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Sample records for westinghouse thermal barrier

  1. Westinghouse thermal barrier coatings development

    Energy Technology Data Exchange (ETDEWEB)

    Goedjen, J.G.; Wagner, G. [Westinghouse Electric Corp., Orlando, FL (United States)

    1995-10-01

    Westinghouse, in conjunction with the Department of Energy and Oak Ridge National Laboratory, has embarked upon a program for the development of advanced thermal barrier coatings for industrial gas turbines. Development of thermal barrier coatings (TBC`s) for industrial gas turbines has relied heavily on the transfer of technology from the aerospace industry. Significant differences in the time/temperature/stress duty cycles exist between these two coating applications. Coating systems which perform well in aerospace applications may not been optimized to meet power generation performance requirements. This program will focus on development of TBC`s to meet the specific needs of power generation applications. The program is directed at developing a state-of-the-art coating system with a minimum coating life of 25,000 hours at service temperatures required to meet increasing operating efficiency goals. Westinghouse has assembled a team of university and industry leaders to accomplish this goal. Westinghouse will coordinate the efforts of all program participants. Chromalloy Turbine Technologies, Inc. and Sermatech International, Inc. will be responsible for bond coat and TBC deposition technology. Praxair Specialty Powders, Inc. will be responsible for the fabrication of all bond coat and ceramic powders for the program. Southwest Research Institute will head the life prediction modelling effort; they will also be involved in coordinating nondestructive evaluation (NDE) efforts. Process modelling will be provided by the University of Arizona.

  2. Thermal barriers for compartments

    Energy Technology Data Exchange (ETDEWEB)

    Kreutzer, Cory J.; Lustbader, Jason A.

    2017-10-17

    An aspect of the present disclosure is a thermal barrier that includes a core layer having a first surface, a second surface, and a first edge, and a first outer layer that includes a third surface and a second edge, where the third surface substantially contacts the first surface, the core layer is configured to minimize conductive heat transfer through the barrier, and the first outer layer is configured to maximize reflection of light away from the barrier.

  3. Overview of Westinghouse`s Advanced Turbine Systems Program

    Energy Technology Data Exchange (ETDEWEB)

    Bannister, R.L.; Bevc, F.P.; Diakunchak, I.S.; Huber, D.J. [Westinghouse Electric Corp., Orlando, FL (United States)

    1995-10-01

    Westinghouse`s experience with land based gas turbines started in 1945 with the development of a 2000 hp gas turbine-generator set that consisted of a single reduction gear, compressor, 12 combustors and turbine. A thermal efficiency of 18% was obtained. By 1954, Westinghouse had developed a 15 MW unit (with a regenerator and intercooler) that was designed for a full-load simple cycle efficiency of 29%. As the initial step in the Advanced Turbine Systems (ATS) program, Westinghouse has already developed a 230 MW gas turbine that has a simple cycle efficiency of 38.5% without the use of regeneration and intercooler concepts. In 1967, Westinghouse developed its first gas turbine combined cycle, a synergistic combination of the Brayton and the Rankine cycles. In a combined cycle the heat rejected by the higher temperature topping cycle is recovered in the lower temperature bottoming cycle to produce additional power from the energy initially released by the fuel. In this first Westinghouse combined cycle, a 1450{degrees}F burner outlet temperature gas turbine, rated at 25 MW, supplied exhaust heat which was used in a boiler to furnish steam to drive an 85 MW steam turbine. This plant achieved an annual average efficiency of 39.6%.

  4. Flexible pile thermal barrier insulator

    Science.gov (United States)

    Anderson, G. E.; Fell, D. M.; Tesinsky, J. S. (Inventor)

    1978-01-01

    A flexible pile thermal barrier insulator included a plurality of upstanding pile yarns. A generally planar backing section supported the upstanding pile yarns. The backing section included a plurality of filler yarns forming a mesh in a first direction. A plurality of warp yarns were looped around said filler yarns and pile yarns in the backing section and formed a mesh in a second direction. A binder prevented separation of the yarns in the backing section.

  5. Pratt & Whitney thermal barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Bornstein, N. [United Technologies Research Center, East Hartford, CT (United States); Marcin, J. [Pratt & Whitney Aircraft Co., East Hartford, CT (United States)

    1995-10-01

    The objective of the Advanced Turbine Systems (ATS) Program is to develop ultra-high efficient, environmentally superior, and cost competitive gas turbine systems. The operating profiles of these industrial gas turbines are long, less cyclic with fewer transients-compared with those for aircraft gas turbine engines. Therefore, creep rather than thermal fatigue, becomes primary life-limiting for hot section components. Thermal barrier coatings (TBCs) will be used to achieve the objectives of the program. TBCs allow surface temperatures to increase without compromising the structural properties of the alloy. TBCs typically consist of a ceramic insulating layer, deposited onto the substrate with an intervening metallic layer, which imparts oxidation protection to the substrate and provides a surface to which the ceramic layer can adhere.

  6. Rocket Motor Joint Construction Including Thermal Barrier

    Science.gov (United States)

    Steinetz, Bruce M. (Inventor); Dunlap, Patrick H., Jr. (Inventor)

    2002-01-01

    A thermal barrier for extremely high temperature applications consists of a carbon fiber core and one or more layers of braided carbon fibers surrounding the core. The thermal barrier is preferably a large diameter ring, having a relatively small cross-section. The thermal barrier is particularly suited for use as part of a joint structure in solid rocket motor casings to protect low temperature elements such as the primary and secondary elastomeric O-ring seals therein from high temperature gases of the rocket motor. The thermal barrier exhibits adequate porosity to allow pressure to reach the radially outward disposed O-ring seals allowing them to seat and perform the primary sealing function. The thermal barrier is disposed in a cavity or groove in the casing joint, between the hot propulsion gases interior of the rocket motor and primary and secondary O-ring seals. The characteristics of the thermal barrier may be enhanced in different applications by the inclusion of certain compounds in the casing joint, by the inclusion of RTV sealant or similar materials at the site of the thermal barrier, and/or by the incorporation of a metal core or plurality of metal braids within the carbon braid in the thermal barrier structure.

  7. Thermal barrier coating system having improved adhesion

    Science.gov (United States)

    Bill, R. C.; Sovey, J. S. (Inventor)

    1982-01-01

    The adherence between a ceramic thermal barrier coating and a metal bond coating is improved by ion sputtering a ceramic film on the bond cost. A ceramic thermal barrier coating is then plasma-sprayed onto this primer film. This improves the integrity and strength of the interface between the plasma-sprayed ceramic layer and metallic bond coat which insures stronger adherence between the metal and the ceramic.

  8. Reusable Thermal Barrier for Insulation Gaps

    Science.gov (United States)

    Saladee, C. E.

    1985-01-01

    Filler composed of resilient, heat-resistant materials. Thermal barrier nestles snugly in gap between two tiles with minimal protrusion beyond faces of surrounding tiles. When removed from gap, barrier springs back to nearly original shape. Developed for filling spaces between tiles on Space Shuttle, also used in furnaces and kilns.

  9. Lifetime Modeling of Thermal Barrier Coatings

    NARCIS (Netherlands)

    Hille, T.S.

    2009-01-01

    Thermal barrier coatings (TBCs) are applied in gas turbines to enhance their thermal efficiency by isolating the metallic components from the aggressive hot gas. TBC lifetime is limited by damage processes originating at internal interfaces, which may ultimately lead to delamination and spallation.

  10. The Effect of Core Configuration on Thermal Barrier Thermal Performance

    Science.gov (United States)

    DeMange, Jeffrey J.; Bott, Robert H.; Druesedow, Anne S.

    2015-01-01

    Thermal barriers and seals are integral components in the thermal protection systems (TPS) of nearly all aerospace vehicles. They are used to minimize heat transfer through interfaces and gaps and protect underlying temperature-sensitive components. The core insulation has a significant impact on both the thermal and mechanical properties of compliant thermal barriers. Proper selection of an appropriate core configuration to mitigate conductive, convective and radiative heat transfer through the thermal barrier is challenging. Additionally, optimization of the thermal barrier for thermal performance may have counteracting effects on mechanical performance. Experimental evaluations have been conducted to better understand the effect of insulation density on permeability and leakage performance, which can significantly impact the resistance to convective heat transfer. The effect of core density on mechanical performance was also previously investigated and will be reviewed. Simple thermal models were also developed to determine the impact of various core parameters on downstream temperatures. An extended understanding of these factors can improve the ability to design and implement these critical TPS components.

  11. Anisotropic Thermal Diffusivities of Plasma-Sprayed Thermal Barrier Coatings

    Science.gov (United States)

    Akoshima, Megumi; Takahashi, Satoru

    2017-09-01

    Thermal barrier coatings (TBCs) are used to shield the blades of gas turbines from heat and wear. There is a pressing need to evaluate the thermal conductivity of TBCs in the thermal design of advanced gas turbines with high energy efficiency. These TBCs consist of a ceramic-based top coat and a bond coat on a superalloy substrate. Usually, the focus is on the thermal conductivity in the thickness direction of the TBC because heat tends to diffuse from the surface of the top coat to the substrate. However, the in-plane thermal conductivity is also important in the thermal design of gas turbines because the temperature distribution within the turbine cannot be ignored. Accordingly, a method is developed in this study for measuring the in-plane thermal diffusivity of the top coat. Yttria-stabilized zirconia top coats are prepared by thermal spraying under different conditions. The in-plane and cross-plane thermal diffusivities of the top coats are measured by the flash method to investigate the anisotropy of thermal conduction in a TBC. It is found that the in-plane thermal diffusivity is higher than the cross-plane one for each top coat and that the top coats have significantly anisotropic thermal diffusivity. The cross-sectional and in-plane microstructures of the top coats are observed, from which their porosities are evaluated. The thermal diffusivity and its anisotropy are discussed in detail in relation to microstructure and porosity.

  12. Nuclear reactor vessel fuel thermal insulating barrier

    Science.gov (United States)

    Keegan, C. Patrick; Scobel, James H.; Wright, Richard F.

    2013-03-19

    The reactor vessel of a nuclear reactor installation which is suspended from the cold leg nozzles in a reactor cavity is provided with a lower thermal insulating barrier spaced from the reactor vessel that has a hemispherical lower section that increases in volume from the center line of the reactor to the outer extent of the diameter of the thermal insulating barrier and smoothly transitions up the side walls of the vessel. The space between the thermal insulating harrier and the reactor vessel forms a chamber which can be flooded with cooling water through passive valving to directly cool the reactor vessel in the event of a severe accident. The passive inlet valve for the cooling water includes a buoyant door that is normally maintained sealed under its own weight and floats open when the cavity is Hooded. Passively opening steam vents are also provided.

  13. Delamination-Indicating Thermal Barrier Coatings

    Science.gov (United States)

    Eldridge, Jeffrey I.

    2007-01-01

    The risk of premature failure of thermal barrier coatings (TBCs), typically composed of yttria-stabilized zirconia (YSZ), compromises the reliability of TBCs used to provide thermal protection for turbine engine components. Unfortunately, TBC delamination proceeds well beneath the TBC surface and cannot be monitored by visible inspection. Nondestructive diagnostic tools that could reliably probe the subsurface damage state of TBCs would alleviate the risk of TBC premature failure by indicating when the TBC needs to be replaced before the level of TBC damage threatens engine performance or safety. To meet this need, a new coating design for thermal barrier coatings (TBCs) that are self-indicating for delamination has been successfully implemented by incorporating a europium-doped luminescent sublayer at the base of a TBC composed of YSZ. The luminescent sublayer has the same YSZ composition as the rest of the TBC except for the addition of low-level europium doping and therefore does not alter TBC performance.

  14. Development of metal based thermal barrier coatings

    Science.gov (United States)

    Shin, Dong-Il

    In this work, metal-based thermal barrier coatings (MBTBCs) have been produced, using high frequency induction plasma spraying (IPS) of iron-based nanostructured alloy powders. Important advances have been made over recent years to the development of ceramic-based thermal barrier coatings (TBCs) for internal combustion engines application, but they are not yet applied in mass production situations. Besides the important economic considerations, the reliability of ceramic: TBCs is also an issue, being associated with the difficulty of predicting their "in-service" lifetime. Through engineering of the nano/amorphous structure of MBTBCs, their thermal conductivity can be made as low as those of ceramic-based TBCs, with reduced mean free paths of the electrons/phonons scattering. In this work, nano/amorphous structured coatings were deposited by IPS using the following spray parameters: spraying distance (210 ˜ 270 mm), plasma gas composition (Ar/N2), IPS torch power (24kW), and powder feed-rate (16g/min.). The structure and properties of the deposited layers were characterized through SEM (Scanning Electron Microscopy) observations. The thermal diffusivity (alpha) properties of the MBTBCs were measured using a laser flash method. Density (rho) and specific heat (Cp) of the MBTBCs were also measured, and their thermal conductivity (k) calculated (k =alpharhoCp). The thermal conductivity of MBTBCs was found to be as low as 1.99 W/m/K. The heat treatment study showed that crystal structure changes, and grain size growth from a few nanometers to tenth of nanometers occurred at 550°C under static exposure conditions. Thermal expansion coefficient (TEC) of MBTBCs was 13E-6/K, which is close to the TEC of cast iron and thus, closer to the TEC values of aluminium alloys than are conventional TBCs. Fracture toughness of MBTBCs has also been assessed by use of Vickers hardness tests, with a 500 g load for 15 s, and the results show that there are no measurable crack

  15. Combination Thermal Barrier And Wear Coatings For Engines

    Science.gov (United States)

    Weingart, Mike; Moller, Paul

    1995-01-01

    Thermal-barrier layers covered with self-lubricating surface layers. Zirconia thermal-barrier coat applied to surface of combustion chamber in engine by plasma-arc spraying. Then PS-200 plasma-arc sprayed onto zirconia. Self-lubricating coat prevents sliding contact between thermal barrier and piston ring, effectively preventing both wear and production of additional heat via friction. Other combinations of thermal-barrier and self-lubricating, wear-resistant coating materials used as long as two materials adhere to each other, applied by use of similar or compatible processes, have similar coefficients of thermal expansion, sufficiently strong at high temperatures, and affordable.

  16. Evaluation of Erosion Resistance of Advanced Turbine Thermal Barrier Coatings

    Science.gov (United States)

    Zhu, Dongming; Kuczmarski, Maria A.; Miller, Robert A.; Cuy, Michael D.

    2007-01-01

    The erosion resistant turbine thermal barrier coating system is critical to aircraft engine performance and durability. By demonstrating advanced turbine material testing capabilities, we will be able to facilitate the critical turbine coating and subcomponent development and help establish advanced erosion-resistant turbine airfoil thermal barrier coatings design tools. The objective of this work is to determine erosion resistance of advanced thermal barrier coating systems under simulated engine erosion and/or thermal gradient environments, validating advanced turbine airfoil thermal barrier coating systems based on nano-tetragonal phase toughening design approaches.

  17. Combustion chemical vapor desposited coatings for thermal barrier coating systems

    Energy Technology Data Exchange (ETDEWEB)

    Hampikian, J.M.; Carter, W.B. [Georgia Institute of Technology, Atlanta, GA (United States)

    1995-10-01

    The new deposition process, combustion chemical vapor deposition, shows a great deal of promise in the area of thermal barrier coating systems. This technique produces dense, adherent coatings, and does not require a reaction chamber. Coatings can therefore be applied in the open atmosphere. The process is potentially suitable for producing high quality CVD coatings for use as interlayers between the bond coat and thermal barrier coating, and/or as overlayers, on top of thermal barrier coatings.

  18. Thermal barrier coatings for gas turbine and diesel engines

    Science.gov (United States)

    Miller, Robert A.; Brindley, William J.; Bailey, M. Murray

    1989-01-01

    The present state of development of thin thermal barrier coatings for aircraft gas turbine engines and thick thermal barrier coatings for truck diesel engines is assessed. Although current thermal barrier coatings are flying in certain gas turbine engines, additional advances will be needed for future engines. Thick thermal barrier coatings for truck diesel engines have advanced to the point where they are being seriously considered for the next generation of engine. Since coatings for truck engines is a young field of inquiry, continued research and development efforts will be required to help bring this technology to commercialization.

  19. Thermal barrier coatings for heat engine components

    Science.gov (United States)

    Levine, S. R.; Miller, R. A.; Hodge, P. E.

    1980-01-01

    A comprehensive NASA-Lewis program of coating development for aircraft gas turbine blades and vanes is presented. Improved ceramic layer compositions are investigated, along the MCrAlY bond films and the methods of uniform deposition of the coatings; the thermomechanical and fuel impurity tolerance limits of the coatings are being studied. Materials include the ZrO2-Y2O3/NiCrAlY system; the effects of the bond coat and zirconia composition on coating life and Mach 1 burner rig test results are discussed. It is concluded that Diesel engines can also utilize thermal barrier coatings; they have been used successfully on piston crowns and exhaust valves of shipboard engines to combat lower grade fuel combustion corrosion.

  20. Thermophysical properties of selected powders for thermal barrier coatings

    OpenAIRE

    M. Drajewicz; M. Góral; M. Pytel; J. Sieniawski

    2012-01-01

    Purpose: Plasma-sprayed thermal barrier coatings often have the problems of spallation and cracking in service owing to their poor bond strength and high residual stresses. Functionally graded thermal barrier coatings with a gradual compositional variation from heat resistant ceramics to fracture-resistant metals are proposed to mitigate these problems.Design/methodology/approach: The results of measurements of thermal diffusivity by using one of the most modern experimental sets LFA 427 (Las...

  1. Multilayer Microlaminated Ceramic Thermal Barrier Coating

    National Research Council Canada - National Science Library

    Yu, Charles

    1997-01-01

    .... Both thermal and mechanical characteristics of the coatings can be potentially optimized, and the coating will be more tolerant towards strain damage, have better thermal insulation and provide...

  2. The Westinghouse Small Modular Reactor Design

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez Garcia, F. J.; Memmott, M. J.

    2012-07-01

    Westinghouse has developed a small modular reactor (SMR) which incorporates an integral pressurized water reactor (PWR) design. The Westinghouse SMR design also utilizes many of the key features and innovative concepts from the AP1000 plant, including passive safety systems.

  3. Are thermal barriers "higher" in deep sea turtle nests?

    OpenAIRE

    Santidri?n Tomillo, Pilar; Fonseca, Luis; Paladino, Frank V.; Spotila, James R.; Oro, Daniel

    2017-01-01

    Thermal tolerances are affected by the range of temperatures that species encounter in their habitat. Daniel Janzen hypothesized in his "Why mountain passes are higher in the tropics" that temperature gradients were effective barriers to animal movements where climatic uniformity was high. Sea turtles bury their eggs providing some thermal stability that varies with depth. We assessed the relationship between thermal uniformity and thermal tolerance in nests of three species of sea turtles. W...

  4. Westinghouse Small Modular Reactor nuclear steam supply system design

    Energy Technology Data Exchange (ETDEWEB)

    Memmott, M. J.; Harkness, A. W.; Van Wyk, J. [Westinghouse Electric Company LLC, 600 Cranberry Woods Drive, Cranberry Twp. PA 16066 (United States)

    2012-07-01

    The Westinghouse Small Modular Reactor (SMR) is an 800 MWt (>225 MWe) integral pressurized water reactor (iPWR), in which all of the components typically associated with the nuclear steam supply system (NSSS) of a nuclear power plant are incorporated within a single reactor pressure vessel. This paper is the first in a series of four papers which describe the design and functionality of the Westinghouse SMR. Also described in this series are the key drivers influencing the design of the Westinghouse SMR and the unique passive safety features of the Westinghouse SMR. Several critical motivators contributed to the development and integration of the Westinghouse SMR design. These design driving motivators dictated the final configuration of the Westinghouse SMR to varying degrees, depending on the specific features under consideration. These design drivers include safety, economics, AP1000{sup R} reactor expertise and experience, research and development requirements, functionality of systems and components, size of the systems and vessels, simplicity of design, and licensing requirements. The Westinghouse SMR NSSS consists of an integral reactor vessel within a compact containment vessel. The core is located in the bottom of the reactor vessel and is composed of 89 modified Westinghouse 17x17 Robust Fuel Assemblies (RFA). These modified fuel assemblies have an active core length of only 2.4 m (8 ft) long, and the entirety of the core is encompassed by a radial reflector. The Westinghouse SMR core operates on a 24 month fuel cycle. The reactor vessel is approximately 24.4 m (80 ft) long and 3.7 m (12 ft) in diameter in order to facilitate standard rail shipping to the site. The reactor vessel houses hot and cold leg channels to facilitate coolant flow, control rod drive mechanisms (CRDM), instrumentation and cabling, an intermediate flange to separate flow and instrumentation and facilitate simpler refueling, a pressurizer, a straight tube, recirculating steam

  5. Simulation of thermo-Elastics Properties of Thermal Barrier Coatings ...

    African Journals Online (AJOL)

    Thermal barrier coatings are used to protect different parts in compressors and turbines from heat. They are generally composed of two layers, one metallic layer providing resistance to heat corrosion and oxidation, and one thermally insulating ceramic layer. Two different techniques are industrially used. Plasma spray ...

  6. An Overview of Westinghouse Realistic Large Break LOCA Evaluation Model

    Directory of Open Access Journals (Sweden)

    Cesare Frepoli

    2008-01-01

    Full Text Available Since the 1988 amendment of the 10 CFR 50.46 rule in 1988, Westinghouse has been developing and applying realistic or best-estimate methods to perform LOCA safety analyses. A realistic analysis requires the execution of various realistic LOCA transient simulations where the effect of both model and input uncertainties are ranged and propagated throughout the transients. The outcome is typically a range of results with associated probabilities. The thermal/hydraulic code is the engine of the methodology but a procedure is developed to assess the code and determine its biases and uncertainties. In addition, inputs to the simulation are also affected by uncertainty and these uncertainties are incorporated into the process. Several approaches have been proposed and applied in the industry in the framework of best-estimate methods. Most of the implementations, including Westinghouse, follow the Code Scaling, Applicability and Uncertainty (CSAU methodology. Westinghouse methodology is based on the use of the WCOBRA/TRAC thermal-hydraulic code. The paper starts with an overview of the regulations and its interpretation in the context of realistic analysis. The CSAU roadmap is reviewed in the context of its implementation in the Westinghouse evaluation model. An overview of the code (WCOBRA/TRAC and methodology is provided. Finally, the recent evolution to nonparametric statistics in the current edition of the W methodology is discussed. Sample results of a typical large break LOCA analysis for a PWR are provided.

  7. Are thermal barriers "higher" in deep sea turtle nests?

    Science.gov (United States)

    Santidrián Tomillo, Pilar; Fonseca, Luis; Paladino, Frank V; Spotila, James R; Oro, Daniel

    2017-01-01

    Thermal tolerances are affected by the range of temperatures that species encounter in their habitat. Daniel Janzen hypothesized in his "Why mountain passes are higher in the tropics" that temperature gradients were effective barriers to animal movements where climatic uniformity was high. Sea turtles bury their eggs providing some thermal stability that varies with depth. We assessed the relationship between thermal uniformity and thermal tolerance in nests of three species of sea turtles. We considered that barriers were "high" when small thermal changes had comparatively large effects and "low" when the effects were small. Mean temperature was lower and fluctuated less in species that dig deeper nests. Thermal barriers were comparatively "higher" in leatherback turtle (Dermochelys coriacea) nests, which were the deepest, as embryo mortality increased at lower "high" temperatures than in olive ridley (Lepidochelys olivacea) and green turtle (Chelonia mydas) nests. Sea turtles have temperature-dependent sex determination (TSD) and embryo mortality increased as temperature approached the upper end of the transitional range of temperatures (TRT) that produces both sexes (temperature producing 100% female offspring) in leatherback and olive ridley turtles. As thermal barriers are "higher" in some species than in others, the effects of climate warming on embryo mortality is likely to vary among sea turtles. Population resilience to climate warming may also depend on the balance between temperatures that produce female offspring and those that reduce embryo survival.

  8. Are thermal barriers "higher" in deep sea turtle nests?

    Directory of Open Access Journals (Sweden)

    Pilar Santidrián Tomillo

    Full Text Available Thermal tolerances are affected by the range of temperatures that species encounter in their habitat. Daniel Janzen hypothesized in his "Why mountain passes are higher in the tropics" that temperature gradients were effective barriers to animal movements where climatic uniformity was high. Sea turtles bury their eggs providing some thermal stability that varies with depth. We assessed the relationship between thermal uniformity and thermal tolerance in nests of three species of sea turtles. We considered that barriers were "high" when small thermal changes had comparatively large effects and "low" when the effects were small. Mean temperature was lower and fluctuated less in species that dig deeper nests. Thermal barriers were comparatively "higher" in leatherback turtle (Dermochelys coriacea nests, which were the deepest, as embryo mortality increased at lower "high" temperatures than in olive ridley (Lepidochelys olivacea and green turtle (Chelonia mydas nests. Sea turtles have temperature-dependent sex determination (TSD and embryo mortality increased as temperature approached the upper end of the transitional range of temperatures (TRT that produces both sexes (temperature producing 100% female offspring in leatherback and olive ridley turtles. As thermal barriers are "higher" in some species than in others, the effects of climate warming on embryo mortality is likely to vary among sea turtles. Population resilience to climate warming may also depend on the balance between temperatures that produce female offspring and those that reduce embryo survival.

  9. Thermal model of attic systems with radiant barriers

    Energy Technology Data Exchange (ETDEWEB)

    Wilkes, K.E.

    1991-07-01

    This report summarizes the first phase of a project to model the thermal performance of radiant barriers. The objective of this phase of the project was to develop a refined model for the thermal performance of residential house attics, with and without radiant barriers, and to verify the model by comparing its predictions against selected existing experimental thermal performance data. Models for the thermal performance of attics with and without radiant barriers have been developed and implemented on an IBM PC/AT computer. The validity of the models has been tested by comparing their predictions with ceiling heat fluxes measured in a number of laboratory and field experiments on attics with and without radiant barriers. Cumulative heat flows predicted by the models were usually within about 5 to 10 percent of measured values. In future phases of the project, the models for attic/radiant barrier performance will be coupled with a whole-house model and further comparisons with experimental data will be made. Following this, the models will be utilized to provide an initial assessment of the energy savings potential of radiant barriers in various configurations and under various climatic conditions. 38 refs., 14 figs., 22 tabs.

  10. Advanced Thermal Barrier and Environmental Barrier Coating Development at NASA GRC

    Science.gov (United States)

    Zhu, Dongming; Robinson, Craig

    2017-01-01

    This presentation summarizes NASA's advanced thermal barrier and environmental barrier coating systems, and the coating performance improvements that has recently been achieved and documented in laboratory simulated rig test conditions. One of the emphases has been placed on the toughness and impact resistance enhancements of the low conductivity, defect cluster thermal barrier coating systems. The advances in the next generation environmental barrier coatings for SiCSiC ceramic matrix composites have also been highlighted, particularly in the design of a new series of oxide-silicate composition systems to be integrated with next generation SiC-SiC turbine engine components for 2700F coating applications. Major technical barriers in developing the thermal and environmental barrier coating systems are also described. The performance and model validations in the rig simulated turbine combustion, heat flux, steam and calcium-magnesium-aluminosilicate (CMAS) environments have helped the current progress in improved temperature capability, environmental stability, and long-term fatigue-environment system durability of the advanced thermal and environmental barrier coating systems.

  11. Development of Thermal Barriers for Solid Rocket Motor Nozzle Joints

    Science.gov (United States)

    Steinetz, Bruce M.; Dunlap, Patrick H., Jr.

    1999-01-01

    The Space Shuttle solid rocket motor case assembly joints are sealed using conventional 0-ring seals. The 5500+F combustion gases are kept a safe distance away from the seals by thick layers of insulation. Special joint-fill compounds are used to fill the joints in the insulation to prevent a direct flowpath to the seals. On a number of occasions. NASA has observed in several of the rocket nozzle assembly joints hot gas penetration through defects in the joint- fill compound. The current nozzle-to-case joint design incorporates primary, secondary and wiper (inner-most) 0-rings and polysulfide joint-fill compound. In the current design, 1 out of 7 motors experience hot gas to the wiper 0-ring. Though the condition does not threaten motor safety, evidence of hot gas to the wiper 0-ring results in extensive reviews before resuming flight. NASA and solid rocket motor manufacturer Thiokol are working to improve the nozzle-to-case joint design by implementing a more reliable J-leg design and a thermal barrier, This paper presents burn-resistance, temperature drop, flow and resiliency test results for several types of NASA braided carbon-fiber thermal barriers. Burn tests were performed to determine the time to burn through each of the thermal barriers when exposed to the flame of an oxy-acetylene torch (5500 F), representative of the 5500 F solid rocket motor combustion temperatures. Thermal barriers braided out of carbon fibers endured the flame for over 6 minutes, three times longer than solid rocket motor burn time. Tests were performed on two thermal barrier braid architectures, denoted Carbon-3 and Carbon-6, to measure the temperature drop across and along the barrier in a compressed state when subjected to the flame of an oxyacetylene torch. Carbon-3 and Carbon-6 thermal barriers were excellent insulators causing temperature drops through their diameter of up to a 2800 and 2560 F. respectively. Gas temperature 1/4" downstream of the thermal barrier were within the

  12. Thermal barrier coating experience in the gas turbine engine

    Science.gov (United States)

    Bose, S.; Demasi-Marcin, J.

    1995-01-01

    Thermal Barrier Coatings (TBC), provide thermal insulation and oxidation resistance in an environment consisting of hot combustion gases. TBC's consist of a two layer system. The outer ceramic layer provides good thermal insulation due to the low thermal conductivity of the ceramic coatings used, while the inner metallic bond coat layer provides needed oxidation resistance to the underlying superalloy. Pratt & Whitney has over a decade of experience with several generations of TBC systems on turbine airfoils. This paper will focus on the latest TBC field experience along with a proposed durability model.

  13. Thermal-barrier coatings for utility gas turbines

    Science.gov (United States)

    Levine, S. R.; Miller, R. A.

    1982-01-01

    The potential of thermal barrier coatings for use in utility gas turbines was assessed. Pressurized passage and ambient pressure doped fuel burner rig tests revealed that thermal barrier coatings are not resistant to dirty combustion environments. However, present thermal barrier coatings, such as duplex partially stabilized zirconia and duplex Ca2SiO4 have ample resistance to the thermo-mechanical stress and temperature levels anticipated for heavy duty gas turbines firing clean fuel as revealed by clean fuel pressurized passage and ambient pressure burner rig tests. Thus, it is appropriate to evaluate such coatings on blades, vanes and combustors in the field. However, such field tests should be backed up with adequate effort in the areas of coating application technology and design analysis so that the field tests yield unequivocal results.

  14. Thermal Barrier Coatings for Advanced Gas Turbine and Diesel Engines

    Science.gov (United States)

    Zhu, Dongming; Miller, Robert A.

    1999-01-01

    Ceramic thermal barrier coatings (TBCS) have been developed for advanced gas turbine and diesel engine applications to improve engine reliability and fuel efficiency. However, durability issues of these thermal barrier coatings under high temperature cyclic conditions are still of major concern. The coating failure depends not only on the coating, but also on the ceramic sintering/creep and bond coat oxidation under the operating conditions. Novel test approaches have been established to obtain critical thermomechanical and thermophysical properties of the coating systems under near-realistic transient and steady state temperature and stress gradients encountered in advanced engine systems. This paper presents detailed experimental and modeling results describing processes occurring in the ZrO2-Y2O3 thermal barrier coating systems, thus providing a framework for developing strategies to manage ceramic coating architecture, microstructure and properties.

  15. Ceramic thermal barrier coatings for electric utility gas turbine engines

    Science.gov (United States)

    Miller, R. A.

    1986-01-01

    Research and development into thermal barrier coatings for electric utility gas turbine engines is reviewed critically. The type of coating systems developed for aircraft applications are found to be preferred for clear fuel electric utility applications. These coating systems consists of a layer of plasma sprayed zirconia-yttria ceramic over a layer of MCrAly bond coat. They are not recommended for use when molten salts are presented. Efforts to understand coating degradation in dirty environments and to develop corrosion resistant thermal barrier coatings are discussed.

  16. Ceramic thermal barrier coatings for commercial gas turbine engines

    Science.gov (United States)

    Meier, Susan Manning; Gupta, Dinesh K.; Sheffler, Keith D.

    1991-01-01

    The paper provides an overview of the short history, current status, and future prospects of ceramic thermal barrier coatings for gas turbine engines. Particular attention is given to plasma-sprayed and electron beam-physical vapor deposited yttria-stabilized (7 wt pct Y2O3) zirconia systems. Recent advances include improvements in the spallation life of thermal barrier coatings, improved bond coat composition and spraying techniques, and improved component design. The discussion also covers field experience, life prediction modeling, and future directions in ceramic coatings in relation to gas turbine engine design.

  17. Hypersonic propulsion - Breaking the thermal barrier

    Science.gov (United States)

    Weidner, J. P.

    1993-01-01

    The challenges of hypersonic propulsion impose unique features on the hypersonic vehicle - from large volume requirements to contain cryogenic fuel to airframe-integrated propulsion required to process sufficient quantities of air. Additional challenges exist in the design of the propulsion module that must be capable of efficiently processing air at very high enthalpies, adding and mixing fuel at supersonic speeds and expanding the exhaust products to generate thrust greater than drag. The paper explores the unique challenges of the integrated hypersonic propulsion system, addresses propulsion cycle selection to cope with the severe thermal environment and reviews the direction of propulsion research at hypervelocity speeds.

  18. INFLUENCE OF WORKPIECE SURFACE PREPARATION ON THERMAL BARRIER COATING DURABILITY

    Directory of Open Access Journals (Sweden)

    M. A. Petrova

    2014-01-01

    Full Text Available Article deals with the impact of workpiece surface quality on adhesive strength and durability of thermal barrier coating. The result revealed that the roughness of metal layer influences on the adhesion of ceramic coating and depends the thickness of ceramic crystals when using method of Electron beam deposition.

  19. Ceramic Thermal Barriers For Dirty-Fuel Turbines

    Science.gov (United States)

    Miller, Robert A.

    1988-01-01

    Report discusses performances of ceramic thermal-barrier coating materials for use in electric-utility gas-turbine engines. Variations of standard coating evaluated in search for coating resistant to dirty fuel. Variations included alterations of level of yttria, replacement of yttria by other stabilizers, controlling surface density (by plasma spray processing, infiltration, laser glazing, or sputtering), and interface treatments.

  20. Computational design and experimental validation of new thermal barrier systems

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Shengmin [Louisiana State Univ., Baton Rouge, LA (United States)

    2015-03-31

    The focus of this project is on the development of a reliable and efficient ab initio based computational high temperature material design method which can be used to assist the Thermal Barrier Coating (TBC) bond-coat and top-coat design. Experimental evaluations on the new TBCs are conducted to confirm the new TBCs’ properties. Southern University is the subcontractor on this project with a focus on the computational simulation method development. We have performed ab initio density functional theory (DFT) method and molecular dynamics simulation on screening the top coats and bond coats for gas turbine thermal barrier coating design and validation applications. For experimental validations, our focus is on the hot corrosion performance of different TBC systems. For example, for one of the top coatings studied, we examined the thermal stability of TaZr2.75O8 and confirmed it’s hot corrosion performance.

  1. Chemical Vapor Deposition of Turbine Thermal Barrier Coatings

    Science.gov (United States)

    Haven, Victor E.

    1999-01-01

    Ceramic thermal barrier coatings extend the operating temperature range of actively cooled gas turbine components, therefore increasing thermal efficiency. Performance and lifetime of existing ceram ic coatings are limited by spallation during heating and cooling cycles. Spallation of the ceramic is a function of its microstructure, which is determined by the deposition method. This research is investigating metalorganic chemical vapor deposition (MOCVD) of yttria stabilized zirconia to improve performance and reduce costs relative to electron beam physical vapor deposition. Coatings are deposited in an induction-heated, low-pressure reactor at 10 microns per hour. The coating's composition, structure, and response to the turbine environment will be characterized.

  2. Computational Design and Experimental Validation of New Thermal Barrier Systems

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Shengmin; Yang, Shizhong; Khosravi, Ebrahim

    2014-04-01

    This project (10/01/2010-9/30/2014), “Computational Design and Experimental Validation of New Thermal Barrier Systems”, originates from Louisiana State University (LSU) Mechanical Engineering Department and Southern University (SU) Department of Computer Science. This project will directly support the technical goals specified in DE-FOA-0000248, Topic Area 3: Turbine Materials, by addressing key technologies needed to enable the development of advanced turbines and turbine-based systems that will operate safely and efficiently using coal-derived synthesis gases. In this project, the focus is to develop and implement novel molecular dynamics method to improve the efficiency of simulation on novel TBC materials; perform high performance computing (HPC) on complex TBC structures to screen the most promising TBC compositions; perform material characterizations and oxidation/corrosion tests; and demonstrate our new thermal barrier coating (TBC) systems experimentally under integrated gasification combined cycle (IGCC) environments.

  3. Computational Design and Experimental Validation of New Thermal Barrier Systems

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Shengmin; Yang, Shizhong; Khosravi, Ebrahim

    2012-10-01

    This project (10/01/2010-9/30/2013), “Computational Design and Experimental Validation of New Thermal Barrier Systems”, originates from Louisiana State University (LSU) Mechanical Engineering Department and Southern University (SU) Department of Computer Science. This project will directly support the technical goals specified in DEFOA- 0000248, Topic Area 3: Turbine Materials, by addressing key technologies needed to enable the development of advanced turbines and turbine-based systems that will operate safely and efficiently using coal-derived synthesis gases. We will develop and implement novel molecular dynamics method to improve the efficiency of simulation on novel TBC materials; perform high performance computing (HPC) on complex TBC structures to screen the most promising TBC compositions; perform material characterizations and oxidation/corrosion tests; and demonstrate our new thermal barrier coating (TBC) systems experimentally under integrated gasification combined cycle (IGCC) environments. The durability of the coating will be examined using the proposed Durability Test Rig.

  4. Bond strength and stress measurements in thermal barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Gell, M.; Jordan, E. [Univ. of Connecticut, Storrs, CT (United States)

    1995-10-01

    Thermal barrier coatings have been used extensively in aircraft gas turbines for more than 15 years to insulate combustors and turbine vanes from the hot gas stream. Plasma sprayed thermal barrier coatings (TBCs) provide metal temperature reductions as much as 300{degrees}F, with improvements in durability of two times or more being achieved. The introduction of TBCs deposited by electron beam physical vapor deposition (EB-PVD) processes in the last five years has provided a major improvement in durability and also enabled TBCs to be applied to turbine blades for improved engine performance. To meet the aggressive Advanced Turbine Systems goals for efficiency, durability and the environment, it will be necessary to employ thermal barrier coatings on turbine airfoils and other hot section components. For The successful application of TBCs to ATS engines with 2600{degrees}F turbine inlet temperatures and required component lives 10 times greater than those for aircraft gas turbine engines, it is necessary to develop quantitative assessment techniques for TBC coating integrity with time and cycles in ATS engines. Thermal barrier coatings in production today consist of a metallic bond coat, such as an MCrAlY overlay coating or a platinum aluminide (Pt-Al) diffusion coating. During heat treatment, both these coatings form a thin, tightly adherent alumina (Al{sub 2}O{sub 3}) film. Failure of TBC coatings in engine service occurs by spallation of the ceramic coating at or near the bond coat to alumina or the alumina to zirconia bonds. Thus, it is the initial strength of these bonds and the stresses at the bond plane, and their changes with engine exposure, that determines coating durability. The purpose of this program is to provide, for the first time, a quantitative assessment of TBC bond strength and bond plane stresses as a function of engine time and cycles.

  5. Technical review of Westinghouse`s Advanced Turbine Systems Program

    Energy Technology Data Exchange (ETDEWEB)

    Diakunchak, I.S.; Bannister, R.L. [Westinghouse Electric Corp., Orlando, FL (United States)

    1995-10-01

    U.S. Department of Energy, Office of Fossil Energy Advanced Turbine Systems (ATS) Program is an ambitious program to develop the necessary technologies, which will result in a significant increase in natural gas-fired power generation plant efficiency, a decrease in cost of electricity and a decrease in harmful emissions. In Phase 1 of the ATS Program, preliminary investigations on different gas turbine cycles demonstrated that net plant efficiency greater than 60% could be achieved. The more promising cycles were evaluated in more detail in Phase 2 in order to select the one that would achieve all of the program goals. The closed-loop cooled combined cycle was selected because it offered the best solution with the least risk for exceeding the ATS Program goals of net plant efficiency, emissions, cost of electricity, reliability, availability, and maintainability (RAM), and commercialization in the year 2000. The Westinghouse ATS plant is based on an advanced gas turbine design combined with an advanced steam. turbine and a high efficiency generator. To enhance achievement of the challenging performance, emissions, and RAM goals, current technologies are being extended and new technologies developed. The attainment of ATS performance goal necessitates advancements in aerodynamics, sealing, cooling, coatings, and materials technologies. To reduce emissions to the required levels, demands a development effort in the following combustion technology areas: premixed ultra low NOx combustion, catalytic combustion, combustion instabilities, and optical diagnostics. To achieve the RAM targets, requires the utilization of proven design features, with quantified risk analysis, and advanced materials, coatings, and cooling technologies. Phase 2 research and development projects currently in progress, as well as those planned for Phase 3, will result in advances in gas turbine technology and greatly contribute to ATS Program success.

  6. Residual stress evolution regularity in thermal barrier coatings under thermal shock loading

    Directory of Open Access Journals (Sweden)

    Ximin Chen

    2014-01-01

    Full Text Available Residual stress evolution regularity in thermal barrier ceramic coatings (TBCs under different cycles of thermal shock loading of 1100°C was investigated by the microscopic digital image correlation (DIC and micro-Raman spectroscopy, respectively. The obtained results showed that, as the cycle number of the thermal shock loading increases, the evolution of the residual stress undergoes three distinct stages: a sharp increase, a gradual change, and a reduction. The extension stress near the TBC surface is fast transformed to compressive one through just one thermal cycle. After different thermal shock cycles with peak temperature of 1100°C, phase transformation in TBC does not happen, whereas the generation, development, evolution of the thermally grown oxide (TGO layer and micro-cracks are the main reasons causing the evolution regularity of the residual stress.

  7. THERMAL PROPERTIES OF TRANSPARENT BARRIER MODIFIED WITH ORGANIC PCMS

    Directory of Open Access Journals (Sweden)

    Michał MUSIAŁ

    2016-03-01

    Full Text Available Renewable energy sources are increasingly often applied in civil engineering as a mean to reduce buildings energy demand for heating. One of the ways to reduce HVAC energy demand is to limit heat transfer and excessive solar gain through building's glazed barriers. Preliminary results of the research conducted on organic PCM-modified transparent barrier are presented in this paper. Multiple publications concerning PCMs application in structural materials have recently appeared. Most of them are focused on modification of structure of non-transparent sections of buildings' envelope. Augmenting a glazed barrier with PCMs increases its heat capacity and thermal resistance. The most important feature of the assembly is the thermal buffer, a product of PCM's considerable value of specific latent heat. Research were conducted on a triple-pane transparent rectangular barrier, that constituted one of the faces of cubic chamber. Internal volume of the chamber was 1m3. The applied PCM was a mixture of saturated and non-saturated hydrocarbons. The described assembly was subjected to temperature and radiation that occur in Poland during winter. Glazing temperature, melted/total PCM ratio were measured, as well as energy demand for keeping internal temperature at constant level. Measurements were made in steady states, for various PCM layer thickness. The influence of the modification on energy demand was determined, along with the most effective and rational thickness of PCM layer to be applied. Conducted research enabled to develop a basis for further investigation of PCMs application in civil engineering.

  8. Thermal Conductivity in Suspension Sprayed Thermal Barrier Coatings: Modeling and Experiments

    Science.gov (United States)

    Ganvir, Ashish; Kumara, Chamara; Gupta, Mohit; Nylen, Per

    2017-01-01

    Axial suspension plasma spraying (ASPS) can generate microstructures with higher porosity and pores in the size range from submicron to nanometer. ASPS thermal barrier coatings (TBC) have already shown a great potential to produce low thermal conductivity coatings for gas turbine applications. It is important to understand the fundamental relationships between microstructural defects in ASPS coatings such as crystallite boundaries, porosity etc. and thermal conductivity. Object-oriented finite element (OOF) analysis has been shown as an effective tool for evaluating thermal conductivity of conventional TBCs as this method is capable of incorporating the inherent microstructure in the model. The objective of this work was to analyze the thermal conductivity of ASPS TBCs using experimental techniques and also to evaluate a procedure where OOF can be used to predict and analyze the thermal conductivity for these coatings. Verification of the model was done by comparing modeling results with the experimental thermal conductivity. The results showed that the varied scaled porosity has a significant influence on the thermal conductivity. Smaller crystallites and higher overall porosity content resulted in lower thermal conductivity. It was shown that OOF could be a powerful tool to predict and rank thermal conductivity of ASPS TBCs.

  9. Perspective on thermal barrier coatings for industrial gas turbine applications

    Science.gov (United States)

    Mutasim, Zaher; Brentnall, William

    1995-01-01

    Thermal barrier coatings (TBC's) have been used in high thrust aircraft engines for many years, and have proved to be very effective in providing thermal protection and increasing engine efficiencies. TBC life requirements for aircraft engines are typically less than those required for industrial gas turbines. This paper describes current and future applications of TBC's in industrial gas turbine engines. Early testing and applications of TBC's is reviewed. Areas of concern from the engine designer's and materials engineer's perspective are identified and evaluated. This paper focuses on the key factors that are expected to influence utilization of TBC's in advanced industrial gas turbine engines. It is anticipated that reliable, durable and highly effective coating systems will be produced that will ultimately improve engine efficiency and performance.

  10. The Lattice and Thermal Radiation Conductivity of Thermal Barrier Coatings: Models and Experiments

    Science.gov (United States)

    Zhu, Dongming; Spuckler, Charles M.

    2010-01-01

    The lattice and radiation conductivity of ZrO2-Y2O3 thermal barrier coatings was evaluated using a laser heat flux approach. A diffusion model has been established to correlate the coating apparent thermal conductivity to the lattice and radiation conductivity. The radiation conductivity component can be expressed as a function of temperature, coating material scattering, and absorption properties. High temperature scattering and absorption of the coating systems can be also derived based on the testing results using the modeling approach. A comparison has been made for the gray and nongray coating models in the plasma-sprayed thermal barrier coatings. The model prediction is found to have a good agreement with experimental observations.

  11. Coherent gradient sensing method for measuring thermal stress field of thermal barrier coating structures

    Directory of Open Access Journals (Sweden)

    Kang Ma

    2017-01-01

    Full Text Available Coherent gradient sensing (CGS method can be used to measure the slope of a reflective surface, and has the merits of full-field, non-contact, and real-time measurement. In this study, the thermal stress field of thermal barrier coating (TBC structures is measured by CGS method. Two kinds of powders were sprayed onto Ni-based alloy using a plasma spraying method to obtain two groups of film–substrate specimens. The specimens were then heated with an oxy-acetylene flame. The resulting thermal mismatch between the film and substrate led to out-of-plane deformation of the specimen. The deformation was measured by the reflective CGS method and the thermal stress field of the structure was obtained through calibration with the help of finite element analysis. Both the experiment and numerical results showed that the thermal stress field of TBC structures can be successfully measured by CGS method.

  12. Indentation methods for adhesion measurement in thermal barrier coating systems

    Science.gov (United States)

    Ma, Qin

    This thesis investigates the fundamentals of indentation-induced delamination of electron beam physical vapor deposition thermal barrier coatings (EB-PVD TBCs). Thermal barrier coatings are thin ceramic coatings used to insulate gas turbine components. In the as-processed state, TBCs are well-bonded to the metallic substrate they are deposited upon. However, as these coatings are exposed to high temperatures during turbine operation, they lose their adhesion. The goal of this thesis is to determine how to use indentation testing techniques, coupled with fracture mechanics principles, to track this loss of adhesion and to identify mechanisms causing it. This thesis addresses four primary topics. First, a detailed fracture mechanics analysis of indentation-induced delamination is made, including the quantification of energy release rates, interfacial toughnesses and mode mix. The second topic addressed is application of the indentation test to track toughness losses in TBC systems subjected to a variety of thermal exposures. Three subtopics are included: (1) mechanism-based tests for the isothermal dry air exposures; (2) mechanism-based tests for exposures with water vapor and (3) mechanism-based tests for cyclic thermal exposures. In the first subtopic, TGO thickening and TBC sintering are modeled. Various mechanisms that lead to toughness degradation are discussed and analyzed quantitatively. An Arrhenius analysis has been performed to understand accelerated testing methods. The second subtopic presents the results of toughness degradation and the evolution of microstructures due to isothermal exposure with water vapor. The third subtopic investigates the toughness degradation for cyclic thermal exposures in dry air. Piezospectroscopy method has been applied to track the evolution of residual stresses in the TGO layer with thermal cycles. Quantitative analysis has been provided to give insights into the effects of oxide damage during thermal cycling. The final two

  13. Performance Evaluation and Modeling of Erosion Resistant Turbine Engine Thermal Barrier Coatings

    Science.gov (United States)

    Miller, Robert A.; Zhu, Dongming; Kuczmarski, Maria

    2008-01-01

    The erosion resistant turbine thermal barrier coating system is critical to the rotorcraft engine performance and durability. The objective of this work was to determine erosion resistance of advanced thermal barrier coating systems under simulated engine erosion and thermal gradient environments, thus validating a new thermal barrier coating turbine blade technology for future rotorcraft applications. A high velocity burner rig based erosion test approach was established and a new series of rare earth oxide- and TiO2/Ta2O5- alloyed, ZrO2-based low conductivity thermal barrier coatings were designed and processed. The low conductivity thermal barrier coating systems demonstrated significant improvements in the erosion resistance. A comprehensive model based on accumulated strain damage low cycle fatigue is formulated for blade erosion life prediction. The work is currently aiming at the simulated engine erosion testing of advanced thermal barrier coated turbine blades to establish and validate the coating life prediction models.

  14. Engineered Barrier Systems Thermal-Hydraulic-Chemical Column Test Report

    Energy Technology Data Exchange (ETDEWEB)

    W.E. Lowry

    2001-12-13

    The Engineered Barrier System (EBS) Thermal-Hydraulic-Chemical (THC) Column Tests provide data needed for model validation. The EBS Degradation, Flow, and Transport Process Modeling Report (PMR) will be based on supporting models for in-drift THC coupled processes, and the in-drift physical and chemical environment. These models describe the complex chemical interaction of EBS materials, including granular materials, with the thermal and hydrologic conditions that will be present in the repository emplacement drifts. Of particular interest are the coupled processes that result in mineral and salt dissolution/precipitation in the EBS environment. Test data are needed for thermal, hydrologic, and geochemical model validation and to support selection of introduced materials (CRWMS M&O 1999c). These column tests evaluated granular crushed tuff as potential invert ballast or backfill material, under accelerated thermal and hydrologic environments. The objectives of the THC column testing are to: (1) Characterize THC coupled processes that could affect performance of EBS components, particularly the magnitude of permeability reduction (increases or decreases), the nature of minerals produced, and chemical fractionation (i.e., concentrative separation of salts and minerals due to boiling-point elevation). (2) Generate data for validating THC predictive models that will support the EBS Degradation, Flow, and Transport PMR, Rev. 01.

  15. Optical Diagnostics for High-Temperature Thermal Barrier Coatings

    Science.gov (United States)

    Eldridge, Jeffrey I.

    2009-01-01

    Thermal barrier coatings (TBCs) are typically composed of translucent ceramic oxides that provide thermal protection for metallic components exposed to high-temperature environments, such as in jet turbine engines. Taking advantage of the translucent nature of TBCs, optical diagnostics have been developed that can provide an informed assessment of TBC health that will allow mitigating action to be taken before TBC degradation threatens performance or safety. In particular, rare-earth-doped luminescent sublayers have been integrated into the TBC structure to produce luminescence that monitors TBC erosion, delamination, and temperature gradients. Erosion monitoring of TBC-coated specimens is demonstrated by utilizing visible luminescence that is excited from a sublayer that is exposed by erosion. TBC delamination monitoring is achieved in TBCs with a base rare-earth-doped luminescent sublayer by the reflectance-enhanced increase in luminescence produced in regions containing buried delamination cracks. TBC temperature monitoring is demonstrated using the temperature-dependent decay time for luminescence originating from the specific coating depth associated with a rare-earth-doped luminescent sublayer. The design and implementation of these TBCs with integrated luminescent sublayers is discussed, including co-doping strategies to produce more penetrating near-infrared luminescence. It is demonstrated that integration of the rare-earth-doped sublayers is achieved with no reduction in TBC life. In addition, results for multilayer TBCs designed to also perform as radiation barriers are also presented.

  16. Computational Design and Experimental Validation of New Thermal Barrier Systems

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Shengmin; Yang, Shizhong; Khosravi, Ebrahim

    2011-12-31

    This project (10/01/2010-9/30/2013), “Computational Design and Experimental Validation of New Thermal Barrier Systems”, originates from Louisiana State University (LSU) Mechanical Engineering Department and Southern University (SU) Department of Computer Science. This proposal will directly support the technical goals specified in DE-FOA-0000248, Topic Area 3: Turbine Materials, by addressing key technologies needed to enable the development of advanced turbines and turbine-based systems that will operate safely and efficiently using coal-derived synthesis gases. We will develop novel molecular dynamics method to improve the efficiency of simulation on novel TBC materials; we will perform high performance computing (HPC) on complex TBC structures to screen the most promising TBC compositions; we will perform material characterizations and oxidation/corrosion tests; and we will demonstrate our new Thermal barrier coating (TBC) systems experimentally under Integrated gasification combined cycle (IGCC) environments. The durability of the coating will be examined using the proposed High Temperature/High Pressure Durability Test Rig under real syngas product compositions.

  17. Thermal and Environmental Barrier Coatings for Advanced Turbine Engine Applications

    Science.gov (United States)

    Zhu, Dong-Ming; Miller, Robert A.

    2005-01-01

    Ceramic thermal and environmental barrier coatings (T/EBCs) will play a crucial role in advanced gas turbine engine systems because of their ability to significantly increase engine operating temperatures and reduce cooling requirements, thus help achieve engine low emission and high efficiency goals. Advanced T/EBCs are being developed for the low emission SiC/SiC ceramic matrix composite (CMC) combustor applications by extending the CMC liner and vane temperature capability to 1650 C (3000 F) in oxidizing and water vapor containing combustion environments. Low conductivity thermal barrier coatings (TBCs) are also being developed for metallic turbine airfoil and combustor applications, providing the component temperature capability up to 1650 C (3000 F). In this paper, ceramic coating development considerations and requirements for both the ceramic and metallic components will be described for engine high temperature and high-heat-flux applications. The underlying coating failure mechanisms and life prediction approaches will be discussed based on the simulated engine tests and fracture mechanics modeling results.

  18. Study on Preparation Technologies of Thermal Barrier Coatings

    Science.gov (United States)

    Wang, Tao; Wang, Ning; Li, Yang; Wang, Hao; Tang, Jie; Wang, Yunshan

    Thermal barrier coatings (TBCs) is one of the main key technology for the high-pressure turbine blades which are the main components of the high-performance aerospace engines. It offers protection for underline metallic components from corrosion, oxidation and localized melting by insulating the metal from hot gases in the engine core. The properties and lifetime of TBCs are greatly influenced by the preparation technology, which includes plasma spraying (PS), physical vapor deposition (PVD) and laser re-melting (LM). In this paper, three technologies used to prepare the TBCs are reviewed. Resulting features of coating fabricated by each technology are also discussed such as: the porosity, the thermally grown oxide (TGO), the erosion resistance, the thermal shock and so on. Especially, it is pointed out that the performances of gradient coating and nano-coating are better than the traditional coatings. In addition, it is widely accepted that laser can be applied to re-melt the PS coating and even directly clad the gradient coating. In the future, the traditional preparation technology should be improved continually in order to enhance the coating lifetime, enhance the properties of coating and lower the cost of process. Moreover, the researches on gradient-nano-structured coatings preparation are absent and should be done with emphasis since the nano-structure and gradient structure can both benefit the lifetime and properties of coatings.

  19. Thermal Conductivity and Elastic Modulus Evolution of Thermal Barrier Coatings under High Heat Flux Conditions

    Science.gov (United States)

    Zhu, Dongming; Miller, Robert A.

    1999-01-01

    Laser high heat flux test approaches have been established to obtain critical properties of ceramic thermal barrier coatings (TBCs) under near-realistic temperature and thermal gradients that may he encountered in advanced engine systems. Thermal conductivity change kinetics of a thin ceramic coating were continuously monitored in real time at various test temperatures. A significant thermal conductivity increase was observed during the laser simulated engine heat flux tests. For a 0.25 mm thick ZrO2-8%Y2O3 coating system, the overall thermal conductivity increased from the initial value of 1.0 W/m-K to 1. 15 W/m-K, 1. 19 W/m-K and 1.5 W/m-K after 30 hour testing at surface temperatures of 990C, 1100C, and 1320C. respectively. Hardness and modulus gradients across a 1.5 mm thick TBC system were also determined as a function of laser testing time using the laser sintering/creep and micro-indentation techniques. The coating Knoop hardness values increased from the initial hardness value of 4 GPa to 5 GPa near the ceramic/bond coat interface, and to 7.5 GPa at the ceramic coating surface after 120 hour testing. The ceramic surface modulus increased from an initial value of about 70 GPa to a final value of 125 GPa. The increase in thermal conductivity and the evolution of significant hardness and modulus gradients in the TBC systems are attributed to sintering-induced micro-porosity gradients under the laser-imposed high thermal gradient conditions. The test techniques provide a viable means for obtaining coating data for use in design, development, stress modeling, and life prediction for various thermal barrier coating applications.

  20. Thermal barrier coatings (TBC's) for high heat flux thrust chambers

    Science.gov (United States)

    Bradley, Christopher M.

    The last 30 years materials engineers have been under continual pressure to develop materials with a greater temperature potential or to produce configurations that can be effectively cooled or otherwise protected at elevated temperature conditions. Turbines and thrust chambers produce some of the harshest service conditions for materials which lead to the challenges engineers face in order to increase the efficiencies of current technologies due to the energy crisis that the world is facing. The key tasks for the future of gas turbines are to increase overall efficiencies to meet energy demands of a growing world population and reduce the harmful emissions to protect the environment. Airfoils or blades tend to be the limiting factor when it comes to the performance of the turbine because of their complex design making them difficult to cool as well as limitations of their thermal properties. Key tasks for space transportation it to lower costs while increasing operational efficiency and reliability of our space launchers. The important factor to take into consideration is the rocket nozzle design. The design of the rocket nozzle or thrust chamber has to take into account many constraints including external loads, heat transfer, transients, and the fluid dynamics of expanded hot gases. Turbine engines can have increased efficiencies if the inlet temperature for combustion is higher, increased compressor capacity and lighter weight materials. In order to push for higher temperatures, engineers need to come up with a way to compensate for increased temperatures because material systems that are being used are either at or near their useful properties limit. Before thermal barrier coatings were applied to hot-section components, material alloy systems were able to withstand the service conditions necessary. But, with the increased demand for performance, higher temperatures and pressures have become too much for those alloy systems. Controlled chemistry of hot

  1. The Development of Erosion and Impact Resistant Turbine Airfoil Thermal Barrier Coatings

    Science.gov (United States)

    Zhu, Dongming; Miller, Robert A.

    2007-01-01

    Thermal barrier coatings are used in gas turbine engines to protect engine hot-section components in the harsh combustion environments and extend component lifetimes. For thermal barrier coatings designed for turbine airfoil applications, further improved erosion and impact resistance are crucial for engine performance and durability. Advanced erosion resistant thermal barrier coatings are being developed, with a current emphasis on the toughness improvements using a combined rare earth- and transition metal-oxide doping approach. The performance of the doped thermal barrier coatings has been evaluated in burner rig and laser heat-flux rig simulated engine erosion and thermal gradient environments. The results have shown that the coating composition optimizations can effectively improve the erosion and impact resistance of the coating systems, while maintaining low thermal conductivity and cyclic durability. The erosion and impact damage mechanisms of the thermal barrier coatings will also be discussed.

  2. Deposition stress effects on thermal barrier coating burner rig life

    Science.gov (United States)

    Watson, J. W.; Levine, S. R.

    1984-01-01

    A study of the effect of plasma spray processing parameters on the life of a two layer thermal barrier coating was conducted. The ceramic layer was plasma sprayed at plasma arc currents of 900 and 600 amps onto uncooled tubes, cooled tubes, and solid bars of Waspalloy in a lathe with 1 or 8 passes of the plasma gun. These processing changes affected the residual stress state of the coating. When the specimens were tested in a Mach 0.3 cyclic burner rig at 1130 deg C, a wide range of coating lives resulted. Processing factors which reduced the residual stress state in the coating, such as reduced plasma temperature and increased heat dissipation, significantly increased coating life.

  3. Thermal barrier and support for nuclear reactor fuel core

    Science.gov (United States)

    Betts, Jr., William S.; Pickering, J. Larry; Black, William E.

    1987-01-01

    A thermal barrier/core support for the fuel core of a nuclear reactor having a metallic cylinder secured to the reactor vessel liner and surrounded by fibrous insulation material. A top cap is secured to the upper end of the metallic cylinder that locates and orients a cover block and post seat. Under normal operating conditions, the metallic cylinder supports the entire load exerted by its associated fuel core post. Disposed within the metallic cylinder is a column of ceramic material, the height of which is less than that of the metallic cylinder, and thus is not normally load bearing. In the event of a temperature excursion beyond the design limits of the metallic cylinder and resulting in deformation of the cylinder, the ceramic column will abut the top cap to support the fuel core post.

  4. Thermal barrier coating life modeling in aircraft gas turbine engines

    Science.gov (United States)

    Nissley, David M.

    1995-01-01

    Analytical models for predicting ceramic thermal barrier coating (TBC) spalling life in aircraft gas turbine engines are presented. Electron beam-physical vapor deposited (EB-PVD) and plasma sprayed TBC systems are discussed. An overview of the following TBC spalling mechanisms is presented: metal oxidation at the ceramic-metal interface, ceramic-metal interface stress singularities at edges and corners, ceramic-metal interface stresses caused by radius of curvature and interface roughness, material properties and mechanical behavior, temperature gradients, component design features and object impact damage. TBC spalling life analytical models are proposed based on observations of TBC spalling and plausible failure theories. TBC spalling was assumed to occur when the imposed stresses exceed the material strength (at or near the ceramic-metal interface). TBC failure knowledge gaps caused by lack of experimental evidence and analytical understanding are noted. The analytical models are considered initial engineering approaches that capture observed TBC failure trends.

  5. Thermal Barrier/Seal for Extreme Temperature Applications

    Science.gov (United States)

    Steinetz, Bruce M.; Dunlap, Patrick H., Jr.; Phelps, Jack; Bauer, Paul; Bond, Bruce; McCool, Alex (Technical Monitor)

    2002-01-01

    Large solid rocket motors, as found on the Space Shuttle, are fabricated in segments for manufacturing considerations, bolted together, and sealed using conventional Viton O-ring seals. Similarly the nine large solid rocket motor nozzles are assembled from several different segments, bolted together, and sealed at six joint locations using conventional O-ring seals. The 5500 F combustion gases are generally kept a safe distance away from the seals by thick layers of phenolic or rubber insulation. Joint-fill compounds, including RTV (room temperature vulcanized compound) and polysulfide filler, are used to fill the joints in the insulation to prevent a direct flow-path to the O-rings. Normally these two stages of protection are enough to prevent a direct flow-path of the 900-psi hot gases from reaching the temperature-sensitive O-ring seals. However, in the current design 1 out of 15 Space Shuttle solid rocket motors experience hot gas effects on the Joint 6 wiper (sacrificial) O-rings. Also worrisome is the fact that joints have experienced heat effects on materials between the RTV and the O-rings, and in two cases O-rings have experienced heat effects. These conditions lead to extensive reviews of the post-flight conditions as part of the effort to monitor flight safety. We have developed a braided carbon fiber thermal barrier to replace the joint fill compounds in the Space Shuttle solid rocket motor nozzles to reduce the incoming 5500 F combustion gas temperature and permit only cool (approximately 100 F) gas to reach the temperature-sensitive O-ring seals. Implementation of this thermal barrier provides more robust, consistent operation with shorter turn around times between Shuttle launches.

  6. Waste Package Outer Barrier Stress Due to Thermal Expansion with Various Barrier Gap Sizes

    Energy Technology Data Exchange (ETDEWEB)

    M. M. Lewis

    2001-11-27

    The objective of this activity is to determine the tangential stresses of the outer shell, due to uneven thermal expansion of the inner and outer shells of the current waste package (WP) designs. Based on the results of the calculation ''Waste Package Barrier Stresses Due to Thermal Expansion'', CAL-EBS-ME-000008 (ref. 10), only tangential stresses are considered for this calculation. The tangential stresses are significantly larger than the radial stresses associated with thermal expansion, and at the WP outer surface the radial stresses are equal to zero. The scope of this activity is limited to determining the tangential stresses the waste package outer shell is subject to due to the interference fit, produced by having two different shell coefficients of thermal expansions. The inner shell has a greater coefficient of thermal expansion than the outer shell, producing a pressure between the two shells. This calculation is associated with Waste Package Project. The calculations are performed for the 21-PWR (pressurized water reactor), 44-BWR (boiling water reactor), 24-BWR, 12-PWR Long, 5 DHLW/DOE SNF - Short (defense high-level waste/Department of Energy spent nuclear fuel), 2-MCO/2-DHLW (multi-canister overpack), and Naval SNF Long WP designs. The information provided by the sketches attached to this calculation is that of the potential design for the types of WPs considered in this calculation. This calculation is performed in accordance with the ''Technical Work Plan for: Waste Package Design Description for SR (Ref.7). The calculation is documented, reviewed, and approved in accordance with AP-3.12Q, Calculations (Ref.1).

  7. The Numerical Modeling of Thermal Stress Distribution in Thermal Barrier Coatings

    Directory of Open Access Journals (Sweden)

    Jasik A.

    2017-09-01

    Full Text Available The paper presents the results of numerical calculations of temperature and thermal stress distribution in thermal barrier coatings deposited by thermal spraying process on the nickel based superalloy. An assumption was made to apply conventional zirconium oxide modified with yttrium oxide (8YSZ and apply pyrochlore type material with formula La2Zr2O7. The bond coat was made of NiCoCrAlY. Analysis of the distribution of temperature and stresses in ceramic coatings of different thicknesses was performed in the function of bond-coat thickness and the type of ceramic insulation layer. It was revealed that the thickness of NiCrAlY bond-coat has not significant influence on the stress distribution, but there is relatively strong effect on temperature level. The most important factor influenced on stress distribution in TBC system is related with type and properties of ceramic insulation layer.

  8. Analysis of Thermal Radiation Effects on Temperatures in Turbine Engine Thermal Barrier Coatings

    Science.gov (United States)

    Siegel, Robert; Spuckler, Charles M.

    1998-01-01

    Thermal barrier coatings are important, and in some instances a necessity, for high temperature applications such as combustor liners, and turbine vanes and rotating blades for current and advanced turbine engines. Some of the insulating materials used for coatings, such as zirconia that currently has widespread use, are partially transparent to thermal radiation. A translucent coating permits energy to be transported internally by radiation, thereby increasing the total energy transfer and acting like an increase in thermal conductivity. This degrades the insulating ability of the coating. Because of the strong dependence of radiant emission on temperature, internal radiative transfer effects are increased as temperatures are raised. Hence evaluating the significance of internal radiation is of importance as temperatures are increased to obtain higher efficiencies in advanced engines.

  9. Bilayer Suspension Plasma-Sprayed Thermal Barrier Coatings with Enhanced Thermal Cyclic Lifetime: Experiments and Modeling

    Science.gov (United States)

    Gupta, Mohit; Kumara, Chamara; Nylén, Per

    2017-08-01

    Suspension plasma spraying (SPS) has been shown as a promising process to produce porous columnar strain tolerant coatings for thermal barrier coatings (TBCs) in gas turbine engines. However, the highly porous structure is vulnerable to crack propagation, especially near the topcoat-bondcoat interface where high stresses are generated due to thermal cycling. A topcoat layer with high toughness near the topcoat-bondcoat interface could be beneficial to enhance thermal cyclic lifetime of SPS TBCs. In this work, a bilayer coating system consisting of first a dense layer near the topcoat-bondcoat interface followed by a porous columnar layer was fabricated by SPS using Yttria-stabilised zirconia suspension. The objective of this work was to investigate if the bilayer topcoat architecture could enhance the thermal cyclic lifetime of SPS TBCs through experiments and to understand the effect of the column gaps/vertical cracks and the dense layer on the generated stresses in the TBC during thermal cyclic loading through finite element modeling. The experimental results show that the bilayer TBC had significantly higher lifetime than the single-layer TBC. The modeling results show that the dense layer and vertical cracks are beneficial as they reduce the thermally induced stresses which thus increase the lifetime.

  10. Feasibility Assessment of Thermal Barrier Seals for Extreme Transient Temperatures

    Science.gov (United States)

    Steinetz, Bruce M.; Dunlap, Patrick H., Jr.

    1998-01-01

    The assembly joints of modem solid rocket motor cases are generally sealed using conventional O-ring type seals. The 5500+ F combustion gases produced by rocket motors are kept a safe distance away from the seals by thick layers of phenolic insulation. Special compounds are used to fill insulation gaps leading up to the seals to prevent a direct flowpath to them. Design criteria require that the seals should not experience torching or charring during operation, or their sealing ability would be compromised. On limited occasions, NASA has observed charring of the primary O-rings of the Space Shuttle solid rocket nozzle assembly joints due to parasitic leakage paths opening up in the gap-fill compounds during rocket operation. NASA is investigating different approaches for preventing torching or charring of the primary O-rings. One approach is to implement a braided rope seal upstream of the primary O-ring to serve as a thermal barrier that prevents the hot gases from impinging on the O-ring seals. This paper presents flow, resiliency, and thermal resistance for several types of NASA rope seals braided out of carbon fibers. Burn tests were performed to determine the time to burn through each of the seals when exposed to the flame of an oxyacetylene torch (5500 F), representative of the 5500 F solid rocket motor combustion temperatures. Rope seals braided out of carbon fibers endured the flame for over six minutes, three times longer than solid rocket motor burn time. Room and high temperature flow tests are presented for the carbon seals for different amounts of linear compression. Room temperature compression tests were performed to assess seal resiliency and unit preloads as a function of compression. The thermal barrier seal was tested in a subscale "char" motor test in which the seal sealed an intentional defect in the gap insulation. Temperature measurements indicated that the seal blocked 2500 F combustion gases on the upstream side with very little temperature

  11. Mid-Infrared Reflectance Imaging of Thermal-Barrier Coatings

    Science.gov (United States)

    Edlridge, Jeffrey I.; Martin, Richard E.

    2009-01-01

    An apparatus for mid-infrared reflectance imaging has been developed as means of inspecting for subsurface damage in thermal-barrier coatings (TBCs). The apparatus is designed, more specifically, for imaging the progression of buried delamination cracks in plasma-sprayed yttria-stabilized zirconia coatings on turbine-engine components. Progression of TBC delamination occurs by the formation of buried cracks that grow and then link together to produce eventual TBC spallation. The mid-infrared reflectance imaging system described here makes it possible to see delamination progression that is invisible to the unaided eye, and therefore give sufficiently advanced warning before delamination progression adversely affects engine performance and safety. The apparatus (see figure) includes a commercial mid-infrared camera that contains a liquid-nitrogen-cooled focal plane indium antimonide photodetector array, and imaging is restricted by a narrow bandpass centered at wavelength of 4 microns. This narrow wavelength range centered at 4 microns was chosen because (1) it enables avoidance of interfering absorptions by atmospheric OH and CO2 at 3 and 4.25 microns, respectively; and (2) the coating material exhibits maximum transparency in this wavelength range. Delamination contrast is produced in the midinfrared reflectance images because the introduction of cracks into the TBC creates an internal TBC/air-gap interface with a high diffuse reflectivity of 0.81, resulting in substantially higher reflectance of mid-infrared radiation in regions that contain buried delamination cracks. The camera is positioned a short distance (.12 cm) from the specimen. The mid-infrared illumination is generated by a 50-watt silicon carbide source positioned to the side of the mid-infrared camera, and the illumination is collimated and reflected onto the specimen by a 6.35-cm-diameter off-axis paraboloidal mirror. Because the collected images are of a steady-state reflected intensity (in

  12. Thermomechanical behaviour of thermal barrier coatings. Thermal Barrier Coatings II - interim report; Haltbarkeit thermomechanisch belasteter Waermedaemmschichtsysteme. Waermedaemmschichtsysteme II - Zwischenbericht

    Energy Technology Data Exchange (ETDEWEB)

    Berger, C.; Schmidt, A. [Technische Univ. Darmstadt (DE). Inst. fuer Werkstoffkunde (IFW); Scholz, A.; Stamm, W. [Siemens Power AG, Muelheim/Ruhr (Germany)

    2004-07-01

    The thermomechanical behaviour of thermal barrier coatings (TBCs) is being investigated by strain controlled service-type thermomechanical fatigue (TMF) tests in order to simulate creep fatigue life of coatings on gas turbine blades. A first service-type cycle with a cycle period of 20 min, a maximum temperature of 930 C and a minimum temperature of 60 C for industrial gas turbines and a second cycle with a cycle period of 8 min, a maximum temperature of 1050 C and a minimum temperature of 300 C for aero engine gas turbines are applied. A special test technique was developed for hollow test pieces with a component typical wall thickness of 1.8 mm made of a single crystal alloy. Different bondcoats (MCrAIY and PtAI) and an air plasma sprayed (APS-) topcoat as well as electron beam (EB-PVD) topcoat are under investigation. After each specific experiment microstructural investigation is used for damage characterisation. The growth of oxides together with thermal mismatch could be identified as the most important damaging effects. Data from long-term Pre-Oxidation experiments allows to adjust the thickness of the TGO for each specific TMF-experiment. The main objective is to ideal with the influence of different bond coat morphologies on the durability of the thermal barrier coating (TBC-) system. The influence of surface roughness, grain size in the bond coat as well as different bond coats (MCrAIY and PtAI) are investigated. First results show that the surface roughness may have a larger influence on the durability of the TBC-system than initially expected. In order to gain deeper understanding of the damaging mechanisms, finite elements calculations are performed to simulate critical local deformation in the TBC-system. The experiments allow deep insight into the damaging mechanisms governing TBC-systems under service-type conditions and thus are suitable for life time prediction TBC-systems. Although a lot of research has been done on this topic. The influence of

  13. Thermal modelling of various thermal barrier coatings in a high heat flux rocket engine

    Science.gov (United States)

    Nesbitt, James A.

    1989-01-01

    Traditional Air Plasma Sprayed (APS) ZrO2-Y2O3 Thermal Barrier Coatings (TBC's) and Low Pressure Plasma Sprayed (LPPS) ZrO2-Y2O3/Ni-Cr-Al-Y cermet coatings were tested in a H2/O2 rocked engine. The traditional ZrO2-Y2O3 (TBC's) showed considerable metal temperature reductions during testing in the hydrogen-rich environment. A thermal model was developed to predict the thermal response of the tubes with the various coatings. Good agreement was observed between predicted temperatures and measured temperatures at the inner wall of the tube and in the metal near the coating/metal interface. The thermal model was also used to examine the effect of the differences in the reported values of the thermal conductivity of plasma sprayed ZrO2-Y2O3 ceramic coatings, the effect of 100 micron (0.004 in.) thick metallic bond coat, the effect of tangential heat transfer around the tube, and the effect or radiation from the surface of the ceramic coating. It was shown that for the short duration testing in the rocket engine, the most important of these considerations was the effect of the uncertainty in the thermal conductivity of temperatures (greater than 100 C) predicted in the tube. The thermal model was also used to predict the thermal response of the coated rod in order to quantify the difference in the metal temperatures between the two substrate geometries and to explain the previously-observed increased life of coatings on rods over that on tubes. A thermal model was also developed to predict heat transfer to the leading edge of High Pressure Fuel Turbopump (HPFTP) blades during start-up of the space shuttle main engines. The ability of various TBC's to reduce metal temperatures during the two thermal excursions occurring on start-up was predicted. Temperature reductions of 150 to 470 C were predicted for 165 micron (0.0065 in.) coatings for the greater of the two thermal excursions.

  14. Thermal Conductivity and Erosion Durability of Composite Two-Phase Air Plasma Sprayed Thermal Barrier Coatings

    Science.gov (United States)

    Schmitt, Michael P.; Rai, Amarendra K.; Zhu, Dongming; Dorfman, Mitchell R.; Wolfe, Douglas E.

    2015-01-01

    To enhance efficiency of gas turbines, new thermal barrier coatings (TBCs) must be designed which improve upon the thermal stability limit of 7 wt% yttria stabilized zirconia (7YSZ), approximately 1200 C. This tenant has led to the development of new TBC materials and microstructures capable of improved high temperature performance. This study focused on increasing the erosion durability of cubic zirconia based TBCs, traditionally less durable than the metastable t' zirconia based TBCs. Composite TBC microstructures composed of a low thermal conductivity/high temperature stable cubic Low-k matrix phase and a durable t' Low-k secondary phase were deposited via APS. Monolithic coatings composed of cubic Low-k and t' Low-k were also deposited, in addition to a 7YSZ benchmark. The thermal conductivity and erosion durability were then measured and it was found that both of the Low-k materials have significantly reduced thermal conductivities, with monolithic t' Low-k and cubic Low-k improving upon 7YSZ by approximately 13 and approximately 25%, respectively. The 40 wt% t' Low-k composite (40 wt% t' Low-k - 60 wt% cubic Low-k) showed a approximately 22% reduction in thermal conductivity over 7YSZ, indicating even at high levels, the t' Low-k secondary phase had a minimal impact on thermal in the composite coating. It was observed that a mere 20 wt% t' Low-k phase addition can reduce the erosion of a cubic Low-k matrix phase composite coating by over 37%. Various mixing rules were then investigated to assess this non-linear composite behavior and suggestions were made to further improve erosion durability.

  15. Degradation of Thermal Barrier Coatings from Deposits and Its Mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Nitin Padture

    2011-12-31

    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 2Zr{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 interface arresting the penetrating moltenfly- ash front. Additionally, these TBCs were tested using a rig with thermal gradient and simultaneous accumulation of ash. Modeling using an established mechanics model has been performed to illustrate the modes of delamination, as well as further opportunities to optimize coating microstructure. Transfer of the technology was developed in this program to all interested parties.

  16. PLASMA THERMAL BARRIER COATINGS BASED ON ZIRCONIUM DIOXIDE WITH HIGH THERMAL STABILITY

    Directory of Open Access Journals (Sweden)

    O. G. Devoino

    2015-01-01

    Full Text Available The paper presents optimization of  processes for obtaining maximum content of tetragonal phase in the initial material and thermal barrier coatings (TBC based on zirconium dioxide and hafnium oxide.  Results of the investigations on phase composition of oxide HfO2 – ZrO2 – Y2O3  system have been given in the paper. The system represents  a microstructure which is similar to  zirconia dioxide and  transformed for its application at 1300 °C. The paper explains a mechanism of hafnium oxide influence on formation of the given microstructure. The research methodology has been based on complex metallography, X – ray diffraction and electron microscopic investigations of  structural elements of the composite plasma coating HfO2 – ZrO2 – Y2O system.In order to stabilize zirconium dioxide  dopant oxide should not only have an appropriate size of  metal ion, but also form a solid solution with the zirconia. This condition severely limits the number of possible stabilizers. In fact, such stabilization is possible only with the help of rare earth oxides (Y2O3, Yb2O3, CeO2, HfO2. Chemical purity of the applied materials plays a significant role for obtaining high-quality thermal barrier coatings. Hafnium oxide has been selected as powder for thermal barrier coatings instead of zirconium dioxide due to their similarities in structural modification, grating, chemical and physical properties and its high temperature structural transformations. It has been established that plasma thermal barrier HfO2 – ZrO2 – Y2O3 coatings consist of  one tetragonal phase. This phase is equivalent to a non-equilibrium tetragonal t' phase in the “zirconium dioxide stabilized with yttrium oxide” system. Affinity of  Hf+4 and Zr+4 cations leads to the formation of identical metastable phases during rapid quenching.

  17. Environmental/Thermal Barrier Coatings for Ceramic Matrix Composites: Thermal Tradeoff Studies

    Science.gov (United States)

    Murthy, Pappu L. M.; Brewer, David; Shah, Ashwin R.

    2007-01-01

    Recent interest in environmental/thermal barrier coatings (EBC/TBCs) has prompted research to develop life-prediction methodologies for the coating systems of advanced high-temperature ceramic matrix composites (CMCs). Heat-transfer analysis of EBC/TBCs for CMCs is an essential part of the effort. It helps establish the resulting thermal profile through the thickness of the CMC that is protected by the EBC/TBC system. This report documents the results of a one-dimensional analysis of an advanced high-temperature CMC system protected with an EBC/TBC system. The one-dimensional analysis was used for tradeoff studies involving parametric variation of the conductivity; the thickness of the EBC/TBCs, bond coat, and CMC substrate; and the cooling requirements. The insight gained from the results will be used to configure a viable EBC/TBC system for CMC liners that meet the desired hot surface, cold surface, and substrate temperature requirements.

  18. Thermal Fatigue Behavior of Air-Plasma Sprayed Thermal Barrier Coating with Bond Coat Species in Cyclic Thermal Exposure

    Directory of Open Access Journals (Sweden)

    Ungyu Paik

    2013-08-01

    Full Text Available The effects of the bond coat species on the delamination or fracture behavior in thermal barrier coatings (TBCs was investigated using the yclic thermal fatigue and thermal-shock tests. The interface microstructures of each TBC showed a good condition without cracking or delamination after flame thermal fatigue (FTF for 1429 cycles. The TBC with the bond coat prepared by the air-plasma spray (APS method showed a good condition at the interface between the top and bond coats after cyclic furnace thermal fatigue (CFTF for 1429 cycles, whereas the TBCs with the bond coats prepared by the high-velocity oxygen fuel (HVOF and low-pressure plasma spray (LPPS methods showed a partial cracking (and/or delamination and a delamination after 780 cycles, respectively. The TBCs with the bond coats prepared by the APS, HVOF and LPPS methods were fully delaminated (>50% after 159, 36, and 46 cycles, respectively, during the thermal-shock tests. The TGO thickness in the TBCs was strongly dependent on the both exposure time and temperature difference tested. The hardness values were found to be increased only after the CFTF, and the TBC with the bond coat prepared by the APS showed the highest adhesive strength before and after the FTF.

  19. Deterioration of Thermal Barrier Coated Turbine Blades by Erosion

    Directory of Open Access Journals (Sweden)

    Rohan Swar

    2012-01-01

    Full Text Available A combined experimental and computational study was conducted to investigate the erosion of thermal barrier coated (TBC blade surfaces by alumina particles ingestion in a single-stage turbine. In the experimental investigation, tests were performed to determine the erosion rates and particle restitution characteristics under different impact conditions. The experimental results show that the erosion rates increase with increased impingement angle, impact velocity, and temperature. In the computational simulations, an Euler-Lagrangian two-stage approach is used in obtaining numerical solutions to the three-dimensional compressible Reynolds-Averaged Navier-Stokes equations and the particles equations of motion in each blade passage reference frame. User defined functions (UDFs were developed to represent experimentally based correlations for particle surface interaction models and TBC erosion rates models. UDFs were employed in the three-dimensional particle trajectory simulations to determine the particle rebound characteristics and TBC erosion rates on the blade surfaces. Computational results are presented in a commercial turbine and a NASA-designed automotive turbine. The similarities between the erosion patterns in the two turbines are discussed for uniform particle ingestion and for particle ingestion concentrated in the inner and outer 5% of the stator blade span to represent the flow cooling of the combustor liner.

  20. Method of producing a barrier in a thermally insulated container

    Energy Technology Data Exchange (ETDEWEB)

    Collins, M.H.; Le Hardy Guiton, J.D.

    1978-10-17

    The Netherlands' Shell Internationale Research Maatschappij B.V. has developed an essentially pinhole-free barrier for LNG storage/transport tanks. The barrier consists of layers of an expoxy-resin formulation and a glass-fiber material, applied in a special sequence to produce a barrier of superior quality.

  1. Thermal Modelling of Various Thermal Barrier Coatings in a High Flux Rocket Engine

    Science.gov (United States)

    Nesbitt, James A.

    1998-01-01

    A thermal model was developed to predict the thermal response of coated and uncoated tubes tested in a H2/O2 rocket engine. Temperatures were predicted for traditional APS ZrO2-Y2O3 thermal barrier coatings, as well as APS and LPPS ZrO2-Y2O3/NiCrAlY cermet coatings. Good agreement was observed between predicted and measured metal temperatures at locations near the tube surface or at the inner tube wall. The thermal model was also used to quantitatively examine the effect of various coating system parameters on the temperatures in the substrate and coating. Accordingly, the effect of the presence a metallic bond coat and the effect of radiation from the surface of the ceramic layer were examined. In addition, the effect of a variation in the values of the thermal conductivity of the ceramic layer was also investigated. It was shown that a variation in the thermal conductivity of the ceramic layer, on the order of that reported in the literature for plasma sprayed ZrO2-Y2O3 coatings, can result in temperature differences in the substrate greater than 100 C, a much greater effect than that due to the presence of a bond coat or radiation from the ceramic layer. The thermal model was also used to predict the thermal response of a coated rod in order to quantify the difference in the metal temperatures between the two substrate geometries in order to explain the previously-observed increased life of coatings on rods over that on tubes. It was shown that for the short duration testing in the rocket engine, the temperature in a tube could exceed that in a rod by more than 100 C. Lastly, a two-dimensional model was developed to evaluate the effect of tangential heat transfer around the tube and its impact on reducing the stagnation point temperature. It was also shown that tangential heat transfer does not significantly reduce the stagnation point temperature, thus allowing application of a simpler, one-dimensional model for comparing measured and predicted stagnation point

  2. Life modeling of thermal barrier coatings for aircraft gas turbine engines

    Science.gov (United States)

    Miller, R. A.

    1989-01-01

    Thermal barrier coating life models developed under the NASA Lewis Research Center's Hot Section Technology (HOST) Program are summarized. An initial laboratory model and three design-capable models are discussed. Current understanding of coating failure mechanisms are also summarized. The materials and structural aspects of thermal barrier coatings have been successfully integrated under the HOST program to produce models which may now or in the near future be used in design. Efforts on this program continue at Pratt and Whitney Aircraft where their model is being extended to the life prediction of physical vapor deposited thermal barrier coatings.

  3. Thermal Barrier For Vented O-Ring Seal

    Science.gov (United States)

    Schick, H.; Shadlesky, Philip S.; Perry, Mark C.; Ketner, Donald M.; Salita, Mark

    1992-01-01

    Barrier allows gases to seat seal without damaging it. Ring of tungsten-wire mesh forms protective barrier between hot, pressurized combustion gases and O-rings. Mesh cools and depressurizes gases so they safely push on and thereby help to seat primary O-ring or secondary O-ring if primary O-ring fails to form seals. Barrier devised for use in rocket motor. Potential terrestrial applications includes aircraft engines, furnaces, and ducts carrying hot gases.

  4. Low Thermal Conductivity, High Durability Thermal Barrier Coatings for IGCC Environments

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, Eric [Univ. of Connecticut, Storrs, CT (United States); Gell, Maurice [Univ. of Connecticut, Storrs, CT (United States)

    2015-01-15

    Advanced thermal barrier coatings (TBC) are crucial to improved energy efficiency in next generation gas turbine engines. The use of traditional topcoat materials, e.g. yttria-stabilized zirconia (YSZ), is limited at elevated temperatures due to (1) the accelerated undesirable phase transformations and (2) corrosive attacks by calcium-magnesium-aluminum-silicate (CMAS) deposits and moisture. The first goal of this project is to use the Solution Precursor Plasma Spray (SPPS) process to further reduce the thermal conductivity of YSZ TBCs by introducing a unique microstructural feature of layered porosity, called inter-pass boundaries (IPBs). Extensive process optimization accompanied with hundreds of spray trials as well as associated SEM cross-section and laser-flash measurements, yielded a thermal conductivity as low as 0.62 Wm⁻¹K⁻¹ in SPPS YSZ TBCs, approximately 50% reduction of APS TBCs; while other engine critical properties, such as cyclic durability, erosion resistance and sintering resistance, were characterized to be equivalent or better than APS baselines. In addition, modifications were introduced to SPPS TBCs so as to enhance their resistance to CMAS under harsh IGCC environments. Several mitigation approaches were explored, including doping the coatings with Al₂O₃ and TiO₂, applying a CMAS infiltration-inhibiting surface layer, and filling topcoat cracks with blocking substances. The efficacy of all these modifications was assessed with a set of novel CMAS-TBC interaction tests, and the moisture resistance was tested in a custom-built high-temperature moisture rig. In the end, the optimal low thermal conductivity TBC system was selected based on all evaluation tests and its processing conditions were documented. The optimal coating consisted on a thick inner layer of YSZ coating made by the SPPS process having a thermal conductivity 50% lower than standard YSZ coatings topped with a high temperature tolerant CMAS resistant gadolinium

  5. Investigations of thermal barrier coatings of turbine parts using gas flame heating

    Science.gov (United States)

    Lepeshkin, A. R.; Bichkov, N. G.; Ilinskaja, O. I.; Nazarov, V. V.

    2017-09-01

    The development of methods for the calculated and experimental investigations thermal barrier coatings and thermal state of gas-turbine engine parts with a thermal barrier coatings is actual work. The gas flame heating was demonstrated to be effectively used during investigations of a thermal ceramic barrier coatings and thermal state of such gas-turbine engine parts with a TBC as the cooled turbine blades and vanes and combustion liner components. The gas-flame heating is considered to be preferable when investigating the gas-turbine engine parts with a TBC in the special cases when both the convective and radiant components of thermal flow are of great importance. The small-size rig with gas-flame flow made it possible to conduct the comparison investigations with the purpose of evaluating the efficiency of thermal protection of the ceramic deposited thermal barrier coatings on APS and EB techniques. The developed design-experiment method was introduced in bench tests of turbine blades and combustion liner components of gas turbine engines.

  6. Calcium-Magnesium-Aluminosilicate (CMAS) Infiltration and Cyclic Degradations of Thermal and Environmental Barrier Coatings in Thermal Gradients

    Science.gov (United States)

    Zhu, Dongming; Harder, Bryan; Smialek, Jim; Miller, Robert A.

    2014-01-01

    In a continuing effort to develop higher temperature capable turbine thermal barrier and environmental barrier coating systems, Calcium-Magnesium-Aluminosilicate (CMAS) resistance of the advanced coating systems needs to be evaluated and improved. This paper highlights some of NASA past high heat flux testing approaches for turbine thermal and environmental barrier coatings assessments in CMAS environments. One of our current emphases has been focused on the thermal barrier - environmental barrier coating composition and testing developments. The effort has included the CMAS infiltrations in high temperature and high heat flux turbine engine like conditions using advanced laser high heat flux rigs, and subsequently degradation studies in laser heat flux thermal gradient cyclic and isothermal furnace cyclic testing conditions. These heat flux CMAS infiltration and related coating durability testing are essential where appropriate CMAS melting, infiltration and coating-substrate temperature exposure temperature controls can be achieved, thus helping quantify the CMAS-coating interaction and degradation mechanisms. The CMAS work is also playing a critical role in advanced coating developments, by developing laboratory coating durability assessment methodologies in simulated turbine engine conditions and helping establish CMAS test standards in laboratory environments.

  7. Development and Life Prediction of Erosion Resistant Turbine Low Conductivity Thermal Barrier Coatings

    Science.gov (United States)

    Zhu, Dongming; Miller, Robert A.; Kuczmarski, Maria A.

    2010-01-01

    Future rotorcraft propulsion systems are required to operate under highly-loaded conditions and in harsh sand erosion environments, thereby imposing significant material design and durability issues. The incorporation of advanced thermal barrier coatings (TBC) in high pressure turbine systems enables engine designs with higher inlet temperatures, thus improving the engine efficiency, power density and reliability. The impact and erosion resistance of turbine thermal barrier coating systems are crucial to the turbine coating technology application, because a robust turbine blade TBC system is a prerequisite for fully utilizing the potential coating technology benefit in the rotorcraft propulsion. This paper describes the turbine blade TBC development in addressing the coating impact and erosion resistance. Advanced thermal barrier coating systems with improved performance have also been validated in laboratory simulated engine erosion and/or thermal gradient environments. A preliminary life prediction modeling approach to emphasize the turbine blade coating erosion is also presented.

  8. Monitoring thermally grown oxides under thermal barrier coatings using photoluminescence piezospectroscopy (PLPS)

    Energy Technology Data Exchange (ETDEWEB)

    Del Corno, A.; De Maria, L.; Rinaldi, C. [ERSE, Milan (Italy); Nalin, L.; Simms, N.J. [Cranfield Univ., Bedford (United Kingdom). Energy Technology Centre

    2010-07-01

    The use of thermal barrier coatings (TBCs) on cooled components in industrial gas turbine has enabled higher inlet gas temperatures to be used and hence higher efficiencies to be achieved, without increasing component metal temperatures. However TBCs have a complex coating structure that during high temperature exposure and thermal cycling modifies until TBC spalling which can result in dangerous over-heating of components. This paper reports the results of a TBC exposure programme planned to monitor TGOs development in an example TBC system in terms of both stress evolution within the TGOs and TGO growth. The COST538 reference TBC system was used: an yttria stabilised zirconia TBC applied to an Amdry 995 bond coat on an CMSX-4 substrate. Samples were in the form of 10 mm diameter bars, with the TBC applied to their curved surface. Coated samples were exposed in simulated combustion gases at temperatures 850, 900 and 950 C for periods of up to 10,000 hours. Every 1000 hours samples were cooled and weighed to monitor the progression of the oxidation: selected samples NDT inspected using PLPS and/or destructive examination. Cross-sections were prepared and examined in a scanning electron microscope (SEM) at multiple locations to determine TGO thickness distributions. PLPS spectra were measured and elaborated with a system self developed in ERSE, able to calculate and map the TGO residual stress values under columnar TBCs. So the positions could be evidenced where the damage of the TBC /TGO/BC interface is higher on the exposed bars. The data of TGO thickness distributions and PLPS stress measurement distributions were compared to the exposures carried out on samples to identify and quantify trends in their development. Metallography confirmed that the PLPs technique can reliably detect interface cracking before visible EB-PVD TBC spalling. (orig.)

  9. Human plan of capital of Westinghouse; Plan de capital humano de Westinghouse

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, B.; Gutierrez Elso, J. E.

    2008-07-01

    After three decades of nuclear standstill, the Nuclear Renaissance resulted in a changing environment, Nuclear Companies should prepare and adapt to different challenges: the fast growing of the organization, the loss of talent to other more attractive industrial fields and the transfer and management of knowledge to young engineers that have not participated in the building of nuclear plants. In this article different Westinghouse initiatives in this respect are commented. (Author)

  10. SELECTION OF OXIDES FOR STABILIZATION OF ZIRCONIUM DIOXIDE WHILE OBTAINING THERMAL BARRIER COATINGS

    Directory of Open Access Journals (Sweden)

    V. V. Okovity

    2015-01-01

    Full Text Available The paper analyzes selection of oxides and describes in details a majority of oxide systems which are applicable for stabilization of zirconium dioxide while obtaining thermal barrier coatings with maximum amount of tetragonal phase. Methodology of investigation is based on a review of analytical information on the current state of thermal barrier coatings on the basis of zirconium dioxide stabilized by oxides of rare-earth metals. The method used for application of  zirconium dioxide thermal barrier coatings is plasma spraying. Positive results have been also obtained while applying e-beam sputtering, ion-plasma deposition and magnetron sputtering. Nevertheless preferred plasma spraying application for thermal barrier coatings still continues due to its high productivity and versatility that permits to deposit metallic and ceramic materials of the ordered chemical and phase composition.Ytterbium and cerium oxides have been selected as oxides for stabilization of zirconium dioxide in order to obtain thermal barrier coatings. The paper also considers аn oxide system of zirconium dioxide: “hafnium oxide – yttrium oxide”, representing in itself the structure which is similar to zirconium dioxide.

  11. Functionally gradient materials for thermal barrier coatings in advanced gas turbine systems

    Energy Technology Data Exchange (ETDEWEB)

    Banovic, S.W.; Barmak, K.; Chan, H.M. [Lehigh Univ., Bethlehem, PA (United States)] [and others

    1995-10-01

    New designs for advanced gas turbine engines for power production are required to have higher operating temperatures in order to increase efficiency. However, elevated temperatures will increase the magnitude and severity of environmental degradation of critical turbine components (e.g. combustor parts, turbine blades, etc{hor_ellipsis}). To offset this problem, the usage of thermal barrier coatings (TBCs) has become popular by allowing an increase in maximum inlet temperatures for an operating engine. Although thermal barrier technology is over thirty years old, the principle failure mechanism is the spallation of the ceramic coating at or near the ceramic/bond coat interface. Therefore, it is desirable to develop a coating that combines the thermal barrier qualities of the ceramic layer and the corrosion protection by the metallic bond coat without the detrimental effects associated with the localization of the ceramic/metal interface to a single plane.

  12. Thermal insulating barrier and neutron shield providing integrated protection for a nuclear reactor vessel

    Science.gov (United States)

    Schreiber, Roger B.; Fero, Arnold H.; Sejvar, James

    1997-01-01

    The reactor vessel of a nuclear reactor installation which is suspended from the cold leg nozzles in a reactor cavity is provided with a lower thermal insulating barrier spaced from the reactor vessel to form a chamber which can be flooded with cooling water through passive valving to directly cool the reactor vessel in the event of a severe accident. The passive valving also includes bistable vents at the upper end of the thermal insulating barrier for releasing steam. A removable, modular neutron shield extending around the upper end of the reactor cavity below the nozzles forms with the upwardly and outwardly tapered transition on the outer surface of the reactor vessel, a labyrinthine channel which reduces neutron streaming while providing a passage for the escape of steam during a severe accident, and for the cooling air which is circulated along the reactor cavity walls outside the thermal insulating barrier during normal operation of the reactor.

  13. Saturated Resin Ectopic Regeneration by Non-Thermal Dielectric Barrier Discharge Plasma

    OpenAIRE

    Chunjing Hao; Zehua Xiao; Di Xu; Chengbo Zhang; Jian Qiu; Kefu Liu

    2017-01-01

    Textile dyes are some of the most refractory organic compounds in the environment due to their complex and various structure. An integrated resin adsorption/Dielectric Barrier Discharge (DBD) plasma regeneration was proposed to treat the indigo carmine solution. It is the first time to report ectopic regeneration of the saturated resins by non-thermal Dielectric Barrier Discharge. The adsorption/desorption efficiency, surface functional groups, structural properties, regeneration efficiency, ...

  14. Mechanical, thermal, and barrier properties of methylcellulose/cellulose nanocrystals nanocomposites

    Directory of Open Access Journals (Sweden)

    Hudson Alves Silvério

    2014-12-01

    Full Text Available In this work, the effects of incorporating cellulose nanocrystals from soy hulls (WSH30 on the mechanical, thermal, and barrier properties of methylcellulose (MC nanocomposites were evaluated. MC/WSH30 nanocomposite films with different filler levels (2, 4, 6, 8, and 10% were prepared by casting. Compared to neat MC film, improvements in the mechanical and barrier properties were observed, while thermal stability was retained. The improved mechanical properties of nanocomposites prepared may be attributed to mechanical percolation of WSH30, formation of a continuous network of WSH30 linked by hydrogen interactions and a close association between filler and matrix.

  15. Potential benefits of a ceramic thermal barrier coating on large power generation gas turbine

    Science.gov (United States)

    Clark, J. S.; Nainiger, J. J.

    1977-01-01

    Thermal barrier coating design option offers benefit in terms of reduced electricity costs when used in utility gas turbines. Options considered include: increased firing temperature, increased component life, reduced cooling air requirements, and increased corrosion resistance (resulting in increased tolerance for dirty fuels). Performance and cost data were obtained. Simple, recuperated and combined cycle applications were considered, and distillate and residual fuels were assumed. The results indicate that thermal barrier coatings could produce large electricity cost savings if these coatings permit turbine operation with residual fuels at distillate-rated firing temperatures. The results also show that increased turbine inlet temperature can result in substantial savings in fuel and capital costs.

  16. Mechanical, thermal, and barrier properties of methylcellulose/cellulose nanocrystals nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Silverio, Hudson Alves; Flauzino Neto, Wilson Pires; Silva, Ingrid Souza Vieira da; Rosa, Joyce Rover; Pasquini, Daniel, E-mail: pasquini@iqufu.ufu.br, E-mail: danielpasquini2005@yahoo.com.br [Universidade de Uberlandia (USU), MG (Brazil). Instituto de Quimica; Assuncao, Rosana Maria Nascimento de [Universidade de Uberlandia (USU), Ituiutaba, MG (brazil). Fac. de Ciencias Integradas do Pontal; Barud, Hernane da Silva; Ribeiro, Sidney Jose Lima [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Araraquara, SP (Brazil). Instituto de Quimica

    2014-11-15

    In this work, the effects of incorporating cellulose nanocrystals from soy hulls (WSH{sub 30}) on the mechanical, thermal, and barrier properties of methylcellulose (MC) nanocomposites were evaluated. MC/WSH{sub 30} nanocomposite films with different filler levels (2, 4, 6, 8, and 10%) were prepared by casting. Compared to neat MC film, improvements in the mechanical and barrier properties were observed, while thermal stability was retained. The improved mechanical properties of nanocomposites prepared may be attributed to mechanical percolation of WSH{sub 30}, formation of a continuous network of WSH{sub 30} linked by hydrogen interactions and a close association between filler and matrix. (author)

  17. Barriers to the Diffusion of Solar Thermal Technologies

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    Despite its considerable potential in household, domestic and industry sectors, the possible contribution of solar heat is often neglected in many academic and institutional energy projections and scenarios. This is best explained by the frequent failure to distinguish heat and work as two different forms of energy transfers. As a result, policy makers in many countries or States have tended to pay lesser attention to solar thermal technologies than to other renewable energy technologies.

  18. Investigation on the Interface Characteristics of the Thermal Barrier Coating System through Flat Cylindrical Indenters

    Directory of Open Access Journals (Sweden)

    Shifeng Wen

    2014-01-01

    Full Text Available Thermal barrier coating (TBC systems are highly advanced material systems and usually applied to insulate components from large and prolonged heat loads by utilizing thermally insulating materials. In this study, the characteristics of the interface of thermal barrier coating systems have been simulated by the finite-element method (FEM. The emphasis was put on the stress distribution at the interface which is beneath the indenter. The effect of the interface roughness, the thermally grown oxide (TGO layer's thickness, and the modulus ratio (η of the thin film with the substrate has been considered. Finite-element results showed that the influences of the interface roughness and the TGO layer's thickness on stress distribution were important. At the same time, the residual stress distribution has been investigated in detail.

  19. Oxidation and thermal shock behavior of thermal barrier coated 18/10CrNi alloy with coating modifications

    Energy Technology Data Exchange (ETDEWEB)

    Guergen, Selim [Vocational School of Transportation, Anadolu University, Eskisehir (Turkmenistan); Diltemiz, Seyid Fehmi [Turkish Air Force1st Air Supply and Maintenance Center Command, Eskisehir (Turkmenistan); Kushan, Melih Cemal [Dept. of Mechanical Engineering, Eskisehir Osmangazi University, Eskisehir (Turkmenistan)

    2017-01-15

    In this study, substrates of 18/10CrNi alloy plates were initially sprayed with a Ni-21Cr-10Al-1Y bond coat and then with an yttria stabilized zirconia top coat by plasma spraying. Subsequently, plasma-sprayed Thermal barrier coatings (TBCs) were treated with two different modification methods, namely, vacuum heat treatment and laser glazing. The effects of modifications on the oxidation and thermal shock behavior of the coatings were evaluated. The effect of coat thickness on the bond strength of the coats was also investigated. Results showed enhancement of the oxidation resistance and thermal shock resistance of TBCs following modifications. Although vacuum heat treatment and laser glazing exhibited comparable results as per oxidation resistance, the former generated the best improvement in the thermal shock resistance of the TBCs. Bond strength also decreased as coat thickness increased.

  20. INFLUENCE OF THERMAL BARRIER TYPE CERAMIC LAYER’S CHEMICAL COMPOSITION AND QUICK THERMAL SCHOCK ON THEIR POROSITY AND ADHERENCE

    Directory of Open Access Journals (Sweden)

    Florin Ciofu

    2011-07-01

    Full Text Available The paper presents several types of thermal barrier type ceramic layers and the variations concerningtheir porosity and adherence related with their chemical composition. The structural and compositionalcharacterization of the obtained layers was performed by electron microscopy, one of the most relevantinvestigation methods in order to choose the optimum composition for the external layer deposited on copperdevices. The effect of quick thermal shock on the samples porosity and on chemical elements distribution alongthe layer’s thickness was also taken into account.

  1. Standardized Technical Specifications for Westinghouse PWRs

    Energy Technology Data Exchange (ETDEWEB)

    1978-06-15

    This Standard Technical Specification (STS) has been structured for the broadest possible use on Westinghouse plants currently being reviewed for an Operating License. Accordingly, the document contains specifications applicable to plants (1) with either 3 or 4 loops and (2) with and without loop stop valves. In addition, four separate and discrete containment specification sections are provided for each of the following containment types: Atmospheric, Ice Condenser, Sub-Atmospheric, and Dual. Optional specifications are provided for those features and systems which may be included in individual plant designs but are not generic in their scope of application. Alternate specifications are provided in a limited number of cases to cover situations where alternate specification requirements are necessary on a generic basis because of design differences. The format of the STS addresses the categories required by 10 CFR 50 and consists of six sections covering the areas of: Definitions, Safety Limits and Limiting Safety System Settings, Limiting Conditions for Operation, Surveillance Requirements, Design Features, and Administrative Controls.

  2. Loadings in thermal barrier coatings of jet engine turbine blades an experimental research and numerical modeling

    CERN Document Server

    Sadowski, Tomasz

    2016-01-01

    This book discusses complex loadings of turbine blades and protective layer Thermal Barrier Coating (TBC), under real working airplane jet conditions. They obey both multi-axial mechanical loading and sudden temperature variation during starting and landing of the airplanes. In particular, two types of blades are analyzed: stationary and rotating, which are widely applied in turbine engines produced by airplane factories.

  3. Current status and future trends in turbine application of thermal barrier coatings

    Science.gov (United States)

    Sheffler, Keith D.; Gupta, Dinesh K.

    1988-01-01

    This paper provides an overview of the current status and future trends in application of thermal barrier coatings (TBC) to turbine components, and in particular to high turbine airfoils. Included are descriptions of the favorable results achieved to date with bill-of-material applications of plasma deposited TBC, and recent experience with developmental coatings applied by electron beam-physical vapor deposition.

  4. Progress toward life modeling of thermal barrier coatings for aircraft gas turbine engines

    Science.gov (United States)

    Miller, R. A.

    1987-01-01

    Progress toward developing life models for simulating the behavior of thermal barrier coatings in aircraffft gas turbine engines is discussed. A preliminary laboratory model is described as are current efforts to develop engine-capable models. Current understanding of failure mechanisms is also summarized.

  5. GaN on Diamond with Ultra-Low Thermal Barrier Resistance

    Science.gov (United States)

    2016-03-31

    GaN-on-Diamond with Ultra -Low Thermal Barrier Resistance Xing Gu1, Cathy Lee1, Jinqiao Xie1, Edward Beam1, Michael Becker2, Timothy A. Grotjohn2...previously reported best data, and close to the limit predicted by theoretical models for GaN-diamond interfaces Keywords: GaN-on-Diamond; ultra -low...is yet to be realized, mainly due to thermal limitations. Diamond, which offers superior thermal conductivity of ~ 2000 W/ mK , is a natural choice

  6. A combined approach for determining the thermal performance of radiant barriers under field conditions

    Energy Technology Data Exchange (ETDEWEB)

    Miranville, Frederic; Boyer, Harry; Lauret, Philippe; Lucas, Franck [University of La Reunion, Building and Systems Physics Laboratory, 117 rue du General Ailleret, 97 430 Le Tampon (France)

    2008-05-15

    This paper deals with a combined approach for assessing the thermal performance of radiant barriers under field conditions, based both on dynamic simulations and field measurements. The methodology involves the combination of model predictions and experimental results of a complex roof including a radiant barrier installed on a dedicated test cell. During the empirical validation of the building thermal model and more particularly thanks to the results of sensitivity analysis, simplifications of the model were made. These considerations lead to successive simplified versions of the model and finally a very simplified one, which is used to determine the thermal resistance of the complex roof. We first present the detailed thermal model, elaborated with a prototype of building simulation code. We then describe the experimental test cell and put the emphasis on the details of the roof. The simplification of the detailed model is then explained and the results presented. A value of the thermal resistance is finally obtained and confirms the potential of radiant barriers for a tropical climate. (author)

  7. Flyweight 3D Graphene Scaffolds with Microinterface Barrier-Derived Tunable Thermal Insulation and Flame Retardancy.

    Science.gov (United States)

    Zhang, Qiangqiang; Hao, Menglong; Xu, Xiang; Xiong, Guoping; Li, Hui; Fisher, Timothy S

    2017-04-26

    In this article, flyweight three-dimensional (3D) graphene scaffolds (GSs) have been demonstrated with a microinterface barrier-derived thermal insulation and flame retardancy characteristics. Such 3D GSs were fabricated by a modified hydrothermal method and a unidirectional freeze-casting process with hierarchical porous microstructures. Because of high porosity (99.9%), significant phonon scattering, and strong π-π interaction at the interface barriers of multilayer graphene cellular walls, the GSs demonstrate a sequence of multifunctional properties simultaneously, such as lightweight density, thermal insulating characteristics, and outstanding mechanical robustness. At 100 °C, oxidized GSs exhibit a thermal conductivity of 0.0126 ± 0.0010 W/(m K) in vacuum. The thermal conductivity of oxidized GSs remains relatively unaffected despite large-scale deformation-induced densification of the microstructures, as compared to the behavior of reduced GSs (rGSs) whose thermal conductivity increases dramatically under compression. The contrasting behavior of oxidized GSs and rGSs appears to derive from large differences in the intersheet contact resistance and varying intrinsic thermal conductivity between reduced and oxidized graphene sheets. The oxidized GSs also exhibit excellent flame retardant behavior and mechanical robustness, with only 2% strength decay after flame treatment. In a broader context, this work demonstrates a useful strategy to design porous nanomaterials with a tunable heat conduction behavior through interface engineering at the nanoscale.

  8. Process sensitivity studies of the Westinghouse sulfur cycle for hydrogen generation

    Science.gov (United States)

    Carty, R. H.; Cox, K. E.; Funk, J. E.; Soliman, M. A.; Conger, W. L.; Brecher, L. E.; Spewock, S.

    1976-01-01

    The effect of variations of acid concentration, pressure, and temperature on the thermal process efficiency of the Westinghouse sulfur cycle was examined using the HYDRGN program. Modifications to the original program were made to duplicate the process flowsheet and take into account combined cycle heat-to-work efficiencies for electrochemical work requirements, aqueous solutions, and heat-of-mixing effects. A total of 125 process variations were considered (acid concentration: 50-90 w/o; pressure: 15-750 psia; temperature: 922K - 1366K). The methods of analysis, results, and conclusions are presented.

  9. Westinghouse Integrated Control and Instrumentation System in Sizewell B

    Energy Technology Data Exchange (ETDEWEB)

    Kang, S.; Bordelon, F. [Westinghouse Electric Corporation, Pennsylvania (United States)

    1993-04-15

    The Westinghouse supplied control and instrumentation system for the Sizewell B Station in the United Kingdom is the first implementation of the state-of-art digital control technology in an integrated plant-wide protection, control and information system in a nuclear power plant. The system is comprised of four primary functions - control room, data processing and display generation, control and protection, and plant process. The total system is subdivided into two primary system, Primary Protection System (PPS) and Integrated System for Centralized Operation (W-IMCO). PPS is micro-processor based Westinghouse Eagle Series equipment based on 4 redundant channels of measured input, signal processing and conditioning, Trip demands and Engineered Safety Features actuation (Trip/ESA). Witco is comprised of the High Integrity Control System (Hicks), the Process Control System (P/CAS) and the Distributed Computer System (DDS). PPS and W-IMCO are organized in hierarchy to meet the all the functions of measurement, control and Man Machine Interface (Mi) functions for the safe and efficient operation of the plant. The PPS and Witco are based entirely upon well proven Westinghouse I and C products, PPS and Hicks with Eagle Series equipment, P/CAS and DES with Westinghouse-standard Westinghouse Distributed Processor Family (WDPF) equipment. This integrated system approach where the functional design is logically separated from the equipment configuration allowed plant construction, I and C design and manufacturing to proceed in parallel.

  10. Synthesis of thermal and chemical resistant oxygen barrier starch with reinforcement of nano silicon carbide.

    Science.gov (United States)

    Dash, Satyabrata; Swain, Sarat K

    2013-09-12

    Starch/silicon carbide (starch/SiC) bionanocomposites were synthesized by solution method using different wt% of silicon carbide with starch matrix. The interaction between starch and silicon carbide was studied by Fourier transform infrared (FTIR) spectroscopy. The structure of the bionanocomposites was investigated by X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM). Thermal property of starch/SiC bionanocomposites was measured and a significant enhancement of thermal resistance was noticed. The oxygen barrier property of the composites was studied and a substantial reduction in permeability was observed as compared to the virgin starch. The reduction of oxygen permeability with enhancement of thermal stability of prepared bionanocomposites may enable the materials suitable for thermal resistant packaging and adhesive applications. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Development of reliable thermal barrier coatings for high-loaded turbine and combustor parts

    Energy Technology Data Exchange (ETDEWEB)

    Bossmann, Hans-Peter; Witz, Gregoire; Baumann, Robert [Alstom (Switzerland) Ltd., Baden (Switzerland)

    2011-07-01

    Thermal Barrier Coatings (TBC), mainly consisting of 7 % Yttria stabilised Zirconia (7YSZ), have been used for decades in gas turbines. A variety of MCrAIY have been developed as bondcoat (BC), where M represents Ni, Co or a combination of both. Further elements have been added to improve BC behaviour. For application of BC/TBC, thermal spraying of fine metallic/ceramic powder is state of the art. TBC is applied by atmospheric plasma spraying (APS), BC either by vacuum or low pressure plasma spraying or APS. (orig.)

  12. History of Thermal Barrier Coatings for Gas Turbine Engines: Emphasizing NASA's Role from 1942 to 1990

    Science.gov (United States)

    Miller, Robert A.

    2009-01-01

    NASA has played a central role in the development of thermal barrier coatings (TBCs) for gas turbine applications. This report discusses the history of TBCs emphasizing the role NASA has played beginning with (1) frit coatings in the 1940s and 1950s; (2) thermally sprayed coatings for rocket application in the 1960s and early 1970s; (3) the beginnings of the modern era of turbine section coatings in the mid 1970s; and (4) failure mechanism and life prediction studies in the 1980s and 1990s. More recent efforts are also briefly discussed.

  13. Blanch Resistant and Thermal Barrier NiAl Coating Systems for Advanced Copper Alloys

    Science.gov (United States)

    Raj, Sai V. (Inventor)

    2005-01-01

    A method of forming an environmental resistant thermal barrier coating on a copper alloy is disclosed. The steps include cleansing a surface of a copper alloy, depositing a bond coat on the cleansed surface of the copper alloy, depositing a NiAl top coat on the bond coat and consolidating the bond coat and the NiAl top coat to form the thermal barrier coating. The bond coat may be a nickel layer or a layer composed of at least one of copper and chromium-copper alloy and either the bond coat or the NiAl top coat or both may be deposited using a low pressure or vacuum plasma spray.

  14. Expanding of the fatigue life of thermal barrier coating by mixing MoSl{sub 2} to thermal sprayed layer

    Energy Technology Data Exchange (ETDEWEB)

    Sonoya, K. [Ishikawajima-Harima Heavy Industries Co. Ltd., Yokohama (Japan); Tobe, S. [Ashikaga Inst. of Tech., Ashikaga-shi, Tochigi-ken (Japan)

    2000-07-01

    Recent trends of turbine blades of advanced aircraft gas turbine engines are to increase output power of the engines, to increase engine efficiency and to reduce environmental emission, and thus, higher operating temperatures of the engines are required. One of the technologies for increasing the operating temperature is a thermal barrier splayed coating [1,2]. The coating usually consists of a bonding coating layer of an alloy of NiCrAlY on the turbine blade and a top layer of ZrO{sub 2}-Y{sub 2}O{sub 3}, namely, partially stabilized zirconia (PSZ). However, conventional coating systems deteriorate during turbine operation due to thermal and mechanical stresses imposed and corrosion actions by combustion gas coming from combustion chambers. Thus, the main issue is to develop measures against high oxidation rate and low fatigue life of the bonding coating layer. An idea for enhancing oxidation resistance and fatigue life as well of thermal barrier coatings consisting of a zirconia-based coating is to provide with a self-healing capability to the coating by diffusing a suitable substance to fatigue crack surfaces formed in the coating. Excessive oxidation of the NiCrAlY layer beneath is prevented for extending fatigue life of the splayed barrier coating. Several investigations have been conducted on the matter, and a research paper [3] claims that MoSi{sub 2} in a splayed coating has a self-healing capability for cracks formed in the coating by embedding the cracks with SiO{sub 2} formed from MoSi{sub 2} at high temperatures. Thus, a new coating system containing NiCrAlY, MoSi{sub 2}, and PSZ is expected to be developed instead of a two-layer coating system of NiCrAlY and PSZ.

  15. Novel Functionally Graded Thermal Barrier Coatings in Coal-Fired Power Plant Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jing [Indiana Univ., Indianapolis, IN (United States)

    2016-11-01

    This project presents a detailed investigation of a novel functionally graded coating material, pyrochlore oxide, for thermal barrier coating (TBC) in gas turbines used in coal-fired power plants. Thermal barrier coatings are refractory materials deposited on gas turbine components, which provide thermal protection for metallic components at operating conditions. The ultimate goal of this research is to develop a manufacturing process to produce the novel low thermal conductivity and high thermal stability pyrochlore oxide based coatings with improved high-temperature durability. The current standard TBC, yttria stabilized zirconia (YSZ), has service temperatures limited to <1200°C, due to sintering and phase transition at higher temperatures. In contrast, pyrochlore oxide, e.g., lanthanum zirconate (La2Zr2O7, LZ), has demonstrated lower thermal conductivity and better thermal stability, which are crucial to high temperature applications, such as gas turbines used in coal-fired power plants. Indiana University – Purdue University Indianapolis (IUPUI) has collaborated with Praxair Surface Technologies (PST), and Changwon National University in South Korea to perform the proposed research. The research findings are critical to the extension of current TBCs to a broader range of high-temperature materials and applications. Several tasks were originally proposed and accomplished, with additional new opportunities identified during the course of the project. In this report, a description of the project tasks, the main findings and conclusions are given. A list of publications and presentations resulted from this research is listed in the Appendix at the end of the report.

  16. The oxidation behavior of classical thermal barrier coatings exposed to extreme temperature

    Directory of Open Access Journals (Sweden)

    Alina DRAGOMIRESCU

    2017-03-01

    Full Text Available Thermal barrier coatings (TBC are designed to protect metal surfaces from extreme temperatures and improve their resistance to oxidation during service. Currently, the most commonly used systems are those that have the TBC structure bond coat (BC / top coat (TC layers. The top coat layer is a ceramic layer. Oxidation tests are designed to identify the dynamics of the thermally oxide layer (TGO growth at the interface of bond coat / top coat layers, delamination mechanism and the TBC structural changes induced by thermal conditions. This paper is a short study on the evolution of aluminum oxide protective layer along with prolonged exposure to the testing temperature. There have been tested rectangular specimens of metal super alloy with four surfaces coated with a duplex thermal barrier coating system. The specimens were microscopically and EDAX analyzed before and after the tests. In order to determine the oxide type, the samples were analyzed using X-ray diffraction. The results of the investigation are encouraging for future studies. The results show a direct relationship between the development of the oxide layer and long exposure to the test temperature. Future research will focus on changing the testing temperature to compare the results.

  17. Multilayer Thermal Barrier Coating (TBC) Architectures Utilizing Rare Earth Doped YSZ and Rare Earth Pyrochlores

    Science.gov (United States)

    Schmitt, Michael P.; Rai, Amarendra K.; Bhattacharya, Rabi; Zhu, Dongming; Wolfe, Douglas E.

    2014-01-01

    To allow for increased gas turbine efficiencies, new insulating thermal barrier coatings (TBCs) must be developed to protect the underlying metallic components from higher operating temperatures. This work focused on using rare earth doped (Yb and Gd) yttria stabilized zirconia (t' Low-k) and Gd2Zr2O7 pyrochlores (GZO) combined with novel nanolayered and thick layered microstructures to enable operation beyond the 1200 C stability limit of current 7 wt% yttria stabilized zirconia (7YSZ) coatings. It was observed that the layered system can reduce the thermal conductivity by approximately 45 percent with respect to YSZ after 20 hr of testing at 1316 C. The erosion rate of GZO is shown to be an order to magnitude higher than YSZ and t' Low-k, but this can be reduced by almost 57 percent when utilizing a nanolayered structure. Lastly, the thermal instability of the layered system is investigated and thought is given to optimization of layer thickness.

  18. Very Tough, Erosion-Resistant Turbine Airfoil Thermal Barrier Coatings Developed

    Science.gov (United States)

    Zhu, Dong-Ming; Miller, Robert A.

    2005-01-01

    Ceramic thermal barrier coatings (TBCs) are receiving increased attention for advanced gas turbine engine applications. These coatings are considered to be technologically important because of their ability to further increase engine operating temperatures and reduce cooling requirements, thus achieving higher engine efficiency, lower emissions, and increased performance goals. To take full advantage of the capabilities of these coatings, researchers need to use an aggressive design approach whenever possible--one that allows greater temperature reductions through the coating systems and less cooling air to the components. Advanced TBCs that have significantly lower thermal conductivity and better thermal stability than current coatings have been developed for future ultra-efficient, low-emission engine systems. Multicomponent-doped, defect-clustered TBCs have been shown to offer the low conductivity and high stability required for future high-temperature engine applications.

  19. Symbiotic bacterial communities of corals across two thermally distinct environments on the Belize Barrier Reef System

    Science.gov (United States)

    Speare, L.

    2016-02-01

    Corals maintain symbiotic relationships with complex communities of algae, other eukaryotes, and bacteria, collectively called the `holobiont'. Studies suggest that differences in bacterial communities may affect coral holobiont nutrition, defense capabilities, and susceptibility to disease. Using next-generation metabarcoding of the 16S rRNA we will examine how bacterial communities differ between three coral host species (Siderastrea siderea, S. radians, and Pseudodiploria strigosa) from two distinct thermal environments of the Belize Barrier Reef System. These thermal environments differ in both mean annual temperature and thermal variation characterized here as: 1) `extreme' sites exhibiting high mean temperatures and high thermal variation, and 2) `low' sites exhibiting low mean temperatures and low thermal variation. Our results will help elucidate the complex dynamics that exist between coral-specific bacterial communities across different thermal environments. Characterizing the bacterial component of the coral holobiont can help us better recognize how species-level differences may affect overall holobiont physiology across a range of temperatures and lead to a more thorough understanding of coral disease susceptibility and overall fitness.

  20. Development of Reliability Based Life Prediction Methods for Thermal and Environmental Barrier Coatings in Ceramic Matrix Composites

    Science.gov (United States)

    Shah, Ashwin

    2001-01-01

    Literature survey related to the EBC/TBC (environmental barrier coating/thermal barrier coating) fife models, failure mechanisms in EBC/TBC and the initial work plan for the proposed EBC/TBC life prediction methods development was developed as well as the finite element model for the thermal/stress analysis of the GRC-developed EBC system was prepared. Technical report for these activities is given in the subsequent sections.

  1. Westinghouse independent safety review of Savannah River production reactors

    Energy Technology Data Exchange (ETDEWEB)

    Leggett, W.D.; McShane, W.J. (Westinghouse Hanford Co., Richland, WA (USA)); Liparulo, N.J.; McAdoo, J.D.; Strawbridge, L.E. (Westinghouse Electric Corp., Pittsburgh, PA (USA). Nuclear and Advanced Technology Div.); Toto, G. (Westinghouse Electric Corp., Pittsburgh, PA (USA). Nuclear Services Div.); Fauske, H.K. (Fauske and Associates, Inc., Burr Ridge, IL (USA)); Call, D.W. (Westinghouse Savannah R

    1989-04-01

    Westinghouse Electric Corporation has performed a safety assessment of the Savannah River production reactors (K,L, and P) as requested by the US Department of Energy. This assessment was performed between November 1, 1988, and April 1, 1989, under the transition contract for the Westinghouse Savannah River Company's preparations to succeed E.I. du Pont de Nemours Company as the US Department of Energy contractor for the Savannah River Project. The reviewers were drawn from several Westinghouse nuclear energy organizations, embody a combination of commercial and government reactor experience, and have backgrounds covering the range of technologies relevant to assessing nuclear safety. The report presents the rationale from which the overall judgment was drawn and the basis for the committee's opinion on the phased restart strategy proposed by E.I. du Pont de Nemours Company, Westinghouse, and the US Department of Energy-Savannah River. The committee concluded that it could recommend restart of one reactor at partial power upon completion of a list of recommended upgrades both to systems and their supporting analyses and after demonstration that the organization had assimilated the massive changes it will have undergone.

  2. Root cause of incomplete control rod insertions at Westinghouse reactors

    Energy Technology Data Exchange (ETDEWEB)

    Ray, S. [Westinghouse, Monroeville, PA (United States)

    1997-01-01

    Within the past year, incomplete RCCA insertions have been observed on high burnup fuel assemblies at two Westinghouse PWRs. Initial tests at the Wolf Creek site indicated that the direct cause of the incomplete insertions observed at Wolf Creek was excessive fuel assembly thimble tube distortion. Westinghouse committed to the NRC to perform a root cause analysis by the end of August, 1996. The root cause analysis process used by Westinghouse included testing at ten sites to obtain drag, growth and other characteristics of high burnup fuel assemblies. It also included testing at the Westinghouse hot cell of two of the Wolf Creek incomplete insertion assemblies. A mechanical model was developed to calculate the response of fuel assemblies when subjected to compressive loads. Detailed manufacturing reviews were conducted to determine if this was a manufacturing related issue. In addition, a review of available worldwide experience was performed. Based on the above, it was concluded that the thimble tube distortion observed on the Wolf Creek incomplete insertion assemblies was caused by unusual fuel assembly growth over and above what would typically be expected as a result of irradiation exposure. It was determined that the unusual growth component is a combination of growth due to oxide accumulation and accelerated growth, and would only be expected in high temperature plants on fuel assemblies that see long residence times and high power duties.

  3. Thermal Cycling and High-Temperature Corrosion Tests of Rare Earth Silicate Environmental Barrier Coatings

    Science.gov (United States)

    Darthout, Émilien; Gitzhofer, François

    2017-12-01

    Lutetium and yttrium silicates, enriched with an additional secondary zirconia phase, environmental barrier coatings were synthesized by the solution precursor plasma spraying process on silicon carbide substrates. A custom-made oven was designed for thermal cycling and water vapor corrosion testing. The oven can test four specimens simultaneously and allows to evaluate environmental barrier performances under similar corrosion kinetics compared to turbine engines. Coatings structural evolution has been observed by SEM on the polished cross sections, and phase composition has been analyzed by XRD. All coatings have been thermally cycled between 1300 °C and the ambient temperature, without spallation, due to their porosity and the presence of additional secondary phase which increases the thermal cycling resistance. During water vapor exposure at 1200 °C, rare earth disilicates showed a good stability, which is contradictory with the literature, due to impurities—such as Si- and Al-hydroxides—in the water vapor jets. The presence of vertical cracks allowed the water vapor to reach the substrate and then to corrode it. It has been observed that thin vertical cracks induced some spallation after 24 h of corrosion.

  4. Thermal barrier coatings on gas turbine blades: Chemical vapor deposition (Review)

    Science.gov (United States)

    Igumenov, I. K.; Aksenov, A. N.

    2017-12-01

    Schemes are presented for experimental setups (reactors) developed at leading scientific centers connected with the development of technologies for the deposition of coatings using the CVD method: at the Technical University of Braunschweig (Germany), the French Aerospace Research Center, the Materials Research Institute (Tohoku University, Japan) and the National Laboratory Oak Ridge (USA). Conditions and modes for obtaining the coatings with high operational parameters are considered. It is established that the formed thermal barrier coatings do not fundamentally differ in their properties (columnar microstructure, thermocyclic resistance, thermal conductivity coefficient) from standard electron-beam condensates, but the highest growth rates and the perfection of the crystal structure are achieved in the case of plasma-chemical processes and in reactors with additional laser or induction heating of a workpiece. It is shown that CVD reactors can serve as a basis for the development of rational and more advanced technologies for coating gas turbine blades that are not inferior to standard electron-beam plants in terms of the quality of produced coatings and have a much simpler and cheaper structure. The possibility of developing a new technology based on CVD processes for the formation of thermal barrier coatings with high operational parameters is discussed, including a set of requirements for industrial reactors, high-performance sources of vapor precursors, and promising new materials.

  5. Thermal Cycling and High-Temperature Corrosion Tests of Rare Earth Silicate Environmental Barrier Coatings

    Science.gov (United States)

    Darthout, Émilien; Gitzhofer, François

    2017-09-01

    Lutetium and yttrium silicates, enriched with an additional secondary zirconia phase, environmental barrier coatings were synthesized by the solution precursor plasma spraying process on silicon carbide substrates. A custom-made oven was designed for thermal cycling and water vapor corrosion testing. The oven can test four specimens simultaneously and allows to evaluate environmental barrier performances under similar corrosion kinetics compared to turbine engines. Coatings structural evolution has been observed by SEM on the polished cross sections, and phase composition has been analyzed by XRD. All coatings have been thermally cycled between 1300 °C and the ambient temperature, without spallation, due to their porosity and the presence of additional secondary phase which increases the thermal cycling resistance. During water vapor exposure at 1200 °C, rare earth disilicates showed a good stability, which is contradictory with the literature, due to impurities—such as Si- and Al-hydroxides—in the water vapor jets. The presence of vertical cracks allowed the water vapor to reach the substrate and then to corrode it. It has been observed that thin vertical cracks induced some spallation after 24 h of corrosion.

  6. Life Prediction Issues in Thermal/Environmental Barrier Coatings in Ceramic Matrix Composites

    Science.gov (United States)

    Shah, Ashwin R.; Brewer, David N.; Murthy, Pappu L. N.

    2001-01-01

    Issues and design requirements for the environmental barrier coating (EBC)/thermal barrier coating (TBC) life that are general and those specific to the NASA Ultra-Efficient Engine Technology (UEET) development program have been described. The current state and trend of the research, methods in vogue related to the failure analysis, and long-term behavior and life prediction of EBCITBC systems are reported. Also, the perceived failure mechanisms, variables, and related uncertainties governing the EBCITBC system life are summarized. A combined heat transfer and structural analysis approach based on the oxidation kinetics using the Arrhenius theory is proposed to develop a life prediction model for the EBC/TBC systems. Stochastic process-based reliability approach that includes the physical variables such as gas pressure, temperature, velocity, moisture content, crack density, oxygen content, etc., is suggested. Benefits of the reliability-based approach are also discussed in the report.

  7. Failures of the thermal barriers of 900 MWe reactor coolant pumps

    Energy Technology Data Exchange (ETDEWEB)

    Peyrouty, P.

    1996-12-01

    This report describes the anomalies encountered in the thermal barriers of the reactor coolant pumps in French 900 MWe PWR power stations. In addition to this specific problem, it demonstrates how the fortuitous discovery of a fault during a sampling test enabled faults of a generic nature to be revealed in components which were not subject to periodic inspection, the failure of which could seriously affect safety. This example demonstrates the risk which can be associated with the deterioration in areas which are not examined periodically and for which there are no preceding signs which would make early detection of deterioration possible.

  8. Mixed Mode Fracture of Plasma Sprayed Thermal Barrier Coatings: Effects of Anisotropy and Heterogeneity

    Science.gov (United States)

    Zhu, Dongming; Choi, Sung R.; Ghosn, Louis L.

    2008-01-01

    The combined mode I-mode II fracture behavior of anisotropic ZrO2-8wt%Y2O3 thermal barrier coatings was determined in asymmetric flexure loading at both ambient and elevated temperatures. A fracture envelope of KI versus KII was determined for the coating material at ambient and elevated temperatures. Propagation angles of fracture as a function of KI/KII were also determined. The mixed-mode fracture behavior of the microsplat coating material was modeled using Finite Element approach to account for anisotropy and micro cracked structures, and predicted in terms of fracture envelope and propagation angle using mixed-mode fracture theories.

  9. Overview of the Westinghouse Small Modular Reactor building layout

    Energy Technology Data Exchange (ETDEWEB)

    Cronje, J. M. [Westinghouse Electric Company LLC, Centurion (South Africa); Van Wyk, J. J.; Memmott, M. J. [Westinghouse Electric Company LLC, Cranberry Township, PA (United States)

    2012-07-01

    The Westinghouse Small Modular Reactor (SMR) is an 800 MWt (>225 MWe) integral pressurized water reactor (iPWR), in which all of the components typically associated with the nuclear steam supply system (NSSS) of a nuclear power plant are incorporated within a single reactor pressure vessel. This paper is the third in a series of four papers, which describe the design and functionality of the Westinghouse SMR. It focuses in particular upon the plant building layout and modular design of the Westinghouse SMR. In the development of small modular reactors, the building layout is an area where the safety of the plant can be improved by applying new design approaches. This paper will present an overview of the Westinghouse SMR building layout and indicate how the design features improve the safety and robustness of the plant. The Westinghouse SMR is designed with no shared systems between individual reactor units. The main buildings inside the security fence are the nuclear island, the rad-waste building, the annex building, and the turbine building. All safety related equipment is located in the nuclear island, which is a seismic class 1 building. To further enhance the safety and robustness of the design, the reactor, containment, and most of the safety related equipment are located below grade on the nuclear island. This reduces the possibility of severe damage from external threats or natural disasters. Two safety related ultimate heat sink (UHS) water tanks that are used for decay heat removal are located above grade, but are redundant and physically separated as far as possible for improved safety. The reactor and containment vessel are located below grade in the center of the nuclear island. The rad-waste and other radioactive systems are located on the bottom floors to limit the radiation exposure to personnel. The Westinghouse SMR safety trains are completely separated into four unconnected quadrants of the building, with access between quadrants only allowed

  10. Linear laser fast scanning thermography NDT for artificial disbond defects in thermal barrier coatings.

    Science.gov (United States)

    Liu, Zhanwei; Jiao, Dacheng; Shi, Wenxiong; Xie, Huimin

    2017-12-11

    Interface disbond in thermal barrier coatings (TBCs) is one of the key issues that cause their premature failure. In general, blind hole defects are often used as substitutes in transient thermography. The linear laser fast scanning thermography (LLFST) method was developed in this study and combined with several post-processing algorithms to accurately detect blind hole defects in TBCs. Through numerical simulation and experimental verification, a unique thermal response characteristic of blind holes in the cooling phase, namely a distinct "tailing" phenomenon, was summarized and utilized to recognize small defects. Validation tests indicated that blind holes with diameters of 1, 2, and 3 mm and artificial disbonds with diameters of 2 and 3 mm in TBCs are detected with high efficiency.

  11. Luminescence-Based Diagnostics of Thermal Barrier Coating Health and Performance

    Science.gov (United States)

    Eldridge, Jeffrey I.

    2013-01-01

    Thermal barrier coatings (TBCs) are typically composed of translucent ceramic oxides that provide thermal protection for metallic components exposed to high-temperature environments in both air- and land-based turbine engines. For advanced turbine engines designed for higher temperature operation, a diagnostic capability for the health and performance of TBCs will be essential to indicate when a mitigating action needs to be taken before premature TBC failure threatens engine performance or safety. In particular, it is shown that rare-earth-doped luminescent sublayers can be integrated into the TBC structure to produce luminescence emission that can be monitored to assess TBC erosion and delamination progression, and to map surface and subsurface temperatures as a measure of TBC performance. The design and implementation of these TBCs with integrated luminescent sublayers are presented.

  12. Study on Stress Development in the Phase Transition Layer of Thermal Barrier Coatings

    Directory of Open Access Journals (Sweden)

    Yijun Chai

    2016-09-01

    Full Text Available Stress development is one of the significant factors leading to the failure of thermal barrier coating (TBC systems. In this work, stress development in the two phase mixed zone named phase transition layer (PTL, which grows between the thermally grown oxide (TGO and the bond coat (BC, is investigated by using two different homogenization models. A constitutive equation of the PTL based on the Reuss model is proposed to study the stresses in the PTL. The stresses computed with the proposed constitutive equation are compared with those obtained with Voigt model-based equation in detail. The stresses based on the Voigt model are slightly higher than those based on the Reuss model. Finally, a further study is carried out to explore the influence of phase transition proportions on the stress difference caused by homogenization models. Results show that the stress difference becomes more evident with the increase of the PTL thickness ratio in the TGO.

  13. FAILURE MECHANISMS OF THERMAL BARRIER COATINGS INTERNAL COMBUSTION ENGINES AND llMPROVEMENTS

    Directory of Open Access Journals (Sweden)

    ADNAN PARLAK

    2003-04-01

    Full Text Available MechanicaJ properties of high performance ceramics have been improved to the point where their use in heat engines is possible. The high temperature strength and low thermal expansion properties of bigh performance ceramics offer an advantage over metals in the development of non-water cooling engine. However, because bard environment in diesel engine combustion chamber, solving the problem of durabiUty of TBC is important. DurabiUty of thermal barrier coatings(TBC is liınited by two main failure mechanisms: Therınal expansion nlİsmatch betwcen bond coat and top coat and bond coat oxidation. Both of these can cause failure of the ceramic top coat. Developments of recent years sholv that bond coats \\Vith higher oxidation resistance tend to have better coating system cyclic lives

  14. Some recent trends in research and technology of advanced thermal barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, U.; Leyens, Ch.; Fritscher, K.; Peters, M.; Saruhan-Brings, B. [Deutsches Zentrum fur Luft- und Raumfahrt, DLR, Institute of Mateirals Research, Koln (Germany); Lavigne, O.; Dorvaux, J.M.; Poulain, M.; Mevrel, R.; Caliez, M. [Office National d' Etudes et de Recherches Aerospatiales (ONERA), Dept. of Metallic Materials and Processing, 92 - Chatillon (France)

    2003-01-01

    Ceramic thermal barrier coatings (TBCs) offer the potential to significantly improve efficiencies of aero engines as well as stationary gas turbines for power generation. On internally cooled turbine parts temperature gradients of the order of 100 to 150 deg. C can be achieved. Today, state-of-the-art TBCs, typically consisting of an yttria-stabilised zirconia top coat and a metallic bond coat deposited onto a superalloy substrate, are mainly used to extend lifetime. Further efficiency improvements require TBCs being an integral part of the component which, in turn, requires reliable and predictable TBC performance. Presently, TBCs produced by electron beam physical vapour deposition are favoured for high performance applications. The paper highlights critical R and D needs for advanced TBC systems with a special focus on reduced thermal conductivity and life prediction needs. (authors)

  15. Effects of Thermal Barrier Coatings on Approaches to Turbine Blade Cooling

    Science.gov (United States)

    Boyle, Robert J.

    2007-01-01

    Reliance on Thermal Barrier Coatings (TBC) to reduce the amount of air used for turbine vane cooling is beneficial both from the standpoint of reduced NOx production, and as a means of improving cycle efficiency through improved component efficiency. It is shown that reducing vane cooling from 10 to 5 percent of mainstream air can lead to NOx reductions of nearly 25 percent while maintaining the same rotor inlet temperature. An analysis is given which shows that, when a TBC is relied upon in the vane thermal design process, significantly less coolant is required using internal cooling alone compared to film cooling. This is especially true for small turbines where internal cooling without film cooling permits the surface boundary layer to remain laminar over a significant fraction of the vane surface.

  16. High-temperature Fabry-Perot-based strain sensor for ceramic barrier filters

    Science.gov (United States)

    Weinstein, Shmuel J.; Vuppala, Veerendra B.; Gunther, Michael F.; Wang, Anbo; Murphy, Kent A.; Claus, Richard O.

    1994-02-01

    We report results from a program to develop fiber-optic sensor-based instrumentation methods to allow the in-situ analysis of ceramic barrier filters. The sensor used was an extrinsic Fabry-Perot cavity created between the ends of two longitudinally aligned fibers. Filters instrumented with these fiber sensors were tested in a combustor simulator at the Westinghouse Science and Technology Center. These tests were performed using silica optical fibers capable of withstanding the high temperature and harsh chemical environment of the combustor. The single-ended approach of the reflective Fabry-Perot sensors is well suited for high thermal strain measurements. The results from several tests are presented.

  17. Temperature Mapping of Air Film-Cooled Thermal Barrier Coated Surfaces Using Phosphor Thermometry

    Science.gov (United States)

    Eldridge, Jeffrey I.

    2016-01-01

    While the effects of thermal barrier coating (TBC) thermal protection and air film cooling effectiveness for jet engine components are usually studied separately, their contributions to combined cooling effectiveness are interdependent and are not simply additive. Therefore, combined cooling effectiveness must be measured to achieve an optimum balance between TBC thermal protection and air film cooling. Phosphor thermometry offers several advantages for mapping temperatures of air film cooled surfaces. While infrared thermography has been typically applied to study air film cooling effectiveness, temperature accuracy depends on knowing surface emissivity (which may change) and correcting for effects of reflected radiation. Because decay time-based full-field phosphor thermometry is relatively immune to these effects, it can be applied advantageously to temperature mapping of air film-cooled TBC-coated surfaces. In this presentation, an overview will be given of efforts at NASA Glenn Research Center to perform temperature mapping of air film-cooled TBC-coated surfaces in a burner rig test environment. The effects of thermal background radiation and flame chemiluminescence on the measurements are investigated, and the strengths and limitations of this method for studying air film cooling effectiveness are discussed.

  18. Splenectomy attenuates severe thermal trauma-induced intestinal barrier breakdown in rats.

    Science.gov (United States)

    Liu, Xiang-dong; Chen, Zhen-yong; Yang, Peng; Huang, Wen-guang; Jiang, Chun-fang

    2015-12-01

    The severe local thermal trauma activates a number of systemic inflammatory mediators, such as TNF-α, NF-κB, resulting in a disruption of gut barrier. The gastrointestinal tight junction (TJ) is highly regulated by membrane-associated proteins including zonula occludens protein-1 (ZO-1) and occludin, which can be modulated by inflammatory cytokines. As splenectomy has been shown to reduce secretion of cytokines, we hypothesized that (1) severe scald injury up-regulates TNF-α and NF-κB, meanwhile down-regulates expression of ZO-1 and occludin, leading to the increased intestinal permeability, and (2) splenectomy can prevent the burn-induced decrease in ZO-1 and occludin expression, resulting in improved intestinal barrier. Wistar rats undergoing a 30% total body surface area (TBSA) thermal trauma were randomized to receive an accessorial splenectomy meanwhile or not. Intestinal injury was assessed by histological morphological analysis, and serum endotoxin levels, TNF-α, NF-κB, ZO-1 and occludin levels were detected by Western blotting in the terminal ileum mucosal tissue. 30% TBSA burn caused a significant increase in serum endotoxin levels, but NF-κB, and TNF-α, and the average intestinal villus height and mucosal thickness were decreased significantly. Burn injury could also markedly decrease the levels of ZO-1 and occludin in terminal ileum mucosal tissue (all PSplenectomy at 7th day after burn significantly reversed the burn-induced breakdown of ZO-1 and occludin (all PSplenectomy may provide a therapeutic benefit in restoring burn-induced intestinal barrier by decreasing the release of inflammatory cytokines and recovering TJ proteins.

  19. Thermal stability of amorphous tungsten/tungsten nitride synthesis using HFCVD as a diffusion barrier for copper

    Energy Technology Data Exchange (ETDEWEB)

    Asgary, Somayeh; Hantehzadeh, Mohammad Reza; Ghoranneviss, Mahmood [Islamic Azad University, Plasma Physics Research Center, Science and Research Branch, Tehran (Iran, Islamic Republic of); Boochani, Arash [Islamic Azad University, Department of Physics, Kermanshah Branch, Kermanshah (Iran, Islamic Republic of)

    2016-05-15

    The amorphous W/WN bi-layer with excellent thermal stability was successfully prepared by hot-filament chemical vapor deposition method on SiO{sub 2}/Si substrate. It was found that the W/WN bi-layer is technological importance because of its low resistivity and good diffusion barrier properties between Cu and Si up to 700 C for 30 min. The thermal stability was evaluated by X-ray diffractometer (XRD) and scanning electron microscope. The XRD results show that the Cu{sub 3}Si phase was formed by Cu diffusion through W/WN barrier for the 800 C annealed sample. The formation of the Cu-Si compounds denotes the failure of the W/WN diffusion barrier with rapid increase in sheet resistance of the film. The microstructure of the interface between W/WN and Cu reflects the stability and breakdown of the barriers. The failure of this amorphous barrier occurs with heat treatment when the deposited amorphous barrier material crystallizes. The major part of Cu diffusion in polycrystalline structure with disordered grain boundaries is controlled by grain boundaries. AFM results indicated a rapid increase in surface roughness at the diffusion barrier failure temperature. It was found that the grain size plays an important factor to control the thermally stability of the W/WN bi-layer. (orig.)

  20. Current status of Westinghouse tubular solid oxide fuel cell program

    Energy Technology Data Exchange (ETDEWEB)

    Parker, W.G. [Westinghouse Science and Technology Center, Pittsburgh, PA (United States)

    1996-04-01

    In the last ten years the solid oxide fuel cell (SOFC) development program at Westinghouse has evolved from a focus on basic material science to the engineering of fully integrated electric power systems. Our endurance for this cell is 5 to 10 years. To date we have successfully operated at power for over six years. For power plants it is our goal to have operated before the end of this decade a MW class power plant. Progress toward these goals is described.

  1. Validation and Benchmarking of Westinghouse BWR lattice physics methods

    OpenAIRE

    Luszczek, Karol

    2015-01-01

    A lattice physics code is a vital tool, forming a base of reactor coreanalysis. It enables the neutronic properties of the fuel assembly to becalculated and generates a proper set of data to be used by a 3-D full coresimulator. Due to advancement and complexity of modern Boiling WaterReactor assembly designs, a new deterministic lattice physics codeis being developed at Westinghouse Sweden AB, namely PHOENIX5.Each time a new code is written, its methodology of solving the neutrontransport equ...

  2. NDE of degradation of thermal barrier coating by means of impedance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Kazuhiro; Minkov, Dorian; Shoji, Tetsuo [Tohoku Univ., Research Inst. for Fracture Technology, Sendai (Japan); Sato, Minoru; Hashimoto, Hideo [Tohoku Electric Power Co. Inc., Sendai (Japan)

    1999-04-01

    Nondestructive evaluation of thermal barrier coating (TBC) degradation during service operation has received a wide attention for service life prediction of advanced gas turbines. In this work, TBC on nickel base superalloy degraded at various degrees by thermal aging is investigated. Particularly, TBC and Metal-Chromium-Aluminum-Yttrium alloy (MCrAlY) (M indicates iron (Fe), cobalt (Co), nickel (Ni) or these combinations) bond coating interface where a detrimental reaction takes place and forms various reaction products during thermal aging, is studied in detail. Formation kinetics and physical properties of the reaction layer are evaluated by means of Impedance Spectroscopy (IS). Specimens aged at higher temperature and a longer aging time shows larger impedance. The impedance behavior of TBC and bond coating is found to be markedly changed by the formation of the reaction layer. Physical properties and thickness of the reaction layer are evaluated using the change of the impedance. A mechanistic interpretation of the cause of change in the physical properties and IS behavior are described. (Author)

  3. Development of YSZ Thermal Barrier Coatings Using Axial Suspension Plasma Spraying

    Directory of Open Access Journals (Sweden)

    Dapeng Zhou

    2017-08-01

    Full Text Available The axial injection of the suspension in the atmospheric plasma spraying process (here called axial suspension plasma spraying is an attractive and advanced thermal spraying technology especially for the deposition of thermal barrier coatings (TBCs. It enables the growth of columnar-like structures and, hence, combines advantages of electron beam-physical vapor deposition (EB-PVD technology with the considerably cheaper atmospheric plasma spraying (APS. In the first part of this study, the effects of spraying conditions on the microstructure of yttria partially-stabilized zirconia (YSZ top coats and the deposition efficiency were investigated. YSZ coatings deposited on as-sprayed bond coats with 5 wt % solid content suspension appeared to have nicely-developed columnar structures. Based on the preliminary results, the nicely developed columnar coatings with variations of the stand-off distances and yttria content were subjected to thermal cycling tests in a gas burner rig. In these tests, all columnar structured TBCs showed relatively short lifetimes compared with porous APS coatings. Indentation measurements for Young’s modulus and fracture toughness on the columns of the SPS coatings indicated a correlation between mechanical properties and lifetime for the SPS samples. A simplified model is presented which correlates mechanical properties and lifetime of SPS coatings.

  4. Thermal barrier coatings issues in advanced land-based gas turbines

    Science.gov (United States)

    Parks, William P.; Hoffman, Eugene E.; Lee, Woo Y.; Wright, Ian G.

    1995-01-01

    The Department of Energy's Advanced Turbine Systems (ATS) program is aimed at fostering the development of a new generation of land-based gas turbine systems with overall efficiencies significantly beyond those of current state-of-the-art machines, as well as greatly increased times between inspection and refurbishment, improved environmental impact, and decreased cost. The proposed duty cycle of ATS machines will emphasize different criteria in the selection of materials for the critical components. In particular, thermal barrier coatings (TBC's) will be an essential feature of the hot gas path components in these machines. In fact, the goals of the ATS will require significant improvements in TBC technology, since these turbines will be totally reliant on TBC's, which will be required to function on critical components such as the first stage vanes and blades for times considerably in excess of those experienced in current applications. Issues that assume increased importance are the mechanical and chemical stability of the ceramic layer and of the metallic bond coat; the thermal expansion characteristics and compliance of the ceramic layer; and the thermal conductivity across the thickness of the ceramic layer. Obviously, the ATS program provides a very challenging opportunity for TBC's, and involves some significant opportunities to extend this technology. A significant TBC development effort is planned in the ATS program which will address these key issues.

  5. Assessment of ISLOCA risk: Methodology and application to a Westinghouse four-loop ice condenser plant

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, D.L.; Auflick, J.L.; Haney, L.N. [EG and G Idaho, Inc., Idaho Falls, ID (United States)

    1992-04-01

    Inter-system loss-of-coolant accidents (ISLOCAs) have been identified as important contributors to offsite risk for some nuclear power plants. A methodology has been developed for identifying and evaluating plant-specific hardware designs, human factors issues, and accident consequence factors relevant to the estimation of ISLOCA core damage frequency and risk. This report presents a detailed description of the application of this analysis methodology to a Westinghouse four-loop ice condenser plant. This document also includes appendices A through I which provide: System descriptions; ISLOCA event trees; human reliability analysis; thermal hydraulic analysis; core uncovery timing calculations; calculation of system rupture probability; ISLOCA consequences analysis; uncertainty analysis; and component failure analysis.

  6. Utility of Photochemical Traits as Diagnostics of Thermal Tolerance amongst Great Barrier Reef Corals

    Directory of Open Access Journals (Sweden)

    Matthew R. Nitschke

    2018-02-01

    Full Text Available Light availability is considered a key factor regulating the thermal sensitivity of reef building corals, where excessive excitation of photosystem II (PSII further exacerbates pressure on photochemical pathways already compromised by heat stress. Coral symbionts acclimate to changes in light availability (photoacclimation by continually fine-tuning the photochemical operating efficiency of PSII. However, how this process adjusts throughout the warmest months in naturally heat-tolerant or sensitive species is unknown, and whether this influences the capacity to tolerate transient heat stress is untested. We therefore examined the PSII photophysiology of 10 coral species (with known thermal tolerances from shallow reef environments at Heron Island (Great Barrier Reef, Australia, in spring (October-November, 2015 vs. summer (February-March, 2016. Corals were maintained in flow-through aquaria and rapid light curve (RLC protocols using pulse amplitude modulated (PAM fluorometry captured changes in the PSII photoacclimation strategy, characterized as the minimum saturating irradiance (Ek, and the extent of photochemical ([1 – C], operating efficiency vs. non-photochemical ([1 – Q] energy dissipation. Values of Ek across species were >2-fold higher in all coral species in spring, consistent with a climate of higher overall light exposure (i.e., higher PAR from lower cloud cover, rainfall and wind speed compared with summer. Summer decreases in Ek were combined with a shift toward preferential photochemical quenching in all species. All coral species were subsequently subjected to thermal stress assays. An equivalent temperature-ramping profile of 1°C increase per day and then maintenance at 32°C was applied in each season. Despite the significant seasonal photoacclimation, the species hierarchy of thermal tolerance [maximum quantum yields of PSII (Fv/Fm, monitored at dawn and dusk] did not shift between seasons, except for Pocillopora

  7. Mesoscopic Nonlinear Elastic Modulus of Thermal Barrier Coatings Determined by Cylindrical Punch Indentation

    Science.gov (United States)

    Eldridge, Jeffrey I.; Zhu, Dong-Ming; Miller, Robert A.

    2000-01-01

    Cylindrical punch indentations are performed to determine the effective modulus of a plasma-sprayed ZrO2-8Wt%Y2O3 thermal barrier coating (TBC) as a function of coating depth. Cylindrical punch indentations offer significant advantages over pointed (Vickers, Berkovich, or Knoop) indentations for materials that do not exhibit linear elastic behavior. Cyclic loading with a cylindrical punch clearly shows the TBCs to exhibit nonlinear elastic behavior with significant hysteresis that is related to the compaction and internal sliding within the plasma-spray splat microstructure. In addition, the effect of a high heat flux laser treatment was shown to produce a gradient both in the effective TBC modulus and degree of loading/unloading hysteresis with depth.

  8. Deposition stress effects on the life of thermal barrier coatings on burner rigs

    Science.gov (United States)

    Watson, J. W.; Levine, S. R.

    1984-01-01

    A study of the effect of plasma spray processing parameters on the life of a two layer thermal barrier coating was conducted. The ceramic layer was plasma sprayed at plasma arc currents of 900 and 600 amps onto uncooled tubes, cooled tubes, and solid bars of Waspalloy in a lathe with 1 or 8 passes of the plasma gun. These processing changes affected the residual stress state of the coating. When the specimens were tested in a Mach 0.3 cyclic burner rig at 1130 deg C, a wide range of coating lives resulted. Processing factors which reduced the residual stress state in the coating, such as reduced plasma temperature and increased heat dissipation, significantly increased coating life.

  9. High Temperature Damping Behavior of Plasma-Sprayed Thermal Barrier and Protective Coatings

    Science.gov (United States)

    Zhu, Dongming; Miller, Robert A.; Duffy, Kirsten P.; Ghosn, Louis J.

    2010-01-01

    A high temperature damping test apparatus has been developed using a high heat flux CO 2 laser rig in conjunction with a TIRA S540 25 kHz Shaker and Polytec OFV 5000 Vibrometer system. The test rig has been successfully used to determine the damping performance of metallic and ceramic protective coating systems at high temperature for turbine engine applications. The initial work has been primarily focused on the microstructure and processing effects on the coating temperature-dependence damping behavior. Advanced ceramic coatings, including multicomponent tetragonal and cubic phase thermal barrier coatings, along with composite bond coats, have also been investigated. The coating high temperature damping mechanisms will also be discussed.

  10. Constrained sintering of an air-plasma-sprayed thermal barrier coating

    Energy Technology Data Exchange (ETDEWEB)

    Cocks, A.C.F., E-mail: alan.cocks@eng.ox.ac.uk [Department of Engineering Science, Parks Rd., Oxford OX1 3PJ (United Kingdom); Fleck, N.A. [Cambridge University Engineering Department, Trumpington St., Cambridge CB2 1PZ (United Kingdom)

    2010-07-15

    A micromechanical model is presented for the constrained sintering of an air-plasma-sprayed, thermal barrier coating upon a thick superalloy substrate. The coating comprises random splats with intervening penny-shaped cracks. The crack faces make contact at asperities, which progressively sinter in-service by interfacial diffusion, accommodated by bulk creep. Diffusion is driven by the reduction in interfacial energy at the developing contacts and by the local asperity contact stress. At elevated operating temperature, both sintering and creep strains accumulate within the plane of the coating. The sensitivities of sintering rate and microstructure evolution rate to the kinetic parameters and thermodynamic driving forces are explored. It is demonstrated that the sintering response is governed by three independent timescales, as dictated by the material and geometric properties of the coating. Finally, the role of substrate constraint is assessed by comparing the rate of constrained sintering with that for free sintering.

  11. Use of indentation technique to measure elastic modulus of plasma-sprayed zirconia thermal barrier coating

    Energy Technology Data Exchange (ETDEWEB)

    Singh, J.P.; Sutaria, M. [Argonne National Lab., IL (United States). Energy Technology Div.; Ferber, M. [Oak Ridge National Lab., TN (United States)

    1997-01-01

    Elastic modulus of an yttria partially stabilized zirconia (YSZ) thermal barrier coating (TBC) was evaluated with a Knoop indentation technique. The measured elastic modulus values for the coating ranged from 68.4 {+-} 22.6 GPa at an indentation load of 50 g to 35.7 {+-} 9.8 at an indentation load of 300 g. At higher loads, the elastic modulus values did not change significantly. This steady-state value of 35.7 GPa for ZrO{sub 2} TBC agreed well with literature values obtained by the Hertzian indentation method. Furthermore, the measured elastic modulus for the TBC is lower than that reported for bulk ZrO{sub 2} ({approx} 190 GPa). This difference is believed to be due to the presence of a significant amount of porosity and microcracks in the TBCs. Hardness was also measured.

  12. Morphology, thermal, mechanical, and barrier properties of graphene oxide/poly(lactic acid) nanocomposite films

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong Woo; Choi, Hyun Muk [Kyonggi University, Suwon (Korea, Republic of)

    2016-01-15

    To improve the physical and gas barrier properties of biodegradable poly(lactic acid) (PLA) film, two graphene nanosheets of highly functionalized graphene oxide (0.3 wt% to 0.7 wt%) and low-functionalized graphene oxide (0.5 wt%) were incorporated into PLA resin via solution blending method. Subsequently, we investigated the effects of material parameters such as loading level and degree of functionalization for the graphene nanosheets on the morphology and properties of the resultant nanocomposites. The highly functionalized graphene oxide (GO) caused more exfoliation and homogeneous dispersion in PLA matrix as well as more sustainable suspensions in THF, compared to low-functionalized graphene oxide (LFGO). When loaded with GO from 0.3 wt% to 0.7 wt%, the glass transition temperature, degree of crystallinity, tensile strength and modulus increased steadily. The GO gave rise to more pronounced effect in the thermal and mechanical reinforcement, relative to LFGO. In addition, the preparation of fairly transparent PLA-based nanocomposite film with noticeably improved barrier performance achieved only when incorporated with GO up to 0.7wt%. As a result, GO may be more compatible with hydrophilic PLA resin, compared to LFGO, resulting in more prominent enhancement of nanocomposites properties.

  13. Saturated Resin Ectopic Regeneration by Non-Thermal Dielectric Barrier Discharge Plasma

    Directory of Open Access Journals (Sweden)

    Chunjing Hao

    2017-11-01

    Full Text Available Textile dyes are some of the most refractory organic compounds in the environment due to their complex and various structure. An integrated resin adsorption/Dielectric Barrier Discharge (DBD plasma regeneration was proposed to treat the indigo carmine solution. It is the first time to report ectopic regeneration of the saturated resins by non-thermal Dielectric Barrier Discharge. The adsorption/desorption efficiency, surface functional groups, structural properties, regeneration efficiency, and the intermediate products between gas and liquid phase before and after treatment were investigated. The results showed that DBD plasma could maintain the efficient adsorption performance of resins while degrading the indigo carmine adsorbed by resins. The degradation rate of indigo carmine reached 88% and the regeneration efficiency (RE can be maintained above 85% after multi-successive regeneration cycles. The indigo carmine contaminants were decomposed by a variety of reactive radicals leading to fracture of exocyclic C=C bond, which could cause decoloration of dye solution. Based on above results, a possible degradation pathway for the indigo carmine by resin adsorption/DBD plasma treatment was proposed.

  14. Review of hot corrosion of thermal barrier coatings of gas turbine

    Directory of Open Access Journals (Sweden)

    LIU Yongbao

    2017-03-01

    Full Text Available The review was done in order to make clear the problem of the hot corrosion of the Thermal Barrier Coatings(TBCsduring gas turbine serving. This paper summarizes the factors resulting from the hot corrosion of TBCs during turbine service and classifies methods for enhancing the corrosive resistance of TBCs. A prospective methodology for improving corrosion resistance is also formulated. The main types of corrosion coating include phase reaction, oxidizing of the bond coating, salt-fog corrosion, CMAS corrosion and fuel impurity corrosion. So far, methods for improving the corrosion resistance of TBCs include developing new coating materials, anticorrosive treatment on the surface of TBCs, modifying the stacking configuration and improving the cleansing functions of the gas turbines. In the future, developing new materials with excellent performance will still be the main direction for boosting the improvement of the hot corrosion resistance of TBCs. Simultaneously, improving the tacking configuration and nanotechnology of TBC coatings are potential approaches for improving corrosion resistance. With the development of a Ceramic Matrix Composite (CMC, the focus of the hot corrosion of TBCs may turn to that of Environmental Barrier Coatings (EBCs.

  15. Advanced thermal barrier coatings for operation in high hydrogen content fueled gas turbines.

    Energy Technology Data Exchange (ETDEWEB)

    Sampath, Sanjay [Stony Brook Univ., NY (United States)

    2015-04-02

    The Center for Thermal Spray Research (CTSR) at Stony Brook University in partnership with its industrial Consortium for Thermal Spray Technology is investigating science and technology related to advanced metallic alloy bond coats and ceramic thermal barrier coatings for applications in the hot section of gasified coal-based high hydrogen turbine power systems. In conjunction with our OEM partners (GE and Siemens) and through strategic partnership with Oak Ridge National Laboratory (ORNL) (materials degradation group and high temperature materials laboratory), a systems approach, considering all components of the TBC (multilayer ceramic top coat, metallic bond coat & superalloy substrate) is being taken during multi-layered coating design, process development and subsequent environmental testing. Recent advances in process science and advanced in situ thermal spray coating property measurement enabled within CTSR has been incorporated for full-field enhancement of coating and process reliability. The development of bond coat processing during this program explored various aspects of processing and microstructure and linked them to performance. The determination of the bond coat material was carried out during the initial stages of the program. Based on tests conducted both at Stony Brook University as well as those carried out at ORNL it was determined that the NiCoCrAlYHfSi (Amdry) bond coats had considerable benefits over NiCoCrAlY bond coats. Since the studies were also conducted at different cycling frequencies, thereby addressing an associated need for performance under different loading conditions, the Amdry bond coat was selected as the material of choice going forward in the program. With initial investigations focused on the fabrication of HVOF bond coats and the performance of TBC under furnace cycle tests , several processing strategies were developed. Two-layered HVOF bond coats were developed to render optimal balance of density and surface roughness

  16. Liquid Feedstock Plasma Spraying: An Emerging Process for Advanced Thermal Barrier Coatings

    Science.gov (United States)

    Markocsan, Nicolaie; Gupta, Mohit; Joshi, Shrikant; Nylén, Per; Li, Xin-Hai; Wigren, Jan

    2017-08-01

    Liquid feedstock plasma spraying (LFPS) involves deposition of ultrafine droplets of suspensions or solution precursors (typically ranging from nano- to submicron size) and permits production of coatings with unique microstructures that are promising for advanced thermal barrier coating (TBC) applications. This paper reviews the recent progress arising from efforts devoted to development of high-performance TBCs using the LFPS approach. Advancements in both suspension plasma spraying and solution precursor plasma spraying, which constitute the two main variants of LFPS, are presented. Results illustrating the different types of the microstructures that can be realized in LFPS through appropriate process parameter control, model-assisted assessment of influence of coating defects on thermo-mechanical properties and the complex interplay between pore coarsening, sintering and crystallite growth in governing thermal conductivity are summarized. The enhancement in functional performances/lifetime possible in LFPS TBCs with multilayered architectures and by incorporating new pyrochlore chemistries such as gadolinium zirconate, besides the conventional single 8 wt.% yttria-stabilized zirconia insulating ceramic layer, is specifically highlighted.

  17. Influence of Bondcoat Spray Process on Lifetime of Suspension Plasma-Sprayed Thermal Barrier Coatings

    Science.gov (United States)

    Gupta, M.; Markocsan, N.; Li, X.-H.; Östergren, L.

    2018-01-01

    Development of thermal barrier coatings (TBCs) manufactured by suspension plasma spraying (SPS) is of high commercial interest as SPS has been shown capable of producing highly porous columnar microstructures similar to the conventionally used electron beam-physical vapor deposition. However, lifetime of SPS coatings needs to be improved further to be used in commercial applications. The bondcoat microstructure as well as topcoat-bondcoat interface topography affects the TBC lifetime significantly. The objective of this work was to investigate the influence of different bondcoat deposition processes for SPS topcoats. In this work, a NiCoCrAlY bondcoat deposited by high velocity air fuel (HVAF) was compared to commercial vacuum plasma-sprayed NiCoCrAlY and PtAl diffusion bondcoats. All bondcoat variations were prepared with and without grit blasting the bondcoat surface. SPS was used to deposit the topcoats on all samples using the same spray parameters. Lifetime of these samples was examined by thermal cyclic fatigue testing. Isothermal heat treatment was performed to study bondcoat oxidation over time. The effect of bondcoat deposition process and interface topography on lifetime in each case has been discussed. The results show that HVAF could be a suitable process for bondcoat deposition in SPS TBCs.

  18. Depth-Penetrating Temperature Measurements of Thermal Barrier Coatings Incorporating Thermographic Phosphors

    Science.gov (United States)

    Eldridge, Jeffrey I.; Bencic, Timothy J..; Allison, Stephen W.; Beshears, David L.

    2003-01-01

    Thermographic phosphors have been previously demonstrated to provide effective non-contact, emissivity-independent surface temperature measurements. Because of the translucent nature of thermal barrier coatings (TBCs), thermographic phosphor-based temperature measurements can be extended beyond the surface to provide depth-selective temperature measurements by incorporating the thermographic phosphor layer at the depth where the temperature measurement is desired. In this paper, thermographic phosphor (Y2O3:Eu) fluorescence decay time measurements are demonstrated to provide through-the-coating thickness temperature readings up to 1100 C with the phosphor layer residing beneath a 100 micron thick TBC (plasma-sprayed 8wt% yttria-stabilized zirconia). With an appropriately chosen excitation wavelength and detection configuration, it is shown that sufficient phosphor emission is generated to provide effective temperature measurements, despite the attenuation of both the excitation and emission intensities by the overlying TBC. This depth-penetrating temperature measurement capability should prove particularly useful for TBC diagnostics where a large thermal gradient is typically present across the TBC thickness. The fluorescence decay from the Y2O3:Eu layer exhibited both an initial short-term exponential rise and a longer-term exponential decay. The rise time constant was demonstrated to provide better temperature indication below 500 C while the decay time constant was a better indicator at higher temperatures.

  19. A Robot Trajectory Optimization Approach for Thermal Barrier Coatings Used for Free-Form Components

    Science.gov (United States)

    Cai, Zhenhua; Qi, Beichun; Tao, Chongyuan; Luo, Jie; Chen, Yuepeng; Xie, Changjun

    2017-10-01

    This paper is concerned with a robot trajectory optimization approach for thermal barrier coatings. As the requirements of high reproducibility of complex workpieces increase, an optimal thermal spraying trajectory should not only guarantee an accurate control of spray parameters defined by users (e.g., scanning speed, spray distance, scanning step, etc.) to achieve coating thickness homogeneity but also help to homogenize the heat transfer distribution on the coating surface. A mesh-based trajectory generation approach is introduced in this work to generate path curves on a free-form component. Then, two types of meander trajectories are generated by performing a different connection method. Additionally, this paper presents a research approach for introducing the heat transfer analysis into the trajectory planning process. Combining heat transfer analysis with trajectory planning overcomes the defects of traditional trajectory planning methods (e.g., local over-heating), which helps form the uniform temperature field by optimizing the time sequence of path curves. The influence of two different robot trajectories on the process of heat transfer is estimated by coupled FEM models which demonstrates the effectiveness of the presented optimization approach.

  20. Temperature measurement involving nanostructured thermal barrier coating using a multiwavelength pyrometer

    Science.gov (United States)

    Ng, Daniel

    1996-01-01

    It has been reported that erroneous results were obtained when a conventional pyrometer was used to measure the surface temperature of turbine engine components. Temperatures discrepancies were observed in components which were identical, except that one had its measured surface covered by a nanostructured thermal barrier coating (TBC) whereas the other component's surface was not so coated. These components were placed in an identical environment, receiving identical heat fluxes. A pyrometer measured the TBC covered surface hundreds degrees lower. These coatings were about 25 (mu)m thick, consisting of hundreds of layers of finer structures. The TBC's had very low thermal conductivity, heat flux calculations indicated that the temperatures of the coated surface should exhibit much higher temperature than the uncoated surface. Because these coatings were transparent to radiation from the visible to the infrared region, the temperatures measured by the pyrometer should be the temperature of the covered surface. Turbo components' performance and service life depend critically on the temperatures that it would experience; it is therefore important to know accurately and confidently the real surface temperature. Out of these concerns, an investigation into the measurement of nanostructured material surface temperature was carried out.

  1. Overview on Recent Developments of Bondcoats for Plasma-Sprayed Thermal Barrier Coatings

    Science.gov (United States)

    Naumenko, D.; Pillai, R.; Chyrkin, A.; Quadakkers, W. J.

    2017-12-01

    The performance of MCrAlY (M = Ni, Co) bondcoats for atmospheric plasma-sprayed thermal barrier coatings (APS-TBCs) is substantially affected by the contents of Co, Ni, Cr, and Al as well as minor additions of Y, Hf, Zr, etc., but also by manufacturing-related properties such as coating thickness, porosity, surface roughness, and oxygen content. The latter properties depend in turn on the exact technology and set of parameters used for bondcoat deposition. The well-established LPPS process competes nowadays with alternative technologies such as HVOF and APS. In addition, new technologies have been developed for bondcoats manufacturing such as high-velocity APS or a combination of HVOF and APS for application of a flashcoat. Future developments of the bondcoat systems will likely include optimization of thermal spraying methods for obtaining complex bondcoat roughness profiles required for extended APS-TBC lifetimes. Introduction of the newest generation single-crystal superalloys possessing low Cr and high Al and refractory metals (Re, Ru) contents will require definition of new bondcoat compositions and/or multilayered bondcoats to minimize interdiffusion issues. The developments of new bondcoat compositions may be substantially facilitated using thermodynamic-kinetic modeling, the vast potential of which has been demonstrated in recent years.

  2. Numerical investigation of damage protective oxide mechanisms in thermal barrier system for aeronautical turbine blade.

    Directory of Open Access Journals (Sweden)

    khelifa hocine

    2015-03-01

    Full Text Available The choice of a material for a given application requires insuring a good durability in its conditions of employment, in particular environmental. It is especially true for the systems destined to work in corrosive hot atmospheres. For it, the knowledge and the understanding of the corrosion phenomena, oxidization, ageing and damage are indispensable in order to anticipate the life period of the structures and to propose the adapted protective solutions. The study of the corrosion in high temperature is therefore a greatly interdisciplinary topic, into the interface of the physico-chemistry, metallic and ceramic materials and mechanics. We propose in this work a finite element method for the simulation of EBPVD TBCs spallation. Our studies concern one of several systems that we call thermal barrier coatings, which are a Composite materials deposited in layers on the hot components to isolate them chemically and thermally at high temperatures. This is the last operational technology adapted on aircraft engines but it is still studied and not fully exploited.This comprehensive article describes the systems currently used and the problem of interaction between mechanical and environment in the turbine.

  3. Mechanistic Study on the Degradation of Thermal Barrier Coatings Induced by Volcanic Ash Deposition

    Science.gov (United States)

    Arai, Masayuki

    2017-08-01

    Thermal stress generated on thermal barrier coatings (TBCs) by volcanic ash (VA) deposition was assessed measuring the tip deflection of a multilayered beam structure as a function of temperature. The TBC in this study was deposited onto the surface of a blade utilized in a land-based gas turbine which is composed of 8 wt.%Y2O3-ZrO2/CoNiCrAlY on a Ni-based superalloy. The VA-deposited TBC sample was heated at 1453 K, and the effect of VA deposition on TBC delamination was examined in comparison with a TBC sample without VA deposition as a reference. On the basis of the VA attack damage mechanism which was investigated via the tip deflection measurement and a comprehensive microstructure examination, a damage-coupled constitutive model was proposed. The proposed model was based on the infiltration of the molten VA inside pores and phase transformations of yttria -tabilized zirconia in the TBC system. The numerical analysis results, which were simulated utilizing the finite element code installing the developed constitutive model, showed us that VA attack on the TBC sample induced near-interfacial cracks because of a significant increasing in the coating stress.

  4. Characterization of a rapid thermal anneal TiNxOy/TiSi2 contact barrier

    Science.gov (United States)

    Ho, V. Q.

    1989-07-01

    In this paper, the physical and electrical properties of a TiNxOy/TiSi2 dual layer contact barrier are reported. The TiNxOy/TiSi2 barrier was formed by rapidly annealing a Ti thin film on Si in an N2 ambient. During this process, the Ti film surface reacts with N2 to form a TiNxOy skin layer and the bulk of the Ti film reacts with Si to form an underlying TiSi2 layer. The influences of rapid thermal anneal (RTA) conditions on the TiNxOy layer were investigated by varying the RTA temperature from 600 to 1100° C and cycle duration from 30 to 100 s. It is found that the resulting TiNxOy and TiSi2 layer thicknesses are dependent on RTA temperature and the starting Ti thickness. For a starting Ti thickness of 500Å, 150Å thick TiNxOy and 800Å thick TiSi2 are obtained after an RTA at 900° C for 30 s. The TiNxOy thickness is limited by a fast diffusion of Si into Ti to form TiSi2. When a Ti film is deposited on SiO2, Ti starts to react with SiO2 from 600° C and a significant reduction of the SiO2 thickness is observed after an RTA at 900° C. The resulting layer is composed of a surface TiNxOy layer followed by a complex layer of titanium oxide and titanium suicide. In addition, when Ti is depos-ited on TiSi2, thicker TiNxOy and TiSi2 layers are obtained after RTA. This is because the TiSi2 layer retards the diffusion of Si from the underlying substrate into the Ti layer. NMOSFETs were fabricated using the TiNxOy/TiSi2 as a contact barrier formed by RTA at 900° C for 30 s and a significant reduction of contact resistance was obtained. In addition, electromigration test at a high current density indicated that a significant improvement in mean time to failure (MTF) has been obtained with the barrier.

  5. Westinghouse AP1000 advanced passive plant: design features and benefits

    Energy Technology Data Exchange (ETDEWEB)

    Walls, S.J. [British Nuclear Fuels plc, Seascale, Cumbria (United Kingdom); Cummins, W.E. [Westinghouse Electric Company, Pittsburgh, Pennsylvania (United States)

    2003-07-01

    The Westinghouse AP1000 Program is aimed at implementing the AP1000 plant to provide a further major improvement in plant economics while maintaining the passive safety advantages established by the AP600. An objective is to retain to the maximum extent possible the plant design of the AP600 so as to retain the licensing basis, cost estimate, construction schedule, modularization scheme, and the detailed design from the AP600 program. Westinghouse and the US Nuclear Regulatory Commission staff have embarked on a program to complete Design Certification for the AP1000 by 2004. A pre-certification review phase was completed in March 2002 and was successful in establishing the applicability of the AP600 test program and AP600 safety analysis codes to the AP1000 Design Certification. On March 28, 2002, Westinghouse submitted to US NRC the AP1000 Design Control Document and Probabilistic Risk Assessment, thereby initiating the formal design certification review process. The results presented in these documents verify the safety performance of the API 000 and conformance with US NRC licensing requirements. Plans are being developed for implementation of a series of AP1000 plants in the US. Key factors in this planning are the economics of AP1000, and the associated business model for licensing, constructing and operating these new plants. Similarly plans are being developed to get the AP1000 design reviewed for use in the UK. Part of this planning has been to examine the AP1000 design relative to anticipated UK safety and licensing issues. (author)

  6. Spectral Modeling of Residual Stress and Stored Elastic Strain Energy in Thermal Barrier Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Donegan, Sean; Rolett, Anthony

    2013-12-31

    Solutions to the thermoelastic problem are important for characterizing the response under temperature change of refractory systems. This work extends a spectral fast Fourier transform (FFT) technique to analyze the thermoelastic behavior of thermal barrier coatings (TBCs), with the intent of probing the local origins of failure in TBCs. The thermoelastic FFT (teFFT) approach allows for the characterization of local thermal residual stress and strain fields, which constitute the origins of failure in TBC systems. A technique based on statistical extreme value theory known as peaks-over-threshold (POT) is developed to quantify the extreme values ("hot spots") of stored elastic strain energy (i.e., elastic energy density, or EED). The resolution dependence of the teFFT method is assessed through a sensitivity study of the extreme values in EED. The sensitivity study is performed both for the local (point-by-point) eld distributions as well as the grain scale eld distributions. A convergence behavior to a particular distribution shape is demonstrated for the local elds. The grain scale fields are shown to exhibit a possible convergence to a maximum level of EED. To apply the teFFT method to TBC systems, 3D synthetic microstructures are created to approximate actual TBC microstructures. The morphology of the grains in each constituent layer as well as the texture is controlled. A variety of TBC materials, including industry standard materials and potential future materials, are analyzed using the teFFT. The resulting hot spots are quantified using the POT approach. A correlation between hot spots in EED and interface rumpling between constituent layers is demonstrated, particularly for the interface between the bond coat (BC) and the thermally grown oxide (TGO) layer.

  7. Erosion Performance of Gadolinium Zirconate-Based Thermal Barrier Coatings Processed by Suspension Plasma Spray

    Science.gov (United States)

    Mahade, Satyapal; Curry, Nicholas; Björklund, Stefan; Markocsan, Nicolaie; Nylén, Per; Vaßen, Robert

    2017-01-01

    7-8 wt.% Yttria-stabilized zirconia (YSZ) is the standard thermal barrier coating (TBC) material used by the gas turbines industry due to its excellent thermal and thermo-mechanical properties up to 1200 °C. The need for improvement in gas turbine efficiency has led to an increase in the turbine inlet gas temperature. However, above 1200 °C, YSZ has issues such as poor sintering resistance, poor phase stability and susceptibility to calcium magnesium alumino silicates (CMAS) degradation. Gadolinium zirconate (GZ) is considered as one of the promising top coat candidates for TBC applications at high temperatures (>1200 °C) due to its low thermal conductivity, good sintering resistance and CMAS attack resistance. Single-layer 8YSZ, double-layer GZ/YSZ and triple-layer GZdense/GZ/YSZ TBCs were deposited by suspension plasma spray (SPS) process. Microstructural analysis was carried out by scanning electron microscopy (SEM). A columnar microstructure was observed in the single-, double- and triple-layer TBCs. Phase analysis of the as-sprayed TBCs was carried out using XRD (x-ray diffraction) where a tetragonal prime phase of zirconia in the single-layer YSZ TBC and a cubic defect fluorite phase of GZ in the double and triple-layer TBCs was observed. Porosity measurements of the as-sprayed TBCs were made by water intrusion method and image analysis method. The as-sprayed GZ-based multi-layered TBCs were subjected to erosion test at room temperature, and their erosion resistance was compared with single-layer 8YSZ. It was shown that the erosion resistance of 8YSZ single-layer TBC was higher than GZ-based multi-layered TBCs. Among the multi-layered TBCs, triple-layer TBC was slightly better than double layer in terms of erosion resistance. The eroded TBCs were cold-mounted and analyzed by SEM.

  8. The Westinghouse Series 1000 Mobile Phone: Technology and applications

    Science.gov (United States)

    Connelly, Brian

    1993-01-01

    Mobile satellite communications will be popularized by the North American Mobile Satellite (MSAT) system. The success of the overall system is dependent upon the quality of the mobile units. Westinghouse is designing our unit, the Series 1000 Mobile Phone, with the user in mind. The architecture and technology aim at providing optimum performance at a low per unit cost. The features and functions of the Series 1000 Mobile Phone have been defined by potential MSAT users. The latter portion of this paper deals with who those users may be.

  9. The Development of HfO2-Rare Earth Based Oxide Materials and Barrier Coatings for Thermal Protection Systems

    Science.gov (United States)

    Zhu, Dongming; Harder, Bryan James

    2014-01-01

    Advanced hafnia-rare earth oxides, rare earth aluminates and silicates have been developed for thermal environmental barrier systems for aerospace propulsion engine and thermal protection applications. The high temperature stability, low thermal conductivity, excellent oxidation resistance and mechanical properties of these oxide material systems make them attractive and potentially viable for thermal protection systems. This paper will focus on the development of the high performance and high temperature capable ZrO2HfO2-rare earth based alloy and compound oxide materials, processed as protective coating systems using state-or-the-art processing techniques. The emphasis has been in particular placed on assessing their temperature capability, stability and suitability for advanced space vehicle entry thermal protection systems. Fundamental thermophysical and thermomechanical properties of the material systems have been investigated at high temperatures. Laser high-heat-flux testing has also been developed to validate the material systems, and demonstrating durability under space entry high heat flux conditions.

  10. Standard technical specifications, Westinghouse Plants: Specifications. Volume 1, Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-04-01

    This NUREG contains the improved Standard Technical Specifications (STS) for Westinghouse plants. Revision 1 incorporates the cumulative changes to Revision 0, which was published in September 1992. The changes reflected in Revision 1 resulted from the experience gained from license amendment applications to convert to these improved STS or to adopt partial improvements to existing technical specifications. This NUREG is the result of extensive public technical meetings and discussions between the Nuclear Regulatory Commission (NRC) staff and various nuclear power plant licensees, Nuclear Steam Supply System (NSSS) Owners Groups, specifically the Westinghouse Owners Group (WOG), NSSS vendors, and the Nuclear Energy Institute (NEI). The improved STS were developed based on the criteria in the Final Commission Policy Statement on Technical Specifications Improvements for Nuclear Power Reactors, dated July 22, 1993 (58 FR 39132). Licensees are encouraged to upgrade their technical specifications consistent with those criteria and conforming, to the extent practical and consistent with the licensing basis for the facility, to Revision 1 to the improved STS. The Commission continues to place the highest priority on requests for complete conversions to the improved STS. Licensees adopting portions of the improved STS to existing technical specifications should adopt all related requirements, as applicable, to achieve a high degree of standardization and consistency.

  11. Thick Thermal Barrier Coatings (TTBCs) for Low Emission, High Efficiency Diesel Engine Components

    Energy Technology Data Exchange (ETDEWEB)

    M. Brad Beardsley, Caterpillar Inc.; Dr. Darrell Socie, University of Illinois; Dr. Ed Redja, University of Illinois; Dr. Christopher Berndt, State University of New York at Stony Brook

    2006-03-02

    The objective of this program was to advance the fundamental understanding of thick thermal barrier coating (TTBC) systems for application to low heat rejection diesel engine combustion chambers. Previous reviews of thermal barrier coating technology concluded that the current level of understanding of coating system behavior is inadequate and the lack of fundamental understanding may impede the application of thermal barrier coating to diesel engines.(1) Areas of TTBC technology examined in this program include powder characteristics and chemistry; bond coating composition, coating design, microstructure and thickness as they affect properties, durability, and reliability; and TTBC "aging" effects (microstructural and property changes) under diesel engine operating conditions. Fifteen TTBC ceramic powders were evaluated. These powders were selected to investigate the effects of different chemistries, different manufacturing methods, lot-to-lot variations, different suppliers and varying impurity levels. Each of the fifteen materials has been sprayed using 36 parameters selected by a design of experiments (DOE) to determine the effects of primary gas (Ar and N2), primary gas flow rate, voltage, arc current, powder feed rate, carrier gas flow rate, and spraying distance. The deposition efficiency, density, and thermal conductivity of the resulting coatings were measured. A coating with a high deposition efficiency and low thermal conductivity is desired from an economic standpoint. An optimum combination of thermal conductivity and disposition efficiency was found for each lot of powder in follow-on experiments and disposition parameters were chosen for full characterization.(2) Strengths of the optimized coatings were determined using 4-point bending specimens. The tensile strength was determined using free-standing coatings made by spraying onto mild steel substrates which were subsequently removed by chemical etching. The compressive strengths of the coatings

  12. Novel Prospects for Plasma Spray-Physical Vapor Deposition of Columnar Thermal Barrier Coatings

    Science.gov (United States)

    Anwaar, Aleem; Wei, Lianglinag; Guo, Qian; Zhang, Baopeng; Guo, Hongbo

    2017-12-01

    Plasma spray-physical vapor deposition (PS-PVD) is an emerging coating technique that can produce columnar thermal barrier coatings from vapor phase. Feedstock treatment at the start of its trajectory in the plasma torch nozzle is important for such vapor-phase deposition. This study describes the effects of the plasma composition (Ar/He) on the plasma characteristics, plasma-particle interaction, and particle dynamics at different points spatially distributed inside the plasma torch nozzle. The results of calculations show that increasing the fraction of argon in the plasma gas mixture enhances the momentum and heat flow between the plasma and injected feedstock. For the plasma gas combination of 45Ar/45He, the total enthalpy transferred to a representative powder particle inside the plasma torch nozzle is highest ( 9828 kJ/kg). Moreover, due to the properties of the plasma, the contribution of the cylindrical throat, i.e., from the feed injection point (FIP) to the start of divergence (SOD), to the total transferred energy is 69%. The carrier gas flow for different plasma gas mixtures was also investigated by optical emission spectroscopy (OES) measurements of zirconium emissions. Yttria-stabilized zirconia (YSZ) coating microstructures were produced when using selected plasma gas compositions and corresponding carrier gas flows; structural morphologies were found to be in good agreement with OES and theoretical predictions. Quasicolumnar microstructure was obtained with porosity of 15% when applying the plasma composition of 45Ar/45He.

  13. On-Line Thermal Barrier Coating Monitoring for Real-Time Failure Protection and Life Maximization

    Energy Technology Data Exchange (ETDEWEB)

    Dennis H. LeMieux

    2005-10-01

    Under the sponsorship of the U. S. Department of Energy's National Energy Laboratory, Siemens Power Generation, Inc proposed a four year program titled, ''On-Line Thermal Barrier Coating (TBC) Monitor for Real-Time Failure Protection and Life Maximization'', to develop, build and install the first generation of an on-line TBC monitoring system for use on land-based advanced gas turbines (AGT). Federal deregulation in electric power generation has accelerated power plant owner's demand for improved reliability availability maintainability (RAM) of the land-based advanced gas turbines. As a result, firing temperatures have been increased substantially in the advanced turbine engines, and the TBCs have been developed for maximum protection and life of all critical engine components operating at these higher temperatures. Losing TBC protection can therefore accelerate the degradation of substrate components materials and eventually lead to a premature failure of critical component and costly unscheduled power outages. This program seeks to substantially improve the operating life of high cost gas turbine components using TBC; thereby, lowering the cost of maintenance leading to lower cost of electricity. Siemens Power Generation, Inc. has teamed with Indigo Systems, a supplier of state-of-the-art infrared camera systems, and Wayne State University, a leading research organization in the field of infrared non-destructive examination (NDE), to complete the program.

  14. Novel Prospects for Plasma Spray-Physical Vapor Deposition of Columnar Thermal Barrier Coatings

    Science.gov (United States)

    Anwaar, Aleem; Wei, Lianglinag; Guo, Qian; Zhang, Baopeng; Guo, Hongbo

    2017-09-01

    Plasma spray-physical vapor deposition (PS-PVD) is an emerging coating technique that can produce columnar thermal barrier coatings from vapor phase. Feedstock treatment at the start of its trajectory in the plasma torch nozzle is important for such vapor-phase deposition. This study describes the effects of the plasma composition (Ar/He) on the plasma characteristics, plasma-particle interaction, and particle dynamics at different points spatially distributed inside the plasma torch nozzle. The results of calculations show that increasing the fraction of argon in the plasma gas mixture enhances the momentum and heat flow between the plasma and injected feedstock. For the plasma gas combination of 45Ar/45He, the total enthalpy transferred to a representative powder particle inside the plasma torch nozzle is highest ( 9828 kJ/kg). Moreover, due to the properties of the plasma, the contribution of the cylindrical throat, i.e., from the feed injection point (FIP) to the start of divergence (SOD), to the total transferred energy is 69%. The carrier gas flow for different plasma gas mixtures was also investigated by optical emission spectroscopy (OES) measurements of zirconium emissions. Yttria-stabilized zirconia (YSZ) coating microstructures were produced when using selected plasma gas compositions and corresponding carrier gas flows; structural morphologies were found to be in good agreement with OES and theoretical predictions. Quasicolumnar microstructure was obtained with porosity of 15% when applying the plasma composition of 45Ar/45He.

  15. A Numerical Procedure to Obtain the Creep Parameters of the Thermal Barrier Coating

    Directory of Open Access Journals (Sweden)

    Shifeng Wen

    2014-05-01

    Full Text Available Three-point bending creep test was used to understand the creep behavior of typical thin film/substrate systems—thermal barrier coating (TBC systems. Firstly, a simplified model, which does not consider the local effect, has been set up to get an analytical relationship. The important result is that creep stress exponent of materials is equal to the creep load exponent of the steady-state deflection rate of BC specimens. Secondly, in order to consider the local effect of bending, the finite element method (FEM has been carried out. FEM calculation shows that there is a steady stage of the creep deflection under a constant applied load. And the exponent of the steady-state creep deflection rate to the applied load is found to be equal to the creep stress exponent of materials. The creep constant of the materials can be obtained by a set of trials with assumed creep constants of materials and can be finally determined by the best fit method. Finally, the finite element results show that the influences of the friction, the thickness of TBCs, and the modulus ratio of TBC to the substrate on stress distribution are important.

  16. Thermal Cycling Behavior of Thermal Barrier Coatings with MCrAlY Bond Coat Irradiated by High-Current Pulsed Electron Beam.

    Science.gov (United States)

    Cai, Jie; Lv, Peng; Guan, Qingfeng; Xu, Xiaojing; Lu, Jinzhong; Wang, Zhiping; Han, Zhiyong

    2016-11-30

    Microstructural modifications of a thermally sprayed MCrAlY bond coat subjected to high-current pulsed electron beam (HCPEB) and their relationships with thermal cycling behavior of thermal barrier coatings (TBCs) were investigated. Microstructural observations revealed that the rough surface of air plasma spraying (APS) samples was significantly remelted and replaced by many interconnected bulged nodules after HCPEB irradiation. Meanwhile, the parallel columnar grains with growth direction perpendicular to the coating surface were observed inside these bulged nodules. Substantial Y-rich Al2O3 bubbles and varieties of nanocrystallines were distributed evenly on the top of the modified layer. A physical model was proposed to describe the evaporation-condensation mechanism taking place at the irradiated surface for generating such surface morphologies. The results of thermal cycling test showed that HCPEB-TBCs presented higher thermal cycling resistance, the spalling area of which after 200 cycles accounted for only 1% of its total area, while it was about 34% for APS-TBCs. The resulting failure mode, i.e., in particular, a mixed delamination crack path, was shown and discussed. The irradiated effects including compact remelted surface, abundant nanoparticles, refined columnar grains, Y-rich alumina bubbles, and deformation structures contributed to the formation of a stable, continuous, slow-growing, and uniform thermally grown oxide with strong adherent ability. It appeared to be responsible for releasing stress and changing the cracking paths, and ultimately greatly improving the thermal cycling behavior of HCPEB-TBCs.

  17. Aircraft engine-mounted camera system for long wavelength infrared imaging of in-service thermal barrier coated turbine blades.

    Science.gov (United States)

    Markham, James; Cosgrove, Joseph; Scire, James; Haldeman, Charles; Agoos, Ian

    2014-12-01

    This paper announces the implementation of a long wavelength infrared camera to obtain high-speed thermal images of an aircraft engine's in-service thermal barrier coated turbine blades. Long wavelength thermal images were captured of first-stage blades. The achieved temporal and spatial resolutions allowed for the identification of cooling-hole locations. The software and synchronization components of the system allowed for the selection of any blade on the turbine wheel, with tuning capability to image from leading edge to trailing edge. Its first application delivered calibrated thermal images as a function of turbine rotational speed at both steady state conditions and during engine transients. In advance of presenting these data for the purpose of understanding engine operation, this paper focuses on the components of the system, verification of high-speed synchronized operation, and the integration of the system with the commercial jet engine test bed.

  18. Effect of thermal barrier coating with various blends of pumpkin seed oil methyl ester in DI diesel engine

    Science.gov (United States)

    Karthickeyan, V.; Balamurugan, P.

    2017-10-01

    The rise in oil prices, dependency on fossil fuels, degradation of non-renewable energy resources and global warming strives to find a low-carbon content alternative fuel to the conventional fuel. In the present work, Partially Stabilized Zirconia (PSZ) was used as a thermal barrier coating in piston head, cylinder head and intake and exhaust valves using plasma spray technique, which provided a rise in combustion chamber temperature. With the present study, the effects of thermal barrier coating on the blends of Pumpkin Seed Oil Methyl Ester (PSOME) were observed in both the coated and uncoated engine. Performance and emission characteristics of the PSOME in coated and uncoated engines were observed and compared. Increased thermal efficiency and reduced fuel consumption were observed for B25 and diesel in coated and uncoated engine. On comparing with the other biodiesel samples, B25 exhibited lower HC, NOx and smoke emissions in thermally coated engine than uncoated engine. After 100 h of operation, no anamolies were found in the thermally coated components except minor cracks were identified in the edges of the piston head.

  19. Experimental-calculation study of ion-plasma thermal barrier coatings for turbine blades made of intermetallic nickel superalloys

    Science.gov (United States)

    Budinovskii, S. A.; Matveev, P. V.; Zhivushkin, A. A.; Tikhomirova, E. A.; Belyaeva, L. A.; Balakin, S. M.

    2017-06-01

    The ion-plasma thermal barrier coatings deposited onto samples and blades made of intermetallic VKNA-1V and VKNA-25 alloys are tested in a laboratory. The external ceramic layer of the thermal barrier coatings (TBC) is formed by magnetron sputtering of zirconium alloy targets and has a columnar structure. The influence of NiCrAlY(Re, Ta, Hf) + AlNiY(Hf) + ZrYGdO TBC on the long-term strength at a test temperature of 1200°C and on the high-cycle fatigue at a temperature of 900°C is studied. Blades with TBC are subjected to thermal cycling tests in the temperature range 950 ↔ 400°C and 1050 ↔ 400°C during air cooling and in the range 950 ↔ 200°C during water cooling at 500 cycles. The temperature fields in the cross section of a blade airfoil during thermal cycling are calculated. The laws of formation of fracture zones and the development of thermal fatigue cracks under the conditions that are close to the operating conditions of nozzle TBC-containing blades are investigated.

  20. Standard technical specifications for Westinghouse pressurized water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, P.C.

    1979-07-01

    This Standard Technical Specification (STS) has been structured for the broadest possible use on Westinghouse plants currently being reviewed for an Operating License. Accordingly, the document contains specifications applicable to plants with (1) either 3 or 4 loops and (2) with and without loop stop valves. In addition, four separate and discrete containment specification sections are provided for each of the following containment types: Atmospheric, Ice Condenser, Sub-Atmospheric, and Dual. Optional specifications are provided for those features and systems which may be included in individual plant designs but are not generic in their scope of application. Alternate specifications are provided in a limited number of cases to cover situations where alternate specification requirements are necessary on a generic basis because of design differences. This revision of the STS does not typically include requirements which may be added or revised as a result of the NRC staff's further review of the Three Mile Island incident.

  1. Westinghouse Hanford Company operational environmental monitoring annual report, CY 1992

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, J.W.; Johnson, A.R.; McKinney, S.M.; Perkins, C.J.

    1993-07-01

    This document presents the results of the Westinghouse Hanford Company near-facility operational environmental monitoring for 1992 in the 100, 200/600, and 300/400 Areas of the Hanford Site, in south-central Washington State in 1992. Surveillance activities included sampling and analyses of ambient air, surface water, groundwater, sediments, soil, and biota. Also, external radiation measurements and radiological surveys were taken at waste disposal sites, radiologically controlled areas, and roads. These activities were conducted to assess and to control the impacts of nuclear facilities and waste sites on the workers and the local environment. Additionally, diffuse sources were monitored to determine compliance with Federal, State, and/or local regulations. In general, although impacts from nuclear facilities are still seen on the Hanford Site and are slightly elevated when compared to offsite, these impacts are less than in previous years.

  2. Confined space entry program for the Westinghouse Hanford Company

    Energy Technology Data Exchange (ETDEWEB)

    Cornell, T.M.

    1993-11-01

    To comply with anticipated OSHA regulatory requirements concerning Permit-Required Confined Spaces, Westinghouse Hanford Company (WHC) created a Confined Spaces Task Team. The primary focus of the task team was to prepare a formal Confined Space Entry (CSE) Program that would ensure full compliance with the anticipated OSHA requirements. A comprehensive training plan was also prepared and submitted for approval as soon as the new CSE Program was approved and released for implementation. On January 14, 1993, OSHA released their final ruling which contained several further changes, requiring the WHC Confined Space Entry Program and Training Plan to be revised. The revised training manual and lessons learned in establishing a Confined Space Entry Program are presented.

  3. Numerical modeling for preliminary design of the hydrogen production electrolyzer in the Westinghouse hybrid cycle

    Energy Technology Data Exchange (ETDEWEB)

    Jomard, F.; Feraud, J. P. [CEA Valrho, DTEC/SGCS/LGCI, F-30207 Bagnols Sur Ceze, (France); Caire, J. P. [ENSEEG, LEPMI, F-38402 St Martin Dheres, (France)

    2008-07-01

    The Westinghouse sulfur process decomposes water into hydrogen and oxygen in several steps. This process requires a high-temperature thermal source, which could ideally be a fourth-generation nuclear reactor for recycling compounds. The process consists of producing hydrogen in a specific electrolyzer where protons are reduced at the cathode while an oxidation reaction, in which sulfur dioxide forms sulfuric acid, takes place in the anode compartment. This type of reaction enables mass hydrogen production at a very low cell voltage because the thermodynamic oxidation potential of SO{sub 2}/H{sub 2}SO{sub 4} is 0.17 V, compared with 1.23 V for the common electrolysis of water by H{sub 2}O/O{sub 2} oxidation. This article describes the electrical/thermal coupling of an individual filter press electrolysis cell for the preliminary design of a future test pilot. Solving coupled equations describing heat transfer and electrokinetics in the presence of forced convective flow of a two-phase electrolyte allows charge and heat transfer to be predicted for different configurations. (authors)

  4. AN ANALYSIS OF THE THERMAL AND MECHANICAL BEHAVIOR OF ENGINEERED BARRIERS IN A HIGH-LEVEL RADIOACTIVE WASTE REPOSITORY

    Directory of Open Access Journals (Sweden)

    S. KWON

    2013-02-01

    Full Text Available Adequate design of engineered barriers, including canister, buffer and backfill, is important for the safe disposal of high-level radioactive waste. Three-dimensional computer simulations were carried out under different condition to examine the thermal and mechanical behavior of engineered barriers and rock mass. The research looked at five areas of importance, the effect of the swelling pressure, water content of buffer, density of compacted bentonite, emplacement type and the selection of failure criteria. The results highlighted the need to consider tensile stress in the outer shell of a canister due to thermal expansion of the canister and the swelling pressure from the buffer for a more reliable design of an underground repository system. In addition, an adequate failure criterion should be used for the buffer and backfill.

  5. Thermal damping effect due to a green barrier which includes Arundo donax as bioclimatic element in buildings

    Directory of Open Access Journals (Sweden)

    P. Rodríguez-Salinas

    2017-09-01

    Full Text Available Among the main environmental impacts of the operation of residential buildings are those due to greenhouse gases generation as a result of electric consumption of air conditioning systems. The use of vegetation systems in residential buildings represents an alternative to reduce this energy consumption. Green vegetation systems barriers are often used as protection against winds, but recently they are also being used as acoustic dampers. This work explores their use as thermal insulation systems for buildings. Specifically, we report the behavior of an Arundo donax green barrier as a bioclimatic element. The results are analyzed based on indoor and outdoor temperature measurement in prototype buildings, in function of the green barrier presence. Additionally Arundo donax transpiration under extreme environmental conditions was determined.

  6. Phase Stability and Thermal Conductivity of Composite Environmental Barrier Coatings on SiC/SiC Ceramic Matrix Composites

    Science.gov (United States)

    Benkel, Samantha; Zhu, Dongming

    2011-01-01

    Advanced environmental barrier coatings are being developed to protect SiC/SiC ceramic matrix composites in harsh combustion environments. The current coating development emphasis has been placed on the significantly improved cyclic durability and combustion environment stability in high-heat-flux and high velocity gas turbine engine environments. Environmental barrier coating systems based on hafnia (HfO2) and ytterbium silicate, HfO2-Si nano-composite bond coat systems have been processed and their stability and thermal conductivity behavior have been evaluated in simulated turbine environments. The incorporation of Silicon Carbide Nanotubes (SiCNT) into high stability (HfO2) and/or HfO2-silicon composite bond coats, along with ZrO2, HfO2 and rare earth silicate composite top coat systems, showed promise as excellent environmental barriers to protect the SiC/SiC ceramic matrix composites.

  7. Technical and Economical Aspects of Current Thermal Barrier Coating Systems for Gas Turbine Engines by Thermal Spray and EBPVD: A Review

    Science.gov (United States)

    Feuerstein, Albert; Knapp, James; Taylor, Thomas; Ashary, Adil; Bolcavage, Ann; Hitchman, Neil

    2008-06-01

    The most advanced thermal barrier coating (TBC) systems for aircraft engine and power generation hot section components consist of electron beam physical vapor deposition (EBPVD) applied yttria-stabilized zirconia and platinum modified diffusion aluminide bond coating. Thermally sprayed ceramic and MCrAlY bond coatings, however, are still used extensively for combustors and power generation blades and vanes. This article highlights the key features of plasma spray and HVOF, diffusion aluminizing, and EBPVD coating processes. The coating characteristics of thermally sprayed MCrAlY bond coat as well as low density and dense vertically cracked (DVC) Zircoat TBC are described. Essential features of a typical EBPVD TBC coating system, consisting of a diffusion aluminide and a columnar TBC, are also presented. The major coating cost elements such as material, equipment and processing are explained for the different technologies, with a performance and cost comparison given for selected examples.

  8. Volatile organic compounds (VOCs) removal in non-thermal plasma double dielectric barrier discharge reactor.

    Science.gov (United States)

    Mustafa, Muhammad Farooq; Fu, Xindi; Liu, Yanjun; Abbas, Yawar; Wang, Hongtao; Lu, Wenjing

    2018-04-05

    Non-thermal plasma (NTP) an emerging technology to treat volatile organic compounds (VOCs) present in unhygienic point source air streams. In present study, double dielectric barrier discharge (DDBD) reactors were used for the first time to evaluate the removal efficiency of VOCs mixture of different nature at constant experimental conditions (input power 16-65.8 W, VOCs mixture feeding rate 1-6 L/min, 100-101 ppm inlet concentration of individual VOC). Reactor A and B with discharge gap at 6 mm and 3 mm respectively, were used in current study. When treated at an input power of 53.7 W with gas feeding rate of 1 L/min in DDBD reactor A, removal efficiency of the VOCs were: tetrachloroethylene (100%), toluene (100%), trichloroethylene (100%), benzene (100%), ethyl acetate (100%) and carbon disulfide (88.30%); whereas in reactor B, the removal efficiency of all VOCs were 100%. Plasma-catalyst (Pt-Sn/Al 2 O 3 , BaTiO 3 and HZSM-5) synergistic effect on VOCs removal efficiency was also investigated. Highest removal efficiency i.e 100% was observed for each compound with BaTiO 3 and HZSM-5 at an input power 65.8 W. However, integrating NTP with BaTiO 3 and HZSM-5 leads to enhanced removal performance of VOCs mixture with high activity, increase in energy efficiency and suppression of unwanted byproducts. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Elastically cooperative activated barrier hopping theory of relaxation in viscous fluids. II. Thermal liquids.

    Science.gov (United States)

    Mirigian, Stephen; Schweizer, Kenneth S

    2014-05-21

    Building on the elastically collective nonlinear Langevin equation theory developed for hard spheres in Paper I, we propose and implement a quasi-universal theory for the alpha relaxation of thermal liquids based on mapping them to an effective hard sphere fluid via the dimensionless compressibility. The result is a zero adjustable parameter theory that can quantitatively address in a unified manner the alpha relaxation time over 14 or more decades. The theory has no singularities above zero Kelvin, and relaxation in the equilibrium low temperature limit is predicted to be of a roughly Arrhenius form. The two-barrier (local cage and long range collective elastic) description results in a rich dynamic behavior including apparent Arrhenius, narrow crossover, and deeply supercooled regimes, and multiple characteristic or crossover times and temperatures of clear physical meaning. Application of the theory to nonpolar molecules, alcohols, rare gases, and liquids metals is carried out. Overall, the agreement with experiment is quite good for the temperature dependence of the alpha time, plateau shear modulus, and Boson-like peak frequency for van der Waals liquids, though less so for hydrogen-bonding molecules. The theory predicts multiple growing length scales upon cooling, which reflect distinct aspects of the coupled local hopping and cooperative elastic physics. Calculations of the growth with cooling of an activation volume, which is strongly correlated with a measure of dynamic cooperativity, agree quantitatively with experiment. Comparisons with elastic, entropy crisis, dynamic facilitation, and other approaches are performed, and a fundamental basis for empirically extracted crossover temperatures is established. The present work sets the stage for addressing distinctive glassy phenomena in polymer melts, and diverse liquids under strong confinement.

  10. Combined Experimental and Numerical Simulations of Thermal Barrier Coated Turbine Blades Erosion

    Science.gov (United States)

    Hamed, Awate; Tabakoff, Widen; Swar, Rohan; Shin, Dongyun; Woggon, Nthanial; Miller, Robert

    2013-01-01

    A combined experimental and computational study was conducted to investigate the erosion of thermal barrier coated (TBC) blade surfaces by alumina particles ingestion in a single stage turbine. In the experimental investigation, tests of particle surface interactions were performed in specially designed tunnels to determine the erosion rates and particle restitution characteristics under different impact conditions. The experimental results show that the erosion rates increase with increased impingement angle, impact velocity and temperature. In the computational simulations, an Euler-Lagrangian two stage approach is used in obtaining numerical solutions to the three-dimensional compressible Reynolds Averaged Navier-Stokes equations and the particles equations of motion in each blade passage reference frame. User defined functions (UDF) were developed to represent experimentally-based correlations for particle surface interaction models which were employed in the three-dimensional particle trajectory simulations to determine the particle rebound characteristics after each surface impact. The experimentally based erosion UDF model was used to predict the TBC erosion rates on the turbine blade surfaces based on the computed statistical data of the particles impact locations, velocities and angles relative to the blade surface. Computational results are presented for the predicted TBC blade erosion in a single stage commercial APU turbine, for a NASA designed automotive turbine, and for the NASA turbine scaled for modern rotorcraft operating conditions. The erosion patterns in the turbines are discussed for uniform particle ingestion and for particle ingestion concentrated in the inner and outer 5 percent of the stator blade span representing the flow cooling the combustor liner.

  11. Method and Process Development of Advanced Atmospheric Plasma Spraying for Thermal Barrier Coatings

    Science.gov (United States)

    Mihm, Sebastian; Duda, Thomas; Gruner, Heiko; Thomas, Georg; Dzur, Birger

    2012-06-01

    Over the last few years, global economic growth has triggered a dramatic increase in the demand for resources, resulting in steady rise in prices for energy and raw materials. In the gas turbine manufacturing sector, process optimizations of cost-intensive production steps involve a heightened potential of savings and form the basis for securing future competitive advantages in the market. In this context, the atmospheric plasma spraying (APS) process for thermal barrier coatings (TBC) has been optimized. A constraint for the optimization of the APS coating process is the use of the existing coating equipment. Furthermore, the current coating quality and characteristics must not change so as to avoid new qualification and testing. Using experience in APS and empirically gained data, the process optimization plan included the variation of e.g. the plasma gas composition and flow-rate, the electrical power, the arrangement and angle of the powder injectors in relation to the plasma jet, the grain size distribution of the spray powder and the plasma torch movement procedures such as spray distance, offset and iteration. In particular, plasma properties (enthalpy, velocity and temperature), powder injection conditions (injection point, injection speed, grain size and distribution) and the coating lamination (coating pattern and spraying distance) are examined. The optimized process and resulting coating were compared to the current situation using several diagnostic methods. The improved process significantly reduces costs and achieves the requirement of comparable coating quality. Furthermore, a contribution was made towards better comprehension of the APS of ceramics and the definition of a better method for future process developments.

  12. Biomimetic thermal barrier coating in jet engine to resist volcanic ash deposition

    Science.gov (United States)

    Song, Wenjia; Major, Zsuzsanna; Schulz, Uwe; Muth, Tobias; Lavallée, Yan; Hess, Kai-Uwe; Dingwell, Donald B.

    2017-04-01

    The threat of volcanic ash to aviation safety is attracting extensive attention when several commercial jet aircraft were damaged after flying through volcanic ash clouds from the May 1980 eruptions of Mount St. Helen in Washington, U.S. and especially after the air traffic disruption in 2010 Eyjafjallajökull eruption. A major hazard presented by volcanic ash to aircraft is linked to the wetting and spreading of molten ash droplets on engine component surfaces. Due to the fact ash has a lower melting point, around 1100 °C, than the gas temperature in the hot section (between 1400 to 2000 °C), this cause the ash to melt and potentially stick to the internal components (e.g., combustor and turbine blades), this cause the ash to melt and potentially stick to the internal components of the engine creating, substantial damage or even engine failure after ingestion. Here, inspiring form the natural surface of lotus leaf (exhibiting extreme water repellency, known as 'lotus effect'), we firstly create the multifunctional surface thermal barrier coatings (TBCs) by producing a hierarchical structure with femtosecond laser pulses. In detail, we investigate the effect of one of primary femtosecond laser irradiation process parameter (scanning speed) on the hydrophobicity of water droplets onto the two kinds of TBCs fabricated by electron-beam physical vapor deposition (EB-PVD) and air plasma spray (APS), respectively as well as their corresponding to morphology. It is found that, comparison with the original surface (without femtosecond laser ablation), all of the irradiated samples demonstrate more significant hydrophobic properties due to nanostructuring. On the basis of these preliminary room-temperature results, the wettability of volcanic ash droplets will be analysed at the high temperature to constrain the potential impact of volcanic ash on the jet engines.

  13. Effect of Damage Processes on Spallation Life in Thermal Barrier Coatings

    National Research Council Canada - National Science Library

    Newaz, Golam M

    2001-01-01

    .... TBCs consist of an outer ceramic layer that provides good thermal insulation due to the low thermal conductivity of the ceramic used, and the inner metallic bond coat layer that provides needed...

  14. Combined Effects of JP-8 Fuel and Ceramic Thermal Barrier Coatings on the Performance and Emissions of a DI Diesel Engine

    National Research Council Canada - National Science Library

    Klett, David

    1999-01-01

    .... The experiments were conducted on a Ricardo Hydra single-cylinder DI diesel engine. Thin ceramic thermal barrier coatings were applied to various combustion chamber surfaces including the piston crown, cylinder head, and cylinder liner...

  15. Combined Effects of JP-8 Fuel and Ceramic Thermal Barrier Coatings on the Performance and Emissions of a DI Diesel Engine

    National Research Council Canada - National Science Library

    Klett, David

    1999-01-01

    An experimental study was conducted on the combined effects of using JP-8 Fuel in conjunction with thin thermal barrier coatings on the specific fuel consumption and emissions of UHC, NO, and smoke of a DI diesel engine...

  16. 77 FR 16077 - License Amendment Request From Westinghouse Electric Company, LLC, Hematite Decommissioning Project

    Science.gov (United States)

    2012-03-19

    ... From the Federal Register Online via the Government Publishing Office ] NUCLEAR REGULATORY COMMISSION License Amendment Request From Westinghouse Electric Company, LLC, Hematite Decommissioning Project AGENCY: Nuclear Regulatory Commission. ACTION: License amendment request; opportunity to provide...

  17. Coral Symbiodinium Community Composition Across the Belize Mesoamerican Barrier Reef System is Influenced by Host Species and Thermal Variability.

    Science.gov (United States)

    Baumann, J H; Davies, S W; Aichelman, H E; Castillo, K D

    2017-11-02

    Reef-building corals maintain a symbiotic relationship with dinoflagellate algae of the genus Symbiodinium, and this symbiosis is vital for the survival of the coral holobiont. Symbiodinium community composition within the coral host has been shown to influence a coral's ability to resist and recover from stress. A multitude of stressors including ocean warming, ocean acidification, and eutrophication have been linked to global scale decline in coral health and cover in recent decades. Three distinct thermal regimes (highTP, modTP, and lowTP) following an inshore-offshore gradient of declining average temperatures and thermal variation were identified on the Belize Mesoamerican Barrier Reef System (MBRS). Quantitative metabarcoding of the ITS-2 locus was employed to investigate differences and similarities in Symbiodinium genetic diversity of the Caribbean corals Siderastrea siderea, S. radians, and Pseudodiploria strigosa between the three thermal regimes. A total of ten Symbiodinium lineages were identified across the three coral host species. S. siderea was associated with distinct Symbiodinium communities; however, Symbiodinium communities of its congener, S. radians and P. strigosa, were more similar to one another. Thermal regime played a role in defining Symbiodinium communities in S. siderea but not S. radians or P. strigosa. Against expectations, Symbiodinium trenchii, a symbiont known to confer thermal tolerance, was dominant only in S. siderea at one sampled offshore site and was rare inshore, suggesting that coral thermal tolerance in more thermally variable inshore habitats is achieved through alternative mechanisms. Overall, thermal parameters alone were likely not the only primary drivers of Symbiodinium community composition, suggesting that environmental variables unrelated to temperature (i.e., light availability or nutrients) may play key roles in structuring coral-algal communities in Belize and that the relative importance of these

  18. Direct analysis of anabolic steroids in urine using Leidenfrost phenomenon assisted thermal desorption-dielectric barrier discharge ionization mass spectrometry.

    Science.gov (United States)

    Saha, Subhrakanti; Mandal, Mridul Kanti; Nonami, Hiroshi; Hiraoka, Kenzo

    2014-08-11

    Rapid detection of trace level anabolic steroids in urine is highly desirable to monitor the consumption of performance enhancing anabolic steroids by athletes. The present article describes a novel strategy for identifying the trace anabolic steroids in urine using Leidenfrost phenomenon assisted thermal desorption (LPTD) coupled to dielectric barrier discharge (DBD) ionization mass spectrometry. Using this method the steroid molecules are enriched within a liquid droplet during the thermal desorption process and desorbed all-together at the last moment of droplet evaporation in a short time domain. The desorbed molecules were ionized using a dielectric barrier discharge ion-source in front of the mass spectrometer inlet at open atmosphere. This process facilitates the sensitivity enhancement with several orders of magnitude compared to the thermal desorption at a lower temperature. The limits of detection (LODs) of various steroid molecules were found to be in the range of 0.05-0.1 ng mL(-1) for standard solutions and around two orders of magnitude higher for synthetic urine samples. The detection limits of urinary anabolic steroids could be lowered by using a simple and rapid dichloromethane extraction technique. The analytical figures of merit of this technique were evaluated at open atmosphere using suitable internal standards. The technique is simple and rapid for high sensitivity and high throughput screening of anabolic steroids in urine. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Gas seal for an in situ oil shale retort and method of forming thermal barrier

    Science.gov (United States)

    Burton, III, Robert S.

    1982-01-01

    A gas seal is provided in an access drift excavated in a subterranean formation containing oil shale. The access drift is adjacent an in situ oil shale retort and is in gas communication with the fragmented permeable mass of formation particles containing oil shale formed in the in situ oil shale retort. The mass of formation particles extends into the access drift, forming a rubble pile of formation particles having a face approximately at the angle of repose of fragmented formation. The gas seal includes a temperature barrier which includes a layer of heat insulating material disposed on the face of the rubble pile of formation particles and additionally includes a gas barrier. The gas barrier is a gas-tight bulkhead installed across the access drift at a location in the access drift spaced apart from the temperature barrier.

  20. Effect of Suspension Plasma-Sprayed YSZ Columnar Microstructure and Bond Coat Surface Preparation on Thermal Barrier Coating Properties

    Science.gov (United States)

    Bernard, Benjamin; Quet, Aurélie; Bianchi, Luc; Schick, Vincent; Joulia, Aurélien; Malié, André; Rémy, Benjamin

    2017-08-01

    Suspension plasma spraying (SPS) is identified as promising for the enhancement of thermal barrier coating (TBC) systems used in gas turbines. Particularly, the emerging columnar microstructure enabled by the SPS process is likely to bring about an interesting TBC lifetime. At the same time, the SPS process opens the way to a decrease in thermal conductivity, one of the main issues for the next generation of gas turbines, compared to the state-of-the-art deposition technique, so-called electron beam physical vapor deposition (EB-PVD). In this paper, yttria-stabilized zirconia (YSZ) coatings presenting columnar structures, performed using both SPS and EB-PVD processes, were studied. Depending on the columnar microstructure readily adaptable in the SPS process, low thermal conductivities can be obtained. At 1100 °C, a decrease from 1.3 W m-1 K-1 for EB-PVD YSZ coatings to about 0.7 W m-1 K-1 for SPS coatings was shown. The higher content of porosity in the case of SPS coatings increases the thermal resistance through the thickness and decreases thermal conductivity. The lifetime of SPS YSZ coatings was studied by isothermal cyclic tests, showing equivalent or even higher performances compared to EB-PVD ones. Tests were performed using classical bond coats used for EB-PVD TBC coatings. Thermal cyclic fatigue performance of the best SPS coating reached 1000 cycles to failure on AM1 substrates with a β-(Ni,Pt)Al bond coat. Tests were also performed on AM1 substrates with a Pt-diffused γ-Ni/γ'-Ni3Al bond coat for which more than 2000 cycles to failure were observed for columnar SPS YSZ coatings. The high thermal compliance offered by both the columnar structure and the porosity allowed the reaching of a high lifetime, promising for a TBC application.

  1. Acetylated rice starches films with different levels of amylose: Mechanical, water vapor barrier, thermal, and biodegradability properties.

    Science.gov (United States)

    Colussi, Rosana; Pinto, Vânia Zanella; El Halal, Shanise Lisie Mello; Biduski, Bárbara; Prietto, Luciana; Castilhos, Danilo Dufech; Zavareze, Elessandra da Rosa; Dias, Alvaro Renato Guerra

    2017-04-15

    Biodegradable films from native or acetylated starches with different amylose levels were prepared. The films were characterized according to the mechanical, water vapor barrier, thermal, and biodegradability properties. The films from acetylated high amylose starches had higher moisture content and water solubility than the native high amylose starch film. However, the acetylation did not affect acid solubility of the films, regardless of the amylose content. Films made from high and medium amylose rice starches were obtained; however low amylose rice starches, whether native or acetylated, did not form films with desirable characteristics. The acetylation decreased the tensile strength and increased the elongation of the films. The acetylated starch-based films had a lower decomposition temperature and higher thermal stability than native starch films. Acetylated starches films exhibited more rapid degradation as compared with the native starches films. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Alyssum homolocarpum seed gum-polyvinyl alcohol biodegradable composite film: Physicochemical, mechanical, thermal and barrier properties.

    Science.gov (United States)

    Monjazeb Marvdashti, Leila; Koocheki, Arash; Yavarmanesh, Masoud

    2017-01-02

    Films made from Alyssum homolocarpum seeds gum (AHSG) have poor mechanical and barrier (to oxygen) properties. In the present study poly vinyl alcohol (PVA) was used to improve the physicochemical properties of AHSG films. Results indicated that the addition of PVA significantly increased the moisture content, solubility, elongation at break (EB) and transparency while it decreased the density, oxygen permeability, chroma, water contact angle and Young modulus of AHSG based films. Films with higher AHSG to PVA ratios had lower water vapor permeability (WVP). The light barrier measurements presented low values of transparency at 600nm for PVA/AHSG films, indicating that films were very transparent while they had excellent barrier properties against UV light. Results for FTIR, DSC and SEM showed a clear interaction between PVA and AHSG, forming a new material. These results indicated that PVA/AHSG blend films had good compatibility. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Delamination Mechanisms of Thermal and Environmental Barrier Coatings on SiC/SiC Ceramic Matrix Composites

    Science.gov (United States)

    Zhu, Dongming; Choi, Sung R.; Lee, Kang N.; Miller, Robert A.

    2003-01-01

    Advanced ceramic thermal harrier coatings will play an increasingly important role In future gas turbine engines because of their ability to effectively protect the engine components and further raise engine temperatures. However, the coating durability issue remains a major concern with the ever-increasing temperature requirements. In this paper, thermal cyclic response and delamination failure modes of a ZrO2-8wt%Y2O3 and mullite/BSAS thermaVenvironmenta1 barrier coating system on SiC/SiC ceramic matrix composites were investigated using a laser high-heat-flux technique. The coating degradation and delamination processes were monitored in real time by measuring coating apparent conductivity changes during the cyclic tests under realistic engine temperature and stress gradients, utilizing the fact that delamination cracking causes an apparent decrease in the measured thermal conductivity. The ceramic coating crack initiation and propagation driving forces under the cyclic thermal loads, in conjunction with the mechanical testing results, will be discussed.

  4. Cooling Effectiveness Measurements for Air Film Cooling of Thermal Barrier Coated Surfaces in a Burner Rig Environment Using Phosphor Thermometry

    Science.gov (United States)

    Eldridge, Jeffrey I.; Shyam, Vikram; Wroblewski, Adam C.; Zhu, Dongming; Cuy, Michael D.; Wolfe, Douglas E.

    2016-01-01

    While the effects of thermal barrier coating (TBC) thermal protection and air film cooling effectiveness are usually studied separately, their contributions to combined cooling effectiveness are interdependent and are not simply additive. Therefore, combined cooling effectiveness must be measured to achieve an optimum balance between TBC thermal protection and air film cooling. In this investigation, surface temperature mapping was performed using recently developed Cr-doped GdAlO3 phosphor thermometry. Measurements were performed in the NASA GRC Mach 0.3 burner rig on a TBC-coated plate using a scaled up cooling hole geometry where both the mainstream hot gas temperature and the blowing ratio were varied. Procedures for surface temperature and cooling effectiveness mapping of the air film-cooled TBC-coated surface are described. Applications are also shown for an engine component in both the burner rig test environment as well as an engine afterburner environment. The effects of thermal background radiation and flame chemiluminescence on the measurements are investigated, and advantages of this method over infrared thermography as well as the limitations of this method for studying air film cooling are discussed.

  5. Westinghouse Small Modular Reactor balance of plant and supporting systems design

    Energy Technology Data Exchange (ETDEWEB)

    Memmott, M. J.; Stansbury, C.; Taylor, C. [Westinghouse Electric Company LLC, 600 Cranberry Woods Drive, Cranberry Twp. PA 16066 (United States)

    2012-07-01

    The Westinghouse Small Modular Reactor (SMR) is an 800 MWt (>225 MWe) integral pressurized water reactor (iPWR), in which all of the components typically associated with the nuclear steam supply system (NSSS) of a nuclear power plant are incorporated within a single reactor pressure vessel. This paper is the second in a series of four papers which describe the design and functionality of the Westinghouse SMR. It focuses, in particular, upon the supporting systems and the balance of plant (BOP) designs of the Westinghouse SMR. Several Westinghouse SMR systems are classified as safety, and are critical to the safe operation of the Westinghouse SMR. These include the protection and monitoring system (PMS), the passive core cooling system (PXS), and the spent fuel cooling system (SFS) including pools, valves, and piping. The Westinghouse SMR safety related systems include the instrumentation and controls (I and C) as well as redundant and physically separated safety trains with batteries, electrical systems, and switch gears. Several other incorporated systems are non-safety related, but provide functions for plant operations including defense-in-depth functions. These include the chemical volume control system (CVS), heating, ventilation and cooling (HVAC) systems, component cooling water system (CCS), normal residual heat removal system (RNS) and service water system (SWS). The integrated performance of the safety-related and non-safety related systems ensures the safe and efficient operation of the Westinghouse SMR through various conditions and transients. The turbine island consists of the turbine, electric generator, feedwater and steam systems, moisture separation systems, and the condensers. The BOP is designed to minimize assembly time, shipping challenges, and on-site testing requirements for all structures, systems, and components. (authors)

  6. Processing and Deposition of Nanocrystalline Oxide Composites for Thermal Barrier Coatings

    National Research Council Canada - National Science Library

    Ying, Jackie

    2000-01-01

    .... Electrophoretic deposition was used to coat the nanocomposite powders onto nickel substrates. The effect of alumina content, powder calcination temperature, and film thickness on the thermal stability of zirconia-based coatings was examined...

  7. Design and optimization of coating structure for the thermal barrier coatings fabricated by atmospheric plasma spraying via finite element method

    Directory of Open Access Journals (Sweden)

    L. Wang

    2014-06-01

    Full Text Available The first prerequisite for fabricating the thermal barrier coatings (TBCs with excellent performance is to find an optimized coating structure with high thermal insulation effect and low residual stress. This paper discusses the design and optimization of a suitable coating structure for the TBCs prepared by atmospheric plasma spraying (APS using the finite element method. The design and optimization processes comply with the rules step by step, as the structure develops from a simple to a complex one. The research results indicate that the suitable thicknesses of the bond-coating and top-coating are 60–120 μm and 300–420 μm, respectively, for the single ceramic layer YSZ/NiCoCrAlY APS-TBC. The embedded interlayer (50 wt.%YSZ + 50 wt.%NiCoCrAlY will further reduce the residual stress without sacrificing the thermal insulation effect. The double ceramic layer was further considered which was based on the single ceramic layer TBC. The embedded interlayer and the upper additional ceramic layer will have a best match between the low residual stress and high thermal insulation effect. Finally, the optimized coating structure was obtained, i.e., the La2Ce2O7(LC/YSZ/Interlayer/NiCoCrAlY coating structure with appropriate layer thickness is the best choice. The effective thermal conductivity of this optimized LC/YSZ/IL/BL TBC is 13.2% lower than that of the typical single ceramic layer YSZ/BL TBC.

  8. Experimental investigation of thermal barrier (8YSZ-TiO2-Al2O3 coated piston used in direct injection compression ignition engine

    Directory of Open Access Journals (Sweden)

    Muthusamy Jayaram

    2016-01-01

    Full Text Available Thermal barrier coatings are becoming increasingly important in providing protection from high temperature degradation for heat engine components and allow further increase in engine temperatures for higher efficiency. The main objective of this research work is to experimentally investigate the air plasma sprayed yttria stabilized zirconia with addition of titanium oxide and aluminum oxide thermal barrier coating on Al-13% Si piston material. The mechanical properties of the coated and uncoated samples were comparatively analyzed. The test revealed that hardness values of coated samples are ten times higher than the hardness values of uncoated samples. The microstructure and surface morphology of the coating were evaluated by scanning electron microscopy. The delamination behaviour of thermal barrier coating was evaluated by thermal cycle test. Finally, the performance test of the coated and uncoated engine was evaluated with the same engine operating conditions. The brake thermal efficiency is increased by 5.99%. The brake specific fuel consumption was decreased by 0.06 kg/kWh, in TBC engine with 8YSZ + Al2O3 + TiO2. The CO and HC was greatly decreased in thermal barrier coating engine. There was the greater reduction of NOx is observed due to coating because of nitrogen has absorbed by zirconia.

  9. Monitoring Delamination of Thermal Barrier Coating During Interrupted High-Heat Flux Laser Testing Using Upconversion Luminescence Imaging

    Science.gov (United States)

    Eldridge, Jeffrey I.; Zhu, Dongming; Wolfe, Douglas E.

    2011-01-01

    Upconversion luminescence imaging of thermal barrier coatings (TBCs) has been shown to successfully monitor TBC delamination progression during interrupted furnace cycling. However, furnace cycling does not adequately model engine conditions where TBC-coated components are subjected to significant heat fluxes that produce through-thickness temperature gradients that may alter both the rate and path of delamination progression. Therefore, new measurements are presented based on luminescence imaging of TBC-coated specimens subjected to interrupted high-heat-flux laser cycling exposures that much better simulate the thermal gradients present in engine conditions. The TBCs tested were deposited by electron-beam physical vapor deposition (EB-PVD) and were composed of 7wt% yttria-stabilized zirconia (7YSZ) with an integrated delamination sensing layer composed of 7YSZ co-doped with erbium and ytterbium (7YSZ:Er,Yb). The high-heat-flux exposures that produce the desired through-thickness thermal gradients were performed using a high power CO2 laser operating at a wavelength of 10.6 microns. Upconversion luminescence images revealed the debond progression produced by the cyclic high-heat-flux exposures and these results were compared to that observed for furnace cycling.

  10. Design of a Nickel-Based Bond-Coat Alloy for Thermal Barrier Coatings on Copper Substrates

    Directory of Open Access Journals (Sweden)

    Torben Fiedler

    2014-11-01

    Full Text Available To increase the lifetime of rocket combustion chambers, thermal barrier coatings (TBC may be applied on the copper chamber wall. Since standard TBC systems used in gas turbines are not suitable for rocket-engine application and fail at the interface between the substrate and bond coat, a new bond-coat material has to be designed. This bond-coat material has to be chemically compatible to the copper substrate to improve the adhesion and needs a coefficient of thermal expansion close to that of copper to reduce thermal stresses. One approach to achieve this is to modify the standard NiCrAlY alloy used in gas turbines by adding copper. In this work, the influence of copper on the microstructure of NiCrAlY-alloys is investigated with thermodynamical calculations, optical microscopy, SEM, EDX and calorimetry. Adding copper leads to the formation of a significant amount of \\(\\beta\\ and \\(\\alpha\\ Reducing the aluminum and chromium content leads furthermore to a two-phase fcc microstructure.

  11. BEACON{sup TM} Core Monitoring and Analysis for Operations of the Westinghouse AP1000

    Energy Technology Data Exchange (ETDEWEB)

    Skidmore, Sam A.; Krieg, David J. [Westinghouse Electric Company, Nuclear Fuel Division, P.O.Box 355, Pittsburgh, PA, 15230 (United States)

    2009-06-15

    The Westinghouse AP1000 is a highly advanced Generation 3 pressurized water reactor (PWR). The reactor control strategy is considerably different from today's Westinghouse PWRs. AP1000 reactor control utilizes mechanical shim (MShim) for reactivity control of load changes and core depletion in conjunction with boron reactivity shim. The system is designed for several days of power operation without changing the reactor coolant system boron concentration. This along with an advanced reactor coolant pump design allows for a chemistry and volume control system that is much simplified from present PWRs. Furthermore, the nuclear renaissance provides the opportunity for the application of innovative technology in the establishment of behaviors in the operation of the reactor instead of modifying already learned and established practices. The presentation of reactor peaking factor limits, limit monitoring, nuclear data and reactor operations predictive capabilities to the control room will reflect the advanced core, new operating strategy and the opportunity of the AP1000. The proven BEACON{sup TM} core monitoring and analysis system will be used in the AP1000. BEACON is presently implemented in over 60 PWRs of different vendor origin on five continents. It is licensed by the regulatory agencies of several countries to provide surveillance of core thermal margins. In addition it provides accurate reactor operations predictions for evolutions like start-up and load changes. The AP1000 implementation of BEACON will build on this extensive experience. From vanadium fixed in-core detector signals and other online plant data, BEACON will continuously update a core model implemented with an advanced 3D nodal code. From this core model, BEACON will measure reactor power distribution, reactivity and shutdown margin and provide information to control room display and alarm presentation systems on margin to thermal and shutdown reactivity limits. Specifically, BEACON will

  12. High-temperature stability of yttria-stabilized zirconia thermal barrier ...

    Indian Academy of Sciences (India)

    bustor and vehicle acreage applications [19–21]. However, silicide coatings are generally used for oxidation ... Since, Nb alloys are being used for these applications, TBC with a prior bond coat is essential for better ..... ing; notwithstanding the bond coat mitigates the thermal mis- match between the metal substrate and YSZ ...

  13. Westinghouse corporate development of a decision software program for Radiological Evaluation Decision Input (REDI)

    Energy Technology Data Exchange (ETDEWEB)

    Bush, T.S. [Westinghosue Idaho Nuclear Co., Inc., Idaho Falls, ID (United States)

    1995-03-01

    In December 1992, the Department of Energy (DOE) implemented the DOE Radiological Control Manual (RCM). Westinghouse Idaho Nuclear Company, Inc. (WINCO) submitted an implementation plan showing how compliance with the manual would be achieved. This implementation plan was approved by DOE in November 1992. Although WINCO had already been working under a similar Westinghouse RCM, the DOE RCM brought some new and challenging requirements. One such requirement was that of having procedure writers and job planners create the radiological input in work control procedures. Until this time, that information was being provided by radiological engineering or a radiation safety representative. As a result of this requirement, Westinghouse developed the Radiological Evaluation Decision Input (REDI) program.

  14. Mechanisms Underpinning Degradation of Protective Oxides and Thermal Barrier Coatings in High Hydrogen Content (HHC) - Fueled Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Mumm, Daniel

    2013-08-31

    The overarching goal of this research program has been to evaluate the potential impacts of coal-derived syngas and high-hydrogen content fuels on the degradation of turbine hot-section components through attack of protective oxides and thermal barrier coatings. The primary focus of this research program has been to explore mechanisms underpinning the observed degradation processes, and connections to the combustion environments and characteristic non-combustible constituents. Based on the mechanistic understanding of how these emerging fuel streams affect materials degradation, the ultimate goal of the program is to advance the goals of the Advanced Turbine Program by developing materials design protocols leading to turbine hot-section components with improved resistance to service lifetime degradation under advanced fuels exposures. This research program has been focused on studying how: (1) differing combustion environments – relative to traditional natural gas fired systems – affect both the growth rate of thermally grown oxide (TGO) layers and the stability of these oxides and of protective thermal barrier coatings (TBCs); and (2) how low levels of fuel impurities and characteristic non-combustibles interact with surface oxides, for instance through the development of molten deposits that lead to hot corrosion of protective TBC coatings. The overall program has been comprised of six inter-related themes, each comprising a research thrust over the program period, including: (i) evaluating the role of syngas and high hydrogen content (HHC) combustion environments in modifying component surface temperatures, heat transfer to the TBC coatings, and thermal gradients within these coatings; (ii) understanding the instability of TBC coatings in the syngas and high hydrogen environment with regards to decomposition, phase changes and sintering; (iii) characterizing ash deposition, molten phase development and infiltration, and associated corrosive

  15. 1992 Environmental Summer Science Camp Program evaluation. The International Environmental Institute of Westinghouse Hanford Company

    Energy Technology Data Exchange (ETDEWEB)

    1993-07-01

    This report describes the 1992 Westinghouse Hanford Company/US Department of Energy Environmental Summer Science Camp. The objective of the ``camp`` was to motivate sixth and seventh graders to pursue studies in math, science, and the environment. This objective was accomplished through hands-on fun activities while studying the present and future challenges facing our environment. The camp was funded through Technical Task Plan, 424203, from the US Department of Energy-Headquarters, Office of Environmental Restoration and Waste Management, Technology Development,to Westinghouse Hanford Company`s International Environmental Institute, Education and Internship Performance Group.

  16. Thermal stability of tungsten-boron-nitride thin film as diffusion barrier

    CERN Document Server

    Park, Y K; Kim, Y T; Lee, C W

    2000-01-01

    The electrical and the structural properties of tungsten boron nitride (W-B-N) thin films were studied to investigate the effects of boron and nitrogen in the 10000 A W-B-N diffusion barrier. The W-B-N thin films were deposited by using the RF magnetron sputtering method. The impurities provided a stuffing effect that was very effective for preventing interdiffusion between the interconnection metal and the silicon during the subsequent high-temperature annealing process. The resistivities of the W-B-N thin films were in the range of 140 - 406 mu OMEGA-cm, depending on the partial pressure ratio of the N sub 2 gas and the RF power density of the W sub 2 B sub 5 target. XRD and electrical property analyses showed that the W-B-N barrier did not react with Si during the annealing in N sub 2 gas ambient, even for annealing at 1000 .deg. C for 30 min.

  17. Non-thermal dielectric-barrier discharge plasma damages human keratinocytes by inducing oxidative stress

    Science.gov (United States)

    KIM, KI CHEON; PIAO, MEI JING; HEWAGE, SUSARA RUWAN KUMARA MADDUMA; HAN, XIA; KANG, KYOUNG AH; JO, JIN OH; MOK, YOUNG SUN; SHIN, JENNIFER H.; PARK, YEUNSOO; YOO, SUK JAE; HYUN, JIN WON

    2016-01-01

    The aim of this study was to identify the mechanisms through which dielectric-barrier discharge plasma damages human keratinocytes (HaCaT cells) through the induction of oxidative stress. For this purpose, the cells were exposed to surface dielectric-barrier discharge plasma in 70% oxygen and 30% argon. We noted that cell viability was decreased following exposure of the cells to plasma in a time-dependent manner, as shown by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The levels of intracellular reactive oxygen species (ROS) were determined using 2′,7′-dichlorodihydro-fluorescein diacetate and dihydroethidium was used to monitor superoxide anion production. Plasma induced the generation of ROS, including superoxide anions, hydrogen peroxide and hydroxyl radicals. N-acetyl cysteine, which is an antioxidant, prevented the decrease in cell viability caused by exposure to plasma. ROS generated by exposure to plasma resulted in damage to various cellular components, including lipid membrane peroxidation, DNA breaks and protein carbonylation, which was detected by measuring the levels of 8-isoprostane and diphenyl-1-pyrenylphosphine assay, comet assay and protein carbonyl formation. These results suggest that plasma exerts cytotoxic effects by causing oxidative stress-induced damage to cellular components. PMID:26573561

  18. DEGRADATION OF SM2ZR2O7 THERMAL BARRIER COATING CAUSED BY CALCIUM-MAGNESIUM-ALUMINUM-SILICON OXIDE (CMAS) DEPOSITION

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Honglong; Sheng, Zhizhi; Tarwater, Emily; Zhang, Xingxing; Dasgupta, Sudip; Fergus, Jeffrey

    2015-03-16

    Rare earth zirconates are promising materials for use as thermal barrier coatings in gas turbine engines. Among the lanthanide zirconate materials, Sm2Zr2O7 with the pyrochlore structure has lower thermal conductivity and better corrosion resistance against calcium-magnesium-aluminum-silicon oxide (CMAS). In this work, after reaction with CMAS, the pyrochlore structure transforms to the cubic fluorite structure and Ca2Sm8(SiO4)6O2 forms in elongated grain.

  19. Analysis of the energetic/environmental performances of gas turbine plant: Effect of thermal barrier coatings and mass of cooling air

    Directory of Open Access Journals (Sweden)

    Ion Ion V.

    2009-01-01

    Full Text Available Zirconia stabilized with 8 wt.% Y2O3 is the most common material to be applied in thermal barrier coatings owing to its excellent properties: low thermal conductivity, high toughness and thermal expansion coefficient as ceramic material. Calculation has been made to evaluate the gains of thermal barrier coatings applied on gas turbine blades. The study considers a top ceramic coating Zirconia stabilized with 8 wt.% Y2O3 on a NiCoCrAlY bond coat and Inconel 738LC as substrate. For different thickness and different cooling air flow rates, a thermodynamic analysis has been performed and pollutants emissions (CO, NOx have been estimated to analyze the effect of rising the gas inlet temperature. The effect of thickness and thermal conductivity of top coating and the mass flow rate of cooling air have been analyzed. The model for heat transfer analysis gives the temperature reduction through the wall blade for the considered conditions and the results presented in this contribution are restricted to a two considered limits: (1 maximum allowable temperature for top layer (1200ºC and (2 for blade material (1000ºC. The model can be used to analyze other materials that support higher temperatures helping in the development of new materials for thermal barrier coatings.

  20. Moisture-Induced Delamination Video of an Oxidized Thermal Barrier Coating

    Science.gov (United States)

    Smialek, James L.; Zhu, Dongming; Cuy, Michael D.

    2008-01-01

    PVD TBC coatings were thermally cycled to near-failure at 1150 C. Normal failure occurred after 200 to 300 1-hr cycles with only moderate weight gains (0.5 mg/sq cm). Delamination and buckling was often delayed until well after cooldown (desktop spallation), but could be instantly induced by the application of water drops, as shown in a video clip which can be viewed by clicking on figure 2 of this report. Moisture therefore plays a primary role in delayed desktop TBC failure. Hydrogen embrittlement is proposed as the underlying mechanism.

  1. Emission reduction in SI engine using ethanol – gasoline blends on thermal barrier coated pistons

    OpenAIRE

    C.Ananda Srinivasan and C.G.Saravanan

    2010-01-01

    In this study, the effects of ethanol and unleaded gasoline with Isoheptanol blends on multi- cylinder SI engine were investigated. The test fuels were prepared using 99.9% pure ethanol and unleaded gasoline with Isoheptanol blend, in the ratio of E 60 + 2.0 Isoheptanol, E 50 + 1.0 Isoheptanol. In this work the performance, emission and combustion tests were conducted in multi-cylinder petrol engine. The experimental results reveal an increase in brake thermal efficiency on the use of test fu...

  2. Development and evaluation of aerogel-filled BMI sandwich panels for thermal barrier applications

    Directory of Open Access Journals (Sweden)

    A. Dineshkumar

    2016-07-01

    Full Text Available This study details a fabrication methodology envisaged to manufacture Glass/BMI honeycomb core aerogel-filled sandwich panels. Silica aerogel granules are used as core fillers to provide thermal insulation properties with little weight increase. Experimental heat transfer studies are conducted on these panels to study the temperature distribution between their two surfaces. Numerical studies are also carried out to validate the results. Despite exhibiting good thermal shielding capabilities, the Glass/BMI sandwich panels are found to oxidise at 180 ºC if exposed directly to heat. In order to increase the temperature bearing capacity and the operating temperature range for these panels, a way of coating them from outside with high temperature spray paint was tried. With a silicone-based coating, the temperature sustainability of these sandwich panels is found to increase to 350 ºC. This proved the effectiveness of the formed manufacturing process, selected high temperature coating, the coating method as well as the envisaged sandwich panel concept.

  3. Durability and Design Issues of Thermal/environmental Barrier Coatings on Sic/sic Ceramic Matrix Composites Under 1650 C Test Conditions

    Science.gov (United States)

    Zhu, Dong-Ming; Choi, Sung R.; Ghosn, Louis J.; Miller, Robert A.

    2004-01-01

    Ceramic thermal/environmental barrier coatings for SiC-based ceramics will play an increasingly important role in future gas turbine engines because of their ability to effectively protect the engine components and further raise engine temperatures. However, the coating durability remains a major concern with the ever-increasing temperature requirements. Currently, advanced T/EBC systems, which typically include a high temperature capable zirconia- (or hahia-) based oxide top coat (thermal barrier) on a less temperature capable mullite/barium-strontium-aluminosilicate (BSAS)/Si inner coat (environmental barrier), are being developed and tested for higher temperature capability Sic combustor applications. In this paper, durability of several thermal/environmental barrier coating systems on SiC/SiC ceramic matrix composites was investigated under laser simulated engine thermal gradient cyclic, and 1650 C (3000 F) test conditions. The coating cracking and delamination processes were monitored and evaluated. The effects of temperature gradients and coating configurations on the ceramic coating crack initiation and propagation were analyzed using finite element analysis (FEA) models based on the observed failure mechanisms, in conjunction with mechanical testing results. The environmental effects on the coating durability will be discussed. The coating design approach will also be presented.

  4. Troubleshooting of an Electromechanical System (Westinghouse PLC Controlling a Pneumatic Robot). High-Technology Training Module.

    Science.gov (United States)

    Tucker, James D.

    This training module on the troubleshooting of an electromechanical system, The Westinghouse Programmable Logic Controller (PLC) controlling a pneumatic robot, is used for a troubleshooting unit in an electromechanical systems/robotics and automation systems course. In this unit, students locate and repair a defect in a PLC-operated machine. The…

  5. 76 FR 73720 - Knowledge and Abilities Catalog for Nuclear Power Plant Operators: Westinghouse AP1000...

    Science.gov (United States)

    2011-11-29

    ... COMMISSION Knowledge and Abilities Catalog for Nuclear Power Plant Operators: Westinghouse AP1000 Pressurized..., NUREG-2103, Revision 0, ``Knowledge and Abilities Catalog for Nuclear Power Plant Operators... at the NRC are available online in the NRC Library at http://www.nrc.gov/reading-rm/adams.html . From...

  6. Westinghouse Hanford Company (WHC) standards/requirements identification document (S/RID)

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, G.L.

    1996-03-15

    This Standards/Requirements Identification Document (S/RID) set forth the Environmental Safety and Health (ES&H) standards/requirements for Westinghouse Hanford Company Level Programs, where implementation and compliance is the responsibility of these organizations. These standards/requirements are adequate to ensure the protection of the health and safety of workers, the public, and the environment.

  7. Microstructure and creep behaviour of plasma sprayed yttria stabilized zirconia thermal barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Soltani, R.; Coyle, T.W.; Mostaghimi [Toronto Univ., ON (Canada)

    2008-07-01

    The purpose of this study was to determine the creep/sintering characteristics of thermally sprayed zirconia coatings and attempt to understand the influence of microstructure on the creep resistance of deposits. The major modification, compared with more typical practice, was employment of powder feedstock with agglomerated sub-micron size particles (Nanox), which is compared to one of the best commercially available powders (HOSP). Thick plasma sprayed coatings were prepared and their physical and mechanical properties were characterized. Creep/sintering experiments were then conducted to investigate the response of the materials when exposed to high temperatures under load. The results showed that it could be possible to correlate the splat thickness to the creep behaviour of the coatings. (orig.)

  8. Application of thermal barrier coating for improving the suitability of Annona biodiesel in a diesel engine

    Directory of Open Access Journals (Sweden)

    Ramalingam Senthil

    2016-01-01

    Full Text Available The Annona biodiesel was produced from Annona oil through transesterification process. The aim of the present study is to analyze the performance and emission characteristics of a single cylinder, direct injection, compression ignition engine using a annona methyl ester as a fuel. They are blended together with the Neat diesel fuel such as 20%, 40%, 60%, 80%, and Neat biodiesel. The performance, emission and combustion characteristics are evaluated by operating the engine at different loads. The performance parameters such as brake thermal efficiency, brake specific fuel consumption. The emission constituents such as carbon monoxide, unburned hydrocarbons, oxides of nitrogen, and smoke were recorded. Then the piston and both exhaust and intake valves of the test engine were coated with 100 µm of NiCrAl as lining layer. Later the same parts were coated with 400 µm material of coating that was the mixture of 88% of ZrO2, 4% of MgO, and 8% of Al2O3. After the engine coating process, the same fuels is tested in the engine at the same engine operation. The same performance and emission parameters were evaluated. Finally, these parameters are compared with uncoated engine in order to find out the changes in the performance and emission parameters of the coated engine. It is concluded that the coating engine resulting in better performance, especially in considerably lower brake specific fuel consumption values. The engine emissions are lowered both through coating and annona methyl ester biodiesel expect the nitrogen oxides emission.

  9. Influence of thermally oxidized vegetable oils and animal fats on intestinal barrier function and immune variables in young pigs.

    Science.gov (United States)

    Liu, P; Kerr, B J; Weber, T E; Chen, C; Johnston, L J; Shurson, G C

    2014-07-01

    To evaluate the effect of feeding thermally oxidized lipids on metabolic oxidative status, gut barrier function, and immune response of young pigs, 108 barrows (6.67 ± 0.03 kg BW) were assigned to 12 dietary treatments in a 4 × 3 factorial arrangement in addition to a corn-soybean meal control diet. Main effects were 4 lipid sources (corn oil [CN], canola oil [CA], poultry fat [PF], and tallow [TL]) and 3 oxidation levels (original lipids [OL], slow oxidation [SO] of lipids heated for 72 h at 95°C, or rapid oxidation [RO] of lipids heated for 7 h at 185°C). Pigs were provided ad libitum access to diets for 28 d followed by controlled feed intake for 10 d. After a 24-h fast on d 38, serum was collected and analyzed for α-tocopherol (α-T), thiobarbituric acid reactive substances (TBARS), endotoxin, haptoglobin, IgA, and IgG. On the same day following serum collection, lactulose and mannitol were fed and subsequently measured in the urine to evaluate gut permeability. There was a source × peroxidation interaction for serum α-T concentration where pigs fed SO or RO had decreased (P < 0.05) serum α-T concentration compared with pigs fed OL in CA and CN diets but not in pigs fed PF and TL diets. There was no source × peroxidation interaction for serum TBARS, but among all lipid sources, pigs fed SO or RO lipids had increased (P < 0.05) serum TBARS compared with pigs fed OL. In addition, pigs fed CN or CA had greater (P < 0.05) serum TBARS compared with pigs fed PF or TL diets. There were no lipid source × peroxidation level interaction or lipid source or peroxidation level effects on serum endotoxin, haptoglobin, IgA, or IgG. Pigs fed lipid supplemented diets tended to have increased serum endotoxin (P = 0.06), IgA (P = 0.10), and IgG (P = 0.09) compared with pigs fed the control diet. There were no lipid source × peroxidation level interaction or lipid source or peroxidation level effects on urinary TBARS and lactulose to mannitol ratio. Compared with pigs

  10. Effect of thermal treatment on the characteristics of iridium Schottky barrier diodes on n-Ge (1 0 0)

    Energy Technology Data Exchange (ETDEWEB)

    Chawanda, A., E-mail: albert.chawanda@up.ac.za [Department of Physics, University of Pretoria, 0002 (South Africa); Department of Physics, Midlands State University, Bag 9055, Gweru (Zimbabwe); Coelho, S.M.M.; Auret, F.D.; Mtangi, W. [Department of Physics, University of Pretoria, 0002 (South Africa); Nyamhere, C. [Department of Physics, Nelson Mandela Metropolitan University, Box 77000, Port Elizabeth 6031 (South Africa); Nel, J.M.; Diale, M. [Department of Physics, University of Pretoria, 0002 (South Africa)

    2012-02-05

    Highlights: Black-Right-Pointing-Pointer Ir/n-Ge (1 0 0) Schottky diodes were characterized using I-V, C-V and SEM techniques under various annealing conditions. Black-Right-Pointing-Pointer The variation of the electrical and structural properties can be due to effects phase transformation during annealing. Black-Right-Pointing-Pointer Thermal stability of these diodes is maintained up to 500 Degree-Sign C anneal. Black-Right-Pointing-Pointer SEM results depicts that the onset temperature for agglomeration in 20 nm Ir/n-Ge (1 0 0) system occurs between 600 and 700 Degree-Sign C. - Abstract: Iridium (Ir) Schottky barrier diodes were deposited on bulk grown (1 0 0) Sb-doped n-type germanium by using the electron beam deposition system. Electrical characterization of these contacts using current-voltage (I-V) and capacitance-voltage (C-V) measurements was performed under various annealing conditions. The variation of the electrical properties of these Schottky diodes can be attributed to combined effects of interfacial reaction and phase transformation during the annealing process. Thermal stability of the Ir/n-Ge (1 0 0) was observed up to annealing temperature of 500 Degree-Sign C. Furthermore, structural characterization of these samples was performed by using a scanning electron microscopy (SEM) at different annealing temperatures. Results have also revealed that the onset temperature for agglomeration in a 20 nm Ir/n-Ge (1 0 0) system occurs between 600 and 700 Degree-Sign C.

  11. Delamination evaluation of thermal barrier coating on turbine blade owing to isothermal degradation using ultrasonic C-scan image

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ho Girl; Kim, Hak Joon; Song, Sung Jin; Seok, Chang Sung [Dept. of Mechanical Engineering, Sungkyunkwan University, Suwon (Korea, Republic of)

    2016-10-15

    Thermal barrier coating (TBC) is an essential element consisting of a super-alloy base and ceramic coating designed to achieve long operational time under a high temperature and pressure environment. However, the top coat of TBC can be delaminated at certain temperatures with long operation time. As the delamination of TBC is directly related to the blade damage, the coupling status of the TBC should be assured for reliable operation. Conventional studies of nondestructive evaluation have been made for detecting generation of thermally grown oxide (TGO) or qualitatively evaluating delamination in TBC. In this study, the ultrasonic C-scan method was developed to obtain the damage map inside TBC by estimating the delamination in a quantitative way. All specimens were isothermally degraded at 1,100°C with different time, having different partial delamination area. To detect partial delamination in TBC, the C-scan was performed by a single transducer using pulse-echo method with normal incidence. Partial delamination coefficients of 1 mm to 6 mm were derived by the proportion of the surface reflection signal and flaw signal which were theoretical signals using Rogers-Van Buren and Kim's equations. Using the partial delamination coefficients, the partial delamination maps were obtained. Regardless of the partial delamination coefficient, partial delamination area was increased when degradation time was increased in TBC. In addition, a decrease in partial delamination area in each TBC specimen was observed when the partial delamination coefficient was increased. From the portion of the partial delamination maps, the criterion for delamination was derived.

  12. Development of a thermal fatigue test method for thermal barrier coatings by laser excitation using a laser thermal shock facility; Entwicklung eines Pruefverfahrens zur laserinduzierten thermischen Ermuedung thermischer Schutzschichten mittels einer Laser-Thermoschockpruefeinrichtung

    Energy Technology Data Exchange (ETDEWEB)

    Nies, Daniel

    2012-07-13

    The finite nature of fossil fuel supply and the growing environmental awareness become increasingly stronger motivations for the development of efficient gas turbines and jet engines for power generation or as engines for land-, sea- and water-based vehicles. One concept developed for this purpose are thermal barrier coatings, where the thermal load of components is reduced by applying a ceramic coating onto the components. In this work the possibility to use a laser thermal shock facility for thermo-cyclic testing of thermal barrier coatings is examined. A focused laser beam is used for heating the sample and a homogeneous temperature distribution on the sample surface is achieved by the used trajectory and radial adjusted laser power. The required improvements of the existing testing facility are explained, including the development of a new sample holder and of the testing and evaluation routines for the experiments. For the assessment of the initiation and evolution of damages, acoustic emission and thermographic methods are used. The possibilities and limits of these methods are assessed during the experiments. The work also includes an extensive temperature dependent characterisation of the ceramic material used for the thermal barrier coating. In this part, the measurement of the Young's modulus by a dynamic method is to be highlighted, as this is a rarely used technique. The characterisations show the expected values, except for a lower porosity as expected by the manufacturer and no significant phase changes during isothermal heat treatments. To reach sample surface temperatures above 1000 C, it is necessary to increase the absorption by an additional coating of magnetite. The temperature distribution on the surface is measured by an infrared camera, which is calibrated for this purpose. With the incorporated active air cooling of the sample backside, the temperature gradient can be controlled, but still leaves room for improvements. Already without

  13. Nano-MgO reinforced chitosan nanocomposites for high performance packaging applications with improved mechanical, thermal and barrier properties.

    Science.gov (United States)

    De Silva, R T; Mantilaka, M M M G P G; Ratnayake, S P; Amaratunga, G A J; de Silva, K M Nalin

    2017-02-10

    Chitosan nanocomposite thin films were fabricated by incorporating MgO nanoparticles to significantly improve its physical properties for potential packaging applications. A novel in-situ method was developed to synthesise spherical shaped MgO nanoparticles by heat-treating magnesium carbonate/poly(methyl methacrylate) (PMMA) composite precursor. Optimum mechanical properties of chitosan composites were yielded at 5 (w/w%) of MgO concentration, where tensile stress and elastic modulus significantly improved by 86% and 38%, respectively, compared to those of pure chitosan films. These improvements are due to the interaction of hydroxyl and amine groups of chitosan with MgO as confirmed by FTIR spectroscopy. Fracture surface morphology indicated the interplay between MgO dispersion and aggregation on the mechanical properties at different MgO concentrations. Furthermore, the chitosan/MgO nanocomposites displayed remarkable thermal stability, flame retardant properties (satisfied V0 rating according to the UL-94 standards), UV shielding and moisture barrier properties, which could certainly add value to the packaging material. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Numerical Study of the Effects of Thermal Barrier Coating and Turbulence Intensity on Cooling Performances of a Nozzle Guide Vane

    Directory of Open Access Journals (Sweden)

    Prasert Prapamonthon

    2017-03-01

    Full Text Available This work presents a numerical investigation of the combined effects of thermal barrier coating (TBC with mainstream turbulence intensity (Tu on a modified vane of the real film-cooled nozzle guide vane (NGV reported by Timko (NASA CR-168289. Using a 3D conjugate heat transfer (CHT analysis, the NGVs with and without TBC are simulated at three Tus (Tu = 3.3%, 10% and 20%. The overall cooling effectiveness, TBC effectiveness and heat transfer coefficient are analyzed and discussed. The results indicate the following three interesting phenomena: (1 TBC on the pressure side (PS is more effective than that on the suction side (SS due to a fewer number of film holes on the SS; (2 for all three Tus, the variation trends of the overall cooling effectiveness are similar, and TBC plays the positive and negative roles in heat flux at the same time, and significantly increases the overall cooling effectiveness in regions cooled ineffectively by cooling air; (3 when Tu increases, the TBC effect is more significant, for example, at the highest Tu (Tu = 20% the overall cooling effectiveness can increase as much as 24% in the film cooling ineffective regions, but near the trailing edge (TE and the exits and downstream of film holes on the SS, this phenomenon is slight.

  15. Atmospheric Pressure Non-Thermal Plasma Activation of CO2in a Packed-Bed Dielectric Barrier Discharge Reactor.

    Science.gov (United States)

    Mei, Danhua; Tu, Xin

    2017-11-17

    Direct conversion of CO 2 into CO and O 2 is performed in a packed-bed dielectric barrier discharge (DBD) non-thermal plasma reactor at low temperatures and atmospheric pressure. The maximum CO 2 conversion of 22.6 % is achieved when BaTiO 3 pellets are fully packed into the discharge gap. The introduction of γ-Al 2 O 3 or 10 wt % Ni/γ-Al 2 O 3 catalyst into the BaTiO 3 packed DBD reactor increases both CO 2 conversion and energy efficiency of the plasma process. Packing γ-Al 2 O 3 or 10 wt % Ni/γ-Al 2 O 3 upstream of the BaTiO 3 bed shows higher CO 2 conversion and energy efficiency compared with that of mid- or downstream packing modes because the reverse reaction of CO 2 conversion-the recombination of CO and O to form CO 2 -is more likely to occur in mid- and downstream modes. Compared with the γ-Al 2 O 3 support, the coupling of the DBD with the Ni catalyst shows a higher CO 2 conversion, which can be attributed to the presence of Ni active species on the catalyst surface. The argon plasma treatment of the reacted Ni catalyst provides extra evidence to confirm the role of Ni active species in the conversion of CO 2 . © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Phosphor-Doped Thermal Barrier Coatings Deposited by Air Plasma Spray for In-Depth Temperature Sensing

    Directory of Open Access Journals (Sweden)

    Di Peng

    2016-09-01

    Full Text Available Yttria-stabilized zirconia (YSZ-based thermal barrier coating (TBC has been integrated with thermographic phosphors through air plasma spray (APS for in-depth; non-contact temperature sensing. This coating consisted of a thin layer of Dy-doped YSZ (about 40 µm on the bottom and a regular YSZ layer with a thickness up to 300 µm on top. A measurement system has been established; which included a portable; low-cost diode laser (405 nm; a photo-multiplier tube (PMT and the related optics. Coating samples with different topcoat thickness were calibrated in a high-temperature furnace from room temperature to around 900 °C. The results convincingly showed that the current sensor and the measurement system was capable of in-depth temperature sensing over 800 °C with a YSZ top layer up to 300 µm. The topcoat thickness was found to have a strong effect on the luminescent signal level. Therefore; the measurement accuracy at high temperatures was reduced for samples with thick topcoats due to strong light attenuation. However; it seemed that the light transmissivity of YSZ topcoat increased with temperature; which would improve the sensor’s performance at high temperatures. The current sensor and the measurement technology have shown great potential in on-line monitoring of TBC interface temperature.

  17. Theoretical prediction of energy release rate for interface crack initiation by thermal stress in environmental barrier coatings for ceramics

    Science.gov (United States)

    Kawai, E.; Umeno, Y.

    2017-05-01

    As weight reduction of turbines for aircraft engines is demanded to improve fuel consumption and curb emission of carbon dioxide, silicon carbide (SiC) fiber reinforced SiC matrix composites (SiC/SiC) are drawing enormous attention as high-pressure turbine materials. For preventing degradation of SiC/SiC, environmental barrier coatings (EBC) for ceramics are deposited on the composites. The purpose of this study is to establish theoretical guidelines for structural design which ensures the mechanical reliability of EBC. We conducted finite element method (FEM) analysis to calculate energy release rates (ERRs) for interface crack initiation due to thermal stress in EBC consisting of Si-based bond coat, Mullite and Ytterbium (Yb)-silicate layers on a SiC/SiC substrate. In the FEM analysis, the thickness of one EBC layer was changed from 25 μm to 200 μm while the thicknesses of the other layers were fixed at 25 μm, 50 μm and 100 μm. We compared ERRs obtained by the FEM analysis and a simple theory for interface crack in a single-layered structure where ERR is estimated as nominal strain energy in the coating layers multiplied by a constant factor (independent of layer thicknesses). We found that, unlike the case of single-layered structures, the multiplication factor is no longer a constant but is determined by the combination of consisting coating layer thicknesses.

  18. Feasibility Study on Thimble Plug Removal for Westinghouse Type PWR

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang Sup; Lee, Jae Yong; Yoon, Duk Joo; Jun, Hwang Yong; Kim, Yoon Ho [Korea Electric Power Research Institute, Taejon (Korea, Republic of)

    1996-12-31

    1. Abstract of Thimble Plug Removal- Thimble Plug Removal from the core increase core bypass flow few percent and may reduce DNBR Margin 2{approx}3%. In this feasibility study, the following analyses were performed in terms of the best estimate flow, bypass flow, DNBR margin etc. 2. Area of analysis and evaluations (a). Thermal Hydraulic (b). PCWG (c). Nuclear Design (d). Rod Performance (e). mechanical Design (f). Transient Analysis (g). LOCA Analysis. 3. Evaluation of Economic and Licensing 4. Detail analysis and design were performed for Youngkwang unit 1 as a sample plant. (author). 68 refs., figs.

  19. Analysis of the performance of the Westinghouse reactor vessel level indicating system for tests at semiscale. [PWR

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, J.E.; Miller, G.N.

    1982-10-01

    The Westinghouse Reactor Vessel Level Indicating System (RVLIS), a differential pressure level measurement system, was tested at SEMISCALE. This report contains the analyses of these tests and the conclusions of these analyses. The tests performed included small break and intermediate break tests. Also, frequency response and natural circulation tests were run and analyzed. The RVLIS always indicated a level less than the two phase froth level. The RVLIS output in early small break tests indicated a level 200 cm greater than actual collapsed liquid level. This discrepancy was caused by structural differences between SEMISCALE and a Westinghouse reactor. Once modifications were made so that SEMISCALE better simulated a Westinghouse PWR, the maximum difference between RVLIS and SEMISCALE instrumentation was 30 cm or 3% which is less than the stated uncertainty of the Westinghouse RVLIS.

  20. Chemical-cleaning process evaluation: Westinghouse steam generators. Final report. [PWR

    Energy Technology Data Exchange (ETDEWEB)

    Cleary, W.F.; Gockley, G.B.

    1983-04-01

    The Steam Generator Owners Group (SGOG)/Electric Power Research Institute (EPRI) Steam Generator Secondary Side Chemical Cleaning Program, under develpment since 1978, has resulted in a generic process for the removal of accumulated corrosion products and tube deposits in the tube support plate crevices. The SGOG/EPRI Project S150-3 was established to obtain an evaluation of the generic process in regard to its applicability to Westinghouse steam generators. The results of the evaluation form the basis for recommendations for transferring the generic process to a plant specific application and identify chemical cleaning corrosion guidelines for the materials in Westinghouse Steam Generators. The results of the evaluation, recommendations for plant-specific applications and corrosion guidelines for chemical cleaning are presented in this report.

  1. Corporate science education: Westinghouse and the value of science in mid-twentieth century America.

    Science.gov (United States)

    Terzian, Sevan G; Shapiro, Leigh

    2015-02-01

    This study examines a largely neglected aspect of the history of science popularization in the United States: corporate depictions of the value of science to society. It delineates the Westinghouse Electric Corporation's portrayals of science to its shareholders, employees and consumers, and schoolchildren and educators during World War Two and the postwar era. Annual reports to shareholders, in-house news publications, publicity records, advertising campaigns, and educational pamphlets distributed to schools reveal the company's distinct, but complementary, messages for different stakeholders about the importance of science to American society. Collectively, Westinghouse encouraged these audiences to rely on scientists' expert leadership for their nation's security and material comforts. In an era of military mobilization, the company was able to claim that industry-led scientific research would fortify the nation and create unbounded prosperity. © The Author(s) 2013.

  2. Active perioperative patient warming using a self-warming blanket (BARRIER EasyWarm) is superior to passive thermal insulation: a multinational, multicenter, randomized trial.

    Science.gov (United States)

    Torossian, Alexander; Van Gerven, Elke; Geertsen, Karin; Horn, Bengt; Van de Velde, Marc; Raeder, Johan

    2016-11-01

    Incidence of inadvertent perioperative hypothermia is still high; therefore, present guidelines advocate "prewarming" for its prevention. Prewarming means preoperative patient skin warming, which minimizes redistribution hypothermia caused by induction of anesthesia. In this study, we compared the new self-warming BARRIER EasyWarm blanket with passive thermal insulation regarding mean perioperative patient core body temperature. Multinational, multicenter randomized prospective open-label controlled trial. Surgical ward, operation room, postanesthesia care unit at 4 European hospitals. A total of 246 adult patients, American Society of Anesthesiologists class I to III undergoing elective orthopedic; gynecologic; or ear, nose, and throat surgery scheduled for 30 to 120 minutes under general anesthesia. Patients received warmed hospital cotton blankets (passive thermal insulation, control group) or BARRIER EasyWarm blanket at least 30 minutes before induction of general anesthesia and throughout the perioperative period (intervention group). The primary efficacy outcome was the perioperative mean core body temperature measured by a tympanic infrared thermometer. Secondary outcomes were hypothermia incidence, change in core body temperature, length of stay in postanesthesia care unit, thermal comfort, patient satisfaction, ease of use, and adverse events related to the BARRIER EasyWarm blanket. The BARRIER EasyWarm blanket significantly improved perioperative core body temperature compared with standard hospital blankets (36.5°C, SD 0.4°C, vs 36.3, SD 0.3°C; Pthermal comfort scores, preoperatively and postoperatively. No serious adverse effects were observed in either group. Perioperative use of the new self-warming blanket improves mean perioperative core body temperature, reduces the incidence of inadvertent perioperative hypothermia, and improves patients' thermal comfort during elective adult surgery. Copyright © 2016 The Authors. Published by Elsevier Inc

  3. Determination of Scattering and Absorption Coefficients for Plasma-Sprayed Yttria-Stabilized Zirconia Thermal Barrier Coatings at Elevated Temperatures

    Science.gov (United States)

    Eldridge, Jeffrey I.; Spuckler, Charles M.; Markham, James R.

    2009-01-01

    The temperature dependence of the scattering and absorption coefficients for a set of freestanding plasma-sprayed 8 wt% yttria-stabilized zirconia (8YSZ) thermal barrier coatings (TBCs) was determined at temperatures up to 1360 C in a wavelength range from 1.2 micrometers up to the 8YSZ absorption edge. The scattering and absorption coefficients were determined by fitting the directional-hemispherical reflectance and transmittance values calculated by a four-flux Kubelka Munk method to the experimentally measured hemispherical-directional reflectance and transmittance values obtained for five 8YSZ thicknesses. The scattering coefficient exhibited a continuous decrease with increasing wavelength and showed no significant temperature dependence. The scattering is primarily attributed to the relatively temperature-insensitive refractive index mismatch between the 8YSZ and its internal voids. The absorption coefficient was very low (less than 1 per centimeter) at wavelengths between 2 micrometers and the absorption edge and showed a definite temperature dependence that consisted of a shift of the absorption edge to shorter wavelengths and an increase in the weak absorption below the absorption edge with increasing temperature. The shift in the absorption edge with temperature is attributed to strongly temperature-dependent multiphonon absorption. While TBC hemispherical transmittance beyond the absorption edge can be predicted by a simple exponential decrease with thickness, below the absorption edge, typical TBC thicknesses are well below the thickness range where a simple exponential decrease in hemispherical transmittance with TBC thickness is expected. [Correction added after online publication August 11, 2009: "edge to a shorter wavelengths" has been updated as edge to shorter wavelengths."

  4. Ti-thickness-dependent electromigration resistance for Ti/Al-Cu-Si metallization with and without barrier rapid-thermal-anneal in an ammonia ambient

    Science.gov (United States)

    Fu, Kuan Y.; Kawasaki, Hisao; Olowolafe, Johnson O.; Pyle, Ronald E.

    1993-05-01

    The electromigration resistance for Al-Cu-Si alloy over a Ti underlayer as a function of the initial Ti thickness in the range of 0 angstroms - 1000 angstroms is investigated. After the Ti deposition, test structures have been divided into groups with and without a rapid thermal anneal (RTA) in an ammonia ambient to form a TiN barrier. The electromigration resistance of these barrier metallization systems, in general, increases with the initial Ti thickness, except when the initial Ti thickness is less than 600 angstroms for the RTA TiN/Al-Cu-Si system. A model is proposed to explain this electromigration characteristic as a function of the initial Ti thickness for these barrier metallization systems, with the support of texture analysis of the Al-alloy surface and stress measurements of barrier layers using X-ray diffraction and wafer curvature. This study highlights a direction of how a Ti-based barrier metallization system should be processed in order to optimize its electromigration resistance.

  5. Evaluation of the thermal resistance of a roof-mounted multi-reflective radiant barrier for tropical and humid conditions: Experimental study from field measurements

    CERN Document Server

    Miranville, Frédéric; Guichard, Stéphane; Boyer, Harry; Praene, Jean Philippe; Bigot, Dimitri

    2012-01-01

    This paper deals with the experimental evaluation of a roof-mounted multi-reflective radiant barrier (MRRB), installed according to the state of the art, on a dedicated test cell. An existing experimental device was completed with a specific system for the regulation of the airflow rate in the upper air layer included in a typical roof from Reunion Island. Several experimental sequences were conducted to determine the thermal resistance of the roof according to several parameters and following a specific method. The mean method, well known in international standards (ISO 9869 - 1994) for the determination of the thermal resistance using dynamic data, was used. The method was implemented in a building simulation code in order to allow the determination of the thermal indicator automatically. Experimental results are proposed according to different seasonal periods and for different values of the airflow rate in the upper air layer

  6. Thermochemistry of Calcium-Magnesium-Aluminum-Silicate (CMAS) and Components of Advanced Thermal and Environmental Barrier Coating Systems

    Science.gov (United States)

    Costa, Gustavo C. C.; Acosta, Waldo A.; Zhu, Dongming; Ghoshal, Anindya

    2017-01-01

    There is increasing interest in the degradation mechanism studies of thermal and environmental barrier coatings (TEBCs) of gas turbines by molten CaO-MgO-Al(exp. 2)O(exp. 3)-SiO(exp. 2) CMAS). CMAS minerals are usually referred as silicon-containing sand dust and volcano ash materials that are carried by the intake air into gas turbines, e.g. in aircraft engines, and their deposits often react at high temperatures (greater than 1200 degrees C) with the engine turbine coating systems and components. The high temperature reactions causes degradation and accelerated failure of the static and rotating components of the turbine engines. We discuss some results of the reactions between the CMAS and Rare-Earth (RE = Y, Yb, Dy, Gd, Nd and Sm) - oxide stabilized ZrO(exp. 2) or HfO(exp. 2) systems, and the stability of the resulting oxides and silicates. Plasma sprayed hollow tube samples (outside diameter = 4.7 mm, wall thickness = 0.76 mm and = 26 mm height) were half filled with CMAS powder, wrapped and sealed with platinum foil, and heat treated at 1310 degrees C for 5h. Samples were characterized by differential scanning calorimetry (DSC), X-ray diffraction, and cross-section electron microscopy analysis and energy dispersive X-ray spectroscopy. It was found that CMAS penetrated the samples at the grain boundaries and dissolved the TEBC materials to form silicate phases containing the rare-earth elements. Furthermore, it was found that apatite crystalline phases were formed in the samples with total rare-earth content higher than 12 mol% in the reaction zone for the ZrO(exp. 2) system. In general, samples with the nominal compositions (30YSZ), HfO(exp. 2)-7Dy(exp. 2)O(exp. 2) and ZrO(exp. 2)-9.5Y(exp. 2)O(exp. 3)-2.25Gd(exp. 2)O(exp. 3)-2.25Yb(exp. 2)O(exp. 3) exhibited lower reactivity or more resistance to CMAS than the other coating compositions of this work.

  7. Electron Barrier Formation at the Organic-Back Contact Interface is the First Step in Thermal Degradation of Polymer Solar Cells

    KAUST Repository

    Sachs-Quintana, I. T.

    2014-03-24

    Long-term stability of polymer solar cells is determined by many factors, one of which is thermal stability. Although many thermal stability studies occur far beyond the operating temperature of a solar cell which is almost always less than 65 °C, thermal degradation is studied at temperatures that the solar cell would encounter in real-world operating conditions. At these temperatures, movement of the polymer and fullerenes, along with adhesion of the polymer to the back contact, creates a barrier for electron extraction. The polymer barrier can be removed and the performance can be restored by peeling off the electrode and depositing a new one. X-ray photoelectron spectroscopy measurements reveal a larger amount of polymer adhered to electrodes peeled from aged devices than electrodes peeled from fresh devices. The degradation caused by hole-transporting polymer adhering to the electrode can be suppressed by using an inverted device where instead of electrons, holes are extracted at the back metal electrode. The problem can be ultimately eliminated by choosing a polymer with a high glass transition temperature. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. A consortium approach to commercialized Westinghouse solid oxide fuel cell technology

    Science.gov (United States)

    Casanova, Allan

    Westinghouse is developing its tubular solid oxide fuel cells (SOFCs) for a variety of applications in stationary power generation markets. By pressurizing a SOFC and integrating it with a gas turbine (GT), power systems with efficiencies as high as 70-75% can be obtained. The first such system will be tested in 1998. Because of their extraordinarily high efficiency (60-70%) even in small sizes the first SOFC products to be offered are expected to be integrated SOFC/GT power systems in the 1-7 MW range, for use in the emerging distributed generation (DG) market segment. Expansion into larger sizes will follow later. Because of their modularity, environmental friendliness and expected cost effectiveness, and because of a worldwide thrust towards utility deregulation, a ready market is forecasted for baseload distributed generation. Assuming Westinghouse can complete its technology development and reach its cost targets, the integrated SOFC/GT power system is seen as a product with tremendous potential in the emerging distributed generation market. While Westinghouse has been a leader in the development of power generation technology for over a century, it does not plan to manufacture small gas turbines. However, GTs small enough to integrate with SOFCs and address the 1-7 MW market are generally available from various manufacturers. Westinghouse will need access to a new set of customers as it brings baseload plants to the present small market mix of emergency and peaking power applications. Small cogeneration applications, already strong in some parts of the world, are also gaining ground everywhere. Small GT manufacturers already serve this market, and alliances and partnerships can enhance SOFC commercialization. Utilities also serve the DG market, especially those that have set up energy service companies and seek to grow beyond the legal and geographical confines of their current regulated business. Because fuel cells in general are a new product, because small

  9. Temperature Mapping of Air Film-Cooled Thermal Barrier Coated Surfaces Using Cr-Doped GdAlO3 Phosphor Thermography

    Science.gov (United States)

    Eldridge, Jeffrey I.; Shyam, Vikram; Wroblewski, Adam C.; Zhu, Dongming; Cuy, Michael D.; Wolfe, Douglas E.

    2016-01-01

    It has been recently shown that the high luminescence intensity from a Cr-doped GdAlO3 (Cr:GdAlO3) thermographic phosphor enables non-rastered full-field temperature mapping of thermal barrier coating (TBC) surfaces to temperatures above 1000C. In this presentation, temperature mapping by Cr:GdAlO3 based phosphor thermometry of air film-cooled TBC-coated surfaces is demonstrated for both scaled-up cooling hole geometries as well as for actual components in a burner rig test environment. The effects of thermal background radiation and flame chemiluminescence on the measurements are investigated, and advantages of this method over infrared thermography as well as the limitations of this method for studying air film cooling are discussed.

  10. Effects of RCP trip when recovering HPSI during LOCA in a Westinghouse PWR

    Energy Technology Data Exchange (ETDEWEB)

    Montero-Mayorga, Javier, E-mail: fj.montero@alumnos.upm.es; Queral, César; Rivas-Lewicky, Julio; González-Cadelo, Juan

    2014-12-15

    Highlights: • If HPSI is recovered during SBLOCA and RCPs are tripped core damage can be reached. • If the RCPs are tripped once the accumulators have injected the damage can be avoided. • If only 2 out of 3 RCPs are tripped the damage can be also avoided. • Improvements are proposed to the EOPs in order to avoid possible damage. - Abstract: Current Westinghouse Emergency Operating Procedures (EOPs) indicate initially that the operator must keep the reactor coolant pumps (RCPs) running during a Small Break Loss of Coolant Accident (SBLOCA) if there is unavailability of high pressure safety injection (HPSI) system in order to cool the core by forced convection. However, the crew must follow different EOPs along the transient depending on its evolution. In these EOPs there are several conditions which indicate the necessity of tripping one or more RCPs when HPSI is recovered. In this paper the occurrence of a SBLOCA with unavailability of HPSI has been analyzed with a model of Almaraz Nuclear Power Plant (Westinghouse 3 Loop) for TRACE code V5.0 patch 1. Two different approaches have been considered: the first one, taking into account Optimal Recovery Guidelines (ORGs) and in the second approach, the transition to Function Restoration Guidelines (FRGs) due to inadequate core cooling (ICC) conditions is considered. Results of this paper lead to the implementation of an improvement in current EOPs regarding how many RCPs should be tripped during SBLOCA sequences.

  11. Standard technical specifications, Westinghouse Plants: Bases (Sections 2.0--3.3). Volume 2, Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-04-01

    This NUREG contains the improved Standard Technical Specifications (STS) for Westinghouse plants. Revision 1 incorporates the cumulative changes to Revision 0, which was published in September 1992. The changes reflected in Revision 1 resulted from the experience gained from license amendment applications to convert to these improved STS or to adopt partial improvements to existing technical specifications. This NUREG is the result of extensive public technical meetings and discussions between the Nuclear Regulatory Commission (NRC) staff and various nuclear power plant licensees, Nuclear Steam Supply System (NSSS) Owners Groups, specifically the Westinghouse Owners Group (WOG), NSSS vendors, and the Nuclear Energy Institute (NEI). The improved STS were developed based on the criteria in the Final Commission Policy Statement on Technical Specifications Improvements for Nuclear Power Reactors, dated July 22, 1993 (58 FR 39132). Licensees are encouraged to upgrade their technical specifications consistent with those criteria and conforming, to the extent practical and consistent with the licensing basis for the facility, to Revision 1 to the improved STS. The Commission continues to place the highest priority on requests for complete conversions to the improved STS. Licensees adopting portions of the improved STS to existing technical specifications should adopt all related requirements, as applicable, to achieve a high degree of standardization and consistency.

  12. Sensitivity Analysis of Onsite Atmospheric Dispersion Factor in Westinghouse type NPP in KOREA

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Chan; Yoon, Duk Joo; Song, Dong Soo [KHNP CRI, Daejeon (Korea, Republic of)

    2016-10-15

    ARCON96 is a NRC licensed air dispersion model to evaluate onsite atmospheric relative concentration X/Q. The purpose of this paper is to provide some results for checking and testing the functionalities of ARCON96. Specially, this code is optimized to estimate a habitability of control room. Since NUREG 0737 issue, the control room habitability has been studied for a FSAR (Final Safety Analysis Report). Some assumptions and methodology is used in this paper. Some methodology is introduced in this paper. The reason of the selection of 2-loop Westinghouse NPP is because of carrying out the study project for the 2-loop Westinghouse NPP in the condition of the defueled NPP condition. Onsite atmospheric dispersion factor sensitivity is performed. Key impact factor is reviewed. Some results are below: a. Time averaged effect of X/Q is timely increased. b. ARCON96 code is more conservative at the low wind speed conditions. c. Building wake impact is significant in the condition of unstable atmospheric class with more than 7m/sec of wind speed. d. Plume meander effect is strong when the distance from the release point is small. e. The other plume meander effect is strong when the meander duration time is accumulated Finally, these results show that the appropriate conservation of ARCON96 is appeared in some conditions. Also these results seem to be in good agreement with NRC Regulatory Guide and positions.

  13. Simulation of thermal stress in Er2O3 and Al2O3 tritium penetration barriers by finite-element analysis

    Science.gov (United States)

    Liu, Ze; Wang, Yuan; Yu, Guogang; He, Anping; Wang, Ling

    2017-09-01

    The physical vapor deposition method is an effective way to deposit Al2O3 and Er2O3 on 316L stainless steel substrates acting as tritium permeation barriers in a fusion reactor. The distribution of residual thermal stress is calculated both in Al2O3 and Er2O3 coating systems with planar and rough substrates using finite element analysis. The parameters influencing the thermal stress in the sputter process are analyzed, such as coating and substrate properties, temperature and Young’s modulus. This work shows that the thermal stress in Al2O3 and Er2O3 coating systems exhibit a linear relationship with substrate thickness, temperature and Young’s modulus. However, this relationship is inversed with coating thickness. In addition, the rough substrate surface can increase the thermal stress in the process of coating deposition. The adhesive strength between the coating and the substrate is evaluated by the shear stress. Due to the higher compressive shear stress, the Al2O3 coating has a better adhesive strength with a 316L stainless steel substrate than the Er2O3 coating. Furthermore, the analysis shows that it is a useful way to improve adhesive strength with increasing interface roughness.

  14. Effect of Gd2O3 on the microstructure and thermal properties of nanostructured thermal barrier coatings fabricated by air plasma spraying

    Directory of Open Access Journals (Sweden)

    Yixiong Wang

    2016-08-01

    Full Text Available The nanostructured 4–8 mol% Gd2O3−4.5 mol% Y2O3-ZrO2 (4–8 mol% GdYSZ coatings were developed by the atmospheric plasma spraying technique. The microstructure and thermal properties of plasma-sprayed 4–8 mol% GdYSZ coatings were investigated. The experimental results indicate that typical microstructure of the as-sprayed coatings were consisted of melted zones, nano-zones, splats, nano-pores, high-volume spheroidal pores and micro-cracks. The porosity of the 4, 6 and 8 mol% GdYSZ coatings was about 9.3%, 11.7% and 13.3%, respectively. It was observed that the addition of gadolinia to the nano-YSZ could significantly reduce the thermal conductivity of nano-YSZ. The thermal conductivity of GdYSZ decreased with increasing Gd2O3 addition. And the reduction in thermal conductivity is mainly attributed to the addition of Gd2O3, which results in the increase in oxygen vacancies, lattice distortion and porosity.

  15. Thermal Fatigue Testing of ZrO2-Y2O3 Thermal Barrier Coating Systems using a High Power CO2 Laser

    Science.gov (United States)

    Zhu, Dongming; Miller, Robert A.

    1997-01-01

    In the present study, the mechanisms of fatigue crack initiation and propagation, and of coating failure, under thermal loads that simulate diesel engine conditions, are investigated. The surface cracks initiate early and grow continuously under thermal Low Cycle Fatigue (LCF) and High Cycle Fatigue (HCF) stresses. It is found that, in the absence of interfacial oxidation, the failure associated with LCF is closely related to coating sintering and creep at high temperatures. Significant LCF and HCF interactions have been observed in the thermal fatigue tests. The fatigue crack growth rate in the ceramic coating strongly depends on the characteristic HCF cycle number, N*(sub NCF), which is defined as the number of HCF cycles per LCF cycle. The crack growth rate is increased from 0.36 microns/LCF cycle for a pure LCF test to 2.8 microns/LCF cycle for a combined LCF and HCF test at N*(sub NCF) about 20,000. A surface wedging model has been proposed to account for the HCF crack growth in the coating systems. This mechanism predicts that HCF damage effect increases with increasing surface temperature swing, the thermal expansion coefficient and the elastic modulus of the ceramic coating, as well as with the HCF interacting depth. A good agreement has been found between the analysis and experimental evidence.

  16. Solution of closing of the columns of thermocouples in Asco reactors 1 and 2 with Cetna of Westinghouse; Solucion de cierre de las columnas de termopares en reactores Asco 1 and 2 con Cetna de Westinghouse

    Energy Technology Data Exchange (ETDEWEB)

    Sunjic, B.; Reichenbach, M.; Llibre, E.

    2014-10-01

    Occasionally, small leaks have been discovered in operating PWRs in the Thermo Couple columns Penetrations. In order to mitigate this issue, Westinghouse has designed and developed the CETNA element, which does not use cono-seals. This article shows the CETNA supply for Asco NPP to prevent potential leaks in the penetrations. (Author)

  17. Thermal barrier coating by electron beam-physical vapor deposition of zirconia co-doped with yttria and niobia

    Directory of Open Access Journals (Sweden)

    Daniel Soares de Almeida

    2010-08-01

    Full Text Available The most usual ceramic material for coating turbine blades is yttria doped zirconia. Addition of niobia, as a co-dopant in the Y2O3-ZrO2 system, can reduce the thermal conductivity and improve mechanical properties of the coating. The purpose of this work was to evaluate the influence of the addition of niobia on the microstructure and thermal properties of the ceramic coatings. SEM on coatings fractured cross-section shows a columnar structure and the results of XRD show only zirconia tetragonal phase in the ceramic coating for the chemical composition range studied. As the difference NbO2,5-YO1,5 mol percent increases, the tetragonality increases. A significant reduction of the thermal conductivity, measured by laser flash technique in the zirconia coating co-doped with yttria and niobia when compared with zirconia-yttria coating was observed.

  18. "A Highly Selected Strain of Guinea Pigs": The Westinghouse Science Talent Search and Educational Meritocracy, 1942-1958

    Science.gov (United States)

    Terzian, Sevan G.; Rury, John L.

    2014-01-01

    Overview: This article examines the Westinghouse Science Talent Search over the first sixteen years of its operation. A national contest involving thousands of high school seniors annually, it reflected a growing national concern with developing scientific manpower in the midst of global conflict, the Cold War, and a growing military-industrial…

  19. Mechanical properties of EB-PVD ZrO{sub 2} thermal barrier coatings; Mechanische Eigenschaften von EB-PVD ZrO{sub 2} Waermedaemmschichten

    Energy Technology Data Exchange (ETDEWEB)

    Held, Carolin

    2014-08-29

    In this work, the elastic properties of thermal barrier coatings which were produced by electron-beam enhanced physical vapour deposition were investigated, as well as the dependency of the properties on the sample microstructure, the thermal treatment and the test method. For this purpose, not only commercial coatings were characterized, but also special sample material was used which consists of a 1 mm thick layer of EB-PVD TBC. This material was isothermally heat treated for different times at 950 C, 1100 C and 1200 C and then tested in a specially developed miniaturized bend test and by dynamic mechanical analysis. The sample material was tested by nanoindentation in order to measure the Young's modulus on a local scale, and the porosity of the samples was determined by microstructure analysis and porosimetry. The decrease of porosity could be connected with sintering and subsequent stiffening of the material. The test results are dependent on the tested volume. A small test volume leads to larger measured Young's moduli, while a large test volume yields lower values. The test volume also has an influence on the increase of stiffness during thermal exposure. With a small tested volume, a quicker increase of the Young's modulus was registered, which could be associated to the sintering of local structures.

  20. Westinghouse Hanford Company operational environmental monitoring annual report, calendar year 1994

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, J.; Fassett, J.W.; Johnson, A.R.; Johnson, V.G.; Markes, B.M.; McKinney, S.M.; Moss, K.J.; Perkins, C.J.; Richterich, L.R.

    1995-08-01

    This document presents the results of the Westinghouse Hanford Company near-facility operational environmental monitoring for 1994 in the 100, 200/600, and 300/400 Areas of the Hanford Site, in south-central Washington State. Surveillance activities included sampling and analyses of ambient air surface water, groundwater, soil, sediments, and biota. Also, external radiation measurements and radiological surveys were taken at waste disposal sites, radiologically controlled areas, and roads. These activities were conducted to assess and control the effects of nuclear facilities and waste sites on the local environment. In addition, diffuse sources were monitored to determine compliance with Federal, State, and/or local regulations. In general, although effects from nuclear facilities are still seen on the Hanford Site and radiation levels are slightly elevated when compared to offsite locations, the differences are less than in previous years.

  1. Demonstration of retrieval methods for Westinghouse Hanford Corporation October 20, 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-10-01

    Westinghouse Hanford Corporation has been pursuing strategies to break up and retrieve the radioactive waste material in single shell storage tanks at the Hanford Nuclear Reservation, by working with non-radioactive ``saltcake`` and sludge material that simulate the actual waste. It has been suggested that the use of higher volumes of water than used in the past (10 gpm nozzles at 10,000 psi) might be successful in breaking down the hard waste simulants. Additionally, the application of these higher volumes of water might successfully be applied through commercially available tooling using methods similar to those used in the deslagging of large utility boilers. NMW Industrial Services, Inc., has proposed a trial consisting of three approaches each to dislodging both the solid (saltcake) simulant and the sludge simulant.

  2. Westinghouse Hanford Company operational environmental monitoring annual report - calendar year 1995

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, J.W., Westinghouse Hanford

    1996-07-30

    This document summarizes the results of the Westinghouse Hanford Company (WHC) near-facility operational environmental monitoring for 1995 in the 100, 200/600, and 300/400 Areas of the Hanford Site, in south-central Washington State. Surveillance activities included sampling and analyses of ambient air, surface water,groundwater, soil, sediments, and biota. Also, external radiation measurements and radiological surveys were taken at waste disposal sites, radiologically controlled areas, and roads. These activities were conducted to assess and control the effects of nuclear facilities and waste sites on the local environment. In addition, diffuse sources were monitored to determine compliance with Federal, State, and/or local regulations. In general, although effects from nuclear facilities can still be observed on the Hanford Site and radiation levels are slightly elevated when compared to offsite locations, the differences are less than in previous years.

  3. Radon, helium and uranium survey in some thermal springs located in NW Himalayas, India: mobilization by tectonic features or by geochemical barriers?

    Science.gov (United States)

    Walia, V; Quattrocchi, F; Virk, H S; Yang, T F; Pizzino, L; Bajwa, B S

    2005-09-01

    Radon, helium and uranium measurements have been carried out in hot water springs in the Parbati and Beas valleys of Himachal Himalaya. Most of these hot springs are known as famous pilgrimage centers. The activity of dissolved radon in the liquid phase is found to vary widely, by an order of magnitude, between 10 and 750 Bq L(-1), whereas, the dissolved helium content in these thermal springs varies between 10 and 100 ppm. The uranium contents are low and vary from geochemical barriers cause the mobilization of uranile ions in solution (UO2+); the most plausible hypothesis is when the conditions are oxidising, confirming the importance of physico-chemical conditions up to the supergenic environment, to control the fluid geochemistry of the U-He-222Rn system. Some evidence is available from both geothermometric considerations and geochemical data which will be reported elsewhere, whereas the present study is focused on U decay series-noble gas geochemistry. The first analysis of collected 3He/4He data is consistent with a crustal signature at the studied thermal springs.

  4. Effects of Laser Remelting and Oxidation on NiCrAlY/8Y2O3-ZrO2 Thermal Barrier Coatings

    Science.gov (United States)

    Xu, S. Q.; Zhu, C.; Zhang, Y.

    2017-12-01

    In this study, three groups of thermal barrier coatings (TBCs) samples were remelted by CO2 laser with different laser energy densities (1, 5 and 10 J/mm2) to seal the surface of yttria-stabilized zirconia (YSZ) coatings. Microscopic observations showed that the cracks size and the remelted depth in YSZ coatings increased. A 50-μm-thick dense layer was formed on the surface of YSZ coating in samples with 1 J/mm2 energy density. Microindentation tests showed that the Vickers hardness of YSZ coatings increases with the increase in laser energy density. After isothermal oxidation at 1200 °C for 200 h, thinner thermally growth oxides were found in laser remelted YSZ samples under energy density of 1 J/mm2 (6.32 ± 0.28 μm). Cyclic oxidation results showed that the weight gain per unit area of low energy density laser remelted TBCs was smaller than that of the high energy density laser remelted and as-sprayed TBCs.

  5. Effect of Plasticizer Type and Concentration on Tensile, Thermal and Barrier Properties of Biodegradable Films Based on Sugar Palm (Arenga pinnata Starch

    Directory of Open Access Journals (Sweden)

    Muhammed L. Sanyang

    2015-06-01

    Full Text Available The use of starch based films as a potential alternative choice to petroleum derived plastics is imperative for environmental waste management. This study presents a new biopolymer (sugar palm starch for the preparation of biodegradable packaging films using a solution casting technique. The effect of different plasticizer types (glycerol (G, sorbitol (S and glycerol-sorbitol (GS combination with varying concentrations (0, 15, 30 and 45, w/w% on the tensile, thermal and barrier properties of sugar palm starch (SPS films was evaluated. Regardless of plasticizer types, the tensile strength of plasticized SPS films decreased, whereas their elongation at break (E% increased as the plasticizer concentrations were raised. However, the E% for G and GS-plasticized films significantly decreased at a higher plasticizer concentration (45% w/w due to the anti-plasticization effect of plasticizers. Change in plasticizer concentration showed an insignificant effect on the thermal properties of S-plasticized films. The glass transition temperature of SPS films slightly decreased as the plasticizer concentration increased from 15% to 45%. The plasticized films exhibited increased water vapor permeability values from 4.855 × 10−10 to 8.70 × 10−10 g·m−1·s−1·Pa−1, irrespective of plasticizer types. Overall, the current study manifested that plasticized sugar palm starch can be regarded as a promising biopolymer for biodegradable films.

  6. Breaking through the Solid/Liquid Processability Barrier: Thermal Conductivity and Rheology in Hybrid Graphene-Graphite Polymer Composites.

    Science.gov (United States)

    Varenik, Maxim; Nadiv, Roey; Levy, Idan; Vasilyev, Gleb; Regev, Oren

    2017-03-01

    Thermal conductivity (TC) enhancement of an insulating polymer matrix at low filler concentration is possible through the loading of a high aspect ratio, thermally conductive single filler. Unfortunately, the dispersion of high-aspect-ratio particles greatly influences the rheological behavior of the polymer host at relatively low volume fractions, which makes further polymer processing or mixing difficult. A possible remedy is using two (hybrid) fillers, differing in their aspect ratios: (1) a plate-like filler, which sharply increases both viscosity and TC, and (2) an isotropic filler, which gradually increases these properties. We examine this hypothesis in a thermosetting silicone rubber by loading it with different ratios, (1)/(2), of graphene nanoplatelets (GNPs) (1) and graphite powder (2). We constructed a "phase diagram" delineating two composite processability regions: solid-like (moldable) or fluid-like (pourable). This diagram may be employed to tailor the mixture's viscosity to a desired TC value by varying the fillers' volume fraction. The phase diagram highlights the low volume fraction value, above which the composite is solid-like (low processability) for a single high-aspect-ratio nanofiller. By using hybrid filling, one can overcome this limit and prepare a fluid-like composite at a desired TC, not accessible by the single nanofiller. Thus, it provides an indicative tool for polymer processing, especially in applications such as the encapsulation of electronic devices. This approach was demonstrated for a heat source (resistor) potted by silicon rubber graphene-graphite composites, for which a desired TC was obtained in both solid- and liquid-like regions.

  7. Design of Thermochromic Polynorbornene Bearing Spiropyran Chromophore Moieties: Synthesis, Thermal Behavior and Dielectric Barrier Discharge Plasma Treatment

    Directory of Open Access Journals (Sweden)

    Saleh A. Ahmed

    2017-11-01

    Full Text Available A new class of thermochromic polynorbornene with pendent spiropyran moieties has been synthesized. Functionalization of norbornene monomers with spirobenzopyran moieties has been achieved using Steglich esterification. These new monomeric materials were polymerized via Ring Opening Metathesis Polymerization (ROMP. In spite of their poor solubility, polynorbornenes with spirobenzopyran exhibited thermochromic behavior due to the conversion of their closed spiropyran moieties to the open merocyanine form. Moreover, these polymers displayed bathochromic shifts in their optical response, which was attributed to the J-aggregation of the attached merocyanine moieties that were associated with their high concentration in the polymeric chain. The surface of the obtained polymers was exposed to atmospheric pressure air Dielectric Barrier Discharge (DBD plasma system, which resulted in the reduction of the surface porosity and converted some surface area into completely non-porous regions. Moreover, the plasma system created some areas with highly ordered J-aggregates of the merocyanine form in thread-like structures. This modification of the polymers’ morphology may alter their applications and allow for these materials to be potential candidates for new applications, such as non-porous membranes for reverse osmosis, nanofiltration, or molecular separation in the gas phase.

  8. Radioactive waste shipments to Hanford retrievable storage from Westinghouse Advanced Reactors and Nuclear Fuels Divisions, Cheswick, Pennsylvania

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, D. [Westinghouse Hanford Co., Richland, WA (United States); Pottmeyer, J.A.; Weyns, M.I.; Dicenso, K.D.; DeLorenzo, D.S. [Los Alamos Technical Associates, Inc., NM (United States)

    1994-04-01

    During the next two decades the transuranic (TRU) waste now stored in the burial trenches and storage facilities at the Hanford Sits in southeastern Washington State is to be retrieved, processed at the Waste Receiving and Processing Facility, and shipped to the Waste Isolation Pilot Plant (WIPP), near Carlsbad, New Mexico for final disposal. Approximately 5.7 percent of the TRU waste to be retrieved for shipment to WIPP was generated by the decontamination and decommissioning (D&D) of the Westinghouse Advanced Reactors Division (WARD) and the Westinghouse Nuclear Fuels Division (WNFD) in Cheswick, Pennsylvania and shipped to the Hanford Sits for storage. This report characterizes these radioactive solid wastes using process knowledge, existing records, and oral history interviews.

  9. Resolution of the direct containment heating issue for all Westinghouse plants with large dry containments or subatmospheric containments

    Energy Technology Data Exchange (ETDEWEB)

    Pilch, M.M.; Allen, M.D.; Klamerus, E.W. [Sandia National Labs., Albuquerque, NM (United States)

    1996-03-01

    This report uses the methodology and scenarios described in NUREG/CR-6075 and NUREG/CR-6075, Supplement 1, to address the direct containment heating (DCH) issue for all Westinghouse plants with large dry or subatmospheric containments. DCH is considered resolved if the conditional containment failure probability (CCFP) is less than 0.1. The methodology calls for an initial screening phase in which the CCFP for each plant is calculated based on loads versus strength evaluations using plant-specific information. The DCH issue is considered resolved for a plant if the CCFP calculated in the screening phase is less than 0.01. This value is more stringent than the overall success criterion of 0.1. The CCFPs for all of the Westinghouse plants with dry containments were less than 0.01 in the screening phase calculations, and thus, the DCH issue is resolved for these plants based on containment loads alone. No additional analyses are required.

  10. Effect of thermally growth oxides (TGO) on adhesion strength for high purity yitria stabilised zirconia (YSZ) and rare - Earth lanthanum zirconates (LZ) multilayer thermal barrier coating before and after isothermal heat treatment

    Science.gov (United States)

    Yunus, Salmi Mohd; Johari, Azril Dahari; Husin, Shuib

    2017-12-01

    Investigation on the effect of Thermally Growth Oxides (TGO) on the adhesion strength for thermal barrier coating (TBC) was carried out. The TBC under studied was the multilayer systems which consist of NiCrAlY bond coat and YSZ/LZ ceramic coating deposited on Ni-based superalloy substrates. The development of thermally growth oxides (TGO) for both TBC systems after isothermal heat treatment was measured. Isothermal heat treatment was carried out at 1100 ˚C for 100 hours to age the samples. ASTM D4541: Standard Test Method for Pull-off Strength of Coatings using Portable Adhesion Tester was used to measure the adhesion strength of both TBC systems before and after heat treatment. The effect of the developed TGO on the measured adhesion strength was examined and correlation between them was established individually for both TBC systems. The failure mechanism of the both system was also identified; either cohesive or adhesive or the combination of both. The results showed that TGO has more than 50% from the bond coat layer for rare-earth LZ system compared to the typical YSZ system, which was less than 10 % from the bond coat layer. This leads to the lower adhesion strength of rare-earth LZ coating system compared to typical YSZ system. Failure mechanism during the pull-off test also was found to be different for both TBC systems. The typical YSZ system experienced cohesive failure whereas the rare-earth LZ system experienced the combination of cohesive and adhesive failure.

  11. Ichthyoplankton entrainment study at the SRS Savannah River water intakes for Westinghouse Savannah River Company

    Energy Technology Data Exchange (ETDEWEB)

    Paller, M. (Westinghouse Savannah River Co., Aiken, SC (United States))

    1992-03-26

    Cooling water for L and K Reactors and makeup water for Par Pond is pumped from the Savannah River at the 1G, 3G, and 5G pump houses. Ichthyoplankton (drifting fish larvae and eggs) from the river are entrained into the reactor cooling systems with the river water and passed through the reactor's heat exchangers where temperatures may reach 70[degrees]C during full power operation. Ichthyoplankton mortality under such conditions is assumed to be 100 percent. The number of ichthyoplankton entrained into the cooling system depends on a variety of variables, including time of year, density and distribution of ichthyoplankton in the river, discharge levels in the river, and the volume of water withdrawn by the pumps. Entrainment at the 1 G pump house, which is immediately downstream from the confluence of Upper Three Runs Creek and the Savannah River, is also influenced by discharge rates and ichthyoplankton densities in Upper Three Runs Creek. Because of the anticipated restart of several SRS reactors and the growing concern surrounding striped bass and American shad stocks in the Savannah River, the Department of Energy requested that the Environmental Sciences Section (ESS) of the Savannah River Laboratory sample ichthyoplankton at the SRS Savannah River intakes. Dams Moore, Inc., under a contract with Westinghouse Savannah River Company performed the sampling and data analysis for the ESS.

  12. Collections and Analyses of Common Cause Failure Data for the Korea Standard and Westinghouse Type NPPs

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Dae Il; Han, S. H

    2007-04-15

    The analyses of the CCF events for domestic NPPs were performed to establish the domestic database for the CCF events and to deliver supply them to the operation office of the international common cause failure data exchange (ICDE) project. We collected and analyzed the CCF events of emergency diesel generators, centrifugal pumps, motor-operated valves, check valves, circuit breakers for the Korean Standard Type nuclear power plants (NPPs), Yonggwang Units 3 and 4 and Ulchin Units 3 and 4, and the Westinghouse type NPPs, Kori Unit 3 and 4 and Yonggwang Units 1 and 2. First, the components to be collected and analyzed were classified into the common cause component groups (CCCGs) according to the ICDE coding guidelines. Next, the CCF events were identified based on reviews of the component database for the PSA and its related documents, and consultations with NPP staff. Fourteen CCF events were identified. The ratio of the number of CCF events to that of individual failure events was identified as approximately 10 percentages. However, an in depth review of the CCF events showed that most failure severities of them were identified as partial CCF events, which can be interpreted as some component failures within the CCCGs. Root causes of the CCF events were identified as 9 internal part failures, 2 human errors, 2 design deficiencies, 1 procedure inadequacy. It could be concluded that the major root causes of the CCF events were internal piece part failures.

  13. Power plant simulators using Westinghouse distributed processing family hardware and software

    Energy Technology Data Exchange (ETDEWEB)

    Griebenow, R.; Sudduth, A.; Heuser, S.; Perdeus, M.; Fray, R.

    1993-10-01

    Duke Power Company and the Electric Power Research Institute have embarked on a joint effort to develop plant specific engineering and training simulators to support control replacement projects in Duke's fossil plants. These simulators use low cost personal computer hardware (PCs) and modular process simulation development software, integrated to Westinghouse Distributed Processing Family (WDPF) control hardware and software, to provide an accurate representation of the plant process and controls. Integrating the PC-based process simulation to the control system proved to be a very complex task. To meet the interface requirements, firmware was modified, and software and interface cards were developed that allow high-speed parallel access to the control system processor memory. In addition, modifications had to be made to provide necessary simulator training functions such as freezing the system, saving snap-shots, and loading initial conditions. This paper provides details on the development of the PC/WDPF interface and simulator instructor capabilities. In addition, it outlines plans for use of the simulator as an operator training and controls engineering tool.

  14. Thermochemistry of CaO-MgO-Al2O3-SiO2 (CMAS) and Advanced Thermal and Environmental Barrier Coating Systems

    Science.gov (United States)

    Costa, Gustavo; Zhu, Dongming

    2017-01-01

    CaO-MgO-Al2O3-SiO2 (CMAS) oxides are constituents in a broad number of materials and minerals which have recently inferred to discussions in materials science, planetary science, geochemistry and cosmochemistry communities. In materials science, there is increasing interest in the degradation studies of thermal (TBC) and environmental (EBC) barrier coatings of gas turbines by molten CMAS. CMAS minerals usually are carried by the intake air into gas turbines, e.g. in aircraft engines, and their deposits react at high temperatures (1000C) with the coating materials. This causes degradation and accelerated failure of the static and rotating components of the turbine engines. We discuss some preliminary results of the reactions between CMAS and Rare-Earth (RE Y, Yb, Dy, Gd, Nd and Sm) oxide stabilized ZrO2 or HfO2 systems, and the stability of the resulting oxides and silicates. Plasma sprayed hollow tube samples ( 2.2 mm and 26 mm height) were half filled with CMAS powder, wrapped and sealed with platinum foil, and heat treated at 1310 C for 5h. Samples were characterized by differential scanning calorimetry, X-ray diffraction and cross section electron microscopy analysis.

  15. Real-Time Thermographic-Phosphor-Based Temperature Measurements of Thermal Barrier Coating Surfaces Subjected to a High-Velocity Combustor Burner Environment

    Science.gov (United States)

    Eldridge, Jeffrey I.; Jenkins, Thomas P.; Allison, Stephen W.; Cruzen, Scott; Condevaux, J. J.; Senk, J. R.; Paul, A. D.

    2011-01-01

    Surface temperature measurements were conducted on metallic specimens coated with an yttria-stabilized zirconia (YSZ) thermal barrier coating (TBC) with a YAG:Dy phosphor layer that were subjected to an aggressive high-velocity combustor burner environment. Luminescence-based surface temperature measurements of the same TBC system have previously been demonstrated for specimens subjected to static furnace or laser heating. Surface temperatures were determined from the decay time of the luminescence signal of the YAG:Dy phosphor layer that was excited by a pulsed laser source. However, the furnace and laser heating provides a much more benign environment than that which exists in a turbine engine, where there are additional challenges of a highly radiant background and high velocity gases. As the next step in validating the suitability of luminescence-based temperature measurements for turbine engine environments, new testing was performed where heating was provided by a high-velocity combustor burner rig at Williams International. Real-time surface temperature measurements during burner rig heating were obtained from the decay of the luminescence from the YAG:Dy surface layer. The robustness of several temperature probe designs in the sonic velocity, high radiance flame environment was evaluated. In addition, analysis was performed to show whether the luminescence decay could be satisfactorily extracted from the high radiance background.

  16. Hot corrosion behavior of nanostructured Gd2O3 doped YSZ thermal barrier coating in presence of Na2SO4 + V2O5 molten salts

    Directory of Open Access Journals (Sweden)

    Yixiong Wang

    2017-08-01

    Full Text Available Nickel-based superalloy DZ125 was first sprayed with a NiCrAlY bond coat and followed with a nanostructured 2 mol% Gd2O3−4.5 mol% Y2O3-ZrO2 (2GdYSZ topcoat using air plasma spraying (APS. Hot corrosion behavior of the as-sprayed thermal barrier coatings (TBCs were investigated in the presence of 50 wt% Na2SO4 + 50 wt% V2O5 as the corrosive molten salt at 900 °C for 100 h. The analysis results indicate that Gd doped YVO4 and m-ZrO2 crystals were formed as corrosion products due to the reaction of the corrosive salts with stabilizers (Y2O3, Gd2O3 of zirconia. Cross-section morphology shows that a thin layer called TGO was formed at the bond coat/topcoat interface. After hot corrosion test, the proportion of m-ZrO2 phase in nanostructured 2GdYSZ coating is lower than that of nano-YSZ coating. The result reveals that nanostructured 2GdYSZ coating exhibits a better hot corrosion resistance than nano-YSZ coating.

  17. A synchrotron X-ray diffraction deconvolution method for the measurement of residual stress in thermal barrier coatings as a function of depth.

    Science.gov (United States)

    Li, C; Jacques, S D M; Chen, Y; Daisenberger, D; Xiao, P; Markocsan, N; Nylen, P; Cernik, R J

    2016-12-01

    The average residual stress distribution as a function of depth in an air plasma-sprayed yttria stabilized zirconia top coat used in thermal barrier coating (TBC) systems was measured using synchrotron radiation X-ray diffraction in reflection geometry on station I15 at Diamond Light Source, UK, employing a series of incidence angles. The stress values were calculated from data deconvoluted from diffraction patterns collected at increasing depths. The stress was found to be compressive through the thickness of the TBC and a fluctuation in the trend of the stress profile was indicated in some samples. Typically this fluctuation was observed to increase from the surface to the middle of the coating, decrease a little and then increase again towards the interface. The stress at the interface region was observed to be around 300 MPa, which agrees well with the reported values. The trend of the observed residual stress was found to be related to the crack distribution in the samples, in particular a large crack propagating from the middle of the coating. The method shows promise for the development of a nondestructive test for as-manufactured samples.

  18. High Temperature Degradation of Advanced Thermal and Environmental Barrier Coatings (TEBCs) by CaO-MgO-Al2O3-SiO2 (CMAS)

    Science.gov (United States)

    Costa, Gustavo; Zhu, Dongming

    2017-01-01

    There is increasing interest in the degradation studies of thermal and environmental barrier coatings (TEBCs) of gas turbines by molten CaO-MgO-Al2O3-SiO2 (CMAS). CMAS minerals are usually referred as silica-containing sand dust and volcano ash materials that are carried by the intake air into gas turbines, e.g. aircraft engines. The low-melting deposits react at high temperatures (1000C) with the coating materials. This causes degradation and accelerated coating failure of the static and rotating components of the turbine engines. We discuss some preliminary results of the reactions between CMAS and Rare-Earth (RE Y, Yb, Dy, Gd, Nd and Sm) oxide stabilized ZrO2 or HfO2 systems, and the stability of the resulting oxides and silicates. Plasma sprayed hollow tube samples (outer diameter 4.7 mm, wall thickness 0.76 mm and 26 mm height) were half filled with CMAS powder, wrapped and sealed with platinum foil, and heat- treated at 1310 C for 5h. Samples were characterized by differential scanning calorimetry, X-ray diffraction and cross section electron microscopy analysis.

  19. Animal intrusion studies for protective barriers: Status report for FY 1988

    Energy Technology Data Exchange (ETDEWEB)

    Cadwell, L.L.; Eberhardt, L.E.; Simmons, M.A.

    1989-05-01

    The objective of the Biointrusion Control Task is to provide technical support to Westinghouse Hanford Company's Protective Barrier Development Program for evaluating and predicting potential impacts of animal burrowing on long-term barrier performance. This document reviews the major accomplishments for FY 1988, which is the initial year of the work. The scope of work includes a literature review, field studies, and modeling to assess burrowing impacts as they may contribute to increased infiltration of surface water through barriers, increased quantities of soil available for erosion because of surface soil disturbance, and direct physical transport of contaminants to the surface. 68 refs., 8 figs., 5 tabs.

  20. Model assessment of protective barriers: Part 3

    Energy Technology Data Exchange (ETDEWEB)

    Fayer, M.J.; Rockhold, M.L.; Holford, D.J.

    1992-02-01

    Radioactive waste exists at the US Department of Energy's (DOE's) Hanford Site in a variety of locations, including subsurface grout and tank farms, solid waste burial grounds, and contaminated soil sites. Some of these waste sites may need to be isolated from percolating water to minimize the potential for transport of the waste to the ground water, which eventually discharges to the Columbia River. Multilayer protective barriers have been proposed as a means of limiting the flow of water through the waste sites (DOE 1987). A multiyear research program (managed jointly by Pacific Northwest Laboratory (PNL) and Westinghouse Hanford Company for the DOE) is aimed at assessing the performance of these barriers. One aspect of this program involves the use of computer models to predict barrier performance. Three modeling studies have already been conducted and a test plan was produced. The simulation work reported here was conducted by PNL and extends the previous modeling work. The purpose of this report are to understand phenomena that have been observed in the field and to provide information that can be used to improve hydrologic modeling of the protective barrier. An improved modeling capability results in better estimates of barrier performance. Better estimates can be used to improve the design of barriers and the assessment of their long-term performance.

  1. Stem thrust prediction model for Westinghouse wedge gate valves with linkage type stem-to-disk connection

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.K.; Sharma, V.; Kalsi, M.S. [Kalsi Engineering, Inc., Sugar Land, TX (United States)] [and others

    1996-12-01

    The Electric Power Research Institute (EPRI) conducted a comprehensive research program with the objective of providing nuclear utilities with analytical methods to predict motor operated valve (MOV) performance under design basis conditions. This paper describes the stem thrust calculation model developed for evaluating the performance of one such valve, the Westinghouse flexible wedge gate valve. These procedures account for the unique functional characteristics of this valve design. In addition, model results are compared to available flow loop and in situ test data as a basis for evaluating the performance of the valve model.

  2. X-231A demonstration of in-situ remediation of DNAPL compounds in low permeability media by soil fracturing with thermally enhanced mass recovery or reactive barrier destruction

    Energy Technology Data Exchange (ETDEWEB)

    Siegrist, R.L. [Oak Ridge National Lab., TN (United States)]|[Colorado School of Mines, Golden, CO (United States). Environmental Science and Engineering Div.; Lowe, K.S. [Oak Ridge National Lab., Grand Junction, CO (United States). Life Sciences Div.; Murdoch, L.D. [FRx, Inc., Cincinnati, OH (United States)]|[Clemson Univ., SC (United States); Slack, W.W. [FRx, Inc., Cincinnati, OH (United States); Houk, T.C. [Lockheed Martin Energy Systems, Piketon, OH (United States)

    1998-03-01

    The overall goal of the program of activities is to demonstrate robust and cost-effective technologies for in situ remediation of DNAPL compounds in low permeability media (LPM), including adaptations and enhancements of conventional technologies to achieve improved performance for DNAPLs in LPM. The technologies sought should be potential for application at simple, small sites (e.g., gasoline underground storage tanks) as well as at complex, larger sites (e.g., DOE land treatment units). The technologies involved in the X-231A demonstration at Portsmouth Gaseous Diffusion Plant (PORTS) utilized subsurface manipulation of the LPM through soil fracturing with thermally enhanced mass recovery or horizontal barrier in place destruction. To enable field evaluation of these approaches, a set of four test cells was established at the X-231A land treatment unit at the DOE PORTS plant in August 1996 and a series of demonstration field activities occurred through December 1997. The principal objectives of the PORTS X-231A demonstration were to: determine and compare the operational features of hydraulic fractures as an enabling technology for steam and hot air enhanced soil vapor extraction and mass recovery, in situ interception and reductive destruction by zero valent iron, and in situ interception and oxidative destruction by potassium permanganate; determine the interaction of the delivered agents with the LPM matrix adjacent to the fracture and within the fractured zone and assess the beneficial modifications to the transport and/or reaction properties of the LPM deposit; and determine the remediation efficiency achieved by each of the technology strategies.

  3. The Westinghouse AP1000 plant design: a generation III+ reactor with unique proven passive safety technology

    Energy Technology Data Exchange (ETDEWEB)

    Demetri, K. J.; Leipner, C. I.; Marshall, M. L., E-mail: demetrkj@westinghouse.com [Westinghouse Electric Company, 1000 Westinghouse Drive, Cranberry Township, PA 16066 (United States)

    2015-09-15

    The AP1000 plant is an 1100-M We pressurized water reactor with passive safety features and extensive plant simplifications and standardization that simplify construction, operation, maintenance, safety, and cost. The AP1000 plant is based on proven pressurized water reactor (PWR) technology, with an emphasis on safety features that rely solely on natural forces. These passive safety features are combined with simple, active, defense-in-depth systems used during normal plant operations which also provide the first level of defense against more probable events. This paper focuses on specific safety and licensing topics: the AP1000 plant robustness to be prepared for extreme events that may lead to catastrophic loss of infrastructure, such as the Fukushima Dai-ichi event, and the AP1000 plant compliance with the safety objectives for new plants. The first deployment of the AP1000 plant formally began in July 2007 when Westinghouse Electric Company and its consortium partner, the Shaw Group, signed contracts for four AP1000 units on coastal sites of Sanmen and Haiyang, China. Both sites have the planned ability to accommodate at least six AP1000 units; construction is largely concurrent for all four units. Additionally, the United States (U.S.) Nuclear Regulatory Commission (NRC) issued combined licenses (COLs) to allow Southern Nuclear Operating Company (SNC) and South Carolina Electric and Gas Company (SCE and G) to construct and operate AP1000 plants. Within this paper, the various factors that contribute to an unparalleled level of design, construction, delivery, and licensing certainty for any new AP1000 plant projects are described. These include: 1) How the AP1000 plant design development and reviews undertaken in the United States, China and Europe increase licensing certainty. 2) How the AP1000 passive plant robustness against extreme events that result in large loss of infrastructure further contributes to the licensing certainty in a post

  4. Non-Thermal Dielectric Barrier Discharge (DBD Effects on Proliferation and Differentiation of Human Fibroblasts Are Primary Mediated by Hydrogen Peroxide.

    Directory of Open Access Journals (Sweden)

    Julian Balzer

    Full Text Available The proliferation of fibroblasts and myofibroblast differentiation are crucial in wound healing and wound closure. Impaired wound healing is often correlated with chronic bacterial contamination of the wound area. A new promising approach to overcome wound contamination, particularly infection with antibiotic-resistant pathogens, is the topical treatment with non-thermal "cold" atmospheric plasma (CAP. Dielectric barrier discharge (DBD devices generate CAP containing active and reactive species, which have antibacterial effects but also may affect treated tissue/cells. Moreover, DBD treatment acidifies wound fluids and leads to an accumulation of hydrogen peroxide (H2O2 and nitric oxide products, such as nitrite and nitrate, in the wound. Thus, in this paper, we addressed the question of whether DBD-induced chemical changes may interfere with wound healing-relevant cell parameters such as viability, proliferation and myofibroblast differentiation of primary human fibroblasts. DBD treatment of 250 μl buffered saline (PBS led to a treatment time-dependent acidification (pH 6.7; 300 s and coincidently accumulation of nitrite (~300 μM, nitrate (~1 mM and H2O2 (~200 μM. Fibroblast viability was reduced by single DBD treatments (60-300 s; ~77-66% or exposure to freshly DBD-treated PBS (60-300 s; ~75-55%, accompanied by prolonged proliferation inhibition of the remaining cells. In addition, the total number of myofibroblasts was reduced, whereas in contrast, the myofibroblast frequency was significantly increased 12 days after DBD treatment or exposure to DBD-treated PBS. Control experiments mimicking DBD treatment indicate that plasma-generated H2O2 was mainly responsible for the decreased proliferation and differentiation, but not for DBD-induced toxicity. In conclusion, apart from antibacterial effects, DBD/CAP may mediate biological processes, for example, wound healing by accumulation of H2O2. Therefore, a clinical DBD treatment must be well

  5. Non-Thermal Dielectric Barrier Discharge (DBD) Effects on Proliferation and Differentiation of Human Fibroblasts Are Primary Mediated by Hydrogen Peroxide

    Science.gov (United States)

    Demir, Erhan; Hoffmanns, Martin A.; Baldus, Sabrina; Fuchs, Paul C.; Awakowicz, Peter; Suschek, Christoph V.; Opländer, Christian

    2015-01-01

    The proliferation of fibroblasts and myofibroblast differentiation are crucial in wound healing and wound closure. Impaired wound healing is often correlated with chronic bacterial contamination of the wound area. A new promising approach to overcome wound contamination, particularly infection with antibiotic-resistant pathogens, is the topical treatment with non-thermal “cold” atmospheric plasma (CAP). Dielectric barrier discharge (DBD) devices generate CAP containing active and reactive species, which have antibacterial effects but also may affect treated tissue/cells. Moreover, DBD treatment acidifies wound fluids and leads to an accumulation of hydrogen peroxide (H2O2) and nitric oxide products, such as nitrite and nitrate, in the wound. Thus, in this paper, we addressed the question of whether DBD-induced chemical changes may interfere with wound healing-relevant cell parameters such as viability, proliferation and myofibroblast differentiation of primary human fibroblasts. DBD treatment of 250 μl buffered saline (PBS) led to a treatment time-dependent acidification (pH 6.7; 300 s) and coincidently accumulation of nitrite (~300 μM), nitrate (~1 mM) and H2O2 (~200 μM). Fibroblast viability was reduced by single DBD treatments (60–300 s; ~77–66%) or exposure to freshly DBD-treated PBS (60–300 s; ~75–55%), accompanied by prolonged proliferation inhibition of the remaining cells. In addition, the total number of myofibroblasts was reduced, whereas in contrast, the myofibroblast frequency was significantly increased 12 days after DBD treatment or exposure to DBD-treated PBS. Control experiments mimicking DBD treatment indicate that plasma-generated H2O2 was mainly responsible for the decreased proliferation and differentiation, but not for DBD-induced toxicity. In conclusion, apart from antibacterial effects, DBD/CAP may mediate biological processes, for example, wound healing by accumulation of H2O2. Therefore, a clinical DBD treatment must be well

  6. DOSE RATES FOR WESTINGHOUSE 17X17 MOX PWR SNF IN A WASTE PACKAGE (SCPB: N/A)

    Energy Technology Data Exchange (ETDEWEB)

    T.L. Lotz

    1997-01-29

    This analysis is prepared by the Mined Geologic Disposal System (MGDS) Waste Package Development Department (WPDD) to estimate the dose rate on and near the surface a Multi-Purpose Canister (MPC) PWR waste package (WP) which is loaded with Westinghouse 17 x 17 mixed oxide (MOX) PWR fuel. The 21 PWR MPC WP is used to provide an upper bound for waste package designs since the 12 PWR MPC WP will have a smaller source term and an equivalent amount of shielding. the objectives of this evaluation are to calculate the requested dose rate(s) and document the calculation in a fashion to allow comparisons to other waste forms and WP designs at a future time.

  7. Sensitivity analysis for thermo-hydraulics model of a Westinghouse type PWR. Verification of the simulation results

    Energy Technology Data Exchange (ETDEWEB)

    Farahani, Aref Zarnooshe [Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Dept. of Nuclear Engineering, Science and Research Branch; Yousefpour, Faramarz [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of); Hoseyni, Seyed Mohsen [Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Dept. of Basic Sciences; Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Young Researchers and Elite Club

    2017-07-15

    Development of a steady-state model is the first step in nuclear safety analysis. The developed model should be qualitatively analyzed first, then a sensitivity analysis is required on the number of nodes for models of different systems to ensure the reliability of the obtained results. This contribution aims to show through sensitivity analysis, the independence of modeling results to the number of nodes in a qualified MELCOR model for a Westinghouse type pressurized power plant. For this purpose, and to minimize user error, the nuclear analysis software, SNAP, is employed. Different sensitivity cases were developed by modification of the existing model and refinement of the nodes for the simulated systems including steam generators, reactor coolant system and also reactor core and its connecting flow paths. By comparing the obtained results to those of the original model no significant difference is observed which is indicative of the model independence to the finer nodes.

  8. Interface for Consolidated Edison's Waterside Station compact simulator -- PC-TRAX to Westinghouse Distributed Processing Family

    Energy Technology Data Exchange (ETDEWEB)

    Whitehead, T.J.; Pierce, W.R.; Roberts, R.C. (Science Applications International Corp., Idaho Falls, ID (United States))

    1993-04-01

    Many fossil power plants are upgrading to modern digital control systems. Engineers must design and debug these new systems, and operators must train to use them. Simulators make it possible to prove designs and train operators before new controls are put into operation. EPRI compact simulator technology is especially desirable for these purposes because it uses PC platforms and modern simulation systems. The PC platform is inexpensive, and the simulation software is modular so new configurations can be easily generated and evaluated. To enhance and demonstrate compact simulator technology and its associated benefits; to develop an interface between the PC-TRAC simulation system and a Westinghouse Distributed Processing Family (WDPF) control system that allows spare control system equipment to be used as part of a simulator; to demonstrate a unit-specific simulator for Waterside Station for use in training and controls engineering.

  9. Building barriers.

    Science.gov (United States)

    Turksen, Kursad

    2017-10-02

    Formation of tissue barriers starts in early development where it is critical for normal cell fate selection, differentiation and organogenesis. Barrier maintenance is critical to the ongoing function of organs during adulthood and aging. Dysfunctional tissue barrier formation and function at any stage of the organismal life cycle underlies many disease states.

  10. Structure design of the Westinghouse superconducting magnet for the Large Coil Program

    Energy Technology Data Exchange (ETDEWEB)

    Domeisen, F.N.; Hackworth, D.T.; Stuebinger, L.R.

    1978-01-01

    In the on-going development of superconducting toroidal field coils for tokamak reactors, the Large Coil Program (LCP) managed by Union Carbide Corporation will include the design, fabrication, and testing of large superconducting coils to determine their feasibility for use in the magnetic fusion energy effort. Structural analysis of the large coil is essential to ensure adequate safety in the test coil design and confidence in the scalability of the design. This paper will discuss the action of tensile and shear loads on the various materials used in the coil. These loads are of magnetic and thermal origin.

  11. Long-Term Climate Change Assessment Task for the Hanford Site Permanent Isolation Barrier Development Program: Status through FY 1992

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, K.L. [Westinghouse Hanford Co., Richland, WA (US); Chatters, J.C. [Pacific Northwest Lab., Richland, WA (US)

    1993-07-01

    The Hanford Site Permanent Isolation Barrier Development Program (Barrier Development Program) was organized (Adams and Wing 1986) to develop the technology needed to provide an in-place disposal capability for the US Department of Energy at the Hanford Site in southeastern Washington. The goals of the Barrier Development Program are to provide defensible evidence that final barrier design(s) will adequately control water infiltration, plant and animal intrusion, and wind and water erosion for a minimum of 1,000 years; to isolate wastes from the accessible environment; and to use markers to warn inadvertent human intruders. Evidence for barrier performance will be obtained by conducting laboratory experiments, field tests, computer modeling, and other studies that establish confidence in the barrier`s ability to meet its 1,000-year design life. The performance and stability of natural barrier analogs that have existed for several millennia and the reconstruction of climate changes during the past 10,000 to 125,000 years also will provide insight into bounding conditions of possible future changes and increase confidence in the barriers design. In the following discussion the term {open_quotes}long-term{close_quotes} references periods of time up to 1000`s of years, distinguishing it from {open_quotes}short-term{close_quotes} weather patterns covering a decade or less. Specific activities focus on planning and conducting a series of studies and tests required to confirm key aspects of the barrier design. The effort is a collaborative one between scientists and engineers from Westinghouse Hanford Company (Westinghouse Hanford) and Pacific Northwest Laboratory (PNL) to design barriers to limit movement of radionuclides and other contaminants to the accessible environment for at least 1,000 years. These activities have been divided into 14 groups of tasks that aid in the complete development of protective barrier and warning marker system.

  12. Altitude-Wind-Tunnel Investigation of Westinghouse 19B-2 19B-8, and 19XB-1 Jet-Propulsion Engines. Part 1; Operational Characteristics

    Science.gov (United States)

    Fleming, William A.

    1948-01-01

    An investigation was conducted in the NACA Cleveland altitude wind tunnel to determine the operational characteristics of the Westinghouse 19B-2, 19B-8, and 19XB-l jet-propulsion engines. The 19B engine is one af the earliest experimental Westinghouse axial flow engines. The 19XB-1 engine is an experimental prototype of the Westinghouse 15 series, having a rated thrust of 1400 pounds. Improvements in performance and operational characteristics have resulted in the 19XB-2B engine with a rated thrust of 1600 pounds. The operational characteristics were determined over a range of simulated altitudes from 5000 to 30,000 feet for the 19B engines and from 5000 to 35000 feet for the 19XB-l engine at airspeed from 20 to 380 miles per hour. The affects of altitude and airspeed on such operating characteristics as operating range, stability of combustion, starting, acceleration, and functioning of the fuel-control system are discussed. Damage to the engines that occurred during the investigation is also briefly discussed. The changes made in the combustion-chamber configuration to improve the operating we are described.

  13. Ichthyoplankton entrainment study at the SRS Savannah River water intakes for Westinghouse Savannah River Company. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Paller, M. [Westinghouse Savannah River Co., Aiken, SC (United States)

    1992-03-26

    Cooling water for L and K Reactors and makeup water for Par Pond is pumped from the Savannah River at the 1G, 3G, and 5G pump houses. Ichthyoplankton (drifting fish larvae and eggs) from the river are entrained into the reactor cooling systems with the river water and passed through the reactor`s heat exchangers where temperatures may reach 70{degrees}C during full power operation. Ichthyoplankton mortality under such conditions is assumed to be 100 percent. The number of ichthyoplankton entrained into the cooling system depends on a variety of variables, including time of year, density and distribution of ichthyoplankton in the river, discharge levels in the river, and the volume of water withdrawn by the pumps. Entrainment at the 1 G pump house, which is immediately downstream from the confluence of Upper Three Runs Creek and the Savannah River, is also influenced by discharge rates and ichthyoplankton densities in Upper Three Runs Creek. Because of the anticipated restart of several SRS reactors and the growing concern surrounding striped bass and American shad stocks in the Savannah River, the Department of Energy requested that the Environmental Sciences Section (ESS) of the Savannah River Laboratory sample ichthyoplankton at the SRS Savannah River intakes. Dams & Moore, Inc., under a contract with Westinghouse Savannah River Company performed the sampling and data analysis for the ESS.

  14. Westinghouse Hanford Company ALARA year-end report, Calendar Year 1994: Revision 3A, Radiological engineering and ALARA

    Energy Technology Data Exchange (ETDEWEB)

    Berglund, O.D.

    1995-06-01

    It has long been the US Department of Energy`s (DOE`s) Policy that radiation doses should be maintained as far below the dose limits as is reasonably achievable. This policy, known as the ``ALARA Principle of radiation protection,`` maintains that radiation exposures should be maintained as low as reasonably achievable, taking into account social, technical, economic, practical, and public policy considerations. The ALARA Principle is based on the hypothesis that even very low radiation doses carry some risk. As a result, it is not enough to maintain doses at/or slightly below limits; the lower the doses, the lower the risks. Because it is not possible to reduce all doses at DOE facilities to zero, economic and social factors must be considered to determine the optimal level of radiation doses. According to the ALARA Principle, if doses are too high, resources should be well spent to reduce them. At some point, the resources being spent to maintain low doses are exactly balanced by the risks avoided. Reducing doses below this point results in a misallocation of resources; the resources could be spent elsewhere and have a greater positive impact on health and safety. The objective of the Westinghouse Hanford Company (WHC) ALARA/Contamination Control Improvement Project (CCIP) Program is to manage and control exposures (both individual and collective) to the work force, the general public, and the environment to levels as low as is reasonable using the aforementioned ALARA Principle.

  15. Mechanical Properties and Real-Time Damage Evaluations of Environmental Barrier Coated SiC/SiC CMCs Subjected to Tensile Loading Under Thermal Gradients

    Science.gov (United States)

    Appleby, Matthew; Zhu, Dongming; Morscher, Gregory

    2015-01-01

    SiC/SiC ceramic matrix composites (CMCs) require new state-of-the art environmental barrier coatings (EBCs) to withstand increased temperature requirements and high velocity combustion corrosive combustion gasses. The present work compares the response of coated and uncoated SiC/SiC CMC substrates subjected to simulated engine environments followed by high temperature mechanical testing to asses retained properties and damage mechanisms. Our focus is to explore the capabilities of electrical resistance (ER) measurements as an NDE technique for testing of retained properties under combined high heat-flux and mechanical loading conditions. Furthermore, Acoustic Emission (AE) measurements and Digital Image Correlation (DIC) were performed to determine material damage onset and accumulation.

  16. Non-thermal activation of the hsp27/p38MAPK stress pathway by mobile phone radiation in human endothelial cells: molecular mechanism for cancer- and blood-brain barrier-related effects.

    Science.gov (United States)

    Leszczynski, Dariusz; Joenväärä, Sakari; Reivinen, Jukka; Kuokka, Reetta

    2002-05-01

    We have examined whether non-thermal exposures of cultures of the human endothelial cell line EA.hy926 to 900 MHz GSM mobile phone microwave radiation could activate stress response. Results obtained demonstrate that 1-hour non-thermal exposure of EA.hy926 cells changes the phosphorylation status of numerous, yet largely unidentified, proteins. One of the affected proteins was identified as heat shock protein-27 (hsp27). Mobile phone exposure caused a transient increase in phosphorylation of hsp27, an effect which was prevented by SB203580, a specific inhibitor of p38 mitogen-activated protein kinase (p38MAPK). Also, mobile phone exposure caused transient changes in the protein expression levels of hsp27 and p38MAPK. All these changes were non-thermal effects because, as determined using temperature probes, irradiation did not alter the temperature of cell cultures, which remained throughout the irradiation period at 37 +/- 0.3 degrees C. Changes in the overall pattern of protein phosphorylation suggest that mobile phone radiation activates a variety of cellular signal transduction pathways, among them the hsp27/p38MAPK stress response pathway. Based on the known functions of hsp27, we put forward the hypothesis that mobile phone radiation-induced activation of hsp27 may (i) facilitate the development of brain cancer by inhibiting the cytochrome c/caspase-3 apoptotic pathway and (ii) cause an increase in blood-brain barrier permeability through stabilization of endothelial cell stress fibers. We postulate that these events, when occurring repeatedly over a long period of time, might become a health hazard because of the possible accumulation of brain tissue damage. Furthermore, our hypothesis suggests that other brain damaging factors may co-participate in mobile phone radiation-induced effects.

  17. Hanford Site Long-term Surface Barrier Development Program: Fiscal year 1994 highlights

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, K.L.; Link, S.O.; Gee, G.W.

    1995-08-01

    The Hanford Site Surface Barrier Development Program was organized in 1985 to test the effectiveness of various barrier designs in minimizing the effects of water infiltration; plant, animal and human intrusion; and wind and water erosion on buried wastes, plus preventing or minimizing the emanation of noxious gases. A team of scientists from the Pacific Northwest Laboratory (PNL) and engineers from Westinghouse Hanford Company (WHC) direct the barrier development effort. ICF Kaiser Hanford Company, in conjunction with WHC and PNL, developed design drawings and construction specifications for a 5-acre prototype barrier. The highlight of efforts in FY 1994 was the construction of the prototype barrier. The prototype barrier was constructed on the Hanford Site at the 200 BP-1 Operable Unit of the 200 East Area. Construction was completed in August 1994 and monitoring instruments are being installed so experiments on the prototype barrier can begin in FY 1995. The purpose of the prototype barrier is to provide insights and experience with issues regarding barrier design, construction, and performance that have not been possible with individual tests and experiments conducted to date. Additional knowledge and experience was gained in FY 1994 on erosion control, physical stability, water infiltration control, model testing, Resource Conservation and Recovery Act (RCRA) comparisons, biointrusion control, long-term performance, and technology transfer.

  18. Dynamics of energy coupling and thermalization in barrier discharges over dielectric and weakly conducting surfaces on µs to ms time scales

    Science.gov (United States)

    Leonov, Sergey B.; Petrishchev, Vitaly; Adamovich, Igor V.

    2014-11-01

    The paper presents experiments characterizing discharge development and energy coupling in a surface dielectric barrier discharge (SDBD), atmospheric air plasmas over dielectric and weakly conducting surfaces, over a wide range of time scales and electrical conductivities. The experiments are done using nanosecond pulse (NS) both single polarity and alternating polarity) and ac voltage waveforms. Discharge development and mechanisms of coupling with quiescent air are analysed using nanosecond gate camera imaging, schlieren imaging, and laser differential interferometry. It is shown that NS SDBD plasmas generate stochastic, localized, near-surface perturbations on a long time scale (>100 μs) after the discharge pulse. These perturbations, entirely different from compression waves generated on a short time scale (~1-10 μs), are caused by discharge contraction and originate from the ends of the filaments. Surface conductivity has almost no effect on discharge behaviour if RC time of the conducting surface layer is much longer compared to the characteristic time of NS or ac voltage waveforms. In the opposite limit of short RC time, the conducting layer acts as an extension of the high-voltage electrode. Discharge contraction significantly increases energy stored on the dielectric surface, which in this case exceeds energy dissipated as Joule heat. The stored energy is dissipated if the discharge pulse is followed by an opposite polarity pulse. In a single polarity discharge, on the other hand, surface charge accumulation limits energy coupled to the plasma by subsequent pulses. The results demonstrate that surface plasma actuator control authority may be significantly increased by using an alternating polarity pulse waveform, which is more effective than the removal of surface charge between the pulses using a weakly conducting surface.

  19. Organizational barriers

    Science.gov (United States)

    Kenneth S. Blonski

    1995-01-01

    One of the traditional roles that prescribed fire has played in the fire management arena is reduction of hazardous fuel buildups under controlled, well-defined environmental conditions. However, our ability to use this tool effectively is blocked by many barriers. The preceding panel discussion about the causes of limited success in implementing prescribed burning...

  20. Hanford Site Permanent Isolation Surface Barrier Development Program: Fiscal year 1992 and 1993 highlights

    Energy Technology Data Exchange (ETDEWEB)

    Cadwell, L.L.; Link, S.O.; Gee, G.W. [eds.

    1993-09-01

    The Hanford Site Permanent Isolation Surface Barrier Development Program was jointly developed by the Pacific Northwest Laboratory and Westinghouse Hanford Company to design and test an earthen cover system that can be used to inhibit water infiltration; plant, animal, and human intrusion; and wind and water erosion. Kaiser Engineers Hanford Company provided engineering design support for the program. Work on barrier design has been under way at Hanford for nearly 10 years. The comprehensive development of a long-term barrier, formerly the Hanford Site Protective Barrier Development Program, was initiated in FY 1986, and a general field-tested design is expected to be completed by FY 1998. Highlights of efforts in FY 1992 and FY 1993 included the resumption of field testing, the completion of the prototype barrier design, and the convening of an external peer review panel, which met twice with the barrier development team. The review panel provided helpful guidance on current and future barrier development activities, while commending the program for its significant technical contributions to innovative barrier technology development.

  1. Air Plasma-Sprayed La2Zr2O7-SrZrO3 Composite Thermal Barrier Coating Subjected to CaO-MgO-Al2O3-SiO2 (CMAS)

    Science.gov (United States)

    Cai, Lili; Ma, Wen; Ma, Bole; Guo, Feng; Chen, Weidong; Dong, Hongying; Shuang, Yingchai

    2017-08-01

    La2Zr2O7-SrZrO3 composite thermal barrier coatings (TBCs) were prepared by air plasma spray (APS). The La2Zr2O7-SrZrO3 composite TBCs covered with calcium-magnesium-aluminum-silicate (CMAS) powder, as well as the powder mixture of CMAS and spray-dried La2Zr2O7-SrZrO3 composite powder, were heat-treated at 1250 °C in air for 1, 4, 8, and 12 h. The phase constituents and microstructures of the reaction products were characterized by x-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. Experimental results showed that the La2Zr2O7-SrZrO3 composite TBCs had higher CMAS resistance than 8YSZ coating. A dense new layer developed between CMAS and La2Zr2O7-SrZrO3 composite TBCs during interaction, and this new layer consisted mostly of apatite (Ca2La8(SiO4)6O2) and c-ZrO2. The newly developed layer effectively protected the La2Zr2O7-SrZrO3 composite TBCs from further CMAS attack.

  2. Simulation of station blackout scenario in low-power and shutdown condition of Westinghouse two-loop plant with RELAP5 code

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Se Yun; Ha, Sang Jun [KHNP Central Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    A station blackout scenario in low power and shutdown condition of Westinghouse two-loop plant is simulated with RELAP5 code. To evaluate plant safety in station blackout scenario for low-power and shutdown condition, the transient calculation with RELAP5 code has been carried out for a Westinghouse two-loop plant. Without core cooling, the boiling in core and spent fuel pit occurs. The core uncovery is observed about 160 hours and the peak cladding temperature exceeds 1206K at 161.1. Station blackout is the complete loss of alternating current (AC) electrical power to the essential and nonessential switchgear buses in a nuclear power plant. Because many safety systems required for reactor core cooling and containment heat removal depend on AC power, the consequences of a station blackout could be severe. Especially, station blackout in low-power and shutdown condition is one of the current issues. Therefore, the evaluation of plant safety with safety analysis code is opportune.

  3. Influence of bondcoat composition and manufacturing parameters on the lifetime of thermal barrier coatings under cyclic temperature loading; Einfluss der Bondcoatzusammensetzung und Herstellungsparameter auf die Lebensdauer von Waermedaemmschichten bei zyklischer Temperaturbelastung

    Energy Technology Data Exchange (ETDEWEB)

    Subanovic, Marko

    2008-08-21

    In the present study the influence of the bond coat composition on the lifetime of thermal barrier coatings during thermal cycling was investigated. The knowledge, that the reactive elements (RE), which are essential for the improvement of the oxide scale adhesion, are ''lost'', during the bond coat processing, made it necessary to investigate systematically the influence of the different manufacturing stages on the RE distribution. After VPS (vacuum plasma spraying) with a high oxygen partial pressure in the spraying chamber, the reactive elements in the NiCoCrAl-coating were tied up in oxide precipitates, and thus their beneficial effect on the scale adhesion was inhibited. Another important observation is that the RE's are depleted during the bondcoat vacuum heat-treatment. The degree of Y-depletion depends not only on the Y-reservoir in the coating (Y-content and thickness) but also on the heat-treatment parameters, such as vacuum quality and temperature. A thin, dense alumina oxide scale with a smooth interface between bond coat and TGO doesn't necessary lead to a lifetime extension of the EB-PVD TBC's. TBC's with such oxide morphology typically failed due to crack formation and propagation along the interface between the TGO and the bondcoat. By addition of zirconium it was possible to shift the failure initiation from the interface TGO/bondcoat to the interface TBC/TGO, which can apparently accommodate more thermal strain energy before failure. The shift of the failure location was achieved by a change of the oxide morphology, which mainly relies on adjusting a non-even wavy interface between the TGO and the bond coat and formation of defected oxide layers. In contrast, a defected oxide scale with a high growth rate shortened the life time of APSTBC's. Porosity and spinel formation weakened the mechanical integrity of the oxide scale, and facilitated the crack formation and propagation of the already existing

  4. Stiffness of Plasma Sprayed Thermal Barrier Coatings

    National Research Council Canada - National Science Library

    Shiladitya Paul

    2017-01-01

    .... In this paper, the Young’s modulus of TBC top coat, measured using different techniques, such as four-point bending, indentation and impulse excitation is reported, along with a brief description of how the techniques probe...

  5. Radiative Transport Modelling of Thermal Barrier Coatings

    Science.gov (United States)

    2017-03-24

    Figure 1. Schematic of multiple scatter events inside a TBC D l1 l2 l3 l4l5 5 Two random walk simulation codes were adapted and improved upon, one...one particular n = 2 scatter event. l1 lb 1 2 l2 db DISTRIBUTION A. Approved for public release: distribution unlimited. 11 The solution to Eq. (13...development of the new model (Task 2) and in testing it (Task 3). Some model parameter definitions are shown in Figure 1. The scattering medium is

  6. Projects of Modifications of design for mitigation of accidents outside the design Bases on nuclear Central PWR Siemens-KWU and Westinghouse; Proyectos de Modificaciones de Sieno para Mitigacion de Accidentes fuera de la Bases de Diseno en Centrales Nucleares PWR Siemens-KWU y Westinghouse

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez Gonzalez, G.; Cano Rodriguez, L. A.; Arguello Tara, A.

    2014-07-01

    Following the accident at the Japanese Fukushima-Daiichi NPP, the different regulators of nuclear power generation have required numerous reports regarding the evaluation and modification of the capacity of the plants to face accidents with severities beyond that established in their Design Bases. Under this new scenario, with multiple new demands and commitments, EA has carried out the required works for the implementation of strategies to mitigate the consequences of beyond Design Basis accidents for utilities owning Siemens-KWU and Westinghouse PWR nuclear power plants. (Author)

  7. Final evaluation report for Westinghouse Hanford Company, WRAP-1,208 liter waste drum, docket 94-35-7A, type A packaging

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, D.L., Westinghouse Hanford

    1996-06-12

    This report documents the U.S. Department of Transportation Specification 7A Type A (DOT-7A) compliance test results of the Westinghouse Hanford Company, Waste Receiving and Processing Facility, Module 1 (WRAP-1) Drum. The WRAP-1 Drum was tested for DOE-HQ in August 1994, by Los Alamos National Laboratory, under docket number 94-35-7A. Additionally, comparison and evaluation of the approved, as-tested packaging configuration was performed by WHC in September 1995. The WRAP-1 Drum was evaluated against the performance of the DOT-17C, 208 1 (55-gal) steel drums tested and evaluated under dockets 89-13-7A/90-18-7A and 94-37-7A.

  8. Model assessment of protective barriers: Part 3. Status of FY 1990 work

    Energy Technology Data Exchange (ETDEWEB)

    Fayer, M.J.; Rockhold, M.L.; Holford, D.J.

    1992-02-01

    Radioactive waste exists at the US Department of Energy`s (DOE`s) Hanford Site in a variety of locations, including subsurface grout and tank farms, solid waste burial grounds, and contaminated soil sites. Some of these waste sites may need to be isolated from percolating water to minimize the potential for transport of the waste to the ground water, which eventually discharges to the Columbia River. Multilayer protective barriers have been proposed as a means of limiting the flow of water through the waste sites (DOE 1987). A multiyear research program [managed jointly by Pacific Northwest Laboratory (PNL) and Westinghouse Hanford Company for the DOE] is aimed at assessing the performance of these barriers. One aspect of this program involves the use of computer models to predict barrier performance. Three modeling studies have already been conducted and a test plan was produced. The simulation work reported here was conducted by PNL and extends the previous modeling work. The purpose of this report are to understand phenomena that have been observed in the field and to provide information that can be used to improve hydrologic modeling of the protective barrier. An improved modeling capability results in better estimates of barrier performance. Better estimates can be used to improve the design of barriers and the assessment of their long-term performance.

  9. Development of engineered barrier

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Kwan Sik; Cho, Won Jin; Lee, Jae Owan; Kim, Seung Soo; Kang, Mu Ja

    1999-03-01

    Engineered barrier development was carried out into the three research fields : waste form, disposal container, and buffer. The waste form field dealt with long-term leaching tests with borosilicate waste glasses surrounded by compacted bentonite. The leach rate decreased with increasing time, and was higher for the waste specimen rich in U and Na. In the container field, preliminary concepts of disposal containers were recommended by conducting structural analysis, thermal analysis, and shielding analysis, and major properties of stainless steel, copper, and titanium as a container material were surveyed. The sensitization degrees of SUS 316 and316L were lower than those of SUS 304 and 304L, respectively. The crevice corrosion of sensitized stainless steel was sensitive to the content of salt. Researches into the buffer included establishment of its performance criteria followed by investigating major properties of buffer using potential material in Korea. Experiments were made for measuring hydraulic conductivities, swelling properties, mechanical properties, thermal conductivities, pore-water chemistry properties, and adsorption properties was also investigated. (author)

  10. Concentrated solar thermal power - Now

    Energy Technology Data Exchange (ETDEWEB)

    Aringhoff, R.; Brakmann, G. [Solar Thermal Power Industry Association ESTIA, Avenue de la Fauconnerie 73, 1170 Brussels (Belgium); Geyer, M. [IEA SolarPACES Implementing Agreement, Avenida de la Paz 51, 04720 Aguadulce, Almeria (Spain); Teske, S. [Greenpeace International, Ottho Heldringstraat 5, 1066 AZ Amsterdam (Netherlands)

    2005-09-15

    This report demonstrates that there are no technical, economic or resource barriers to supplying 5% of the world's electricity needs from solar thermal power by 2040. It is written as practical blueprint to improve understanding of the solar thermal contribution to the world energy supply.

  11. Optimization of APS-ZrO{sub 2}-thermal barrier coatings by variations of creep strength and interface roughness; Optimierung von APS-ZrO{sub 2}-Waermedaemmschichten durch Variationen der Kriechfestigkeit und der Grenzflaechenrauhigkeit

    Energy Technology Data Exchange (ETDEWEB)

    Schweda, Mario

    2011-07-01

    Gas turbines operate at combustion chamber temperatures up to 1400 C. Therefore the blades and the combustion chamber lining, which consist of Ni-superalloys for highest loads, are coated with a thermal barrier coating (TBC) of zirconium oxide and an underlying oxidation protection coating of MCrAlY-alloys (M=Ni, Co). At high temperature the MCrAlY-coating oxidizes and an Al{sub 2}O{sub 3}-scale (thermally grown oxide, TGO) forms between MCrAlY-coating and TBC, what constrains the oxidation of the base material. At plasma sprayed TBCs, the MCrAlY-coating provides a bond coat (BC) for the TBC at the same time and therefore is roughened by sandblasting before the deposition of the TBC. By the growth of the Al{sub 2}O{sub 3}-scale and the start up and run down of the gas turbine, stresses arise in the TBC, which lead to lateral crack formation in the field of the TBC-BC-interface and finally to the spallation of the TBC. Thereby other parts of the turbine can be damaged, what causes high costs. Therefrom the aim is to delay the crack growth as strong as possible or rather to maximize the lifetime of the TBC. For this purpose the material properties of the coating components have to be optimized. In the present work, the influence of creep strength of BC and TGO and the influence of TBC-BC-interface-roughness on the lifetime and damage evolution of plasma sprayed ZrO{sub 2}-TBCs are investigated. To determine the lifetime, cylindrical specimens with plasma sprayed ZrO{sub 2}-TBC were produced and thermally cycled with a minimum and maximum temperature of 60 C and 1050 C and a dwell time at maximal temperature of 2h. To exclude the interdiffusion and thermal mismatch between BC and Ni-superalloy, a model system was used: The Ni-superalloy was left and the substrate material consists completely of a BC-like FeCrAlY-alloy. The model system was simulated by the project partner TU Braunschweig with the FE-method. The TBC-BC-interface-roughness was abstracted by a 2

  12. Smart structures for application in ceramic barrier filter technology. Final report, August 1991--August 1994

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, S.J.; Lippert, T.E

    1994-12-01

    High temperature optical fiber sensors were developed to measure the in-service stressing that occurs in ceramic barrier filter systems. The optical fiber sensors were based on improvements to the sensor design developed under the DOE/METC Smart Structures for Fossil Energy Applications contract no. DE-AC21-89MC25159. In-house application testing of these sensors on both candle and cross-flow filters were performed in the Westinghouse Science and Technology Center High-Temperature, High-Pressure Filter Test Facility and the results analyzed. This report summarizes the sensor developments, methods to apply the sensors to the filters for in-situ testing, and the test results from the four in-house tests that were performed.

  13. Wet processing of palladium for use in the tritium facility at Westinghouse, Savannah River, SC. Preparation of palladium using the Mound Muddy Water process

    Energy Technology Data Exchange (ETDEWEB)

    Baldwin, D.P.; Zamzow, D.S.

    1998-11-10

    Palladium used at Savannah River for tritium storage is currently obtained from a commercial source. In order to better understand the processes involved in preparing this material, Savannah River is supporting investigations into the chemical reactions used to synthesize this material and into the conditions necessary to produce palladium powder that meets their specifications. This better understanding may help to guarantee a continued reliable source for this material in the future. As part of this evaluation, a work-for-others contract between Westinghouse Savannah River Company and the Ames Laboratory Metallurgy and Ceramics Program was initiated. During FY98, the process for producing palladium powder developed in 1986 by Dan Grove of Mound Applied Technologies (USDOE) was studied to understand the processing conditions that lead to changes in morphology in the final product. This report details the results of this study of the Mound Muddy Water process, along with the results of a round-robin analysis of well-characterized palladium samples that was performed by Savannah River and Ames Laboratory. The Mound Muddy Water process is comprised of three basic wet chemical processes, palladium dissolution, neutralization, and precipitation, with a number of filtration steps to remove unwanted impurity precipitates.

  14. Westinghouse Savannah River Company: Report from the DOE Voluntary Protection Program onsite reviews, February 24--March 7, 1997, and June 15--19, 1998

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-05-01

    This report summarizes the Department of Energy Voluntary Protection Program (DOE-VPP) Initial and Update Review Teams` findings from the onsite evaluations of the Westinghouse Savannah River Site (SRS), conducted February 24--March 7, 1997, and June 15-19, 1998. The site was evaluated against the program requirements contained in US Department of Energy Voluntary Protection Program, Part 1: Program Elements to determine its success in implementing the five tenets of DOE-VPP. The Initial Review Team concluded that WSRC met or surpassed all DOE-VPP requirements, with the exception of 12 minor findings and 5 recommendations. WSRC was asked to resolve the findings within 90 days. During a follow-up visit in January 1996, representatives of the Team verified that all 90-day actions were completed. The Update Team detected though that the program did not demonstrate thorough and meaningful employee involvement. The ability to attain and sustain VPP-level performance on employee involvement is a significant challenge. Large companies with multiple layers of management and geographically disperse personnel have particular difficulty.

  15. Smart parking barrier

    KAUST Repository

    Alharbi, Abdulrazaq M.

    2016-05-06

    Various methods and systems are provided for smart parking barriers. In one example, among others, a smart parking barrier system includes a movable parking barrier located at one end of a parking space, a barrier drive configured to control positioning of the movable parking barrier, and a parking controller configured to initiate movement of the parking barrier, via the barrier drive. The movable parking barrier can be positioned between a first position that restricts access to the parking space and a second position that allows access to the parking space. The parking controller can initiate movement of the movable parking barrier in response to a positive identification of an individual allowed to use the parking space. The parking controller can identify the individual through, e.g., a RFID tag, a mobile device (e.g., a remote control, smartphone, tablet, etc.), an access card, biometric information, or other appropriate identifier.

  16. Integrating planning and design optimization for thermal power generation in developing economies: Designs for Vietnam

    Science.gov (United States)

    Pham, John Dinh Chuong

    In the twenty first century, global warming and climate change have become environmental issues worldwide. There is a need to reduce greenhouse gas emissions from thermal power plants through improved efficiency. This need is shared by both developed and developing countries. It is particularly important in rapidly developing economies (for example, Vietnam, South Korea, and China) where there is very significant need to increase generation capacity. This thesis addresses improving thermal power plant efficiency through an improved planning process that emphasizes integrated design. With the integration of planning and design considerations of key components in thermal electrical generation, along with the selection of appropriate up-to-date technologies, greater efficiency and reduction of emissions could be achieved. The major barriers to the integration of overall power plant optimization are the practice of individual island tendering packages, and the lack of coordinating efforts between major original equipment manufacturers (OEM). This thesis assesses both operational and design aspects of thermal power plants to identify opportunities for energy saving and the associated reduction of CO2 emissions. To demonstrate the potential of the integrated planning design approach, three advanced thermal power plants, using anthracite coal, oil and gas as their respective fuel, were developed as a case study. The three plant formulations and simulations were performed with the cooperation of several leading companies in the power industry including Babcock & Wilcox, Siemens KWU, Siemens-Westinghouse Power Corporation, Hitachi, Alstom Air Preheater, TLT-Covent, and ABB Flakt. The first plant is a conventional W-Flame anthracite coal-fired unit for base load operation. The second is a supercritical oil-fired plant with advanced steam condition, for two shifting and cycling operations. The third plant is a gas-fired combined cycle unit employing a modern steam-cooled gas

  17. ASSESSING LONGITUDINAL THERMAL CONNECTIVITY ...

    Science.gov (United States)

    Water temperature is a key driver of ecological processes in aquatic environments and can influence biological connectivity among riverine habitats. Riverine fish and other mobile aquatic species often must navigate a variety of physical barriers such as dams and culverts. For Pacific salmon, warm water can also pose barriers to migration, but the presence of patches of cooler water within rivers can serve as important refuges and potentially as stepping stones at times of day when temperatures are elsewhere unsuitable along the migratory corridor. Rising water temperature associated with climate change has become a major conservation concern for freshwater species and poses challenges for natural resource managers who must consider multiple factors in addition to uncertainty in climate predictions. Thermal refuges can contribute to watershed-scale thermal resilience and are increasingly considered in water quality regulations; however, monitoring such refuges and effectively operationalizing the concept for management has proved difficult. We review what is known about use of thermal refuges by coldwater fishes in natural systems, and then we present two case study applications in which we characterize thermal patterns in rivers (e.g., the frequency, size, spacing, and location of thermal patches) and consider effects on salmon in a management context. In our first example, we illustrate methods for quantifying spatial heterogeneity in stream temperatures at bi

  18. Skin barrier function

    DEFF Research Database (Denmark)

    2016-01-01

    on the subject. It covers new basic research on skin markers, including results on filaggrin and on methods for the assessment of the barrier function. Biological variation and aspects of skin barrier function restoration are discussed as well. Further sections are dedicated to clinical implications of skin...... barrier integrity, factors influencing the penetration of the skin, influence of wet work, and guidance for prevention and saving the barrier. Distinguished researchers have contributed to this book, providing a comprehensive and thorough overview of the skin barrier function. Researchers in the field...

  19. Tunnel barrier schottky

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Rongming; Cao, Yu; Li, Zijian; Williams, Adam J.

    2018-02-20

    A diode includes: a semiconductor substrate; a cathode metal layer contacting a bottom of the substrate; a semiconductor drift layer on the substrate; a graded aluminum gallium nitride (AlGaN) semiconductor barrier layer on the drift layer and having a larger bandgap than the drift layer, the barrier layer having a top surface and a bottom surface between the drift layer and the top surface, the barrier layer having an increasing aluminum composition from the bottom surface to the top surface; and an anode metal layer directly contacting the top surface of the barrier layer.

  20. Westinghouse Accident Tolerant Fuel Program

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Peng [Westinghouse Electric Corp., Columbia, SC (United States)

    2013-08-21

    The PowerPoint presentation includes a timeline for the program implementation, the technical approach taken, a summary of testing results, a status of task 2, what has been done to share the results so far, and a summary of upcoming work.

  1. Thermal stress fracture of ceramic coatings

    Science.gov (United States)

    Andersson, C. A.

    1983-01-01

    Thermal stress failures of ceramic coatings are discussed in terms of fracture mechanics concepts. The effects of transient and residual stresses on single and multiple cycle failure mechanisms are considered. A specific example of a zirconia thermal barrier coating is presented and its endurance calculated using the proposed relationships.

  2. Transforming Education: Overcoming Barriers.

    Science.gov (United States)

    David, Jane L.; Goren, Paul D.

    Barriers to progress in educational reform exist inside and outside the education system. Some arise where new practices encounter traditional expectations and boundaries, but others go much deeper than education, such as poverty, racism, local political conflicts, and human resistance to change. The following five categories of barriers are…

  3. Penetration resistant barrier

    Science.gov (United States)

    Hoover, William R.; Mead, Keith E.; Street, Henry K.

    1977-01-01

    The disclosure relates to a barrier for resisting penetration by such as hand tools and oxy-acetylene cutting torches. The barrier comprises a layer of firebrick, which is preferably epoxy impregnated sandwiched between inner and outer layers of steel. Between the firebrick and steel are layers of resilient rubber-like filler.

  4. Complementary Barrier Infrared Detector

    Science.gov (United States)

    Ting, David Z.; Bandara, Sumith V.; Hill, Cory J.; Gunapala, Sarath D.

    2009-01-01

    The complementary barrier infrared detector (CBIRD) is designed to eliminate the major dark current sources in the superlattice infrared detector. The concept can also be applied to bulk semiconductor- based infrared detectors. CBIRD uses two different types of specially designed barriers: an electron barrier that blocks electrons but not holes, and a hole barrier that blocks holes but not electrons. The CBIRD structure consists of an n-contact, a hole barrier, an absorber, an electron barrier, and a p-contact. The barriers are placed at the contact-absorber junctions where, in a conventional p-i-n detector structure, there normally are depletion regions that produce generation-recombination (GR) dark currents due to Shockley-Read- Hall (SRH) processes. The wider-bandgap complementary barriers suppress G-R dark current. The barriers also block diffusion dark currents generated in the diffusion wings in the neutral regions. In addition, the wider gap barriers serve to reduce tunneling dark currents. In the case of a superlattice-based absorber, the superlattice itself can be designed to suppress dark currents due to Auger processes. At the same time, the barriers actually help to enhance the collection of photo-generated carriers by deflecting the photo-carriers that are diffusing in the wrong direction (i.e., away from collectors) and redirecting them toward the collecting contacts. The contact layers are made from materials with narrower bandgaps than the barriers. This allows good ohmic contacts to be made, resulting in lower contact resistances. Previously, THALES Research and Technology (France) demonstrated detectors with bulk InAsSb (specifically InAs0.91Sb0.09) absorber lattice-matched to GaSb substrates. The absorber is surrounded by two wider bandgap layers designed to minimize impedance to photocurrent flow. The wide bandgap materials also serve as contacts. The cutoff wavelength of the InAsSb absorber is fixed. CBIRD may be considered as a modified

  5. Ion assisted growth of B4C diffusion barrier layers in Mo/Si multilayered structures

    NARCIS (Netherlands)

    Bruijn, S.; Bruijn, S.; van de Kruijs, Robbert Wilhelmus Elisabeth; Yakshin, Andrey; Bijkerk, Frederik

    2012-01-01

    We investigated the thermal stability of e-beam deposited Mo/B 4C/Si/B 4C layered systems, with and without ion assistance during the growth of the B 4C diffusion barrier layers. The thermal stability was investigated by in situ thermal annealing during grazing incidence X-ray reflection. By

  6. Geochemical barriers for environment protection and recovery of nonferrous metals.

    Science.gov (United States)

    Chanturiya, Valentine; Masloboev, Vladimir; Makarov, Dmitriy; Nesterov, Dmitriy; Bajurova, Julia; Svetlov, Anton; Men'shikov, Yuriy

    2014-01-01

    A study of natural minerals, ore tailings and their products as materials for artificial geochemical barriers is presented. In particular, it focuses on interaction between calcite and dolomite and sulfate solutions containing nickel, copper and iron under static conditions. Calcite of -0.1 mm fraction has been shown to perform well as a barrier when added to water phases of tailing dumps and natural reservoirs. Experiments under dynamic conditions have revealed a high potential of thermally activated copper-nickel tailings as barriers. After a 500-day precipitating period on a geochemical barrier, the contents of nickel and copper in ore dressing tailings were found to increase 12- and 28-fold, respectively. An effective sorbent of copper, iron and nickel ions is a brucite-based product of hydrochloric acid treatment of vermiculite ore tailings. Its sorption capacity can be essentially increased through thermal activation.

  7. Thermal comfort

    CSIR Research Space (South Africa)

    Osburn, L

    2010-01-01

    Full Text Available wider range of temperature limits, saving energy while still satisfying the majority of building occupants. It is also noted that thermal comfort varies significantly between individuals and it is generally not possible to provide a thermal environment...

  8. Converse Barrier Certificate Theorems

    DEFF Research Database (Denmark)

    Wisniewski, Rafael; Sloth, Christoffer

    2016-01-01

    This paper shows that a barrier certificate exists for any safe dynamical system. Specifically, we prove converse barrier certificate theorems for a class of structurally stable dynamical systems. Other authors have developed a related result by assuming that the dynamical system has neither...... singular points nor closed orbits. In this paper, we redefine the standard notion of safety to comply with dynamical systems with multiple singular elements. Hereafter, we prove the converse barrier certificate theorems and highlight the differences between our results and previous work by a number...

  9. Converse Barrier Certificate Theorem

    DEFF Research Database (Denmark)

    Wisniewski, Rafael; Sloth, Christoffer

    2013-01-01

    This paper presents a converse barrier certificate theorem for a generic dynamical system.We show that a barrier certificate exists for any safe dynamical system defined on a compact manifold. Other authors have developed a related result, by assuming that the dynamical system has no singular...... points in the considered subset of the state space. In this paper, we redefine the standard notion of safety to comply with generic dynamical systems with multiple singularities. Afterwards, we prove the converse barrier certificate theorem and illustrate the differences between ours and previous work...

  10. Recycler barrier RF buckets

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, C.M.; /Fermilab

    2011-03-01

    The Recycler Ring at Fermilab uses a barrier rf systems for all of its rf manipulations. In this paper, I will give an overview of historical perspective on barrier rf system, the longitudinal beam dynamics issues, aspects of rf linearization to produce long flat bunches and methods used for emittance measurements of the beam in the RR barrier rf buckets. Current rf manipulation schemes used for antiproton beam stacking and longitudinal momentum mining of the RR beam for the Tevatron collider operation are explained along with their importance in spectacular success of the Tevatron luminosity performance.

  11. Applications of dielectric barrier discharges

    Energy Technology Data Exchange (ETDEWEB)

    Falkenstein, Z.

    1998-12-01

    Dielectric barrier discharges (DBDs) in oxygen and air are well established for the production of large quantities of ozone and are more recently being applied to a wider range of plasmachemical processes. As an introduction of this type of gas discharge, the main plasmaphysical features of sinusoidal-driven DBDs (transient, non-thermal plasmas at atmospheric pressure) will be described, and plasmachemical reaction pathways for the generation of ozone will be briefly discussed. The generation of atomic oxygen for ozone synthesis leads inevitably to the second application of DBDs, the non-thermal oxidation of volatile organic compounds (VOCs) in dry and humid air. Another application of DBDs is the generation of excited dimers and exiplexes for the production of incoherent (V)UV/visible light. The last and latest application of DBDs is the surface processing near atmospheric pressures. As an example, results of photoresist ashing on Si wafers in an oxygen plasma will be shown as function of gas pressure, gap spacing, and applied frequency. The surface of the etched photoresist is characterized by profilometry and scanning electron microscopy (SEM). The possibility of material deposition with DBDs will also be presented, where DBDs in acetylene lead to fast substrate deposition. Here, only the effects of the gas pressure and gap distance are explored.

  12. California highway barrier aesthetics

    Science.gov (United States)

    2002-06-01

    This report will familiarize designers with current barrier design options, and encourage appropriate aesthetic considerations to develop visually pleasing context sensitive solutions for highway projects. Technical guidelines allow integral color, p...

  13. Thermal stability of quaternary alloy (InAlGaAs)-capped InAs/GaAs multilayer quantum dot heterostructures with variation in growth rate, barrier thickness, seed quantum dot monolayer coverage, and post-growth annealing

    Energy Technology Data Exchange (ETDEWEB)

    Mandal, A.; Chakrabarti, S. [Indian Institute of Technology Bombay, Department of Electrical Engineering, Mumbai, Maharashtra (India); Verma, U. [Indian Institute of Technology Rajasthan, Department of Electrical Engineering, Jodhpur, Rajasthan (India)

    2013-10-15

    Strain-driven influences on the structural and optoelectronic properties of self-assembled InAs/GaAs multilayer quantum dot (MQD) heterostructures prompted our research into the growth of thermally stable MQD samples that were functional in an emission range technically favorable for communication lasers and intermediate band gap solar cells. We also studied parameter optimization by varying growth rate, capping layer thickness, seed quantum dot (QD) monolayer coverage, and post-growth annealing. A capping combination of InAlGaAs and i-GaAs was used. This combination helps in strain compensation, favors growth of multiple QD layers, functions as a strain-driven phase separation alloy, and helps increase QD stability. Photoluminescence results showed MQD sample emissions in the technologically significant range of 1.1-1.3 {mu}m. Post-growth annealing at high temperatures led to inter-diffusion of the constituent QD materials, generation of low minimum energy states, and greater carrier involvement in intermediate band gap structures, thereby showing that annealing is a suitable method for post-growth manipulation. For one MQD sample, the annealing temperature was found to affect structural and optoelectronic properties as well as the presence of intermediate energy states. Heterostructure stability at annealing temperatures up to 750 {sup circle} C was found for the other samples. Transmission electron microscopy and photoluminescence results supported these findings. (orig.)

  14. Permeation barrier for lightweight liquid hydrogen tanks

    Energy Technology Data Exchange (ETDEWEB)

    Schultheiss, D.

    2007-04-16

    For the future usage of hydrogen as an automotive fuel, its on-board storage is crucial. One approach is the storage of liquid hydrogen (LH2, 20 K) in double-walled, vacuum insulated tanks. The introduction of carbon fiber reinforced plastics (CFRP) as structural material enables a high potential of reducing the weight in comparison to the state-of-the-art stainless steel tanks. The generally high permeability of hydrogen through plastics, however, can lead to long-term degradation of the insulating vacuum. The derived objective of this dissertation was to find and apply an adequate permeation barrier (liner) on CFRP. The investigated liners were either foils adhered on CFRP specimens or coatings deposited on CFRP specimens. The coatings were produced by means of thermal spraying, metal plating or physical vapor deposition (PVD). The materials of the liners included Al, Au, Cu, Ni and Sn as well as stainless steel and diamond-like carbon. The produced liners were tested for their permeation behavior, thermal shock resistance and adherence to the CFRP substrate. Additionally, SEM micrographs were used to characterize and qualify the liners. The foils, although being a good permeation barrier, adhered weakly to the substrate. Furthermore, leak-free joining of foil segments is a challenge still to be solved. The metal plating liners exhibited the best properties. For instance, no permeation could be detected through a 50 {mu}m thick Cu coating within the accuracy of the measuring apparatus. This corresponds to a reduction of the permeation gas flow by more than factor 7400 compared to uncoated CFRP. In addition, the metal platings revealed a high adherence and thermal shock resistance. The coatings produced by means of thermal spraying and PVD did not show a sufficient permeation barrier effect. After having investigated the specimens, a 170 liter CFRP tank was fully coated with 50 {mu}m Cu by means of metal plating. (orig.)

  15. Thermally stable diamond brazing

    Science.gov (United States)

    Radtke, Robert P [Kingwood, TX

    2009-02-10

    A cutting element and a method for forming a cutting element is described and shown. The cutting element includes a substrate, a TSP diamond layer, a metal interlayer between the substrate and the diamond layer, and a braze joint securing the diamond layer to the substrate. The thickness of the metal interlayer is determined according to a formula. The formula takes into account the thickness and modulus of elasticity of the metal interlayer and the thickness of the TSP diamond. This prevents the use of a too thin or too thick metal interlayer. A metal interlayer that is too thin is not capable of absorbing enough energy to prevent the TSP diamond from fracturing. A metal interlayer that is too thick may allow the TSP diamond to fracture by reason of bending stress. A coating may be provided between the TSP diamond layer and the metal interlayer. This coating serves as a thermal barrier and to control residual thermal stress.

  16. Conduction heat transfer in a cylindrical dielectric barrier discharge reactor

    Energy Technology Data Exchange (ETDEWEB)

    Sadat, H. [Laboratoire d' Etudes Thermiques, Universite de Poitiers, 40 Avenue du Recteur Pineau, 86022 Poitiers (France)], E-mail: hamou.sadat@univ-poitiers.fr; Dubus, N. [Laboratoire d' Etudes Thermiques, Universite de Poitiers, 40 Avenue du Recteur Pineau, 86022 Poitiers (France); Pinard, L.; Tatibouet, J.M.; Barrault, J. [Laboratoire en catalyse et chimie organique, Universite de Poitiers, 40 Avenue du Recteur Pineau, 86022 Poitiers (France)

    2009-04-15

    The thermal behaviour of a dielectric barrier discharge reactor is studied. The experimental tests are performed on a laboratory reactor with two working fluids: helium and air. A simple heat conduction model for calculating the heat loss is developed. By using temperature measurements in the internal and external electrodes, a thermal resistance of the reactor is defined. Finally, the percentage of the input power that is dissipated to the environment is given.

  17. Hedging Double Barriers with Singles

    NARCIS (Netherlands)

    Sbuelz, A.

    2000-01-01

    Double barrier options provide risk managers with good-deal flexibility in tailoring portfolio returns.Their hedges offer full protection only if unwound along the barriers.This work provides non-dynamic hedges that project the risk of double barriers on to single barriers.Non-dynamic hedges

  18. Significant advantages of the safety-first concept in construction, operation, and maintenance of the Westinghosue AP1000 reactor; Signifikante Vorteile des Safety-First-Konzeptes bei Errichtung, Betrieb und Wartung des Westinghouse AP1000-Reaktors

    Energy Technology Data Exchange (ETDEWEB)

    Cummins, E. [Westinghosue Electric Co., Pittsburgh (United States); Benitz, K. [Westinghouse Electric Co., Mannheim (Germany)

    2004-02-01

    In June 2003, the U.S. Nuclear Regulatory Commission (USNRC) published a draft opinion about safety of the AP1000 Westinghouse pressurized water reactor with 'passive safety' features. The report constitutes an important milestone in the development of the next generation of safe and cost-efficient nuclear power plants. A new AP1000 can be absolutely competitive with fossil fired power plants and may be able to revive the construction of new nuclear power plants worldwide. The reason for designing the AP1000 were safety considerations. The use of passive safety systems at the same time entails a considerable reduction in the costs of design, maintenance, and operation of an AP1000 plant. Independent experts confirmed that an AP1000 can be erected within three years or even less. The estimated electricity generating costs of an AP1000 plant in the United States amount to US Cent 3.2 to 3.6 per kilowatthour. (orig.)

  19. Barriers to effective teaching.

    Science.gov (United States)

    DaRosa, Debra A; Skeff, Kelley; Friedland, Joan A; Coburn, Michael; Cox, Susan; Pollart, Susan; O'connell, Mark; Smith, Sandy

    2011-04-01

    Medical school faculty members are charged with the critical responsibility of preparing the future physician and medical scientist workforce. Recent reports suggest that medical school curricula have not kept pace with societal needs and that medical schools are graduating students who lack the knowledge and skills needed to practice effectively in the 21st century. The majority of faculty members want to be effective teachers and graduate well-prepared medical students, but multiple and complex factors-curricular, cultural, environmental, and financial-impede their efforts. Curricular impediments to effective teaching include unclear definitions of and disagreement on learning needs, misunderstood or unstated goals and objectives, and curriculum sequencing challenges. Student and faculty attitudes, too few faculty development opportunities, and the lack of an award system for teaching all are major culture-based barriers. Environmental barriers, such as time limitations, the setting, and the physical space in which medical education takes place, and financial barriers, such as limited education budgets, also pose serious challenges to even the most committed teachers. This article delineates the barriers to effective teaching as noted in the literature and recommends action items, some of which are incremental whereas others represent major change. Physicians-in-training, medical faculty, and society are depending on medical education leaders to address these barriers to effect the changes needed to enhance teaching and learning. © by the Association of American Medical Colleges.

  20. Skin barrier in rosacea*

    Science.gov (United States)

    Addor, Flavia Alvim Sant'Anna

    2016-01-01

    Recent studies about the cutaneous barrier demonstrated consistent evidence that the stratum corneum is a metabolically active structure and also has adaptive functions, may play a regulatory role in the inflammatory response with activation of keratinocytes, angiogenesis and fibroplasia, whose intensity depends primarily on the intensity the stimulus. There are few studies investigating the abnormalities of the skin barrier in rosacea, but the existing data already show that there are changes resulting from inflammation, which can generate a vicious circle caused a prolongation of flare-ups and worsening of symptoms. This article aims to gather the most relevant literature data about the characteristics and effects of the state of the skin barrier in rosacea. PMID:26982780

  1. Health Barriers to Learning

    Directory of Open Access Journals (Sweden)

    Delaney Gracy

    2014-01-01

    Full Text Available This article summarizes the results from a 2013 online survey with 408 principals and assistant principals in New York City public elementary and middle schools. The survey assessed three primary areas: health issues in the school, health issues perceived as barriers to learning for affected students, and resources needed to address these barriers. Eighteen of the 22 health conditions listed in the survey were considered a moderate or serious issue within their schools by at least 10% of respondents. All 22 of the health issues were perceived as a barrier to learning by between 12% and 87% of the respondents. Representatives from schools that serve a higher percentage of low-income students reported significantly higher levels of concern about the extent of health issues and their impact on learning. Respondents most often said they need linkages with organizations that can provide additional services and resources at the school, especially for mental health.

  2. A study of magnetic and spectroscopic properties of Fe(II)Fe(III)2O(CH3CO2)6L3, L=H2O or C5H5N. Direct observation of the thermal barrier to electron transfer in a mixed valence complex

    Science.gov (United States)

    Dziobkowski, C. T.; Wrobleski, J. T.; Brown, D. B.

    1980-10-01

    The mixed-valence iron (2, 3, 3) acetates, (Fe3O(CH3CO2)6L3), where L = water or pyridine, have been prepared and studied by Mossbauer, infrared, and optical spectroscopy and magnetic susceptibility methods. Variable-temperature magnetic susceptibility data for the aquo complex are interpreted on the basis of HDVV S2 = 2, S1 = S3 = 5/2 spin exchange model with J12 = j23 = 1/-50 cm and J13 = 1/14.5 cm. An intervalence transfer band is observed at 1/138000 cm in the room temperature electronic spectrum of the aquo complex. Mossbauer spectra of these compounds are markedly temperature dependent. At 17K absorptions due to distinct Fe(2) and Fe(3) sites are observed while at 300 K a single absorption is observed. Spectra at intermediate temperatures are modeled by assuming intratrimer electronic relaxation between pairs of iron ions. The activation energy for relaxation derived from this model is 1/470 cm for the aquo complex. This energy is equal to the barrier to intramolecular, intervalence thermal electron transfer.

  3. Barrier distributions and scattering

    Energy Technology Data Exchange (ETDEWEB)

    Timmers, H.; Leigh, J.R.; Dasgupta, M.; Hinde, D.J.; Mein, J.C.; Morton, C.R.; Newton, J.O. [Department of Nuclear Physics, Australian National University, Canberra, ACT 0200 (Austria); Rowley, N. [Centre de Recherches Nucleaires, 23 Rue du Loess, F-67037 Strasbourg CEDEX 2 (France); Stefanini, A.M.; Ackermann, D.; Corradi, L.; He, J.H. [INFN, Laboratori Nazionali di Legnaro, Legnaro (PD) (Italy); Beghini, S.; Montagnoli, G.; Scarlassara, F.; Segato, G.F. [Universita di Padova and INFN Sezione di Padova, Padova (Italy)

    1997-10-01

    The extraction of representations of the fusion barrier distribution from backward-angle, quasi-elastic, elastic and transfer excitation functions is discussed. Such excitation functions have been measured for {sup 16}O, {sup 32}S and {sup 40}Ca projectiles incident on a variety of targets. The results are compared with representations obtained from fusion excitation functions. Varying in their sensitivity, all representations show evidence of the barrier structure. Differences between the scattering and the fusion representations can be related to the effects of coupling to residual, weak reaction channels. (author)

  4. Carrier Transfer between InGaAs/GaAs Quantum Wells Separated by Thick Barriers

    DEFF Research Database (Denmark)

    Borri, Paola; Gurioli, M.; Colocci, M.

    1997-01-01

    We have studied the carrier transfer between two adjacent wells of different width separated by a 100 nm thick barrier. At low temperatures (T 30 K: the transfer strongly increases, denoting that the thermal escape out of the QW...

  5. Applications of dielectric barrier discharges

    Energy Technology Data Exchange (ETDEWEB)

    Falkenstein, Z.

    1998-12-31

    Dielectric barrier discharges (DBDs) in oxygen and air are well established for the production of large quantities of ozone and are more recently being applied to a wider range of plasmachemical processes. Here, the application of DBDs for ozone synthesis, the non-thermal oxidation of volatile organic compounds (VOCs) in air, the generation of incoherent (V)UV radiation and surface processing (etching, ashing) is presented. The main plasmaphysical features of sinusoidally-driven DBDs (transient, filamented, non-thermal plasmas at atmospheric pressure) are described, and a simple plasmachemical reaction pathway for ozone synthesis are give. Experimental results on the degradation of VOCs (2-propanol, trichloroethylene, carbon tetrachloride), as well as byproduct formation is presented for stand-alone DBD treatment, as well as for simultaneous (V)UV illumination of the discharge. Illumination of the discharge with (V)UV can change the plasmachemistry by enhanced formation of certain species of radicals--and thereby change byproduct formation--but also can change the discharge physics, known as the Joshi effect. As an example for generation of excited dimers and exiplexes for the production of incoherent UV light, experimental results on a XeBr* excimer UV light source are presented. Effects of the total and partial pressure of a Xe/Br{sub 2} system, the gap spacing and the applied driving frequency on the UV radiant efficiency are shown. For the application of DBDs for surface processing, experimental results of photoresist ashing on Si wafers using DBDs in oxygen are shown function of gas pressure, gap spacing and applied frequency.

  6. Great Barrier Reef

    Science.gov (United States)

    2002-01-01

    A better than average view of the Great Barrier Reef was captured by SeaWiFS on a recent overpass. There is sunglint northeast of the reef and there appears to be some sort of filamentous bloom in the Capricorn Channel.

  7. Support or Barrier?

    DEFF Research Database (Denmark)

    Sanden, Guro Refsum; Lønsmann, Dorte

    This study offers a critical look at how corporate-level language management influences front-line language practices among employees in three multinational corporations (MNCs) headquartered in Scandinavia. Based on interview and document data, we examine, firstly, what front-line practices emplo...... to a discussion of how a company’s language policy may be seen as both support and a barrier....

  8. Thermal-hydraulic modeling needs for passive reactors

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, J.M. [Nuclear Regulatory Commission, Washington, DC (United States)

    1997-07-01

    The U.S. Nuclear Regulatory Commission has received an application for design certification from the Westinghouse Electric Corporation for an Advanced Light Water Reactor design known as the AP600. As part of the design certification process, the USNRC uses its thermal-hydraulic system analysis codes to independently audit the vendor calculations. The focus of this effort has been the small break LOCA transients that rely upon the passive safety features of the design to depressurize the primary system sufficiently so that gravity driven injection can provide a stable source for long term cooling. Of course, large break LOCAs have also been considered, but as the involved phenomena do not appear to be appreciably different from those of current plants, they were not discussed in this paper. Although the SBLOCA scenario does not appear to threaten core coolability - indeed, heatup is not even expected to occur - there have been concerns as to the performance of the passive safety systems. For example, the passive systems drive flows with small heads, consequently requiring more precision in the analysis compared to active systems methods for passive plants as compared to current plants with active systems. For the analysis of SBLOCAs and operating transients, the USNRC uses the RELAP5 thermal-hydraulic system analysis code. To assure the applicability of RELAP5 to the analysis of these transients for the AP600 design, a four year long program of code development and assessment has been undertaken.

  9. Thermal-Hydraulic Analysis Tasks for ANAV NPPs in Support of Plant Operation and Control

    Directory of Open Access Journals (Sweden)

    L. Batet

    2007-11-01

    Full Text Available Thermal-hydraulic analysis tasks aimed at supporting plant operation and control of nuclear power plants are an important issue for the Asociación Nuclear Ascó-Vandellòs (ANAV. ANAV is the consortium that runs the Ascó power plants (2 units and the Vandellòs-II power plant. The reactors are Westinghouse-design, 3-loop PWRs with an approximate electrical power of 1000 MW. The Technical University of Catalonia (UPC thermal-hydraulic analysis team has jointly worked together with ANAV engineers at different levels in the analysis and improvement of these reactors. This article is an illustration of the usefulness of computational analysis for operational support. The contents presented were operational between 1985 and 2001 and subsequently changed slightly following various organizational adjustments. The paper has two different parts. In the first part, it describes the specific aspects of thermal-hydraulic analysis tasks related to operation and control and, in the second part, it briefly presents the results of three examples of analyses that were performed. All the presented examples are related to actual situations in which the scenarios were studied by analysts using thermal-hydraulic codes and prepared nodalizations. The paper also includes a qualitative evaluation of the benefits obtained by ANAV through thermal-hydraulic analyses aimed at supporting operation and plant control.

  10. Penetration through the Skin Barrier

    DEFF Research Database (Denmark)

    Nielsen, Jesper Bo; Benfeldt, Eva; Holmgaard, Rikke

    2016-01-01

    and exogenous factors may affect barrier characteristics. The present chapter introduces the theory for barrier penetration (Fick's law), and describes and discusses different methods for measuring the kinetics of percutaneous penetration of chemicals, including in vitro methods (static and flow...

  11. Apoplastic Diffusion Barriers in Arabidopsis

    Science.gov (United States)

    Schreiber, Lukas; Franke, Rochus Benni; Geldner, Niko; Reina-Pinto, José J.; Kunst, Ljerka

    2013-01-01

    During the development of Arabidopsis and other land plants, diffusion barriers are formed in the apoplast of specialized tissues within a variety of plant organs. While the cuticle of the epidermis is the primary diffusion barrier in the shoot, the Casparian strips and suberin lamellae of the endodermis and the periderm represent the diffusion barriers in the root. Different classes of molecules contribute to the formation of extracellular diffusion barriers in an organ- and tissue-specific manner. Cutin and wax are the major components of the cuticle, lignin forms the early Casparian strip, and suberin is deposited in the stage II endodermis and the periderm. The current status of our understanding of the relationships between the chemical structure, ultrastructure and physiological functions of plant diffusion barriers is discussed. Specific aspects of the synthesis of diffusion barrier components and protocols that can be used for the assessment of barrier function and important barrier properties are also presented. PMID:24465172

  12. Enabling fast charging - Battery thermal considerations

    Science.gov (United States)

    Keyser, Matthew; Pesaran, Ahmad; Li, Qibo; Santhanagopalan, Shriram; Smith, Kandler; Wood, Eric; Ahmed, Shabbir; Bloom, Ira; Dufek, Eric; Shirk, Matthew; Meintz, Andrew; Kreuzer, Cory; Michelbacher, Christopher; Burnham, Andrew; Stephens, Thomas; Francfort, James; Carlson, Barney; Zhang, Jiucai; Vijayagopal, Ram; Hardy, Keith; Dias, Fernando; Mohanpurkar, Manish; Scoffield, Don; Jansen, Andrew N.; Tanim, Tanvir; Markel, Anthony

    2017-11-01

    Battery thermal barriers are reviewed with regards to extreme fast charging. Present-day thermal management systems for battery electric vehicles are inadequate in limiting the maximum temperature rise of the battery during extreme fast charging. If the battery thermal management system is not designed correctly, the temperature of the cells could reach abuse temperatures and potentially send the cells into thermal runaway. Furthermore, the cell and battery interconnect design needs to be improved to meet the lifetime expectations of the consumer. Each of these aspects is explored and addressed as well as outlining where the heat is generated in a cell, the efficiencies of power and energy cells, and what type of battery thermal management solutions are available in today's market. Thermal management is not a limiting condition with regard to extreme fast charging, but many factors need to be addressed especially for future high specific energy density cells to meet U.S. Department of Energy cost and volume goals.

  13. and use of barrier techniques

    African Journals Online (AJOL)

    consistent use of barrier techniques. Key-words: Attitudes, Dentists, Hepatitis B vaccination,. Barrier techniques. Résumé. Objectif: Virus Hépatite B constitue une menace importante pour le bien ... vacination contre hépatite B ct l'utilisation des techniques do la barriere. .... to staff and rarely from dentist to patients However,.

  14. Can-Filled Crash Barrier

    Science.gov (United States)

    Wilson, A. H.

    1983-01-01

    Crash barrier composed largely of used aluminum beverage cans protects occupants of cars in collisions with poles or trees. Lightweight, can-filled barrier very effective in softening impact of an automobile in head-on and off-angle collisions. Preliminary results indicate barrier is effective in collisions up to 40 mi/h (64 km/h).

  15. [The cultural barrier in care].

    Science.gov (United States)

    Djadaoudjee, Lisa

    2013-11-01

    French cultural diversity is evident within French hospitals, where nurses are confronted with communication problems resulting from the language barrier. While communication is indeed essential, there is another important aspect of caring for a patient for behind the language barrier lies a cultural barrier which must be taken into account in order to provide high-quality care.

  16. Thermal Barrier Coatings (les Revetements anti-mur de chaleur)

    Science.gov (United States)

    1998-04-01

    Coatings (les Revetements anti-mur de chaleur ) U:.j> ^ST^K^NT A Papers presented at the 85th Meeting of the AGARD Structures and Materials Panel...nations in aerospace research and development; — Exchange of scientific and technical information; — Providing assistance to member nations for the...Panels which are composed of experts appointed by the National Delegates, the Consultant and Exchange Programme and the Aerospace Applications Studies

  17. Comparative study on effect of blending, thermal barrier coating (LHR)

    African Journals Online (AJOL)

    DR OKE

    adiabatic will enhance the overall engine performance. ..... inlet cooling water temperature of 80°C. A piezoelectric pressure transducer was mounted ..... The differences between saturated and unsaturated fatty acids of vegetable oils play an ...

  18. Barriers for recess physical activity

    DEFF Research Database (Denmark)

    Pawlowski, Charlotte Skau; Tjørnhøj-Thomsen, Tine; Schipperijn, Jasper

    2014-01-01

    differences in children's perceptions of barriers to recess physical activity. Based on the socio-ecological model four types of environmental barriers were distinguished: natural, social, physical and organizational environment. METHODS: Data were collected through 17 focus groups (at 17 different schools......BACKGROUND: Many children, in particular girls, do not reach the recommended amount of daily physical activity. School recess provides an opportunity for both boys and girls to be physically active, but barriers to recess physical activity are not well understood. This study explores gender...... and girls identified the same barriers, there were both inter- and intra-gender differences in the perception of these barriers. Weather was a barrier for all children, apart from the most active boys. Conflicts were perceived as a barrier particularly by those boys who played ballgames. Girls said...

  19. Barrier mechanisms in the Drosophila blood-brain barrier

    Directory of Open Access Journals (Sweden)

    Samantha Jane Hindle

    2014-12-01

    Full Text Available The invertebrate blood-brain barrier field is growing at a rapid pace and, in recent years, studies have shown a physiologic and molecular complexity that has begun to rival its vertebrate counterpart. Novel mechanisms of paracellular barrier maintenance through GPCR signaling were the first demonstrations of the complex adaptive mechanisms of barrier physiology. Building upon this work, the integrity of the invertebrate blood-brain barrier has recently been shown to require coordinated function of all layers of the compound barrier structure, analogous to signaling between the layers of the vertebrate neurovascular unit. These findings strengthen the notion that many blood-brain barrier mechanisms are conserved between vertebrates and invertebrates, and suggest that novel findings in invertebrate model organisms will have a significant impact on the understanding of vertebrate BBB functions. In this vein, important roles in coordinating localized and systemic signaling to dictate organism development and growth are beginning to show how the blood-brain barrier can govern whole animal physiologies. This includes novel functions of blood-brain barrier gap junctions in orchestrating synchronized neuroblast proliferation, and of blood-brain barrier secreted antagonists of insulin receptor signaling. These advancements and others are pushing the field forward in exciting new directions. In this review, we provide a synopsis of invertebrate blood-brain barrier anatomy and physiology, with a focus on insights from the past 5 years, and highlight important areas for future study.

  20. Thermal comfort

    DEFF Research Database (Denmark)

    d’Ambrosio Alfano, Francesca Romana; Olesen, Bjarne W.; Palella, Boris Igor

    2014-01-01

    Thermal comfort is one of the most important aspects of the indoor environmental quality due to its effects on well-being, people's performance and building energy requirements. Its attainment is not an easy task requiring advanced design and operation of building and HVAC systems, taking...... under specific conditions. At operation level, only few variables are taken into account with unpredictable effects on the assessment of comfort indices. In this paper, the main criteria for the design and assessment of thermal comfort are discussed in order to help building and HVAC systems designers...... into account all parameters involved. Even though thermal comfort fundamentals are consolidated topics for more than forty years, often designers seem to ignore or apply them in a wrong way. Design input values from standards are often considered as universal values rather than recommended values to be used...

  1. [Barrier methods of contraception].

    Science.gov (United States)

    Goldsmith, A; Edelman, D A

    1982-01-01

    Vaginal methods of contraception were the earliest types used and some references to them date back to antiquity. Most of the vaginal contraceptive agents identified by the ancient Greeks, Indians, Japanese, and Chinese have been found in modern laboratory tests to have spermicidal properties, but it is doubtful that the methods were fully reliable or were used by many people. During the 19th century the condom, vaginal spermicides, and diaphragm became available. The development of nonoxynol-9 and other nonirritating but effective spermicidal agents improved vaginal contraceptives greatly by the 1950s, but starting in the 1960s newer methods began to replace the vaginal methods. Interest in barrier methods has been reawakened somewhat by concern about the health effects of hormonal methods. At present all barrier methods leave something to be desired. Failure rates of 3-30% for barrier methods in general have been estimated, but the higher rates are believed due to incorrect or inconsistent use. Theoretical failure rates of condoms and diaphragms have been estimated at 3/100 women-years, but in actual use failure rates may reach 15 for condoms and 13 for diaphragms used with spermicides. Use-effectiveness rates are greatly influenced by motivation. For a variety of reasons, the acceptability of barrier methods is low, especially in developing countries. New developments in spermicidal agents include sperm inhibitors, which impede the fertilizing capacity of sperm rather than attempting a spermicidal effect; a number of such agents have been studied and have proven more effective in animal tests than conventional spermicides. Neosampoon, a new spermicidal foam, has attracted an increasing number of users, especially in developing countries. A new condom, made of thin polymers and containing a standard dose of nonoxynol-9, has been designed to dissolve in the vaginal fluid. Further studies are needed of its acceptability, efficacy, and side effects before it becomes

  2. Thermally Actuated Hydraulic Pumps

    Science.gov (United States)

    Jones, Jack; Ross, Ronald; Chao, Yi

    2008-01-01

    Thermally actuated hydraulic pumps have been proposed for diverse applications in which direct electrical or mechanical actuation is undesirable and the relative slowness of thermal actuation can be tolerated. The proposed pumps would not contain any sliding (wearing) parts in their compressors and, hence, could have long operational lifetimes. The basic principle of a pump according to the proposal is to utilize the thermal expansion and contraction of a wax or other phase-change material in contact with a hydraulic fluid in a rigid chamber. Heating the chamber and its contents from below to above the melting temperature of the phase-change material would cause the material to expand significantly, thus causing a substantial increase in hydraulic pressure and/or a substantial displacement of hydraulic fluid out of the chamber. Similarly, cooling the chamber and its contents from above to below the melting temperature of the phase-change material would cause the material to contract significantly, thus causing a substantial decrease in hydraulic pressure and/or a substantial displacement of hydraulic fluid into the chamber. The displacement of the hydraulic fluid could be used to drive a piston. The figure illustrates a simple example of a hydraulic jack driven by a thermally actuated hydraulic pump. The pump chamber would be a cylinder containing encapsulated wax pellets and containing radial fins to facilitate transfer of heat to and from the wax. The plastic encapsulation would serve as an oil/wax barrier and the remaining interior space could be filled with hydraulic oil. A filter would retain the encapsulated wax particles in the pump chamber while allowing the hydraulic oil to flow into and out of the chamber. In one important class of potential applications, thermally actuated hydraulic pumps, exploiting vertical ocean temperature gradients for heating and cooling as needed, would be used to vary hydraulic pressures to control buoyancy in undersea research

  3. Laser cooling of fast stored ions in barrier buckets

    CERN Document Server

    Eisenbarth, U; Grieser, M; Grimm, R; Lauer, I; Lenisa, P; Luger, V; Mudrich, M; Schätz, T; Schramm, U; Schwalm, D; Weidemüller, M

    2000-01-01

    We apply novel bunch forms for efficient laser cooling of fast stored ion beams at the Heidelberg Test Storage Ring. sup 9 Be sup + ions are longitudinally confined in barrier buckets providing free motion of the cooled ions inside the bucket (quasi-coasting beam). The implementation of laser cooling in barrier buckets is described, and longitudinal dynamics of laser cooling is compared to electron cooling. With laser cooling, longitudinal temperatures far below 1 K are reached, corresponding to a momentum spread of DELTA p/p<10 sup - sup 6. When the thermal energy becomes sufficiently small, significant modifications of the ion distribution due to space-charge effects are observed.

  4. Melt Focusing Along Permeability Barriers in Various Tectonic Settings

    Science.gov (United States)

    Montesi, L. G.; Hebert, L. B.

    2012-12-01

    The lithosphere, cold and rigid, acts as a barrier to the migration of melt from sources in the convecting mantle to the surface. In mid-ocean ridge settings in particular, the contrast between the width of the melt production zone at depths, reaching tens to hundreds of kilometer from the ridge axis, and the zone of crustal accretion, only one or two kilometers wide, points to the presence of an efficient focusing mechanism. The development of a zone impermeable to melt, or permeability barrier, at the base of the thermal boundary layer, and transport of melt in a high porosity channel at the base of this barrier provides a reasonable explanation for this focusing. Applied to various segmented and non-segmented mid-ocean ridges like the ultraslow Southwest Indian Ridge and the ultrafast East Pacific Rise at the Siqueiros transform, this process predicts along-strike variations in crustal thickness that compare favorably with observations. Although the concept of permeability barriers has been discussed mainly in the context of mid-ocean ridges, it may apply to other locations where melting in the upper mantle occurs. Permeability barriers form when ascending melt cools and crystallizes as it enters the thermal boundary layer at the base of the lithosphere. Such a setup is present at subduction zones as melts ascending from the mantle wedge interact with the overriding plate. Convection in the wedge introduces thermal gradients that may focus melt roughly to a point above the transition from a coupled to decoupled slab interface. This location is close to where volcanic arcs are observed. Above mantle plumes, a permeability barrier may develop coincident with the lithosphere-asthenosphere boundary, allowing low-degree melts to stall and form a low-velocity layer that has been observed seismically. To date, the hypothesis of a permeability barrier has been thoroughly tested only in the context of mid-ocean ridges. Whether crystallization would be rapid enough in

  5. International Collaboration Activities on Engineered Barrier Systems

    Energy Technology Data Exchange (ETDEWEB)

    Jove-Colon, Carlos F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-08-31

    The Used Fuel Disposition Campaign (UFDC) within the DOE Fuel Cycle Technologies (FCT) program has been engaging in international collaborations between repository R&D programs for high-level waste (HLW) disposal to leverage on gathered knowledge and laboratory/field data of near- and far-field processes from experiments at underground research laboratories (URL). Heater test experiments at URLs provide a unique opportunity to mimetically study the thermal effects of heat-generating nuclear waste in subsurface repository environments. Various configurations of these experiments have been carried out at various URLs according to the disposal design concepts of the hosting country repository program. The FEBEX (Full-scale Engineered Barrier Experiment in Crystalline Host Rock) project is a large-scale heater test experiment originated by the Spanish radioactive waste management agency (Empresa Nacional de Residuos Radiactivos S.A. – ENRESA) at the Grimsel Test Site (GTS) URL in Switzerland. The project was subsequently managed by CIEMAT. FEBEX-DP is a concerted effort of various international partners working on the evaluation of sensor data and characterization of samples obtained during the course of this field test and subsequent dismantling. The main purpose of these field-scale experiments is to evaluate feasibility for creation of an engineered barrier system (EBS) with a horizontal configuration according to the Spanish concept of deep geological disposal of high-level radioactive waste in crystalline rock. Another key aspect of this project is to improve the knowledge of coupled processes such as thermal-hydro-mechanical (THM) and thermal-hydro-chemical (THC) operating in the near-field environment. The focus of these is on model development and validation of predictions through model implementation in computational tools to simulate coupled THM and THC processes.

  6. Engineered Barrier System: Physical and Chemical Environment

    Energy Technology Data Exchange (ETDEWEB)

    P. Dixon

    2004-04-26

    The conceptual and predictive models documented in this Engineered Barrier System: Physical and Chemical Environment Model report describe the evolution of the physical and chemical conditions within the waste emplacement drifts of the repository. The modeling approaches and model output data will be used in the total system performance assessment (TSPA-LA) to assess the performance of the engineered barrier system and the waste form. These models evaluate the range of potential water compositions within the emplacement drifts, resulting from the interaction of introduced materials and minerals in dust with water seeping into the drifts and with aqueous solutions forming by deliquescence of dust (as influenced by atmospheric conditions), and from thermal-hydrological-chemical (THC) processes in the drift. These models also consider the uncertainty and variability in water chemistry inside the drift and the compositions of introduced materials within the drift. This report develops and documents a set of process- and abstraction-level models that constitute the engineered barrier system: physical and chemical environment model. Where possible, these models use information directly from other process model reports as input, which promotes integration among process models used for total system performance assessment. Specific tasks and activities of modeling the physical and chemical environment are included in the technical work plan ''Technical Work Plan for: In-Drift Geochemistry Modeling'' (BSC 2004 [DIRS 166519]). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system analysis model reports.

  7. Thermal defoliation

    Science.gov (United States)

    The negative perception some consumers hold regarding agricultural chemicals has resulted in an increased demand for organic foods and fibers, and in increasing political pressure for the regulation of agricultural production practices. This has revived interest in thermal defoliation of cotton and ...

  8. Holographic thermalization

    NARCIS (Netherlands)

    Balasubramanian, V.; Bernamonti, A.; de Boer, J.; Copland, N.; Craps, B.; Keski-Vakkuri, E.; Müller, B.; Schäfer, A.; Shigemori, M.; Staessens, W.

    2011-01-01

    Using the AdS/CFT correspondence, we probe the scale-dependence of thermalization in strongly coupled field theories following a quench, via calculations of two-point functions, Wilson loops and entanglement entropy in d=2,3,4. In the saddlepoint approximation these probes are computed in AdS space

  9. Thermal and combined thermal and radiolytic reactions involving nitrous oxide, hydrogen, nitrogen, and ammonia in contact with tank 241-SY-101 simulated waste

    Energy Technology Data Exchange (ETDEWEB)

    Bryan, S.A.; Pederson, L.R.

    1996-02-01

    Work described in this report was conducted at Pacific Northwest National Laboratory (PNNL) for the Flammable Gas Safety Project, the purpose of which is to develop information needed to support Westinghouse Hanford Company (WHC) in their efforts to ensure the safe interim storage of wastes at the Hanford Site. Described in this report are the results of tests to evaluate the rates of thermal and combined thermal and radiolytic reactions involving flammable gases in the presence of Tank 241-SY-101 simulated waste. Flammable gases generated by the radiolysis of water and by the thermal and radiolytic decomposition of organic waste constituents may themselves participate in further reactions. Examples include the decomposition of nitrous oxide to yield nitrogen and oxygen, the reaction of nitrous oxide and hydrogen to produce nitrogen and water, and the reaction of nitrogen and hydrogen to produce ammonia. The composition of the gases trapped in bubbles in the wastes might therefore change continuously as a function of the time that the gas bubbles are retained.

  10. Thermal Hardware for the Thermal Analyst

    Science.gov (United States)

    Steinfeld, David

    2015-01-01

    The presentation will be given at the 26th Annual Thermal Fluids Analysis Workshop (TFAWS 2015) hosted by the Goddard Space Flight Center (GSFC) Thermal Engineering Branch (Code 545). NCTS 21070-1. Most Thermal analysts do not have a good background into the hardware which thermally controls the spacecraft they design. SINDA and Thermal Desktop models are nice, but knowing how this applies to the actual thermal hardware (heaters, thermostats, thermistors, MLI blanketing, optical coatings, etc...) is just as important. The course will delve into the thermal hardware and their application techniques on actual spacecraft. Knowledge of how thermal hardware is used and applied will make a thermal analyst a better engineer.

  11. Ocean barrier layers' effect on tropical cyclone intensification.

    Science.gov (United States)

    Balaguru, Karthik; Chang, Ping; Saravanan, R; Leung, L Ruby; Xu, Zhao; Li, Mingkui; Hsieh, Jen-Shan

    2012-09-04

    Improving a tropical cyclone's forecast and mitigating its destructive potential requires knowledge of various environmental factors that influence the cyclone's path and intensity. Herein, using a combination of observations and model simulations, we systematically demonstrate that tropical cyclone intensification is significantly affected by salinity-induced barrier layers, which are "quasi-permanent" features in the upper tropical oceans. When tropical cyclones pass over regions with barrier layers, the increased stratification and stability within the layer reduce storm-induced vertical mixing and sea surface temperature cooling. This causes an increase in enthalpy flux from the ocean to the atmosphere and, consequently, an intensification of tropical cyclones. On average, the tropical cyclone intensification rate is nearly 50% higher over regions with barrier layers, compared to regions without. Our finding, which underscores the importance of observing not only the upper-ocean thermal structure but also the salinity structure in deep tropical barrier layer regions, may be a key to more skillful predictions of tropical cyclone intensities through improved ocean state estimates and simulations of barrier layer processes. As the hydrological cycle responds to global warming, any associated changes in the barrier layer distribution must be considered in projecting future tropical cyclone activity.

  12. Ocean Barrier Layers’ Effect on Tropical Cyclone Intensification

    Energy Technology Data Exchange (ETDEWEB)

    Balaguru, Karthik; Chang, P.; Saravanan, R.; Leung, Lai-Yung R.; Xu, Zhao; Li, M.; Hsieh, J.

    2012-09-04

    Improving a tropical cyclone's forecast and mitigating its destructive potential requires knowledge of various environmental factors that influence the cyclone's path and intensity. Herein, using a combination of observations and model simulations, we systematically demonstrate that tropical cyclone intensification is significantly affected by salinity-induced barrier layers, which are 'quasi-permanent' features in the upper tropical oceans. When tropical cyclones pass over regions with barrier layers, the increased stratification and stability within the layer reduce storm-induced vertical mixing and sea surface temperature cooling. This causes an increase in enthalpy flux from the ocean to the atmosphere and, consequently, an intensification of tropical cyclones. On average, the tropical cyclone intensification rate is nearly 50% higher over regions with barrier layers, compared to regions without. Our finding, which underscores the importance of observing not only the upper-ocean thermal structure but also the salinity structure in deep tropical barrier layer regions, may be a key to more skillful predictions of tropical cyclone intensities through improved ocean state estimates and simulations of barrier layer processes. As the hydrological cycle responds to global warming, any associated changes in the barrier layer distribution must be considered in projecting future tropical cyclone activity.

  13. Countermeasures and barriers

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Johannes [Oersted - DTU, Automation, Kgs. Lyngby (Denmark)

    2005-10-01

    In 1973 Haddon proposed ten strategies for reducing and avoiding damages based on a model of potential harmful energy transfer (Haddon, 1973). The strategies apply to a large variety of unwanted phenomena. Haddon's pioneering work on countermeasures has had a major influence on later thinking about safety. Considering its impact it is remarkable that the literature offers almost no discussions related to the theoretical foundations of Haddon's countermeasure strategies. The present report addresses a number of theoretical issues related to Haddon's countermeasure strategies, which are: 1) A reformulation and formalization of Haddon's countermeasure strategies. 2) An identification and description of some of the problems associated with the term 'barrier'. 3) Suggestions for a more precise terminology based on the causal structure of countermeasures. 4) Extending the scope of countermeasures to include sign-based countermeasures. (au)

  14. Smoldering and Flame Resistant Textiles via Conformal Barrier Formation.

    Science.gov (United States)

    Zammarano, Mauro; Cazzetta, Valeria; Nazaré, Shonali; Shields, J Randy; Kim, Yeon Seok; Hoffman, Kathleen M; Maffezzoli, Alfonso; Davis, Rick

    2016-12-07

    A durable and flexible silicone-based backcoating (halogen free) is applied to the backside of an otherwise smoldering-prone and flammable fabric. When exposed to fire, cyclic siloxanes (produced by thermal decomposition of the backcoating) diffuse through the fabric in the gas phase. The following oxidation of the cyclic siloxanes forms a highly conformal and thermally stable coating that fully embeds all individual fibers and shields them from heat and oxidation. As a result, the combustion of the fabric is prevented. This is a novel fire retardant mechanism that discloses a powerful approach towards textiles and multifunctional flexible materials with combined smoldering/flaming ignition resistance and fire-barrier properties.

  15. Nuclear Thermal Rocket - An Established Space Propulsion Technology

    Science.gov (United States)

    Klein, Milton

    2004-02-01

    From the late 1950s to the early 1970s a major program successfully developed the capability to conduct space exploration using the advanced technology of nuclear rocket propulsion. The program had two primary elements: pioneering and advanced technology work-Rover-at Los Alamos National Laboratory and its contractors provided the basic reactor design, fuel materials development, and reactor testing capability; and engine development-NERVA-by the industrial team of Aerojet and Westinghouse building on and extending the Los Alamos efforts to flight system development. This presentation describes the NERVA program, the engine system testing that demonstrated the space-practical operation capabilities of nuclear thermal rockets, and the mission studies that point the way to most effectively use the NTR capabilities. Together, the two programs established a technology base that includes proven NTR capabilities of (1) over twice the specific impulse of chemical propulsion systems, (2) thrust capabilities ranging from 44kN to 1112kN, and (3) practical thrust-to-weight ratios for future NASA space exploration missions, both manned payloads to Mars and unmanned payloads to the outer planets. The overall nuclear rocket program had a unique management structure that integrated the efforts of the two government agencies involved-NASA and the then-existing Atomic Energy Commission. The objective of this paper is to summarize and convey the technical and management lessons learned in this program as the nation considers the design of its future space exploration activities.

  16. Thermal Clothing

    Science.gov (United States)

    1997-01-01

    Gateway Technologies, Inc. is marketing and developing textile insulation technology originally developed by Triangle Research and Development Corporation. The enhanced thermal insulation stems from Small Business Innovation Research contracts from NASA's Johnson Space Center and the U.S. Air Force. The effectiveness of the insulation comes from the microencapsulated phase-change materials originally made to keep astronauts gloved hands warm. The applications for the product range from outer wear, housing insulation, and blankets to protective firefighting gear and scuba diving suits. Gateway has developed and begun marketing thermal regulating products under the trademark, OUTLAST. Products made from OUTLAST are already on the market, including boot and shoe liners, winter headgear, hats and caps for hunting and other outdoor sports, and a variety of men's and women's ski gloves.

  17. Turbulent Thermalization

    CERN Document Server

    Micha, Raphael; Micha, Raphael; Tkachev, Igor I.

    2004-01-01

    We study, analytically and with lattice simulations, the decay of coherent field oscillations and the subsequent thermalization of the resulting stochastic classical wave-field. The problem of reheating of the Universe after inflation constitutes our prime motivation and application of the results. We identify three different stages of these processes. During the initial stage of ``parametric resonance'', only a small fraction of the initial inflaton energy is transferred to fluctuations in the physically relevant case of sufficiently large couplings. A major fraction is transfered in the prompt regime of driven turbulence. The subsequent long stage of thermalization classifies as free turbulence. During the turbulent stages, the evolution of particle distribution functions is self-similar. We show that wave kinetic theory successfully describes the late stages of our lattice calculation. Our analytical results are general and give estimates of reheating time and temperature in terms of coupling constants and...

  18. 24 CFR 3280.207 - Requirements for foam plastic thermal insulating materials.

    Science.gov (United States)

    2010-04-01

    ... mineral fiber insulation or an equivalent thermal barrier; or (3) The foam plastic insulating material has... thermal insulating materials. 3280.207 Section 3280.207 Housing and Urban Development Regulations Relating... SAFETY STANDARDS Fire Safety § 3280.207 Requirements for foam plastic thermal insulating materials. (a...

  19. Actin filaments growing against a barrier with fluctuating shape.

    Science.gov (United States)

    Sadhu, Raj Kumar; Chatterjee, Sakuntala

    2016-06-01

    We study force generation by a set of parallel actin filaments growing against a nonrigid obstacle, in the presence of an external load. The filaments polymerize by either moving the whole obstacle, with a large energy cost, or by causing local distortion in its shape which costs much less energy. The nonrigid obstacle also has local thermal fluctuations due to which its shape can change with time and we describe this using fluctuations in the height profile of a one-dimensional interface with Kardar-Parisi-Zhang dynamics. We find the shape fluctuations of the barrier strongly affect the force generation mechanism. The qualitative nature of the force-velocity curve is crucially determined by the relative time scale of filament and barrier dynamics. The height profile of the barrier also shows interesting variation with the external load. Our analytical calculations within mean-field theory show reasonable agreement with our simulation results.

  20. BARRIERS OF STRATEGIC ALLIANCES ORGANIZATION

    Directory of Open Access Journals (Sweden)

    Vladislav M. Sannikov

    2014-01-01

    Full Text Available General barriers of organization of different types of strategic alliances have beenconsidered in the article. There are several recommendations for overcoming themin cases of international alliances, and in case of work in one state. The article also identified goals and tasks of single coordination center of alliance to overcome organization barriers.

  1. Epistemological barriers to radical behaviorism.

    Science.gov (United States)

    O'Donohue, W T; Callaghan, G M; Ruckstuhl, L E

    1998-01-01

    The historian and philosopher of science Gaston Bachelard proposed the concept of epistemological barriers to describe the intellectual challenges encountered by scientists in their work. In order to embrace novel ways of approaching a problem in science, scientists must overcome barriers or obstacles posed by their prior views. For example, Einsteinian physics presents scientists with claims that space is curved and that time and space are on the same continuum. We utilize Bachelard's concept of epistemological barriers to describe the differences between the intellectual journeys students pursuing advanced studies face when attempting to accept cognitive psychology or radical behaviorism. We contend that the folk psychological beliefs that students typically hold when entering these studies pose less challenge to cognitive psychology than to radical behaviorism. We also suggest that these barriers may also partly be involved in the problematic exegesis that has plagued radical behaviorism. In close, we offer some suggestions for dealing with these epistemological barriers.

  2. Electrical insulator assembly with oxygen permeation barrier

    Science.gov (United States)

    Van Der Beck, Roland R.; Bond, James A.

    1994-01-01

    A high-voltage electrical insulator (21) for electrically insulating a thermoelectric module (17) in a spacecraft from a niobium-1% zirconium alloy wall (11) of a heat exchanger (13) filled with liquid lithium (16) while providing good thermal conductivity between the heat exchanger and the thermoelectric module. The insulator (21) has a single crystal alumina layer (SxAl.sub.2 O.sub.3, sapphire) with a niobium foil layer (32) bonded thereto on the surface of the alumina crystal (26) facing the heat exchanger wall (11), and a molybdenum layer (31) bonded to the niobium layer (32) to act as an oxygen permeation barrier to preclude the oxygen depleting effects of the lithium from causing undesirable niobium-aluminum intermetallic layers near the alumina-niobium interface.

  3. Heat transport of graphene-based normal metal-ferromagnetic barrier-superconductor junctions

    Science.gov (United States)

    Zargar Shoushtari, M.; Hajati, Y.; Jafari Zadeh, B.

    2014-12-01

    In this paper, the effect of ferromagnetic barrier (FB) on the thermal conductance of graphene-based normal metal/ferromagnetic barrier/s- and d-wave superconductor junction has been studied theoretically. The results show that the exchange energy (h) in the ferromagnetic barrier has a strong effect on the amplitude, phase and period of the thermal conductance oscillations in terms of the FB length. Also, we have discussed novel thermal conductance oscillations in a graphene-based NFBS junction that happened for maximum superconducting orientation α=π/4. This finding is arisen from the quantum nature of interference between spin states, up and down quasiparticles in FB region. Interestingly, at α=π/4 the h has also the highest effect on the thermal conductance and by increasing the exchange energy h, the thermal conductance enhances at this angle. The exchange energy h also affects the thermal conductance as a function of temperature for both s- and d-wave superconductor. At last, we propose an experimental setup to detect our predicted effects.

  4. Thermal insulator

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, R.; Asada, Y.; Matsuo, Y.; Mikoda, M.

    1985-07-16

    A thermal insulator comprises an expanded resin body having embedded therein an evacuated powder insulation portion which consists of fine powder and a container of film-like plastics or a film-like composite of plastics and metal for enclosing the powder. The resin body has been expanded by a Freon gas as a blowing agent. Since a Freon gas has a larger molecular diameter than the constituent gases of air, it is less likely to permeate through the container than air. Thus present invention provides a novel composite insulator which fully utilizes the benefits of vacuum insulation without necessitating a strong and costly material for a vacuum container.

  5. Barriers to organic milk production

    Directory of Open Access Journals (Sweden)

    Jiří Duda

    2012-01-01

    Full Text Available This paper describes barriers to production of the organic milk. There was conducted a survey among conventional producers of cow’s milk. Based on the identified barriers to organic milk production and farmers’ opinions on them there were identified the most important barriers. The most important barrier to the production of organic milk in Vysočina region is considered to be the lack of price premiums for organic milk produced. The price premium is currently around 0.40 CZK per litre of organic milk. Farmers require a minimum price premium 1 CZK per litre, respectively 30 % increase of the price of milk. The higher price premium may serve as a motivation, which could eliminate the second major barrier - satisfaction with the current production. Problematic contact with suppliers has been identified as the third most important barrier by surveyed firms. Buyers do not respect the agreed purchase price (premium price. Partial barrier to organic milk production, according to surveyed farmers is the lack of the necessary amount of concentrated feed in the quality of organic milk.

  6. A composite vacuum barrier for the LHC short straight section

    Energy Technology Data Exchange (ETDEWEB)

    Jenny, B.; Rohmig, P. [CERN, Geneva (Switzerland); Uriarte, J.M. [FIBERTECNIC, Vitoria-Gasteiz (Spain)

    1996-12-31

    The lattice of the CERN Large Hadron Collider (LHC) will contain 384 Short Straight Section (SSS) units, one in every 53 m half-cell. The SSS is composed of a twin aperture high-field superconducting quadrupole and of two combined-function corrector magnets operating in pressurized helium at 1.9 K. The SSS cryostat contains also a barrier for sectorisation of the insulation vacuum. The vacuum barrier is mounted between the helium vessel and the vacuum enclosure. Its functions are to limit the extent of eventual helium leaks and to facilitate the leak detection and the pumping-down from atmospheric pressure. During installation of the LHC, the vacuum barrier permits independent testing of the half-cells, thus enabling higher installation rates. In parallel to a conventional barrier made out of austenitic stainless steel, a barrier of composite material was developed, taking advantage of the lower thermal conductivity of glass fibre reinforced epoxy resin, and with the aim of reducing costs for LHC. The thermo-mechanical design together with the conception and the moulding techniques used for the manufacture of the prototype are described. Bonding techniques for the leak tight stainless steel composite interfaces are presented and test results shown. Results on the mechanical performance and on the helium tests carried out on the prototype are given.

  7. Australia's Great Barrier Reef

    Science.gov (United States)

    2001-01-01

    The Great Barrier Reef extends for 2,000 kilometers along the northeastern coast of Australia. It is not a single reef, but a vast maze of reefs, passages, and coral cays (islands that are part of the reef). This nadir true-color image was acquired by the MISR instrument on August 26, 2000 (Terra orbit 3679), and shows part of the southern portion of the reef adjacent to the central Queensland coast. The width of the MISR swath is approximately 380 kilometers, with the reef clearly visible up to approximately 200 kilometers from the coast. It may be difficult to see the myriad details in the browse image, but if you retrieve the higher resolution version, a zoomed display reveals the spectacular structure of the many reefs.The more northerly coastal area in this image shows the vast extent of sugar cane cultivation, this being the largest sugar producing area in Australia, centered on the city of Mackay. Other industries in the area include coal, cattle, dairying, timber, grain, seafood, and fruit. The large island off the most northerly part of the coast visible in this image is Whitsunday Island, with smaller islands and reefs extending southeast, parallel to the coast. These include some of the better known resort islands such as Hayman, Lindeman, Hamilton, and Brampton Islands.Further south, just inland of the small semicircular bay near the right of the image, is Rockhampton, the largest city along the central Queensland coast, and the regional center for much of central Queensland. Rockhampton is just north of the Tropic of Capricorn. Its hinterland is a rich pastoral, agricultural, and mining region.MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

  8. Nature of "superluminal" barrier tunneling.

    Science.gov (United States)

    Winful, Herbert G

    2003-01-17

    We show that the distortionless tunneling of electromagnetic pulses through a barrier is a quasistatic process in which the slowly varying envelope of the incident pulse modulates the amplitude of a standing wave. For pulses longer than the barrier width, the barrier acts as a lumped element with respect to the pulse envelope. The envelopes of the transmitted and reflected fields can adiabatically follow the incident pulse with only a small delay that originates from energy storage. The theory presented here provides a physical explanation of the tunneling process and resolves the mystery of apparent superluminality.

  9. Complexing-precipitating geochemical barriers

    Science.gov (United States)

    Savenko, A. V.

    2017-02-01

    New types of geochemical barriers on which chemical elements are immobilized as a result of combined complex formation and precipitation of barely soluble mineral phases are examined. A significant concentration of major components (Fe, Al) forming more stable complexes than an immobilized component X in the material is a necessary condition for this type of geochemical barriers. Filtration of the solution through a geochemical barrier is accompanied by substitution of X in the complex with a major component. As a result, the activity of X in the free state increases, and one barely soluble mineral phase or another of the component X precipitates when the state of saturation is achieved.

  10. Skin Barrier Function and Allergens

    DEFF Research Database (Denmark)

    Engebretsen, Kristiane Aasen; Thyssen, Jacob Pontoppidan

    2016-01-01

    The skin is an important barrier protecting us from mechanical insults, microorganisms, chemicals and allergens, but, importantly, also reducing water loss. A common hallmark for many dermatoses is a compromised skin barrier function, and one could suspect an elevated risk of contact sensitization...... and skin barrier status. Psoriasis has traditionally been regarded a Th1-dominated disease, but the discovery of Th17 cells and IL-17 provides new and interesting information regarding the pathogenesis of the disease. Research suggests an inverse relationship between psoriasis and CA, possibly due...

  11. Translating barriers into potential improvements

    DEFF Research Database (Denmark)

    Altintzoglou, Themistoklis; Hansen, Karina Birch; Valsdottir, Thora

    2010-01-01

    Purpose: The aim of this study is to explore potential barriers to seafood consumption by The aim of this study is to explore potential barriers to seafood consumption by young adults and the parents of young children. Knowledge of these barriers will be used to assist the development of new...... about the amount of effort required to prepare it. These concerns resulted in an expression of their need for products that are attractive, healthy, palatable, and convenient. In particular, the newly developed products should be accompanied by clear advice on preparation methods and materials...

  12. The Cementitious Barriers Partnership (CBP) Software Toolbox Capabilities in Assessing the Degradation of Cementitious Barriers - 13487

    Energy Technology Data Exchange (ETDEWEB)

    Flach, G.P.; Burns, H.H.; Langton, C.; Smith, F.G. III [Savannah River National Laboratory, Savannah River Site, Aiken SC 29808 (United States); Brown, K.G.; Kosson, D.S.; Garrabrants, A.C.; Sarkar, S. [Vanderbilt University, Nashville, TN (United States); Van der Sloot, H. [Hans Van der Sloot Consultancy (Netherlands); Meeussen, J.C.L. [Nuclear Research and Consultancy Group, Petten (Netherlands); Samson, E. [SIMCO Technologies Inc., 1400, boul. du Parc-Technologique, Suite 203, Quebec (Canada); Mallick, P.; Suttora, L. [United States Department of Energy, 1000 Independence Ave. SW, Washington, DC (United States); Esh, D.W.; Fuhrmann, M.J.; Philip, J. [U.S. Nuclear Regulatory Commission, Washington, DC (United States)

    2013-07-01

    The Cementitious Barriers Partnership (CBP) Project is a multi-disciplinary, multi-institutional collaboration supported by the U.S. Department of Energy (US DOE) Office of Tank Waste and Nuclear Materials Management. The CBP program has developed a set of integrated tools (based on state-of-the-art models and leaching test methods) that help improve understanding and predictions of the long-term structural, hydraulic and chemical performance of cementitious barriers used in nuclear applications. Tools selected for and developed under this program have been used to evaluate and predict the behavior of cementitious barriers used in near-surface engineered waste disposal systems for periods of performance up to 100 years and longer for operating facilities and longer than 1000 years for waste disposal. The CBP Software Toolbox has produced tangible benefits to the DOE Performance Assessment (PA) community. A review of prior DOE PAs has provided a list of potential opportunities for improving cementitious barrier performance predictions through the use of the CBP software tools. These opportunities include: 1) impact of atmospheric exposure to concrete and grout before closure, such as accelerated slag and Tc-99 oxidation, 2) prediction of changes in K{sub d}/mobility as a function of time that result from changing pH and redox conditions, 3) concrete degradation from rebar corrosion due to carbonation, 4) early age cracking from drying and/or thermal shrinkage and 5) degradation due to sulfate attack. The CBP has already had opportunity to provide near-term, tangible support to ongoing DOE-EM PAs such as the Savannah River Saltstone Disposal Facility (SDF) by providing a sulfate attack analysis that predicts the extent and damage that sulfate ingress will have on the concrete vaults over extended time (i.e., > 1000 years). This analysis is one of the many technical opportunities in cementitious barrier performance that can be addressed by the DOE-EM sponsored CBP

  13. The Cementitious Barriers Partnership (CBP) Software Toolbox Capabilities In Assessing The Degradation Of Cementitious Barriers

    Energy Technology Data Exchange (ETDEWEB)

    Flach, G. P. [Savannah River Site (SRS), Aiken, SC (United States); Burns, H. H. [Savannah River Site (SRS), Aiken, SC (United States); Langton, C. [Savannah River Site (SRS), Aiken, SC (United States); Smith, F. G. III [Savannah River Site (SRS), Aiken, SC (United States); Brown, K. G. [Vanderbilt University, Nashville, TN (United States); Kosson, D. S. [Vanderbilt University, Nashville, TN (United States); Garrabrants, A. C. [Vanderbilt University, Nashville, TN (United States); Sarkar, S. [Vanderbilt University, Nashville, TN (United States); van der Sloot, H. [Hans van der Sloot Consultancy (The Netherlands); Meeussen, J. C.L. [Nuclear Research and Consultancy Group, Petten (The Netherlands); Samson, E. [SIMCO Technologies Inc. , 1400, boul. du Parc - Technologique , Suite 203, Quebec (Canada); Mallick, P. [United States Department of Energy, 1000 Independence Ave. SW , Washington, DC (United States); Suttora, L. [United States Department of Energy, 1000 Independence Ave. SW , Washington, DC (United States); Esh, D. W. [U .S. Nuclear Regulatory Commission , Washington, DC (United States); Fuhrmann, M. J. [U .S. Nuclear Regulatory Commission , Washington, DC (United States); Philip, J. [U .S. Nuclear Regulatory Commission , Washington, DC (United States)

    2013-01-11

    The Cementitious Barriers Partnership (CBP) Project is a multi-disciplinary, multi-institutional collaboration supported by the U.S. Department of Energy (US DOE) Office of Tank Waste and Nuclear Materials Management. The CBP program has developed a set of integrated tools (based on state-of-the-art models and leaching test methods) that help improve understanding and predictions of the long-term structural, hydraulic and chemical performance of cementitious barriers used in nuclear applications. Tools selected for and developed under this program have been used to evaluate and predict the behavior of cementitious barriers used in near-surface engineered waste disposal systems for periods of performance up to 100 years and longer for operating facilities and longer than 1000 years for waste disposal. The CBP Software Toolbox has produced tangible benefits to the DOE Performance Assessment (PA) community. A review of prior DOE PAs has provided a list of potential opportunities for improving cementitious barrier performance predictions through the use of the CBP software tools. These opportunities include: 1) impact of atmospheric exposure to concrete and grout before closure, such as accelerated slag and Tc-99 oxidation, 2) prediction of changes in Kd/mobility as a function of time that result from changing pH and redox conditions, 3) concrete degradation from rebar corrosion due to carbonation, 4) early age cracking from drying and/or thermal shrinkage and 5) degradation due to sulfate attack. The CBP has already had opportunity to provide near-term, tangible support to ongoing DOE-EM PAs such as the Savannah River Saltstone Disposal Facility (SDF) by providing a sulfate attack analysis that predicts the extent and damage that sulfate ingress will have on the concrete vaults over extended time (i.e., > 1000 years). This analysis is one of the many technical opportunities in cementitious barrier performance that can be addressed by the DOE-EM sponsored CBP software

  14. Coastal Structures and Barriers 2012

    Data.gov (United States)

    California Department of Resources — This dataset is a compilation of the UCSC Sand Retention Structures, MC Barriers, and USACE Coastal Structures. UCSC Sand Retention Structures originate from a...

  15. Barrier creams: facts and controversies.

    Science.gov (United States)

    Corazza, Monica; Minghetti, Sara; Bianchi, Anna; Virgili, Annarosa; Borghi, Alessandro

    2014-01-01

    Barrier creams (BCs) represent devices aiming to protect the skin from contact with exogenous hazardous substances, especially under working conditions. By preventing penetration and absorption of contaminants, BCs are designed to reduce the risk of developing both irritant and allergic contact dermatitis. In fact, BCs should improve stratum corneum hydration as well as provide emolliency to maintain skin integrity and to restore and repair the epidermis barrier function. The formulation and ingredients of the available BCs vary widely, and thus the choice of a BC should depend on the kind of contaminants, occupational conditions, and skin dysfunction. Although BCs are commonly recommended to prevent occupational contact dermatitis, their real benefit remains controversial. The aims of this review are to help the choice of appropriate BCs and to analyze the actual effectiveness in maintaining an intact skin barrier, preventing contact dermatitis, and speeding up the healing of barrier-impaired skin.

  16. Novel hybrid polymeric materials for barrier coatings

    Science.gov (United States)

    Pavlacky, Erin Christine

    Polymer-clay nanocomposites, described as the inclusion of nanometer-sized layered silicates into polymeric materials, have been widely researched due to significant enhancements in material properties with the incorporation of small levels of filler (1--5 wt.%) compared to conventional micro- and macro-composites (20--30 wt.%). One of the most promising applications for polymer-clay nanocomposites is in the field of barrier coatings. The development of UV-curable polymer-clay nanocomposite barrier coatings was explored by employing a novel in situ preparation technique. Unsaturated polyesters were synthesized in the presence of organomodified clays by in situ intercalative polymerization to create highly dispersed clays in a precursor resin. The resulting clay-containing polyesters were crosslinked via UV-irradiation using donor-acceptor chemistry to create polymer-clay nanocomposites which exhibited significantly enhanced barrier properties compared to alternative clay dispersion techniques. The impact of the quaternary alkylammonium organic modifiers, used to increase compatibility between the inorganic clay and organic polymer, was studied to explore influence of the organic modifier structure on the nanocomposite material properties. By incorporating just the organic modifiers, no layered silicates, into the polyester resins, reductions in film mechanical and thermal properties were observed, a strong indicator of film plasticization. An alternative in situ preparation method was explored to further increase the dispersion of organomodified clay within the precursor polyester resins. In stark contrast to traditional in situ polymerization methods, a novel "reverse" in situ preparation method was developed, where unmodified montmorillonite clay was added during polyesterification to a reaction mixture containing the alkylammonium organic modifier. The resulting nanocomposite films exhibited reduced water vapor permeability and increased mechanical properties

  17. Great Barrier Reef, Queensland, Australia

    Science.gov (United States)

    1990-01-01

    This detailed view of the Great Barrier Reef, Queensland, Australia (19.5S, 149.5E) shows several small patch reefs within the overall reef system. The Great Barrier Reef, largest in the world, comprises thousands of individual reefs of great variety and are closely monitored by marine ecologists. These reefs are about 6000 years old and sit on top of much older reefs. The most rapid coral growth occurs on the landward side of the reefs.

  18. Superheavy nuclei and fission barriers

    Science.gov (United States)

    Lu, Bing-Nan; Zhao, Jie; Zhao, En-Guang; Zhou, Shan-Gui

    In this chapter, we will present relativistic mean field (RMF) description of heavy and superheavy nuclei (SHN). We will discuss the shell structure and magic numbers in the mass region of SHN, binding energies and α decay Q values, shapes of ground states and potential energy surfaces and fission barriers. We particularly focus on the multidimensionally-constrained covariant density functional theories (CDFT) and the applications of CDFT to the study of exotic nuclear shapes and fission barriers.

  19. Global interrupt and barrier networks

    Science.gov (United States)

    Blumrich, Matthias A.; Chen, Dong; Coteus, Paul W.; Gara, Alan G.; Giampapa, Mark E; Heidelberger, Philip; Kopcsay, Gerard V.; Steinmacher-Burow, Burkhard D.; Takken, Todd E.

    2008-10-28

    A system and method for generating global asynchronous signals in a computing structure. Particularly, a global interrupt and barrier network is implemented that implements logic for generating global interrupt and barrier signals for controlling global asynchronous operations performed by processing elements at selected processing nodes of a computing structure in accordance with a processing algorithm; and includes the physical interconnecting of the processing nodes for communicating the global interrupt and barrier signals to the elements via low-latency paths. The global asynchronous signals respectively initiate interrupt and barrier operations at the processing nodes at times selected for optimizing performance of the processing algorithms. In one embodiment, the global interrupt and barrier network is implemented in a scalable, massively parallel supercomputing device structure comprising a plurality of processing nodes interconnected by multiple independent networks, with each node including one or more processing elements for performing computation or communication activity as required when performing parallel algorithm operations. One multiple independent network includes a global tree network for enabling high-speed global tree communications among global tree network nodes or sub-trees thereof. The global interrupt and barrier network may operate in parallel with the global tree network for providing global asynchronous sideband signals.

  20. Economic alternatives for containment barriers

    Energy Technology Data Exchange (ETDEWEB)

    Nicholson, P.J.; Jasperse, B.H.; Fisher, M.J. [Geo-Con, Inc., Monroeville, PA (United States)

    1997-12-31

    Fixation, barriers, and containment of existing landfills and other disposal areas are often performed by insitu auger type soil mixing and jet grouting. Cement or other chemical reagents are mixed with soil to form both vertical and horizontal barriers. Immobilization of contaminants can be economically achieved by mixing soil and the contaminants with reagents that solidify or stabilize the contaminated area. Developed in Japan, and relatively new to the United States, the first large scale application was for a vertical barrier at the Jackson Lake Dam project in 1986. This technology has grown in both the civil and environmental field since. The paper describes current United States practice for Deep Soil Mixing (over 12 meters in depth), and Shallow Soil Mixing for vertical barriers and stabilization/solidification, and Jet Grouting for horizontal and vertical barriers. Creating very low permeability barriers at depth with minimal surface return often makes these techniques economical when compared to slurry trenches. The paper will discuss equipment, materials, soil and strength parameters, and quality control.

  1. Neurosurgical Techniques for Disruption of the Blood–Brain Barrier for Glioblastoma Treatment

    Directory of Open Access Journals (Sweden)

    Analiz Rodriguez

    2015-08-01

    Full Text Available The blood–brain barrier remains a main hurdle to drug delivery to the brain. The prognosis of glioblastoma remains grim despite current multimodal medical management. We review neurosurgical technologies that disrupt the blood–brain barrier (BBB. We will review superselective intra-arterial mannitol infusion, focused ultrasound, laser interstitial thermotherapy, and non-thermal irreversible electroporation (NTIRE. These technologies can lead to transient BBB and blood–brain tumor barrier disruption and allow for the potential of more effective local drug delivery. Animal studies and preliminary clinical trials show promise for achieving this goal.

  2. Magnetic Nanoparticles Cross the Blood-Brain Barrier: When Physics Rises to a Challenge

    Directory of Open Access Journals (Sweden)

    Maria Antònia Busquets

    2015-12-01

    Full Text Available The blood-brain barrier is a physical and physiological barrier that protects the brain from toxic substances within the bloodstream and helps maintain brain homeostasis. It also represents the main obstacle in the treatment of many diseases of the central nervous system. Among the different approaches employed to overcome this barrier, the use of nanoparticles as a tool to enhance delivery of therapeutic molecules to the brain is particularly promising. There is special interest in the use of magnetic nanoparticles, as their physical characteristics endow them with additional potentially useful properties. Following systemic administration, a magnetic field applied externally can mediate the capacity of magnetic nanoparticles to permeate the blood-brain barrier. Meanwhile, thermal energy released by magnetic nanoparticles under the influence of radiofrequency radiation can modulate blood-brain barrier integrity, increasing its permeability. In this review, we present the strategies that use magnetic nanoparticles, specifically iron oxide nanoparticles, to enhance drug delivery to the brain.

  3. Diabetes and diet : managing dietary barriers

    NARCIS (Netherlands)

    Friele, R.D.

    1989-01-01

    This thesis reports on the barriers diabetic patients experience with their diet, and the ways they cope with these barriers. A dietary barrier is a hinderance to a person's well-being, induced by being advised a diet. First inventories were made of possible dietary barriers and ways of

  4. Seasonal thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Allen, R.D.; Kannberg, L.D.; Raymond, J.R.

    1984-05-01

    This report describes the following: (1) the US Department of Energy Seasonal Thermal Energy Storage Program, (2) aquifer thermal energy storage technology, (3) alternative STES technology, (4) foreign studies in seasonal thermal energy storage, and (5) economic assessment.

  5. Fundamentals of Thermal Expansion and Thermal Contraction

    OpenAIRE

    Liu, Zi-Kui; Shang, Shun-Li; Wang, Yi

    2017-01-01

    Thermal expansion is an important property of substances. Its theoretical prediction has been challenging, particularly in cases the volume decreases with temperature, i.e., thermal contraction or negative thermal expansion at high temperatures. In this paper, a new theory recently developed by the authors has been reviewed and further examined in the framework of fundamental thermodynamics and statistical mechanics. Its applications to cerium with colossal thermal expansion and Fe3Pt with th...

  6. Ocean Thermal Energy Conversion power system development. Phase I: preliminary design. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1978-12-04

    Westinghouse has completed the Preliminary Design Phase for the Power System Development of the Ocean Thermal Energy Conversion (OTEC) Demonstration Plant project. This study included the development of a preliminary design for a Modular Application scaled power system (10MWe) and Heat Exchanger Test Articles, both based on the concept developed in the Conceptual Design Phase. The results of this study were used to improve the baseline design of the 50MWe module for the Commercial Size Power System, which was recommended for the demonstration plant by the conceptual design study. The 50MWe module was selected since it has the lowest cost, and since its size convincingly demonstrates that future economically viable commercial plants, having reliable operation with credible anticipated costs, are possible. Additional optimization studies on the size of the power system plus hull continue to identify 50MWe as the preferred minimum cost configuration. This study was limited to a closed cycle ammonia power system module, using a seawater temperature difference of 40/sup 0/F, and a surface platform/ship reference hull. This volume describes system operation, a complete test program to verify mechanical reliability and thermal performance, fabrication and installation operations, and a cost analysis. (WHK)

  7. Ocean Thermal Energy Conversion power system development. Phase I. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1978-12-04

    This report covers the conceptual and preliminary design of closed-cycle, ammonia, ocean thermal energy conversion power plants by Westinghouse Electric Corporation. Preliminary designs for evaporator and condenser test articles (0.13 MWe size) and a 10 MWe modular experiment power system are described. Conceptual designs for 50 MWe power systems, and 100 MWe power plants are also descirbed. Design and cost algorithms were developed, and an optimized power system design at the 50 MWe size was completed. This design was modeled very closely in the test articles and in the 10 MWe Modular Application. Major component and auxiliary system design, materials, biofouling, control response, availability, safety and cost aspects are developed with the greatest emphasis on the 10 MWe Modular Application Power System. It is concluded that all power plant subsystems are state-of-practice and require design verification only, rather than continued research. A complete test program, which verifies the mechanical reliability as well as thermal performance, is recommended and described.

  8. Thermal/chemical degradation of ceramic cross-flow filter materials

    Energy Technology Data Exchange (ETDEWEB)

    Alvin, M.A.; Lane, J.E.; Lippert, T.E.

    1989-11-01

    This report summarizes the 14-month, Phase 1 effort conducted by Westinghouse on the Thermal/Chemical Degradation of Ceramic Cross-Flow Filter Materials program. In Phase 1 expected filter process conditions were identified for a fixed-bed, fluid-bed, and entrained-bed gasification, direct coal fired turbine, and pressurized fluidized-bed combustion system. Ceramic cross-flow filter materials were also selected, procured, and subjected to chemical and physical characterization. The stability of each of the ceramic cross-flow materials was assessed in terms of potential reactions or phase change as a result of process temperature, and effluent gas compositions containing alkali and fines. In addition chemical and physical characterization was conducted on cross-flow filters that were exposed to the METC fluid-bed gasifier and the New York University pressurized fluidized-bed combustor. Long-term high temperature degradation mechanisms were proposed for each ceramic cross-flow material at process operating conditions. An experimental bench-scale test program is recommended to be conducted in Phase 2, generating data that support the proposed cross-flow filter material thermal/chemical degradation mechanisms. Papers on the individual subtasks have been processed separately for inclusion on the data base.

  9. Bioenergetic Progress and Heat Barriers

    Science.gov (United States)

    Zotin, A. A.; Lamprecht, I.; Zotin, A. I.

    2001-07-01

    Progressing biological evolution is discussed in the framework of nonequilibrium thermodynamics. It is connected with an increase of the mass specific standard metabolism given by coefficient a in the allometric relation (1) between oxygen consumption rate and body mass of an animal. Three “heat barriers” are found in the course of such a bioenergetic evolution. The first heat barrier concerns an animal's overheating during active movement and is overcome by the development of thermoregulation and the appearance of homeothermic animals. A second barrier arises when the coefficient a reaches values connected with lethal body temperatures. The transition across this second heat barrier occurs as result of reasonable activities and the appearance of civilization. The third heat barrier will arise during the further development of human civilization, connected with a highly increased energy production and a fatal warming of the Earth atmosphere. The manner to overcome this barrier will probably depend on the assimilation of space and the establishment of energy consuming industries outside the Earth. The bioenergetic evolution discussed in this paper does not exclude other trends of evolution, e.g. increase of size, and does not mean to be the only aspect of biological evolution.

  10. Explosive opening switch work at Westinghouse

    Science.gov (United States)

    Aivaliotis, E.; Peterhans, M.

    1989-01-01

    An explosive switch that commutated 315 kA into a resistor and a second version designed to switch up to 1 MA into an HPG (homopolar generator)-driven railgun system are presented. These switches are located very near the load and consist of a set of main busbars in a low-inductance configuration shorted by a thinner switch busbar. Linear-shaped charges are used to sever this switch busbar at several locations when a preselected current level is attained, commutating the current into the load. The feasibility of multishot explosive switches for electromagnetic-launch systems is also considered.

  11. Advanced materials for thermal management of electronic packaging

    CERN Document Server

    Tong, Xingcun Colin

    2011-01-01

    The need for advanced thermal management materials in electronic packaging has been widely recognized as thermal challenges become barriers to the electronic industry's ability to provide continued improvements in device and system performance. With increased performance requirements for smaller, more capable, and more efficient electronic power devices, systems ranging from active electronically scanned radar arrays to web servers all require components that can dissipate heat efficiently. This requires that the materials have high capability of dissipating heat and maintaining compatibility

  12. Heat barrier for use in a nuclear reactor facility

    Science.gov (United States)

    Keegan, Charles P.

    1988-01-01

    A thermal barrier for use in a nuclear reactor facility is disclosed herein. Generally, the thermal barrier comprises a flexible, heat-resistant web mounted over the annular space between the reactor vessel and the guard vessel in order to prevent convection currents generated in the nitrogen atmosphere in this space from entering the relatively cooler atmosphere of the reactor cavity which surrounds these vessels. Preferably, the flexible web includes a blanket of heat-insulating material formed from fibers of a refractory material, such as alumina and silica, sandwiched between a heat-resistant, metallic cloth made from stainless steel wire. In use, the web is mounted between the upper edges of the guard vessel and the flange of a sealing ring which surrounds the reactor vessel with a sufficient enough slack to avoid being pulled taut as a result of thermal differential expansion between the two vessels. The flexible web replaces the rigid and relatively complicated structures employed in the prior art for insulating the reactor cavity from the convection currents generated between the reactor vessel and the guard vessel.

  13. Load management for refrigeration systems: Potentials and barriers

    Energy Technology Data Exchange (ETDEWEB)

    Grein, Arne, E-mail: a.grein@tu-berlin.de [University of Technology Berlin, Institute for Energy Technology, Department of Energy Systems, Einsteinufer 25 (TA8), 10587 Berlin (Germany); Pehnt, Martin [Institute for Energy and Environmental Research Heidelberg (ifeu), Wilckensstr. 3, 69120 Heidelberg (Germany)

    2011-09-15

    As a strategy to deal with the increasing intermittent input of renewable energy sources in Germany, the adaptation of power consumption is complementary to power-plant regulation, grid expansion and physical energy storage. One demand sector that promises strong returns for load management efforts is cooling and refrigeration. In these processes, thermal inertia provides a temporal buffer for shifting and adjusting the power consumption of cooling systems. We have conducted an empirical investigation to obtain a detailed and time-resolved bottom-up analysis of load management for refrigeration systems in the city of Mannheim, Germany. We have extrapolated our results to general conditions in Germany. Several barriers inhibit the rapid adoption of load management strategies for cooling systems, including informational barriers, strict compliance with legal cooling requirements, liability issues, lack of technical experience, an inadequate rate of return and organizational barriers. Small commercial applications of refrigeration in the food-retailing and cold storage in hotels and restaurants are particularly promising starting points for intelligent load management. When our results are applied to Germany, suitable sectors for load management have theoretical and achievable potential values of 4.2 and 2.8 GW, respectively, amounting to about 4-6% of the maximum power demand in Germany. - Highlights: > Potential and barriers for implementation of load shifting for refrigeration. > Empirical investigation for time-resolved bottom-up analysis in Mannheim, Germany. > Suitable sectors and further recommendations for introducing load management.> Extrapolation of results from local to national level.

  14. Barrier distributions from elastic scattering

    Energy Technology Data Exchange (ETDEWEB)

    Rowley, N. [Manchester Univ. (United Kingdom). Dept. of Physics]|[Surrey Univ., Guildford (United Kingdom). Dept. of Physics; Timmers, H.; Leigh, J.R.; Masgupta, M.; Hinde, D.J.; Mein, J.C.; Morton, C.R.; Newton, J.O. [Australian National Univ., Canberra, ACT (Australia). Dept. of Nuclear Physics

    1996-01-01

    A new representation of the distribution of potential barriers present in heavy ion reactions is defined in terms of the elastic scattering excitation function. Its validity is demonstrated for the systems {sup 16}0 + {sup 144,} {sup 154}Sm, {sup 186}W, {sup 208}Pb, for which precise measurements have been made. Compared with fusion barrier distributions, which show structures characteristic of collective inelastic couplings, the elastic distributions are less detailed. This appears to be due to couplings to weaker direct reaction channels. 20 refs., 3 figs.

  15. Communication barriers in the family

    Directory of Open Access Journals (Sweden)

    BARBARA KOC-KOZŁOWIEC

    2017-10-01

    Full Text Available The art of communication – listening and speaking – is a major life skill, with a thorough influence on every human life. Remaining silent while the interlocutor speaks is not all that there is to the act of listening to messages. True listening is based on an intention to get involved in understanding of the other person, enjoying his or her presence, learning something from the conversation, giving assistance, or comforting the interlocutor. In the article the author describes obstacles (barriers, which render true listening impossible. These barriers have been identified by a group of young adults.

  16. Prototype Engineered Barrier System Field Tests; Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, A.L.; Beatty, J.; Buscheck, T.A.; Carlson, R.; Daily, W.; LaTorre, V.R.; Lee, K.; Lin, Wunan; Mao, Nai-hsien; Nitao, J.J.; Towse, D.; Ueng, Tzou-Shin; Watwood, D.; Wilder, D.

    1989-07-26

    This paper presents selected preliminary results obtained during the first 54 days of the Prototype Engineered Barrier System Field Tests (PEBSFT) that are being performed in G-Tunnel within the Nevada Test Site. The test described is a precursor to the Engineered Barrier Systems Field Tests (EBSFT). The EBSFT will consist of in situ tests of the geohydrologic and geochemical environment in the near field (within a few meters) of heaters emplaced in welded tuff to simulate the thermal effects of waste packages. The PEBSFTs are being conducted to evaluate the applicability of measurement techniques, numerical models, and procedures for future investigations that will be conducted in the Exploratory Shaft Facilities of the Yucca Mountain Project (YMP). The paper discusses the evolution of hydrothermal behavior during the prototype test, including rock temperatures, changes in rock moisture content, air permeability of fractures, gas pressures, and rock mass gas-phase humidity. 10 refs., 12 figs.

  17. Improvement of barrier properties of rotomolded PE containers with nanoclay

    Energy Technology Data Exchange (ETDEWEB)

    Jamshidi, Shadi; Sundararaj, Uttandaraman, E-mail: u.sundararaj@ucalgary.ca [Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, Alberta, T2N 1N4 (Canada)

    2015-05-22

    Polyethylene (PE) is widely used to make bulk containers in rotational molding process. The challenge in this study is to improve permeation resistance of PE to hydrocarbon solvents and gases. Adding organomodified clay improves the thermal, barrier and mechanical properties of PE. In fact, clay layers create a tortuous path against the permeant, yielding better barrier properties. Due to the non-polar hydrophobic nature of PE and polar hydrophilic structure of clay minerals, the compatibilizer plays a crucial role to enhance the dispersion level of clay in the matrix. In this study High Density Polyethylene (HDPE) and Linear Low Density Polyethylene (LLDPE) layered silicate nanocomposite were melt-compounded with two concentrations of organomodified clay (2 and 4 wt. %). The interaction between nanoclay, compatibilizer and rotomolding grade of PE were examined by using X-ray diffraction, transmission electron microscopy (TEM) and rheology test. Rheology was used to determine the performance of our material at low shear processing condition.

  18. Systems study on engineered barriers: barrier performance analysis

    Energy Technology Data Exchange (ETDEWEB)

    Stula, R.T.; Albert, T.E.; Kirstein, B.E.; Lester, D.H.

    1980-09-01

    A performance assessment model for multiple barrier packages containing unreprocessed spent fuel has been modified and applied to several package designs. The objective of the study was to develop information to be used in programmatic decision making concerning engineered barrier package design and development. The assessment model, BARIER, was developed in previous tasks of the System Study on Engineered Barriers (SSEB). The new version discussed in this report contains a refined and expanded corrosion rate data base which includes pitting, crack growth, and graphitization as well as bulk corrosion. Corrosion rates for oxic and anoxic conditions at each of the two temperature ranges are supplied. Other improvements include a rigorous treatment of radionuclide release after package failure which includes resistance of damaged barriers and backfill, refined temperature calculations that account for convection and radiation, a subroutine to calculate nuclear gamma radiation field at each barrier surface, refined stress calculations with reduced conservatism and various coding improvements to improve running time and core usage. This report also contains discussion of alternative scenarios to the assumed flooded repository as well as the impact of water exclusion backfills. The model was used to assess post repository closure performance for several designs which were all variation of basic designs from the Spent Unreprocessed Fuel (SURF) program. Many designs were found to delay the onset of leaching by at least a few hundreds of years in all geologic media. Long delay times for radionuclide release were found for packages with a few inches of sorption backfill. Release of uranium, plutonium, and americium was assessed.

  19. Neutronic and thermal-hydraulic calculations for the AP-1000 NPP with the MCNP6 and SERPENT codes

    Energy Technology Data Exchange (ETDEWEB)

    Stefani, Giovanni Laranjo; Maiorino, Jose R.; Santos, Thiago A., E-mail: giovanni.laranjo@ufabc.edu.br, E-mail: joserubens.maiorino@ufabc.edu.br, E-mail: thiago.santos@ufabc.edu.br [Universidade Federal do ABC (CECS/UFABC), Santo Andre, SP (Brazil). Centro de Engenharia, Modelagem e Ciencias Sociais; Rossi, Pedro R., E-mail: pedro.russorossi@gmail.com [FERMIUM - Tecnologia Nuclear, Sao Paulo, SP (Brazil)

    2015-07-01

    The AP-1000 is an evolutionary PWR reactor designed as an evolution of the AP-600 project. The reactor is already pre-licensed by NRC, and is considered to have achieved high standards of safety, possible short construction time and good economic competitiveness. The core is a 17x17 typical assembly using Zirlo as cladding, 3 different enrichment regions, and is controlled by boron, control banks, and burnable poison. The expected fuel final burnup is 62 MWD/ton U and a cycle of 18 months. In this paper we present results for neutronic and thermal-hydraulic calculations for the AP-1000. We use the MCNP6 and SERPENT codes to calculate the first cycle of operation. The calculated parameters are K{sub eff} at BOL and EOL and its variation with burnup and neutron flux, and reactivity coefficients. The production of transuranic elements such as Pu-239 and Pu-241, and burning fuel are calculated over time. In the work a complete reactor was burned for 450 days with no control elements, boron or burnable poison were considered, these results were compared with data provided by the Westinghouse. The results are compared with those reported in the literature. A simple thermal hydraulic analysis allows verification of thermal limits such as fuel and cladding temperatures, and MDNB. (author)

  20. Thermal Ignition

    Science.gov (United States)

    Boettcher, Philipp Andreas

    Accidental ignition of flammable gases is a critical safety concern in many industrial applications. Particularly in the aviation industry, the main areas of concern on an aircraft are the fuel tank and adjoining regions, where spilled fuel has a high likelihood of creating a flammable mixture. To this end, a fundamental understanding of the ignition phenomenon is necessary in order to develop more accurate test methods and standards as a means of designing safer air vehicles. The focus of this work is thermal ignition, particularly auto-ignition with emphasis on the effect of heating rate, hot surface ignition and flame propagation, and puffing flames. Combustion of hydrocarbon fuels is traditionally separated into slow reaction, cool flame, and ignition regimes based on pressure and temperature. Standard tests, such as the ASTM E659, are used to determine the lowest temperature required to ignite a specific fuel mixed with air at atmospheric pressure. It is expected that the initial pressure and the rate at which the mixture is heated also influences the limiting temperature and the type of combustion. This study investigates the effect of heating rate, between 4 and 15 K/min, and initial pressure, in the range of 25 to 100 kPa, on ignition of n-hexane air mixtures. Mixtures with equivalence ratio ranging from 0.6 to 1.2 were investigated. The problem is also modeled computationally using an extension of Semenov's classical auto-ignition theory with a detailed chemical mechanism. Experiments and simulations both show that in the same reactor either a slow reaction or an ignition event can take place depending on the heating rate. Analysis of the detailed chemistry demonstrates that a mixture which approaches the ignition region slowly undergoes a significant modification of its composition. This change in composition induces a progressive shift of the explosion limit until the mixture is no longer flammable. A mixture that approaches the ignition region

  1. Polymer layers by initiated chemical vapor deposition for thin film gas barrier encapsulation

    NARCIS (Netherlands)

    Spee, D.A.|info:eu-repo/dai/nl/325843090; Bakker, R.|info:eu-repo/dai/nl/304826677; van der Werf, C.H.M.; van Steenbergen, M.J.|info:eu-repo/dai/nl/304839302; Rath, J.K.|info:eu-repo/dai/nl/304830585; Schropp, R.E.I.|info:eu-repo/dai/nl/072502584

    2011-01-01

    A combination of SiNx and polymer layers, in our case poly(glycidyl methacrylate) (PGMA) is very suitable as a permeation barrier layer on sensitive electronic devices. Our experiments thus far concentrate on increasing the stability and deposition rate of the polymer layers. To reach the thermal

  2. Experimental study of fire barriers preventing vertical fire spread in ETISs

    Directory of Open Access Journals (Sweden)

    Xin Huang

    2013-11-01

    Full Text Available In recent years, the external thermal insulation system (ETIS has been applied increasingly in a large amount of buildings for energy conservation purpose. However, the increase use of combustible insulation materials in the ETIS has raised serious fire safety problems. Fires involving this type of ETIS have caused severe damage and loss. In order to improve its fire safety, fire barriers were suggested to be installed. This paper introduces fire experiments that have been done to study the effects of fire barriers on preventing vertical fire spread along the ETIS. The experiments were performed according to BS 8414-1:2002 “Fire performance of external cladding systems – Part 1: Test method for non-loadbearing external cladding systems applied to the face of the building”. The test facility consists of a 9 m high wall. The fire sources were wood cribs with a fire size of 3 ± 0.5 MW. The insulation materials were expanded polystyrene foam (EPS. The fire barrier was a horizontal strip of rockwool with a width of 300 mm. Thermocouples were used to measure temperatures outside and inside the ETIS. A series of experiments with different fire scenarios were done: no fire barrier, two fire barriers and three fire barriers at different heights. Test results were compared. The results show that the ETIS using EPS without fire barriers almost burned out, while the ETIS with fire barriers performed well in preventing fire spread. The temperatures above the fire barrier were much lower than those below the fire barrier, and most of the insulation materials above the top fire barrier stayed in place.

  3. Overcoming Barriers: Women in Superintendency

    Science.gov (United States)

    Miller, Claire M.

    2009-01-01

    Women currently represent the largest number of teachers in the United States but remain underrepresented in the superintendent position. This suggests that the superintendency has been influenced by patriarchy. If women are to break through the barriers that prevent them from attaining a superintendency, we will need to understand the social…

  4. Functional barriers: Properties and evaluation

    NARCIS (Netherlands)

    Feigenbaum, A.; Dole, P.; Aucejo, S.; Dainelli, D.; Cruz Garcia, C. de la; Hankemeier, T.; N'Gono, Y.; Papaspyrides, C.D.; Paseiro, P.; Pastorelli, S.; Pavlidou, S.; Pennarun, P.Y.; Saillard, P.; Vidal, L.; Vitrac, O.; Voulzatis, Y.

    2005-01-01

    Functional barriers are multilayer structures deemed to prevent migration of some chemicals released by food-contact materials into food. In the area of plastics packaging, different migration behaviours of mono- and multilayer structures are assessed in terms of lag time and of their influence of

  5. Barrier/Cu contact resistivity

    Energy Technology Data Exchange (ETDEWEB)

    Reid, J.S.; Nicolet, M.A. [California Inst. of Tech., Pasadena, CA (United States); Angyal, M.S.; Lilienfeld, D.; Shacham-Diamand, Y. [Cornell Univ., Ithaca, NY (United States); Smith, P.M. [Sandia National Labs., Albuquerque, NM (United States)

    1995-10-17

    The specific contact resistivity of Cu with ({alpha} + {beta})-Ta, TiN, {alpha}-W, and amorphous-Ta{sub 36}Si{sub 14}N{sub 50} barrier films is measured using a novel four-point-probe approach. Geometrically, the test structures consist of colinear sets of W-plugs to act as current and voltage probes that contact the bottom of a planar Cu/barrier/Cu stack. Underlying Al interconnects link the plugs to the current source and voltmeter. The center-to-center distance of the probes ranges from 3 to 200 {micro}m. Using a relation developed by Vu et al., a contact resistivity of roughly 7 {times} 10{sup {minus}9} {Omega} cm{sup 2} is obtained for all tested barrier/Cu combinations. By reflective-mode small-angle X-ray scattering, the similarity in contact resistivity among the barrier films may be related to interfacial impurities absorbed from the deposition process.

  6. Official English: Bridge or Barrier?

    Science.gov (United States)

    Krashen, Stephen

    2000-01-01

    Discusses the official English movement in the United States. Provides suggestions for groups that really want to help immigrants acquire English, by building bridges and not barriers. These include the following: (1) joining private and charitable organizations in helping make English-as-a-Second-Language classes available; (2) support libraries;…

  7. Structure information from fusion barriers

    Indian Academy of Sciences (India)

    effects on the fusion excitation function. However, a simultaneous analysis of the fusion, elastic and quasi-elastic channels would fix the structure and the reaction unambiguously. Keywords. Heavy ion fusion; fusion barrier distributions; nuclear structure; coupled reaction chan- nel calculations. PACS Nos 25.70.Bc; 25.70.

  8. Structure information from fusion barriers

    Indian Academy of Sciences (India)

    The fusion excitation functions for 16O+208Pb, using the coupled reaction channel (CRC) method and correct structure information, have been analysed. The barrier distributions derived from these excitation functions including many of the significant channels are featureless, although these channels have considerable ...

  9. Communication Barriers in Distance Education

    Science.gov (United States)

    Isman, Aytekin; Dabaj, Fahme; Altinay, Fahriye; Altinay, Zehra

    2003-01-01

    Communication is a key concept as being the major tool for people in order to satisfy their needs. It is an activity which refers as process and effective communication requires qualified communication with the elimination of communication barriers. As it is known, distance education is a new trend by following contemporary facilities and tools…

  10. FX barriers with smile dynamics

    NARCIS (Netherlands)

    Baker, Glyn; Beneder, Reimer; Zilber, A.

    2004-01-01

    Our mandate in this work has been to isolate the features of smile consistent models that are most relevant to the pricing of barrier options. We consider the two classical approaches of stochastic and (parametric) local volatility. Although neither has been particularly successful in practice their

  11. Reaction rates when barriers fluctuate

    OpenAIRE

    Reimann, Peter

    1999-01-01

    Reaction rates when barriers fluctuate : a path integral approach / P. Hänggi and P. Reimann. - In: International Conference on Path Integrals from peV to TeV : Proceedings of the ... / eds.: R. Casalbuoni ... - Singapore u.a. : World Scientific, 1999. - S. 407-409

  12. Enabling fast charging – Battery thermal considerations

    Energy Technology Data Exchange (ETDEWEB)

    Keyser, Matthew; Pesaran, Ahmad; Li, Qibo; Santhanagopalan, Shriram; Smith, Kandler; Wood, Eric; Ahmed, Shabbir; Bloom, Ira; Dufek, Eric; Shirk, Matthew; Meintz, Andrew; Kreuzer, Cory; Michelbacher, Christopher; Burnham, Andrew; Stephens, Thomas; Francfort, James; Carlson, Barney; Zhang, Jiucai; Vijayagopal, Ram; Hardy, Keith; Dias, Fernando; Mohanpurkar, Manish; Scoffield, Don; Jansen, Andrew N.; Tanim, Tanvir; Markel, Anthony

    2017-11-01

    Battery thermal barriers are reviewed with regards to extreme fast charging. Present-day thermal management systems for battery electric vehicles are inadequate in limiting the maximum temperature rise of the battery during extreme fast charging. If the battery thermal management system is not designed correctly, the temperature of the cells could reach abuse temperatures and potentially send the cells into thermal runaway. Furthermore, the cell and battery interconnect design needs to be improved to meet the lifetime expectations of the consumer. Each of these aspects is explored and addressed as well as outlining where the heat is generated in a cell, the efficiencies of power and energy cells, and what type of battery thermal management solutions are available in today's market. Thermal management is not a limiting condition with regard to extreme fast charging, but many factors need to be addressed especially for future high specific energy density cells to meet U.S. Department of Energy cost and volume goals.

  13. Coupled neutronic-thermal-hydraulics analysis in a coolant subchannel of a PWR using CFD techniques

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Felipe P.; Su, Jian, E-mail: sujian@nuclear.ufrj.br [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear

    2017-07-01

    The high capacity of Computational Fluid Dynamics code to predict multi-dimensional thermal-hydraulics behaviour and the increased availability of capable computer systems are making that method a good tool to simulate phenomena of thermal-hydraulics nature in nuclear reactors. However, since there are no neutron kinetics models available in commercial CFD codes to the present day, the application of CFD in the nuclear reactor safety analyses is still limited. The present work proposes the implementation of the point kinetics model (PKM) in ANSYS - Fluent to predict the neutronic behaviour in a Westinghouse Sequoyah nuclear reactor, coupling with the phenomena of heat conduction in the rod and thermal-hydraulics in the cooling fluid, via the reactivity feedback. Firstly, a mesh convergence and turbulence model study was performed, using the Reynolds-Average Navier-Stokes method, with square arrayed rod bundle featuring pitch to diameter ratio of 1:32. Secondly, simulations using the k-! SST turbulence model were performed with an axial distribution of the power generation in the fuel to analyse the heat transfer through the gap and cladding, and its in fluence on the thermal-hydraulics behaviour of the cooling fluid. The wall shear stress distribution for the centre-line rods and the dimensionless velocity were evaluated to validate the model, as well as the in fluence of the mass flow rate variation on the friction factor. The coupled model enabled to perform a dynamic analysis of the nuclear reactor during events of insertion of reactivity and shutdown of primary coolant pumps. (author)

  14. POCl3 diffusion with in-situ SiO2 barrier for selective emitter multicrystalline solar grade silicon solar cells

    OpenAIRE

    Urrejola, Elias; Kristian, Peter; Soiland, Anne-Karin; Enebakk, Erik

    2009-01-01

    We present an innovative process for the formation of a selective emitter by using an advanced phosphorous glass as a barrier layer against subsequent diffusion. The advanced barrier glass was achieved by the formation of a standard phosphorous glass treated with additional thermal oxidation immediately after deposition in the same process tube. The resistant layer is used as a barrier for the second diffusion after selective opening of the finger contact areas by screen printing of a SiO2 et...

  15. Altered permeability barrier structure in cholesteatoma matrix

    DEFF Research Database (Denmark)

    Svane-Knudsen, Viggo; Halkier-Sørensen, Lars; Rasmussen, Gurli

    2002-01-01

    lipid structures filling the intercellular spaces mainly control the barrier function. The barrier in cholesteatoma epithelium is several times thicker than in unaffected skin but presents distinctive features of a defective barrier as seen in other scaling skin diseases. The intercellular spaces appear...... frequently occur. The corneocytes are shed in clusters, not as single cells. Further, lipid droplets and intracellular membranous material are occasionally seen. In spite of these clear signs of barrier dysfunction, it is unknown whether the thickness of the barrier compensates for the defect in barrier...

  16. Symbiont Dependent Thermal Bleaching Susceptiblity in Two Reef ...

    African Journals Online (AJOL)

    user1

    Symbiont Dependent Thermal Bleaching Susceptiblity in Two Reef-building Corals, Stylophora pistillata and. Platygyra ryukyuensis ... 2001), on the Great Barrier Reef, Australia (Marshall &. Baird, 2000; Baird .... CHAOS solution (4M guanidine thiocyanate, 0.5% salcosyl, 2.5 mM Tris (pH, 8.0), 0.1 M 2- mercaptoethanol and ...

  17. Crack propagation studies and bond coat properties in thermal ...

    Indian Academy of Sciences (India)

    Ceramic based thermal barrier coatings (TBC) are currently considered as a candidate material for advanced stationary gas turbine components. Crack propagation studies under bending are described that were performed on plasma sprayed ZrO2, bonded by MCrAlY layer to Ni base superalloy. The crack propagation ...

  18. Barriers to improvements in energy efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, A.K.N.

    1991-10-01

    To promote energy-efficiency improvements, actions may be required at one or more levels -- from the lowest level of the consumer (residential, commercial, industrial, etc.) through the highest level of the global agencies. But barriers to the implementation of energy-efficiency improvements exist or can arise at all these levels. Taking up each one of these barriers in turn, the paper discusses specific measures that can contribute to overcoming the barriers. However, a one-barrier-one-measure approach must be avoided. Single barriers may in fact involve several sub-barriers. Also, combinations of measures are much more effective in overcoming barriers. In particular, combinations of measures that simultaneously overcome several barriers are most successful. The paper discusses the typology of barriers, explores their origin and suggests measures that by themselves or in combination with other measures, will overcome these barriers. Since most of the barriers dealt with can be found in the ``barriers`` literature, any originality in the paper lies in its systematic organization, synoptic view and holistic treatment of this issue. This paper is intended to initiate a comprehensive treatment of barriers, their origins and the measures that contribute to overcoming them. Hopefully, such a treatment will facilitate the implementation of energy-efficiency improvements involving a wide diversity of ever-changing energy end uses and consumer preferences.

  19. Barriers to improvements in energy efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, A.K.N.

    1991-10-01

    To promote energy-efficiency improvements, actions may be required at one or more levels -- from the lowest level of the consumer (residential, commercial, industrial, etc.) through the highest level of the global agencies. But barriers to the implementation of energy-efficiency improvements exist or can arise at all these levels. Taking up each one of these barriers in turn, the paper discusses specific measures that can contribute to overcoming the barriers. However, a one-barrier-one-measure approach must be avoided. Single barriers may in fact involve several sub-barriers. Also, combinations of measures are much more effective in overcoming barriers. In particular, combinations of measures that simultaneously overcome several barriers are most successful. The paper discusses the typology of barriers, explores their origin and suggests measures that by themselves or in combination with other measures, will overcome these barriers. Since most of the barriers dealt with can be found in the barriers'' literature, any originality in the paper lies in its systematic organization, synoptic view and holistic treatment of this issue. This paper is intended to initiate a comprehensive treatment of barriers, their origins and the measures that contribute to overcoming them. Hopefully, such a treatment will facilitate the implementation of energy-efficiency improvements involving a wide diversity of ever-changing energy end uses and consumer preferences.

  20. Dynamic thermal environment and thermal comfort.

    Science.gov (United States)

    Zhu, Y; Ouyang, Q; Cao, B; Zhou, X; Yu, J

    2016-02-01

    Research has shown that a stable thermal environment with tight temperature control cannot bring occupants more thermal comfort. Instead, such an environment will incur higher energy costs and produce greater CO2 emissions. Furthermore, this may lead to the degeneration of occupants' inherent ability to combat thermal stress, thereby weakening thermal adaptability. Measured data from many field investigations have shown that the human body has a higher acceptance to the thermal environment in free-running buildings than to that in air-conditioned buildings with similar average parameters. In naturally ventilated environments, occupants have reported superior thermal comfort votes and much greater thermal comfort temperature ranges compared to air-conditioned environments. This phenomenon is an integral part of the adaptive thermal comfort model. In addition, climate chamber experiments have proven that people prefer natural wind to mechanical wind in warm conditions; in other words, dynamic airflow can provide a superior cooling effect. However, these findings also indicate that significant questions related to thermal comfort remain unanswered. For example, what is the cause of these phenomena? How we can build a comfortable and healthy indoor environment for human beings? This article summarizes a series of research achievements in recent decades, tries to address some of these unanswered questions, and attempts to summarize certain problems for future research. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. Patient advocacy: barriers and facilitators

    Directory of Open Access Journals (Sweden)

    Nikravesh Mansoure

    2006-03-01

    Full Text Available Abstract Background During the two recent decades, advocacy has been a topic of much debate in the nursing profession. Although advocacy has embraced a crucial role for nurses, its extent is often limited in practice. While a variety of studies have been generated all over the world, barriers and facilitators in the patient advocacy have not been completely identified. This article presents the findings of a study exploring the barriers and facilitators influencing the role of advocacy among Iranian nurses. Method This study was conducted by grounded theory method. Participants were 24 Iranian registered nurses working in a large university hospital in Tehran, Iran. Semi-structured interviews were used for data collection. All interviews were transcribed verbatim and simultaneously Constant comparative analysis was used according to the Strauss and Corbin method. Results Through data analysis, several main themes emerged to describe the factors that hindered or facilitated patient advocacy. Nurses in this study identified powerlessness, lack of support, law, code of ethics and motivation, limited communication, physicians leading, risk of advocacy, royalty to peers, and insufficient time to interact with patients and families as barriers to advocacy. As for factors that facilitated nurses to act as a patient advocate, it was found that the nature of nurse-patient relationship, recognizing patients' needs, nurses' responsibility, physician as a colleague, and nurses' knowledge and skills could be influential in adopting the advocacy role. Conclusion Participants believed that in this context taking an advocacy role is difficult for nurses due to the barriers mentioned. Therefore, they make decisions and act as a patient's advocate in any situation concerning patient needs and status of barriers and facilitators. In most cases, they can not act at an optimal level; instead they accept only what they can do, which we called 'limited advocacy' in

  2. The Insulation Vacuum Barrier for the Large Hadron Collider (LHC) Magnet Cryostats

    CERN Document Server

    Castoldi, M; Parma, Vittorio; Skoczen, Blazej; Trilhe, P

    2000-01-01

    The sectorisation of the insulation vacuum of the LHC magnet cryostats, housing the superconducting magnets, which operate in a 1.9 K superfluid helium bath, is achieved by means of vacuum barriers. Each vacuum barrier is a leak-tight austenitic stainless steel thin-wall structure, mainly composed of large diameter (between 0.6 m and 0.9 m) bellows and concentric corrugated cylinders. It is mounted in the Short Straight Section (SSS) [1], between the magnet helium enclosure and the vacuum vessel. This paper presents the design of the vacuum barrier, concentrating mostly on its expected thermal performance, to fulfil the tight LHC heat in-leak budgets. Pressure and leak test results, confirming the mechanical design of two prototypes manufactured in industry, and the preparation of one of these vacuum barriers for cryogenic testing in an SSS prototype, are also mentioned.

  3. [Diffusion and diffusion-osmosis models of the charged macromolecule transfer in barriers of biosystems].

    Science.gov (United States)

    Varakin, A I; Mazur, V V; Arkhipova, N V; Serianov, Iu V

    2009-01-01

    Mathematical models of the transfer of charged macromolecules have been constructed on the basis of the classical equations of electromigration diffusion of Helmholtz-Smolukhovskii, Goldman, and Goldman-Hodgkin-Katz. It was shown that ion transfer in placental (mimicking lipid-protein barriers) and muscle barriers occurs by different mechanisms. In placental barriers, the electromigration diffusion occurs along lipid-protein channels formed due to the conformational deformation of phospholipid and protein molecules with the coefficients of diffusion D = (2.6-3.6) x 10(-8) cm2/s. The transfer in muscle barriers is due to the migration across charged interfibrillar channels with the negative diffusion activation energy, which is explained by changes in the structure of muscle fibers and expenditures of thermal energy for the extrusion of Cl- from channel walls with the diffusion coefficient D = (6.0-10.0) x 10(-6) cm2/s.

  4. Sports participation after rehabilitation : Barriers and facilitators

    NARCIS (Netherlands)

    Jaarsma, Eva A; Dekker, Rienk; Geertzen, Jan H.B.; Dijkstra, Pieter

    Objective: To analyse barriers to, and facilitators of, sports participation among people with physical disabilities after rehabilitation and to compare differences between inactive and active participants regarding these experienced barriers and facilitators. Methods: Participants were 1,223 adults

  5. Highway renewable energy : photovoltaic noise barriers

    Science.gov (United States)

    2017-07-01

    Highway photovoltaic noise barriers (PVNBs) represent the combination of noise barrier systems and photovoltaic systems in order to mitigate traffic noise while simultaneously producing renewable energy. First deployed in Switzerland in 1989, PVNBs a...

  6. Security barriers with automated reconnaissance

    Science.gov (United States)

    McLaughlin, James O; Baird, Adam D; Tullis, Barclay J; Nolte, Roger Allen

    2015-04-07

    An intrusion delaying barrier includes primary and secondary physical structures and can be instrumented with multiple sensors incorporated into an electronic monitoring and alarm system. Such an instrumented intrusion delaying barrier may be used as a perimeter intrusion defense and assessment system (PIDAS). Problems with not providing effective delay to breaches by intentional intruders and/or terrorists who would otherwise evade detection are solved by attaching the secondary structures to the primary structure, and attaching at least some of the sensors to the secondary structures. By having multiple sensors of various types physically interconnected serves to enable sensors on different parts of the overall structure to respond to common disturbances and thereby provide effective corroboration that a disturbance is not merely a nuisance or false alarm. Use of a machine learning network such as a neural network exploits such corroboration.

  7. Influence of the geometry of protective barriers on the propagation of shock waves

    Science.gov (United States)

    Sochet, I.; Eveillard, S.; Vinçont, J. Y.; Piserchia, P. F.; Rocourt, X.

    2017-03-01

    The protection of industrial facilities, classified as hazardous, against accidental or intentional explosions represents a major challenge for the prevention of personal injury and property damage, which also involves social and economic issues. We consider here the use of physical barriers against the effects of these explosions, which include the pressure wave, the projection of fragments and the thermal flash. This approach can be recommended for the control of major industrial risks, but no specific instructions are available for its implementation. The influence of a protective barrier against a detonation-type explosion is studied in small-scale experiments. The effects of overpressure are examined over the entire path of the shock wave across the barrier and in the downstream zone to be protected. Two series of barrier structures are studied. The first series (A) of experiments investigates two types of barrier geometry with dimensions based on NATO recommendations. These recommendations stipulate that the barrier should be 2 m higher than the charge height, the thickness at the crest should be more than 0.5 m, while its length should be equal to twice the protected structure length and the bank slope should be equivalent to the angle of repose of the soil. The second series (B) of experiments investigates the influence of geometrical parameters of the barrier (thickness at the crest and inclination angles of the front and rear faces) on its protective effects. This project leads to an advance in our understanding of the physical phenomena involved in the propagation of blast waves resulting from an external explosion, in the area around a protective physical barrier. The study focuses on the dimensioning of protective barriers against overpressure effects arising from detonation and shows the advantage of using a barrier with a vertical front or rear face.

  8. On statistical properties of transport barriers in magnetospheric and laboratory boundary layers

    Science.gov (United States)

    Savin, Sergey; Budaev, Viacheslav; Zeleniy, Lev; Amata, Ermanno; Kozak, Lyudmila; Buechner, Joerg; Romanov, Stanislav; Blecki, Jan; Balikhin, Michael A.; Lezhen, Liudmila

    Transport barriers at outer magnetospheric boundaries have a dualistic feature: being effec-tive in limitation of the momentum transfer and serving as an effective obstacle, they display the super-diffusive statistical properties and provide partial exchange of plasmas. In tokamaks namely the statistical properties of transport barriers look to control the high and low heating modes, while small size of the barriers prevents their detailed studies. We tend to use magne-tospheric multi-spacecraft data to improve understanding of common physics in the transport barriers. We show examples from Interball-1 and Cluster with quiet solar wind. The inherently turbulent crossings in this equilibrium cases demonstrate ion heating namely in the transport barrier. It agrees with the kinetic energy transformation into the thermal one inside the barrier -the turbulent dissipation of the magnetosheath kinetic energy -as simultaneously with the ion temperature rise, the general velocity component drops from its model prediction. In sense of the momentum transfer the transport turbulent barriers effectively isolate the high-alti-tude cusp from fast-flowing magnetosheath. Contrary to that, several examples from different missions and different plasma parameters demonstrate the super-diffusive transport character. The individual coherent structures inside the barriers, which we call Alfvenic 'collapsons', have similar scale chains to that of high kinetic plasma pressure jets, showing mutual interaction features. We think that the interacting jets and barriers, accompanying by classic and/ or micro-reconnection, have rather general importance for the plasma physics, and for understanding of turbulence and mechanisms of magnetic field generation. These coherent, nonlinear interacting structures, most probably, provide intermittency a long-range correlations inside the transport barriers (c.f. blobs and flow spikes in fusion devices). We recall that very high-amplitude turbulence in

  9. Article Including Environmental Barrier Coating System

    Science.gov (United States)

    Lee, Kang N. (Inventor)

    2015-01-01

    An enhanced environmental barrier coating for a silicon containing substrate. The enhanced barrier coating may include a bond coat doped with at least one of an alkali metal oxide and an alkali earth metal oxide. The enhanced barrier coating may include a composite mullite bond coat including BSAS and another distinct second phase oxide applied over said surface.

  10. Market barriers to welfare product innovations

    NARCIS (Netherlands)

    Binnekamp, M.H.A.; Ingenbleek, P.T.M.

    2006-01-01

    New products that are based on higher animal welfare standards encounter several barriers on the road to market acceptance. The authors focus on the Dutch poultry sector and distinguish between retailer and consumer barriers. Retailer barriers include the powerful position of retailers, the price

  11. The Barriers and Needs of Online Learners

    Science.gov (United States)

    Srichanyachon, Napaporn

    2014-01-01

    This study investigated some specific barriers and needs that online students are facing when learning English through WebEx system. It compared students' barriers and needs with their background including gender, computer ownership, and monthly allowance. It also investigated the relationship among computer aptitude, barriers and needs of online…

  12. Design of the Muong Chuoi Barrier

    NARCIS (Netherlands)

    Van Vliegen, K.; Van Oorschot, N.; Meinen, N.; Van Dijk, S.; Reimert, Z.

    2013-01-01

    Ho Chi Minh City has to deal with severe flooding in the rainy season. To prevent the city from this flooding, MARD set up plan 1547. The main idea of the plan is to build a ring dike around HCMC in combination with several movable tidal barriers. One of these barriers is the Muong Chuoi Barrier.

  13. Solar Thermal Energy Technology

    Energy Technology Data Exchange (ETDEWEB)

    Cason, D.L.; Pitsenbarger, J. [eds.

    1996-02-01

    Solar Thermal Energy Technology (PST) announces on a bimonthly basis the current worldwide research and development information that would expand the technology base required for the advancement of solar thermal systems as a significant energy resource.

  14. Ouellette Thermal Test Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Thermal Test Facility is a joint Army/Navy state-of-the-art facility (8,100 ft2) that was designed to:Evaluate and characterize the effect of flame and thermal...

  15. Solar thermal hydrogen production process: Final report, January 1978-December 1982

    Energy Technology Data Exchange (ETDEWEB)

    1982-12-01

    Under sponsorship by the United States Department of Energy, Westinghouse Advanced Energy-Systems Division has investigated the potential for using solar thermal energy to split water into hydrogen and oxygen. A hybrid thermochemical/electrochemical process, known as the Sulfur Cycle, has been the focus of these investigations. Process studies have indicated that, with adequate and ongoing research and development, the Sulfur Cycle can be effectively driven with solar heat. Also, economic analyses have indicated that the cycle has the potential to produce hydrogen in economic competitiveness with conventional methods (e.g. methane/steam reforming) by the turn of the century. A first generation developmental system has been defined along with its critical components, i.e. those components that need substantial engineering development. Designs for those high temperature components that concentrate, vaporize and decompose the process circulating fluid, sulfuric acid, have been prepared. Extensive experimental investigations have been conducted with regard to the selection of construction materials for these components. From these experiments, which included materials endurance tests for corrosion resistance for periods up to 6000 hours, promising materials and catalysts have been identified.

  16. Simplified thermal-hydraulic analysis of single phase natural circulation circuit with two heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Pinheiro, Larissa Cunha; Su, Jian, E-mail: larissa@lasme.coppe.ufrj.br, E-mail: sujian@lasme.coppe.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenhraria Nuclear; Cotta, Renato Machado, E-mail: cotta@mecanica.coppe.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (POLI/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Dept. de Engenharia Mecanica

    2015-07-01

    Single phase natural circulation circuits composed of two convective heat exchangers and connecting tubes are important for the passive heat removal from spent fuel pools (SFP). To keep the structural integrity of the stored spent fuel assemblies, continuously cooling has to be provided in order to avoid increase at the pool temperature and subsequent uncovering of the fuel and enhanced reaction between water and metal releasing hydrogen. Decay heat can achieve considerably high amounts of energy e.g. in the AP1000, considering the emergency fuel assemblies, the maximum heat decay will reach 13 MW in the 15th day (Westinghouse Electric Company, 2010). A highly efficient alternative to do so is by means of natural circulation, which is cost-effective compared to active cooling systems and is inherently safer since presents less associated devices and no external work is required. Many researchers have investigated safety and stability aspects of natural circulation loops (NCL). However, there is a lack of literature concerning the improvement of NCL through a standard unified methodology, especially for natural circulation circuits with two heat exchangers. In the present study, a simplified thermal-hydraulic analysis of single phase natural circulation circuit with two heat exchanges is presented. Relevant dimensionless key groups were proposed to for the design and safety analysis of a scaled NCL for the cooling of spent fuel storage pool with convective cooling and heating. (author)

  17. Ocean Thermal Energy Conversion power system development. Phase I: preliminary design. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1978-12-04

    Westinghouse has completed the Preliminary Desigh Phase for the Power System Development of the Ocean Thermal Energy Conversion (OTEC) Demonstration Plant project. This study included the development of a preliminary design for a Modular Application scaled power system (10MWe) and Heat Exchanger Test Articles, both based on the concept developed in the Conceptual Design Phase. The results of this study were used to improve the baseline design of the 50MWe module for the Commercial Size Power System, which was recommended for the demonstration plant by the conceptual design study. The 50MWe module was selected since it has the lowest cost, and since its size convincingly demonstrates that future economically viable commercial plants, having reliable operation with credible anticipated costs, are possible. Additional optimization studies on the size of the power system plus hull continue to identify 50MWe as the preferred minimum cost configuration. This study was limited to a closed cycle ammonia power system module, using a seawater temperature difference of 40/sup 0/F, and a surface platform/ship reference hull. This volume presents the preliminary design configuration and system optimization. (WHK)

  18. Phase 1: conceptual design. Ocean thermal energy conversion power system development. Volume 2 of 3. Technical details. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1978-01-30

    Westinghouse has completed the conceptual design of the Power System for the Ocean Thermal Energy Conversion (OTEC) Demonstration Plant project. This study included the development of a conceptual design for the following three items: first, a full-size power system module for the 100 MWe Demonstration Plant; second, a scaled proof of concept power system; and third, a heat exchanger test article. The study was limited to a closed cycle ammonia power system module, using a water temperature difference of 40/sup 0/F., and a surface platform/ship reference hull. Two power module of 50 MWe each are recommended for the demonstration plant. The 50 MWe module was selected since it has the lowest cost, and since it is of a size which convincingly demonstrates that future economically viable commercial plants, having reliable operation with credible anticipated costs, are possible. A modular, tube bundle approach to heat exchanger design makes large heat exchangers practical and economical. Other power module elements are considered to be within state-of-practice. Technological assessments of all subsystems indicate requirements for verification only, rather than continued research. A complete test program, which will verify the mechanical reliability as well as thermal performance, is recommended.

  19. Electric Motor Thermal Management

    Energy Technology Data Exchange (ETDEWEB)

    Bennion, Kevin S [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-01

    Thermal management enables more efficient and cost-effective motors. This Annual Merit Review presentation describes the technical accomplishments and progress in electric motor thermal management R&D over the last year. This project supports a broad industry demand for data, analysis methods, and experimental techniques to improve and better understand motor thermal management.

  20. Thermal Performance Benchmarking (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, G.

    2014-11-01

    This project will benchmark the thermal characteristics of automotive power electronics and electric motor thermal management systems. Recent vehicle systems will be benchmarked to establish baseline metrics, evaluate advantages and disadvantages of different thermal management systems, and identify areas of improvement to advance the state-of-the-art.

  1. Effect of orbital and ionic dynamics coupling in barrier crossing rates for Car-Parrinello molecular dynamics

    Science.gov (United States)

    Mohanam, L. N.; Ong, S. W.; Tok, E. S.; Kang, H. C.

    2015-02-01

    Even though the Car-Parrinello molecular dynamics (CPMD) method provides excellent sampling for thermal equilibrium, coupling between ionic motion and the fictitious orbital dynamics leads to an underestimation of ionic vibration frequencies In this letter we examine how this coupling affects calculated rates of energy-barrier crossing. Simulating double-well potentials in 'toy' models based on H3O2- and H5O2+ complexes, we demonstrate that barrier crossing rates can be dramatically affected depending upon how orbitals evolve at the top of the reaction barrier. Thus, it is important that calculated dynamical quantities such as chemical reaction rates be assessed for this coupling effect.

  2. Luminescence dating of Holocene sedimentary deposits on Rømø, a barrier island in the Wadden Sea, Denmark

    DEFF Research Database (Denmark)

    Madsen, Anni Tindahl; Murray, Andrew S.; Andersen, Thorbjørn Joest

    2010-01-01

    This study presents an Optically Stimulated Luminescence (OSL) based chronology for the evolution of the barrier island Rømø and related back-barrier lagoon deposits in the Danish Wadden Sea. The chronology is constructed using 78 quartz OSL ages obtained using a Single Aliquot Regenerative dose...... (SAR) protocol; samples were retrieved from seven sediment cores, each up to 25 m long, taken from locations on the island and within the back-barrier lagoon. The reliability of the OSL results is assessed using preheat plateaus, thermal transfer tests, and dose recovery measurements, and by comparison...

  3. Double barrier system for an in situ conversion process

    Energy Technology Data Exchange (ETDEWEB)

    McKinzie, Billy John [Houston, TX; Vinegar, Harold J [Bellaire, TX; Cowan, Kenneth Michael [Sugar land, TX; Deeg, Wolfgang Friedrich Johann [Houston, TX; Wong, Sau-Wai [Rijswijk, NL

    2009-05-05

    A barrier system for a subsurface treatment area is described. The barrier system includes a first barrier formed around at least a portion of the subsurface treatment area. The first barrier is configured to inhibit fluid from exiting or entering the subsurface treatment area. A second barrier is formed around at least a portion of the first barrier. A separation space exists between the first barrier and the second barrier.

  4. Smart Building: Decision Making Architecture for Thermal Energy Management

    Directory of Open Access Journals (Sweden)

    Oscar Hernández Uribe

    2015-10-01

    Full Text Available Smart applications of the Internet of Things are improving the performance of buildings, reducing energy demand. Local and smart networks, soft computing methodologies, machine intelligence algorithms and pervasive sensors are some of the basics of energy optimization strategies developed for the benefit of environmental sustainability and user comfort. This work presents a distributed sensor-processor-communication decision-making architecture to improve the acquisition, storage and transfer of thermal energy in buildings. The developed system is implemented in a near Zero-Energy Building (nZEB prototype equipped with a built-in thermal solar collector, where optical properties are analysed; a low enthalpy geothermal accumulation system, segmented in different temperature zones; and an envelope that includes a dynamic thermal barrier. An intelligent control of this dynamic thermal barrier is applied to reduce the thermal energy demand (heating and cooling caused by daily and seasonal weather variations. Simulations and experimental results are presented to highlight the nZEB thermal energy reduction.

  5. Smart Building: Decision Making Architecture for Thermal Energy Management.

    Science.gov (United States)

    Uribe, Oscar Hernández; Martin, Juan Pablo San; Garcia-Alegre, María C; Santos, Matilde; Guinea, Domingo

    2015-10-30

    Smart applications of the Internet of Things are improving the performance of buildings, reducing energy demand. Local and smart networks, soft computing methodologies, machine intelligence algorithms and pervasive sensors are some of the basics of energy optimization strategies developed for the benefit of environmental sustainability and user comfort. This work presents a distributed sensor-processor-communication decision-making architecture to improve the acquisition, storage and transfer of thermal energy in buildings. The developed system is implemented in a near Zero-Energy Building (nZEB) prototype equipped with a built-in thermal solar collector, where optical properties are analysed; a low enthalpy geothermal accumulation system, segmented in different temperature zones; and an envelope that includes a dynamic thermal barrier. An intelligent control of this dynamic thermal barrier is applied to reduce the thermal energy demand (heating and cooling) caused by daily and seasonal weather variations. Simulations and experimental results are presented to highlight the nZEB thermal energy reduction.

  6. Smart Building: Decision Making Architecture for Thermal Energy Management

    Science.gov (United States)

    Hernández Uribe, Oscar; San Martin, Juan Pablo; Garcia-Alegre, María C.; Santos, Matilde; Guinea, Domingo

    2015-01-01

    Smart applications of the Internet of Things are improving the performance of buildings, reducing energy demand. Local and smart networks, soft computing methodologies, machine intelligence algorithms and pervasive sensors are some of the basics of energy optimization strategies developed for the benefit of environmental sustainability and user comfort. This work presents a distributed sensor-processor-communication decision-making architecture to improve the acquisition, storage and transfer of thermal energy in buildings. The developed system is implemented in a near Zero-Energy Building (nZEB) prototype equipped with a built-in thermal solar collector, where optical properties are analysed; a low enthalpy geothermal accumulation system, segmented in different temperature zones; and an envelope that includes a dynamic thermal barrier. An intelligent control of this dynamic thermal barrier is applied to reduce the thermal energy demand (heating and cooling) caused by daily and seasonal weather variations. Simulations and experimental results are presented to highlight the nZEB thermal energy reduction. PMID:26528978

  7. Clays in natural and engineered barriers for radioactive waste confinement

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    The meeting covers all topics concerning natural argillaceous geological barriers and the clay material based engineered barrier systems, investigated by means of: laboratory experiments on clay samples (new analytical developments), in situ experiments in underground research laboratories, mock-up demonstrations, natural analogues, as well as numerical modelling and global integration approaches (including up-scaling processes and treatment of uncertainties). The works presented deal with: examples of broad research programs (national or international) on the role of natural and artificial clay barriers for radionuclide confinement; clay-based repository concepts: repository designs, including technological and safety issues related to the use of clay for nuclear waste confinement; geology and clay characterisation: mineralogy, sedimentology, paleo-environment, diagenesis, dating techniques, discontinuities in rock clay, fracturing, self sealing processes, role of organic matter and microbiological processes; geochemistry: pore water geochemistry, clay thermodynamics, chemical retention, geochemical modelling, advanced isotopic geochemistry; mass transfer: water status and hydraulic properties in low permeability media, pore space geometry, water, solute and gas transfer processes, colloid mediated transport, large scale movements, long-term diffusion; alteration processes: oxidation effects, hydration-dehydration processes, response to thermal stress, iron-clay interactions, alkaline perturbation; geomechanics: thermo-hydro-mechanical behaviour of clay, rheological models, EDZ characterisation and evolution, coupled behaviour and models (HM, THM, THMC). A particular interest is given to potential contributions coming from fields of activities other than radioactive waste management, which take advantage of the confinement properties of the clay barrier (oil and gas industries, gas geological storage, CO{sub 2} geological sequestration, chemical waste isolation

  8. Engineered Barrier System: Physical and Chemical Environment Model

    Energy Technology Data Exchange (ETDEWEB)

    D. M. Jolley; R. Jarek; P. Mariner

    2004-02-09

    The conceptual and predictive models documented in this Engineered Barrier System: Physical and Chemical Environment Model report describe the evolution of the physical and chemical conditions within the waste emplacement drifts of the repository. The modeling approaches and model output data will be used in the total system performance assessment (TSPA-LA) to assess the performance of the engineered barrier system and the waste form. These models evaluate the range of potential water compositions within the emplacement drifts, resulting from the interaction of introduced materials and minerals in dust with water seeping into the drifts and with aqueous solutions forming by deliquescence of dust (as influenced by atmospheric conditions), and from thermal-hydrological-chemical (THC) processes in the drift. These models also consider the uncertainty and variability in water chemistry inside the drift and the compositions of introduced materials within the drift. This report develops and documents a set of process- and abstraction-level models that constitute the engineered barrier system: physical and chemical environment model. Where possible, these models use information directly from other process model reports as input, which promotes integration among process models used for total system performance assessment. Specific tasks and activities of modeling the physical and chemical environment are included in the technical work plan ''Technical Work Plan for: In-Drift Geochemistry Modeling'' (BSC 2004 [DIRS 166519]). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system analysis model reports.

  9. Thermal Management and Thermal Protection Systems

    Science.gov (United States)

    Hasnain, Aqib

    2016-01-01

    During my internship in the Thermal Design Branch (ES3), I contributed to two main projects: i) novel passive thermal management system for future human exploration, ii) AVCOAT undercut thermal analysis. i) As NASA prepares to further expand human and robotic presence in space, it is well known that spacecraft architectures will be challenged with unprecedented thermal environments. Future exploration activities will have the need of thermal management systems that can provide higher reliability, mass and power reduction and increased performance. In an effort to start addressing the current technical gaps the NASA Johnson Space Center Passive Thermal Discipline has engaged in technology development activities. One of these activities was done through an in-house Passive Thermal Management System (PTMS) design for a lunar lander. The proposed PTMS, functional in both microgravity and gravity environments, consists of three main components: a heat spreader, a novel hybrid wick Variable Conductance Heat Pipe (VCHP), and a radiator. The aim of this PTMS is to keep electronics on a vehicle within their temperature limits (0 and 50 C for the current design) during all mission phases including multiple lunar day/night cycles. The VCHP was tested to verify its thermal performance. I created a thermal math model using Thermal Desktop (TD) and analyzed it to predict the PTMS performance. After testing, the test data provided a means to correlate the thermal math model. This correlation took into account conduction and convection heat transfer, representing the actual benchtop test. Since this PTMS is proposed for space missions, a vacuum test will be taking place to provide confidence that the system is functional in space environments. Therefore, the model was modified to include a vacuum chamber with a liquid nitrogen shroud while taking into account conduction and radiation heat transfer. Infrared Lamps were modelled and introduced into the model to simulate the sun

  10. Quantum Thermal Transistor.

    Science.gov (United States)

    Joulain, Karl; Drevillon, Jérémie; Ezzahri, Younès; Ordonez-Miranda, Jose

    2016-05-20

    We demonstrate that a thermal transistor can be made up with a quantum system of three interacting subsystems, coupled to a thermal reservoir each. This thermal transistor is analogous to an electronic bipolar one with the ability to control the thermal currents at the collector and at the emitter with the imposed thermal current at the base. This is achieved by determining the heat fluxes by means of the strong-coupling formalism. For the case of three interacting spins, in which one of them is coupled to the other two, that are not directly coupled, it is shown that high amplification can be obtained in a wide range of energy parameters and temperatures. The proposed quantum transistor could, in principle, be used to develop devices such as a thermal modulator and a thermal amplifier in nanosystems.

  11. Effects and Mechanism of Atmospheric-Pressure Dielectric Barrier Discharge Cold Plasma on Lactate Dehydrogenase (LDH) Enzyme

    OpenAIRE

    Hao Zhang; Zimu Xu; Jie Shen; Xu Li; Lili Ding; Jie Ma; Yan Lan; Weidong Xia; Cheng Cheng; Qiang Sun; Zelong Zhang; Chu, Paul K

    2015-01-01

    Proteins are carriers of biological functions and the effects of atmospheric-pressure non-thermal plasmas on proteins are important to applications such as sterilization and plasma-induced apoptosis of cancer cells. Herein, we report our detailed investigation of the effects of helium-oxygen non-thermal dielectric barrier discharge (DBD) plasmas on the inactivation of lactate dehydrogenase (LDH) enzyme solutions. Circular dichroism (CD) and dynamic light scattering (DLS) indicate that the los...

  12. Barriers to Medical Error Reporting.

    Science.gov (United States)

    Poorolajal, Jalal; Rezaie, Shirin; Aghighi, Negar

    2015-01-01

    This study was conducted to explore the prevalence of medical error underreporting and associated barriers. This cross-sectional study was performed from September to December 2012. Five hospitals, affiliated with Hamadan University of Medical Sciences, in Hamedan, Iran were investigated. A self-administered questionnaire was used for data collection. Participants consisted of physicians, nurses, midwives, residents, interns, and staffs of radiology and laboratory departments. Overall, 50.26% of subjects had committed but not reported medical errors. The main reasons mentioned for underreporting were lack of effective medical error reporting system (60.0%), lack of proper reporting form (51.8%), lack of peer supporting a person who has committed an error (56.0%), and lack of personal attention to the importance of medical errors (62.9%). The rate of committing medical errors was higher in men (71.4%), age of 50-40 years (67.6%), less-experienced personnel (58.7%), educational level of MSc (87.5%), and staff of radiology department (88.9%). This study outlined the main barriers to reporting medical errors and associated factors that may be helpful for healthcare organizations in improving medical error reporting as an essential component for patient safety enhancement.

  13. Barriers to medical error reporting

    Directory of Open Access Journals (Sweden)

    Jalal Poorolajal

    2015-01-01

    Full Text Available Background: This study was conducted to explore the prevalence of medical error underreporting and associated barriers. Methods: This cross-sectional study was performed from September to December 2012. Five hospitals, affiliated with Hamadan University of Medical Sciences, in Hamedan,Iran were investigated. A self-administered questionnaire was used for data collection. Participants consisted of physicians, nurses, midwives, residents, interns, and staffs of radiology and laboratory departments. Results: Overall, 50.26% of subjects had committed but not reported medical errors. The main reasons mentioned for underreporting were lack of effective medical error reporting system (60.0%, lack of proper reporting form (51.8%, lack of peer supporting a person who has committed an error (56.0%, and lack of personal attention to the importance of medical errors (62.9%. The rate of committing medical errors was higher in men (71.4%, age of 50-40 years (67.6%, less-experienced personnel (58.7%, educational level of MSc (87.5%, and staff of radiology department (88.9%. Conclusions: This study outlined the main barriers to reporting medical errors and associated factors that may be helpful for healthcare organizations in improving medical error reporting as an essential component for patient safety enhancement.

  14. Overcoming Barriers in Unhealthy Settings

    Directory of Open Access Journals (Sweden)

    Michael K. Lemke

    2016-03-01

    Full Text Available We investigated the phenomenon of sustained health-supportive behaviors among long-haul commercial truck drivers, who belong to an occupational segment with extreme health disparities. With a focus on setting-level factors, this study sought to discover ways in which individuals exhibit resiliency while immersed in endemically obesogenic environments, as well as understand setting-level barriers to engaging in health-supportive behaviors. Using a transcendental phenomenological research design, 12 long-haul truck drivers who met screening criteria were selected using purposeful maximum sampling. Seven broad themes were identified: access to health resources, barriers to health behaviors, recommended alternative settings, constituents of health behavior, motivation for health behaviors, attitude toward health behaviors, and trucking culture. We suggest applying ecological theories of health behavior and settings approaches to improve driver health. We also propose the Integrative and Dynamic Healthy Commercial Driving (IDHCD paradigm, grounded in complexity science, as a new theoretical framework for improving driver health outcomes.

  15. Mucus as a Barrier to Drug Delivery

    DEFF Research Database (Denmark)

    Bøgh, Marie; Nielsen, Hanne Mørck

    2015-01-01

    Viscoelastic mucus lines all mucosal surfaces of the body and forms a potential barrier to mucosal drug delivery. Mucus is mainly composed of water and mucins; high-molecular weight glycoproteins forming an entangled network. Consequently, mucus forms a steric barrier and due to its negative charge...... and hydrophobic domains, the overall hydrophilic mucus also presents an interactive barrier limiting the free diffusion of components within and through the mucus. Furthermore, mucus is a dynamic barrier due to its continuous secretion and shedding from the mucosal surfaces. Mucus is thus a highly complex gel...... barrier to drug delivery. Current knowledge of mucus characteristics and barrier properties, as achieved by state-of-the-art methodologies, is the topic of this MiniReview emphasizing the gastrointestinal mucus and an overall focus on oral drug delivery. Cell culture-based in vitro models are well...

  16. Barrier experiment: Shock initiation under complex loading

    Energy Technology Data Exchange (ETDEWEB)

    Menikoff, Ralph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-01-12

    The barrier experiments are a variant of the gap test; a detonation wave in a donor HE impacts a barrier and drives a shock wave into an acceptor HE. The question we ask is: What is the trade-off between the barrier material and threshold barrier thickness to prevent the acceptor from detonating. This can be viewed from the perspective of shock initiation of the acceptor subject to a complex pressure drive condition. Here we consider key factors which affect whether or not the acceptor undergoes a shock-to-detonation transition. These include the following: shock impedance matches for the donor detonation wave into the barrier and then the barrier shock into the acceptor, the pressure gradient behind the donor detonation wave, and the curvature of detonation front in the donor. Numerical simulations are used to illustrate how these factors affect the reaction in the acceptor.

  17. Storm impacts on small barrier islands

    DEFF Research Database (Denmark)

    Kroon, Aart; Fruergaard, Mikkel

    water levels. These storms induce collision, overwash or inundation of the barrier crest and generate wash-over fans and barrier breaching. In this presentation, we focus on the present-day morphologic evolution of these barrier islands, couple these to extreme events, and we will predict the potential......The shorelines of the Baltic Sea and the inner coastal waters in Denmark consist of many barrier islands. These sandy barrier islands were mainly formed in the Holocene and are still very dynamic. The present day changes in the morphology are dominantly governed by storm waves and associated high...... changes in this evolution due to changes in the climate and associated sea levels. We analyzed the morphologic evolution of a series of barrier islands over the last decades using maps, aerial photographs and satellite images. This decadal morphologic evolution was coupled to the frequency and intensity...

  18. Factors for Consideration in an Open-Flame Test for Assessing Fire Blocking Performance of Barrier Fabrics

    Directory of Open Access Journals (Sweden)

    Shonali Nazaré

    2016-09-01

    Full Text Available The main objective of the work reported here is to assess factors that could affect the outcome of a proposed open flame test for barrier fabrics (BF-open flame test. The BF-open flame test characterizes barrier effectiveness by monitoring the ignition of a flexible polyurethane foam (FPUF layer placed in contact with the upper side of the barrier fabric, exposed to a burner flame from below. Particular attention is given to the factors that influence the ignitibility of the FPUF, including thermal resistance, permeability, and structural integrity of the barrier fabrics (BFs. A number of barrier fabrics, displaying a wide range of the properties, are tested with the BF-open flame test. Visual observations of the FPUF burning behavior and BF char patterns, in addition to heat flux measurements on the unexposed side of the barrier fabrics, are used to assess the protective performance of the BF specimen under the open flame test conditions. The temperature and heat transfer measurements on the unexposed side of the BF and subsequent ranking of BFs for their thermal protective performance suggest that the BF-open flame test does not differentiate barrier fabrics based on their heat transfer properties. A similar conclusion is reached with regard to BF permeability characterized at room temperature. However, the outcome of this BF-open flame test is found to be heavily influenced by the structural integrity of thermally degraded BF. The BF-open flame test, in its current form, only ignited FPUF when structural failure of the barrier was observed.

  19. Identification of Key Barriers in Workforce Development

    Energy Technology Data Exchange (ETDEWEB)

    None

    2008-03-31

    This report documents the identification of key barriers in the development of an adequate national security workforce as part of the National Security Preparedness Project, being performed under a Department of Energy/National Nuclear Security Administration grant. Many barriers exist that prevent the development of an adequate number of propertly trained national security personnel. Some barriers can be eliminated in a short-term manner, whereas others will involve a long-term strategy that takes into account public policy.

  20. Barrier Engineered Quantum Dot Infrared Photodetectors

    Science.gov (United States)

    2015-06-01

    AFRL-RV-PS- AFRL-RV-PS- TR-2015-0111 TR-2015-0111 BARRIER ENGINEERED QUANTUM DOT INFRARED PHOTODETECTORS Sanjay Krishna Center for High Technology...2011 – 22 May 2012 4. TITLE AND SUBTITLE Barrier Engineered Quantum Dot Infrared Photodetectors 5a. CONTRACT NUMBER FA9453-12-1-0336 5b. GRANT...is Unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT To investigate barrier engineered designs to reduce the dark current in quantum dot infrared

  1. Perceived Barriers to Walking for Physical Activity

    OpenAIRE

    Dunton, Genevieve F.; Schneider, Margaret

    2006-01-01

    Introduction Although the health benefits of walking for physical activity have received increasing research attention, barriers specific to walking are not well understood. In this study, questions to measure barriers to walking for physical activity were developed and tested among college students. The factor structure, test–retest and internal consistency reliability, and discriminant and criterion validity of the perceived barriers were evaluated. Methods A total of 305 undergraduate stud...

  2. Barriers for realisation of energy savings in buildings; Barrierer for realisering af energibesparelser i bygninger

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, O.M.

    2004-07-01

    Many years' efforts within the energy labelling area have shown large saving potentials in heating and use of electricity in buildings. At the same time it has been proved that these saving potentials, even when economically advantageous, only are cashed to a limited extent. The reason to this is ascribed to barriers that meet the individual building owner who wants to start saving energy. Most barriers are known and a lot of these have been sought overcome for some time. The questions are how many barriers still exist, have new barriers arisen and the character of these barriers. On this background the objective of this survey has been to concretize and study the barriers, which are blocking reasonable energy savings. Focus has especially been on barriers for realisation of heating savings, but through a general evaluation of energy savings of barriers other forms of energy saving methods have been taken into consideration. Special interest has been directed towards houses, typically one family houses, which are affected by the Energy Labelling Scheme. The concept barriers include all kinds of barriers, also barriers that not are acknowledged as barriers by the individual house owner, or that on closer inspection turn out to be something else than actual barriers. This note suggests an alternative inertia model, in order to create an idea of the inertness characteristic of the many house owners who understand the message but fail to act on it. (BA)

  3. Barriers to Health Care for Transgender Individuals

    Science.gov (United States)

    Safer, Joshua D.; Coleman, Eli; Feldman, Jamie; Garofalo, Robert; Hembree, Wylie; Radix, Asa; Sevelius, Jae

    2016-01-01

    Purpose of Review Transgender persons suffer significant health disparities and may require medical intervention as part of their care. The purpose of this manuscript is to briefly review the literature characterizing barriers to health care for transgender individuals and to propose research priorities to understand mechanisms of those barriers and interventions to overcome them. Recent Findings Current research emphasizes sexual minorities’ self report of barriers, rather than using direct methods. The biggest barrier to health care reported by transgender individuals is lack of access due to lack of providers who are sufficiently knowledgeable on the topic. Other barriers include: financial barriers, discrimination, lack of cultural competence by providers, health systems barriers and socioeconomic barriers. Summary National research priorities should include rigorous determination of the capacity of the United States health care system to provide adequate care for transgender individuals. Studies should determine knowledge and biases of the medical work force across the spectrum of medical training with regard to transgender medical care; adequacy of sufficient providers for the care required, larger social structural barriers and status of a framework to pay for appropriate care. As well, studies should propose and validate potential solutions to address identified gaps. PMID:26910276

  4. Exercise barriers in Korean colorectal cancer patients.

    Science.gov (United States)

    Kang, Dong-Woo; Chung, Jae Youn; Lee, Mi Kyung; Lee, Junga; Park, Ji-Hye; Kim, Dong-Il; Jones, Lee W; Ahn, Joong Bae; Kim, Nam Kyu; Jeon, Justin Y

    2014-01-01

    To identify barriers to exercise in Korean colorectal cancer patients and survivors, and to analyze differences in exercise barriers by age, gender, treatment status, and physical activity level. A total of 427 colorectal cancer patients and survivors from different stages and medical status completed a self-administered questionnaire that surveyed their barriers to exercise and exercise participation. The greatest perceived exercise barriers for the sampled population as a whole were fatigue, low level of physical fitness, and poor health. Those under 60-years old reported lack of time (p=0.008), whereas those over 60 reported low level of physical fitness (p=0.014) as greater exercise barriers than their counterparts. Women reported fatigue as a greater barrier than men (pACSM guidelines, cancer-related exercise barriers were additionally reported (p<0.001), compared to those who were. Our study suggests that fatigue, low level of physical fitness, and poor health are most reported exercise barriers for Korean colorectal cancer survivors and there are differences in exercise barriers by age, sex, treatment status, and physical activity level. Therefore, support for cancer patients should be provided considering these variables to increase exercise participation.

  5. Sports participation after rehabilitation: Barriers and facilitators

    National Research Council Canada - National Science Library

    Jaarsma, Eva A; Dekker, Rienk; Geertzen, Jan H.B; Dijkstra, Pieter

    2016-01-01

    Objective: To analyse barriers to, and facilitators of, sports participation among people with physical disabilities after rehabilitation and to compare differences between inactive and active participants...

  6. Radon barrier: Method of testing airtightness

    DEFF Research Database (Denmark)

    Rasmussen, Torben Valdbjørn; Buch-Hansen, Thomas Cornelius

    2017-01-01

    The test method NBI 167/02 Radon membrane: Test of airtightness can be used for determining the airtightness of a radon barrier as a system solution. The test determines the air infiltration through the radon barrier for a number of levels of air pressure differences. The airflow through versus...... of the barrier with the low air pressure, through a well-defined opening, as a modification of the test method in general. Results, obtained using the improved test method, are shown for a number of radon barriers tested....

  7. Barriers Approach to Innovation in Academic Libraries

    Directory of Open Access Journals (Sweden)

    Fu-Hsuan Chuang

    2016-11-01

    Full Text Available Innovation in academic libraries is not a brand new issue. Academic libraries can benefit from successful innovation, since innovation is a key contributor to gaining and sustaining competitive advantage for survival. Building on two case studies, 28 participants from leadership teams to practitioners are involved, the qualitative findings identified the specific two types of barriers that academic libraries face by applying a barriers approach to innovation, that’s, environmental and organizational barriers. Especially, seven dimensions of two types of barriers to innovation are found.

  8. Polyspermy barriers: a plant perspective.

    Science.gov (United States)

    Tekleyohans, Dawit G; Mao, Yanbo; Kägi, Christina; Stierhof, York-Dieter; Groß-Hardt, Rita

    2017-02-01

    A common denominator of sexual reproduction in many eukaryotic species is the exposure of an egg to excess sperm to maximize the chances of reproductive success. To avoid potential harmful or deleterious consequences of supernumerary sperm fusion to a single female gamete (polyspermy), many eukaryotes, including plants, have evolved barriers preventing polyspermy. Typically, these checkpoints are implemented at different stages in the reproduction process. The virtual absence of unambiguous reports of naturally occurring egg cell polyspermy in flowering plants is likely reflecting the success of this multiphasic strategy and highlights the difficulty to trace this presumably rare event. We here focus on potential polyspermy avoidance mechanisms in plants and discuss them in light of analogous processes in animals. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  9. Thermal Imaging in Aviation

    Directory of Open Access Journals (Sweden)

    Marek Štumper

    2015-10-01

    Full Text Available This article focuses on the use of thermal imaging in aviation. In the never ending pursuit of lower costs, the Thermal Imaging offers shorter inspection times thanks to its application in aircraft inspections and can reduce the number of costly goarounds using the Enhanced Vision System, which also increases safety in one of the most dangerous parts of flight. Thermal Imaging also offers solutions for Airport Perimeter Security and it can be used for construction of ground surveillance system.

  10. Thermal waveguide OPO.

    Science.gov (United States)

    Lin, S T; Lin, Y Y; Wang, T D; Huang, Y C

    2010-01-18

    We report a mid-infrared, CW singly resonant optical parametric oscillator (OPO) with a thermally induced waveguide in its gain crystal. We measured a numerical aperture of 0.0062 for the waveguide at 80-W intracavity power at 3.2 microm. This thermal-guiding effect benefits to the stable operation of an OPO and improves the parametric conversion efficiency by more than a factor of two when compared with that without thermal guiding.

  11. Thermal Hyperbolic Metamaterials

    OpenAIRE

    Guo, Yu; Jacob, Zubin

    2013-01-01

    We explore the near-field radiative thermal energy transfer properties of hyperbolic metamaterials. The presence of unique electromagnetic states in a broad bandwidth leads to super-planckian thermal energy transfer between metamaterials separated by a nano-gap. We consider practical phonon-polaritonic metamaterials for thermal engineering in the mid-infrared range and show that the effect exists in spite of the losses, absorption and finite unit cell size. For thermophotovoltaic energy conve...

  12. Building Thermal Models

    Science.gov (United States)

    Peabody, Hume L.

    2017-01-01

    This presentation is meant to be an overview of the model building process It is based on typical techniques (Monte Carlo Ray Tracing for radiation exchange, Lumped Parameter, Finite Difference for thermal solution) used by the aerospace industry This is not intended to be a "How to Use ThermalDesktop" course. It is intended to be a "How to Build Thermal Models" course and the techniques will be demonstrated using the capabilities of ThermalDesktop (TD). Other codes may or may not have similar capabilities. The General Model Building Process can be broken into four top level steps: 1. Build Model; 2. Check Model; 3. Execute Model; 4. Verify Results.

  13. Thermal microactuator dimension analysis

    Science.gov (United States)

    Azman, N. D.; Ong, N. R.; Aziz, M. H. A.; Alcain, J. B.; Haimi, W. M. W. N.; Sauli, Z.

    2017-09-01

    The focus of this study was to analyse the stress and thermal flow of thermal microactuator with different type of materials and parameter using COMSOL Multiphysics software. Simulations were conducted on the existing thermal actuator and integrated it to be more efficient, low cost and low power consumption. In this simulation, the U-shaped actuator was designed and five different materials of the microactuator were studied. The result showed that Si Polycrystalline was the most suitable material used to produce thermal actuator for commercialization.

  14. Thermal Performance Benchmarking

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Xuhui; Moreno, Gilbert; Bennion, Kevin

    2016-06-07

    The goal for this project is to thoroughly characterize the thermal performance of state-of-the-art (SOA) in-production automotive power electronics and electric motor thermal management systems. Information obtained from these studies will be used to: evaluate advantages and disadvantages of different thermal management strategies; establish baseline metrics for the thermal management systems; identify methods of improvement to advance the SOA; increase the publicly available information related to automotive traction-drive thermal management systems; help guide future electric drive technologies (EDT) research and development (R&D) efforts. The thermal performance results combined with component efficiency and heat generation information obtained by Oak Ridge National Laboratory (ORNL) may then be used to determine the operating temperatures for the EDT components under drive-cycle conditions. In FY16, the 2012 Nissan LEAF power electronics and 2014 Honda Accord Hybrid power electronics thermal management system were characterized. Comparison of the two power electronics thermal management systems was also conducted to provide insight into the various cooling strategies to understand the current SOA in thermal management for automotive power electronics and electric motors.

  15. Theory of thermal stresses

    CERN Document Server

    Boley, Bruno A

    1997-01-01

    Highly regarded text presents detailed discussion of fundamental aspects of theory, background, problems with detailed solutions. Basics of thermoelasticity, heat transfer theory, thermal stress analysis, more. 1985 edition.

  16. Effect of Water on the Formation of Barriers to Melt Transport in the Martian Lithosphere

    Science.gov (United States)

    Schools, J.; Montesi, L.

    2016-12-01

    The mantle is often considered as an aggregate of two phases: a solid, porous matrix and a liquid melt (McKenzie, 1984; Bercovici et al., 2001). Melt travels rapidly upwards through the matrix due to its buoyancy. When this melt enters the colder lithosphere it begins to crystallize. If the crystallization happens a high rate, then the newly formed crystals can clog the pore space, reducing its permeability to essentially zero (Korenaga and Kelemen, 1997). This area of zero permeability is the permeability barrier. We use the MELTS family of thermodynamic calculators (e.g. Ghiorso and Sack, 1995) to determine melt compositions and the crystallization sequence of ascending melt throughout Martian history to simulate the formation of permeability barriers. At low strain rates (10-17-10-15 s-1) permeability barriers form deep in the lithosphere, possibly contributing to the evolution of localized volcanic edifices on the Martian surface once fracturing or thermal erosion enables melt to traverse the lithosphere. Higher strain rates (10-13 s-1) yield shallower permeability barriers, which may be related to extensive lava flows. The behavior of permeability barrier formation from anhydrous mantle source to 0.5 wt.% H2O mantle source is investigated. Introducing small amounts of water ( 60 ppm H2O) has a similar effect to increasing the strain rate, forming shallower barriers. Large amounts of water (0.5 wt.% H2O) yield very shallow, weak barriers or no barriers at all. Melt reaches the Martian surface most easily in areas of increased tectonics or areas with an increased mantle water content.

  17. High performance metal-supported solid oxide fuel cells with Gd-doped ceria barrier layers

    DEFF Research Database (Denmark)

    Klemensø, Trine; Nielsen, Jimmi; Blennow Tullmar, Peter

    2011-01-01

    Metal-supported solid oxide fuel cells are believed to have commercial advantages compared to conventional anode (Ni–YSZ) supported cells, with the metal-supported cells having lower material costs, increased tolerance to mechanical and thermal stresses, and lower operational temperatures......, and an electrochemical performance beyond the state-of-the-art anode-supported SOFC is demonstrated possible, by introducing a CGO barrier layer in combination with Sr-doped lanthanum cobalt oxide (LSC) cathode. Area specific resistances (ASR) down to 0.27 Ω cm2, corresponding to a maximum power density of 1.14 W cm−2...... at 650 °C and 0.6 V, were obtained on cells with barrier layers fabricated by magnetron sputtering. The performance is dependent on the density of the barrier layer, indicating Sr2+ diffusion is occurring at the intermediate SOFC temperatures. The optimized design further demonstrate improved durability...

  18. Variable pressure thermal insulating jacket

    Science.gov (United States)

    Nelson, Paul A.; Malecha, Richard F.; Chilenskas, Albert A.

    1994-01-01

    A device for controlled insulation of a thermal device. The device includes a thermal jacket with a closed volume able to be evacuated to form an insulating jacket around the thermal source. A getter material is in communcation with the closed volume of the thermal jacket. The getter material can absorb and desorb a control gas to control gas pressure in the volume of the thermal jacket to control thermal conductivity in the thermal jacket.

  19. Revisiting the Integrated Pressurized Thermal Shock Studies of an Aging Pressurized Water Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bryson, J.W.; Dickson, T.L.; Malik, S.N.M.; Simonen, F.A.

    1999-08-01

    The Integrated Pressurized Thermal Shock (IPTS) studies were a series of studies performed in the early-mid 1980s as part of an NRC-organized comprehensive research project to confirm the technical bases for the pressurized thermal shock (PTS) rule, and to aid in the development of guidance for licensee plant-specific analyses. The research project consisted of PTS pilot analyses for three PWRs: Oconee Unit 1, designed by Babcock and Wilcox; Calvert Cliffs Unit 1, designed by Combustion Engineering; and H.B. Robinson Unit 2, designed by Westinghouse. The primary objectives of the IPTS studies were (1) to provide for each of the three plants an estimate of the probability of a crack propagating through the wall of a reactor pressure vessel (RPV) due to PTS; (2) to determine the dominant overcooling sequences, plant features, and operator actions and the uncertainty in the plant risk due to PTS; and (3) to evaluate the effectiveness of potential corrective actions. The NRC is currently evaluating the possibility of revising current PTS regulatory guidance. Technical bases must be developed to support any revisions. In the years since the results of IPTS studies were published, the fracture mechanics model, the embrittlement database, embrittlement correlation, inputs for flaw distributions, and the probabilistic fracture mechanics (PFM) computer code have been refined. An ongoing effort is underway to determine the impact of these fracture-technology refinements on the conditional probabilities of vessel failure calculated in the IPTS Studies. This paper discusses the results of these analyses performed for one of these plants.

  20. Novel PET Nanocomposites of Interest in Food Packaging Applications and Comparative Barrier Performance With Biopolyester Nanocomposites

    OpenAIRE

    Sanchez-Garcia, M.D.; Gimenez, E.; Lagaron, J.M.

    2007-01-01

    Abstract Poly(ethylene terephthalate) (PET) is one of the polymers most widely used in the packaging industry. However, it is highly desirable to enhance its barrier properties for applications, such as carbonated drinks and other rigid and flexible packaging applications. The nanocomposites route offers unique possibilities to enhance the properties of this material, provided that adequate thermally resistant and legislation complying nanoadditives are used. This study presents no...