Reaching for Peak Performance in Existing Homes -- A Cold Climate Study With Synergy Construction (open access)

Reaching for Peak Performance in Existing Homes -- A Cold Climate Study With Synergy Construction

Two test homes located in Millbury and Somerville, MA are examined with the goal of providing case studies that could be applied to other similar New England homes. The retrofit process for the enclosure and mechanical systems are examined in detail and the decision-making process is discussed.
Date: December 1, 2011
Creator: Gates, C. & Osser, R.
Object Type: Report
System: The UNT Digital Library
Developing a Cost Model and Methodology to Estimate Capital Costs for Thermal Energy Storage (open access)

Developing a Cost Model and Methodology to Estimate Capital Costs for Thermal Energy Storage

This report provides an update on the previous cost model for thermal energy storage (TES) systems. The update allows NREL to estimate the costs of such systems that are compatible with the higher operating temperatures associated with advanced power cycles. The goal of the Department of Energy (DOE) Solar Energy Technology Program is to develop solar technologies that can make a significant contribution to the United States domestic energy supply. The recent DOE SunShot Initiative sets a very aggressive cost goal to reach a Levelized Cost of Energy (LCOE) of 6 cents/kWh by 2020 with no incentives or credits for all solar-to-electricity technologies.1 As this goal is reached, the share of utility power generation that is provided by renewable energy sources is expected to increase dramatically. Because Concentrating Solar Power (CSP) is currently the only renewable technology that is capable of integrating cost-effective energy storage, it is positioned to play a key role in providing renewable, dispatchable power to utilities as the share of power generation from renewable sources increases. Because of this role, future CSP plants will likely have as much as 15 hours of Thermal Energy Storage (TES) included in their design and operation. As such, the cost …
Date: December 1, 2011
Creator: Glatzmaier, G.
Object Type: Report
System: The UNT Digital Library
Toward TW-Level, Hard X-Ray Pulses at LCLS (open access)

Toward TW-Level, Hard X-Ray Pulses at LCLS

Coherent diffraction imaging of complex molecules such as proteins requires a large number (e.g., {approx} 10{sup 13}/pulse) of hard X-ray photons within a time scale of {approx} 10 fs or less. This corresponds to a peak power of {approx} 1 TW, much larger than that currently generated by LCLS or other proposed X-ray free electron lasers (FELs). We study the feasibility of producing such pulses using a LCLS-like, low charge electron beam, as will be possible in the LCLS-II upgrade project, employing a configuration beginning with a SASE amplifier, followed by a 'self-seeding' crystal monochromator, and finishing with a long tapered undulator. Our results suggest that TW-level output power at 8.3 keV is possible from a total undulator system length around 200 m. In addition power levels larger than 100 GW are generated at the third harmonic. We present a tapering strategy that extends the original 'resonant particle' formalism by optimizing the transport lattice to maximize optical guiding and enhance net energy extraction. We discuss the transverse and longitudinal coherence properties of the output radiation pulse and the expected output pulse energy sensitivity, both to taper errors and to power fluctuations on the monochromatized SASE seed.
Date: December 13, 2011
Creator: Fawley, W. M.; Frisch, J.; Huang, Z.; Jiao, Y.; Nuhn, H. D.; Pellegrini, C. et al.
Object Type: Article
System: The UNT Digital Library
Reference Inflow Characterization for River Resource Reference Model (RM2) (open access)

Reference Inflow Characterization for River Resource Reference Model (RM2)

Sandia National Laboratory (SNL) is leading an effort to develop reference models for marine and hydrokinetic technologies and wave and current energy resources. This effort will allow the refinement of technology design tools, accurate estimates of a baseline levelized cost of energy (LCoE), and the identification of the main cost drivers that need to be addressed to achieve a competitive LCoE. As part of this effort, Oak Ridge National Laboratory was charged with examining and reporting reference river inflow characteristics for reference model 2 (RM2). Published turbulent flow data from large rivers, a water supply canal and laboratory flumes, are reviewed to determine the range of velocities, turbulence intensities and turbulent stresses acting on hydrokinetic technologies, and also to evaluate the validity of classical models that describe the depth variation of the time-mean velocity and turbulent normal Reynolds stresses. The classical models are found to generally perform well in describing river inflow characteristics. A potential challenge in river inflow characterization, however, is the high variability of depth and flow over the design life of a hydrokinetic device. This variation can have significant effects on the inflow mean velocity and turbulence intensity experienced by stationary and bottom mounted hydrokinetic energy conversion …
Date: December 1, 2011
Creator: Neary, Vincent S.
Object Type: Report
System: The UNT Digital Library
Financing Solar PV at Government Sites with PPAs and Public Debt (Brochure) (open access)

Financing Solar PV at Government Sites with PPAs and Public Debt (Brochure)

Historically, state and local governmental agencies have employed one of two models to deploy solar photovoltaic (PV) projects: (1) self-ownership (financed through a variety of means) or (2) third-party ownership through a power purchase agreement (PPA). Morris County, New Jersey, administrators recently pioneered a way to combine many of the benefits of self-ownership and third-party PPAs through a bond-PPA hybrid, frequently referred to as the Morris Model. At the request of the Department of Energy?s Solar Market Transformation group, NREL examined the hybrid model. This fact sheet describes how the hybrid model works, assesses the model?s relative advantages and challenges as compared to self-ownership and the third-party PPA model, provides a quick guide to project implementation, and assesses the replicability of the model in other jurisdictions across the United States.
Date: December 1, 2011
Creator: unknown
Object Type: Report
System: The UNT Digital Library
INTEGRATED DM 1200 MELTER TESTING OF HLW C-106/AY-102 COMPOSITION USING BUBBLERS VSL-03R3800-1 REV 0 9/15/03 (open access)

INTEGRATED DM 1200 MELTER TESTING OF HLW C-106/AY-102 COMPOSITION USING BUBBLERS VSL-03R3800-1 REV 0 9/15/03

This report documents melter and off-gas performance results obtained on the DM1200 HLW Pilot Melter during processing of simulated HLW C-106/AY-102 feed. The principal objectives of the DM1200 melter testing were to determine the achievable glass production rates for simulated HLW C-106/AY-102 feed; determine the effect of bubbling rate on production rate; characterize melter off-gas emissions; characterize the performance of the prototypical off-gas system components as well as their integrated performance; characterize the feed, glass product, and off-gas effluents; and to perform pre- and post test inspections of system components.
Date: December 29, 2011
Creator: AA, KRUGER; KS, MATLACK; W, GONG; T, BARDAKCI; NA, D'ANGELO; WK, KOT et al.
Object Type: Report
System: The UNT Digital Library
A Hierarchical Control Architecture for a PEBB-Based ILC Marx Modulator (open access)

A Hierarchical Control Architecture for a PEBB-Based ILC Marx Modulator

The idea of building power conversion systems around Power Electronic Building Blocks (PEBBs) was initiated by the U.S. Office of Naval Research in the mid 1990s. A PEBB-based design approach is advantageous in terms of power density, modularity, reliability, and serviceability. It is obvious that this approach has much appeal for pulsed power conversion including the International Linear Collider (ILC) klystron modulator application. A hierarchical control architecture has the inherent capability to support the integration of PEBBs. This has already been successfully demonstrated in a number of industrial applications in the recent past. This paper outlines the underlying concepts of a hierarchical control architecture for a PEBB-based Marx-topology ILC klystron modulator. The control in PEBB-based power conversion systems can be functionally partitioned into (three) hierarchical layers; system layer, application layer, and PEBB layer. This has been adopted here. Based on such a hierarchical partition, the interfaces are clearly identified and defined and, consequently, are easily characterised. A conceptual design of the hardware manager, executing low-level hardware oriented tasks, is detailed. In addition, the idea of prognostics is briefly discussed.
Date: December 15, 2011
Creator: Macken, K.; Burkhart, C.; Larsen, R.; Nguyen, M. N. & Olsen, J.
Object Type: Article
System: The UNT Digital Library
Supply Chain Based Solution to Prevent Fuel Tax Evasion: Proof of Concept Final Report (open access)

Supply Chain Based Solution to Prevent Fuel Tax Evasion: Proof of Concept Final Report

The goal of this research was to provide a proof-of-concept (POC) system for preventing non-taxable (non-highway diesel use) or low-taxable (jet fuel) petrochemical products from being blended with taxable fuel products and preventing taxable fuel products from cross-jurisdiction evasion. The research worked to fill the need to validate the legitimacy of individual loads, offloads, and movements by integrating and validating, on a near-real-time basis, information from global positioning system (GPS), valve sensors, level sensors, and fuel-marker sensors.
Date: December 1, 2011
Creator: Capps, Gary J.; Lascurain, Mary Beth; Franzese, Oscar; Earl, Dennis Duncan; West, David L.; McIntyre, Timothy J. et al.
Object Type: Report
System: The UNT Digital Library
Membranes and surfaces nano-engineered for pathogen capture and destruction. (open access)

Membranes and surfaces nano-engineered for pathogen capture and destruction.

None
Date: December 1, 2011
Creator: Nyman, May Devan & Stewart, Thomas Austin
Object Type: Report
System: The UNT Digital Library
Reducing Data Center Loads for a Large-Scale, Low-Energy Office Building: NREL's Research Support Facility (Book) (open access)

Reducing Data Center Loads for a Large-Scale, Low-Energy Office Building: NREL's Research Support Facility (Book)

This publication detailing the design, implementation strategies, and continuous performance monitoring of NREL's Research Support Facility data center. Data centers are energy-intensive spaces that facilitate the transmission, receipt, processing, and storage of digital data. These spaces require redundancies in power and storage, as well as infrastructure, to cool computing equipment and manage the resulting waste heat (Tschudi, Xu, Sartor, and Stein, 2003). Data center spaces can consume more than 100 times the energy of standard office spaces (VanGeet 2011). The U.S. Environmental Protection Agency (EPA) reported that data centers used 61 billion kilowatt-hours (kWh) in 2006, which was 1.5% of the total electricity consumption in the U.S. (U.S. EPA, 2007). Worldwide, data centers now consume more energy annually than Sweden (New York Times, 2009). Given their high energy consumption and conventional operation practices, there is a potential for huge energy savings in data centers. The National Renewable Energy Laboratory (NREL) is world renowned for its commitment to green building construction. In June 2010, the laboratory finished construction of a 220,000-square-foot (ft{sup 2}), LEED Platinum, Research Support Facility (RSF), which included a 1,900-ft{sup 2} data center. The RSF will expand to 360,000 ft{sup 2} with the opening of an additional wing …
Date: December 1, 2011
Creator: Sheppy, M.; Lobato, C.; Van Geet, O.; Pless, S.; Donovan, K. & Powers, C.
Object Type: Report
System: The UNT Digital Library
Search for 14.4-KeV Solar Axions Emitted in the M1-Transition of Fe-57 Nuclei with CAST (open access)

Search for 14.4-KeV Solar Axions Emitted in the M1-Transition of Fe-57 Nuclei with CAST

We have searched for 14.4 keV solar axions or more general axion-like particles (ALPs), that may be emitted in the M1 nuclear transition of 57Fe, by using the axion-to-photon conversion in the CERN Axion Solar Telescope (CAST) with evacuated magnet bores (Phase I). From the absence of excess of the monoenergetic X-rays when the magnet was pointing to the Sun, we set model-independent constraints on the coupling constants of pseudoscalar particles that couple to two photons and to a nucleon g{sub ay}|-1.19g{sub aN}{sup 0}+g{sub aN}{sup 3}| < 1.36 x 10{sup -16} GeV{sup -1} for ma < 0.03 eV at the 95% confidence level.
Date: December 2, 2011
Creator: Andriamonje, S.; Aune, S.; Autiero, D.; Barth, K.; Belov, A.; Beltran, B. et al.
Object Type: Article
System: The UNT Digital Library
National 2010-2011 Survey of E85: CRC Project E-85-2 (open access)

National 2010-2011 Survey of E85: CRC Project E-85-2

This study examined the quality of E85 fuel around the country in each of the three volatility classes identified in ASTM D5798-10. Samples were collected from pumps in 21 states between July 2010 and May 2011, with almost 40 samples collected in each class. Parameters tested to assess fuel quality were volatility, ethanol content, water content, acidity, pHe, inorganic chloride and sulfate, and total sulfate. Class 1 samples more often met the volatility specification than samples from other classes, with 67% of the samples collected in this study meeting the specification. Samples in Classes 2 and 3 met the applicable volatility specifications on 43% and 30% of the time, respectively. Compliance with the ethanol specification was almost 90% in all three volatility classes, a significant improvement over previous surveys. Several samples that would have been off-specification for ethanol content under previous versions of the specification now met the specification with the reduction in ethanol content for all classes. A few samples were off-specification for pHe, acidity, water, and inorganic chloride. Few samples were off-specification for more than one property, and samples that were off-specification in one volatility class were not necessarily off-specification in the other two classes.
Date: December 1, 2011
Creator: Alleman, T. L.
Object Type: Report
System: The UNT Digital Library
The nature of the lightest scalar meson, its N_c behaviour and semi-local duality (open access)

The nature of the lightest scalar meson, its N_c behaviour and semi-local duality

One-loop unitarized Chiral Perturbation Theory (UChPT) calculations, suggest a different N{sub c} behaviour for the {sigma} or f{sub 0}(600) and {rho}(770) mesons: while the {rho} meson becomes narrower with N{sub c}, as expected for a {bar q}q meson, the f{sub 0}(600) contribution to the total cross section below 1 GeV becomes less and less important. Here we review our recent work where we have shown, by means of finite energy sum rules, that a different N{sub c} behavior for these resonances may lead to a conflict with semi-local duality for large N{sub c}, since local duality requires a cancellation between the f{sub 0}(600) and {rho}(770) amplitudes. However, UChPT calculations also suggest a subdominant {bar q}q component for the f{sub 0}(600) with a mass above 1 GeV and this can restore semi-local duality, as we show.
Date: December 1, 2011
Creator: JR Pelaez, MR Pennington, J Ruiz de Elvira, DJ Wilson
Object Type: Article
System: The UNT Digital Library
Reflector Technology Development and System Design for Concentrating Solar Power Technologies (open access)

Reflector Technology Development and System Design for Concentrating Solar Power Technologies

Alcoa began this program in March of 2008 with the goal of developing and validating an advanced CSP trough design to lower the levelized cost of energy (LCOE) as compared to existing glass based, space-frame trough technology. In addition to showing a pathway to a significant LCOE reduction, Alcoa also desired to create US jobs to support the emerging CSP industry. Alcoa's objective during Phase I: Concept Feasibility was to provide the DOE with a design approach that demonstrates significant overall system cost savings without sacrificing performance. Phase I consisted of two major tasks; reflector surface development and system concept development. Two specific reflective surface technologies were investigated, silver metallized lamination, and thin film deposition both applied on an aluminum substrate. Alcoa prepared samples; performed test validation internally; and provided samples to the NREL for full-spectrum reflectivity measurements. The final objective was to report reflectivity at t = 0 and the latest durability results as of the completion of Phase 1. The target criteria for reflectance and durability were as follows: (1) initial (t = 0), hemispherical reflectance >93%, (2) initial spectral reflectance >90% for 25-mrad reading and >87% for 7-mrad reading, and (3) predicted 20 year durability of less …
Date: December 30, 2011
Creator: Schaut, Adam & Smith, Philip
Object Type: Report
System: The UNT Digital Library
Femtosecond X-ray Pulse Temporal Characterization in Free-Electron Lasers Using a Transverse Deflector (open access)

Femtosecond X-ray Pulse Temporal Characterization in Free-Electron Lasers Using a Transverse Deflector

We propose a novel method to characterize the temporal duration and shape of femtosecond x-ray pulses in a free-electron laser (FEL) by measuring the time-resolved electron-beam energy loss and energy spread induced by the FEL process, with a transverse radio-frequency deflector located after the undulator. Its merits are simplicity, high resolution, wide diagnostic range, and non-invasive to user operation. When the system is applied to the Linac Coherent Light Source, the first hard x-ray free-electron laser in the world, it can provide single-shot measurements on the electron beam and x-ray pulses with a resolution on the order of 1-2 femtoseconds rms.
Date: December 13, 2011
Creator: Ding, Y.; Behrens, C.; Emma, P.; Frisch, J.; Huang, Z.; Loos, H. et al.
Object Type: Article
System: The UNT Digital Library
Evaluations of University of Wisconsin Silicon Carbide Temperature Monitors 300 LO and 400 LO B (open access)

Evaluations of University of Wisconsin Silicon Carbide Temperature Monitors 300 LO and 400 LO B

Silicon carbide (SiC) temperature monitors 05R4-02-A KG1403 (300 LO) and 05R4-01-A KG1415 (400 LO B) were evaluated at the High Temperature Test Lab (HTTL) to determine their peak irradiation temperatures. HTTL measurements indicate that the peak irradiation temperature for the 300 LO monitor was 295 {+-} 20 C and the peak irradiation temperature for the 400 LO B monitor was 294 {+-} 25 C. Two silicon carbide (SiC) temperature monitors irradiated in the Advanced Test Reactor (ATR) were evaluated at the High Temperature Test Lab (HTTL) to determine their peak temperature during irradiation. These monitors were irradiated as part of the University of Wisconsin Pilot Project with a target dose of 3 dpa. Temperature monitors were fabricated from high density (3.203 g/cm3) SiC manufactured by Rohm Haas with a nominal size of 12.5 mm x 1.0 mm x 0.75 mm (see Attachment A). Table 1 provides identification for each monitor with an expected peak irradiation temperature range based on preliminary thermal analysis (see Attachment B). Post irradiation calculations are planned to reduce uncertainties in these calculated temperatures. Since the early 1960s, SiC has been used as a post-irradiation temperature monitor. As noted in Reference 2, several researchers have observed that …
Date: December 1, 2011
Creator: Davis, K. L.; Rempe, J. L.; Knudson, D. L.; Chase, B. M. & Unruh, T. C.
Object Type: Report
System: The UNT Digital Library
Search for universal extra dimensions in ppbar collisions (open access)

Search for universal extra dimensions in ppbar collisions

We present a search for Kaluza-Klein (KK) particles predicted by models with universal extra dimensions (UED) using a data set corresponding to an integrated luminosity of 7.3 fb{sup -1}, collected by the D0 detector at a p{bar p} center of mass energy of 1.96 TeV. The decay chain of KK particles can lead to a final state with two muons of the same charge. This signature is used to set a lower limit on the compactification scale of R{sup -1} > 260 GeV in a minimal UED model.
Date: December 1, 2011
Creator: Abazov, Victor Mukhamedovich; /Dubna, JINR; Abbott, Braden Keim; U., /Oklahoma; Acharya, Bannanje Sripath; Inst., /Tata et al.
Object Type: Article
System: The UNT Digital Library
Theory of Microwave Instability and Coherent Synchrotron Radiation in Electron Storage Rings (open access)

Theory of Microwave Instability and Coherent Synchrotron Radiation in Electron Storage Rings

Bursting of coherent synchrotron radiation has been observed and in fact used to generate THz radiation in many electron storage rings. In order to understand and control the bursting, we return to the study of the microwave instability. In this paper, we will report on the theoretical understanding, including recent developments, of the microwave instability in electron storage rings. The historical progress of the theories will be surveyed, starting from the dispersion relation of coasting beams, to the work of Sacherer on a bunched beam, and ending with the Oide and Yokoya method of discretization. This theoretical survey will be supplemented with key experimental results over the years. Finally, we will describe the recent theoretical development of utilizing the Laguerre polynomials in the presence of potential-well distortion. This self-consistent method will be applied to study the microwave instability driven the impedances due to the coherent synchrotron radiation. Over the past quarter century, there has been steady progress toward smaller transverse emittances in electron storage rings used for synchrotron light sources, from tens of nm decades ago to the nm range recently. In contrast, there is not much progress made in the longitudinal plane. For an electron bunch in a typical …
Date: December 9, 2011
Creator: Cai, Y.
Object Type: Article
System: The UNT Digital Library
EnergySavers: Tips on Saving Money & Energy at Home (Brochure) (open access)

EnergySavers: Tips on Saving Money & Energy at Home (Brochure)

The U.S. Department of Energy's consumer guide to saving money and energy at home and on the road. It consists of the following articles: (1) Save Money and Energy Today - Get started with things you can do now, and use the whole-house approach to ensure that your investments are wisely made to save you money and energy; (2) Your Home's Energy Use - Find out how your home uses energy, and where it's losing the most energy so you can develop a plan to save in the short and long term; (3) Air Leaks and Insulation - Seal air leaks and insulate your home properly so your energy dollars don't seep through the cracks; (4) Heating and Cooling - Use efficient systems to heat and cool your home, and save money and increase comfort by properly maintaining and upgrading equipment; (5) Water Heating - Use the right water heater for your home, insulate it and lower its temperature, and use less water to avoid paying too much; (6) Windows - Enjoy light and views while saving money by installing energy-efficient windows, and use strategies to keep your current windows from losing energy; (7) Lighting - Choose today's energy-efficient lighting …
Date: December 1, 2011
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Structural considerations for solar installers : an approach for small, simplified solar installations or retrofits. (open access)

Structural considerations for solar installers : an approach for small, simplified solar installations or retrofits.

Structural Considerations for Solar Installers provides a comprehensive outline of structural considerations associated with simplified solar installations and recommends a set of best practices installers can follow when assessing such considerations. Information in the manual comes from engineering and solar experts as well as case studies. The objectives of the manual are to ensure safety and structural durability for rooftop solar installations and to potentially accelerate the permitting process by identifying and remedying structural issues prior to installation. The purpose of this document is to provide tools and guidelines for installers to help ensure that residential photovoltaic (PV) power systems are properly specified and installed with respect to the continuing structural integrity of the building.
Date: December 1, 2011
Creator: Richards, Elizabeth H.; Schindel, Kay; Bosiljevac, Tom; Dwyer, Stephen F.; Lindau, William & Harper, Alan
Object Type: Report
System: The UNT Digital Library
Scientific Discovery with the Blue Gene/L (open access)

Scientific Discovery with the Blue Gene/L

This project succeeded in developing key software optimization tools to bring fundamental QCD calculations of nucleon structure from the Terascale era through the Petascale era and prepare for the Exascale era. It also enabled fundamental QCD physics calculations and demonstrated the power of placing small versions of frontier emerging architectures at MIT to attract outstanding students to computational science. MIT also hosted a workshop September 19 2008 to brainstorm ways to promote computational science at top tier research universities and attract gifted students into the field, some of whom would provide the next generation of talent at our defense laboratories.
Date: December 9, 2011
Creator: Negele, John W.
Object Type: Report
System: The UNT Digital Library
Solar Thermochemical Fuels Production: Solar Thermochemical Fuel Production via a Novel Lowe Pressure, Magnetically Stabilized, Non-volatile Iron Oxide Looping Process (open access)

Solar Thermochemical Fuels Production: Solar Thermochemical Fuel Production via a Novel Lowe Pressure, Magnetically Stabilized, Non-volatile Iron Oxide Looping Process

HEATS Project: The University of Florida is developing a windowless high-temperature chemical reactor that converts concentrated solar thermal energy to syngas, which can be used to produce gasoline. The overarching project goal is lowering the cost of the solar thermochemical production of syngas for clean and synthetic hydrocarbon fuels like petroleum. The team will develop processes that rely on water and recycled CO2 as the sole feed-stock, and concentrated solar radiation as the sole energy source, to power the reactor to produce fuel efficiently. Successful large-scale deployment of this solar thermochemical fuel production could substantially improve our national and economic security by replacing imported oil with domestically produced solar fuels.
Date: December 19, 2011
Creator: unknown
Object Type: Text
System: The UNT Digital Library
Theoretical study of proton beam preparation for the g-2 experiment (open access)

Theoretical study of proton beam preparation for the g-2 experiment

Beam preparation for the g-2 experiment is studied. Because of limited 2.5-MHz rf voltage and the 66-ms limited time duration allowance for the whole process, the Booster batch must be first captured to a lower 2.5-MHz rf voltage followed by a rotation in the 2.5-MHz bucket in order to achieve the required narrow half bunch width of 50 ns. The appearance of bunch tails can be reduced by first rotation by a linear barrier voltage before the adiabatic capture.
Date: December 1, 2011
Creator: Ng, King-Yuen
Object Type: Report
System: The UNT Digital Library
Degradation of Thermal Barrier Coatings from Deposits and Its Mitigation (open access)

Degradation of Thermal Barrier Coatings from Deposits and Its Mitigation

Ceramic thermal barrier coatings (TBCs) used in gas-turbine engines afford higher operating temperatures, resulting in enhanced efficiencies and performance. However, in the case of syngas-fired engines, fly ash particulate impurities that may be present in syngas can melt on the hotter TBC surfaces and form glassy deposits. These deposits can penetrate the TBCs leading to their failure. In experiments using lignite fly ash to simulate these conditions we show that conventional TBCs of composition 93wt% ZrO{sub 2} + 7wt% Y{sub 2}O{sub 3} (7YSZ) fabricated using the air plasma spray (APS) process are completely destroyed by the molten fly ash. The molten fly ash is found to penetrate the full thickness of the TBC. The mechanisms by which this occurs appear to be similar to those observed in degradation of 7YSZ TBCs by molten calcium-magnesium-aluminosilicate (CMAS) sand and by molten volcanic ash in aircraft engines. In contrast, APS TBCs of Gd{sub 2}Zr{sub 2}O{sub 7} composition are highly resistant to attack by molten lignite fly ash under identical conditions, where the molten ash penetrates ~25% of TBC thickness. This damage mitigation appears to be due to the formation of an impervious, stable crystalline layer at the fly ash/Gd{sub 2}Zr{sub 2}O{sub 7} TBC …
Date: December 31, 2011
Creator: Padture, Nitin
Object Type: Report
System: The UNT Digital Library