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Acceptance Performance Test Guideline for Utility Scale Parabolic Trough and Other CSP Solar Thermal Systems: Preprint (open access)

Acceptance Performance Test Guideline for Utility Scale Parabolic Trough and Other CSP Solar Thermal Systems: Preprint

Prior to commercial operation, large solar systems in utility-size power plants need to pass a performance acceptance test conducted by the engineering, procurement, and construction (EPC) contractor or owners. In lieu of the present absence of ASME or other international test codes developed for this purpose, the National Renewable Energy Laboratory has undertaken the development of interim guidelines to provide recommendations for test procedures that can yield results of a high level of accuracy consistent with good engineering knowledge and practice. Progress on interim guidelines was presented at SolarPACES 2010. Significant additions and modifications were made to the guidelines since that time, resulting in a final report published by NREL in April 2011. This paper summarizes those changes, which emphasize criteria for assuring thermal equilibrium and steady state conditions within the solar field.
Date: August 1, 2011
Creator: Mehos, M. S.; Wagner, M. J. & Kearney, D. W.
System: The UNT Digital Library
Advanced Test Reactor National Scientific User Facility (open access)

Advanced Test Reactor National Scientific User Facility

The Advanced Test Reactor (ATR), at the Idaho National Laboratory (INL), is a large test reactor for providing the capability for studying the effects of intense neutron and gamma radiation on reactor materials and fuels. The ATR is a pressurized, light-water, high flux test reactor with a maximum operating power of 250 MWth. The INL also has several hot cells and other laboratories in which irradiated material can be examined to study material irradiation effects. In 2007 the US Department of Energy (DOE) designated the ATR as a National Scientific User Facility (NSUF) to facilitate greater access to the ATR and the associated INL laboratories for material testing research by a broader user community. This paper highlights the ATR NSUF research program and the associated educational initiatives.
Date: August 1, 2011
Creator: Marshall, Frances M.; Benson, Jeff & Thelen, Mary Catherine
System: The UNT Digital Library
Anomaly Detection for Resilient Control Systems Using Fuzzy-Neural Data Fusion Engine (open access)

Anomaly Detection for Resilient Control Systems Using Fuzzy-Neural Data Fusion Engine

Resilient control systems in critical infrastructures require increased cyber-security and state-awareness. One of the necessary conditions for achieving the desired high level of resiliency is timely reporting and understanding of the status and behavioral trends of the control system. This paper describes the design and development of a neural-network based data-fusion system for increased state-awareness of resilient control systems. The proposed system consists of a dedicated data-fusion engine for each component of the control system. Each data-fusion engine implements three-layered alarm system consisting of: (1) conventional threshold-based alarms, (2) anomalous behavior detector using self-organizing maps, and (3) prediction error based alarms using neural network based signal forecasting. The proposed system was integrated with a model of the Idaho National Laboratory Hytest facility, which is a testing facility for hybrid energy systems. Experimental results demonstrate that the implemented data fusion system provides timely plant performance monitoring and cyber-state reporting.
Date: August 1, 2011
Creator: Linda, Ondrej; Manic, Milos & McJunkin, Timothy R.
System: The UNT Digital Library
Banff Challenge 2 (open access)

Banff Challenge 2

Experimental particle physics collaborations constantly seek newer and better ideas for improving the sensitivity of their searches for new particles and phenomena. Statistical techniques are the last step in interpreting the results of an experiment; they are used to make discoveries (hypothesis testing), and to measure parameters (point estimation). They are also used in the first step - experiment and analysis design. Banff Challenge 2 asks participants to test their methods of discovering hidden signals in simulated datasets and of measuring the properties of these signals. The Challenge problems are described, and the performances of the submitted entries is summarized, for datasets with and without simulated signals present.
Date: August 1, 2011
Creator: Junk, Thomas R.
System: The UNT Digital Library
Beam Line Commissioning of a UV/VUV FEL at Jefferson Lab (open access)

Beam Line Commissioning of a UV/VUV FEL at Jefferson Lab

Many novel applications in photon sciences require very high brightness and/or short pulses in the vacuum ultra-violet (VUV). Jefferson Lab has commissioned a UV oscillator with high gain and has transported the third harmonic of the UV to a user lab. The experimental performance of the UV FEL is much better than simulated performance in both gain and efficiency. This success is important for efforts to push towards higher gain FELs at short wavelengths where mirrors absorb strongly. We will report on efforts to characterize the UV laser and the VUV coherent harmonics as well as designs to lase directly in the VUV wavelength range.
Date: August 1, 2011
Creator: Benson, Stephen; Blackburn, Keith; Bullard, Daniel; Clavero Perez, Cesar; Coleman, James; Dickover, Cody et al.
System: The UNT Digital Library
Collimation Studies with Hollow Electron Beams (open access)

Collimation Studies with Hollow Electron Beams

Recent experimental studies at the Fermilab Tevatron collider have shown that magnetically confined hollow electron beams can act as a new kind of collimator for high-intensity beams in storage rings. In a hollow electron beam collimator, electrons enclose the circulating beam. Their electric charge kicks halo particles transversely. If their distribution is axially symmetric, the beam core is unaffected. This device is complementary to conventional two-stage collimation systems: the electron beam can be placed arbitrarily close to the circulating beam; and particle removal is smooth, so that the device is a diffusion enhancer rather than a hard aperture limitation. The concept was tested in the Tevatron collider using a hollow electron gun installed in one of the existing electron lenses. We describe some of the technical aspects of hollow-beam scraping and the results of recent measurements.
Date: August 1, 2011
Creator: Stancari, G.; Annala, G.; Johnson, T. R.; Saewert, G. W.; Shiltsev, V.; Still, D. A. et al.
System: The UNT Digital Library
Combined CDF and D0 upper limits on $gg\to H\to W^+W^-$ and constraints on the Higgs boson mass in fourth-generation fermion models with up to 8.2 fb$^{-1}$ of data (open access)

Combined CDF and D0 upper limits on $gg\to H\to W^+W^-$ and constraints on the Higgs boson mass in fourth-generation fermion models with up to 8.2 fb$^{-1}$ of data

We combine results from searches by the CDF and D0 Collaborations for a standard model Higgs boson (H) in the processes gg {yields} H {yields} W{sup +}W{sup -} and gg {yields} H {yields} ZZ in p{bar p} collisions at the Fermilab Tevatron Collider at {radical}s = 1.96 TeV. With 8.2 fb{sup -1} of integrated luminosity analyzed at CDF and 8.1 fb{sup -1} at D0, the 95% C.L. upper limit on {sigma}(gg {yields} H) x {Beta}(H {yields} W{sup +}W{sup -}) is 1.01 pb at m{sub H} = 120 GeV, 0.40 pb at m{sub H} = 165 GeV, and 0.47 pb at m{sub H} = 200 GeV. Assuming the presence of a fourth sequential generation of fermions with large masses, we exclude at the 95% Confidence Level a standard-model-like Higgs boson with a mass between 124 and 286 GeV.
Date: August 1, 2011
Creator: Benjamin, Doug
System: The UNT Digital Library
Compression Waves and Phase Plots: Simulations (open access)

Compression Waves and Phase Plots: Simulations

Compression wave analysis started nearly 50 years ago with Fowles. Coperthwaite and Williams gave a method that helps identify simple and steady waves. We have been developing a method that gives describes the non-isentropic character of compression waves, in general. One result of that work is a simple analysis tool. Our method helps clearly identify when a compression wave is a simple wave, a steady wave (shock), and when the compression wave is in transition. This affects the analysis of compression wave experiments and the resulting extraction of the high-pressure equation of state.
Date: August 1, 2011
Creator: Orlikowski, D. & Minich, R.
System: The UNT Digital Library
Conceptual Design of a CERMET NTR Fission Core Using Multiphysics Modeling Techniques (open access)

Conceptual Design of a CERMET NTR Fission Core Using Multiphysics Modeling Techniques

An initial pre-conceptual CERMET Nuclear Thermal Propulsion reactor system is investigated within this paper. Reactor configurations are investigated where the fuel consists of 60 vol.% UO2 and 40 vol.% W where the UO2 consists of Gd2O3 concentrations of 5 and 10 mol.%.Gd2O3. The fuel configuration consisting of 5 mol.% UO2 was found to have a total mass of 2761 kg and a thrust to weight ratio of 4.10 and required a coolant channel surface area to fueled volume ratio of approximately 15.0 in order to keep the centerline temperature below 3000 K. The configuration consisting of 10 mol.% Gd2O3 required a surface area to volume ratio of approximately 12.2 to cool the reactor to a peak temperature of 3000 K and had a total mass of 3200 kg and a thrust to weight ratio of 3.54. It is not known yet what concentration of Gd2O3 is required to maintain fuel stability at 3000 K; however, both reactors offer the potential for operations at 25,000 lb, and at a specific impulse which may range from 900 to 950 seconds.
Date: August 1, 2011
Creator: Webb, Jonathan A.; Gross, Brian J. & Taitano, William T.
System: The UNT Digital Library
Developing an Integrated Model Framework for the Assessment of Sustainable Agricultural Residue Removal Limits for Bioenergy Systems (open access)

Developing an Integrated Model Framework for the Assessment of Sustainable Agricultural Residue Removal Limits for Bioenergy Systems

Agricultural residues have significant potential as a feedstock for bioenergy production, but removing these residues can have negative impacts on soil health. Models and datasets that can support decisions about sustainable agricultural residue removal are available; however, no tools currently exist capable of simultaneously addressing all environmental factors that can limit availability of residue. The VE-Suite model integration framework has been used to couple a set of environmental process models to support agricultural residue removal decisions. The RUSLE2, WEPS, and Soil Conditioning Index models have been integrated. A disparate set of databases providing the soils, climate, and management practice data required to run these models have also been integrated. The integrated system has been demonstrated for two example cases. First, an assessment using high spatial fidelity crop yield data has been run for a single farm. This analysis shows the significant variance in sustainably accessible residue across a single farm and crop year. A second example is an aggregate assessment of agricultural residues available in the state of Iowa. This implementation of the integrated systems model demonstrates the capability to run a vast range of scenarios required to represent a large geographic region.
Date: August 1, 2011
Creator: David Muth, Jr.; Abodeely, Jared; Nelson, Richard; McCorkle, Douglas; Koch, Joshua & Bryden, Kenneth
System: The UNT Digital Library
Development of Autonomous Magnetometer Rotorcraft For Wide Area Assessment (open access)

Development of Autonomous Magnetometer Rotorcraft For Wide Area Assessment

Large areas across the United States and internationally are potentially contaminated with unexploded ordinance (UXO), with some ranges encompassing tens to hundreds of thousands of acres. Technologies are needed which will allow for cost effective wide area scanning with (1) near 100% coverage and (2) near 100% detection of subsurface ordnance or features indicative of subsurface ordnance. The current approach to wide area assessment is a multi-level one, in which medium - altitude fixed wing optical imaging is used for an initial site assessment. This assessment is followed with low altitude manned helicopter based magnetometry. Subsequent to this wide area assessment targeted surface investigations are performed using either towed geophysical sensor arrays or man portable sensors. In order to be an effective tool for small UXO detection, the sensing altitude for magnetic site investigations needs to be on the order of 1 to 3 meters. These altitude requirements mean that manned helicopter surveys will generally only be feasible in large, open and relatively flat terrains. While such surveys are effective in mapping large areas relatively fast there are substantial mobilization/demobilization, staffing and equipment costs associated with these surveys, resulting in costs of approximately $100-$150/acre. In addition, due to the low …
Date: August 1, 2011
Creator: McKay, Mark D. & Anderson, Matthew O.
System: The UNT Digital Library
Effect of impedance and higher order chromaticity on the measurement of linear chromaticity (open access)

Effect of impedance and higher order chromaticity on the measurement of linear chromaticity

The combined effect of impedance and higher order chromaticity can act on the beam in a nontrivial manner which can cause a tune shift which depends on the relative momenta with respect to the 'on momentum' particle ({Delta}p/p). Experimentally, this tune shift affects the measurement of the linear chromaticity which is traditionally measured with a change of {Delta}p/p. The theory behind this effect will be derived in this paper. Computer simulations and experimental data from the Tevatron will be used to support the theory.
Date: August 1, 2011
Creator: Ranjbar, V.H.; /Tech-X, Boulder; Tan, C.Y. & /Fermilab
System: The UNT Digital Library
Effect of pH on the Water/{alpha}-Al{sub 2}O{sub 3} (1{bar 1}02) interface structure studied by sum-frequency vibrational spectroscopy (open access)

Effect of pH on the Water/{alpha}-Al{sub 2}O{sub 3} (1{bar 1}02) interface structure studied by sum-frequency vibrational spectroscopy

Sum frequency vibrational spectroscopy (SFVS) was used to study the structure of water/{alpha}- Al{sub 2}O{sub 3} (1{bar 1}02 ) interfaces at different pH values. The OH stretch spectra are dominated by interfacial water contributions at lower frequencies, and by bonded hydroxyls on the Al{sub 2}O{sub 3} surface at higher frequencies. Protonation and deprotonation of various oxide functional groups at the {alpha}-Al{sub 2}O{sub 3} surface as pH varies can be monitored quantitatively by changes of the spectrum, allowing their pK reaction values can be estimated. The point of zero charge of the interface is found to be at pH ~ 6.7.
Date: August 1, 2011
Creator: Sung, J.; Zhang, L.; Tian, C.; Shen, Y. R. & Waychunas, G. A.
System: The UNT Digital Library
Effect of process variables on the quality attributes of briquettes from wheat, oat, canola and barley (open access)

Effect of process variables on the quality attributes of briquettes from wheat, oat, canola and barley

Effect of process variables on the quality attributes of briquettes from wheat, oat, canola and barley straw Jaya Shankar Tumuluru*, L. G. Tabil, Y. Song, K. L. Iroba and V. Meda Biomass is a renewable energy source and environmentally friendly substitute for fossil fuels such as coal and petroleum products. Major limitation of biomass for successful energy application is its low bulk density, which makes it very difficult and costly to transport and handle. To overcome this limitation, biomass has to be densified. The commonly used technologies for densification of biomass are pelletization and briquetting. Briquetting offers many advantages at it can densify larger particles sizes of biomass at higher moisture contents. Briquetting is influenced by a number of feedstock and process variables such as moisture content, particle size distribution, and some operating variables such as temperature and densification pressure. In the present study, experiments were designed and conducted based on Box-Behnken design to produce briquettes using barley, wheat, canola and barley straws. A laboratory scale hydraulic briquette press was used for the present study. The experimental process variables and their levels used in the present study were pressure levels (7.5, 10, 12.5 MPa), three levels of temperature (90, 110, …
Date: August 1, 2011
Creator: Tumuluru, Jaya Shankar
System: The UNT Digital Library
Equivalence in Ventilation and Indoor Air Quality (open access)

Equivalence in Ventilation and Indoor Air Quality

We ventilate buildings to provide acceptable indoor air quality (IAQ). Ventilation standards (such as American Society of Heating, Refrigerating, and Air-Conditioning Enginners [ASHRAE] Standard 62) specify minimum ventilation rates without taking into account the impact of those rates on IAQ. Innovative ventilation management is often a desirable element of reducing energy consumption or improving IAQ or comfort. Variable ventilation is one innovative strategy. To use variable ventilation in a way that meets standards, it is necessary to have a method for determining equivalence in terms of either ventilation or indoor air quality. This study develops methods to calculate either equivalent ventilation or equivalent IAQ. We demonstrate that equivalent ventilation can be used as the basis for dynamic ventilation control, reducing peak load and infiltration of outdoor contaminants. We also show that equivalent IAQ could allow some contaminants to exceed current standards if other contaminants are more stringently controlled.
Date: August 1, 2011
Creator: Sherman, Max; Walker, Iain & Logue, Jennifer
System: The UNT Digital Library
A Framework for Analysis of Energy-Water Interdependency Problems (open access)

A Framework for Analysis of Energy-Water Interdependency Problems

The overall objective of this work is to improve the holistic value of energy development strategies by integrating management criteria for water availability, water quality, and ecosystem health into the energy system planning process. The Snake River Basin (SRB) in southern Idaho is used as a case study to show options for improving full economic utilization of aquatic resources given multiple scenarios such as changing climate, additional regulations, and increasing population. Through the incorporation of multiple management criteria, potential crosscutting solutions to energy and water issues in the SRB can be developed. The final result of this work will be a multi-criteria decision support tool - usable by policy makers and researchers alike - that will give insight into the behavior of the management criteria over time and will allow the user to experiment with a range of potential solutions. Because several basins in the arid west are dealing with similar water, energy, and ecosystem issues, the tool and conclusions will be transferable to a wide range of locations and applications. This is a very large, multi-year project to be completed in phases. This paper deals with interactions between the hydrologic system and water use at a basin level. Future …
Date: August 1, 2011
Creator: Jeffers, Robert F. & Jacobson, Jacob J.
System: The UNT Digital Library
G-NetMon: A GPU-accelerated Network Performance Monitoring System for Large Scale Scientific Collaborations (open access)

G-NetMon: A GPU-accelerated Network Performance Monitoring System for Large Scale Scientific Collaborations

At Fermilab, we have prototyped a GPU-accelerated network performance monitoring system, called G-NetMon, to support large-scale scientific collaborations. Our system exploits the data parallelism that exists within network flow data to provide fast analysis of bulk data movement between Fermilab and collaboration sites. Experiments demonstrate that our G-NetMon can rapidly detect sub-optimal bulk data movements.
Date: August 1, 2011
Creator: Wu, Wenji; DeMar, Phil; Holmgren, Don; Singh, Amitoj & Pordes, Ruth
System: The UNT Digital Library
Gas Turbine/Solar Parabolic Trough Hybrid Design Using Molten Salt Heat Transfer Fluid: Preprint (open access)

Gas Turbine/Solar Parabolic Trough Hybrid Design Using Molten Salt Heat Transfer Fluid: Preprint

Parabolic trough power plants can provide reliable power by incorporating either thermal energy storage (TES) or backup heat from fossil fuels. This paper describes a gas turbine / parabolic trough hybrid design that combines a solar contribution greater than 50% with gas heat rates that rival those of natural gas combined-cycle plants. Previous work illustrated benefits of integrating gas turbines with conventional oil heat-transfer-fluid (HTF) troughs running at 390?C. This work extends that analysis to examine the integration of gas turbines with salt-HTF troughs running at 450 degrees C and including TES. Using gas turbine waste heat to supplement the TES system provides greater operating flexibility while enhancing the efficiency of gas utilization. The analysis indicates that the hybrid plant design produces solar-derived electricity and gas-derived electricity at lower cost than either system operating alone.
Date: August 1, 2011
Creator: Turchi, C. S. & Ma, Z.
System: The UNT Digital Library
Generic CSP Performance Model for NREL's System Advisor Model: Preprint (open access)

Generic CSP Performance Model for NREL's System Advisor Model: Preprint

The suite of concentrating solar power (CSP) modeling tools in NREL's System Advisor Model (SAM) includes technology performance models for parabolic troughs, power towers, and dish-Stirling systems. Each model provides the user with unique capabilities that are catered to typical design considerations seen in each technology. Since the scope of the various models is generally limited to common plant configurations, new CSP technologies, component geometries, and subsystem combinations can be difficult to model directly in the existing SAM technology models. To overcome the limitations imposed by representative CSP technology models, NREL has developed a 'Generic Solar System' (GSS) performance model for use in SAM. This paper discusses the formulation and performance considerations included in this model and verifies the model by comparing its results with more detailed models.
Date: August 1, 2011
Creator: Wagner, M. J. & Zhu, G.
System: The UNT Digital Library
Heavy flavor baryon states at the Tevatron (open access)

Heavy flavor baryon states at the Tevatron

Precision measurements of the masses and widths of the bottom baryon resonances {Sigma}{sub b} and {Sigma}*{sub b} and charm baryons {Lambda}{sub c}(2595), {Lambda}{sub c}(2625), {Sigma}{sub c}(2455), and {Sigma}{sub c}(2520) are reported. A new measurement of {Lambda}{sub b} production is described. The studies include the first measurement of the widths and isospin mass splittings of the members of the {Sigma}{sub b} family. The charm baryons are examined through their strong decays to the {Lambda}{sub c} ground state, and measurements of their mass differences relative to the ground state, and corresponding decay widths, are reported. The data were collected by the CDF and D0 detectors for 1.96 TeV proton-antiproton collisions during Run II at the Fermilab Tevatron.
Date: August 1, 2011
Creator: Seidel, Sally
System: The UNT Digital Library
A Hierarchical Security Architecture for Cyber-Physical Systems (open access)

A Hierarchical Security Architecture for Cyber-Physical Systems

Security of control systems is becoming a pivotal concern in critical national infrastructures such as the power grid and nuclear plants. In this paper, we adopt a hierarchical viewpoint to these security issues, addressing security concerns at each level and emphasizing a holistic cross-layer philosophy for developing security solutions. We propose a bottom-up framework that establishes a model from the physical and control levels to the supervisory level, incorporating concerns from network and communication levels. We show that the game-theoretical approach can yield cross-layer security strategy solutions to the cyber-physical systems.
Date: August 1, 2011
Creator: Zhu, Quanyan & Basar, Tamer
System: The UNT Digital Library
High Power Cryogenic Targets (open access)

High Power Cryogenic Targets

The development of high power cryogenic targets for use in parity violating electron scattering has been a crucial ingredient in the success of those experiments. As we chase the precision frontier, the demands and requirements for these targets have grown accordingly. We discuss the state of the art, and describe recent developments and strategies in the design of the next generation of these targets.
Date: August 1, 2011
Creator: Smith, Gregory
System: The UNT Digital Library
High Temperature Phase Change Materials for Thermal Energy Storage Applications: Preprint (open access)

High Temperature Phase Change Materials for Thermal Energy Storage Applications: Preprint

To store thermal energy, sensible and latent heat storage materials are widely used. Latent heat thermal energy storage (TES) systems using phase change materials (PCM) are useful because of their ability to charge and discharge a large amount of heat from a small mass at constant temperature during a phase transformation. Molten salt PCM candidates for cascaded PCMs were evaluated for the temperatures near 320 degrees C, 350 degrees C, and 380 degrees C. These temperatures were selected to fill the 300 degrees C to 400 degrees C operating range typical for parabolic trough systems, that is, as one might employ in three-PCM cascaded thermal storage. Based on the results, the best candidate for temperatures near 320 degrees C was the molten salt KNO3-4.5wt%KCl. For the 350 degrees C and 380 degrees C temperatures, the evaluated molten salts are not good candidates because of the corrosiveness and the high vapor pressure of the chlorides.
Date: August 1, 2011
Creator: Gomez, J.; Glatzmaier, G. C.; Starace, A.; Turchi, C. & Ortega, J.
System: The UNT Digital Library
Impact of Aerosols on Atmospheric Attenuation Loss in Central Receiver Systems: Preprint (open access)

Impact of Aerosols on Atmospheric Attenuation Loss in Central Receiver Systems: Preprint

Atmospheric attenuation loss between the heliostat field and receiver has been recognized as a significant source of loss in Central Receiver Systems. In clear sky situations, extinction of Direct Normal Irradiance (DNI) is primarily by aerosols in the atmosphere. When aerosol loading is high close to the surface the attenuation loss between heliostat and receivers is significantly influenced by the amount of aerosols present on a particular day. This study relates measured DNI to aerosol optical depths close to the surface of the earth. The model developed in the paper uses only measured DNI to estimate the attenuation between heliostat and receiver in a central receiver system. The requirement that only a DNI measurement is available potentially makes the model a candidate for widespread use.
Date: August 1, 2011
Creator: Sengupta, M. & Wagner, M. J.
System: The UNT Digital Library