Development of a Whole-Wafer, Macroscale Inspection Software Method for Semiconductor Wafer Analysis (open access)

Development of a Whole-Wafer, Macroscale Inspection Software Method for Semiconductor Wafer Analysis

This report describes the non CRADA-protected results of the project performed between Nova Measuring Systems, Ltd., and the Oak Ridge National Laboratory to test and prototype defect signature analysis method for potential incorporation into an in-situ wafer inspection microscope. ORNL's role in this activity was to collaborate with Nova on the analysis and software side of the effort, wile Nova's role was to build the physical microscope and provide data to ORNL for test and evaluation. The objective of this project was to adapt and integrate ORNL's SSA and ADC methods and technologies in the Nova imaging environment. ORNL accomplished this objective by modifying the existing SSA technology for use as a wide-area signature analyzer/classifier on the Nova macro inspection tool (whole-wafer analysis). During this effort ORNL also developed a strategy and methodology for integrating and presenting the results of SSA/ADC analysis to the tool operator and/or data management system (DMS) used by the semiconductor manufacturer (i.e., the end-user).
Date: May 22, 2003
Creator: Tobin, K.W.
Object Type: Report
System: The UNT Digital Library
Weldability of High Alloys (open access)

Weldability of High Alloys

The purpose of this study was to investigate the effect of silicon and iron on the weldability of HAYNES HR-160{reg_sign} alloy. HR-I60 alloy is a solid solution strengthened Ni-Co-Cr-Si alloy. The alloy is designed to resist corrosion in sulfidizing and other aggressive high temperature environments. Silicon is added ({approx}2.75%) to promote the formation of a protective oxide scale in environments with low oxygen activity. HR-160 alloy has found applications in waste incinerators, calciners, pulp and paper recovery boilers, coal gasification systems, and fluidized bed combustion systems. HR-160 alloy has been successfully used in a wide range of welded applications. However, the alloy can be susceptible to solidification cracking under conditions of severe restraint. A previous study by DuPont, et al. [1] showed that silicon promoted solidification cracking in the commercial alloy. In earlier work conducted at Haynes, and also from published work by DuPont et al., it was recognized that silicon segregates to the terminal liquid, creating low melting point liquid films on solidification grain boundaries. Solidification cracking has been encountered when using the alloy as a weld overlay on steel, and when joining HR-160 plate in a thickness greater than19 millimeters (0.75 inches) with matching filler metal. The effect …
Date: January 22, 2003
Creator: Maroef, I
Object Type: Report
System: The UNT Digital Library
THE EFFECT OF INTERSTITIAL N ON GRAIN BOUNDARY COHESIVE STRENGTH IN Fe (open access)

THE EFFECT OF INTERSTITIAL N ON GRAIN BOUNDARY COHESIVE STRENGTH IN Fe

Increased nitrogen levels have been correlated with decreased ductility and elevated ductile-to-brittle transition temperature in pressure vessel steels [1]. However, the exact role played by nitrogen in the embrittlement of steels remains unclear. Miller and Burke have reported atom probe ion microscopy findings from neutron-irradiated low-alloy pressure vessel steel showing the presence of a 1 to 2 ruonolayer thick film of Mo, N, and C at prior austenitic grain boundaries (GB's) [2], suggesting a role for nitrogen as an intergranular embrittler. It is of interest for the development of mitigation strategies whether nitrogen must combine with other impurities to form nitride precipitates in order to exert an embrittling effect. Briant et al [1] have associated the embrittling effect of N in steels exclusively with intergranular nitride formation. This association suggests that high nitrogen levels may be acceptable if nitride precipitation at grain boundaries is suppressed. To address whether precipitate formation is indeed essential to the N embrittlement process in pressure vessel steel, a computational study was undertaken to ascertain whether the presence of interstitial nitrogen alone could embrittle an Fe GB. If so, nitrogen in any form must be kept completely away from the grain boundaries, if not out of …
Date: September 22, 2003
Creator: Miyoung, Kim; Gellar, Clint B. & Freeman, A. F.
Object Type: Report
System: The UNT Digital Library
Quantitative Assessment of Distributed Energy Resource Benefits (open access)

Quantitative Assessment of Distributed Energy Resource Benefits

Distributed energy resources (DER) offer many benefits, some of which are readily quantified. Other benefits, however, are less easily quantifiable because they may require site-specific information about the DER project or analysis of the electrical system to which the DER is connected. The purpose of this study is to provide analytical insight into several of the more difficult calculations, using the PJM power pool as an example. This power pool contains most of Pennsylvania, New Jersey, Maryland, and Delaware. The techniques used here could be applied elsewhere, and the insights from this work may encourage various stakeholders to more actively pursue DER markets or to reduce obstacles that prevent the full realization of its benefits. This report describes methodologies used to quantify each of the benefits listed in Table ES-1. These methodologies include bulk power pool analyses, regional and national marginal cost evaluations, as well as a more traditional cost-benefit approach for DER owners. The methodologies cannot however determine which stakeholder will receive the benefits; that must be determined by regulators and legislators, and can vary from one location to another.
Date: May 22, 2003
Creator: Hadley, S. W.; Van Dyke, J. W.; Poore, W. P., III & Stovall, T. K.
Object Type: Report
System: The UNT Digital Library
Facilities for Development of Modified Nitride-Based Fuel Pellets (open access)

Facilities for Development of Modified Nitride-Based Fuel Pellets

Facilities to support development of modified nitride-based reactor fuel pellets have been activated and are now in operation at Lawrence Livermore National Laboratory. These facilities provide the controls and monitored laboratory conditions required to produce, evaluate, and verify quality of the nitride-based product required for this fuel application. By preserving the high melting point, high thermal conductivity, and high actinide density properties of nitride fuel while enhancing stoichiometry, density, and grain structure, and by applying inert matrix (ZrN) and neutron absorbing (HfN) additives for improved stability and burn-up characteristics, the requirements for a long-life fuel to support sealed core reactor applications may be met. This paper discusses requirements for producing the modified nitride powders for sintering of fuel pellets, translation of these requirements into facility specifications, and implementation of these specifications as facility capabilities.
Date: October 22, 2003
Creator: Meier, T.; Ebbinghaus, B. & Choi, J.
Object Type: Article
System: The UNT Digital Library
Hohlraum-Driven Ignition-Like Double-Shell Implosion Experiments on Omega: Analysis and Interpretation (open access)

Hohlraum-Driven Ignition-Like Double-Shell Implosion Experiments on Omega: Analysis and Interpretation

An experimental campaign to study hohlraum-driven ignition-like double-shell target performance using the Omega laser facility has begun. These targets are intended to incorporate as many ignition-like properties of the proposed National Ignition Facility (NIF) double-shell ignition design [1,2] as possible, given the energy constraints of the Omega laser. In particular, this latest generation of Omega double-shells is nominally predicted to produce over 99% of the (clean) DD neutron yield from the compressional or stagnation phase of the implosion as required in the NIF ignition design. By contrast, previous double-shell experience on Omega [3] was restricted to cases where a significant fraction of the observed neutron yield was produced during the earlier shock convergence phase where the effects of mix are deemed negligibly small. These new targets are specifically designed to have optimized fall-line behavior for mitigating the effects of pusher-fuel mix after deceleration onset and, thereby, providing maximum neutron yield from the stagnation phase. Experimental results from this recent Omega ignition-like double-shell implosion campaign show favorable agreement with two-dimensional integrated hohlraum simulation studies when enhanced (gold) hohlraum M-band (2-5 keV) radiation is included at a level consistent with observations.
Date: August 22, 2003
Creator: Amendt, P.; Robey, H. F.; Park, H. S.; Tipton, R. E.; Turner, R. E.; Milovich, J. et al.
Object Type: Article
System: The UNT Digital Library
Evaluation of the Relative Importance of Parameters Influencing Perforation Cleanup (open access)

Evaluation of the Relative Importance of Parameters Influencing Perforation Cleanup

Completion of cased and cemented wells by shaped-charge perforation results in damage to the formation, which can significantly reduce well productivity. Typically, underbalanced conditions are imposed during perforation in an effort to remove damaged rock and shaped-charge debris from the perforation tunnel. Immediately after the shaped-charge jet penetrates the formation, there is a transient surge of fluid from the formation through the perforation and into the well bore. Experimental evidence suggests that it is this transient pressure surge that leads to the removal of damaged rock and charge debris leaving an open perforation tunnel. We have developed a two-stage computational model to simulate the perforation process and subsequent pressure surge and debris removal. The first stage of the model couples a hydrocode with a model of stress-induced permeability evolution to calculate damage to the formation and the resulting permeability field. The second stage simulates the non-Darcy, transient fluid flow from the formation and removes damaged rock and charge debris from the perforation tunnel. We compare the model to a series of API RP43 section 4 flow tests and explore the influence of fluid viscosity and rock strength on the final perforation geometry and permeability.
Date: October 22, 2003
Creator: Detwiler, R L; Morris, J P; Karacan, C O; Halleck, P M & Hardesty, J
Object Type: Article
System: The UNT Digital Library
General MoM Solutions for Large Arrays (open access)

General MoM Solutions for Large Arrays

This paper focuses on a numerical procedure that addresses the difficulties of dealing with large, finite arrays while preserving the generality and robustness of full-wave methods. We present a fast method based on approximating interactions between sufficiently separated array elements via a relatively coarse interpolation of the Green's function on a uniform grid commensurate with the array's periodicity. The interaction between the basis and testing functions is reduced to a three-stage process. The first stage is a projection of standard (e.g., RWG) subdomain bases onto a set of interpolation functions that interpolate the Green's function on the array face. This projection, which is used in a matrix/vector product for each array cell in an iterative solution process, need only be carried out once for a single cell and results in a low-rank matrix. An intermediate stage matrix/vector product computation involving the uniformly sampled Green's function is of convolutional form in the lateral (transverse) directions so that a 2D FFT may be used. The final stage is a third matrix/vector product computation involving a matrix resulting from projecting testing functions onto the Green's function interpolation functions; the low-rank matrix is either identical to (using Galerkin's method) or similar to that for …
Date: July 22, 2003
Creator: Fasenfest, B; Capolino, F; Wilton, D R; Jackson, D R & Champagne, N
Object Type: Article
System: The UNT Digital Library
Density-functional calculations of a, b, g, d, dp, and e plutonium (open access)

Density-functional calculations of a, b, g, d, dp, and e plutonium

Total energies for the six known polymorphs of plutonium metal have been calculated within spin and orbital polarized density-functional theory as a function of lattice constant. Theoretical equilibrium volumes and bulk moduli correspond well with experimental data and the calculated total energies are consistent with the known phase diagram of Pu. It is shown that a preference for formation of magnetic moments, increasing through the {alpha} {yields} {beta} {yields} {gamma} phases, explain their position in the ambient pressure phase diagram and their anomalous variation of atomic density. A simple model is presented that establishes a relationship between atomic density, crystal symmetry, and magnetic moments which is universally valid for all Pu phases.
Date: October 22, 2003
Creator: Soderlind, P & Sadigh, B
Object Type: Article
System: The UNT Digital Library
Numerical Simulations of Shock-Induced Mixing and Combustion (open access)

Numerical Simulations of Shock-Induced Mixing and Combustion

In this paper we use numerical simulation to investigate shock-induced ignition and combustion of a hydrocarbon gas. The focus of this paper is on quantifying the effect of fidelity in the chemical kinetics on the overall solution. We model the system using the compressible Navier Stokes equations for a reacting mixture. These equations express conservation of species mass, momentum, total energy.
Date: April 22, 2003
Creator: Bell, J B; Day, M & Kuhl, A L
Object Type: Article
System: The UNT Digital Library
Yakima Habitat Improvement Project Master Plan, Technical Report 2003. (open access)

Yakima Habitat Improvement Project Master Plan, Technical Report 2003.

The Yakima Urban Growth Area (UGA) is a developing and growing urban area in south-central Washington. Despite increased development, the Yakima River and its tributaries within the UGA continue to support threatened populations of summer steelhead and bull trout as well as a variety of non-listed salmonid species. In order to provide for the maintenance and recovery of these species, while successfully planning for the continued growth and development within the UGA, the City of Yakima has undertaken the Yakima Habitat Improvement Project. The overall goal of the project is to maintain, preserve, and restore functioning fish and wildlife habitat within and immediately surrounding the Yakima UGA over the long term. Acquisition and protection of the fish and wildlife habitat associated with key properties in the UGA will prevent future subdivision along riparian corridors, reduce further degradation or removal of riparian habitat, and maintain or enhance the long term condition of aquatic habitat. By placing these properties in long-term protection, the threat of development from continued growth in the urban area will be removed. To most effectively implement the multi-year habitat acquisition and protection effort, the City has developed this Master Plan. The Master Plan provides the structure and guidance …
Date: April 22, 2003
Creator: Golder Associates, Inc.
Object Type: Report
System: The UNT Digital Library
Analytical and Numerical Ray Tracing of X-Ray Lasers (open access)

Analytical and Numerical Ray Tracing of X-Ray Lasers

Soft x-ray lasers in 10-30nm range are now routinely produced in hot plasmas generated either by a laser from a solid target or by an electrical discharge in a capillary. Such an x-ray laser is a convenient tool for future applications, such as probing dense plasmas of interest for fusion experiments. Their short wavelength enables plasma diagnosis beyond the capabilities of optical lasers, because the high critical plasma density ({approx}{lambda}{sup 2}) limits the optical beam propagation. In our paper, we present analytical and numerical ray tracing of an x-ray laser in dense amplifying plasmas. A general analytical formula for a beam propagation has been developed for a gradient plasma. The simplified analytical formulaes enable better understanding of processes involved. They also simplify optimization of the beam propagation and ''mapping'' the parameter space for further studies by numerical codes. We discuss implications for a transient x-ray laser that is produced from a slab target by a (sub-)picosecond laser pulse.
Date: December 22, 2003
Creator: Kuba, J; Shlyaptsev, V N; Benredjem, D & Moller, C
Object Type: Article
System: The UNT Digital Library
COLD TEST LOOP INTEGRATED TEST LOOP RESULTS (open access)

COLD TEST LOOP INTEGRATED TEST LOOP RESULTS

A testing facility (Cold Test Loop) was constructed and operated to demonstrate the efficacy of the Accelerated Waste Retrieval (AWR) Project's planned sluicing approach to the remediation of Silos 1 and 2 at the Fernald Environmental Management Project near Cincinnati, Ohio. The two silos contain almost 10,000 tons of radium-bearing low-level waste, which consists primarily of solids of raffinates from processing performed on ores from the Democratic Republic of Congo (commonly referred to as ''Belgium Congo ores'') for the recovery of uranium. These silos are 80 ft in diameter, 36 ft high to the center of the dome, and 26.75 ft to the top of the vertical side walls. The test facility contained two test systems, each designed for a specific purpose. The first system, the Integrated Test Loop (ITL), a near-full-scale plant including the actual equipment to be installed at the Fernald Site, was designed to demonstrate the sluicing operation and confirm the selection of a slurry pump, the optimal sluicing nozzle operation, and the preliminary design material balance. The second system, the Component Test Loop (CTL), was designed to evaluate many of the key individual components of the waste retrieval system over an extended run. The major results …
Date: October 22, 2003
Creator: Abraham, TJ
Object Type: Report
System: The UNT Digital Library
MICROSTRUCTURE IN ADIABATIC SHEAR BANDS IN A PEARLITIC ULTRAHIGH CARBON STEEL (open access)

MICROSTRUCTURE IN ADIABATIC SHEAR BANDS IN A PEARLITIC ULTRAHIGH CARBON STEEL

Adiabatic shear bands, obtained in compression deformation at a strain rate of 4000 s{sup -1}, in a pearlitic 1.3%C steel, were investigated. Shear-bands initiated at 55% compression deformation with the width of the band equal to 14 {micro}m. Nano-indentor hardness of the shear band was 11.5 GPa in contrast to the initial matrix hardness of 3.5 GPa. The high strength of the shear band is attributed to its creation from two sequential events. First, large strain deformation, at a high strain rate, accompanied by adiabatic heating, led to phase transformation to austenite. Second, retransformation upon rapid cooling occurred by a divorced eutectoid transformation. The result is a predicted microstructure consisting of nano-size carbide particles within a matrix of fine ferrite grains. It is proposed that the divorced eutectoid transformation occurs in iron-carbon steels during high rate deformation in ball milling, ball drop tests and in commercial wire drawing.
Date: September 22, 2003
Creator: Syn, C K; Lesuer, D R & Sherby, O D
Object Type: Article
System: The UNT Digital Library
High temperature degradation by erosion-corrosion in bubbling fluidized bed combustors (open access)

High temperature degradation by erosion-corrosion in bubbling fluidized bed combustors

Heat-exchanger tubes in fluidized bed combustors (FBCs) often suffer material loss due to combined corrosion and erosion. Most severe damage is believed to be caused by the impact of dense packets of bed material on the lower parts of the tubes. In order to understand this phenomenon, a unique laboratory test rig at Berkeley was designed to simulate the particle hammering interactions between in-bed particles and tubes in bubbling fluidized bed combustors. In this design, a rod shaped specimen is actuated a short distance within a partially fluidized bed. The downward specimen motion is controlled to produce similar frequencies, velocities and impact forces as those experienced by the impacting particle aggregates in practical systems. Room temperature studies have shown that the degradation mechanism is a three-body abrasion process. This paper describes the characteristics of this test rig, reviews results at elevated temperatures and compares them to field experience. At higher temperatures, deposits of the bed material on tube surfaces can act as a protective layer. The deposition depended strongly on the type of bed material, the degree of tube surface oxidation and the tube and bed temperatures. With HCl present in the bed, wastage was increased due to enhanced oxidation …
Date: April 22, 2003
Creator: Hou, Peggy Y.; MacAdam, S.; Niu, Y. & Stringer, J.
Object Type: Article
System: The UNT Digital Library
Growth and characterization of In{sub x}Ga{sub 1-x}N MQW using a novel method of temperature gradient OMVPE (open access)

Growth and characterization of In{sub x}Ga{sub 1-x}N MQW using a novel method of temperature gradient OMVPE

None
Date: July 22, 2003
Creator: Johnson, M.C.; Jorgensen, R.J.; Wu, J.; Shan, W. & Bourret-Courchesne, E.
Object Type: Article
System: The UNT Digital Library
Airfare and Catering Costs in Support of Panelists Attendance at Panel (open access)

Airfare and Catering Costs in Support of Panelists Attendance at Panel

Panelist attendance at the National Science Foundation Plasma Panel.
Date: December 22, 2003
Creator: McKnight, R.
Object Type: Report
System: The UNT Digital Library
Chemically Vapor Deposited Yttria-Stabilized Zirconia (YSZ) for Thermal and Environmental Barrier Coating (open access)

Chemically Vapor Deposited Yttria-Stabilized Zirconia (YSZ) for Thermal and Environmental Barrier Coating

Yttria-stabilized zirconia (YSZ) is used as a thermal barrier coating (TBC) to protect super-alloy blades such as Mar-M247 or Rene-N5 during engine operation. The current method for YSZ fabrication for TBC applications is by air-plasma spraying (APS) or electron beam physical vapor deposition (EB-PVD) (Haynes 1997). APS gives reasonable deposition rates, but has a limited life and aging effects due to its porous and lamellar structure. The EB-PVD coatings are more stable and can accommodate thermomechanical stresses due to their characteristic strain-tolerant, columnar microstructure. EB-PVD, however, is primarily line-of-sight, which often leaves ''hidden areas'' uncoated, has low throughput, and has high capital cost. The process of metal-organic chemical vapor deposition (MOCVD) is investigated here as an economical alternative to EB-PVD and APS, with the potential for better overall coverage as well as the ability to produce thick (100-250 {micro}m), strain-tolerant, columnar coatings. MOCVD of YSZ involves the use of zirconium and yttrium organometallic precursors reacting with an oxygen source. Previous researchers have used diketonate or chloride precursors and oxygen (Wahl et al. 2001a, Wahl et al. 2001b, Yamane and Harai 1989). These precursors have low transport rates due to their low carrier solvent solubility (Varanasi et al. 2003). Solvated zirconium …
Date: April 22, 2003
Creator: Varanasi, V. G.; Besmann, T. M.; Lothian, J. L.; Xu, W. & Starr, T. L.
Object Type: Article
System: The UNT Digital Library
Simultaneous Energy Savings and IEQ Improvements in Relocatable Classrooms (open access)

Simultaneous Energy Savings and IEQ Improvements in Relocatable Classrooms

Relocatable classrooms (RCs) are commonly used by school districts with changing demographics and enrollment sizes. We designed and constructed four energy-efficient RCs for this study to demonstrate technologies with the potential to simultaneously improve energy efficiency and indoor environmental quality (IEQ). Two were installed at each of two school districts, and energy use and IEQ parameters were monitored during occupancy. Two RCs (one per school) were finished with materials selected for reduced emissions of toxic and odorous volatile organic compounds (VOCs). Each had two HVAC systems, operated on alternate weeks, consisting of a standard heat-pump system and an indirect-direct evaporative cooling (IDEC) system with gas-fired hydronic heating. The IDEC system provides continuous outside air ventilation at {sup 3}15 CFM (7.5 L s-1) person-1, efficient particle filtration while using significantly less energy for cooling. School year long measurements included: carbon dioxide (CO2), particles, VOCs, temperature, humidity, thermal comfort, noise, meteorology, and energy use. IEQ monitoring results indicate that important ventilation-relevant indoor CO2 and health-relevant VOC concentration reductions were achieved while average cooling and heating energy costs were simultaneously reduced by 50 percent and 30 percent, respectively.
Date: May 22, 2003
Creator: Apte, Michael G.; Dibartolomeo, Dennis; Hotchi, Toshi; Hodgson, Alfred T.; Lee, Seung-Min; Liff, Shawna M. et al.
Object Type: Report
System: The UNT Digital Library
Treated LAW Feed Evaporation: Physical and Solubility Determination (U) (open access)

Treated LAW Feed Evaporation: Physical and Solubility Determination (U)

Evaporation is employed in several places in the Waste Treatment Plant pretreatment process to minimize the volume of waste that must be treated in down-stream vitrification processes. Evaporation is the first unit process in pretreatment (Waste Feed Evaporators), applied before LAW vitrification (Treated Feed Evaporator), and concentrates ion exchange eluate (Cs Eluate Evaporator) prior to HLW vitrification. The goal of the Treated Feed Evaporation process is removal of the maximum water content without producing additional insoluble solids. Prior testing of evaporation systems for process feed was completed to support compliance with regulatory permits and to prepare a model of the evaporation system. These tests also indicated a marked tendency for foaming in the WTP evaporators. To date, evaporation testing and modeling have focused on the Treated feed and Cs eluate evaporation systems. This has been the first work performed that investigates evaporation of secondary-waste recycle streams in the Treated LAW Feed Evaporator. Secondary-waste recycles from the LAW off- gas scrubbing system have been the major contributors to the overall Treated Feed Evaporator recycle volume. Experience from Savannah River Site operations suggests that the introduction of silica- laden recycles to an evaporator along with high-sodium treated LAW can significantly increase the …
Date: July 22, 2003
Creator: Josephs, JE.
Object Type: Report
System: The UNT Digital Library
PHASE II CALDERON PROCESS TO PRODUCE DIRECT REDUCED IRON RESEARCH AND DEVELOPMENT PROJECT (open access)

PHASE II CALDERON PROCESS TO PRODUCE DIRECT REDUCED IRON RESEARCH AND DEVELOPMENT PROJECT

This project was initially targeted to the making of coke for blast furnaces by using proprietary technology of Calderon in a phased approach, and Phase I was successfully completed. The project was then re-directed to the making of iron units. In 2000, U.S. Steel teamed up with Calderon for a joint effort which will last 42 months to produce directly reduced iron with the potential of converting it into molten iron or steel consistent with the Roadmap recommendations of 1998 prepared by the Steel Industry in cooperation with the Department of Energy by using iron ore concentrate and coal as raw materials, both materials being appreciably lower in cost than using iron pellets and coke.
Date: October 22, 2003
Creator: Calderon, Albert
Object Type: Report
System: The UNT Digital Library
High Temperature Oxidation Performance of Aluminide Coatings (open access)

High Temperature Oxidation Performance of Aluminide Coatings

In order to determine the potential benefits and limitations of aluminide coatings, coatings made by chemical vapor deposition (CVD) on Fe- and Ni-base alloy substrates are being evaluated in various high-temperature environments. Testing of coatings on representative ferritic (Fe-9Cr-1Mo) and austenitic (type 304L stainless steel) alloys has found that high frequency thermal cycling (1h cycle time) can significantly degrade the coating. Based on comparison with similar specimens with no thermal cycling or a longer cycle time (100h), this degradation was not due to Al loss from the coating but most likely because of the thermal expansion mismatch between the coating and the substrate. Several coated Ni-base alloys were tested in a high pressure (20atm) steam-CO2 environment for the ZEST (zero-emission steam turbine) program. Coated specimens showed less mass loss than the uncoated specimens after 1000h at 900 C and preliminary characterization examined the post-test coating structure and extent of attack.
Date: April 22, 2003
Creator: Pint, B. A.; Zhang, Y.; Haynes, J. A. & Wright, I. G.
Object Type: Article
System: The UNT Digital Library
MODELING OF CHEMICAL VAPOR DEPOSITED ZIRCONIA FOR THERMAL BARRIER AND ENVIRONMENTAL BARRIER COATINGS (open access)

MODELING OF CHEMICAL VAPOR DEPOSITED ZIRCONIA FOR THERMAL BARRIER AND ENVIRONMENTAL BARRIER COATINGS

Thermal and environmental barrier coatings are important components of current and future energy systems. Such coatings--applied to hot, metallic surfaces in combustors, heat exchanger and turbines--increase the allowable operating temperature and increase the efficiency of the energy system. Because of its low thermal conductivity and high thermal expansion yttria-stabilized zirconia (YSZ) is the material of choice for protection of structural components in many high temperature applications. Current coating application methods have their drawbacks, however. Air plasma spray (APS) is a relatively low-cost process and is suitable for large and relatively complex shapes. It is difficult to produce uniform, relatively thin coatings with this process, however, and the coatings do not exhibit the columnar microstructure that is needed for reliable, long-term performance. The electron-beam physical vapor deposition (EB-PVD) process does produce the desirable microstructure, however, the capital cost of these systems is very high and the line-of-sight nature of the process limits coating uniformity and the ability to coat large and complex shapes. The chemical vapor deposition (CVD) process also produces the desirable columnar microstructure and--under proper conditions--can produce uniform coatings over complex shapes. The overall goal of this project--a joint effort of the University of Louisville and Oak Ridge National …
Date: April 22, 2003
Creator: Starr, T.L; Xu, W. & Qiu, S.
Object Type: Article
System: The UNT Digital Library
RESERVOIR CHARACTERIZATION & 3D MODELS OF MT. SIMON GAS STORAGE FIELDS IN THE ILLINOIS BASIN (open access)

RESERVOIR CHARACTERIZATION & 3D MODELS OF MT. SIMON GAS STORAGE FIELDS IN THE ILLINOIS BASIN

None
Date: September 22, 2003
Creator: Morse, David G. & Leetaru, Hannes E.
Object Type: Report
System: The UNT Digital Library