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Loads Analysis of Several Offshore Floating Wind Turbine Concepts (open access)

Loads Analysis of Several Offshore Floating Wind Turbine Concepts

This paper presents a comprehensive dynamic-response analysis of six offshore floating wind turbine concepts.
Date: October 1, 2011
Creator: Robertson, A. N. & Jonkman, J. M.
System: The UNT Digital Library
Structural Design of a Horizontal-Axis Tidal Current Turbine Composite Blade (open access)

Structural Design of a Horizontal-Axis Tidal Current Turbine Composite Blade

This paper describes the structural design of a tidal composite blade. The structural design is preceded by two steps: hydrodynamic design and determination of extreme loads. The hydrodynamic design provides the chord and twist distributions along the blade length that result in optimal performance of the tidal turbine over its lifetime. The extreme loads, i.e. the extreme flap and edgewise loads that the blade would likely encounter over its lifetime, are associated with extreme tidal flow conditions and are obtained using a computational fluid dynamics (CFD) software. Given the blade external shape and the extreme loads, we use a laminate-theory-based structural design to determine the optimal layout of composite laminas such that the ultimate-strength and buckling-resistance criteria are satisfied at all points in the blade. The structural design approach allows for arbitrary specification of the chord, twist, and airfoil geometry along the blade and an arbitrary number of shear webs. In addition, certain fabrication criteria are imposed, for example, each composite laminate must be an integral multiple of its constituent ply thickness. In the present effort, the structural design uses only static extreme loads; dynamic-loads-based fatigue design will be addressed in the future. Following the blade design, we compute the …
Date: October 1, 2011
Creator: Bir, G. S.; Lawson, M. J. & Li, Y.
System: The UNT Digital Library
Dynamical coupled-channels study of meson production reactions from EBAC@Jlab (open access)

Dynamical coupled-channels study of meson production reactions from EBAC@Jlab

We present the current status of a combined and simultaneous analysis of meson production reactions based on a dynamical coupled-channels (DCC) model, which is conducted at Excited Baryon Analysis Center (EBAC) of Jefferson Lab.
Date: October 1, 2011
Creator: Kamano, Hiroyuki
System: The UNT Digital Library
RADIATION DOSE ASSESSMENT FOR THE BIOTA OF TERRESTRIAL ECOSYSTEMS IN THE SHORELINE ZONE OF THE CHERNOBYL NUCLEAR POWER PLANT COOLING POND (open access)

RADIATION DOSE ASSESSMENT FOR THE BIOTA OF TERRESTRIAL ECOSYSTEMS IN THE SHORELINE ZONE OF THE CHERNOBYL NUCLEAR POWER PLANT COOLING POND

Radiation exposure of the biota in the shoreline area of the Chernobyl Nuclear Power Plant Cooling Pond was assessed to evaluate radiological consequences from the decommissioning of the Cooling Pond. The article addresses studies of radioactive contamination of the terrestrial faunal complex and radionuclide concentration ratios in bodies of small birds, small mammals, amphibians, and reptiles living in the area. The data were used to calculate doses to biota using the ERICA Tool software. Doses from {sup 90}Sr and {sup 137}Cs were calculated using the default parameters of the ERICA Tool and were shown to be consistent with biota doses calculated from the field data. However, the ERICA dose calculations for plutonium isotopes were much higher (2-5 times for small mammals and 10-14 times for birds) than the doses calculated using the experimental data. Currently, the total doses for the terrestrial biota do not exceed maximum recommended levels. However, if the Cooling Pond is allowed to drawdown naturally and the contaminants of the bottom sediments are exposed and enter the biological cycle, the calculated doses to biota may exceed the maximum recommended values. The study is important in establishing the current exposure conditions such that a baseline exists from which …
Date: October 1, 2011
Creator: Farfan, E. & Jannik, T.
System: The UNT Digital Library
Ongoing Space Nuclear Systems Development in the United States (open access)

Ongoing Space Nuclear Systems Development in the United States

Reliable, long-life power systems are required for ambitious space exploration missions. Nuclear power and propulsion options can enable a bold, new set of missions and introduce propulsion capabilities to achieve access to science destinations that are not possible with more conventional systems. Space nuclear power options can be divided into three main categories: radioisotope power for heating or low power applications; fission power systems for non-terrestrial surface application or for spacecraft power; and fission power systems for electric propulsion or direct thermal propulsion. Each of these areas has been investigated in the United States since the 1950s, achieving various stages of development. While some nuclear systems have achieved flight deployment, others continue to be researched today. This paper will provide a brief overview of historical space nuclear programs in the U.S. and will provide a summary of the ongoing space nuclear systems research, development, and deployment in the United States.
Date: October 1, 2011
Creator: Bragg-Sitton, S.; Werner, J.; Johnson, S.; Houts, Michael G.; Palac, Donald T.; Mason, Lee S. et al.
System: The UNT Digital Library
Effect of Ambient Design Temperature on Air-Cooled Binary Plant Output (open access)

Effect of Ambient Design Temperature on Air-Cooled Binary Plant Output

Air-cooled binary plants are designed to provide a specified level of power production at a particular air temperature. Nominally this air temperature is the annual mean or average air temperature for the plant location. This study investigates the effect that changing the design air temperature has on power generation for an air-cooled binary plant producing power from a resource with a declining production fluid temperature and fluctuating ambient temperatures. This analysis was performed for plants operating both with and without a geothermal fluid outlet temperature limit. Aspen Plus process simulation software was used to develop optimal air-cooled binary plant designs for specific ambient temperatures as well as to rate the performance of the plant designs at off-design operating conditions. Results include calculation of annual and plant lifetime power generation as well as evaluation of plant operating characteristics, such as improved power generation capabilities during summer months when electric power prices are at peak levels.
Date: October 1, 2011
Creator: Wendt, Dan & Mines, Greg
System: The UNT Digital Library
Wind Turbine Drivetrain Condition Monitoring - An Overview (open access)

Wind Turbine Drivetrain Condition Monitoring - An Overview

This paper provides an overview of wind turbine drivetrain condition monitoring based on presentations from a condition monitoring workshop organized by the National Renewable Energy Laboratory in 2009 and on additional references.
Date: October 1, 2011
Creator: Sheng, S. & Veers, P.
System: The UNT Digital Library
A low-power wave union TDC implemented in FPGA (open access)

A low-power wave union TDC implemented in FPGA

A low-power time-to-digital convertor (TDC) for an application inside a vacuum has been implemented based on the Wave Union TDC scheme in a low-cost field programmable gate array (FPGA) device. Bench top tests have shown that a time measurement resolution better than 30 ps (standard deviation of time differences between two channels) is achieved. Special firmware design practices are taken to reduce power consumption. The measurements indicate that with 32 channels fitting in the FPGA device, the power consumption on the FPGA core voltage is approximately 9.3 mW/channel and the total power consumption including both core and I/O banks is less than 27 mW/channel.
Date: October 1, 2011
Creator: Wu, Jinyuan; Shi, Yanchen & Zhu, Douglas
System: The UNT Digital Library
EDITORIAL HPJ SPECIAL ISSUE DEDICATION (open access)

EDITORIAL HPJ SPECIAL ISSUE DEDICATION

This issue is dedicated to the heroes and professionals who helped protect the world from nuclear disasters and to those who were displaced by these catastrophes.
Date: October 1, 2011
Creator: Farfan, E.
System: The UNT Digital Library
Review of Heavy Flavor Physics at the Tevatron (open access)

Review of Heavy Flavor Physics at the Tevatron

The D0 and CDF detectors at the Fermilab Tevatron have each accumulated more that 9 fb{sup -1} of integrated luminosity. The corresponding large datasets enable the two experiments to perform unprecedented studies of heavy flavor hadron properties. We present recent D0 and CDF measurements, focusing on rare decays and CP violation in B-meson decays. Flavor Physics probes new phenomena by either searching for small deviations from the Standard Model (SM) based theoretical predictions or by measuring quantities which are highly suppressed within the SM. Searching for small deviations from the SM are performed using large strange, charm or bottom hadron samples, mostly by kaon experiments of B factories. Measurements of highly suppressed quantities, such as CP violation phases and asymmetries in the neutral B{sub s}-meson system or searches for rare B decays, are performed with the hope that new physics effects would be large enough to significantly affect the measured quantities and so, lead to observations of deviations from the SM expectations. The D0 and CDF detectors at the Fermilab Tevatron have each accumulated more that 9 fb{sup -1} of integrated luminosity. The corresponding large datasets enable the two experiments to perform unprecedented studies of heavy flavor hadron properties. We …
Date: October 1, 2011
Creator: Giurgiu, Gavril
System: The UNT Digital Library
ILC Root tracker and vertex detector response to MARS15 simulated backgrounds in muon collider (open access)

ILC Root tracker and vertex detector response to MARS15 simulated backgrounds in muon collider

Results from a simulation of the background for a muon collider, and the response of a silicon tracking detector to this background are presented. The background caused by decays of the 750-GeV muon beams was simulated using the MARS15 program, which included the infrastructure of the beam line elements near the detector and the 10{sup o} nozzles that shield the detector from this background. The ILCRoot framework, along with the Geant4 program, was used to simulate the response of the tracker and vertex silicon detectors to the muon-decay background remaining after the shielding nozzles. Results include the hit distributions in these detectors, the fractions of type-specific background particles producing these hits and illustrate the use of timing of the hits to suppress the muon beam background.
Date: October 1, 2011
Creator: Terentiev, N. K.; Di Benedetto, V.; Gatto, C.; Mazzacane, A.; Mokhov, N. V. & Striganov, S. I.
System: The UNT Digital Library
Neutral Current Elastic Interactions in MiniBooNE (open access)

Neutral Current Elastic Interactions in MiniBooNE

Neutral Current Elastic (NCE) interactions in MiniBooNE are discussed. In the neutrino mode MiniBooNE reported: the flux averaged NCE differential cross section as a function of four-momentum transferred squared, an axial mass (M{sub A}) measurement, and a measurement of the strange quark spin content of the nucleon, {Delta}s. In the antineutrino mode we present the background-subtracted data which is compared with the Monte Carlo predictions.
Date: October 1, 2011
Creator: Dharmapalan, Ranjan
System: The UNT Digital Library
Nonlinear integrable ion traps (open access)

Nonlinear integrable ion traps

Quadrupole ion traps can be transformed into nonlinear traps with integrable motion by adding special electrostatic potentials. This can be done with both stationary potentials (electrostatic plus a uniform magnetic field) and with time-dependent electric potentials. These potentials are chosen such that the single particle Hamilton-Jacobi equations of motion are separable in some coordinate systems. The electrostatic potentials have several free adjustable parameters allowing for a quadrupole trap to be transformed into, for example, a double-well or a toroidal-well system. The particle motion remains regular, non-chaotic, integrable in quadratures, and stable for a wide range of parameters. We present two examples of how to realize such a system in case of a time-independent (the Penning trap) as well as a time-dependent (the Paul trap) configuration.
Date: October 1, 2011
Creator: Nagaitsev, S. & Danilov, V.
System: The UNT Digital Library
E3: Education, Experience, Employment The Economic Ladder to Success (open access)

E3: Education, Experience, Employment The Economic Ladder to Success

Science, Technology, Engineering, and Math (STEM) literate citizenry is critical for Idaho's economy to effectively compete and grow in today's global marketplace and enhance Idaho workforce capabilities. Idaho's blueprint presents a collaboration design developed by a group of Idaho stakeholders including state level (STEM) educators, state and federal government, other agencies, and industry across the state. The purpose the Idaho Learn and Earn Blueprint Design is to describe a comprehensive plan for improving STEM education in Idaho through a collaborative partnerships and a series of grant supported projects underpinning this strategic design process building pathways to overcome hurdles in today's economy, and moving communities and families up their economic ladder. The Idaho Learn and Earn Blueprint Design focuses on three industry sectors; energy, advanced manufacturing, and health care. All are important in Idaho and have room for job growth potential among both displaced workers and graduates. Representatives from each sector are members of the design team and assist in developing grants and implementing the actions outlined in the design as the program goes forward. Idaho's current programs are generally institution specific. Each of the state's two-year colleges, along with regional groups and employers, are already working towards improving STEM education …
Date: October 1, 2011
Creator: Seifert, Anne L
System: The UNT Digital Library
Effect of Mixed Working Fluid Composition on Binary Cycle Condenser Heat Transfer Coefficients (open access)

Effect of Mixed Working Fluid Composition on Binary Cycle Condenser Heat Transfer Coefficients

Effect of Mixed Working Fluid Composition on Binary Cycle Condenser Heat Transfer Coefficients Dan Wendt, Greg Mines Idaho National Laboratory The use of mixed working fluids in binary power plants can provide significant increases in plant performance, provided the heat exchangers are designed to take advantage of these fluids non-isothermal phase changes. In the 1980's testing was conducted at DOE's Heat Cycle Research Facility (HCRF) where mixtures of different compositions were vaporized at supercritical pressures and then condensed. This testing had focused on using the data collected to verify that Heat Transfer Research Incorporated (HTRI) codes were suitable for the design of heat exchangers that could be used with mixtures. The HCRF data includes mixture compositions varying from 0% to 40% isopentane and condenser tube orientations of 15{sup o}, 60{sup o}, and 90{sup o} from horizontal. Testing was performed over a range of working fluid and cooling fluid conditions. Though the condenser used in this testing was water cooled, the working fluid condensation occurred on the tube-side of the heat exchanger. This tube-side condensation is analogous to that in an air-cooled condenser. Tube-side condensing heat transfer coefficient information gleaned from the HCRF testing is used in this study to assess …
Date: October 1, 2011
Creator: Wendt, Dan & Mines, Greg
System: The UNT Digital Library
SOLVENT EXTRACTION RESEARCH AND DEVELOPMENT IN THE U.S. FUEL CYCLE PROGRAM (open access)

SOLVENT EXTRACTION RESEARCH AND DEVELOPMENT IN THE U.S. FUEL CYCLE PROGRAM

Treatment or processing of used nuclear fuel to recycle uranium and plutonium has historically been accomplished using the well known PUREX process. The PUREX process has been used on an industrial scale for over 60 years in the nuclear industry. Research is underway to develop advanced separation methods for the recovery of other used fuel components, such as the minor actinides (Np, Am, Cm) for possible transmutation in fast spectrum reactors, or other constituents (e.g. Cs, Sr, transition metals, lanthanides) to help facilitate effective waste management options. This paper will provide an overview of new solvent extraction processes developed for advanced nuclear fuel cycles, and summarize recent experimental results. This will include the utilization of new extractants for selective separation of target metals and new processes developed to selectively recover one or more elements from used fuel.
Date: October 1, 2011
Creator: Todd, Terry A.
System: The UNT Digital Library
The lightest hybrid meson supermultiplet in QCD (open access)

The lightest hybrid meson supermultiplet in QCD

We interpret the spectrum of meson states recently obtained in non-perturbative lattice QCD calculations in terms of constituent quark-antiquark bound states and states, called 'hybrids', in which the q{bar q} pair is supplemented by an excitation of the gluonic field. We identify a lightest supermultiplet of hybrid mesons with J{sup PC} = (0,1,2){sup {-+}}, 1{sup -} built from a gluonic excitation of chromomagnetic character coupled to q{bar q} in an S-wave. The next lightest hybrids are suggested to be quark orbital excitations with the same gluonic excitation, while the next distinct gluonic excitation is significantly heavier. Existing models of gluonic excitations are compared to these findings and possible phenomenological consequences explored.
Date: October 1, 2011
Creator: Dudek, Jozef J.
System: The UNT Digital Library
CONTRIBUTING TO THE DISCUSSIONS ON THE FUNDAMENTAL ASPECTS AND COMPLEXITIES OF TALSPEAK CHEMISTRY (open access)

CONTRIBUTING TO THE DISCUSSIONS ON THE FUNDAMENTAL ASPECTS AND COMPLEXITIES OF TALSPEAK CHEMISTRY

When liquid-liquid distribution of lanthanides was monitored at Talspeak-related conditions a characteristic drop in the extraction efficiency was observed at high lactate concentrations. The lactate dependency trend also appears to be directly affected by the increasing complexity of the non-aqueous environment. Some considerations of the non-ideal solution behavior in aqueous and organic environment are presented here in an attempt to explain the observed metal partitioning trends. While the mechanism of metal ion phase transfer appears to adhere to the conventional thermodynamic struggle between HDEHP and DTPA, the diminished metal distribution and suppressed slopes for the extractant dependencies suggest further build-up in the complexity of the non-aqueous environment in Talspeak systems.
Date: October 1, 2011
Creator: Zalupski, Peter R. & Martin, Leigh R.
System: The UNT Digital Library
Investigating the Influence of the Added Mass Effect to Marine Hydrokinetic Horizontal-Axis Turbines Using a General Dynamic Wake Wind Turbine Code (open access)

Investigating the Influence of the Added Mass Effect to Marine Hydrokinetic Horizontal-Axis Turbines Using a General Dynamic Wake Wind Turbine Code

This paper describes a recent study to investigate the applicability of a horizontal-axis wind turbine (HAWT) structural dynamics and unsteady aerodynamics analysis program (FAST and AeroDyn respectively) to modeling the forces on marine hydrokinetic (MHK) turbines. This paper summarizes the added mass model that has been added to AeroDyn. The added mass model only includes flow acceleration perpendicular to the rotor disc, and ignores added mass forces caused by blade deflection. A model of the National Renewable Energy Laboratory's (NREL) Unsteady Aerodynamics Experiment (UAE) Phase VI wind turbine was analyzed using FAST and AeroDyn with sea water conditions and the new added mass model. The results of this analysis exhibited a 3.6% change in thrust for a rapid pitch case and a slight change in amplitude and phase of thrust for a case with 30{sup o} of yaw.
Date: October 1, 2011
Creator: Maniaci, D. C. & Li, Y.
System: The UNT Digital Library
ASSESSMENT OF 90SR AND 137CS PENETRATION INTO REINFORCED CONCRETE (EXTENT OF 'DEEPENING') UNDER NATURAL ATMOSPHERIC CONDITIONS (open access)

ASSESSMENT OF 90SR AND 137CS PENETRATION INTO REINFORCED CONCRETE (EXTENT OF 'DEEPENING') UNDER NATURAL ATMOSPHERIC CONDITIONS

When assessing the feasibility of remediation following the detonation of a radiological dispersion device or improvised nuclear device in a large city, several issues should be considered including the levels and characteristics of the radioactive contamination, the availability of resources required for decontamination, and the planned future use of the city's structures and buildings. Currently, little is known about radionuclide penetration into construction materials in an urban environment. Knowledge in this area would be useful when considering costs of a thorough decontamination of buildings, artificial structures, and roads in an affected urban environment. Pripyat, a city substantially contaminated by the Chernobyl Nuclear Power Plant accident in April 1986, may provide some answers. The main objective of this study was to assess the depth of {sup 90}Sr and {sup 137}Cs penetration into reinforced concrete structures in a highly contaminated urban environment under natural weather conditions. Thirteen reinforced concrete core samples were obtained from external surfaces of a contaminated building in Pripyat. The concrete cores were drilled to obtain sample layers of 0-5, 5-10, 10-15, 15-20, 20-30, 30-40, and 40-50 mm. Both {sup 90}Sr and {sup 137}Cs were detected in the entire 0-50 mm profile of the reinforced cores sampled. In most …
Date: October 1, 2011
Creator: Farfan, E. & Jannik, T.
System: The UNT Digital Library
The Consortium for Advanced Simulation of Light Water Reactors (open access)

The Consortium for Advanced Simulation of Light Water Reactors

The Consortium for Advanced Simulation of Light Water Reactors (CASL) is a DOE Energy Innovation Hub for modeling and simulation of nuclear reactors. It brings together an exceptionally capable team from national labs, industry and academia that will apply existing modeling and simulation capabilities and develop advanced capabilities to create a usable environment for predictive simulation of light water reactors (LWRs). This environment, designated as the Virtual Environment for Reactor Applications (VERA), will incorporate science-based models, state-of-the-art numerical methods, modern computational science and engineering practices, and uncertainty quantification (UQ) and validation against data from operating pressurized water reactors (PWRs). It will couple state-of-the-art fuel performance, neutronics, thermal-hydraulics (T-H), and structural models with existing tools for systems and safety analysis and will be designed for implementation on both today's leadership-class computers and the advanced architecture platforms now under development by the DOE. CASL focuses on a set of challenge problems such as CRUD induced power shift and localized corrosion, grid-to-rod fretting fuel failures, pellet clad interaction, fuel assembly distortion, etc. that encompass the key phenomena limiting the performance of PWRs. It is expected that much of the capability developed will be applicable to other types of reactors. CASL's mission is to …
Date: October 1, 2011
Creator: Szilard, Ronaldo; Zhang, Hongbin; Kothe, Doug & Turinsky, Paul
System: The UNT Digital Library
Dynamic Analysis of Electrical Power Grid Delivery: Using Prime Mover Engines to Balance Dynamic Wind Turbine Output (open access)

Dynamic Analysis of Electrical Power Grid Delivery: Using Prime Mover Engines to Balance Dynamic Wind Turbine Output

This paper presents an investigation into integrated wind + combustion engine high penetration electrical generation systems. Renewable generation systems are now a reality of electrical transmission. Unfortunately, many of these renewable energy supplies are stochastic and highly dynamic. Conversely, the existing national grid has been designed for steady state operation. The research team has developed an algorithm to investigate the feasibility and relative capability of a reciprocating internal combustion engine to directly integrate with wind generation in a tightly coupled Hybrid Energy System. Utilizing the Idaho National Laboratory developed Phoenix Model Integration Platform, the research team has coupled demand data with wind turbine generation data and the Aspen Custom Modeler reciprocating engine electrical generator model to investigate the capability of reciprocating engine electrical generation to balance stochastic renewable energy.
Date: October 1, 2011
Creator: Grauer, Diana K.
System: The UNT Digital Library
Preliminary Results of a RANS Simulation for a Floating Point Absorber Wave Energy System Under Extreme Wave Conditions (open access)

Preliminary Results of a RANS Simulation for a Floating Point Absorber Wave Energy System Under Extreme Wave Conditions

This paper presents the results of a preliminary study on the hydrodynamics of a moored floating-point absorber (FPA) wave energy system under extreme wave conditions.
Date: October 1, 2011
Creator: Yu, Y. & Li, Y.
System: The UNT Digital Library
Radio frequency phototube and optical clock: High resolution, high rate and highly stable single photon timing technique (open access)

Radio frequency phototube and optical clock: High resolution, high rate and highly stable single photon timing technique

A new timing technique for single photons based on the radio frequency phototube and optical clock or femtosecond optical frequency comb generator is proposed. The technique has a 20 ps resolution for single photons, is capable of operating with MHz frequencies and achieving 10 fs instability level.
Date: October 1, 2011
Creator: Margaryan, Amur
System: The UNT Digital Library