Characteristics of Short Wavelength Compressional Alfven Eigenmodes (open access)

Characteristics of Short Wavelength Compressional Alfven Eigenmodes

Most Alfvenic activity in the frequency range between Toroidal Alfven Eigenmodes and roughly one half of the ion cyclotron frequency on NSTX [M. Ono, et al., Nucl. Fusion 40 (2000) 557], that is, approximately 0.3 MHz up to ≈ 1.2 MHz, are modes propagating counter to the neutral beam ions. These have been modeled as Compressional and Global Alfven Eigenmodes (CAE and GAE) and are excited through a Doppler-shifted cyclotron resonance with the beam ions. There is also a class of co-propagating modes at higher frequency than the counter-propagating CAE and GAE. These modes have been identified as CAE, and are seen mostly in the company of a low frequency, n=1 kink-like mode. In this paper we present measurements of the spectrum of these high frequency CAE (hfCAE), and their mode structure. We compare those measurements to a simple model of CAE and present evidence of a curious non-linear coupling of the hfCAE and the low frequency kink-like mode.
Date: December 19, 2012
Creator: Fredrickson, E. D.; Podesta, M.; Bortolon, A.; Crocker, N. A.; Gerhardt, S. P.; Bell, R. E. et al.
Object Type: Report
System: The UNT Digital Library
Concept Development for Astrophysically Relevant Turbulence on NIF (open access)

Concept Development for Astrophysically Relevant Turbulence on NIF

None
Date: December 19, 2012
Creator: Drake, R P
Object Type: Report
System: The UNT Digital Library
Engineered Trench #3 Infiltration Estimates (open access)

Engineered Trench #3 Infiltration Estimates

This report documents the appropriate ET#3 infiltration rates to utilize as part of the ET#3 Special Analysis (SA).
Date: December 19, 2012
Creator: Phifer, M. A.
Object Type: Report
System: The UNT Digital Library
Fundamental Studies of Irradiation-Induced Defect Formation and Fission Product Dynamics in Oxide Fuels (open access)

Fundamental Studies of Irradiation-Induced Defect Formation and Fission Product Dynamics in Oxide Fuels

The objective of this research program is to address major nuclear fuels performance issues for the design and use of oxide-type fuels in the current and advanced nuclear reactor applications. Fuel performance is a major issue for extending fuel burn-up which has the added advantage of reducing the used fuel waste stream. It will also be a significant issue with respect to developing advanced fuel cycle processes where it may be possible to incorporate minor actinides in various fuel forms so that they can be 'burned' rather than join the used fuel waste stream. The potential to fission or transmute minor actinides and certain long-lived fission product isotopes would transform the high level waste storage strategy by removing the need to consider fuel storage on the millennium time scale.
Date: December 19, 2012
Creator: Stubbins, James
Object Type: Report
System: The UNT Digital Library
Observation and Simulation of Long-Period Ground Motions In the Persian/Arabian Gulf From Earthquakes in Zagros Thrust Belt (open access)

Observation and Simulation of Long-Period Ground Motions In the Persian/Arabian Gulf From Earthquakes in Zagros Thrust Belt

None
Date: December 19, 2012
Creator: Pitarka, Arben; Pasyanos, Michael E.; Mellors, Robert J. & Rodgers, Arthur J.
Object Type: Report
System: The UNT Digital Library
Quantifying advective and nonstationary effects on eddy fluxes in the AmeriFlux network (open access)

Quantifying advective and nonstationary effects on eddy fluxes in the AmeriFlux network

Our goal was to study the flows within and above of a forested area and assess the degree to which horizontal subcanopy motions transport significant amounts of CO2. This process can explain why ecosystem respiration appears to be underestimated on calm nights. It is essential to understand the physical and biological mechanisms that determine relevant processes that occur on these ‘suspect’ nights.
Date: December 19, 2012
Creator: Fitzjarrald, David R.
Object Type: Report
System: The UNT Digital Library
Saltstone 3QCY12 TCLP Results (open access)

Saltstone 3QCY12 TCLP Results

A Saltstone waste form was prepared in the Savannah River National Laboratory (SRNL) from a Tank 50H sample and Z-Area premix material for the third quarter of calendar year 2012 (3QCY12). After a 34 day cure, samples of the saltstone were collected, and the waste form was shown to meet the South Carolina Hazardous Waste Management Regulations (SCHWMR) R.61-79.261.24 and R.61-79.268.48(a) requirements for a nonhazardous waste form with respect to RCRA metals and underlying hazardous constituents. These analyses met all quality assurance specifications of USEPA SW-846.
Date: December 19, 2012
Creator: Eibling, R. E.
Object Type: Report
System: The UNT Digital Library
Tank 26F-2F Evaporator Study (open access)

Tank 26F-2F Evaporator Study

Tank 26F supernate sample was sent by Savannah River Remediation to Savannah River National Laboratory for evaporation test to help understand the underlying cause of the recent gravity drain line (GDL) pluggage during operation of the 2F Evaporator system. The supernate sample was characterized prior to the evaporation test. The evaporation test involved boiling the supernate in an open beaker until the density of the concentrate (evaporation product) was between 1.4 to 1.5 g/mL. It was followed by filtering and washing of the precipitated solids with deionized water. The concentrate supernate (or concentrate filtrate), the damp unwashed precipitated solids, and the wash filtrates were characterized. All the precipitated solids dissolved during water washing. A semi-quantitative X-ray diffraction (XRD) analysis on the unwashed precipitated solids revealed their composition. All the compounds with the exception of silica (silicon oxide) are known to be readily soluble in water. Hence, their dissolution during water washing is not unexpected. Even though silica is a sparingly water-soluble compound, its dissolution is also not surprising. This stems from its small fraction in the solids as a whole and also its relative freshness. Assuming similar supernate characteristics, flushing the GDL with water (preferably warm) should facilitate dissolution and …
Date: December 19, 2012
Creator: Adu-Wusu, K.
Object Type: Report
System: The UNT Digital Library
Bonneville Project: CFD of the Spillway Tailrace (open access)

Bonneville Project: CFD of the Spillway Tailrace

US Army Corps of Engineers, Portland District (CENWP) operates the Bonneville Lock and Dam Project on the Columbia River. High spill flows that occurred during 2011 moved a large volume of rock from downstream of the spillway apron to the stilling basin and apron. Although 400 cubic yards of rocks were removed from the stilling basin, there are still large volumes of rock downstream of the apron that could, under certain flow conditions, move upstream into the stilling basin. CENWP is investigating operational changes that could be implemented to minimize future movement of rock into the stilling basin. A key analysis tool to develop these operational changes is a computational fluid dynamics (CFD) model of the spillway. A free-surface CFD model of the Bonneville spillway tailrace was developed and applied for four flow scenarios. These scenarios looked at the impact of flow volume and flow distribution on tailrace hydraulics. The simulation results showed that areas of upstream flow existed near the river bed downstream of the apron, on the apron, and within the stilling basin for all flows. For spill flows of 300 kcfs, the cross-stream and downstream extent of the recirculation zones along Cascade and Bradford Island was very …
Date: November 19, 2012
Creator: Rakowski, Cynthia L.; Serkowski, John A.; Richmond, Marshall C. & Romero Gomez, Pedro DJ
Object Type: Report
System: The UNT Digital Library
The Cornell-SLAC Pixel Array Detector at LCLS (open access)

The Cornell-SLAC Pixel Array Detector at LCLS

None
Date: November 19, 2012
Creator: Hart, P.; Boutet, S.; Carini, G.; Dragone, A.; Duda, B.; Freytag, D. et al.
Object Type: Article
System: The UNT Digital Library
Final Work Plan: ISCR Pilot Test at Montgomery City, Missouri. (open access)

Final Work Plan: ISCR Pilot Test at Montgomery City, Missouri.

None
Date: November 19, 2012
Creator: LaFreniere, L. M.
Object Type: Report
System: The UNT Digital Library
Heavy-ion-induced modification of structural and mechanical properties of carbon-nanotube aerogels (open access)

Heavy-ion-induced modification of structural and mechanical properties of carbon-nanotube aerogels

None
Date: November 19, 2012
Creator: Charnvanichborikarn, S; Shin, S J; Worsley, M A & Kucheyev, S O
Object Type: Article
System: The UNT Digital Library
Investigations of Possible Low-Level Temperature and Moisture Anomalies During the AMIE Field Campaign on Manus Island (open access)

Investigations of Possible Low-Level Temperature and Moisture Anomalies During the AMIE Field Campaign on Manus Island

This document discusses results stemming from the investigation of near-surface temperature and moisture “oddities” that were brought to light as part of the Atmospheric Radiation Measurement (ARM) Madden-Julian Oscillation (MJO) Investigation Experiment (AMIE), Dynamics of the Madden-Julian Oscillation (DYNAMO), and Cooperative Indian Ocean experiment on intraseasonal variability in the Year 2011 (CINDY2011) campaigns.
Date: November 19, 2012
Creator: Long, C. N. & Holdridge, D. J.
Object Type: Report
System: The UNT Digital Library
Enhanced optical absorption due to symmetry breaking in TiO_{2(1-x)} S_{2x} alloys (open access)

Enhanced optical absorption due to symmetry breaking in TiO_{2(1-x)} S_{2x} alloys

None
Date: October 19, 2012
Creator: Schleife, A; Rinke, P; Bechstedt, F & de Walle, C
Object Type: Article
System: The UNT Digital Library
Evaluation Of The Integrated Solubility Model, A Graded Approach For Predicting Phase Distribution In Hanford Tank Waste (open access)

Evaluation Of The Integrated Solubility Model, A Graded Approach For Predicting Phase Distribution In Hanford Tank Waste

The mission of the DOE River Protection Project (RPP) is to store, retrieve, treat and dispose of Hanford's tank waste. Waste is retrieved from the underground tanks and delivered to the Waste Treatment and Immobilization Plant (WTP). Waste is processed through a pretreatment facility where it is separated into low activity waste (LAW), which is primarily liquid, and high level waste (HLW), which is primarily solid. The LAW and HLW are sent to two different vitrification facilities and glass canisters are then disposed of onsite (for LAW) or shipped off-site (for HLW). The RPP mission is modeled by the Hanford Tank Waste Operations Simulator (HTWOS), a dynamic flowsheet simulator and mass balance model that is used for mission analysis and strategic planning. The integrated solubility model (ISM) was developed to improve the chemistry basis in HTWOS and better predict the outcome of the RPP mission. The ISM uses a graded approach to focus on the components that have the greatest impact to the mission while building the infrastructure for continued future improvement and expansion. Components in the ISM are grouped depending upon their relative solubility and impact to the RPP mission. The solubility of each group of components is characterized …
Date: October 19, 2012
Creator: Pierson, Kayla L.; Belsher, Jeremy D. & Seniow, Kendra R.
Object Type: Article
System: The UNT Digital Library
Fast Pyrolysis Oil Stabilization: An Integrated Catalytic and Membrane Approach for Improved Bio-oils (open access)

Fast Pyrolysis Oil Stabilization: An Integrated Catalytic and Membrane Approach for Improved Bio-oils

This University of Massachusetts, Amherst project, "Fast Pyrolysis Oil Stabilization: An Integrated Catalytic and Membrane Approach for Improved Bio-oils" started on 1st February 2009 and finished on August 31st 2011. The project consisted following tasks: Task 1.0: Char Removal by Membrane Separation Technology The presence of char particles in the bio-oil causes problems in storage and end-use. Currently there is no well-established technology to remove char particles less than 10 micron in size. This study focused on the application of a liquid-phase microfiltration process to remove char particles from bio-oil down to slightly sub-micron levels. Tubular ceramic membranes of nominal pore sizes 0.5 and 0.8 µm were employed to carry out the microfiltration, which was conducted in the cross-flow mode at temperatures ranging from 38 to 45 C and at three different trans-membrane pressures varying from 1 to 3 bars. The results demonstrated the removal of the major quantity of char particles with a significant reduction in overall ash content of the bio-oil. The results clearly showed that the cake formation mechanism of fouling is predominant in this process. Task 2.0 Acid Removal by Membrane Separation Technology The feasibility of removing small organic acids from the aqueous fraction of fast …
Date: October 19, 2012
Creator: \Huber, George W.; Upadhye, Aniruddha A.; Ford, David M.; Bhatia, Surita R. & Badger, Phillip C.
Object Type: Report
System: The UNT Digital Library
Incorporation of NREL Solar Advisor Model Photovoltaic Capabilities with GridLAB-D (open access)

Incorporation of NREL Solar Advisor Model Photovoltaic Capabilities with GridLAB-D

This report provides a summary of the work updating the photovoltaic model inside GridLAB-D. The National Renewable Energy Laboratory Solar Advisor Model (SAM) was utilized as a basis for algorithms and validation of the new implementation. Subsequent testing revealed that the two implementations are nearly identical in both solar impacts and power output levels. This synergized model aides the system-level impact studies of GridLAB-D, but also allows more specific details of a particular site to be explored via the SAM software.
Date: October 19, 2012
Creator: Tuffner, Francis K.; Hammerstrom, Janelle L. & Singh, Ruchi
Object Type: Report
System: The UNT Digital Library
Quantitative Tools for Dissection of Hydrogen-Producing Metabolic Networks-Final Report (open access)

Quantitative Tools for Dissection of Hydrogen-Producing Metabolic Networks-Final Report

During this project we have pioneered the development of integrated experimental-computational technologies for the quantitative dissection of metabolism in hydrogen and biofuel producing microorganisms (i.e. C. acetobutylicum and various cyanobacteria species). The application of these new methodologies resulted in many significant advances in the understanding of the metabolic networks and metabolism of these organisms, and has provided new strategies to enhance their hydrogen or biofuel producing capabilities. As an example, using mass spectrometry, isotope tracers, and quantitative flux-modeling we mapped the metabolic network structure in C. acetobutylicum. This resulted in a comprehensive and quantitative understanding of central carbon metabolism that could not have been obtained using genomic data alone. We discovered that biofuel production in this bacterium, which only occurs during stationary phase, requires a global remodeling of central metabolism (involving large changes in metabolite concentrations and fluxes) that has the effect of redirecting resources (carbon and reducing power) from biomass production into solvent production. This new holistic, quantitative understanding of metabolism is now being used as the basis for metabolic engineering strategies to improve solvent production in this bacterium. In another example, making use of newly developed technologies for monitoring hydrogen and NAD(P)H levels in vivo, we dissected the …
Date: October 19, 2012
Creator: Rabinowitz, Joshua D.; Dismukes, G.Charles.; Rabitz, Herschel A. & Amador-Noguez, Daniel
Object Type: Report
System: The UNT Digital Library
Radioactive Waste Conditioning, Immobilisation, And Encapsulation Processes And Technologies: Overview And Advances (Chapter 7) (open access)

Radioactive Waste Conditioning, Immobilisation, And Encapsulation Processes And Technologies: Overview And Advances (Chapter 7)

The main immobilization technologies that are available commercially and have been demonstrated to be viable are cementation, bituminization, and vitrification. Vitrification is currently the most widely used technology for the treatment of high level radioactive wastes (HLW) throughout the world. Most of the nations that have generated HLW are immobilizing in either alkali borosilicate glass or alkali aluminophosphate glass. The exact compositions of nuclear waste glasses are tailored for easy preparation and melting, avoidance of glass-in-glass phase separation, avoidance of uncontrolled crystallization, and acceptable chemical durability, e.g., leach resistance. Glass has also been used to stabilize a variety of low level wastes (LLW) and mixed (radioactive and hazardous) low level wastes (MLLW) from other sources such as fuel rod cladding/decladding processes, chemical separations, radioactive sources, radioactive mill tailings, contaminated soils, medical research applications, and other commercial processes. The sources of radioactive waste generation are captured in other chapters in this book regarding the individual practices in various countries (legacy wastes, currently generated wastes, and future waste generation). Future waste generation is primarily driven by interest in sources of clean energy and this has led to an increased interest in advanced nuclear power production. The development of advanced wasteforms is a …
Date: October 19, 2012
Creator: Jantzen, Carol M.; Lee, William E. & Ojovan, Michael I.
Object Type: Book
System: The UNT Digital Library
Accelerated Corrosion of Stainless Steel in Thiocyanate-Containing Solutions (open access)

Accelerated Corrosion of Stainless Steel in Thiocyanate-Containing Solutions

It is known that reduced sulfur compounds (such as thiocyanate and thiosulfate) can accelerate active corrosion of austenitic stainless steel in acid solutions, but before we started this project the mechanism of acceleration was largely unclear. This work combined electrochemical measurements and analysis using scanning electron microscopy (SEM) and X-ray photo-electron spectroscopy (XPS), which provided a comprehensive understanding of the catalytic effect of reduced sulfur species on the active corrosion of stainless steel. Both the behavior of the pure elements and the steel were studied and the work focused on the interaction between the pure elements of the steel, which is the least understood area. Upon completion of this work, several aspects are now much clearer. The main results from this work can be summarized as follows: The presence of low concentrations (around 0.1 mM) of thiocyanate or tetrathionate in dilute sulfuric acid greatly accelerates the anodic dissolution of chromium and nickel, but has an even stronger effect on stainless steels (iron-chromium-nickel alloys). Electrochemical measurements and surface analyses are in agreement with the suggestion that accelerated dissolution really results from suppressed passivation. Even well below the passivation potential, the electrochemical signature of passivation is evident in the electrode impedance; the …
Date: September 19, 2012
Creator: Pistorius, P. Chris & Li, Wen
Object Type: Report
System: The UNT Digital Library
ARM Standards Policy Committee Report (open access)

ARM Standards Policy Committee Report

Data and metadata standards promote the consistent recording of information and are necessary to ensure the stability and high quality of Atmospheric Radiation Measurement (ARM) Climate Research Facility data products for scientific users. Standards also enable automated routines to be developed to examine data, which leads to more efficient operations and assessment of data quality. Although ARM Infrastructure agrees on the utility of data and metadata standards, there is significant confusion over the existing standards and the process for allowing the release of new data products with exceptions to the standards. The ARM Standards Policy Committee was initiated in March 2012 to develop a set of policies and best practices for ARM data and metadata standards.
Date: September 19, 2012
Creator: Cialella, A; Jensen, M; Koontz, A; McFarlane, S; McCoy, R; Monroe, J et al.
Object Type: Report
System: The UNT Digital Library
Atmospheric PSF Interpolation for Weak Lensing in Short Exposure Imaging Data (open access)

Atmospheric PSF Interpolation for Weak Lensing in Short Exposure Imaging Data

A main science goal for the Large Synoptic Survey Telescope (LSST) is to measure the cosmic shear signal from weak lensing to extreme accuracy. One difficulty, however, is that with the short exposure time ({approx_equal}15 seconds) proposed, the spatial variation of the Point Spread Function (PSF) shapes may be dominated by the atmosphere, in addition to optics errors. While optics errors mainly cause the PSF to vary on angular scales similar or larger than a single CCD sensor, the atmosphere generates stochastic structures on a wide range of angular scales. It thus becomes a challenge to infer the multi-scale, complex atmospheric PSF patterns by interpolating the sparsely sampled stars in the field. In this paper we present a new method, psfent, for interpolating the PSF shape parameters, based on reconstructing underlying shape parameter maps with a multi-scale maximum entropy algorithm. We demonstrate, using images from the LSST Photon Simulator, the performance of our approach relative to a 5th-order polynomial fit (representing the current standard) and a simple boxcar smoothing technique. Quantitatively, psfent predicts more accurate PSF models in all scenarios and the residual PSF errors are spatially less correlated. This improvement in PSF interpolation leads to a factor of 3.5 …
Date: September 19, 2012
Creator: Chang, C.; Marshall, P.J.; Jernigan, J.G.; Peterson, J.R.; Kahn, S.M.; Gull, S.F. et al.
Object Type: Article
System: The UNT Digital Library
Energy Saving Melting and Revert Reduction Technology: Aging of Graphitic Cast Irons and Machinability (open access)

Energy Saving Melting and Revert Reduction Technology: Aging of Graphitic Cast Irons and Machinability

The objective of this task was to determine whether ductile iron and compacted graphite iron exhibit age strengthening to a statistically significant extent. Further, this effort identified the mechanism by which gray iron age strengthens and the mechanism by which age-strengthening improves the machinability of gray cast iron. These results were then used to determine whether age strengthening improves the machinability of ductile iron and compacted graphite iron alloys in order to develop a predictive model of alloy factor effects on age strengthening. The results of this work will lead to reduced section sizes, and corresponding weight and energy savings. Improved machinability will reduce scrap and enhance casting marketability. Technical Conclusions: • Age strengthening was demonstrated to occur in gray iron ductile iron and compacted graphite iron. • Machinability was demonstrated to be improved by age strengthening when free ferrite was present in the microstructure, but not in a fully pearlitic microstructure. • Age strengthening only occurs when there is residual nitrogen in solid solution in the Ferrite, whether the ferrite is free ferrite or the ferrite lamellae within pearlite. • Age strengthening can be accelerated by Mn at about 0.5% in excess of the Mn/S balance Estimated energy savings …
Date: September 19, 2012
Creator: Richards, Von L.
Object Type: Report
System: The UNT Digital Library
Final Report on the Development of an Improved Cloud Microphysical Product for Model and Remote Sensing Evaluation using RACORO Observations (open access)

Final Report on the Development of an Improved Cloud Microphysical Product for Model and Remote Sensing Evaluation using RACORO Observations

We proposed to analyze data collected during the Routine Aerial Facilities (AAF) Clouds with Low Optical Water Depths (CLOWD) Optical Radiative Observations (RACORO) in order to develop an integrated product of cloud microphysical properties (number concentration of drops in different size bins, total liquid drop concentration integrated over all bin sizes, liquid water content LWC, extinction of liquid clouds bw, effective radius of water drops re, and radar reflectivity factor) that could be used to evaluate large-eddy simulations (LES), general circulation models (GCMs) and ground-based remote sensing retrievals, and to develop cloud parameterizations with the end goal of improving the modeling of cloud processes and properties and their impact on atmospheric radiation. We have completed the development of this microphysical database and have submitted it to ARM for consideration of its inclusion on the ARM database as a PI product. This report describes the development of this database, and also describes research that has been conducted on cloud-aerosol interactions using the data obtained during RACORO. A list of conference proceedings and publications is also included.
Date: September 19, 2012
Creator: McFarquhar, Greg
Object Type: Report
System: The UNT Digital Library