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AdS/QCD, Light-Front Holography, and Color Confinement (open access)

AdS/QCD, Light-Front Holography, and Color Confinement

This report talks about the AdS/QCD, Light-Front Holography, and Color Confinement
Date: February 1, 2013
Creator: Brodsky, Stanley J. & Teramond, Guy F. de
System: The UNT Digital Library
Advanced Platform for Development and Evaluation of Grid Interconnection Systems Using Hardware-in-the-Loop (Poster) (open access)

Advanced Platform for Development and Evaluation of Grid Interconnection Systems Using Hardware-in-the-Loop (Poster)

This poster describes a Grid Interconnection System Evaluator (GISE) that leverages hardware-in-the-loop (HIL) simulation techniques to rapidly evaluate the grid interconnection standard conformance of an ICS according to the procedures in IEEE Std 1547.1TM. The architecture and test sequencing of this evaluation tool, along with a set of representative ICS test results from three different photovoltaic (PV) inverters, are presented. The GISE adds to the National Renewable Energy Laboratory's (NREL) evaluation platform that now allows for rapid development of ICS control algorithms using controller HIL (CHIL) techniques, the ability to test the dc input characteristics of PV-based ICSs through the use of a PV simulator capable of simulating real-world dynamics using power HIL (PHIL), and evaluation of ICS grid interconnection conformance.
Date: February 1, 2013
Creator: Lundstrom, B.; Shirazi, M. & Coddington, M.
System: The UNT Digital Library
ANALYSIS OF OPERATIONAL STRATEGIES FOR UTILIZING CO2 FOR GEOTHERMAL ENERGY PRODUCTION (open access)

ANALYSIS OF OPERATIONAL STRATEGIES FOR UTILIZING CO2 FOR GEOTHERMAL ENERGY PRODUCTION

None
Date: February 1, 2013
Creator: Buscheck, T A; Chen, M; Lu, C; Sun, Y; Hao, Y; Celia, M A et al.
System: The UNT Digital Library
Benchmark Evaluation of the Medium-Power Reactor Experiment Program Critical Configurations (open access)

Benchmark Evaluation of the Medium-Power Reactor Experiment Program Critical Configurations

A series of small, compact critical assembly (SCCA) experiments were performed in 1962-1965 at the Oak Ridge National Laboratory Critical Experiments Facility (ORCEF) for the Medium-Power Reactor Experiment (MPRE) program. The MPRE was a stainless-steel clad, highly enriched uranium (HEU)-O2 fuelled, BeO reflected reactor design to provide electrical power to space vehicles. Cooling and heat transfer were to be achieved by boiling potassium in the reactor core and passing vapor directly through a turbine. Graphite- and beryllium-reflected assemblies were constructed at ORCEF to verify the critical mass, power distribution, and other reactor physics measurements needed to validate reactor calculations and reactor physics methods. The experimental series was broken into three parts, with the third portion of the experiments representing the beryllium-reflected measurements. The latter experiments are of interest for validating current reactor design efforts for a fission surface power reactor. The entire series has been evaluated as acceptable benchmark experiments and submitted for publication in the International Handbook of Evaluated Criticality Safety Benchmark Experiments and in the International Handbook of Evaluated Reactor Physics Benchmark Experiments.
Date: February 1, 2013
Creator: Marshall, Margaret A. & Bess, John D.
System: The UNT Digital Library
Determination of solvation descriptors for terpene hydrocarbons from chromatographic measurements (open access)

Determination of solvation descriptors for terpene hydrocarbons from chromatographic measurements

This article discusses the determination of solvation descriptors for terpene hydrocarbons from chromatographic measurements.
Date: February 2013
Creator: Abraham, M. H. (Michael H.); Gola, Joelle R. M.; Gil-Lostes, Javier; Acree, William E. (William Eugene) & Cometto-Muñiz, J. Enrique
System: The UNT Digital Library
Development of the Variable Atmosphere Testing Facility for Blow-Down Analysis of the Mars Hopper Prototype (open access)

Development of the Variable Atmosphere Testing Facility for Blow-Down Analysis of the Mars Hopper Prototype

Recent developments at the Center for Space Nuclear Research (CSNR) on a Martian exploration probe have lead to the assembly of a multi-functional variable atmosphere testing facility (VATF). The VATF has been assembled to perform transient blow-down analysis of a radioisotope thermal rocket (RTR) concept that has been proposed for the Mars Hopper; a long-lived, long-ranged mobile platform for the Martian surface. This study discusses the current state of the VATF as well as recent blow-down testing performed on a laboratory-scale prototype of the Mars Hopper. The VATF allows for the simulation of Mars ambient conditions within the pressure vessel as well as to safely perform blow-down tests through the prototype using CO2 gas; the proposed propellant for the Mars Hopper. Empirical data gathered will lead to a better understanding of CO2 behavior and will provide validation of simulation models. Additionally, the potential of the VATF to test varying propulsion system designs has been recognized. In addition to being able to simulate varying atmospheres and blow-down gases for the RTR, it can be fitted to perform high temperature hydrogen testing of fuel elements for nuclear thermal propulsion.
Date: February 1, 2013
Creator: Jerred, Nathan D.; O'Brien, Robert C.; Howe, Steven D. & O'Brien, James E.
System: The UNT Digital Library
Economical Production of Pu-238 (open access)

Economical Production of Pu-238

All space exploration missions traveling beyond Jupiter must use radioisotopic power sources for electrical power. The best isotope to power these sources is plutonium-238. The US supply of Pu-238 is almost exhausted and will be gone within the next decade. The Department of Energy has initiated a production program with a $10M allocation from NASA but the cost is estimated at over $100 M to get to production levels. The Center for Space Nuclear Research has conceived of a potentially better process to produce Pu-238 earlier and for significantly less cost. The new process will also produce dramatically less waste. Potentially, the front end costs could be provided by private industry such that the government only had to pay for the product produced. Under a NASA Phase I NIAC grant, the CSNR has evaluated the feasibility of using a low power, commercially available nuclear reactor to produce at least 1.5 kg of Pu-238 per year. The impact on the neutronics of the reactor have been assessed, the amount of Neptunium target material estimated, and the production rates calculated. In addition, the size of the post-irradiation processing facility has been established. In addition, a new method for fabricating the Pu-238 product …
Date: February 1, 2013
Creator: Howe, Steven D.; Crawford, Douglas; Navarro, Jorge & Ring, Terry
System: The UNT Digital Library
EGS rock reactions with Supercritical CO2 saturated with water and water saturated with Supercritical CO2 (open access)

EGS rock reactions with Supercritical CO2 saturated with water and water saturated with Supercritical CO2

EGS using CO2 as a working fluid will likely involve hydro-shearing low-permeability hot rock reservoirs with a water solution. After that process, the fractures will be flushed with CO2 that is maintained under supercritical conditions (> 70 bars). Much of the injected water in the main fracture will be flushed out with the initial CO2 injection; however side fractures, micro fractures, and the lower portion of the fracture will contain connate water that will interact with the rock and the injected CO2. Dissolution/precipitation reactions in the resulting scCO2/brine/rock systems have the potential to significantly alter reservoir permeability, so it is important to understand where these precipitates form and how are they related to the evolving ‘free’ connate water in the system. To examine dissolution / precipitation behavior in such systems over time, we have conducted non-stirred batch experiments in the laboratory with pure minerals, sandstone, and basalt coupons with brine solution spiked with MnCl2 and scCO2. The coupons are exposed to liquid water saturated with scCO2 and extend above the water surface allowing the upper portion of the coupons to be exposed to scCO2 saturated with water. The coupons were subsequently analyzed using SEM to determine the location of reactions …
Date: February 1, 2013
Creator: Mattson, Earl D.; McLing, Travis L.; Smith, William & Palmer, Carl
System: The UNT Digital Library
Experimental investigation of brine-CO2 flow through a natural fracture: permeability increases with concurrent dissolution/reprecipitation reactions (open access)

Experimental investigation of brine-CO2 flow through a natural fracture: permeability increases with concurrent dissolution/reprecipitation reactions

None
Date: February 1, 2013
Creator: Smith, Megan M.; Walsh, Stuart C.; McNab, Walt W. & Carroll, Susan A.
System: The UNT Digital Library
Fabrication of Cerium Oxide and Uranium Oxide Microspheres for Space Nuclear Power Applications (open access)

Fabrication of Cerium Oxide and Uranium Oxide Microspheres for Space Nuclear Power Applications

Cerium oxide and uranium oxide microspheres are being produced via an internal gelation sol-gel method to investigate alternative fabrication routes for space nuclear fuels. Depleted uranium and non-radioactive cerium are being utilized as surrogates for plutonium-238 (Pu-238) used in radioisotope thermoelectric generators and for enriched uranium required by nuclear thermal rockets. While current methods used to produce Pu-238 fuels at Los Alamos National Laboratory (LANL) involve the generation of fine powders that pose a respiratory hazard and have a propensity to contaminate glove boxes, the sol-gel route allows for the generation of oxide microsphere fuels through an aqueous route. The sol-gel method does not generate fine powders and may require fewer processing steps than the LANL method with less operator handling. High-quality cerium dioxide microspheres have been fabricated in the desired size range and equipment is being prepared to establish a uranium dioxide microsphere production capability.
Date: February 1, 2013
Creator: Katalenich, Jeffrey A.; Hartman, Michael R. & O'Brien, Robert C.
System: The UNT Digital Library
GPS Data Filtration Method for Drive Cycle Analysis Applications (open access)

GPS Data Filtration Method for Drive Cycle Analysis Applications

When employing GPS data acquisition systems to capture vehicle drive-cycle information, a number of errors often appear in the raw data samples, such as sudden signal loss, extraneous or outlying data points, speed drifting, and signal white noise, all of which limit the quality of field data for use in downstream applications. Unaddressed, these errors significantly impact the reliability of source data and limit the effectiveness of traditional drive-cycle analysis approaches and vehicle simulation software. Without reliable speed and time information, the validity of derived metrics for drive cycles, such as acceleration, power, and distance, become questionable. This study explores some of the common sources of error present in raw onboard GPS data and presents a detailed filtering process designed to correct for these issues. Test data from both light and medium/heavy duty applications are examined to illustrate the effectiveness of the proposed filtration process across the range of vehicle vocations. Graphical comparisons of raw and filtered cycles are presented, and statistical analyses are performed to determine the effects of the proposed filtration process on raw data. Finally, an evaluation of the overall benefits of data filtration on raw GPS data and present potential areas for continued research is presented.
Date: February 1, 2013
Creator: Duran, A. & Earleywine, M.
System: The UNT Digital Library
High-Efficiency Retrofit Lessons for Retail from a SuperTarget: Preprint (open access)

High-Efficiency Retrofit Lessons for Retail from a SuperTarget: Preprint

The National Renewable Energy Laboratory partnered with Target under the Commercial Building Program to design and implement a retrofit of a SuperTarget in Thornton, CO. The result was a retrofit design that predicted 37% energy savings over ASHRAE Standard 90.1-2004, and 29% compared to existing (pre-retrofit) store consumption. The largest savings came from energy efficient lighting, energy efficient cooling systems, improved refrigeration, and better control of plug loads.
Date: February 1, 2013
Creator: Langner, R.; Deru, M.; Hirsch, A. & Williams, S.
System: The UNT Digital Library
Marine Hydrokinetic Turbine Power-Take-Off Design for Optimal Performance and Low Impact on Cost-of-Energy: Preprint (open access)

Marine Hydrokinetic Turbine Power-Take-Off Design for Optimal Performance and Low Impact on Cost-of-Energy: Preprint

Marine hydrokinetic devices are becoming a popular method for generating marine renewable energy worldwide. These devices generate electricity by converting the kinetic energy of moving water, wave motion or currents, into electrical energy through the use of a power-take-off (PTO) system. Most PTO systems incorporate a mechanical or hydraulic drivetrain, power generator, and electric control/conditioning system to deliver the generated electric power to the grid at the required state. Like wind turbine applications, the PTO system must be designed for high reliability, good efficiency, and long service life with reasonable maintenance requirements, low cost, and an appropriate mechanical design for anticipated applied steady and unsteady loads. The ultimate goal of a PTO design is high efficiency and low maintenance and cost, with a low impact on the device cost-of-energy (CoE).
Date: February 1, 2013
Creator: Beam, M.; Kline, B.; Elbing, B.; Straka, W.; Fontaine, A.; Lawson, M. et al.
System: The UNT Digital Library
Microbial impacts on geothermometry temperature predictions (open access)

Microbial impacts on geothermometry temperature predictions

Conventional geothermometry approaches assume that the composition of a collected water sample originating in a deep geothermal reservoir still reflects chemical equilibration of the water with the deep reservoir rocks. However, for geothermal prospecting samples whose temperatures have dropped to <120°C, temperature predictions may be skewed by the activity of microorganisms; microbial metabolism can drastically and rapidly change the water’s chemistry. We hypothesize that knowledge of microbial impacts on exploration sample geochemistry can be used to constrain input into geothermometry models and thereby improve the reliability of reservoir temperature predictions. To evaluate this hypothesis we have chosen to focus on sulfur cycling, because of the significant changes in redox state and pH associated with sulfur chemistry. Redox and pH are critical factors in defining the mineral-fluid equilibria that form the basis of solute geothermometry approaches. Initially we are developing assays to detect the process of sulfate reduction, using knowledge of genes specific to sulfate reducing microorganisms. The assays rely on a common molecular biological technique known as quantitative polymerase chain reaction (qPCR), which allows estimation of the number of target organisms in a particular sample by enumerating genes specific to the organisms rather than actually retrieving and characterizing the organisms …
Date: February 1, 2013
Creator: Fujita, Yoshiko; Reed, David W.; Nowak, Kaitlyn R.; Thompson, Vicki S.; McLing, Travis L. & Smith, Robert W.
System: The UNT Digital Library
Multicomponent Equilibrium Models for Testing Geot (open access)

Multicomponent Equilibrium Models for Testing Geot

Geothermometry is an important tool for estimating
Date: February 1, 2013
Creator: Palmer, Carl D.; Smith, Robert W. & McLing, Travis L.
System: The UNT Digital Library
Numerical Stability and Accuracy of Temporally Coupled Multi-Physics Modules in Wind-Turbine CAE Tools (open access)

Numerical Stability and Accuracy of Temporally Coupled Multi-Physics Modules in Wind-Turbine CAE Tools

In this paper we examine the stability and accuracy of numerical algorithms for coupling time-dependent multi-physics modules relevant to computer-aided engineering (CAE) of wind turbines. This work is motivated by an in-progress major revision of FAST, the National Renewable Energy Laboratory's (NREL's) premier aero-elastic CAE simulation tool. We employ two simple examples as test systems, while algorithm descriptions are kept general. Coupled-system governing equations are framed in monolithic and partitioned representations as differential-algebraic equations. Explicit and implicit loose partition coupling is examined. In explicit coupling, partitions are advanced in time from known information. In implicit coupling, there is dependence on other-partition data at the next time step; coupling is accomplished through a predictor-corrector (PC) approach. Numerical time integration of coupled ordinary-differential equations (ODEs) is accomplished with one of three, fourth-order fixed-time-increment methods: Runge-Kutta (RK), Adams-Bashforth (AB), and Adams-Bashforth-Moulton (ABM). Through numerical experiments it is shown that explicit coupling can be dramatically less stable and less accurate than simulations performed with the monolithic system. However, PC implicit coupling restored stability and fourth-order accuracy for ABM; only second-order accuracy was achieved with RK integration. For systems without constraints, explicit time integration with AB and explicit loose coupling exhibited desired accuracy and stability.
Date: February 1, 2013
Creator: Gasmi, A.; Sprague, M. A.; Jonkman, J. M. & Jones, W. B.
System: The UNT Digital Library
The Oxygen Reduction Reaction on Nitrogen-Doped Graphene (open access)

The Oxygen Reduction Reaction on Nitrogen-Doped Graphene

None
Date: February 1, 2013
Creator: Studt, Felix
System: The UNT Digital Library
Planning For Multiple NASA Missions With Use Of Enabling Radioisotope Power (open access)

Planning For Multiple NASA Missions With Use Of Enabling Radioisotope Power

Since the early 1960’s the Department of Energy (DOE) and its predecessor agencies have provided radioisotope power systems (RPS) to NASA as an enabling technology for deep space and various planetary missions. They provide reliable power in situations where solar and/or battery power sources are either untenable or would place an undue mass burden on the mission. In the modern era of the past twenty years there has been no time that multiple missions have been considered for launching from Kennedy Space Center (KSC) during the same year. The closest proximity of missions that involved radioisotope power systems would be that of Galileo (October 1989) and Ulysses (October 1990). The closest that involved radioisotope heater units would be the small rovers Spirit and Opportunity (May and July 2003) used in the Mars Exploration Rovers (MER) mission. It can be argued that the rovers sent to Mars in 2003 were essentially a special case since they staged in the same facility and used a pair of small launch vehicles (Delta II). This paper examines constraints on the frequency of use of radioisotope power systems with regard to launching them from Kennedy Space Center using currently available launch vehicles. This knowledge may …
Date: February 1, 2013
Creator: Johnson, S.G.; Lively, K.L. & Dwight, C.C.
System: The UNT Digital Library
Preconceptual Feasibility Study to Evaluate Alternative Means to Produce Plutonium-238 (open access)

Preconceptual Feasibility Study to Evaluate Alternative Means to Produce Plutonium-238

There is currently no large-scale production of 238Pu in the United States. Feasibility studies were performed at the Idaho National Laboratory to assess the capability of developing alternative 238Pu production strategies. Initial investigations indicate potential capability to provision radioisotope-powered systems for future space exploration endeavors. For the short term production of 238Pu, sealed canisters of dilute 237Np solution in nitric acid could be irradiated in the Advanced Test Reactor (ATR). Targets in the large and medium “I” positions of the ATR were irradiated over a simulated period of 306 days and analyzed using MCNP5 and ORIGEN2.2. Approximately 0.5 kg of 238Pu could be produced annually in the ATR with purity greater than 92%. Optimization of the irradiation cycles could further increase the purity to greater than 98%. Whereas the typical purity of space batteries is between 80 to 85%, the higher purity 238Pu produced in the ATR could be blended with existing lower-purity inventory to produce useable material. Development of irradiation methods in the ATR provides the fastest alterative to restart United States 238Pu production. The analysis of 238Pu production in the ATR provides the technical basis for production using TRIGA® (Training, Research, Isotopes, General Atomics) nuclear reactors. Preliminary analyses …
Date: February 1, 2013
Creator: Bess, John D. & Everson, Matthew S.
System: The UNT Digital Library
Radiation Stability of Benzyl Tributyl Ammonium Chloride Towards Technetium-99 Extraction (open access)

Radiation Stability of Benzyl Tributyl Ammonium Chloride Towards Technetium-99 Extraction

A closed nuclear fuel cycle combining new separation technologies along with generation III and generation IV reactors is a promising way to achieve a sustainable energy supply. But it is important to keep in mind that future recycling processes of used nuclear fuel (UNF) must minimize wastes, improve partitioning process, and integrate waste considerations into processes. New separation processes are being developed worldwide to complement the actual industrialized PUREX process which selectively separates U(VI) and Pu(IV) from the raffinate. As an example, low nitric acid concentration in the aqueous phase of a UREX based process will co-extract U(VI) and Tc(VII) by tri-n-butyl phosphate (TBP). Technetium (Tc-99) is recognized to be one of the most abundant, long-lived radiotoxic isotopes in UNF (half-life, t1/2 = 2.13 × 105 years), and as such, it is targeted in UNF separation strategies for isolation and encapsulation in solid waste forms for final disposal in a nuclear waste repository. Immobilization of Tc-99 by a durable solid waste form is a challenge, and its fate in new advanced technology processes is of importance. It is essential to be able to quantify and locate 1) its occurrence in any new developed flow sheets, 2) its chemical form in …
Date: February 1, 2013
Creator: Horkley, Jared; Roman, Audrey; Campbell, Keri; Nunez, Ana & Espartero, Amparo
System: The UNT Digital Library

Response to "A critique of Abraham and Acree's correlation for deca-1,9-diene/water partition coefficients"

This article is a response to "A critique of Abraham and Acree's correlation for deca-1,9-diene/water partition coefficients," published in New Journal of Chemistry, 2013.
Date: February 1, 2013
Creator: Abraham, M. H. (Michael H.) & Acree, William E. (William Eugene)
System: The UNT Digital Library
Simulated evolution of fractures and fracture networks subject to thermal cooling: A coupled discrete element and heat conduction model (open access)

Simulated evolution of fractures and fracture networks subject to thermal cooling: A coupled discrete element and heat conduction model

Advancement of EGS requires improved prediction of fracture development and growth during reservoir stimulation and long-term operation. This, in turn, requires better understanding of the dynamics of the strongly coupled thermo-hydro-mechanical (THM) processes within fractured rocks. We have developed a physically based rock deformation and fracture propagation simulator by using a quasi-static discrete element model (DEM) to model mechanical rock deformation and fracture propagation induced by thermal stress and fluid pressure changes. We also developed a network model to simulate fluid flow and heat transport in both fractures and porous rock. In this paper, we describe results of simulations in which the DEM model and network flow & heat transport model are coupled together to provide realistic simulation of the changes of apertures and permeability of fractures and fracture networks induced by thermal cooling and fluid pressure changes within fractures. Various processes, such as Stokes flow in low velocity pores, convection-dominated heat transport in fractures, heat exchange between fluid-filled fractures and solid rock, heat conduction through low-permeability matrices and associated mechanical deformations are all incorporated into the coupled model. The effects of confining stresses, developing thermal stress and injection pressure on the permeability evolution of fracture and fracture networks are …
Date: February 1, 2013
Creator: Huang, Hai; Plummer, Mitchell & Podgorney, Robert
System: The UNT Digital Library
Third minima in thorium and uranium isotopes in the self-consistent theory (open access)

Third minima in thorium and uranium isotopes in the self-consistent theory

None
Date: February 1, 2013
Creator: McDonnell, J; Nazarewicz, W & Sheikh, J A
System: The UNT Digital Library
Tourist See Tourist Do: The Influence of Hollywood Movies and Television on Tourism Motivation and Activity Behavior (open access)

Tourist See Tourist Do: The Influence of Hollywood Movies and Television on Tourism Motivation and Activity Behavior

Article investigates the influence of Hollywood movies and television (movies/TV) on US viewer’s motivation to travel to and participate in activities featured in Hollywood movies/TV productions. Findings identified a profile of Hollywood movies/TV viewers, sources of information used to determine destination choice, and level of involvement among viewers of Hollywood movies/TV productions. Additionally, this study explored the relationships between Hollywood movies/TV productions, tourist motivations, and the propensity to participate in activities featured.
Date: February 2013
Creator: Spears, Daniel L.; Josiam, Bharath M.; Kinley, Tammy & Pookulangara, Sanjukta
System: The UNT Digital Library