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Sample records for innovative high thermal

  1. An Innovative High Thermal Conductivity Fuel Design

    SciTech Connect

    PI: James S. Tulenko; Co-PI: Ronald H. Baney,

    2007-10-14

    Uranium dioxide (UO2) is the most common fuel material in commercial nuclear power reactors. UO2 has the advantages of a high melting point, good high-temperature stability, good chemical compatibility with cladding and coolant, and resistance to radiation. The main disadvantage of UO2 is its low thermal conductivity. During a reactor’s operation, because the thermal conductivity of UO2 is very low, for example, about 2.8 W/m-K at 1000 oC [1], there is a large temperature gradient in the UO2 fuel pellet, causing a very high centerline temperature, and introducing thermal stresses, which lead to extensive fuel pellet cracking. These cracks will add to the release of fission product gases after high burnup. The high fuel operating temperature also increases the rate of fission gas release and the fuel pellet swelling caused by fission gases bubbles. The amount of fission gas release and fuel swelling limits the life time of UO2 fuel in reactor. In addition, the high centerline temperature and large temperature gradient in the fuel pellet, leading to a large amount of stored heat, increase the Zircaloy cladding temperature in a lost of coolant accident (LOCA). The rate of Zircaloy-water reaction becomes significant at the temperature above 1200 oC [2]. The ZrO2 layer generated on the surface of the Zircaloy cladding will affect the heat conduction, and will cause a Zircaloy cladding rupture. The objective of this research is to increase the thermal conductivity of UO2, while not affecting the neutronic property of UO2 significantly. The concept to accomplish this goal is to incorporate another material with high thermal conductivity into the UO2 pellet. Silicon carbide (SiC) is a good candidate, because the thermal conductivity of single crystal SiC is 60 times higher than that of UO2 at room temperature and 30 times higher at 800 oC [3]. Silicon carbide also has the properties of low thermal neutron absorption cross section, high melting point, good chemical

  2. An Innovative High Thermal Conductivity Fuel Design

    SciTech Connect

    Jamil A. Khan

    2009-11-21

    Thermal conductivity of the fuel in today's Light Water Reactors, Uranium dioxide, can be improved by incorporating a uniformly distributed heat conducting network of a higher conductivity material, Silicon Carbide. The higher thermal conductivity of SiC along with its other prominent reactor-grade properties makes it a potential material to address some of the related issues when used in UO2 [97% TD]. This ongoing research, in collaboration with the University of Florida, aims to investigate the feasibility and develop a formal methodology of producing the resultant composite oxide fuel. Calculations of effective thermal conductivity of the new fuel as a function of %SiC for certain percentages and as a function of temperature are presented as a preliminary approach. The effective thermal conductivities are obtained at different temperatures from 600K to 1600K. The corresponding polynomial equations for the temperature-dependent thermal conductivities are given based on the simulation results. Heat transfer mechanism in this fuel is explained using a finite volume approach and validated against existing empirical models. FLUENT 6.1.22 was used for thermal conductivity calculations and to estimate reduction in centerline temperatures achievable within such a fuel rod. Later, computer codes COMBINE-PC and VENTURE-PC were deployed to estimate the fuel enrichment required, to maintain the same burnup levels, corresponding to a volume percent addition of SiC.

  3. INNOVATIVE THERMAL TREATMENT PROCESSES

    EPA Science Inventory

    The paper contains discussions of several innovative thermal processes for treating or destroying hazardous wastes. Processes discussed can be included in the categories wet oxidation, molten glass, fluidized bed incineration, pyrolysis, molten salt, electric reactors, and plasma...

  4. INNOVATIVE THERMAL DESTRUCTION TECHNOLOGIES

    EPA Science Inventory

    Ten innovative technologies for thermally destroying hazardous wastes were selected and described in this paper. hese technologies were either supported by EPA's RCRA or SARA programs or developed by industry since 1980. wo of the important criteria used in selecting these techno...

  5. Innovative hybrid heat sink materials with high thermal conductivities and tailored CTE

    NASA Astrophysics Data System (ADS)

    Kitzmantel, M.; Neubauer, E.

    2015-02-01

    This paper talks about high performance heat sinks and heat spreaders made by hybrid structures based on metaldiamond composites. Thermal conductivities can be tuned between 450 and 650 W/mK while maintaining customizable thermal expansion of 6-10 ppm/K (@30°C). Using different hybrid structures in combination with the metal-diamond core significant changes in thermal properties can be identified. Applications targeted are LED, disc laser and laser diode heatsinks with these high performance inserts without the need of CTE matched submounts.

  6. COMPARISON OF INNOVATIVE TECHNOLOGY FOR THERMAL DESTRUCTION OF HAZARDOUS WASTE

    EPA Science Inventory

    This paper briefly summaries and compares six technologies which are considered to be innovative to the thermal destruction of hazardous wastes. The six technologies are: Fluidized Bed, Molten Salt, High Temperature Fluid Wall, Plasma Arc, Wet Air Oxidation and Supercritical Wate...

  7. Flameless thermal oxidation. Innovative technology summary report

    SciTech Connect

    1995-09-01

    The Flameless Thermal Oxidizer (FTO) is a commercial technology offered by Thermatrix, Inc. The FTO has been demonstrated to be an effective destructive technology for process and waste stream off-gas treatment of volatile organic compounds (VOCs), and in the treatment of VOC and chlorinated volatile organic compounds (CVOCs) off-gases generated during site remediation using either baseline or innovative in situ environmental technologies. The FTO process efficiently converts VOCs and CVOCs to carbon dioxide, water, and hydrogen chloride. When FTO is coupled with a baseline technology, such as soil vapor extraction (SVE), an efficient in situ soil remediation system is produced. The innovation is in using a simple, reliable, scalable, and robust technology for the destruction of VOC and CVOC off-gases based on a design that generates a uniform thermal reaction zone that prevents flame propagation and efficiently oxidizes off-gases without forming products of incomplete combustion (PICs).

  8. Flameless Thermal Oxidation. Innovative Technology Summary Report

    SciTech Connect

    1995-09-01

    The Flameless Thermal Oxidizer (FTO) is a commercial technology offered by Thermatrix, Inc. The FTO has been demonstrated to be an effective destructive technology for process and waste stream off-gas treatment of volatile organic compounds (VOCs), and in the treatment of VOC and chlorinated volatile organic compounds (CVOCs) off-gases generated during site remediation using either baseline or innovative in situ environmental technologies. The FTO process efficiently converts VOCs and CVOCs to carbon dioxide, water, and hydrogen chloride. When FTO is coupled with a baseline technology, such as soil vapor extraction (SVE), an efficient in situ soil remediation system is produced. The innovation is in using a simple, reliable, scalable, and robust technology for the destruction of VOC and CVOC off-gases based on a design that generates a uniform thermal reaction zone that prevents flame propagation and efficiently oxidizes off-gases without forming products of incomplete combustion (Plcs ).

  9. Development of Innovative Accident Tolerant High Thermal Conductivity UO2-Diamond Composite Fuel Pellets

    SciTech Connect

    Tulenko, James; Subhash, Ghatu

    2016-01-01

    The University of Florida (UF) evaluated a composite fuel consisting of UO2 powder mixed with diamond micro particles as a candidate as an accident-tolerant fuel (ATF). The research group had previous extensive experience researching with diamond micro particles as an addition to reactor coolant for improved plant thermal performance. The purpose of this research work was to utilize diamond micro particles to develop UO2-Diamond composite fuel pellets with significantly enhanced thermal properties, beyond that already being measured in the previous UF research projects of UO2 – SiC and UO2 – Carbon Nanotube fuel pins. UF is proving with the current research results that the addition of diamond micro particles to UO2 may greatly enhanced the thermal conductivity of the UO2 pellets producing an accident-tolerant fuel. The Beginning of life benefits have been proven and fuel samples are being irradiated in the ATR reactor to confirm that the thermal conductivity improvements are still present under irradiation.

  10. Innovative approach to retrieve land surface emissivity and land surface temperature in areas of highly dynamic emissivity changes by using thermal infrared data

    NASA Astrophysics Data System (ADS)

    Heinemann, S.

    2015-12-01

    The land surface temperature (LST) is an extremely significant parameter in order to understand the processes of energetic interactions between Earth's surface and atmosphere. This knowledge is significant for various environmental research questions, particularly with regard to the recent climate change. This study shows an innovative approach to retrieve land surface emissivity (LSE) and LST by using thermal infrared (TIR) data from satellite sensors, such as SEVIRI and AATSR. So far there are no methods to derive LSE/LST particularly in areas of highly dynamic emissivity changes. Therefore especially for regions with large surface temperature amplitude in the diurnal cycle such as bare and uneven soil surfaces but also for regions with seasonal changes in vegetation cover including various surface areas such as grassland, mixed forests or agricultural land different methods were investigated to identify the most appropriate one. The LSE is retrieved by using the day/night Temperature-Independent Spectral Indices (TISI) method, and the Generalised Split-Window (GSW) method is used to retrieve the LST. Nevertheless different GSW algorithms show that equal LSEs lead to large LST differences. Additionally LSE is also measured using a NDVI-based threshold method (NDVITHM) to distinguish between soil, dense vegetation cover and pixel composed of soil and vegetation. The data used for this analysis were derived from MODIS TIR. The analysis is implemented with IDL and an intercomparison is performed to determine the most effective methods. To compensate temperature differences between derived and ground truth data appropriate correction terms by comparing derived LSE/LST data with ground-based measurements are developed. One way to calibrate LST retrievals is by comparing the canopy leaf temperature of conifers derived from TIR data with the surrounding air temperature (e.g. from synoptic stations). Prospectively, the derived LSE/LST data become validated with near

  11. Innovative approach to retrieve land surface emissivity and land surface temperature in areas of highly dynamic emissivity changes by using thermal infrared data

    NASA Astrophysics Data System (ADS)

    Heinemann, Sascha; Muro, Javier; Burkart, Andreas; Schultz, Johannes; Thonfeld, Frank; Menz, Gunter

    2016-04-01

    The land surface temperature (LST) is an extremely significant parameter in order to understand the processes of energetic interactions between the Earth's surface and the atmosphere. This knowledge is significant for various environmental research questions, particularly with regard to climate change. The current challenge is to reduce the higher deviations during daytime especially for bare areas with a maximum of 5.7 Kelvin. These temperature differences are time and vegetation cover dependent. This study shows an innovative approach to retrieve land surface emissivity (LSE) and LST by using thermal infrared (TIR) data from satellite sensors, such as SEVIRI and AATSR. So far there are no methods to derive LSE/LST particularly in areas of highly dynamic emissivity changes. Therefore especially for regions with large surface temperature amplitude in the diurnal cycle such as bare and uneven soil surfaces but also for regions with seasonal changes in vegetation cover including various surface areas such as grassland, mixed forests or agricultural land different methods were investigated to identify the most appropriate one. The LSE is retrieved by using the day/night Temperature-Independent Spectral Indices (TISI) method, while the Generalised Split-Window (GSW) method is used to retrieve the LST. Nevertheless different GSW algorithms show that equal LSEs lead to large LST differences. For bare surfaces during daytime the difference is about 6 Kelvin. Additionally LSE is also measured using a NDVI-based threshold method (NDVITHM) to distinguish between soil, dense vegetation cover and pixel composed of soil and vegetation. The data used for this analysis were derived from MODIS TIR. The analysis is implemented with IDL and an intercomparison is performed to determine the most effective methods. To compensate temperature differences between derived and ground truth data appropriate correction terms, by comparing derived LSE/LST data with ground-based measurements

  12. Highly directional thermal emitter

    DOEpatents

    Ribaudo, Troy; Shaner, Eric A; Davids, Paul; Peters, David W

    2015-03-24

    A highly directional thermal emitter device comprises a two-dimensional periodic array of heavily doped semiconductor structures on a surface of a substrate. The array provides a highly directional thermal emission at a peak wavelength between 3 and 15 microns when the array is heated. For example, highly doped silicon (HDSi) with a plasma frequency in the mid-wave infrared was used to fabricate nearly perfect absorbing two-dimensional gratings structures that function as highly directional thermal radiators. The absorption and emission characteristics of the HDSi devices possessed a high degree of angular dependence for infrared absorption in the 10-12 micron range, while maintaining high reflectivity of solar radiation (.about.64%) at large incidence angles.

  13. Development of an Innovative High-Thermal Conductivity UO2 Ceramic Composites Fuel Pellets with Carbon Nano-Tubes Using Spark Plasma Sintering

    SciTech Connect

    Subhash, Ghatu; Wu, Kuang-Hsi; Tulenko, James

    2014-03-10

    Uranium dioxide (UO2) is the most common fuel material in commercial nuclear power reactors. Despite its numerous advantages such as high melting point, good high-temperature stability, good chemical compatibility with cladding and coolant, and resistance to radiation, it suffers from low thermal conductivity that can result in large temperature gradients within the UO2 fuel pellet, causing it to crack and release fission gases. Thermal swelling of the pellets also limits the lifetime of UO2 fuel in the reactor. To mitigate these problems, we propose to develop novel UO2 fuel with uniformly distributed carbon nanotubes (CNTs) that can provide high-conductivity thermal pathways and can eliminate fuel cracking and fission gas release due to high temperatures. CNTs have been investigated extensively for the past decade to explore their unique physical properties and many potential applications. CNTs have high thermal conductivity (6600 W/mK for an individual single- walled CNT and >3000 W/mK for an individual multi-walled CNT) and high temperature stability up to 2800°C in vacuum and about 750°C in air. These properties make them attractive candidates in preparing nano-composites with new functional properties. The objective of the proposed research is to develop high thermal conductivity of UO2–CNT composites without affecting the neutronic property of UO2 significantly. The concept of this goal is to utilize a rapid sintering method (5–15 min) called spark plasma sintering (SPS) in which a mixture of CNTs and UO2 powder are used to make composites with different volume fractions of CNTs. Incorporation of these nanoscale materials plays a fundamentally critical role in controlling the performance and stability of UO2 fuel. We will use a novel in situ growth process to grow CNTs on UO2 particles for rapid sintering and develop UO2-CNT composites. This method is expected to provide a uniform distribution of CNTs at various volume fractions so that a high

  14. Highly Thermal Conductive Nanocomposites

    NASA Technical Reports Server (NTRS)

    Sun, Ya-Ping (Inventor); Connell, John W. (Inventor); Veca, Lucia Monica (Inventor)

    2015-01-01

    Disclosed are methods for forming carbon-based fillers as may be utilized in forming highly thermal conductive nanocomposite materials. Formation methods include treatment of an expanded graphite with an alcohol/water mixture followed by further exfoliation of the graphite to form extremely thin carbon nanosheets that are on the order of between about 2 and about 10 nanometers in thickness. Disclosed carbon nanosheets can be functionalized and/or can be incorporated in nanocomposites with extremely high thermal conductivities. Disclosed methods and materials can prove highly valuable in many technological applications including, for instance, in formation of heat management materials for protective clothing and as may be useful in space exploration or in others that require efficient yet light-weight and flexible thermal management solutions.

  15. High-Thermal-Conductivity Fabrics

    NASA Technical Reports Server (NTRS)

    Chibante, L. P. Felipe

    2012-01-01

    Heat management with common textiles such as nylon and spandex is hindered by the poor thermal conductivity from the skin surface to cooling surfaces. This innovation showed marked improvement in thermal conductivity of the individual fibers and tubing, as well as components assembled from them. The problem is centered on improving the heat removal of the liquid-cooled ventilation garments (LCVGs) used by astronauts. The current design uses an extensive network of water-cooling tubes that introduces bulkiness and discomfort, and increases fatigue. Range of motion and ease of movement are affected as well. The current technology is the same as developed during the Apollo program of the 1960s. Tubing material is hand-threaded through a spandex/nylon mesh layer, in a series of loops throughout the torso and limbs such that there is close, form-fitting contact with the user. Usually, there is a nylon liner layer to improve comfort. Circulating water is chilled by an external heat exchanger (sublimator). The purpose of this innovation is to produce new LCVG components with improved thermal conductivity. This was addressed using nanocomposite engineering incorporating high-thermalconductivity nanoscale fillers in the fabric and tubing components. Specifically, carbon nanotubes were added using normal processing methods such as thermoplastic melt mixing (compounding twin screw extruder) and downstream processing (fiber spinning, tubing extrusion). Fibers were produced as yarns and woven into fabric cloths. The application of isotropic nanofillers can be modeled using a modified Nielsen Model for conductive fillers in a matrix based on Einstein s viscosity model. This is a drop-in technology with no additional equipment needed. The loading is limited by the ability to maintain adequate dispersion. Undispersed materials will plug filtering screens in processing equipment. Generally, the viscosity increases were acceptable, and allowed the filled polymers to still be

  16. Innovative site remediation technology: Thermal desorption. Volume 6

    SciTech Connect

    Anderson, W.C.

    1993-11-01

    The monograph on thermal desorption is one of a series of eight on innovative site and waste remediation technologies that are the culmination of a multiorganization effort involving more than 100 experts over a two-year period. The thermal desorption processes addressed in this monograph use heat, either direct or indirect, ex situ, as the principal means to physically separate and transfer contaminants from soils, sediments, sludges, filter cakes, or other media. Thermal desorption is part of a treatment train; some pre- and postprocessing is necessary.

  17. Thermal Denitration. Innovative Technology Summary Report

    SciTech Connect

    2001-09-01

    The major object of this work was to provide data for identifying and demonstrating a technically viable and cost-effective approach to condition LAW for immobilization. Pacific Northwest National Laboratory evaluated an approach that consisted of distillation followed by low-temperature denitration with a reductant addition. This process option minimizes volatilization of radionuclides and hazardous constituents, and converts most of the nitrate in the water to at least 50% nitrogen gas instead of NOx during LAW calcination, while still producing a groutable product. INEEL investigated high-temperature calcination for the LAW, a process already selected by INEEL for calcining high-level waste. Why is it necessary to remove the nitrate (denitrification)? The low-activity waste derived from the separation work performed on the sodium-bearing waste will be very acidic as will the high-activity waste from the redissolution of calcine. In addition, these waste streams will contain very high levels of nitrates; these nitrates are detrimental to grout waste forms. Thus, the nitrate must be removed from these waste streams before they are encapsulated in grout.

  18. Thermal conductance measurement of windows: An innovative radiative method

    SciTech Connect

    Arpino, F.; Buonanno, G.; Giovinco, G.

    2008-09-15

    Heat transfer through window surfaces is one of the most important contributions to energy losses in buildings. Therefore, great efforts are made to design new window frames and glass assemblies with low thermal conductance. At the same time, it is also necessary to develop accurate measurement techniques in thermal characterisation of the above-mentioned building components. In this paper the authors show an innovative measurement method mainly based on radiative heat transfer (instead of the traditional convective one) which allows window thermal conductance measurements with corresponding uncertainty budget evaluation. The authors used the 3D finite volume software FLUENT {sup registered} to design the experimental apparatus. The numerical results have been employed for the system optimisation and metrological characterisation. (author)

  19. Innovative Multi-Environment, Multimode Thermal Control System

    NASA Technical Reports Server (NTRS)

    Singh, Bhim S.; Hasan, Mohammad H.

    2007-01-01

    Innovative multi-environment multimode thermal management architecture has been described that is capable of meeting widely varying thermal control requirements of various exploration mission scenarios currently under consideration. The proposed system is capable of operating in a single-phase or two-phase mode rejecting heat to the colder environment, operating in a two-phase mode with heat pump for rejecting heat to a warm environment, as well as using evaporative phasechange cooling for the mission phases where the radiator is incapable of rejecting the required heat. A single fluid loop can be used internal and external to the spacecraft for the acquisition, transport and rejection of heat by the selection of a working fluid that meets NASA safety requirements. Such a system may not be optimal for each individual mode of operation but its ability to function in multiple modes may permit global optimization of the thermal control system. The architecture also allows flexibility in partitioning of components between the various Constellation modules to take advantage of operational requirements in various modes consistent with the mission needs. Preliminary design calculations using R-134 as working fluid show the concept to be feasible to meet the heat rejection requirements that are representative of the Crew Exploration Vehicle and Lunar Access Module for nominal cases. More detailed analyses to establish performance under various modes and environmental conditions are underway.

  20. High velocity pulsed plasma thermal spray

    NASA Astrophysics Data System (ADS)

    Witherspoon, F. D.; Massey, D. W.; Kincaid, R. W.; Whichard, G. C.; Mozhi, T. A.

    2002-03-01

    The quality and durability of coatings produced by many thermal spray techniques could be improved by increasing the velocity with which coating particles impact the substrate. Additionally, better control of the chemical and thermal environment seen by the particles during flight is crucial to the quality of the coating. A high velocity thermal spray device is under development through a Ballistic Missile Defense Organization Small Business Innovation Research (SBIR) project, which provides significantly higher impact velocity for accelerated particles than is currently available with existing thermal spray devices. This device utilizes a pulsed plasma as the accelerative medium for powders introduced into the barrel. Recent experiments using a particle imaging diagnostic system showed that the device can accelerate stainless steel and WC-Co powders to velocities ranging from 1500 to 2200 m/s. These high velocities are accomplished without the use of combustible gases and without the need of a vacuum chamber, while maintaining an inert atmosphere for the particles during acceleration. The high velocities corresponded well to modeling predictions, and these same models suggest that velocities as high as 3000 m/s or higher are possible.

  1. High temperature solar thermal technology

    NASA Technical Reports Server (NTRS)

    Leibowitz, L. P.; Hanseth, E. J.; Peelgren, M. L.

    1980-01-01

    Some advanced technology concepts under development for high-temperature solar thermal energy systems to achieve significant energy cost reductions and performance gains and thus promote the application of solar thermal power technology are presented. Consideration is given to the objectives, current efforts and recent test and analysis results in the development of high-temperature (950-1650 C) ceramic receivers, thermal storage module checker stoves, and the use of reversible chemical reactions to transport collected solar energy. It is pointed out that the analysis and testing of such components will accelerate the commercial deployment of solar energy.

  2. Thermal analysis of an innovative heat pump operated desalination plant

    SciTech Connect

    Site, V.D.

    1995-12-31

    Sea and brackish water desalination can contribute to solve the problem of fresh water shortage in many and regions of the world. Nowadays most of the installed desalination plants employ distillation processes, like Multistage Flash (MSF), Multi effect Distillation (MED) and Vapor Compression (VC). VC process is called Mechanical Vapor Compression (MVC) when it employs a mechanical compressor, while it is called Thermal Compression when it employs a steam-ejector compressor. In this paper a new distillation plant for the treatment of sea water for drinking water purposes is presented. The most innovative feature of this system is the use of a heat pump as part of the desalting unit. The use of the heat pump in the proposed system enables desalting water evaporation and steam condensation at the same temperature, unlike conventional VC desalting systems where a steam compression stage is necessary. A thermal analysis of the heat pump-operated desalination (HPD) plant and a comparison between the HPD and a conventional MVC plant is presented, in order to determine the main advantages and disadvantages of the new system.

  3. Innovators.

    ERIC Educational Resources Information Center

    NEA Today, 2001

    2001-01-01

    Describes various innovations that have been developed to enhance education. These innovations include: helping educators help at-risk students succeed; promoting high school journalism; ensuring quality online learning experiences; developing a student performing group that uses theater to address social issues; and having students design their…

  4. Innovative coal gasification system with high temperature air

    SciTech Connect

    Yoshikawa, K.; Katsushima, H.; Kasahara, M.; Hasegawa, T.; Tanaka, R.; Ootsuka, T.

    1997-12-31

    This paper proposes innovative coal gasification power generation systems where coal is gasified with high temperature air of about 1300K produced by gasified coal fuel gas. The main features of these systems are high thermal efficiency, low NO{sub x} emission, compact desulfurization and dust removal equipment and high efficiency molten slag removal with a very compact gasifier. Recent experimental results on the pebble bed coal gasifier appropriate for high temperature air coal gasification are reported, where 97.7% of coal ash is successfully caught in the pebble bed and extracted without clogging. A new concept of high temperature air preheating system is proposed which is characterized by its high reliability and low cost.

  5. MAOS: An Innovative Way to Teach High School.

    ERIC Educational Resources Information Center

    Harray, Nancy; And Others

    1997-01-01

    Describes an innovative high school program that uses oceanography, mathematics, and science as common threads in the instructional program. The program utilizes an innovative class structure, community involvement, and hands on activities. (DDR)

  6. High thermal conductivity of diamond

    NASA Technical Reports Server (NTRS)

    Stephan, Patrick M.

    1993-01-01

    The objectives of this educational exercise were to demonstrate the high rate of heat flow from a synthetic diamond coupon and to compare it to a commonly used thermal conductor, such as copper. The principles of heat transfer by conduction and convection may also be demonstrated. A list of equipment and supplies and the procedure for the experiment are presented.

  7. Thermal, optical, and electrical engineering of an innovative tunable white LED light engine

    NASA Astrophysics Data System (ADS)

    Trivellin, Nicola; Meneghini, Matteo; Ferretti, Marco; Barbisan, Diego; Dal Lago, Matteo; Meneghesso, Gaudenzio; Zanoni, Enrico

    2014-02-01

    Color temperature, intensity and blue spectrum of the light affects the ganglion receptors in human brain stimulating the human nervous system. With this work we review different methods for obtaining tunable light emission spectra and propose an innovative white LED lighting system. By an in depth study of the thermal, electrical and optical characteristics of GaN and GaP based compound semiconductors for optoelectronics a specific tunable spectra has been designed. The proposed tunable white LED system is able to achieve high CRI (above 95) in a large CCT range (3000 - 5000K).

  8. Teaching Innovation in High School Technology Classes

    ERIC Educational Resources Information Center

    Wright, Geoffrey A.; Skaggs, Paul; West, Richard E.

    2013-01-01

    Innovation is central to modern industry. It can and should be taught in schools. Not only does providing students a background in innovation benefit them later in life and industry, but it also promotes and further develops their critical thinking and collaboration skills. Despite the need for innovation, many have struggled with how to teach it.…

  9. Innovative methodologies and technologies for thermal energy release measurement.

    NASA Astrophysics Data System (ADS)

    Marotta, Enrica; Peluso, Rosario; Avino, Rosario; Belviso, Pasquale; Caliro, Stefano; Carandente, Antonio; Chiodini, Giovanni; Mangiacapra, Annarita; Petrillo, Zaccaria; Sansivero, Fabio; Vilardo, Giuseppe; Marfe, Barbara

    2016-04-01

    Volcanoes exchange heat, gases and other fluids between the interrior of the Earth and its atmosphere influencing processes both at the surface and above it. This work is devoted to improve the knowledge on the parameters that control the anomalies in heat flux and chemical species emissions associated with the diffuse degassing processes of volcanic and hydrothermal zones. We are studying and developing innovative medium range remote sensing technologies to measure the variations through time of heat flux and chemical emissions in order to boost the definition of the activity state of a volcano and allowing a better assessment of the related hazard and risk mitigation. The current methodologies used to measure heat flux (i.e. CO2 flux or temperature gradient) are either poorly efficient or effective, and are unable to detect short to medium time (days to months) variation trends in the heat flux. Remote sensing of these parameters will allow for measurements faster than already accredited methods therefore it will be both more effective and efficient in case of emergency and it will be used to make quick routine monitoring. We are currently developing a method based on drone-born IR cameras to measure the ground surface temperature that, in a purely conductive regime, is directly correlated to the shallow temperature gradient. The use of flying drones will allow to quickly obtain a mapping of areas with thermal anomalies and a measure of their temperature at distance in the order of hundreds of meters. Further development of remote sensing will be done through the use, on flying drones, of multispectral and/or iperspectral sensors, UV scanners in order to be able to detect the amount of chemical species released in the athmosphere.

  10. Building America Top Innovations 2012: Thermal Bypass Air Barriers in the 2009 International Energy Conservation Code

    SciTech Connect

    none,

    2013-01-01

    This Building America Top Innovations profile describes Building America research supporting Thermal Bypass Air Barrier requirements. Since these were adopted in the 2009 IECC, close to one million homes have been mandated to include this vitally important energy efficiency measure.

  11. High temperature solar thermal receiver

    NASA Technical Reports Server (NTRS)

    1979-01-01

    A design concept for a high temperature solar thermal receiver to operate at 3 atmospheres pressure and 2500 F outlet was developed. The performance and complexity of windowed matrix, tube-header, and extended surface receivers were evaluated. The windowed matrix receiver proved to offer substantial cost and performance benefits. An efficient and cost effective hardware design was evaluated for a receiver which can be readily interfaced to fuel and chemical processes or to heat engines for power generation.

  12. An innovative thermal system approach significantly increases system reliability and power and packaging densities

    SciTech Connect

    Burns, K.K.; Alexander, R.; Burns, J.R.

    1996-12-31

    An innovative self-contained active cooling system for electronic products, which increases power and packaging densities and improves reliability, was investigated. The cooling technology uses low cost, readily available, and reliable components. While this thermal control method can be applied to many applications, a simple power system cooling application will be demonstrated. The application demonstrates increased power density of a common 48 Vdc to 5Vdc high density DC-DC power converter module having standard dimensions of 2.4in.x4.6in.x0.5in. An increase in power density from 50W/in{sup 3} to over 80W/in{sup 3} was realized. In addition, significantly high calculated MTBF, from 300K hours to greater than 3M hours, was realized with low temperature operation.

  13. Innovative hybrid optics: combining the thermal stability of glass with low manufacturing cost of polymers

    NASA Astrophysics Data System (ADS)

    Doushkina, Valentina

    2010-08-01

    Innovative hybrid glass-polymer optical solutions on a component, module, or system level offer thermal stability of glass with low manufacturing cost of polymers reducing component weight, enhancing the safety and appeal of the products. Narrow choice of polymer materials is compensated by utilizing sophisticated optical surfaces such as refractive, reflective, and diffractive substrates with spherical, aspherical, cylindrical, and freeform prescriptions. Current advancements in polymer technology and injection molding capabilities placed polymer optics in the heart of many high tech devices and applications including Automotive Industry, Defense & Aerospace; Medical/Bio Science; Projection Displays, Sensors, Information Technology, Commercial and Industrial. This paper is about integration of polymer and glass optics for enhanced optical performance with reduced number of components, thermal stability, and low manufacturing cost. The listed advantages are not achievable when polymers or glass optics are used as stand-alone. The author demonstrates that integration of polymer and glass on component or optical system level on one hand offers high resolution and diffraction limited image quality, similar to the glass optics with stable refractive index and stable thermal performance when design is athermalized within the temperature range. On the other hand, the integrated hybrid solution significantly reduces cost, weight, and complexity, just like the polymer optics. The author will describe the design and analyzes process of combining glass and polymer optics for variety of challenging applications such as fast optics with low F/#, wide field of view lenses or systems, free form optics, etc.

  14. High thermal expansion, sealing glass

    DOEpatents

    Brow, R.K.; Kovacic, L.

    1993-11-16

    A glass composition is described for hermetically sealing to high thermal expansion materials such as aluminum alloys, stainless steels, copper, and copper/beryllium alloys, which includes between about 10 and about 25 mole percent Na[sub 2]O, between about 10 and about 25 mole percent K[sub 2]O, between about 5 and about 15 mole percent Al[sub 2]O[sub 3], between about 35 and about 50 mole percent P[sub 2]O[sub 5] and between about 5 and about 15 mole percent of one of PbO, BaO, and mixtures thereof. The composition, which may also include between 0 and about 5 mole percent Fe[sub 2]O[sub 3] and between 0 and about 10 mole percent B[sub 2]O[sub 3], has a thermal expansion coefficient in a range of between about 160 and 210[times]10[sup [minus]7]/C and a dissolution rate in a range of between about 2[times]10[sup [minus]7] and 2[times]10[sup [minus]9]g/cm[sup 2]-min. This composition is suitable to hermetically seal to metallic electrical components which will be subjected to humid environments over an extended period of time.

  15. High thermal expansion, sealing glass

    DOEpatents

    Brow, Richard K.; Kovacic, Larry

    1993-01-01

    A glass composition for hermetically sealing to high thermal expansion materials such as aluminum alloys, stainless steels, copper, and copper/beryllium alloys, which includes between about 10 and about 25 mole percent Na.sub.2 O, between about 10 and about 25 mole percent K.sub.2 O, between about 5 and about 15 mole percent Al.sub.2 O.sub.3, between about 35 and about 50 mole percent P.sub.2 O.sub.5 and between about 5 and about 15 mole percent of one of PbO, BaO, and mixtures thereof. The composition, which may also include between 0 and about 5 mole percent Fe.sub.2 O.sub.3 and between 0 and about 10 mole percent B.sub.2 O.sub.3, has a thermal expansion coefficient in a range of between about 160 and 210.times.10-7/.degree.C. and a dissolution rate in a range of between about 2.times.10.sup.- 7 and 2.times.10.sup.-9 g/cm.sup.2 -min. This composition is suitable to hermetically seal to metallic electrical components which will be subjected to humid environments over an extended period of time.

  16. Feasibility Study on Thermal-Hydraulic Performance of Innovative Water Reactor for Flexible Fuel Cycle (FLWR)

    SciTech Connect

    Akira, Ohnuki; Kazuyuki, Takase; Masatoshi, Kureta; Hiroyuki, Yoshida; Hidesada, Tamai; Wei, Liu; Toru, Nakatsuka; Takeharu, Misawa; Hajime, Akimoto

    2006-07-01

    R and D project to investigate thermal-hydraulic performance in tight-lattice rod bundles of Innovative Water Reactor for Flexible Fuel Cycle (FLWR) is started at Japan Atomic Energy Agency (JAEA) in collaboration with power company, reactor vendors, universities since 2002. The FLWR can attain the favorable characteristics such as effective utilization of uranium resources, multiple recycling of plutonium, high burn-up and long operation cycle, based on matured LWR technologies. MOX fuel assemblies with tight lattice arrangement are used to increase the conversion ratio by reducing the moderation of neutron. Increasing the in-core void fraction also contributes to the reduction of neutron moderation. The confirmation of thermal-hydraulic feasibility is one of the most important R and D items for the FLWR because of the tight lattice configuration. In this paper, we will show the R and D plan and summarize experimental studies. The experimental study is performed mainly using large-scale (37-rod bundle) test facility. Most important objective of the large-scale test is to resolve a fundamental subject whether the core cooling under a tight-lattice configuration is feasible. The characteristics of critical power and flow behavior are investigated under different geometrical configuration and boundary conditions. The configuration parameter is the gap between rods (FY2004) and the rod bowing (FY2005). We have confirmed the thermal-hydraulic feasibility from the experimental results. (authors)

  17. Building America Top Innovations 2012: High-R Walls

    SciTech Connect

    none,

    2013-01-01

    This Building America Top Innovations profile describes Building America research on high-R-value walls showing the difference between rated and whole wall R values and the need for vented cladding to reduce condensation potential with some insulation types.

  18. Value innovation: the strategic logic of high growth.

    PubMed

    Kim, W C; Mauborgne, R

    1997-01-01

    Why are some companies able to sustain high growth in revenues and profits--and others are not? To answer that question, the authors, both of INSEAD, spent five years studying more than 30 companies around the world. They found that the difference between the high-growth companies and their less successful competitors was in each group's assumptions about strategy. Managers of the less successful companies followed conventional strategic logic. Managers of the high-growth companies followed what the authors call the logic of value innovation. Conventional strategic logic and value innovation differ along the basic dimensions of strategy. Many companies take their industry's conditions as given; value innovators don't. Many companies let competitors set the parameters of their strategic thinking; value innovators do not use rivals as benchmarks. Rather than focus on the differences among customers, value innovators look for what customers value in common. Rather than view opportunities through the lens of existing assets and capabilities, value innovators ask, What if we start anew? The authors tell the story of the French hotelier Accor, which discarded the notion of what a hotel is supposed to look like in order to offer what most customers want: a good night's sleep at a low price. And Virgin Atlantic challenged industry conventions by eliminating first-class service and channeling savings into innovations for business-class passengers. Those companies didn't set out to build advantages over the competition, but they ended up achieving the greatest competitive advantages. PMID:10174449

  19. Innovative method for the thermal cycling of large spacecraft systems

    NASA Technical Reports Server (NTRS)

    Steimer, C. H.; Hale, A. D.

    1984-01-01

    The use of low cost, off the shelf prefabricated enclosures for spacecraft system thermal cycling applications was indicated. The enclosures are erected in the satellite integration areas without disturbing the test article, electrical test set, or RF interfaces. They are assembled by metal clad, modular urethane panels. These panels are self supporting, and are locked and sealed to each other on assembly. Penetrations for interconnecting cables, coaxial and waveguide services; and temperature conditioning inlet and outlet ducts are easily incorporated where required. The facility and its advantages and intrinsic benefits are described.

  20. Innovative space-saving device for high-temperature piping systems

    NASA Astrophysics Data System (ADS)

    Racki, Daniel J.

    1991-01-01

    Innovative, compact, simple piping supports have been developed for ultra-high-temperature nuclear and nonnuclear piping systems that require a large degree of structural reliability. These supports, originally designed for the SP-100 Ground Engineering System (GES) Nuclear Assembly Test (NAT) power system, can be used in both thin and thick wall piping systems. This paper discusses the design of these piping supports and the supporting thermal and structural analyses.

  1. In situ vitrification: An innovative thermal treatment technology

    SciTech Connect

    Fitzpatrick, V.F.; Timmerman, C.L.; Buelt, J.L.

    1987-03-01

    In situ vitrification is a thermal treatment process that converts contaminated soil into a chemically inert, stable glass and crystalline product. A square array of four electrodes are inserted into the ground to the desired treatment depth. Because the soil is not electrically conductive once the moisture has been driven off, a conductive mixture of flaked graphite and glass frit is placed among the electrodes to act as the starter path. An electrical potential is applied to the electrodes, which establishes an electrical current in the starter path. The resultant power heats the starter path and surrounding soil up to 3600F, well above the initial melting temperature or fusion temperature of soils. The normal fusion temperature of soil ranges between 2000 and 2500F. The graphite starter path is eventually consumed by oxidation, and the current is transferred to the molten soil, which is now electrically conductive. As the vitrified zone grows, it incorporates nonvolatile elements and destroys organic components by pyrolysis. The pyrolyzed byproducts migrate to the surface of the vitrified zone, where they combust in the presence of oxygen. A hood placed over the processing area provides confinement for the combustion gases, and the gases are drawn into the off-gas treatment system.

  2. The nuclear thermal electric rocket: a proposed innovative propulsion concept for manned interplanetary missions

    NASA Astrophysics Data System (ADS)

    Dujarric, C.; Santovincenzo, A.; Summerer, L.

    2013-03-01

    Conventional propulsion technology (chemical and electric) currently limits the possibilities for human space exploration to the neighborhood of the Earth. If farther destinations (such as Mars) are to be reached with humans on board, a more capable interplanetary transfer engine featuring high thrust, high specific impulse is required. The source of energy which could in principle best meet these engine requirements is nuclear thermal. However, the nuclear thermal rocket technology is not yet ready for flight application. The development of new materials which is necessary for the nuclear core will require further testing on ground of full-scale nuclear rocket engines. Such testing is a powerful inhibitor to the nuclear rocket development, as the risks of nuclear contamination of the environment cannot be entirely avoided with current concepts. Alongside already further matured activities in the field of space nuclear power sources for generating on-board power, a low level investigation on nuclear propulsion has been running since long within ESA, and innovative concepts have already been proposed at an IAF conference in 1999 [1, 2]. Following a slow maturation process, a new concept was defined which was submitted to a concurrent design exercise in ESTEC in 2007. Great care was taken in the selection of the design parameters to ensure that this quite innovative concept would in all respects likely be feasible with margins. However, a thorough feasibility demonstration will require a more detailed design including the selection of appropriate materials and the verification that these can withstand the expected mechanical, thermal, and chemical environment. So far, the predefinition work made clear that, based on conservative technology assumptions, a specific impulse of 920 s could be obtained with a thrust of 110 kN. Despite the heavy engine dry mass, a preliminary mission analysis using conservative assumptions showed that the concept was reducing the required

  3. Influence of thermal treatment on color, enzyme activities, and antioxidant capacity of innovative pastelike parsley products.

    PubMed

    Kaiser, Andrea; Brinkmann, Maike; Carle, Reinhold; Kammerer, Dietmar R

    2012-03-28

    Conventional spice powders are often characterized by low sensory quality and high microbial loads. Furthermore, genuine enzymes are only inhibited but not entirely inactivated upon drying, so that they may regain their activity upon rehydration of dried foods. To overcome these problems, initial heating was applied in the present study as the first process step for the production of innovative pastelike parsley products. For this purpose, fresh parsley was blanched (80, 90, and 100 °C for 1-10 min) and subsequently comminuted to form a paste. Alternatively, mincing was carried out prior to heat treatment. Regardless of temperature, the color of the latter product did not show any change after heating for 1 min. With progressing exposure time the green color turned to olive hues due to marked pheophytin formation. Inactivation of genuine peroxidase (POD) and polyphenol oxidase (PPO) was achieved at all temperature-time regimes applied. In contrast, the parsley products obtained after immediate water-blanching were characterized by brighter green colors and enhanced pigment retention. With the exception of the variants water-blanched at 80 °C, POD and PPO were completely inactivated at any of the thermal treatments. Furthermore, in water-blanched samples, antioxidant capacities as determined by the TEAC and FRAP assays were even enhanced compared to unheated parsley, whereas a decrease of phenolic contents could not be prevented. Consequently, the innovative process presented in this study allows the production of novel herb and spice products characterized by improved sensory quality as compared to conventional spice products. PMID:22375822

  4. High Spatial Resolution Thermal Satellite Technologies

    NASA Technical Reports Server (NTRS)

    Ryan, Robert

    2003-01-01

    This document in the form of viewslides, reviews various low-cost alternatives to high spatial resolution thermal satellite technologies. There exists no follow-on to Landsat 7 or ASTER high spatial resolution thermal systems. This document reviews the results of the investigation in to the use of new technologies to create a low-cost useful alternative. Three suggested technologies are examined. 1. Conventional microbolometer pushbroom modes offers potential for low cost Landsat Data Continuity Mission (LDCM) thermal or ASTER capability with at least 60-120 ground sampling distance (GSD). 2. Backscanning could produce MultiSpectral Thermal Imager performance without cooled detectors. 3. Cooled detector could produce hyperspectral thermal class system or extremely high spatial resolution class instrument.

  5. Thermal disconnect for high-temperature batteries

    DOEpatents

    Jungst, Rudolph George; Armijo, James Rudolph; Frear, Darrel Richard

    2000-01-01

    A new type of high temperature thermal disconnect has been developed to protect electrical and mechanical equipment from damage caused by operation at extreme temperatures. These thermal disconnects allow continuous operation at temperatures ranging from 250.degree. C. to 450.degree. C., while rapidly terminating operation at temperatures 50.degree. C. to 150.degree. C. higher than the continuous operating temperature.

  6. High intensity, pulsed thermal neutron source

    DOEpatents

    Carpenter, J.M.

    1973-12-11

    This invention relates to a high intensity, pulsed thermal neutron source comprising a neutron-producing source which emits pulses of fast neutrons, a moderator block adjacent to the last neutron source, a reflector block which encases the fast neutron source and the moderator block and has a thermal neutron exit port extending therethrough from the moderator block, and a neutron energy- dependent decoupling reflector liner covering the interior surfaces of the thermal neutron exit port and surrounding all surfaces of the moderator block except the surface viewed by the thermal neutron exit port. (Official Gazette)

  7. Successful Magnet High Schools. Innovations in Education

    ERIC Educational Resources Information Center

    US Department of Education, 2008

    2008-01-01

    Lack of relevant course work is a top reason why high school students drop out, and studies have shown that low-income and minority students are less likely to be enrolled in college preparatory curricula than their more affluent peers. In today's world, it is critical to ensure that all students have access to a rigorous, high-quality education…

  8. High Reynolds Number Thermal Stability Experiments

    NASA Technical Reports Server (NTRS)

    Emens, Jessica M.; Brown, Sarah P.; Frederick Robert A., Jr.; Wood, A. John

    2004-01-01

    This work represents preliminary thermal stability results for liquid hydrocarbon fuels. High Reynolds Number Thermal Stability experiments with Jet A and RP-1 resulted in a quantitative measurement of the thermal stability. Each fuel flowed through a heated capillary tube that held the outlet temperature at 290 C. An optical pyrometer measured the surface temperature of the tube at 12 locations as a function of time. The High Reynolds Number Thermal Stability number was then determined using standards published by the American Society for Testing and Materials. The results for Jet A showed lower thermal stability than similar tests conducted at another facility. The RP-1 results are the first reported using this technique. Because the temperature rise on the capillary tube during testing for the RP-1 fuels was not significant, a new standard for the testing conditions should be developed for these types of fuels.

  9. Innovations in high-temperature particulate filtration

    SciTech Connect

    Lippert, T.

    1997-05-01

    Fluidized-bed combustion and coal gasification expose sensitive equipment, such as high-speed turbines, to hot combustion offgases. In order to prevent erosion, corrosion, and other damage to sensitive equipment, such systems now incorporate high-temperature particulate filters. One device often considered for such applications uses a design similar to a baghouse (i.e., multiple banks of porous filter bags that remove particulate from gas streams). In this case, however, instead of polyester or teflon fabric, the filter elements are made of rigid ceramic or similar materials. These devices are sometimes called `candle filters,` and the individual ceramic filter elements are frequently called `candles.` Three high-temperature applications of candle filters are described here. 2 refs., 3 figs.

  10. Innovative thermal energy harvesting for future autonomous applications

    NASA Astrophysics Data System (ADS)

    Monfray, Stephane

    2013-12-01

    As communicating autonomous systems market is booming, the role of energy harvesting will be a key enabler. As example, heat is one of the most abundant energy sources that can be converted into electricity in order to power circuits. Harvesting systems that use wasted heat open new ways to power autonomous sensors when the energy consumption is low, or to create systems of power generators when the conversion efficiency is high. The combination of different technologies (low power μ-processors, μ-batteries, radio, sensors...) with new energy harvesters compatible with large varieties of use-cases with allow to address this booming market. Thanks to the conjunction of ultra-low power electronic development, 3D technologies & Systems in Package approaches, the integration of autonomous sensors and electronics with ambient energy harvesting will be achievable. The applications are very wide, from environment and industrial sensors to medical portable applications, and the Internet of things may also represent in the future a several billions units market.

  11. Innovations in high power fiber laser applications

    NASA Astrophysics Data System (ADS)

    Beyer, Eckhard; Mahrle, Achim; Lütke, Matthias; Standfuss, Jens; Brückner, Frank

    2012-02-01

    Diffraction-limited high power lasers represent a new generation of lasers for materials processing, characteristic traits of which are: smaller, cost-effective and processing "on the fly". Of utmost importance is the high beam quality of fiber lasers which enables us to reduce the size of the focusing head incl. scanning mirrors. The excellent beam quality of the fiber laser offers a lot of new applications. In the field of remote cutting and welding the beam quality is the key parameter. By reducing the size of the focusing head including the scanning mirrors we can reach scanning frequencies up to 1.5 kHz and in special configurations up to 4 kHz. By using these frequencies very thin and deep welding seams can be generated experienced so far with electron beam welding only. The excellent beam quality of the fiber laser offers a high potential for developing new applications from deep penetration welding to high speed cutting. Highly dynamic cutting systems with maximum speeds up to 300 m/min and accelerations up to 4 g reduce the cutting time for cutting complex 2D parts. However, due to the inertia of such systems the effective cutting speed is reduced in real applications. This is especially true if complex shapes or contours are cut. With the introduction of scanner-based remote cutting systems in the kilowatt range, the effective cutting speed on the contour can be dramatically increased. The presentation explains remote cutting of metal foils and sheets using high brightness single mode fiber lasers. The presentation will also show the effect of optical feedback during cutting and welding with the fiber laser, how those feedbacks could be reduced and how they have to be used to optimize the cutting or welding process.

  12. Interactive Leadership in High School Innovation.

    ERIC Educational Resources Information Center

    Clarke, John; Aiken, Judith A.; Sullivan, Mary J.

    1999-01-01

    Every year, a Vermont high school teacher uses laws of physics to teach students how to design, field test, and calibrate a weapon that fires tennis balls to 100-yard distances. This article explains how the "physics war" grew to accommodate the new Vermont curriculum standards at various organizational levels. (22 references) (MLH)

  13. Factors Supporting or Inhibiting Innovative Practices in Senior High Schools.

    ERIC Educational Resources Information Center

    Daresh, John C.

    Semistructured interviews were used to query school staffs, administrators, and school board members in this exploratory field study of successful high schools implementing an individualized program. Analysis of results suggest these possible findings regarding factors that may support or inhibit the implementation of innovations: (1) The most…

  14. Information support for high technologies: issues of innovation

    NASA Astrophysics Data System (ADS)

    Piskorskaya, S. Yu; Goncharov, A. E.; Prohorovich, G. A.; Perantseva, A. V.

    2016-04-01

    The current development of high technologies and innovative projects requires systematic information support. This article describes examples of information support and promotion of regional technological platforms of the Krasnoiarskii krai on the base of communications projects which are being realized by students at SibSAU. These technological platforms correspond to the prioritized fields of developing science and research in the Russian Federation.

  15. Polyethylene nanofibres with very high thermal conductivities.

    PubMed

    Shen, Sheng; Henry, Asegun; Tong, Jonathan; Zheng, Ruiting; Chen, Gang

    2010-04-01

    Bulk polymers are generally regarded as thermal insulators, and typically have thermal conductivities on the order of 0.1 W m(-1) K(-1). However, recent work suggests that individual chains of polyethylene--the simplest and most widely used polymer--can have extremely high thermal conductivity. Practical applications of these polymers may also require that the individual chains form fibres or films. Here, we report the fabrication of high-quality ultra-drawn polyethylene nanofibres with diameters of 50-500 nm and lengths up to tens of millimetres. The thermal conductivity of the nanofibres was found to be as high as approximately 104 W m(-1) K(-1), which is larger than the conductivities of about half of the pure metals. The high thermal conductivity is attributed to the restructuring of the polymer chains by stretching, which improves the fibre quality toward an 'ideal' single crystalline fibre. Such thermally conductive polymers are potentially useful as heat spreaders and could supplement conventional metallic heat-transfer materials, which are used in applications such as solar hot-water collectors, heat exchangers and electronic packaging. PMID:20208547

  16. High precision innovative micropump for artificial pancreas

    NASA Astrophysics Data System (ADS)

    Chappel, E.; Mefti, S.; Lettieri, G.-L.; Proennecke, S.; Conan, C.

    2014-03-01

    The concept of artificial pancreas, which comprises an insulin pump, a continuous glucose meter and a control algorithm, is a major step forward in managing patient with type 1 diabetes mellitus. The stability of the control algorithm is based on short-term precision micropump to deliver rapid-acting insulin and to specific integrated sensors able to monitor any failure leading to a loss of accuracy. Debiotech's MEMS micropump, based on the membrane pump principle, is made of a stack of 3 silicon wafers. The pumping chamber comprises a pillar check-valve at the inlet, a pumping membrane which is actuated against stop limiters by a piezo cantilever, an anti-free-flow outlet valve and a pressure sensor. The micropump inlet is tightly connected to the insulin reservoir while the outlet is in direct communication with the patient skin via a cannula. To meet the requirement of a pump dedicated to closed-loop application for diabetes care, in addition to the well-controlled displacement of the pumping membrane, the high precision of the micropump is based on specific actuation profiles that balance effect of pump elasticity in low-consumption push-pull mode.

  17. High precision thermal neutron detectors

    SciTech Connect

    Radeka, V.; Schaknowski, N.A.; Smith, G.C.; Yu, B.

    1994-12-31

    Two-dimensional position sensitive detectors are indispensable in neutron diffraction experiments for determination of molecular and crystal structures in biology, solid-state physics and polymer chemistry. Some performance characteristics of these detectors are elementary and obvious, such as the position resolution, number of resolution elements, neutron detection efficiency, counting rate and sensitivity to gamma-ray background. High performance detectors are distinguished by more subtle characteristics such as the stability of the response (efficiency) versus position, stability of the recorded neutron positions, dynamic range, blooming or halo effects. While relatively few of them are needed around the world, these high performance devices are sophisticated and fairly complex, their development requires very specialized efforts. In this context, we describe here a program of detector development, based on {sup 3}He filled proportional chambers, which has been underway for some years at the Brookhaven National Laboratory. Fundamental approaches and practical considerations are outlined that have resulted in a series of high performance detectors with the best known position resolution, position stability, uniformity of response and reliability over time, for devices of this type.

  18. Innovative Field Emitters for High-Voltage Electronic Devices

    NASA Astrophysics Data System (ADS)

    Sominski, G. G.; Sezonov, V. E.; Taradaev, E. P.; Tumareva, T. A.; Zadiranov, Yu. M.; Kornishin, S. Yu.; Stepanova, A. N.

    2015-12-01

    We describe multitip field emitters with protective coatings, which were developed in Peter the Great St. Petersburg Polytechnic University. The coatings ensure long-term operation of the emitters under high currents and technical vacuum. Innovative multi-layer emitters composed of contacting nanolayers of materials with different work functions are presented as well. The possibility by using the developed emitters in high-voltage electronic devices is demonstrated.

  19. High thermal conductivity connector having high electrical isolation

    DOEpatents

    Nieman, Ralph C.; Gonczy, John D.; Nicol, Thomas H.

    1995-01-01

    A method and article for providing a low-thermal-resistance, high-electrical-isolation heat intercept connection. The connection method involves clamping, by thermal interference fit, an electrically isolating cylinder between an outer metallic ring and an inner metallic disk. The connection provides durable coupling of a heat sink and a heat source.

  20. Innovative nuclear thermal propulsion technology evaluation - Results of the NASA/DOE task team study

    NASA Technical Reports Server (NTRS)

    Howe, Steven D.; Borowski, Stanley; Motloch, Chet; Helms, Ira; Diaz, Nils; Anghaie, Samim; Latham, Thomas

    1991-01-01

    In response to findings from two NASA/DOE nuclear propulsion workshops, six task teams were created to continue evaluation of various propulsion concepts, from which evolved an innovative concepts subpanel to evaluate thermal propulsion concepts which did not utilize solid fuel. This subpanel endeavored to evaluate each concept on a level technology basis, and to identify critical issues, technologies, and early proof-of-concept experiments. Results of the concept studies including the liquid core fission, the gas core fission, the fission foil reactors, explosively driven systems, fusion, and antimatter are presented.

  1. High-Temperature Adhesives for Thermally Stable Aero-Assist Technologies

    NASA Technical Reports Server (NTRS)

    Eberts, Kenneth; Ou, Runqing

    2013-01-01

    Aero-assist technologies are used to control the velocity of exploration vehicles (EVs) when entering Earth or other planetary atmospheres. Since entry of EVs in planetary atmospheres results in significant heating, thermally stable aero-assist technologies are required to avoid the high heating rates while maintaining low mass. Polymer adhesives are used in aero-assist structures because of the need for high flexibility and good bonding between layers of polymer films or fabrics. However, current polymer adhesives cannot withstand temperatures above 400 C. This innovation utilizes nanotechnology capabilities to address this need, leading to the development of high-temperature adhesives that exhibit high thermal conductivity in addition to increased thermal decomposition temperature. Enhanced thermal conductivity will help to dissipate heat quickly and effectively to avoid temperature rising to harmful levels. This, together with increased thermal decomposition temperature, will enable the adhesives to sustain transient high-temperature conditions.

  2. Innovative nuclear thermal propulsion technology evaluation: Results of the NASA/DOE Task Team study

    SciTech Connect

    Howe, S. ); Borowski, S. . Lewis Research Center); Motloch, C. ); Helms, I. ); Diaz, N.; Anghaie, S. ); Latham, T. (United

    1991-01-01

    In response to findings from two NASA/DOE nuclear propulsion workshops held in the summer of 1990, six task teams were formed to continue evaluation of various nuclear propulsion concepts. The Task Team on Nuclear Thermal Propulsion (NTP) created the Innovative Concepts Subpanel to evaluate thermal propulsion concepts which did not utilize solid fuel. The Subpanel endeavored to evaluate each of the concepts on a level technological playing field,'' and to identify critical technologies, issues, and early proof-of-concept experiments. The concepts included the liquid core fission, the gas core fission, the fission foil reactors, explosively driven systems, fusion, and antimatter. The results of the studies by the panel will be provided. 13 refs., 6 figs., 2 tabs.

  3. Advanced Metal-Hydrides-Based Thermal Battery: A New Generation of High Density Thermal Battery Based on Advanced Metal Hydrides

    SciTech Connect

    2011-12-01

    HEATS Project: The University of Utah is developing a compact hot-and-cold thermal battery using advanced metal hydrides that could offer efficient climate control system for EVs. The team’s innovative designs of heating and cooling systems for EVs with high energy density, low-cost thermal batteries could significantly reduce the weight and eliminate the space constraint in automobiles. The thermal battery can be charged by plugging it into an electrical outlet while charging the electric battery and it produces heat and cold through a heat exchanger when discharging. The ultimate goal of the project is a climate-controlling thermal battery that can last up to 5,000 charge and discharge cycles while substantially increasing the driving range of EVs, thus reducing the drain on electric batteries.

  4. Thermal modeling of high efficiency AMTEC cells

    SciTech Connect

    Ivanenok, J.F. III; Sievers, R.K.; Crowley, C.J.

    1995-12-31

    Remotely condensed Alkali Metal Thermal to Electric Conversion (AMTEC) cells achieve high efficiency by thermally isolating the hot {beta} Alumina Solid Electrolyte (BASE) tube from the cold condensing region. In order to design high efficiency AMTEC cells the designer must understand the heat losses associated with the AMTEC process. The major parasitic heat losses are due to conduction and radiation, and significant coupling of the two mechanisms occurs. This paper describes an effort to characterize the thermal aspects of the model PL-6 AMTEC cell and apply this understanding to the design of a higher efficiency AMTEC cell, model PL-8. Two parallel analyses were used to model the thermal characteristics of PL-6. The first was a lumped node model using the classical electric circuit analogy and the second was a detailed finite-difference model. The lumped node model provides high speed and reasonable accuracy, and the detailed finite-difference model provides a more accurate, as well as visual, description of the cell temperature profiles. The results of the two methods are compared to the as-measured PL-6 data. PL-6 was the first cell to use a micromachined condenser to lower the radiation losses to the condenser, and it achieved a conversion efficiency of 15% (3 W output/20 W Input) at a temperature of 1050 K.

  5. High-performance flat-panel solar thermoelectric generators with high thermal concentration.

    PubMed

    Kraemer, Daniel; Poudel, Bed; Feng, Hsien-Ping; Caylor, J Christopher; Yu, Bo; Yan, Xiao; Ma, Yi; Wang, Xiaowei; Wang, Dezhi; Muto, Andrew; McEnaney, Kenneth; Chiesa, Matteo; Ren, Zhifeng; Chen, Gang

    2011-07-01

    The conversion of sunlight into electricity has been dominated by photovoltaic and solar thermal power generation. Photovoltaic cells are deployed widely, mostly as flat panels, whereas solar thermal electricity generation relying on optical concentrators and mechanical heat engines is only seen in large-scale power plants. Here we demonstrate a promising flat-panel solar thermal to electric power conversion technology based on the Seebeck effect and high thermal concentration, thus enabling wider applications. The developed solar thermoelectric generators (STEGs) achieved a peak efficiency of 4.6% under AM1.5G (1 kW m(-2)) conditions. The efficiency is 7-8 times higher than the previously reported best value for a flat-panel STEG, and is enabled by the use of high-performance nanostructured thermoelectric materials and spectrally-selective solar absorbers in an innovative design that exploits high thermal concentration in an evacuated environment. Our work opens up a promising new approach which has the potential to achieve cost-effective conversion of solar energy into electricity. PMID:21532584

  6. Thermal interface pastes nanostructured for high performance

    NASA Astrophysics Data System (ADS)

    Lin, Chuangang

    Thermal interface materials in the form of pastes are needed to improve thermal contacts, such as that between a microprocessor and a heat sink of a computer. High-performance and low-cost thermal pastes have been developed in this dissertation by using polyol esters as the vehicle and various nanoscale solid components. The proportion of a solid component needs to be optimized, as an excessive amount degrades the performance, due to the increase in the bond line thickness. The optimum solid volume fraction tends to be lower when the mating surfaces are smoother, and higher when the thermal conductivity is higher. Both a low bond line thickness and a high thermal conductivity help the performance. When the surfaces are smooth, a low bond line thickness can be even more important than a high thermal conductivity, as shown by the outstanding performance of the nanoclay paste of low thermal conductivity in the smooth case (0.009 mum), with the bond line thickness less than 1 mum, as enabled by low storage modulus G', low loss modulus G" and high tan delta. However, for rough surfaces, the thermal conductivity is important. The rheology affects the bond line thickness, but it does not correlate well with the performance. This study found that the structure of carbon black is an important parameter that governs the effectiveness of a carbon black for use in a thermal paste. By using a carbon black with a lower structure (i.e., a lower DBP value), a thermal paste that is more effective than the previously reported carbon black paste was obtained. Graphite nanoplatelet (GNP) was found to be comparable in effectiveness to carbon black (CB) pastes for rough surfaces, but it is less effective for smooth surfaces. At the same filler volume fraction, GNP gives higher thermal conductivity than carbon black paste. At the same pressure, GNP gives higher bond line thickness than CB (Tokai or Cabot). The effectiveness of GNP is limited, due to the high bond line thickness. A

  7. Thermal fuse for high-temperature batteries

    DOEpatents

    Jungst, Rudolph G.; Armijo, James R.; Frear, Darrel R.

    2000-01-01

    A thermal fuse, preferably for a high-temperature battery, comprising leads and a body therebetween having a melting point between approximately 400.degree. C. and 500.degree. C. The body is preferably an alloy of Ag--Mg, Ag--Sb, Al--Ge, Au--In, Bi--Te, Cd--Sb, Cu--Mg, In--Sb, Mg--Pb, Pb--Pd, Sb--Zn, Sn--Te, or Mg--Al.

  8. Charter Schools and Innovation: The High Tech High Model

    ERIC Educational Resources Information Center

    Neumann, Richard

    2008-01-01

    This article examines the High Tech High charter school, the ideas and practices that influenced its development, and the school's impact on San Diego Unified School District, which authorized the charter. The Discussion analyzes the school's program using frameworks of social bonding theory and progressive educational theory and practice. Since…

  9. Another Innovation from High Tech High--Embedded Teacher Training

    ERIC Educational Resources Information Center

    Griswold, Janie; Riordan, Rob

    2016-01-01

    High Tech High School's teaching internship program blends on-the-job work with classroom theory. Interns spend two years working as full teachers as they take courses. The program serves three large purposes: Train new teachers and build capacity in the HTH organization; train teachers in and beyond HTH for success in a wide range of contexts;…

  10. Innovative Phase Change Thermal Energy Storage Solution for Baseload Power Phase 1 Final Report

    SciTech Connect

    Qiu, Songgang

    2013-05-15

    The primary purpose of this project is to develop and validate an innovative, scalable phase change salt thermal energy storage (TES) system that can interface with Infinia’s family of free-piston Stirling engines (FPSE). This TES technology is also appropriate for Rankine and Brayton power converters. Solar TES systems based on latent heat of fusion rather than molten salt temperature differences, have many advantages that include up to an order of magnitude higher energy storage density, much higher temperature operation, and elimination of pumped loops for most of Infinia’s design options. DOE has funded four different concepts for solar phase change TES, including one other Infinia awarded project using heat pipes to transfer heat to and from the salt. The unique innovation in this project is an integrated TES/pool boiler heat transfer system that is the simplest approach identified to date and arguably has the best potential for minimizing the levelized cost of energy (LCOE). The Phase 1 objectives are to design, build and test a 1-hour TES proof-of-concept lab demonstrator integrated with an Infinia 3 kW Stirling engine, and to conduct a preliminary design of a 12-hour TES on-sun prototype.

  11. Safety improvements in high pressure thermal machines

    SciTech Connect

    Otters, J.L.

    1988-02-09

    In a thermal machine of the type including a machine body having a main axis extending between a thermal end and a work end, a working fluid at relatively high pressure in a working fluid chamber defined in the body and a displacer element reciprocable within the chamber for subjecting the fluid to a thermodynamic cycle in cooperation with a reciprocable work piston, the improvement is described comprising outer shell means enclosing the machine body for maintaining a substantially sealed atmosphere about the machine body, and diffuser means arranged between the machine body and the outer shell means for diffusing a shock wave traveling towards the outer shell means resulting from explosive failure of the machine body and for shielding the outer shell means against fragments projected upon such failure.

  12. Reservoir modeling of the Solvent Thermal Resource Innovation Process for enhanced oil recovery

    NASA Astrophysics Data System (ADS)

    James, S. C.; Lucia, A.; Voskov, D.; Schneider, A.

    2012-12-01

    The Automatic Differentiation General Purpose Research Simulator (ADGPRS) has been improved to more accurately simulate multiphase, multi-component flow in porous media. ADGPRS has been augmented with a general, multi-scale framework for multi-component, multi-phase equilibrium flash calculations, which uses information at the molecular and bulk fluid length scales. The key attributes of this multi-scale Gibbs-Helmholtz Constrained Equation of State (GHC EOS) approach are (1) the use of coarse-grained, fixed-particle, temperature, and pressure Monte Carlo simulations to gather pure component internal energies of departure, (2) a linear mixing rule for internal energies of departure for mixtures, (3) a novel expression for partial fugacity coefficients, and (4) a flash algorithm based on complex-valued compressibility factors and densities to assist in phase existence determination. Our thermal nonlinear formulation for solution of reservoir equations is based on saturations and phase concentrations and uses variable substitution to handle phase appearances and disappearances in systems with an arbitrary number of phases. This coupled ADGPRS-GHC framework simulates multi-component, thermal flow at equilibrium conditions, which is important for modeling thermally enhanced oil recovery including steam and CO2 co-solvent injection. The coupled code is applied to an example problem where heat and mass (steam and CO2) are added to a "depleted" oil-bearing formation. Results demonstrate the improved efficiency of the Solvent Thermal Resource Innovation Process (STRIP) oil recovery method over standard steam injection without CO2. Also, STRIP operating parameters are optimized based on simulation results.

  13. Innovative Application of Maintenance-Free Phase-Change Thermal Energy Storage for Dish-Engine Solar Power Generation

    SciTech Connect

    Qui, Songgang; Galbraith, Ross

    2013-01-23

    This final report summarizes the final results of the Phase II Innovative Application of Maintenance-Free Phase-Change Thermal Energy Storage for Dish-Engine Solar Power Generation project being performed by Infinia Corporation for the U.S. Department of Energy under contract DE-FC36-08GO18157 during the project period of September 1, 2009 - August 30, 2012. The primary objective of this project is to demonstrate the practicality of integrating thermal energy storage (TES) modules, using a suitable thermal salt phase-change material (PCM) as its medium, with a dish/Stirling engine; enabling the system to operate during cloud transients and to provide dispatchable power for 4 to 6 hours after sunset. A laboratory prototype designed to provide 3 kW-h of net electrical output was constructed and tested at Infinia's Ogden Headquarters. In the course of the testing, it was determined that the system's heat pipe network - used to transfer incoming heat from the solar receiver to both the Stirling generator heater head and to the phase change salt - did not perform to expectations. The heat pipes had limited capacity to deliver sufficient heat energy to the generator and salt mass while in a charging mode, which was highly dependent on the orientation of the device (vertical versus horizontal). In addition, the TES system was only able to extract about 30 to 40% of the expected amount of energy from the phase change salt once it was fully molten. However, the use of heat pipes to transfer heat energy to and from a thermal energy storage medium is a key technical innovation, and the project team feels that the limitations of the current device could be greatly improved with further development. A detailed study of manufacturing costs using the prototype TES module as a basis indicates that meeting DOE LCOE goals with this hardware requires significant efforts. Improvement can be made by implementing aggressive cost-down initiatives in design and materials, improving system

  14. Development and Testing of an Innovative Two-Arm Focal-Plane Thermal Strap (TAFTS)

    NASA Technical Reports Server (NTRS)

    Urquiza, E.; Vasquez, C.; Rodriguez, J.; Van Gorp, B.

    2011-01-01

    Maintaining temperature stability in optical focal planes comes with the intrinsic challenge of creating a pathway that is both extremely flexible mechanically and highly conductive thermally. The task is further complicated because science-caliber optical focal planes are extremely delicate, yet their mechanical resiliency is rarely tested and documented. The mechanical engineer tasked with the thermo-mechanical design must then create a highly conductive thermal link that minimizes the tensile and shear stresses transmitted to the focal plane without design parameters on an acceptable stiffness. This paper will describe the development and testing of the thermal link developed for the Portable Remote Imaging Spectrometer (PRISM) instrument. It will provide experimentally determined mechanical stiffness plots in the three axes of interest. Analytical and experimental thermal conductance results for the two-arm focal-plane thermal strap (TAFTS), from cryogenic to room temperatures, are also presented. The paper also briefly describes some elements of the fabrication process followed in developing a novel design solution, which provides high conductance and symmetrical mechanical loading, while providing enhanced flexibility in all three degrees of freedom.

  15. Development of a high force thermal latch

    NASA Astrophysics Data System (ADS)

    Nygren, William D.

    1995-05-01

    This paper describes the preliminary development of a high force thermal latch (HFTL). The HFTL has one moving part which is restrained in the latched position by a low melting temperature or fusible metal alloy. When heated the fusible alloy flows to a receiving chamber and in so doing at first releases the tension load in the latch bolt and later releases the bolt itself. The HFTL can be used in place of pyrotechnically activated spacecraft release devices in those instances where the elimination of both pyrotechnic shock-loading and rapid strain-energy release take precedence over the near instantaneous release offered by ordnance initiated devices.

  16. Development of a high force thermal latch

    NASA Technical Reports Server (NTRS)

    Nygren, William D.

    1995-01-01

    This paper describes the preliminary development of a high force thermal latch (HFTL). The HFTL has one moving part which is restrained in the latched position by a low melting temperature or fusible metal alloy. When heated the fusible alloy flows to a receiving chamber and in so doing at first releases the tension load in the latch bolt and later releases the bolt itself. The HFTL can be used in place of pyrotechnically activated spacecraft release devices in those instances where the elimination of both pyrotechnic shock-loading and rapid strain-energy release take precedence over the near instantaneous release offered by ordnance initiated devices.

  17. Advanced Liquid-Cooling Garment Using Highly Thermally Conductive Sheets

    NASA Technical Reports Server (NTRS)

    Ruemmele, Warren P.; Bue, Grant C.; Orndoff, Evelyne; Tang, Henry

    2010-01-01

    This design of the liquid-cooling garment for NASA spacesuits allows the suit to remove metabolic heat from the human body more effectively, thereby increasing comfort and performance while reducing system mass. The garment is also more flexible, with fewer restrictions on body motion, and more effectively transfers thermal energy from the crewmember s body to the external cooling unit. This improves the garment s performance in terms of the maximum environment temperature in which it can keep a crewmember comfortable. The garment uses flexible, highly thermally conductive sheet material (such as graphite), coupled with cooling water lines of improved thermal conductivity to transfer the thermal energy from the body to the liquid cooling lines more effectively. The conductive sheets can be layered differently, depending upon the heat loads, in order to provide flexibility, exceptional in-plane heat transfer, and good through-plane heat transfer. A metal foil, most likely aluminum, can be put between the graphite sheets and the external heat source/sink in order to both maximize through-plane heat transfer at the contact points, and to serve as a protection to the highly conductive sheets. Use of a wicking layer draws excess sweat away from the crewmember s skin and the use of an outer elastic fabric ensures good thermal contact of the highly conductive underlayers with the skin. This allows the current state of the art to be improved by having cooling lines that can be more widely spaced to improve suit flexibility and to reduce weight. Also, cooling liquid does not have to be as cold to achieve the same level of cooling. Specific areas on the human body can easily be targeted for greater or lesser cooling to match human physiology, a warmer external environment can be tolerated, and spatial uniformity of the cooling garment can be improved to reduce vasoconstriction limits. Elements of this innovation can be applied to other embodiments to provide effective heat

  18. Influence of High Cycle Thermal Loads on Thermal Fatigue Behavior of Thick Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Miller, Robert A.

    1997-01-01

    Thick thermal barrier coating systems in a diesel engine experience severe thermal Low Cycle Fatigue (LCF) and High Cycle Fatigue (HCF) during engine operation. In the present study, the mechanisms of fatigue crack initiation and propagation, as well as of coating failure, under thermal loads which simulate engine conditions, are investigated using a high power CO2 laser. In general, surface vertical cracks initiate early and grow continuously under LCF and HCF cyclic 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, which induce tensile stresses in the coating after cooling. Experiments show that the HCF cycles are very damaging to the coating systems. The combined LCF and HCF tests produced more severe coating surface cracking, microspallation and accelerated crack growth, as compared to the pure LCF test. It is suggested that the HCF component cannot only accelerate the surface crack initiation, but also interact with the LCF by contributing to the crack growth at high temperatures. The increased LCF stress intensity at the crack tip due to the HCF component enhances the subsequent LCF crack growth. Conversely, since a faster HCF crack growth rate will be expected with lower effective compressive stresses in the coating, the LCF cycles also facilitate the HCF crack growth at high temperatures by stress relaxation process. A surface wedging model has been proposed to account for the HCF crack growth in the coating system. This mechanism predicts that HCF damage effect increases with increasing temperature swing, the thermal expansion coefficient and the elastic modulus of the ceramic coating, as well as the HCF interacting depth. A good agreement has been found between the analysis and experimental evidence.

  19. Thermal Conductivity of Argon at High Pressures and High Temperatures

    NASA Astrophysics Data System (ADS)

    Wong, M. L.; Goncharov, A. F.; Dalton, D. A.; Ojwang, J.; Struzhkin, V.; Konopkova, Z.; Lazor, P.

    2010-12-01

    Accurate data on the thermal conductivity of argon at high pressures and high temperatures is essential to unraveling the nature of the Earth’s interior. Argon is a common pressure-transmitting medium in diamond anvil cell (DAC) experiments, which is commonly used for studying the properties of minerals at pressures and temperatures native to the mantel and core. We used a transient heating technique (Beck et al., 2007) in a symmetric DAC up to 50 GPa and 2500 K. A thin iridium foil (1 μm thick) positioned in a recessed gasket hole filled with argon served as a heat absorber (coupler) to pump thermal energy into the sample. We used 6 μs width pulses from electronically modulated Yb-based fiber laser. We determined the temperature of the coupler with 500 ns time resolution by applying the Planck function to its thermal emission spectrum, and doing this over time yields temperature verses time for the coupler. Using finite element (FE) calculation methods we simulated the heat flux transfer in the DAC cavity using the experimentally determined geometric and laser heating parameters. The thermochemical parameters of Ir and Ar were determined by scaling the ambient pressure data using the available equations of state. The temperature dependent thermal conductivity of Ar was determined by fitting the results of FE calculations to the experimentally determined time dependent coupler temperature. We used the results of the theoretical calculations (Tretiakov & Scandolo, 2004) as the initial input. The results for the pressure and temperature dependent thermal conductivity of Ar will be reported at the meeting. This work is supported by NSF EAR 0711358, NSF-REU, Carnegie Institution of Washington, and DOE-NNSA (CDAC). Beck, P; Goncharov, A.F., Struzhkin, V.V., Militzer, B, Mao, H.K, Hemley, R.J. (2007). Measurement of thermal diffusivity at high pressure using a transient heating technique, Appl Phys. Lett. 91, 181914-(1-3). Tretiakov, K. V. & S. Scandolo (2004

  20. High Cycle Thermal Fatigue in French PWR

    SciTech Connect

    Blondet, Eric; Faidy, Claude

    2002-07-01

    Different fatigue-related incidents which occurred in the world on the auxiliary lines of the reactor coolant system (SIS, RHR, CVC) have led EDF to search solutions in order to avoid or to limit consequences of thermodynamic phenomenal (Farley-Tihange, free convection loop and stratification, independent thermal cycling). Studies are performed on mock-up and compared with instrumentation on nuclear power stations. At the present time, studies allow EDF to carry out pipe modifications and to prepare specifications and recommendations for next generation of nuclear power plants. In 1998, a new phenomenal appeared on RHR system in Civaux. A crack was discovered in an area where hot and cold fluids (temperature difference of 140 deg. C) were mixed. Metallurgic studies concluded that this crack was caused by high cycle thermal fatigue. Since 1998, EDF is making an inventory of all mixing areas in French PWR on basis of criteria. For all identified areas, a method was developed to improve the first classifying and to keep back only potential damage pipes. Presently, studies are performing on the charging line nozzle connected to the reactor pressure vessel. In order to evaluate the load history, a mock-up has been developed and mechanical calculations are realised on this nozzle. The paper will make an overview of EDF conclusions on these different points: - dead legs and vortex in a no flow connected line; - stratification; - mixing tees with high {delta}T. (authors)

  1. Innovation on high-power long-pulse gyrotrons

    NASA Astrophysics Data System (ADS)

    Litvak, Alexander; Sakamoto, Keishi; Thumm, Manfred

    2011-12-01

    Progress in the worldwide development of high-power gyrotrons for magnetic confinement fusion plasma applications is described. After technology breakthroughs in research on gyrotron components in the 1990s, significant progress has been achieved in the last decade, in particular, in the field of long-pulse and continuous wave (CW) gyrotrons for a wide range of frequencies. At present, the development of 1 MW-class CW gyrotrons has been very successful; these are applicable for self-ignition experiments on fusion plasmas and their confinement in the tokamak ITER, for long-pulse confinement experiments in the stellarator Wendelstein 7-X (W7-X) and for EC H&CD in the future tokamak JT-60SA. For this progress in the field of high-power long-pulse gyrotrons, innovations such as the realization of high-efficiency stable oscillation in very high order cavity modes, the use of single-stage depressed collectors for energy recovery, highly efficient internal quasi-optical mode converters and synthetic diamond windows have essentially contributed. The total tube efficiencies are around 50% and the purity of the fundamental Gaussian output mode is 97% and higher. In addition, activities for advanced gyrotrons, e.g. a 2 MW gyrotron using a coaxial cavity, multi-frequency 1 MW gyrotrons and power modulation technology, have made progress.

  2. High Temperature Aerogels for Thermal Protection Systems

    NASA Technical Reports Server (NTRS)

    Hurwitz, Frances I.; Mbah, Godfrey C.

    2008-01-01

    High temperature aerogels in the Al2O3-SiO2 system are being investigated as possible constituents for lightweight integrated thermal protection system (TPS) designs for use in supersonic and hypersonic applications. Gels are synthesized from ethoxysilanes and AlCl3.6H2O, using an epoxide catalyst. The influence of Al:Si ratio, solvent, water to metal and water to alcohol ratios on aerogel composition, morphology, surface area, and pore size distribution were examined, and phase transformation on heat treatment characterized. Aerogels have been fabricated which maintain porous, fractal structures after brief exposures to 1000 C. Incorporation of nanofibers, infiltration of aerogels into SiC foams, use of polymers for crosslinking the aerogels, or combinations of these, offer potential for toughening and integration of TPS with composite structure. Woven fabric composites having Al2O3-SiO2 aerogels as a matrix also have been fabricated. Continuing work is focused on reduction in shrinkage and optimization of thermal and physical properties.

  3. Deployment of an innovative thermally enhanced soil mixing process augmented with zero-valent iron.

    SciTech Connect

    Lynch, P. L.

    1999-01-15

    An innovative in-situ soil treatment process, referred to as soil mixing/thermally enhanced soil vapor extraction (SM/TESVE), was used to remediate the 317 Area of Argonne National Laboratory-East (i.e., Argonne), which is contaminated with volatile organic compounds (VOCs). Following the initial soil treatment, polishing was required to reduce residual concentrations of contaminants. A study of polishing methods was conducted. It determined that injecting metallic iron particles into the soil, in conjunction with soil mixing, would reduce residual VOC concentrations more effectively than the original conventional soil ventilation approach. After the effectiveness of iron injection was verified, it replaced the soil ventilation step. The modified process involved mixing the soil while hot air and steam were injected into it. Off-gases were captured in a hood over the treatment area. During this process, an iron slurry, consisting of up to 50% iron particles in water with guar gum added as a thickening agent, was injected and mixed into the soil by the mixing equipment. Approximately 6,246 m{sup 3} (8, 170 yd{sup 3}) of soil was treated during this project. Confirmatory samples were then collected. In these samples, VOC concentrations were usually reduced by more than 80%.

  4. Adventures in supercomputing: An innovative program for high school teachers

    SciTech Connect

    Oliver, C.E.; Hicks, H.R.; Summers, B.G.; Staten, D.G.

    1994-12-31

    Within the realm of education, seldom does an innovative program become available with the potential to change an educator`s teaching methodology. Adventures in Supercomputing (AiS), sponsored by the U.S. Department of Energy (DOE), is such a program. It is a program for high school teachers that changes the teacher paradigm from a teacher-directed approach of teaching to a student-centered approach. {open_quotes}A student-centered classroom offers better opportunities for development of internal motivation, planning skills, goal setting and perseverance than does the traditional teacher-directed mode{close_quotes}. Not only is the process of teaching changed, but the cross-curricula integration within the AiS materials is remarkable. Written from a teacher`s perspective, this paper will describe the AiS program and its effects on teachers and students, primarily at Wartburg Central High School, in Wartburg, Tennessee. The AiS program in Tennessee is sponsored by Oak Ridge National Laboratory (ORNL).

  5. Cancer therapy using non-thermal atmospheric pressure plasma with ultra-high electron density

    NASA Astrophysics Data System (ADS)

    Tanaka, Hiromasa; Mizuno, Masaaki; Toyokuni, Shinya; Maruyama, Shoichi; Kodera, Yasuhiro; Terasaki, Hiroko; Adachi, Tetsuo; Kato, Masashi; Kikkawa, Fumitaka; Hori, Masaru

    2015-12-01

    Cancer therapy using non-thermal atmospheric pressure plasma is a big challenge in plasma medicine. Reactive species generated from plasma are key factors for treating cancer cells, and thus, non-thermal atmospheric pressure plasma with high electron density has been developed and applied for cancer treatment. Various cancer cell lines have been treated with plasma, and non-thermal atmospheric plasma clearly has anti-tumor effects. Recent innovative studies suggest that plasma can both directly and indirectly affect cells and tissues, and this observation has widened the range of applications. Thus, cancer therapy using non-thermal atmospheric pressure plasma is promising. Animal experiments and understanding the mode of action are essential for clinical application in the future. A new academic field that combines plasma science, the biology of free radicals, and systems biology will be established.

  6. Cancer therapy using non-thermal atmospheric pressure plasma with ultra-high electron density

    SciTech Connect

    Tanaka, Hiromasa; Mizuno, Masaaki; Toyokuni, Shinya; Maruyama, Shoichi; Kodera, Yasuhiro; Terasaki, Hiroko; Adachi, Tetsuo; Kato, Masashi; Kikkawa, Fumitaka; Hori, Masaru

    2015-12-15

    Cancer therapy using non-thermal atmospheric pressure plasma is a big challenge in plasma medicine. Reactive species generated from plasma are key factors for treating cancer cells, and thus, non-thermal atmospheric pressure plasma with high electron density has been developed and applied for cancer treatment. Various cancer cell lines have been treated with plasma, and non-thermal atmospheric plasma clearly has anti-tumor effects. Recent innovative studies suggest that plasma can both directly and indirectly affect cells and tissues, and this observation has widened the range of applications. Thus, cancer therapy using non-thermal atmospheric pressure plasma is promising. Animal experiments and understanding the mode of action are essential for clinical application in the future. A new academic field that combines plasma science, the biology of free radicals, and systems biology will be established.

  7. Ultra low thermal expansion, highly thermal shock resistant ceramic

    DOEpatents

    Limaye, Santosh Y.

    1996-01-01

    Three families of ceramic compositions having the given formula: .phi..sub.1+X Zr.sub.4 P.sub.6-2X Si.sub.2X O.sub.24, .phi..sub.1+X Zr.sub.4-2X Y.sub.2X P.sub.6 O.sub.24 and .phi..sub.1+X Zr.sub.4-X Y.sub.X P.sub.6-2X Si.sub.X O.sub.24 wherein .phi. is either Strontium or Barium and X has a value from about 0.2 to about 0.8 have been disclosed. Ceramics formed from these compositions exhibit very low, generally near neutral, thermal expansion over a wide range of elevated temperatures.

  8. Ultra low thermal expansion, highly thermal shock resistant ceramic

    DOEpatents

    Limaye, S.Y.

    1996-01-30

    Three families of ceramic compositions having the given formula: {phi}{sub 1+X}Zr{sub 4}P{sub 6{minus}2X}Si{sub 2X}O{sub 24}, {phi}{sub 1+X}Zr{sub 4{minus}2X}Y{sub 2X}P{sub 6}O{sub 24} and {phi}{sub 1+X}Zr{sub 4{minus}X}Y{sub X}P{sub 6{minus}2X}Si{sub X}O{sub 24} wherein {phi} is either strontium or barium and X has a value from about 0.2 to about 0.8 have been disclosed. Ceramics formed from these compositions exhibit very low, generally near neutral, thermal expansion over a wide range of elevated temperatures. 7 figs.

  9. High temperature dependence of thermal transport in graphene foam.

    PubMed

    Li, Man; Sun, Yi; Xiao, Huying; Hu, Xuejiao; Yue, Yanan

    2015-03-13

    In contrast to the decreased thermal property of carbon materials with temperature according to the Umklapp phonon scattering theory, highly porous free-standing graphene foam (GF) exhibits an abnormal characteristic that its thermal property increases with temperature above room temperature. In this work, the temperature dependence of thermal properties of free-standing GF is investigated by using the transient electro-thermal technique. Significant increase for thermal conductivity and thermal diffusivity from ∼0.3 to 1.5 W m(-1) K(-1) and ∼4 × 10(-5) to ∼2 × 10(-4) m(2) s(-1) respectively is observed with temperature from 310 K to 440 K for three GF samples. The quantitative analysis based on a physical model for porous media of Schuetz confirms that the thermal conductance across graphene contacts rather than the heat conductance inside graphene dominates thermal transport of our GFs. The thermal expansion effect at an elevated temperature makes the highly porous structure much tighter is responsible for the reduction in thermal contact resistance. Besides, the radiation heat exchange inside the pores of GFs improves the thermal transport at high temperatures. Since free-standing GF has great potential for being used as supercapacitor and battery electrode where the working temperature is always above room temperature, this finding is beneficial for thermal design of GF-based energy applications. PMID:25683178

  10. High conductance thermal interface concept for space applications

    NASA Technical Reports Server (NTRS)

    Poulin, Elizabeth C.; Horan, D. C.

    1991-01-01

    An interface concept has been developed which produces high conductance at a thermal/mechanical joint without resorting to high clamping forces or potentially contaminating fillers such as thermal grease. This paper discusses the characteristics of several variations of the high conductance interface concept and compares them to those of existing interface concepts proposed for several Space Station applications. The application of the high conductance concept to thermal joints such as internal coldplate interfaces and external equipment module to heat acquisition plate interfaces would reduce the weight and complexity and increase the efficiency of the Space Station Thermal Management System.

  11. Innovation, Innovation, Innovation

    ERIC Educational Resources Information Center

    Schuller, Tom

    2007-01-01

    Innovation, Universities and Skills. The new title of the department offers much food for thought. The title is indeed an intriguing and important one. Bringing the idea of innovation right to the fore is, to use an overworked term, challenging. Pinning down what innovation means is not at all easy. There are three different lines of argument. The…

  12. Resilient thermal barrier for high temperatures

    NASA Technical Reports Server (NTRS)

    Frye, J. A.

    1977-01-01

    Abrasion-resistant thermal barrier, consisting of two layers of woven fabric or braided sleeving with bulk insulation sandwiched between, shows excellent resilience even after compression at temperatures above 980C.

  13. Innovative nanostructures for highly sensitive vibrational biosensing (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Popp, Juergen; Mayerhöfer, Thomas; Cialla-May, Dana; Weber, Karina; Huebner, Uwe

    2016-03-01

    Employing vibrational spectroscopy (IR-absorption and Raman spectroscopy) allows for the labelfree detection of molecular specific fingerprints of inorganic, organic and biological substances. The sensitivity of vibrational spectroscopy can be improved by several orders of magnitude via the application of plasmonic active surfaces. Within this contribution we will discuss two such approaches, namely surface enhanced Raman spectroscopy (SERS) as well as surface enhanced IR absorption (SEIRA). It will be shown that SERS using metal colloids as SERS active substrate in combination with a microfluidic lab-on-a-chip (LOC) device enables high throughput and reproducible measurements with highest sensitivity and specificity. The application of such a LOC-SERS approach for therapeutic drug monitoring (e.g. quantitative detection of antibiotics in a urine matrix) will be presented. Furthermore, we will introduce innovative bottom-up strategies to prepare SERS-active nanostructures coated with a lipophilic sensor layer as one-time use SERS substrates for specific food analysis (e.g. quantitative detection of toxic food colorants). The second part of this contribution presents a slit array metamaterial perfect absorber for IR sensing applications consisting of a dielectric layer sandwiched between two metallic layers of which the upper layer is perforated with a periodic array of slits. Light-matter interaction is greatly amplified in the slits, where also the analyte is concentrated, as the surface of the substrate is covered by a thin silica layer. Thus, already small concentrations of analytes down to a monolayer can be detected by refractive index sensing and identified by their spectral fingerprints with a standard mid-infrared lab spectrometer.

  14. Thermal stress in high temperature cylindrical fasteners

    NASA Technical Reports Server (NTRS)

    Blosser, Max L.

    1988-01-01

    Uninsulated structures fabricated from carbon or silicon-based materials, which are allowed to become hot during flight, are attractive for the design of some components of hypersonic vehicles. They have the potential to reduce weight and increase vehicle efficiency. Because of manufacturing contraints, these structures will consist of parts which must be fastened together. The thermal expansion mismatch between conventional metal fasteners and carbon or silicon-based structural materials may make it difficult to design a structural joint which is tight over the operational temperature range without exceeding allowable stress limits. In this study, algebraic, closed-form solutions for calculating the thermal stresses resulting from radial thermal expansion mismatch around a cylindrical fastener are developed. These solutions permit a designer to quickly evaluate many combinations of materials for the fastener and the structure. Using the algebraic equations developed, material properties and joint geometry were varied to determine their effect on thermal stresses. Finite element analyses were used to verify that the closed-form solutions derived give the correct thermal stress distribution around a cylindrical fastener and to investigate the effect of some of the simplifying assumptions made in developing the closed-form solutions for thermal stresses.

  15. Thermal Cyclic Behavior of Thermal and Environmental Barrier Coatings Investigated Under High-Heat-Flux Conditions

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Lee, Kang N.; Miller, Robert A.

    2002-01-01

    Environmental barrier coatings (EBC's) have been developed to protect silicon-carbide- (SiC) based ceramic components in gas turbine engines from high-temperature environmental attack. With continuously increasing demands for significantly higher engine operating temperature, future EBC systems must be designed for both thermal and environmental protection of the engine components in combustion gases. In particular, the thermal barrier functions of EBC's become a necessity for reducing the engine-component thermal loads and chemical reaction rates, thus maintaining the required mechanical properties and durability of these components. Advances in the development of thermal and environmental barrier coatings (TBC's and EBC's, respectively) will directly impact the successful use of ceramic components in advanced engines. To develop high-performance coating systems, researchers must establish advanced test approaches. In this study, a laser high-heat-flux technique was employed to investigate the thermal cyclic behavior of TBC's and EBC's on SiC-reinforced SiC ceramic matrix composite substrates (SiC/SiC) under high thermal gradient and thermal cycling conditions. Because the laser heat flux test approach can monitor the coating's real-time thermal conductivity variations at high temperature, the coating thermal insulation performance, sintering, and delamination can all be obtained during thermal cycling tests. Plasma-sprayed yttria-stabilized zirconia (ZrO2-8 wt% Y2O3) thermal barrier and barium strontium aluminosilicate-based environmental barrier coatings (BSAS/BSAS+mullite/Si) on SiC/SiC ceramic matrix composites were investigated in this study. These coatings were laser tested in air under thermal gradients (the surface and interface temperatures were approximately 1482 and 1300 C, respectively). Some coating specimens were also subject to alternating furnace cycling (in a 90-percent water vapor environment at 1300 C) and laser thermal gradient cycling tests

  16. Thermal Regime of High-power Laser Diodes

    NASA Astrophysics Data System (ADS)

    Bezotosnyi, V. V.; Krokhin, O. N.; Oleshchenko, V. A.; Pevtsov, V. F.; Popov, Yu. M.; Cheshev, E. A.

    We discuss the design and application perspectives of different crystal, ceramic and composite-type submounts with thermo-compensating properties as well as submounts from materials with high thermal conductivity for overcoming thermal problem in high-power laser diodes (LD) and improving thermal management of other high-power optoelectronic and electronic semiconductor devices. Thermal fields in high-power laser diodes were calculated in 3 D thermal model at CW operation for some heatsink designs taking into account the experimental dependence of laser total efficiency against pumping current in order to extend the range of reliable operation up to thermal loads 20-30 W and corresponding output optical power up to 15-20 W for 100 μm stripe laser diodes.

  17. Putative extremely high rate of proteome innovation in lancelets might be explained by high rate of gene prediction errors

    PubMed Central

    Bányai, László; Patthy, László

    2016-01-01

    A recent analysis of the genomes of Chinese and Florida lancelets has concluded that the rate of creation of novel protein domain combinations is orders of magnitude greater in lancelets than in other metazoa and it was suggested that continuous activity of transposable elements in lancelets is responsible for this increased rate of protein innovation. Since morphologically Chinese and Florida lancelets are highly conserved, this finding would contradict the observation that high rates of protein innovation are usually associated with major evolutionary innovations. Here we show that the conclusion that the rate of proteome innovation is exceptionally high in lancelets may be unjustified: the differences observed in domain architectures of orthologous proteins of different amphioxus species probably reflect high rates of gene prediction errors rather than true innovation. PMID:27476717

  18. A New and Innovative Use of the Thermal Knife and Kevlar Cord Components in a Restraint and Release System

    NASA Technical Reports Server (NTRS)

    Stewart, Alphonso; Brodeur, Stephen J. (Technical Monitor)

    2001-01-01

    A Kevlar cord and two thermal knives are key components in the Soar Array Restraint and Release System (SARRS) on the Microwave Anisotropy Probe (MAP) spacecraft at NASA's Goddard Space Flight Center. The SARRS uses a 25-foot (7.62 m) length Kevlar cord that encircles the spacecraft and secures the solar panels in stowed configuration for launch. Once in orbit, one of two redundantly configured thermal knives severs the Kevlar cord and permits the panels to deploy. The purpose of this paper is to present the details of the design, development test results, and the various innovations that were created during the development of this novel use of the thermal knife and Kevlar cord.

  19. The Development of Innovative Chemistry Learning Material for Bilingual Senior High School Students in Indonesia

    ERIC Educational Resources Information Center

    Situmorang, Manihar; Sitorus, Marham; Hutabarat, Wesly; Situmorang, Zakarias

    2015-01-01

    The development of innovative chemistry learning material for bilingual Senior High School (SHS) students in Indonesia is explained. The study is aimed to obtain an innovative chemistry learning material based on national curriculum in Indonesia to be used as a learning media in the teaching and learning activities. The learning material is…

  20. Spaces of Innovation: Experiences from Two Small High-Tech Firms

    ERIC Educational Resources Information Center

    Heiskanen, Tuula; Heiskanen, Hannu

    2011-01-01

    Purpose: By comparing two small high-tech firms specialising in medical technology this article seeks to answer the following questions: What are the key characteristics of innovation processes in the case firms? How do the mutual relationships between mental, social and physical spaces explain the different pathways in the innovation processes in…

  1. High-Stakes & Assessment Innovation: A Negative Correlation? Research Report.

    ERIC Educational Resources Information Center

    Ananda, Sri; Rabinowitz, Stanley

    This paper makes the case that, as implemented so far, there has been an inverse correlation between innovation and accountability in statewide assessment systems. The higher the stakes attached to the assessment results, the more conservative the assessment methodology ultimately used. Case studies of two state assessment programs were carried…

  2. High Thermal Conductivity Aligned Polyethylene-Graphene Nanocomposites

    NASA Astrophysics Data System (ADS)

    Garg, Jivtesh; Saeidijavash, Mortaza

    We investigate enhancement of thermal conductivity in polyethylene-graphene nanocomposites. The effect of alignment of both the polymer chains and the dispersed graphene flakes on thermal conductivity enhancement will be reported. In this work nanocomposites are prepared through microextrusion of polyethylene pellets and graphene nanopowder. Alignment is achieved through mechanical stretching of the nanocomposites. Thermal conductivity is measured using both Angstrom method and Laser flash. Variables involved in the study are the draw ratio and the weight percentage of graphene nanopowder. Results will shed light on the role of alignment of graphene flakes on enhancing thermal transport and provide new avenues to achieve ultra-high thermal conductivity in polymeric materials.

  3. Flexible Fabrics with High Thermal Conductivity for Advanced Spacesuits

    NASA Technical Reports Server (NTRS)

    Trevino, Luis A.; Bue, Grant; Orndoff, Evelyne; Kesterson, Matt; Connel, John W.; Smith, Joseph G., Jr.; Southward, Robin E.; Working, Dennis; Watson, Kent A.; Delozier, Donovan M.

    2006-01-01

    This paper describes the effort and accomplishments for developing flexible fabrics with high thermal conductivity (FFHTC) for spacesuits to improve thermal performance, lower weight and reduce complexity. Commercial and additional space exploration applications that require substantial performance enhancements in removal and transport of heat away from equipment as well as from the human body can benefit from this technology. Improvements in thermal conductivity were achieved through the use of modified polymers containing thermally conductive additives. The objective of the FFHTC effort is to significantly improve the thermal conductivity of the liquid cooled ventilation garment by improving the thermal conductivity of the subcomponents (i.e., fabric and plastic tubes). This paper presents the initial system modeling studies, including a detailed liquid cooling garment model incorporated into the Wissler human thermal regulatory model, to quantify the necessary improvements in thermal conductivity and garment geometries needed to affect system performance. In addition, preliminary results of thermal conductivity improvements of the polymer components of the liquid cooled ventilation garment are presented. By improving thermal garment performance, major technology drivers will be addressed for lightweight, high thermal conductivity, flexible materials for spacesuits that are strategic technical challenges of the Exploration

  4. Innovative Airbreathing Propulsion Concepts for High-speed Applications

    NASA Technical Reports Server (NTRS)

    Whitlow, Woodrow, Jr.

    2002-01-01

    The current cost to launch payloads to low earth orbit (LEO) is approximately loo00 U.S. dollars ($) per pound ($22000 per kilogram). This high cost limits our ability to pursue space science and hinders the development of new markets and a productive space enterprise. This enterprise includes NASA's space launch needs and those of industry, universities, the military, and other U.S. government agencies. NASA's Advanced Space Transportation Program (ASTP) proposes a vision of the future where space travel is as routine as in today's commercial air transportation systems. Dramatically lower launch costs will be required to make this vision a reality. In order to provide more affordable access to space, NASA has established new goals in its Aeronautics and Space Transportation plan. These goals target a reduction in the cost of launching payloads to LEO to $lo00 per pound ($2200 per kilogram) by 2007 and to $100' per pound by 2025 while increasing safety by orders of magnitude. Several programs within NASA are addressing innovative propulsion systems that offer potential for reducing launch costs. Various air-breathing propulsion systems currently are being investigated under these programs. The NASA Aerospace Propulsion and Power Base Research and Technology Program supports long-term fundamental research and is managed at GLenn Research Center. Currently funded areas relevant to space transportation include hybrid hyperspeed propulsion (HHP) and pulse detonation engine (PDE) research. The HHP Program currently is addressing rocket-based combined cycle and turbine-based combined cycle systems. The PDE research program has the goal of demonstrating the feasibility of PDE-based hybrid-cycle and combined cycle propulsion systems that meet NASA's aviation and access-to-space goals. The ASTP also is part of the Base Research and Technology Program and is managed at the Marshall Space Flight Center. As technologies developed under the Aerospace Propulsion and Power Base

  5. Microbial Biosignatures in High Iron Thermal Springs

    NASA Astrophysics Data System (ADS)

    Parenteau, M. N.; Embaye, T.; Jahnke, L. L.; Cady, S. L.

    2003-12-01

    The emerging anoxic source waters at Chocolate Pots hot springs in Yellowstone National Park contain 2.6 to 11.2 mg/L Fe(II) and are 51-54° C and pH 5.5-6.0. These waters flow down the accumulating iron deposits and over three major phototrophic mat communities: Synechococcus/Chloroflexus at 51-54° C, Pseudanabaena at 51-54° C, and a narrow Oscillatoria at 36-45° C. We are assessing the contribution of the phototrophs to biosignature formation in this high iron system. These biosignatures can be used to assess the biological contribution to ancient iron deposits on Earth (e.g. Precambrian Banded Iron Formations) and, potentially, to those found on Mars. Most studies to date have focused on chemotrophic iron-oxidizing communities; however, recent research has demonstrated that phototrophs have a significant physiological impact on these iron thermal springs (Pierson et al. 1999, Pierson and Parenteau 2000, and Trouwborst et al., 2003). We completed a survey of the microfossils, biominerals, biofabrics, and lipid biomarkers in the phototrophic mats and stromatolitic iron deposits using scanning and transmission electron microscopy (SEM and TEM), energy dispersive spectrometry (EDS), powder X-ray diffraction (XRD), and gas chromatography-mass spectroscopy (GC-MS). The Synechococcus/Chloroflexus mat was heavily encrusted with iron silicates while the narrow Oscillatoria mat was encrusted primarily with iron oxides. Encrustation of the cells increased with depth in the mats. Amorphous 2-line ferrihydrite is the primary precipitate in the spring and the only iron oxide mineral associated with the mats. Goethite, hematite, and siderite were detected in dry sediment samples on the face of the main iron deposit. Analysis of polar lipid fatty acid methyl esters (FAME) generated a suite of lipid biomarkers. The Synechococcus/Chloroflexus mat contained two mono-unsaturated isomers of n-C18:1 with smaller amounts of polyunsaturated n-C18:2, characteristic of cyanobacteria

  6. The Origin of High Thermal Conductivity and Ultralow Thermal Expansion in Copper-Graphite Composites.

    PubMed

    Firkowska, Izabela; Boden, André; Boerner, Benji; Reich, Stephanie

    2015-07-01

    We developed a nanocomposite with highly aligned graphite platelets in a copper matrix. Spark plasma sintering ensured an excellent copper-graphite interface for transmitting heat and stress. The resulting composite has superior thermal conductivity (500 W m(-1) K(-1), 140% of copper), which is in excellent agreement with modeling based on the effective medium approximation. The thermal expansion perpendicular to the graphite platelets drops dramatically from ∼20 ppm K(-1) for graphite and copper separately to 2 ppm K(-1) for the combined structure. We show that this originates from the layered, highly anisotropic structure of graphite combined with residual stress under ambient conditions, that is, strain-engineering of the thermal expansion. Combining excellent thermal conductivity with ultralow thermal expansion results in ideal materials for heat sinks and other devices for thermal management. PMID:26083322

  7. Thermal barrier coating having high phase stability

    DOEpatents

    Subramanian, Ramesh

    2002-01-01

    A device (10) comprising a substrate (22) having a deposited ceramic thermal barrier coating characterized by a microstructure having gaps (28) where the thermal barrier coating comprises a first thermal barrier layer (40), and a second thermal barrier layer (30) with a pyrochlore crystal structure having a chemical formula of A.sup.n+.sub.2-x B.sup.m+.sub.2+x O.sub.7-y, where A is selected from the group of elements consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and mixtures thereof, where B is selected from the group of elements consisting of Zr, Hf, Ti and mixtures thereof, where n and m are the valence of A and B respectively, and for -0.5.ltoreq.x.ltoreq.0.5, ##EQU1## and excluding the following combinations for x=0, y=0: A=La and B=Zr; A=La and B=Hf; A=Gd and B=Hf; and A=Yb and B=Ti.

  8. Simple high-temperature thermal diffusivity apparatus

    NASA Technical Reports Server (NTRS)

    Wood, C.; Zoltan, A.

    1984-01-01

    A simple and inexpensive thermal diffusivity apparatus is described for measurement up to 1600 K. The novel features of apparatus include a light pipe, a long furnace, and a differential thermocouple. A low heat-load sample holder for clamping the sample in a vertical position is also described. The results of measurements on AXM-5Q graphite are reported.

  9. Thermal Shock Behavior of Single Crystal Oxide Refractive Concentrators for High Temperatures Solar Thermal Propulsion

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Choi, Sung R.; Jacobson, Nathan S.; Miller, Robert A.

    1999-01-01

    Single crystal oxides such as yttria-stabilized zirconia (Y2O3-ZrO2), yttrium-aluminum-garnet (Y3Al5O12, or YAG), magnesium oxide (MgO) and sapphire (Al2O3) have been considered as refractive secondary concentrator materials for high temperature solar propulsion applications. However, thermal mechanical reliability of the oxide components in severe thermal environments during space mission sun/shade transitions is of great concern. In this paper, critical mechanical properties of these oxide crystals are determined by the indentation technique. Thermal shock resistance of the oxides is evaluated using a high power CO, laser under high temperature-high thermal gradients. Thermal stress fracture behavior and failure mechanisms of these oxide materials are investigated under various temperature and heating conditions.

  10. High speed heterodyne infrared thermography applied to thermal diffusivity identification

    NASA Astrophysics Data System (ADS)

    Pradere, C.; Clerjaud, L.; Batsale, J. C.; Dilhaire, S.

    2011-05-01

    We have combined InfraRed thermography and thermal wave techniques to perform microscale, ultrafast (microsecond) temperature field measurements. The method is based on an IR camera coupled to a microscope and synchronized to the heat source by means of phase locked function generators. The principle is based on electronic stroboscopic sampling where the low IR camera acquisition frequency facq (25 Hz) undersamples a high frequency thermal wave. This technique permits the measurement of the emissive thermal response at a (microsecond) short time scale (microsecond) with the full frame mode of the IR camera with a spatial thermal resolution of 7 μm. Then it becomes possible to study 3D transient heat transfer in heterogeneous and high thermal conductive thin layers. Thus it is possible for the first time in our knowledge to achieve temperature field measurements in heterogeneous media within a wide range of time domains. The IR camera is now a suitable instrument for multiscale thermal analysis.

  11. Development of Mitsubishi High Thermal Performance Grid

    NASA Astrophysics Data System (ADS)

    Ikeda, Kazuo; Hoshi, Masaya

    Mitsubishi has developed a new zircalloy grid spacer for PWR fuel with higher thermal performance. Computational Fluid Dynamics (CFD) evaluation method has been applied for designing of the new lower pressure loss and higher Departure from Nucleate Boiling (DNB) benefit grid spacer. Reduction of pressure loss of grid structures has been examined by CFD. Also, CFD has been developed as a design tool to predict the coolant mixing ability of vane structures, which is to compare the relative peak spot temperatures around fuel rods at the same heat flux condition. Prototype grids were manufactured and several tests, which were pressure loss measurements, cross-flow measurements and freon DNB tests, were conducted to verify CFD predictions. It is concluded that the applicability of the CFD evaluation method for the thermal hydraulic design of the grid is confirmed.

  12. [The venture financing of scientifically-innovative projects: teaching experience in medical high school].

    PubMed

    Grachev, S V; Gorodnova, E A

    2008-01-01

    The authors presented an original material, devoted to first experience of teaching of theoretical bases of venture financing of scientifically-innovative projects in medical high school. The results and conclusions were based on data of the questionnaire performed by the authors. More than 90% of young scientist physicians recognized actuality of this problem for realization of their research work results into practice. Thus, experience of teaching of theoretical bases of venture financing of scientifically-innovative projects in medical high school proves reasonability of further development and inclusion the module "The venture financing of scientifically-innovative projects in biomedicine" in the training plan. PMID:18589734

  13. An Innovative Approach To Teaching High School Students about Indoor Air Quality.

    ERIC Educational Resources Information Center

    Neumann, Catherine M.; Bloomfield, Molly M.; Harding, Anna K.; Sherburne, Holly

    1999-01-01

    Describes an innovative approach used to help high school students develop critical thinking and real-world problem-solving skills while learning about indoor air quality. (Contains 13 references.) (Author/WRM)

  14. Factor Pattern Comparisons of EPPS Scales of High School, College, and Innovative College Program Students

    ERIC Educational Resources Information Center

    Dixon, Paul W.; Ahern, Elsie H.

    1973-01-01

    EPPS scores from 167 high school seniors (Study 1, S1), 137 introductory psychology students (S2), and students from an innovative college program (S3) were compared using analysis of variance, image analysis, and factor pattern comparison. (Editor)

  15. HIGH VOLTAGE ENVIRONMENTAL APPLICATIONS, INC.ELECTRON BEAM TECHNOLOGY - INNOVATIVE TECHNOLOGY EVALUATION REPORT

    EPA Science Inventory

    This report evaluates a high-voltage electron beam (E-beam) technology's ability to destroy volatile organic compounds (VOCs) and other contaminants present in liquid wastes. Specifically, this report discusses performance and economic data from a Superfund Innovative Technology...

  16. WSN system design by using an innovative neural network model to perform thermals forecasting in a urban canyon scenario

    NASA Astrophysics Data System (ADS)

    Giuseppina, Nicolosi; Salvatore, Tirrito

    2015-12-01

    Wireless Sensor Networks (WSNs) were studied by researchers in order to manage Heating, Ventilating and Air-Conditioning (HVAC) indoor systems. WSN can be useful specially to regulate indoor confort in a urban canyon scenario, where the thermal parameters vary rapidly, influenced by outdoor climate changing. This paper shows an innovative neural network approach, by using WSN data collected, in order to forecast the indoor temperature to varying the outdoor conditions based on climate parameters and boundary conditions typically of urban canyon. In this work more attention will be done to influence of traffic jam and number of vehicles in queue.

  17. Design and modelling of an innovative three-stage thermal storage system for direct steam generation CSP plants

    NASA Astrophysics Data System (ADS)

    Garcia, Pierre; Vuillerme, Valéry; Olcese, Marco; El Mourchid, Nadim

    2016-05-01

    Thermal Energy Storage systems (TES) for a Direct Steam Generation (DSG) solar plant feature preferably three stages in series including a latent heat storage module so that steam can be recovered with a limited temperature loss. The storage system designed within the Alsolen Sup project is characterized by an innovative combination of sensible and latent modules. A dynamic model of this three-stage storage has been developed and applied to size the storage system of the Alsolen Sup® plant demonstrator at CEA Cadarache. Results of this simulation show that this promising concept is an efficient way to store heat in DSG solar plants.

  18. Thermal distribution in high power optical devices with power-law thermal conductivity

    NASA Astrophysics Data System (ADS)

    Zhou, Chuanle; Grayson, M.

    2012-01-01

    We introduce a power-law approximation to model non-linear ranges of the thermal conductivity, and under this approximation derive a simple analytical expression for calculating the temperature profile in high power quantum cascade lasers and light emitting diodes. The thermal conductivity of a type II InAs/GaSb superlattice (T2SL) is used as an example, having negative or positive power-law exponents depending on the thermal range of interest. The result is an increase or decrease in the temperature, respectively, relative to the uniform thermal conductivity assumption.

  19. High Growth Rate YSZ Thermal Barrier Coatings Deposited by MOCVD Demonstrate High Thermal Cycling Lifetime

    SciTech Connect

    Varanasi, Venu G; Besmann, Theodore M; Payzant, E Andrew; Pint, Bruce A; Lothian, Janet L; Anderson, Timothy J

    2011-01-01

    Yttria-stabilized zirconia (YSZ) thermal barrier coatings (TBC) were prepared by metalorganic chemical vapor deposition (MOCVD) using Y(OBut{sup n}){sub 3}, Zr(OBut{sup n}){sub 4} precursors and O{sub 2} carrier gas. A thermodynamic analysis guided experiments by optimizing elemental molar (n) stoichiometric ratios for the (Zr-Y-O-C-H system). This analysis showed single-phase YSZ was favored at 950 C, 1 kPa, n{sub O}/(n{sub Y} + n{sub Zr}) > 30, n{sub Y}/(n{sub Y} + n{sub Zr}) = 0.06-0.10 (fixed n{sub C}, n{sub H}). Experimental YSZ growth had multiple phases (fcc, monoclinic), had a relatively high growth rate (43 {micro}m/h, 1005 C), had an Arrhenius dependence (845-950 C, E{sub a} = 53.8 {+-} 7.9 kJ/mol), had columnar grains (SEM analysis), and had a coating through-thickness n{sub Y}/(n{sub Y} + n{sub Zr}) = 0.04 (EPMA analysis). Doubling the inlet yttrium precursor mole fraction resulted in fcc YSZ growth with a coating through-thickness n{sub Y}/(n{sub Y} + n{sub Zr}) = 0.07. Hot-insertion thermal cycling of YSZ coatings on FeCrAlY bond coats showed >1000 h lifetime, matching current standards for EB-PVD YSZ coatings.

  20. High performance thermal imaging for the 21st century

    NASA Astrophysics Data System (ADS)

    Clarke, David J.; Knowles, Peter

    2003-01-01

    In recent years IR detector technology has developed from early short linear arrays. Such devices require high performance signal processing electronics to meet today's thermal imaging requirements for military and para-military applications. This paper describes BAE SYSTEMS Avionics Group's Sensor Integrated Modular Architecture thermal imager which has been developed alongside the group's Eagle 640×512 arrays to provide high performance imaging capability. The electronics architecture also supprots High Definition TV format 2D arrays for future growth capability.

  1. Long life high reliability thermal control systems study data handbook

    NASA Technical Reports Server (NTRS)

    Scollon, T. R., Jr.; Carpitella, M. J.

    1971-01-01

    The development of thermal control systems with high reliability and long service life is discussed. Various passive and semi-active thermal control systems which have been installed on space vehicles are described. The properties of the various coatings are presented in tabular form.

  2. Measuring Thermal Diffusivity Of A High-Tc Superconductor

    NASA Technical Reports Server (NTRS)

    Powers, Charles E.; Oh, Gloria; Leidecker, Henning

    1992-01-01

    Technique for measuring thermal diffusivity of superconductor of high critical temperature based on Angstrom's temperature-wave method. Peltier junction generates temperature oscillations, which propagate with attenuation up specimen. Thermal diffusivity of specimen calculated from distance between thermocouples and amplitudes and phases of oscillatory components of thermocouple readings.

  3. High-Resolution Thermal Inertia Mapping from the Mars Global Surveyor Thermal Emission Spectrometer

    USGS Publications Warehouse

    Mellon, M.T.; Jakosky, B.M.; Kieffer, H.H.; Christensen, P.R.

    2000-01-01

    High-resolution thermal inertia mapping results are presented, derived from Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES) observations of the surface temperature of Mars obtained during the early portion of the MGS mapping mission. Thermal inertia is the key property controlling the diurnal surface temperature variations, and is dependent on the physical character of the top few centimeters of the surface. It represents a complex combination of particle size, rock abundance, exposures of bedrock, and degree of induration. In this work we describe the derivation of thermal inertia from TES data, present global scale analysis, and place these results into context with earlier work. A global map of nighttime thermal-bolometer-based thermal inertia is presented at 14?? per pixel resolution, with approximately 63% coverage between 50??S and 70??N latitude. Global analysis shows a similar pattern of high and low thermal inertia as seen in previous Viking low-resolution mapping. Significantly more detail is present in the high-resolution TES thermal inertia. This detail represents horizontal small-scale variability in the nature of the surface. Correlation with albedo indicates the presence of a previously undiscovered surface unit of moderate-to-high thermal inertia and intermediate albedo. This new unit has a modal peak thermal inertia of 180-250 J m-2 K-1 s-12 and a narrow range of albedo near 0.24. The unit, covering a significant fraction of the surface, typically surrounds the low thermal inertia regions and may comprise a deposit of indurated fine material. Local 3-km-resolution maps are also presented as examples of eolian, fluvial, and volcanic geology. Some impact crater rims and intracrater dunes show higher thermal inertias than the surrounding terrain; thermal inertia of aeolian deposits such as intracrater dunes may be related to average particle size. Outflow channels and valleys consistently show higher thermal inertias than the

  4. Kapitza thermal resistance studied by high-frequency photothermal radiometry

    NASA Astrophysics Data System (ADS)

    Horny, Nicolas; Chirtoc, Mihai; Fleming, Austin; Hamaoui, Georges; Ban, Heng

    2016-07-01

    Kapitza thermal resistance is determined using high-frequency photothermal radiometry (PTR) extended for modulation up to 10 MHz. Interfaces between 50 nm thick titanium coatings and silicon or stainless steel substrates are studied. In the used configuration, the PTR signal is not sensitive to the thermal conductivity of the film nor to its optical absorption coefficient, thus the Kapitza resistance is directly determined from single thermal parameter fits. Results of thermal resistances show the significant influence of the nature of the substrate, as well as of the presence of free electrons at the interface.

  5. Thermal barrier coating having high phase stability

    DOEpatents

    Subramanian, Ramesh

    2001-01-01

    A device (10) comprising a substrate (22) having a deposited ceramic thermal barrier coating layer (20) characterized by a microstructure having gaps (28) where the thermal barrier coating (20) consists essentially of a pyrochlore crystal structure having a chemical formula consisting essentially of A.sup.n+.sub.2-x B.sup.m+.sub.2+x O.sub.7-y, where A is selected from the group of elements selected from La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and mixtures thereof; where B is selected from the group of elements selected from Zr, Hf, Ti and mixtures thereof; n and m are the valence of A and B respectively, and for -0.5.ltoreq.x.ltoreq.0.5, ##EQU1## and excluding the following combinations for x=0, y=0: A=La and B=Zr; A=La and B=Hf; A=Gd and B=Hf; and A=Yb and B=Ti.

  6. Investigation of Thermal High Cycle and Low Cycle Fatigue Mechanisms of Thick Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dong-Ming; Miller, Robert A.

    1998-01-01

    Ceramic thermal barrier coatings have attracted increased attention for diesel engine applications. The advantages of using the ceramic coatings include a potential increase in efficiency and power density and a decrease in maintenance cost. Zirconia-based ceramics are the most important coating materials for such applications because of their low thermal conductivity, relatively high thermal expansivity and excellent mechanical properties. However, durability of thick thermal barrier coatings (TBCS) under severe temperature cycling encountered in engine conditions, remains a major question. The thermal transients associated with the start/stop and no-load/full-load engine cycle, and with the in-cylinder combustion process, generate thermal low cycle fatigue (LCF) and thermal high cycle fatigue (HCF) in the coating system. Therefore, the failure mechanisms of thick TBCs are expected to be quite different from those of thin TBCs under these temperature transients. The coating failure is related not only to thermal expansion mismatch and oxidation of the bond coats and substrates, but also to the steep thermal stress gradients induced in the coating systems. Although it has been reported that stresses generated by thermal transients can initiate surface and interface cracks in a coating system, the mechanisms of the crack propagation and of coating failure under the complex LCF and HCF conditions are still not understood. In this paper, the thermal fatigue behavior of an yttria partially stabilized zirconia coating system under simulated LCF and HCF engine conditions is investigated. The effects of LCF and HCF on surface crack initiation and propagation are also discussed.

  7. High thermal conductivity lossy dielectric using a multi layer configuration

    DOEpatents

    Tiegs, Terry N.; Kiggans, Jr., James O.

    2003-01-01

    Systems and methods are described for loss dielectrics. A loss dielectric includes at least one high dielectric loss layer and at least one high thermal conductivity-electrically insulating layer adjacent the at least one high dielectric loss layer. A method of manufacturing a loss dielectric includes providing at least one high dielectric loss layer and providing at least one high thermal conductivity-electrically insulating layer adjacent the at least one high dielectric loss layer. The systems and methods provide advantages because the loss dielectrics are less costly and more environmentally friendly than the available alternatives.

  8. Highly anisotropic thermal conductivity of arsenene: An ab initio study

    NASA Astrophysics Data System (ADS)

    Zeraati, Majid; Vaez Allaei, S. Mehdi; Abdolhosseini Sarsari, I.; Pourfath, Mahdi; Donadio, Davide

    2016-02-01

    Elemental two-dimensional (2D) materials exhibit intriguing heat transport and phononic properties. Here we have investigated the lattice thermal conductivity of newly proposed arsenene, the 2D honeycomb structure of arsenic, using ab initio calculations. Solving the Boltzmann transport equation for phonons, we predict a highly anisotropic thermal conductivity of 30.4 and 7.8 W/mK along the zigzag and armchair directions, respectively, at room temperature. Our calculations reveal that phonons with mean free paths between 20 nm and 1 μ m provide the main contribution to the large thermal conductivity in the zigzag direction; mean free paths of phonons contributing to heat transport in the armchair directions range between 20 and 100 nm. The obtained anisotropic thermal conductivity and feasibility of synthesis, in addition to high electron mobility reported elsewhere, make arsenene a promising material for nanoelectronic applications and thermal management.

  9. Ultralow thermal conductivity in highly anion-defective aluminates.

    PubMed

    Wan, Chunlei; Qu, Zhixue; He, Yong; Luan, Dong; Pan, Wei

    2008-08-22

    Ultralow thermal conductivity (1.1 W/m.K, 1000 degrees C) in anion-deficient Ba2RAlO5 (R=Dy, Er, Yb) compounds was reported. The low thermal conductivity was then analyzed by kinetic theory. The highly defective structure of Ba2RAlO5 results in weak atomic bond strength and low sound speeds, and phonon scattering by large concentration of oxygen vacancies reduces the phonon mean free path to the order of interatomic distance. Ba2DyAlO5 exhibits the shortest phonon mean free path and lowest thermal conductivity among the three compositions investigated, which can be attributed to additional phonon scattering by DyO6 octahedron tilting as a result of a low tolerance factor. The Ba2RAlO5 (R=Dy, Er, Yb) compounds have shown great potential in high-temperature thermal insulation applications, particularly as a thermal barrier coating material. PMID:18764638

  10. High reflector absorptance measurements by the surface thermal lensing technique

    SciTech Connect

    Chow, R.; Taylor, J.R.; Wu, Z.L.; Krupka, R.; Yang, T.

    1996-11-01

    Surface thermal lensing is an alternate configuration of a photothermal deflection system that was used to measure low levels of optical absorption. The thermal lensing configuration facilitated the alignment of the pump and probe laser beams by using a larger diameter probe beam. This technique was applied to high performance optical coatings, specifically high reflectors at 511 nm, zero degrees angle of incidence. The absorptance of these coatings was previously measured using a high power copper vapor laser system. A high power copper laser beam is focused onto a -2 mm diameter spot. A thermal camera senses the temperature rise with respect to the rest of the coating. The temperature change, power density and beam diameter were used with an empirical formula that yields optical absorption. The surface thermal lensing technique was able to resolve absorption levels lower than that achieved with the copper laser method.

  11. High Density Thermal Energy Storage with Supercritical Fluids

    NASA Technical Reports Server (NTRS)

    Ganapathi, Gani B.; Wirz, Richard

    2012-01-01

    A novel approach to storing thermal energy with supercritical fluids is being investigated, which if successful, promises to transform the way thermal energy is captured and utilized. The use of supercritical fluids allows cost-affordable high-density storage with a combination of latent heat and sensible heat in the two-phase as well as the supercritical state. This technology will enhance penetration of several thermal power generation applications and high temperature water for commercial use if the overall cost of the technology can be demonstrated to be lower than the current state-of-the-art molten salt using sodium nitrate and potassium nitrate eutectic mixtures.

  12. A high temperature molten salt thermal electrochemical cell

    NASA Astrophysics Data System (ADS)

    Plichta, Edward J.; Behl, Wishvender K.

    1990-02-01

    This invention relates in general to a high temperature molten salt thermal electrochemical cell and in particular to such a cell including cobalt oxide (Co3O4) as the cathode material. High temperature molten salt thermal electrochemical cells are widely used as power sources for projectiles, rockets, bombs, mines, missiles, decoys, jammers, and torpedoes. These are also used as fuses. Thermal electrochemical cells are reserve-type cells that can be activated by heating with a pyrotechnic heat source such as zirconium and barium chromate powders or mixtures of iron powder and potassium perchlorate.

  13. Thermal High- and Low-Cycle Fatigue Behavior of Thick Thermal Barrier Coating Systems

    NASA Technical Reports Server (NTRS)

    Miller, Robert A.

    1998-01-01

    Ceramic thermal barrier coatings have received increasing attention for advanced gas turbine and diesel engine applications because of their ability to provide thermal insulation to engine components. However, the durability of these coatings under the severe thermal cycling conditions encountered in a diesel engine (ref. 1) still remains a major issue. In this research at the NASA Lewis Research Center, a high-power laser was used to investigate the thermal fatigue behavior of a yttria-stabilized zirconia coating system under simulated diesel engine conditions. The mechanisms of fatigue crack initiation and propagation, and of coating failure under complex thermal low-cycle fatigue (LCF, representing stop/start cycles) and thermal high-cycle fatigue (HCF, representing operation at 1300 rpm) are described. Continuous wave and pulse laser modes were used to simulate pure LCF and combined LCF/HCF, respectively (ref. 2). The LCF mechanism was found to be closely related to the coating sintering and creep at high temperatures. These creep strains in the ceramic coating led to a tensile stress state during cooling, thus providing the major driving force for crack growth under LCF conditions. The combined LCF/HCF tests induced more severe coating surface cracking, microspallation, and accelerated crack growth than did the pure LCF test. HCF thermal loads also facilitated lateral crack branching and ceramic/bond coat interface delaminations. HCF is associated with the cyclic stresses originating from the high-frequency temperature fluctuation at the ceramic coating surface. The HCF thermal loads act on the crack by a wedging mechanism (ref. 1), resulting in continuous crack growth at temperature. The HCF stress intensity factor amplitude increases with the interaction depth and temperature swing, and decreases with the crack depth. HCF damage also increases with the thermal expansion coefficient and the Young's modulus of the ceramic coating (refs. 1 and 3).

  14. Applications of high thermal conductivity composites to electronics and spacecraft thermal design

    NASA Technical Reports Server (NTRS)

    Sharp, G. Richard; Loftin, Timothy A.

    1990-01-01

    Recently, high thermal conductivity graphite fiber-reinforced metal matrix composites (MMCs) have become available that can save weight over present methods of heat conduction. Another significant advantage is that these materials can be used without the plumbing and testing complexities that accompany the use of liquid heat pipes. A spinoff of this research was the development of other MMCs as electronic device heat sinks. These use particulates rather than fibers and are formulated to match the coefficient of thermal expansion of electronic substrates in order to alleviate thermally induced stresses. The development of both types of these materials as viable weight-saving substitutes for the traditional methods of thermal control for electronics packaging and also for spacecraft thermal control applications are the subjects of this report.

  15. Innovations in high-pressure liquid injection technique for gas chromatography: pressurized liquid injection system.

    PubMed

    Luong, Jim; Gras, Ronda; Tymko, Richard

    2003-01-01

    In gas chromatography (GC), highly volatile liquefied hydrocarbons are commonly injected using devices such as high-pressure syringes, piston valves, liquid rotary sampling valves, or vaporizing regulators. Although these techniques are adequate in some cases, there are known deficiencies. A new generation of sampling valve has been recently innovated and commercialized. Some of the highlights of the pressurized liquid injection system (PLIS) include compact size, the capability to directly couple to an injection port without the need for preinjection vaporization and transfer lines, and sample sizes ranging from 0.2 to 2.0 micro L. Although the valve has a specification of helium leak-free rating of 82.7 bar (1200 psig), the valve passes a hydrostatic pressure test of up to 414 bar (6000 psig). In the unheated version of PLIS, vaporization of solutes occur mainly because of the sheering effect of carrier gas in combination with thermal energy drawn from an injection port or a heated adaptor. This was found to be adequate for solutes with high to medium volatility of up to nC14 hydrocarbon. A higher molecular weight range of up to nC44 hydrocarbon can be achieved with the implementation of a heated version of PLIS, in which the channel of the shaft can be resistively heated at a rate of up to 400 degrees C/s. With its first introduction in May 2002, PLIS has gained acceptance amongst practitioners in GC because it addresses a key unarticulated need in sample introduction/enrichment and by specifically targeting many deficiencies encountered in contemporary high-pressure injection devices. In this paper, the design and performance of the various valve systems of PLIS, as well as industrial chromatographic applications, is presented. PMID:14629794

  16. Fibers innovative burning and reuse by Self-propagating High temperature Synthesis (SHS)

    NASA Astrophysics Data System (ADS)

    Caratto, Valentina; Belfortini, Claudio; Musi, Luigi; Gaggero, Laura; Ferretti, Maurizio

    2016-04-01

    The treatment of asbestos containing waste deriving from civil building and industrial applications is a social alert and an environmental problem. The project LIFE12 ENV/IT 000295 FIBERS "Fibers innovative burning and reuse by Self-propagating High temperature Synthesis (SHS)" has developed an innovative technique alternative to conventional high T processes. The University of Genoa has developed an apparatus and a technique for triggering the breakdown reaction of chrysotile by means of an alumino-thermic reaction in a process of combustion synthesis well known as Self-propagating High temperature Synthesis or SHS. This approach yielded interesting results and allowed the development of an efficient method for inerting natural asbestos fibers and man-made products carrying fibers at the scale of some grams [1]. The experiments were based on the couples Fe2O3/Mg by implementation of two prototype plants. The varying parameters were: 1) different Asbestos-Containing Waste (ACW) massive (Eternit, linoleum) and friable asbestos; 2) ACW abundance; 3) size of the pellet 4) under two triggering systems (induction by a W coil and oxyacetylene torch). The reactions were carried in two configurations: a) discontinuous, allowed us to obtain data for the development and fine-tuning of the reaction, b) continuous, was indispensable for the development and fine-tuning of the process parameters towards industrial scale up. After the combustive reaction all samples were characterized by SEM-EDS and XRPD analysis. All experiments demonstrated effective in destructing the fibrous habit of chrysotile, turning its composition to stubby olivine grains. We optimized the parameters to achieve complete conversion of the asbestos to mineral grains in all the cases. The efficiency of the SHS reaction in the discontinuous and continuous configurations was highlighted by the characterization of the post-combustion material under SEM-EDS and XRPD that verified the absence of fibers within

  17. Experimental measurements of thermal properties of high-temperature refractory materials used for thermal energy storage

    NASA Astrophysics Data System (ADS)

    El-Leathy, Abdelrahman; Jeter, Sheldon; Al-Ansary, Hany; Abdel-Khalik, Said; Golob, Matthew; Danish, Syed Noman; Saeed, Rageh; Djajadiwinata, Eldwin; Al-Suhaibani, Zeyad

    2016-05-01

    This paper builds on studies conducted on thermal energy storage (TES) systems that were built as a part of the work performed for a DOE-funded SunShot project titled "High Temperature Falling Particle Receiver". In previous studies, two small-scale TES systems were constructed for measuring heat loss at high temperatures that are compatible with the falling particle receiver concept, both of which had shown very limited heat loss. Through the course of those studies, it became evident that there was a lack of information about the thermal performance of some of the insulating refractory materials used in the experiments at high temperatures, especially insulating firebrick and perlite concrete. This work focuses on determining the thermal conductivities of those materials at high temperatures. The apparatus consists of a prototype cylindrical TES bin built with the same wall construction used in previous studies. An electric heater is placed along the centerline of the bin, and thermocouples are used to measure temperature at the interfaces between all layers. Heat loss is measured across one of the layers whose thermal conductivity had already been well established using laboratory experiments. This value is used to deduce the thermal conductivity of other layers. Three interior temperature levels were considered; namely, 300°C, 500°C, and 700°C. Results show that the thermal conductivity of insulating firebrick remains low (approximately 0.22 W/m.K) at an average layer temperature as high as 640°C, but it was evident that the addition of mortar had an impact on its effective thermal conductivity. Results also show that the thermal conductivity of perlite concrete is very low, approximately 0.15 W/m.K at an average layer temperature of 360°C. This is evident by the large temperature drop that occurs across the perlite concrete layer. These results should be useful for future studies, especially those that focus on numerical modeling of TES bins.

  18. Innovative Miniaturized Heat Pumps for Buildings: Modular Thermal Hub for Building Heating, Cooling and Water Heating

    SciTech Connect

    2010-09-01

    BEETIT Project: Georgia Tech is using innovative components and system design to develop a new type of absorption heat pump. Georgia Tech’s new heat pumps are energy efficient, use refrigerants that do not emit greenhouse gases, and can run on energy from combustion, waste heat, or solar energy. Georgia Tech is leveraging enhancements to heat and mass transfer technology possible in microscale passages and removing hurdles to the use of heat-activated heat pumps that have existed for more than a century. Use of microscale passages allows for miniaturization of systems that can be packed as monolithic full-system packages or discrete, distributed components enabling integration into a variety of residential and commercial buildings. Compared to conventional heat pumps, Georgia Tech’s design innovations will create an absorption heat pump that is much smaller, has higher energy efficiency, and can also be mass produced at a lower cost and assembly time.

  19. High-resolution QWIP thermal imager for AFV upgrade

    NASA Astrophysics Data System (ADS)

    Dahlberg, Anders G. M.

    2004-08-01

    Following on the success of the BIRC clip on thermal imaging sight for the BILL Anti-Tank Missile System, which was in fact the world's first military QWIP based thermal imager, and which has been successfully delivered to the Swedish Army in serial quantities, several new QWIP-based products from FLIR Systems AB in Sweden are now under contract for defense customers worldwide. These include the new Forward Observation Systems for Norway and Sweden, Airborne Search & Rescue Systems, and a new clip on thermal imager for the Bofors RBS 70 Air Defense Missile System. The latest of these products is the development of a High Resolution QWIP Thermal Imager, LIRC, under contract for an upgrade of a number of Swedish CV9040C Armored Fighting Vehicles for Swedish Army International Operations. The paper will focus on the rationale behind the system selection, the development of the military qualified QWIP Thermal Imagers and the current status of the program.

  20. Thermal Transport in High-Strength Polymethacrylimide (PMI) Foam Insulations

    NASA Astrophysics Data System (ADS)

    Qiu, L.; Zheng, X. H.; Zhu, J.; Tang, D. W.; Yang, S. Y.; Hu, A. J.; Wang, L. L.; Li, S. S.

    2015-11-01

    Thermal transport in high-strength polymethacrylimide (PMI) foam insulations is described, with special emphasis on the density and temperature effects on the thermal transport performance. Measurements of the effective thermal conductivity are performed by a freestanding sensor-based 3ω method. A linear relationship between the density and the effective thermal conductivity is observed. Based on the analysis of the foam insulation morphological structures and the corresponding geometrical cell model, the quantitative contribution of the solid conductivity and the gas conductivity as well as the radiative conductivity to the total effective thermal conductivity as a function of the density and temperature is calculated. The agreement between the curves of the results from the developed model and experimental data indicate the model can be used for PMI foam insulating performance optimization.

  1. OVERVIEW OF CONVENTIONAL AND INNOVATIVE LAND-BASED THERMAL TECHNOLOGIES FOR WASTE DISPOSAL

    EPA Science Inventory

    For more than the past two decades, the USEPA has been aggressive in its research, development, performance testing, and in encouragement of the regulated use of proven thermal destruction (or incineration) technologies for the environmentally acceptable treatment and disposal of...

  2. Development and Demonstration of an Innovative Thermal Energy Storage System for Baseload Power Generation

    SciTech Connect

    Goswami, D. Yogi

    2012-09-04

    The objective of this project is to research and develop a thermal energy storage system (operating range 300°C - 450°C) based on encapsulated phase change materials (PCM) that can meet the utility-scale base-load concentrated solar power plant requirements at much lower system costs compared to the existing thermal energy storage (TES) concepts. The major focus of this program is to develop suitable encapsulation methods for existing low-cost phase change materials that would provide a cost effective and reliable solution for thermal energy storage to be integrated in solar thermal power plants. This project proposes a TES system concept that will allow for an increase of the capacity factor of the present CSP technologies to 75% or greater and reduce the cost to less than $20/kWht.

  3. Detection of a buried horizon with a high thermal diffusivity using thermal remote sensing

    NASA Technical Reports Server (NTRS)

    Nash, David B.

    1988-01-01

    A field investigation using thermal remote sensing was performed to test the feasibility of detecting the surface topography of granite bedrock beneath a thin cover of alluvium. Imagery of a region of the Mojave Desert were taken with an airborne multispectral scanner with thermal spectral bandwidths of 10.4 and 12.5 microns an instantaneous field of view of 2.5 mrad. It is suggested that a buried high thermal diffusivity horizon measurably lowers the surface temperature of the overlying lower diffusivity material during the peak of the annual heating cycle.

  4. Highly directional thermal emission from two-dimensional silicon structures.

    PubMed

    Ribaudo, Troy; Peters, David W; Ellis, A Robert; Davids, Paul S; Shaner, Eric A

    2013-03-25

    We simulate, fabricate, and characterize near perfectly absorbing two-dimensional grating structures in the thermal infrared using heavily doped silicon (HdSi) that supports long wave infrared surface plasmon polaritons (LWIR SPP's). The devices were designed and optimized using both finite difference time domain (FDTD) and rigorous coupled wave analysis (RCWA) simulation techniques to satisfy stringent requirements for thermal management applications requiring high thermal radiation absorption over a narrow angular range and low visible radiation absorption over a broad angular range. After optimization and fabrication, characterization was performed using reflection spectroscopy and normal incidence emissivity measurements. Excellent agreement between simulation and experiment was obtained. PMID:23546065

  5. Design of a High Thermal Gradient Bridgman Furnace

    NASA Technical Reports Server (NTRS)

    LeCroy, J. E.; Popok, D. P.

    1994-01-01

    The Advanced Automated Directional Solidification Furnace (AADSF) is a Bridgman-Stockbarger microgravity processing facility, designed and manifested to first fly aboard the second United States Microgravity Payload (USMP-2) Space Shuttle mission. The AADSF was principally designed to produce high axial thermal gradients, and is particularly suitable for metals solidification experiments, including non-dilute alloys. To accommodate a wider range of experimental conditions, the AADSF is equipped with a reconfigurable gradient zone. The overall design of the AADSF and the relationship between gradient zone design and furnace performance are described. Parametric thermal analysis was performed and used to select gradient zone design features that fulfill the high thermal gradient requirements of the USMP-2 experiment. The thermal model and analytical procedure, and parametric results leading to the first flight gradient zone configuration, are presented. Performance for the USMP-2 flight experiment is also predicted, and analysis results are compared to test data.

  6. High pressure elasticity and thermal properties of depleted uranium

    NASA Astrophysics Data System (ADS)

    Jacobsen, M. K.; Velisavljevic, N.

    2016-04-01

    Studies of the phase diagram of uranium have revealed a wealth of high pressure and temperature phases. Under ambient conditions the crystal structure is well defined up to 100 gigapascals (GPa), but very little information on thermal conduction or elasticity is available over this same range. This work has applied ultrasonic interferometry to determine the elasticity, mechanical, and thermal properties of depleted uranium to 4.5 GPa. Results show general strengthening with applied load, including an overall increase in acoustic thermal conductivity. Further implications are discussed within. This work presents the first high pressure studies of the elasticity and thermal properties of depleted uranium metal and the first real-world application of a previously developed containment system for making such measurements.

  7. Applications of high thermal conductivity composites to electronics and spacecraft thermal design

    NASA Technical Reports Server (NTRS)

    Sharp, G. Richard; Loftin, Timothy A.

    1990-01-01

    Recently, high thermal conductivity continuous graphite fiber reinforced metal matrix composites (MMC's) have become available that can save much weight over present methods of heat conduction. These materials have two or three times higher thermal conductivity in the fiber direction than the pure metals when compared on a thermal conductivity to weight basis. Use of these materials for heat conduction purposes can result in weight savings of from 50 to 70 percent over structural aluminum. Another significant advantage is that these materials can be used without the plumbing and testing complexities that accompany the use of liquid heat pipes. A spinoff of this research was the development of other MMC's as electronic device heat sinks. These use particulates rather than fibers and are formulated to match the coefficient of thermal expansion of electronic substrates in order to alleviate thermally induced stresses. The development of both types of these materials as viable weight saving substitutes for traditional methods of thermal control for electronics packaging and also for spacecraft thermal control applications are the subject of this report.

  8. High Road Partnerships Report: Innovations in Building Good Jobs and Strong Communities.

    ERIC Educational Resources Information Center

    American Federation of Labor and Congress of Industrial Organizations, Washington, DC. Working for America Inst.

    When deciding how to compete in the new global economy, employers can opt for "low-road" strategies such as low wages and no job security. Alternatively, they can choose the "high road" and compete by offering quality goods and services, innovation, and value. Fourteen successful "high-road" partnerships were examined to identify elements likely…

  9. Innovative Methodologies for thermal Energy Release Measurement: case of La Solfatara volcano (Italy)

    NASA Astrophysics Data System (ADS)

    Marfe`, Barbara; Avino, Rosario; Belviso, Pasquale; Caliro, Stefano; Carandente, Antonio; Marotta, Enrica; Peluso, Rosario

    2015-04-01

    This work is devoted to improve the knowledge on the parameters that control the heat flux anomalies associated with the diffuse degassing processes of volcanic and hydrothermal areas. The methodologies currently used to measure heat flux (i.e. CO2 flux or temperature gradient) are either poorly efficient or effective, and are unable to detect short to medium time (days to months) variation trends in the heat flux. A new method, based on the use of thermal imaging cameras, has been applied to estimate the heat flux and its time variations. This approach will allow faster heat flux measurement than already accredited methods, improving in this way the definition of the activity state of a volcano and allowing a better assessment of the related hazard and risk mitigation. The idea is to extrapolate the heat flux from the ground surface temperature that, in a purely conductive regime, is directly correlated to the shallow temperature gradient. We use thermal imaging cameras, at short distances (meters to hundreds of meters), to quickly obtain a mapping of areas with thermal anomalies and a measure of their temperature. Preliminary studies have been carried out throughout the whole of the La Solfatara crater in order to investigate a possible correlation between the surface temperature and the shallow thermal gradient. We have used a FLIR SC640 thermal camera and K type thermocouples to assess the two measurements at the same time. Results suggest a good correlation between the shallow temperature gradient ΔTs and the surface temperature Ts depurated from background, and despite the campaigns took place during a period of time of a few years, this correlation seems to be stable over the time. This is an extremely motivating result for a further development of a measurement method based only on the use of small range thermal imaging camera. Surveys with thermal cameras may be manually done using a tripod to take thermal images of small contiguous areas and then joining

  10. Thermal Conductivity Measurements in Metals at High Pressures and Temperatures.

    NASA Astrophysics Data System (ADS)

    Konopkova, Z.; McWilliams, R. S.; Goncharov, A.

    2014-12-01

    The transport properties of iron and iron alloys at high pressures and temperatures are crucial parameters in planetary evolution models, yet are difficult to determine both theoretically and experimentally. Estimates of thermal conductivity in the Earth's core range from 30 to 150 W/mK, a substantial range leaving many open questions regarding the age of the inner core, the thermal structure of the outer core, and the conditions for a working geodynamo. Most experiments have measured electrical resistivity rather than directly measuring thermal conductivity, and have used models to extrapolate from low-temperature data to the high temperature conditions of the core. Here we present direct, in-situ high-pressure and high-temperature measurements of the thermal conductivity of metals in the diamond-anvil cell. Double-sided continuous laser heating is combined with one-side flash heating of a metallic foil, while the time-resolved temperature is measured from both sides with spectral radiometry in an optical streak camera. Emission and temperature perturbations measured on opposite sides of the foil were modeled using finite element calculations in order to extract thermal diffusivity and conductivity of foils. Results on platinum and iron at high pressures and temperatures will be presented.

  11. Thermal design and flight validation for high precision camera

    NASA Astrophysics Data System (ADS)

    Meng, Henghui; Sun, Lixia; Zhang, Chuanqiang; Geng, Liyin

    2015-10-01

    High precision camera, designed for advanced optical system, with a wide field of vision, high resolution and fast response, has a wild range of applications. As the main payload for spacecraft, the optical remote sensor is mounted exposed to the space, which means it should have a reliable optical performance in harsh space environment during lifetime. Because of the special optical characteristic, imaging path should be accurate, and less thermal deformation for the optical parts is required in the working process, so the high precision camera has a high level requirement for temperature. High resolution space camera is generally required to own the capability of adapting to space thermal environments. The flexible satellite's change of rolling attitude affects the temperature distribution of the camera and makes a difference to optical performance. The thermal control design of space camera is presented, and analysis the temperature data in orbit to prove the thermal design correct. It is proved that the rolling attitude has more influence on outer parts and less influence on inner parts, and active thermal control can weaken the influence of rolling attitude.

  12. High-Efficiency Solar Thermal Vacuum Demonstration Completed for Refractive Secondary Concentrator

    NASA Technical Reports Server (NTRS)

    Wong, Wayne A.

    2001-01-01

    Common to many of the space applications that utilize solar thermal energy--such as electric power conversion, thermal propulsion, and furnaces--is a need for highly efficient, solar concentration systems. An effort is underway at the NASA Glenn Research Center to develop the refractive secondary concentrator, which uses refraction and total internal reflection to efficiently concentrate and direct solar energy. When used in combination with advanced lightweight primary concentrators, the refractive secondary concentrator enables very high system concentration ratios (10,000 to 1) and very high temperatures (>2000 K). The innovative refractive secondary concentrator offers significant advantages over all other types of secondary concentrators. The refractive secondary offers the highest throughput efficiency, provides for flux tailoring, requires no active cooling, relaxes the pointing and tracking requirements of the primary concentrator, and enables very high system concentration ratios. This technology has broad applicability to any system that requires the conversion of solar energy to heat. Glenn initiated the development of the refractive secondary concentrator in support of Shooting Star, a solar thermal propulsion flight experiment, and continued the development in support of Space Solar Power.

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

    NASA Technical Reports Server (NTRS)

    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.

  14. Measurement of thermal diffusivity of rocks at high pressure

    SciTech Connect

    Mirkovich, V.V.; Durham, W.B.; Heard, H.C.

    1982-10-01

    A method for measurement of thermal diffusivity at high hydrostatic pressure was developed by adapting a radial symmetry heat flow method wherein a sinusoidal heat wave is applied to the cylindrical surface of the sample. The accuracy of the measuring system was tested using Pyroceram 9606. Data obtained were within 5% of published values at all temperatures to 400/sup 0/C and no dependence upon pressure was observed. Thermal diffusivity of three crystalline igneous rock specimens was measured at temperatures from 32 to 400/sup 0/C and pressures from 0.1 to 200 MPa. The results for Creighton quartz diorite showed only limited temperature and pressure dependence. In the case of Stripa and Westerly granites, this dependence was found to be more substantial. Thermal diffusivity of Stripa granite decreased by more than 50% from 32 to 400/sup 0/C and that of Westerly granite decreased by approximately 40% over the same range. At 32/sup 0/C and 200 MPa, thermal diffusivity for both rocks was higher by approximately 10% than that measured at 0.1 MPa. At higher temperatures the difference in thermal diffusivity between the two pressure levels increased. An anomaly was observed in Stripa and Westerly granite in the temperature range 32 to 65/sup 0/C: thermal diffusivity increased with increasing temperature. The anomaly is consistent with recently observed thermal expansivity in these rocks as a function of pressure and temperature.

  15. Highly thermally conductive papers with percolative layered boron nitride nanosheets.

    PubMed

    Zhu, Hongli; Li, Yuanyuan; Fang, Zhiqiang; Xu, Jiajun; Cao, Fangyu; Wan, Jiayu; Preston, Colin; Yang, Bao; Hu, Liangbing

    2014-04-22

    In this work, we report a dielectric nanocomposite paper with layered boron nitride (BN) nanosheets wired by one-dimensional (1D) nanofibrillated cellulose (NFC) that has superior thermal and mechanical properties. These nanocomposite papers are fabricated from a filtration of BN and NFC suspensions, in which NFC is used as a stabilizer to stabilize BN nanosheets. In these nanocomposite papers, two-dimensional (2D) nanosheets form a thermally conductive network, while 1D NFC provides mechanical strength. A high thermal conductivity has been achieved along the BN paper surface (up to 145.7 W/m K for 50 wt % of BN), which is an order of magnitude higher than that in randomly distributed BN nanosheet composites and is even comparable to the thermal conductivity of aluminum alloys. Such a high thermal conductivity is mainly attributed to the structural alignment within the BN nanosheet papers; the effects of the interfacial thermal contact resistance are minimized by the fact that the heat transfer is in the direction parallel to the interface between BN nanosheets and that a large contact area occurs between BN nanosheets. PMID:24601534

  16. Investigation of Thermal High Cycle and Low Cycle Fatigue Mechanisms of Thick Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Miller, Robert A.

    1998-01-01

    Thick thermal barrier coating systems in a diesel engine experience severe thermal low cycle fatigue (LCF) and high cycle fatigue (HCF) during engine operation. In this paper, the mechanisms of fatigue crack initiation and propagation in a ZrO2-8wt% Y2O3 thermal barrier coating, under simulated engine thermal LCF and HCF conditions, are investigated using a high power CO2 laser. Experiments showed that the combined LCF-HCF tests induced more severe coating surface cracking, microspallation and accelerated crack growth, as compared to the pure LCF test. Lateral crack branching and the ceramic/bond coat interface delaminations were also facilitated by HCF thermal loads, even in the absence of severe interfacial oxidation. Fatigue damage at crack wake surfaces, due to such phenomena as asperity/debris contact induced cracking and splat pull-out bending during cycling, was observed especially for the combined LCF-HCF tests. It is found that the failure associated with LCF is closely related to coating sintering and creep at high temperatures, which induce tensile stresses in the coating after cooling. The failure associated with HCF process, however, is mainly associated with a surface wedging mechanism. The interaction between the LCF, HCF and ceramic coating creep, and the relative importance of LCF and HCF in crack propagation are also discussed based on the experimental evidence.

  17. Investigation of Thermal High Cycle and Low Cycle Fatigue Mechanisms of Thick Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Miller, Robert A.

    1998-01-01

    Thick thermal barrier coating systems in a diesel engine experience severe thermal low cycle fatigue (LCF) and high cycle fatigue (HCF) during engine operation. In this paper, the mechanisms of fatigue crack initiation and propagation in a ZrO2-8wt.% Y2O3 thermal barrier coating, under simulated engine thermal LCF and HCF conditions, are investigated using a high power CO2 laser. Experiments showed that the combined LCF/HCF tests induced more severe coating surface cracking, microspallation and accelerated crack growth, as compared to the pure LCF test. Lateral crack branching and the ceramic/bond coat interface delaminations were also facilitated by HCF thermal loads, even in the absence of severe interfacial oxidation. Fatigue damages at crack wake surfaces, due to such phenomena as asperity/debris contact induced cracking and splat pull-out bending during cycling, were observed especially for the combined LCF/HCF tests. It is found that the failure associated with LCF is closely related to coating sintering and creep at high temperatures, which induce tensile stresses in the coating after cooling. The failure associated with HCF process, however, is mainly associated with a surface wedging mechanism. The interaction between the LCF, HCF and ceramic coating creep, and the relative importance of LCF and HCF in crack propagation are also discussed based on the experimental evidence.

  18. Innovation in Student Services: Planning for Models Blending High Touch/High Tech.

    ERIC Educational Resources Information Center

    Burnett, Darlene J., Ed.; Oblinger, Diana G., Ed.

    This collection is intended to help planners, administrators, and student service professionals gain a better understanding of the changes emerging in student services as it demonstrates how innovative leaders are responding to these challenges. Part 1, "Creating the Student-Centered Experience," contains: (1) "Innovation in Student Services" Best…

  19. Wooden concrete: High thermal efficiency using waste wood

    SciTech Connect

    Kosny, J.

    1994-09-01

    Wood concrete mixture of wood shavings, lime and cement is widely used in European building construction. In spite of many advantages, this material is almost unknown in the US. Eventual application of wooden concrete in building block production is discussed in this paper. Based on finite difference computer modeling, the thermal performance of several masonry wall systems and their components have been analyzed. The total wall system thermal performance for a typical single-story ranch house also has been determined. At present, typical experimental wall measurements and calculations do not include the effects of building envelope subsystems such as comers, window and door openings, and structural joints with roofs, floors, ceilings, and other walls. In masonry wall systems, these details may represent significant thermal bridges because of the highly conductive structural concrete. Many of the typical thermal bridges may be reduced by application of wood concrete elements.

  20. Adoption of a High-Impact Innovation in a Homogeneous Population

    NASA Astrophysics Data System (ADS)

    Weiss, Curtis H.; Poncela-Casasnovas, Julia; Glaser, Joshua I.; Pah, Adam R.; Persell, Stephen D.; Baker, David W.; Wunderink, Richard G.; Nunes Amaral, Luís A.

    2014-10-01

    Adoption of innovations, whether new ideas, technologies, or products, is crucially important to knowledge societies. The landmark studies of adoption dealt with innovations having great societal impact (such as antibiotics or hybrid crops) but where determining the utility of the innovation was straightforward (such as fewer side effects or greater yield). Recent large-scale studies of adoption were conducted within heterogeneous populations and focused on products with little societal impact. Here, we focus on a case with great practical significance: adoption by small groups of highly trained individuals of innovations with large societal impact but for which it is impractical to determine the true utility of the innovation. Specifically, we study experimentally the adoption by critical care physicians of a diagnostic assay that complements current protocols for the diagnosis of life-threatening bacterial infections and for which a physician cannot estimate the true accuracy of the assay based on personal experience. We show through computational modeling of the experiment that infection-spreading models—which have been formalized as generalized contagion processes—are not consistent with the experimental data, while a model inspired by opinion models is able to reproduce the empirical data. Our modeling approach enables us to investigate the efficacy of different intervention schemes on the rate and robustness of innovation adoption in the real world. While our study is focused on critical care physicians, our findings have implications for other settings in education, research, and business, where small groups of highly qualified peers make decisions about the adoption of innovations whose utility is difficult if not impossible to gauge.

  1. Adoption of a High-Impact Innovation in a Homogeneous Population.

    PubMed

    Weiss, Curtis H; Poncela-Casasnovas, Julia; Glaser, Joshua I; Pah, Adam R; Persell, Stephen D; Baker, David W; Wunderink, Richard G; Nunes Amaral, Luís A

    2014-10-15

    Adoption of innovations, whether new ideas, technologies, or products, is crucially important to knowledge societies. The landmark studies of adoption dealt with innovations having great societal impact (such as antibiotics or hybrid crops) but where determining the utility of the innovation was straightforward (such as fewer side effects or greater yield). Recent large-scale studies of adoption were conducted within heterogeneous populations and focused on products with little societal impact. Here, we focus on a case with great practical significance: adoption by small groups of highly trained individuals of innovations with large societal impact but for which it is impractical to determine the true utility of the innovation. Specifically, we study experimentally the adoption by critical care physicians of a diagnostic assay that complements current protocols for the diagnosis of life-threatening bacterial infections and for which a physician cannot estimate the true accuracy of the assay based on personal experience. We show through computational modeling of the experiment that infection-spreading models-which have been formalized as generalized contagion processes-are not consistent with the experimental data, while a model inspired by opinion models is able to reproduce the empirical data. Our modeling approach enables us to investigate the efficacy of different intervention schemes on the rate and robustness of innovation adoption in the real world. While our study is focused on critical care physicians, our findings have implications for other settings in education, research, and business, where small groups of highly qualified peers make decisions about the adoption of innovations whose utility is difficult if not impossible to gauge. PMID:25392742

  2. Thermal stability of high temperature structural alloys

    SciTech Connect

    Jordan, C.E.; Rasefske, R.K.; Castagna, A.

    1999-03-01

    High temperature structural alloys were evaluated for suitability for long term operation at elevated temperatures. The effect of elevated temperature exposure on the microstructure and mechanical properties of a number of alloys was characterized. Fe-based alloys (330 stainless steel, 800H, and mechanically alloyed MA 956), and Ni-based alloys (Hastelloy X, Haynes 230, Alloy 718, and mechanically alloyed MA 758) were evaluated for room temperature tensile and impact toughness properties after exposure at 750 C for 10,000 hours. Of the Fe-based alloys evaluated, 330 stainless steel and 800H showed secondary carbide (M{sub 23}C{sub 6}) precipitation and a corresponding reduction in ductility and toughness as compared to the as-received condition. Within the group of Ni-based alloys tested, Alloy 718 showed the most dramatic structure change as it formed delta phase during 10,000 hours of exposure at 750 C with significant reductions in strength, ductility, and toughness. Haynes 230 and Hastelloy X showed significant M{sub 23}C{sub 6} carbide precipitation and a resulting reduction in ductility and toughness. Haynes 230 was also evaluated after 10,000 hours of exposure at 850, 950, and 1050 C. For the 750--950 C exposures the M{sub 23}C{sub 6} carbides in Haynes 230 coarsened. This resulted in large reductions in impact strength and ductility for the 750, 850 and 950 C specimens. The 1050 C exposure specimens showed the resolution of M{sub 23}C{sub 6} secondary carbides, and mechanical properties similar to the as-received solution annealed condition.

  3. Process for fabricating composite material having high thermal conductivity

    DOEpatents

    Colella, Nicholas J.; Davidson, Howard L.; Kerns, John A.; Makowiecki, Daniel M.

    2001-01-01

    A process for fabricating a composite material such as that having high thermal conductivity and having specific application as a heat sink or heat spreader for high density integrated circuits. The composite material produced by this process has a thermal conductivity between that of diamond and copper, and basically consists of coated diamond particles dispersed in a high conductivity metal, such as copper. The composite material can be fabricated in small or relatively large sizes using inexpensive materials. The process basically consists, for example, of sputter coating diamond powder with several elements, including a carbide forming element and a brazeable material, compacting them into a porous body, and infiltrating the porous body with a suitable braze material, such as copper-silver alloy, thereby producing a dense diamond-copper composite material with a thermal conductivity comparable to synthetic diamond films at a fraction of the cost.

  4. Research on Innovative Practice Teaching System Based on the High-End Practice Teaching Environment for Software Engineering Speciality

    NASA Astrophysics Data System (ADS)

    Dong, Jianli; Li, Cunhua; Ji, Zhaohui; Wu, Junming

    Through the analysis of current culture status of undergraduate engineering applied talents, the paper points out that the main reason causing the lack of student integrated application and practice innovation abilities is the poor construction of high-end practice environment. And then, how to enhance the practice environment construction and practical teaching innovation as well as building an appropriate innovation practice teaching system for engineering applied talents are systematically discussed. It is very obvious that the application and promotion of this kind of innovative practice teaching system could enhance the practice innovation abilities and entrepreneurial and employment awareness of the graduates.

  5. Thermal Expansion and Thermophysical Properties of Materials and Minerals at High Temperature and High Pressure

    NASA Astrophysics Data System (ADS)

    Wang, Kai

    1995-11-01

    The knowledge of thermal expansion at high temperature and high pressure is necessary for modeling the equation of the state in the Earth's interior. It is an important parameter for materials science and is critical for understanding the nature of the residual stress in materials. Also, thermal expansion is a factor in the equations that describe many thermoelastic parameters. Errors in thermal expansion will propagate in thermodynamic calculations. This dissertation is based on a semi-empirical, quasi-harmonic, lattice dynamic thermal expansion model, its extension to high temperatures and high pressures and the role of defects on thermal expansion. A modified quasi -harmonic model is proposed to calculate high temperature thermal expansion of alkali halides. An empirical parabolic relationship is found at high temperatures. The contributions of thermal defects at high temperatures are employed to explain the differences between experimental data and the perfect quasi-harmonic crystal model. Expressions for defect contributions on thermal expansion and expansivity are given and applied to obtain the formation energies of thermal defects. Defect ordering is proposed for ionic crystals at high temperatures. A simplified model is derived for predicting high pressure thermal expansion. A detailed expression for defect contributions at high temperatures and high pressures is provided. Thermal expansion of MgO is predicted for pressures as high as at the core-mantle boundary. This model is also applied to alkali halides, and the thermophysical properties of NaCl are given as an example. Then a general model is proposed for evaluating and predicting high temperature thermal expansion. The product of thermal expansion, bulk modulus, and volume, alpha_{V}K_{T }V, or the partial temperature derivative of the work done by thermal pressure, resembles a specific heat curve. A modified Einstein model is applied to express the alpha_{V}K_{T }V data. After assuming a linear

  6. Thermal conductivity and elastic modulus evolution of thermal barrier coatings under high heat flux conditions

    NASA Astrophysics Data System (ADS)

    Zhu, Dongming; Miller, Robert A.

    2000-06-01

    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 be 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, 1.19, and 1.5 W/m K after 30 h of testing at surface temperatures of 990, 1100, and 1320 °C, respectively, Hardness and elastic 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 microindentation 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 h of 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 microporosity 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 TBC applications.

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

    NASA Technical Reports Server (NTRS)

    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.

  8. Improving SFR Economics Through Innovations from Thermal Design and Analysis Aspects

    SciTech Connect

    Haihua Zhao; Hongbin Zhang; Vincent Mousseau; Per F. Peterson

    2009-06-01

    Achieving economic competitiveness as compared to LWRs and other Generation IV (Gen-IV) reactors is one of the major requirements for large-scale investment in commercial sodium cooled fast reactor (SFR) power plants. Advances in R&D for advanced SFR fuel and structural materials provide key long-term opportunities to improve SFR economics. In addition, other new opportunities are emerging to further improve SFR economics. This paper provides an overview on potential ideas from the perspective of thermal hydraulics to improve SFR economics. These include a new hybrid loop-pool reactor design to further optimize economics, safety, and reliability of SFRs with more flexibility, a multiple reheat and intercooling helium Brayton cycle to improve plant thermal efficiency and reduce safety related overnight and operation costs, and modern multi-physics thermal analysis methods to reduce analysis uncertainties and associated requirements for over-conservatism in reactor design. This paper reviews advances in all three of these areas and their potential beneficial impacts on SFR economics.

  9. Improving SFR Economics through Innovations from Thermal Design and Analysis Aspects

    SciTech Connect

    Haihua Zhao; Hongbin Zhang; Vincent Mousseau; Per F. Peterson

    2008-06-01

    Achieving economic competitiveness as compared to LWRs and other Generation IV (Gen-IV) reactors is one of the major requirements for large-scale investment in commercial sodium cooled fast reactor (SFR) power plants. Advances in R&D for advanced SFR fuel and structural materials provide key long-term opportunities to improve SFR economics. In addition, other new opportunities are emerging to further improve SFR economics. This paper provides an overview on potential ideas from the perspective of thermal hydraulics to improve SFR economics. These include a new hybrid loop-pool reactor design to further optimize economics, safety, and reliability of SFRs with more flexibility, a multiple reheat and intercooling helium Brayton cycle to improve plant thermal efficiency and reduce safety related overnight and operation costs, and modern multi-physics thermal analysis methods to reduce analysis uncertainties and associated requirements for over-conservatism in reactor design. This paper reviews advances in all three of these areas and their potential beneficial impacts on SFR economics.

  10. THERMAL ANALYSIS OF GEOLOGIC HIGH-LEVEL RADIOACTIVE WASTE PACKAGES

    SciTech Connect

    Hensel, S.; Lee, S.

    2010-04-20

    The engineering design of disposal of the high level waste (HLW) packages in a geologic repository requires a thermal analysis to provide the temperature history of the packages. Calculated temperatures are used to demonstrate compliance with criteria for waste acceptance into the geologic disposal gallery system and as input to assess the transient thermal characteristics of the vitrified HLW Package. The objective of the work was to evaluate the thermal performance of the supercontainer containing the vitrified HLW in a non-backfilled and unventilated underground disposal gallery. In order to achieve the objective, transient computational models for a geologic vitrified HLW package were developed by using a computational fluid dynamics method, and calculations for the HLW disposal gallery of the current Belgian geological repository reference design were performed. An initial two-dimensional model was used to conduct some parametric sensitivity studies to better understand the geologic system's thermal response. The effect of heat decay, number of co-disposed supercontainers, domain size, humidity, thermal conductivity and thermal emissivity were studied. Later, a more accurate three-dimensional model was developed by considering the conduction-convection cooling mechanism coupled with radiation, and the effect of the number of supercontainers (3, 4 and 8) was studied in more detail, as well as a bounding case with zero heat flux at both ends. The modeling methodology and results of the sensitivity studies will be presented.

  11. Modeling thermally driven energetic response of high explosives

    SciTech Connect

    Sharp, R; Couch, R; McCallen, R C; Nichols III, A L; Otero, I

    1998-02-01

    We have improved our ability to model the response of energetic materials to thermal stimuli and the processes involved in the energetic response. Traditionally, the analyses of energetic materials have involved coupled thermal transport/chemical reaction codes. This provides only a reasonable estimate of the time and location of ensuing rapid reaction. To predict the violence of the reaction, the mechanical motion must be included in the wide range of time scales associated with the thermal hazard. The ALE3D code has been modified to assess the hazards associated with heating energetic materials in weapons by coupling to thermal transport model and chemistry models. We have developed an implicit time step option to efficiently and accurately compute the hours of heating to reaction of the energetic material. Since, on these longer time scales materials can be expected to have significant motion, it is even more important to provide high-order advection for all components, including the chemical species. We show two examples of coupled thermal/mechanical/chemical models of energetic materials in thermal environments.

  12. Modeling thermally driven energetic response of high explosives

    SciTech Connect

    Couch, R; McCallen, R C; Nichols III, A L; Otero, I; Sharp, R

    1998-08-17

    We have improved our ability to model the response of energetic materials to thermal stimuli and the processes involved in the energetic response. Traditionally, the analyses of energetic materials have involved coupled thermal transport/chemical reaction codes. This provides only a reasonable estimate of the time and location of ensuing rapid reaction. To predict the violence of the reaction, the mechanical motion must be included in the wide range of time scales associated with the thermal hazard. The ALE3D code has been modified to assess the hazards associated with heating energetic materials in weapons by coupling to thermal transport model and chemistry models. We have developed an implicit time step option to efficiently and accurately compute the hours of heating to reaction of the energetic material. Since, on these longer time scales materials can be expected to have significant motion, it is even more important to provide high-order advection for all components, including the chemical species. We show two examples of coupled thermal/mechanical/chemical models of energetic materials in thermal environments.

  13. Thermal design concept for a high resolution UV spectrometer

    NASA Technical Reports Server (NTRS)

    Caruso, P.; Stipandic, E.

    1979-01-01

    The thermal design concept described has been developed for the High Resolution UV Spectrometer/Polarimeter to be flown on the Solar Maximum Mission. Based on experience gained from a similar Orbiting Solar Observatory mission payload, it has been recognized that initial protection of the optical elements, contamination control, reduction of scattered light, tight bulk temperature, and gradient constraints are key elements that must be accommodated in any thermal control concept for this class of instrument. Salient features of the design include: (1) a telescope door providing contamination protection of an aplanatic Gregorian telescope; (2) a rastering system for the secondary mirror; (3) a unique solar heat absorbing device; (4) heat pipes and special radiators; (5) heaters for active temperature control and optics contamination protection; and (6) high precision platinum resistance thermometers. Viability of the design concept has been established by extensive thermal analysis and some subsystem testing. A summary of analytical and test results is included.

  14. Proposal Sets Out "i3" Rules: Education Department Eyeing High Bar in Innovation Grant Awards

    ERIC Educational Resources Information Center

    McNeil, Michele

    2009-01-01

    The U.S. Department of Education is proposing high hurdles for school districts and nonprofit groups that want a piece of the $650 million Investing in Innovation grant program, including evidence of past success in helping students most in need and significant financial commitments from the private sector. The grants, which are meant to expand…

  15. High Fidelity Probe and Mitigation of Mirror Thermal Fluctuations

    NASA Astrophysics Data System (ADS)

    Chalermsongsak, Tara

    Thermal noise arising from mechanical loss in high reflective dielectric coatings is a significant source of noise in precision optical measurements. In particular, Advanced LIGO, a large scale interferometer aiming to observed gravitational wave, is expected to be limited by coating thermal noise in the most sensitive region around 30-300 Hz. Various theoretical calculations for predicting coating Brownian noise have been proposed. However, due to the relatively limited knowledge of the coating material properties, an accurate approximation of the noise cannot be achieved. A testbed that can directly observed coating thermal noise close to Advanced LIGO band will serve as an indispensable tool to verify the calculations, study material properties of the coating, and estimate the detector's performance. This dissertation reports a setup that has sensitivity to observe wide band (10Hz to 1kHz) thermal noise from fused silica/tantala coating at room temperature from fixed-spacer Fabry-Perot cavities. Important fundamental noises and technical noises associated with the setup are discussed. The coating loss obtained from the measurement agrees with results reported in the literature. The setup serves as a testbed to study thermal noise in high reflective mirrors from different materials. One example is a heterostructure of Al xGa1-xAs (AlGaAs). An optimized design to minimize thermo-optic noise in the coating is proposed and discussed in this work.

  16. High-temperature molten salt thermal energy storage systems

    NASA Technical Reports Server (NTRS)

    Petri, R. J.; Claar, T. D.; Tison, R. R.; Marianowski, L. G.

    1980-01-01

    The results of comparative screening studies of candidate molten carbonate salts as phase change materials (PCM) for advanced solar thermal energy storage applications at 540 to 870 C (1004 to 1600 F) and steam Rankine electric generation at 400 to 540 C (752 to 1004 F) are presented. Alkali carbonates are attractive as latent heat storage materials because of their relatively high storage capacity and thermal conductivity, low corrosivity, moderate cost, and safe and simple handling requirements. Salts were tested in 0.1 kWhr lab scale modules and evaluated on the basis of discharge heat flux, solidification temperature range, thermal cycling stability, and compatibility with containment materials. The feasibility of using a distributed network of high conductivity material to increase the heat flux through the layer of solidified salt was evaluated. The thermal performance of an 8 kWhr thermal energy storage (TES) module containing LiKCO3 remained very stable throughout 5650 hours and 130 charge/discharge cycles at 480 to 535 C (896 to 995 F). A TES utilization concept of an electrical generation peaking subsystem composed of a multistage condensing steam turbine and a TES subsystem with a separate power conversion loop was defined. Conceptual designs for a 100 MW sub e TES peaking system providing steam at 316 C, 427 C, and 454 C (600 F, 800 F, and 850 F) at 3.79 million Pa (550 psia) were developed and evaluated. Areas requiring further investigation have also been identified.

  17. Supercritical Water Nuclear Steam Supply System: Innovations In Materials, Neutronics & Thermal-Hydraulics

    SciTech Connect

    Mark Anderson; M.L. Corradini; K. Sridharan; P. WIlson; D. Cho; T.K. Kim; S. Lomperski

    2004-09-02

    In the 1990's supercritical light-water reactors were considered in conceptual designs. A nuclear reactor cooled by supercritical waster would have a much higher thermal efficiency with a once-through direct power cycle, and could be based on standardized water reactor components (light water or heavy water). The theoretical efficiency could be improved by more than 33% over that of other water reactors and could be simplified with higher reliability; e.g., a boiling water reactor without steam separators or dryers.

  18. Fundamental kinetics and innovative applications of nonequilibrium atomic vibration in thermal energy transport and conversion

    NASA Astrophysics Data System (ADS)

    Shin, Seungha

    All energy conversion inefficiencies begin with emission of resonant atomic motions, e.g., vibrations, and are declared as waste heat once these motions thermalize to equilibrium. The nonequilibrium energy occupancy of the vibrational modes can be targeted as a harvestable, low entropy energy source for direct conversion to electric energy. Since the lifetime of these resonant vibrations is short, special nanostructures are required with the appropriate tuning of the kinetics. These in turn require multiscale, multiphysics treatments. Atomic vibration is described with quasiparticle phonon in solid, and the optical phonon emission is dominant relaxation channel in semiconductors. These optical modes become over-occupied when their emission rate becomes larger than their decay rate, thus hindering energy relaxation and transport in devices. Effective removal of these phonons by drifting electrons is investigated by manipulating the electron distribution to have higher population in the low-energy states, thus allowing favorable phonon absorption. This is done through introduction, design and analysis of a heterobarrier conducting current, where the band gap is controlled by alloying, thus creating a spatial variation which is abrupt followed by a linear gradient (to ensure directed current). Self-consistent ensemble Monte Carlo simulations based on interaction kinetics between electron and phonon show that up to 19% of the phonon energy is converted to electric potential with an optimized GaAs/AlxGa1-xAs barrier structure over a range of current and electron densities, and this system is also verified through statistical entropy analysis. This direct energy conversion improves the device performance with lower operation temperature and enhances overall energy conversion efficiency. Through this study, the paradigm for harvesting the resonant atomic vibration is proposed, reversing the general role of phonon as only causing electric potential drop. Fundamentals

  19. Innovative technology summary report: High-speed clamshell pipe cutter

    SciTech Connect

    1998-09-01

    The Hanford Site C Reactor Technology Demonstration Group demonstrated the High-Speed Clamshell Pipe Cutter technology, developed and marketed by Tri Tool Inc. (Rancho Cordova, California). The models demonstrated are portable, split-frame pipe lathes that require minimal radial and axial clearances for severing and/or beveling in-line pipe with ranges of 25 cm to 41 cm and 46 cm to 61 cm nominal diameter. The radial clearance requirement from the walls, floors, or adjacent pipes is 18 cm. The lathes were supplied with carbide insert conversion kits for the cutting bits for the high-speed technique that was demonstrated. Given site-specific factors, this demonstration showed the cost of the improved technology to be approximately 30% higher than the traditional (baseline) technology (oxyacetylene torch) cost of $14,400 for 10 cuts of contaminated 41-cm and 61-cm-diameter pipe at C Reactor. Actual cutting times were faster than the baseline technology; however, moving/staging the equipment took longer. Unlike the baseline torch, clamshell lathes do not involve applied heat, flames, or smoke and can be operated remotely, thereby helping personal exposures to be as low as reasonably achievable. The baseline technology was demonstrated at the C Reactor north and south water pipe tunnels August 19--22, 1997. The improved technology was demonstrated in the gas pipe tunnel December 15--19.

  20. GPS World, Innovation: Autonomous Navigation at High Earth Orbits

    NASA Technical Reports Server (NTRS)

    Bamford, William; Winternitz, Luke; Hay, Curtis

    2005-01-01

    Calculating a spacecraft's precise location at high orbital altitudes-22,000 miles (35,800 km) and beyond-is an important and challenging problem. New and exciting opportunities become possible if satellites are able to autonomously determine their own orbits. First, the repetitive task of periodically collecting range measurements from terrestrial antennas to high altitude spacecraft becomes less important-this lessens competition for control facilities and saves money by reducing operational costs. Also, autonomous navigation at high orbital altitudes introduces the possibility of autonomous station keeping. For example, if a geostationary satellite begins to drift outside of its designated slot it can make orbit adjustments without requiring commands from the ground. Finally, precise onboard orbit determination opens the door to satellites flying in formation-an emerging concept for many scientific space applications. The realization of these benefits is not a trivial task. While the navigation signals broadcast by GPS satellites are well suited for orbit and attitude determination at lower altitudes, acquiring and using these signals at geostationary (GEO) and highly elliptical orbits is much more difficult. The light blue trace describes the GPS orbit at approximately 12,550 miles (20,200 km) altitude. GPS satellites were designed to provide navigation signals to terrestrial users-consequently the antenna array points directly toward the earth. GEO and HE0 orbits, however, are well above the operational GPS constellation, making signal reception at these altitudes more challenging. The nominal beamwidth of a Block II/IIA GPS satellite antenna array is approximately 42.6 degrees. At GEO and HE0 altitudes, most of these primary beam transmissions are blocked by the Earth, leaving only a narrow region of nominal signal visibility near opposing limbs of the earth. This region is highlighted in gray. If GPS receivers at GEO and HE0 orbits were designed to use these

  1. Sintering Characteristics of Multilayered Thermal Barrier Coatings Under Thermal Gradient and Isothermal High Temperature Annealing Conditions

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

    Pyrochlore oxides have most of the relevant attributes for use as next generation thermal barrier coatings such as phase stability, low sintering kinetics and low thermal conductivity. One of the issues with the pyrochlore oxides is their lower toughness and therefore higher erosion rate compared to the current state-of-the-art TBC material, yttria (6 to 8 wt%) stabilized zirconia (YSZ). In this work, sintering characteristics were investigated for novel multilayered coating consisted of alternating layers of pyrochlore oxide viz Gd2Zr2O7 and t' low k (rare earth oxide doped YSZ). Thermal gradient and isothermal high temperature (1316 C) annealing conditions were used to investigate sintering and cracking in these coatings. The results are then compared with that of relevant monolayered coatings and a baseline YSZ coating.

  2. Long-duration thermal storage for solar-thermal high-pressure steam IPH

    SciTech Connect

    Copeland, R.J.; Stern, C.; Leach, J.W.

    1982-12-01

    Solar-thermal central-receiver systems are cost effective for electric-power and industrial process-heat applications. Systems employing molten nitrate salt as both receiver working fluid and storage have previously been evaluated for diurnal thermal storage. This study evaluates the potential of employing a molten salt receiver for a baseload industrial process plant requiring saturated steam at 68 atm (1000 psi). Two types of thermal storage are evaluated: molten salt, and air and rock. When thermal storage of six hours or less is used, molten nitrate salt alone is the optimum storage. For more than six hours, the optimum storage is a combination of molten salt and air and rock. The air and rock system uses a molten-salt-to-air heat exchanger and a thermocline rock bed heated and cooled by the air. The economic potential of the system is determined. The results depend on the relative cost of fossil fuel and the solar thermal energy costs. The optimum quantity of storage is highly variable, and the range is from no storage to a long duration capacity - 48 hours.

  3. Metal stud wall systems -- Thermal disaster, or modern wall systems with highly efficient thermal insulation?

    SciTech Connect

    Kosny, J.; Christian, J.E.; Desjarlais, A.O.

    1997-11-01

    Because steel has higher thermal conductivity than wood and intense heat transfer occurs through the metal wall components, thermal performances of a metal stud wall are significantly lower than for similar wood stud walls. A reduction of the in-cavity R-value caused by the wood studs is about 10% in wood stud walls. That is why metal stud walls are believed to be considerably less thermally effective than similar made of wood. However, properly designed metal stud walls can be as thermally effective as wood stud walls. Relatively high R-values may be achieved by installing insulating sheathing, which is widely used as a remedy for a weak thermal performance of metal stud walls. A series of the promising metal stud wall configurations is analyzed using results of finite difference computer modeling and guarded hotbox tests. Some of these walls were designed and tested in the ORNL Building Technology Center, some were tested in other laboratories, and some walls were developed and forgotten long time ago. Also, a novel concept of combined foam-metal studs is considered. The main aim of the present paper is to prove that it is possible to build metal stud walls which perform as well as wood stud walls. The key lies in designing; metal stud wall systems have to be treated in a special way with particular consideration to the high thermal conduction of metal components. In the discussed collection of the efficient metal stud wall configurations, reductions of the in-cavity R-value caused by metal studs are between 10 and 20%.

  4. Glass ceramics for sealing to high-thermal-expansion metals

    SciTech Connect

    Wilder, Jr., J. A.

    1980-10-01

    Glass ceramics were studied, formulated in the Na/sub 2/O CaO.P/sub 2/O/sub 5/, Na/sub 2/O.BaOP/sub 2/O/sub 5/, Na/sub 2/O.Al/sub 2/O/sub 3/.P/sub 2/O/sub 5/, and Li/sub 2/O.BaO.P/sub 2/O/sub 5/ systems to establish their suitability for sealing to high thermal expansion metals, e.g. aluminum, copper, and 300 series stainless steels. Glass ceramics in Na/sub 2/O.CaO.P/sub 2/O/sub 5/ and Na/sub 2/O.BaO.P/sub 2/O/sub 5/ systems have coefficients of thermal expansion in the range 140 x 10/sup -1/ per /sup 0/C less than or equal to ..cap alpha.. less than or equal to 225 x 10/sup -7/ per /sup 0/C and fracture toughness values generally greater than those of phosphate glasses; they are suitable for fabricating seals to high thermal expansion metals. Crystal phases include NaPo/sub 3/, (NaPO/sub 3/)/sub 3/, NaBa(PO/sub 3/)/sub 3/, and NaCa(PO/sub 3/)/sub 3/. Glass ceramics formed in the Na/sub 2/O.Al/sub 2/O/sub 3/.P/sub 2/O/sub 5/ systems have coefficients of thermal expansion greater than 240 x 10/sup -7/ per /sup 0/C, but they have extensive microcracking. Due to their low thermal expansion values (..cap alpha.. less than or equal to 120 x 10/sup -7/ per /sup 0/C), glass ceramics in the Li/sub 2/O.BaO.P/sub 2/O/sub 5/ system are unsuitable for sealing to high thermal expansion metals.

  5. Electromagnetic inhibition of high frequency thermal bonding machine

    NASA Astrophysics Data System (ADS)

    He, Hong; Zhang, Qing-qing; Li, Hang; Zhang, Da-jian; Hou, Ming-feng; Zhu, Xian-wei

    2011-12-01

    The traditional high frequency thermal bonding machine had serious radiation problems at dominant frequency, two times frequency and three times frequency. Combining with its working principle, the problems of electromagnetic compatibility were studied, three following measures were adopted: 1.At the head part of the high frequency thermal bonding machine, resonant circuit attenuator was designed. The notch groove and reaction field can make the radiation being undermined or absorbed; 2.The electromagnetic radiation shielding was made for the high frequency copper power feeder; 3.Redesigned the high-frequency oscillator circuit to reduce the output of harmonic oscillator. The test results showed that these measures can make the output according with the national standard of electromagnetic compatibility (GB4824-2004-2A), the problems of electromagnetic radiation leakage can be solved, and good social, environmental and economic benefits would be brought.

  6. Analysis of Thermal Expansivity of Solids Under High Pressures

    NASA Astrophysics Data System (ADS)

    Sunil, K.; Singh, P. K.; Sharma, B. S.

    2012-08-01

    For investigating the thermal expansivity of solids under high pressures we have developed a formulation using the relationship between the reciprocal of pressure derivative of bulk modulus and the ratio of pressure and bulk modulus. The formulation presented here satisfies the boundary conditions both at zero-pressure and also in the limit of infinite pressure at extreme compression. A physically acceptable relationship has been obtained between the Anderson-Grüneisen parameter and the pressure derivatives of bulk modulus. The formulation has been applied to determine the pressure dependence of thermal expansivity of NaCl, MgO and the earth lower mantle minerals.

  7. Thermal performance of windows having high solar transmittance

    SciTech Connect

    Rubin, M.; Selkowitz, S.

    1981-07-01

    Antireflected polyester films and low-iron glass sheets have values of solar transmittance that are substantially higher than those of their untreated counterparts. The plastic films utilize coatings to reduce loses due to surface reflectance and the glass is made with low levels of impurities to reduce adsorption within the material itself. The optical and thermal properties of these materials are discussed and the solar and thermal characteristics of windows incorporating high-transmittance glazing layers are derived. Comparisons among these and other types of windows are made on the basis of net energy use for residential buildings in winter.

  8. Thermal management system options for high power space platforms

    NASA Technical Reports Server (NTRS)

    Sadunas, J. A.; Lehtinen, A.; Parish, R.

    1985-01-01

    Thermal Management System (TMS) design options for a high power (75kWe), low earth orbit, multimodule space platform were investigated. The approach taken was to establish a baseline TMS representative of current technology, and to make incremental improvements through successive subsystem trades that lead to a candidate TMS. The TMS trades included centralized and decentralized transport, single-phase and two-phase transport, alternate working fluids, liquid loop and heat pipe radiators, deployed fixed, body mounted and steerable radiators, and thermal storage. The subsystem options were evaluated against criteria such as weight, TMS power requirement, reliability, system isothermality penalty, and growth potential.

  9. High temperature underground thermal energy storage system for solar energy

    NASA Technical Reports Server (NTRS)

    Collins, R. E.

    1980-01-01

    The activities feasibility of high temperature underground thermal storage of energy was investigated. Results indicate that salt cavern storage of hot oil is both technically and economically feasible as a method of storing huge quantities of heat at relatively low cost. One particular system identified utilizes a gravel filled cavern leached within a salt dome. Thermal losses are shown to be less than one percent of cyclically transferred heat. A system like this having a 40 MW sub t transfer rate capability and over eight hours of storage capacity is shown to cost about $13.50 per KWh sub t.

  10. Obtaining high thermally conductive materials by pressing from the granulate

    NASA Astrophysics Data System (ADS)

    Ditts, A.; Revva, I.; Pautova, Y.; Pogrebenkov, V.; Nepochatov, Y.; Galashov, E.; Tarnovskiy, R.

    2015-01-01

    This work contains results of investigation of obtaining high thermally conductive ceramics from commercial powders of aluminum nitride and yttrium oxide by the method of monoaxial compaction of granulate. The principal scheme of preparation is proposed and technological properties of granulate are defined. Compaction conditions for simple items to use as heat removal in microelectronics and power electrical engineering have been established. Investigations of thermophysical properties of obtained ceramics and its structure by the XRD and SEM methods have been carried out. Ceramics with thermal conductivity from 172 to 174 W/m·K has been obtained as result of this work.

  11. Directional solidification at ultra-high thermal gradient

    NASA Technical Reports Server (NTRS)

    Flemings, M. C.; Lee, D. S.; Neff, M. A.

    1980-01-01

    A high gradient controlled solidification (HGC) furnace was designed and operated at gradients up to 1800 C/cm to continuously produce aluminum alloys. Rubber '0' rings for the water cooling chamber were eliminated, while still maintaining water cooling directly onto the solidified metal. An HGC unit for high temperature ferrous alloys was also designed. Successful runs were made with cast iron, at thermal gradients up to 500 C/cm.

  12. High-efficiency photonic crystal narrowband thermal emitters

    NASA Astrophysics Data System (ADS)

    Farfan, G. B.; Su, M. F.; Reda Taha, M. M.; El-Kady, I.

    2010-02-01

    Photonic crystals (PhC) are artificial structures fabricated with a periodicity in the dielectric function. This periodic electromagnetic potential results in creation of energy bandgaps where photon propagation is prohibited. PhC structures have promising use in thermal applications if optimized to operate at specific thermal emission spectrum. Here, novel utilization of optimized PhC's in thermal applications is presented. We demonstrate through numerical simulation the modification of the thermal emission spectrum by a metallic photonic crystal (PhC) to create high-efficiency multispectral thermal emitters. These emitters funnel radiation from a broad emission spectrum associated with a Plancklike distribution into a prescribed narrow emission band. A detailed quantitative evaluation of the spectral and power efficiencies of a PhC thermal emitter and its portability across infrared (IR) spectral bands are provided. We show an optimized tungsten PhC with a predominant narrow-band emission profile with an emitter efficiency that is more than double that of an ideal blackbody and ~65-75% more power-efficiency across the IR spectrum. We also report on using optimal three-dimensional Lincoln log photonic crystal (LL-PhC) emitters for thermophotovoltaic (TPV) generation as opposed to using a passive filtering approach to truncate the broadband thermal source emission to match the bandgap of a photovoltaic (PV) cell. The emitter performance is optimized for the 1-2μm PV band using different PhC materials, specifically copper, silver and gold. The use of the proposed PhC in TPV devices can produce significant energy savings not reported before. The optimal design of the PhC geometry is obtained by implementing a variety of optimization methods integrated with artificial intelligence (AI) algorithms.

  13. High-field thermal transport properties of REBCO coated conductors

    NASA Astrophysics Data System (ADS)

    Bonura, Marco; Senatore, Carmine

    2015-02-01

    The use of REBCO coated conductors (CCs) is envisaged for many applications, extending from power cables to high-field magnets. Whatever the case, thermal properties of REBCO tapes play a key role for the stability of superconducting devices. In this work, we present the first study on the longitudinal thermal conductivity (κ) of REBCO CCs in magnetic fields up to 19 T applied both parallel and perpendicularly to the thermal-current direction. Copper-stabilized tapes from six industrial manufacturers have been investigated. We show that zero-field κ of CCs can be calculated with an accuracy of +/- 15% from the residual resistivity ratio of the stabilizer and the Cu/non-Cu ratio. Measurements performed at high fields have allowed us to evaluate the consistency of the procedures generally used for estimating in-field κ in the framework of the Wiedemann-Franz law from an electrical characterization of the materials. In-field data are intended to provide primary ingredients for the thermal stability analysis of high-temperature superconductor-based magnets.

  14. High conductivity, low cost aluminum composite for thermal management

    SciTech Connect

    Sommer, J.L.

    1997-04-01

    In order to produce an inexpensive packaging material that exhibits high thermal conductivity and low CTE, Technical Research Associates, Inc. (TRA) has shown in Phase I the feasibility of incorporating natural flake graphite in an aluminum matrix. TRA has developed a proprietary coating technique where graphite flakes have been coated with a thin layer of molybdenum/molybdenum carbide (approximately 0.2 microns). This barrier coating can protect the graphite flake from chemical reaction and high temperature degradation in molten aluminum silicon alloys. Methods to successfully vacuum infiltrate coated flake with molten aluminum alloys were developed. The resulted metal matrix composites exhibited lower CTE than aluminum metal. The CTE of the composites were significantly lower than aluminum and its alloys. The CTE can potentially be tailored for specific applications. The in plane thermal conductivity was higher than the aluminum matrix alloy. The thermal conductivity and CTE of the composite may be significantly improved by improving the bond strength of the molybdenum coating on the graphite flake. The flake can potentially be incorporated in the molten aluminum and pressure die cast to align the flakes within the aluminum matrix. By preferentially aligning high conductivity graphite flakes within a plane or direction, the thermal conductivity of the resulting composite will be above pure aluminum in the alignment direction.

  15. Organic underlayer materials with exceptionally high thermal stability

    NASA Astrophysics Data System (ADS)

    Cheon, Hwan-Sung; Yoon, Kyong-Ho; Kim, Min-Soo; Oh, Sung Bae; Song, Jee-Yun; Tokareva, Nataliya; Kim, Jong-Seob; Chang, Tuwon

    2009-03-01

    Multilayer hardmask (MLHM) schemes have been implemented as an indispensable process for ArF lithography which continues to demand thinner photoresist films. There are many variations of MLHM and semiconductor manufacturers choose to adopt their own designs, depending on their specific needs and technical advances. The quad-layer stack consisting of photoresist, organic ARC, CVD Si hardmask, and spin-on carbon underlayer is one of them. Despite the need for wafer transporting between the spin track and CVD equipment, this scheme is attractive because it can avoid laborious elaboration of sophisticated etching chemistries for spin-on Si-ARC and carbon underlayer. One of the issues arising from the mixed film forming process is the thermal stability of carbon underlayer at high temperatures during the CVD process of the Si hardmask. Organic underlayer which shows high thermal stability is crucial for this mixed hardmask process. These types of thermally stable organic film can also be used for other applications such as the spacer patterning technique for pitch size shrinkage. In this paper, we discuss the development of organic resins with high thermal stability, their physical properties, and their lithographic behaviors in the MLHM schemes.

  16. Applications of heat pipes for high thermal load beam lines

    SciTech Connect

    Shu, D.; Mortazavi, P.; Rarback, H.; Howells, M.R.

    1985-01-01

    The high flux beam produced by insertion devices often requires special heat removal techniques. For the optical elements used in such high thermal load beam lines, the required precision demands a highly accurate design. Heat pipe cooling of critical elements of the X-1 beam line at the National Synchrotron Light Source is described. This method reduces vibrations caused by water cooling systems and simplifies the design. In some of these designs, deposited heat must be transferred through unbonded contact interfaces. A pinhole assembly and a beam position monitor designed for the X-1 beam line both transfer heat through such interfaces in an ultrahigh vacuum environment. The fundamental design objective is that of removing the heat with minimal interface thermal resistance. We present our test method and results for measuring the thermal resistance across metallic interfaces as a function of contact pressure. The design of some devices which utilize both heat pipes and thermal contact interfaces will also be described. 12 refs., 8 figs.

  17. Thermal lensing compensation optics for high power lasers

    NASA Astrophysics Data System (ADS)

    Scaggs, Michael; Haas, Gil

    2011-03-01

    Athermalization of focusing objectives is a common technique for optimizing imaging systems in the infrared where thermal effects are a major concern. The athermalization is generally done within the spectrum of interest and not generally applied to a single wavelength. The predominate glass used with high power infrared lasers in the near infrared of one micron, such as Nd:YAG and fiber lasers, is fused silica which has excellent thermal properties. All glasses, however, have a temperature coefficient of index of refraction (dn/dT) where as the glass heats up its index of refraction changes. Most glasses, fused silica included, have a positive dn/dT. A positive dn/dT will cause the focal length of the lens to decrease with a temperature rise. Many of the fluoride glasses, like CaF2, BaF2, LiF2, etc. have a negative dn/dT. By applying athermalization techniques of glass selection and optical design, the thermal lensing in a laser objective of a high power laser system can be substantially mitigated. We describe a passive method for minimizing thermal lensing of high power laser optics.

  18. IMPULSE---an advanced, high performance nuclear thermal propulsion system

    SciTech Connect

    Petrosky, L.J.; Disney, R.K.; Mangus, J.D. ); Gunn, S.A.; Zweig, H.R. )

    1993-01-10

    IMPULSE is an advanced nuclear propulsion engine for future space missions based on a novel conical fuel. Fuel assemblies are formed by stacking a series of truncated (U, Zr)C cones with non-fueled lips. Hydrogen flows radially inward between the cones to a central plenum connected to a high performance bell nozzle. The reference IMPULSE engine rated at 75,000 lb thrust and 1800 MWt weighs 1360 kg and is 3.65 meters in height and 81 cm in diameter. Specific impulse is estimated to be 1000 for a 15 minute life at full power. If longer life times are required, the operating temperature can be reduced with a concomitant decrease in specific impulse. Advantages of this concept include: well defined coolant paths without outlet flow restrictions; redundant orificing; very low thermal gradients and hence, thermal stresses, across the fuel elements; and reduced thermal stresses because of the truncated conical shape of the fuel elements.

  19. Antioxidant-Based Phase-Change Thermal Interface Materials with High Thermal Stability

    NASA Astrophysics Data System (ADS)

    Aoyagi, Yasuhiro; Chung, D. D. L.

    2008-04-01

    This work provides phase-change thermal interface materials (TIMs) with high thermal stability and high heat of fusion. They are based on antioxidants mainly in the form of hydrocarbons with linear segments. The thermal stability is superior to paraffin wax and four commercial phase-change materials (PCMs). The use of 98.0 wt.% thiopropionate antioxidant (SUMILIZER TP-D) with 2.0 wt.% sterically half-hindered phenolic antioxidant (GA80) as the matrix and the use of 16 vol.% boron nitride particles as the solid component give a PCM with a 100°C lifetime indicator of 5.3 years, in contrast to 0.95 year or less for the commercial PCMs. The heat of fusion is much higher than those of commercial PCMs; the values for antioxidants with nonbranched molecular structures exceed that of wax; the value for one with a branched structure is slightly below that of wax. The phase-change properties are degraded by heating at 150°C much less than those of the commercial PCMs. The stability of the heat of fusion upon phase-change cycling is also superior. The viscosity is essentially unaffected by heating at 150°C. Commercial PCMs give slightly lower values of the thermal contact conductance for the case of rough (12 μm) mating surfaces, in spite of the lower values of the bond-line thickness.

  20. High thermal conductivity of chain-oriented amorphous polythiophene.

    PubMed

    Singh, Virendra; Bougher, Thomas L; Weathers, Annie; Cai, Ye; Bi, Kedong; Pettes, Michael T; McMenamin, Sally A; Lv, Wei; Resler, Daniel P; Gattuso, Todd R; Altman, David H; Sandhage, Kenneth H; Shi, Li; Henry, Asegun; Cola, Baratunde A

    2014-05-01

    Polymers are usually considered thermal insulators, because the amorphous arrangement of the molecular chains reduces the mean free path of heat-conducting phonons. The most common method to increase thermal conductivity is to draw polymeric fibres, which increases chain alignment and crystallinity, but creates a material that currently has limited thermal applications. Here we show that pure polythiophene nanofibres can have a thermal conductivity up to ∼ 4.4 W m(-1) K(-1) (more than 20 times higher than the bulk polymer value) while remaining amorphous. This enhancement results from significant molecular chain orientation along the fibre axis that is obtained during electropolymerization using nanoscale templates. Thermal conductivity data suggest that, unlike in drawn crystalline fibres, in our fibres the dominant phonon-scattering process at room temperature is still related to structural disorder. Using vertically aligned arrays of nanofibres, we demonstrate effective heat transfer at critical contacts in electronic devices operating under high-power conditions at 200 °C over numerous cycles. PMID:24681778

  1. Highly thermally conductive and mechanically strong graphene fibers.

    PubMed

    Xin, Guoqing; Yao, Tiankai; Sun, Hongtao; Scott, Spencer Michael; Shao, Dali; Wang, Gongkai; Lian, Jie

    2015-09-01

    Graphene, a single layer of carbon atoms bonded in a hexagonal lattice, is the thinnest, strongest, and stiffest known material and an excellent conductor of heat and electricity. However, these superior properties have yet to be realized for graphene-derived macroscopic structures such as graphene fibers. We report the fabrication of graphene fibers with high thermal and electrical conductivity and enhanced mechanical strength. The inner fiber structure consists of large-sized graphene sheets forming a highly ordered arrangement intercalated with small-sized graphene sheets filling the space and microvoids. The graphene fibers exhibit a submicrometer crystallite domain size through high-temperature treatment, achieving an enhanced thermal conductivity up to 1290 watts per meter per kelvin. The tensile strength of the graphene fiber reaches 1080 megapascals. PMID:26339027

  2. Highly thermally conductive and mechanically strong graphene fibers

    NASA Astrophysics Data System (ADS)

    Xin, Guoqing; Yao, Tiankai; Sun, Hongtao; Scott, Spencer Michael; Shao, Dali; Wang, Gongkai; Lian, Jie

    2015-09-01

    Graphene, a single layer of carbon atoms bonded in a hexagonal lattice, is the thinnest, strongest, and stiffest known material and an excellent conductor of heat and electricity. However, these superior properties have yet to be realized for graphene-derived macroscopic structures such as graphene fibers. We report the fabrication of graphene fibers with high thermal and electrical conductivity and enhanced mechanical strength. The inner fiber structure consists of large-sized graphene sheets forming a highly ordered arrangement intercalated with small-sized graphene sheets filling the space and microvoids. The graphene fibers exhibit a submicrometer crystallite domain size through high-temperature treatment, achieving an enhanced thermal conductivity up to 1290 watts per meter per kelvin. The tensile strength of the graphene fiber reaches 1080 megapascals.

  3. The high-order quantum coherence of thermal light

    NASA Astrophysics Data System (ADS)

    Chen, Hui

    Thermal light, such as sunlight, is usually considered classical light. In a macroscopic picture, classical theory successfully explained the first-order coherence phenomena of thermal light. The macroscopic theory, based on the statistical behavior of light intensity fluctuations, however, can only phenomenologically explain the second- or higher-order coherence phenomena of thermal light. This thesis introduces a microscopic quantum picture, based on the interferences of a large number of randomly distributed and randomly radiated subfields, wavepackets or photons, to the study of high-order coherence of thermal light. This thesis concludes that the second-order intensity fluctuation correlation is caused by nonlocal interference: a pair of wavepackets, which are randomly paired together, interferes with the pair itself at two distant space-time coordinates. This study has the following practical motivations: (1) to simulate N-qbits. Practical quantum computing requires quantum bits(qubits) of N-digit to represent all possible integers from 0 to 2N-1 simultaneously. A large number of independent particles can be prepared to represent a large set of N orthogonal |0> and |1> bits. In fact, based on our recent experiments of simulating the high-order correlation of entangled photons, thermal radiation is suggested as a promising source for quantum information processing. (2) to achieve sunlight ghost imaging. Ghost imaging has three attractive non-classical features: (a) the ghost camera can "see" targets that can never be seen by a classic camera; (2) it is turbulence-free; and (3) its spatial resolution is mainly determined by the angular diameter of the light source. For example, a sunlight ghost image of an object on earth may achieve a spatial resolution of 200 micrometer because the angular diameter of sun is 0.53 degree with respect to Earth. Although ghost imaging has been experimental demonstrated by using entangled photon pairs and "pseudo-thermal light

  4. Graphene oxide immobilized enzymes show high thermal and solvent stability

    NASA Astrophysics Data System (ADS)

    Hermanová, Soňa; Zarevúcká, Marie; Bouša, Daniel; Pumera, Martin; Sofer, Zdeněk

    2015-03-01

    The thermal and solvent tolerance of enzymes is highly important for their industrial use. We show here that the enzyme lipase from Rhizopus oryzae exhibits exceptionally high thermal stability and high solvent tolerance and even increased activity in acetone when immobilized onto a graphene oxide (GO) nanosupport prepared by Staudenmaier and Brodie methods. We studied various forms of immobilization of the enzyme: by physical adsorption, covalent attachment, and additional crosslinking. The activity recovery was shown to be dependent on the support type, enzyme loading and immobilization procedure. Covalently immobilized lipase showed significantly better resistance to heat inactivation (the activity recovery was 65% at 70 °C) in comparison with the soluble counterpart (the activity recovery was 65% at 40 °C). Physically adsorbed lipase achieved over 100% of the initial activity in a series of organic solvents. These findings, showing enhanced thermal stability and solvent tolerance of graphene oxide immobilized enzyme, will have a profound impact on practical industrial scale uses of enzymes for the conversion of lipids into fuels.The thermal and solvent tolerance of enzymes is highly important for their industrial use. We show here that the enzyme lipase from Rhizopus oryzae exhibits exceptionally high thermal stability and high solvent tolerance and even increased activity in acetone when immobilized onto a graphene oxide (GO) nanosupport prepared by Staudenmaier and Brodie methods. We studied various forms of immobilization of the enzyme: by physical adsorption, covalent attachment, and additional crosslinking. The activity recovery was shown to be dependent on the support type, enzyme loading and immobilization procedure. Covalently immobilized lipase showed significantly better resistance to heat inactivation (the activity recovery was 65% at 70 °C) in comparison with the soluble counterpart (the activity recovery was 65% at 40 °C). Physically adsorbed

  5. An innovative system for heating and cooling a gymnasium using integrated photovoltaic-thermal solar collectors

    SciTech Connect

    Fanchiotti, A.; Herkel, S.; Laukamp, H.; Priolo, C.

    1996-11-01

    The paper describes a new solar energy based system to heat and cool a gymnasium and to generate electricity in the city of Palermo, Italy. The gymnasium will be built in 1996 as part of the structures that will host the Universiadi Games in 1997. Main objectives of the project are: (a) to grant better environmental conditions in the area occupied by the public, with limited use of fossil energy; (b) to reduce the temperature of the photovoltaic elements, thus increasing their efficiency. The system consists of an array of 203 m{sup 2} integrated photovoltaic-thermal solar air collectors. In the winter mode of operation, the heated air is passed through the concrete benches where the public is seated. In the summer mode of operation outside air is evaporatively cooled, passed through the benches, then exhausted to the outside after passing through the collectors. The paper presents some of the results obtained by simulating the system at the design stage for winter conditions.

  6. High-field electrical and thermal transport in suspended graphene.

    PubMed

    Dorgan, Vincent E; Behnam, Ashkan; Conley, Hiram J; Bolotin, Kirill I; Pop, Eric

    2013-10-01

    We study the intrinsic transport properties of suspended graphene devices at high fields (≥1 V/μm) and high temperatures (≥1000 K). Across 15 samples, we find peak (average) saturation velocity of 3.6 × 10(7) cm/s (1.7 × 10(7) cm/s) and peak (average) thermal conductivity of 530 W m(-1) K(-1) (310 W m(-1) K(-1)) at 1000 K. The saturation velocity is 2-4 times and the thermal conductivity 10-17 times greater than in silicon at such elevated temperatures. However, the thermal conductivity shows a steeper decrease at high temperature than in graphite, consistent with stronger effects of second-order three-phonon scattering. Our analysis of sample-to-sample variation suggests the behavior of "cleaner" devices most closely approaches the intrinsic high-field properties of graphene. This study reveals key features of charge and heat flow in graphene up to device breakdown at ~2230 K in vacuum, highlighting remaining unknowns under extreme operating conditions. PMID:23387323

  7. High-Field Electrical and Thermal Transport in Suspended Graphene

    NASA Astrophysics Data System (ADS)

    Dorgan, Vincent E.; Behnam, Ashkan; Conley, Hiram J.; Bolotin, Kirill I.; Pop, Eric

    2013-10-01

    We study the intrinsic transport properties of suspended graphene devices at high fields (>1 V/um) and high temperatures (>1000 K). Across 15 samples, we find peak (average) saturation velocity of 3.6x10^7 cm/s (1.7x10^7 cm/s), and peak (average) thermal conductivity of 530 W/m/K (310 W/m/K), at 1000 K. The saturation velocity is 2-4 times and the thermal conductivity 10-17 times greater than in silicon at such elevated temperatures. However, the thermal conductivity shows a steeper decrease at high temperature than in graphite, consistent with stronger effects of second-order three-phonon scattering. Our analysis of sample-to-sample variation suggests the behavior of "cleaner" devices most closely approaches the intrinsic high-field properties of graphene. This study reveals key features of charge and heat flow in graphene up to device breakdown at ~2230 K in vacuum, highlighting remaining unknowns under extreme operating conditions.

  8. High-Rise Buildings versus Outdoor Thermal Environment in Chongqing

    PubMed Central

    Lu, Jun; Chen, Jin-hua; Tang, Ying; Feng, Yuan; Wang, Jin-sha

    2007-01-01

    This paper gives a brief description of the over quick urbanization since Chongqing, one of the biggest cities in China, has been a municipality directly under the Central Government in 1997, excessive development and exceeding increase of high-rise buildings because of its special geographical position which finally leads to the worsening of the urban outdoor thermal environment. Then, this paper makes a bright balance to the field measurement and simulated results of the wind speed field, temperature field of one multifunctional high-rise building in Chongqing university located in the city center, and the contrasted results validate the correctness of CFD in the outdoor thermal environmental simulation, expose the disadvantages of high-rise buildings on the aspects of blocking the wind field, decreasing wind speed which results in accumulation of the air-conditioning heat revolving around and periscian region where sunshine can not rip into. Finally, in order to improve the urban outdoor thermal environment near the high-rise buildings especially for the angle of natural ventilation, this paper simulates the wind environment in different architectural compositions and architectural layouts by CFD, and the simulated results show that freestyle and tower buildings which can guarantee the wind speed and take the air-conditioning heat away are much suitable and reasonable for the special Chongqing geography. These conclusions can also be used as a reference in other mountain cities, especially for the one with a great number of populations.

  9. Ultra high energy neutrinos: absorption, thermal effects and signatures

    SciTech Connect

    Lunardini, Cecilia; Sabancilar, Eray; Yang, Lili E-mail: Eray.Sabancilar@asu.edu

    2013-08-01

    We study absorption of ultra high energy neutrinos by the cosmic neutrino background, with full inclusion of the effect of the thermal distribution of the background on the resonant annihilation channel. For a hierarchical neutrino mass spectrum (with at least one neutrino with mass below ∼ 10{sup −2} eV), thermal effects are important for ultra high energy neutrino sources at z∼>16. The neutrino transmission probability shows no more than two separate suppression dips since the two lightest mass eigenstates contribute as a single species when thermal effects are included. Results are applied to a number of models of ultra high energy neutrino emission. Suppression effects are strong for sources that extend beyond z ∼ 10, which can be realized for certain top down scenarios, such as superheavy dark matter decays, cosmic strings and cosmic necklaces. For these, a broad suppression valley should affect the neutrino spectrum at least in the energy interval 10{sup 12}−10{sup 13} GeV — which therefore is disfavored for ultra high energy neutrino searches — with only a mild dependence on the neutrino mass spectrum and hierarchy. The observation of absorption effects would indicate a population of sources beyond z ∼ 10, and favor top-down mechanisms; it would also be an interesting probe of the physics of the relic neutrino background in the unexplored redshift interval z ∼ 10–100.

  10. High-temperature ceramic heat exchanger element for a solar thermal receiver

    NASA Technical Reports Server (NTRS)

    Strumpf, H. J.; Kotchick, D. M.; Coombs, M. G.

    1982-01-01

    A study has been completed on the development of a high-temperature ceramic heat exchanger element to be integrated into a solar reciver producing heated air. A number of conceptual designs were developed for heat exchanger elements of differing configuration. These were evaluated with respect to thermal performance, pressure drop, structural integrity, and fabricability. The final design selection identified a finned ceramic shell as the most favorable concept. The ceramic shell is surrounded by a larger metallic shell. The flanges of the two shells are sealed to provide a leak-tight pressure vessel. The ceramic shell is fabricated by an innovative combination of slip casting the receiver walls and precision casting the heat transfer finned plates. The fins are bonded to the shell during firing. Fabrication of a one-half scale demonstrator ceramic receiver has been completed.

  11. High-Fidelity Coupled Monte-Carlo/Thermal-Hydraulics Calculations

    NASA Astrophysics Data System (ADS)

    Ivanov, Aleksandar; Sanchez, Victor; Ivanov, Kostadin

    2014-06-01

    Monte Carlo methods have been used as reference reactor physics calculation tools worldwide. The advance in computer technology allows the calculation of detailed flux distributions in both space and energy. In most of the cases however, those calculations are done under the assumption of homogeneous material density and temperature distributions. The aim of this work is to develop a consistent methodology for providing realistic three-dimensional thermal-hydraulic distributions by coupling the in-house developed sub-channel code SUBCHANFLOW with the standard Monte-Carlo transport code MCNP. In addition to the innovative technique of on-the fly material definition, a flux-based weight-window technique has been introduced to improve both the magnitude and the distribution of the relative errors. Finally, a coupled code system for the simulation of steady-state reactor physics problems has been developed. Besides the problem of effective feedback data interchange between the codes, the treatment of temperature dependence of the continuous energy nuclear data has been investigated.

  12. Innovative high pressure gas MEM's based neutron detector for ICF and active SNM detection.

    SciTech Connect

    Martin, Shawn Bryan; Derzon, Mark Steven; Renzi, Ronald F.; Chandler, Gordon Andrew

    2007-12-01

    An innovative helium3 high pressure gas detection system, made possible by utilizing Sandia's expertise in Micro-electrical Mechanical fluidic systems, is proposed which appears to have many beneficial performance characteristics with regards to making these neutron measurements in the high bremsstrahlung and electrical noise environments found in High Energy Density Physics experiments and especially on the very high noise environment generated on the fast pulsed power experiments performed here at Sandia. This same system may dramatically improve active WMD and contraband detection as well when employed with ultrafast (10-50 ns) pulsed neutron sources.

  13. Strength of VGCF/Al Composites for High Thermal Conductivity

    NASA Astrophysics Data System (ADS)

    Fukuchi, Kohei; Sasaki, Katsuhiko; Imanishi, Terumitsu; Katagiri, Kazuaki; Kakitsuji, Atsushi; Shimizu, Akiyuki

    In this paper, the evaluation of the strength of the VGCF/Aluminum composites which have high thermal conductivity is reported. VGCF (Vapor Growth Carbon Fiber) is a kind of the Carbon nanotube (CNT) which has very high thermal conductivity as well as CNT. The composites are made by spark plasma sintering. The stress-strain curves of the composites are obtained by the tensile tests and show that the composites have brittle behavior. The brittleness of the composites increases with increase in the volume fraction of VGCF. A numerical simulation based on the micromechanics is conducted to estimate nonlinear behavior in the elastic deformation and plastic deformation of the stress-strain relations of the composites. The theories of Eshelby, Mori-Tanaka, Weibull, and Ramberg-Osgood are employed for the numerical simulation. The simulations give some information of the microstructural change in the composite related to the volume fraction of VGCF.

  14. Thermal effects in high average power optical parametric amplifiers.

    PubMed

    Rothhardt, Jan; Demmler, Stefan; Hädrich, Steffen; Peschel, Thomas; Limpert, Jens; Tünnermann, Andreas

    2013-03-01

    Optical parametric amplifiers (OPAs) have the reputation of being average power scalable due to the instantaneous nature of the parametric process (zero quantum defect). This Letter reveals serious challenges originating from thermal load in the nonlinear crystal caused by absorption. We investigate these thermal effects in high average power OPAs based on beta barium borate. Absorption of both pump and idler waves is identified to contribute significantly to heating of the nonlinear crystal. A temperature increase of up to 148 K with respect to the environment is observed and mechanical tensile stress up to 40 MPa is found, indicating a high risk of crystal fracture under such conditions. By restricting the idler to a wavelength range far from absorption bands and removing the crystal coating we reduce the peak temperature and the resulting temperature gradient significantly. Guidelines for further power scaling of OPAs and other nonlinear devices are given. PMID:23455291

  15. The coefficient of thermal expansion of highly enriched 28Si

    NASA Astrophysics Data System (ADS)

    Bartl, Guido; Nicolaus, Arnold; Kessler, Ernest; Schödel, René; Becker, Peter

    2009-10-01

    For the new definition of the SI unit of mass based on a fundamental constant, a redetermination of Avogadro's constant is the goal of an international collaboration of numerous national laboratories and universities. Since a relative uncertainty of about 2 × 10-8 is aimed at, the macroscopic density, the isotopic composition and the volume of the unit cell of a silicon single crystal have to be measured with high precision. One step to improve the precision was the production of a silicon crystal of highly enriched 28Si. This paper addresses the effect of thermal expansion of that material in order to account for a possible discrepancy between the coefficient of thermal expansion (CTE) of natural silicon and that of 28Si. The results of two independent CTE measuring methods are presented and compared in this paper.

  16. High temperature solar thermal technology: The North Africa Market

    SciTech Connect

    Not Available

    1990-12-01

    High temperature solar thermal (HTST) technology offers an attractive option for both industrialized and non-industrialized countries to generate electricity and industrial process steam. The purpose of this report is to assess the potential market for solar thermal applications in the North African countries of Algeria, Egypt, Morocco and Tunisia. North Africa was selected because of its outstanding solar resource base and the variety of applications to be found there. Diminishing oil and gas resources, coupled with expanding energy needs, opens a large potential market for the US industry. The US high temperature solar trough industry has little competition globally and could build a large market in these areas. The US is already familiar with certain solar markets in North Africa due to the supplying of substantial quantities of US-manufactured flat plate collectors to this region.

  17. Thermal lens effects on highly pumped Yb:glass

    NASA Astrophysics Data System (ADS)

    Nishimura, Akihiko; Akaoka, Katsuaki; Ohzu, Akira; Sugiyama, Akira; Usami, Tsutomu; Matoba, Tohru

    2000-04-01

    Thermal lens effects on highly pumped Yb doped phosphate glass was measured by a Shack-Hartmann wavefront sensor for the development of compact chirped pulse amplification systems. High energy pump pulses of 1 - 2 Joules were produced by a flashlamp pumped Ti-sapphire laser. The pumping intensity on the Yb:glass surface exceeded 800 kW/cm2. The pulse energy of 330 mJ from Yb:glass was obtained with 53% slope efficiency with 0.5 Hz reputation. The absorbed pump energy generated the thermal lens effects inside the Yb:glass. The wavefront distortion completely disappeared after 300 ms of pump pulse. Neither heat accumulation nor pumping damage was observed on the Yb:glass.

  18. Developing a High Thermal Conductivity Fuel with Silicon Carbide Additives

    SciTech Connect

    baney, Ronald; Tulenko, James

    2012-11-20

    The objective of this research is to increase the thermal conductivity of uranium oxide (UO{sub 2}) without significantly impacting its neutronic properties. The concept is to incorporate another high thermal conductivity material, silicon carbide (SiC), in the form of whiskers or from nanoparticles of SiC and a SiC polymeric precursor into UO{sub 2}. This is expected to form a percolation pathway lattice for conductive heat transfer out of the fuel pellet. The thermal conductivity of SiC would control the overall fuel pellet thermal conductivity. The challenge is to show the effectiveness of a low temperature sintering process, because of a UO{sub 2}-SiC reaction at 1,377°C, a temperature far below the normal sintering temperature. Researchers will study three strategies to overcome the processing difficulties associated with pore clogging and the chemical reaction of SiC and UO{sub 2} at temperatures above 1,300°C:

  19. Thermal transport measurements in high-energy-density matter

    NASA Astrophysics Data System (ADS)

    Ping, Yuan

    2015-11-01

    Thermal conductivity is one of the most fundamental physical properties of matter. It determines the heat transport rate and has an enormous impact on a variety of mechanical, electrical, chemical, and nuclear systems. Thermal conduction is important in high energy density (HED) matter such as laboratory fusion plasmas, planetary cores, compact stars, and other celestial objects. Examples are in the ablation and instability growth in inertial confinement fusion (ICF) capsules, in energy loss from ICF hot spot, and in the evolution of Earth's core-mantle boundary. Despite the importance of thermal conductivity in HED systems, experimental measurements under relevant conditions are scarce and challenging. We have developed a method of differential heating for thermal conductivity measurements. In this talk, experimental designs will be described for four different platforms: optical laser heating, proton heating, laser-generated x-ray heating and XFEL heating. Data from various facilities will be presented and comparison with models will be discussed. This work was performed under DOE contract DE-AC52-07NA27344 with support from OFES Early Career program and LLNL LDRD program.

  20. Do high-velocity clouds form by thermal instability?

    NASA Astrophysics Data System (ADS)

    Binney, James; Nipoti, Carlo; Fraternali, Filippo

    2009-08-01

    We examine the proposal that the HI `high-velocity' clouds (HVCs) surrounding the Milky Way and other disc galaxies form by condensation of the hot galactic corona via thermal instability. Under the assumption that the galactic corona is well represented by a non-rotating, stratified atmosphere, we find that for this formation mechanism to work the corona must have an almost perfectly flat entropy profile. In all other cases, the growth of thermal perturbations is suppressed by a combination of buoyancy and thermal conduction. Even if the entropy profile were nearly flat, cold clouds with sizes smaller than 10kpc could form in the corona of the Milky Way only at radii larger than 100kpc, in contradiction with the determined distances of the largest HVC complexes. Clouds with sizes of a few kpc can form in the inner halo only in low-mass systems. We conclude that unless even slow rotation qualitatively changes the dynamics of a corona, thermal instability is unlikely to be a viable mechanism for formation of cold clouds around disc galaxies.

  1. Organic transistors with high thermal stability for medical applications

    NASA Astrophysics Data System (ADS)

    Kuribara, Kazunori; Wang, He; Uchiyama, Naoya; Fukuda, Kenjiro; Yokota, Tomoyuki; Zschieschang, Ute; Jaye, Cherno; Fischer, Daniel; Klauk, Hagen; Yamamoto, Tatsuya; Takimiya, Kazuo; Ikeda, Masaaki; Kuwabara, Hirokazu; Sekitani, Tsuyoshi; Loo, Yueh-Lin; Someya, Takao

    2012-03-01

    The excellent mechanical flexibility of organic electronic devices is expected to open up a range of new application opportunities in electronics, such as flexible displays, robotic sensors, and biological and medical electronic applications. However, one of the major remaining issues for organic devices is their instability, especially their thermal instability, because low melting temperatures and large thermal expansion coefficients of organic materials cause thermal degradation. Here we demonstrate the fabrication of flexible thin-film transistors with excellent thermal stability and their viability for biomedical sterilization processes. The organic thin-film transistors comprise a high-mobility organic semiconductor, dinaphtho[2,3-b:2‧,3‧-f]thieno[3,2-b]thiophene, and thin gate dielectrics comprising a 2-nm-thick self-assembled monolayer and a 4-nm-thick aluminium oxide layer. The transistors exhibit a mobility of 1.2 cm2 V-1s-1 within a 2 V operation and are stable even after exposure to conditions typically used for medical sterilization.

  2. High temperature thermal energy storage in steel and sand

    NASA Technical Reports Server (NTRS)

    Turner, R. H.

    1979-01-01

    The technical and economic potential for high temperature (343 C, 650 F) thermal energy storage in hollow steel ingots, pipes embedded in concrete, and for pipes buried in sand was evaluated. Because it was determined that concrete would separate from pipes due to thermal stresses, concrete was replaced by sand, which is free from thermal stresses. Variations of the steel ingot concept were not cost effective compared to the sand-pipe approach, therefore, the sand-pipe thermal storage unit (TSU) was evaluated in depth to assess the approximate tube spacing requirements consistent with different system performance characteristics and also attendant system costs. For large TSUs which do not require fast response times, the sand-pipe approach offers attractive possibilities. A pipe diameter about 9 cm (3.5 in) and pipe spacing of approximately 25 cm (10 in), with sand filling the interspaces, appears appropriate. Such a TSU system designed for 8 hours charge/discharge cycle has an energy unit storage cost (CE) of $2.63/kWhr-t and a power unit storage cost (Cp) of $42/kW-t (in 1977 dollars).

  3. High temperature thermal properties for metals used in LWR vessels

    NASA Astrophysics Data System (ADS)

    Rempe, J. L.; Knudson, D. L.

    2008-01-01

    Because of the impact that melt relocation and vessel failure has on subsequent progression and associated consequences of a light water reactor (LWR) accident, it is important to accurately predict the heatup and relocation of materials within the reactor vessel and heat transfer to and from the reactor vessel. Accurate predictions of such heat transfer phenomena require high temperature thermal properties. However, a review of vessel and structural steel material properties in severe accident analysis codes reveals that the required high temperature material properties are extrapolated with little, if any, data above 700 °C. To reduce uncertainties in predictions relying upon this extrapolated high temperature data, INL obtained data using laser-flash thermal diffusivity techniques for two metals used in LWR vessels: SA 533 Grade B, Class 1 (SA533B1) low alloy steel, which is used to fabricate most US LWR reactor vessels; and Type 304 Stainless Steel SS304, which is used in LWR vessel piping, penetration tubes, and internal structures. This paper summarizes the new data, compares it to existing data in the literature, and provides recommended correlations for thermal properties based on this data.

  4. Thermal conductance of metal-diamond interfaces at high pressure.

    PubMed

    Hohensee, Gregory T; Wilson, R B; Cahill, David G

    2015-01-01

    The thermal conductance of interfaces between metals and diamond, which has a comparatively high Debye temperature, is often greater than can be accounted for by two-phonon processes. The high pressures achievable in a diamond anvil cell (DAC) can significantly extend the metal phonon density of states to higher frequencies, and can also suppress extrinsic effects by greatly stiffening interface bonding. Here we report time-domain thermoreflectance measurements of metal-diamond interface thermal conductance up to 50 GPa in the DAC for Pb, Au0.95Pd0.05, Pt and Al films deposited on type 1A natural [100] and type 2A synthetic [110] diamond anvils. In all cases, the thermal conductances increase weakly or saturate to similar values at high pressure. Our results suggest that anharmonic conductance at metal-diamond interfaces is controlled by partial transmission processes, where a diamond phonon that inelastically scatters at the interface absorbs or emits a metal phonon. PMID:25744853

  5. Fabrication of High Temperature Cermet Materials for Nuclear Thermal Propulsion

    NASA Technical Reports Server (NTRS)

    Hickman, Robert; Panda, Binayak; Shah, Sandeep

    2005-01-01

    Processing techniques are being developed to fabricate refractory metal and ceramic cermet materials for Nuclear Thermal Propulsion (NTP). Significant advances have been made in the area of high-temperature cermet fuel processing since RoverNERVA. Cermet materials offer several advantages such as retention of fission products and fuels, thermal shock resistance, hydrogen compatibility, high conductivity, and high strength. Recent NASA h d e d research has demonstrated the net shape fabrication of W-Re-HfC and other refractory metal and ceramic components that are similar to UN/W-Re cermet fuels. This effort is focused on basic research and characterization to identify the most promising compositions and processing techniques. A particular emphasis is being placed on low cost processes to fabricate near net shape parts of practical size. Several processing methods including Vacuum Plasma Spray (VPS) and conventional PM processes are being evaluated to fabricate material property samples and components. Surrogate W-Re/ZrN cermet fuel materials are being used to develop processing techniques for both coated and uncoated ceramic particles. After process optimization, depleted uranium-based cermets will be fabricated and tested to evaluate mechanical, thermal, and hot H2 erosion properties. This paper provides details on the current results of the project.

  6. NEUTRONIC REACTOR HAVING LOCALIZED AREAS OF HIGH THERMAL NEUTRON DENSITIES

    DOEpatents

    Newson, H.W.

    1958-06-01

    A nuclear reactor for the irradiation of materials designed to provide a localized area of high thermal neutron flux density in which the materials to be irradiated are inserted is described. The active portion of the reactor is comprised of a cubicle graphite moderator of about 25 feet in length along each axis which has a plurality of cylindrical channels for accommodatirg elongated tubular-shaped fuel elements. The fuel elements have radial fins for spacing the fuel elements from the channel walls, thereby providing spaces through which a coolant may be passed, and also to serve as a heatconductirg means. Ducts for accommnodating the sample material to be irradiated extend through the moderator material perpendicular to and between parallel rows of fuel channels. The improvement is in the provision of additional fuel element channels spaced midway between 2 rows of the regular fuel channels in the localized area surrounding the duct where the high thermal neutron flux density is desired. The fuel elements normally disposed in the channels directly adjacent the duct are placed in the additional channels, and the channels directly adjacent the duct are plugged with moderator material. This design provides localized areas of high thermal neutron flux density without the necessity of providing additional fuel material.

  7. Metal Hydride Thermal Storage: Reversible Metal Hydride Thermal Storage for High-Temperature Power Generation Systems

    SciTech Connect

    2011-12-05

    HEATS Project: PNNL is developing a thermal energy storage system based on a Reversible Metal Hydride Thermochemical (RMHT) system, which uses metal hydride as a heat storage material. Heat storage materials are critical to the energy storage process. In solar thermal storage systems, heat can be stored in these materials during the day and released at night—when the sun is not out—to drive a turbine and produce electricity. In nuclear storage systems, heat can be stored in these materials at night and released to produce electricity during daytime peak-demand hours. PNNL’s metal hydride material can reversibly store heat as hydrogen cycles in and out of the material. In a RHMT system, metal hydrides remain stable in high temperatures (600- 800°C). A high-temperature tank in PNNL’s storage system releases heat as hydrogen is absorbed, and a low-temperature tank stores the heat until it is needed. The low-cost material and simplicity of PNNL’s thermal energy storage system is expected to keep costs down. The system has the potential to significantly increase energy density.

  8. High Energy Density Thermal Batteries: Thermoelectric Reactors for Efficient Automotive Thermal Storage

    SciTech Connect

    2011-11-15

    HEATS Project: Sheetak is developing a new HVAC system to store the energy required for heating and cooling in EVs. This system will replace the traditional refrigerant-based vapor compressors and inefficient heaters used in today’s EVs with efficient, light, and rechargeable hot-and-cold thermal batteries. The high energy density thermal battery—which does not use any hazardous substances—can be recharged by an integrated solid-state thermoelectric energy converter while the vehicle is parked and its electrical battery is being charged. Sheetak’s converters can also run on the electric battery if needed and provide the required cooling and heating to the passengers—eliminating the space constraint and reducing the weight of EVs that use more traditional compressors and heaters.

  9. Highly defective oxides as sinter resistant thermal barrier coating

    DOEpatents

    Subramanian, Ramesh

    2005-08-16

    A thermal barrier coating material formed of a highly defective cubic matrix structure having a concentration of a stabilizer sufficiently high that the oxygen vacancies created by the stabilizer interact within the matrix to form multi-vacancies, thereby improving the sintering resistance of the material. The concentration of stabilizer within the cubic matrix structure is greater than that concentration of stabilizer necessary to give the matrix a peak ionic conductivity value. The concentration of stabilizer may be at least 30 wt. %. Embodiments include a cubic matrix of zirconia stabilized by at least 30-50 wt. % yttria, and a cubic matrix of hafnia stabilized by at least 30-50 wt. % gadolinia.

  10. Effective Thermal Conductivity of High Porosity Open Cell Nickel Foam

    NASA Technical Reports Server (NTRS)

    Sullins, Alan D.; Daryabeigi, Kamran

    2001-01-01

    The effective thermal conductivity of high-porosity open cell nickel foam samples was measured over a wide range of temperatures and pressures using a standard steady-state technique. The samples, measuring 23.8 mm, 18.7 mm, and 13.6 mm in thickness, were constructed with layers of 1.7 mm thick foam with a porosity of 0.968. Tests were conducted with the specimens subjected to temperature differences of 100 to 1000 K across the thickness and at environmental pressures of 10(exp -4) to 750 mm Hg. All test were conducted in a gaseous nitrogen environment. A one-dimensional finite volume numerical model was developed to model combined radiation/conduction heat transfer in the foam. The radiation heat transfer was modeled using the two-flux approximation. Solid and gas conduction were modeled using standard techniques for high porosity media. A parameter estimation technique was used in conjunction with the measured and predicted thermal conductivities at pressures of 10(exp -4) and 750 mm Hg to determine the extinction coefficient, albedo of scattering, and weighting factors for modeling the conduction thermal conductivity. The measured and predicted conductivities over the intermediate pressure values differed by 13%.

  11. High-precision thermal and electrical characterization of thermoelectric modules

    SciTech Connect

    Kolodner, Paul

    2014-05-15

    This paper describes an apparatus for performing high-precision electrical and thermal characterization of thermoelectric modules (TEMs). The apparatus is calibrated for operation between 20 °C and 80 °C and is normally used for measurements of heat currents in the range 0–10 W. Precision thermometry based on miniature thermistor probes enables an absolute temperature accuracy of better than 0.010 °C. The use of vacuum isolation, thermal guarding, and radiation shielding, augmented by a careful accounting of stray heat leaks and uncertainties, allows the heat current through the TEM under test to be determined with a precision of a few mW. The fractional precision of all measured parameters is approximately 0.1%.

  12. High thermal-transport capacity heat pipes for space radiators

    NASA Technical Reports Server (NTRS)

    Carlson, Albert W.; Gustafson, Eric; Roukis, Susan L.

    1987-01-01

    This paper presents the results of performance tests of several dual-slot heat pipe test articles. The dual-slot configuration has a very high thermal transport capability and has been identified as a very promising candidate for the radiator system for the NASA Space Station solar dynamic power modules. Two six-foot long aluminum heat pipes were built and tested with ammonia and acetone. A 20-ft long heat pipe was also built and tested with ammonia. The test results have been compared with performance predictions. A thermal transport capacity of 2000 W at an adverse tilt of 1 in. and a 1000 W capacity at an adverse tilt of 2 in. were achieved on the 20-ft long heat pipe. These values are in close agreement with the predicted performance limits.

  13. Thermal Hydraulics of the Very High Temperature Gas Cooled Reactor

    SciTech Connect

    Chang Oh; Eung Kim; Richard Schultz; Mike Patterson; Davie Petti

    2009-10-01

    The U.S Department of Energy (DOE) is conducting research on the Very High Temperature Reactor (VHTR) design concept for the Next Generation Nuclear Plant (NGNP) Project. The reactor design will be a graphite moderated, thermal neutron spectrum reactor that will produce electricity and hydrogen in a highly efficient manner. The NGNP reactor core will be either a prismatic graphite block type core or a pebble bed core. The NGNP will use very high-burnup, low-enriched uranium, TRISO-coated fuel, and have a projected plant design service life of 60 years. The VHTR concept is considered to be the nearest-term reactor design that has the capability to efficiently produce hydrogen. The plant size, reactor thermal power, and core configuration will ensure passive decay heat removal without fuel damage or radioactive material releases during reactor core-accidents. The objectives of the NGNP Project are to: Demonstrate a full-scale prototype VHTR that is commercially licensed by the U.S. Nuclear Regulatory Commission, and Demonstrate safe and economical nuclear-assisted production of hydrogen and electricity. The DOE laboratories, led by the INL, perform research and development (R&D) that will be critical to the success of the NGNP, primarily in the areas of: • High temperature gas reactor fuels behavior • High temperature materials qualification • Design methods development and validation • Hydrogen production technologies • Energy conversion. This paper presents current R&D work that addresses fundamental thermal hydraulics issues that are relevant to a variety of possible NGNP designs.

  14. Thermal Protective Coating for High Temperature Polymer Composites

    NASA Technical Reports Server (NTRS)

    Barron, Andrew R.

    1999-01-01

    The central theme of this research is the application of carboxylate-alumoxane nanoparticles as precursors to thermally protective coatings for high temperature polymer composites. In addition, we will investigate the application of carboxylate-alumoxane nanoparticle as a component to polymer composites. The objective of this research was the high temperature protection of polymer composites via novel chemistry. The significance of this research is the development of a low cost and highly flexible synthetic methodology, with a compatible processing technique, for the fabrication of high temperature polymer composites. We proposed to accomplish this broad goal through the use of a class of ceramic precursor material, alumoxanes. Alumoxanes are nano-particles with a boehmite-like structure and an organic periphery. The technical goals of this program are to prepare and evaluate water soluble carboxylate-alumoxane for the preparation of ceramic coatings on polymer substrates. Our proposed approach is attractive since proof of concept has been demonstrated under the NRA 96-LeRC-1 Technology for Advanced High Temperature Gas Turbine Engines, HITEMP Program. For example, carbon and Kevlar(tm) fibers and matting have been successfully coated with ceramic thermally protective layers.

  15. Extremely High Thermal Conductivity of Aligned Carbon Nanotube-Polyethylene Composites

    PubMed Central

    Liao, Quanwen; Liu, Zhichun; Liu, Wei; Deng, Chengcheng; Yang, Nuo

    2015-01-01

    The ultra-low thermal conductivity of bulk polymers may be enhanced by combining them with high thermal conductivity materials such as carbon nanotubes. Different from random doping, we find that the aligned carbon nanotube-polyethylene composites has a high thermal conductivity by non-equilibrium molecular dynamics simulations. The analyses indicate that the aligned composite not only take advantage of the high thermal conduction of carbon nanotubes, but enhance thermal conduction of polyethylene chains. PMID:26552843

  16. Extremely High Thermal Conductivity of Aligned Carbon Nanotube-Polyethylene Composites

    NASA Astrophysics Data System (ADS)

    Liao, Quanwen; Liu, Zhichun; Liu, Wei; Deng, Chengcheng; Yang, Nuo

    2015-11-01

    The ultra-low thermal conductivity of bulk polymers may be enhanced by combining them with high thermal conductivity materials such as carbon nanotubes. Different from random doping, we find that the aligned carbon nanotube-polyethylene composites has a high thermal conductivity by non-equilibrium molecular dynamics simulations. The analyses indicate that the aligned composite not only take advantage of the high thermal conduction of carbon nanotubes, but enhance thermal conduction of polyethylene chains.

  17. High-strength, thermally-stable nanostructured materials

    NASA Astrophysics Data System (ADS)

    Shankar, Ravi

    The properties of two technologically important precipitation-treatable alloys - Al 6061 and Inconel 718, that are deformed to large plastic strains at room temperature by machining, are presented. The strong effect of prior density of precipitates on the consequent microstructure refinement during chip formation was determined by deforming Al 6061 of different tempers to varying levels of strain, by varying the tool rake angle. Chips cut from peak-aged 6061, consisting of a fine dispersion of precipitates, produced the finest microstructure and are composed of sub-100 nm grains. On the other hand, coarser precipitate distributions in over-aged 6061 and an absence of precipitates in solution-treated 6061 resulted in much coarser microstructures. Thermal stability of such nanostructured chips with different levels of strain and precipitate distributions is analyzed by studying evolution of Vickers micro-hardness and microstructure after different heat treatments. Chips produced from the peak-aged temper and over-aged temper soften following heat treatment while those from the solution-treated state first, gain strength before softening. The results are rationalized based on prior studies of the characteristics and kinetics of precipitation and coarsening in Al-Mg-Si systems. It is then demonstrated that precipitate-stabilized nanostructured materials synthesized from a prototypical alloy system - Inconel 718, are extremely stable even after prolonged heat treatment for 240 hours at temperatures as high as one-half of the melting point. This extraordinary thermal stability is traced to the retention of a fine dispersion of precipitates in a nanostructured matrix even after extended heat treatment. It is anticipated that general design principles garnered from understanding of the causal phenomena determining strengthening and thermal stability, can lead to the development of alloy systems for the manufacture of high-strength, thermally-stable nanostructured materials.

  18. MAGI-L: A Space-Based High-Performance Thermal Infrared Imaging Spectrometer

    NASA Astrophysics Data System (ADS)

    Hall, J. L.; Hackwell, J. A.; Tratt, D. M.; Warren, D. W.; Young, S. J.

    2009-12-01

    An innovative multi-channel, thermal-band imager is proposed for space-based Earth science measurement applications. The low-earth-orbit instrument, MAGI-L (Mineral and Gas Identifier - LEO), would use 28 spectral bands between 7 and 12 microns to both exceed the capabilities of existing spaceborne thermal IR imagers and to enable additional applications, such as detection of gases from natural and anthropogenic sources. The higher spectral resolution, compared to ASTER-type (5 band) sensors, will improve discrimination of rock types, greatly expand the gas-detection capability, and result in more accurate land-surface temperature retrieval (important in evapotranspiration and drought studies) by enabling in-scene atmospheric compensation methods. The smaller pixel size and improved temperature sensitivity of MAGI-L will enable smaller thermal changes to be tracked and weaker gas-emission sources to be monitored, both of which will aid in emission inventory characterization of volcanoes and large industrial complexes, for example. The inclusion of spectral channels near 7 microns will permit better detection of contaminating cirrus clouds at night, when visible sensors are compromised, and will provide a second sulfur dioxide detection channel. To maximize swath width, MAGI-L will use a whiskbroom scanner. The optical design for MAGI-L will incorporate a novel Dyson spectrometer mated to a high-frame-rate 2-D HgCdTe focal plane array. The compact Dyson spectrometer design permits operation at low f-numbers while maintaining very low optical distortions. Data from our airborne SEBASS thermal IR sensor have been used to examine the trade-offs between spectral resolution, spectral range, and instrument sensitivity for the proposed MAGI-L sensor. These studies are being used to guide the design and construction of an airborne demonstrator sensor, MAGI, which is being funded by NASA’s Instrument Incubator Program.

  19. LEDA - A HIGH-POWER TEST BED OF INNOVATION AND OPPORTUNITY

    SciTech Connect

    J. SCHNEIDER; R. SHEFFIELD

    2000-08-01

    The low-energy demonstration accelerator (LEDA) is an operational 6.7-MeV. 100-mA proton accelerator consisting of an injector, radio-frequency quadrupole (RFQ), and all associated integration equipment. In order to achieve this unprecedented level of performance (670-kW of beam power) from an RFQ, a number of design innovations were required. They will highlight a number of those more significant technical advances, including those in the proton injector, the RFQ configuration, the RF klystrons, the beam stop, and the challenges of beam measurements. In addition to identifying the importance of these innovations to LEDA performance, they will summarize the plans for further testing, and the possibilities for addition of more accelerating structures, including the planned use of very-low-beta super-conducting structures. LEDA's current and upgradable configuration is appropriate for several future high-power accelerators, including those for the transmutation of radioactive waste.

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

    SciTech Connect

    Jordan, Eric; Gell, Maurice

    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

  1. Equilibrium statistical-thermal models in high-energy physics

    NASA Astrophysics Data System (ADS)

    Tawfik, Abdel Nasser

    2014-05-01

    We review some recent highlights from the applications of statistical-thermal models to different experimental measurements and lattice QCD thermodynamics that have been made during the last decade. We start with a short review of the historical milestones on the path of constructing statistical-thermal models for heavy-ion physics. We discovered that Heinz Koppe formulated in 1948, an almost complete recipe for the statistical-thermal models. In 1950, Enrico Fermi generalized this statistical approach, in which he started with a general cross-section formula and inserted into it, the simplifying assumptions about the matrix element of the interaction process that likely reflects many features of the high-energy reactions dominated by density in the phase space of final states. In 1964, Hagedorn systematically analyzed the high-energy phenomena using all tools of statistical physics and introduced the concept of limiting temperature based on the statistical bootstrap model. It turns to be quite often that many-particle systems can be studied with the help of statistical-thermal methods. The analysis of yield multiplicities in high-energy collisions gives an overwhelming evidence for the chemical equilibrium in the final state. The strange particles might be an exception, as they are suppressed at lower beam energies. However, their relative yields fulfill statistical equilibrium, as well. We review the equilibrium statistical-thermal models for particle production, fluctuations and collective flow in heavy-ion experiments. We also review their reproduction of the lattice QCD thermodynamics at vanishing and finite chemical potential. During the last decade, five conditions have been suggested to describe the universal behavior of the chemical freeze-out parameters. The higher order moments of multiplicity have been discussed. They offer deep insights about particle production and to critical fluctuations. Therefore, we use them to describe the freeze-out parameters

  2. Thermal Control Method for High-Current Wire Bundles by Injecting a Thermally Conductive Filler

    NASA Technical Reports Server (NTRS)

    Rodriguez-Ruiz, Juan; Rowles, Russell; Greer, Greg

    2011-01-01

    A procedure was developed to inject thermal filler material (a paste-like substance) inside the power wire bundle coming from solar arrays. This substance fills in voids between wires, which enhances the heat path and reduces wire temperature. This leads to a reduced amount of heat generated. This technique is especially helpful for current and future generation high-power spacecraft (1 kW or more), because the heat generated by the power wires is significant enough to cause unacceptable overheating to critical components that are in close contact with the bundle.

  3. Innovative Instrumentation and Analysis of the Temperature Measurement for High Temperature Gasification

    SciTech Connect

    Seong W. Lee

    2005-10-01

    The objectives of this project during this semi-annual reporting period are to test the effects of coating layer of the thermal couple on the temperature measurement and to screen out the significant factors affecting the temperature reading under different operational conditions. The systematic tests of the gasifier simulator on the high velocity oxygen fuel (HVOF) spray coated thermal couples were completed in this reporting period. The comparison tests of coated and uncoated thermal couples were conducted under various operational conditions. The temperature changes were recorded and the temperature differences were calculated to describe the thermal spray coating effect on the thermal couples. To record the temperature data accurately, the computerized data acquisition system (DAS) was adopted to the temperature reading. The DAS could record the data with the accuracy of 0.1 C and the recording parameters are configurable. In these experiments, DAS was set as reading one data for every one (1) minute. The operational conditions are the combination of three parameters: air flow rate, water/ammonia flow rate and the amount of fine dust particles. The results from the temperature readings show the temperature of uncoated thermal couple is uniformly higher than that of coated thermal couple for each operational condition. Analysis of Variances (ANOVA) was computed based on the results from systematic tests to screen out the significant factors and/or interactions. The temperature difference was used as dependent variable and three operational parameters (i.e. air flow rate, water/ammonia flow rate and amount of fine dust particle) were used as independent factors. The ANOVA results show that the operational parameters are not the statistically significant factors affecting the temperature readings which indicate that the coated thermal couple could be applied to temperature measurement in gasifier. The actual temperature reading with the coated thermal couple in

  4. A new high speed thermal imaging concept based on a logarithmic CMOS imager technology

    NASA Astrophysics Data System (ADS)

    Hutter, Franz X.; Brosch, Daniel; Burghartz, Joachim N.; Graf, Heinz-Gerd; Strobel, Markus

    2008-04-01

    HDRC (high dynamic range CMOS) allows for more than 120 dB signal range in image processing. Scene details with both very high and extremely low radiant flux may thus appear within the same image. Color constancy over the entire signal range and good high speed performance are further aspects of this logarithmic imager technology. These features qualify HDRC cameras for thermography, since the signal range of Planck's temperature radiation in a two dimensional array is comparable to HDRC's intensity range. Especially in material welding and laser cutting processes, in high power light sources and in high temperature material processing, fast monitoring of the spacial and dynamic temperature distributions present a challenge to conventional thermal imaging and thus call for innovative concepts. A particular challenge is in the compensation of the emissivity of the radiating surface. Here, we present a new concept based on a modified HDRC VGA color camera, allowing for visualization and measurement of temperatures from about 800 °C up to 2300 °C. The modifications include an optical filter for minimizing UV and IR straylight and a notch filter for clipping off the green optical range in order to separate the blue and red RGB regions. An enhanced and adapted software provides a division of the neighboured red and blue pixel signals by means of simply subtracting the HDRC signals. As a result the local temperature information of the visualized scene spot is independent of emissivity. This is, to our knowledge, the first demonstration of a high speed thermal imager to date.

  5. Thermal Conductance Engineering for High-Speed TES Microcalorimeters

    NASA Astrophysics Data System (ADS)

    Hays-Wehle, J. P.; Schmidt, D. R.; Ullom, J. N.; Swetz, D. S.

    2016-07-01

    Many current and future applications for superconducting transition-edge sensor (TES) microcalorimeters require significantly faster pulse response than is currently available. X-ray spectroscopy experiments at next-generation synchrotron light sources need to successfully capture very large fluxes of photons, while detectors at free-electron laser facilities need pulse response fast enough to match repetition rates of the source. Additionally, neutrino endpoint experiments such as HOLMES need enormous statistics, yet are extremely sensitive to pile-up effects that can distort spectra. These issues can be mitigated only by fast rising and falling edges. To address these needs, we have designed high-speed TES detectors with novel geometric enhancements to increase the thermal conductance of pixels suspended on silicon nitride membranes. This paper shows that the thermal conductivity can be precisely engineered to values spanning over an order of magnitude to achieve fast thermal relaxation times tailored to the relevant applications. Using these pixel prototypes, we demonstrate decay time constants faster than 100 μ s, while still maintaining spectral resolution of 3 eV FWHM at 1.5 keV. This paper also discusses the trade-offs inherent in reducing the pixel time constant, such as increased bias current leading to degradation in energy resolution, and potential modifications to improve performance.

  6. Thermal Conductance Engineering for High-Speed TES Microcalorimeters

    NASA Astrophysics Data System (ADS)

    Hays-Wehle, J. P.; Schmidt, D. R.; Ullom, J. N.; Swetz, D. S.

    2016-01-01

    Many current and future applications for superconducting transition-edge sensor (TES) microcalorimeters require significantly faster pulse response than is currently available. X-ray spectroscopy experiments at next-generation synchrotron light sources need to successfully capture very large fluxes of photons, while detectors at free-electron laser facilities need pulse response fast enough to match repetition rates of the source. Additionally, neutrino endpoint experiments such as HOLMES need enormous statistics, yet are extremely sensitive to pile-up effects that can distort spectra. These issues can be mitigated only by fast rising and falling edges. To address these needs, we have designed high-speed TES detectors with novel geometric enhancements to increase the thermal conductance of pixels suspended on silicon nitride membranes. This paper shows that the thermal conductivity can be precisely engineered to values spanning over an order of magnitude to achieve fast thermal relaxation times tailored to the relevant applications. Using these pixel prototypes, we demonstrate decay time constants faster than 100 μ s, while still maintaining spectral resolution of 3 eV FWHM at 1.5 keV. This paper also discusses the trade-offs inherent in reducing the pixel time constant, such as increased bias current leading to degradation in energy resolution, and potential modifications to improve performance.

  7. High thermal power density heat transfer apparatus providing electrical isolation at high temperature using heat pipes

    NASA Technical Reports Server (NTRS)

    Morris, J. F. (Inventor)

    1985-01-01

    This invention is directed to transferring heat from an extremely high temperature source to an electrically isolated lower temperature receiver. The invention is particularly concerned with supplying thermal power to a thermionic converter from a nuclear reactor with electric isolation. Heat from a high temperature heat pipe is transferred through a vacuum or a gap filled with electrically nonconducting gas to a cooler heat pipe. If the receiver requires gratr thermal power density, geometries are used with larger heat pipe areas for transmitting and receiving energy than the area for conducting the heat to the thermionic converter. In this way the heat pipe capability for increasing thermal power densities compensates for the comparative low thermal power densities through the electrically nonconducting gap between the two heat pipes.

  8. Measurement of thermal conductivity of Bi2Te3 nanowire using high-vacuum scanning thermal wave microscopy

    NASA Astrophysics Data System (ADS)

    Park, Kyungbae; Hwang, Gwangseok; Kim, Hayeong; Kim, Jungwon; Kim, Woochul; Kim, Sungjin; Kwon, Ohmyoung

    2016-02-01

    With the increasing application of nanomaterials in the development of high-efficiency thermoelectric energy conversion materials and electronic devices, the measurement of the intrinsic thermal conductivity of nanomaterials in the form of nanowires and nanofilms has become very important. However, the current widely used methods for measuring thermal conductivity have difficulties in eliminating the influence of interfacial thermal resistance (ITR) during the measurement. In this study, by using high-vacuum scanning thermal wave microscopy (HV-STWM), we propose a quantitative method for measuring the thermal conductivity of nanomaterials. By measuring the local phase lag of high-frequency (>10 kHz) thermal waves passing through a nanomaterial in a high-vacuum environment, HV-STWM eliminates the measurement errors due to ITR and the distortion due to heat transfer through air. By using HV-STWM, we measure the thermal conductivity of a Bi2Te3 nanowire. Because HV-STWM is quantitatively accurate and its specimen preparation is easier than in the thermal bridge method, we believe that HV-STWM will be widely used for measuring the thermal properties of various types of nanomaterials.

  9. Thermal Stabilization in a High Vacuum Cryogenic Optical System

    NASA Astrophysics Data System (ADS)

    Wallace, Rosa; Cripe, Jonathan; Corbitt, Thomas

    2016-03-01

    The existing technology for gravitational wave detection is limited in part by quantum noise. In our tabletop experiments, we are attempting to lower the noise floor to the quantum limit through the use of a seismically isolated cryogenic high vacuum environment, with the intention of exploring different methods to reduce quantum noise. In the development phase of this environment, we have implemented a customized strategy of ultraviolet irradiation combined with cryogenically cooled radiation shielding to reduce the impact of water vapor and blackbody radiation on the thermal stability of the cryogenic micro-components. Supported by National Science Foundation REU Site #1262890 and CAREER Award #1150531.

  10. Miniaturized high-performance starring thermal imaging system

    NASA Astrophysics Data System (ADS)

    Cabanski, Wolfgang A.; Breiter, Rainer; Mauk, Karl-Heinz; Rode, Werner; Ziegler, Johann; Ennenga, L.; Lipinski, Ulrich M.; Wehrhahn, T.

    2000-07-01

    A high resolution thermal imaging system was developed based on a 384 X 288 mercury cadmium telluride (MCT) mid wave (MWIR) infrared (IR) detection module with a 2 X 2 microscan for improved geometrical resolution. Primary design goal was a long identification range of 3 km and high system performance for adverse weather conditions achieved by a system with small entrance pupil and minimized dimensions to fit for integration in existing apertures of armored vehicles, reconnaissance systems and stabilized platforms. A staring FPA module with its potential for long integration times together with a microscan for improved geometrical resolution provides the answers best fit to these requirements. A robust microscanner was developed to fit for military requirements and integrated with AIM's 384 X 288 MCT MWIR module and data processing. The modules allow for up to 2 ms integration time with 25 Hz frame rate and output a 768 X 576 high resolution CCIR standard image. The video image processing (VIP) provides the calculation power for scene based self learning nonuniformity correction (NUC) algorithms to save calibration sources. This NUC algorithm allows take into account non linear effects for unsurpassed performance in highly dynamic scenes. The detection module and VIP are designed to interface with STN's mature system electronics, used e.g. in hundreds of OPHELIOS thermal camera sets fielded. The system electronics provides a lot of different interface features like double serial control bus (CANBUS) interface, analog and digital outputs as well as different video outputs. The integrated graphic generation part allows to put advanced graphic overlays to the thermal image and also to external video signals via the video input feature. This electronics provides the power supply for the whole thermal imaging system as well as different processor controlled algorithms for field of view or zoom drives, focus drives, athermalization and temperature control of the FLIR. A