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Coast Guard: Station Readiness Improving, but Resource Challenges and Management Concerns Remain (open access)

Coast Guard: Station Readiness Improving, but Resource Challenges and Management Concerns Remain

A letter report issued by the Government Accountability Office with an abstract that begins "For years, the Coast Guard has conducted search and rescue operations from its network of stations along the nation's coasts and waterways. In 2001, reviews of station operations found that station readiness--the ability to execute mission requirements in keeping with standards--was in decline. The Coast Guard began addressing these issues, only to see its efforts complicated by expanded post-September 11, 2001, homeland security responsibilities at many stations. GAO reviewed the impact of changing missions on station needs, the progress made in addressing station readiness needs, and the extent to which plans are in place for addressing any remaining needs."
Date: January 31, 2005
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Criminal Debt: Court-Ordered Restitution Amounts Far Exceed Likely Collections for the Crime Victims in Selected Financial Fraud Cases (open access)

Criminal Debt: Court-Ordered Restitution Amounts Far Exceed Likely Collections for the Crime Victims in Selected Financial Fraud Cases

A letter report issued by the Government Accountability Office with an abstract that begins "In the wake of a recent wave of corporate scandals, Senator Byron L. Dorgan noted that the American taxpayers have a right to expect that those who have committed corporate fraud and other criminal wrongdoing will be punished, and that the federal government will make every effort to recover assets held by the offenders. Recognizing that GAO previously reported on deficiencies in the Department of Justice's (Justice) criminal debt collection processes (GAO-01-664), Senator Dorgan asked GAO to review selected criminal white-collar financial fraud cases for which large restitution debts have been established but little has been collected. Specifically, GAO was asked to determine (1) the status of Justice's efforts to collect on the outstanding debt, (2) the prospects for future collections, and (3) whether specific problems have affected Justice's ability to collect the debt."
Date: January 31, 2005
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Army National Guard: Inefficient, Error-Prone Process Results in Travel Reimbursement Problems for Mobilized Soldiers (open access)

Army National Guard: Inefficient, Error-Prone Process Results in Travel Reimbursement Problems for Mobilized Soldiers

A letter report issued by the Government Accountability Office with an abstract that begins "GAO was asked to determine (1) the impact of the recent increased operational tempo on the process used to reimburse Army Guard soldiers for travel expenses and the effect that travel reimbursement problems have had on soldiers and their families; (2) the adequacy of the overall design of controls over the processes, human capital, and automated systems relied on for Army Guard travel reimbursements; and (3) whether the Department of Defense's (DOD) current efforts to automate its travel reimbursement process will resolve the problems identified. GAO selected and audited 10 case study units that were identified in a preliminary assessment as having a variety of travel reimbursement problems."
Date: January 31, 2005
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Social Security Administration: Actions Needed to Strengthen Processes for Issuing Social Security Numbers to Children (open access)

Social Security Administration: Actions Needed to Strengthen Processes for Issuing Social Security Numbers to Children

A letter report issued by the Government Accountability Office with an abstract that begins "In fiscal year 2004, the Social Security Administration (SSA) issued about 4.2 million original Social Security numbers (SSN) and 2 million SSN replacement cards to U.S.-born children. Despite its narrowly intended purpose, today, young children need a SSN to be claimed on their parent's income tax return or to apply for certain government benefits. Because children's SSNs, like all SSNs, are vulnerable to theft and misuse, the Chairman of the Senate Committee on Finance requested that GAO (1) document SSA's current processes and internal controls for issuing SSNs to U.S.-born children under the age of 18 and (2) identify any weaknesses that may affect SSA's ability to ensure the integrity of the SSN and the efficiency of enumeration processes."
Date: January 31, 2005
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Wastewater Facilities: Experts' Views on How Federal Funds Should Be Spent to Improve Security (open access)

Wastewater Facilities: Experts' Views on How Federal Funds Should Be Spent to Improve Security

A chapter report issued by the Government Accountability Office with an abstract that begins "Since the events of September 11, 2001, the security of the nation's drinking water and wastewater infrastructure has received increased attention from Congress and the executive branch. Wastewater facilities in the United States provide essential services to residential, commercial, and industrial users by collecting and treating wastewater and discharging it into receiving waters. These facilities, however, may possess certain characteristics that terrorists could exploit either to impair the wastewater treatment process or to damage surrounding communities and infrastructure. GAO was asked to obtain experts' views on (1) the key security-related vulnerabilities affecting the nation's wastewater systems, (2) the activities the federal government should support to improve wastewater security, and (3) the criteria that should be used to determine how any federal funds are allocated to improve security, and the best methods to distribute these funds. GAO conducted a systematic, Web-based survey of 50 nationally recognized experts to seek consensus on these key wastewater security issues. EPA expressed general agreement with the report, citing its value as the agency works with its partners to better secure the nation's critical wastewater infrastructure."
Date: January 31, 2005
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Federal-Aid Highways: FHWA Needs a Comprehensive Approach to Improving Project Oversight (open access)

Federal-Aid Highways: FHWA Needs a Comprehensive Approach to Improving Project Oversight

A letter report issued by the Government Accountability Office with an abstract that begins "The federal-aid highway program provides over $25 billion a year to states for highway and bridge projects, often paying 80 percent of these projects' costs. The federal government provides funding for and oversees this program, while states largely choose and manage the projects. Ensuring that states effectively control the cost and schedule performance of these projects is essential to ensuring that federal funds are used efficiently. We reviewed the Federal Highway Administration's (FHWA) approach to improving its federal-aid highway project oversight efforts since we last reported on it in 2002, including (1) FHWA's oversight-related goals and performance measures, (2) FHWA's oversight improvement activities, (3) challenges FHWA faces in improving project oversight, and (4) best practices for project oversight."
Date: January 31, 2005
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Issues in Aging: Unemployment and Older Workers (open access)

Issues in Aging: Unemployment and Older Workers

None
Date: January 31, 2005
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Final Report Providing the Design for Low-Cost Wireless Current Transducer and Electric Power Sensor Prototype (open access)

Final Report Providing the Design for Low-Cost Wireless Current Transducer and Electric Power Sensor Prototype

This report describes the design and development of a wireless current transducer and electric power sensor prototype. The report includes annotated schematics of the power sensor circuitry and the printed circuit board. The application program used to illustrate the functionality of the wireless sensors is described in this document as well.
Date: January 31, 2005
Creator: Kintner-Meyer, Michael CW; Burghard, Brion J. & Reid, Larry D.
Object Type: Report
System: The UNT Digital Library
Advancing New 3D Seismic Interpretation Methods for Exploration and Development of Fractured Tight Gas Reservoirs (open access)

Advancing New 3D Seismic Interpretation Methods for Exploration and Development of Fractured Tight Gas Reservoirs

In a study funded by the U.S. Department of Energy and GeoSpectrum, Inc., new P-wave 3D seismic interpretation methods to characterize fractured gas reservoirs are developed. A data driven exploratory approach is used to determine empirical relationships for reservoir properties. Fractures are predicted using seismic lineament mapping through a series of horizon and time slices in the reservoir zone. A seismic lineament is a linear feature seen in a slice through the seismic volume that has negligible vertical offset. We interpret that in regions of high seismic lineament density there is a greater likelihood of fractured reservoir. Seismic AVO attributes are developed to map brittle reservoir rock (low clay) and gas content. Brittle rocks are interpreted to be more fractured when seismic lineaments are present. The most important attribute developed in this study is the gas sensitive phase gradient (a new AVO attribute), as reservoir fractures may provide a plumbing system for both water and gas. Success is obtained when economic gas and oil discoveries are found. In a gas field previously plagued with poor drilling results, four new wells were spotted using the new methodology and recently drilled. The wells have estimated best of 12-months production indicators of 2106, …
Date: January 31, 2005
Creator: Reeves, James
Object Type: Report
System: The UNT Digital Library
Space-time thermodynamics of the glass transition (open access)

Space-time thermodynamics of the glass transition

We consider the probability distribution for the fluctuations in the dynamical action of glass forming materials. We argue that the so-called glass transition is a manifestation of low action tails in these distributions where the entropy of trajectory space is sub-extensive in time. These low action tails are a consequence of dynamic heterogeneity and an indication of phase coexistence in trajectory space. The glass transition, where the system falls out of equilibrium, is then an order-disorder phenomenon in space-time occurring at a temperature T{sub g} which is a weak function of measurement time. We illustrate our perspective ideas with facilitated lattice models, and note how these ideas apply more generally.
Date: January 31, 2005
Creator: Merolle, Mauro; Garrahan, Juan P. & Chandler, David
Object Type: Article
System: The UNT Digital Library
Occupational Safety Review of High Technology Facilities (open access)

Occupational Safety Review of High Technology Facilities

This report contains reviews of operating experiences, selected accident events, and industrial safety performance indicators that document the performance of the major US DOE magnetic fusion experiments and particle accelerators. These data are useful to form a basis for the occupational safety level at matured research facilities with known sets of safety rules and regulations. Some of the issues discussed are radiation safety, electromagnetic energy exposure events, and some of the more widespread issues of working at height, equipment fires, confined space work, electrical work, and other industrial hazards. Nuclear power plant industrial safety data are also included for comparison.
Date: January 31, 2005
Creator: Cadwallader, Lee
Object Type: Report
System: The UNT Digital Library
Optimizing Technology to Reduce Mercury and Acid Gas Emissions from Electric Power Plants (open access)

Optimizing Technology to Reduce Mercury and Acid Gas Emissions from Electric Power Plants

Revised maps and associated data show potential mercury, sulfur, and chlorine emissions for U.S. coal by county of origin. Existing coal mining and coal washing practices result in a 25% reduction of mercury in U.S. coal before it is delivered to the power plant. Selection of low-mercury coal is a good mercury control option for plants having hot-side ESP, cold-side ESP, or hot-side ESP/FGD emission controls. Chlorine content is more important for plants having cold-side ESP/FGD or SDA/FF controls; optimum net mercury capture is indicated where chlorine is between 500 and 1000 ppm. Selection of low-sulfur coal should improve mercury capture where carbon in fly ash is used to reduce mercury emissions.
Date: January 31, 2005
Creator: Quick, Jeffrey C.; Tabet, David E.; Wakefield, Sharon & Bon, Roger L.
Object Type: Report
System: The UNT Digital Library
The low cost of geological assessment for underground CO2 storage: Policy and economic implications (open access)

The low cost of geological assessment for underground CO2 storage: Policy and economic implications

The costs for carbon dioxide (CO{sub 2}) capture and storage (CCS) in geologic formations is estimated to be $6-75/t CO{sub 2}. In the absence of a mandate to reduce greenhouse gas emissions or some other significant incentive for CCS deployment, this cost effectively limits CCS technology deployment to small niche markets and stymies the potential for further technological development through learning-by-doing until these disincentives for the free venting of CO{sub 2} are in place. By far, the largest current fraction of these costs is capture (including compression and dehydration), commonly estimated at $25-60/t CO{sub 2} for power plant applications followed by CO{sub 2} transport and storage, estimated at $0-15/t CO{sub 2}. Of the storage costs, only a small fraction of the cost will go to accurate geological characterization. These one-time costs are probably on the order of $0.1/t CO{sub 2} or less as these costs are spread out over the many millions of tons likely to be injected into a field over many decades. Geologic assessments include information central to capacity prediction, risk estimation for the target intervals, and development facilities engineering. Since assessment costs are roughly 2 orders of magnitude smaller than capture costs, and assessment products carry other …
Date: January 31, 2005
Creator: Friedmann, S J; Dooley, J; Held, H & Edenhofer, O
Object Type: Article
System: The UNT Digital Library
A REVIEW OF THE MEASUREMENT AND DEVELOPMENT OF CRYSTALLINITY AND ITS RELATION TO PROPERTIES IN NEAT POLY(PHENYLENE SULFIDE) AND ITS FIBER REINFORCED COMPOSITES (open access)

A REVIEW OF THE MEASUREMENT AND DEVELOPMENT OF CRYSTALLINITY AND ITS RELATION TO PROPERTIES IN NEAT POLY(PHENYLENE SULFIDE) AND ITS FIBER REINFORCED COMPOSITES

This literature review paper was prepared for the Department of Energy Automotive Lightweighting Program to address materials interest expressed by the Automotive Composites Consortium and it summarizes the measurement and development of crystallinity and its relation to properties in poly(phenylene sulfide) (PPS) and its fiber reinforced composites. The objective of this effort was to broaden the understanding of low-cost, semi-crystalline thermoplastic resins and composites for use in potential future automotive applications. PPS has an excellent combination of attributes including good mechanical properties and thermal stability, high chemical resistance, low moisture absorption, good weathering resistance, high dimensional stability, low flammability, and excellent processability. Specific areas addressed in this report include: Structure of PPS; Techniques for measuring crystallinity; Crystallinity as a function of prior treatment; Crystallization kinetics and morphology; Effect of variation of crystallinity on properties of PPS and its composites; Environmental stability; Unusual effects of cooling rates and degree of crystallinity on mechanical properties of AS4/PPS composites; Recent PPS laminate data (Ten Cate Advanced Composites); and Recommendations for future research.
Date: January 31, 2005
Creator: Spruiell, J.E.
Object Type: Report
System: The UNT Digital Library
Elevated-Temperature Ferritic and Martensitic Steels and Their Application to Future Nuclear Reactors (open access)

Elevated-Temperature Ferritic and Martensitic Steels and Their Application to Future Nuclear Reactors

In the 1970s, high-chromium (9-12% Cr) ferritic/martensitic steels became candidates for elevated-temperature applications in the core of fast reactors. Steels developed for conventional power plants, such as Sandvik HT9, a nominally Fe-12Cr-1Mo-0.5W-0.5Ni-0.25V-0.2C steel (composition in wt %), were considered in the United States, Europe, and Japan. Now, a new generation of fission reactors is in the planning stage, and ferritic, bainitic, and martensitic steels are again candidates for in-core and out-of-core applications. Since the 1970s, advances have been made in developing steels with 2-12% Cr for conventional power plants that are significant improvements over steels originally considered. This paper will review the development of the new steels to illustrate the advantages they offer for the new reactor concepts. Elevated-temperature mechanical properties will be emphasized. Effects of alloying additions on long-time thermal exposure with and without stress (creep) will be examined. Information on neutron radiation effects will be discussed as it applies to ferritic and martensitic steels.
Date: January 31, 2005
Creator: Klueh, RL
Object Type: Report
System: The UNT Digital Library
Hardness of Carburized Surfaces in 316LN Stainless Steel after Low Temperature Neutron Irradiation (open access)

Hardness of Carburized Surfaces in 316LN Stainless Steel after Low Temperature Neutron Irradiation

A proprietary surface carburization treatment is being considered to minimize possible cavitation pitting of the inner surfaces of the stainless steel target vessel of the SNS. The treatment gives a large supersaturation of carbon in the surface layers and causes substantial hardening of the surface. To answer the question of whether such a hardened layer will remain hard and stable during neutron irradiation, specimens of the candidate materials were irradiated in the High Flux Isotope Reactor (HFIR) to an atomic displacement level of 1 dpa. Considerable radiation hardening occurred in annealed 316LN stainless steel and 20% cold rolled 316LN stainless steel, and lesser radiation hardening in Kolsterised layers on these materials. These observations coupled with optical microscopy examinations indicate that the carbon-supersaturated layers did not suffer radiation-induced decomposition and softening.
Date: January 31, 2005
Creator: Byun, TS
Object Type: Report
System: The UNT Digital Library
A Widely Tunable Infrared Laser Spectrometer for Measurements of Isotopic Ratios of Carbon Cycle Gases (open access)

A Widely Tunable Infrared Laser Spectrometer for Measurements of Isotopic Ratios of Carbon Cycle Gases

The atmospheric abundances of carbon dioxide and methane have increased dramatically during the industrial era. Measurements of the isotopic composition of these gases can provide a powerful tool for quantifying their sources and sinks. This report describes the development of a portable instrument for isotopic analysis CO{sub 2} and CH{sub 4} using tunable infrared laser absorption spectroscopy. This instrument combines novel optical design and signal processing methods with a widely tunable mid-infrared laser source based on difference frequency generation (DFG) which will can access spectral regions for all the isotopes of CO{sub 2} and CH{sub 4} with a single instrument. The instrument design compensates for the large difference in concentration between major and minor isotopes by measuring them with path lengths which differ by a factor of 100 within the same multipass cell. During Phase I we demonstrated the basic optical design and signal processing by determining {sup 13}CO{sub 2} isotopic ratios with precisions as small as 0.2{per_thousand} using a conventional lead salt diode laser. During Phase II, the DFG laser source was coupled with the optical instrument and was demonstrated to detect {sup 13}CH{sub 4}/{sup 12}CH{sub 4} ratios with a precision of 0.5{per_thousand} and an averaging time of 20 …
Date: January 31, 2005
Creator: Shorter, Joanne H.; McManus, J. Barry; Nelson, David D.; Kolb, Charles E.; Zahniser, Mark S.; Bambha, Ray et al.
Object Type: Report
System: The UNT Digital Library
NANOSTRUCTURED CERAMICS AND COMPOSITES FOR REFRACTORY APPLICATIONS IN COAL GASIFICATION (open access)

NANOSTRUCTURED CERAMICS AND COMPOSITES FOR REFRACTORY APPLICATIONS IN COAL GASIFICATION

A class of ceramics, capable of exhibiting low coefficients of thermal expansion and catalytic properties was investigated. Investigations were directed towards nanoengineering of NZP ceramics and NZP-based composites by chemical means by controlling their compositions and processing variables. NaZr{sub 2}(PO{sub 4}){sub 3} (NZP) was synthesized by combining water-soluble precursors leading to the precipitation of a gel that was dried, calcined, pressed into pellets, then fired at 850 C. Without chemical additives, the resulting ceramic comprised pores ranging in size from approximately 25 to 50 nm and a surface area of about 30m{sup 2}/g. Hydroxyapatite, which has a needle-like morphology, was mechanically mixed with the calcined gel to template NZP crystallization. What resulted was a coarsening of the pore structure and a decrease in surface area. When copper nitrate was added to the solution during synthesis, the resulting ceramic underwent shrinkage upon firing as well as an increase in strength. HAp and copper additions combined resulted in 40% volume shrinkage and a doubling of the tensile strength to 16MPa. A very different type of porosity was achieved when silica was partly substituted for phosphorous in the NZP structure. Na{sub 3}Zr{sub 2}(Si{sub 2}P)O{sub 12} (NASCION) was synthesized in the same manner as …
Date: January 31, 2005
Creator: Brown, Paul
Object Type: Report
System: The UNT Digital Library
Applying Current Human Factors Engineering Guidance to Control Room Design (open access)

Applying Current Human Factors Engineering Guidance to Control Room Design

The Westinghouse Savannah River Company, a contractor to the Department of Energy, has compared Revisions 1 and 2 of NUREG-0700-Human System Interface Design Review Guideline, from the United States Nuclear Regulatory Commission Nuclear Regulatory Guide. The comparison has been made with respect to which guidelines remained the same, the guidelines that were reformatted or reworded, additional guidelines, and deleted guidelines. This comparison was made in preparation of revising the previously developed Human Factors Engineering Analysis Tool for automating the review, analysis, and evaluation of human system interface designs. This tool has been described at previous conferences on human factors and the merits and benefits of the tool described. The tool has been successfully applied to over eight facilities at WSRC. This paper describes the methodology and results of the comparison and the plans to enhance the already successful automation tool. The number of criteria in NUREG-0700 increased from approximately 1650 in Revision 1 to almost 2200 in Revision 2. Approximately 1600 criteria remained the same, though they were significantly reorganized; while about 100 were reworded or reformatted to clarify or expand the guidance provided. Around 600 guidelines were added and approximately 70 deleted. The majority of the changes and additions …
Date: January 31, 2005
Creator: Leo, Geary
Object Type: Article
System: The UNT Digital Library
Advanced Strained-Superlattice Photocathodes for Polarized Electron Sources (open access)

Advanced Strained-Superlattice Photocathodes for Polarized Electron Sources

Polarized electrons have been essential for high-energy parity-violating experiments and measurements of the nucleon spin structure. The availability of a polarized electron beam was crucial to the success of the Stanford Linear Collider (SLC) in achieving a precise measurement of the electroweak mixing angle, and polarized electron beams will be required for all future linear colliders. Polarized electrons are readily produced by GaAs photocathode sources. When a circularly polarized laser beam tuned to the bandgap minimum is directed to the negative-electron-affinity (NEA) surface of a GaAs crystal, longitudinally polarized electrons are emitted into vacuum. The electron polarization is easily reversed by reversing the laser polarization. The important properties of these photocathodes for accelerator applications are: degree of polarization of the extracted beam; ability to extract sufficient charge to meet accelerator pulse-structure requirements; efficiency and stability of operation; and absence of any asymmetries in the beam properties (charge, position, energy, etc.) upon polarization reversal. The performance of GaAs photocathodes has improved significantly since they were first introduced in 1978 [1]. The theoretical maximum polarization of 50% for natural GaAs was first exceeded in 1991 using the lattice mismatch of a thin InGaAs layer epitaxially grown over a GaAs substrate to generate …
Date: January 31, 2005
Creator: Moy, Dr. Aaron
Object Type: Report
System: The UNT Digital Library
An Advanced Fracture Characterization and Well Path Navigation System for Effective Re-Development and Enhancement of Ultimate Recovery From the Complex Monterey Reservoir of South Ellwood Field, Offshore California, Quarterly Report: October - December 2004 (open access)

An Advanced Fracture Characterization and Well Path Navigation System for Effective Re-Development and Enhancement of Ultimate Recovery From the Complex Monterey Reservoir of South Ellwood Field, Offshore California, Quarterly Report: October - December 2004

Venoco Inc, intends to re-develop the Monterey Formation, a Class III basin reservoir, at South Ellwood Field, Offshore Santa Barbara, California. Well productivity in this field varies significantly. Cumulative Monterey production for individual wells has ranged from 260 STB to 8,700,000 STB. Productivity is primarily affected by how well the well path connects with the local fracture system and the degree of aquifer support. Cumulative oil recovery to date is a small percentage of the original oil in place. To embark upon successful re-development and to optimize reservoir management, Venoco intends to investigate, map and characterize field fracture patterns and the reservoir conduit system. State of the art borehole imaging technologies including FMI, dipole sonic and cross-well seismic, interference tests and production logs will be employed to characterize fractures and micro faults. These data along with the existing database will be used for construction of a novel geologic model of the fracture network. Development of an innovative fracture network reservoir simulator is proposed to monitor and manage the aquifer's role in pressure maintenance and water production. The new fracture simulation model will be used for both planning optimal paths for new wells and improving ultimate recovery. In the second phase …
Date: January 31, 2005
Creator: Horner, Steve
Object Type: Report
System: The UNT Digital Library
Distributed Physical and Molecular Separations for Selective Harvest of Higher Value Wheat Straw Components Project (open access)

Distributed Physical and Molecular Separations for Selective Harvest of Higher Value Wheat Straw Components Project

Wheat straw (Triticum aestivum L.) is an abundant source of plant fiber. It is regenerated, in large quantities, every year. At present, this potentially valuable resource is greatly under-exploited. Most of the excess straw biomass (i.e., tonnage above that required for agronomic cropping system sustainability) is managed through expensive chopping/tillage operations and/or burnt in the field following harvest, resulting in air pollution and associated health problems. Potential applications for wheat straw investigated within this project include energy and composites manufacture. Other methods of straw utilization that will potentially benefit from the findings of this research project include housing and building, pulp and paper, thermal insulation, fuels, and chemicals. This project focused on components of the feedstock assembly system for supplying a higher value small grains straw residue for (1) gasification/combustion and (2) straw-thermoplastic composites. This project was an integrated effort to solve the technological, infrastructural, and economic challenges associated with using straw residue for these bioenergy and bioproducts applications. The objective of the research is to contribute to the development of a low-capital distributed harvesting and engineered storage system for upgrading wheat straw to more desirable feedstocks for combustion and for straw-plastic composites. We investigated two processes for upgrading wheat …
Date: January 31, 2005
Creator: Hess, J.R
Object Type: Report
System: The UNT Digital Library
Impermeable thin AI2O3 overlay for TBC protection from sulfate and vanadate attack in gas turbines (open access)

Impermeable thin AI2O3 overlay for TBC protection from sulfate and vanadate attack in gas turbines

25 {micro}m and a 2 {micro}m thick Al{sub 2}O{sub 3} overlay were deposited by HVOF thermal spray and by sol-gel coating method, respectively, onto to the surface of YSZ coating. Indenter test was employed to investigate the spalling of YSZ with and without Al{sub 2}O{sub 3} overlay after hot corrosion. The results showed that Al{sub 2}O{sub 3} overlay acted as a barrier against the infiltration of the molten salt into the YSZ coating during exposure, thus significantly reduced the amount of M-phase of ZrO{sub 2} in YSZ coating. Thick Al{sub 2}O{sub 3} overlay will increase compressive stress and failure in TBC. During next reporting time, Al{sub 2}O{sub 3} overlay will be deposited on the YSZ surface by the composite-sol-gel route (CSG). Hot corrosion tests will be carried out on the TBC.
Date: January 31, 2005
Creator: Mao, Scott X.
Object Type: Report
System: The UNT Digital Library
Co-continuous Metal-Ceramic Nanocomposites (open access)

Co-continuous Metal-Ceramic Nanocomposites

A room temperature technique was developed to produce continuous metal nanowires embedded in random nanoporous ceramic skeletons. The synthesis involves preparation of uniform, nanoporous ceramic preforms, and subsequent electrochemical metal infiltration at room temperature, so to avoid materials incompatibilities frequently encountered in traditional high temperature liquid metal infiltration. Structure and preliminary evaluations of mechanical and electronic properties of copper/alumina nanocomposites are reported.
Date: January 31, 2005
Creator: Zhang, Xiao Feng; Harley, Gabriel & De Jonghe, Lutgard C.
Object Type: Article
System: The UNT Digital Library