevatron

None
Date: September 1, 2012
Creator: Wolbers, Stephen
System: The UNT Digital Library
USING CFD TO ANALYZE NUCLEAR SYSTEMS BEHAVIOR: DEFINING THE VALIDATION REQUIREMENTS (open access)

USING CFD TO ANALYZE NUCLEAR SYSTEMS BEHAVIOR: DEFINING THE VALIDATION REQUIREMENTS

A recommended protocol to formulate numeric tool specifications and validation needs in concert with practices accepted by regulatory agencies for advanced reactors is described. The protocol is based on the plant type and perceived transient and accident envelopes that translates to boundary conditions for a process that gives the: (a) key phenomena and figures-of-merit which must be analyzed to ensure that the advanced plant can be licensed, (b) specification of the numeric tool capabilities necessary to perform the required analyses—including bounding calculational uncertainties, and (c) specification of the validation matrices and experiments--including the desired validation data. The result of applying the process enables a complete program to be defined, including costs, for creating and benchmarking transient and accident analysis methods for advanced reactors. By following a process that is in concert with regulatory agency licensing requirements from the start to finish, based on historical acceptance of past licensing submittals, the methods derived and validated have a high probability of regulatory agency acceptance.
Date: September 1, 2012
Creator: Schultz, Richard
System: The UNT Digital Library